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Sample records for ventricular wall stress

  1. Left ventricular wall stress compendium.

    Science.gov (United States)

    Zhong, L; Ghista, D N; Tan, R S

    2012-01-01

    Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models.

  2. Left Ventricular Wall Stress-Mass-Heart Rate Product and Cardiovascular Events in Treated Hypertensive Patients

    DEFF Research Database (Denmark)

    Devereux, Richard B; Bang, Casper N; Roman, Mary J

    2015-01-01

    randomized treatment, the triple product was reduced more by atenolol, with prevalences of elevated triple product of 39% versus 51% on losartan (both P≤0.001). In Cox regression analyses adjusting for age, smoking, diabetes mellitus, and prior stroke, MI, and heart failure, 1 SD lower triple product......In the Losartan Intervention for End Point Reduction in Hypertension (LIFE) study, 4.8 years' losartan- versus atenolol-based antihypertensive treatment reduced left ventricular hypertrophy and cardiovascular end points, including cardiovascular death and stroke. However, there was no difference...... in myocardial infarction (MI), possibly related to greater reduction in myocardial oxygen demand by atenolol-based treatment. Myocardial oxygen demand was assessed indirectly by the left ventricular mass×wall stress×heart rate (triple product) in 905 LIFE participants. The triple product was included as time...

  3. Comparison of the Young-Laplace law and finite element based calculation of ventricular wall stress: implications for postinfarct and surgical ventricular remodeling.

    Science.gov (United States)

    Zhang, Zhihong; Tendulkar, Amod; Sun, Kay; Saloner, David A; Wallace, Arthur W; Ge, Liang; Guccione, Julius M; Ratcliffe, Mark B

    2011-01-01

    Both the Young-Laplace law and finite element (FE) based methods have been used to calculate left ventricular wall stress. We tested the hypothesis that the Young-Laplace law is able to reproduce results obtained with the FE method. Magnetic resonance imaging scans with noninvasive tags were used to calculate three-dimensional myocardial strain in 5 sheep 16 weeks after anteroapical myocardial infarction, and in 1 of those sheep 6 weeks after a Dor procedure. Animal-specific FE models were created from the remaining 5 animals using magnetic resonance images obtained at early diastolic filling. The FE-based stress in the fiber, cross-fiber, and circumferential directions was calculated and compared to stress calculated with the assumption that wall thickness is very much less than the radius of curvature (Young-Laplace law), and without that assumption (modified Laplace). First, circumferential stress calculated with the modified Laplace law is closer to results obtained with the FE method than stress calculated with the Young-Laplace law. However, there are pronounced regional differences, with the largest difference between modified Laplace and FE occurring in the inner and outer layers of the infarct borderzone. Also, stress calculated with the modified Laplace is very different than stress in the fiber and cross-fiber direction calculated with FE. As a consequence, the modified Laplace law is inaccurate when used to calculate the effect of the Dor procedure on regional ventricular stress. The FE method is necessary to determine stress in the left ventricle with postinfarct and surgical ventricular remodeling. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Comparison of Young Laplace law and finite element based calculation of ventricular wall stress: Implications for post infarct and surgical ventricular remodeling

    Science.gov (United States)

    Zhang, Zhihong; Tendulkar, Amod; Sun, Kay; Stander, Nielen; Saloner, David A.; Wallace, Arthur W.; Ge, Liang; Guccione, Julius M.; Ratcliffe, Mark B.

    2010-01-01

    Objectives Both the Young Laplace law and finite element (FE) based methods have been used to calculate left ventricular (LV) wall stress. We tested the hypothesis that the Young Laplace law is able to reproduce results obtained with FE method. Methods Magnetic resonance (MRI) images with non-invasive tags were used to calculate 3D myocardial strain in five sheep 16 weeks after anteroapical myocardial infarction and in one of those sheep 6 weeks after a Dor procedure. Animal specific FE models were created from the remaining five animals using MRI images obtained at early diastolic filling. FE based stress in the fiber, cross fiber and circumferential directions was calculated and compared to stress calculated with (Young Laplace law) and without (Modified Laplace) the assumption that wall thickness is very much less than the radius of curvature. Results First,circumferential stress calculated with the Modified Laplace law is closer to results obtained with the FE method than stress calculated with the Young Laplace law. However, there are pronounced regional differences with the largest difference between Modified Laplace and FE occurring especially in the inner and outer layers of the infarct borderzone. Also, stress calculated with Modified Laplace is very different than stress in the fiber and cross fiber direction calculated with FE. As a consequence, the Modified Laplace law is inaccurate when used to calculate the effect of the Dor procedure on regional ventricular stress. Conclusion The FE method is necessary to determine stress in the LV with post infarct and surgical ventricular remodeling. PMID:21172505

  5. Detection of latent anthracycline-induced cardiotoxicity using left ventricular end-systolic wall stress-velocity of circumferential fiber-shortening relationship.

    Science.gov (United States)

    Mizuno, Reiko; Fujimoto, Shinichi; Saito, Yoshihiko; Okamoto, Yasuyuki

    2014-05-01

    Although cardiotoxicity is a well-known side effect of anthracycline, detection of subclinical impairment of myocardial contractility at the latent stage is difficult. The left ventricular end-systolic wall stress (WS)-velocity of circumferential fiber-shortening (VCF) relationship reflects the load-independent myocardial contractility and can detect sensitively intrinsic abnormalities in myocardial contractility. Usefulness of this relationship in detecting subclinical anthracycline-induced cardiotoxicity has not yet been established. We investigated whether latent anthracycline-induced cardiotoxicity at the subclinical state can be detected by using the WS-VCF relationship in patients receiving anthracycline therapy. We studied 45 patients who had received anthracycline therapy and 40 healthy controls. All patients had preserved left ventricular ejection fraction (LVEF). WS and VCF were measured using echocardiography. VCF was corrected by heart rate. The WS-VCF relationship was derived by linear regression. Patients with data points lying below -2 SD derived from controls were regarded as having impaired intrinsic myocardial contractility. Although VCF was within normal limits in all patients, it was significantly reduced in the patient group overall compared with the control group. On the other hand, WS was significantly increased in the patient group overall compared with the control group. The WS-VCF relationship demonstrated impaired intrinsic myocardial contractility in 24 patients (53.3 %). In more than half of patients with preserved LVEF, impairment of intrinsic myocardial contractility was detected using the WS-VCF relationship, suggesting the presence of latent anthracycline-induced cardiotoxicity. The WS-VCF relationship may be able to detect sensitively latent anthracycline-induced cardiotoxicity at the subclinical stage.

  6. Role of tissue structure on ventricular wall mechanics

    OpenAIRE

    Coppola, Benjamin A.; Omens, Jeffrey H.

    2008-01-01

    It is well known that systolic wall thickening in the inner half of the left ventricular (LV) wall is of greater magnitude than predicted by myofiber contraction alone. Previous studies have related the deformation of the LV wall to the orientation of the laminar architecture. Using this method, wall thickening can be interpreted as the sum of contributions due to extension, thickening, and shearing of the laminar sheets. We hypothesized that the thickening mechanics of the ventricular wall a...

  7. Heterogeneity of left ventricular wall thickening mechanisms.

    Science.gov (United States)

    Cheng, Allen; Nguyen, Tom C; Malinowski, Marcin; Daughters, George T; Miller, D Craig; Ingels, Neil B

    2008-08-12

    Myocardial fibers are grouped into lamina (or sheets) 3 to 4 cells thick. Fiber shortening produces systolic left ventricular (LV) wall thickening primarily by laminar extension, thickening, and shear, but the regional variability and transmural distribution of these 3 mechanisms are incompletely understood. Nine sheep had transmural radiopaque markers inserted into the anterior basal and lateral equatorial LV. Four-dimensional marker dynamics were studied with biplane videofluoroscopy to measure circumferential, longitudinal, and radial systolic strains in the epicardium, midwall, and endocardium. Fiber and sheet angles from quantitative histology allowed transformation of these strains into transmural contributions of sheet extension, thickening, and shear to systolic wall thickening. At all depths, systolic wall thickening in the anterior basal region was 1.6 to 1.9 times that in the lateral equatorial region. Interestingly, however, systolic fiber shortening was identical at each transmural depth in these regions. Endocardial anterior basal sheet thickening was >2 times greater than in the lateral equatorial region (epicardium, 0.16+/-0.15 versus 0.03+/-0.06; endocardium, 0.45+/-0.40 versus 0.17+/-0.09). Midwall sheet extension was >2 times that in the lateral wall (0.22+/-0.12 versus 0.09+/-0.06). Epicardial and midwall sheet shears in the anterior wall were approximately 2 times higher than in the lateral wall (epicardium, 0.14+/-0.07 versus 0.05+/-0.03; midwall, 0.21+/-0.12 versus 0.12+/-0.06). These data demonstrate fundamentally different regional contributions of laminar mechanisms for amplifying fiber shortening to systolic wall thickening. Systolic fiber shortening was identical at each transmural depth in both the anterior and lateral LV sites. However, systolic wall thickening of the anterior site was much greater than that of the lateral site. Fiber shortening drives systolic wall thickening, but sheet dynamics and orientations are of great

  8. Postinfarction left ventricular free wall rupture repaired successfully.

    Science.gov (United States)

    Tireli, Emin; Kalko, Yusuf; Kafali, Eylül; Basaran, Murat

    2002-09-01

    Left ventricular free wall rupture is a well-recognized complication of myocardial infarction and a frequent cause of death. A 49-year-old man was successfully treated for a left ventricular free wall rupture that occurred on the third day after an anterior myocardial infarction. Concomitant myocardial revascularization was performed.

  9. Disorders of Left Ventricular Trabeculation/Compaction or Right Ventricular Wall Formation

    Science.gov (United States)

    Shieh, Joseph T.C.; Jefferies, John L.; Chin, Alvin J.

    2013-01-01

    Cardiomyopathies are remarkably variable in form. Although hearts may be dilated or hypertrophic, the spectrum of cardiomyopathies includes left ventricular noncompaction/hypertrabeculation and right ventricular wall disorders. These conditions have been increasingly recognized in patients given advances in clinical diagnostics. Here we present information on cardiac pathophysiology, from ventricular wall formation and trabeculae in model organisms to pediatric and adult disease. Many genes to affect the ventricular phenotype, and this has implications for deciphering developmental and disease pathways and for applying testing for clinical care. PMID:23843328

  10. The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output.

    Science.gov (United States)

    Smerup, Morten; Damkjær, Mads; Brøndum, Emil; Baandrup, Ulrik T; Kristiansen, Steen Buus; Nygaard, Hans; Funder, Jonas; Aalkjær, Christian; Sauer, Cathrine; Buchanan, Rasmus; Bertelsen, Mads Frost; Østergaard, Kristine; Grøndahl, Carsten; Candy, Geoffrey; Hasenkam, J Michael; Secher, Niels H; Bie, Peter; Wang, Tobias

    2016-02-01

    Giraffes--the tallest extant animals on Earth--are renowned for their high central arterial blood pressure, which is necessary to secure brain perfusion. Arterial pressure may exceed 300 mmHg and has historically been attributed to an exceptionally large heart. Recently, this has been refuted by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It thus remains unexplained how the normal-sized giraffe heart generates such massive arterial pressures. We hypothesized that giraffe hearts have a small intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min(-1), respectively. End-diastolic and end-systolic volumes were 521±61 ml and 228±42 ml, respectively, yielding an ejection fraction of 56±4% and a stroke volume of 0.59 ml kg(-1). Left ventricular circumferential wall stress was 7.83±1.76 kPa. We conclude that, relative to body mass, a small left ventricular cavity and a low stroke volume characterizes the giraffe heart. The adaptations result in typical mammalian left ventricular wall tensions, but produce a lowered cardiac output. © 2016. Published by The Company of Biologists Ltd.

  11. Role of tissue structure on ventricular wall mechanics.

    Science.gov (United States)

    Coppola, Benjamin A; Omens, Jeffrey H

    2008-09-01

    It is well known that systolic wall thickening in the inner half of the left ventricular (LV) wall is of greater magnitude than predicted by myofiber contraction alone. Previous studies have related the deformation of the LV wall to the orientation of the laminar architecture. Using this method, wall thickening can be interpreted as the sum of contributions due to extension, thickening, and shearing of the laminar sheets. We hypothesized that the thickening mechanics of the ventricular wall are determined by the structural organization of the underlying tissue, and may not be influenced by factors such as loading and activation sequence. To test this hypothesis, we calculated finite strains from biplane cineradiography of transmural markers implanted in apical (n = 22) and basal (n = 12) regions of the canine anterior LV free wall. Strains were referred to three-dimensional laminar microstructural axes measured by histology. The results indicate that sheet angle is of opposite sign in the apical and basal regions, but absolute value differs only in the subepicardium. During systole, shearing and extension of the laminae contribute the most to wall thickening, accounting for >90% (transmural average) at both apex and base. These two types of deformation are also most prominent during diastolic inflation. Increasing afterload has no effect on the pattern of systolic wall thickening, nor does reversing transmural activation sequence. The pattern of wall thickening appears to be a function of the orientation of the laminar sheets, which vary regionally and transmurally. Thus, acute interventions do not appear to alter the contributions of the laminae to wall thickening, providing further evidence that the structural architecture of the ventricular wall is the dominant factor for its regional mechanical function.

  12. Effects of undersized mitral annuloplasty on regional transmural left ventricular wall strains and wall thickening mechanisms.

    Science.gov (United States)

    Cheng, Allen; Nguyen, Tom C; Malinowski, Marcin; Liang, David; Daughters, George T; Ingels, Neil B; Miller, D Craig

    2006-07-04

    Undersized mitral annuloplasty, widely used for ischemic and functional mitral regurgitation (MR), has been proposed as an "annular solution to a ventricular problem." Beyond relief of MR, it is thought to improve global left ventricular (LV) shape, hence potentially reducing myocardial stress and promoting beneficial reverse LV remodeling. We previously observed that undersized annuloplasty inhibited systolic wall thickening at the LV base near the mitral annulus. In this study, we measured the effects of undersized annuloplasty on regional transmural LV wall fiber and sheet strains and wall thickening mechanisms. Nine sheep had transmural radiopaque beadsets surgically inserted into anterobasal and lateral equatorial LV regions, with additional markers silhouetting the LV and mitral annulus. 4-Dimensional marker dynamics were studied with biplane videofluoroscopy before and after tightening an adjustable Paneth-type mitral annuloplasty suture. Transmural circumferential, longitudinal, and radial systolic and remodeling strains in the subepicardium (20% depth), midwall (50%), and subendocardium (80%) in both regions were computed. Fiber and sheet angles from quantitative regional histology allowed transformation of these strains into local fiber (f), sheet (s), and sheet-normal (n) coordinates. Further analysis calculated the transmural contributions of sheet extension (E(ssc)), sheet thickening (E(nnc)), and sheet shear (E(snc)) to systolic wall thickening (E(33)). In the anterobasal region, undersized annuloplasty reduced systolic wall thickening (E33) by &50% at all transmural depths by inhibiting: (1) subendocardial systolic fiber shortening (-0.10+/-0.05 versus -0.04+/-0.05; Pextension (0.22+/-0.12 versus 0.11+/-0.06; Ptransmural sheet shear (subepicardium, -0.14+/-0.07 versus -0.08+/-0.07; midwall, 0.21+/-0.12 versus 0.10+/-0.11; subendocardium, -0.19+/-0.23 versus -0.11+/-0.16; P<0.05). In the remote lateral equatorial region, fiber-sheet strains and E33

  13. Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog.

    Science.gov (United States)

    Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Kagawa, Yumiko; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

    2017-11-01

    A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls.

  14. Left ventricular wall motion in patients with Chagas's disease.

    Science.gov (United States)

    Hammermeister, K E; Caeiro, T; Crespo, E; Palmero, H; Gibson, D G

    1984-01-01

    The effect of early chronic Chagas's disease on the timing and extent of regional left ventricular wall motion was studied with a frame by frame analysis of left ventriculograms in nine patients and compared with those in 19 normal subjects. In all the patients there was hypokinesis or akinesis in the anteroapical region together with delay in the onset of inward movement. Hypokinesis of the proximal inferior segment was also present, but the time of onset of inward motion here was normal. These differences can be explained on the basis of regional asynchrony within the normal left ventricle, where anteroapical wall motion is delayed with respect to that elsewhere. Thus contraction of the diseased anteroapical segment starts against an appreciable pressure and so may be isometric, whereas the affected proximal inferior segment starts contracting earlier against a lower pressure and so is able to shorten. No abnormalities of wall motion were seen during isovolumic relaxation despite segmental involvement, which is a distinctly different finding from that in patients with coronary artery disease. This may be due partly to the absence of incoordinate relaxation in Chagas's disease and partly to myocardial involvement by Chagas's disease in the mid-anterior segment. This is the site of rapid early diastolic wall thinning, which has been put forward as a major mechanism of normal rapid ventricular filling and whose premature activity causes disturbances in regional wall motion before mitral valve opening when relaxation is incoordinate. Thus quantitative analysis of both the timing and amplitude of wall motion indicates fundamental differences between Chagas's disease and coronary artery disease, when a less complex analysis would have shown a similar pattern of segmental dysfunction in both. Since the effect of the same pathological process on wall motion varies with the site of ventricular involvement, the importance of the disturbances seen in Chagas's disease

  15. Mid-Ventricular Variant of Dobutamine-Induced Stress Cardiomyopathy.

    Science.gov (United States)

    Chandraprakasam, Satish; Kanuri, Swapna; Hunter, Claire

    2015-05-01

    Dobutamine stress testing is a commonly used modality in detecting and estimating the prognosis in coronary artery disease (CAD). Although it is well tolerated by most patients, adverse events have been reported. Rarely, transient wall motion abnormalities can occur in the absence of obstructive CAD to suggest stress cardiomyopathy. We report a 48-year-old female with intermittent chest pain. Her physical exam, cardiac enzymes and transthoracic echocardiogram were unremarkable. She underwent dobutamine stress echocardiogram to rule out obstructive CAD. After 40 micrograms (mcg)/kg/minute and 0.5 mg atropine, she complained of intense chest pain and became hypertensive. Stress echocardiogram demonstrated mid-anterior and mid-septal hypokinesis. Emergent coronary angiogram demonstrated normal coronaries. Left ventricular angiogram in the right anterior oblique projection revealed mid-ventricular ballooning during systole with apical and basal hypercontractility. Patient demonstrated excellent recovery with expectant management. The mechanism of mid-variant of Dobutamine-induced stress cardiomyopathy remains unclear. We think that multiple mechanisms are involved and this risk should be considered in patients with comorbid psychiatric conditions and with use of centrally acting stimulants.

  16. [Adverse effects of type B ventricular pre-excitation on ventricular wall motion and left ventricular function: clinical analysis of 9 cases].

    Science.gov (United States)

    Guo, Baojing; Dai, Chencheng; Li, Wenxiu; Xiao, Yanyan; Han, Ling

    2014-04-01

    To analyze the adverse effects of type B ventricular pre-excitation on ventricular wall motion and left ventricular function and its clinical characteristic. The clinical, electrophysiological and echocardiographic characteristics of the 9 cases with type B ventricular pre-excitation before and after ablation seen between March 2011 and March 2013 were analyzed. The patients aged from 3 to 16 years. Five of them were female. Dyschronous left ventricular contraction was demonstrated by M-Mode echocardiography in all of the cases. The basal segments of the interventricular septum turned thin and moved in a manner similar to that of an aneurysm, with typical bulging during end-systole, which was observed in six cases. All patients received successful RFCAs. The locations of the accessory pathways (APs) were the right-sided anteroseptum (n = 2) and the free wall (n = 7). Their physical activities and growth improved greatly in the four cases with coexisting dilated cardiomyopathy (DCM). The echocardiographic data demonstrated that their LV contraction recovered to synchrony shortly after the ablation, LVEF recovered to normal and LVED decreased to almost normal gradually during the follow-up. Overt right-sided APs may have adverse effects on ventricular wall motion and left ventricular function. They can even result in DCM. Dyssynchronous ventricular contraction induced by right-sided overt accessory pathway may be the vital mechanism. Such kinds of cases are indication for ablation with good prognosis.

  17. The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output

    DEFF Research Database (Denmark)

    Smerup, Morten Holdgaard; Damkjær, Mads; Brøndum, Emil

    2016-01-01

    by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It remains enigmatic, however, how the normal-sized giraffe heart generates such massive arterial pressures.We hypothesized that giraffe hearts have a small...... intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic...

  18. Motional Effect on Wall Shear Stresses

    DEFF Research Database (Denmark)

    Kock, Samuel Alberg; Torben Fründ, Ernst; Yong Kim, Won

    Atherosclerosis is the leading cause of death and severe disability. Wall Shear Stress (WSS), the stress exerted on vessel walls by the flowing blood is a key factor in the development of atherosclerosis. Computational Fluid Dynamics (CFD) is widely used for WSS estimations. Most CFD simulations ...

  19. Normal left ventricular wall motion measured with two-dimensional myocardial tagging

    DEFF Research Database (Denmark)

    Qi, P; Thomsen, C; Ståhlberg, F

    1993-01-01

    Using a myocardial tagging technique, normal left ventricular wall motion was studied in 3 true short axis views and a double oblique 4-chamber view in 14 and 11 volunteers, respectively. Three orthogonal directions of left ventricular motion were observed throughout the systole; a concentric...

  20. Sutureless off-pump repair of post-infarction left ventricular free wall rupture

    Directory of Open Access Journals (Sweden)

    Butler Rob

    2006-05-01

    Full Text Available Abstract Left ventricular free wall rupture after myocardial infarction has a high mortality. Suturing techniques of repair may be technically difficult and require cardiopulmonary bypass. We report a case of left ventricular rupture in a 47 year old man managed off pump employing a sutureless technique with Gelatine-Resorcin-Formalin glue and bovine pericardial patches.

  1. Right ventricular wall abscess in structurally normal heart after leg osteomyelitis: First case.

    Science.gov (United States)

    Ahmad, Tanveer; Pasarad, Ashwini Kumar; Kishore, Kolkebaile Sadanand; Maheshwarappa, Nandakumar Neralakere

    2016-09-01

    A 3-year-old girl presented with fever and acute dyspnea for 4 days. She had suffered an injury to the left lower leg 3 weeks earlier, with abscess formation. Magnetic resonance imaging showed osteomyelitis of the lower tibia. Echocardiography showed a mass in the right ventricular wall. She underwent concomitant heart surgery for removal of the right ventricular mass and limb arthrotomy. We believe this is a first reported case in which a ventricular wall abscess developed in a structurally normal heart following leg osteomyelitis. © The Author(s) 2015.

  2. Clinical applications of a quantitative analysis of regional lift ventricular wall motion

    Science.gov (United States)

    Leighton, R. F.; Rich, J. M.; Pollack, M. E.; Altieri, P. I.

    1975-01-01

    Observations were summarized which may have clinical application. These were obtained from a quantitative analysis of wall motion that was used to detect both hypokinesis and tardokinesis in left ventricular cineangiograms. The method was based on statistical comparisons with normal values for regional wall motion derived from the cineangiograms of patients who were found not to have heart disease.

  3. Resolution of lupus-related left ventricular wall thickening and ...

    African Journals Online (AJOL)

    Cardiopulmonary involvement is one of the important manifestations of systemic lupus erythematosus (SLE) that tends to be more common in adults than children with SLE. SLE-related cardiopulmonary affection ranges from subclinical to life threatening condition. Although increased left ventricular mass and interstitial lung ...

  4. Do diabetes mellitus and systemic hypertension predispose to left ventricular free wall rupture in acute myocardial infarction?

    DEFF Research Database (Denmark)

    Melchior, T; Hildebrant, P; Køber, L

    1997-01-01

    Diabetes and systemic hypertension had no influence on left ventricular free wall rupture complicating acute myocardial infarction. Age <65 years and a history of coronary artery disease offers some protection from protection.......Diabetes and systemic hypertension had no influence on left ventricular free wall rupture complicating acute myocardial infarction. Age

  5. Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR.

    Science.gov (United States)

    Codreanu, I; Robson, M D; Rider, O J; Pegg, T J; Dasanu, C A; Jung, B A; Rotaru, N; Clarke, K; Holloway, C J

    2014-05-01

    Obtaining new details of radial motion of left ventricular (LV) segments using velocity-encoding cardiac MRI. Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Cine images for navigator-gated phase contrast velocity mapping were acquired using a black blood segmented κ-space spoiled gradient echo sequence with a temporal resolution of 13.8 ms. Peak systolic and diastolic radial velocities as well as radial velocity curves were obtained for 16 ventricular segments. Significant differences among peak radial velocities of basal and mid-ventricular segments have been recorded. Particular patterns of segmental radial velocity curves were also noted. An additional wave of outward radial movement during the phase of rapid ventricular filling, corresponding to the expected timing of the third heart sound, appeared of particular interest. The technique has allowed visualization of new details of LV radial wall motion. In particular, higher peak systolic radial velocities of anterior and inferior segments are suggestive of a relatively higher dynamics of anteroposterior vs lateral radial motion in systole. Specific patterns of radial motion of other LV segments may provide additional insights into LV mechanics. The outward radial movement of LV segments impacted by the blood flow during rapid ventricular filling provides a potential substrate for the third heart sound. A biphasic radial expansion of the basal anteroseptal segment in early diastole is likely to be related to the simultaneous longitudinal LV displacement by the stretched great vessels following repolarization and their close apposition to this segment.

  6. Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, Thomas S. [Department of Radiology, Diagnostic Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: tskaarup@yahoo.com; Kofoed, Klaus F. [Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: kkofoed@dadlnet.dk; Moller, Daniel V. [Department of Cardiology, Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: DVEGA@gmx.net; Ersboll, Mads [Department of Cardiology, Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: ersboell@stud.ku.dk; Kuehl, Tobias [Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: tobiaskh@gmail.com; Recke, Peter von der [Department of Radiology, Diagnostic Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: peter.von.der.recke@rh.regionh.dk; Kober, Lars [Department of Cardiology, Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: lk@heart.dk; Nielsen, Michael B. [Department of Radiology, Diagnostic Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: mbn@dadlnet.dk; Kelbaek, Henning [Department of Cardiology, Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)], E-mail: henning.kelbaek@rh.regionh.dk

    2009-10-15

    Background: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic echocardiography (TTE). Materials and methods: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared with visual evaluation of wall motion score (WMS) by TTE. Global SWT by MDCT was calculated as the mean SWT of all myocardial segments and compared with wall motion index (WMI) by TTE. Results: Eight hundred and eleven segments (81%) were classified as normokinetic, 142 (14%) as hypokinetic, 41 (4%) as akinetic and 5 (0.5%) as dyskinetic by TTE. A significant inverse linear trend was found between regional SWT by MDCT and WMS by TTE (p < 0.001). Sensitivity and specificity for the identification of regional abnormalities of contractile function were 76% and 78%, respectively. A linear correlation between global SWT by MDCT and WMI by TTE was found (r = -0.8, p < 0.001). Sensitivity and specificity for the identification of WMI > 1.5 using global SWT was 91% and 94%, respectively. Conclusion: Quantification of systolic wall thickening by MDCT provides functional information, which is well correlated to visual assessment of global left ventricular contractile function by TTE.

  7. Coronary flow and left ventricular function during environmental stress.

    Science.gov (United States)

    Erickson, H. H.; Adams, J. D.; Stone, H. L.; Sandler, H.

    1972-01-01

    A canine model was used to study the effects of different environmental stresses on the heart and coronary circulation. The heart was surgically instrumented to measure coronary blood flow, left ventricular pressure, and other cardiovascular variables. Coronary flow was recorded by telemetry. Physiologic data were processed and analyzed by analog and digital computers. By these methods the physiologic response to altitude hypoxia, carbon monoxide, hypercapnia, acceleration, exercise, and the interaction of altitude hypoxia and carbon monoxide were described. The effects of some of these stresses on the heart and coronary circulation are discussed.

  8. Relation of left ventricular free wall rupture and/or aneurysm with acute myocardial infarction in patients with aortic stenosis

    OpenAIRE

    Sheikh, Irtiza N.; Roberts, William C.

    2017-01-01

    This minireview describes 6 previously reported patients with left ventricular free wall rupture and/or aneurysm complicating acute myocardial infarction (AMI) in patients with aortic stenosis. The findings suggest that left ventricular rupture and/or aneurysm is more frequent in patients with AMI associated with aortic stenosis than in patients with AMI unassociated with aortic stenosis, presumably because of retained elevation of the left ventricular peak systolic pressure after the appeara...

  9. Increased left ventricular torsion in hypertrophic cardiomyopathy mutation carriers with normal wall thickness

    Science.gov (United States)

    2011-01-01

    Background Increased left ventricular (LV) torsion has been observed in patients with manifest familial hypertrophic cardiomyopathy (HCM), and is thought to be caused by subendocardial dysfunction. We hypothesize that increased LV torsion is already present in healthy mutation carriers with normal wall thickness. Methods Seventeen carriers with an LV wall thickness subendocardial myocardial dysfunction. As similar abnormalities are observed in patients with manifest HCM, the changes in healthy carriers may be target for clinical intervention to delay or prevent the onset of hypertrophy. PMID:21219655

  10. Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography

    DEFF Research Database (Denmark)

    Kristensen, Thomas S; Kofoed, Klaus F; Møller, Daniel V

    2009-01-01

    echocardiography (TTE). MATERIALS AND METHODS: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared...... global SWT by MDCT and WMI by TTE was found (r=-0.8, p1.5 using global SWT was 91% and 94%, respectively. CONCLUSION: Quantification of systolic wall thickening by MDCT provides functional information, which is well correlated to visual...

  11. The reliability of echocardiographic left ventricular wall motion index to identify high-risk patients for multicenter studies

    DEFF Research Database (Denmark)

    Gislason, Gunnar H; Gadsbøll, Niels; Quinones, Miguel A

    2006-01-01

    OBJECTIVE: To study whether the use of echocardiographic left ventricular (LV) wall motion index (WMI) is a dependable parameter for identifying patients with LV dysfunction to be enrolled in multicenter trials. METHODS: Videotaped echocardiographic examinations from 200 randomly selected patient...

  12. Computer-based assessment of left ventricular wall stiffness in patients with ischemic dilated cardiomyopathy

    Science.gov (United States)

    Su, Y.; Teo, S. K.; Tan, R. S.; Lim, C. W.; Zhong, L.

    2013-02-01

    Ischemic dilated cardiomyopathy (IDCM) is a degenerative disease of the myocardial tissue accompanied by left ventricular (LV) structural changes such as interstitial fibrosis. This can induce increased passive stiffness of the LV wall. However, quantification of LV passive wall stiffness in vivo is extremely difficult, particularly in ventricles with complex geometry. Therefore, we sought to (i) develop a computer-based assessment of LV passive wall stiffness from cardiac magnetic resonance (CMR) imaging in terms of a nominal stiffness index (E*); and (ii) investigate whether E* can offer an insight into cardiac mechanics in IDCM. CMR scans were performed in 5 normal subjects and 5 patients with IDCM. For each data sample, an in-house software was used to generate a 1-to-1 corresponding mesh pair of the LV from the ED and ES phases. The E* values are then computed as a function of local ventricular wall strain. We found that E* in the IDCM group (40.66 - 215.12) was at least one order of magnitude larger than the normal control group (1.00 - 6.14). In addition, the IDCM group revealed much higher inhomogeneity of E* values manifested by a greater spread of E* values throughout the LV. In conclusion, there is a substantial elevated ventricular stiffness index in IDCM. This would suggest that E* could be used as discriminator for early detection of disease state. The computational performance per data sample took approximately 25 seconds, which demonstrates its clinical potential as a real-time cardiac assessment tool.

  13. Regional evaluation of the left ventricular wall motion by radionuclide ventriculography

    Energy Technology Data Exchange (ETDEWEB)

    Tarkowska, A. (Akademia Medyczna, Lublin (Poland)); Adam, W.E.; Bitter, F.; Geffers, H.; Garvie, N.W. (Ulm Univ. (Germany, F.R.). Sektion Nuklearmedizin)

    1982-02-01

    ECG gated radionuclide ventriculography was performed in 85 patients with heart disease, after in vivo red cell labelling with sodium stannous pyrophosphate and 670-740 MBq /sup 99/Tcsup(m) pertechnetate. From the analysis of time activity curves of each pixel, sets of parametric scans were displayed. Of 496 parametric scans, 192 were normal and 304 showed wall motion abnormalities. There was good correlation between the individual parametric scans (r >= 0.815) and between parametric scans and contrast ventriculograms (r >= 0.631) in the occurrence and extent of regional wall motion abnormalities. The highest sensitivity was revealed by the peak filling rate (relaxation velocity) scan. The best specificity was shown by scans using the amplitude and phase of the first Fourier element. Good results were obtained by a combination of four parametric images. The ability of the phase scan to detect local dyskinesis may be better than that of the contrast ventriculogram. Changes in parametric scans were related to, but preceded, impairment of left ventricular function (r >= -0.513). It is concluded that parametric scans provide a reliable, objective and non-invasive method for regional evaluation of left ventricular function, of great use in the diagnosis of local wall motion abnormalities and their effect on the heart performance.

  14. Critical wall shear stress for the EHEDG test method

    DEFF Research Database (Denmark)

    Jensen, Bo Boye Busk; Friis, Alan

    2004-01-01

    In order to simulate the results of practical cleaning tests on closed processing equipment, based on wall shear stress predicted by computational fluid dynamics, a critical wall shear stress is required for that particular cleaning method. This work presents investigations that provide a critical...... wall shear stress of 3 Pa for the standardised EHEDG cleaning test method. The cleaning tests were performed on a test disc placed in a radial flowcell assay. Turbulent flow conditions were generated and the corresponding wall shear stresses were predicted from CFD simulations. Combining wall shear...... stress predictions from a simulation using the low Re k-epsilon and one using the two-layer model of Norris and Reynolds were found to produce reliable predictions compared to empirical solutions for the ideal flow case. The comparison of wall shear stress curves predicted for the real RFC...

  15. Research on wall shear stress considering wall roughness when shear swirling flow vibration cementing

    Science.gov (United States)

    Cui, Zhihua; Ai, Chi; Feng, Fuping

    2017-01-01

    When shear swirling flow vibration cementing, the casing is revolving periodically and eccentrically, which leads to the annulus fluid in turbulent swirling flow state. The wall shear stress is more than that in laminar flow field when conventional cementing. The paper mainly studied the wall shear stress distribution on the borehole wall when shear swirling flow vibration cementing based on the finite volume method. At the same time, the wall roughness affected and changed the turbulent flow near the borehole wall and the wall shear stress. Based on the wall function method, the paper established boundary conditions considering the wall roughness and derived the formula of the wall shear stress. The results showed that the wall roughness significantly increases the wall shear stress. However, the larger the wall roughness, the greater the thickness of mud cake, which weakening the cementing strength. Considering the effects in a comprehensive way, it is discovered that the particle size of solid phase in drilling fluid is about 0.1 mm to get better cementing quality.

  16. Na+ channel distribution and electrophysiological heterogeneities in guinea pig ventricular wall.

    Science.gov (United States)

    Osadchii, Oleg E; Soltysinska, Ewa; Olesen, Soren Peter

    2011-03-01

    We sought to explore the distribution pattern of Na(+) channels across ventricular wall, and to determine its functional correlates, in the guinea pig heart. Voltage-dependent Na(+) channel (Na(v)) protein expression levels were measured in transmural samples of ventricular tissue by Western blotting. Isolated, perfused heart preparations were used to record monophasic action potentials and volume-conducted ECG, and to measure effective refractory periods (ERPs) and pacing thresholds, in order to assess excitability, electrical restitution kinetics, and susceptibility to stimulation-evoked tachyarrhythmias at epicardial and endocardial stimulation sites. In both ventricular chambers, Na(v) protein expression was higher at endocardium than epicardium, with midmyocardial layers showing intermediate expression levels. Endocardial stimulation sites showed higher excitability, as evidenced by lower pacing thresholds during regular stimulation and downward displacement of the strength-interval curve reconstructed after extrasystolic stimulation compared with epicardium. ERP restitution assessed over a wide range of pacing rates showed greater maximal slope and faster kinetics at endocardial than epicardial stimulation sites. Flecainide, a Na(+) channel blocker, reduced the maximal ERP restitution slope, slowed restitution kinetics, and eliminated epicardial-to-endocardial difference in dynamics of electrical restitution. Greater excitability and steeper electrical restitution have been associated with greater arrhythmic susceptibility of endocardium than epicardium, as assessed by measuring ventricular fibrillation threshold, inducibility of tachyarrhythmias by rapid cardiac pacing, and the magnitude of stimulation-evoked repolarization alternans. In conclusion, higher Na(+) channel expression levels may contribute to greater excitability, steeper electrical restitution slopes and faster restitution kinetics, and greater susceptibility to stimulation

  17. Three dimensional quantification of left ventricular wall motion by ECG-gated blood pool emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, S.R.; Walton, S.; Laming, P.J.; Jarritt, P.H.; Ell, P.J.; Emanuel, R.W.; Swanton, R.H.

    1985-05-01

    ECG-gated blood pool emission tomography is a relatively new technique, and this study establishes a simple method for displaying the three dimensional data obtained, determines a normal range for ejection fraction in all regions of the left ventricle, and compares wall motion in abnormal subjects with that determined by X-ray contrast ventriculography. The short axis sections dividing the ventricle in slices from apex to base, were used to calculate ejection fraction for all parts of the ventricle and the results were plotted on a single colour coded circular image. The apex was represented in the centre, the base around the circumference, and all other parts of the ventricle were represented in between. The image was divided into 15 segments, and normal segmental ejection fraction was defined as within two standard deviations of the mean in a group of 10 normal subjects. In 25 subjects with coronary artery disease, motion of the anterior, apical, and inferior walls agreed in every case with the right anterior oblique contrast ventriculogram, but in 12 of these, the three dimensional ejection fraction image showed abnormal septal motion, and in a further 3, abnormal lateral wall motion in addition. In the 12 subjects there was disease of the left anterior descending coronary artery, and in the further 3 there was left circumflex disease. ECG-gated blood pool emission tomography thus provides an accurate quantitative assessment of left ventricular wall motion in three dimensions, and has significant advantages over conventional planar techniques.

  18. Cell Wall Metabolism in Response to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Hyacinthe Le Gall

    2015-02-01

    Full Text Available This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic, transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i an increased level in xyloglucan endotransglucosylase/hydrolase (XTH and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  19. Increased left ventricular torsion in hypertrophic cardiomyopathy mutation carriers with normal wall thickness

    Directory of Open Access Journals (Sweden)

    Marcus Tim J

    2011-01-01

    Full Text Available Abstract Background Increased left ventricular (LV torsion has been observed in patients with manifest familial hypertrophic cardiomyopathy (HCM, and is thought to be caused by subendocardial dysfunction. We hypothesize that increased LV torsion is already present in healthy mutation carriers with normal wall thickness. Methods Seventeen carriers with an LV wall thickness Results LV volumes, mass and circumferential strain were comparable between groups, whereas LV ejection fraction, torsion and TECS-ratio were increased in carriers compared to controls (63 ± 3% vs. 60 ± 3%, p = 0.04, 10.1 ± 2.5° vs. 7.7 ± 1.2°, p = 0.001, and 0.52 ± 0.14°/% vs. 0.42 ± 0.10°/%, p = 0.02, respectively. Conclusions Carriers with normal wall thickness display increased LV torsion and TECS-ratio with respect to controls, which might be due to subendocardial myocardial dysfunction. As similar abnormalities are observed in patients with manifest HCM, the changes in healthy carriers may be target for clinical intervention to delay or prevent the onset of hypertrophy.

  20. Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

    Science.gov (United States)

    Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

    2015-07-28

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

  1. Quantitative evaluation of left ventricular regional wall motion by cardiac cine magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroshi; Okamura, Masahiro; Kondo, Takeshi (Fujita-Gakuen Health Univ., Toyoake, Aichi (Japan)) (and others)

    1991-04-01

    The purpose of this study is to evaluate quantitatively the left ventricular (LV) regional wall motion abnormalities by cardiac cine magnetic resonance imaging (MRI) with the on-line wall motion analysis software that is developed by us. Eighteen patients with various heart diseases were studied by field echo cardiac cine MRI (TR/TE/flip angle = 50/22/30deg) with chain oblique technique. The LV of the right anterior oblique (RAO) left ventriculography (LVG) and vertical long-axis MRI was divided into 5 segments corresponding to those specified by the American Heart Association (AHA), respectively. The area contraction ratio of all segments using LVG and MRI showed significant (p<0.001) positive correlation (r=0.748). As for each segment evaluated independently, correlation was significant (p<0.001) and positive for segments 1 to 3 (r=0.809 in segment 1, r=0.886 in segment 2, and r=0.806 in segment 3). On the other hand, strong correlation was not seen in segment 4 (r=0.712, p<0.001), nor in segment 5 (r=0.698, p<0.002). This was because, due to the absence of respiratory gating, movement of the diaphragm hindered clear delineation of the inferior wall in some cases. In conclusion, the newly developed on-line software permits outlining of LV vertical long-axis images at the end diastole and the end systole, and readily provides quantitative analysis of the LV wall motion. We believe that this method will prove to be useful clinically. (author).

  2. Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2017-05-01

    Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

  3. Endurance rather than sprint running training increases left ventricular wall thickness in female athletes.

    Science.gov (United States)

    Venckunas, Tomas; Raugaliene, Rasa; Mazutaitiene, Birute; Ramoskeviciute, Sonata

    2008-02-01

    Competitive athletics is often associated with moderate left ventricular (LV) hypertrophy. The aim of this study was to shed more light on the extent and type of cardiac hypertrophic response to different athletic conditioning in females. Standard two-dimensional M-mode and Doppler echocardiography was performed at rest in Caucasian female sprinters (n = 10) and long-distance runners (n = 10) of similar age (range 16-34 years), training experience (5-18 years) and competitive level, and in age-matched healthy female sedentary controls (n = 10). No differences in echocardiographic parameters were detected between female sprinters and sedentary controls (p > 0.05). Interventricular septum and LV wall (p sprinters or sedentary controls. Absolute LV diameter was not increased in long-distance runners (p > 0.05), though relative LV diameter was higher in long-distance runners as compared to sprinters (p 0.05). In conclusion, sprint running training has not been found to induce alterations in cardiac morphology or function at rest in female athletes. Cardiac mass in female long-distance runners is higher mainly due to myocardial wall thickening, while integral myocardial function at rest is not affected as a consequence of either this hypertrophy or sprint training.

  4. Determination of surface stress anisotropy from domain wall fluctuations

    NARCIS (Netherlands)

    Zandvliet, Henricus J.W.; Poelsema, Bene

    1999-01-01

    The thermally induced meandering of domain walls between (2×1) and c(4×2) regions on Ge(001) is analyzed with a scanning tunneling microscope in order to extract the anisotropy of the surface stress tensor. On small length scales the domain walls exhibit random walker behavior, whereas on larger

  5. Casimir stress in materials: Hard divergency at soft walls

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-11-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir stress inside bodies. Suppose empty space or a uniform medium meets a soft wall where the refractive index is continuous but its derivative jumps. For this situation we predict a characteristic power law for the stress inside the soft wall and close to its edges. Our result shows that such edges are not tolerated in the aggregation of liquids at surfaces, regardless whether the liquid is attracted or repelled.

  6. Ventricular septal rupture, right ventricular free wall rupture, hemopericardium, cardiac tamponade, cardiogenic shock, and death in a patient with acute ST elevation myocardial infarction during transthoracic echocardiography

    Directory of Open Access Journals (Sweden)

    Osama A El Kady

    2017-01-01

    Full Text Available The incidence of mechanical complications related to myocardial infarction has decreased due to various factors over the last few decades. Patients admitted for acute ST segment elevation myocardial infarction (STEMI may respond well to thrombolytic therapy before being taken up for coronary angiography and percutaneous coronary intervention depending on the facilities available at the specific center. Unfortunately, some patients develop complications of myocardial infarction during hospital stay or postdischarge. We present a patient admitted with acute STEMI responding well to thrombolytic therapy. During transthoracic echocardiography of the patient in Intensive Care Unit, the patient developed ventricular septal rupture, right ventricular free wall rupture, hemopericardium, cardiac tamponade, and cardiogenic shock and expired.

  7. Comparison of dual-source 64-slice adenosine stress CT perfusion with stress-gated SPECT-MPI for evaluation of left ventricular function and volumes.

    Science.gov (United States)

    Uthamalingam, Shanmugam; Gurm, Gagandeep S; Sidhu, Manavjot S; Verdini, Daniel J; Vorasettakarnkij, Yongkasem; Engel, Leif-Christopher; Blankstein, Ron; Mamuya, Wilfred S; Hoffman, Udo; Brady, Thomas J; Cury, Ricardo C; Ghoshhajra, Brian B

    2012-01-01

    Evaluation of left ventricular (LV) volumes and ejection fraction (LVEF) represent important components of pharmacologic stress imaging with either myocardial CT perfusion (CTP) or gated single-photon emission CT (SPECT) myocardial perfusion imaging (SPECT-MPI). We compared measurements of left ventricular function and volumes obtained with CTP and SPECT-MPI. Forty-seven patients (mean age, 62 ± 11 years; male, n = 39) underwent stress CTP and SPECT-MPI. LVEF (in %), end-systolic volume (ESV; in mL), and end-diastolic volume (EDV; in mL) derived from stress CTP images were compared with SPECT-MPI. Stress CTP was in good agreement with SPECT-MPI for quantification of LVEF (r = 0.91), EDV (r = 0.75), and ESV (r = 0.83; all P stress CTP (66% ± 17%) was similar to SPECT-MPI (64% ± 15%). Similar values were also derived for mean EDV (123 ± 30 mL vs 120 ± 34 mL) and ESV (44 ± 28 mL vs 51 ± 34 mL) for CTP and SPECT-MPI, respectively. Good agreement was also shown between both techniques for the assessment of regional wall motion with identical wall motion scores in 95.3% of the segments (κ = 0.79). LVEF and LV volume parameters as determined by dual-source 64-slice adenosine stress CTP show a high correlation with values obtained with stress-gated SPECT-MPI. Copyright © 2012 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  8. Wall shear stress evolution in carotid artery bifurcation

    Science.gov (United States)

    Bernad, S. I.; Bosioc, A. I.; Totorean, A. F.; Petre, I.; Bernad, E. S.

    2017-07-01

    The steady flow in an anatomically realistic human carotid bifurcation was simulated numerically. Main parameters such as wall shear stress (WSS), velocity profiles and pressure distributions are investigated in the carotid artery, namely in bifurcation and sinusoidal enlargement regions. Flow in the carotid sinus is dominated by a single secondary vortex motion accompanied by a strong helical flow. This type of flow is induced primarily by the curvature and asymmetry of the in vivo geometry. Low wall shear stress concentration occurs at both the anterior and posterior aspects of the proximal internal bulb.

  9. Clinical significance of exercise-induced left ventricular wall motion abnormality occurring at a low heart rate

    Energy Technology Data Exchange (ETDEWEB)

    Kimchi, A.; Rozanski, A.; Fletcher, C.; Maddahi, J.; Swan, H.J.; Berman, D.S.

    1987-10-01

    We studied the relationship between the heart rate at the time of onset of exercise-induced wall motion abnormality and the severity of coronary artery disease in 89 patients who underwent exercise equilibrium radionuclide ventriculography as part of their evaluation for coronary artery disease. Segmental wall motion was scored with a five-point system (3 = normal; -1 = dyskinesis); a decrease of one score defined the onset of wall motion abnormality. The onset of wall motion abnormality at less than or equal to 70% of maximal predicted heart rate had 100% predictive accuracy for coronary artery disease and higher sensitivity than the onset of ischemic ST segment depression at similar heart rate during exercise: 36% (25 of 69 patients with coronary disease) vs 19% (13 of 69 patients), p = 0.01. Wall motion abnormality occurring at less than or equal to 70% of maximal predicted heart rate was present in 49% of patients (23 of 47) with critical stenosis (greater than or equal to 90% luminal diameter narrowing), and in only 5% of patients (2 of 42) without such severe stenosis, p less than 0.001. The sensitivity of exercise-induced wall motion abnormality occurring at a low heart rate for the presence of severe coronary artery disease was similar to that of a deterioration in wall motion by more than two scores during exercise (49% vs 53%) or an absolute decrease of greater than or equal to 5% in exercise left ventricular ejection fraction (49% vs 45%).

  10. Effects of the Transient Blood Flow-Wall Interaction on the Wall Stress Distribution in Abdominal Aortic Aneurysm (AAA)

    Science.gov (United States)

    Tang, Rubing; Geindreau, Christian; Lasheras, Juan

    2006-11-01

    Our static finite element analysis (FEA) of both idealized and real clinical models has shown that the maximum diameter and asymmetry have substantial influence on the AAA wall stress distribution. The thrombus inside the AAA was also found to reduce the magnitude of the wall stresses. To achieve a better understanding of the wall stress distribution in real AAAs, a dynamic FEA was also performed. We considered models, both symmetric and non-symmetric, in which the aorta is assumed isotropic with nonlinear material properties. For the limiting case of rigid walls, the evolution of the flow pattern and the wall shear stresses due to fluid flow at different stages of cardiac cycle predicted by our simulations are compared with experimental results obtained in in-vitro models. A good agreement is found between both results. Finally, we have extended the analysis to the physiologically correct case of deformable walls and characterized the transient effects on the wall stresses.

  11. Relation between wall shear stress and carotid artery wall thickening MRI versus CFD

    DEFF Research Database (Denmark)

    Cibis, Merih; Potters, Wouter V.; Selwaness, Mariana

    2016-01-01

    Wall shear stress (WSS), a parameter associated with endothelial function, is calculated by computational fluid dynamics (CFD) or phase-contrast (PC) MRI measurements. Although CFD is common in WSS (WSSCFD) calculations, PC-MRI-based WSS (WSSMRI) is more favorable in population studies; since it ...

  12. Oxidative Stress State Is Associated with Left Ventricular Mechanics Changes, Measured by Speckle Tracking in Essential Hypertensive Patients

    OpenAIRE

    Luis Antonio Moreno-Ruíz; David Ibarra-Quevedo; Erika Rodríguez-Martínez; Maldonado, Perla D.; Benito Sarabia-Ortega; José Gustavo Hernández-Martínez; Beda Espinosa-Caleti; Beatriz Mendoza-Pérez; Selva Rivas-Arancibia

    2015-01-01

    The oxidative stress state is characterized by an increase in oxygen reactive species that overwhelms the antioxidant defense; we do not know if these pathological changes are correlated with alterations in left ventricular mechanics. The aim was correlating the oxidative stress state with the left ventricular global longitudinal strain (GLS) and the left ventricular end diastolic pressure (LVEDP). Twenty-five patients with essential hypertension and 25 controls paired by age and gender were ...

  13. Deletion of hypothetical wall teichoic acid ligases in Staphylococcus aureus activates the cell wall stress response.

    Science.gov (United States)

    Dengler, Vanina; Meier, Patricia Stutzmann; Heusser, Ronald; Kupferschmied, Peter; Fazekas, Judit; Friebe, Sarah; Staufer, Sibylle Burger; Majcherczyk, Paul A; Moreillon, Philippe; Berger-Bächi, Brigitte; McCallum, Nadine

    2012-08-01

    The Staphylococcus aureus cell wall stress stimulon (CWSS) is activated by cell envelope-targeting antibiotics or depletion of essential cell wall biosynthesis enzymes. The functionally uncharacterized S. aureus LytR-CpsA-Psr (LCP) proteins, MsrR, SA0908 and SA2103, all belong to the CWSS. Although not essential, deletion of all three LCP proteins severely impairs cell division. We show here that VraSR-dependent CWSS expression was up to 250-fold higher in single, double and triple LCP mutants than in wild type S. aureus in the absence of external stress. The LCP triple mutant was virtually depleted of wall teichoic acids (WTA), which could be restored to different degrees by any of the single LCP proteins. Subinhibitory concentrations of tunicamycin, which inhibits the first WTA synthesis enzyme TarO (TagO), could partially complement the severe growth defect of the LCP triple mutant. Both of the latter findings support a role for S. aureus LCP proteins in late WTA synthesis, as in Bacillus subtilis where LCP proteins were recently proposed to transfer WTA from lipid carriers to the cell wall peptidoglycan. Intrinsic activation of the CWSS upon LCP deletion and the fact that LCP proteins were essential for WTA-loading of the cell wall, highlight their important role(s) in S. aureus cell envelope biogenesis. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  14. Cardiac and arterial elastance and myocardial wall stress in children with pectus excavatum

    Science.gov (United States)

    Akyüz Özkan, Esra; Khosrashahi, Hashem E.; Serin, Halil İbrahim; Metin, Bayram; Kılıç, Mahmut; Geçit, U. Aliye

    2016-01-01

    OBJECTIVES Pectus excavatum (PE) is one of the most common skeletal deformities of childhood. The study was undertaken to assess cardiac functions in children with PE. METHODS Echocardiography was performed on 32 children with PE and 40 age-matched healthy controls. The following parameters were monitored: meridional left ventricular (LV) wall stress (WSM), arterial elastance (Ea), LV elastance at end-systole derived by single beat (Ees(sb)), LV circumferential end-systolic wall stress (ESWSc), midwall shortening fraction (SFmid), predicted midwall fiber shortening for a measured fiber stress (midwall VCFc), myocardial fiber stress (MFS), LV end-systolic dimension (LVES), LV end-diastolic dimension (LVED) and end-systolic blood pressure (Pes), LV wall thickness at end-systole (hes). To assess the severity of PE, Haller index (HI) was calculated by computed tomography of the thorax. RESULTS SFmid, ESWSc, midwall VCFc and MFS were lower in PE children than in controls. The degree to which the parameters SFmid, ESWSc, midwall VCFc and MFS were altered in PE children was 14.9, 27.5, 20.3 and 20.3%, respectively. The minimum HI value of children with PE was 2.00, the maximum value was 4.93 and the arithmetic mean was 2.62 ± 0.56. Of the 32 children, 14 (43.75%) demonstrated mild deformity, 15 (46.88%) showed moderate and only 3 (9.37%) had severe deformity. In children with PE, there was no statistically significant correlation between the cardiac data (ESWSc, midwall VCFc, MFS, Ea, Ees(sb), LVES, LVED, Pes, hes) and HI. CONCLUSION We found ESWSc, MFS, midwall VCFc and SFmid to be lower in children with PE than in controls. We concluded that the myocardial contractility and afterload is affected in children with PE. PMID:26993478

  15. Vascular wall stress during intravascular optical coherence tomography imaging

    Science.gov (United States)

    Sun, Cuiru; Yang, Victor

    2015-03-01

    Biomechanical properties of arterial wall is crucial for understanding the changes in the cardiovascular system. Catheters are used during intravascular optical coherence tomography (IVOCT) imaging. The presence of a catheter alters the flow field, pressure distribution and frictional resistance to flow in an artery. In this paper, we first study the transmural stress distribution of the catheterized vessel. COMSOL (COMSOL 4.4) was used to simulate the blood flow induced deformation in a catheterized vessel. Blood is modeled as an incompressible Newtonian fluid. Stress distribution from an three-layer vascular model with an eccentric catheter are simulated, which provides a general idea about the distribution of the displacement and the stress. Optical coherence elastography techniques were then applied to porcine carotid artery samples to look at the deformation status of the vascular wall during saline or water injection. Preliminary simulation results show nonuniform stress distribution in the circumferential direction of the eccentrically catheterized vascular model. Three strain rate methods were tested for intravascular OCE application. The tissue Doppler method has the potential to be further developed to image the vascular wall biomechnical properties in vivo. Although results in this study are not validated quantitatively, the experiments and methods may be valuable for intravascular OCE studies, which may provide important information for cardiovascular disease prevention, diagnosis and treatment.

  16. Right ventricular free-wall longitudinal speckle tracking strain in patients with pulmonary arterial hypertension under specific treatment.

    Science.gov (United States)

    Kemal, Hatice S; Kayikcioglu, Meral; Kultursay, Hakan; Vuran, Ozcan; Nalbantgil, Sanem; Mogulkoc, Nesrin; Can, Levent

    2017-04-01

    Right ventricular (RV) dysfunction is a major determinant of outcomes in patients with pulmonary arterial hypertension (PAH), although the optimal measure of RV function is poorly defined. We evaluated the utility of RV free-wall speckle tracking strain as an assessment tool for RV function in patients with PAH who are already under specific treatment compared with conventional echocardiographic parameters and investigated the relationship of RV free-wall strain with clinical hemodynamic parameters of RV performance. Right ventricular free-wall strain was evaluated in 92 patients (Group-1 and Group-4 pulmonary hypertension) who were on PAH-specific treatment for at least 3 months. Right atrial (RA) area, RV FAC, TAPSE, tricuspid S, functional class, 6-minute walking distance, and NT-proBNP were studied. The mean duration of follow-up was 222±133 days. All patients were under PAH-specific treatment, and mean RV free-wall strain was -13.16±6.3%. RV free-wall strain correlated well with functional class (r=.312, P=.01), NT-proBNP (r=.423, P=.0001), RA area (r=.427, P=.0001), FAC (r=-.637, P=.0001), TAPSE (r=-.524, P=.0001), tricuspid S (r=-.450, P=.0001), 6-minute walking distance (r=-.333, P=.002). RV free-wall strain significantly correlated with all follow-up adverse events, death, and clinical right heart failure (RHF) (P=.04, P=.03, P=.02, respectively). According to the receiver operator characteristic analysis, the cutoff value for RV free-wall strain for the development of clinical RHF was -12.5% (sensitivity: 71%, specificity: 67%) and for all cardiovascular adverse events (death included) was -12.5% (sensitivity: 54%, specificity: 64%). Assessment of RV free-wall strain is a feasible, easy-to-perform method and may be used as a predictor of RHF, clinical deterioration, and mortality in patients already under PAH-specific treatment. © 2017, Wiley Periodicals, Inc.

  17. Clinical impact of ' in-treatment' wall motion abnormalities in hypertensive patients with left ventricular hypertrophy: the LIFE study

    DEFF Research Database (Denmark)

    Cicala, S.; Simone, G. de; Wachtell, K.

    2008-01-01

    In hypertensive patients with LVH and no history of cardiovascular disease, ' in- treatment' left ventricular wall motion abnormalities are associated with increased likelihood of subsequent cardiovascular events independent of age, gender, blood pressure lowering, treatment modality, and in- treatment left......, however, never been investigated. We examined whether 'in- treatment' wall motion abnormalities predicted outcome in the Losartan Intervention For Endpoint ( LIFE) reduction in hypertension echocardiographic substudy. Methods We studied 749 patients without coronary artery disease, myocardial infarction...... to analyze the primary composite endpoint of cardiovascular death, MI, or stroke and, separately, for fatal and nonfatal MI and hospitalized heart failure. Results During a mean follow-up of 4.8 years, an event was recorded in 67 ( 9%) patients. In Cox models after adjusting for age, gender, treatment, blood...

  18. Survival after Left Ventricular Free Wall Rupture in an Elderly Woman with Acute Myocardial Infarction Treated Only Medically

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Roa-Castro

    2012-01-01

    Full Text Available Pseudoaneurysm of the left ventricle is rare and may occur as a result of transmural myocardial infarction. The course of rupture after acute myocardial infarction varies from a catastrophic event, with an acute tear leading to immediate death (acute rupture, or slow and incomplete tear leading to a late rupture (subacute rupture. Incomplete rupture may occur when the thrombus and haematoma together with the pericardium seal the rupture of the left ventricle and may develop into a pseudoaneurysm. Early diagnosis and treatment is essential in this condition. Two-dimensional color Doppler echocardiography is the first-choice method for most patients with suspected left ventricular pseudoaneurysm (LVP and suggests left ventricular rupture in 85% to 90% of patients. We report the case of an 87-year-old woman presenting with symptoms and findings of myocardial infarction and left ventricular free wall rupture with a pseudoaneurysm formation diagnosed by echocardiography and confirmed on CT, MRI, and NM. She received only intense medical treatment, because she refused surgery with a favorable outcome. After 24-month followup, she is in NYHA functional class II. The survival of this patient is due to the contained pseudoaneurysm by dense pericardial adhesions, related to her previous coronary bypass surgery.

  19. Favorable effects of orally administered digoxin on left heart size and ventricular wall motion in patients with previous myocardial infarction.

    Science.gov (United States)

    O'Rourke, R A; Henning, H; Theroux, P; Crawford, M H; Ross, J

    1976-04-01

    The effects of maintenance oral digoxin therapy on segmental left ventricular wall motion (wall motion videotracking) and left heart size (radiographic left heart dimension) were evaluated in 14 patients with a prior myocardial infarction but without clinical signs or symptoms of congestive heart failure. The left heart dimension decreased in all six patients with cardiomegaly from an average of 55.0 +/- 1.6 (standard deviation) to 52.2 +/- 2.7 mm/m2 body surface area (P less than 0.01) during digoxin therapy. However, there was no significant change in the eight patients with normal heart size. In the resting state, the average extent of shortening in normal segments increased significantly from 3.1 +/- 0.8 to 4.2 +/- 1.2 mm during digoxin therapy. During submaximal handgrip exercise, the extent of shortening averaged 4.0 +/- 1.3 mm and increased further with digoxin therapy to 5.1 +/- 2.1 mm. The effects of digoxin therapy on the maximal velocity of shortening in normal segments at rest and during handgrip exercise were similar. In all 14 patients, there was a decrease in the number of segments with abnormal wall motion at rest or with handgrip exercise during digoxin therapy. With therapy, the number of abnormal sites decreased from 52 to 35 in the resting state and from 84 to 49 during handgrip exercise. Thus, in patients 6 or more months after transmural myocardial infarction, orally administered digoxin decreases cardiomegaly, increases the extent and maximal velocity of shortening in normal left ventricular segments and often reduces the extent of abnormal wall motion at rest or during isometric exercise.

  20. Effect of elasticity on wall shear stress inside cerebral aneurysm at anterior cerebral artery.

    Science.gov (United States)

    Xu, Lijian; Sugawara, Michiko; Tanaka, Gaku; Ohta, Makoto; Liu, Hao; Yamaguchi, Ryuhei

    2016-05-18

    Many numerical studies have been published with respect to about flow structures around cerebral aneurysm assuming to be rigid. Furthermore, there is little experimental research concerning aneurysm with elastic wall. Wall shear stress in elastic wall comparing with rigid wall should be clarified in experimental approach and verified in CFD. We have experimentally realized elastic aneurysm model accompanying with wall deformation. Wall shear stress was examined for both rigid and elastic aneurysm models in pulsatile flow. Effect of elasticity on wall shear stress inside aneurysm induced at the apex of anterior cerebral artery was experimentally examined by particle image velocimetry in vitro. In order to adjust the wall deformation, the pressure adjustment chamber was specially equipped outside the aneurysm wall. Effect of elasticity on wall shear stress was noticed on the comparison with that of rigidity. Wall elasticity reduced the peak magnitude, the spatial and temporal averaged wall shear stress comparing with those of wall rigidity experimentally. These reductions were endorsed by fluid-structure interaction simulation. Elastic wall comparing with rigid wall would reduce the peak magnitude, the spatial and temporal averaged wall shear stress acting on vascular wall.

  1. Reduced First-Phase Ejection Fraction and Sustained Myocardial Wall Stress in Hypertensive Patients With Diastolic Dysfunction: A Manifestation of Impaired Shortening Deactivation That Links Systolic to Diastolic Dysfunction and Preserves Systolic Ejection Fraction.

    Science.gov (United States)

    Gu, Haotian; Li, Ye; Fok, Henry; Simpson, John; Kentish, Jonathan C; Shah, Ajay M; Chowienczyk, Philip J

    2017-04-01

    Impaired shortening deactivation of cardiac myocytes could sustain myocardial contraction, preserving ejection fraction at the expense of diastolic dysfunction. We examined the relationship between first-phase ejection fraction (EF1), the fraction of left ventricular volume ejected from the start of systole to the time of the first peak in left ventricular pressure (corresponding to the time of maximal ventricular shortening) to the duration of myocardial contraction and diastolic function in patients with hypertension (n=163), and varying degrees of diastolic dysfunction. Left ventricular systolic pressure was estimated by carotid tonometry; time-resolved left ventricular cavity and wall volume were obtained by echocardiography with speckle wall tracking. Measurements were repeated after nitroglycerin, a drug known to influence ventricular dynamics, in a subsample (n=18) of patients. EF1 and time of onset of ventricular relaxation (as determined from the temporal pattern of myocardial wall stress) were independently correlated with diastolic relaxation as measured by tissue Doppler early diastolic mitral annular velocity (E', standardized regression coefficients 0.48 and -0.34 for EF1 and time of onset of ventricular relaxation, respectively, each Pratio of transmitral Doppler early filling velocity (E) to E' (E/E', regression coefficients -0.34 and 0.34, respectively, each Pexpense of impaired diastolic function. © 2017 The Authors.

  2. Determination of left ventricular mass and circumferential wall thickness by three-dimensional reconstruction: in vitro validation of a new method that uses a multiplane transesophageal transducer.

    Science.gov (United States)

    Kühl, H P; Franke, A; Frielingsdorf, J; Flaskamp, C; Krebs, W; Flachskampf, F A; Hanrath, P

    1997-03-01

    Elevated left ventricular mass and increased wall thickness have important prognostic implications in clinical medicine. However, these parameters have been incompletely characterized by one- and two-dimensional echocardiography. Therefore this study was performed to validate in vitro measurement of left ventricular mass and circumferential wall thickness with a multiplane transesophageal transducer and three-dimensional reconstruction. Results for mass measurements were also compared with a standard method for the determination of left ventricular mass, the Penn convention. Fourteen necropsied left ventricles were scanned in a water bath by a volume-rendering, three-dimensional reconstruction system. There was an excellent correlation and high agreement for determination of three-dimensional left ventricular mass (r = 0.98; standard error of the estimate [SEE] = 9.6 gm; y = 1.02x + 0.46) and wall thickness (r = 0.93; SEE = 1.4 mm; y = 0.95x + 1.64) compared with anatomic measurements. Left ventricular mass by a simulated Penn convention revealed a lower correlation and larger error compared with three-dimensional measurements (r = 0.72; SEE = 42.8 gm; y = 1.01x + 9.61). Therefore determination of left ventricular mass by three-dimensional reconstruction was validated in vitro and was superior to one-dimensional echocardiographic methods.

  3. Left ventricular performance, regional blood flow, wall motion, and lactate metabolism during transluminal angioplasty

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); W. Wijns (William); M.J.B.M. van den Brand (Marcel); S. Meij (Simon); J.C.H. Schuurbiers (Johan); P.W. Hugenholtz; R.W. Brower (Ronald); C.J. Slager (Cornelis)

    1984-01-01

    textabstractThe response of left ventricular function, coronary blood flow, and myocardial lactate metabolism during percutaneous transluminal coronary angioplasty (PTCA) was studied in a series of patients undergoing the procedure. From four to six balloon inflation procedures per patient were

  4. 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

  5. Wall morphology, blood flow and wall shear stress: MR findings in patients with peripheral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Galizia, Mauricio S.; Barker, Alex; Collins, Jeremy; Carr, James [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Liao, Yihua [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); McDermott, Mary M. [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); Northwestern University' s Feinberg School of Medicine, Department of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2014-04-15

    To investigate the influence of atherosclerotic plaques on femoral haemodynamics assessed by two-dimensional (2D) phase-contrast (PC) magnetic resonance imaging (MRI) with three-directional velocity encoding. During 1 year, patients with peripheral artery disease and an ankle brachial index <1.00 were enrolled. After institutional review board approval and written informed consent, 44 patients (age, 70 ± 12 years) underwent common femoral artery MRI. Patients with contra-indications for MRI were excluded. Sequences included 2D time-of-flight, proton-density, T1-weighted and T2-weighted MRI. Electrocardiogram (ECG)-gated 2D PC-MRI with 3D velocity encoding was acquired. A radiologist classified images in five categories. Blood flow, velocity and wall shear stress (WSS) along the vessel circumference were quantified from the PC-MRI data. The acquired images were of good quality for interpretation. There were no image quality problems related to poor ECG-gating or slice positioning. Velocities, oscillatory shear stress and total flow were similar between patients with normal arteries and wall thickening/plaque. Patients with plaques demonstrated regionally increased peak systolic WSS and enhanced WSS eccentricity. Combined multi-contrast morphological imaging of the peripheral arterial wall with PC-MRI with three-directional velocity encoding is a feasible technique. Further study is needed to determine whether flow is an appropriate marker for altered endothelial cell function, vascular remodelling and plaque progression. (orig.)

  6. First wall thermal stress analysis for suddenly applied heat fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Dalessandro, J A

    1978-01-01

    The failure criterion for a solid first wall of an inertial confinement reactor is investigated. Analytical expressions for induced thermal stresses in a plate are given. Two materials have been chosen for this investigation: grade H-451 graphite and chemically vapor deposited (CVD) ..beta..-silicon carbide. Structural failure can be related to either the maximum compressive stress produced on the surface or the maximum tensile stress developed in the interior of the plate; however, it is shown that compressive failure would predominate. A basis for the choice of the thermal shock figure of merit, k(1 - ..nu..) sigma/E ..cap alpha.. kappa/sup 1/2/, is identified. The result is that graphite and silicon carbide rank comparably.

  7. 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

  8. Reduced Sodium Current in the Lateral Ventricular Wall Induces Inferolateral J-Waves.

    Science.gov (United States)

    Meijborg, Veronique M F; Potse, Mark; Conrath, Chantal E; Belterman, Charly N W; De Bakker, Jacques M T; Coronel, Ruben

    2016-01-01

    J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent) responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa), increasing transient outward current conductivity (Gto), or cellular uncoupling in three predefined ventricular regions (lateral, anterior, or septal). Two pig hearts were Langendorff-perfused with selective perfusion with a sodium channel blocker of lateral or anterior/septal regions. Volume-conducted pseudo-electrocardiograms (ECG) were recorded to detect the presence of J-waves. Epicardial unipolar electrograms were simultaneously recorded to obtain activation times (AT). Simulation data showed that conduction slowing, caused by reduced sodium current, in lateral, but not in other regions induced inferolateral J-waves. An increase in transient outward potassium current or cellular uncoupling in the lateral zone elicited slight J-point elevations which did not meet J-wave criteria. Additional conduction slowing in the entire heart attenuated J-waves and J-point elevations on the ECG, because of masking by the QRS. Experimental data confirmed that conduction slowing attributed to sodium channel blockade in the left lateral but not in the anterior/septal ventricular region induced inferolateral J-waves. J-waves coincided with the delayed activation. Reduced sodium current in the left lateral ventricular myocardium can cause inferolateral J-waves on the ECG.

  9. Reduced sodium current in the lateral ventricular wall induces inferolateral J-waves

    Directory of Open Access Journals (Sweden)

    Veronique Marlinde Frederica Meijborg

    2016-08-01

    Full Text Available Background: J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. Methods: Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa, increasing transient outward current conductivity (Gto or cellular uncoupling in three predefined ventricular regions (lateral, anterior or septal. Two pig hearts were Langendorff-perfused with selective perfusion with a sodium channel blocker of lateral or anterior/septal regions. Volume-conducted pseudo-electrocardiograms (ECG were recorded to detect the presence of J-waves. Epicardial unipolar electrograms were simultaneously recorded to obtain activation times (AT.Results: Simulation data showed that conduction slowing, caused by reduced sodium current, in lateral, but not in other regions induced inferolateral J-waves. An increase in transient outward potassium current or cellular uncoupling in the lateral zone elicited slight J-point elevations which did not meet J-wave criteria. Additional conduction slowing in the entire heart attenuated J-waves and J-point elevations on the ECG, because of masking by the QRS. Experimental data confirmed that conduction slowing attributed to sodium channel blockade in the left lateral but not in the anterior/septal ventricular region induced inferolateral J-waves. J-waves coincided with the delayed activation.Conclusion: Reduced sodium current in the left lateral ventricular myocardium can cause inferolateral J-waves on the ECG.

  10. Stress analysis for wall structure in mobile hot cell design

    Energy Technology Data Exchange (ETDEWEB)

    Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  11. Comparative study of diastolic filling under varying left ventricular wall stiffness

    Science.gov (United States)

    Mekala, Pritam; Santhanakrishnan, Arvind

    2014-11-01

    Pathological remodeling of the human cardiac left ventricle (LV) is observed in hypertensive heart failure as a result of pressure overload. Myocardial stiffening occurs in these patients prior to chronic maladaptive changes, resulting in increased LV wall stiffness. The goal of this study was to investigate the change in intraventricular filling fluid dynamics inside a physical model of the LV as a function of wall stiffness. Three LV models of varying wall stiffness were incorporated into an in vitro flow circuit driven by a programmable piston pump. Windkessel elements were used to tune the inflow and systemic pressure in the model with least stiffness to match healthy conditions. Models with stiffer walls were comparatively tested maintaining circuit compliance, resistance and pump amplitude constant. 2D phase-locked PIV measurements along the central plane showed that with increase in wall stiffness, the peak velocity and cardiac output inside the LV decreased. Further, inflow vortex ring propagation toward the LV apex was reduced with increasing stiffness. The above findings indicate the importance of considering LV wall relaxation characteristics in pathological studies of filling fluid dynamics.

  12. The association between right ventricular free wall strain and exercise capacity for health check-up subjects.

    Directory of Open Access Journals (Sweden)

    Wei-Ting Chang

    Full Text Available Right ventricular (RV function has been found to be a major factor of exercise capacity in patients with heart failure. However, the role of RV function in exercise capacity in healthy subjects has not been well studied. This study aims to validate the role of RV strain derived from speckle tracking echocardiography for exercise capacity for health check-up subjects.This study prospectively recruited subjects from a routine health examination. All of them were symptom free. RV function represented by RV strain was derived from speckle tracking echocardiography in addition to traditional echocardiography parameters. Functional capacity was determined by a symptom limited treadmill exercise test with the Bruce protocol.Among 164 recruited subjects (age 52.2 ±9.2 years, 66.4% male, 32 subjects represented impaired functional capacity (MET<8, which was significantly correlated with age, left ventricular mass index, left ventricular filling pressure (E/e', global longitudinal strain of the left ventricle (LVGLS (-16.0±2.5% vs. -18.9±3.8%, p < 0.001 and RV free wall strain (RVLS_FW (-17.0±4.9% vs. -21.9±3.2%, p <0.001. After multivariate logistic regression, RVS_FW was an independent predictor for impaired functional capacity (OR 1.62, CI 1.32-1.98; p <0.001.In conclusion, RV strain is independently associated with exercise capacity for health check-up subjects. RV function is an important factor for functional capacity.

  13. Clinical utility of a multigated modified anterior projection in the detection of left ventricular inferior and apical wall motion abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Polak, J.F.; Bianco, J.A.; Kemper, A.J.; Tow, D.E.

    1982-04-01

    Recent evidence indicates that the left anterior oblique projection (LAO) multigated radionuclide ventriculogram (RVG) underestimates presence and extent of apical and inferior left ventricular (LV) wall motion abnormalities. We investigated, prospectively, the sensitivity and specificity of a modified anterior projection (MAP), which incorporates cephalad tilting. Thirty-three consecutive patients undergoing cardiac catheterization suspected to have coronary artery disease were studied with RVG, using both the MAP and LAO views. LAO views were analyzed using the ejection fraction image (REFI), and the regional ejection fraction (REF) of the inferoapical region. The MAP studies were analyzed using stroke volume image (SVI) to evaluate apical and inferior LV regions. Results were as follows: (Formula: see text), Both intraobserver and interobserver variabilities were comparable to those of conventional angiographic studies used in detection of apical and inferior asynergy. It is concluded that the multigated MAP offers additional information about abnormalities of the LV inferior and apical regions.

  14. Local wall shear stress measurements with a thin plate submerged in the sublayer in wall turbulent flows

    Science.gov (United States)

    Hua, Dan; Suzuki, Hiroki; Mochizuki, Shinsuke

    2017-09-01

    A local wall shear stress measurement technique has been developed using a thin plate, referred to as a sublayer plate which is attached to the wall in the sublayer of a near-wall turbulent flow. The pressure difference between the leading and trailing edges of the plate is correlated to the known wall shear stress obtained in the fully developed turbulent channel flow. The universal calibration curve can be well represented in dimensionless form, and the sensitivity of the proposed method is as high as that of the sublayer fence, even if the sublayer fence is enveloped by the linear sublayer. The results of additional experiments prove that the sublayer plate has fairly good angular resolution in detecting the direction of the local wall shear stress vector.

  15. Value of transient dilation of the left ventricular cavity on stress thallium scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Hiroki; Shiga, Kouji; Umamoto, Ikuo (Kyoto Prefectural Univ. of Medicine (Japan)) (and others)

    1991-02-01

    This study was undertaken to evaluate the value of transient dilation of the left ventricular cavity on stress thallium scintigraphy in 80 patients with ischemic heart disease (IHD) and 50 with hypertrophic cardiomyopathy (HCM). Twenty persons without either coronary artery stenosis or heart disease were served as controls. Areas surrounded by maximum count points on the line of each 10deg on the short axis slice through the mid-cavity of the left ventricle were obtained at 10 minutes and at 3 hours after exercise. Transient dilation index (TDI) was obtained by dividing the area on early image by that on delayed image. TDI was significantly higher in patients with two or three vessel disease in the IHD group than the control group. High TDI was observed in 8% for one vessel disease, 40% for two vessel disease, and 80% for three vessel disease, contributing to the detection of multivessel IHD. In the HCM group of 80 patients, 24 (48%) had high TDI which was frequently associated with a history of chest pain and positive ECG findings at exercise. When these 24 HCM patients underwent exercise blood pool scintiscanning, left ventricular enddiastolic volume was similar before and at 10 minutes after exercise. These findings suggest that transient dilation of the left ventricular cavity after exercise may reflect subendocardial ischemia in both IHD and HCM. TDI would become a useful indicator for transient dilation of the left ventricular cavity. (N.K.).

  16. Wall shear stress distributions on stented patent ductus arteriosus

    Science.gov (United States)

    Kori, Mohamad Ikhwan; Jamalruhanordin, Fara Lyana; Taib, Ishkrizat; Mohammed, Akmal Nizam; Abdullah, Mohammad Kamil; Ariffin, Ahmad Mubarak Tajul; Osman, Kahar

    2017-04-01

    A formation of thrombosis due to hemodynamic conditions after the implantation of stent in patent ductus arteriosus (PDA) will derived the development of re-stenosis. The phenomenon of thrombosis formation is significantly related to the distribution of wall shear stress (WSS) on the arterial wall. Thus, the aims of this study is to investigate the distribution of WSS on the arterial wall after the insertion of stent. Three dimensional model of patent ductus arteriosus inserted with different types of commercial stent are modelled. Computational modelling is used to calculate the distributions of WSS on the arterial stented PDA. The hemodynamic parameters such as high WSS and WSSlow are considered in this study. The result shows that the stented PDA with Type III stent has better hemodynamic performance as compared to others stent. This model has the lowest distributions of WSSlow and also the WSS value more than 20 dyne/cm2. From the observed, the stented PDA with stent Type II showed the highest distributions area of WSS more than 20 dyne/cm2. This situation revealed that the high possibility of atherosclerosis to be developed. However, the highest distribution of WSSlow for stented PDA with stent Type II indicated that high possibility of thrombosis to be formed. In conclusion, the stented PDA model calculated with the lowest distributions of WSSlow and WSS value more than 20dyne/cm2 are considered to be performed well in stent hemodynamic performance as compared to other stents.

  17. Factors influencing left ventricular structure and stress-corrected systolic function in men and women with asymptomatic aortic valve stenosis (a SEAS Substudy)

    DEFF Research Database (Denmark)

    Cramariuc, D.; Rieck, A.E.; Staal, E.M.

    2008-01-01

    To identify determinants of left ventricular (LV) structure and stress-corrected systolic function in men and women with asymptomatic aortic stenosis (AS), Doppler echocardiography was performed at baseline in 1,046 men and 674 women 28 to 86 years of age (mean 67 +/- 10) recruited in the Simvast......To identify determinants of left ventricular (LV) structure and stress-corrected systolic function in men and women with asymptomatic aortic stenosis (AS), Doppler echocardiography was performed at baseline in 1,046 men and 674 women 28 to 86 years of age (mean 67 +/- 10) recruited.......05). In logistic regression analyses, LV hypertrophy was independently associated with male gender, severity of AS, hypertension, higher systolic blood pressure, and lower stress-corrected midwall shortening (scMWS) or stress-corrected fractional shortening (scFS; all p values ... mass, relative wall thickness, aortic regurgitation, hypertension, and end-systolic stress (R(2) = 0.23 and 0.59, respectively, p major determinants of LV hypertrophy in patients with asymptomatic AS are male gender, severity of AS, and concomitant hypertension. Women have...

  18. 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.

  19. Log-layer mismatch and modeling of the fluctuating wall stress in wall-modeled large-eddy simulations

    Science.gov (United States)

    Yang, Xiang I. A.; Park, George Ilhwan; Moin, Parviz

    2017-10-01

    Log-layer mismatch refers to a chronic problem found in wall-modeled large-eddy simulation (WMLES) or detached-eddy simulation, where the modeled wall-shear stress deviates from the true one by approximately 15 % . Many efforts have been made to resolve this mismatch. The often-used fixes, which are generally ad hoc, include modifying subgrid-scale stress models, adding a stochastic forcing, and moving the LES-wall-model matching location away from the wall. An analysis motivated by the integral wall-model formalism suggests that log-layer mismatch is resolved by the built-in physics-based temporal filtering. In this work we investigate in detail the effects of local filtering on log-layer mismatch. We show that both local temporal filtering and local wall-parallel filtering resolve log-layer mismatch without moving the LES-wall-model matching location away from the wall. Additionally, we look into the momentum balance in the near-wall region to provide an alternative explanation of how LLM occurs, which does not necessarily rely on the numerical-error argument. While filtering resolves log-layer mismatch, the quality of the wall-shear stress fluctuations predicted by WMLES does not improve with our remedy. The wall-shear stress fluctuations are highly underpredicted due to the implied use of LES filtering. However, good agreement can be found when the WMLES data are compared to the direct numerical simulation data filtered at the corresponding WMLES resolutions.

  20. Right ventricular relative wall thickness as a predictor of outcomes and of right ventricular reverse remodeling for patients with pulmonary hypertension.

    Science.gov (United States)

    Sano, Hiroyuki; Tanaka, Hidekazu; Motoji, Yoshiki; Fukuda, Yuko; Mochizuki, Yasuhide; Hatani, Yutaka; Matsuzoe, Hiroki; Hatazawa, Keiko; Shimoura, Hiroyuki; Ooka, Junichi; Ryo-Koriyama, Keiko; Nakayama, Kazuhiko; Matsumoto, Kensuke; Emoto, Noriaki; Hirata, Ken-Ichi

    2017-03-01

    Mid-term right ventricular (RV) reverse remodeling after treatment in patients with pulmonary hypertension (PH) is associated with long-term outcome as well as baseline RV remodeling. However, baseline factors influencing mid-term RV reverse remodeling after treatment and its prognostic capability remain unclear. We studied 54 PH patients. Mid-term RV remodeling was assessed in terms of the RV area, which was traced planimetrically at the end-systole (RVESA). RV reverse remodeling was defined as a relative decrease in the RVESA of at least 15% at 10.2 ± 9.4 months after treatment. Long-term follow-up was 5 years. Adverse events occurred in ten patients (19%) and mid-term RV reverse remodeling after treatment was observed in 37 (69%). Patients with mid-term RV reverse remodeling had more favorable long-term outcomes than those without (log-rank: p = 0.01). Multivariate logistic regression analysis showed that RV relative wall thickness (RV-RWT), as calculated as RV free-wall thickness/RV basal linear dimension at end-diastole, was an independent predictor of mid-term RV reverse remodeling (OR 1.334; 95% CI, 1.039-1.713; p = 0.03). Moreover, patients with RV-RWT ≥0.21 showed better long-term outcomes than did those without (log-rank p = 0.03), while those with RV-RWT ≥0.21 and mid-term RV reverse remodeling had the best long-term outcomes. Patients with RV-RWT <0.21 and without mid-term RV reverse remodeling, on the other hand, had worse long-term outcomes than other sub-groups. In conclusions, RV-RWT could predict mid-term RV reverse remodeling after treatment in PH patients, and was associated with long-term outcomes. Our finding may have clinical implications for better management of PH patients.

  1. Shear-stress and wall-stress regulation of vascular remodeling after balloon angioplasty: effect of matrix metalloproteinase inhibition

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); J. Kloet (Jeroen); J.A.F. Oomen; J.C.H. Schuurbiers (Johan); B.J. de Smet; M.J. Post (Mark); D.P.V. de Kleijn (Dominique); G. Pasterkamp (Gerard); R. Krams (Rob); C. Borst (Cornelius); J.J. Wentzel (Jolanda); I. Andhyiswara (Ivan)

    2001-01-01

    textabstractBACKGROUND: Constrictive vascular remodeling (VR) is the most significant component of restenosis after balloon angioplasty (PTA). Whereas in physiological conditions VR is associated with normalization of shear stress (SS) and wall stress (WS), after PTA

  2. Understanding the fluid mechanics behind transverse wall shear stress.

    Science.gov (United States)

    Mohamied, Yumnah; Sherwin, Spencer J; Weinberg, Peter D

    2017-01-04

    The patchy distribution of atherosclerosis within arteries is widely attributed to local variation in haemodynamic wall shear stress (WSS). A recently-introduced metric, the transverse wall shear stress (transWSS), which is the average over the cardiac cycle of WSS components perpendicular to the temporal mean WSS vector, correlates particularly well with the pattern of lesions around aortic branch ostia. Here we use numerical methods to investigate the nature of the arterial flows captured by transWSS and the sensitivity of transWSS to inflow waveform and aortic geometry. TransWSS developed chiefly in the acceleration, peak systolic and deceleration phases of the cardiac cycle; the reverse flow phase was too short, and WSS in diastole was too low, for these periods to have a significant influence. Most of the spatial variation in transWSS arose from variation in the angle by which instantaneous WSS vectors deviated from the mean WSS vector rather than from variation in the magnitude of the vectors. The pattern of transWSS was insensitive to inflow waveform; only unphysiologically high Womersley numbers produced substantial changes. However, transWSS was sensitive to changes in geometry. The curvature of the arch and proximal descending aorta were responsible for the principal features, the non-planar nature of the aorta produced asymmetries in the location and position of streaks of high transWSS, and taper determined the persistence of the streaks down the aorta. These results reflect the importance of the fluctuating strength of Dean vortices in generating transWSS. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Clinical Stress Echocardiography

    NARCIS (Netherlands)

    S.E. Karagiannis

    2007-01-01

    textabstractTwo-dimensional echocardiography is a commonly used non-invasive method for the assessment of left ventricular function. It provides precise information on both global and segmental myocardial function by displaying endocardial motion and wall thickening. Dobutamine stress

  4. Stress-induced alteration of left ventricular eccentricity: An additional marker of multivessel CAD.

    Science.gov (United States)

    Gimelli, Alessia; Liga, Riccardo; Giorgetti, Assuero; Casagranda, Mirta; Marzullo, Paolo

    2017-03-28

    Abnormal left ventricular (LV) eccentricity index (EI) is a marker of adverse cardiac remodeling. However, the interaction between stress-induced alterations of EI and major cardiac parameters has not been explored. We sought to evaluate the relationship between LV EI and coronary artery disease (CAD) burden in patients submitted to myocardial perfusion imaging (MPI). Three-hundred and forty-three patients underwent MPI and coronary angiography. LV ejection fraction (EF) and EI were computed from gated stress images as measures of stress-induced functional impairment. One-hundred and thirty-six (40%), 122 (35%), and 85 (25%) patients had normal coronary arteries, single-vessel CAD, and multivessel CAD, respectively. Post-stress EI was lower in patients with multivessel CAD than in those with normal coronary arteries and single-vessel CAD (P = 0.001). This relationship was confirmed only in patients undergoing exercise stress test, where a lower post-stress EI predicted the presence of multivessel CAD (P = 0.039). Post-stress alterations of LV EI on MPI may unmask the presence of multivessel CAD.

  5. Oxidative Stress Biomarkers and Left Ventricular Hypertrophy in Children with Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Dorota Drożdż

    2016-01-01

    Full Text Available Cardiovascular diseases remain the most frequent cause of morbidity and mortality in patients with chronic kidney disease (CKD. The aim of the study was to assess the association between oxidative stress biomarkers and cardiovascular risk factors and left ventricular hypertrophy in children with CKD. Material and Methods. The studied group consisted of 65 patients aged 1.4–18.6 (mean 11.2 years with stages 1 to 5 CKD. Serum oxidized low-density lipoprotein (oxLDL, protein carbonyl group, creatinine, cystatin C, albumin, lipids, high-sensitivity C-reactive protein, intercellular adhesion molecule-1, insulin, plasma renin activity, and aldosterone levels were measured. Patients were divided into groups depending on CKD stage. Anthropometric measurements, ambulatory blood pressure (BP measurements, and echocardiography with left ventricular mass (LVM calculation were performed. Results. Serum oxLDL strongly correlated with creatinine (R=0.246; p=0.048, cystatin C (R=0.346; p=0.006, total cholesterol (R=0.500; p<0.001, triglycerides (R=0.524; p<0.001, low-density lipoprotein concentrations (R=0.456; p<0.001, and 24 hour BP values of systolic (R=0.492; p=0.002, diastolic (R=0.515; p<0.001, and mean arterial pressure (R=0.537; p<0.001. A significant correlation between oxLDL levels and LVM z-scores (R=0.299; p=0.016 was found. Conclusions. Hypertension and dyslipidemia correlated with lipid oxidation in children with CKD. oxLDLs seem to be valuable markers of oxidative stress in CKD patients, correlating with left ventricular hypertrophy.

  6. Simultaneous measurement of left and right ventricular volumes and ejection fraction during dobutamine stress cardiovascular magnetic resonance.

    Science.gov (United States)

    Mandapaka, Sangeeta; Hamilton, Craig A; Morgan, Timothy M; Hundley, William Gregory

    2011-01-01

    During cardiovascular stress, if right ventricular (RV) stroke volume exceeds left ventricular (LV) stroke volume, then a large volume of blood is displaced into the pulmonary circulation that may precipitate pulmonary edema. We sought to determine the metrics by which cardiovascular magnetic resonance (CMR) could measure simultaneous displacement of RV and LV stroke volumes during dobutamine stress. Thirteen healthy subjects (5 women) aged 53 ± 10 years without medical conditions and taking no medications underwent 2 CMR examinations at 1.5 T separated by 4 to 8 weeks in which RV and LV stroke volumes were determined during intravenous dobutamine and atropine infused to achieve 80% of the maximum predicted heart rate response for age. The RV and LV stroke volumes were highly correlated at each level of stress (rest: r = 0.98, P = 0.007; low stress: r = 0.87, P = 0.001; and peak stress: r = 0.88, P = 0.001), and the mean difference in SV at each level of stress (rest, low stress, and peak stress was 0 to 2 mL on examinations 1 and 2. Simultaneous change in right and left ventricular stroke volumes can be assessed in a highly reproducible manner throughout the course of dobutamine CMR stress administered to achieve 80% of maximum predicted heart rate response for age. This technology may help identify discrepancies in RV and LV stroke volumes during cardiovascular stress that are associated with the development of pulmonary edema.

  7. Beneficial effects of elevating cardiac preload on left-ventricular diastolic function and volume during heat stress

    DEFF Research Database (Denmark)

    Brothers, R M; Pecini, Redi; Dalsgaard, Morten

    2014-01-01

    conditions prior to and during a simulated hemorrhagic challenge. Heat stress did not change indices of diastolic function. Subsequent volume infusion elevated indices of diastolic function, specifically early diastolic mitral annular tissue velocity (E') and early diastolic propagation velocity (E) relative......Volume loading normalizes tolerance to a simulated hemorrhagic challenge in heat-stressed individuals, relative to when these individuals are thermoneutral. The mechanism(s) by which this occurs is unknown. This project tested two unique hypotheses; that is, the elevation of central blood volume...... via volume loading while heat stressed would 1) increase indices of left ventricular diastolic function, and 2) preserve left ventricular end-diastolic volume (LVEDV) during a subsequent simulated hemorrhagic challenge induced by lower-body negative pressure (LBNP). Indices of left ventricular...

  8. A comparison of modelling techniques for computing wall stress in abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    McGloughlin Timothy M

    2007-10-01

    Full Text Available Abstract Background Aneurysms, in particular abdominal aortic aneurysms (AAA, form a significant portion of cardiovascular related deaths. There is much debate as to the most suitable tool for rupture prediction and interventional surgery of AAAs, and currently maximum diameter is used clinically as the determining factor for surgical intervention. Stress analysis techniques, such as finite element analysis (FEA to compute the wall stress in patient-specific AAAs, have been regarded by some authors to be more clinically important than the use of a "one-size-fits-all" maximum diameter criterion, since some small AAAs have been shown to have higher wall stress than larger AAAs and have been known to rupture. Methods A patient-specific AAA was selected from our AAA database and 3D reconstruction was performed. The AAA was then modelled in this study using three different approaches, namely, AAA(SIMP, AAA(MOD and AAA(COMP, with each model examined using linear and non-linear material properties. All models were analysed using the finite element method for wall stress distributions. Results Wall stress results show marked differences in peak wall stress results between the three methods. Peak wall stress was shown to reduce when more realistic parameters were utilised. It was also noted that wall stress was shown to reduce by 59% when modelled using the most accurate non-linear complex approach, compared to the same model without intraluminal thrombus. Conclusion The results here show that using more realistic parameters affect resulting wall stress. The use of simplified computational modelling methods can lead to inaccurate stress distributions. Care should be taken when examining stress results found using simplified techniques, in particular, if the wall stress results are to have clinical importance.

  9. Verapamil induced ventricular hypertrophy in conscious dogs.

    Science.gov (United States)

    French, W J; Garner, D; Adomian, G E; Averill, W; Laks, M M

    1989-08-01

    Verapamil is used clinically in the treatment of various cardiac diseases including hypertrophic cardiomyopathy. Its long term effects on ventricular mass are not well known. In 11 conscious dogs heart rate, aortic and left ventricular pressures, cardiac output, a methoxamine induced stress ventricular function test and left ventriculography were performed. These variables were measured prior to and following a mean 7.2 month infusion of verapamil at 0.005 or 0.01 mg.kg-1.min-1 using a subcutaneously implanted pump. Resting haemodynamic variables and left ventricular ejection fraction [60(SD 6) v 55(6)%] were unchanged between baseline and chronic verapamil studies, but the slope of the methoxamine induced stress ventricular function test decreased from 3.9(0.8) to 2.1 (1.3). After verapamil was discontinued the mean slope of the stress ventricular function test returned to the baseline 4.0(1.7). Total ventricular weight increased 22% from 176.1(17.5) g.m-2 in controls to 215.6(29.5) g.m-2 (p less than 0.01) in the verapamil animals. The right ventricular weight increased 25% from 46(5.9) to 57.6(9.1) g.m-2 (p less than 0.01); the septum weight increased 26% from 42.5(4.1) to 53.7(7.2) g.m-2 (p less than 0.001); and the left ventricular free wall weight increased 19% from 87.4(9.8) to 103.9(15.7) g.m-2 (p less than 0.01). The increase in ventricular weights was not due to fibrosis or oedema since hydroxyproline contents and wet/dry ratios were not increased. In conclusion, a chronic infusion of verapamil in conscious dogs caused no change in resting haemodynamic variables but produced reversible depression of stress ventricular function and biventricular and septal hypertrophy.

  10. Residual Stress Impairs Pump Function After Surgical Ventricular Remodeling: A Finite Element Analysis.

    Science.gov (United States)

    Pantoja, Joe Luis; Zhang, Zhihong; Tartibi, Mehrzad; Sun, Kay; Macmillan, Warrick; Guccione, Julius M; Ge, Liang; Ratcliffe, Mark B

    2015-12-01

    Surgical ventricular restoration (Dor procedure) is generally thought to reduce left ventricular (LV) myofiber stress (FS) but to adversely affect pump function. However, the underlying mechanism is unclear. The goal of this study was to determine the effect of residual stress (RS) on LV FS and pump function after the Dor procedure. Previously described finite element models of the LV based on magnetic resonance imaging data obtained in 5 sheep 16 weeks after anteroapical myocardial infarction were used. Simulated polyethylene terephthalate fiber (Dacron) patches that were elliptical and 25% of the infarct opening area were implanted using a virtual suture technique (VIRTUAL-DOR). In each case, diastole and systole were simulated, and RS, FS, LV volumes, systolic and diastolic function, and pump (Starling) function were calculated. VIRTUAL-DOR was associated with significant RS that was tensile (2.89 ± 1.31 kPa) in the remote myocardium and compressive (234.15 ± 65.53 kPa) in the border zone. VIRTUAL-DOR+RS (compared with VIRTUAL-DOR-NO-RS) was associated with further reduction in regional diastolic and systolic FS, with the greatest change in the border zone (43.5-fold and 7.1-fold, respectively; p < 0.0001). VIRTUAL-DOR+RS was also associated with further reduction in systolic and diastolic volumes (7.9%; p = 0.0606, and 10.6%; p = 0.0630, respectively). The resultant effect was a further reduction in pump function after VIRTUAL-DOR+RS. Residual stress that occurs after the Dor procedure is positive (tensile) in the remote myocardium and negative (compressive) in the border zone and associated with reductions in FS and LV volumes. The resultant effect is a further reduction in LV pump (Starling) function. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. 4D left ventricular resultant wall motion and blood flow assessed by phase-shift velocity mapping at high-field 3T MRI.

    Science.gov (United States)

    Samnøy, Stig F; Cuypers, Jochem; Greve, Gottfried; Larsen, Terje H

    2017-11-01

    Contractility and elasticity of the myocardium are important variables for detecting anomalies that may influence pump function. It is important to assess both wall motion and blood flow to detect regional left ventricular (LV) dysfunction and abnormal flow patterns. This study discusses four-dimensional (4D) phase-contrast magnetic resonance imaging (MRI) for simultaneous quantification and visualization of LV wall motion and blood flow. In thirteen healthy subjects, a three-directional retrospective cardiac triggered phase-shift velocity mapping technique was used to acquire velocity data of the LV throughout the cardiac cycle. All short-axis slices of the LV wall were segmented in six sectors of 60° starting from the anterior hinge point between the right and left ventricles, from base to apex. Velocity data in resultant, radial, circumferential and longitudinal directions were calculated and presented as coloured three-directional vectors. Our findings showed a reduction in maximum wall velocities from base to apex, whereas for the radial and circumferential directions no significant differences were noted (13·1 ± 2·7 and 13·0 ± 2·9 cm s(-1) , respectively. P = 0·9). The longitudinal maximum velocities (21·0 ± 0·6 cm s(-1) ) were significantly higher than the radial and circumferential components (P = 0·002). We found that the inclination angle of the resultant blood flow was changed towards the left ventricular outflow tract during systole. Using this 4D MRI velocity mapping technique, we present an improved method for quantification and visualization of ventricular wall velocities in the radial, circumferential and longitudinal directions, as well as for the intracavity blood flow. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  12. Identifying delayed left ventricular lateral wall activation in patients with non-specific intraventricular conduction delay using coronary venous electroanatomical mapping.

    Science.gov (United States)

    van Stipdonk, A M W; Rad, M Mafi; Luermans, J G L M; Crijns, H J; Prinzen, F W; Vernooy, K

    2016-01-01

    Delayed left ventricular (LV) lateral wall activation is considered the electrical substrate that characterises patients suitable for cardiac resynchronisation therapy (CRT). Although typically associated with left bundle branch block, delayed LV lateral wall activation may also be present in patients with non-specific intraventricular conduction delay (IVCD). We assessed LV lateral wall activation in a cohort of CRT candidates with IVCD using coronary venous electroanatomical mapping, and investigated whether baseline QRS characteristics on the ECG can identify delayed LV lateral wall activation in this group of patients. Twenty-three consecutive CRT candidates with IVCD underwent intra-procedural coronary venous electroanatomical mapping using EnSite NavX. Electrical activation time was measured in milliseconds from QRS onset and expressed as percentage of QRS duration. LV lateral wall activation was considered delayed if maximal activation time measured at the LV lateral wall (LVLW-AT) exceeded 75 % of the QRS duration. QRS morphology, duration, fragmentation, axis deviation, and left anterior/posterior fascicular block were assessed on baseline ECGs. Delayed LV lateral wall activation occurred in 12/23 patients (maximal LVLW-AT = 133 ± 20 ms [83 ± 5 % of QRS duration]). In these patients, the latest activated region was consistently located on the basal lateral wall. QRS duration, and prevalence of QRS fragmentation and left/right axis deviation, and left anterior/posterior fascicular block did not differ between patients with and without delayed LV lateral wall activation. Coronary venous electroanatomical mapping can be used at the time of CRT implantation to determine the presence of delayed LV lateral wall activation in patients with IVCD. QRS characteristics on the ECG seem unable to identify delayed LV lateral wall activation in this subgroup of patients.

  13. End-systolic stress-velocity relation and circumferential fiber velocity shortening for analysing left ventricular function in mice

    Energy Technology Data Exchange (ETDEWEB)

    Fayssoil, A. [Cardiologie, Hopital europeen Georges Pompidou, 20, rue le blanc, Paris (France)], E-mail: fayssoil2000@yahoo.fr; Renault, G. [CNRS UMR 8104, Inserm, U567, Institut Cochin, Universite Paris Descartes, Paris (France); Fougerousse, F. [Genethon, RD, Evry (France)

    2009-08-15

    Traditionally, analysing left ventricular (LV) performance relies on echocardiography by evaluating shortening fraction (SF) in mice. SF is influenced by load conditions. End-systolic stress-velocity (ESSV) relation and circumferential fiber velocity (VcF) shortening are more relevant parameters for evaluating systolic function regardless load conditions particularly in mice's models of heart failure.

  14. [Occupational stress as a factor of left ventricular myocardial remodeling in people with normal arterial pressure].

    Science.gov (United States)

    Sorokin, A V; Prazdnov, A S; Korovina, O V

    2007-01-01

    The authors studied correlations between occupational stress, caused by high tension at work, and disturbances in 24-hour arterial pressure (AP), lipid level, and left ventricular (LM) myocardial remodeling in locomotive engineers with normal AP. Two hundred and five locomotive engineers with NAP (according to 2004 classification by Russian Scientific Society of Cardiologists) aged 20 to 45 years were included in this cross-sectional study; the subjects present a whole sample of the locomotive crew of Chelyabinsk railway station. The control group consisted of III persons working eight fixed working hours a day whose work was not associated with high tension (turners and metalworkers). The examination of the both groups included bifunctional 24-hour AP and ECG monitoring during the subjects'days off, Echo CG, measurement of blood lipids, and measurement of table salt sensitivity threshold. Also evaluated were the prevalence of horizontal and vertical family background of arterial hypertension, excessive body weight, hypokinesia, and smoking. The study demonstrated that the prevalence of the chief factors of chronic non-infectious diseases as well as the values of office and 24-hour systolic and diastolic arterial pressure (SAD; DAD) were the same in both groups. At the same time, the locomotive engineers with normal AP had unfavorable hemodynamic AP profile (24-hour SAD index (p = 0.008) was lower indicating insufficient SAD decrease at night; the speed of morning SAD and DAD increase was elevated 1.5 to 2 times; heart rate was higher as well) which can be considered signs of hypersympathicotonia. By comparison with the controls, the locomotive engineers had more pronounced morphofunctional changes in the left ventricular (LV), myocardium; LV mass was greater, and LV myocardial hypertrophy was more frequent in this group (17.9 and 1.8%, respectively). The data demonstrate the contribution of occupational stress-related non-hemodynamic factors to myocardial

  15. Right ventricular relative wall thickness as a predictor of outcomes and of right ventricular reverse remodeling for patients with pulmonary hypertension

    OpenAIRE

    Sano, Hiroyuki; Tanaka, Hidekazu; Motoji, Yoshiki; Fukuda, Yuko; Mochizuki, Yasuhide; Hatani, Yutaka; Matsuzoe, Hiroki; Hatazawa, Keiko; Shimoura, Hiroyuki; Ooka, Junichi; Ryo-Koriyama, Keiko; Nakayama, Kazuhiko; Matsumoto, Kensuke; Emoto, Noriaki; Hirata, Ken-ichi

    2017-01-01

    Mid-term right ventricular (RV) reverse remodeling after treatment in patients with pulmonary hypertension (PH) is associated with long-term outcome as well as baseline RV remodeling. However, baseline factors influencing mid-term RV reverse remodeling after treatment and its prognostic capability remain unclear. We studied 54 PH patients. Mid-term RV remodeling was assessed in terms of the RV area, which was traced planimetrically at the end-systole (RVESA). RV reverse remodeling was defined...

  16. Standard practice for estimating the approximate residual circumferential stress in straight thin-walled tubing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 A qualitative estimate of the residual circumferential stress in thin-walled tubing may be calculated from the change in outside diameter that occurs upon splitting a length of the tubing. This practice assumes a linear stress distribution through the tube wall thickness and will not provide an estimate of local stress distributions such as surface stresses. (Very high local residual stress gradients are common at the surface of metal tubing due to cold drawing, peening, grinding, etc.) The Hatfield and Thirkell formula, as later modified by Sachs and Espey, provides a simple method for calculating the approximate circumferential stress from the change in diameter of straight, thin-walled, metal tubing. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  17. End-systolic wall stress predicts post-discharge heart failure after acute myocardial infarction.

    Science.gov (United States)

    Clerfond, Guillaume; Bière, Loïc; Mateus, Victor; Grall, Sylvain; Willoteaux, Serge; Prunier, Fabrice; Furber, Alain

    2015-05-01

    Compensatory mechanisms activated after myocardial infarction include an increase in systolic wall stress (SWS) and activation of the neurohormonal system. Nevertheless, left ventricular ejection fraction (LVEF) and infarct size are the established primary predictors of outcome after ST-segment elevation myocardial infarction. To assess the relative impact of various cardiac magnetic resonance (CMR) imaging variables, such as infarct size, LVEF and SWS, on pre- and post-discharge heart failure (HF). CMR was performed in a prospective study involving 169 patients with first ST-segment elevation myocardial infarction. Common CMR findings, such as SWS, were computed. Mean SWS was 16.3±5.1×10(3)N·m(-2), and was systematically higher in patients exhibiting either pre- or post-discharge HF (18.9±5.7 and 21.3±7.6×10(3) N·m(-2), respectively). SWS was moderately related to initial infarct size (r=0.405; P <0.001). In total, 28 patients presented with HF during the hospitalization phase and 14 during follow-up, with a median time of event of 93 days (25th-75th percentiles, 29-139.25 days). The univariate predictors of HF were age, LVEF, infarct size, SWS, microvascular obstruction, anterior infarction and heart rate at admission. Multivariable analysis revealed infarct size and age to be the predictors of predischarge HF, while SWS and heart rate at admission predicted post-discharge HF. The greatest SWS quartile provided a negative predictive value of 95.9%. Regardless of LVEF and infarct size, SWS was shown to be an independent predictor of post-discharge HF after ST-segment elevation myocardial infarction. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Effect of tip clearance on wall shear stress of an axial LVAD

    Science.gov (United States)

    Sarath, S.; Vikas, R.

    2017-09-01

    Wall shear stress is a crucial parameter used for blood damage analysis, and typically a value of 400 Pa is set as a limit. Tip clearance is a major factor contributing to hemolysis and pump efficiency. In this study, different tip gap configurations are used to analyse the wall shear stress developed on the blade surface of a constant thickness blade design, and a varying thickness blade design using CFD analysis. It was found that, for a particular geometry, as the clearance gap reduces, flow rate over the high wall shear stress area decreases even though the high wall shear stress span is found to extend. For each design, the optimum clearance gap is iteratively attained, keeping the maximum WSS as a limiting factor. Thus a better pump designs is obtained, whose leakage flow patterns are lower than that of the initial design, hence also leading to higher pump efficiency.

  19. Exercise-mediated changes in conduit artery wall thickness in humans: role of shear stress

    NARCIS (Netherlands)

    Thijssen, D.H.J.; Dawson, E.A.; Munckhof, I.C. van den; Tinken, T.M.; Drijver, E. den; Hopkins, N.; Cable, N.T.; Green, D.J.

    2011-01-01

    Episodic increases in shear stress have been proposed as a mechanism that induces training-induced adaptation in arterial wall remodeling in humans. To address this hypothesis in humans, we examined bilateral brachial artery wall thickness using high-resolution ultrasound in healthy men across an

  20. Effect of Wall Shear Stress Distribution on Manning Coefficient of Smooth Open Rectangular Channel Flows

    OpenAIRE

    BİLGİL, Ahmet

    2003-01-01

    The determination of velocity distribution in open channel flows is crucial in many critical engineering problems such as channel design, calculation of energy losses and sedimentation. In this study, velocity distribution is experimentally investigated in a smooth rectangular open channel. Wall shear stresses are calculated using measured local velocities. Assuming logarithmic velocity distribution along perpendiculars to a wetted perimeter, dimensionless wall shear stresses K(I) =...

  1. Using two soft computing methods to predict wall and bed shear stress in smooth rectangular channels

    Science.gov (United States)

    Khozani, Zohreh Sheikh; Bonakdari, Hossein; Zaji, Amir Hossein

    2017-11-01

    Two soft computing methods were extended in order to predict the mean wall and bed shear stress in open channels. The genetic programming (GP) and Genetic Algorithm Artificial Neural Network (GAA) were investigated to determine the accuracy of these models in estimating wall and bed shear stress. The GP and GAA model results were compared in terms of testing dataset in order to find the best model. In modeling both bed and wall shear stress, the GP model performed better with RMSE of 0.0264 and 0.0185, respectively. Then both proposed models were compared with equations for rectangular open channels, trapezoidal channels and ducts. According to the results, the proposed models performed the best in predicting wall and bed shear stress in smooth rectangular channels. The obtained equation for rectangular channels could estimate values closer to experimental data, but the equations for ducts had poor, inaccurate results in predicting wall and bed shear stress. The equation presented for trapezoidal channels did not have acceptable accuracy in predicting wall and bed shear stress either.

  2. Using two soft computing methods to predict wall and bed shear stress in smooth rectangular channels

    Science.gov (United States)

    Khozani, Zohreh Sheikh; Bonakdari, Hossein; Zaji, Amir Hossein

    2017-03-01

    Two soft computing methods were extended in order to predict the mean wall and bed shear stress in open channels. The genetic programming (GP) and Genetic Algorithm Artificial Neural Network (GAA) were investigated to determine the accuracy of these models in estimating wall and bed shear stress. The GP and GAA model results were compared in terms of testing dataset in order to find the best model. In modeling both bed and wall shear stress, the GP model performed better with RMSE of 0.0264 and 0.0185, respectively. Then both proposed models were compared with equations for rectangular open channels, trapezoidal channels and ducts. According to the results, the proposed models performed the best in predicting wall and bed shear stress in smooth rectangular channels. The obtained equation for rectangular channels could estimate values closer to experimental data, but the equations for ducts had poor, inaccurate results in predicting wall and bed shear stress. The equation presented for trapezoidal channels did not have acceptable accuracy in predicting wall and bed shear stress either.

  3. Control of circumferential wall stress and luminal shear stress within intact vascular segments perfused ex vivo.

    Science.gov (United States)

    El-Kurdi, Mohammed S; Vipperman, Jeffrey S; Vorp, David A

    2008-10-01

    Proportional, integral, and derivative (PID) controllers have proven to be robust in controlling many applications, and remain the most widely used control system architecture. The purpose of this work was to use this architecture for designing and tuning two PID controllers. The first was used to control the physiologic arterial circumferential wall stress (CWS) and the second to control the physiologic arterial shear stress (SS) imposed on intact vascular segments that were implanted into an ex vivo vascular perfusion system (EVPS). In order to most accurately control the stresses imposed onto vascular segments perfused ex vivo, analytical models were derived to calculate the CWS and SS. The mid-vein-wall CWS was calculated using the classical Lame solution for thick-walled cylinders in combination with the intraluminal pressure and outer diameter measurements. Similarly, the SS was calculated using the Hagen-Poiseuille equation in combination with the flow rate and outer diameter measurements. Performance of each controller was assessed by calculating the root mean square of the error (RMSE) between the desired and measured process variables. The performance experiments were repeated ten times (N=10) and an average RMSE was reported for each controller. RMSE standard deviations were calculated to demonstrate the reproducibility of the results. Sterile methods were utilized for making blood gas and temperature measurements in order to maintain physiologic levels within the EVPS. Physiologic blood gases (pH, pO(2), and pCO(2)) and temperature within the EVPS were very stable and controlled manually. Blood gas and temperature levels were recorded hourly for several (N=9) 24 h perfusion experiments. RMSE values for CWS control (0.427+/-0.027 KPa) indicated that the system was able to generate a physiologic CWS wave form within 0.5% error of the peak desired CWS over each cardiac cycle. RMSE values for SS control (0.005+/-0.0007 dynescm(2)) indicated that the system

  4. End-Systolic Elastance and Ventricular-Arterial Coupling Reserve Predict Cardiac Events in Patients with Negative Stress Echocardiography

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    Tonino Bombardini

    2013-01-01

    Full Text Available Background. A maximal negative stress echo identifies a low-risk subset for coronary events. However, the potentially prognostically relevant information on cardiovascular hemodynamics for heart-failure-related events is unsettled. Aim of this study was to assess the prognostic value of stress-induced variation in cardiovascular hemodynamics in patients with negative stress echocardiography. Methods. We enrolled 891 patients (593 males mean age 63±12, ejection fraction 48±17%, with negative (exercise 172, dipyridamole 482, and dobutamine 237 stress echocardiography result. During stress we assessed left ventricular end-systolic elastance index (ELVI, ventricular arterial coupling (VAC indexed by the ratio of the ELVI to arterial elastance index (EaI, systemic vascular resistance (SVR, and pressure-volume area (PVA. Changes from rest to peak stress (reserve were tested as predictors of main outcome measures: combined death and heart failure hospitalization. Results. During a median followup of 19 months (interquartile range 8–36, 50 deaths and 84 hospitalization occurred. Receiver-operating-characteristic curves identified as best predictors ELVI reserve for exercise (AUC = 0.871 and dobutamine (AUC = 0.848 and VAC reserve (AUC = 0.696 for dipyridamole. Conclusions. Patients with negative stress echocardiography may experience an adverse outcome, which can be identified by assessment of ELVI reserve and VAC reserve during stress echo.

  5. Estudo da função ventricular na técnica de plicatura da parede livre do ventrículo esquerdo em cães Left ventricular function after plication of the left ventricular free wall in dogs

    Directory of Open Access Journals (Sweden)

    James Newton Bizetto Meira de Andrade

    2004-06-01

    Full Text Available OBJETIVO: Avaliar os efeitos da técnica na função ventricular esquerda em cães hígidos e com cardiomiopatia dilatada induzida pela doxorrubicina. MÉTODO: De 13 cães, oito receberam doxorrubicina até que a fração de encurtamento (FE fosse menor que 20%. Destes, quatro animais e os cinco não induzidos foram submetidos à plicatura da parede livre do ventrículo esquerdo (PPLVE. Os demais cães não foram operados. Foram avaliados débito cardíaco (DC, pressão arterial, exame físico, eletrocardiografia, sistema "Holter" e ecocardiografia, por 180 dias. RESULTADOS: Houve redução do volume ventricular esquerdo. Os cães induzidos melhoraram após a operação e a fração de ejeção (FEj retornou aos valores normais para a espécie. O DC e a FE aumentaram após a operação. Um cão foi a óbito. Nos cães não operados, a FE diminuiu e foram a óbito em torno de 40 dias após a indução; nos cães não induzidos, esta não se alterou. Houve extra-sístoles ventriculares, que se resolveram espontaneamente. CONCLUSÕES: A PPLVE sem circulação extracorpórea reduz o volume ventricular esquerdo e melhora a função cardíaca dos cães com cardiomiopatia dilatada induzida pela doxorrubicina, demonstrando baixa morbidade e mortalidade tardia.OBJECTIVE: We tested a new surgical technique, the plication of the left ventricular free wall, to reduce left ventricular area and volume and improve left ventricular systolic function, without using a cardiopulmonary bypass. METHODS: Dilated cardiomyopathy was induced in eight dogs by the injection of doxorubicin. Plication of the left ventricular free wall was performed in four dogs with induced cardiomyopathy and in five control dogs. Two dogs not submitted to surgery. The other two dogs died during the induction phase. Cardiac output, 2-dimensional and M-mode echocardiography, arterial blood pressure and electrocardiography were recorded over a 180 days period. Ambulatory electrocardiography

  6. Echocardiography-Derived Left Ventricular Outflow Tract Gradient and Left Ventricular Posterior Wall Thickening Are Associated with Outcomes for Anatomic Repair in Congenitally Corrected Transposition of the Great Arteries.

    Science.gov (United States)

    Moodley, Shreya; Balasubramanian, Sowmya; Tacy, Theresa A; Chan, Frandics; Hanley, Frank L; Punn, Rajesh

    2017-08-01

    Congenitally corrected transposition of the great arteries is a rare form of congenital heart disease. Management is controversial; options include observation, physiologic repair, and anatomic repair. Assessment of morphologic left ventricle preparedness is key in timing anatomic repair. This study's purpose was to review the modalities used to assess the morphologic left ventricle preoperatively and to determine if any echocardiographic variables are associated with outcomes. A retrospective review of patients with congenitally corrected transposition of the great arteries eligible for anatomic repair at Lucile Packard Children's Hospital from 2000 to 2016 was conducted. Inclusion criteria were (1) presurgical echocardiography, magnetic resonance imaging, and cardiac catheterization and (2) clinical follow-up information. Echocardiographic measurements included left ventricular (LV) single-plane Simpson's ejection fraction, LV eccentricity index, LV posterior wall thickening, pulmonary artery band (PAB)/LV outflow tract (LVOT) pressure gradient, and LV and right ventricular strain. Magnetic resonance imaging measurements included LV mass, ejection fraction, eccentricity index, and LV thickening. LV pressure, PAB/LVOT gradient, right ventricular pressure, pulmonary vascular resistance, and Qp/Qs constituted catheterization data. Outcomes included achieving anatomic repair within 1 year of assessment in patients with LVOT obstruction or within 1 year of pulmonary artery banding and freedom from death, transplantation, or heart failure at last follow-up. Forty-one patients met the inclusion criteria. PAB/LVOT gradients of 85.2 ± 23.4 versus 64.0 ± 32.1 mm Hg (P = .0282) by echocardiography and 60.1 ± 19.4 versus 35.9 ± 18.9 mm Hg (P = .0030) by catheterization were associated with achieving anatomic repair and freedom from death, transplantation, and heart failure. Echocardiographic LV posterior wall thickening of 35.4 ± 19.8% versus 20.6

  7. Stimulated release of tissue plasminogen activator from artery wall sympathetic nerves: implications for stress-associated wall damage.

    Science.gov (United States)

    Hao, Zhifang; Jiang, Xi; Sharafeih, Roshanak; Shen, Shujing; Hand, Arthur R; Cone, Robert E; O'Rourke, James

    2005-06-01

    Recurrent stress is clinically associated with early onset hypertension and coronary artery disease. A mechanism linking emotion to pathogenic remodeling of the artery wall has not been identified. Stress stimulates acute regulated release of tissue plasminogen activator (t-PA) into the circulation, which is presently attributed to the vascular endothelium. Sympathetic neurons also synthesize t-PA and axonally transport it to the arterial smooth muscle. Unlike release by the endothelium, a stress-stimulated sympathetic discharge would potentially accelerate degradation of the wall matrix by plasmin. To assess whether sympathetic axons are the principal source of acute stress-induced arterial release of t-PA, we compared the output from small densely innervated and large sparsely innervated isolated artery segments before and after sympathetic stimulation, and after ablations. Following phenylephrine infusion densely-innervated microvessels in uveal eyecups were released over 60-fold greater amounts of active t-PA per milligram than the sparsely innervated aorta; and ten-fold more than carotid artery segments. Mesenteric artery release was 4.8-fold greater than release by the carotid artery. In vivo, uveal release of t-PA increased more than three-fold within one minute following superior cervical sympathetic ganglion electrical stimulation, and after phenylephrine, or nicotine infusions of the anterior chamber. Circulating levels of t-PA fell 70% following chemical sympathectomy. We propose that sympathetic nerves are the primary source of stress-induced release of t-PA into and from the densely innervated resistance arteries and arterioles, where dysregulated plasmin-induced proteolysis could damage the wall matrix.

  8. Stress state of thin – walled member of the structure with operation damages under nonuniform loading

    Directory of Open Access Journals (Sweden)

    В.В. Астанін

    2004-01-01

    Full Text Available  The publication is dedicated to determining of stress state in particular the stress concentration factors for thin – walled members of the structures subject to nonuniform tension. A structure member has obtained the operation damage generation by corrosion and other causes.

  9. [Effects of long-term exercise training on left ventricular function and remodeling in patients with anterior wall myocardial infarction].

    Science.gov (United States)

    Rivas-Estany, Eduardo; Sixto-Fernández, Sherien; Barrera-Sarduy, José; Hernández-García, Susana; González-Guerra, Roberto; Stusser-Beltranena, Rodolfo

    2013-01-01

    To assess the effects of long-term exercise training on the function and remodeling of the left ventricle after myocardial infarction. We studied 90 patients with a first acute anterior-wall myocardial infarction, all received conventional medical treatment. Symptom-limited maximal exercise stress tests, echocardiograms and effort-rest isotopic ventriculographies at 2, 6 and 12 months after myocardial infarction were performed; the follow-up time averaged 36.3±17 months. All patients joined a cardiac rehabilitation program with moderate or intense exercise training lasting at least a year. Of all patients, 41.1% suffered severe left ventricle dysfunction. Ergometric parameters that expressed functional capacity increased significantly (Pcardiovascular cause. Long-term exercise training showed no deleterious effects on left ventricle function or remodeling and beneficial functional and clinical effects were obtained in these rehabilitated postinfarction patients. Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  10. Comparison of actual and allowable stress values for out-of-plane shear on masonry walls

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, R.C.; Wilson, G.S.; Crouch, L.K.; Sneed, W.A. Jr.

    1999-07-01

    This paper presents research results from the testing of 16 masonry wall specimens in direct out-of-plane shear. The wall specimens were two courses high and 1.2 m (48 in.) long. The walls were nongrouted and were constructed with face-shell bedding only. The testing apparatus was configured such that failure mechanisms other than direct out-of-plane shear (i.e., those resulting from flexural and axial loads) were minimized. Shear stress values from the 16 wall tests are compared with allowable shear stress values obtained in ACI 530 / ASCE 5 / TMS 402. These results show that the code allowable shear stress values appear to be unconservative for this application of out-of-plane shear. It was found that the walls tested failed in out-of-shear at an average shear force of 69.8 kN (15,696 lb). This force produced an average shear stress of 0.349 MPa (50.65 psi) based on parabolic stress distribution and 0.885 Mpa (128.36 psi) for pure shear stress.

  11. Quantification of Stretching in the Ventricular Wall and Corpus Callosum and Corticospinal Tracts in Hydrocephalus before and after Ventriculoperitoneal Shunt Operation

    Directory of Open Access Journals (Sweden)

    Hans von Holst

    2013-01-01

    Full Text Available In this study, we establish a quantitative model to define the stretching of brain tissue, especially in ventricular walls, corpus callosum (CC and corticospinal (CS fiber tracts, and to investigate the correlation between stretching and regional cerebral blood flow (rCBF before and after ventriculoperitoneal shunt operations. A nonlinear image registration method was used to calculate the degree of displacement and stretching of axonal fiber tracts based on the medical images of six hydrocephalus patients. Also, the rCBF data from the literature was analyzed and correlated with the strain level quantified in the present study. The results showed substantial increased displacement and strain levels in the ventricular walls as well as in the CC and CS fiber tracts on admission. Following shunt operations the displacement as well as the strain levels reduced substantially. A linear correlation was found to exist between strain level and the rCBF. The reduction in postoperative strain levels correlated with the improvement of rCBF. All patients improved clinically except for one patient due to existing dementia. These new quantitative data provide us with new insight into the mechanical cascade of events due to tissue stretching, thereby provide us with more knowledge into understanding of the role of brain tissue and axonal stretching in some of the hydrocephalus clinical symptoms.

  12. Characteristics of the response of the iliac artery to wall shear stress in the anaesthetized pig.

    Science.gov (United States)

    Kelly, R F; Snow, H M

    2007-07-15

    The functional significance of shear stress-induced vasodilatation in large conduit arteries is unclear since changes in the diameter have little effect on the resistance to blood flow. However, changes in diameter have a relatively large effect on wall shear stress which suggests that the function of flow-mediated dilatation is to reduce wall shear stress. The mean and pulsatile components of shear stress vary widely throughout the arterial system and areas of low mean and high amplitude of wall shear stress are prone to the development of atheroma. In this study, using an in vivo model with the ability to control flow rate and amplitude of flow independently, we investigated the characteristics of the response of the iliac artery to variations in both the mean and amplitude of wall shear stress. The results of this study confirm that increases in mean wall shear stress are an important stimulus for the release of nitric oxide by the endothelium as indicated by changes in arterial diameter and show for the first time, in vivo, that increases in the amplitude of the pulsatile component of shear stress have a small but significant inhibitory effect on this response. A negative feedback mechanism was identified whereby increases in shear stress brought about by increases in blood flow are reduced by the release of nitric oxide from the endothelium causing dilatation of the artery, thus decreasing the stimulus to cell adhesion and, through a direct action of nitric oxide, inhibiting the process of cell adhesion. The results also provide an explanation for the uneven distribution of atheroma throughout the arterial system, which is related to the ratio of pulsatile to mean shear stress and consequent variability in the production of NO.

  13. Reciprocal Interactions between Cadmium-Induced Cell Wall Responses and Oxidative Stress in Plants

    Science.gov (United States)

    Loix, Christophe; Huybrechts, Michiel; Vangronsveld, Jaco; Gielen, Marijke; Keunen, Els; Cuypers, Ann

    2017-01-01

    Cadmium (Cd) pollution renders many soils across the world unsuited or unsafe for food- or feed-orientated agriculture. The main mechanism of Cd phytotoxicity is the induction of oxidative stress, amongst others through the depletion of glutathione. Oxidative stress can damage lipids, proteins, and nucleic acids, leading to growth inhibition or even cell death. The plant cell has a variety of tools to defend itself against Cd stress. First and foremost, cell walls might prevent Cd from entering and damaging the protoplast. Both the primary and secondary cell wall have an array of defensive mechanisms that can be adapted to cope with Cd. Pectin, which contains most of the negative charges within the primary cell wall, can sequester Cd very effectively. In the secondary cell wall, lignification can serve to immobilize Cd and create a tougher barrier for entry. Changes in cell wall composition are, however, dependent on nutrients and conversely might affect their uptake. Additionally, the role of ascorbate (AsA) as most important apoplastic antioxidant is of considerable interest, due to the fact that oxidative stress is a major mechanism underlying Cd toxicity, and that AsA biosynthesis shares several links with cell wall construction. In this review, modifications of the plant cell wall in response to Cd exposure are discussed. Focus lies on pectin in the primary cell wall, lignification in the secondary cell wall and the importance of AsA in the apoplast. Regarding lignification, we attempt to answer the question whether increased lignification is merely a consequence of Cd toxicity, or rather an elicited defense response. We propose a model for lignification as defense response, with a central role for hydrogen peroxide as substrate and signaling molecule. PMID:29163592

  14. Reciprocal Interactions between Cadmium-Induced Cell Wall Responses and Oxidative Stress in Plants

    Directory of Open Access Journals (Sweden)

    Christophe Loix

    2017-10-01

    Full Text Available Cadmium (Cd pollution renders many soils across the world unsuited or unsafe for food- or feed-orientated agriculture. The main mechanism of Cd phytotoxicity is the induction of oxidative stress, amongst others through the depletion of glutathione. Oxidative stress can damage lipids, proteins, and nucleic acids, leading to growth inhibition or even cell death. The plant cell has a variety of tools to defend itself against Cd stress. First and foremost, cell walls might prevent Cd from entering and damaging the protoplast. Both the primary and secondary cell wall have an array of defensive mechanisms that can be adapted to cope with Cd. Pectin, which contains most of the negative charges within the primary cell wall, can sequester Cd very effectively. In the secondary cell wall, lignification can serve to immobilize Cd and create a tougher barrier for entry. Changes in cell wall composition are, however, dependent on nutrients and conversely might affect their uptake. Additionally, the role of ascorbate (AsA as most important apoplastic antioxidant is of considerable interest, due to the fact that oxidative stress is a major mechanism underlying Cd toxicity, and that AsA biosynthesis shares several links with cell wall construction. In this review, modifications of the plant cell wall in response to Cd exposure are discussed. Focus lies on pectin in the primary cell wall, lignification in the secondary cell wall and the importance of AsA in the apoplast. Regarding lignification, we attempt to answer the question whether increased lignification is merely a consequence of Cd toxicity, or rather an elicited defense response. We propose a model for lignification as defense response, with a central role for hydrogen peroxide as substrate and signaling molecule.

  15. Analysis of domain wall dynamics based on skewness of magnetic Barkhausen noise for applied stress determination

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Song [College of Electrical Engineering and Control Science, Nanjing Tech University, Nanjing, Jiangsu 211816 (China); School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Tian, GuiYun, E-mail: tian280@hotmail.com [School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); School of Electrical and Electronic Engineering, Merz Court, University of Newcastle upon Tyne, Newcastle NE1 7RU (United Kingdom); Dobmann, Gerd; Wang, Ping [School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China)

    2017-01-01

    Skewness of Magnetic Barkhausen Noise (MBN) signal is used as a new feature for applied stress determination. After experimental studies, skewness presents its ability for measuring applied tensile stress compared with conventional feature, meanwhile, a non-linear behavior of this new feature and an independence of the excitation conditions under compressive stress are found and discussed. Effective damping during domain wall motion influencing the asymmetric shape of the MBN statistical distribution function is discussed under compressive and tensile stress variation. Domain wall (DW) energy and distance between pinning edges of the DW are considered altering the characteristic relaxation time, which is the reason for the non-linear phenomenon of skewness. - Highlights: • The skewness of magnetic Barkhausen noise profile is proposed as a new feature for applied stress determination. • The skewness is sensitive to applied stress and independent to excitation frequency. • Domain wall energy and pinning distance influence the relaxation time of domain wall, which leads to a non-linear behavior of skewness under compressive stress.

  16. Oxidative Stress State Is Associated with Left Ventricular Mechanics Changes, Measured by Speckle Tracking in Essential Hypertensive Patients

    Directory of Open Access Journals (Sweden)

    Luis Antonio Moreno-Ruíz

    2015-01-01

    Full Text Available The oxidative stress state is characterized by an increase in oxygen reactive species that overwhelms the antioxidant defense; we do not know if these pathological changes are correlated with alterations in left ventricular mechanics. The aim was correlating the oxidative stress state with the left ventricular global longitudinal strain (GLS and the left ventricular end diastolic pressure (LVEDP. Twenty-five patients with essential hypertension and 25 controls paired by age and gender were studied. All of the participants were subjected to echocardiography and biochemical determination of oxidative stress markers. The hypertensive patients, compared with control subjects, had significantly (p<0.05 higher levels of oxidized proteins (5.03±1.05 versus 4.06±0.63 nmol/mg, lower levels of extracellular superoxide dismutase (EC-SOD activity (0.045±0.02 versus 0.082±0.02 U/mg, higher LVEDP (16.2±4.5 versus 11.3±1.6 mm Hg, and lower GLS (−12% versus −16%. Both groups had preserved ejection fraction and the results showed a positive correlation of oxidized proteins with GLS (r=0.386, p=0.006 and LVEDP (r=0.389, p=0.005; we also found a negative correlation of EC-SOD activity with GLS (r=-0.404, p=0.004 and LVEDP (r=-0.347, p=0.014.

  17. LATE POTENTIALS IN A PORCINE MODEL OF ANTERIOR WALL MYOCARDIAL-INFARCTION AND THEIR RELATION TO INDUCIBLE VENTRICULAR-TACHYCARDIA

    NARCIS (Netherlands)

    TOBE, TJM; DELANGEN, CDJ; MOOK, PH; TIO, RA; BEL, KJ; DEGRAEFF, PA; VANGILST, WH; WESSELING, H

    1992-01-01

    In this study, normal values for signal averaged electrocardiographic parameters were assessed in healthy pigs (n = 100) and the development of late potentials after myocardial infarction (n = 41) in relation to inducible ventricular tachycardia was investigated. Normal values are: filtered QRS

  18. Effects of wall shear stress on unsteady MHD conjugate flow in a porous medium with ramped wall temperature.

    Science.gov (United States)

    Khan, Arshad; Khan, Ilyas; Ali, Farhad; Ulhaq, Sami; Shafie, Sharidan

    2014-01-01

    This study investigates the effects of an arbitrary wall shear stress on unsteady magnetohydrodynamic (MHD) flow of a Newtonian fluid with conjugate effects of heat and mass transfer. The fluid is considered in a porous medium over a vertical plate with ramped temperature. The influence of thermal radiation in the energy equations is also considered. The coupled partial differential equations governing the flow are solved by using the Laplace transform technique. Exact solutions for velocity and temperature in case of both ramped and constant wall temperature as well as for concentration are obtained. It is found that velocity solutions are more general and can produce a huge number of exact solutions correlative to various fluid motions. Graphical results are provided for various embedded flow parameters and discussed in details.

  19. T-stress solutions for through-wall circumferential cracks in straight pipes under bending

    OpenAIRE

    GINTALAS, M; Ainsworth, Robert; Scenini, Fabio

    2017-01-01

    This paper reports the results of an extensive series of finite element calculations to provide normalised T-stress solutions for through-wall cracked pipes under bending for a range of crack sizes and pipe radius to wall thickness ratios. Comparisons with the limited solutions in the literature are used to give confidence in the numerical solutions obtained, which are shown to be sensitive to mesh refinement. The results are provided in a form that is suitable for use in practical constraint...

  20. Alteration of mean wall shear stress near an oscillating stagnation point.

    Science.gov (United States)

    Hazel, A L; Pedley, T J

    1998-04-01

    The site opposite an end-to-side anastomosis, resulting from femoral bypass surgery, and the carotid sinus are two regions well known to be prone to fibrous intimal hyperplasia or atherogenesis, respectively. The blood flow at these two sites features a stagnation point, which oscillates in strength and position. Mathematical models are used to determine some of the features of such a flow; in particular, the mean wall shear stress is calculated. The positional oscillations cause a significant change in the distribution and magnitude of the mean wall shear stress from that of the well-studied case of a stagnation point that oscillates only in strength. It is therefore proposed that the recorded effect of time dependence in the flow upon atherogenesis could still be a result of the distribution of the mean and not the time-varying components of the wall shear stress.

  1. Debonding Stress Concentrations in a Pressurized Lobed Sandwich-Walled Generic Cryogenic Tank

    Science.gov (United States)

    Ko, William L.

    2004-01-01

    A finite-element stress analysis has been conducted on a lobed composite sandwich tank subjected to internal pressure and cryogenic cooling. The lobed geometry consists of two obtuse circular walls joined together with a common flat wall. Under internal pressure and cryogenic cooling, this type of lobed tank wall will experience open-mode (a process in which the honeycomb is stretched in the depth direction) and shear stress concentrations at the junctures where curved wall changes into flat wall (known as a curve-flat juncture). Open-mode and shear stress concentrations occur in the honeycomb core at the curve-flat junctures and could cause debonding failure. The levels of contributions from internal pressure and temperature loading to the open-mode and shear debonding failure are compared. The lobed fuel tank with honeycomb sandwich walls has been found to be a structurally unsound geometry because of very low debonding failure strengths. The debonding failure problem could be eliminated if the honeycomb core at the curve-flat juncture is replaced with a solid core.

  2. Convection of wall shear stress events in a turbulent boundary layer

    Science.gov (United States)

    Pabon, Rommel; Mills, David; Ukeiley, Lawrence; Sheplak, Mark

    2017-11-01

    The fluctuating wall shear stress is measured in a zero pressure gradient turbulent boundary layer of Reτ 1700 simultaneously with velocity measurements using either hot-wire anemometry or particle image velocimetry. These experiments elucidate the patterns of large scale structures in a single point measurement of the wall shear stress, as well as their convection velocity at the wall. The wall shear stress sensor is a CS-A05 one-dimensional capacitice floating element from Interdisciplinary Consulting Corp. It has a nominal bandwidth from DC to 5 kHz and a floating element size of 1 mm in the principal sensing direction (streamwise) and 0.2 mm in the cross direction (spanwise), allowing the large scales to be well resolved in the current experimental conditions. In addition, a two sensor array of CS-A05 aligned in the spanwise direction with streamwise separations O (δ) is utilized to capture the convection velocity of specific scales of the shear stress through a bandpass filter and peaks in the correlation. Thus, an average wall normal position for the corresponding convecting event can be inferred at least as high as the equivalent local streamwise velocity. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1315138.

  3. Prevention of the Rerupture of Collateral Artery Aneurysms on the Ventricular Wall by Early Surgical Revascularization in Moyamoya Disease: Report of Two Cases and Review of the Literature.

    Science.gov (United States)

    Kanamori, Fumiaki; Takasu, Syuntaro; Ota, Shinji; Seki, Yukio

    2018-01-01

    Collateral artery aneurysms are a source of intracranial hemorrhage in moyamoya disease. Several reports have shown that surgical revascularization leads to the obliteration of collateral artery aneurysms. However, its effect on the prevention of rebleeding has not been established, and the optimal timing of the operation remains unclear. The purpose of the present study is to evaluate the effects of surgical revascularization and to investigate the optimal operation timing in patients with moyamoya disease who have ruptured collateral artery aneurysms on the ventricular wall. Two patients with moyamoya disease who presented with intraventricular hemorrhage caused by rupture of collateral artery aneurysms on the wall of the lateral ventricle are presented here. In both cases, the aneurysms reruptured approximately 1 month after the initial hemorrhage. Both patients successfully underwent superficial temporal artery-middle cerebral artery anastomosis combined with indirect bypass in the subacute stage. The aneurysms decreased with the development of collateral circulation through the direct bypasses, and rebleeding did not occur after the surgery. Because ruptured collateral artery aneurysms on the wall of the lateral ventricle in moyamoya disease are prone to rerupture within 1 month, surgical revascularization may be recommended as soon as the patients are stable and able to withstand the operation. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. An Asymptomatic Case of Wolff-Parkinson-White Syndrome with Right-sided Free-wall Accessory Pathway and Left Ventricular Dysfunction

    Directory of Open Access Journals (Sweden)

    Takanao Mine, MD

    2011-01-01

    Full Text Available A 16-year-old girl with a known history of asymptomatic Wolff-Parkinson-White syndrome exhibited signs of left ventricular (LV septal akinesia and LV dysfunction during routine follow-up. A 12-lead surface ECG showed pre-excitation, a predominantly negative delta wave in V1 and left axis deviation, which was consistent with the presence of a right free-wall accessory pathway. Radiofrequency ablation of the anterolateral right atrium around the local shortest atrium-to-ventricle interval created the accessory pathway block. An echocardiogram taken one month after the procedure revealed that LV septal wall motion had normalized and that LV ejection fraction had improved from 50% before the ablation to 64% after the ablation. Most previous reports of asymptomatic patients of WPW with LV septal dyskinesia and dysfunction have described right septal or posteroseptal accessory pathways. This patient reported here represents a rare case with right free-wall accessory pathway and LV dysfunction without tachycardia.

  5. Intraprocedural left ventricular free wall rupture diagnosed by left ventriculogram in a patient with infero-posterior myocardial infarction and severe aortic stenosis.

    Science.gov (United States)

    Konishi, Takao; Funayama, Naohiro; Yamamoto, Tadashi; Nishihara, Hiroshi; Hotta, Daisuke; Kikuchi, Kenjiro; Yokoyama, Hideo; Ohori, Katsumi

    2016-06-06

    Left ventricular wall rupture remains a major lethal complication of acute myocardial infarction and hypertension is a well-known predisposing factor of cardiac rupture after myocardial infarction. An 87-year-old man was admitted to our hospital, diagnosed as acute myocardial infarction (AMI). The echocardiogram showed 0.67-cm(2) aortic valve, consistent with severe aortic stenosis (AS). A coronary angiography showed a chronic occlusion of the proximal left circumflex artery and a 99 % stenosis and thrombus in the mid right coronary artery. During percutaneous angioplasty of the latter, transient hypotension and bradycardia developed at the time of balloon inflation, and low doses of noradrenaline and etilefrine were intravenously administered as needed. The patient suddenly lost consciousness and developed electro-mechanical dissociation. Cardio-pulmonary resuscitation followed by insertion of an intra-aortic balloon pump (IABP) and percutaneous cardiopulmonary support were initiated. The echocardiogram revealed moderate pericardial effusion, though the site of free wall rupture was not distinctly visible. A left ventriculogram clearly showed an infero-posterior apical wall rupture. Surgical treatment was withheld because of the interim development of brain death. In this patient, who presented with severe AS, the administration of catecholamine to stabilize the blood pressure probably increased the intraventricular pressures considerably despite apparently normal measurements of the central aortic pressure. IABP, temporary pacemaker, or both are recommended instead of intravenous catecholamines for patients with AMI complicated with significant AS to stabilize hemodynamic function during angioplasty.

  6. Correlation between vortices and wall shear stress in a curved artery model under pulsatile flow conditions

    Science.gov (United States)

    Cox, Christopher; Plesniak, Michael W.

    2017-11-01

    One of the most physiologically relevant factors within the cardiovascular system is the wall shear stress. The wall shear stress affects endothelial cells via mechanotransduction and atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. In this work, our goal is to assess the correlation between multiple vortex pairs and wall shear stress. To accomplish this, we use an in-house high-order flux reconstruction Navier-Stokes solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180° curved artery model. We use a physiologically relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter motivated by the fact that flow upstream to a curved artery may not be fully developed. Under these two inflow conditions, we characterize the evolution of various vortex pairs and their subsequent effect on several wall shear stress metrics. Supported by GW Center for Biomimetics and Bioinspired Engineering.

  7. Effects of the three-dimensional residual stresses on the mechanical properties of arterial walls.

    Science.gov (United States)

    Zheng, Xianbing; Ren, Jiusheng

    2016-03-21

    Effects of the three-dimensional residual stresses on the mechanical properties of arterial walls are analyzed in this paper, based on the model which considered the bending and stretching both in the circumferential and axial directions of the three distinct arterial layers. Moreover, different constitutive models are proposed to quantify the nonlinear mechanics of the three distinct layers and the important constituents, i.e. elastin, collagen fibers and smooth muscle cells (SMCs), are all taken into account. The stress distributions and pressure-radius curves of the arterial wall are given in details. Results demonstrate that the maximum values of the circumferential stress and the corresponding stress gradient in the media under the mean arterial pressure are reduced significantly as a consequence of the SMCs. The bending in the axial direction of the media and the opening angle of the intima have an obvious impact on the mechanical behaviors of arterial walls. This study may not only develop the understanding of effects of the three-dimensional residual stresses on the arterial wall response, but also can increase the accuracy of the analyses for patient-specific studies used for the treatments of arterial diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Influence of diaphragm wall installation in overconsolidated sandy clays on in situ stress disturbance and resulting wall deformations

    Directory of Open Access Journals (Sweden)

    Truty Andrzej Adam

    2016-09-01

    Full Text Available Numerical modeling of deep excavations becomes a standard practice in modern geotechnical engineering. A detailed numerical model for a given case is able to reproduce major effects of soil-structure interaction by taking into account any kind of drainage conditions, strong stiffness variation due to effective stress and strain changes, creep and cracking, when reinforced concrete is used as a structural material, but also interface effects between subsoil and structure. Calibrating soil constitutive models is one of the most difficult tasks and due to several sources of uncertainty there is no one unique set of the data that should be used in numerical predictions. Lack or incompleteness of experimental data, significant mismatch between laboratory and field tests is an another source of difficulty. Contrary to several simplified methods, that are usually limited to two dimensions, numerical models allow a full 3D analysis in which many simplifications can be eliminated. This paper is devoted to the problem of in situ stress disturbance caused by diaphragm wall installation in overconsolidated quaternary sandy clays and its influence on final wall deformations.

  9. Interaction between left ventricular wall motion and intraventricular flow propagation in acute and chronic ischemia.(Author Abstract)

    National Research Council Canada - National Science Library

    Edvardsen, Thor; Endresen, Knut; Ihlen, Halfdan; Rodevand, Olaf

    2005-01-01

    .... The combination of tissue Doppler imaging and high framerate acquisition of two-dimensional color flow makes it possible to study the interaction between LV wall motion and intraventricular flow propagation...

  10. Posterior wall involvement attenuates predictive value of ST-segment elevation in lead V4R for right ventricular involvement in inferior acute myocardial infarction.

    Science.gov (United States)

    Kosuge, Masami; Ishikawa, Toshiyuki; Morita, Satoshi; Ebina, Toshiaki; Hibi, Kiyoshi; Maejima, Nobuhiko; Umemura, Satoshi; Kimura, Kazuo

    2009-12-01

    ST-segment elevation of ≥1.0 mm in the right precordial chest lead V4R (ST↑V4R) has been shown to be a reliable marker of right ventricular involvement (RVI) in inferior acute myocardial infarction (IMI). However, the impact of left ventricular posterior wall involvement (PWI) on the relation between ST↑V4R and RVI is unknown. We studied 267 patients with recanalized IMI due to the right coronary artery (RCA) occlusion within 6h after symptom onset. A 12-lead electrocardiogram, lead V4R, and leads V7-9 were recorded on admission. RVI was defined as occlusion proximal to the first major right ventricular branch of the RCA. The perfusion territory of the RCA was assessed by angiographic distribution score, and PWI was defined as a score of ≥0.7. Patients were stratified according to the presence or absence of PWI and RVI. RVI was associated with higher peak creatine kinase and a higher rate of impaired myocardial reperfusion, defined as a myocardial blush grade of 0 or 1 after recanalization, in the presence or absence of PWI, especially the former. RVI was associated with a higher rate of ST↑V4R in the absence, but not in the presence, of PWI. ST↑V4R identified RVI with sensitivities of 34% and 96% (pPWI, respectively. In patients with recanalized IMI, RVI is associated with larger infarction and impaired myocardial reperfusion in the presence or absence of PWI, especially the former. However, the presence of PWI attenuates the predictive value of ST↑V4R for RVI.

  11. The CWI Pathway: Regulation of the Transcriptional Adaptive Response to Cell Wall Stress in Yeast

    Directory of Open Access Journals (Sweden)

    Ana Belén Sanz

    2017-12-01

    Full Text Available Fungi are surrounded by an essential structure, the cell wall, which not only confers cell shape but also protects cells from environmental stress. As a consequence, yeast cells growing under cell wall damage conditions elicit rescue mechanisms to provide maintenance of cellular integrity and fungal survival. Through transcriptional reprogramming, yeast modulate the expression of genes important for cell wall biogenesis and remodeling, metabolism and energy generation, morphogenesis, signal transduction and stress. The yeast cell wall integrity (CWI pathway, which is very well conserved in other fungi, is the key pathway for the regulation of this adaptive response. In this review, we summarize the current knowledge of the yeast transcriptional program elicited to counterbalance cell wall stress situations, the role of the CWI pathway in the regulation of this program and the importance of the transcriptional input received by other pathways. Modulation of this adaptive response through the CWI pathway by positive and negative transcriptional feedbacks is also discussed. Since all these regulatory mechanisms are well conserved in pathogenic fungi, improving our knowledge about them will have an impact in the developing of new antifungal therapies.

  12. Direct measurement of cell wall stress-stiffening and turgor pressure in live bacterial cells

    CERN Document Server

    Deng, Yi; Shaevitz, Joshua W

    2011-01-01

    The mechanical properties of gram-negative bacteria are governed by a rigid peptidoglycan (PG) cell wall and the turgor pressure generated by the large concentration of solutes in the cytoplasm. The elasticity of the PG has been measured in bulk and in isolated sacculi and shown to be compliant compared to the overall stiffness of the cell itself. However, the stiffness of the cell wall in live cells has not been measured. In particular, the effects that pressure-induced stress might have on the stiffness of the mesh-like PG network have not been addressed even though polymeric materials often exhibit large amounts of stress-stiffening. We study bulging Escherichia coli cells using atomic force microscopy to separate the contributions of the cell wall and turgor pressure to the overall cell stiffness. We find strong evidence of power-law stress-stiffening in the E. coli cell wall, with an exponent of $1.07 \\pm 0.25$, such that the wall is significantly stiffer in live cells ($E\\sim32\\pm10$ MPa) than in unpres...

  13. Feature extraction and wall motion classification of 2D stress echocardiography with support vector machines

    Science.gov (United States)

    Chykeyuk, Kiryl; Clifton, David A.; Noble, J. Alison

    2011-03-01

    Stress echocardiography is a common clinical procedure for diagnosing heart disease. Clinically, diagnosis of the heart wall motion depends mostly on visual assessment, which is highly subjective and operator-dependent. Introduction of automated methods for heart function assessment have the potential to minimise the variance in operator assessment. Automated wall motion analysis consists of two main steps: (i) segmentation of heart wall borders, and (ii) classification of heart function as either "normal" or "abnormal" based on the segmentation. This paper considers automated classification of rest and stress echocardiography. Most previous approaches to the classification of heart function have considered rest or stress data separately, and have only considered using features extracted from the two main frames (corresponding to the end-of-diastole and end-of-systole). One previous attempt [1] has been made to combine information from rest and stress sequences utilising a Hidden Markov Model (HMM), which has proven to be the best performing approach to date. Here, we propose a novel alternative feature selection approach using combined information from rest and stress sequences for motion classification of stress echocardiography, utilising a Support Vector Machines (SVM) classifier. We describe how the proposed SVM-based method overcomes difficulties that occur with HMM classification. Overall accuracy with the new method for global wall motion classification using datasets from 173 patients is 92.47%, and the accuracy of local wall motion classification is 87.20%, showing that the proposed method outperforms the current state-of-the-art HMM-based approach (for which global and local classification accuracy is 82.15% and 78.33%, respectively).

  14. Systolic left ventricular function according to left ventricular concentricity and dilatation in hypertensive patients

    DEFF Research Database (Denmark)

    Bang, Casper; Gerdts, Eva; Aurigemma, Gerard P

    2013-01-01

    Left ventricular hypertrophy [LVH, high left ventricular mass (LVM)] is traditionally classified as concentric or eccentric based on left ventricular relative wall thickness. We evaluated left ventricular systolic function in a new four-group LVH classification based on left ventricular dilatatio...

  15. Stress Distribution in Continuous Thin-Walled Multi-Cell Box Girder ...

    African Journals Online (AJOL)

    The modern trend in the analysis is to program the more straightforward methods for ease of computer application. Therefore, the analytical tool for this study is a MATLAB program developed by the authors for the finite strip analysis of continuous thin-walled box girder bridges. Numerical study on stress distribution was ...

  16. Orientation on quantitative IR-thermografy in wall-shear stress measurements

    NARCIS (Netherlands)

    Mayer, R.

    1998-01-01

    Wall-shear stresses are highly important in the aerodynamic design of aircraft, because they determine the drag and thus the fuel consumption of an airplane. Due to this importance many different measurement techniques have been developed. Most of these techniques are intrusive, which means that the

  17. Flow rate dependency of critical wall shear stress in a radial-flow cell

    DEFF Research Database (Denmark)

    Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.

    2009-01-01

    In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersi...

  18. Volumetric Arterial Wall Shear Stress Calculation Based on Cine Phase Contrast MRI

    NARCIS (Netherlands)

    Potters, Wouter V.; van Ooij, Pim; Marquering, Henk; VanBavel, Ed; Nederveen, Aart J.

    2015-01-01

    PurposeTo assess the accuracy and precision of a volumetric wall shear stress (WSS) calculation method applied to cine phase contrast magnetic resonance imaging (PC-MRI) data. Materials and MethodsVolumetric WSS vectors were calculated in software phantoms. WSS algorithm parameters were optimized

  19. Frequency of Inverted Electrocardiographic T Waves (Cerebral T Waves) in Patients With Acute Strokes and Their Relation to Left Ventricular Wall Motion Abnormalities.

    Science.gov (United States)

    Stone, Jeremy; Mor-Avi, Victor; Ardelt, Agnieszka; Lang, Roberto M

    2018-01-01

    Transient, symmetric, and deep inverted electrocardiogram (ECG) T waves in the setting of stroke, commonly referred to as cerebral T waves, are rare, and the underlying mechanism is unclear. Our study aimed to test the hypothesis that cerebral T waves are associated with transient cardiac dysfunction. This retrospective study included 800 patients admitted with the primary diagnosis of hemorrhagic or ischemic stroke. ECGs were examined for cerebral T waves, defined as T-wave inversion of ≥5 mm depth in ≥4 contiguous precordial leads. Echocardiograms of those meeting these criteria were examined for the presence of left ventricular (LV) wall motion abnormalities. Follow-up evaluation included both ECG and echocardiogram. Of the 800 patients, 17 had cerebral T waves on ECG (2.1%). All 17 patients had ischemic strokes, of which 11 were in the middle cerebral artery distribution (65%), and 2 were cerebellar (12%), whereas the remaining 4 involved other locations. Follow-up ECG showed resolution of the T-wave changes in all 17 patients. Of these patients, 14 (82%) had normal wall motion, and 3 had transient wall motion abnormalities (18%). Two of these patients had Takotsubo-like cardiomyopathy with apical ballooning, and the third had globally reduced LV function. Coronary angiography showed no significant disease to explain the LV dysfunction. In summary, in our cohort of patients with acute stroke, cerebral T waves were rare and occurred only in ischemic stroke. Eighteen percent of patients with cerebral T waves had significant transient wall motion abnormalities. Patients with stroke with cerebral T waves, especially in those with ischemic strokes, should be assessed for cardiac dysfunction. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Exercise-mediated changes in conduit artery wall thickness in humans: role of shear stress.

    Science.gov (United States)

    Thijssen, Dick H J; Dawson, Ellen A; van den Munckhof, Inge C L; Tinken, Toni M; den Drijver, Evert; Hopkins, Nicola; Cable, N Timothy; Green, Daniel J

    2011-07-01

    Episodic increases in shear stress have been proposed as a mechanism that induces training-induced adaptation in arterial wall remodeling in humans. To address this hypothesis in humans, we examined bilateral brachial artery wall thickness using high-resolution ultrasound in healthy men across an 8-wk period of bilateral handgrip training. Unilaterally, shear rate was attenuated by cuff inflation around the forearm to 60 mmHg. Grip strength, forearm volume, and girth improved similarly between the limbs. Acute bouts of handgrip exercise increased shear rate (P < 0.005) in the noncuffed limb, whereas cuff inflation successfully decreased exercise-induced increases in shear. Brachial blood pressure responses similarly increased during exercise in both the cuffed and noncuffed limbs. Handgrip training had no effect on baseline brachial artery diameter, blood flow, or shear rate but significantly decreased brachial artery wall thickness after 6 and 8 wk (ANOVA, P < 0.001) and wall-to-lumen ratio after week 8 (ANOVA, P = 0.005). The magnitude of decrease in brachial artery wall thickness and wall-to-lumen ratio after exercise training was similar in the noncuffed and cuffed arms. These results suggest that exercise-induced changes in shear rate are not obligatory for arterial wall remodeling during a period of 8 wk of exercise training in healthy humans.

  1. Cell wall modification in grapevine cells in response to UV stress investigated by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lesniewska, E.; Adrian, M.; Klinguer, A.; Pugin, A

    2004-08-15

    Despite cell wall reinforcement being a well-known defence mechanism of plants, it remains poorly characterized from a physical point of view. The objective of this work was to further describe this mechanism. Vitis vinifera cv Gamay cells were treated with UV-light (254 nm), a well-known elicitor of defence mechanisms in grapevines, and physical cell wall modifications were observed using the atomic force microscopy (AFM) under native conditions. The grapevine cell suspensions were continuously observed in their culture medium from 30 min to 24 h after elicitation. In the beginning, cellulose fibrils covered by a matrix surrounded the control and treated cells. After 3 h, the elicited cells displayed sprouted expansions around the cell wall that correspond to pectin chains. These expansions were not observed on untreated grapevine cells. The AFM tip was used to determine the average surface elastic modulus of cell wall that account for cell wall mechanical properties. The elasticity is diminished in UV-treated cells. In a comparative study, grapevine cells showed the same decrease in cell wall elasticity when treated with a fungal biotic elicitor of defence response. These results demonstrate cell wall strengthening by UV stress.

  2. Estimation of aneurysm wall stresses created by treatment with a shape memory polymer foam device.

    Science.gov (United States)

    Hwang, Wonjun; Volk, Brent L; Akberali, Farida; Singhal, Pooja; Criscione, John C; Maitland, Duncan J

    2012-05-01

    In this study, compliant latex thin-walled aneurysm models are fabricated to investigate the effects of expansion of shape memory polymer foam. A simplified cylindrical model is selected for the in-vitro aneurysm, which is a simplification of a real, saccular aneurysm. The studies are performed by crimping shape memory polymer foams, originally 6 and 8 mm in diameter, and monitoring the resulting deformation when deployed into 4-mm-diameter thin-walled latex tubes. The deformations of the latex tubes are used as inputs to physical, analytical, and computational models to estimate the circumferential stresses. Using the results of the stress analysis in the latex aneurysm model, a computational model of the human aneurysm is developed by changing the geometry and material properties. The model is then used to predict the stresses that would develop in a human aneurysm. The experimental, simulation, and analytical results suggest that shape memory polymer foams have potential of being a safe treatment for intracranial saccular aneurysms. In particular, this work suggests oversized shape memory foams may be used to better fill the entire aneurysm cavity while generating stresses below the aneurysm wall breaking stresses.

  3. Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics

    Science.gov (United States)

    2011-01-01

    Background Staphylococcus aureus activates a protective cell wall stress stimulon (CWSS) in response to the inhibition of cell wall synthesis or cell envelope damage caused by several structurally and functionally different antibiotics. CWSS induction is coordinated by the VraSR two-component system, which senses an unknown signal triggered by diverse cell wall active agents. Results We have constructed a highly sensitive luciferase reporter gene system, using the promoter of sas016 (S. aureus N315), which detects very subtle differences in expression as well as measuring > 4 log-fold changes in CWSS activity, to compare the concentration dependence of CWSS induction kinetics of antibiotics with different cell envelope targets. We compared the effects of subinhibitory up to suprainhibitory concentrations of fosfomycin, D-cycloserine, tunicamycin, bacitracin, flavomycin, vancomycin, teicoplanin, oxacillin, lysostaphin and daptomycin. Induction kinetics were both strongly antibiotic- and concentration-dependent. Most antibiotics triggered an immediate response with induction beginning within 10 min, except for tunicamycin, D-cycloserine and fosfomycin which showed lags of up to one generation before induction commenced. Induction characteristics, such as the rate of CWSS induction once initiated and maximal induction reached, were strongly antibiotic dependent. We observed a clear correlation between the inhibitory effects of specific antibiotic concentrations on growth and corresponding increases in CWSS induction kinetics. Inactivation of VraR increased susceptibility to the antibiotics tested from 2- to 16-fold, with the exceptions of oxacillin and D-cycloserine, where no differences were detected in the methicillin susceptible S. aureus strain background analysed. There was no apparent correlation between the induction capacity of the various antibiotics and the relative importance of the CWSS for the corresponding resistance phenotypes. Conclusion CWSS induction

  4. Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics

    Directory of Open Access Journals (Sweden)

    Berger-Bächi Brigitte

    2011-01-01

    Full Text Available Abstract Background Staphylococcus aureus activates a protective cell wall stress stimulon (CWSS in response to the inhibition of cell wall synthesis or cell envelope damage caused by several structurally and functionally different antibiotics. CWSS induction is coordinated by the VraSR two-component system, which senses an unknown signal triggered by diverse cell wall active agents. Results We have constructed a highly sensitive luciferase reporter gene system, using the promoter of sas016 (S. aureus N315, which detects very subtle differences in expression as well as measuring > 4 log-fold changes in CWSS activity, to compare the concentration dependence of CWSS induction kinetics of antibiotics with different cell envelope targets. We compared the effects of subinhibitory up to suprainhibitory concentrations of fosfomycin, D-cycloserine, tunicamycin, bacitracin, flavomycin, vancomycin, teicoplanin, oxacillin, lysostaphin and daptomycin. Induction kinetics were both strongly antibiotic- and concentration-dependent. Most antibiotics triggered an immediate response with induction beginning within 10 min, except for tunicamycin, D-cycloserine and fosfomycin which showed lags of up to one generation before induction commenced. Induction characteristics, such as the rate of CWSS induction once initiated and maximal induction reached, were strongly antibiotic dependent. We observed a clear correlation between the inhibitory effects of specific antibiotic concentrations on growth and corresponding increases in CWSS induction kinetics. Inactivation of VraR increased susceptibility to the antibiotics tested from 2- to 16-fold, with the exceptions of oxacillin and D-cycloserine, where no differences were detected in the methicillin susceptible S. aureus strain background analysed. There was no apparent correlation between the induction capacity of the various antibiotics and the relative importance of the CWSS for the corresponding resistance phenotypes

  5. The Role of Plant Cell Wall Proteins in Response to Salt Stress

    Directory of Open Access Journals (Sweden)

    Lyuben Zagorchev

    2014-01-01

    Full Text Available Contemporary agriculture is facing new challenges with the increasing population and demand for food on Earth and the decrease in crop productivity due to abiotic stresses such as water deficit, high salinity, and extreme fluctuations of temperatures. The knowledge of plant stress responses, though widely extended in recent years, is still unable to provide efficient strategies for improvement of agriculture. The focus of study has been shifted to the plant cell wall as a dynamic and crucial component of the plant cell that could immediately respond to changes in the environment. The investigation of plant cell wall proteins, especially in commercially important monocot crops revealed the high involvement of this compartment in plants stress responses, but there is still much more to be comprehended. The aim of this review is to summarize the available data on this issue and to point out the future areas of interest that should be studied in detail.

  6. Analysis of Stress and Strain Distribution in the Artery Wall Consisted of Layers with Different Elastic Modulus and Opening Angle

    Science.gov (United States)

    Matsumoto, Takeo; Sato, Masaaki

    Bovine thoracic aorta is stiffer in the inner wall than in the outer, and its opening angle is larger in the inner layer than in the outer. A model for mechanical analysis of such a heterogeneous artery wall was developed. The wall was assumed to be made of thin, incompressible, homogeneous, and isotropic layers having different elastic properties and opening angle. Stress and strain distributions in the wall were calculated using the opening angle and stress-strain relationship measured in thin sliced layers of bovine thoracic aortas. Stress distribution was uniform under a physiological condition if elastic properties and the opening angle were set uniform. Stress distribution was not uniform under any condition when the material heterogeneity was introduced. Such non-uniformity was reduced if heterogeneity in the opening angle was considered. The opening angle may be higher in the inner wall to compensate stress concentration caused by the material heterogeneity.

  7. Targeted electroporation of defined lateral ventricular walls: a novel and rapid method to study fate specification during postnatal forebrain neurogenesis

    Science.gov (United States)

    2011-01-01

    Background Postnatal olfactory bulb (OB) neurogenesis involves the generation of granule and periglomerular cells by neural stem cells (NSCs) located in the walls of the lateral ventricle (LV). Recent studies show that NSCs located in different regions of the LV give rise to different types of OB neurons. However, the molecular mechanisms governing neuronal specification remain largely unknown and new methods to approach these questions are needed. Results In this study, we refine electroporation of the postnatal forebrain as a technique to perform precise and accurate delivery of transgenes to NSCs located in distinct walls of the LV in the mouse. Using this method, we confirm and expand previous studies showing that NSCs in distinct walls of the LV produce neurons that invade different layers of the OB. Fate mapping of the progeny of radial glial cells located in these distinct LV walls reveals their specification into defined subtypes of granule and periglomerular neurons. Conclusions Our results provide a baseline with which future studies aiming at investigating the role of factors in postnatal forebrain neuronal specification can be compared. Targeted electroporation of defined LV NSC populations will prove valuable to study the genetic factors involved in forebrain neuronal specification. PMID:21466691

  8. The association between right ventricular free wall strain and exercise capacity for health check-up subjects.

    Science.gov (United States)

    Chang, Wei-Ting; Liu, Yen-Wen; Liu, Ping-Yen; Hsu, Chih-Hsin; Tsai, Wei-Chuan

    2017-01-01

    Right ventricular (RV) function has been found to be a major factor of exercise capacity in patients with heart failure. However, the role of RV function in exercise capacity in healthy subjects has not been well studied. This study aims to validate the role of RV strain derived from speckle tracking echocardiography for exercise capacity for health check-up subjects. This study prospectively recruited subjects from a routine health examination. All of them were symptom free. RV function represented by RV strain was derived from speckle tracking echocardiography in addition to traditional echocardiography parameters. Functional capacity was determined by a symptom limited treadmill exercise test with the Bruce protocol. Among 164 recruited subjects (age 52.2 ±9.2 years, 66.4% male), 32 subjects represented impaired functional capacity (METexercise capacity for health check-up subjects. RV function is an important factor for functional capacity.

  9. Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions

    Directory of Open Access Journals (Sweden)

    Sandip A. Ghuge

    2015-07-01

    Full Text Available Polyamines (PAs are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs, including copper amine oxidases (CuAOs and flavin adenine dinucleotide (FAD-dependent polyamine oxidases (PAOs. The biologically-active hydrogen peroxide (H2O2 is a shared compound in all of the AO-catalyzed reactions, and it has been reported to play important roles in PA-mediated developmental and stress-induced processes. In particular, the AO-driven H2O2 biosynthesis in the cell wall is well known to be involved in plant wound healing and pathogen attack responses by both triggering peroxidase-mediated wall-stiffening events and signaling modulation of defense gene expression. Extensive investigation by a variety of methodological approaches revealed high levels of expression of cell wall-localized AOs in root xylem tissues and vascular parenchyma of different plant species. Here, the recent progresses in understanding the role of cell wall-localized AOs as mediators of root xylem differentiation during development and/or under stress conditions are reviewed. A number of experimental pieces of evidence supports the involvement of apoplastic H2O2 derived from PA oxidation in xylem tissue maturation under stress-simulated conditions.

  10. Hemodynamic stress echocardiography in patients supported with a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Andersen, Mads; Gustafsson, Finn; Madsen, Per Lav

    2010-01-01

    Functional assessment of continuous-flow left ventricular assist devices (LVADs) is usually performed with the patient at rest. This study compared echocardiographic indices of contraction and filling pressure with invasive measures in 12 ambulatory LVAD patients undergoing symptom-limited bicycl...

  11. Validation of a novel modified wall motion score for estimation of left ventricular ejection fraction in ischemic and non-ischemic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Scholl, David, E-mail: David.Scholl@utoronto.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Kim, Han W., E-mail: hanwkim@gmail.com [Duke Cardiovascular Magnetic Resonance Center, Division of Cardiology, Duke University, NC (United States); Shah, Dipan, E-mail: djshah@tmhs.org [The Methodist DeBakey Heart Center, Houston, TX (United States); Fine, Nowell M., E-mail: nowellfine@gmail.com [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Tandon, Shruti, E-mail: standon4@uwo.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Thompson, Terry, E-mail: thompson@lawsonimaging.ca [Lawson Health Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); Drangova, Maria, E-mail: mdrangov@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); White, James A., E-mail: jwhite@imaging.robarts.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Lawson Health Research Institute, London, Ontario (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada)

    2012-08-15

    Background: Visual determination of left ventricular ejection fraction (LVEF) by segmental scoring may be a practical alternative to volumetric analysis of cine magnetic resonance imaging (MRI). The accuracy and reproducibility of this approach for has not been described. The purpose of this study was to validate a novel segmental visual scoring method for LVEF estimation using cine MRI. Methods: 362 patients with known or suspected cardiomyopathy were studied. A modified wall motion score (mWMS) was used to blindly score the wall motion of all cardiac segments from cine MRI imaging. The same datasets were subjected to blinded volumetric analysis using endocardial contour tracing. The population was then separated into a model cohort (N = 181) and validation cohort (N = 181), with the former used to derive a regression equation of mWMS versus true volumetric LVEF. The validation cohort was then used to test the accuracy of this regression model to estimate the true LVEF from a visually determined mWMS. Reproducibility testing of mWMS scoring was performed upon a randomly selected sample of 20 cases. Results: The regression equation relating mWMS to true LVEF in the model cohort was: LVEF = 54.23 - 0.5761 Multiplication-Sign mWMS. In the validation cohort this equation produced a strong correlation between mWMS-derived LVEF and true volumetric LVEF (r = 0.89). Bland and Altman analysis showed no systematic bias in the LVEF estimated using the mWMS (-0.3231%, 95% limits of agreement -12.22% to 11.58%). Inter-observer and intra-observer reproducibility was excellent (r = 0.93 and 0.97, respectively). Conclusion: The mWMS is a practical tool for reporting regional wall motion and provides reproducible estimates of LVEF from cine MRI.

  12. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  13. Fluctuating wall shear stress and velocity measurements in a turbulent boundary layer

    Science.gov (United States)

    Pabon, Rommel; Ukeiley, Lawrence; Barnard, Casey; Sheplak, Mark

    2014-11-01

    Knowledge of mean wall shear stress on a surface can shed light on important performance parameters, but the fluctuating shear, even in simple flows, has not been as easily measured, and can be of interest in fundamental boundary layer research. Experiments on a flat plate model were performed to investigate the relationship between the wall shear stress and large scale events in the turbulent boundary layer. A MEMS based differential capacitance shear stress system with 1 mm × 1 mm floating element which can measure the fluctuating and static components of shear simultaneously, coupled with a hot wire anemometer were used for characterizing the turbulent boundary layer. Velocity profiles and turbulence statistics approaching the wall characterized the two dimensionality of the flat plate, and a trailing edge flap was used to impose a zero pressure gradient. The mean streamwise velocity profile was scaled by the friction velocity using the measured shear stress and independently compared to classical fits. Correlations between the fluctuating shear and measured velocities were used to elucidate the large scale events and to compare with previous fluctuating shear measurements for validation.

  14. Effect of mental stress on left ventricular ejection fraction and its relationship to the severity of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Toru; Kuwabara, Yoichi; Watanabe, Satoshi; Nakaya, Jiro; Hasegawa, R.; Shikama, Takeshi; Matsuno, Kouki; Mikami, Yuji; Fujii, Kiyotaka; Saito, Toshihiro; Masuda, Yoshiaki [Dept. of Internal Medicine, Chiba Univ. (Japan)

    2000-12-01

    To evaluate the relationship between the mental stress-induced decrease in left ventricular ejection fraction (LVEF) and the severity of exercise-induced ischaemia, 20 patients with stable coronary artery disease (CAD) underwent radionuclide ventriculography during mental stress testing and stress myocardial perfusion single-photon emission tomography (SPET). We also examined whether changes in haemodynamic and neurohormonal parameters are related to changes in LVEF during mental stress. The LVEF decreased from 54.8%{+-}17.7% to 49.8%{+-}16.2% with mental stress (P<0.0005). Ten of the 20 patients (50.0%) had a {>=}5% decrease in LVEF. The remaining ten patients had no or a <5% decrease in LVEF. There was a significant correlation between the change in LVEF during mental stress and the size of the reversible defect on stress myocardial perfusion SPET (r=-0.80, P<0.0005), with close regional correspondence (75% identical). This correlation was less strong in the 12 patients with a total defect score at rest of <10 (r=-0.69, P=0.014) than in the eight patients with a total defect score at rest of {>=}10 (r=-0.94, P=0.001). The changes in blood pressure and heart rate were not significantly correlated with the change in LVEF, but the percent change in adrenaline concentration correlated with the change in LVEF. It is suggested that mental stress impairs systolic function by inducing transient myocardial ischaemia. The effect of neurohormonal responses during mental stress on LV systolic function may also be important in patients with CAD. (orig.)

  15. Where is the exact origin of narrow premature ventricular contractions manifesting qR in inferior wall leads?

    Science.gov (United States)

    Zheng, Cheng; Li, Jin; Lin, Jia-Xuan; Wang, Lu-Ping; Lin, Jia-Feng

    2016-04-04

    In recent years, radiofrequency catheter ablation(RFCA) has been established as an effective therapy for idiopathic premature ventricular contractions (PVCs), however, its effect on the narrow PVCs (QRS duration qR pattern in inferior leads, may not been fully concluded. Characteristics of 12-lead electrocardiogram (ECG) and electrophysiologic recordings were analyzed in 40 patients with symptomatic PVCs manifesting narrow QRS complex with qR pattern in inferior leads. The procedure of RFCA was performed based on pace mapping and activation mapping. Among the 40 patients with narrow PVCs, complete elimination of PVCs was achieved by RFCA in 35 patients during a median follow-up period of 23 months. Successful ablation was achieved on 19 patients at the sites where earliest Purkinje potentials were recorded in left ventricular anterosuperior septum, thus PVCs arising from left anterior fascicle (LAF) were confirmed, for these PVCs, the QRS morphology were right bundle branch and left posterior fascicle block (RBBB + LPFB) with rightward axis, the average QRS duration 116.07 ± 7.96 ms, R or rsR'in lead V1,with transition zone ahead of lead V1 in precordial leads. Another 16 successful RFCA were achieved by energy delivery at interleaflet triangle(ILT) between right coronary cusp(RCC) and left coronary cusp(LCC) where no Purkinje potentials were recorded, for narrow PVCs arising from the L-RCC ILT, the QRS morphology were similar to the PVCs arising from LAF but much narrower in QRS duration (100.44 ± 3.49 vs. 116.07 ± 7.96 ms, p qR pattern in inferior leads can be cured by the procedure of RFCA. On the basis of our study, we proposed that for narrow PVCs presenting qR pattern in inferior leads, when the ablation procedure failed at proximity of LAF within left anterosuperior septum, mapping and ablation in L-RCC ILT can be tried. The present findings can be helpful for planning catheter ablation for narrow PVCs manifesting qR in inferior leads.

  16. The significance of post-stress decrease in left ventricular ejection fraction in patients undergoing regadenoson stress gated SPECT myocardial perfusion imaging.

    Science.gov (United States)

    Gomez, Javier; Golzar, Yasmeen; Fughhi, Ibtihaj; Olusanya, Adebayo; Doukky, Rami

    2017-02-08

    The significance of post-stress decrease in left ventricular ejection fraction (LVEF) with regadenoson stress gated SPECT (GSPECT) myocardial perfusion imaging (MPI) has not been studied. Consecutive patients who underwent rest/regadenoson stress GSPECT-MPI followed by coronary angiography within 6 months were analyzed. Change in LVEF by GSPECT-MPI was calculated as stress LVEF minus rest LVEF; a significant decrease was tested at 5% and 10% thresholds. In a diagnostic cohort of 793 subjects, LVEF change was not predictive of severe/extensive coronary artery disease (area under the curve, 0.50; 95% confidence interval, 0.44-0.57; P = 0.946). There was no significant difference in the rates of severe/extensive coronary artery disease in patients with or without a decrease in LVEF, irrespective of MPI findings. In an outcome cohort of the 929 subjects followed for 30 ± 16 months, post-regadenoson stress decrease in LVEF was not associated with increased risk of the composite endpoint of cardiac death or myocardial infarction or in the risk of coronary revascularization. In patients selected to undergo coronary angiography following regadenoson stress GSPECT-MPI, a decrease in LVEF after regadenoson stress is not predictive of severe/extensive CAD or adverse clinical outcomes, irrespective of MPI findings.

  17. Effect of Heat Flux on Creep Stresses of Thick-Walled Cylindrical Pressure Vessels

    Directory of Open Access Journals (Sweden)

    Mosayeb Davoudi Kashkoli

    2014-06-01

    Full Text Available Assuming that the thermo-creep response of the material is governed by Norton’s law, an analytical solution is presented for the calculation of time-dependent creep stresses and displacements of homogeneous thick-walled cylindrical pressure vessels. For the stress analysis in a homogeneous pressure vessel, having material creep behavior, the solutions of the stresses at a time equal to zero (i.e. the initial stress state are needed. This corresponds to the solution of materials with linear elastic behavior. Therefore, using equations of equilibrium, stress-strain and strain-displacement, a differential equation for displacement is obtained and then the stresses at a time equal to zero are calculated. Using Norton’s law in the multi-axial form in conjunction with the above-mentioned equations in the rate form, the radial displacement rate is obtained and then the radial, circumferential and axial creep stress rates are calculated. When the stress rates are known, the stresses at any time are calculated iteratively. The analytical solution is obtained for the conditions of plane strain and plane stress. The thermal loading is as follows: inner surface is exposed to a uniform heat flux, and the outer surface is exposed to an airstream. The heat conduction equation for the one-dimensional problem in polar coordinates is used to obtain temperature distribution in the cylinder. The pressure, inner radius and outer radius are considered constant. Material properties are considered as constant. Following this, profiles are plotted for the radial displacements, radial stress, circumferential stress and axial stress as a function of radial direction and time.

  18. An inverse finite element method for determining the tissue compressibility of human left ventricular wall during the cardiac cycle.

    Science.gov (United States)

    Hassaballah, Abdallah I; Hassan, Mohsen A; Mardi, Azizi N; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium's tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle.

  19. An inverse finite element method for determining the tissue compressibility of human left ventricular wall during the cardiac cycle.

    Directory of Open Access Journals (Sweden)

    Abdallah I Hassaballah

    Full Text Available The determination of the myocardium's tissue properties is important in constructing functional finite element (FE models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility, as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle.

  20. An Inverse Finite Element Method for Determining the Tissue Compressibility of Human Left Ventricular Wall during the Cardiac Cycle

    Science.gov (United States)

    Hassaballah, Abdallah I.; Hassan, Mohsen A.; Mardi, Azizi N.; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium’s tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle. PMID:24367544

  1. Impact of Wall Shear Stress and Pressure Variation on the Stability of Atherosclerotic Plaque

    Science.gov (United States)

    Taviani, V.; Li, Z. Y.; Sutcliffe, M.; Gillard, J.

    Rupture of vulnerable atheromatous plaque in the carotid and coronary arteries often leads to stroke and heart attack respectively. The mechanism of blood flow and plaque rupture in stenotic arteries is still not fully understood. A three dimensional rigid wall model was solved under steady and unsteady conditions assuming a time-varying inlet velocity profile to investigate the relative importance of axial forces and pressure drops in arteries with asymmetric stenosis. Flow-structure interactions were investigated for the same geometry and the results were compared with those retrieved with the corresponding one dimensional models. The Navier-Stokes equations were used as the governing equations for the fluid. The tube wall was assumed linearly elastic, homogeneous isotropic. The analysis showed that wall shear stress is small (less than 3.5%) with respect to pressure drop throughout the cycle even for severe stenosis. On the contrary, the three dimensional behavior of velocity, pressure and wall shear stress is in general very different from that predicted by one dimensional models. This suggests that the primary source of mistakes in one dimensional studies comes from neglecting the three dimensional geometry of the plaque. Neglecting axial forces only involves minor errors.

  2. Characterization of applied tensile stress using domain wall dynamic behavior of grain-oriented electrical steel

    Science.gov (United States)

    Qiu, Fasheng; Ren, Wenwei; Tian, Gui Yun; Gao, Bin

    2017-06-01

    Stress measurement that provides early indication of stress status has become increasingly demanding in the field of Non-destructive testing and evaluation (NDT&E). Bridging the correlation between micro magnetic properties and the applied tensile stress is the first conceptual step to come up with a new method of non-destructive testing. This study investigates the characterization of applied tensile stress with in-situ magnetic domain imaging and their dynamic behaviors by using magneto-optical Kerr effect (MOKE) microscopy assisted with magneto-optical indicator film (MOIF). Threshold magnetic field (TMF) feature to reflect 180 ° domain wall (DW) characteristics behaviors in different grains is proposed for stress detection. It is verified that TMF is a threshold feature with better sensitivity and brings linear correlation for stress characterization in comparison to classical coercive field, remanent magnetization, hysteresis loss and permeability parameters. The results indicate that 180 ° DWs dynamic in the inner grain is highly correlated with stress. The DW dynamics of turn over (TO) tests for different grains is studied to illustrate the repeatability of TMF. Experimental tests of high permeability grain oriented (HGO) electrical steels under stress loading have been conducted to verify this study.

  3. Immunological and inflammatory processes in systemic autoimmune disease may not only cause pericardium inflammation, but may also cause mitral valve deterioration and left ventricular wall thickening.

    Science.gov (United States)

    Sugiura, Atsushi; Funabashi, Nobusada; Ozawa, Koya; Kobayashi, Yoshio

    2016-07-15

    Systemic autoimmune disease (SAD) frequently affects the pericardium, and pathology is characterized by both immunological and inflammatory processes. We hypothesized that these processes simultaneously influence mitral-valve (MV) deterioration and left-ventricular (LV) wall thickening in SAD subjects. 101 SAD subjects were selected (76 female; 53±17years; systemic-lupus-erythematosus, 26%; vasculitis, 20%; scleroderma, 14%; polymyositis/dermatomyositis complex, 10%; mixed connective tissue disease, 11% and rheumatoid-arthritis, 2%). MV anterior-mitral-leaflet (AML) length, AML thickness index, AML doming height and LV mass index (LVMI) were measured using transthoracic-echocardiography (TTE) and the presence of MV calcification, MV sub-valvular thickening and pericardial effusion (PE) were estimated. AML thickness index was calculated as the ratio of AML thickness to aortic posterior wall thickness. The correlation between LVMI and ECG V1S+V5R voltage was used to assess the etiology of LV wall thickening. 19 subjects (19%) had significant PE. PE subjects had a significantly greater AML thickness index (1.55±0.48 vs. 1.14±0.32, P<0.001), AML doming height (1.26±1.54mm vs. 0.03±0.91mm, P<0.001), more frequent MV sub-valvular thickening (26% vs. 5%, P=0.003) and greater LVMI (104.7±34.6g/m2 vs. 80.6±21.0g/m2, P=0.002). Significant correlation was observed between LVMI and ECG V1S+V5R voltage in 79 subjects without PE (R=0.39, P<0.001). However, in 18 subjects with PE, no such correlation was observed (R=0.30, P=0.23). MV, MV sub-valvular deterioration and increased LVMI, unrelated to high voltage ECG criteria, were frequently detected in SAD subjects with PE. Immunological and inflammatory processes in SAD may not only cause pericardium inflammation, but may also cause MV deterioration and LV wall thickening. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Tunnel Propagation Following Defibrillation with ICD Shocks: Hidden Postshock Activations in the Left Ventricular Wall Underlie Isoelectric Window

    Science.gov (United States)

    Constantino, Jason; Long, Yun; Ashihara, Takashi; Trayanova, Natalia A.

    2010-01-01

    Background Following near-defibrillation threshold (DFT) shocks from an ICD, the first postshock activation that leads to defibrillation failure arises focally after an isolelectric window (IW). The mechanisms underlying the IW remain incompletely understood. Objective The goal of this study was to provide mechanistic insight into the origins of postshock activations and IW following ICD shocks, and to link shock outcome to the preshock state of the ventricles. We hypothesized that the non-uniform ICD field results in the formation of an intramural excitable area (tunnel) only in the LV free wall, through which both pre-existing and new shock-induced wavefronts propagate during the IW. Methods Simulations were conducted using a realistic 3-D model of defibrillation in the rabbit ventricles. Biphasic ICD shocks of varying strengths were delivered to 27 different fibrillatory states. Results Following near-DFT shocks, regardless of preshock state, the main postshock excitable area was always located within LV free wall, creating an intramural tunnel. Either preexisting fibrillatory or shock-induced wavefronts propagated during the IW (duration of up to 74ms) in this tunnel and emerged as breakthroughs on LV epicardium. Preshock activity within the LV played a significant role in shock outcome: large number of preshock filaments resulted in an IW associated with tunnel propagation of preexisting rather than shock-induced wavefronts. Furthermore, shocks were more likely to succeed if LV excitable area was smaller. Conclusions The LV intramural excitable area is the primary reason for near-DFT failure. Any intervention that decreases the extent of this area will improve the likelihood of defibrillation success. PMID:20348028

  5. A computer graphic-based angiographic model for normal left ventricular contraction in man and its application to the detection of abnormalities in regional wall motion.

    Science.gov (United States)

    Shepertycki, T H; Morton, B C

    1983-12-01

    Analyzing the digitized left ventricular cineangiograms of 70 patients with no demonstrable heart disease (NDHD), we derived an angiographic model for normal contraction in the intact heart as viewed in the 30 degree right anterior oblique projection. This model was verified statistically by comparing the predicted regional stroke volumes with the measured volumes for the NDHD group. A wall motion system based on this model was compared with four other systems by examining the ventriculograms of 141 patients, all suffering from coronary artery disease but with normal volumes and ejection fractions (greater than 0.61). Of these, 60 had normally contracting ventricles and 81 exhibited mild regional abnormalities according to two experienced angiographers. Using Cochrane's Q test, we found significant differences among the five methods (Q = 29.5;p less than .001). The new approach showed significantly better agreement with the subjective assessment than the next best method (Q = 5.3;p less than .05). On a regional basis, overall sensitivity was 87.5% and specificity was 97.9%.

  6. Oscillatory motion based measurement method and sensor for measuring wall shear stress due to fluid flow

    Science.gov (United States)

    Armstrong, William D [Laramie, WY; Naughton, Jonathan [Laramie, WY; Lindberg, William R [Laramie, WY

    2008-09-02

    A shear stress sensor for measuring fluid wall shear stress on a test surface is provided. The wall shear stress sensor is comprised of an active sensing surface and a sensor body. An elastic mechanism mounted between the active sensing surface and the sensor body allows movement between the active sensing surface and the sensor body. A driving mechanism forces the shear stress sensor to oscillate. A measuring mechanism measures displacement of the active sensing surface relative to the sensor body. The sensor may be operated under periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor measurably changes the amplitude or phase of the motion of the active sensing surface, or changes the force and power required from a control system in order to maintain constant motion. The device may be operated under non-periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor change the transient motion of the active sensor surface or change the force and power required from a control system to maintain a specified transient motion of the active sensor surface.

  7. Growth promoting effects of prebiotic yeast cell wall products in starter broilers under an immune stress and Clostridium perfringens challenge

    Science.gov (United States)

    This study was designed to investigate the growth promoting effects of supplementing different sources and concentrations of prebiotic yeast cell wall (YCW) products containing mannanoligosaccharides in starter broilers under an immune stress and Clostridium perfringens challenge. Through a series ...

  8. Multilayer radial systolic strain can identify subendocardial ischemia: an experimental tissue Doppler imaging study of the porcine left ventricular wall.

    Science.gov (United States)

    Matre, Knut; Moen, Christian Arvei; Fanneløp, Tord; Dahle, Geir Olav; Grong, Ketil

    2007-12-01

    This study investigates whether subendocardial ischemia can be detected by measuring multilayer radial systolic strain from epicardial tissue Doppler imaging. In 10 anesthetized open-chest pigs an extracorporeal shunt from the proximal brachiocephalic to the left anterior descending coronary artery was constricted in steps. Color microsphere injections and short axis Tissue Velocity Imaging (TVI) recordings were performed with open shunt, with a non-significant stenosis, and with 2 steps of shunt flow reduction. With open shunt and no transmural flow gradient, there was a gradient of peak ejection strain with high values subendocardially for both 4 and 2 layer measurements. For 2 layer measurement strain was 56.0+/-10.5% subendocardially and 22.0+/-5.2% subepicardially. A non-significant stenosis, not altering transmural flow distribution, reduced strain to 40.3+/-5.4% in the endocardial half-layer. With reduced shunt flow resulting in subendocardial ischemia, peak ejection strain decreased further, primarily in inner wall layers, and postsystolic strain became evident. At severe stenosis (52.4+/-1.8% shunt flow reduction) strain was reduced to 3.8+/-3.6% in the subendocardium and 0.0+/-2.6% in the subepicardium. Evaluation of myocardial function with multilayer radial systolic strain has a potential for detecting subendocardial ischemia.

  9. Wall shear stress characterization of a 3D bluff-body separated flow

    Science.gov (United States)

    Fourrié, Grégoire; Keirsbulck, Laurent; Labraga, Larbi

    2013-10-01

    Efficient flow control strategies aimed at reducing the aerodynamic drag of road vehicles require a detailed knowledge of the reference flow. In this work, the flow around the rear slanted window of a generic car model was experimentally studied through wall shear stress measurements using an electrochemical method. The mean and fluctuating wall shear stress within the wall impact regions of the recirculation bubble and the main longitudinal vortex structures which develop above the rear window are presented. Correlations allow a more detailed characterization of the recirculation phenomenon within the separation bubble. In the model symmetry plane the recirculation structure compares well with simpler 2D configurations; specific lengths, flapping motion and shedding of large-scale vortices are observed, these similarities diminish when leaving the middle plane due to the strong three-dimensionality of the flow. A specific attention is paid to the convection processes occurring within the recirculation: a downstream convection velocity is observed, in accordance with 2D recirculations from the literature, and an upstream convection is highlighted along the entire bubble length which has not been underlined in some previous canonical configurations.

  10. The Aspergillus niger MADS-box transcription factor RlmA is required for cell wall reinforcement in response to cell wall stress

    NARCIS (Netherlands)

    Damveld, R.A.; Arentshorst, M.; Franken, A.; Kuyk, P.A. van; Klis, F.M.; Hondel, C.A.M.J.J. van den; Ram, A.F.J.

    2005-01-01

    In Aspergillus niger, the genes coding for glutamine:fructose-6-phosphate amidotransferase (gfaA) and α-1,3-glucan synthase (agsA) are induced in response to cell wall stress. In silico analysis of the promoter region of the two genes revealed the presence of putative DNA binding sites for

  11. Photo elastic analysis of stresses in the root canal walls around double taper and

    Directory of Open Access Journals (Sweden)

    Zafar Mahdavi Ezadi

    2013-10-01

    Full Text Available   Background and Aims : According to the common application of non-metal prefabricated posts in dentistry and lack of enough information about the stress distribution in the root canal walls by these posts, this study was performed to compare the effect of two simple taper and double taper posts on the stress distribution on root canal walls by photo elastic method .   Materials and Methods: The design of this study was experimental in photoelastic system. The posts, used in this investigation, were double taper and simple taper fiber posts with 0.9 mm diameter and 20 mm length and epoxy resin. First two photo elastic models with tooth dimensions were fabricated and the posts were placed inside the model. Then the core of the each post was fabricated on the model. Each models were loaded in polariscope and the formed fringe order colored ring were photographed.   Results: In 100 N, 90 degree angle loading in cervical and apical fringe order showed 2.50 and 1.39 in simple taper posts and 1.39 and 2.35 in double taper post. In 150 N, 30 degree angle loading in cervical and apical fringe order showed 4 and 2.65 in simple taper posts, and 4 and 2.5 in double taper post.   Conclusion: In the vertical and oblique loads, double taper fiber post showed better stress distribution than that of simple tapered posts.

  12. Cell wall pectic arabinans influence the mechanical properties of Arabidopsis thaliana inflorescence stems and their response to mechanical stress.

    Science.gov (United States)

    Verhertbruggen, Yves; Marcus, Susan E; Chen, Jianshe; Knox, J Paul

    2013-08-01

    Little is known of the dynamics of plant cell wall matrix polysaccharides in response to the impact of mechanical stress on plant organs. The capacity of the imposition of a mechanical stress (periodic brushing) to reduce the height of the inflorescence stem of Arabidopsis thaliana seedlings has been used to study the role of pectic arabinans in the mechanical properties and stress responsiveness of a plant organ. The arabinan-deficient-1 (arad1) mutation that affects arabinan structures in epidermal cell walls of inflorescence stems is demonstrated to reduce the impact on inflorescence stem heights caused by mechanical stress. The arabinan-deficient-2 (arad2) mutation, that does not have detectable impact on arabinan structures, is also shown to reduce the impact on stem heights caused by mechanical stress. The LM13 linear arabinan epitope is specifically detected in epidermal cell walls of the younger, flexible regions of inflorescence stems and increases in abundance at the base of inflorescence stems in response to an imposed mechanical stress. The strain (percentage deformation) of stem epidermal cells in the double mutant arad1 × arad2 is lower in unbrushed plants than in wild-type plants, but rises to wild-type levels in response to brushing. The study demonstrates the complexity of arabinan structures within plant cell walls and also that their contribution to cell wall mechanical properties is a factor influencing responsiveness to mechanical stress.

  13. Effects of dynamic shear and transmural pressure on wall shear stress sensitivity in collecting lymphatic vessels.

    Science.gov (United States)

    Kornuta, Jeffrey A; Nepiyushchikh, Zhanna; Gasheva, Olga Y; Mukherjee, Anish; Zawieja, David C; Dixon, J Brandon

    2015-11-01

    Given the known mechanosensitivity of the lymphatic vasculature, we sought to investigate the effects of dynamic wall shear stress (WSS) on collecting lymphatic vessels while controlling for transmural pressure. Using a previously developed ex vivo lymphatic perfusion system (ELPS) capable of independently controlling both transaxial pressure gradient and average transmural pressure on an isolated lymphatic vessel, we imposed a multitude of flow conditions on rat thoracic ducts, while controlling for transmural pressure and measuring diameter changes. By gradually increasing the imposed flow through a vessel, we determined the WSS at which the vessel first shows sign of contraction inhibition, defining this point as the shear stress sensitivity of the vessel. The shear stress threshold that triggered a contractile response was significantly greater at a transmural pressure of 5 cmH2O (0.97 dyne/cm(2)) than at 3 cmH2O (0.64 dyne/cm(2)). While contraction frequency was reduced when a steady WSS was applied, this inhibition was reversed when the applied WSS oscillated, even though the mean wall shear stresses between the conditions were not significantly different. When the applied oscillatory WSS was large enough, flow itself synchronized the lymphatic contractions to the exact frequency of the applied waveform. Both transmural pressure and the rate of change of WSS have significant impacts on the contractile response of lymphatic vessels to flow. Specifically, time-varying shear stress can alter the inhibition of phasic contraction frequency and even coordinate contractions, providing evidence that dynamic shear could play an important role in the contractile function of collecting lymphatic vessels. Copyright © 2015 the American Physiological Society.

  14. Transient Left Ventricular Contractile Dysfunction during the Treatment of Rhabdomyolysis: A Case Report and Literature Review

    Science.gov (United States)

    Tsuruda, Toshihiro; Shinohara, Nozomi; Ogata, Miyuki; Kitamura, Kazuo; Ochiai, Hidenobu

    2017-01-01

    Transient left ventricular contractile dysfunction (TLVCD) is often observed as a result of stress-related cardiomyopathy; however, recent reports suggest that rhabdomyolysis and eating disorders can also induce the development of TLVCD. We report a 52-year-old malnourished man who developed acute heart failure on day 4 of treatment for rhabdomyolysis. Transthoracic echocardiogram revealed severe hypokinesis at the apical and mid-ventricular segments, except for the basal segments of the left ventricular wall, which recovered within one week. We discuss the pathogenesis of TLVCD with sympathetic nerve activation in association with rhabdomyolysis or refeeding syndrome. PMID:28924116

  15. Impact of Remote Ischemic Postconditioning during Primary Percutaneous Coronary Intervention on Left Ventricular Remodeling after Anterior Wall ST-Segment Elevation Myocardial Infarction: A Single-Center Experience.

    Science.gov (United States)

    Elbadawi, Ayman; Awad, Omar; Raymond, Ramy; Badran, Haytham; Mostafa, Ahmad E; Saad, Marwan

    2017-12-01

    The role of remote ischemic postconditioning (RIPostC) in improving left ventricular (LV) remodeling after primary percutaneous coronary intervention (PCI) is not well established. To determine the efficacy and safety of RIPostC in improving LV remodeling and cardiovascular outcomes after primary PCI for anterior ST-elevation myocardial infarction (STEMI). Seventy-one patients with anterior STEMI were randomized to primary PCI with RIPostC protocol ( n  = 36) versus conventional primary PCI ( n  = 35). Primary outcomes included LV remodeling and LV ejection fraction (LVEF) at 6 month follow-up using transthoracic echocardiography. Secondary outcomes included infarct size, ST-segment resolution (STR) ≥70%, Thrombolysis in Myocardial Infarction (TIMI) flow grade, and myocardial blush grade (MBG). Major adverse cardiac events (MACEs) were also assessed at 6 months. Safety outcome included incidence of acute kidney injury (AKI) postprimary PCI. Sixty patients completed the study. At 6 months, there was no significant decrease in the incidence of LV remodeling with RIPostC group ( p  = 0.42). Similarly, RIPostC failed to show significant improvement in LVEF. However, STR ≥ 70% after primary PCI was achieved more in the RIPostC group ( p  = 0.04), with a trend toward less AKI in the RIPostC group ( p  = 0.08). All other secondary end points, including MACEs at 6 months, were similar in both groups. RIPostC might be associated with better STR after reperfusion as well as less incidence of AKI in patients undergoing primary PCI for anterior wall STEMI, indicating potential benefit in those patients. Whether this role can be translated to better outcomes after primary PCI warrants further investigation.

  16. Effects of verapamil, carbenoxolone and N-acetylcysteine on gastric wall mucus and ulceration in stressed rats.

    Science.gov (United States)

    Koo, M W; Ogle, C W; Cho, C H

    1986-01-01

    The effects of verapamil on gastric wall mucus and ulceration were studied in rats which were restrained and exposed to 4 degrees C (stress). Stress for 2 h significantly depleted stomach wall mucus and produced marked gastric glandular ulcers. Verapamil pretreatment (2, 4, 8 or 16 mg/kg), injected intraperitoneally 30 min before experimentation, significantly prevented stress-induced mucus depletion and gastric ulceration; however, it did not itself influence stomach wall mucus levels in nonstressed animals. Intragastric administration of carbenoxolone (100 or 200 mg/kg), also given 30 min before stress, exhibited similar actions as verapamil. A 15% solution of N-acetylcysteine (10 ml/kg), given orally, strongly decreased the mucus content in both nonstress and stress conditions; it induced ulcers in nonstressed rats, and worsened stress ulceration. These effects were not reversed by verapamil pretreatment. The influence of multiple-dose pretreatment with verapamil or carbenoxolone on mucus content and ulceration in the gastric glandular mucosa during stress is also discussed. It is concluded that gastric wall mucus depletion is likely to play an important role in stress ulcer formation; the antiulcer action of verapamil could partly be due to the preservation of mucus.

  17. Experimental study on the Reynolds and viscous shear stress of bileaflet mechanical heart valves in a pneumatic ventricular assist device.

    Science.gov (United States)

    Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2009-01-01

    Our group is currently developing a pneumatic ventricular assist device (PVAD). In general, the major causes of hemolysis in a pulsatile VAD are cavitation, and Reynolds shear stress (RSS) in the mechanical heart valve (MHV). In a previous study, we investigated MHV cavitation. To select the optimal bileaflet valve for our PVAD, in the current study, we investigated RSS and viscous shear stress (VSS) downstream of three different types of commercial bileaflet valves by means of 2D particle image velocimetry (PIV). To carry out flow visualization inside the blood pump and near the valve, we designed a model pump with the same configuration as that of our PVAD. Three types of bileaflet valves (i.e., the ATS valve, the St. Jude valve, and the Sorin Bicarbon valve) were mounted at the aortic position of the model pump, and flow was visualized according to the PIV method. The maximum flow velocity and RSS of the Sorin Bicarbon valve were lower than those of the other two bileaflet valves. The maximum VSS was only 1% of the maximum RSS. Thus, the effect of VSS on blood cell trauma was neglected. The Sorin Bicarbon valve exhibited relatively low levels of RSS, and was therefore considered to be the best valve for our PVAD among the three valves tested.

  18. 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

  19. 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.

  20. Pressor hormone profile during stress in hypertension: does vasopressin interfere with left ventricular hypertrophy?

    Science.gov (United States)

    Manolis, A; Athanasopoulos, G; Karatasakis, G; Gavras, I; Bresnahan, M; Cokkinos, D V; Gavras, H

    1993-05-01

    Neurohormonal factors may account for the fact that patients with similar severity and duration of hypertension develop different degrees of left ventricular hypertrophy (LVH). The purpose of this work was to compare the pressor hormone profiles of hypertensive subjects off medication during exercise testing. Nineteen patients, stratified according to echocardiographically diagnosed absence (Group I n = 6) or presence (Group II n = 13) of LVH, underwent testing on the treadmill according to the Bruce protocol. Both groups were comparable in age, severity and duration of hypertension and reached similar double product at peak exercise. Measurements of plasma renin activity (PRA), plasma catecholamines and vasopressin (AVP) at baseline, peak exercise and post exercise revealed significant differences between groups: Group I had suppressed PRA levels throughout and had significantly higher baseline AVP levels, which increased further at peak effort. Group II had significantly higher baseline PRA levels, which tended to increase further at peak effort, and had suppressed AVP levels throughout. There was a significant negative correlation between percent increments in AVP and increments in double product. Norepinephrine increased significantly with effort in both groups, but the levels attained were higher in Group I. In view of the known negative inotropic action of AVP and the trophic effect of angiotensin, we speculate that lower baseline AVP and higher PRA, together with inability of AVP to increase with effort, may be causally related to development of LVH.

  1. Stress adapted embroidered meshes with a graded pattern design for abdominal wall hernia repair

    Science.gov (United States)

    Hahn, J.; Bittrich, L.; Breier, A.; Spickenheuer, A.

    2017-10-01

    Abdominal wall hernias are one of the most relevant injuries of the digestive system with 25 million patients in 2013. Surgery is recommended primarily using allogenic non-absorbable wrap-knitted meshes. These meshes have in common that their stress-strain behaviour is not adapted to the anisotropic behaviour of native abdominal wall tissue. The ideal mesh should possess an adequate mechanical behaviour and a suitable porosity at the same time. An alternative fabrication method to wrap-knitting is the embroidery technology with a high flexibility in pattern design and adaption of mechanical properties. In this study, a pattern generator was created for pattern designs consisting of a base and a reinforcement pattern. The embroidered mesh structures demonstrated different structural and mechanical characteristics. Additionally, the investigation of the mechanical properties exhibited an anisotropic mechanical behaviour for the embroidered meshes. As a result, the investigated pattern generator and the embroidery technology allow the production of stress adapted mesh structures that are a promising approach for hernia reconstruction.

  2. A multi-layer description of Reynolds stresses in canonical wall bounded flows

    Science.gov (United States)

    Chen, Xi; Hussain, Fazle; She, Zhen-Su

    2015-11-01

    A complete description of the Reynolds stress tensor is obtained for all three canonical wall turbulence (channel, pipe and turbulent boundary layer - TBL). The result builds on a multi-layer description of length (order) functions and their ratios, including viscous sublayer, buffer layer, meso-layer for the near wall (inner) region, and bulk flow or a central core (absent in TBL) for the outer region. It is shown that the streamwise mean kinetic-energy profile is quantified with high accuracy over the entire flow domain. The model contains only three Re-dependent parameters for Reynolds number (Re) covering nearly three decades. Furthermore, the inner peak location is predicted to be invariant at y+ = 15, while its magnitude shows notable Re and geometry effects, predicted to be .9.2 for high Re's pipe flows. A mechanism is proposed for the emergence of outer peak in pipes, whose magnitude is predicted to scale as .Reτ0. 05 beyond a critical Reτ about 104(). The recently reported logarithmic dependence in the bulk is recovered, but with an alternative explanation. The result is successfully extended to TBL flows by a fractional total stress and an absence of core. Equally accurate descriptions of vertical and spanwise kinetic-energy are also presented for the three flows. The result has been used to modify turbulent engineering models (i.e. k- ω model) with significant improvement.

  3. Nonoperative Treatment of Posterior Wall Acetabular Fractures After Dynamic Stress Examination Under Anesthesia: Revisited.

    Science.gov (United States)

    McNamara, Andrew R; Boudreau, John A; Moed, Berton R

    2015-08-01

    Performing an examination under general anesthesia (EUA) using dynamic stress fluoroscopy of patients with posterior wall acetabular fractures has been used as a tool to determine hip stability and the need for surgical intervention. The purpose of this study was to further evaluate the effectiveness of this technique, from a source other than its primary advocates, in patients with posterior wall acetabular fractures less than or equal to 50% who were stable on EUA and treated nonoperatively. Retrospective case series. University Level 1 Trauma Center. Seventeen patients with a posterior wall acetabular fracture stable on EUA treated nonoperatively. The patients were treated nonoperatively as guided by an EUA negative for instability. Patient follow-up averaged 30 months (range, 6-64 months). Outcome evaluation included the modified Merle d'Aubigné clinical score and the Short Musculoskeletal Function Assessment Questionnaire. Radiographic evaluation for subluxation or arthritis consisted of the 3 standard pelvic radiographs. Radiographic evaluation showed all hips to be congruent with a normal joint space. Sixteen of the 17 patients had radiographic outcomes rated as "excellent"; 1 patient was rated "good." The modified Merle d'Aubigné score (obtained in 12 patients) averaged very good, with only 1 having less than a good (graded as fair) clinical outcome. The Short Musculoskeletal Function Assessment Questionnaire scores (from 11 patients) were not significantly different from normal and were within the normal reported values for all indices and categories. There was no correlation between fracture fragment size and outcome. This study further supports the contention that a stable hip joint, as determined by EUA, after posterior wall acetabular fracture treated nonoperatively is predictive of continued joint congruity, an excellent radiographic outcome, and good-to-excellent early clinical and functional outcomes. Therapeutic Level IV. See Instructions for

  4. Takotsubo or Stress Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    J. P. Bounhoure

    2012-01-01

    Full Text Available Many case reports have been published of reversible left ventricular dysfunction precipitated by sudden emotional stress. We have evaluated 10 women hospitalized for acute chest pain and dyspnea, mimicking an acute coronary syndrome, after a severe emotional trigger. Those patients, postmenopausal women, presented ST segment alterations on the EKG, minor elevations of cardiac enzymes, and biomarkers levels. At the coronarography there was not coronary thrombosis or severe stenosis, but the ventriculography showed wall motion abnormalities involving the left ventricular apex and midventricle, in the absence of significant obstructive coronary disease. The course was benign without complication, with a full recovery of left ventricular function in some weeks. These observations, like other reports, demonstrate the impact of emotional stress on left ventricular function and the risk of cardiovascular disease. The cause of this cardiomyopathy is still unknown, and several mechanisms have been proposed: catecholamine myocardial damage, microvascular spasm, or neural mediated myocardial stunning.

  5. Detection of perfusion abnormalities in patients with permanent pacemakers on stress-rest 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography: comparison between right ventricular apex and right ventricular outflow tract pacing.

    Science.gov (United States)

    Das, Kalpa J; Patel, Chetan D; Sharma, Gautam; Naik, Nitish; Singh, Harmandeep

    2016-04-01

    The aim of the study was to compare the myocardial perfusion defects in patients with right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing on stress-rest Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography. A total of 31 patients with permanent pacemakers (RVOT: 16 and RVA: 15) underwent stress-rest Tc-tetrofosmin involving a 1-day protocol. All patients underwent 1-day low-dose stress-gated and high-dose rest-gated Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography imaging. Fixed perfusion defects were noted in 13 (42%) of 31 patients. Two (13%) patients of the RVOT group and 11 (69%) patients of the RVA group showed fixed perfusion defects (P=0.003). The fixed perfusion defects were located in the anteroapical, anteroseptal, and apical in the RVOT pacing group and in the apical, distal anteroseptal, inferoapical, distal anterior, and distal inferoseptal in the RVA pacing group. On univariate analysis, the incidence of perfusion defects was significantly associated with apical pacing, longer pQRS duration, and higher percentage of ventricular pacing. On multivariate analysis, the site of pacemaker insertion was found to be the most important pacemaker parameter determining the incidence of perfusion defects. Importantly, the duration of postpacemaker implantation did not show any significant relation to the incidence of perfusion defects. Fixed perfusion abnormalities are observed in patients with pacemakers and are independent of duration of time since implantation. RVOT pacing is associated with fewer incidences of myocardial perfusion abnormalities compared with RVA pacing.

  6. The combined impact of mechanical factors on the wall stress of the human ascending aorta - a finite elements study.

    Science.gov (United States)

    Plonek, Tomasz; Zak, Malgorzata; Burzynska, Karolina; Rylski, Bartosz; Gozdzik, Anna; Kustrzycki, Wojciech; Beyersdorf, Friedhelm; Jasinski, Marek; Filipiak, Jaroslaw

    2017-12-20

    Biomechanical factors influence stress in the aortic wall. The aim of this study was to assess how the diameter and shape of the vessel, blood pressure and longitudinal systolic aortic stretching (SAS) caused by the contraction of the myocardium influence stress in the aortic wall. Three computational models of the non-dilated aorta and aneurysms of the ascending aorta and aortic root were created. Then, finite elements analyses were carried out. The models were subjected to blood pressure (120 mmHg and 160 mmHg) and longitudinal systolic aortic stretching (0 mm, 5 mm, 10 mm and 15 mm). The influence of wall elasticity was examined too. Blood pressure had a smaller impact on the stress than the SAS. An increase in blood pressure from120 mmHg to 160 mmHg increased the peak wall stress (PWS) on average by 0.1 MPa in all models. A 5 mm SAS caused a 0.1–0. 2 MPa increase in PWS in all the models. The increase in PWS caused by a 10mm and 15mmSAS was 0.2 MPa and 0. 4 MPa in the non-dilated aorta, 0.2–0.3 MPa and 0.3–0.5 MPa in the aneurysm of the ascending aorta, and 0.1–0.2 MPa and 0.2–0.3 MPa in the aortic root aneurysm model, respectively. The loss of elasticity of the aneurysmal wall resulted in an increase of PWS by 0.1–0.2 MPa. Aortic geometry, wall stiffness, blood pressure and SAS have an impact on PWS. However, SAS had the biggest impact on wall stress. The results of this study may be useful in future patient-specific computational models used to assess the risk of aortic complications.

  7. Design optimization of scaffold microstructures using wall shear stress criterion towards regulated flow-induced erosion.

    Science.gov (United States)

    Chen, Yuhang; Schellekens, Michiel; Zhou, Shiwei; Cadman, Joseph; Li, Wei; Appleyard, Richard; Li, Qing

    2011-08-01

    Tissue scaffolds aim to provide a cell-friendly biomechanical environment for facilitating cell growth. Existing studies have shown significant demands for generating a certain level of wall shear stress (WSS) on scaffold microstructural surfaces for promoting cellular response and attachment efficacy. Recently, its role in shear-induced erosion of polymer scaffold has also drawn increasing attention. This paper proposes a bi-directional evolutionary structural optimization (BESO) approach for design of scaffold microstructure in terms of the WSS uniformity criterion, by downgrading highly-stressed solid elements into fluidic elements and/or upgrading lowly-stressed fluidic elements into solid elements. In addition to this, a computational model is presented to simulate shear-induced erosion process. The effective stiffness and permeability of initial and optimized scaffold microstructures are characterized by the finite element based homogenization technique to quantify the variations of mechanical properties of scaffold during erosion. The illustrative examples show that a uniform WSS is achieved within the optimized scaffold microstructures, and their architectural and biomechanical features are maintained for a longer lifetime during shear-induced erosion process. This study provides a mathematical means to the design optimization of cellular biomaterials in terms of the WSS criterion towards controllable shear-induced erosion.

  8. Failure Strain and Strain-Stress Analysis in Titanium Nitride Coatings Deposited on Religa Heart Ext Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Kopernik M.

    2015-04-01

    Full Text Available The Polish ventricular assist device is made of Bionate II with deposited TiN biocompatible nano-coating. The two scale finite element model is composed of a macro-model of blood chamber and a micro-model of the TiN/Bionate II. The numerical analysis of stress and strain states confirmed the possibility of fracture. Therefore, the identification of a fracture parameter considered as a failure strain is the purpose of the present work. The tensile test in a micro chamber of the SEM was performed to calibrate the fracture parameter of the material system TiN/Bionate II. The failure strain is a function of a temperature, a thickness of coating and parameters of surface's profile. The failure strain was calculated at the stage of the test, in which the initiation of fracture occurred. The finite element micro-model includes the surface roughness and the failure strain under tension condition for two thicknesses of coatings which will be deposited on the medical device.

  9. Wall shear stress in portal vein of cirrhotic patients with portal hypertension.

    Science.gov (United States)

    Wei, Wei; Pu, Yan-Song; Wang, Xin-Kai; Jiang, An; Zhou, Rui; Li, Yu; Zhang, Qiu-Juan; Wei, Ya-Juan; Chen, Bin; Li, Zong-Fang

    2017-05-14

    To investigate wall shear stress (WSS) magnitude and distribution in cirrhotic patients with portal hypertension using computational fluid dynamics. Idealized portal vein (PV) system models were reconstructed with different angles of the PV-splenic vein (SV) and superior mesenteric vein (SMV)-SV. Patient-specific models were created according to enhanced computed tomography images. WSS was simulated by using a finite-element analyzer, regarding the blood as a Newtonian fluid and the vessel as a rigid wall. Analysis was carried out to compare the WSS in the portal hypertension group with that in healthy controls. For the idealized models, WSS in the portal hypertension group (0-10 dyn/cm(2)) was significantly lower than that in the healthy controls (10-20 dyn/cm(2)), and low WSS area (0-1 dyn/cm(2)) only occurred in the left wall of the PV in the portal hypertension group. Different angles of PV-SV and SMV-SV had different effects on the magnitude and distribution of WSS, and low WSS area often occurred in smaller PV-SV angle and larger SMV-SV angle. In the patient-specific models, WSS in the cirrhotic patients with portal hypertension (10.13 ± 1.34 dyn/cm(2)) was also significantly lower than that in the healthy controls (P portal hypertension, the low WSS area extended to wider levels and the magnitude of WSS reached lower levels, thereby being more prone to disturbed flow occurrence. Cirrhotic patients with portal hypertension show dramatic hemodynamic changes with lower WSS and greater potential for disturbed flow, representing a possible causative factor of PV thrombosis.

  10. Measurement and analysis of flow wall shear stress in an interior subchannel of triangular array rods. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Fakori-Monazah, M.R.; Todreas, N.E.

    1977-08-01

    A simulated model of triangular array rods with pitch to diameter ratio of 1.10 (as a test section) and air as the fluid flow was used to study the LMFBR hydraulic parameters. The wall shear stress distribution around the rod periphery, friction factors, static pressure distributions and turbulence intensity corresponding to various Reynolds numbers ranging from 4140 to 36170 in the central subchannel were measured. Various approaches for measurement of wall shear stress were compared. The measurement was performed using the Preston tube technique with the probe outside diameter equal to 0.014 in.

  11. Wall Shear Stress Distribution in a Patient-Specific Cerebral Aneurysm Model using Reduced Order Modeling

    Science.gov (United States)

    Han, Suyue; Chang, Gary Han; Schirmer, Clemens; Modarres-Sadeghi, Yahya

    2016-11-01

    We construct a reduced-order model (ROM) to study the Wall Shear Stress (WSS) distributions in image-based patient-specific aneurysms models. The magnitude of WSS has been shown to be a critical factor in growth and rupture of human aneurysms. We start the process by running a training case using Computational Fluid Dynamics (CFD) simulation with time-varying flow parameters, such that these parameters cover the range of parameters of interest. The method of snapshot Proper Orthogonal Decomposition (POD) is utilized to construct the reduced-order bases using the training CFD simulation. The resulting ROM enables us to study the flow patterns and the WSS distributions over a range of system parameters computationally very efficiently with a relatively small number of modes. This enables comprehensive analysis of the model system across a range of physiological conditions without the need to re-compute the simulation for small changes in the system parameters.

  12. Wall shear stress effects of different endodontic irrigation techniques and systems.

    Science.gov (United States)

    Goode, Narisa; Khan, Sara; Eid, Ashraf A; Niu, Li-na; Gosier, Johnny; Susin, Lisiane F; Pashley, David H; Tay, Franklin R

    2013-07-01

    This study examined débridement efficacy as a result of wall shear stresses created by different irrigant delivery/agitation techniques in an inaccessible recess of a curved root canal model. A reusable, curved canal cavity containing a simulated canal fin was milled into mirrored titanium blocks. Calcium hydroxide (Ca(OH)2) paste was used as debris and loaded into the canal fin. The titanium blocks were bolted together to provide a fluid-tight seal. Sodium hypochlorite was delivered at a previously-determined flow rate of 1 mL/min that produced either negligible or no irrigant extrusion pressure into the periapex for all the techniques examined. Nine irrigation delivery/agitation techniques were examined: NaviTip passive irrigation control, Max-i-Probe(®) side-vented needle passive irrigation, manual dynamic agitation (MDA) using non-fitting and well-fitting gutta-percha points, EndoActivator™ sonic agitation with medium and large points, VPro™ EndoSafe™ irrigation system, VPro™ StreamClean™ continuous ultrasonic irrigation and EndoVac apical negative pressure irrigation. Débridement efficacies were analysed with Kruskal-Wallis ANOVA and Dunn's multiple comparisons tests (α=0.05). EndoVac was the only technique that removed more than 99% calcium hydroxide debris from the canal fin at the predefined flow rate. This group was significantly different (psystem to significantly clean more debris from a mechanically inaccessible recess of the model curved root canal may be caused by robust bubble formation during irrigant delivery, creating higher wall shear stresses by a two-phase air-liquid flow phenomenon that is well known in other industrial débridement systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Multi wall carbon nanotubes induce oxidative stress and cytotoxicity in human embryonic kidney (HEK293) cells.

    Science.gov (United States)

    Reddy, Anreddy Rama Narsimha; Reddy, Yellu Narsimha; Krishna, Devarakonda Rama; Himabindu, Vurimindi

    2010-06-04

    The present study was aimed at evaluating the potential toxicity and the general mechanism involved in multi wall carbon nanotubes (MWCNT)-induced cytotoxicity using human embryonic kidney cell line (HEK293) cells. Two multi wall carbon nanotubes (coded as MWCNT1, size: 90-150nm and MWCNT2, size: 60-80nm) used in this study are MWCNT1 (produced by the electric arc method and size of the nanotubes was 90-150nm) and MWCNT2 (produced by the chemical vapor deposition method with size of 60-80nm). To elucidate the possible mechanisms of MWCNT induced cytotoxicity, cell viability, mitochondrial function (MTT assay), cell membrane damage (LDH assay), reduced glutathione (GSH), interleukin-8 (IL-8) and lipid peroxidation levels were quantitatively assessed under carbon nanotubes exposed (48h) conditions. Exposure of different sizes of two carbon nanotubes at dosage levels between 3 and 300mug/ml decreased cell viability in a concentration dependent manner. The IC(50) values (concentration of nanoparticles to induce 50% cell mortality) of two (MWCNT1, MWCNT2) nanoparticles were found as 42.10 and 36.95mug/ml. Exposure of MWCNT (10-100mug/ml) to HEK cells resulted in concentration dependent cell membrane damage (as indicated by the increased levels of LDH), increased production of IL-8, increased TBARS and decreased intracellular glutathione levels. The cytotoxicity and oxidative stress was significantly more in MWCNT2 exposed cells than MWCNT1. In summary, exposure of carbon nanotubes resulted in a concentration dependent cytotoxicity in cultured HEK293 cells that was associated with increased oxidative stress. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Effect of historical earthquakes on pre-stressed anchor tie back diaphragm wall and on near-by building

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2013-04-01

    Full Text Available Pre-stressed tie back anchored diaphragm walls are considered one of the safest lateral supports which help in overall stability when there is a significant difference in land level between back and front of these walls. Permanent lateral supports to these walls are frequently represented by supporting it laterally with foundation and floor slabs of the building. In this paper a special study of one raw anchor diaphragm wall subjected to different earthquake dynamic loads will be presented. The wall retains an excavation of 9.5 m and supports laterally a near-by 5 floor building. Five historical strong motions with different fundamental frequencies are subjected on the wall. The wall displacement, straining actions, anchor extreme force and the influence of variation of anchor stiffness are calculated using a dynamic Plaxis finite element program. The soil is considered as elasto-plastic material and represented using Mohr–Coulomb criteria, the wall and the anchor are considered to behave elastically. Prescribed displacement at the lower bottom boundary represents the earthquake motion. Far left and right absorbent boundaries are assumed to prevent dynamic wave reflection. Four static phases representing construction procedure and one dynamic loading phase are considered. It is found that the straining actions of different historical earthquakes match in shape with each other, the only change is in the amplitude which is affected by earthquake fundamental frequency and its intensity. The maximum dynamic lateral displacement of the wall is at its free top. The near-by building shows a differential settlement towards the wall which causes a change in the sign and amplitude of the straining actions. Increasing the stiffness of anchor was also studied and it was found that it reduces too much the maximum dynamic top wall lateral displacement.

  15. Rationale and Design of a Randomized Clinical Trial Comparing Stress Reduction Treatment to Usual Cardiac Care: The Reducing Vulnerability to ICD Shock-Treated Ventricular Arrhythmias (RISTA) Trial

    Science.gov (United States)

    Donahue, Rebecca G.; Lampert, Rachel; Dornelas, Ellen; Clemow, Lynn; Burg, Matthew M.

    2010-01-01

    Objective Present the design of a multicenter randomized trial testing the effects of Stress Reduction Treatment (SRT) on the prevalence of shock treated ventricular arrhythmias among patients with an implantable cardioverter defibrillator (ICD). Significant adjustment problems secondary to ICD shock can increase the likelihood of arrhythmias requiring shock for termination. Whether SRT can reduce arrhythmias requiring shock for termination in patients with ICDs has not been tested in clinical trials. Methods New ICD recipients and previous recipients who have received an appropriate therapeutic shock in the past 6 months (n=304) will be enrolled and randomized to either SRT or usual cardiac care. Participants complete a psychosocial questionnaire and undergo laboratory mental stress testing and 24-hour holter monitoring with diary at study entry and approximately 4 months later. Follow-ups are completed at 6-, 12-, and 24-months post randomization to assess occurrence of ICD shock for ventricular arrhythmias (primary outcome), ATP events, medication changes, hospitalizations, deaths, and quality of life. Results Log-rank test and Cox proportional hazards model will be used to test the effects of SRT on time to first shock treated ventricular arrhythmia, with exploratory analyses testing the effects on overall frequency of ventricular arrhythmia. Secondary analyses will test the effects of SRT on lab stress induced and 24-hour arrhythmogenic electrophysiological indices from pre- to post-treatment, and both quality of life and measures of anger across the 2-years of the study. Conclusions The RISTA Trial is the first large scale randomized clinical trial designed to evaluate the effect of SRT on the prevalence of shock-treated arrhythmias among patients with an ICD. Results may demonstrate a treatment that can reduce vulnerability to arrhythmia provoked shock and improve quality of life. PMID:20028832

  16. Wall shear stress fluctuations: Mixed scaling and their effects on velocity fluctuations in a turbulent boundary layer

    Science.gov (United States)

    Diaz-Daniel, Carlos; Laizet, Sylvain; Vassilicos, J. Christos

    2017-05-01

    The present work investigates numerically the statistics of the wall shear stress fluctuations in a turbulent boundary layer (TBL) and their relation to the velocity fluctuations outside of the near-wall region. The flow data are obtained from a Direct Numerical Simulation (DNS) of a zero pressure-gradient TBL using the high-order flow solver Incompact3D [S. Laizet and E. Lamballais, "High-order compact schemes for incompressible flows: A simple and efficient method with quasi-spectral accuracy," J. Comput. Phys. 228(16), 5989 (2009)]. The maximum Reynolds number of the simulation is R e𝜃≈2000 , based on the free-stream velocity and the momentum thickness of the boundary layer. The simulation data suggest that the root-mean-squared fluctuations of the streamwise and spanwise wall shear-stress components τx and τz follow a logarithmic dependence on the Reynolds number, consistent with the empirical correlation of Örlü and Schlatter [R. Örlü and P. Schlatter, "On the fluctuating wall-shear stress in zero pressure-gradient turbulent boundary layer flows," Phys. Fluids 23, 021704 (2011)]. These functional dependencies can be used to estimate the Reynolds number dependence of the wall turbulence dissipation rate in good agreement with reference DNS data. Our results suggest that the rare negative events of τx can be associated with the extreme values of τz and are related to the presence of coherent structures in the buffer layer, mainly quasi-streamwise vortices. We also develop a theoretical model, based on a generalisation of the Townsend-Perry hypothesis of wall-attached eddies, to link the statistical moments of the filtered wall shear stress fluctuations and the second order structure function of fluctuating velocities at a distance y from the wall. This model suggests that the wall shear stress fluctuations may induce a higher slope in the turbulence energy spectra of streamwise velocities than the one predicted by the Townsend-Perry attached

  17. Analysis of Cell Wall-Related Genes in Organs of Medicago sativa L. under Different Abiotic Stresses.

    Science.gov (United States)

    Behr, Marc; Legay, Sylvain; Hausman, Jean-Francois; Guerriero, Gea

    2015-07-16

    Abiotic constraints are a source of concern in agriculture, because they can have a strong impact on plant growth and development, thereby affecting crop yield. The response of plants to abiotic constraints varies depending on the type of stress, on the species and on the organs. Although many studies have addressed different aspects of the plant response to abiotic stresses, only a handful has focused on the role of the cell wall. A targeted approach has been used here to study the expression of cell wall-related genes in different organs of alfalfa plants subjected for four days to three different abiotic stress treatments, namely salt, cold and heat stress. Genes involved in different steps of cell wall formation (cellulose biosynthesis, monolignol biosynthesis and polymerization) have been analyzed in different organs of Medicago sativa L. Prior to this analysis, an in silico classification of dirigent/dirigent-like proteins and class III peroxidases has been performed in Medicago truncatula and M. sativa. The final goal of this study is to infer and compare the expression patterns of cell wall-related genes in response to different abiotic stressors in the organs of an important legume crop.

  18. Distal coronary embolization following acute myocardial infarction increases early infarct size and late left ventricular wall thinning in a porcine model.

    Science.gov (United States)

    Thomas, Reuben M; Lim, Sang Yup; Qiang, Beiping; Osherov, Azriel B; Ghugre, Nilesh R; Noyan, Hossein; Qi, Xiuling; Wolff, Rafael; Ladouceur-Wodzak, Michelle; Berk, Thomas A; Butany, Jagdish; Husain, Mansoor; Wright, Graham A; Strauss, Bradley H

    2015-12-01

    Distal coronary embolization (DCE) of thrombotic material occurs frequently during percutaneous interventions for acute myocardial infarction and can alter coronary flow grades. The significance of DCE on infarct size and myocardial function remains unsettled. The aims of this study were to evaluate the effects of DCE sufficient to cause no-reflow on infarct size, cardiac function and ventricular remodeling in a porcine acute myocardial infarction model. Female Yorkshire pigs underwent 60 min balloon occlusion of the left anterior descending coronary artery followed by reperfusion and injection of either microthrombi (prepared from autologous porcine blood) sufficient to cause no-reflow (DCE), or saline (control). Animals were sacrificed at 3 h (n = 5), 3 days (n = 20) or 6 weeks (n = 20) post-AMI. Cardiovascular magnetic resonance (CMR), serum troponin-I, and cardiac gelatinase (MMP) and survival kinase (Akt) activities were assessed. At 3d, DCE increased infarct size (CMR: 18.8% vs. 14.5%, p = 0.04; serum troponin-I: 13.3 vs. 6.9 ng/uL, p infarct size, ventricular volume or ejection fraction between the two groups, although infarct transmurality (70% vs. 57%, pinfarct size, but without affecting later infarct size, cardiac function or ventricular volumes. The significance of the later remodelling changes (ventricular thinning and transmurality) following DCE, possibly due to changes in MMP-2 activity and Akt activation, merits further study.

  19. New Method for Mitigating the Tensile Residual Stresses induced on the Inside Wall of Butt Welded Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Kim, Kang Soo; Kim, Ki Baik; Kim, Kwang Mo; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    Because dissimilar metal welding between ferritic steel and austenitic stainless steel needs not post weld heat treatment (PWHT), the effect of residual stresses induce during the welding should be investigated to assess the reliability of the weld process. It is known that the A82/182 weld metals, which are used for filler metals of the butt welding between the ferritic steel pipe and the stainless steel pipe, are susceptible to PWSCC (Primary Water Stress Corrosion Cracking) in PWR plant. The tensile residual stresses on the inside wall of the pipe, which are induced during the production welding, tend to be the dominant driving force for the PWSCC initiation and crack growth. In order to prevent the PWSCC the tensile residual stresses should be mitigated or removed. Two methods, weld overlay and mechanical stress improvement process (MSIP) have been considered proper tools to reduce the tensile residual stresses and to mitigate the PWSCC susceptibility of the dissimilar metal welded nozzles and pipes. In this research, new method for mitigating the tensile residual stresses induced on the inside wall of pipe during the production welding between the ferritic steel pipe and the stainless steel pipe was suggested. This new method may be able to apply to the SA508 /A182/SS316 nozzles of the pressure vessels in PWR to prevent PWSCC susceptibility as another substitute method.

  20. Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death.

    Science.gov (United States)

    Liu, Yong-Hua; Offler, Christina E; Ruan, Yong-Ling

    2016-09-01

    Reduced cell wall invertase (CWIN) activity has been shown to be associated with poor seed and fruit set under abiotic stress. Here, we examined whether genetically increasing native CWIN activity would sustain fruit set under long-term moderate heat stress (LMHS), an important factor limiting crop production, by using transgenic tomato (Solanum lycopersicum) with its CWIN inhibitor gene silenced and focusing on ovaries and fruits at 2 d before and after pollination, respectively. We found that the increase of CWIN activity suppressed LMHS-induced programmed cell death in fruits. Surprisingly, measurement of the contents of H2O2 and malondialdehyde and the activities of a cohort of antioxidant enzymes revealed that the CWIN-mediated inhibition on programmed cell death is exerted in a reactive oxygen species-independent manner. Elevation of CWIN activity sustained Suc import into fruits and increased activities of hexokinase and fructokinase in the ovaries in response to LMHS Compared to the wild type, the CWIN-elevated transgenic plants exhibited higher transcript levels of heat shock protein genes Hsp90 and Hsp100 in ovaries and HspII17.6 in fruits under LMHS, which corresponded to a lower transcript level of a negative auxin responsive factor IAA9 but a higher expression of the auxin biosynthesis gene ToFZY6 in fruits at 2 d after pollination. Collectively, the data indicate that CWIN enhances fruit set under LMHS through suppression of programmed cell death in a reactive oxygen species-independent manner that could involve enhanced Suc import and catabolism, HSP expression, and auxin response and biosynthesis. © 2016 American Society of Plant Biologists. All rights reserved.

  1. Intramural Ventricular Septal Defect Is a Distinct Clinical Entity Associated With Postoperative Morbidity in Children After Repair of Conotruncal Anomalies

    National Research Council Canada - National Science Library

    Patel, Jyoti K; Glatz, Andrew C; Ghosh, Reena M; Jones, Shannon M; Natarajan, Shobha; Ravishankar, Chitra; Mascio, Christopher E; Spray, Thomas L; Cohen, Meryl S

    2015-01-01

    BACKGROUND—Intramural ventricular septal defects (VSDs) are interventricular communications through right ventricular free wall trabeculations that can occur after repair of conotruncal anomalies...

  2. Manufacture of high aspect ratio micro-pillar wall shear stress sensor arrays

    Science.gov (United States)

    Gnanamanickam, Ebenezer P.; Sullivan, John P.

    2012-12-01

    In the field of experimental fluid mechanics the measurement of unsteady, distributed wall shear stress has proved historically challenging. Recently, sensors based on an array of flexible micro-pillars have shown promise in carrying out such measurements. Similar sensors find use in other applications such as cellular mechanics. This work presents a manufacturing technique that can manufacture micro-pillar arrays of high aspect ratio. An electric discharge machine (EDM) is used to manufacture a micro-drilling tool. This micro-drilling tool is used to form holes in a wax sheet which acts as the mold for the micro-pillar array. Silicone rubber is cast in these molds to yield a micro-pillar array. Using this technique, micro-pillar arrays with a maximum aspect ratio of about 10 have been manufactured. Manufacturing issues encountered, steps to alleviate them and the potential of the process to manufacture similar micro-pillar arrays in a time-efficient manner are also discussed.

  3. High wall shear stress and high-risk plaque: an emerging concept.

    Science.gov (United States)

    Eshtehardi, Parham; Brown, Adam J; Bhargava, Ankit; Costopoulos, Charis; Hung, Olivia Y; Corban, Michel T; Hosseini, Hossein; Gogas, Bill D; Giddens, Don P; Samady, Habib

    2017-07-01

    In recent years, there has been a significant effort to identify high-risk plaques in vivo prior to acute events. While number of imaging modalities have been developed to identify morphologic characteristics of high-risk plaques, prospective natural-history observational studies suggest that vulnerability is not solely dependent on plaque morphology and likely involves additional contributing mechanisms. High wall shear stress (WSS) has recently been proposed as one possible causative factor, promoting the development of high-risk plaques. High WSS has been shown to induce specific changes in endothelial cell behavior, exacerbating inflammation and stimulating progression of the atherosclerotic lipid core. In line with experimental and autopsy studies, several human studies have shown associations between high WSS and known morphological features of high-risk plaques. However, despite increasing evidence, there is still no longitudinal data linking high WSS to clinical events. As the interplay between atherosclerotic plaque, artery, and WSS is highly dynamic, large natural history studies of atherosclerosis that include WSS measurements are now warranted. This review will summarize the available clinical evidence on high WSS as a possible etiological mechanism underlying high-risk plaque development.

  4. The overloaded right heart and ventricular interdependence.

    Science.gov (United States)

    Naeije, Robert; Badagliacca, Roberto

    2017-10-01

    The right and the left ventricle are interdependent as both structures are nested within the pericardium, have the septum in common and are encircled with common myocardial fibres. Therefore, right ventricular volume or pressure overloading affects left ventricular function, and this in turn may affect the right ventricle. In normal subjects at rest, right ventricular function has negligible interaction with left ventricular function. However, the right ventricle contributes significantly to the normal cardiac output response to exercise. In patients with right ventricular volume overload without pulmonary hypertension, left ventricular diastolic compliance is decreased and ejection fraction depressed but without intrinsic alteration in contractility. In patients with right ventricular pressure overload, left ventricular compliance is decreased with initial preservation of left ventricular ejection fraction, but with eventual left ventricular atrophic remodelling and altered systolic function. Breathing affects ventricular interdependence, in healthy subjects during exercise and in patients with lung diseases and altered respiratory system mechanics. Inspiration increases right ventricular volumes and decreases left ventricular volumes. Expiration decreases both right and left ventricular volumes. The presence of an intact pericardium enhances ventricular diastolic interdependence but has negligible effect on ventricular systolic interdependence. On the other hand, systolic interdependence is enhanced by a stiff right ventricular free wall, and decreased by a stiff septum. Recent imaging studies have shown that both diastolic and systolic ventricular interactions are negatively affected by right ventricular regional inhomogeneity and prolongation of contraction, which occur along with an increase in pulmonary artery pressure. The clinical relevance of these observations is being explored. Published on behalf of the European Society of Cardiology. All rights

  5. ST segment/heart rate hysteresis improves the diagnostic accuracy of ECG stress test for coronary artery disease in patients with left ventricular hypertrophy.

    Science.gov (United States)

    Zimarino, Marco; Montebello, Elena; Radico, Francesco; Gallina, Sabina; Perfetti, Matteo; Iachini Bellisarii, Francesco; Severi, Silva; Limbruno, Ugo; Emdin, Michele; De Caterina, Raffaele

    2016-10-01

    The exercise electrocardiographic stress test (ExET) is the most widely used non-invasive diagnostic method to detect coronary artery disease. However, the sole ST depression criteria (ST-max) have poor specificity for coronary artery disease in patients with left ventricular hypertrophy. We hypothesised that ST-segment depression/heart rate hysteresis, depicting the relative behaviour of ST segment depression during the exercise and recovery phase of the test might increase the diagnostic accuracy of ExET for coronary artery disease detection in such patients. In three cardiology centres, we studied 113 consecutive patients (mean age 66 ± 2 years; 88% men) with hypertension-related left ventricular hypertrophy at echocardiography, referred to coronary angiography after an ExET. The following ExET criteria were analysed: ST-max, chronotropic index, heart rate recovery, Duke treadmill score, ST-segment depression/heart rate hysteresis. We detected significant coronary artery disease at coronary angiography in 61 patients (53%). At receiver-operating characteristic analysis, ST-segment depression/heart rate hysteresis had the highest area under the curve value (0.75, P coronary artery disease than conventional criteria in patients with hypertension-related left ventricular hypertrophy. © The European Society of Cardiology 2016.

  6. Outcomes of posterior wall fractures of the acetabulum treated nonoperatively after diagnostic screening with dynamic stress examination under anesthesia.

    Science.gov (United States)

    Grimshaw, Charles S; Moed, Berton R

    2010-12-01

    Dynamic stress fluoroscopy with the patient under general anesthesia has been advocated as a clinical measure of hip stability and congruity in patients with a posterior wall acetabular fracture. The purpose of this study was to establish the predictive value of the dynamic stress fluoroscopic examination for these fractures by evaluating clinical and radiographic outcomes after nonoperative treatment of fractures found to be stable with this examination. Twenty-one consecutive patients with an acute posterior wall fracture of the acetabulum who were shown to have a stable hip joint by dynamic stress fluoroscopy while they were under general anesthesia were treated nonoperatively. At the time of follow-up, the patients underwent clinical and/or radiographic evaluation. Clinical follow-up was performed for eighteen patients at a minimum of two years after injury, at which time the average modified Merle d'Aubigné score was very good, with no one having less than a good clinical outcome. Fifteen of these eighteen patients had radiographic evaluation at a minimum of two years, and all were found to have a congruent joint with a normal joint space and no evidence of posttraumatic arthritis. Hip joint stability determined with dynamic stress fluoroscopy with the patient under general anesthesia after a posterior wall acetabular fracture is predictive of hip joint congruity, an excellent radiographic outcome, and a good-to-excellent early clinical outcome after nonoperative treatment.

  7. Non-β-blocking R-carvedilol enantiomer suppresses Ca2+ waves and stress-induced ventricular tachyarrhythmia without lowering heart rate or blood pressure

    OpenAIRE

    Zhang, Jingqun; Zhou, Qiang; Smith, Chris D.; Chen, Haiyan; Tan, Zhen; Chen, Biyi; Nani, Alma; Wu, Guogen; Song, Long-Sheng; Fill, Michael; Back, Thomas G.; Wayne Chen, S.R.

    2015-01-01

    Carvedilol is the current β-blocker of choice for suppressing ventricular tachyarrhythmia (VT). However, carvedilol’s benefits are dose-limited, attributable to its potent β-blocking activity that can lead to bradycardia and hypotension. The clinically used carvedilol is a racemic mixture of β-blocking S-carvedilol and non-β-blocking R-carvedilol. We recently reported that novel non-β-blocking carvedilol analogues are effective in suppressing arrhythmogenic Ca2+ waves and stress-induced VT wi...

  8. Heat stress causes alterations in the cell-wall polymers and anatomy of coffee leaves (Coffea arabica L.).

    Science.gov (United States)

    Lima, Rogério Barbosa; dos Santos, Tiago Benedito; Vieira, Luiz Gonzaga Esteves; Ferrarese, Maria de Lourdes Lúcio; Ferrarese-Filho, Osvaldo; Donatti, Lucélia; Boeger, Maria Regina Torres; Petkowicz, Carmen Lúcia de Oliveira

    2013-03-01

    Coffee plants were subjected to heat stress (37 °C) and compared with control plants (24 °C). Cell wall polysaccharides were extracted using water (W), EDTA (E) and 4M NaOH (H30 and H70). In addition, monolignols were analyzed, and the leaves were observed by microscopy. Plants under heat stress accumulated higher contents of arabinose and galactose in fraction W. Xylose contents were observed to decrease in H30 fractions after the heat stress, whereas galactose and uronic acid increased. H70 fractions from plants exposed to heat stress showed increased xylose contents, whereas the contents of arabinose and glucose decreased. Differences in the molar-mass profiles of polysaccharides were also observed. The primary monolignol contents increased after the heat stress. Structural alterations in palisade cells and ultrastructural damage in chloroplasts were also observed. Our results demonstrate that the chemical profile of coffee cell-wall polymers and structural cell anatomy change under heat stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

    Science.gov (United States)

    Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming

    2014-01-01

    Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.

  10. Comparative assessment of rest and post-stress left ventricular volumes and left ventricular ejection fraction on gated myocardial perfusion imaging (MPI) and echocardiography in patients with transient ischaemic dilation on adenosine MPI: myocardial stunning or subendocardial hypoperfusion?

    Science.gov (United States)

    Emmett, Louise; Ng, Austin; Ha, Leo; Russo, Robert; Mansberg, Robert; Zhao, Wei; Chow, S Vincent; Kritharides, Leonard

    2012-08-01

    Transient ischaemic dilation (TID) on myocardial perfusion imaging (MPI) is an important finding, conveying a high risk of subsequent cardiac events. However, the mechanism leading to TID on MPI is not well elucidated. This study aimed to determine if TID is due to true LV cavity dilation and ventricular stunning, or is due to relative subendocardial hypoperfusion. 31 patients undergoing single-day Tc-99m adenosine sestamibi MPI were recruited. All had routine ECG-gated single-day rest-stress adenosine MPI, with transthoracic echocardiograms (echo) acquired concurrently at rest, and both immediately, and 2 hours, post-stress. Echocardiography was performed using a Vivid-7 (GE). LV volumes and LVEF were quantified blinded to MPI results, using biplane Simpson method on echo, and quantitatively (including TID) with QGS(®), on MPI. Patients were divided into quartiles for TID, with the top quartile considered TID positive [TID+ 9/31 (TID ratio 1.3 ± 0.09)], and TID negative [TID- 22/31 (TID ratio 1.01 ± 0.04)]. There was good correlation between resting echo and MPI physical measurements (LVEDV r(2) = 0.79, LVESV r(2) = 0.9, and LVEF r(2) = 0.75). On MPI, a significant drop in LVEF was observed between rest and early stress in the TID+ group (56.6% vs 46.5%, P subendocardial hypoperfusion and impaired coronary flow reserve.

  11. Postnatal myocardium remodelling generates inhomogeneity in the architecture of the ventricular mass.

    Science.gov (United States)

    Jouk, Pierre-Simon; Truong, Ba Luu; Michalowicz, Gabrielle; Usson, Yves

    2017-11-28

    The 3D architecture of the ventricular mass is poorly known, although in vivo imaging techniques show the physiological inhomogeneity of ventricular walls mechanics. Polarized light imaging makes it possible to quantitatively analyse the myosin filament orientation. In this paper, we focus on the study the 3D architecture and regional isotropy of myocardial cells. Twenty normal human hearts, 10 from the perinatal period and 10 from the post-neonatal period were studied by polarized light microscopy. In each voxel of the ventricular mass (90 × 90 × 500 µm) the principal orientation segment was automatically and unambiguously extracted as well as a regional isotropy index (regional orientation tensor of the voxel neighbourhood). During the first months of postnatal age, the median regional isotropy values decreased in the ventricular mesh. This global decrease was not homogeneous across the ventricular walls. From the perinatal to the neonatal period, this decrease was more marked in the inner two-third of the lateral left ventricular wall and in the right part of the interventricular septum. There was a progressive post-neonatal appearance of a particularly inhomogeneous secondary arrangement of myocardial cells with alternation of thick low-RI and thin high-RI areas. This study has shown a postnatal change in ventricular myocardial architecture, which became more inhomogeneous. The cell rearrangements responsible for the inhomogeneity in ventricular myocardial architecture are revealed by a variation of the regional isotropy index. These major changes are probably an adaptive consequence of the major haemodynamic changes occurring after birth during the neonatal period that generates major parietal stress variations and parietal remodelling.

  12. In vitro blood flow model with physiological wall shear stress for hemocompatibility testing-An example of coronary stent testing.

    Science.gov (United States)

    Engels, Gerwin Erik; Blok, Sjoerd Leendert Johannes; van Oeveren, Willem

    2016-09-18

    Hemocompatibility of blood contacting medical devices has to be evaluated before their intended application. To assess hemocompatibility, blood flow models are often used and can either consist of in vivo animal models or in vitro blood flow models. Given the disadvantages of animal models, in vitro blood flow models are an attractive alternative. The in vitro blood flow models available nowadays mostly focus on generating continuous flow instead of generating a pulsatile flow with certain wall shear stress, which has shown to be more relevant in maintaining hemostasis. To address this issue, the authors introduce a blood flow model that is able to generate a pulsatile flow and wall shear stress resembling the physiological situation, which the authors have coined the "Haemobile." The authors have validated the model by performing Doppler flow measurements to calculate velocity profiles and (wall) shear stress profiles. As an example, the authors evaluated the thrombogenicity of two drug eluting stents, one that was already on the market and one that was still under development. After identifying proper conditions resembling the wall shear stress in coronary arteries, the authors compared the stents with each other and often used reference materials. These experiments resulted in high contrast between hemocompatible and incompatible materials, showing the exceptional testing capabilities of the Haemobile. In conclusion, the authors have developed an in vitro blood flow model which is capable of mimicking physiological conditions of blood flow as close as possible. The model is convenient in use and is able to clearly discriminate between hemocompatible and incompatible materials, making it suitable for evaluating the hemocompatible properties of medical devices.

  13. 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.

  14. Assessment of perfusion and wall-motion abnormalities and transient ischemic dilation in regadenoson stress cardiac magnetic resonance perfusion imaging.

    Science.gov (United States)

    Hojjati, Mohammad R; Muthupillai, Raja; Wilson, James M; Preventza, Ourania A; Cheong, Benjamin Y C

    2014-06-01

    Vasodilator first-pass stress cardiac magnetic resonance perfusion imaging [stress cardiac magnetic resonance (CMR)] is a reliable, noninvasive method for evaluating myocardial ischemia; however, it does not routinely evaluate metrics such as wall-motion abnormality (WMA) and transient ischemic dilation (TID). Using the new selective A2A adenosine receptor agonist regadenoson, we tested a novel protocol for assessing perfusion defects, WMA, and TID in a single stress CMR session. We evaluated 29 consecutive patients who presented for clinically indicated regadenoson stress CMR. Immediately before and after the regadenoson stress perfusion sequence, we obtained baseline and post-stress cine images in the short-axis orientation to detect worsening or newly developed WMAs. This approach also allowed evaluation of TID. Delayed-enhancement imaging was performed in the standard orientations. All patients tolerated the procedure well. Thirteen patients (45 %) had perfusion abnormalities, and four patients developed TID. Seven patients had WMAs, and three of them also had TID. Patients with TID ± WMAs had multivessel disease documented by coronary angiography. By using regadenoson to assess myocardial ischemia during stress CMR, perfusion defects, WMAs, and TID can be evaluated in a single imaging session. To our knowledge, we are the first to describe this novel approach in a vasodilator stress CMR study.

  15. Impact of flow rates in a cardiac cycle on correlations between advanced human carotid plaque progression and mechanical flow shear stress and plaque wall stress

    Directory of Open Access Journals (Sweden)

    Ferguson Marina

    2011-07-01

    Full Text Available Abstract Background Mechanical stresses are known to play important roles in atherosclerotic plaque initiation, progression and rupture. It has been well-accepted that atherosclerosis initiation and early progression correlate negatively with flow wall shear stresses (FSS. However, mechanisms governing advanced plaque progression are not well understood. Method In vivo serial MRI data (patient follow-up were acquired from 14 patients after informed consent. Each patient had 2-4 scans (scan interval: 18 months. Thirty-two scan pairs (baseline and follow-up scans were formed with slices matched for model construction and analysis. Each scan pair had 4-10 matched slices which gave 400-1000 data points for analysis (100 points per slice on lumen. Point-wise plaque progression was defined as the wall thickness increase (WTI at each data point. 3D computational models with fluid-structure interactions were constructed based on in vivo serial MRI data to extract flow shear stress and plaque wall stress (PWS on all data points to quantify correlations between plaque progression and mechanical stresses (FSS and PWS. FSS and PWS data corresponding to both maximum and minimum flow rates in a cardiac cycle were used to investigate the impact of flow rates on those correlations. Results Using follow-up scans and maximum flow rates, 19 out of 32 scan pairs showed a significant positive correlation between WTI and FSS (positive/negative/no significance correlation ratio = 19/9/4, and 26 out of 32 scan pairs showed a significant negative correlation between WTI and PWS (correlation ratio = 2/26/4. Corresponding to minimum flow rates, the correlation ratio for WTI vs. FSS and WTI vs. PWS were (20/7/5 and (2/26/4, respectively. Using baseline scans, the correlation ratios for WTI vs. FSS were (10/12/10 and (9/13/10 for maximum and minimum flow rates, respectively. The correlation ratios for WTI vs. PWS were the same (18/5/9, corresponding to maximum and minimum

  16. Impact of flow rates in a cardiac cycle on correlations between advanced human carotid plaque progression and mechanical flow shear stress and plaque wall stress.

    Science.gov (United States)

    Yang, Chun; Canton, Gador; Yuan, Chun; Ferguson, Marina; Hatsukami, Thomas S; Tang, Dalin

    2011-07-19

    Mechanical stresses are known to play important roles in atherosclerotic plaque initiation, progression and rupture. It has been well-accepted that atherosclerosis initiation and early progression correlate negatively with flow wall shear stresses (FSS). However, mechanisms governing advanced plaque progression are not well understood. In vivo serial MRI data (patient follow-up) were acquired from 14 patients after informed consent. Each patient had 2-4 scans (scan interval: 18 months). Thirty-two scan pairs (baseline and follow-up scans) were formed with slices matched for model construction and analysis. Each scan pair had 4-10 matched slices which gave 400-1000 data points for analysis (100 points per slice on lumen). Point-wise plaque progression was defined as the wall thickness increase (WTI) at each data point. 3D computational models with fluid-structure interactions were constructed based on in vivo serial MRI data to extract flow shear stress and plaque wall stress (PWS) on all data points to quantify correlations between plaque progression and mechanical stresses (FSS and PWS). FSS and PWS data corresponding to both maximum and minimum flow rates in a cardiac cycle were used to investigate the impact of flow rates on those correlations. Using follow-up scans and maximum flow rates, 19 out of 32 scan pairs showed a significant positive correlation between WTI and FSS (positive/negative/no significance correlation ratio = 19/9/4), and 26 out of 32 scan pairs showed a significant negative correlation between WTI and PWS (correlation ratio = 2/26/4). Corresponding to minimum flow rates, the correlation ratio for WTI vs. FSS and WTI vs. PWS were (20/7/5) and (2/26/4), respectively. Using baseline scans, the correlation ratios for WTI vs. FSS were (10/12/10) and (9/13/10) for maximum and minimum flow rates, respectively. The correlation ratios for WTI vs. PWS were the same (18/5/9), corresponding to maximum and minimum flow rates. Flow shear stress

  17. Ultrasonic Measurement of Transient Change in Stress-Strain Property of Radial Arterial Wall Caused by Endothelium-Dependent Vasodilation

    Science.gov (United States)

    Ikeshita, Kazuki; Hasegawa, Hideyuki; Kanai, Hiroshi

    2008-05-01

    The endothelial dysfunction is considered to be an initial step of atherosclerosis. Additionally, it was reported that the smooth muscle, which constructs the media of the artery, changes its characteristics owing to atherosclerosis. Therefore, it is essential to develop a method for assessing the regional endothelial function and mechanical property of the arterial wall. There is a conventional technique of measuring the transient change in the diameter of the brachial artery caused by flow-mediated dilation (FMD) after the release of avascularization. For more sensitive and regional evaluation, we developed a method of measuring the change in the elasticity of the radial artery due to FMD. In this study, the transient change in the mechanical property of the arterial wall was further revealed by measuring the stress-strain relationship during each heartbeat. The minute change in the thickness (strain) of the radial arterial wall during a cardiac cycle was measured by the phased tracking method, together with the waveform of blood pressure which was continuously measured with a sphygmometer at the radial artery. The transient change in stress-strain relationship during a cardiac cycle was obtained from the measured changes in wall thickness and blood pressure to show the transient change in instantaneous viscoelasticity. From the in vivo experimental results, the stress-strain relationship shows the hysteresis loop. The slope of the loop decreased owing to FMD, which shows that the elastic modulus decreased, and the increasing area of the loop depends on the ratio of the loss modulus (depends on viscosity) to the elastic modulus when the Voigt model is assumed. These results show a potential of the proposed method for the thorough analysis of the transient change in viscoelasticity due to FMD.

  18. Free convection in parallelogram-shaped enclosures with isothermal active walls: viscous shear stress in active systems

    Energy Technology Data Exchange (ETDEWEB)

    Baieri, A; Zarco-Pernia, E; Laraqi, N [Laboratoire de Thermique Interfaces Environnement, LTIE-GTE EA 4415, Universite Paris Ouest, 50 Rue de Sevres, F-92410 Ville d' Avray (France); Garcia de Maria, J-M, E-mail: abairi@u-paris10.fr, E-mail: e.zarcopernia@yahoo.fr, E-mail: nlaraqi@u-paris10.fr, E-mail: juanmario.garcia@upm.es [Departamento de Fisica Aplicada, Universidad Politecnica de Madrid, Ronda de Valencia 3, E-28012 Madrid (Spain)

    2012-10-01

    Thermocouples are often used for thermoregulation of active thermal systems. When the junctions of these sensors are under a natural convection flow, it is necessary to take into account the viscous stress that can affect the measurement of temperature and therefore the regulation set points. The main objective of this work is to study the viscous shear stress taking place close to the active hot wall in closed air-filled cavities of parallelogrammic shape. The influence of shear stress is examined for different inclination angles of the cavity and large Rayleigh numbers which are usual in thermal applications. The local stress distributions are presented for the steady state for all the geometric configurations considered. The Nusselt number at the hot wall as well as the temperature and stream function distributions in the cavities are also included. The findings obtained from the numerical simulation using the finite volume method are validated by thermal measurements on an experimental cavity. This study confirms the need to properly choose the location of thermocouples in the reference cell used for controlling the active system. (paper)

  19. Effect of stress testing on left ventricular mechanical synchrony by phase analysis of gated positron emission tomography in patients with normal myocardial perfusion

    Energy Technology Data Exchange (ETDEWEB)

    AlJaroudi, Wael [Heart and Vascular Imaging Institutes, Cleveland Clinic, Cleveland, OH (United States); Sydell and Arnold Miller Family, Heart and Vascular Institute, Robert and Suzanne Tomsich, Department of Cardiovascular Medicine, Cleveland, OH (United States); Alraies, M.C.; Di Filippo, Frank; Brunken, Richard C.; Cerqueira, Manuel D.; Jaber, Wael A. [Heart and Vascular Imaging Institutes, Cleveland Clinic, Cleveland, OH (United States)

    2012-04-15

    There are limited data on whether differences exist in left ventricular (LV) mechanical dyssynchrony indices derived from stress versus rest gated positron emission tomography (PET) in patients with normal myocardial perfusion imaging (MPI). Stress/rest {sup 82}Rb gated PET was performed in consecutive patients with normal MPI between 2006 and 2010. Patients were divided into two groups: group 1 [LV ejection fraction (EF) {>=} 55% and QRS < 120 ms] and group 2 (LVEF {<=}35%). Images were acquired on a dedicated PET scanner prior to and on a hybrid PET/CT system after November 2008. LV dyssynchrony indices [phase standard deviation (SD) and SD (ms)] were derived from stress and rest gated images. There were 91 patients in group 1 (age 61 {+-} 13, LVEF 66 {+-} 8%, normal QRS) and 126 in group 2 (age 66 {+-} 12, LVEF 25 {+-} 7%). The stress derived LVEF were significantly higher than rest for either group (p < 0.0001). Patients with cardiomyopathy had significantly higher dyssynchrony indices compared to those with normal LVEF (rest SD 49.2 {+-} 21.5 vs 16.8 {+-} 7.8 and stress SD 42.5 {+-} 19.4 vs 12.4 {+-} 3.7 , respectively, p < 0.0001 for both). The dyssynchrony indices derived from rest gated images were significantly higher than those derived from stress in both groups (p < 0.001 by unpaired and paired t test) and irrespective of the type of PET scanner utilized. Finally, 20/87 (23%) patients with normal LVEF and 27/66 (41%) of those with cardiomyopathy but without dyssynchrony based on stress indices were recategorized as having significant dyssynchrony given their resting indices. LV mechanical dyssynchrony indices by phase analysis are smaller when derived from peak stress versus rest gated PET imaging in patients with normal MPI, irrespective of the resting LVEF. (orig.)

  20. Estimation of aneurysm wall stresses created by treatment with a shape memory polymer foam device

    OpenAIRE

    Hwang, Wonjun; Volk, Brent L.; Akberali, Farida; Singhal, Pooja; Criscione, John C.; Maitland, Duncan J.

    2011-01-01

    In this study, compliant latex thin-walled aneurysm models are fabricated to investigate the effects of expansion of shape memory polymer foam. A simplified cylindrical model is selected for the in-vitro aneurysm, which is a simplification of a real, saccular aneurysm. The studies are performed by crimping shape memory polymer foams, originally 6 and 8 mm in diameter, and monitoring the resulting deformation when deployed into 4-mm-diameter thin-walled latex tubes. The deformations of the lat...

  1. Shear stress alterations in the celiac trunk of patients with a continuous-flow left ventricular assist device as shown by in-silico and in-vitro flow analyses.

    Science.gov (United States)

    Scardulla, Francesco; Pasta, Salvatore; D'Acquisto, Leonardo; Sciacca, Sergio; Agnese, Valentina; Vergara, Christian; Quarteroni, Alfio; Clemenza, Francesco; Bellavia, Diego; Pilato, Michele

    2017-08-01

    The use of left ventricular assist devices (LVADs) to treat advanced cardiac heart failure is constantly increasing, although this device leads to high risk for gastrointestinal bleeding. Using in-silico flow analysis, we quantified hemodynamic alterations due to continuous-flow LVAD (HeartWare, Inc., Framingham, MA) in the celiac trunk and major branches of the abdominal aorta, and then explored the relationship between wall shear stress (WSS) and celiac trunk orientation. To assess outflow from the aortic branch, a 3-dimensional-printed patient-specific model of the celiac trunk reconstructed from an LVAD-supported patient was used to estimate echocardiographic outflow velocities under continuous-flow conditions, and then to calibrate computational simulations. Moreover, flow pattern and resulting WSS values were computed for 5 patients with LVAD implantation. Peak WSS values were estimated on the 3 branches of the celiac trunk and the LVAD cannula. The mean WSSs demonstrated that the left gastric artery underwent the highest WSS of 9.08 ± 5.45 Pa, with an average flow velocity of 0.57 ± 0.25 m/s compared with that of other vessel districts. The common hepatic artery had a less critical WSS of 4.58 ± 1.77 Pa. A positive correlation was found between the celiac trunk angulation and the WSS stress just distal to the ostium of the celiac trunk (R = 0.9), which may increase vulnerability of this vessel to bleeding. Although further studies are needed to confirm these findings in a larger patient cohort, computational flow simulations may enhance the information of clinical image data and may have an application in clinical investigations of hemodynamic changes in LVAD-supported patients. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  2. Bi-ventricular finite element model of right ventricle overload in the healthy rat heart.

    Science.gov (United States)

    Masithulela, Fulufhelo

    2016-11-25

    The recognition of RV overpressure is critical to human life, as this may signify morbidity and mortality. Right ventricle (RV) dysfunction is understood to have an impact on the performance of the left ventricle (LV), but the mechanisms remain poorly understood. It is understood that ventricular compliance has the ability to affect cardiac performance. In this study, a bi-ventricular model of the rat heart was used in preference to other, single-ventricle models. Finite element analysis (FEA) of the bi-ventricular model provides important information on the function of the healthy heart. The passive myocardium was modelled as a nearly incompressible, hyperelastic, transversely isotropic material using finite element (FE) methods. Bi-ventricular geometries of healthy rat hearts reconstructed from magnetic resonance images were imported in Abaqus©. In simulating the normal passive filling of the rat heart, pressures of 4.8 kPa and 0.0098 kPa were applied to the inner walls of the LV and RV respectively. In addition, to simulate the overpressure of the RV, pressures of 2.4 kPa and 4.8 kPa were applied to the endocardial walls of the LV and RV respectively. As boundary conditions, the circumferential and longitudinal displacements at the base were set to zero. The radial displacements at the base were left free. The results show that the average circumferential stress at the mid-wall in the overloaded model increased from 2.8 kPa to 18.2 kPa. The average longitudinal stress increased from 1.5 kPa to 9.7 kPa. Additionally, in the radial direction, the average stress increased from 0.1 kPa to 0.6 kPa in the mid-wall. The average circumferential strain was found to be 0.138 and 0.100 on the endocardium of the over pressured and healthy model respectively. The average circumferential stress at the epicardium, mid-wall and endocardium in the case of a normal heart is 10 times lower than in the overloaded heart model. The finite analysis method is able to provide

  3. Right Ventricular Outflow Tract Tachycardia with Structural Abnormalities of the Right Ventricle and Left Ventricular Diverticulum

    Directory of Open Access Journals (Sweden)

    Bortolo Martini

    2015-01-01

    Full Text Available A 43-year-old woman presented to the emergency room with a sustained ventricular tachycardia (VT. ECG showed a QRS in left bundle branch block morphology with inferior axis. Echocardiography, ventricular angiography, and cardiac magnetic resonance imaging (CMRI revealed a normal right ventricle and a left ventricular diverticulum. Electrophysiology studies with epicardial voltage mapping identified a large fibrotic area in the inferolateral layer of the right ventricular wall and a small area of fibrotic tissue at the anterior right ventricular outflow tract. VT ablation was successfully performed with combined epicardial and endocardial approaches.

  4. New evidence for favourable effects on haemodynamics and ventricular performance after Parachute(®) implantation in humans.

    Science.gov (United States)

    Schmidt, Tobias; Frerker, Christian; Thielsen, Thomas; Dotz, Inge; Wohlmuth, Peter; Kuck, Karl-Heinz; Schäfer, Ulrich

    2014-10-01

    The Parachute(®) Ventricular Partitioning Device offers an additional strategy for heart failure patients with exclusion of the infarcted wall to decrease left ventricular volumes, myocardial work, and wall stress. The aim of the present study was to evaluate if Parachute implantation might influence acute haemodynamic and functional performance in patients with left ventricular aneurysm after anteroapical infarction. Sixteen patients underwent a Parachute device implantation. Invasive right and left heart haemodynamic assessments as well as left ventricular analysis for evaluating left ventricle end-diastolic and end-systolic volumes, and regional ventricular function were analysed. After implantation a significant increase in stroke volume (+25.4%, P = 0.0005), stroke volume index (+26.5%, P = 0.0005), cardiac output (+25.8%, P < 0.0001) and cardiac index (+25.9%, P < 0.0001) was found. In addition to an increase in mean aortic (P = 0.0050) and pulmonary pressure (P = 0.0347), there were significant increases in stroke work index (P = 0.0003), left (P = 0.0015) and right (P = 0.0024) ventricular stroke work index as well as left and right cardiac work index (both P = 0.0001), while the remaining haemodynamic parameters remained unchanged. Left ventricular analysis showed an acute reduction of the left ventricular end-diastolic volume (-18.0%, P < 0.0001) and left ventricular end-systolic volume (-26.3%, P < 0.0001) and an increase in ejection fraction from 22.9 to 30.6% (+38.4%, P < 0.0001). Most interestingly, the basal wall segments displayed an increased contribution to the left ventricular ejection fraction with increased wall motion in nearly all segments (except the apex region). The data demonstrate the acute haemodynamic efficacy of Parachute device implantation. The implantation of the device displays immediate significant left ventricular volume reduction leading to an acute improved right and left

  5. The relationship between ischemia-induced left ventricular dysfunction, coronary flow reserve, and coronary steal on regadenoson stress-gated 82Rb PET myocardial perfusion imaging

    Science.gov (United States)

    Van Tosh, Andrew; Votaw, John R.; Reichek, Nathaniel; Palestro, Christopher J.; Nichols, Kenneth J.

    2014-01-01

    Background Gated rubidium-82 (82Rb) positron emission tomography (PET) imaging studies are acquired both at rest and during pharmacologic stress. Stress-induced ischemic left ventricular dysfunction (LVD) can produce a significant decrease in left ventricular ejection fraction (LVEF) from rest to stress. We determined the prevalence on PET of stress LVD with reduced ejection fraction (EF) and its association with absolute global and regional coronary flow reserve (CFR), and with relative perfusion defect summed difference score (SDS). Methods and Results We studied 205 patients with known or suspected coronary disease (120 M, 75 F, age 69 ± 13 years) who had clinically indicated rest/regadenoson stress 82Rb PET/CT studies. Data were acquired in dynamic gated list mode. Global and 17-segment regional CFR values were computed from first-pass flow data using a 2-compartment model and factor analysis applied to auto-generated time-activity curves. Rest and stress LVEF and SDS were quantified from gated equilibrium myocardial perfusion tomograms using Emory Cardiac Toolbox software. LVD was defined as a change in LVEF of ≤−5% from rest to stress. A subgroup of 109 patients also had coronary angiography. Stress LVD developed in 32 patients (16%), with mean EF change of −10 ± 5%, vs +6 ± 7% for patients without LVD (P < .0001). EF was similar at rest in patients with and without stress LVD (57 ± 18% vs 56 ± 16%, P = .63), but lower during stress for patients with LVD (47 ± 20% vs 61 ± 16%, P = .0001). CFR was significantly lower in patients with LVD (1.61 ± 0.67 vs 2.21 ± 1.03, Wilcoxon P = .002), and correlated significantly with change in EF (r = 0.35, P < .0001), but not with SDS (r = −0.13, P = .07). The single variable most strongly associated with high risk of CAD (i.e., left main stenosis ≥50%, LAD % stenosis ≥70%, and/or 3-vessel disease) was stress EF (χ2 = 17.3, P < .0001). There was a higher prevalence of patients with territorial CFR

  6. Penetrative Internal Oxidation from Alloy 690 Surfaces and Stress Corrosion Crack Walls during Exposure to PWR Primary Water

    Science.gov (United States)

    Olszta, Matthew J.; Schreiber, Daniel K.; Thomas, Larry E.; Bruemmer, Stephen M.

    Analytical electron microscopy and three-dimensional atom probe tomography (ATP) examinations of surface and near-surface oxidation have been performed on Ni-30%Cr alloy 690 materials after exposure to high-temperature, simulated PWR primary water. The oxidation nanostructures have been characterized at crack walls after stress-corrosion crack growth tests and at polished surfaces of unstressed specimens for the same alloys. Localized oxidation was discovered for both crack walls and surfaces as continuous filaments (typically dislocations were oxidized in non-deformed materials, while the oxidation path appeared to be along more complex dislocation substructures in heavily deformed materials. This paper will highlight the use of high resolution scanning and transmission electron microscopy in combination with APT to better elucidate the microstructure and microchemistry of the filamentary oxidation.

  7. Computational solution of the velocity and wall shear stress distribution inside a left carotid artery under pulsatile flow conditions

    Science.gov (United States)

    Arslan, Nurullah; Turmuş, Hakan

    2014-08-01

    Stroke is still one of the leading causes for death after heart diseases and cancer in all over the world. Strokes happen because an artery that carries blood uphill from the heart to the head is clogged. Most of the time, as with heart attacks, the problem is atherosclerosis, hardening of the arteries, calcified buildup of fatty deposits on the vessel wall. In this study, the fluid dynamic simulations were done in a left carotid bifurcation under the pulsatile flow conditions computationally. Pulsatile flow waveform is given in the paper. In vivo geometry and boundary conditions were obtained from a patient who has stenosis located at external carotid artery (ECA) and internal carotid artery (ICA) of his common carotid artery (CCA). The location of critical flow fields such as low wall shear stress (WSS), stagnation regions and separation regions were detected near the highly stenosed region and at branching region.

  8. Low-dose dobutamine stress echocardiography to assess left ventricular contractile reserve for cardiac resynchronization therapy: data from the Low-Dose Dobutamine Stress Echocardiography to Predict Cardiac Resynchronization Therapy Response (LODO-CRT) trial.

    Science.gov (United States)

    Iacopino, Saverio; Gasparini, Maurizio; Zanon, Francesco; Dicandia, Cosimo; Distefano, Giuseppe; Curnis, Antonio; Donati, Roberto; Neja, Carlo P; Calvi, Valeria; Davinelli, Mario; Novelli, Vanessa; Muto, Carmine

    2010-01-01

    Cardiac resynchronization therapy (CRT) is an effective methodology indicated in selected heart failure patients. Identifying responders to the therapy is still challenging. Most studies report that at least 30% of the patients are nonresponders. Baseline characteristics of the Low-Dose Dobutamine Stress Echocardiography to Predict Cardiac Resynchronization Therapy Response (LODO-CRT) trial population are presented. The study investigates dobutamine stress echocardiography's role in predicting CRT response. Two hundred seventy-one CRT candidates were studied. Mean age was 67+/-10 years, 69% were male, 96% had New York Heart Association class III disease, and 39% had heart failure of ischemic etiology. Mean QRS and left ventricular ejection fraction were 146+/-24 ms and 26%+/-6%, respectively. Seventy-seven percent of participants showed contractile reserve. Left ventricular end-diastolic volume was shown to be independently associated with contractile reserve presence. In particular, more dilated ventricles are associated with a lower chance of having contractile reserve. The LODO-CRT trial enrolled a cohort of patients fulfilling criteria for CRT. Dobutamine stress echocardiography was highly feasible and safe in this population. Contractile reserve was associated with healthier ventricles. (c) 2010 Wiley Periodicals, Inc.

  9. Avaliação quantitativa da movimentação parietal regional do ventrículo esquerdo na endomiocardiofibrose Quantitative assessment of left ventricular regional wall motion in endomyocardial fibrosis

    Directory of Open Access Journals (Sweden)

    Charles Mady

    2005-03-01

    Full Text Available OBJETIVO: Analisar a movimentação parietal regional do ventrículo esquerdo (VE em pacientes com endomiocardiofibrose (EMF. MÉTODOS: Estudados 88 pacientes, 59 do sexo feminino, com idade média de 39±13 anos (variação de 9 a 65 com evidência ecocardiográfica e angiográfica de EMF do VE. A intensidade da deposição de tecido fibroso na cineventriculografia contrastada foi classificada como discreta, moderada ou importante. A fração de ejeção global do ventrículo esquerdo (FEVE foi determinada pelo método área-comprimento por meio da ventriculografia. O movimento foi medido em 100 cordas eqüidistantes e perpendiculares à linha média desenhada no meio dos contornos diastólico e sistólico finais e normalizadas para o tamanho cardíaco. Analisaram-se cinco segmentos do VE: A - apical; AL - ântero-lateral; AB - ântero-basal; IA - ínfero-apical; IB - ínfero-basal. A anormalidade foi expressa em unidades de desvio padrão do movimento médio em uma população de referência normal, composta por 103 pacientes com VE normal, conforme dados de clínica, eletrocardiograma e padrões angiográficos. RESULTADOS: A FEVE média foi de 0,47±0,12. O envolvimento de tecido fibroso do VE foi discreto em 12 pacientes, moderado em 40 e importante em 36. As regiões com pior movimentação parietal foram A (-1,4±1,6 desvio-padrão/cordas e IA (-1,6±1,8 desvio-padrão/cordas comparadas com AB (-0,3±1,9 desvio-padrão /cordas, AL (-0,5±1,8 desvio-padrão/cordas e IB (-0,9±1,3 desvio-padrão/cordas. Não se observou relação entre a intensidade de envolvimento do tecido fibroso e a manutenção parietal regional. CONCLUSÃO : Existe alteração da movimentação parietal regional na EMF e é independente da intensidade de deposição de tecido fibroso avaliada qualitativamente. O envolvimento não uniforme do VE deve ser levado em conta no planejamento cirúrgico dessa doença.OBJECTIVE: To analyze left ventricular (LV regional wall

  10. Short-axis epicardial volume change is a measure of cardiac left ventricular short-axis function, which is independent of myocardial wall thickness.

    Science.gov (United States)

    Ugander, Martin; Carlsson, Marcus; Arheden, Håkan

    2010-02-01

    Fractional shortening (FS) by echocardiography is considered to represent the short-axis contribution to the stroke volume (SV), also called short-axis function. However, FS is mathematically coupled to the amount of myocardium, since it rearranges during atrioventricular plane displacement (AVPD). The SV is the sum of the volumes generated by 1) reduction in outer volume of the heart, and 2) inner AVPD. The long-axis contribution to the SV is generated by AVPD, and thus the short-axis contribution is the remaining outer volume change of the heart, which should be unrelated to myocardial wall thickness. We hypothesized that both endocardial and midwall shortening indexed to SV are dependent on myocardial wall thickness, whereas epicardial volume change (EVC) indexed to SV is not. Twelve healthy volunteers (normals), 12 athletes, and 12 patients with dilated cardiomyopathy (ejection fraction EVC was defined as SV minus long-axis function. Endocardial and midwall shortening were measured in a midventricular short-axis slice. Endocardial shortening/SV and midwall shortening/SV both varied in relation to end-diastolic myocardial wall thickness (R(2) = 0.16, P = 0.008 and R(2) = 0.14, P = 0.012, respectively), whereas EVC/SV did not (R(2) = 0.00, P = 0.37). FS is dependent on myocardial wall thickness, whereas EVC is not and therefore represents true short-axis function. This is not surprising considering that FS is mainly caused by rearrangement of myocardium secondary to long-axis function. FS is therefore not synonymous with short-axis function.

  11. Dobutamine stress echocardiography and technetium-99m-tetrofosmin/fluorine 18-fluorodeoxyglucose single-photon emission computed tomography and influence of resting ejection fraction to assess myocardial viability in patients with severe left ventricular dysfunction and healed myocardial infarction.

    Science.gov (United States)

    Rambaldi, R; Poldermans, D; Bax, J J; Boersma, E; Valkema, R; Elhendy, A; Vletter, W B; Fioretti, P M; Roelandt, J R; Krenning, E P

    1999-07-15

    The purpose of this study was to compare 2 different techniques--dobutamine-atropine stress echocardiography (DSE) and dual-isotope simultaneous acquisition (technetium-99-m-tetrofosmin/fluorine 18-fluorodeoxyglucose) single-photon emission computed tomography (DISA-SPECT)--for assessment of viable myocardium. One hundred ten patients (mean age 55 +/- 9 years) with left ventricular (LV) dysfunction (mean LV ejection fraction 27 +/- 13%) underwent both DISA-SPECT and DSE. A 16-segment scoring model was adopted for both techniques. Four types of wall motion during DSE were assessed: (1) biphasic, improvement at low dose (10 microg/kg/min) with worsening at high dose; (2) worsening, deterioration without initial improvement; (3) sustained, persistent or late improvement; and (4) no change. Viability criteria were biphasic, worsening, and sustained improvement with DSE. Viability criteria with DISA-SPECT were normal perfusion and metabolism (normal), concordantly mildly reduced perfusion and metabolism (subendocardial scar), or severely reduced perfusion and increased metabolism (mismatch). Myocardium was considered nonviable with DSE in case of unchanged wall motion, or moderate reduction or absence in both technetium-99m-tetrofosmin perfusion and fluorodeoxyglucose uptake with DISA-SPECT. Of 1,756 of 1,760 analyzable LV segments, 1,373 (78%) had severe wall motion abnormalities at baseline (severe hypokinesia, akinesia, or dyskinesia). Of these abnormal segments, 282 (21%) were considered viable during DSE (63 [5%] with biphasic response, 47 [3%] with ischemia, and 172 [13%]) with sustained improvement, whereas 1,091 (79%) were considered nonviable. With DISA-SPECT, 396 (29%) segments were considered viable (312 [23%] with matched perfusion/metabolism and 84 [6%] with mismatch), whereas 977 segments (71%) were considered nonviable. Both techniques showed agreement for viability in 201 segments and 896 were concordantly classified as nonviable. Disagreement was

  12. Static pressure and wall shear stress distributions in air flow in a seven wire-wrapped rod bundle

    OpenAIRE

    Fernandez y Fernandez, Elói; Carajilescov, Pedro

    2000-01-01

    An experimental investigation is performed in a turbulent flow in a seven wire-wrapped rod bundle, mounted in an open air facility. Static pressure distributions are measured on central and peripheral rods. By using a Preston tube, the wall shear stress profiles are experimentally obtained along the perimeter of the rods. The geometric parameters of the test section are P/D=1.20 and H/D=15. The measuring section is located at L/D=40 from the air inlet. It is observed that the dimensionless st...

  13. Effect of obesity reduction on preservation of heart function and attenuation of left ventricular remodeling, oxidative stress and inflammation in obese mice.

    Science.gov (United States)

    Wang, Hui-Ting; Liu, Chu-Feng; Tsai, Tzu-Hsien; Chen, Yung-Lung; Chang, Hsueh-Wen; Tsai, Ching-Yen; Leu, Steve; Zhen, Yen-Yi; Chai, Han-Tan; Chung, Sheng-Ying; Chua, Sarah; Yen, Chia-Hung; Yip, Hon-Kan

    2012-07-11

    Obesity is an important cardiovascular risk factor. This study tested the effect of obesity reduction on preserving left ventricular ejection fraction (LVEF) and attenuating inflammation, oxidative stress and LV remodeling in obese mice. Eight-week-old C57BL/6 J mice (n=24) were equally divided into control (fed a control diet for 22 weeks), obesity (high-fat diet, 22 weeks), and obese reduction (OR) (high-fat diet, 14 weeks; then control diet, 8 weeks). Animals were sacrificed at post 22-week high-fat diet and the LV myocardium collected. Heart weight, body weight, abdominal-fat weight, total cholesterol level and fasting blood glucose were higher in obesity than in control and OR (all pobesity than in control and OR (all pobesity as compared with control and OR (all pobesity than in control and OR (all pobesity.

  14. Left atrial and ventricular function during dobutamine and glycopyrrolate stress in healthy young and elderly as evaluated by cardiac magnetic resonance

    DEFF Research Database (Denmark)

    Ahtarovski, Kiril A; Iversen, Kasper K; Lønborg, Jacob T

    2012-01-01

    rates (LVPFRs). Both at rest and during PS, LA maximum and minimum volumes were similar in the groups, whereas middiastolic volume was higher in the elderly. During PS, a marked decrease in LA passive emptying function and a corresponding increase in LA active emptying function were seen in the elderly......The aim of this study is to describe phasic volume changes of the left atrium (LA) in healthy young and elderly subjects at rest and during pharmacological stress (PS). LA maximum size is related to cardiovascular mortality. LA has passive, active, and conduit function for left ventricular (LV......) filling. We hypothesized that changes in LV compliance from normal aging are reflected in LA volume changes and that PS will augment these differences. We enrolled twenty young (20-30 yr) and twenty elderly (60-70 yr) healthy subjects and measured their LV and LA volumes by cardiac magnetic resonance...

  15. Anteroapical stunning and left ventricular outflow tract obstruction.

    Science.gov (United States)

    Villareal, R P; Achari, A; Wilansky, S; Wilson, J M

    2001-01-01

    Dynamic left ventricular outflow tract (LVOT) obstruction is typically observed in the setting of hypertrophic cardiomyopathy. It has also been reported with concentric LV hypertrophy, excessive sympathetic stimulation, and acute myocardial infarction. We describe 3 patients with chest discomfort after emotional stress, who had pronounced abnormalities on electrocardiograms, insignificant obstructive coronary disease and hemodynamic instability with LVOT obstruction, and regional wall motion abnormalities. Suppression of contractility with beta-blockers resulted in resolution of the gradient and in clinical improvement. On follow-up, functional recovery was excellent, and ventricular function had normalized. The conditions and mechanisms that may produce this sequence of events are discussed. The most probable scenario is that an acute ischemic insult secondary to vasospasm, LV stunning, and acute geometric remodeling produced a substrate for LVOT obstruction that was exacerbated by basal LV hypercontractility. The importance of this observation is that routine treatment of cardiogenic shock cannot be used and that conservative management results in excellent prognosis.

  16. Left Ventricular Thrombosis in Ulcerative Colitis

    Directory of Open Access Journals (Sweden)

    Tarek Saleh

    2010-07-01

    Full Text Available Left ventricular thrombi usually occur in the setting of an acute myocardial infarction, left ventricular aneurysm, or dilated cardiomyopathy. In the absence of ventricular wall motion abnormalities, they are rare. This report describes a patient with ulcerative colitis in whom two-dimensional echocardiography revealed a left intraventricular mass. Thrombosis in ulcerative colitis is a serious condition and can occur in a very young population. This case also shows that left ventricular thrombi can occur in the active setting of ulcerative colitis.

  17. Infection related stress adaptations in the secretome and wall proteome of Candida albicans

    NARCIS (Netherlands)

    Sorgo, A.G.

    2013-01-01

    Alice Sorgo's main research question concerns the adaptability of the wall proteome and secretome of the opportunistic pathogenic fungus Candida albicans. The question is how do these subproteomes adapt to environmental stess (high temperatures, iron restriction, antifungal drugs) and how do these

  18. Effect of Exercise Training and L-arginine on Oxidative Stress and Left Ventricular Function in the Post-ischemic Failing Rat Heart.

    Science.gov (United States)

    Ranjbar, Kamal; Nazem, Farzad; Nazari, Afshin

    2016-04-01

    The aim of the present study was to evaluate the effect of exercise training (ET) and L-arginine on oxidative stress and ventricular function in rat with myocardial infarction (MI). Four weeks after the surgical procedures, 40 Wistar male rats were randomized to the following groups: MI-sedentary (Sed); MI-exercise (Ex); MI-sedentary + L-arginine (Sed + LA); and MI-exercise + L-arginine (Ex + LA); the rats were subjected to aerobic training in the form of treadmill running. Rats in the L-arginine-treated groups drank water containing 4 % L-arginine. Before and after the training program, all subjects underwent resting echocardiography. Catalase (CAT) glutathione peroxidase (GPx), malondialdehyde (MDA) and myeloperoxidase (MPO) were measured. Cardiac output, stroke volume and fractional shortening in Ex and Ex + LA groups significantly increased in comparison with the Sed group. Cardiac systolic function indices in Ex + LA group were significantly greater than Ex group. Also, GPx activity and MDA, respectively, increased and decreased in response to ET, but no change was observed in MPO and CAT. These results suggest that ET increased LV function by decreasing oxidative stress and increasing antioxidant defense system in rats with MI. In addition in response to training, L-arginine appears to have additive effect on cardiac function, but have no effect on oxidative stress indices.

  19. Stress in closed thin-walled tubes of single box subjected by shear forces and application to airfoils

    Directory of Open Access Journals (Sweden)

    Zebbiche Toufik

    2014-09-01

    Full Text Available The presented work is to develop a numerical computation program to determine the distribution of the shear stress to shear in closed tubes with asymmetric single thin wall section with a constant thickness and applications to airfoils and therefore determining the position and value of the maximum stress. In the literature, there are exact analytical solutions only for some sections of simple geometries such as circular section. Hence our interest is focused on the search of approximate numerical solutions for more complex sections used in aeronautics. In the second stage the position of the shear center is determined so that the section does not undergo torsion. The analytic function of the boundary of the airfoil is obtained by using the cubic spline interpolation since it is given in the form of tabulated points.

  20. The relationship of hyperinsulinemic state to left ventricular hypertrophy, microalbuminuria, and physical fitness in borderline and mild hypertension.

    Science.gov (United States)

    Tomiyama, H; Doba, N; Kushiro, T; Yamashita, M; Kanmatsuse, K; Kajiwara, N; Yoshida, H; Hinohara, S

    1997-06-01

    The relationship of the hyperinsulinemic state to left ventricular hypertrophy, left ventricular geometric patterns, microalbuminuria, and physical fitness were studied in 52 middle-aged unmedicated men with borderline and mild hypertension. Left ventricular mass index and relative wall thickness were assessed by echocardiography. Physical fitness was determined by symptom-limited maximal treadmill stress testings. The urinary concentration of microalbumin and C-peptide was measured in 24-h urine samples by radioimmunoassey. The 24-h urinary C-peptide excretion rate was correlated with left ventricular mass index (r = 0.46), relative wall thickness (r = 0.41), treadmill time (r = -0.35), normalized treadmill time (r = -0.52), systolic blood pressure at peak exercise (r = 0.29), and 24-h urinary microalbumin excretion (r = 0.48). Stepwise multiple regression analysis identified the left ventricular mass index, the 24-h urinary albumin excretion, and the normalized treadmill time as variables in the equation for the 24-h urinary C-peptide excretion. Thus, the hyperinsulinemic state is related to left ventricular hypertrophy, microalbuminuria, and impaired physical fitness in patients with borderline and mild hypertension.

  1. MR imaging of the heart in patients after myocardial infarction: effect of increasing intersection gap on measurements of left ventricular volume, ejection fraction, and wall thickness.

    Science.gov (United States)

    Cottin, Y; Touzery, C; Guy, F; Lalande, A; Ressencourt, O; Roy, S; Walker, P M; Louis, P; Brunotte, F; Wolf, J E

    1999-11-01

    To determine the extent to which the number of planes imaged at magnetic resonance (MR) imaging could be reduced without modifying the calculated volume and thickness of the left ventricle. Sixty-one patients were examined after a myocardial infarction. The whole left ventricle was imaged by using 5-mm contiguous breath-hold cine MR short-axis sections with no gap (SAng) (two-dimensional fast low-angle shot sequence, 9/4.8 [repetition time msec/echo time msec]). The effect of omitting one section in two (short-axis sections with 5-mm gap [SA5 mm]) or two sections in three (short-axis sections with 10-mm gap [SA10 mm]) was studied. In the comparison of SA5 mm or SA10 mm with respect to the reference SAng, the standard error of the estimate (SEE) for the diastolic volume did not exceed the 6.1% interobserver SEE, and the SEE for the ejection fraction remained lower than the 3% interobserver SEE. The measured wall thickness was not affected. In addition, six simple geometric models were compared with SAng and yielded an SEE of 9.5%-28.1% for the diastolic volume and 3.8%-13.3% for the ejection fraction. In the study of left ventricles with heterogeneous contractility, short-axis imaging is more accurate than geometric modeling and permits wall thickness measurements when an intersection gap of 5 or 10 mm is used.

  2. Conjugate transfer of heat and mass in unsteady flow of a micropolar fluid with wall couple stress

    Science.gov (United States)

    Khalid, Asma; Khan, Ilyas; Khan, Arshad; Shafie, Sharidan

    2015-12-01

    This is an attempt to investigate the unsteady flow of a micropolar fluid with free convection caused due to temperature and concentration differences. Micropolar fluid is taken over a vertical plate oscillating in its own plane. Wall couple stress is engaged at the bounding plate together with isothermal temperature and constant mass diffusion. Problem is modelled in terms of coupled partial differential equations together with some physical conditions and then written in non-dimensional form. Exact solutions are determined using the Laplace transform method. For convenience, they are expressed in simplified form using exponential functions and complementary error functions. Using computational software MATHCAD, analytical results of velocity, temperature, microrotation and concentration are plotted in graphs and discussed for various embedded parameters. Results of skin friction, wall couple stress, rate of heat transfer (Nusselt number) and rate of mass transfer (Sherwood number) are also evaluated. Present results of micropolar fluid are graphically compared with published results of Newtonian fluid. It is found that micropolar fluid velocity is smaller than Newtonian fluid.

  3. Conjugate transfer of heat and mass in unsteady flow of a micropolar fluid with wall couple stress

    Directory of Open Access Journals (Sweden)

    Asma Khalid

    2015-12-01

    Full Text Available This is an attempt to investigate the unsteady flow of a micropolar fluid with free convection caused due to temperature and concentration differences. Micropolar fluid is taken over a vertical plate oscillating in its own plane. Wall couple stress is engaged at the bounding plate together with isothermal temperature and constant mass diffusion. Problem is modelled in terms of coupled partial differential equations together with some physical conditions and then written in non-dimensional form. Exact solutions are determined using the Laplace transform method. For convenience, they are expressed in simplified form using exponential functions and complementary error functions. Using computational software MATHCAD, analytical results of velocity, temperature, microrotation and concentration are plotted in graphs and discussed for various embedded parameters. Results of skin friction, wall couple stress, rate of heat transfer (Nusselt number and rate of mass transfer (Sherwood number are also evaluated. Present results of micropolar fluid are graphically compared with published results of Newtonian fluid. It is found that micropolar fluid velocity is smaller than Newtonian fluid.

  4. Cardiovascular magnetic resonance tagging of the right ventricular free wall for the assessment of long axis myocardial function in congenital heart disease

    Directory of Open Access Journals (Sweden)

    Chen Sylvia SM

    2011-12-01

    Full Text Available Abstract Background Right ventricular ejection fraction (RV-EF has traditionally been used to measure and compare RV function serially over time, but may be a relatively insensitive marker of change in RV myocardial contractile function. We developed a cardiovascular magnetic resonance (CMR tagging-based technique with a view to rapid and reproducible measurement of RV long axis function and applied it in patients with congenital heart disease. Methods We studied 84 patients: 56 with repaired Tetralogy of Fallot (rTOF; 28 with atrial septal defect (ASD: 13 with and 15 without pulmonary hypertension (RV pressure > 40 mmHG by echocardiography. For comparison, 20 healthy controls were studied. CMR acquisitions included an anatomically defined four chamber cine followed by a cine gradient echo-planar sequence in the same plane with a labelling pre-pulse giving a tag line across the basal myocardium. RV tag displacement was measured with automated registration and tracking of the tag line together with standard measurement of RV-EF. Results Mean RV displacement was higher in the control (26 ± 3 mm than in rTOF (16 ± 4 mm and ASD with pulmonary hypertension (18 ± 3 mm groups, but lower than in the ASD group without (30 ± 4 mm, P Conclusions Measurements of RV long axis displacement by CMR tagging showed more differences between the groups studied than did RV-EF, and was reproducible, quick and easy to apply. Further work is needed to assess its potential use for the detection of longitudinal changes in RV myocardial function.

  5. Relation of Left Ventricular Mass and Infarct Size in Anterior Wall ST-Segment Elevation Acute Myocardial Infarction (from the EMBRACE STEMI Clinical Trial).

    Science.gov (United States)

    Daaboul, Yazan; Korjian, Serge; Weaver, W Douglas; Kloner, Robert A; Giugliano, Robert P; Carr, Jim; Neal, Brandon J; Chi, Gerald; Cochet, Madeleine; Goodell, Laura; Michalak, Nathan; Rusowicz-Orazem, Luke; Alkathery, Turky; Allaham, Haytham; Routray, Sujit; Szlosek, Donald; Jain, Purva; Gibson, C Michael

    2016-09-01

    Biomarker measures of infarct size and myocardial salvage index (MSI) are important surrogate measures of clinical outcomes after a myocardial infarction. However, there is variability in infarct size unaccounted for by conventional adjustment factors. This post hoc analysis of Evaluation of Myocardial Effects of Bendavia for Reducing Reperfusion Injury in Patients With Acute Coronary Events (EMBRACE) ST-Segment Elevation Myocardial Infarction (STEMI) trial evaluates the association between left ventricular (LV) mass and infarct size as assessed by areas under the curve for creatine kinase-MB (CK-MB) and troponin I release over the first 72 hours (CK-MB area under the curve [AUC] and troponin I [TnI] AUC) and the MSI. Patients with first anterior STEMI, occluded left anterior descending artery, and available LV mass measurement in EMBRACE STEMI trial were included (n = 100) (ClinicalTrials.govNCT01572909). MSI, end-diastolic LV mass on day 4 cardiac magnetic resonance, and CK-MB and troponin I concentrations were evaluated by a core laboratory. After saturated multivariate analysis, dominance analysis was performed to estimate the contribution of each independent variable to the predicted variance of each outcome. In multivariate models that included age, gender, body surface area, lesion location, smoking, and ischemia time, LV mass remained independently associated with biomarker measures of infarct size (CK-MB AUC p = 0.02, TnI AUC p = 0.03) and MSI (p = 0.003). Dominance analysis demonstrated that LV mass accounted for 58%, 47%, and 60% of the predicted variances for CK-MB AUC, TnI AUC, and MSI, respectively. In conclusion, LV mass accounts for approximately half of the predicted variance in biomarker measures of infarct size. It should be considered as an adjustment variable in studies evaluating infarct size. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Quercetin protects Saccharomyces cerevisiae against oxidative stress by inducing trehalose biosynthesis and the cell wall integrity pathway.

    Directory of Open Access Journals (Sweden)

    Rita Vilaça

    Full Text Available BACKGROUND: Quercetin is a naturally occurring flavonol with antioxidant, anticancer and anti-ageing properties. In this study we aimed to identify genes differentially expressed in yeast cells treated with quercetin and its role in oxidative stress protection. METHODS: A microarray analysis was performed to characterize changes in the transcriptome and the expression of selected genes was validated by RT-qPCR. Biological processes significantly affected were identified by using the FUNSPEC software and their relevance in H(2O(2 resistance induced by quercetin was assessed. RESULTS: Genes associated with RNA metabolism and ribosome biogenesis were down regulated in cells treated with quercetin, whereas genes associated with carbohydrate metabolism, endocytosis and vacuolar proteolysis were up regulated. The induction of genes related to the metabolism of energy reserves, leading to the accumulation of the stress protectant disaccharide trehalose, and the activation of the cell wall integrity pathway play a key role in oxidative stress resistance induced by quercetin. CONCLUSIONS: These results suggest that quercetin may act as a modulator of cell signaling pathways related to carbohydrate metabolism and cell integrity to exert its protective effects against oxidative stress.

  7. Importance of material parameters and strain energy function on the wall stresses in the left ventricle.

    Science.gov (United States)

    Behdadfar, Sareh; Navarro, Laurent; Sundnes, Joakim; Maleckar, Molly M; Avril, Stéphane

    2017-08-01

    Patient-specific estimates of the stress distribution in the left ventricles (LV) may have important applications for therapy planning, but computing the stress generally requires knowledge of the material behaviour. The passive stress-strain relation of myocardial tissue has been characterized by a number of models, but material parameters (MPs) remain difficult to estimate. The aim of this study is to implement a zero-pressure algorithm to reconstruct numerically the stress distribution in the LV without precise knowledge of MPs. We investigate the sensitivity of the stress distribution to variations in the different sets of constitutive parameters. We show that the sensitivity of the LV stresses to MPs can be marginal for an isotropic constitutive model. However, when using a transversely isotropic exponential strain energy function, the LV stresses become sensitive to MPs, especially to the linear elastic coefficient before the exponential function. This indicates that in-vivo identification efforts should focus mostly on this MP for the development of patient-specific finite-element analysis.

  8. Cell wall modifications in maize pulvini in response to gravitational stress.

    Science.gov (United States)

    Zhang, Qisen; Pettolino, Filomena A; Dhugga, Kanwarpal S; Rafalski, J Antoni; Tingey, Scott; Taylor, Jillian; Shirley, Neil J; Hayes, Kevin; Beatty, Mary; Abrams, Suzanne R; Zaharia, L Irina; Burton, Rachel A; Bacic, Antony; Fincher, Geoffrey B

    2011-08-01

    Changes in cell wall polysaccharides, transcript abundance, metabolite profiles, and hormone concentrations were monitored in the upper and lower regions of maize (Zea mays) pulvini in response to gravistimulation, during which maize plants placed in a horizontal position returned to the vertical orientation. Heteroxylan levels increased in the lower regions of the pulvini, together with lignin, but xyloglucans and heteromannan contents decreased. The degree of substitution of heteroxylan with arabinofuranosyl residues decreased in the lower pulvini, which exhibited increased mechanical strength as the plants returned to the vertical position. Few or no changes in noncellulosic wall polysaccharides could be detected on the upper side of the pulvinus, and crystalline cellulose content remained essentially constant in both the upper and lower pulvinus. Microarray analyses showed that spatial and temporal changes in transcript profiles were consistent with the changes in wall composition that were observed in the lower regions of the pulvinus. In addition, the microarray analyses indicated that metabolic pathways leading to the biosynthesis of phytohormones were differentially activated in the upper and lower regions of the pulvinus in response to gravistimulation. Metabolite profiles and measured hormone concentrations were consistent with the microarray data, insofar as auxin, physiologically active gibberellic acid, and metabolites potentially involved in lignin biosynthesis increased in the elongating cells of the lower pulvinus.

  9. Cell Wall Modifications in Maize Pulvini in Response to Gravitational Stress1[W][OA

    Science.gov (United States)

    Zhang, Qisen; Pettolino, Filomena A.; Dhugga, Kanwarpal S.; Rafalski, J. Antoni; Tingey, Scott; Taylor, Jillian; Shirley, Neil J.; Hayes, Kevin; Beatty, Mary; Abrams, Suzanne R.; Zaharia, L. Irina; Burton, Rachel A.; Bacic, Antony; Fincher, Geoffrey B.

    2011-01-01

    Changes in cell wall polysaccharides, transcript abundance, metabolite profiles, and hormone concentrations were monitored in the upper and lower regions of maize (Zea mays) pulvini in response to gravistimulation, during which maize plants placed in a horizontal position returned to the vertical orientation. Heteroxylan levels increased in the lower regions of the pulvini, together with lignin, but xyloglucans and heteromannan contents decreased. The degree of substitution of heteroxylan with arabinofuranosyl residues decreased in the lower pulvini, which exhibited increased mechanical strength as the plants returned to the vertical position. Few or no changes in noncellulosic wall polysaccharides could be detected on the upper side of the pulvinus, and crystalline cellulose content remained essentially constant in both the upper and lower pulvinus. Microarray analyses showed that spatial and temporal changes in transcript profiles were consistent with the changes in wall composition that were observed in the lower regions of the pulvinus. In addition, the microarray analyses indicated that metabolic pathways leading to the biosynthesis of phytohormones were differentially activated in the upper and lower regions of the pulvinus in response to gravistimulation. Metabolite profiles and measured hormone concentrations were consistent with the microarray data, insofar as auxin, physiologically active gibberellic acid, and metabolites potentially involved in lignin biosynthesis increased in the elongating cells of the lower pulvinus. PMID:21697508

  10. Up-Regulation of mRNA Ventricular PRNP Prion Protein Gene Expression in Air Pollution Highly Exposed Young Urbanites: Endoplasmic Reticulum Stress, Glucose Regulated Protein 78, and Nanosized Particles

    Directory of Open Access Journals (Sweden)

    Rodolfo Villarreal-Calderon

    2013-11-01

    Full Text Available Mexico City Metropolitan Area children and young adults exposed to high concentrations of air pollutants including fine and ultrafine particulate matter (PM vs. clean air controls, exhibit myocardial inflammation and inflammasome activation with a differential right and left ventricular expression of key inflammatory genes and inflammasomes. We investigated the mRNA expression levels of the prion protein gene PRNP, which plays an important role in the protection against oxidative stress and metal toxicity, and the glucose regulated protein 78, a key protein in endoplasmic reticulum (ER stress signaling, in ventricular autopsy samples from 30 children and young adults age 19.97 ± 6.8 years with a lifetime of low (n:4 vs. high (n:26 air pollution exposures. Light microscopy and transmission electron microscopy studies were carried out in human ventricles, and electron microscopy studies were also done in 5 young, highly exposed Mexico City dogs. There was significant left ventricular PRNP and bi-ventricular GRP78 mRNA up-regulation in Mexico City young urbanites vs. controls. PRNP up-regulation in the left ventricle was significantly different from the right, p < 0.0001, and there was a strong left ventricular PRNP and GRP78 correlation (p = 0.0005. Marked abnormalities in capillary endothelial cells, numerous nanosized particles in myocardial ER and in abnormal mitochondria characterized the highly exposed ventricles. Early and sustained cardiac ER stress could result in detrimental irreversible consequences in urban children, and while highly complex systems maintain myocardial homeostasis, failure to compensate for chronic myocardial inflammation, oxidative and ER stress, and particles damaging myocardial organelles may prime the development of pathophysiological cardiovascular states in young urbanites. Nanosized PM could play a key cardiac myocyte toxicity role.

  11. Determinants of the response of left ventricular ejection fraction to vasodilator stress in electrocardiographically gated {sup 82}rubidium myocardial perfusion PET

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Tracy L.Y.; Merrill, Jennifer; Bengel, Frank M. [Johns Hopkins University, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, Baltimore, MD (United States); Volokh, Lana [GE Healthcare, Haifa (Israel)

    2008-02-15

    Myocardial perfusion imaging with {sup 82}Rb PET allows for ECG-gated studies to be obtained early after radiotracer injection, capturing ventricular function close to peak pharmacologic action of dipyridamole. This is different from gated SPECT and may potentially provide additional diagnostic information. We sought to identify potential correlates of the PET-derived ejection fraction response to vasodilator stress. One hundred ten consecutive patients undergoing {sup 82}Rb PET myocardial perfusion imaging during evaluation for coronary artery disease were included. Using a GE Discovery STRx PET-CT scanner, ECG-gated images (eight bins) were obtained at rest and 4 min after dipyridamole infusion, 90 s after infusion of 1,480-2,220 MBq of {sup 82}Rb. Summed rest, stress, and difference scores (SRS, SSS, and SDS) were determined using a five-point scoring system and 20-segment model. Ejection fraction was calculated using automated QGS software. Significant reversibility (SDS {>=} 4) was found in 23 patients (21%). Mean LVEF in all patients was 47 {+-} 13% at rest and 53 {+-} 13% during dipyridamole. LVEF increased in 89 patients, and decreased in 17 patients during vasodilation. The change in LVEF was inversely correlated with SDS (r = -0.26; p = 0.007). Additionally, it was inversely correlated with resting LVEF (r = -0.20; p = 0.03) and SSS (r = -0.25; p = 0.009). No significant correlations were observed with SRS, heart rate, blood pressure, age, hypertension, hypercholesterolemia, or pretest likelihood of disease. At multivariate regression analysis, SDS was an independent predictor of the change in LVEF. Gated {sup 82}Rb PET during pharmacologic stress allows for assessment of the functional response to vasodilation. The magnitude of LVEF increase is determined by stress perfusion/reversible perfusion defects. Functional response to hyperemia may thus be incorporated in future evaluations of diagnostic and prognostic algorithms based on {sup 82}Rb PET. (orig.)

  12. Prevalence and long-term prognosis of patients with complete bundle branch block (right or left bundle branch) with normal left ventricular ejection fraction referred for stress echocardiography.

    Science.gov (United States)

    Supariwala, Azhar A; Po, Jose Ricardo F; Mohareb, Sameh; Aslam, Farhan; Kaddaha, Firas; Mian, Zainab I; Chaudhry, Farhan; Otokiti, Ahmed; Chaudhry, Farooq A

    2015-03-01

    The prognostic value of stress echocardiography (SE) in patients with complete bundle branch blocks (BBB) with normal left ventricular ejection fraction (LVEF) has not been well described. We sought to determine the prognostic value of SE in patients with BBB and normal LVEF. We analyzed 7214 patients (58 ± 14 years; 57% female) with a mean follow-up time of 9 ± 4 years. Dobutamine SE was performed in 51% of patients and exercise SE was performed in 49%. All-cause mortality data were obtained from the Social Security Death Index. There were 222 (3%) patients with right bundle branch block (RBBB) and 50 (0.7%) patients with left bundle branch block (LBBB). Patients with LBBB were 3 times more likely to have an abnormal stress test after adjusting for age, gender, mode of stress test, and coronary artery disease risk factors (OR = 3.3; 95% CI: 1.86-5.92; P < 0.001). The mortality rates were 4.5%/year for patients with LBBB, 2.5%/year for patients with RBBB, and 1.9%/year for patients without BBB (P < 0.001). Among patients with a normal SE, those with LBBB had similar mortality to those without LBBB (HR = 0.9; 95% CI: 0.4-2.2; P = 0.8). Patients with LBBB and abnormal SE had more than 2 times greater risk of all-cause mortality (HR = 2.4; 95% CI: 1.4-4.2; P = 0.002). A normal stress echocardiogram in LBBB is associated with benign prognosis while those with LBBB and abnormal SE have the worst outcomes. © 2014, Wiley Periodicals, Inc.

  13. Diastolic Left Ventricular Dysfunction : A Clinical Appraisal

    NARCIS (Netherlands)

    Bronzwaer, J.G.F.

    2003-01-01

    Diastolic left ventricular (LV) distensibility is determined by the material properties of the LV wall and by LV geometry (i.e., LV shape, LV volume and LV wall thickness). These material properties are influenced both by the physical structure of the LV myocardium and by the dynamic process of

  14. Humanin is expressed in human vascular walls and has a cytoprotective effect against oxidized LDL-induced oxidative stress

    Science.gov (United States)

    Bachar, Adi R.; Scheffer, Lea; Schroeder, Andreas S.; Nakamura, Hiromi K.; Cobb, Laura J.; Oh, Yun K.; Lerman, Lilach O.; Pagano, Richard E.; Cohen, Pinchas; Lerman, Amir

    2010-01-01

    Aims Humanin (HN) is a 24-amino acid peptide that has been shown to have an anti-apoptotic function against neuronal cell death caused by Alzheimer's disease. Increased oxidative stress, one of the major factors contributing to this cell death, also plays an important role in the inflammatory process of atherosclerosis. The current study was designed to test the hypothesis that HN is expressed in the human vascular wall and may protect against oxidative stress. Methods and results HN expression in the vascular wall was detected by immunostaining in the endothelial cell layer of human internal mammary arteries (n = 5), atherosclerotic coronary arteries (n = 17), and sections of the greater saphenous vein (n = 3). HN mRNA was expressed in the human aortic endothelial cells (HAECs). Cytoprotective effects of HN against oxidative stress were tested in vitro in HAECs. Pre-treatment with 0.1 µM HN reduced oxidized LDL (Ox-LDL)-induced (i) formation of reactive oxygen species by 50%, (ii) apoptosis by ∼50% as determined by TUNEL staining, and (iii) formation of ceramide, a lipid second messenger involved in the apoptosis signalling cascade, by ∼20%. Conclusion The current study demonstrates for the first time the expression of HN in the endothelial cell layer of human blood vessels. Exogenous addition of HN to endothelial cell cultures was shown to be effective against Ox-LDL-induced apoptosis. These findings suggest that HN may play a role and may have a protective effect in early atherosclerosis in humans. PMID:20562421

  15. Inhibition of ADAMTS-13 by Doxycycline Reduces von Willebrand Factor Degradation During Supraphysiological Shear Stress: Therapeutic Implications for Left Ventricular Assist Device-Associated Bleeding.

    Science.gov (United States)

    Bartoli, Carlo R; Kang, Jooeun; Restle, David J; Zhang, David M; Shabahang, Cameron; Acker, Michael A; Atluri, Pavan

    2015-11-01

    The aim of this study was to investigate a potential therapy for left ventricular assist device (LVAD)-associated bleeding. Nonsurgical bleeding is the most frequent complication of LVAD support. Recent evidence has demonstrated that supraphysiological shear stress from continuous-flow LVADs accelerates von Willebrand factor (vWF) metabolism by the action of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) (the vWF protease). An acquired vWF deficiency causes bleeding. This suggests that ADAMTS-13 is a clinical target to reduce vWF degradation. We tested the hypothesis that inhibition of ADAMTS-13 with doxycycline, an inexpensive, clinically approved drug, reduces vWF degradation during shear stress. Whole blood was collected from human donors (n = 15), and purified, recombinant ADAMTS-13 protein was obtained. An enzyme-linked immunosorbent assay (ELISA) was used to quantify the dose relationship between doxycycline and ADAMTS-13 activity prior to shear stress (n = 10). To determine the effect of shear stress, plasma and recombinant ADAMTS-13 were exposed to LVAD-like supraphysiological shear stress (approximately 175 dyne/cm(2)). vWF multimers and degradation fragments were characterized with electrophoresis and immunoblotting (n = 10). Förster resonance energy transfer was used to quantify plasma ADAMTS-13 activity (n = 10). An ELISA was used to quantify vWF:collagen binding activity. Platelet aggregometry was performed with adenosine 5'-diphosphate, collagen, and ristocetin (vWF-platelet pathway) agonism (n = 10). Doxycycline significantly decreased plasma ADAMTS-13 activity (p = 0.01) and the activity of recombinant human ADAMTS-13 protein by 21%. After plasma was exposed to shear stress, the same pattern of vWF degradation was observed as previously reported for LVAD patients, and vWF:collagen binding activity decreased significantly (p = 0.002). Doxycycline significantly decreased ADAMTS-13 activity (p = 0.04) and

  16. Acetylation of cell wall is required for structural integrity of the leaf surface and exerts a global impact on plant stress responses

    DEFF Research Database (Denmark)

    Nafisi, Majse; Stranne, Maria; Fimognari, Lorenzo

    2015-01-01

    The epidermis on leaves protects plants from pathogen invasion and provides a waterproof barrier. It consists of a layer of cells that is surrounded by thick cell walls, which are partially impregnated by highly hydrophobic cuticular components. We show that the Arabidopsis T-DNA insertion mutant...... acetylation is essential for maintaining the structural integrity of leaf epidermis, and that reduction of cell wall acetylation leads to global stress responses in Arabidopsis....

  17. Constrictive pericarditis presenting with an outpouching of the right ventricle free wall simulating an aneurysmal dilatation

    Science.gov (United States)

    Ocak, I; Turkbey, B; Lacomis, J M

    2011-01-01

    We present a case of constrictive pericarditis resulting in an outpouching of the right ventricular free wall, simulating a right ventricular free wall aneurysm. The present case is, to the best of our knowledge, the first reported right ventricular free wall aneurysm-like outpouching adjacent to surrounding regions of thickened pericardium in a patient with constrictive pericarditis. PMID:21325359

  18. Dilation and Hypertrophy: A Cell-Based Continuum Mechanics Approach Towards Ventricular Growth and Remodeling

    Science.gov (United States)

    Ulerich, J.; Göktepe, S.; Kuhl, E.

    This manuscript presents a continuum approach towards cardiac growth and remodeling that is capable to predict chronic maladaptation of the heart in response to changes in mechanical loading. It is based on the multiplicative decomposition of the deformation gradient into and elastic and a growth part. Motivated by morphological changes in cardiomyocyte geometry, we introduce an anisotropic growth tensor that can capture both hypertrophic wall thickening and ventricular dilation within one generic concept. In agreement with clinical observations, we propose wall thickening to be a stress-driven phenomenon whereas dilation is introduced as a strain-driven process. The features of the proposed approach are illustrated in terms of the adaptation of thin heart slices and in terms overload-induced dilation in a generic bi-ventricular heart model.

  19. The Arabidopsis leucine-rich repeat receptor kinase MIK2/LRR-KISS connects cell wall integrity sensing, root growth and response to abiotic and biotic stresses.

    Science.gov (United States)

    Van der Does, Dieuwertje; Boutrot, Freddy; Engelsdorf, Timo; Rhodes, Jack; McKenna, Joseph F; Vernhettes, Samantha; Koevoets, Iko; Tintor, Nico; Veerabagu, Manikandan; Miedes, Eva; Segonzac, Cécile; Roux, Milena; Breda, Alice S; Hardtke, Christian S; Molina, Antonio; Rep, Martijn; Testerink, Christa; Mouille, Grégory; Höfte, Herman; Hamann, Thorsten; Zipfel, Cyril

    2017-06-01

    Plants actively perceive and respond to perturbations in their cell walls which arise during growth, biotic and abiotic stresses. However, few components involved in plant cell wall integrity sensing have been described to date. Using a reverse-genetic approach, we identified the Arabidopsis thaliana leucine-rich repeat receptor kinase MIK2 as an important regulator of cell wall damage responses triggered upon cellulose biosynthesis inhibition. Indeed, loss-of-function mik2 alleles are strongly affected in immune marker gene expression, jasmonic acid production and lignin deposition. MIK2 has both overlapping and distinct functions with THE1, a malectin-like receptor kinase previously proposed as cell wall integrity sensor. In addition, mik2 mutant plants exhibit enhanced leftward root skewing when grown on vertical plates. Notably, natural variation in MIK2 (also named LRR-KISS) has been correlated recently to mild salt stress tolerance, which we could confirm using our insertional alleles. Strikingly, both the increased root skewing and salt stress sensitivity phenotypes observed in the mik2 mutant are dependent on THE1. Finally, we found that MIK2 is required for resistance to the fungal root pathogen Fusarium oxysporum. Together, our data identify MIK2 as a novel component in cell wall integrity sensing and suggest that MIK2 is a nexus linking cell wall integrity sensing to growth and environmental cues.

  20. Rôle of contrast media viscosity in altering vessel wall shear stress and relation to the risk of contrast extravasations.

    Science.gov (United States)

    Sakellariou, Sophia; Li, Wenguang; Paul, Manosh C; Roditi, Giles

    2016-12-01

    Iodinated contrast media (CM) are the most commonly used injectables in radiology today. A range of different media are commercially available, combining various physical and chemical characteristics (ionic state, osmolality, viscosity) and thus exhibiting distinct in vivo behaviour and safety profiles. In this paper, numerical simulations of blood flow with contrast media were conducted to investigate the effects of contrast viscosity on generated vessel wall shear stress and vessel wall pressure to elucidate any possible relation to extravasations. Five different types of contrast for Iodine fluxes ranging at 1.5-2.2gI/s were modelled through 18G and 20G cannulae placed in an ideal vein at two different orientation angles. Results demonstrate that the least viscous contrast media generate the least maximum wall shear stress as well as the lowest total pressure for the same flow rate. This supports the empirical clinical observations and hypothesis that more viscous contrast media are responsible for a higher percentage of contrast extravasations. In addition, results support the clinical hypothesis that a catheter tip directed obliquely to the vein wall always produces the highest maximum wall shear stress and total pressure due to impingement of the contrast jet on the vessel wall. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  1. Exercise-mediated wall shear stress increases mitochondrial biogenesis in vascular endothelium.

    Directory of Open Access Journals (Sweden)

    Boa Kim

    Full Text Available OBJECTIVE: Enhancing structural and functional integrity of mitochondria is an emerging therapeutic option against endothelial dysfunction. In this study, we sought to investigate the effect of fluid shear stress on mitochondrial biogenesis and mitochondrial respiratory function in endothelial cells (ECs using in vitro and in vivo complementary studies. METHODS AND RESULTS: Human aortic- or umbilical vein-derived ECs were exposed to laminar shear stress (20 dyne/cm2 for various durations using a cone-and-plate shear apparatus. We observed significant increases in the expression of key genes related to mitochondrial biogenesis and mitochondrial quality control as well as mtDNA content and mitochondrial mass under the shear stress conditions. Mitochondrial respiratory function was enhanced when cells were intermittently exposed to laminar shear stress for 72 hrs. Also, shear-exposed cells showed diminished glycolysis and decreased mitochondrial membrane potential (ΔΨm. Likewise, in in vivo experiments, mice that were subjected to a voluntary wheel running exercise for 5 weeks showed significantly higher mitochondrial content determined by en face staining in the conduit (greater and lesser curvature of the aortic arch and thoracic aorta and muscle feed (femoral artery arteries compared to the sedentary control mice. Interestingly, however, the mitochondrial biogenesis was not observed in the mesenteric artery. This region-specific adaptation is likely due to the differential blood flow redistribution during exercise in the different vessel beds. CONCLUSION: Taken together, our findings suggest that exercise enhances mitochondrial biogenesis in vascular endothelium through a shear stress-dependent mechanism. Our findings may suggest a novel mitochondrial pathway by which a chronic exercise may be beneficial for vascular function.

  2. Chitin synthase gene FgCHS8 affects virulence and fungal cell wall sensitivity to environmental stress in Fusarium graminearum.

    Science.gov (United States)

    Zhang, Ya-Zhou; Chen, Qing; Liu, Cai-Hong; Liu, Yu-Bin; Yi, Pan; Niu, Ke-Xin; Wang, Yan-Qing; Wang, An-Qi; Yu, Hai-Yue; Pu, Zhi-En; Jiang, Qian-Tao; Wei, Yu-Ming; Qi, Peng-Fei; Zheng, You-Liang

    2016-05-01

    Fusarium graminearum is the major causal agent of Fusarium head blight (FHB) of wheat and barley and is considered to be one of the most devastating plant diseases worldwide. Chitin is a critical component of the fungal cell wall and is polymerized from UDP-N-acetyl-alpha-D-glucosamine by chitin synthase. We characterized FgCHS8, a new class of the chitin synthase gene in F. graminearum. Disruption of FgCHS8 resulted in reduced accumulation of chitin, decreased chitin synthase activity, and had no effect on conidia growth when compared with the wild-type isolate. ΔFgCHS8 had a growth rate comparable to that of the wild-type isolate in vitro. However, ΔFgCHS8 had reduced growth when grown on agar supplemented with either 0.025% SDS or 0.9 mM salicylic acid. ΔFgCHS8 produced significantly less deoxynivalenol and exhibited reduced pathogenicity in wheat spikes. Re-introduction of a functional FgCHS8 gene into the ΔFgCHS8 mutant strain restored the wild-type phenotypes. Fluorescence microscopy revealed that FgCHS8 protein was initially expressed in the septa zone, and then gradually distributed over the entire cellular membrane, indicating that FgCHS8 was required for cell wall development. Our results demonstrated that FgCHS8 is important for cell wall sensitivity to environmental stress factors and deoxynivalenol production in F. graminearum. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  3. The resonance theory of coronary arterial wall stress as an explanation for the distribution of coronary artery disease.

    Science.gov (United States)

    John, Lindsay C H

    2010-05-01

    The coronary arteries are unique within the arterial system in being subject to a continuous oscillatory displacement. It is hypothesised that oscillatory resonance of the coronary arteries occurs when the heart rate is the same as the arteries' Natural Frequency of oscillation. If resonance were to occur then standing waves would exist along the coronary arteries. The sites of the anti-nodes of such standing waves would be the sites of increased wall stress and therefore be expected to be predisposed to disease. Coronary artery resonance would explain the observed increased incidence of disease in the proximal segments of the arteries. It is proposed that coronary artery resonance is a previously unrecognised aetiological factor for coronary artery disease that contributes to its location. If the hypothesis is true then there are potential important consequences for the diagnosis and treatment of the disease.

  4. Wall Shear Stress Restoration in Dialysis Patient's Venous Stenosis: Elucidation via 3D CFD and Shape Optimization

    Science.gov (United States)

    Mahmoudzadeh Akherat, S. M. Javid; Cassel, Kevin; Hammes, Mary; Boghosian, Michael; Illinois Institute of Technology Team; University of Chicago Team

    2016-11-01

    Venous stenosis developed after the growth of excessive neointimal hyperplasia (NH) in chronic dialysis treatment is a major cause of mortality in renal failure patients. It has been hypothesized that the low wall shear stress (WSS) triggers an adaptive response in patients' venous system that through the growth of neointimal hyperplastic lesions restores WSS and transmural pressure, which also regulates the blood flow rate back to physiologically acceptable values which is violated by dialysis treatment. A strong coupling of three-dimensional CFD and shape optimization analyses were exploited to elucidate and forecast this adaptive response which correlates very well topographically with patient-specific clinical data. Based on the framework developed, a medical protocol is suggested to predict and prevent dialysis treatment failure in clinical practice. Supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (R01 DK90769).

  5. Effect on Growth, Photosynthesis, and Oxidative Stress of Single Walled Carbon Nanotubes Exposure to Marine Alga Dunaliella tertiolecta

    Directory of Open Access Journals (Sweden)

    Megha Thakkar

    2016-01-01

    Full Text Available Single walled carbon nanotubes were carboxylated by microwave assisted acid oxidation (f-SWCNTs and examined for their ecotoxicity on marine alga chlorophyte Dunaliella tertiolecta. Toxicity was evaluated based on growth, photosynthetic activities, oxidative stress, and intracellular glutathione in the concentration range of 0.1–20 mg/L f-SWCNT. Physical interactions between the f-SWCNT and alga were examined using light microscopy and scanning electron microscope. Increasing the nanotube concentration increased the toxic effects where growth inhibition was as high as 30%, photosynthetic yield decreased by as much as 18%, and intracellular glutathione reduction reached 95%. The results from f-SWCNTs were somewhat different when compared to our previous study using the same algae and functionalized multiwalled carbon nanotubes, where exposure led to longer lag phase and higher growth rate inhibition.

  6. Effect on Growth, Photosynthesis, and Oxidative Stress of Single Walled Carbon Nanotubes Exposure to Marine Alga Dunaliella tertiolecta.

    Science.gov (United States)

    Thakkar, Megha; Mitra, Somenath; Wei, Liping

    2016-01-01

    Single walled carbon nanotubes were carboxylated by microwave assisted acid oxidation (f-SWCNTs) and examined for their ecotoxicity on marine alga chlorophyte Dunaliella tertiolecta. Toxicity was evaluated based on growth, photosynthetic activities, oxidative stress, and intracellular glutathione in the concentration range of 0.1-20 mg/L f-SWCNT. Physical interactions between the f-SWCNT and alga were examined using light microscopy and scanning electron microscope. Increasing the nanotube concentration increased the toxic effects where growth inhibition was as high as 30%, photosynthetic yield decreased by as much as 18%, and intracellular glutathione reduction reached 95%. The results from f-SWCNTs were somewhat different when compared to our previous study using the same algae and functionalized multiwalled carbon nanotubes, where exposure led to longer lag phase and higher growth rate inhibition.

  7. Mechanisms of Multi-walled Carbon Nanotubes-Induced Oxidative Stress and Genotoxicity in Mouse Fibroblast Cells.

    Science.gov (United States)

    Alarifi, Saud; Ali, Daoud

    2015-01-01

    The extensive production and wide application of carbon nanotubes have made investigations of its toxic potentials necessary. In the present study, we explored the underlying mechanism through which multi-walled carbon nanotubes (MWCNTs) induce toxicity in mouse fibroblast cells (L929). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and neutral red uptake viability assays were used to examine mechanisms of cytotoxicity. Dose and time-dependent cytotoxicity was observed in L929 cells. The MWCNTs significantly increased the generation of reactive oxygen species, lipid peroxidation, superoxide dismutase, and decreased glutathione. It was observed that the MWCNTs induced caspase 3 activity. The highest DNA strand breakage was detected by comet assay at 300 µg/mL of MWCNTs. Thus, the data indicate that MWCNTs induced cytotoxicity and apoptosis in L929 cells via oxidative stress. © The Author(s) 2015.

  8. Direct Assessment of Wall Shear Stress by Signal Intensity Gradient from Time-of-Flight Magnetic Resonance Angiography.

    Science.gov (United States)

    Han, Kap-Soo; Lee, Sang Hyuk; Ryu, Han Uk; Park, Se-Hyoung; Chung, Gyung-Ho; Cho, Young I; Jeong, Seul-Ki

    2017-01-01

    The aim of the study was to calculate the arterial wall signal intensity gradient (SIG) from time-of-flight MR angiography (TOF-MRA) and represent arterial wall shear stress. We developed a new algorithm that uses signal intensity (SI) of a TOF-MRA to directly calculate the signal intensity gradient (SIG). The results from our phantom study showed that the TOF-MRA SIG could be used to distinguish the magnitude of blood flow rate as high (mean SIG ± SD, 2.2 ± 0.4 SI/mm for 12.5 ± 2.3 L/min) and low (0.9 ± 0.3 SI/mm for 8.5 ± 2.6 L/min) in vessels (p SIG values were highly correlated with various flow rates (β = 0.96, p SIG was greater than 0.8 in each section at the carotid artery (p SIG and thereby the WSS. Thus, the TOF-MRA SIG can provide clinicians with an accurate and efficient screening method for making rapid decisions on the risk of vascular disease for a patient in clinical practice.

  9. Beneficial effects of elevating cardiac preload on left-ventricular diastolic function and volume during heat stress

    DEFF Research Database (Denmark)

    Brothers, R M; Pecini, Redi; Dalsgaard, M

    2014-01-01

    Volume loading normalizes tolerance to a simulated hemorrhagic challenge in heat-stressed individuals, relative to when these individuals are thermoneutral. The mechanism(s) by which this occurs is unknown. This project tested two unique hypotheses; that is, the elevation of central blood volume ...

  10. Effects of Argentilactone on the Transcriptional Profile, Cell Wall and Oxidative Stress of Paracoccidioides spp.

    Directory of Open Access Journals (Sweden)

    Felipe Souto Araújo

    2016-01-01

    Full Text Available Paracoccidioides spp., a dimorphic pathogenic fungus, is the etiologic agent of paracoccidioidomycosis (PCM. PCM is an endemic disease that affects at least 10 million people in Latin America, causing severe public health problems. The drugs used against pathogenic fungi have various side effects and limited efficacy; therefore, there is an inevitable and urgent medical need for the development of new antifungal drugs. In the present study, we evaluated the transcriptional profile of Paracoccidioides lutzii exposed to argentilactone, a constituent of the essential oil of Hyptis ovalifolia. A total of 1,058 genes were identified, of which 208 were up-regulated and 850 were down-regulated. Cell rescue, defense and virulence, with a total of 26 genes, was a functional category with a large number of genes induced, including heat shock protein 90 (hsp90, cytochrome c peroxidase (ccp, the hemoglobin ligand RBT5 (rbt5 and superoxide dismutase (sod. Quantitative real-time PCR revealed an increase in the expression level of all of those genes. An enzymatic assay showed a significant increase in SOD activity. The reduced growth of Pbhsp90-aRNA, Pbccp-aRNA, Pbsod-aRNA and Pbrbt5-aRNA isolates in the presence of argentilactone indicates the importance of these genes in the response of Paracoccidioides spp. to argentilactone. The response of the P. lutzii cell wall to argentilactone treatment was also evaluated. The results showed that argentilactone caused a decrease in the levels of polymers in the cell wall. These results suggest that argentilactone is a potential candidate for antifungal therapy.

  11. Effects of Argentilactone on the Transcriptional Profile, Cell Wall and Oxidative Stress of Paracoccidioides spp.

    Science.gov (United States)

    Araújo, Felipe Souto; Coelho, Luciene Melo; Silva, Lívia do Carmo; da Silva Neto, Benedito Rodrigues; Parente-Rocha, Juliana Alves; Bailão, Alexandre Melo; de Oliveira, Cecília Maria Alves; Fernandes, Gabriel da Rocha; Hernández, Orville; Ochoa, Juan Guillermo McEwen; Soares, Célia Maria de Almeida; Pereira, Maristela

    2016-01-01

    Paracoccidioides spp., a dimorphic pathogenic fungus, is the etiologic agent of paracoccidioidomycosis (PCM). PCM is an endemic disease that affects at least 10 million people in Latin America, causing severe public health problems. The drugs used against pathogenic fungi have various side effects and limited efficacy; therefore, there is an inevitable and urgent medical need for the development of new antifungal drugs. In the present study, we evaluated the transcriptional profile of Paracoccidioides lutzii exposed to argentilactone, a constituent of the essential oil of Hyptis ovalifolia. A total of 1,058 genes were identified, of which 208 were up-regulated and 850 were down-regulated. Cell rescue, defense and virulence, with a total of 26 genes, was a functional category with a large number of genes induced, including heat shock protein 90 (hsp90), cytochrome c peroxidase (ccp), the hemoglobin ligand RBT5 (rbt5) and superoxide dismutase (sod). Quantitative real-time PCR revealed an increase in the expression level of all of those genes. An enzymatic assay showed a significant increase in SOD activity. The reduced growth of Pbhsp90-aRNA, Pbccp-aRNA, Pbsod-aRNA and Pbrbt5-aRNA isolates in the presence of argentilactone indicates the importance of these genes in the response of Paracoccidioides spp. to argentilactone. The response of the P. lutzii cell wall to argentilactone treatment was also evaluated. The results showed that argentilactone caused a decrease in the levels of polymers in the cell wall. These results suggest that argentilactone is a potential candidate for antifungal therapy. PMID:26734764

  12. The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans

    Directory of Open Access Journals (Sweden)

    Barbara Koch

    2017-12-01

    Full Text Available The interactions of mitochondria with the endoplasmic reticulum (ER are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure. In the model yeast Saccharomyces cerevisiae, the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans. There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1Δ/Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1Δ/Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP kinase Cek1 is reduced in the gem1Δ/Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans. We propose that ER-mitochondria interactions and the ER

  13. Extremal states of energy of a double-layered thick-walled tube - application to residually stressed arteries.

    Science.gov (United States)

    Waffenschmidt, Tobias; Menzel, Andreas

    2014-01-01

    Various biological tissues are designed to optimally support external loads for complex geometries and mechanobiological structures. This results in complex microstructures of such materials. The design of, for instance, (healthy) arteries, which are in the focus of this work, is characterised by a residually stressed fibre-reinforced multi-layered composite with highly non-linear elastic response. The complex interaction of material properties with the geometry and residual stress effects enables the optimal support under different blood pressures, respectively blood flow, within the vessel. The fibres reinforcing the arterial wall, as well as residual stresses present in the vessel, strongly influence its overall behaviour and performance. Turn-over and remodelling processes of the collagenous fibres occurring in the respective layers - either resulting from natural growth phenomena or from artificially induced changes in loading condition such as stent deployment - support the optimisation of the multi-layered composite structure of arteries for the particular loading conditions present in the artery. Within this contribution, the overall energetic properties of an artery are discussed by means of the inflation, bending and extension of a double-layered cylindrical tube. Different states of residual stresses and different fibre orientations are considered so that, for instance, representative fibre angles that result in extremal states of the total potential energy can be identified. In view of turn-over and remodelling processes, these orientations are considered to constitute preferred directions of fibre alignment. In summary, the main goal of this work is to calculate optimal material, structural and loading parameters by concepts of energy-minimisation. Several numerical studies show that the obtained values - such as the fibre orientations, the residual axial stretch and the opening angle - are in good agreement with respective physiological parameters

  14. Arrhythmogenic right ventricular dysplasia: Atypical clinical presentation.

    Science.gov (United States)

    Marçalo, José; Menezes Falcão, Luiz

    2017-03-01

    A 67-year-old man was admitted to our hospital after episodes of syncope preceded by malaise and diffuse neck and chest discomfort. No family history of cardiac disease was reported. Laboratory workup was within normal limits, including D-dimers, serum troponin I and arterial blood gases. The electrocardiogram showed sinus rhythm with T-wave inversion in leads V1 to V3. Computed tomography angiography to investigate pulmonary embolism showed no abnormal findings. Transthoracic echocardiography (TTE) displayed massive enlargement of the right ventricle with intact interatrial septum and no pulmonary hypertension. Cardiac magnetic resonance imaging (MRI) confirmed right ventricular (RV) dilatation and revealed marked hypokinesia/akinesia of the lateral wall. Exercise stress testing was negative for ischemia. According to the 2010 Task Force criteria for arrhythmogenic right ventricular dysplasia (ARVD), this patient presented two major criteria (global or regional dysfunction and structural alterations: by MRI, regional RV akinesia or dyskinesia or dyssynchronous RV contraction and RV ejection fraction ≤40%, and repolarization abnormalities: inverted T waves in right precordial leads [V1, V2, and V3]); and one minor criterion (>500 ventricular extrasystoles per 24 hours by Holter), and so a diagnosis of ARVD was made. After electrophysiologic study (EPS) the patient received an implantable cardioverter-defibrillator (ICD). This late clinical presentation of ARVD highlights the importance of TTE screening, possibly complemented by MRI. The associated risk of sudden death was assessed by EPS leading to the implantation of an ICD. Genetic association studies should be offered to the offspring of all ARVD patients. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high efficiency SPECT

    Science.gov (United States)

    Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

    2016-01-01

    Background Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Methods Fifty patients (mean age 69 y) undergoing regadenoson same-day rest (8–11 mCi)/stress (32–42mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started one min after sequential intravenous regadenoson 0.4mg and Tc-99m injection, and was composed of five 2 min supine gated acquisitions followed by two 4 min supine and upright images. Ischemic total perfusion deficit (ITPD) ≥ 5 % was considered as significant ischemia. Results Significantly lower mean EF reserve was obtained in the 5th and 9th min after regadenoson bolus in patients with significant ischemia versus patients without (5th min: −4.2 ± 4.6% vs. 1.3 ± 6.6%, p = 0.006; 9th min: −2.7 ± 4.8% vs. 2.0 ± 6.6%, p = 0.03). Conclusions Negative EF reserve obtained between 5th and 9th min of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of myocardial stunning with Tc-99m HE-SPECT. PMID:27387521

  16. Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT.

    Science.gov (United States)

    Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

    2016-12-01

    Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Fifty patients (mean age 69 years) undergoing regadenoson same-day rest (8-11 mCi)/stress (32-42 mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started 1 minute after sequential intravenous regadenoson .4 mg and Tc-99m injections, and was composed of five 2 minutes supine gated acquisitions followed by two 4 minutes supine and upright images. Ischemic total perfusion deficit (ITPD) ≥5 % was considered as significant ischemia. Significantly lower mean EF reserve was obtained in the 5th and 9th minute after regadenoson bolus in patients with significant ischemia vs patients without (5th minute: -4.2 ± 4.6% vs 1.3 ± 6.6%, P = .006; 9th minute: -2.7 ± 4.8% vs 2.0 ± 6.6%, P = .03). Negative EF reserve obtained between 5th and 9th minutes of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of transient ischemic functional changes with Tc-99m HE-SPECT.

  17. Dietary Saccharomyces cerevisiae Cell Wall Extract Supplementation Alleviates Oxidative Stress and Modulates Serum Amino Acids Profiles in Weaned Piglets

    Directory of Open Access Journals (Sweden)

    Gang Liu

    2017-01-01

    Full Text Available This research aims to evaluate the effects of dietary supplementation with Saccharomyces cerevisiae cell wall extract (SCCWE on growth performance, oxidative stress, intestinal morphology, and serum amino acid concentration in weaned piglets. Utilizing a completely randomized design, 40 healthy piglets weaned at 21 d were grouped into 4 experimental treatments with 10 pigs per treatment group. Treatments consisted of a basal diet (T0, a basal diet with a 0.05% SCCWE (T1, a basal diet with a 0.10% SCCWE (T2, and a basal diet with a 0.15% SCCWE (T3. SCCWE supplementation increased the average daily gain and final body weight compared with T0 (P<0.05. SCCWE in T2 and T3 improved the average daily feed intake and decreased the feed/gain ratio compared with T1 and T2 (P<0.05. SCCWE decreased serum malondialdehyde (MDA and increased activities of catalase (CAT, glutathione peroxidase (GPx, and superoxide dismutase (SOD significantly compared to T0 (P<0.05. SCCWE increased the concentration of Ile compared to T0 (P<0.05. Moreover, the concentrations of Leu, Phe, and Arg were higher in T2 and T3 (P<0.05. These findings indicate beneficial effects of SCCWE supplementation on growth performance, the concentration of some essential amino acids, and alleviation of oxidative stress in weaned piglets.

  18. Osmotic stress adaptation in Lactobacillus casei BL23 leads to structural changes in the cell wall polymer lipoteichoic acid.

    Science.gov (United States)

    Palomino, Maria Mercedes; Allievi, Mariana C; Gründling, Angelika; Sanchez-Rivas, Carmen; Ruzal, Sandra M

    2013-11-01

    The probiotic Gram-positive bacterium Lactobacillus casei BL23 is naturally confronted with salt-stress habitats. It has been previously reported that growth in high-salt medium, containing 0.8 M NaCl, leads to modifications in the cell envelope of this bacterium. In this study, we report that L. casei BL23 has an increased ability to form biofilms and to bind cations in high-salt conditions. This behaviour correlated with modifications of surface properties involving teichoic acids, which are important cell wall components. We also showed that, in these high-salt conditions, L. casei BL23 produces less of the cell wall polymer lipoteichoic acid (LTA), and that this anionic polymer has a shorter mean chain length and a lower level of d-alanyl-substitution. Analysis of the transcript levels of the dltABCD operon, encoding the enzymes required for the incorporation of d-alanine into anionic polymers, showed a 16-fold reduction in mRNA levels, which is consistent with a decrease in d-alanine substitutions on LTA. Furthermore, a 13-fold reduction in the transcript levels was observed for the gene LCABL_09330 coding for a putative LTA synthase. To provide further experimental evidence that LCABL_09330 is a true LTA synthase (LtaS) in L. casei BL23, the enzymic domain was cloned and expressed in E. coli. The purified protein was able to hydrolyse the membrane lipid phosphatidylglycerol as expected for an LTA synthase enzyme, and hence LCABL_09330 was renamed LtaS. The purified enzyme showed Mn(2+)-ion dependent activity, and its activity was modulated by differences in NaCl concentration. The decrease in both ltaS transcript levels and enzyme activity observed in high-salt conditions might influence the length of the LTA backbone chain. A putative function of the modified LTA structure is discussed that is compatible with the growth under salt-stress conditions and with the overall envelope modifications taking place during this stress condition.

  19. Preliminary intraobserver and interobserver variability in wall stress and rupture risk assessment of abdominal aortic aneurysms using a semiautomatic finite element model.

    Science.gov (United States)

    Teutelink, Arno; Cancrinus, Ernst; van de Heuvel, Danyel; Moll, Frans; de Vries, Jean-Paul

    2012-02-01

    We investigated the intraobserver and interobserver variability of using semiautomatic finite element analysis to calculate the von Mises stress and peak wall rupture risk (PWRR) in patients with an abdominal aortic aneurysm (AAA) in longitudinal studies. Four independent observers made 3-dimensional (3D) reconstructions, with minimal manual adjustments, of small AAAs (method was used to calculate von Mises stress and PWRR, which are indicators for wall stress. The differences of each pair of measurements of von Mises stress and PWRR were plotted against their mean and the difference of the mean, according to Bland-Altman analysis. The intraobserver variability had an overall mean percentage difference of 6.86% ± 6.46% for the von Mises stress and 7.70% ± 6.26% for PWRR. The interobserver variability for the four observers showed an overall mean percentage difference of 7.09% ± 6.16% for the von Mises stress and 9.47% ± 8.18% for the PWRR measurement. No significant differences were found (P calculated in this semiautomatic finite element analysis program show good interobserver and intraobserver variability. It is suitable for clinical use to evaluate mechanical aortic wall characteristics and to compare it with other current methods such as maximum aortic diameter measurements. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  20. The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment

    NARCIS (Netherlands)

    Cibis, Merih; Potters, Wouter V.; Gijsen, Frank J.; Marquering, Henk; van Ooij, Pim; VanBavel, Ed; Wentzel, Jolanda J.; Nederveen, Aart J.

    2016-01-01

    Introduction Wall shear stress (WSS) and oscillatory shear index (OSI) are associated with atherosclerotic disease. Both parameters are derived from blood velocities, which can be measured with phase-contrast MRI (PC-MRI). Limitations in spatiotemporal resolution of PC-MRI are known to affect these

  1. Analysis of Peristaltic Motion of a Nanofluid with Wall Shear Stress, Microrotation, and Thermal Radiation Effects

    Directory of Open Access Journals (Sweden)

    C. Dhanapal

    2016-01-01

    Full Text Available This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived. The phenomena of shear stress and trapping have also been discussed. Finally, the influences of various parameters of interest on flow variables have been discussed numerically and explained graphically. Besides, the results obtained in this paper will be helpful to those who are working on the development of various realms like fluid mechanics, the rotation, Brownian motion, thermophoresis, coupling number, micropolar parameter, and the nondimensional geometry parameters.

  2. Transient left ventricular apical ballooning and exercise induced hypertension during treadmill exercise testing: is there a common hypersympathetic mechanism?

    Directory of Open Access Journals (Sweden)

    Oh Jae K

    2008-07-01

    Full Text Available Abstract Objective To describe two cases of Takotsubo like myocardial contractile pattern during exercise stress test secondary to hypertensive response. Background Treadmill exercise testing is known to cause sympathetic stimulation, leading to increased levels of catecholamine, resulting in alteration in vascular tone. Hypertensive response during exercise testing can cause abnormal consequences, resulting in false positive results. Cases We present the cases of two patients experiencing apical and basal akinesis during exercise stress echocardiography, in whom normal wall motion response was observed on subsequent pharmacologic stress testing. The first patient developed transient left ventricular (LV apical akinesis during exercise stress echocardiography. Due to high suspicion that this abnormality might be secondary to hypertensive response, pharmacologic stress testing was performed after three days, which was completely normal and showed no such wall motion abnormality. Qualitative assessment of myocardial perfusion using contrast was also performed, which showed good myocardial blood flow, indicating low probability for significant obstructive coronary artery disease. The second patient developed LV basal akinesis as a result of hypertensive response during exercise testing. Coronary angiogram was not performed in either patient due to low suspicion for coronary artery disease, and subsequently negative stress studies. Results Transient stress induced cardiomyopathy can develop secondary to hypertensive response during exercise stress testing. Conclusion These cases provide supporting evidence to the hyper-sympathetic theory of left ventricular ballooning syndrome.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. Left ventricular function in response to dipyridamole stress: head-to-head comparison between {sup 82}Rubidium PET and {sup 99m}Tc-sestamibi SPECT ECG-gated myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Giorgi, Maria Clementina; Meneghetti, Jose Claudio; Soares, Jose; Izaki, Marisa; Falcao, Andrea; Imada, Rodrigo; Chalela, William; Oliveira, Marco Antonio de; Nomura, Cesar [Department of Radiology and Nuclear Medicine and Molecular Imaging Service - Heart Institute of the University of Sao Paulo Medical School, Sao Paulo (Brazil); Verberne, Hein J. [University of Amsterdam, Department of Nuclear Medicine, Academic Medical Center, P.O. Box 22700, Amsterdam (Netherlands)

    2017-05-15

    Myocardial perfusion imaging (MPI) with {sup 99m}Tc-sestamibi (sestamibi) SPECT and rubidium-82 ({sup 82}Rb) PET both allow for combined assessment of perfusion and left ventricular (LV) function. We sought to compare parameters of LV function obtained with both methods using a single dipyridamole stress dose. A group of 221 consecutive patients (65.2 ± 10.4 years, 52.9% male) underwent consecutive sestamibi and {sup 82}Rb MPI after a single dipyridamole stress dose. Sestamibi and {sup 82}Rb summed rest (SRS), stress (SSS) and difference (SDS) scores, and LV end-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were compared. Bland-Altman analysis showed that with increasing ESV and EDV the difference between the two perfusion tracers increased both at rest and post-stress. The mean difference in EDV and ESV between the two perfusion tracers at rest could both be independently explained by the {sup 82}Rb SDS and the sestamibi SRS. The combined models explained approximately 30% of the variation in these volumes between the two perfusion tracers (R{sup 2} = 0.261, p = 0.005; R{sup 2} = 0.296, p < 0.001, for EDV and ESV respectively). However, the mean difference in LVEF between sestamibi and {sup 82}Rb showed no significant trend post-stress (R{sup 2} = 0.001, p = 0.70) and only a modest linear increase with increasing LVEF values at rest (R{sup 2} = 0.032, p = 0.009). Differences in left ventricular volumes between sestamibi and {sup 82}Rb MPI increase with increasing volumes. However, these differences did only marginally affect LVEF between sestamibi and {sup 82}Rb. In clinical practice these results should be taken into account when comparing functional derived parameters between sestamibi and {sup 82}Rb MPI. (orig.)

  6. Acetylation of cell wall is required for structural integrity of the leaf surface and exerts a global impact on plant stress responses

    Directory of Open Access Journals (Sweden)

    Majse eNafisi

    2015-07-01

    Full Text Available The epidermis on leaves protects plants from pathogen invasion and provides a waterproof barrier. It consists of a layer of cells that is surrounded by thick cell walls, which are partially impregnated by highly hydrophobic cuticular components. We show that the Arabidopsis T-DNA insertion mutants of REDUCED WALL ACETYLATION 2 (rwa2, previously identified as having reduced O-acetylation of both pectins and hemicelluloses, exhibit pleiotrophic phenotype on the leaf surface. The cuticle layer appeared diffused and was significantly thicker and underneath cell wall layer was interspersed with electron-dense deposits. A large number of trichomes were collapsed and surface permeability of the leaves was enhanced in rwa2 as compared to the wild type. A massive reprogramming of the transcriptome was observed in rwa2 as compared to the wild type, including a coordinated up-regulation of genes involved in responses to abiotic stress, particularly detoxification of reactive oxygen species, and defense against microbial pathogens (e.g. lipid transfer proteins, peroxidases. In accordance, peroxidase activities were found to be elevated in rwa2 as compared to the wild type. These results indicate that cell wall acetylation is essential for maintaining the structural integrity of leaf epidermis, and that reduction of cell wall acetylation leads to global stress responses in Arabidopsis.

  7. Double-sling procedure for the surgical management of stress urinary incontinence with concomitant anterior vaginal wall prolapse.

    Science.gov (United States)

    Yonguc, Tarik; Bozkurt, Ibrahim Halil; Sen, Volkan; Aydogdu, Ozgu; Yonguc, Goksin Nilufer; Gunlusoy, Bulent

    2015-10-01

    To assess the safety, efficacy of double-sling procedure (DS) for the surgical management of stress urinary incontinence (SUI) with concomitant anterior wall prolapse (AVWP) and to identify if less synthetic material implantation will decrease the complication rates without decreasing the high cure rates. We reviewed the women who underwent DS in two institutions from January 2009 to December 2013. In DS, there are two transobturator tapes inserted from two different routes for the surgical management of SUI with concomitant AVWP. POP-Q was used for anatomical evaluation of prolapse. SUI was assessed by cough stress test and ICIQ-SF questionnaire. We accepted that the patient was satisfied if the visual analog scale score was ≥80. The severity of urinary incontinence was classified by ICIQ-SF. The women were evaluated at the 3 and 12 months and annually. A total of 74 women met the requirements for inclusion and had sufficient records for analysis. The mean follow-up period was 35.4 months (range 12-60). Operative time was 33.2 ± 6.2. The objective cure and subjective success rates of SUI were 87.8 and 93.2 %, respectively. The satisfaction from the surgery was also high with 86.5 % rate. The anatomical success in our series was rather high with 96 % rate. Our overall complication rate was 12.2 %. Mesh extrusion rate was 0 %. Double-sling procedure is feasible, efficient, and safe. Reducing the mesh size did not have a detrimental effect on the outcomes of SUI treatment and simultaneous AVWP repair.

  8. Ventricular arrhythmias and left ventricular hypertrophy in hypertrophic cardiomyopathy.

    Science.gov (United States)

    Piva e Mattos, Beatriz; Torres, Marco Antonio Rodrigues; Freitas, Valéria Centeno de; Scolari, Fernando Luís; Loreto, Melina Silva de

    2013-05-01

    In hypertrophic cardiomyopathy (HCM), the degree of left ventricular hypertrophy (LVH) could influence the development of ventricular arrhythmias. In HCM, analyze the association between the occurrence of ventricular arrhythmias determined by Holter electrocardiogram (ECG-Holter) and the degree of LVH determined by maximum wall thickness (MWT) in echocardiography and body mass index (BMI). Fifty-four consecutive patients with HCM underwent 24-hour ECG-Holter and echocardiography for assessment of level of LVH through MWT and BMI. Two levels were established for the occurrence of Ventricular Arrhythmias: I - alone or paired extrasystoles and II - Non- Sustained Ventricular Tachycardia (NSVT). In 13 patients (24%) with NSVT (level II), there was a higher frequency of MWT of the left ventricle (LV) > 21 mm (n = 10, 77%, 25 ± 4 mm) and LLLV = 144 g/m² (n = 10, 77%, 200 ± 30 g/m²), in comparison with those presenting with extrasystole arrhythmias (level I) (n = 41, 76%), in which these measures were identified in, respectively, 37 % (n= 15, 23 ± 1 mm), p = 0.023, and 39% (n = 16, 192 ± 53 g / m²) of the cases (p = 0.026). The cut-off values mentioned were determined by the ROC curve with a confidence interval of 95%. NSVT was more common in patients with MWTLV > 21 mm and LLLV > 144 g/m² (8 of 13, 62%) than in those with (4 of 13, 31%) or without (1 of 13; 8%) echocardiographic variables above cut-off values (p = 0.04). In HCM, occurrence of ventricular arrhythmias by Holter was associated with the degree of LVH assessed by echocardiography through MWT and BMI.

  9. The role of the carotid sinus in the reduction of arterial wall stresses due to head movements--potential implications for cervical artery dissection.

    Science.gov (United States)

    Callaghan, F M; Soellinger, M; Baumgartner, R W; Poulikakos, D; Boesiger, P; Kurtcuoglu, V

    2009-04-16

    Spontaneous dissection of the cervical internal carotid artery (sICAD) is a major cause of stroke in young adults. A tear in the inner part of the vessel wall triggers sICAD as it allows the blood to enter the wall and develop a transmural hematoma. The etiology of the tear is unknown but many patients with sICAD report an initiating trivial trauma. We thus hypothesised that the site of the tear might correspond with the location of maximal stress in the carotid wall. Carotid artery geometries segmented from magnetic resonance images of a healthy subject at different static head positions were used to define a path of motion and deformation of the right cervical internal carotid artery (ICA). Maximum head rotation to the left and rotation to the left combined with hyperextension of the neck were investigated using a structural finite element model. A role of the carotid sinus as a geometrically compliant feature accommodating extension of the artery is shown. At the extreme range of the movements, the geometrical compliance of the carotid sinus is limited and significant stress concentrations appear just distal to the sinus with peak stresses at the internal wall on the posterior side of the vessel following maximum head rotation and on the anteromedial portion of the vessel wall following rotation and hyperextension. Clinically, the location of sICAD initiation is 10-30 mm distal to the origin of the cervical ICA, which corresponds with the peak stress locations observed in the model, thus supporting trivial trauma from natural head movements as a possible initiating factor in sICAD.

  10. Notch1 and 4 Signaling Responds to an Increasing Vascular Wall Shear Stress in a Rat Model of Arteriovenous Malformations

    Directory of Open Access Journals (Sweden)

    Jian Tu

    2014-01-01

    Full Text Available Notch signaling is suggested to promote the development and maintenance of cerebral arteriovenous malformations (AVMs, and an increasing wall shear stress (WSS contributes to AVM rupture. Little is known about whether WSS impacts Notch signaling, which is important for understanding the angiogenesis of AVMs. WSS was measured in arteriovenous fistulas (AVF surgically created in 96 rats at different time points over a period of 84 days. The expression of Notch receptors 1 and 4 and their ligands, Delta1 and 4, Jagged1, and Notch downstream gene target Hes1 was quantified in “nidus” vessels. The interaction events between Notch receptors and their ligands were quantified using proximity ligation assay. There was a positive correlation between WSS and time (r=0.97; P<0.001. The expression of Notch receptors and their ligands was upregulated following AVF formation. There was a positive correlation between time and the number of interactions between Notch receptors and their ligands aftre AVF formation (r=0.62, P<0.05 and a positive correlation between WSS and the number of interactions between Notch receptors and their ligands (r=0.87, P<0.005. In conclusion, an increasing WSS may contribute to the angiogenesis of AVMs by activation of Notch signaling.

  11. Time-resolved particle image velocimetry measurements with wall shear stress and uncertainty quantification for the FDA benchmark nozzle model

    CERN Document Server

    Raben, Jaime S; Robinson, Ronald; Malinauskas, Richard; Vlachos, Pavlos P

    2014-01-01

    We present validation of benchmark experimental data for computational fluid dynamics (CFD) analyses of medical devices using advanced Particle Image Velocimetry (PIV) processing and post-processing techniques. This work is an extension of a previous FDA-sponsored multi-laboratory study, which used a medical device mimicking geometry referred to as the FDA benchmark nozzle model. Time-resolved PIV analysis was performed in five overlapping regions of the model for Reynolds numbers in the nozzle throat of 500, 2,000, 5,000, and 8,000. Images included a two-fold increase in spatial resolution in comparison to the previous study. Data was processed using ensemble correlation, dynamic range enhancement, and phase correlations to increase signal-to-noise ratios and measurement accuracy, and to resolve flow regions with large velocity ranges and gradients, which is typical of many blood-contacting medical devices. Parameters relevant to device safety, including shear stress at the wall and in bulk flow, were comput...

  12. Increased reactive oxygen species, metabolic maladaptation, and autophagy contribute to pulmonary arterial hypertension-induced ventricular hypertrophy and diastolic heart failure.

    Science.gov (United States)

    Rawat, Dhawjbahadur K; Alzoubi, Abdallah; Gupte, Rakhee; Chettimada, Sukrutha; Watanabe, Makino; Kahn, Andrea G; Okada, Takao; McMurtry, Ivan F; Gupte, Sachin A

    2014-12-01

    Pulmonary arterial hypertension (PAH) is a debilitating and deadly disease with no known cure. Heart failure is a major comorbidity and a common cause of the premature death of patients with PAH. Increased asymmetrical right ventricular hypertrophy and septal wall thickening compress the left ventricular cavity and elicit diastolic heart failure. In this study, we used the Sugen5416/hypoxia/normoxia-induced PAH rat to determine whether altered pyridine nucleotide signaling in the failing heart contributes to 1) increased oxidative stress, 2) changes in metabolic phenotype, 3) autophagy, and 4) the PAH-induced failure. We found that increased reactive oxygen species, metabolic maladaptation, and autophagy contributed to the pathogenesis of right ventricular remodeling and hypertrophy that lead to left ventricular diastolic dysfunction. In addition, arterial elastance increased in PAH rats. Glucose-6-phosphate dehydrogenase is a major source of pyridine molecule (nicotinamide adenine dinucleotide phosphate), which is a substrate for nicotinamide adenine dinucleotide phosphate oxidases in the heart. Dehydroepiandrosterone, a 17-ketosteroid that reduces pulmonary hypertension and right ventricular hypertrophy, inhibited glucose-6-phosphate dehydrogenase, decreased oxidative stress, increased glucose oxidation and acetyl-coA, and reduced autophagy in the hearts of PAH rats. It also decreased arterial stiffness and improved left ventricular diastolic function. These findings demonstrate that pyridine nucleotide signaling, at least partly, mediates PAH-induced diastolic heart failure, and that reduction of glucose-6-phosphate dehydrogenase-derived nicotinamide adenine dinucleotide phosphate is beneficial to improve left ventricle diastolic function. © 2014 American Heart Association, Inc.

  13. Cine MR imaging after myocardial infarction--assessment and follow-up of regional and global left ventricular function.

    Science.gov (United States)

    Sandstede, J J; Lipke, C; Kenn, W; Beer, M; Pabst, T; Hahn, D

    1999-12-01

    Myocardial infarction often leads to regional wall motion defects and in case of large defects to remodeling of the left ventricle. With this study, changes in regional and global myocardial function of 12 patients 3 weeks after myocardial infarction and after revascularization therapy were determined using MRI. Cine MRI was performed at study entry at rest and during low-dose dobutamine stimulation. All patients were re-examined at rest 3 and 6 months after the revascularization, including analysis of wall thickening and of left ventricular end-diastolic volume index (LVEDVI), end-systolic volume index (LVESVI), ejection fraction (LVEF), and mass index. After revascularization. 6 patients with stress-induced improvement of regional wall thickening recovered, 4 patients without improvement did not, but 2 patients without stress-induced improvement of wall thickening also recovered. Concerning global cardiac function, patients with mainly improved regional wall motion also showed a lower LVESVI and a higher LVEF than patients without improvement of regional contractility 6 months after revascularization in comparison to study entry. In conclusion, improvement of global myocardial function after revascularization is higher in patients with improved contractility in the infarcted region. The extent of the response of regions with wall motion defects to dobutamine stress correlates with the actual improvement after revascularization, and, therefore, dobutamine stress MRI may be helpful in selecting patients that will have a higher benefit from a revascularization therapy.

  14. Influence of a laminar steady-state fluid-imposed wall shear stress on the binding, internalization, and degradation of low-density lipoproteins by cultured arterial endothelium.

    Science.gov (United States)

    Sprague, E A; Steinbach, B L; Nerem, R M; Schwartz, C J

    1987-09-01

    Fluid mechanical steady-state laminar wall shear stresses of 30 dyne/cm2 (high stress) and less than 1 dyne/cm2 (low stress) have been applied for varying times to confluent cultures of bovine aortic endothelial cells (BAECs) by means of two parallel plate channel flow chambers in series. BAEC cultures not exposed to shear or flow (no stress) were also studied. A shear stress of 30 dyne/cm2 resulted in cellular elongation and alignment, changes that were largely complete by 24 hr. In experiments in which BAECs were incubated with 125I-labeled low-density lipoprotein for 2 or 24 hr in the presence of shear stress levels, 125I-LDL internalization at 24 hr was increased (p less than .05) in response to high-stress conditions. This increased uptake of 125I-LDL was observed in BAECs prealigned for 24 hr under high stress and in BAECs undergoing alignment in the presence of circulating 125I-LDL. BAECs were also exposed to shear stress for 24 hr in the presence of a lipoprotein-deficient circulating medium to maximize LDL receptor expression. Receptor-mediated 125I-LDL internalization and degradation measured immediately after shear stress were both significantly enhanced (p less than .01) in BAECs exposed to high stress. Furthermore, 125I-LDL binding studies at 4 degrees C revealed a significant increase (p less than .01) in specific 125I-LDL binding to BAECs exposed to high stress relative to those exposed to low or no stress. Nonspecific 125I-LDL endocytosis was not influenced by shear stress levels.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Effects of aortic root motion on wall stress in the Marfan aorta before and after personalised aortic root support (PEARS) surgery.

    Science.gov (United States)

    Singh, S D; Xu, X Y; Pepper, J R; Izgi, C; Treasure, T; Mohiaddin, R H

    2016-07-05

    Aortic root motion was previously identified as a risk factor for aortic dissection due to increased longitudinal stresses in the ascending aorta. The aim of this study was to investigate the effects of aortic root motion on wall stress and strain in the ascending aorta and evaluate changes before and after implantation of personalised external aortic root support (PEARS). Finite element (FE) models of the aortic root and thoracic aorta were developed using patient-specific geometries reconstructed from pre- and post-PEARS cardiovascular magnetic resonance (CMR) images in three Marfan patients. The wall and PEARS materials were assumed to be isotropic, incompressible and linearly elastic. A static load on the inner wall corresponding to the patients' pulse pressure was applied. Cardiovascular MR cine images were used to quantify aortic root motion, which was imposed at the aortic root boundary of the FE model, with zero-displacement constraints at the distal ends of the aortic branches and descending aorta. Measurements of the systolic downward motion of the aortic root revealed a significant reduction in the axial displacement in all three patients post-PEARS compared with its pre-PEARS counterparts. Higher longitudinal stresses were observed in the ascending aorta when compared with models without the root motion. Implantation of PEARS reduced the longitudinal stresses in the ascending aorta by up to 52%. In contrast, the circumferential stresses at the interface between the supported and unsupported aorta were increase by up to 82%. However, all peak stresses were less than half the known yield stress for the dilated thoracic aorta. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Lie point symmetries for a magneto couple stress fluid in a porous channel with expanding or contracting walls and slip boundary condition

    Directory of Open Access Journals (Sweden)

    Rabea El Shennawy Abo Elkhair

    2016-10-01

    Full Text Available In this paper, an incompressible couple stress fluid flow with magnetic field in a porous channel with expanding or contracting walls and slip boundary condition is considered. Lie group analysis and group invariant solutions are obtained, the governing equations are reduced to nonlinear ordinary differential equations. The resulting equations are solved analytically, also this equations are solved by using Adomian method. The graphs for the axial and the normal velocity components and the pressure distribution for different values of the physical and geometric parameters are plotted and discussed. Finally, the comparison between the analytic and Adomian methods is discussed. It is found that for no-slip case ϕ=0 the fluid adheres to the walls and axial velocity is maximum at the center of the channel, also by increasing the slip parameter the velocity at the channel walls increases. However, it decreases at center of the channel by increasing slip parameter.

  17. Arrhythmogenic right ventricular dysplasia

    OpenAIRE

    Bockeria O.L.; Lе T.G.

    2015-01-01

    Arrhythmogenic right ventricular dysplasia is a hereditary cardiomyopathy characterized by structural and functional disorders in the right ventricle, which results in ventricular arrhythmias. Arrhythmogenic right ventricular dysplasia is one of the important causes of sudden cardiac death in young people and athletes. Structural disorders in arrhythmogenic right ventricular dysplasia are associated with fibrosis and fatty infiltration of the right ventricular myocardium. These changes lead t...

  18. Left Ventricular Myocardial Function in Children With Pulmonary Hypertension: Relation to Right Ventricular Performance and Hemodynamics.

    Science.gov (United States)

    Burkett, Dale A; Slorach, Cameron; Patel, Sonali S; Redington, Andrew N; Ivy, D Dunbar; Mertens, Luc; Younoszai, Adel K; Friedberg, Mark K

    2015-08-01

    Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH. At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; Pright ventricular free-wall LS (r=0.64; Pright ventricular strain, and functional PH measures. © 2015 American Heart Association, Inc.

  19. Positional Right Ventricular Obstruction in Pectus Excavatum.

    Science.gov (United States)

    Underwood, Katherine; Vorsanger, Matthew; Saric, Muhamed; Skolnick, Adam H

    2017-04-15

    Pectus excavatum is one of the most common congenital chest wall deformities. The degree of sternal depression, which may result in compression of the right heart by the chest wall, is variable. While typically asymptomatic, there are various symptoms that can result from severe pectus excavatum. We report on a patient with severe pectus excavatum leading to dynamic obstruction of the right ventricular outflow tract in the seated position. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Right Ventricular Perfusion: Physiology and Clinical Implications.

    Science.gov (United States)

    Crystal, George J; Pagel, Paul S

    2018-01-01

    Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure-flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins. These differences promote the maintenance of right ventricular oxygen supply-demand balance and provide relative resistance to ischemia-induced contractile dysfunction and infarction, but they may be compromised during acute or chronic increases in right ventricle afterload resulting from pulmonary arterial hypertension. Contractile function of the thin-walled right ventricle is exquisitely sensitive to afterload. Acute increases in pulmonary arterial pressure reduce right ventricular stroke volume and, if sufficiently large and prolonged, result in right ventricular failure. Right ventricular ischemia plays a prominent role in these effects. The risk of right ventricular ischemia is also heightened during chronic elevations in right ventricular afterload because microvascular growth fails to match myocyte hypertrophy and because microvascular

  1. Submitral Left Ventricular Aneurysm Associated with Thrombus

    African Journals Online (AJOL)

    2018-01-01

    Jan 1, 2018 ... ventricular wall adjacent to the posterior leaflet of the mitral valve is the commonly reportedpresentation (3).Other less frequently associated causes are: Takayasu's arteritis, rheumatic fever, tuberculosis, infective endocarditis, ischemic heart disease, and vascular tumors. There are also other reported ...

  2. Histone acetylation associated up-regulation of the cell wall related genes is involved in salt stress induced maize root swelling.

    Science.gov (United States)

    Li, Hui; Yan, Shihan; Zhao, Lin; Tan, Junjun; Zhang, Qi; Gao, Fei; Wang, Pu; Hou, Haoli; Li, Lijia

    2014-04-23

    Salt stress usually causes crop growth inhibition and yield decrease. Epigenetic regulation is involved in plant responses to environmental stimuli. The epigenetic regulation of the cell wall related genes associated with the salt-induced cellular response is still little known. This study aimed to analyze cell morphological alterations in maize roots as a consequence of excess salinity in relation to the transcriptional and epigenetic regulation of the cell wall related protein genes. In this study, maize seedling roots got shorter and displayed swelling after exposure to 200 mM NaCl for 48 h and 96 h. Cytological observation showed that the growth inhibition of maize roots was due to the reduction in meristematic zone cell division activity and elongation zone cell production. The enlargement of the stele tissue and cortex cells contributed to root swelling in the elongation zone. The cell wall is thought to be the major control point for cell enlargement. Cell wall related proteins include xyloglucan endotransglucosylase (XET), expansins (EXP), and the plasma membrane proton pump (MHA). RT-PCR results displayed an up-regulation of cell wall related ZmEXPA1, ZmEXPA3, ZmEXPA5, ZmEXPB1, ZmEXPB2 and ZmXET1 genes and the down-regulation of cell wall related ZmEXPB4 and ZmMHA genes as the duration of exposure was increased. Histone acetylation is regulated by HATs, which are often correlated with gene activation. The expression of histone acetyltransferase genes ZmHATB and ZmGCN5 was increased after 200 mM NaCl treatment, accompanied by an increase in the global acetylation levels of histones H3K9 and H4K5. ChIP experiment showed that the up-regulation of the ZmEXPB2 and ZmXET1 genes was associated with the elevated H3K9 acetylation levels on the promoter regions and coding regions of these two genes. These data suggested that the up-regulation of some cell wall related genes mediated cell enlargement to possibly mitigate the salinity-induced ionic toxicity, and

  3. Cantrell's Syndrome with left ventricular diverticulum: a case report.

    Science.gov (United States)

    Manieri, S; Adurno, G; Iorio, F; Tomasco, B; Vairo, U

    2013-02-01

    Congenital left ventricular diverticulum is a rare condition. When found, it is usually accompanied by other intracardiac malformations, so that again further examination is indicated. Furthermore, it is usually associated with thoracoabdominal wall defect, as seen in the spectrum of Cantrell's pentalogy, a congenital anomaly consisting of a lower sternal defect, diastasis recti, pericardial defect, anterior diaphragmatic hernia and cardiac malformation. This paper reports a case of Cantrell's Syndrome with left ventricular diverticulum. Successful total correction of ventricular diverticulum, ventricular defects and diastasi recti, was performed at two years of age. The clinical features, ambryology and surgical management of these defects are discussed.

  4. Transaortic closure of residual intramural ventricular septal defect.

    Science.gov (United States)

    Belli, E; Houyel, L; Serraf, A; Lacour-Gayet, F; Petit, J; Planché, C

    2000-05-01

    Residual intramural ventricular septal defect is an unusual cause of left-to-right shunt after biventricular repair of conotruncal anomalies. It results from the insertion of the patch within the trabeculated right ventricular free wall related to the ventriculoinfundibular fold creating a communication through the intertrabeculated spaces to the right ventricular cavity. This complication often leads to unsuccessful reoperations unless the exact mechanism of the shunt has been identified. Five patients presented with residual intramural ventricular septal defects. Three had double outlet right ventricle, one pulmonary atresia with ventricular septal defect, and one tetralogy of Fallot. One patient was unsuccessfully reoperated on for closure of the residual ventricular septal defect through the right ventricular approach. The surgical treatment, which consisted of patch closure of the residual intramural ventricular septal defect through aortotomy, was successful in 3 patients. In the 2 remaining patients the hemodynamically insignificant residual intramural ventricular septal defect remained untouched. No mortality or morbidity occurred. Residual intramural ventricular septal defect should be suspected in presence of a residual ventricular septal defect after biventricular repair of conotruncal anomalies. It is not accessible through either atriotomy or right ventriculotomy. The transaortic approach allows an easy treatment of this rare complication.

  5. [Diagnosis and treatment of arrhythmogenic right ventricular cardiomyopathy in children].

    Science.gov (United States)

    Wang, Shu-Shui; Zhang, Zhi-Wei; Xu, Yan-Mei; Jiang, Qiu-Ping; Li, Hong; Qian, Ming-Yang; Li, Yu-Fen

    2010-03-01

    To summarize the experience in diagnosis and treatment of arrhythmogenic right ventricular cardiomyopathy (ARVC) in children. A total of 14 children (7 females and 7 males) with ARVC were involved. The cases underwent electrocardiography, echocardiography, cardiac CT or MRI examinations. All cases were treated with sotalol or amiodarone in combination with propranolol. In 2 cases with drug-refractory ventricular extrasystoles, catheter ablation treatment was performed. In 6 cases with obvious impaired ventricular function, additional pharmacological therapy including vasodilators, diuretics, and digitalis were given. Ventricular extrasystoles occurred in all 14 cases and ventricular tachycardia in 8 cases. Ten cases showed Epsilon wave on electrocardiography. All 14 cases had enlarged right ventricle and reduced right ventricular ejection fraction. CT or MRI examination showed right ventricular dilatation and a thinned wall of right ventricle in 10 cases. Ventricular extrasystoles or tachycardia disappeared in 7 cases and was reduced in 4 cases after treatment. The two children receiving catheter ablation treatment did not present ventricular extrasystoles or tachycardia in a 3-month follow-up. The heart function was improved in the 6 children with obvious impaired ventricular function after pharmacological therapy. The clinical manifestations are diverse in children with ARVC. A definite diagnosis of ARVC should be based on a combination of electrocardiography and echocardiography examinations. Pharmacological therapy is effective partially. Catheter ablation treatment appears to be a promising option in patients with drug-refractory ventricular extrasystoles.

  6. Altered ventricular stretch contributes to initiation of cardiac memory.

    Science.gov (United States)

    Sosunov, Eugene A; Anyukhovsky, Evgeny P; Rosen, Michael R

    2008-01-01

    Cardiac memory is a change in T-wave morphology induced by ventricular pacing or arrhythmias that persist after resumption of normal AV conduction. Changing the pacemaker site from atrium to ventricle alters ventricular activation and the mechanical pattern of ventricular contraction. Either or both alterations affect T-wave configuration. The purpose of this study was to study the role of altered contractile patterns on initiation of cardiac memory. Isolated rabbit hearts were immersed in Tyrode's solution (37 degrees C) and aortically perfused at a constant pressure of 70 mmHg. Three orthogonal quasi-ECG leads were recorded via six Ag-AgCl electrodes located on the walls of the bath. Hearts were paced at a constant cycle length from either the right atrial appendage or left ventricle lateral wall. The pulmonary artery was sealed, and both ventricles contracted isovolumetrically. Cardiac memory was quantified as T-wave vector displacement expressed as distance between T-wave vector peaks during atrial pacing before and after ventricular pacing. Five minutes of ventricular pacing induced significant T-wave vector displacement that returned to control in 5 to 10 minutes. No significant changes in intraventricular pressure occurred during and after ventricular pacing. Interventions that decreased ventricular load (shunting both ventricles to the bath) or contractility (excitation-contraction uncoupler blebbistatin) significantly decreased developed pressure and eliminated T-wave vector displacement. Neither intervention affected ventricular activation during ventricular pacing. Locally applied left ventricular epicardial stretch induced T-wave vector displacement similar to that induced by ventricular pacing. Altered ventricular activation during ventricular pacing initiates cardiac memory via induction of altered contractile patterns and altered stretch.

  7. Flow induced by ependymal cilia dominates near-wall cerebrospinal fluid dynamics in the lateral ventricles

    Science.gov (United States)

    Siyahhan, Bercan; Knobloch, Verena; de Zélicourt, Diane; Asgari, Mahdi; Schmid Daners, Marianne; Poulikakos, Dimos; Kurtcuoglu, Vartan

    2014-01-01

    While there is growing experimental evidence that cerebrospinal fluid (CSF) flow induced by the beating of ependymal cilia is an important factor for neuronal guidance, the respective contribution of vascular pulsation-driven macroscale oscillatory CSF flow remains unclear. This work uses computational fluid dynamics to elucidate the interplay between macroscale and cilia-induced CSF flows and their relative impact on near-wall dynamics. Physiological macroscale CSF dynamics are simulated in the ventricular space using subject-specific anatomy, wall motion and choroid plexus pulsations derived from magnetic resonance imaging. Near-wall flow is quantified in two subdomains selected from the right lateral ventricle, for which dynamic boundary conditions are extracted from the macroscale simulations. When cilia are neglected, CSF pulsation leads to periodic flow reversals along the ventricular surface, resulting in close to zero time-averaged force on the ventricle wall. The cilia promote more aligned wall shear stresses that are on average two orders of magnitude larger compared with those produced by macroscopic pulsatile flow. These findings indicate that CSF flow-mediated neuronal guidance is likely to be dominated by the action of the ependymal cilia in the lateral ventricles, whereas CSF dynamics in the centre regions of the ventricles is driven predominantly by wall motion and choroid plexus pulsation. PMID:24621815

  8. Experimental Study of Pressure Drop and Wall Shear Stress Characteristics of γ /Al2O3-Water Nanofluid in a Circular pipe under Turbulent flow induced vibration.

    Directory of Open Access Journals (Sweden)

    Adil Abbas AL-Moosawy

    2016-09-01

    Full Text Available Experimental study of γ /Al2O3 with mean diameter of less than 50 nm was dispersed in the distilled water that flows through a pipe consist of five sections as work station ,four sections made of carbon steel metal and one sections made of Pyrex glass pipe, with five nanoparticles volume concentrations of 0%,0.1%,0.2%,0.3%,and 0.4% with seven different volume flow rates 100, 200 , 300, 400, 500, 600 ,and 700ℓ/min were investigated to calculated pressure distribution for the cases without rubber ,with 3mm rubber and with 6mm rubber used to support the pipe. Reynolds number was between 20000 and 130000. Frequency value through pipe was measured for all stations of pipe for all cases. The results show that the pressure drop and wall shear stress of the nanofluid increase by increasing the nanoparticles volume concentrations or Reynolds number, the values of frequency through the pipe increase continuously when wall shear stress increases and the ratio of increment increases as nanofluid concentrations increase. Increasing of vibration frequency lead to increasing the friction factor between the pipe and the wall and thus increasing in pressure drop. Several equations between the wall shear stress and frequency for all volume concentration and for three cases without rubber, with rubber has 3mm thickness ,and with rubber has 6mm thickness. Finally, the results led to that γ /Al2O3 could function as a good and alternative conventional working fluid in heat transfer applications. A good agreement is seen between the experimental and those available in the literature

  9. Impact of wall shear stress and ligand avidity on binding of anti-CD146-coated nanoparticles to murine tumor endothelium under flow

    Science.gov (United States)

    Ryschich, Eduard

    2015-01-01

    The endothelial phenotype of tumor blood vessels differs from the liver and forms an important base for endothelium-specific targeting by antibody-coated nanoparticles. Although differences of shear stress and ligand avidity can modulate the nanoparticle binding to endothelium, these mechanisms are still poorly studied. This study analyzed the binding of antibody-coated nanoparticles to tumor and liver endothelium under controlled flow conditions and verified this binding in tumor models in vivo. Binding of anti-CD146-coated nanoparticles, but not of antibody was significantly reduced under increased wall shear stress and the degree of nanoparticle binding correlated with the avidity of the coating. The intravascular wall shear stress favors nanoparticle binding at the site of higher avidity of endothelial epitope which additionally promotes the selectivity to tumor endothelium. After intravenous application in vivo, pegylated self-coated nanoparticles showed specific binding to tumor endothelium, whereas the nanoparticle binding to the liver endothelium was very low. This study provides a rationale that selective binding of mAb-coated nanoparticles to tumor endothelium is achieved by two factors: higher expression of endothelial epitope and higher nanoparticle shearing from liver endothelium. The combination of endothelial marker targeting and the use of shear stress-controlled nanoparticle capture can be used for selective intratumoral drug delivery. PMID:26503468

  10. Cdc48 and cofactors Npl4-Ufd1 are important for G1 progression during heat stress by maintaining cell wall integrity in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Meng-Ti Hsieh

    Full Text Available The ubiquitin-selective chaperone Cdc48, a member of the AAA (ATPase Associated with various cellular Activities ATPase superfamily, is involved in many processes, including endoplasmic reticulum-associated degradation (ERAD, ubiquitin- and proteasome-mediated protein degradation, and mitosis. Although Cdc48 was originally isolated as a cell cycle mutant in the budding yeast Saccharomyces cerevisiae, its cell cycle functions have not been well appreciated. We found that temperature-sensitive cdc48-3 mutant is largely arrested at mitosis at 37°C, whereas the mutant is also delayed in G1 progression at 38.5°C. Reporter assays show that the promoter activity of G1 cyclin CLN1, but not CLN2, is reduced in cdc48-3 at 38.5°C. The cofactor npl4-1 and ufd1-2 mutants also exhibit G1 delay and reduced CLN1 promoter activity at 38.5°C, suggesting that Npl4-Ufd1 complex mediates the function of Cdc48 at G1. The G1 delay of cdc48-3 at 38.5°C is a consequence of cell wall defect that over-activates Mpk1, a MAPK family member important for cell wall integrity in response to stress conditions including heat shock. cdc48-3 is hypersensitive to cell wall perturbing agents and is synthetic-sick with mutations in the cell wall integrity signaling pathway. Our results suggest that the cell wall defect in cdc48-3 is exacerbated by heat shock, which sustains Mpk1 activity to block G1 progression. Thus, Cdc48-Npl4-Ufd1 is important for the maintenance of cell wall integrity in order for normal cell growth and division.

  11. Improving risk assessment for post-surgical low cardiac output syndrome in patients without severely reduced ejection fraction undergoing open aortic valve replacement. The role of global longitudinal strain and right ventricular free wall strain

    NARCIS (Netherlands)

    Balderas-Munoz, K.; Rodriguez-Zanella, H.; Fritche-Salazar, J. F.; Avila-Vanzzini, N.; Juarez Orozco, L. E.; Arias-Godinez, J. A.; Calvillo-Arguelles, O.; Rivera-Peralta, S.; Sauza-Sosa, J. C.; Ruiz-Esparza, M. E.; Bucio-Reta, E.; Rmero, A.; Espinola-Zavaleta, N.; Dominguez-Mendez, B.; Gaxiola-Macias, M.; Martinez-Rios, M. A.

    2017-01-01

    Low cardiac output syndrome (LCOS) after surgical aortic valve replacement (SAVR) is related to increased mortality and treatment related costs. We aimed to evaluate whether echocardiography-derived left ventricular global longitudinal strain (LV-GLS) relates to the occurrence of postoperative LCOS

  12. Guided waves in pre-stressed hyperelastic plates and tubes: Application to the ultrasound elastography of thin-walled soft materials

    Science.gov (United States)

    Li, Guo-Yang; He, Qiong; Mangan, Robert; Xu, Guoqiang; Mo, Chi; Luo, Jianwen; Destrade, Michel; Cao, Yanping

    2017-05-01

    In vivo measurement of the mechanical properties of thin-walled soft tissues (e.g., mitral valve, artery and bladder) and in situ mechanical characterization of thin-walled artificial soft biomaterials in service are of great challenge and difficult to address via commonly used testing methods. Here we investigate the properties of guided waves generated by focused acoustic radiation force in immersed pre-stressed plates and tubes, and show that they can address this challenge. To this end, we carry out both (i) a theoretical analysis based on incremental wave motion in finite deformation theory and (ii) finite element simulations. Our analysis leads to a novel method based on the ultrasound elastography to image the elastic properties of pre-stressed thin-walled soft tissues and artificial soft materials in a non-destructive and non-invasive manner. To validate the theoretical and numerical solutions and demonstrate the usefulness of the corresponding method in practical measurements, we perform (iii) experiments on polyvinyl alcohol cryogel phantoms immersed in water, using the Verasonics V1 System equipped with a L10-5 transducer. Finally, potential clinical applications of the method have been discussed.

  13. Quantification of wall shear stress using a finite-element method in multidimensional phase-contrast MR data of the thoracic aorta.

    Science.gov (United States)

    Sotelo, Julio; Urbina, Jesús; Valverde, Israel; Tejos, Cristian; Irarrázaval, Pablo; Hurtado, Daniel E; Uribe, Sergio

    2015-07-16

    We present a computational method for calculating the distribution of wall shear stress (WSS) in the aorta based on a velocity field obtained from two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) data and a finite-element method. The WSS vector was obtained from a global least-squares stress-projection method. The method was benchmarked against the Womersley model, and the robustness was assessed by changing resolution, noise, and positioning of the vessel wall. To showcase the applicability of the method, we report the axial, circumferential and magnitude of the WSS using in-vivo data from five volunteers. Our results showed that WSS values obtained with our method were in good agreement with those obtained from the Womersley model. The results for the WSS contour means showed a systematic but decreasing bias when the pixel size was reduced. The proposed method proved to be robust to changes in noise level, and an incorrect position of the vessel wall showed large errors when the pixel size was decreased. In volunteers, the results obtained were in good agreement with those found in the literature. In summary, we have proposed a novel image-based computational method for the estimation of WSS on vessel sections with arbitrary cross-section geometry that is robust in the presence of noise and boundary misplacements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Evaluation of optical data gained by ARAMIS-measurement of abdominal wall movements for an anisotropic pattern design of stress-adapted hernia meshes produced by embroidery technology

    Science.gov (United States)

    Breier, A.; Bittrich, L.; Hahn, J.; Spickenheuer, A.

    2017-10-01

    For the sustainable repair of abdominal wall hernia the application of hernia meshes is required. One reason for the relapse of hernia after surgery is seen in an inadequate adaption of the mechanical properties of the mesh to the movements of the abdominal wall. Differences in the stiffness of the mesh and the abdominal tissue cause tension, friction and stress resulting in a deficient tissue response and subsequently in a recurrence of a hernia, preferentially in the marginal area of the mesh. Embroidery technology enables a targeted influence on the mechanical properties of the generated textile structure by a directed thread deposition. Textile parameters like stitch density, alignment and angle can be changed easily and locally in the embroidery pattern to generate a space-resolved mesh with mechanical properties adapted to the requirement of the surrounding tissue. To determine those requirements the movements of the abdominal wall and the resulting distortions need to be known. This study was conducted to gain optical data of the abdominal wall movements by non-invasive ARAMIS-measurement on 39 test persons to estimate direction and value of the major strains.

  15. [Posterior ventricular septal perforation successfully repaired through right ventricular approach].

    Science.gov (United States)

    Takeuchi, Kazuma; Morishige, N; Iwahashi, H; Hayashida, Y; Teshima, H; Ito, N; Tashiro, T

    2006-12-01

    A 65-year-old man underwent a successful repair of a posterior ventricular septal perforation (VSP) 9 days after suffering an acute inferior myocardial infarction. After hospitalization, his hemodynamic condition gradually worsened, in spite of administering intensive medical therapy. Emergent operation was performed on the 4th day after onset. An equine pericardial patch was sutured around the VSP through the right ventricular side of the septum using the double-patch repair method and the right ventricular wall was closed as using the standard extracorporeal perfusion technique. The dimensions of the VSP measured 5 mm in diameter. Transesophageal echocardiography was performed on the 14th postoperative day. Cardiac catheter examination was done on the 18th postoperative day. No residual shunt was recognized and cardiac function was good. He was discharged on the 20th postoperative day. The occurrence of a posterior VSP is comparatively rare, and repair of VSP is difficult to perform during an acute period. Therefore, the operative results of VSP cases remain poor.

  16. CT imaging features and frequency of left ventricular myocardial fat in patients with CT findings of chronic left ventricular myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, H.M.; Litt, H.I. [Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA (United States); Torigian, D.A. [Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA (United States)], E-mail: drew.torigian@uphs.upenn.edu

    2008-03-15

    Aim: To determine the frequency of left ventricular myocardial fat in patients with computed tomography (CT) findings of chronic left ventricular myocardial infarction, and to review the typical CT imaging features. Materials and methods: A retrospective search of the CT and nuclear scintigraphy reports from 1998-2005 for chronic left ventricular myocardial infarction was performed. The study group comprised those cases with available CT examinations revealing findings of chronic left ventricular myocardial infarction. Assessment for the presence of various imaging characteristics of left ventricular myocardial fat was performed in all cases. Results: The frequency of left ventricular myocardial fat in 47 patients with CT evidence of chronic left ventricular myocardial infarction was 51%. Typical CT imaging features include thin linear or curvilinear fat attenuation within left ventricular myocardium, most commonly subendocardial, often associated with left ventricular wall thinning and/or calcification, predominantly in elderly men. Conclusions: Fat in the left ventricular myocardium is a common additional finding in patients with CT findings of chronic left ventricular myocardial infarction. The potential, but as yet unproven, use of this CT imaging finding is that the radiologist may be able to suggest a potential diagnosis of chronic left ventricular myocardial infarction on unenhanced, thick-section, non-gated or non-triggered chest CT imaging where identification of myocardial wall thinning may be difficult.

  17. Method to Determine the Stress-Strain Response of As-Formed Thin-Walled Tubular Structures Using a Flaring Apparatus

    Science.gov (United States)

    Jurendic, S.; Anderson, D.

    2017-09-01

    Finite element simulations are used extensively to refine the forming steps of draw and wall iron (DWI) aluminum bottles; therefore, accurate material data is required Unfortunately, the material properties of the base sheet cannot presently be used for simulation of the later forming stages due to preceding significant deformation (ironing) and thermal treatments. Measuring the stress-strain response using traditional methods (e.g. tensile test) becomes increasingly difficult at later stages of the bottle forming process due to a significant diameter reduction of the bottle neck from successive die-necking stages. Moreover, failure during forming tends to occur in the final deformation stages when the bottle opening is rolled over, creating a brim roll, at which point brim roll splits may occur. Knowledge of the stress-strain response prior to the roll over may lead to improved product design, reduced waste, and an optimized product. Therefore, this work details a flaring apparatus and data analysis method to determine the stress-strain response in the die-necked region of thin-walled aluminum bottles fabricated from AA3104 sheet metal.

  18. The two-component response regulator LiaR regulates cell wall stress responses, pili expression and virulence in group B Streptococcus.

    Science.gov (United States)

    Klinzing, David C; Ishmael, Nadeeza; Dunning Hotopp, Julie C; Tettelin, Hervé; Shields, Kelly R; Madoff, Lawrence C; Puopolo, Karen M

    2013-07-01

    Group B Streptococcus (GBS) remains the leading cause of early onset sepsis among term infants. Evasion of innate immune defences is critical to neonatal GBS disease pathogenesis. Effectors of innate immunity, as well as numerous antibiotics, frequently target the peptidoglycan layer of the Gram-positive bacterial cell wall. The intramembrane-sensing histidine kinase (IM-HK) class of two-component regulatory systems has been identified as important to the Gram-positive response to cell wall stress. We have characterized the GBS homologue of LiaR, the response regulator component of the Lia system, to determine its role in GBS pathogenesis. LiaR is expressed as part of a three-gene operon (liaFSR) with a promoter located upstream of liaF. A LiaR deletion mutant is more susceptible to cell wall-active antibiotics (vancomycin and bacitracin) as well as antimicrobial peptides (polymixin B, colistin, and nisin) compared to isogenic wild-type GBS. LiaR mutant GBS are significantly attenuated in mouse models of both GBS sepsis and pneumonia. Transcriptional profiling with DNA microarray and Northern blot demonstrated that LiaR regulates expression of genes involved in microbial defence against host antimicrobial systems including genes functioning in cell wall synthesis, pili formation and cell membrane modification. We conclude that the LiaFSR system, the first member of the IM-HK regulatory systems to be studied in GBS, is involved in sensing perturbations in the integrity of the cell wall and activates a transcriptional response that is important to the pathogenesis of GBS infection.

  19. [Multiple right ventricular thrombi in arrhythmogenic right ventricular cardiomyopathy - a case report].

    Science.gov (United States)

    Elikowski, Waldemar; Błaszczyk, Edyta; Małek, Małgorzata; Bolewski, Andrzej; Angerer, Dariusz

    2015-05-01

    Typical complications of arrhythmogenic right ventricular cardiomyopathy (ARVC) are heart failure and ventricular arrhythmias which may lead to sudden cardiac death. Intracardiac thrombosis is diagnosed only in 2-4% of patients. The authors present a case of a 50-year-old male admitted to hospital due to symptomatic ventricular tachycardia. Echocardiography and cardiac magnetic resonance showed advanced ARVC with multiple right ventricular thrombi. The biggest one was localized in the inflow tract below the tricuspid valve, whereas the smallest one beneath it, on the inferior wall; the remaining two - in the apex. Chest computed tomography did not confirm pulmonary embolism. Disappearance of thrombi was observed after 4 weeks of anticoagulation. Detection and appropriate treatment of intracardiac thrombi in ARVC may have relevance in prevention of sudden death, not related to arrhythmia, and is of special importance before cardioverterdefibrillator implantation. © 2015 MEDPRESS.

  20. Ventricular dyssynchrony assessed by gated myocardial perfusion SPECT using a geometrical approach: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Veen, Berlinda J. van der; Younis, Imad Al [Leiden University Medical Centre, Department of Nuclear Medicine, Leiden (Netherlands); Ajmone-Marsan, Nina; Bax, Jeroen J. [Leiden University Medical Centre, Department of Cardiology, Leiden (Netherlands); Westenberg, Jos J.M.; Roos, Albert de [Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands); Stokkel, Marcel P.M. [Antoni van Leeuwenhoek Hospital, Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam (Netherlands)

    2012-03-15

    Left ventricular dyssynchrony may predict response to cardiac resynchronization therapy and may well predict adverse cardiac events. Recently, a geometrical approach for dyssynchrony analysis of myocardial perfusion scintigraphy (MPS) was introduced. In this study the feasibility of this geometrical method to detect dyssynchrony was assessed in a population with a normal MPS and in patients with documented ventricular dyssynchrony. For the normal population 80 patients (40 men and 40 women) with normal perfusion (summed stress score {<=}2 and summed rest score {<=}2) and function (left ventricular ejection fraction 55-80%) on MPS were selected; 24 heart failure patients with proven dyssynchrony on MRI were selected for comparison. All patients underwent a 2-day stress/rest MPS protocol. Perfusion, function and dyssynchrony parameters were obtained by the Corridor4DM software package (Version 6.1). For the normal population time to peak motion was 42.8 {+-} 5.1% RR cycle, SD of time to peak motion was 3.5 {+-} 1.4% RR cycle and bandwidth was 18.2 {+-} 6.0% RR cycle. No significant gender-related differences or differences between rest and post-stress acquisition were found for the dyssynchrony parameters. Discrepancies between the normal and abnormal populations were most profound for the mean wall motion (p value <0.001), SD of time to peak motion (p value <0.001) and bandwidth (p value <0.001). It is feasible to quantify ventricular dyssynchrony in MPS using the geometrical approach as implemented by Corridor4DM. (orig.)

  1. Transmural mechanics at left ventricular epicardial pacing site

    OpenAIRE

    Ashikaga, Hiroshi; Omens, Jeffrey H.; Ingels, Neil B., Jr.; Covell, James W.

    2004-01-01

    Left ventricular (LV) epicardial pacing acutely reduces wall thickening at the pacing site. Because LV epicardial pacing also reduces transverse shear deformation, which is related to myocardial sheet shear, we hypothesized that impaired end-systolic wall thickening at the pacing site is due to reduction in myocardial sheet shear deformation, resulting in a reduced contribution of sheet shear to wall thickening. We also hypothesized that epicardial pacing would reverse the transmural mechanic...

  2. 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.

  3. Water Stress and Foliar Boron Application Altered Cell Wall Boron and Seed Nutrition in Near-Isogenic Cotton Lines Expressing Fuzzy and Fuzzless Seed Phenotypes

    Science.gov (United States)

    2015-01-01

    Our previous research, conducted under well-watered conditions without fertilizer application, showed that fuzziness cottonseed trait resulted in cottonseed nutrition differences between fuzzy (F) and fuzzless (N) cottonseed. Under water stress conditions, B mobility is further limited, inhibiting B movement within the plant, affecting seed nutrition (quality). Therefore, we hypothesized that both foliar B and water stress can affect B mobility, altering cottonseed protein, oil, and mineral nutrition. The objective of the current research was to evaluate the effects of the fuzziness seed trait on boron (B) and seed nutrition under water stress and foliar B application using near-isogenic cotton lines (NILs) grown in a repeated greenhouse experiment. Plants were grown under-well watered conditions (The soil water potential was kept between -15 to -20 kPa, considered field capacity) and water stress conditions (soil water potential between -100 and -150 kPa, stressed conditions). Foliar B was applied at a rate of 1.8 kg B ha-1 as H3BO3. Under well-watered conditions without B the concentrations of seed oil in N lines were higher than in F lines, and seed K and N levels were lower in N lines than in F lines. Concentrations of K, N, and B in leaves were higher in N lines than in F lines, opposing the trend in seeds. Water-stress resulted in higher seed protein concentrations, and the contribution of cell wall (structural) B to the total B exceeded 90%, supporting the structural role of B in plants. Foliar B application under well-watered conditions resulted in higher seed protein, oil, C, N, and B in only some lines. This research showed that cottonseed nutrition differences can occur due to seed fuzziness trait, and water stress and foliar B application can alter cottonseed nutrition. PMID:26098564

  4. Anatomy of the female pelvic viscera before and after transobturator tape procedures and anterior vaginal wall repair in patients with stress urinary incontinence

    Directory of Open Access Journals (Sweden)

    Laketić Darko

    2016-01-01

    Full Text Available Anatomy of the female pelvic viscera was investigated before and after the Tension free Vaginal tape (TVT-O. Forty patients were included in the study. Surgery was performed between 2009 and 2012 in Clinic of Urology (Clinical Center Nis and Department of Urology (Municipal Hospital Prokuplje. Stress Urinary Incontinence (SUI and anterior vaginal wall prolapse was confirmed in all patients. In all patients with anterior vaginal wall prolapse (grade≥2 both tension free vaginal tape (TVT-O and anterior vaginal wall repair were performed. Pelvic Organ Prolapse Quantification (POPQ system was used for the evaluation of prolapse before and after the surgery. Mean age of patients was 61 years. Spinal anesthesia was performed in thirty patients and general anesthesia in 10 patients. Intraoperative blood loss was under 50 ml. There were no bladder, nerve and blood vessels injuries . Thirty eight out of forty patients (95% were satisfied with the outcome of the surgery. There was a significant correction of prolapse after the surgery. Recurrence of prolapse was found in patients with the high grade prolapse before the surgery, as well as, in patients with the history of previous anterior vaginal repair. Pelvic organ prolapse, congenital or acquired, is supported by the congenital weakness of the pelvic floor.

  5. QTLs for cell wall-bound phenolics in relation to the photosynthetic apparatus activity and leaf water status under drought stress at different growth stages of triticale.

    Science.gov (United States)

    Hura, Tomasz; Tyrka, Mirosław; Hura, Katarzyna; Ostrowska, Agnieszka; Dziurka, Kinga

    2017-04-01

    The present study aimed at identifying the regions of triticale genome responsible for cell wall saturation with phenolic compounds under drought stress during vegetative and generative growth. Moreover, the loci determining the activity of the photosynthetic apparatus, leaf water content (LWC) and osmotic potential (Ψ o) were identified, as leaf hydration and functioning of the photosynthetic apparatus under drought are associated with the content of cell wall-bound phenolics (CWPh). Compared with LWC and Ψ o, CWPh fluctuations were more strongly associated with changes in chlorophyll fluorescence. At the vegetative stage, CWPh fluctuations were due to the activity of three loci, of which only QCWPh.4B was also related to changes in F v/F m and ABS/CSm. In the other QTLs (QCWPh.6R.2 and QCWPh.6R.3), the genes of these loci determined also the changes in majority of chlorophyll fluorescence parameters. At the generative stage, the changes in CWPh in loci QCWPh.4B, QCWPh.3R and QCWPh.6R.1 corresponded to those in DIo/CSm. The locus QCWPh.6R.3, active at V stage, controlled majority of chlorophyll fluorescence parameters. This is the first study on mapping quantitative traits in triticale plants exposed to drought at different stages of development, and the first to present the loci for cell wall-bound phenolics.

  6. Association of Right Ventricular Pressure and Volume Overload with Non-Ischemic Septal Fibrosis on Cardiac Magnetic Resonance.

    Directory of Open Access Journals (Sweden)

    Jiwon Kim

    Full Text Available Non-ischemic fibrosis (NIF on cardiac magnetic resonance (CMR has been linked to poor prognosis, but its association with adverse right ventricular (RV remodeling is unknown. This study examined a broad cohort of patients with RV dysfunction, so as to identify relationships between NIF and RV remodeling indices, including RV pressure load, volume and wall stress.The population comprised patients with RV dysfunction (EF 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001.Among wall stress components, NIF was independently associated with RV chamber dilation and afterload, supporting the concept that NIF is linked to adverse RV chamber remodeling.

  7. Variable Myocardial Response to Load Stresses in Infants with Single Left Ventricular Anatomy: Influence of Initial Physiology and Surgical Palliative Strategy.

    Science.gov (United States)

    Horriat, Narges L; Deatsman, Sara L; Stelter, Jessica; Frommelt, Peter C; Hill, Garick D

    2016-12-01

    Initial surgical strategies in neonates with single left ventricular (LV) anatomy vary based on adequacy of pulmonary and systemic blood flow. Differing myocardial responses to these strategies, as reflected in indices of systolic function, ventricular size, and mass have not been well defined. We sought to evaluate single LV myocardial response to varied physiology and initial palliation and determine whether the response is consistent and predictable. Infants with single LV physiology were divided based on neonatal palliation: no palliation/PA band (NO); BT shunt only (BT); or Norwood procedure (NP). Echo measures were obtained at presentation, early post-bidirectional Glenn (BDG), late post-BDG follow-up, and post-Fontan procedure. Measures included ejection fraction, LV mass indexed to height(2.7) and end diastolic volume indexed to body surface area, and mass/volume ratio. The cohort included 38 children (13 NO, 13 BT, 12 NP). Ejection fraction was similar but depressed in all groups at all stages. LV mass was higher in the NP group than the BT group at early post-BDG (p = 0.03) and higher than both BT and NO groups (p < 0.01) at late post-BDG, but the difference was resolved by post-Fontan follow-up. The NP group had the most remarkable remodeling in LV size from BDG to Fontan, suggesting that volume unloading is most valuable in this subgroup. Ventricular remodeling can be identified by echocardiography in children with single LV physiology, despite variable initial surgical palliative strategies. Importantly, these initial surgical strategies do not result in significant differences after Fontan palliation during early childhood.

  8. A modified vaginal wall patch sling technique as a first-line surgical approach for genuine stress incontinence with urethral hypermobility: long-term follow up.

    Science.gov (United States)

    Mikhail, Magdy S; Rosa, Hector; Packer, Paul; Palan, Prabhudas; Lazarou, George

    2004-01-01

    We describe our long-term outcome for patients with genuine stress incontinence (GSI) and urethral hypermobility using a modified vaginal wall patch sling technique. Fifty-three patients were studied. Preoperatively, all patients had a positive standing stress test and urethral hypermobility on Q-tip testing. On urodynamics, all patients had absence of detrusor contractions on subtracted cystometry. The mean age of the patients was 45+10.2 years. Forty-four patients demonstrated complete symptomatic and urodynamic improvement. Five patients had a noticeable failure observed within the first 12 months of follow up and four patients developed later recurrence despite initial success. The overall success rate after 5 years of follow up was 83% (n=44/53). The modified vaginal wall patch sling technique appears to have a good long-term success rate with low operative morbidity and minimal postoperative voiding dysfunction. The patch sling can be used as a first-line surgical approach for GSI with urethral hypermobility and be combined with other vaginal surgery.

  9. Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance.

    Science.gov (United States)

    Smedema, Jan-Peter; van Geuns, Robert-Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J G M

    2017-11-01

    Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast-enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast-enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non-invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P Right ventricular enhancement correlated with systolic ventricular dysfunction (P Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

  10. Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Tassi, Eduardo Marinho, E-mail: etassi@ibest.com.br [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Continentino, Marcelo Abramoff [Hospital Frei Galvão, Guaratinguetá, SP (Brazil); Nascimento, Emília Matos do; Pereira, Basílio de Bragança [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Coppe - Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia - UFRJ, Rio de Janeiro, RJ (Brazil); Pedrosa, Roberto Coury [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2014-05-15

    Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis. To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia. Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram. The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001). Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.

  11. Experimental and CFD Simulation Studies of Wall Shear Stress for Different Impeller Configurations and MBR Activated Sludge

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Chan, C.C.V.; Bentzen, Thomas Ruby

    2012-01-01

    in an MBR. Nevertheless, proper experimental validation is required to validate CFD simulation. In this work experimental measurements of shear stress induced by impellers at a membrane surface were made with an electrochemical approach and the results were used to validate CFD simulations. As good results...... appealing for full-scale applications. It has been widely demonstrated that the filtration performances in MBRs can be improved by understanding the shear stress over the membrane surface. Modern tools such as Computational Fluid Dynamics (CFD) can be used to diagnose and understand the shear stress...... were attained with the CFD model (

  12. Alteration of cell-wall porosity is involved in osmotic stress-induced enhancement of aluminium resistance in common bean (Phaseolus vulgaris L.)

    Science.gov (United States)

    Yang, Zhong-Bao; Eticha, Dejene; Rao, Idupulapati Madhusudana; Horst, Walter Johannes

    2010-01-01

    Aluminium (Al) toxicity and drought are the two major abiotic stress factors limiting common bean production in the tropics. Using hydroponics, the short-term effects of combined Al toxicity and drought stress on root growth and Al uptake into the root apex were investigated. In the presence of Al stress, PEG 6000 (polyethylene glycol)-induced osmotic (drought) stress led to the amelioration of Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1. PEG 6000 (>> PEG 1000) treatment greatly decreased Al accumulation in the 1 cm root apices even when the roots were physically separated from the PEG solution using dialysis membrane tubes. Upon removal of PEG from the treatment solution, the root tips recovered from osmotic stress and the Al accumulation capacity was quickly restored. The PEG-induced reduction of Al accumulation was not due to a lower phytotoxic Al concentration in the treatment solution, reduced negativity of the root apoplast, or to enhanced citrate exudation. Also cell-wall (CW) material isolated from PEG-treated roots showed a low Al-binding capacity which, however, was restored after destroying the physical structure of the CW. The comparison of the Al3+, La3+, Sr2+, and Rb+ binding capacity of the intact root tips and the isolated CW revealed the specificity of the PEG 6000 effect for Al. This could be due to the higher hydrated ionic radius of Al3+ compared with other cations (Al3+ >> La3+ > Sr2+ > Rb+). In conclusion, the results provide circumstantial evidence that the osmotic stress-inhibited Al accumulation in root apices and thus reduced Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1 is related to the alteration of CW porosity resulting from PEG 6000-induced dehydration of the root apoplast. PMID:20511277

  13. Simulation of bending stress variation in long buried thick-walled pipes under the earth’s movement using combined linear dynamics and beam theories

    Directory of Open Access Journals (Sweden)

    Salau Tajudeen A.O.

    2014-01-01

    Full Text Available This study reported a simulation approach to the understanding of the interactions between a buried pipe and the soil system by computing the bending stress variation of harmonically-excited buried pipes. The established principles of linear dynamics theory and simple beam theory were utilised in the analysis of the problem of buried pipe bending stress accumulation and its dynamics. With regards to the parameters that influence the bending stress variations, the most important are the isolation factor, uniform external load, and the corresponding limiting conditions. The simulated mathematical expressions, containing static and dynamic parameters of the buried pipe and earth, were coded in Fortran programming language and applied in the simulation experiment. The results obtained showed that harmonically-excited buried thick-walled pipe became stable and effective when the ratio of the natural frequency of vibration to the forced frequency is greater than 2.0, whenever the damped factor is used as the control parameter for the maximum bending stress. The mirror image of the stress variation produces variation in the location of the maximum bending stress in quantitative terms. The acceptable pipe materials for the simulated cases must have yield strength in bending greater than or equal to 13.95 MPa. The results obtained in this work fill a gap in the literature and will be useful to pipeline engineers and designers, as well as to environmental scientists in initialising and controlling environmental issues and policy formulation concerning the influence of buried pipe on the soil and water in the environment.

  14. Effects of foliar boron application on seed composition, cell wall boron, and seed δ 15N and δ 13C isotopes in water-stressed soybean plants

    Directory of Open Access Journals (Sweden)

    Nacer eBellaloui

    2013-07-01

    Full Text Available Limited information is available on the effects of foliar boron (B application on soybean seed composition. The objective of this research was to investigate the effects of foliar B on seed composition (protein, oil, fatty acids, and sugars. Our hypothesis was that since B is involved in nitrogen and carbon metabolism, it may impact seed composition. A repeated greenhouse experiment was conducted where half of the soybean plants was exposed to water stress (WS and the other half was well watered. Foliar boron (FB in the form of boric acid was applied twice at a rate of 1.1 kg ha-1. The first application was during flowering stage, and the second application was during seed-fill stage. Treatments were water stressed plants with no FB (WS-B; water stressed plants with FB (WS+B; watered plants without FB (W-B, and watered plants with FB (W+B. The treatment W-B was used as a control. Comparing with WS-B plants, B concentration was the highest in leaves and seed of W+B plants (84% increase in leaves and 73% in seed. Seeds of W+B plants had higher protein (11 % increase, oleic acid (27% increase, sucrose (up to 40 % increase, glucose, and fructose comparing with W-B. However, seed stachyose concentrations increased by 43% in WS-B plants seed compared with W-B plants. Cell wall (structural B concentration in leaves was higher in all plants under water stress, especially in WS-B plants where the percentage of cell wall B reached up to 90 %. Water stress changed seed δ15N and δ 13C values in both B applied and non-B applied plants, indicating possible effects on nitrogen and carbon metabolism. This research demonstrated that FB increased B accumulation in leaves and seed, and altered seed composition of well watered and water stressed plants, indicating a possible involvement of B in seed protein, and oleic and linolenic fatty acids. Further research is needed to explain mechanisms of B involvement in seed protein and fatty acids.

  15. Right ventricular hydatid cyst ruptured to pericardium

    Directory of Open Access Journals (Sweden)

    Feridoun Sabzi

    2015-01-01

    Full Text Available Cardiac hydatidosis is rare presentation of body hydatidosis. Incidence of cardiac involvements range from 5% to 5% of patients with hydatid disease. Most common site of hydatid cyst in heart is interventricular septum and left ventricular free wall. Right ventricular free wall involvement by cyst that ruptured to pericardial cavity is very rare presentation of hydatid cyst. Cardiac involvement may have serious consequences such as rupture to blood steam or pericardial cavity. Both the disease and its surgical treatment carry a high complication rate, including rupture leading to cardiac tamponade, anaphylaxis and also death. In the present report, a 43-year-old man with constrictive pericarditis secondary to a pericardial hydatid cyst is described.

  16. [Head to head comparison of dobutamine alone and combined with nitrate stress echocardiography and 99mTc-MIBI/18FDG myocardial SPECT image for diagnosis of viable myocardium in patients with severe left ventricular dysfunction].

    Science.gov (United States)

    Yang, Yue-jin; Yang, Wei-xian; Shi, Rong-fang; Hu, Feng-huan; You, Shi-jie; Tian, Yue-qin; He, Zuo-xiang; Wang, Yan-wu; Ye, Ling; Chen, Ji-lin; Gao, Run-lin; Chen, Zai-jia

    2005-04-01

    This study was sought to compare the sensitivity, specificity and accuracy of (1) dual isotope simultaneous acquisition single-photon emission computed tomography (DISA SPECT) myocardial image with (99m)Tc-sestamibi/(18)F-fluorodeoxyglucose ((99m)Tc-MIBI/(18)FDG); (2) low dose dobutamine alone and combined with Isosorbide Dinitrate (ISDN: Isoket) stress two dimensional echocardiography (2DE) to predict regional movement recovery after revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction. Twenty-six patients (mean age 51 +/- 8 years, male 25, female 1) with OMI and severe left ventricular dysfunction (mean left ventricular ejection fraction, LVEF (38.6% +/- 4.9%) underwent low dose dobutamine 10 microg x kg(-1) x min(-1) (Dob10 microg) and ISDN (286 +/- 31 microg/min) combined with Dob5 microg (ISDN-Dob 5 microg) 2DE and DISA SPECT within one week. In echocardiogram and DISA SPECT images: the left ventricle (LV) was divided into 16 segments. The semi-quantitative scoring system was used for both images. Myocardial viability was defined as an improvement of at least >or= 1 grade in at least two contiguous segments at rest 2DE after CRV. The viable segments detecting rate with stress 2DE and DISA SPECT were compared. Compared with the results of post-CRV, the sensitivity, specificity and accuracy of detecting viable segments of two methods were calculated. Among 272 abnormal segments in 26 patients, 156 (57.4%) segments showed contractile improvement after CRV. The viable segments detecting rate with DISA SPECT was 72.4% (134/254), which was significantly higher than the contractile improved rate after CRV (P 0.05). With DISA SPECT, the sensitivity, specificity and accuracy were 93.7%, 55% and 76.8%, respectively. Compared with DISA SPECT, Dob10 microg 2DE showed similar sensitivity (88.6%), specificity (64.2%) and the accuracy (77.9%). When ISDN combined with Dob5 microg, the sensitivity (91.4%), specificity

  17. Right ventricular involvement in feline hypertrophic cardiomyopathy.

    Science.gov (United States)

    Schober, K E; Savino, S I; Yildiz, V

    2016-12-01

    To evaluate right ventricular (RV) wall thickness and chamber dimensions in cats with hypertrophic cardiomyopathy (HCM). One hundred fifty-one healthy control cats and 200 cats with HCM. Retrospective, observational, clinical cohort study. Two-dimensional echocardiograms from all cats were analyzed. Right atrial diameter, RV free wall thickness, and RV chamber diameter were quantified using multiple imaging views. Conventional (mean ± 2 standard deviations) and allometrically scaled (Y = a × M b ) reference values were determined in normal cats and compared to values found in cats with HCM. Linear and logistic regression, multivariate regression, and mixed model analysis were performed to identify associations between RV wall thickness and severity of left ventricular (LV) hypertrophy, clinical severity of HCM, and presence of pleural effusion. Mean RV wall thickness was increased in HCM (p0.05) in control cats. Increased RV wall thickness is common in cats with HCM and relates to severity of LV hypertrophy and clinical status. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Diastolic Filling Reserve Preservation Using a Semispherical Dacron Patch for Repair of Anteroapical Left Ventricular Aneurysm.

    Science.gov (United States)

    Hartmann, Rebecca; Auf der Maur, Christoph; Toggweiler, Stefan; Brunner, Christian; Jamshidi, Peiman; Mueller, Xavier; Tavakoli, Reza

    2016-07-01

    In postinfarction left ventricular aneurysm, abnormal geometry and desynchronized wall motion may cause a highly inefficient pump function. The traditional endoventricular patch plasty according to the Dor technique might result in a truncated and restrictive left ventricular cavity in small adults. We report a modified technique of left ventricular anteroapical aneurysm repair by using a semispherical reshaping patch to restore the left ventricular geometry. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  19. Arrhythmogenic right ventricular dysplasia masquerading as an abdominal episode.

    Science.gov (United States)

    Kaya, Mehmet Gungor; Yalcin, Ridvan; Ozin, Bulent; Altunkan, Sekip; Cengel, Atiye

    2007-01-01

    A 19-year-old woman presented with abdominal pain. Aside from epigastric tenderness, the patient's physical examination was unremarkable. She developed ventricular tachycardia with left bundle branch block morphology shortly after admission. Echocardiography revealed a thin, enlarged, and hypokinetic right ventricle. Electron beam computed tomography demonstrated hypodense areas in the right ventricular free wall suggestive of fatty infiltration, which suggested arrhythmogenic right ventricular dysplasia. The diagnosis was confirmed with the use of cardiac magnetic resonance imaging. The patient received an implantable cardioverter-defibrillator. This case illustrates a noncardiac presentation of a rare yet treatable cardiac condition.

  20. What Next After Failed Septal Ventricular Tachycardia Ablation?

    Directory of Open Access Journals (Sweden)

    Laurent Roten, MD

    2012-07-01

    Full Text Available Ablation of ventricular tachycardia (VT by conventional radiofrequency ablation can be impossible if the ventricular wall at the targeted ablation site is very thick, as for example the ventricular septum. We present a case of a patient with incessant, non-sustained slow VT originating from the septal part of the lower outflow tracts. Radiofrequency catheter ablation from both ventricles as well as from the anterior cardiac vein were not successful. Both high power radiofrequency ablation and bipolar radiofrequency ablation neither were successfull. Finally, ethanol ablation of the first septal perforator successfully terminated arrhythmia. We discuss the possibilities to overcome failed conventional radiofrequency VT ablation of a septal focus.

  1. Left and right ventricular diastolic function in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Rudhani Ibrahim

    2010-01-01

    Full Text Available The aim of this prospective study was the assessment of left ventricular and right ventricular diastolic function in patients on hemodialysis (HD and the correlation of this func-tion with the duration of HD. The study included 42 patients (22 females and 20 males with chro-nic renal failure (CRF, treated with HD, and 40 healthy subjects (24 females and 16 males with no history of cardiovascular disease and with normal renal function, who constituted the control group. The groups were matched for age and sex. All study patients and control subjects under-went detailed history taking and physical examination. They also underwent electrocardiogram, echocardiography and biochemical and hematological blood analyses. Significant differences were noted between the two groups in the two-dimensional and M-mode echocardiography findings concerning aortic root dimension, transverse diameter of the left atrium, thickness of the inter-ventricular septum, thickness of the left ventricular posterior wall, left ventricular diastolic diameter, left ventricular systolic diameter, shortening fraction, ejection fraction as well as findings from the pulse Doppler study, including E wave, A wave, E/A ratio, deceleration time of E wave (DT-E, acceleration time of E wave (AT-E, tricuspid E and A waves (E tr and A tr and E tr /A tr , ratio. There were significant changes in HD patients without arterial hypertension as well in the control group subjects. Our study suggests that the left ventricular and left atrial dimensions as well as the left ventricular wall thickness are augmented in patients with CRF treated with HD compared with the control group. Additionally, the left and right ventricular diastolic function is also reduced in these patients. These differences were also noted in patients with CRF without arterial hypertension. Left ventricular diastolic dysfunction had no correlation with the duration of HD.

  2. A novel four-dimensional angiographic approach to assess dynamic superficial wall stress of coronary arteries in vivo

    DEFF Research Database (Denmark)

    Wu, Xinlei; von Birgelen, Clemens; Muramatsu, Takashi

    2017-01-01

    it for the first time in two clinical cases to investigate the potential relationship between dynamic stress concentration at baseline and plaque rupture during acute coronary syndrome (ACS) several months later. METHODS AND RESULTS: Three-dimensional angiographic reconstructions of the interrogated arteries were...... performed at several phases of the cardiac cycle, followed by finite element analysis to obtain the dynamic SWS data. The peak stress at baseline was found at the distal and proximal lesion longitudinal shoulders, being 121.8kPa and 98.0kPa, respectively. Intriguingly, in both cases, the sites...

  3. Pattern and Impact of Altered Regional Myocardial Excursion on Global Ventricular Performance After First-Time Acute Anterior Wall Myocardial Infarction by Real-Time Three-Dimensional Echocardiography

    Directory of Open Access Journals (Sweden)

    Chung-Lieh Hung

    2008-12-01

    Conclusion: Regional wall motion abnormalities quantified by RT-3DE are clinically convenient and feasible in both MI patients and the normal population. This rapid and objective quantification may also help discriminate abnormal from normal regional and global functions after infarction and, therefore, has the potential to be an attractive solution for clinical diagnosis.

  4. Atlas-Based Ventricular Shape Analysis for Understanding Congenital Heart Disease.

    Science.gov (United States)

    Farrar, Genevieve; Suinesiaputra, Avan; Gilbert, Kathleen; Perry, James C; Hegde, Sanjeet; Marsden, Alison; Young, Alistair A; Omens, Jeffrey H; McCulloch, Andrew D

    2016-12-01

    Congenital heart disease is associated with abnormal ventricular shape that can affect wall mechanics and may be predictive of long-term adverse outcomes. Atlas-based parametric shape analysis was used to analyze ventricular geometries of eight adolescent or adult single-ventricle CHD patients with tricuspid atresia and Fontans. These patients were compared with an "atlas" of non-congenital asymptomatic volunteers, resulting in a set of z-scores which quantify deviations from the control population distribution on a patient-by-patient basis. We examined the potential of these scores to: (1) quantify abnormalities of ventricular geometry in single ventricle physiologies relative to the normal population; (2) comprehensively quantify wall motion in CHD patients; and (3) identify possible relationships between ventricular shape and wall motion that may reflect underlying functional defects or remodeling in CHD patients. CHD ventricular geometries at end-diastole and end-systole were individually compared with statistical shape properties of an asymptomatic population from the Cardiac Atlas Project. Shape analysis-derived model properties, and myocardial wall motions between end-diastole and end-systole, were compared with physician observations of clinical functional parameters. Relationships between altered shape and altered function were evaluated via correlations between atlas-based shape and wall motion scores. Atlas-based shape analysis identified a diverse set of specific quantifiable abnormalities in ventricular geometry or myocardial wall motion in all subjects. Moreover, this initial cohort displayed significant relationships between specific shape abnormalities such as increased ventricular sphericity and functional defects in myocardial deformation, such as decreased long-axis wall motion. These findings suggest that atlas-based ventricular shape analysis may be a useful new tool in the management of patients with CHD who are at risk of impaired ventricular

  5. Evaluation of 3D blood flow patterns and wall shear stress in the normal and dilated thoracic aorta using flow-sensitive 4D CMR

    Directory of Open Access Journals (Sweden)

    Bürk Jonas

    2012-12-01

    Full Text Available Abstract Background The purpose of this study was to investigate 3D flow patterns and vessel wall parameters in patients with dilated ascending aorta, age-matched subjects, and healthy volunteers. Methods Thoracic time-resolved 3D phase contrast CMR with 3-directional velocity encoding was applied to 33 patients with dilated ascending aorta (diameter ≥40 mm, age=60±16 years, 15 age-matched normal controls (diameter ≤37 mm, age=68±7.5 years and 15 young healthy volunteers (diameter ≤30 mm, age=23±2 years. 3D blood flow was visualized and flow patterns were graded regarding presence of supra-physiologic-helix and vortex flow using a semi-quantitative 3-point grading scale. Blood flow velocities, regional wall shear stress (WSS, and oscillatory shear index (OSI were quantified. Results Incidence and strength of supra-physiologic-helix and vortex flow in the ascending aorta (AAo was significantly higher in patients with dilated AAo (16/33 and 31/33, grade 0.9±1.0 and 1.5±0.6 than in controls (2/15 and 7/15, grade 0.2 ± 0.6 and 0.6 ± 0.7, PPPPPPPP Conclusions Increase in AAo diameter is significantly correlated with the presence and strength of supra-physiologic-helix and vortex formation in the AAo, as well with decrease in systolic WSS and increase in OSI.

  6. Hydroxylation of multi-walled carbon nanotubes: Enhanced biocompatibility through reduction of oxidative stress initiated cell membrane damage, cell cycle arrestment and extrinsic apoptotic pathway.

    Science.gov (United States)

    Liu, Zhenbao; Liu, Yanfei; Peng, Dongming

    2016-10-01

    Modification of CNTs with hydroxyl group promotes their applications in biomedical area. However, the impact of hydroxylation on their biocompatibility is far from being completely understood. In this study, we carried out a comprehensive evaluation of hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) on the human normal liver L02 cell line, and compared it with that of pristine multi-walled carbon nanotubes (p-MWCNTs). Results demonstrated that compared with p-MWCNTs, MWCNTs-OH induced significantly lower oxidative stress as indicated by the level of intracellular antioxidant glutathione (GSH), subsequently lead to less cell membrane damage as demonstrated by lactate dehydrogenase (LDH) leakage assay, and showed slightly decreased arrestment of cell cycle distribution at G0/G1. More interestingly, MWCNTs-OH exhibited significantly lower tendency to activate caspase-8, a key molecule involved in the extrinsic apoptotic pathway. All these in vitro results demonstrated that hydroxylation of MWCNTs enhanced their biocompatibility compare with p-MWCNTs. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Transcriptome analysis of WRKY gene family in Oryza officinalis Wall ex Watt and WRKY genes involved in responses to Xanthomonas oryzae pv. oryzae stress.

    Directory of Open Access Journals (Sweden)

    Chunmiao Jiang

    Full Text Available Oryza officinalis Wall ex Watt, a very important and special wild rice species, shows abundant genetic diversity and disease resistance features, especially high resistance to bacterial blight. The molecular mechanisms of bacterial blight resistance in O. officinalis have not yet been elucidated. The WRKY transcription factor family is one of the largest gene families involved in plant growth, development and stress response. However, little is known about the numbers, structure, molecular phylogenetics, and expression of the WRKY genes under Xanthomonas oryzae pv. oryzae (Xoo stress in O. officinalis due to lacking of O. officinalis genome. Therefore, based on the RNA-sequencing data of O. officinalis, we performed a comprehensive study of WRKY genes in O. officinalis and identified 89 OoWRKY genes. Then 89 OoWRKY genes were classified into three groups based on the WRKY domains and zinc finger motifs. Phylogenetic analysis strongly supported that the evolution of OoWRKY genes were consistent with previous studies of WRKYs, and subgroup IIc OoWRKY genes were the original ancestors of some group II and group III OoWRKYs. Among the 89 OoWRKY genes, eight OoWRKYs displayed significantly different expression (>2-fold, p<0.01 in the O. officinalis transcriptome under Xoo strains PXO99 and C5 stress 48 h, suggesting these genes might play important role in PXO99 and C5 stress responses in O. officinalis. QRT-PCR analysis and confirmation of eight OoWRKYs expression patterns revealed that they responded strongly to PXO99 and C5 stress 24 h, 48 h, and 72 h, and the trends of these genes displaying marked changes were consistent with the 48 h RNA-sequencing data, demonstrated these genes played important roles in response to biotic stress and might even involved in the bacterial blight resistance. Tissue expression profiles of eight OoWRKY genes revealed that they were highly expressed in root, stem, leaf, and flower, especially in leaf (except OoWRKY71

  8. Internal stress induced metallization of single-walled carbon nanotubes in a nanotube/glass conducting composite.

    Science.gov (United States)

    Balaji, Sathravada; Debnath, Radhaballabh

    2011-10-14

    Single-walled carbon nanotubes (SWCNTs) have been incorporated into a (Pb, Zn)-phosphate glass host by a melt-quenching technique. Studies of the optical and electronic properties show that the nanotubes in the composite have suffered conformational deformations and attained a band structure of quasimetallic type, making the composite a good electrical conductor. Possible strains in the nanotubes of the composite such as radial compression, torsion and bending have been considered and their role in modulating the band structures has been analyzed by judging the change in band gap energies (ΔE) of the deformed SWCNTs using an equation which is based on the π-electron tight binding model. The effect of σ*-π* hybridization due to the radial compression in generating the metallicity is also discussed. The carrier transport in the composite above room temperature has been shown to be dominated by fluctuation induced tunneling.

  9. Quantitative and qualitative characteristics of cell wall components and prenyl lipids in the leaves of Tilia x euchlora trees growing under salt stress.

    Directory of Open Access Journals (Sweden)

    Anna Milewska-Hendel

    Full Text Available The study was focused on assessing the presence of arabinogalactan proteins (AGPs and pectins within the cell walls as well as prenyl lipids, sodium and chlorine content in leaves of Tilia x euchlora trees. The leaves that were analyzed were collected from trees with and without signs of damage that were all growing in the same salt stress conditions. The reason for undertaking these investigations was the observations over many years that indicated that there are trees that present a healthy appearance and trees that have visible symptoms of decay in the same habitat. Leaf samples were collected from trees growing in the median strip between roadways that have been intensively salted during the winter season for many years. The sodium content was determined using atomic spectrophotometry, chloride using potentiometric titration and poly-isoprenoids using HPLC/UV. AGPs and pectins were determined using immunohistochemistry methods. The immunohistochemical analysis showed that rhamnogalacturonans I (RG-I and homogalacturonans were differentially distributed in leaves from healthy trees in contrast to leaves from injured trees. In the case of AGPs, the most visible difference was the presence of the JIM16 epitope. Chemical analyses of sodium and chloride showed that in the leaves from injured trees, the level of these ions was higher than in the leaves from healthy trees. Based on chromatographic analysis, four poly-isoprenoid alcohols were identified in the leaves of T. x euchlora. The levels of these lipids were higher in the leaves from healthy trees. The results suggest that the differences that were detected in the apoplast and symplasm may be part of the defensive strategy of T. x euchlora trees to salt stress, which rely on changes in the chemical composition of the cell wall with respect to the pectic and AGP epitopes and an increased synthesis of prenyl lipids.

  10. Quantitative and qualitative characteristics of cell wall components and prenyl lipids in the leaves of Tilia x euchlora trees growing under salt stress.

    Science.gov (United States)

    Milewska-Hendel, Anna; Baczewska, Aneta H; Sala, Katarzyna; Dmuchowski, Wojciech; Brągoszewska, Paulina; Gozdowski, Dariusz; Jozwiak, Adam; Chojnacki, Tadeusz; Swiezewska, Ewa; Kurczynska, Ewa

    2017-01-01

    The study was focused on assessing the presence of arabinogalactan proteins (AGPs) and pectins within the cell walls as well as prenyl lipids, sodium and chlorine content in leaves of Tilia x euchlora trees. The leaves that were analyzed were collected from trees with and without signs of damage that were all growing in the same salt stress conditions. The reason for undertaking these investigations was the observations over many years that indicated that there are trees that present a healthy appearance and trees that have visible symptoms of decay in the same habitat. Leaf samples were collected from trees growing in the median strip between roadways that have been intensively salted during the winter season for many years. The sodium content was determined using atomic spectrophotometry, chloride using potentiometric titration and poly-isoprenoids using HPLC/UV. AGPs and pectins were determined using immunohistochemistry methods. The immunohistochemical analysis showed that rhamnogalacturonans I (RG-I) and homogalacturonans were differentially distributed in leaves from healthy trees in contrast to leaves from injured trees. In the case of AGPs, the most visible difference was the presence of the JIM16 epitope. Chemical analyses of sodium and chloride showed that in the leaves from injured trees, the level of these ions was higher than in the leaves from healthy trees. Based on chromatographic analysis, four poly-isoprenoid alcohols were identified in the leaves of T. x euchlora. The levels of these lipids were higher in the leaves from healthy trees. The results suggest that the differences that were detected in the apoplast and symplasm may be part of the defensive strategy of T. x euchlora trees to salt stress, which rely on changes in the chemical composition of the cell wall with respect to the pectic and AGP epitopes and an increased synthesis of prenyl lipids.

  11. Fragmented QRS and Left Ventricular Geometry in Hypertensive Patients

    Directory of Open Access Journals (Sweden)

    Lütfü Bekar

    2013-08-01

    Full Text Available Introduction: Fragmented QRS is a depolarization abnormality detected with routin ECG recording. It is related with conduction defect which occurs after myocardial fibrosis. In the left ventricular hypertrophy, an excessive amount of collagen accumulates in the interstitium when the myocytes became hypertrophied, resulting in myocardial fibrosis. In this study, we aimed to investigate the relationship of fragmented QRS which was detected on ECG recordings of the hypertensive patients with the left ventricular geometry.Patients and Methods: Essential hypertension patients referred to our hospital on outpatient bases were included in the study. 12-lead resting ECG was taken in all the patients. Left ventricular geometry defined using left ventricular mass index and relative wall thickness with transthorasic echocardiography.Results: Sixy seven patients with fragmented QRS and 63 patients without fragmented QRS included the study. We found that patients in the group with fragmented QRS detected have a wider mean left atrium diameter, greater left ventricular mass and left ventricular mass index compared with the group without fragmented QRS. Concentric and eccentric hypertrophy were more common in fragmented QRS group, while normal geometry and concentric remodelling have greater rates in the normal group.Conclusion: Left ventricular hypertrophy is observed more frequently in the patients with fragmented QRS than without fragmented QRS. This may be associated with the increased myocardial fibrosis in the left ventricular hypertrophy. Existence of fragmented QRS can be used for risk stratification in the hypertensive patients.

  12. Investigation of Mechanical and Thermal Properties of Polymer Composites Reinforced by Multi-Walled Carbon Nanotube for Reduction of Residual Stresses

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Ghasemi

    2014-08-01

    Full Text Available The micromechanical models are used to investigate mechanical and thermal properties of a polymer matrix nanocomposite containing multi-walled carbon nanotubes (MWCNT in their effects to reduce residual stresses in nanocomposites. To do this, first nanotubes with different weights and volume fractions were dispersed in ML-506 epoxy resin. By using different micromechanical models, the effect additional nanotubes on elastic modulus and coefficient of thermal expansion (CTE of nanotubes/epoxy were studied as critical parameters. Comparing the model and available experimental results, the modified Halpin-Tsai model and the modified Schapery model were chosen to calculate the mechanical and thermal properties of the nanocomposites. Then, using the matrix reinforced with MWCNT and classical micromechanics models the elastic modulus and coefficients of thermal expansion of the nanocomposites were determined for a single orthotropic ply. The results showed that the rule of mixture (ROM and Hashin-Rosen model to determine the longitudinal and transverse elastic moduli and Van Fo Fy model to calculate the coefficient of thermal expansion were in good agreements with the experimental results of a single-layer nanocomposite. Finally, the classical laminated plate theory (CLPT was used to calculate the residual stresses of the CNT/carbon fiber/epoxy composites with different weights and volume fractions of MWCNT for angle-ply, cross-ply and quasi-isotropic laminated composite materials. The results showed that residual stresses were reduced using a maximum of 1% wt or 0.675% volume fraction of the MWCNT in polymer composites. Also, the highest reduction in residual stresses was observed in [02/902] cross-ply laminated composite materials.

  13. Toxicity assessment of multi-walled carbon nanotubes on Cucurbita pepo L. under well-watered and water-stressed conditions.

    Science.gov (United States)

    Hatami, Mehrnaz

    2017-08-01

    The rapid increase in the production and application of various types of nanomaterials increases the possibility of their presence in total environment, which subsequently raises concerns about their potential threats to the first trophic level of organisms, specifically under varying environmental constraints. In this work, seeds of Cucurbita pepo L. were cultured in MS basal medium exposed to multi-walled carbon nanotubes (MWCNTs) at different concentrations (0, 125, 250, 500 and 1000μgmL-1) under two levels of water potential, well-watered (0MPa) and water stress (-1.5MPa) induced by polyethylene glycol (PEG 6000) for 14 days. Seeds exposed to MWCNTs showed reduction in germination percentage, root and shoot length, biomass accumulation and vigor index in a dose-dependent manner. However, seedlings germinated in MWCNTs-fortified media had significantly lower germination and growth attributes than those of control under water stress conditions. This happened due to increased oxidative injury indices including hydrogen peroxide (H2O2), and malondialdehyde (MDA) contents, as well as electrolyte leakage index (ELI) of tissues. The impaired morpho-physiological and biochemical processes of seedlings exposed to different concentrations of MWCNTs under both PEG-induced stress and non-stress growing conditions were consequence of changes in the activation of various cellular antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (POD). Taken together, our findings reveal that MWCNTs played negative role on seed germination and subsequent growth of C. pepo L. seedlings under both levels of water potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Survival of Enterococcus faecalis during alkaline stress: changes in morphology, ultrastructure, physiochemical properties of the cell wall and specific gene transcripts.

    Science.gov (United States)

    Ran, Shujun; He, Zhiyan; Liang, Jingping

    2013-11-01

    The aim of this investigation was to study the biochemical mechanisms employed by the endodontic pathogen Enterococcus faecalis to survive alkaline environment during biofilm formation. E. faecalis ATCC33186 was inoculated in media at pH 7, 9, 10 and 11 for biofilm formation. The morphology and ultrastructure of biofilm cells were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The physiochemical properties of the cell wall were investigated by measuring the hydrophobicity and Na(+)K(+)-ATPase and H(+)K(+)-ATPase activity. The expression of stress and virulence genes was quantified by real-time quantitative polymerase chain reaction. E. faecalis grown in alkaline medium developed an irregular shape and asymmetrical septation. The activity of Na(+)K(+)-ATPase increased dramatically with rising pH, whereas the activity of H(+)K(+)-ATPase exhibited no increase, except at pH 10. A marked increase in cell surface hydrophobicity was also observed with increased pH and time. In addition, transcription of most of the genes tested increased 2- to 15-fold at pH 9 or 10 compared with pH 7 and increased more than 50-fold at pH 11, which is generally recognised as nearly lethal stress. E. faecalis survival and biofilm formation under alkaline stress was unrelated to H(+)K(+)-ATPase but was correlated with an increase in Na(+)K(+)-ATPase activity and cell-surface hydrophobicity in addition to the up-regulation of genes involved in stress response and biofilm formation. These characteristics may explain why E. faecalis resists alkaline root canal medications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Stress-induced cardiomyopathy.

    Science.gov (United States)

    Boland, Torrey A; Lee, Vivien H; Bleck, Thomas P

    2015-03-01

    Reversible stress-induced cardiac dysfunction is frequently seen as a complication of a multitude of acute stress states, in particular neurologic injuries. This dysfunction may be difficult to distinguish between that caused by myocardial ischemia and may impact both the treatment strategies and prognosis of the underlying condition. Critical care practitioners should have an understanding of the epidemiology, pathophysiology, clinical characteristics, precipitating conditions, differential diagnosis, and proposed treatments for stress-induced cardiomyopathy. MEDLINE database search conducted from inception to August 2014, including the search terms "tako-tsubo," "stress-induced cardiomyopathy," "neurogenic cardiomyopathy," "neurogenic stress cardiomyopathy," and "transient left ventricular apical ballooning syndrome". In addition, references from pertinent articles were used for a secondary search. After review of peer-reviewed original scientific articles, guidelines, and reviews resulting from the literature search described above, we made final selections for included references and data based on relevance and author consensus. Stress-induced cardiomyopathy occurs most commonly in postmenopausal women. It can be precipitated by emotional stress, neurologic injury, and numerous other stress states. Patients may present with symptoms indistinguishable from acute coronary syndrome or with electrocardiogram changes and wall motion abnormalities on echocardiogram following neurologic injury. Nearly all patients will have an elevated cardiac troponin. The underlying etiology is likely related to release of catecholamines, both locally in the myocardium and in the circulation. Differential diagnosis includes myocardial infarction, myocarditis, neurogenic pulmonary edema, and nonischemic cardiomyopathy. Although the natural course of stress-induced cardiomyopathy is resolution, treatment strategies include sympathetic blockade and supportive care. Stress

  16. Oxidative stress induced modulation of platelet integrin α2bβ3 expression and shedding may predict the risk of major bleeding in heart failure patients supported by continuous flow left ventricular assist devices.

    Science.gov (United States)

    Mondal, Nandan K; Chen, Zengsheng; Trivedi, Jaimin R; Sorensen, Erik N; Pham, Si M; Slaughter, Mark S; Griffith, Bartley P; Wu, Zhongjun J

    2017-10-01

    Oxidative stress and platelet integrin α2bβ3 plays important role in the process of hemostasis and thrombosis. We hypothesized that device-induced patient specific oxidative stress and integrin α2bβ3 shedding may be linked to major bleeding complication (MBC) in heart failure (HF) patients supported by continuous flow left ventricular assist devices (CF-LVADs). We recruited 47patients implanted with CF-LVADs and 15 healthy volunteers. Fourteen patients developed MBC (bleeder group) within one month after implantation while others were considered non-bleeder group (n=33). Oxidative stresses were evaluated by measuring reactive oxygen species (ROS) in platelets, superoxide dismutase (SOD) activity, total antioxidant capacity (TAC) and oxidized low density lipoprotein (oxLDL). Assessments of α2bβ3 were carried out using flow cytometry and ELISA. Biomarkers of oxidative stress and α2bβ3 shedding (decreased surface expression and higher plasma levels) were found to be preexisting condition in all HF patients prior to CF-LVAD implantation compared to the healthy volunteers. Significantly elevated levels of ROS and oxLDL; concomitant depletion of SOD and TAC; and α2bβ3 shedding were observed in the bleeder group temporarily in comparison to the non-bleeder group after CF-LVAD implantation. A significantly strong association between α2bβ3 shedding and biomarkers of oxidative stress was observed; suggesting a potential role of oxidative stress in platelet integrin shedding leading to MBC after CF-LVAD implantation. Moreover, a receiver operating characteristic (ROC) analysis indicated that the likelihood of MBC data from Integrin α2bβ3 shedding had a predictive power of MBC in CF-LVAD patients. Oxidative stress might play a potential role in accelerating α2bβ3 shedding and platelet dysfunction, resulting in MBC in CF-LVAD patients. Integrin α2bβ3 shedding may be used to refine bleeding risk stratification in CF-LVAD patients. Copyright © 2017 Elsevier Ltd

  17. [Hypertrophic cardiomyopathy with left ventricular dilatation].

    Science.gov (United States)

    Iwami, G; Miyazaki, Y; Matsuyama, K; Shida, M; Ooga, M; Furuta, Y; Ikeda, H; Toshima, H; Chiba, M; Koga, Y

    1988-06-01

    There is increasing interest in the notion that some patients with hypertrophic cardiomyopathy (HCM) progress to morphological and functional manifestations similar to those of dilated cardiomyopathy (DCM). From 165 consecutive patients with HCM, 20 patients with left ventricular dilatation (left ventricular end-diastolic diameter greater than or equal to 50 mm) were selected and designated as dilated HCM. The diagnosis of HCM was established in these patients either by detection of the classical form of HCM in family members, with 2-dimensional echocardiographic evidence of asymmetric septal hypertrophy (ASH; septal thickness greater than or equal to 15 mm and a ratio of septal to posterior wall thickness greater than or equal to 1.3); or by demonstrating myocardial fiber disarray in autopsy or biopsy samples. The clinical manifestations of these patients with dilated HCM were then compared with those of other forms of HCM without left ventricular dilatation; 1) 40 patients with hypertrophic obstructive cardiomyopathy (HOCM) who had resting intraventricular pressure gradients of 20 mmHg or more, 2) 80 patients with non-obstructive HCM, each of whom had ASH of the entire ventricular septum (typical ASH), and 3) 25 non-obstructive patients whose hypertrophy was localized to the apical region of the ventricular septum (apical ASH). Patients having apical hypertrophy with a spade-like configuration on the left ventriculogram were excluded from the study. Compared with HOCM and typical ASH groups, the patients with dilated HCM had family histories of significantly more frequent HCM and less frequent hypertension. The patients with dilated HCM also had significantly less fractional shortening (FS), decreased interventricular septal thickness, greater left ventricular end-diastolic pressure (LVEDP), and left ventricular dilatation. During the follow-up period (average: 3.5 years), seven patients (35%) with dilated HCM died; five from congestive heart failure (CHF), one

  18. Surgical Cryoablation of Drug Resistant Ventricular Tachycardia and Aneurysmectomy of Postinfarction Left Ventricular Aneurysm

    Directory of Open Access Journals (Sweden)

    Marek Pojar

    2014-01-01

    Full Text Available Heart failure is usually associated with left ventricle remodelling, wall thickening, and worsening of the systolic function. Ventricular tachycardia is a common and a negative prognostic factor in patients with endocardial scarring following myocardial infarction and aneurysm formation. The authors present a case of a 51-year-old man with ischemic heart disease, who suffered myocardial infarction four years ago. The patient was admitted to the hospital with sustained ventricular tachycardia despite maximal pharmacotherapy and also underwent unsuccessful percutaneous radiofrequency ablation in the right ventricle. Transthoracic echocardiography revealed left ventricle dysfunction with ejection fraction of 25%, aneurysm of the apex of the left ventricle with thrombus formation inside the aneurysm. Surgical therapy consisted of the cryoablation applied at the transitional zone of the scar and viable tissue and the resection of the aneurysm. The patient remained free of any ventricular tachycardia four months later.

  19. Green walls in Vancouver

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, R. [Sharp and Diamond Landscape Architecture Inc., Vancouver, BC (Canada)

    2007-07-01

    With the renewed interest in design for microclimate control and energy conservation, many cities are implementing clean air initiatives and sustainable planning policies to mitigate the effects of urban climate and the urban heat island effect. Green roofs, sky courts and green walls must be thoughtfully designed to withstand severe conditions such as moisture stress, extremes in temperature, tropical storms and strong desiccating winds. This paper focused on the installation of green wall systems. There are 2 general types of green walls systems, namely facade greening and living walls. Green facades are trellis systems where climbing plants can grow vertically without attaching to the surface of the building. Living walls are part of a building envelope system where plants are actually planted and grown in a wall system. A modular G-SKY Green Wall Panel was installed at the Aquaquest Learning Centre at the Vancouver Aquarium in Stanley Park in September 2006. This green wall panel, which was originally developed in Japan, incorporates many innovative features in the building envelope. It provides an exterior wall covered with 8 species of plants native to the Coastal Temperate Rain Forest. The living wall is irrigated by rainwater collected from the roof, stored in an underground cistern and fed through a drip irrigation system. From a habitat perspective, the building imitates an escarpment. Installation, support systems, irrigation, replacement of modules and maintenance are included in the complete wall system. Living walls reduce the surface temperature of buildings by as much as 10 degrees C when covered with vegetation and a growing medium. The project team is anticipating LEED gold certification under the United States-Canada Green Building Council. It was concluded that this technology of vegetated building envelopes is applicable for acoustical control at airports, biofiltration of indoor air, greywater treatment, and urban agriculture and vertical

  20. Left and right ventricular diastolic function in hemodialysis patients.

    Science.gov (United States)

    Rudhani, Ibrahim Destan; Bajraktari, Gani; Kryziu, Emrush; Zylfiu, Bejtush; Sadiku, Shemsedin; Elezi, Ymer; Rexhepaj, Nehat; Vitia, Arber; Emini, Merita; Abazi, Murat; Berbatovci-Ukimeraj, M; Kryeziu, Kaltrina; Hsanagjekaj, Venera; Korca, Hajrije; Ukimeri, Aferdita

    2010-11-01

    The aim of this prospective study was the assessment of left ventricular and right ventricular diastolic function in patients on hemodialysis (HD) and the correlation of this function with the duration of HD. The study included 42 patients (22 females and 20 males) with chronic renal failure (CRF), treated with HD, and 40 healthy subjects (24 females and 16 males) with no history of cardiovascular disease and with normal renal function, who constituted the control group. The groups were matched for age and sex. All study patients and control subjects underwent detailed history taking and physical examination. They also underwent electrocardiogram, echocardiography and biochemical and hematological blood analyses. Significant differences were noted between the two groups in the two-dimensional and M-mode echocardiography findings concerning aortic root dimension, transverse diameter of the left atrium, thickness of the interventricular septum, thickness of the left ventricular posterior wall, left ventricular diastolic diameter, left ventricular systolic diameter, shortening fraction, ejection fraction as well as findings from the pulse Doppler study, including E wave, A wave, E/A ratio, deceleration time of E wave (DT-E), acceleration time of E wave (AT-E), tricuspid E and A waves (E tr and A tr ) and E tr /A tr , ratio. There were significant changes in HD patients without arterial hypertension as well in the control group subjects. Our study suggests that the left ventricular and left atrial dimensions as well as the left ventricular wall thickness are augmented in patients with CRF treated with HD compared with the control group. Additionally, the left and right ventricular diastolic function is also reduced in these patients. These differences were also noted in patients with CRF without arterial hypertension. Left ventricular diastolic dysfunction had no correlation with the duration of HD.

  1. MRI assessment of right ventricular dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Di Cesare, Ernesto [Department of Radiology, University of L' Aquila, via Vetoio 1, 67100, L' Aquila (Italy)

    2003-06-01

    Right ventricular dysplasia is a new entity of unknown origin in the classification of cardiomyopathies. Also known as arrhythmogenic right ventricular cardiomyopathy (ARVC) or arrhythmogenic right ventricular dysplasia, it is a disease of the heart muscle characterised by fibroadipose atrophy mainly involving the right ventricle and responsible for severe ventricular arrhythmias and sudden death also in young people. Magnetic resonance imaging provides evidence of ventricular dilatation at the outflow tract, thinning and thickening of the wall, diastolic bulging areas (especially located at the level of the right ventricle outflow tract) and fatty substitution of the myocardium mainly at the level of the right ventricle. Many radiologists erroneously consider the previously described fatty substitution as the main sign of ARVC, even though an evaluation of fat substitution alone may be a source of error for two reasons: firstly, because isolated areas of fatty replacement are not synonymous with ARVC since small non-transmural focal fatty areas of fat are also present in the normal patients; and secondly, because the MRI detection of fat may be overestimated due to partial-volume artefacts with normal subepicardial fat. Cardiac MRI can also be employed for the diagnosis of idiopathic right ventricular outflow tract tachycardia. Considering the evolutive nature of the disease, the non-invasiveness of MRI allows the follow-up of these patients and may be considered an excellent screening modality for the diagnosis of ARVC in family members. Finally, MRI can be employed in electrophysiological studies to locate the arrhythmogenic focus and reduce sampling errors. (orig.)

  2. Phase-Contrast MRI measurements in intra-cranial aneurysms in-vivo of flow patterns, velocity fields and wall shear stress: A comparison with CFD

    Science.gov (United States)

    Boussel, Loic; Rayz, Vitaliy; Martin, Alastair; Acevedo-Bolton, Gabriel; Lawton, Michael T.; Higashida, Randall; Smith, Wade S.; Young, William L.; Saloner, David

    2010-01-01

    Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as Wall Shear Stress (WSS) and Maximum Shear Stress (MSS). Estimation of these parameters can be performed using numerical simulations (computational fluid dynamics - CFD) but can also be directly measured with MRI using a time-dependent 3D phase-contrast sequence with encoding of each of the three components of the velocity vectors (7D-MRV). In order to study the accuracy of 7D-MRV in estimating these parameters in–vivo, in comparison with CFD, 7D-MRV and patient-specific CFD modeling was performed for three patients who had intracranial aneurysms. A visual and a quantitative analysis of the flow pattern and the distribution of velocities, MSS, and WSS were performed between the two techniques. Spearman's coefficients of correlation between the two techniques were 0.56 for the velocity field, 0.48 for MSS and 0.59 for WSS. Visual analysis and Bland-Altman plots showed a good agreement for flow pattern and velocities but large discrepancies for MSS and WSS. In conclusion, these results indicate that in-vivo 7D-MRV can be used to measure velocity flow fields and to estimate MSS and WSS but is not currently able to provide accurate quantification of these two last parameters. PMID:19161132

  3. Candida albicans response regulator gene SSK1 regulates a subset of genes whose functions are associated with cell wall biosynthesis and adaptation to oxidative stress.

    Science.gov (United States)

    Chauhan, Neeraj; Inglis, Diane; Roman, Elvira; Pla, Jesus; Li, Dongmei; Calera, Jose A; Calderone, Richard

    2003-10-01

    Ssk1p of Candida albicans is a putative response regulator protein of the Hog1 two-component signal transduction system. In Saccharomyces cerevisiae, the phosphorylation state of Ssk1p determines whether genes that promote the adaptation of cells to osmotic stress are activated. We have previously shown that C. albicans SSK1 does not complement the ssk1 mutant of S. cerevisiae and that the ssk1 mutant of C. albicans is not sensitive to sorbitol. In this study, we show that the C. albicans ssk1 mutant is sensitive to several oxidants, including hydrogen peroxide, t-butyl hydroperoxide, menadione, and potassium superoxide when each is incorporated in yeast extract-peptone-dextrose (YPD) agar medium. We used DNA microarrays to identify genes whose regulation is affected by the ssk1 mutation. RNA from mutant cells (strain CSSK21) grown in YPD medium for 3 h at 30 degrees C was reverse transcribed and then compared with similarly prepared RNA from wild-type cells (CAF2). We observed seven genes from mutant cells that were consistently up regulated (three-fold or greater compared to CAF2). In S. cerevisiae, three (AHP1, HSP12, and PYC2) of the seven genes that were up regulated provide cells with an adaptation function in response to oxidative stress; another gene (GPH1) is regulated under stress conditions by Hog1p. Three other genes that are up regulated encode a cell surface protein (FLO1), a mannosyl transferase (MNN4-4), and a putative two-component histidine kinase (CHK1) that regulates cell wall biosynthesis in C. albicans. Of the down-regulated genes, ALS1 is a known cell adhesin in C. albicans. Verification of the microarray data was obtained by reverse transcription-PCR for HSP12, AHP1, CHK1, PYC2, GPH1, ALS1, MNN4-4, and FLO1. To further determine the function of Ssk1p in the Hog1p signal transduction pathway in C. albicans, we used Western blot analysis to measure phosphorylation of Hog1p in the ssk1 mutant of C. albicans when grown under either osmotic or

  4. Left Ventricular Hypertrophy

    Science.gov (United States)

    ... need to restrict certain physical activities, such as weightlifting, which may temporarily raise your blood pressure. The ... Accessed April 6, 2015. Chatterjee S, et al. Meta-analysis of left ventricular hypertrophy and sustained arrhythmias. American ...

  5. Premature Ventricular Contractions (PVCs)

    Science.gov (United States)

    ... Premature ventricular contractions (PVCs) Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  6. Right ventricular dysfunction affects survival after surgical left ventricular restoration.

    Science.gov (United States)

    Couperus, Lotte E; Delgado, Victoria; Palmen, Meindert; van Vessem, Marieke E; Braun, Jerry; Fiocco, Marta; Tops, Laurens F; Verwey, Harriëtte F; Klautz, Robert J M; Schalij, Martin J; Beeres, Saskia L M A

    2017-04-01

    Several clinical and left ventricular parameters have been associated with prognosis after surgical left ventricular restoration in patients with ischemic heart failure. The aim of this study was to determine the prognostic value of right ventricular function. A total of 139 patients with ischemic heart failure (62 ± 10 years; 79% were male; left ventricular ejection fraction 27% ± 7%) underwent surgical left ventricular restoration. Biventricular function was assessed with echocardiography before surgery. The independent association between all-cause mortality and right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain was assessed. The additive effect of multiple impaired right ventricular parameters on mortality also was assessed. Baseline right ventricular fractional area change was 42% ± 9%, tricuspid annular plane systolic excursion was 18 ± 3 mm, and right ventricular longitudinal peak systolic strain was -24% ± 7%. Within 30 days after surgery, 15 patients died. Right ventricular fractional area change (hazard ratio, 0.93; 95% confidence interval, 0.88-0.98; P right ventricular longitudinal peak systolic strain (hazard ratio, 1.15; 95% confidence interval, 1.05-1.26; P Right ventricular function was impaired in 21%, 20%, and 27% of patients on the basis of right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain, respectively. Any echocardiographic parameter of right ventricular dysfunction was present in 39% of patients. The coexistence of several impaired right ventricular parameters per patient was independently associated with increased 30-day mortality (hazard ratio, 2.83; 95% confidence interval, 1.64-4.87, P right ventricular systolic dysfunction is independently associated with increased mortality in patients with ischemic heart failure undergoing surgical left

  7. [Stress echo and valvular heart disease].

    Science.gov (United States)

    Monin, J L

    2005-06-01

    Stress echo has already been validated in some forms of valvular heart disease, especially in calcific aortic stenosis with low cardiac output and dynamic mitral regurgitation (MR) of valvular heart disease. Stress Doppler haemodynamics is a term used to differentiate these new indications from that of segmental wall analysis of the left atrium in ischaemic heart disease. In calcific aortic stenosis with low output, the haemodynamics with low dose dobutamine allows assessment of the real severity of the aortic stenosis and identification of the rare cases with mild stenosis: the principal indication remains the assessment of operative risk and long-term prognosis by the study of left ventricular contractile reserve. In cases of ischaemic left ventricular systolic dysfunction, the presence of mild mitral regurgitation (regurgitant surface area >20 mm2 at rest) is a poor prognostic factor. The dynamic character of mitral regurgitation is related to left ventricular remodelling which leads to deformation of the valvular apparatus (mitral tenting). Dynamic mitral regurgitation (regurgitant orifice area >13 mm2 on exercise) is a powerful prognostic factor, the role of which has recently been demonstrated in the genesis of acute pulmonary oedema. the other indications of stress haemodynamics are under validation, mainly the assessment of exercise capacity and valvular compliance in mitral stenosis or asymptomatic aortic stenosis.

  8. In vivo monitoring of oxidative burst on aloe under salinity stress using hemoglobin and single-walled carbon nanotubes modified carbon fiber ultramicroelectrode.

    Science.gov (United States)

    Ren, Qiong-Qiong; Yuan, Xiao-Jun; Huang, Xiao-Rong; Wen, Wei; Zhao, Yuan-Di; Chen, Wei

    2013-12-15

    Single-walled carbon nanotubes (SWCNTs) and hemoglobin (Hb) modified carbon fiber ultramicroelectrode (CFUME) were employed to construct a direct electron transfer based in vivo H2O2 sensor. At the low working potential of -0.1 V, Hb/SWCNTs/CFUME showed a dynamic range up to 0.405 mM with a low detection limit of 4 μM (S/N=3) and a high sensitivity of 1.07 log(A) log(M)(-1) cm(-2). The apparent Michaelis-Menten constant (Km, app) was estimated to be as low as 1.35 mM. Due to the extremely small dimension and low working potential, Hb/SWCNTs/CFUME could give directly amperometric in vivo monitoring of H2O2 in aloe leaves with salt stress for 19.5h without the requirement of complex data processing and extra surface coatings to avoid interferences. The sharp increase of H2O2 level in aloe leaves with salt stress was clearly observed using Hb/SWCNTs/CFUME from 12.5 h, while in the aloe without salt stress, H2O2 level remained stable in the whole measurement. For further confirming the in vivo response of Hb/SWCNTs/CFUME, catalase (CAT) was injected into the spot adjacent to the sensor and caused rapid current decrease, which suggests the scavenging of H2O2. These results indicate that Hb/SWCNTs/CFUME can be a powerful tool for in vivo investigation of ROS. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Transcriptome analysis of WRKY gene family in Oryza officinalis Wall ex Watt and WRKY genes involved in responses to Xanthomonas oryzae pv. oryzae stress.

    Science.gov (United States)

    Jiang, Chunmiao; Shen, Qingxi J; Wang, Bo; He, Bin; Xiao, Suqin; Chen, Ling; Yu, Tengqiong; Ke, Xue; Zhong, Qiaofang; Fu, Jian; Chen, Yue; Wang, Lingxian; Yin, Fuyou; Zhang, Dunyu; Ghidan, Walid; Huang, Xingqi; Cheng, Zaiquan

    2017-01-01

    Oryza officinalis Wall ex Watt, a very important and special wild rice species, shows abundant genetic diversity and disease resistance features, especially high resistance to bacterial blight. The molecular mechanisms of bacterial blight resistance in O. officinalis have not yet been elucidated. The WRKY transcription factor family is one of the largest gene families involved in plant growth, development and stress response. However, little is known about the numbers, structure, molecular phylogenetics, and expression of the WRKY genes under Xanthomonas oryzae pv. oryzae (Xoo) stress in O. officinalis due to lacking of O. officinalis genome. Therefore, based on the RNA-sequencing data of O. officinalis, we performed a comprehensive study of WRKY genes in O. officinalis and identified 89 OoWRKY genes. Then 89 OoWRKY genes were classified into three groups based on the WRKY domains and zinc finger motifs. Phylogenetic analysis strongly supported that the evolution of OoWRKY genes were consistent with previous studies of WRKYs, and subgroup IIc OoWRKY genes were the original ancestors of some group II and group III OoWRKYs. Among the 89 OoWRKY genes, eight OoWRKYs displayed significantly different expression (>2-fold, pWRKY family of transcription factors in O.officinalis. Insight was gained into the classification, evolution, and function of the OoWRKY genes, revealing the putative roles of eight significantly different expression OoWRKYs in Xoo strains PXO99 and C5 stress responses in O.officinalis. This study provided a better understanding of the evolution and functions of O. officinalis WRKY genes, and suggested that manipulating eight significantly different expression OoWRKYs would enhance resistance to bacterial blight.

  10. Ventricular myocardial architecture in marine fishes.

    Science.gov (United States)

    Sanchez-Quintana, D; Hurle, J M

    1987-03-01

    The fiber architecture of the ventricular myocardium has been studied in elasmobranch (Isurus oxyrhinchus, Galeorhinus galeus, Prionace glauca) and teleost (Xiphias gladius, Thunnus thynnus, Thunnus alalunga) fish species with hearts displaying mixed types of ventricular musculature (compact and trabecular). In all cases, the compact myocardium is organized in layers of fiber bundles with an orderly arrangement within the ventricular walls. The number of these layers appears to be dependent on the relative thickness of the compact myocardium. Differences in the pattern of myocardial fiber arrangement were observed among the different fish species. In elasmobranchs the compact myocardium at the level of the atrioventricular orifice is continuous with the trabeculated myocardium. Furthermore, in elasmobranchs the trabeculated myocardium displays a precise arrangement in arcuate trabeculae running from the auriculoventricular to the conoventricular orifices. In teleosts, the compact myocardium is independent of the trabeculated myocardium and a large number of fibers insert into the bulboventricular fibrous ring. The trabeculated myocardium in these species displays an anarchic arrangement except at the level of the bulboventricular orifice, where the fibers tend to be aligned longitudinally, also being inserted into the fibrous ring. Minor differences, consisting mainly of the presence of extra bundles of fibers, were also observed among different individuals of the same species. The possible relationship between myocardial fiber architecture and ventricular shape is discussed.

  11. [Ventricular pump function under ectopic excitation of the frog heart].

    Science.gov (United States)

    Kibler, N A; Belogolova, A S; Vaĭkshnoraĭte, M A; Azarov, Ia E; Shmakov, D N

    2008-02-01

    The ventricular pump function under ectopic excitation of the heart was studied in decapitated and pithed adult frogs Rana temporaria (n = 21) at 18-19 degrees C. The intraventricular pressure was recorded with a catheter via ventricular wall. During pacing of the ventricular base and apex, the systolic pressure decreased (6.1 +/- 4.5 mm Hg and 8.9 +/- 5.0 mm Hg, respectively) as compared to the supraventricular rhythm (8.9 +/- 5.0 mm Hg, p < 0.05). The end-diastolic pressure decreased insignificantly both under basal and apical pacing. The systolic rate of pressure rise during dP/dtmax decreased under ventricular pacing, especially during pacing of the ventricular apex, as compared to the supraventricular rhythm (14.4 +/- 6/9 mm Hg/s and 22.1 +/- 11.2 mm Hg/s, respectively, p < 0.003). The isovolumetric relaxation (dP/dtmin) slowed during apical pacing as compared to the supraventricular rhythm (-25.1 +/- 13.6 and -35.6 +/- 18.3 mm Hg/s, respectively, p < 0.03). Ectopic excitation of the ventricular base and apex resulted in increase of the QRS duration (93 +/- 33 ms and 81 +/- 30 ms, respectively) as compared to the supraventricular rhythm (63 +/- 13 ms, p < 0.05). Thus, pacing of different ventricular areas ventricular myocardium with the ventricular pump function being reduced more obviously during the apical pacing compared to the pacing of ventricular base.

  12. Large-scale proteomic analysis of the grapevine leaf apoplastic fluid reveals mainly stress-related proteins and cell wall modifying enzymes.

    Science.gov (United States)

    Delaunois, Bertrand; Colby, Thomas; Belloy, Nicolas; Conreux, Alexandra; Harzen, Anne; Baillieul, Fabienne; Clément, Christophe; Schmidt, Jürgen; Jeandet, Philippe; Cordelier, Sylvain

    2013-02-08

    The extracellular space or apoplast forms a path through the whole plant and acts as an interface with the environment. The apoplast is composed of plant cell wall and space within which apoplastic fluid provides a means of delivering molecules and facilitates intercellular communications. However, the apoplastic fluid extraction from in planta systems remains challenging and this is particularly true for grapevine (Vitis vinifera L.), a worldwide-cultivated fruit plant. Large-scale proteomic analysis reveals the protein content of the grapevine leaf apoplastic fluid and the free interactive proteome map considerably facilitates the study of the grapevine proteome. To obtain a snapshot of the grapevine apoplastic fluid proteome, a vacuum-infiltration-centrifugation method was optimized to collect the apoplastic fluid from non-challenged grapevine leaves. Soluble apoplastic protein patterns were then compared to whole leaf soluble protein profiles by 2D-PAGE analyses. Subsequent MALDI-TOF/TOF mass spectrometry of tryptically digested protein spots was used to identify proteins. This large-scale proteomic analysis established a well-defined proteomic map of whole leaf and leaf apoplastic soluble proteins, with 223 and 177 analyzed spots, respectively. All data arising from proteomic, MS and MS/MS analyses were deposited in the public database world-2DPAGE. Prediction tools revealed a high proportion of (i) classical secreted proteins but also of non-classical secreted proteins namely Leaderless Secreted Proteins (LSPs) in the apoplastic protein content and (ii) proteins potentially involved in stress reactions and/or in cell wall metabolism. This approach provides free online interactive reference maps annotating a large number of soluble proteins of the whole leaf and the apoplastic fluid of grapevine leaf. To our knowledge, this is the first detailed proteome study of grapevine apoplastic fluid providing a comprehensive overview of the most abundant proteins

  13. Ventricular perforation by pacemaker lead repaired with two hemostatic devices.

    Science.gov (United States)

    Prestipino, Filippo; Nenna, Antonio; Casacalenda, Adele; Chello, Massimo

    2014-01-01

    Cardiac perforation is a rare, but potentially serious, complication of pacemaker implantation that may develop days or weeks after implantation. In the current case, 92-year-old man underwent permanent pacemaker implantation, but he presented 3 weeks later with severe symptoms. Computed tomography showed protrusion of the tip of the ventricular electrode through the right ventricle and into the chest wall. During an urgent surgical intervention, the lead was disconnected and extracted. A sealing hemostatic device and an hemostatic patch were applied to repair the ventricle; the procedure was uneventfull. This case demonstrates how the correct diagnosis of ventricular perforation is crucial, and should be followed immediately by surgical planning. The hemostatic patch is a valuable alternative to sutures in patients with thin and fragile ventricular wall, unable to undergo stitching. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Quantitative assessment of regional left ventricular motion using endocardial landmarks

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); T.E.H. Hooghoudt (Ton); P.W.J.C. Serruys (Patrick); J.C.H. Schuurbiers (Johan); J.H.C. Reiber (Johan); G.T. Meester (Geert); P.D. Verdouw (Pieter); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractIn this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the

  15. Ruptura da parede livre do ventrículo direito após infarto do miocárdio Rupture of the right ventricular free wall after myocardial infarction

    Directory of Open Access Journals (Sweden)

    Rômulo César Arnal Bonini

    2012-03-01

    Full Text Available Paciente de 75 anos, com ruptura da parede livre do ventrículo direito, corrigida com pontos de prolene 3.0 ancorados em tira de pericárdio bovino, promovendo o fechamento da ruptura. O paciente recebeu alta hospitalar no 59º dia de pós-operatório, em boas condições clínicas e laboratoriais.Patient 75, years-old, with free wall rupture of the right ventricle, corrected with prolene 3.0 points anchored in bovine pericardium patch, promoting the closure of the rupture. The patient was discharged on the 59th day after surgery in good clinical ans laboratorial conditions.

  16. Cell wall proteomics of crops

    Directory of Open Access Journals (Sweden)

    Setsuko eKomatsu

    2013-02-01

    Full Text Available Cell wall proteins play key roles in cell structure and metabolism, cell enlargement, signal transduction, responses to environmental stress, and many other physiological events. Agricultural crops are often used for investigating stress tolerance because cultivars with differing degrees of tolerance are available. Abiotic and biotic stress factors markedly influence the geographical distribution and yields of many crop species. Crop cell wall proteomics is of particular importance for improving crop productivity, particularly under unfavorable environmental conditions. To better understand the mechanisms underlying stress response in crops, cell wall proteomic analyses are being increasingly utilized. In this review, the methods of purification and purity assays of cell wall protein fractions from crops are described, and the results of protein identification using gel-based and gel-free proteomic techniques are presented. Furthermore, protein composition of the cell walls of rice, wheat, maize and soybean are compared, and the role of cell wall proteins in crops under flooding and drought stress is discussed. This review will be useful for clarifying the role of the cell wall of crops in response to environmental stresses.

  17. Risk Factors for Asymptomatic Ventricular Dysfunction in Rheumatoid Arthritis Patients

    Science.gov (United States)

    Garza-García, Carlos; Rocío, Sánchez-Santillán; Orea-Tejeda, Arturo; Castillo-Martínez, Lilia; Eduardo, Canseco; López-Campos, José Luis; Keirns-Davis, Candace

    2013-01-01

    Objective. The aim of the study was to describe echocardiographic abnormalities in patients with rheumatoid arthritis, concurrent systemic comorbidities, rheumatologic clinical activity, serologic markers of rheumatoid arthritis, and inflammatory activity. Methods. In an observational, cross-sectional study, rheumatoid arthritis outpatients were included (n = 105). Conventional transthoracic echocardiographic variables were compared between patients with arthritis and non-RA controls (n = 41). For rheumatoid arthritis patients, articular activity and rheumatologic and inflammatory markers were obtained. Results. Ventricular dysfunction was found in 54.3% of the population: systolic (18.1%), diastolic (32.4%), and/or right (24.8%), with lower ejection fraction (P < 0.0001). Pulmonary hypertension was found in 46.9%. Other echocardiographic findings included increased left atrial diameter (P = 0.01), aortic diameter (P = 0.01), ventricular septum (P = 0.01), left ventricular posterior wall (P = 0.013), and right ventricular (P = 0.01) and atrial diameters compared to control subjects. Rheumatoid factor and anti-CCP antibodies levels were significantly elevated in cases with ventricular dysfunction. Angina and myocardial infarction, diabetes, and dyslipidemia were the main risk factors for ventricular dysfunction. Conclusions. Ventricular dysfunction is common in rheumatoid arthritis and associated with longer disease duration and increased serologic markers of rheumatoid arthritis. Screening for cardiac abnormalities should be considered in this kind of patients. PMID:24368945

  18. L-Arginine ameliorates cardiac left ventricular oxidative stress by upregulating eNOS and Nrf2 target genes in alloxan-induced hyperglycemic rats

    Energy Technology Data Exchange (ETDEWEB)

    Ramprasath, Tharmarajan; Hamenth Kumar, Palani; Syed Mohamed Puhari, Shanavas; Senthil Murugan, Ponniah; Vasudevan, Varadaraj [Molecular Cardiology Unit, Department of Biochemistry, Center for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, Tamilnadu (India); Selvam, Govindan Sadasivam, E-mail: drselvamgsbiochem@rediffmail.com [Molecular Cardiology Unit, Department of Biochemistry, Center for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, Tamilnadu (India)

    2012-11-23

    Highlights: Black-Right-Pointing-Pointer L-Arginine treatment reduced the metabolic disturbances in diabetic animals. Black-Right-Pointing-Pointer Antioxidant marker proteins were found high in myocardium by L-arginine treatment. Black-Right-Pointing-Pointer Elevated antioxidant status, mediates the reduced TBA-reactivity in left ventricle. Black-Right-Pointing-Pointer L-Arginine treatment enhanced the Nrf2 and eNOS signaling in left ventricle. Black-Right-Pointing-Pointer Improved cell survival signaling by arginine, offers a novel tactic for targeting. -- Abstract: Hyperglycemia is independently related with excessive morbidity and mortality in cardiovascular disorders. L-Arginine-nitric oxide (NO) pathway and the involvement of NO in modulating nuclear factor-E2-related factor-2 (Nrf2) signaling were well established. In the present study we investigated, whether L-arginine supplementation would improve the myocardial antioxidant defense under hyperglycemia through activation of Nrf2 signaling. Diabetes was induced by alloxan monohydrate (90 mg kg{sup -1} body weight) in rats. Both non-diabetic and diabetic group of rats were divided into three subgroups and they were administered either with L-arginine (2.25%) or L-NAME (0.01%) in drinking water for 12 days. Results showed that L-arginine treatment reduced the metabolic disturbances in diabetic rats. Antioxidant enzymes and glutathione levels were found to be increased in heart left ventricles, thereby reduction of lipid peroxidation by L-arginine treatment. Heart histopathological analysis further validates the reversal of typical diabetic characteristics consisting of alterations in myofibers and myofibrillary degeneration. qRT-PCR studies revealed that L-arginine treatment upregulated the transcription of Akt and downregulated NF-{kappa}B. Notably, transcription of eNOS and Nrf2 target genes was also upregulated, which were accompanied by enhanced expression of Nrf2 in left ventricular tissue from diabetic

  19. 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, ...

  20. Predictors of the left ventricular dysfunction induced by ventricular arrhythmia

    Directory of Open Access Journals (Sweden)

    А. І. Vytryhovskiy

    2016-08-01

    Full Text Available The most powerful predictor of life-threatening arrhythmia risk is a combination of low heart rate variability with low ejection fraction (EF of the left ventricle. Aim. To identify predictors of left ventricle dysfunction which is induced by ventricular arrhythmia. Materials and methods. To diagnose structural changes of left ventricular functional capacity and reserves in patients with previous myocardial infarction and patients with high and very high cardiovascular risk by SCORE scale and for establishment the relationship between morphological heart changes and pathological phenomenon of heart turbulence echocardiography and study of heart rate turbulence variability were performed. 603 patients were selected for the research. All patients were divided into groups: group 1 – patients with coronary heart disease, but without associated risk factors, such as smoking, obesity, metabolic syndrome; group 2 – patients who smoke tobacco more than 2 years (very high cardiovascular risk by scale SCORE; group 3 – patients with metabolic syndrome without coronary heart disease or arterial hypertension (very high cardiovascular risk by scale SCORE. The control group consisted of 149 persons. Results. The feature of structural changes in patients with myocardial infarction and in patients with a high cardiovascular risk by SCORE with heart rate turbulence compared with cases without НRT is considerably thickening of the left interventricular septum in systole. Based on this, it can be argued that the emergence of ventricular arrhythmia and accordingly phenomenon of heart rate turbulence in patients with existing cardiovascular diseases and risk factors has both morphological and functional character. Significant difference of echocardioscopy parameters in patients with postinfarction cardiosclerosis and risk factors by the SCORE system was established by index of intraventricular septum thickness in systole, and in persons with high risk – in

  1. Tomato (Lycopersicon esculentum) Supplementation Induces Changes in Cardiac miRNA Expression, Reduces Oxidative Stress and Left Ventricular Mass, and Improves Diastolic Function.

    Science.gov (United States)

    Pereira, Bruna L B; Arruda, Fernanda C O; Reis, Patrícia P; Felix, Tainara F; Santos, Priscila P; Rafacho, Bruna P; Gonçalves, Andrea F; Claro, Renan T; Azevedo, Paula S; Polegato, Bertha F; Okoshi, Katashi; Fernandes, Ana A H; Paiva, Sergio A R; Zornoff, Leonardo A M; Minicucci, Marcos F

    2015-11-19

    The aim of this study was to evaluate the effects of tomato supplementation on the normal rat heart and the role of oxidative stress in this scenario. Male Wistar rats were assigned to two groups: a control group (C; n = 16), in which animals received a control diet + 0.5 mL of corn oil/kg body weight/day, and a tomato group (T; n = 16), in which animals received a control diet supplemented with tomato +0.5 mL of corn oil/kg body weight/day. After three months, morphological, functional, and biochemical analyses were performed. Animals supplemented with tomato had a smaller left atrium diameter and myocyte cross-sectional area (CSA) compared to the control group (C group: 474 (415-539); T group: 273 (258-297) µm²; p = 0.004). Diastolic function was improved in rats supplemented with tomato. In addition, lipid hydroperoxide was lower (C group: 267 ± 46.7; T group: 219 ± 23.0 nmol/g; p = 0.039) in the myocardium of rats supplemented with tomato. Tomato intake was also associated with up-regulation of miR-107 and miR-486 and down-regulation of miR-350 and miR-872. In conclusion, tomato supplementation induces changes in miRNA expression and reduces oxidative stress. In addition, these alterations may be responsible for CSA reduction and diastolic function improvement.

  2. Impact on left ventricular function of the exercise response of coronary collateral flow in coronary heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Tweddel, A.C.; Martin, W.; McGhie, I.; Hutton, I.

    1985-05-01

    This study was designed to determine the effect of physiological stress on regional myocardial flow, and the effect of collateral circulation on left ventricular function. Myocardial flow was measured by the Xenon clearance technique in 25 patients with stable angina, studied at routine coronary angiography, with normal distribution of flow obtained from 10 patients. Regional wall motion was quantified from the contrast ventriculogram by percentage shortening of radial chords. Twenty collateral distributions were identified angiographically and a further 14 with intracoronary Xenon. Scans were performed at rest and immediately post maximal supine exercise. Collateral flows in response to dynamic exercise were differentiated as follows: in 8 regions identified arteriographically, mean flow fell from 46.3 +- 5.1 to 40 +- 5.1 ml/100g/min (p<0.02) and from 28.9 +- 3.6 to 21.1 +- 1.4 ml/100g/min (p<0.05) in regions of collateral flow seen with Xenon. In these regions, mean left ventricular percentage shortening was 22 +- 6.0% and 35.5 +- 5.0% respectively. In contrast, in 12 regions demonstrated angiographically, collateral flow increased 41.2 +- 4.6 to 63.4 +- 5.8 ml/100g/min (p<0.005), and 6 Xenon collateral distributions where flow increased post exercise from 19.5 +- 7.8 to 37.8 +- 5.1 ml/100g/min (p<0.05). The mean left ventricular percentage shortening was 43.2 +- 7.3% (p<0.02) in these collateral distributions identified arteriographically and 44 +- 4.5% (p<0.05) with Xenon. The authors conclude that collateral flow, which increased in response to stress, appears to be beneficial in the preservation of regional left ventricular function.

  3. 3D axial and circumferential wall shear stress from 4D flow MRI data using a finite element method and a laplacian approach.

    Science.gov (United States)

    Sotelo, Julio; Dux-Santoy, Lydia; Guala, Andrea; Rodríguez-Palomares, José; Evangelista, Arturo; Sing-Long, Carlos; Urbina, Jesús; Mura, Joaquín; Hurtado, Daniel E; Uribe, Sergio

    2017-10-04

    To decompose the 3D wall shear stress (WSS) vector field into its axial (WSSA ) and circumferential (WSSC ) components using a Laplacian finite element approach. We validated our method with in silico experiments involving different geometries and a modified Poiseuille flow. We computed 3D maps of the WSS, WSSA , and WSSC using 4D flow MRI data obtained from 10 volunteers and 10 patients with bicuspid aortic valve (BAV). We compared our method with the centerline method. The mean value, standard deviation, root mean-squared error, and Wilcoxon signed rank test are reported. We obtained an error method and the modified Poiseuille flow for the WSS, WSSA , and WSSC . We found statistically significance differences between our method and a 3D centerline method. In BAV patients, we found a 220% significant increase in the WSSC in the ascending aorta with respect to volunteers. We developed a novel methodology to decompose the WSS vector in WSSA and WSSC in 3D domains, using 4D flow MRI data. Our method provides a more robust quantification of WSSA and WSSC in comparison with other reported methods. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  4. 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.

  5. Ultrasonic Thickness of Lateral Abdominal Wall Muscles in Response to Pelvic Floor Muscle Contraction in women with stress incontinency with and without Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    Farideh Dehghan-Manshadi

    2014-01-01

    Full Text Available Objective: Urinary Incontinence (UI as a common lower urinary tract dysfunction , results from Pelvic Floor Muscle's (PFM underactivity.Because of co-activation of PFM and the Lateral Abdominal Wall Muscles (LAWM, this study was aimed to investigate the changes in the ultrasonic thickness of the LAWM in response to PFM contraction in stress urinary incontinent (SUIwomen with and without Chronic Low Back Pain (CLBP. Materials & Methods: A total of 28 women, 10 healthy, 18 SUI with and without CLBP (9 in each group participated in this quasi-experimental study. After collecting demographic information and assessment of PFM function, changes in ultrasonic thickness of right LAWM were measured in response to PFM contraction. One way ANOVA, Kruskal-Wallis and Pearson’s correlation tests were performed to analyze the data. Values of P0.05. There was a significant increase in thickness of the Traversus Abdominis Muscle (TrA during PFM contraction in control group comparing experimental groups (P=0.03. Women in control group showed significantly higher PFM strength and more intravaginal pressure (P=0.001. Conclusion: Changes in ultrasonic thickness of the TrA during PFM contraction revealed disturbance of co-activation of the LAWM and the PFM in women with and without SUI CLBP.

  6. Niacin ameliorates kidney warm ischemia and reperfusion injury-induced ventricular dysfunction and oxidative stress and disturbance in mitochondrial metabolism in rats.

    Science.gov (United States)

    Tai, S T; Fu, Y H; Yang, Y C; Wang, J J

    2015-05-01

    Kidney ischemia and reperfusion (I/R) injury-associated acute and chronic kidney injury often leads to cardiac dysfunction, which may involve depletion of intracellular NAD(+) (the oxidized form of the nicotinamide adenine dinucleotide coenzyme) and reduction in intracellular adenosine triphosphate (ATP) levels, resulting in mitochondrial dysfunction. We examined whether treatment with niacin, an antioxidant and a component of NAD+, protects cardiac function and improves myocardial mitochondrial metabolism during kidney I/R injury. Studies were performed in Sprague-Dawley male rats divided into sham-operated, kidney I/R, and niacin-treated kidney I/R groups. Niacin was administered 3 days before the ischemia through 7 days of reperfusion. Kidney ischemia was conducted by bilateral occlusion of renal pedicles for 45 minutes, followed by releasing the clamps and closing the abdominal incision. After 7 days of reperfusion, we measured the cardiac function using a simultaneous pressure-volume catheter, cardiac biomarker (troponin T; cTnT), and kidney injury marker (creatinine and blood urea nitrogen). Myocardial malondialdehyde level and peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α mRNA expression also were measured. Kidney I/R injury impairs cardiac function, induces myocardial and kidney injury, and markedly increases myocardial PGC-1α mRNA expression, suggesting utilizing more free fatty acid for ATP production. Niacin treatment improved cardiac function, reduced oxidative stress, and sustained PGC-1α expression (P Niacin improves mitochondrial metabolism and reduced myocardial oxidative stress. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Left ventricular scar impact on left ventricular synchronization parameters and outcomes of cardiac resynchronization therapy.

    Science.gov (United States)

    Ahmed, Walid; Samy, Wael; Tayeh, Osama; Behairy, Noha; Abd El Fattah, Alia

    2016-11-01

    Left ventricular scar, including global scar and lateral wall, plays an important role in predicting response to cardiac resynchronization therapy (CRT). Thirty patients underwent CRT implantation. Assessment of left ventricular (LV) dyssynchrony was done through Gated SPECT LV phase analysis. Pre-implantation cardiac magnetic resonance (CMR) with late gadolinium enhancement technique to examine LV scar burden. Echocardiographic examination of LV end-systolic volume (LVES) prior to CRT and 6 months later. Thirty patients received CRT (mean age 58.7±9.0, 24 males). Reverse LV remodeling (decline ≥15% from baseline VES) was documented in 19 patients. Temporal changes in LV dyssynchrony parameters were correlated to LV reverse remodeling. Applying ROC for predicting CRT non-response showed a cutoff 36.5% of global LV scar burden had a sensitivity of 81.8% and specificity of 68.4%. A cutoff for lateral wall scar burden 40.5% of whole lateral wall had a sensitivity of 72.7% and specificity of 68.4%. Reverse LV remodeling is associated with temporal improvements in LV dyssynchrony parameters. LV scar had an unfavorable impact on CRT response. Both global and lateral wall scar burden could predict CRT nonresponse status. Copyright © 2016. Published by Elsevier Ireland Ltd.

  8. Ventricular dysfunction in children with obstructive sleep apnea: radionuclide assessment

    Energy Technology Data Exchange (ETDEWEB)

    Tal, A.; Leiberman, A.; Margulis, G.; Sofer, S.

    1988-01-01

    Ventricular function was evaluated using radionuclide ventriculography in 27 children with oropharyngeal obstruction and clinical features of obstructive sleep apnea. Their mean age was 3.5 years (9 months to 7.5 years). Conventional clinical assessment did not detect cardiac involvement in 25 of 27 children; however, reduced right ventricular ejection fraction (less than 35%) was found in 10 (37%) patients (mean: 19.5 +/- 2.3% SE, range: 8-28%). In 18 patients wall motion abnormality was detected. In 11 children in whom radionuclide ventriculography was performed before and after adenotonsillectomy, right ventricular ejection fraction rose from 24.4 +/- 3.6% to 46.7 +/- 3.4% (P less than 0.005), and in all cases wall motion showed a definite improvement. In five children, left ventricular ejection fraction rose greater than 10% after removal of oropharyngeal obstruction. It is concluded that right ventricular function may be compromised in children with obstructive sleep apnea secondary to adenotonsillar hypertrophy, even before clinical signs of cardiac involvement are present.

  9. Concentric left ventricular morphology in aerobically trained kayak canoeists.

    Science.gov (United States)

    Gates, Phillip E; Campbell, Ian G; George, Keith P

    2004-09-01

    The aim of the present study was to test the hypothesis that upper body aerobically trained athletes (kayak canoeists) would have greater left ventricular wall thickness, but similar left ventricular diastolic chamber dimensions, compared with recreationally active and sedentary men. Ultrasound echocardiography was used to determine cardiac structure and function in highly trained kayak canoeists (n = 10), moderately active (n = 10) and sedentary men (n = 10). The septal and posterior left ventricular walls were approximately 0.2 cm thicker in kayak canoeists (P kayak canoeists had a concentric pattern of left ventricular adaptation to aerobic upper body training. Scaling the data to body composition indices had no effect on the outcome of the statistical analysis. There were no differences in resting Doppler left ventricular diastolic or systolic function among the groups. Ejection fraction was lower in the kayak canoeists, but the magnitude of the difference was within the normal variability for this measurement. Thus aerobically upper body trained athletes demonstrated a concentric pattern of cardiac enlargement, but resting left ventricle function was not different between athletes, moderately active and sedentary individuals.

  10. Pneumatic distension of ventricular mural architecture validated histologically

    Energy Technology Data Exchange (ETDEWEB)

    Burg, M.C.; Heindel, W. [University Hospital Muenster (Germany). Dept. of Clinical Radiology; Lunkenheimer, P. [University Hospital Muenster (Germany). Dept. of Experimental Thoraco-vascular Surgery; Niederer, P. [ETH and University of Zuerich (Switzerland). Inst. for Biomedical Engineering; Brune, C. [Twente Univ. (Netherlands). Dept. of Applied Mathematics; Redmann, K. [University Hospital Muenster (Germany). Center for Reproductive Medicine and Andrology; Smerup, M. [Aarhus University Hospital (Denmark). Dept. of Cardiothoracic and Vascular Surgery; Spiegel, U.; Becker, F. [University Hospital Muenster (Germany). Dept. Surgical Research; Maintz, D. [University Hospital Muenster (Germany). Dept. of Clinical Radiology; Cologne Univ. (Germany). Dept. of Radiology; Anderson, R.H. [Newcastle Univ., London (United Kingdom). Inst. of Genetic Medicine

    2016-11-15

    There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes. We prepared the remaining 2 hearts for histology by perfusion with formaldehyde. Increasing pressures of pneumatic distension elongated the ventricular walls, but produced insignificant changes in mural thickness. The distension exaggerated the spaces between the aggregated cardiomyocytes, compartmenting the walls into epicardial, central, and endocardial regions, with a feathered arrangement of transitions between them. Marked variation was noted in the thicknesses of the parts in the different ventricular segments, with no visible anatomical boundaries between them. Measurements of angulations revealed intruding and extruding populations of cardiomyocytes that deviated from a surface-parallel alignment. Scrolling through the stacks of tomographic images revealed marked spiraling of the aggregated cardiomyocytes when traced from base to apex. Our findings call into question the current assumption that cardiomyocytes are uniformly aggregated together in a tangential fashion. There is marked heterogeneity in the architecture of the different ventricular segments, with the aggregated units never extending in a fully transmural fashion.

  11. Echocardiographic evaluation of right ventricular function in preterm infants with bronchopulmonary dysplasia.

    Science.gov (United States)

    Bokiniec, Renata; Własienko, Paweł; Borszewska-Kornacka, Maria; Szymkiewicz-Dangel, Joanna

    2017-04-01

    To evaluate right ventricular function in preterm infants with and without bronchopulmonary dysplasia. Eighty-nine preterm infants (bronchopulmonary dysplasia (n=32); (2) mild-bronchopulmonary dysplasia (n=35); (3) severe-bronchopulmonary dysplasia (n=15). Right ventricular echocardiographic parameters included the following: (1) pulsed-wave Doppler through the tricuspid valve (E/A ratio), pulmonary artery acceleration time, right ventricular ejection time, right ventricular velocity-time integral; (2) tissue Doppler measurements of myocardial velocities and atrioventricular conduction times; (3) pulsed-wave Doppler and tissue Doppler evaluation of myocardial performance index and E/E' ratio; and (4) M-mode detection of right ventricular end-diastolic wall diameter. The severe-bronchopulmonary dysplasia group had higher mean right ventricular myocardial performance index (on the 28th day of life by pulsed-wave Doppler) than the no-bronchopulmonary dysplasia (P=.014) or mild-bronchopulmonary dysplasia (P=.031) groups; no differences were found between no-bronchopulmonary dysplasia and mild-bronchopulmonary dysplasia groups (P=.919). A reduction in right ventricular myocardial performance index at later time points was observed in all three groups (Pbronchopulmonary dysplasia severity in other right ventricular echocardiographic parameters. Right ventricular myocardial performance index measured by pulsed-wave Doppler indicates impaired right ventricular function in preterm infants with severe bronchopulmonary dysplasia. © 2017, Wiley Periodicals, Inc.

  12. Systolic and Diastolic Left Ventricular Mechanics during and after Resistance Exercise.

    Science.gov (United States)

    Stöhr, Eric J; Stembridge, Mike; Shave, Rob; Samuel, T Jake; Stone, Keeron; Esformes, Joseph I

    2017-10-01

    To improve the current understanding of the impact of resistance exercise on the heart, by examining the acute responses of left ventricular (LV) strain, twist, and untwisting rate ("LV mechanics"). LV echocardiographic images were recorded in systole and diastole before, during and immediately after (7-12 s) double-leg press exercise at two intensities (30% and 60% of maximum strength, one-repetition maximum). Speckle tracking analysis generated LV strain, twist, and untwisting rate data. Additionally, beat-by-beat blood pressure was recorded and systemic vascular resistance (SVR) and LV wall stress were calculated. Responses in both exercise trials were statistically similar (P > 0.05). During effort, stroke volume decreased, whereas SVR and LV wall stress increased (P mechanics (P 0.05). Immediately after exercise, systolic LV mechanics returned to baseline levels (P mechanics, but increases diastolic mechanics after exercise, suggesting that resistance exercise has a differential impact on systolic and diastolic heart muscle function. The findings may explain why acute resistance exercise has been associated with reduced stroke volume but chronic exercise training may result in increased LV volumes.

  13. Presence of left ventricular contractile reserve predicts midterm response to cardiac resynchronization therapy--results from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) trial.

    Science.gov (United States)

    Muto, Carmine; Gasparini, Maurizio; Neja, Carlo Peraldo; Iacopino, Saverio; Davinelli, Mario; Zanon, Francesco; Dicandia, Cosimo; Distefano, Giuseppe; Donati, Roberto; Calvi, Valeria; Denaro, Alessandra; Tuccillo, Bernardino

    2010-11-01

    Cardiac resynchronization therapy (CRT) is effective in selected patients with heart failure (HF). Nevertheless, the nonresponder rate remains high. The low-dose dobutamine stress-echo (DSE) test detects the presence of left ventricular (LV) contractile reserve (LVCR) in HF patients of any etiology and may be useful in predicting response to resynchronization. The purpose of this study was to present the results of the LODO-CRT trial, which evaluated whether LVCR presence at baseline increases the chances of response to CRT. LODO-CRT is a multicenter prospective study that enrolled CRT candidates according to guidelines. LVCR presence was defined as an LV ejection fraction increase >5 units during DSE test. CRT response is assessed at 6-month follow-up as an LV end-systolic volume reduction ≥10%. Two hundred seventy-one patients were enrolled. The DSE test was feasible without complications in 99% of patients. Nine patients died from noncardiac disease, and 31 presented inadequate data. Two hundred thirty-one patients were included in the analysis. Mean patient age was 67 ± 10 years; 95% were in New York Heart Association class III, and 42% had HF of ischemic etiology. Mean QRS and LV ejection fraction were 147 ± 25 ms and 27% ± 6%, respectively. LVCR presence was found in 185 subjects (80%). At follow-up, 170 (74%) patients responded to CRT, 145/185 in the group with LVCR (78%) and 25/46 (54%) in the group without LVCR. Difference in responder proportion to CRT was 24% (P <.001). Reported test sensitivity is 85%. The DSE test in CRT candidates is safe and feasible. LVCR presence at baseline increases the chances of response to CRT. Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. Combined therapy with shock wave and autologous bone marrow-derived mesenchymal stem cells alleviates left ventricular dysfunction and remodeling through inhibiting inflammatory stimuli, oxidative stress & enhancing angiogenesis in a swine myocardial infarction model.

    Science.gov (United States)

    Sheu, Jiunn-Jye; Lee, Fan-Yen; Yuen, Chun-Man; Chen, Yi-Ling; Huang, Tien-Hung; Chua, Sarah; Chen, Yung-Lung; Chen, Chih-Hung; Chai, Han-Tan; Sung, Pei-Hsun; Chang, Hsueh-Wen; Sun, Cheuk-Kwan; Yip, Hon-Kan

    2015-08-15

    We hypothesized that combined therapy with shock wave (SW) and autologous bone marrow-derived mesenchymal stem cells (BMDMSCs) is superior to either therapy alone for alleviating left ventricular (LV) dysfunction. Male mini-pigs (n=30) equally divided into group 1 (sham control), group 2 [acute myocardial infarction (AMI) by left coronary artery ligation], group 3 (AMI-SW), group 4 (AMI-BMDMSC), and group 5 (AMI-SW-BMDMSC) were sacrificed by day 60 and the hearts were collected for studies. Baseline LV injection fraction [LVEF (%)] and LV chamber size did not differ among the five groups (p>0.5). By day 60, LVEF was highest in group 1 and lowest in group 2, significantly higher in group 5 than that in groups 3 and 4, and significantly higher in group 4 than that in group 3 (p<0.001). Cellular and protein levels of VEGF, CXCR4, and SDF-1α were significantly increased progressively from groups 1 to 5 (all p<0.05). Small vessel number and protein expressions of CD31 and eNOS were highest in groups 1 and 5, lowest in group 2, and significantly higher in group 4 than those in group 3 (p<0.001). Protein (MMP-9, TNF-1α and NF-κB) and cellular (CD14+, CD40+) levels of inflammatory biomarkers, protein expressions of oxidative stress (oxidized protein, NOX-1, NOX-2), apoptosis (Bax, caspase-3, PARP), infarct size, and LV dimensions showed a pattern opposite to that of LVEF among all groups (all p<0.001). Combined SW-BMDMSC therapy is superior to either therapy alone for improving LVEF, reducing infarct size, and inhibiting LV remodeling. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Antiarrhythmic and arrhythmogenic action of inosine in experimental ventricular tachyarrhythmias

    OpenAIRE

    De Micheli, Alfredo; Pastelín,Gustavo; Chávez Domínguez,Rafael; Iturralde Torres,Pedro; Medrano,Gustavo A.

    2009-01-01

    Objective: To study the possible action of inosine on experimental ventricular tachyarrhythmias. Material and methods: We used 92 mongrel dogs weighing 13 kg-17 kg, anesthetized with 30 mg/kg sodium pentobarbital applied intravenously. Myocardial lesions were induced by injecting 1ml-1.5 ml of 70% phenol in the free wall of the left ventricle. In 36 dogs, the ventricular arrhythmia (VT) was induced 30 min later with aconitine crystals inserted into the periphery of the damaged area; in 16, VT...

  16. Influence of the Accuracy of Angiography-Based Reconstructions on Velocity and Wall Shear Stress Computations in Coronary Bifurcations: A Phantom Study.

    Directory of Open Access Journals (Sweden)

    Jelle T C Schrauwen

    Full Text Available Wall shear stress (WSS plays a key role in the onset and progression of atherosclerosis in human coronary arteries. Especially sites with low and oscillating WSS near bifurcations have a higher propensity to develop atherosclerosis. WSS computations in coronary bifurcations can be performed in angiography-based 3D reconstructions. It is essential to evaluate how reconstruction errors influence WSS computations in mildly-diseased coronary bifurcations. In mildly-diseased lesions WSS could potentially provide more insight in plaque progression.Four Plexiglas phantom models of coronary bifurcations were imaged with bi-plane angiography. The lumens were segmented by two clinically experienced readers. Based on the segmentations 3D models were generated. This resulted in three models per phantom: one gold-standard from the phantom model itself, and one from each reader. Steady-state and transient simulations were performed with computational fluid dynamics to compute the WSS. A similarity index and a noninferiority test were used to compare the WSS in the phantoms and their reconstructions. The margin for this test was based on the resolution constraints of angiography.The reconstruction errors were similar to previously reported data; in seven out of eight reconstructions less than 0.10 mm. WSS in the regions proximal and far distal of the stenosis showed a good agreement. However, the low WSS areas directly distal of the stenosis showed some disagreement between the phantoms and the readers. This was due to small deviations in the reconstruction of the stenosis that caused differences in the resulting jet, and consequently the size and location of the low WSS area.This study showed that WSS can accurately be computed within angiography-based 3D reconstructions of coronary arteries with early stage atherosclerosis. Qualitatively, there was a good agreement between the phantoms and the readers. Quantitatively, the low WSS regions directly distal to

  17. 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.

  18. V-ATPase-dependent luminal acidification is required for endocytic recycling of a yeast cell wall stress sensor, Wsc1p

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kazuma; Saito, Mayu; Nagashima, Makiko; Kojima, Ai; Nishinoaki, Show [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Junko Y., E-mail: yama_jun@aoni.waseda.jp [Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Jiro, E-mail: jtosiscb@rs.noda.tus.ac.jp [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan)

    2014-01-10

    Highlights: •A targeted genome screen identified 5 gene groups affecting Wsc1p recycling. •V-ATPase-dependent luminal acidification is required for Wsc1p recycling. •Activity of V-ATPase might be required for cargo recognition by the retromer complex. -- Abstract: Wsc1p is a major cell wall sensor protein localized at the polarized cell surface. The localization of Wsc1p is maintained by endocytosis and recycling from endosomes back to the cell surface, but changes to the vacuole when cells are subjected to heat stress. Exploiting this unique property of Wsc1p, we screened for yeast single-gene deletion mutants exhibiting defects in Wsc1p trafficking. By expressing 3GFP-tagged Wsc1p in mutants with deleted genes whose function is related to intracellular trafficking, we identified 5 gene groups affecting Wsc1p trafficking, impaired respectively in endocytic internalization, multivesicular body sorting, the GARP complex, endosomal maturation/vacuolar fusion, and V-ATPase. Interestingly, deletion of the VPH1 gene, encoding the V{sub o} subunit of vacuolar-type H{sup +}-ATPase (V-ATPase), led to mis-localization of Wsc1p from the plasma membrane to the vacuole. In addition, disruption of other V-ATPase subunits (vma mutants) also caused defects of Wsc1p trafficking and vacuolar acidification similar to those seen in the vph1Δ mutant. Moreover, we found that deletion of the VPS26 gene, encoding a subunit of the retromer complex, also caused a defect in Wsc1p recycling and mis-localization of Wsc1p to the vacuole. These findings clarified the previously unidentified Wsc1p recycling pathway and requirement of V-ATPase-dependent luminal acidification for Wsc1p recycling.

  19. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...... and flat, “ambiguous walls” combine softness, tectonics and three-dimensionality. The paper considers a selection of luminious surfaces and reflects on the extent of their ambiguous qualities. Initial ideas for new directions for the wall will be essayed through the discussion....

  20. Epicardial radiofrequency ablation for left ventricular aneurysm related ventricular arrhythmias during off-pump coronary artery bypass surgery.

    Science.gov (United States)

    Yu, Yang; Gao, Ming-Xin; Li, Hai-Tao; Zhang, Fan; Gu, Cheng-Xiong

    2012-11-01

    Left ventricular aneurysm (LVA) is one of the serious complications after acute myocardial infarction. We attempted to evaluate the preliminary efficacy of LVA repair combined with epicardial radiofrequency ablation for ventricular arrhythmia during off-pump coronary artery bypass grafting (OPCAB). From June 2009 to April 2011, 31 patients with LVA had angina symptoms and ventricular arrhythmia. In all patients, circular and cross-shaped radiofrequency epicardial ablations were performed using unipolar ablation pen along the border between the aneurysm wall and normal cardiac tissue and in the central zone of the aneurysms, followed by a linear placation of ventricular aneurysms on beating heart. All the patients showed complete recovery. The average number of grafted vessels was 2.7 ± 1.3. Intraoperative examinations revealed that the ventricular arrhythmia was effectively controlled by radiofrequency ablation. All cases had been followed up for one year. Holter monitoring revealed a significant reduction in ventricular arrhythmias (P aneurysm and preoperative malignant arrhythmia, aneurysm repair plus epicardial radiofrequency ablation in OPCAB was found to be an effective and feasible therapeutic technique. However, medium- to long-term therapeutic efficacy of this method remains to be determined by future studies and observations.

  1. Prevalence of cardiac dyssynchrony and correlation with atrio-ventricular block and QRS width in dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Anzouan-Kacou, J B; Ncho-Mottoh, M P; Konin, C

    2012-01-01

    Cardiac dyssynchrony causes disorganised cardiac contraction, delayed wall contraction and reduced pumping efficiency. We aimed to assess the prevalence of different types of dyssynchrony in patients with dilated cardiomyopathy (DCM), and to establish the correlation between atrio-ventricular blo...

  2. Reversibility of stress-echo induced ST-segment depression by long-term oral n-3 PUFA supplementation in subjects with chest pain syndrome, normal wall motion at stress-echo and normal coronary angiogram

    Directory of Open Access Journals (Sweden)

    Ziacchi Vigilio

    2004-03-01

    Full Text Available Abstract Background Normal coronary arteries may coexist with abnormal coronary and systemic endothelial function in patients with chest pain. Recent work by the renowned Pisa echo-group elegantly suggests that isolated ST-segment depression during stress-echo (SE can be used as a marker of coronary endothelial dysfunction, in the absence of stress-inducible wall motion abnormalities and in the absence of angiographically-significant coronary artery disease (CAD. The long chain n-3 polyunsaturated fatty acids (PUFAs have been reported to possess several properties that may positively influence vascular function. The present study's hypothesis is that a 4 month-course of oral supplementation with n-3 PUFAs can reverse endothelial dysfunction. Methods Subjects were selected on the basis of the following criteria: 1 reported chest pain syndrome, 2 significant ST-segment depression during an otherwise normal SE, 3 absence of angiographically-significant CAD. Subjects underwent a 4-month course of oral supplementation with commercially available n-3 PUFA, 1 g once a day. Normalization of endothelial dysfunction was defined, at the end of the supplementation period, by the absence of significant ST-segment depression during repeat SE. We tested the aforementioned hypothesis in a very small series of consecutive subjects, with the intent to produce a hypothesis-generating study. Results Seven out of the total nine subjects enrolled (77.8% had normal ST-segment during repeat SE performed after the 4 month course of therapy. Conclusions A striking rate of reversion of SE-induced ST-segment depression after oral n-3 PUFAs suggests reversion of coronary endothelial dysfunction; nonetheless these data need to be validated in larger, placebo-controlled studies.

  3. The value of revascularization and adherence to therapy in the development of cardiovascular complications in long-term monitoring of patients with myocardial infarction of the right ventricle on the background of the Q-myocardial infarction of the left ventricular posterior wall

    Directory of Open Access Journals (Sweden)

    V.Y. Tseluyko

    2016-03-01

    Full Text Available The aim – to evaluate the role of deferred revascularization and adherence to drug therapy as factors affecting long-term prognosis of patients with myocardial infarction (MI of the right ventricle (RV on the background of the Q-myocardial infarction of the left ventricle (LV posterior wall (PW. Materials and methods. The study involved 155 patients with MI of the RV due the Q-MI of the PWLV, age 64.11 ± 0.78 years. The revascularization (PCI, CABG was performed within one year after MI. Adherence to treatment was assessed after 6 and 30 months. The combined endpoints included: unstable angina (UA, Re-MI, stroke and cardio-vascular (CV death. Follow-up was 30.6 ± 4.5 month. Results. The 1st group included 68 (43.9 % patients who underwent surgical treatment, 87 (56.1 % patients under conservative strategy composed the 2nd group. The frequency of combined CV-point was significantly lower in the 1st group (ð = 0.00001. Revascularization after RV MI was accompanied by significant decrease of frequency of Re-MI (ð = 0.05, stroke (ð = 0.0413 and UA (ð = 0.00001 during 30 months follow-up. Reducing risk of CV events in the 1st group was associated with higher adherence to ACE inhibitors / ARA (86.7–79.4 %, statins (97.1–64.7 % and clopidogrel (98.5–79.4 % at 6 months and at the end of the observation period, compared to patients with conservative strategy (p < 0.05. Conclusions. Higher adherence to drug therapy in the surgical treatment group is associated with significantly lower number of cardiovascular events during 30 days after right ventricular myocardial infarction.

  4. Determination of left ventricular mass through SPECT imaging

    Science.gov (United States)

    Zárate-Morales, A.; Rodríguez-Villafuerte, M.; Martínez-Rodríguez, F.; Arévila-Ceballos, N.

    1998-08-01

    An edge detection algorithm has been applied to estimate left ventricular (LV) mass from single photon emission computed tomography (SPECT) thallium-201 images. The algorithm was validated using SPECT images of a phantom. The algorithm was applied to 20 patient studies from the Hospital de Cardiologia, Centro Médico Nacional Siglo XXI. Left ventricular masses derived from the stress and redistribution studies were highly correlated (r=0.96). The average LV masses obtained were 162±37 g and 169±34 g in the redistribution and stress studies, respectively.

  5. Ventricular arrhythmias associated with long-term endurance sports: what is the evidence?

    Science.gov (United States)

    Heidbuchel, Hein; Prior, David L; La Gerche, André

    2012-11-01

    Athletic performance tests the limits of the human body and mind. Awe-inspiring achievements is what makes sports so fascinating. It is well appreciated however that top-level sports may sometimes overtax the body, and can lead to injuries, most notably of musculo-skeletal nature. This paper defends the thesis that the heart can also develop sports injuries at the ventricular level. We will elaborate on our hypothesis, originally put forward in 2003, that intense endurance activities put a particularly high strain on the right ventricle (RV), which over time, may lead to a proarrhythmic state resembling right (or less often) left ventricular cardiomyopathy. This can develop even in the absence of underlying demonstrable genetic abnormalities, probably just as a result of excessive RV wall stress during exercise. The syndrome of 'exercise-induced arrhythmogenic RV cardiomyopathy' may easily be overlooked. Sports cardiologists, like orthopaedic specialists, should be prepared to realise that excessive sports activity can lead to cardiac sports injuries in some, which will help to council on safe participation in all.

  6. A modified infarct exclusion technique for repair of anteroapical postinfarction ventricular septal defect.

    Science.gov (United States)

    Bayezid, Omer; Turkay, Cengiz; Golbasi, Ilihan

    2005-01-01

    Ventricular septal defects complicate approximately 1% to 2% of cases of acute myocardial infarction. Such postinfarction defects require urgent surgical treatment because, on medical treatment alone, 60% to 70% of patients die within the first 2 weeks. Despite the development of various surgical techniques for repair of postinfarction ventricular septal defect, the condition carries a high risk of recurrence and subsequent death. We describe a modification of the infarct exclusion technique in which the septal portion of the patch is reinforced by the right ventricular free wall. This modification appears to prevent leaks to the right ventricle through the ventricular septal defect, from anywhere around the patch. We applied this modified technique to 4 patients with anteroapical postinfarction ventricular septal defect. There was 1 early death, due to mesenteric artery occlusion secondary to embolus. No residual shunt was found during the postoperative period. We believe that our modification to the infarct exclusion technique might reduce both operative mortality and recurrence, by supporting friable endocardial tissue with right ventricular wall. We suggest that it be considered for use in patients with anteroapical ventricular septal defect and no severe right ventricular dysfunction.

  7. Evaluation of myocardial viability in old myocardial infarcted patients with CHF: delayed enhancement MRI vs. low-dose dobutamine stress speckle tracking echocardiography.

    Science.gov (United States)

    Wang, Chaofan; Han, Shuguang; Xu, Tongda; Wang, Fengli; Wang, Xiaoping; Chen, Jing; Hu, Chunfeng; Li, Dongye

    2016-01-01

    The aim of this study was to explore the significance of delayed enhancement magnetic resonance imaging (DE-MRI) combined with two-dimensional speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) to assess viable myocardium (VM) in the patients with old myocardial infarction (OMI) associated with congestive heart failure (CHF). Thirty five hospitalized OMI patients with regional wall motion abnormalities and left ventricular ejection fraction (LVEF) CHF.

  8. Prognostic value of treadmill stress echocardiography at extremes of exercise performance: submaximal high exercise capacity ≥ 10 metabolic equivalents.

    Science.gov (United States)

    Yao, Siu-Sun; Agarwal, Vikram; Chaudhry, Farooq A

    2014-03-01

    Submaximal stress testing or achieving High exercise capacity (≥ 10 metabolic equivalents, METS) is a predictor of favorable prognosis. The purpose of this study was to evaluate the prognostic value of submaximal or high exercise capacity stress echocardiography. We evaluated 1781 patients (55 ± 13 years; 59% male) undergoing treadmill stress echocardiography divided into 811 patients with submaximal (high exercise capacity (≥ 10 METS). Resting left ventricular ejection fraction and regional wall motion were assessed. The left ventricle was divided into 16 segments and scored on 5-point scale of wall motion. Abnormal stress echocardiography was defined as stress-induced ischemia (wall-motion score of ≥ 1 grade). Follow-up (3.3 ± 1.5 years) for nonfatal myocardial infarction (MI) (n = 40) and cardiac death (n = 52) were obtained. By univariate analysis, echocardiographic variables of ejection fraction, peak wall-motion score index (WMSI) and number of new ischemic wall-motion abnormalities were significant predictors of cardiac events. Cumulative survival was significantly worse in patients with abnormal (ischemic) versus normal (nonischemic) stress echocardiography in submaximal (4.4%/year vs. 1.3%/year, P high exercise capacity (1.5%/year vs. 0.2%/year, P high exercise capacity studies. © 2013, Wiley Periodicals, Inc.

  9. Exercise-induced intra-ventricular gradients as a frequent potential cause of myocardial ischemia in cardiac syndrome X patients

    Directory of Open Access Journals (Sweden)

    Almeida Ana G

    2008-01-01

    Full Text Available Abstract Background The development of intra-ventricular gradients (IVG during dobutamine or exercise stress is not infrequent, and can be associated to symptoms during stress. The purpose of this study was to assess the occurrence of IVG during exercise stress echocardiography in cardiac syndrome X patients. Methods We prospectively evaluated 91 patients (pts mean aged 51 ± 12 years (age ranged 20 to 75 years old, 44 of whom were women. All pts had angina, positive exercise ECG treadmill testing, normal rest echocardiogram and no coronary artery disease on coronary angiogram (cardiac X syndrome. After complete Doppler echocardiographic evaluation with determination of left ventricular outflow tract index (LVOTi, relative left ventricular wall thickness (RLVWT and left ventricular end-diastolic volume index (LVDVi, all patients underwent stress echocardiography with two-dimensional and Doppler echographic evaluation during and after treadmill exercise. Results For analysis purpose patients were divided in 2 groups, according to the development of IVG. Doppler evidence of IVG was found in 33 (36% of the patients (Group A, with mean age 47 ± 14 years old (age ranged 20 to 72 years and with a mean end-systolic peak gradient of 86 ± 34 mmHg (ranging from 30 to 165 mmHg. The IVG development was accompanied by SAM of the mitral valve in 23 pts. Three of these pts experienced symptomatic hypotension. Ten were women (30% pts. 58 pts in group B, 34 of whom were women (59% (p = 0,01 vs group A, mean aged 53,5 ± 10,9 years old (age ranged 34 to 75 years (p = 0,03 vs group A, did not develop IVG. LVOTi was 10,29 ± 0,9 mm/m2 in group A and 11,4 ± 1 mm/m2 in group B (p 2 in group A and 56 ± 11,6 ml/m2 in group B (p = 0,000. Conclusion 1. A significant number of patients with cardiac X syndrome developed IVG during upright exercise in treadmill. These pts (group A are mainly males and younger than those who did not develop IVG. 2. The development of IVG

  10. Left ventricular mural thrombus

    Energy Technology Data Exchange (ETDEWEB)

    Nixon, J.V.

    1983-08-01

    The identification of mural thrombus in patients with left ventricular aneurysm and mural thrombus probably warrants consideration of long-term anticoagulation. In patients with acute, large, anterior or anteroapical, transmural myocardial infarctions, serial noninvasive examinations are warranted to define a group of patients at high risk for the development of left ventricular aneurysm and/or mural thrombus. Anticoagulants should be considered in patients in whom mural thrombi develop as a complication of their infarction. Patients with congestive cardiomyopathy should be considered for long-term anticoagulation. These recommendations are all tempered by the realization that the use of anticoagulant therapy is not without its own risks. The decision to anticoagulate must be balanced against each individual patient's suitability for such therapy and the individual likelihood of the development of side effects.

  11. Arrhythmogenic right ventricular dysplasia.

    Science.gov (United States)

    Kinsara, A J; Zaman, L; Gorgels, A

    2001-01-01

    Right ventricular dysplasia (RVD) is a disease entity of unknown cause that is characterised by partial or total replacement of RV-muscle by adipose or fibrous tissue. It is a well-recognized cause of arrhythmia and premature sudden death, but usually underdiagnosed. Several noninvasive and invasive diagnostic modalities have been used, however, all may not be positive in a given case. Drug therapy with class 1c, beta-blocker, and amiodarone in variable combination produce varying success rates in preventing recurrent ventricular tachycardia. Failure of the above measures calls for insertion of implantable cardioverter defibrillator. The attention of emergency physicians is drown to this disease as they are the first medical personnel to be presented with this disease as an emergency. Hence their recognition of RVD will ensure early and proper management.

  12. Arrhythmogenic right ventricular cardiomyopathy.

    Science.gov (United States)

    Soni, Roopali; Oade, Yvette

    2011-08-24

    Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited disease of the heart muscle that causes ventricular tachyarrhythmias and sudden death in young people and athletes. It results in fibrofatty replacement of the right ventricle, and the subepicardial region of the left ventricle. It is the most common cause of sudden cardiac death in young people after hypertrophic heart disease. Diagnosis can be difficult and at present there is no cure for ARVC. Prevention of sudden death is the most important management strategy. Paediatricians need to be aware of the possibility of ARVC in adolescents and young adults presenting with palpitations, fatigue, syncope or cardiac arrest. The authors present two cases of apparently healthy teenage boys who died suddenly and unexpectedly. Postmortem examination of the myocardium was strongly suggestive of ARVC in both cases.

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

    Directory of Open Access Journals (Sweden)

    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. Idiopathic Fascicular Ventricular Tachycardia

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2004-07-01

    Full Text Available Idiopathic fascicular ventricular tachycardia is an important cardiac arrhythmia with specific electrocardiographic features and therapeutic options. It is characterized by relatively narrow QRS complex and right bundle branch block pattern. The QRS axis depends on which fascicle is involved in the re-entry. Left axis deviation is noted with left posterior fascicular tachycardia and right axis deviation with left anterior fascicular tachycardia. A left septal fascicular tachycardia with normal axis has also been described. Fascicular tachycardia is usually seen in individuals without structural heart disease. Response to verapamil is an important feature of fascicular tachycardia. Rare instances of termination with intravenous adenosine have also been noted. A presystolic or diastolic potential preceding the QRS, presumed to originate from the Purkinje fibers can be recorded during sinus rhythm and ventricular tachycardia in many patients with fascicular tachycardia. This potential (P potential has been used as a guide to catheter ablation. Prompt recognition of fascicular tachycardia especially in the emergency department is very important. It is one of the eminently ablatable ventricular tachycardias. Primary ablation has been reported to have a higher success, lesser procedure time and fluoroscopy time

  15. Second statement of the working group on electrocardiographic diagnosis of left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Bacharova, Ljuba; Estes, E Harvey; Bang, Lia E

    2011-01-01

    The Working Group on Electrocardiographic Diagnosis of Left Ventricular Hypertrophy, appointed by the Editor of the Journal of Electrocardiology, presents the alternative conceptual model for the ECG diagnosis of left ventricular hypertrophy (LVH). It is stressed that ECG is a record of electrical...

  16. Arrhythmogenic right ventricular dysplasia: MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Wall, E.E. van der; Bootsma, M.M.; Schalij, M.J. [Dept. of Cardiology, Leiden Univ. Medical Center, Leiden (Netherlands); Kayser, H.W.M.; Roos, A. de [Dept. of Radiology, Leiden Univ. Medical Center, Leiden (Netherlands)

    2000-06-01

    Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called ''triangle of dysplasia'', i. e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD. (orig.) [German] Die arrhythmogene rechtsventrikulaere Dysplasie (ARVD), eine Herzmuskelerkrankung unklarer Aetiologie, ist pathologisch durch fettige Degeneration des rechtsventrikulaeren Myokards gekennzeichnet. Die klinischen Symptome

  17. Ventricular hypertrophy in cardiomyopathy.

    Science.gov (United States)

    Oakley, C

    1971-01-01

    Semantic difficulties arise when hypertrophic obstructive cardiomyopathy is seen without obstruction and with congestive failure, and also when congestive cardiomyopathy is seen with gross hypertrophy but without heart failure. Retention of a small left ventricular cavity and a normal ejection fraction characterizes hypertrophic cardiomyopathy at all stages of the disorder. Congestive cardiomyopathy is recognized by the presence of a dilated left ventricular cavity and reduced ejection fraction regardless of the amount of hypertrophy and the presence or not of heart failure. Longevity in congestive cardiomyopathy seems to be promoted when hypertrophy is great relative to the amount of pump failure as measured by increase in cavity size. Conversely, death in hypertrophic cardiomyopathy is most likely when hypertrophy is greatest at a time when outflow tract obstruction has been replaced by inflow restriction caused by diminishing ventricular distensibility. Hypertrophy is thus beneficial and compensatory in congestive cardiomyopathy, whereas it may be the primary disorder and eventual cause of death in hypertrophic cardiomyopathy. Reasons are given for believing that hypertension may have been the original cause of left ventricular dilatation in some case of congestive cardiomyopathy in which loss of stroke output thenceforward is followed by normotension. Development of severe hypertension in these patients after recovery from a prolonged period of left ventricular failure with normotension lends weight to this hypothesis. No fault has been found in the large or small coronary arteries in either hypertrophic cardiomyopathy or congestive cardiomyopathy when they have been examined in life by selective coronary angiography, or by histological methods in biopsy or post-mortem material. Coronary blood supply may be a limiting factor in the compensatory hypertrophy of congestive cardiomyopathy, and the ability to hypertrophy may explain the better prognosis of some

  18. Flow and wall shear stress in end-to-side and side-to-side anastomosis of venous coronary artery bypass grafts

    Directory of Open Access Journals (Sweden)

    Poulikakos Dimos

    2007-09-01

    Full Text Available Abstract Purpose Coronary artery bypass graft (CABG surgery represents the standard treatment of advanced coronary artery disease. Two major types of anastomosis exist to connect the graft to the coronary artery, i.e., by using an end-to-side or a side-to-side anastomosis. There is still controversy because of the differences in the patency rates of the two types of anastomosis. The purpose of this paper is to non-invasively quantify hemodynamic parameters, such as mass flow and wall shear stress (WSS, in end-to-side and side-to-side anastomoses of patients with CABG using computational fluid dynamics (CFD. Methods One patient with saphenous CABG and end-to-side anastomosis and one patient with saphenous CABG and side-to-side anastomosis underwent 16-detector row computed tomography (CT. Geometric models of coronary arteries and bypasses were reconstructed for CFD analysis. Blood flow was considered pulsatile, laminar, incompressible and Newtonian. Peri-anastomotic mass flow and WSS were quantified and flow patterns visualized. Results CFD analysis based on in-vivo CT coronary angiography data was feasible in both patients. For both types of CABG, flow patterns were characterized by a retrograde flow into the native coronary artery. WSS variations were found in both anastomoses types, with highest WSS values at the heel and lowest WSS values at the floor of the end-to-side anastomosis. In contrast, the highest WSS values of the side-to-side anastomosis configuration were found in stenotic vessel segments and not in the close vicinity of the anastomosis. Flow stagnation zones were found in end-to-side but not in side-to-side anastomosis, the latter also demonstrating a smoother stream division throughout the cardiac cycle. Conclusion CFD analysis of venous CABG based on in-vivo CT datasets in patients was feasible producing qualitative and quantitative information on mass flow and WSS. Differences were found between the two types of anastomosis

  19. CASE REPORT Arrythmogenic right ventricular dysplasia ...

    African Journals Online (AJOL)

    RBBB: right bundle-branch block. RV: right ventricular. RVEDV: right ventricular end diastolic volume. RVEF: right ventricular ejection fraction. RVOT: right ventricular outflow tract. SAECG: signal averaged electrocardiogram. VT: ventricular tachycardia. 'Modifications of the orginal criteria have been proposed to facilitate ...

  20. Epicardial deployment of right ventricular disk during perventricular device closure in a child with apical muscular ventricular septal defect

    Directory of Open Access Journals (Sweden)

    Nageswara Rao Koneti

    2013-01-01

    Full Text Available We report a successful perventricular closure of an apical muscular ventricular septal defect (mVSD by a modified technique. An eight-month-old infant, weighing 6.5 kilograms, presented with refractory heart failure. The transthoracic echocardiogram showed multiple apical mVSDs with the largest one measuring 10 mm. perventricular device closure using a 12 mm Amplatzer mVSD occluder was planned. The left ventricular disk was positioned approximating the interventricular septum; however, the right ventricular (RV disk was deployed on the free wall of the RV due to an absent apical muscular septum and a small cavity at the apex. The RV disk of the device was covered using an autologous pericardium. His heart failure improved during follow-up.

  1. Martius flap and anterior vaginal wall sling for correction of urethrovaginal fistula (UVF associated with stress urinary incontinence (SUI after vaginal delivery

    Directory of Open Access Journals (Sweden)

    A.M. Abdelbary

    2012-12-01

    Conclusions: Patients with a post-birth trauma in the form of UVF should be examined intra-operatively for the presence of associated SUI following correction of UVF. The use of the Martius flap and anterior vaginal wall sling in treating such patients is safe, efficient and reproducible. An anterior vaginal wall sling should be avoided in distal UVF to avoid recurrence of SUI.

  2. Surgical Repair of Post-Infarct True Posterobasal Ventricular Aneurysm with Mitral Valve Replacement and Coronary Revascularization: a Case Report

    Directory of Open Access Journals (Sweden)

    Dasarathan Charumathi

    2012-03-01

    Full Text Available Post-infarction ventricular aneurysm is a complication of myocardial infarction. While the involvement of the anterior wall is quite common, posterobasal left ventricular aneurysm is a rare clinical complication in this setting. In this case report, we report a post-infarction posterobasal left ventricular aneurysm combined with ischemic mitral regurgitation due to coronary artery disease, for which we successfully performed triple coronary artery bypass and ventricular geometry restitution via a modified Dor’s procedure with mitral valve replacement through an extracardiac approach.1

  3. Neonatal aortic arch obstruction due to pedunculated left ventricular foetal myxoma.

    Science.gov (United States)

    Kaulitz, Renate; Haen, Susanne; Sieverding, Ludger

    2015-10-01

    Myxoma in neonatal life are extremely rare. We report a case of a neonate with a pedunculated cardiac tumour arising from the anterolateral left ventricular wall protruding across the left ventricular outflow tract and continuously extending into the distal aortic arch. Surgical removal at 14 days of age via combined transaortic approach and apical ventriculotomy was indicated because of the risk of further compromise of aortic valve function and aortic arch obstruction. Histopathologic examination was consistent with a myxoma.

  4. Comparison of Electrocardiographic Criteria for Identifying Left Ventricular Hypertrophy in Athletes from Different Sports Modalities

    Directory of Open Access Journals (Sweden)

    Nelson Samesima

    Full Text Available OBJECTIVES: In athletes, isolated electrocardiogram high voltage criteria are widely used to evaluate left ventricular hypertrophy, but positive findings are thought to represent normal electrocardiogram alterations. However, which electrocardiogram criterion can best detect left ventricular hypertrophy in athletes of various sport modalities remains unknown. METHODS: Five electrocardiogram criteria used to detect left ventricular hypertrophy were tested in 180 male athletes grouped according to their sport modality: 67% low-static and high-dynamic components and 33% high-static and high-dynamic components of exercise. The following echocardiogram parameters are the gold standard for diagnosing left ventricular hypertrophy: left ventricular mass index ≥134 g.m-2, relative wall thickness ≥0.42 mm, left ventricular diastolic diameter index ≥32 mm.m-2, septum wall thickness ≥13 mm, and posterior wall thickness ≥13 mm. Results for the various criteria were compared using the kappa coefficient. Significance was established at p<0.05. RESULTS: Fifty athletes (28% presented with left ventricular hypertrophy according to electrocardiogram findings, with the following sensitivities and specificities, respectively: 38-53% and 79-83% (Perugia, 22-40% and 89-91% (Cornell, 24-29% and 90% (Romhilt-Estes, 68-87% and 20-23% (Sokolow-Lyon, and 0% and 99% (Gubner. The Perugia and Cornell criteria had higher negative predictive values for the low-static and high-dynamic subgroup. Kappa coefficients were higher for Romhilt-Estes, Cornell and Perugia criteria than for Sokolow-Lyon and Gubner criteria. CONCLUSION: All five evaluated criteria are inadequate for detecting left ventricular hypertrophy, but the Perugia, Cornell and Romhilt-Estes criteria are useful for excluding its presence. The Perugia and Cornell criteria were more effective at excluding left ventricular hypertrophy in athletes involved in a sport modality with low-static and high

  5. Taquicardia ventricular polimórfica catecolaminérgica Catecholaminergic polymorphic ventricular tachycardia

    Directory of Open Access Journals (Sweden)

    Alejandro Velasco

    2009-04-01

    Full Text Available Catecholaminergic Polymorphic Ventricular Tachycardia is an inherited heart rhythm disorder recently discovered by genetic and electrophysiological diagnostic advancements. It consists of an inherited disorder characterized by the induction of bi-directional ventricular tachycardia in the presence of catecholamines, without a structural cardiac abnormality. Mutations in the Ryanodine receptor gene RyR2, have been linked with an autosomic dominant form, while mutations in the Calsequestrin gene CASQ 2 have showed correlation with an autosomic recessive form. The average age of onset is between 7 and 9 years of age, and clinical symptoms vary from syncope to sudden cardiac death. The diagnosis is confirmed by inducting ventricular tachycardia through a stress test or during an infusion of sympathicomimetic drugs like Isoproterenol, aided by the identification of mutations in the RyR2 and CASQ2 genes through gene analysis. Implantable cardiodefibrillator devices remain a valid therapeutic option in many cases due to the fact that antiarrhythmic drugs have not shown efficacy. Sympathetic cardiac denervation can be useful in some special cases. Catecholaminergic Polymorphic Ventricular Tachycardia opens a wide field for the development of new antiarrhythmic drugs and the use of gene therapy for cardiac rhythm disorders.

  6. Wall Art

    Science.gov (United States)

    McGinley, Connie Q.

    2004-01-01

    The author of this article, an art teacher at Monarch High School in Louisville, Colorado, describes how her experience teaching in a new school presented an exciting visual challenge for an art teacher--monotonous brick walls just waiting for decoration. This school experienced only minimal instances of graffiti, but as an art teacher, she did…

  7. What is the clinical significance of ventricular mural antagonism?

    DEFF Research Database (Denmark)

    Lunkenheimer, Paul P; Niederer, Peter; Stephenson, Robert S

    2018-01-01

    Recent morphological studies provide evidence that the ventricular walls are arranged as a 3D meshwork of aggregated cardiomyocyte chains, exhibiting marked local structural variations. In contrary to previous findings, up to two-fifths of the chains are found to have a partially transmural align...... disease, such as hypertrophy and fibrosis. ß-blockade at low dosage acts selectively to temper the auxotonic forces....

  8. 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....

  9. Right ventricular function during acute exacerbation of severe equine asthma.

    Science.gov (United States)

    Decloedt, A; Borowicz, H; Slowikowska, M; Chiers, K; van Loon, G; Niedzwiedz, A

    2017-09-01

    Pulmonary hypertension has been described in horses with severe equine asthma, but its effect on the right ventricle has not been fully elucidated. To evaluate right ventricular structure and function after a 1-week period of pulmonary hypertension secondary to acute exacerbation of severe equine asthma. Prospective study. A clinical episode of severe equine asthma was induced experimentally in six susceptible horses. Examinations in remission and on day 7 of the clinical episode included a physical examination with clinical scoring, echocardiography, arterial blood gas measurements, venous blood sampling for cardiac biomarkers, intracardiac pressure measurements, right ventricular and right atrial myocardial biopsies, airway endoscopy and bronchoalveolar lavage. After 1 month of recovery, physical examination, echocardiography and cardiac biomarker analysis were repeated. Echocardiographic and pressure measurements were compared with those in 10 healthy control horses. All horses developed clinical signs of acute pulmonary obstruction. Right heart pressures increased significantly. Altered right ventricular function could be detected by tissue Doppler and speckle tracking echocardiography. Cardiac troponin concentrations did not increase significantly, but were highly elevated in one horse which exercised in the paddock prior to sampling. Focal neutrophil infiltration was present in two myocardial samples. Even in remission, asthmatic horses showed a thicker right ventricular wall, an increased left ventricular end-systolic eccentricity index at chordal level and decreased right ventricular longitudinal strain compared with controls. The induced clinical episode was rather mild and the number of horses was limited because of the invasive nature of the study. Pulmonary obstruction in asthmatic horses induces pulmonary hypertension with right ventricular structural and functional changes. © 2017 EVJ Ltd.

  10. Right ventricular failure following chronic pressure overload is associated with reduction in left ventricular mass: evidence for atrophic remodeling.

    Science.gov (United States)

    Hardziyenka, Maxim; Campian, Maria E; Reesink, Herre J; Surie, Sulaiman; Bouma, Berto J; Groenink, Maarten; Klemens, Christine A; Beekman, Leander; Remme, Carol A; Bresser, Paul; Tan, Hanno L

    2011-02-22

    We sought to study whether patients with right ventricular failure (RVF) secondary to chronic thromboembolic pulmonary hypertension (CTEPH) have reduced left ventricular (LV) mass, and whether LV mass reduction is caused by atrophy. The LV in patients with CTEPH is underfilled (unloaded). LV unloading may cause atrophic remodeling that is associated with diastolic and systolic dysfunction. We studied LV mass using cardiac magnetic resonance imaging (MRI) in 36 consecutive CTEPH patients (before/after pulmonary endarterectomy [PEA]) and 11 healthy volunteers selected to match age and sex of patients. We studied whether LV atrophy is present in monocrotaline (MCT)-injected rats with RVF or controls by measuring myocyte dimensions and performing in situ hybridization. At baseline, CTEPH patients with RVF had significantly lower LV free wall mass indexes than patients without RVF (35 ± 6 g/m(2) vs. 44 ± 7 g/m(2), p = 0.007) or volunteers (42 ± 6 g/m(2), p = 0.006). After PEA, LV free wall mass index increased (from 38 ± 6 g/m(2) to 44 ± 9 g/m(2), p = 0.001), as right ventricular (RV) ejection fraction improved (from 31 ± 8% to 56 ± 12%, p < 0.001). Compared with controls, rats with RVF had reduced LV free wall mass and smaller LV free wall myocytes. Expression of atrial natriuretic peptide was higher, whereas that of α-myosin heavy chain and sarcoplasmic reticulum calcium ATPase-2 were lower in RVF than in controls, both in RV and LV. RVF in patients with CTEPH is associated with reversible reduction in LV free wall mass. In a rat model of RVF, myocyte shrinkage due to atrophic remodeling contributed to reduction in LV free wall mass. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  11. A computationally efficient electrophysiological model of human ventricular cells

    NARCIS (Netherlands)

    Bernus, O.; Wilders, R.; Zemlin, C. W.; Verschelde, H.; Panfilov, A. V.

    2002-01-01

    Recent experimental and theoretical results have stressed the importance of modeling studies of reentrant arrhythmias in cardiac tissue and at the whole heart level. We introduce a six-variable model obtained by a reformulation of the Priebe-Beuckelmann model of a single human ventricular cell. The

  12. Outcome of Treatment of Anterior Vaginal Wall Prolapse and Stress Urinary Incontinence with Transobturator Tension-Free Vaginal Mesh (Prolift and Concomitant Tension-Free Vaginal Tape-Obturator

    Directory of Open Access Journals (Sweden)

    Sameh Azazy

    2008-12-01

    Full Text Available Objective. It is to assess the feasibility, effectiveness, and safety of transobturator tension-free vaginal mesh (Prolift and concomitant tension-free vaginal tape-obturator (TVT-O system as a treatment of female anterior vaginal wall prolapse associated with stress urinary incontinence (SUI. Patients and Methods. Between December 2006 and July 2007, 20 patients with anterior genital prolapse and voiding dysfunction were treated with the transobturator tension-free vaginal mesh (Prolift and concomitant tension-free vaginal tape-obturator (TVT-O. Sixteen patients had stress urinary incontinence and 4 patients were considered at risk for development of de novo stress incontinence after the prolapse is repaired. All patients underwent a complete urodynamic assessment. All the patients underwent pelvic examination 4–6 weeks after the operation, and anatomical and functional outcomes were recorded. Results. Twenty cystocoeles were repaired: 6 grade II, 12 grade III, and 2 grade IV. There were no vessel or bladder injuries. Eighteen patients had optimal anatomic results and 2 patients had persistent asymptomatic stage I prolapse. Conclusion. These preliminary results suggest that Prolift system offers a safe and effective treatment for female anterior vaginal wall prolapse. However, a long-term followup is necessary in order to support the good result maintenance.

  13. Isolated congenital cardiac diverticulum originating from the left ventricular apex: Report of a pediatric case

    Directory of Open Access Journals (Sweden)

    Fahrettin Uysal

    2016-01-01

    Full Text Available Congenital ventricular diverticulum is a rare cardiac anomaly defined as a localized protrusion of the ventricular free wall. Although, it is usually asymptomatic, complications such as embolism, infective endocarditis, and arrhythmias can occur. The diagnosis can be made by echocardiography, cardiac magnetic resonance imaging, or catheter angiography. Surgical resection is the treatment of choice in symptomatic patients, whereas the management of asymptomatic patients often represents a therapeutic dilemma. We report here, a 9-month-old patient with asymptomatic congenital left ventricular (LV diverticulum associated with epigastric hernia.

  14. Complications during pharmacological stress echocardiography: a video-case series

    Directory of Open Access Journals (Sweden)

    Bigi Riccardo

    2005-09-01

    Full Text Available Abstract Background Stress echocardiography is a cost-effective tool for the modern noninvasive diagnosis of coronary artery disease. Several physical and pharmacological stresses are used in combination with echocardiographic imaging, usually exercise, dobutamine and dipyridamole. The safety of a stress is (or should be a major determinant in the choice of testing. Although large scale single center experiences and multicenter trial information are available for both dobutamine and dipyridamole stress echo testing, complications or side effects still can occur even in the most experienced laboratories with the most skilled operators. Case presentation We decided to present a case collection of severe complications during pharmacological stress echo testing, including a ventricular tachycardia, cardiogenic shock, transient ischemic attack, torsade de pointe, fatal ventricular fibrillation, and free wall rupture. Conclusion We believe that, in this field, every past complication described is a future complication avoided; what happens in your lab is more true of what you read in journals; and Good Clinical Practice is not "not having complications", but to describe the complications you had.

  15. Case report: paradoxical ventricular septal motion in the setting of primary right ventricular myocardial failure.

    Science.gov (United States)

    Maslow, Andrew; Schwartz, Carl; Mahmood, Feroze; Singh, Arun; Heerdt, Paul M

    2009-07-01

    In this report, a case of right ventricular (RV) failure, hemodynamic instability, and systemic organ failure is described to highlight how paradoxical ventricular systolic septal motion (PVSM), or a rightward systolic displacement of the interventricular septum, may contribute to RV ejection. Multiple inotropic medications and vasopressors were administered to treat right heart failure and systemic hypotension in a patient following combined aortic and mitral valve replacement. In the early postoperative period, echocardiographic evaluation revealed adequate left ventricular systolic function, akinesis of the RV myocardial tissues, and PVSM. In the presence of PVSM, RV fractional area of contraction was > or =35% despite akinesis of the primary RV myocardial walls. The PVSM appeared to contribute toward RV ejection. As a result, the need for multiple inotropes was re-evaluated, in considering that end-organ dysfunction was the result of systemic hypotension and prolonged vasopressor administration. After discontinuation of phosphodiesterase inhibitors, native vascular tone returned and the need for vasopressors declined. This was followed by recovery of systemic organ function. Echocardiographic re-evaluation two years later, revealed persistent akinesis of the RV myocardial tissues and PVSM, the latter appearing to contribute toward RV ejection. This case highlights the importance of left to RV interactions, and how PVSM may mediate these hemodynamic interactions.

  16. Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

    Directory of Open Access Journals (Sweden)

    A. Schmidt

    2001-07-01

    Full Text Available To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter. In each study, dobutamine (5 to 40 µg kg-1 min-1 in 3-min stages and pacing (20 bpm increments, each 2 min, up to 260 bpm were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min. The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05 reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery. Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1 the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2 in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 ± 11% and dipyridamole (-18 ± 16% tests as compared to dobutamine (-9 ± 6% (P = 0.05, but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery (pacing: -16 ± 7%; dipyridamole: -25 ± 16%; dobutamine: -26 ± 10%; not significant, and 3 a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery

  17. Ventricular septal defect.

    Science.gov (United States)

    Giboney, G S

    1983-05-01

    This article has discussed the ventricular septal defect, its occurrence, physiology, and therapy, and nursing concerns. The VSD, a communication allowing left-to-right shunting of blood at the ventricular level, is the most common congenital heart defect. Surgical correction is often required for large defects before the age of 12 months, and primary correction is now considered standard procedure. Small defects usually close spontaneously, and moderate defects are closely monitored for signs indicating the need for surgical intervention. Nursing care begins with child and family assessment and evaluation of the strengths and weaknesses of the family system. The child's developmental level is a major consideration in formulating interventions for his benefit. Play therapy is a useful vehicle in relating to the child in a nonthreatening manner preoperatively and in allowing the child to work through his hospitalization postoperatively. Maintaining the physical integrity of a child just out of the operating room is a challenge. Continuing support of the family system is a significant aspect of nursing's responsibility toward child and family. Discharge planning and intervention strive to prepare the family for the transition from hospital to home both physically and emotionally.

  18. Right ventricular metastasis of leiomyosarcoma

    Directory of Open Access Journals (Sweden)

    Stagmo Martin

    2009-05-01

    Full Text Available Abstract Metastatic presentation of leiomyosarcoma in the heart is very rare. We present transthoracic echocardiography and combined PET/CT images of a case with a large right ventricular metastasis of leiomyosarcoma. The patient was placed on cytostatic drugs for palliative purposes, but passed away one month later because of an untreatable ventricular tackycardia.

  19. Idiopathic Fascicular Left Ventricular Tachycardia.

    Science.gov (United States)

    Alahmad, Yaser; Asaad, Nidal Ahmad; Arafa, Salaheddin Omran; Ahmad Khan, Shahul Hameed; Mahmoud, Alsayed

    2017-01-01

    Idiopathic left fascicular ventricular tachycardia (ILFVT) is characterized by right bundle branch block morphology and left axis deviation. We report a case of idiopathic left ventricular fascicular tachycardia in a young 31-year-old male patient presenting with a narrow complex tachycardia.

  20. Idiopathic Fascicular Left Ventricular Tachycardia

    OpenAIRE

    Alahmad, Yaser; Asaad, Nidal Ahmad; Arafa, Salaheddin Omran; Ahmad Khan, Shahul Hameed; Mahmoud, Alsayed

    2017-01-01

    Idiopathic left fascicular ventricular tachycardia (ILFVT) is characterized by right bundle branch block morphology and left axis deviation. We report a case of idiopathic left ventricular fascicular tachycardia in a young 31-year-old male patient presenting with a narrow complex tachycardia.

  1. Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study

    Directory of Open Access Journals (Sweden)

    Liu Biyue

    2012-07-01

    Full Text Available Abstract Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS acting tangentially to the wall, and the wall pressure (WP acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT with wall pressure (WP, blood pressure on the lumen wall and spatial wall pressure gradient (WPG in a human atherosclerotic right coronary artery were studied. The pulsatile blood flow was simulated using a three dimensional mathematical model. The blood was treated as an incompressible viscous non-Newtonian fluid. The geometry of the artery was re-constructed using an in vivo intravascular ultrasound (IVUS 44-slice dataset obtained from a patient with consent obtained. The WT, the WP and the WPG were averaged on each slice, respectively, and Pearson correlation analysis was performed on slice averaged base. Each slice was then divided into 8 segments and averaged vessel WT, WP and WPG were collected from all 352 segments for correlation analysis. Each slice was also divided into 2 segments (inner semi-wall of bend and outer semi-wall of bend and the correlation analysis was performed on the 88 segments. Results Under mean pressure, the Pearson coefficient for correlation between WT and WP was r = − 0.52 (p  Conclusions Results from this representative case report indicated that plaque wall thickness correlated negatively with wall pressure (r = −0.81 by slice and positively with wall pressure gradient (r = 0.45. The slice averaged WT has a strong linear relationship with the slice averaged WP. Large-scale patient studies are needed to further confirm our findings.

  2. Hemodialysis-Induced Regional Left Ventricular Systolic Dysfunction: Prevalence, Patient and Dialysis Treatment-Related Factors, and Prognostic Significance

    Science.gov (United States)

    Assa, Solmaz; Hummel, Yoran M.; Voors, Adriaan A.; Kuipers, Johanna; Westerhuis, Ralf; de Jong, Paul E.

    2012-01-01

    Summary Background and objectives The hemodialysis procedure may acutely induce regional left ventricular systolic dysfunction. This study evaluated the prevalence, time course, and associated patient- and dialysis-related factors of this entity and its association with outcome. Design, setting, participants, & measurements Hemodialysis patients (105) on a three times per week dialysis schedule were studied between March of 2009 and March of 2010. Echocardiography was performed before dialysis, at 60 and 180 minutes intradialysis, and at 30 minutes postdialysis. Hemodialysis-induced regional left ventricular systolic dysfunction was defined as an increase in wall motion score in more than or equal to two segments. Results Hemodialysis-induced regional left ventricular systolic dysfunction occurred in 29 (27%) patients; 17 patients developed regional left ventricular systolic dysfunction 60 minutes after onset of dialysis. Patients with hemodialysis-induced left ventricular systolic dysfunction were more often male, had higher left ventricular mass index, and had worse predialysis left ventricular systolic function (left ventricular ejection fraction). The course of blood volume, BP, heart rate, electrolytes, and acid–base parameters during dialysis did not differ significantly between the two groups. Patients with hemodialysis-induced regional left ventricular systolic dysfunction had a significantly higher mortality after correction for age, sex, dialysis vintage, diabetes, cardiovascular history, ultrafiltration volume, left ventricular mass index, and predialysis wall motion score index. Conclusions Hemodialysis induces regional wall motion abnormalities in a significant proportion of patients, and these changes are independently associated with increased mortality. Hemodialysis-induced regional left ventricular systolic dysfunction occurs early during hemodialysis and is not related to changes in blood volume, electrolytes, and acid–base parameters. PMID

  3. Salubrinal attenuates right ventricular hypertrophy and dysfunction in hypoxic pulmonary hypertension of rats.

    Science.gov (United States)

    He, Yun-Yun; Liu, Chun-Lei; Li, Xin; Li, Rui-Jun; Wang, Li-Li; He, Kun-Lun

    2016-12-01

    The phosphorylation of eukaryotic translation initiation factor 2 alpha (p-eIF2α) is essential for cell survival during hypoxia. The aim of this study was to investigate whether salubrinal, an inhibitor of p-eIF2α dephosphorylation could attenuate pulmonary arterial hypertension (PAH) and right ventricular (RV) hypertrophy in rats exposed to hypobaric hypoxia. PAH of rats was induced by hypobaric hypoxia. Salubrinal supplemented was randomized in either a prevention or a reversal protocol. At the end of the follow-up point, we measured echocardiography, hemodynamics, hematoxylin-eosin and Masson's trichrome stainings. RNA-seq analysis is explored to identify changes in gene expression associated with hypobaric hypoxia with or without salubrinal. Compared with vehicle-treatment rats exposed to hypobaric hypoxia, salubrinal prevented and partly reversed the increase of the mean pulmonary artery pressure and RV hypertrophy. What's more, salubrinal reduced the percentage wall thickness (WT%) of pulmonary artery and RV collagen volume fraction (CVF) in both prevention and reversal protocols. We also found that salubrinal was capable of reducing endoplasmic reticulum stress and oxidative stress. The result of RNA-seq analysis revealed that chronic hypoxia stimulated the differential expression of a series of genes involved in cell cycle regulation and ventricular hypertrophy and so on. Some of these genes could be ameliorated by salubrinal. These results indicate that salubrinal could prevent and reverse well-established RV remodeling, and restore the genes and pathways altered in the right ventricles of rats exposed to hypobaric hypoxia. Copyright © 2016. Published by Elsevier Inc.

  4. 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...

  5. Wall Layers

    Science.gov (United States)

    1992-01-14

    Sydney, Australia. December 6, 1990. Lumley, J. L. A dynamical-systems-theory approach to the wall region. Environmental Engineering Laboratory, CSIRO...Nonlinear Science. Holmes, P. Editor in Chief, Nonlinear Scinece Today. Holmes, P. Reviewer for Physica D, J. Sound Vib., J. Phys., Q. Appl. Math, Phys...Spring, 1994; Organizing committee member. Holmes, P. Editorial Board Member: Archive for Rational Mechanics and Analysis; Journal of Nonlinear Scinece

  6. CLIMBING WALL

    CERN Multimedia

    1999-01-01

    The FIRE AND RESCUE Group of TIS Commission informs that the climbing wall in the yard of the Fire-fighters Station, is intended for the sole use of the members of that service, and recalls that access to this installation is forbidden for safety reasons to all persons not belonging to the Service.CERN accepts no liability for damage or injury suffered as a result of failure to comply with this interdiction.TIS/DI

  7. [Not isolated ventricular compaction in an infant].

    Science.gov (United States)

    Dibi, A; Jabourik, F; Bentahila, A

    2016-04-01

    Not isolated ventricular compaction cardiomyopathy is a rare deasese described both in children than in adults. It due to the interruption of the embryogenic compaction process of the normal myocardium. We report a pediatric observation of noncompaction of the left ventricle. This is a 4-month girl who was admitted to an array of heart failure with systolic murmur to FM. Chest radiography showed cardiomegaly. The ECG showed repolarization disorder. The echocardiography objectified dilated left cavities with thickened wall and anechoic areas (sinusoidal), a mitral regurgitation GII and minimal tricuspid regurgitation. NCVI is a rare cause of heart failure in infants. The management is based on guidelines for various clinical symptomatology. Its discovery in children should lead to screening of first-degree relative. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. Prognostic Value of Normal Perfusion but Impaired Left Ventricular Function in the Diabetic Heart on Quantitative Gated Myocardial Perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hwanjeong; Choi, Sehun; Han, Yeonhee [Research Institute of Chonbuk National Univ. Medical School and Hospitial, Jeonju (Korea, Republic of); Lee, Dong Soo; Lee, Hoyoung; Chung, Junekey [Seoul National Univ., Seoul (Korea, Republic of)

    2013-09-15

    This study aimed at identifying the predictive parameters on quantitative gated myocardial perfusion single-photon emission computed tomography (QG-SPECT) in diabetic patients with normal perfusion but impaired function. Methods Among the 533 consecutive diabetic patients, 379 patients with normal perfusion on rest Tl-201/dipyridamole-stress Tc-{sup 99m} sestamibi Gated SPECT were enrolled. Patients were grouped into those with normal post-stress left ventricular function (Group I) and those with impaired function (EF <50 or impaired regional wall motion, Group II). We investigated cardiac events and cause of death by chart review and telephone interview. Survival analysis and Cox proportional hazard model analysis were performed. Between the Group I and II, cardiac events as well as chest pain symptoms, smoking, diabetic complications were significantly different (P<0.05). On survival analysis, event free survival rate in Group II was significantly lower than in Group I (P=0.016). In univariate Cox proportional hazard analysis on overall cardiac event, Group (II over I), diabetic nephropathy, summed motion score (SMS), summed systolic thickening score (STS), numbers of abnormal segmental wall motion and systolic thickening predicted more cardiac events (P<0.05). Multivariate analysis showed that STS was the only independent predictor cardiac event. The functional parameter, especially summed systolic thickening score on QG-SPECT had prognostic values, despite normal perfusion, in predicting cardiac events in diabetic patients, and QG-SPECT provides clinically useful risk stratification in diabetic patients with normal perfusion.

  9. [Late potentials and ventricular arrhythmia].

    Science.gov (United States)

    Adamec, R; Zimmermann, M

    1986-04-01

    When electrodes are placed at the surface of the thorax, high-amplification electrocardiography (HA-ECG) combined with signal summation as a function of time provides a non-invasive method for detecting electric potentials occurring after the QRS complex of the clinical electrocardiogram. These potentials are called late, and can probably be likened to the "divided" or "fragmented" potentials recorded directly on the heart or in its ventricles near zones of ischemia, infarction or aneurysm. The prevalence of late potentials of ventricular activation (LPVA) and their association with the occurrence of ventricular arrhythmias seems well established, notably in the presence of ventricular aneurysm and anamnesis of severe ventricular arrhythmia. Some studies have shown that detection of LPVAs is of value in identifying heart patients at risk of ventricular arrhythmia or sudden death. Heart disease aside, the presence of LPVAs has been demonstrated in arrhythmogenic right ventricular dysplasia and reported in Fallot's tetralogy after complete correction. A standardization of recordings and a more precise definition of LPVAs are necessary before HA-ECG can become a routine clinical method. Further, the possibility of "beat by beat" recordings with "spatial" summation will allow detection of LPVAs which vary with time and in nature and hence provide a better understanding of the genesis of ventricular arrhythmias.

  10. Effects of 6-month treatment with the glucagon like peptide-1 analogue liraglutide on arterial stiffness, left ventricular myocardial deformation and oxidative stress in subjects with newly diagnosed type 2 diabetes.

    Science.gov (United States)

    Lambadiari, Vaia; Pavlidis, George; Kousathana, Foteini; Varoudi, Maria; Vlastos, Dimitrios; Maratou, Eirini; Georgiou, Dimitrios; Andreadou, Ioanna; Parissis, John; Triantafyllidi, Helen; Lekakis, John; Iliodromitis, Efstathios; Dimitriadis, George; Ikonomidis, Ignatios

    2018-01-08

    Incretin-based therapies are used in the treatment of type 2 diabetes mellitus (T2DM) and obesity. We investigated the changes in arterial stiffness and left ventricular (LV) myocardial deformation after 6-month treatment with the GLP-1 analogue liraglutide in subjects with newly diagnosed T2DM. We randomized 60 patients with newly diagnosed and treatment-naive T2DM to receive either liraglutide (n = 30) or metformin (n = 30) for 6 months. We measured at baseline and after 6-month treatment: (a) carotid-femoral pulse wave velocity (PWV) (b) LV longitudinal strain (GLS), and strain rate (GLSR), peak twisting (pTw), peak twisting velocity (pTwVel) and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography. LV untwisting was calculated as the percentage difference between peak twisting and untwisting at MVO (%dpTw-Utw MVO ), at peak (%dpTw-Utw PEF ) and end of early LV diastolic filling (%dpTw-Utw EDF ) (c) Flow mediated dilatation (FMD) of the brachial artery and percentage difference of FMD (FMD%) (d) malondialdehyde (MDA), protein carbonyls (PCs) and NT-proBNP. After 6-months treatment, subjects that received liraglutide presented with a reduced PWV (11.8 ± 2.5 vs. 10.3 ± 3.3 m/s), MDA (0.92 [0.45-2.45] vs. 0.68 [0.43-2.08] nM/L) and NT-proBNP (p < 0.05) in parallel with an increase in GLS (- 15.4 ± 3 vs. - 16.6 ± 2.7), GLSR (0.77 ± 0.2 vs. 0.89 ± 0.2), pUtwVel (- 97 ± 49 vs. - 112 ± 52°, p < 0.05), %dpTw-Utw MVO (31 ± 10 vs. 40 ± 14), %dpTw-Utw PEF (43 ± 19 vs. 53 ± 22) and FMD% (8.9 ± 3 vs. 13.2 ± 6, p < 0.01). There were no statistically significant differences of the measured markers in subjects that received metformin except for an improvement in FMD. In all subjects, PCs levels at baseline were negatively related to the difference of GLS (r = - 0.53) post-treatment and the difference of MDA was associated with the difference of PWV (r = 0.52) (p < 0.05 for all associations

  11. Fast domain wall dynamics in amorphous and nanocrystalline magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Varga, R., E-mail: rvarga@upjs.sk [Institute of Physics, Faculty of Science, UPJS, Park Angelinum 9, 041 54, Kosice (Slovakia); Klein, P.; Richter, K. [Institute of Physics, Faculty of Science, UPJS, Park Angelinum 9, 041 54, Kosice (Slovakia); Zhukov, A. [Dept. Fisica de Materiales, Fac. Quimica, UPV/EHU, San Sebastian (Spain); Vazquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, 28049 Cantoblanco, Madrid (Spain)

    2012-10-15

    We have studied the effect of thermal treatment on the domain wall dynamics of FeSiB and FeCoMoB microwires. It was shown that annealing in transversal magnetic field increases the domain wall mobility as well as the domain wall velocity. Annealing under the tensile stress hinders the appearance of the monodomain structure but application of tensile stress leads to the magnetic bistability having the domain wall mobility twice higher that in as-cast state. Further increase of the tensile stress reduces the domain wall mobility but the domain wall velocity increases as a result of the decrease of critical propagation field. Annealing of the FeCoMoB microwire by Joule heating leads to introduction of the circular anisotropy that favors the vortex domain wall. Such treatment increases the domain wall mobility as well as the maximum domain wall velocity.

  12. 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

  13. Basal cardiomyopathy develops in rabbits with ventricular tachyarrhythmias induced by a single injection of adrenaline.

    Science.gov (United States)

    Ashida, Terunao; Takato, Tetsuya; Matsuzaki, Gen; Seko, Yoshinori; Fujii, Jun; Kawai, Sachio

    2014-01-01

    We have recently demonstrated that basal cardiomyopathy develops in rabbits with ventricular tachyarrhythmias that have been induced by electrical stimulation of the cervical vagus. This study investigated whether similar basal cardiomyopathy would develop in rabbits with ventricular tachyarrhythmias induced by a single injection of adrenaline. Adrenaline was intravenously infused for 10-360 seconds in anesthetized rabbits. Colloidal carbon was injected after adrenaline infusion. Wall movement velocity of the left ventricular base was assessed by tissue Doppler echocardiography. Animals were killed either 1 week or 3-4 weeks later. Pathological lesions were identified by deposits of carbon particles. Animals were divided into two groups according to the infused dose of adrenaline. The small-dose group (group S, n = 15) received 1-10 μg and the large-dose group (group L, n = 23) received 15-60 μg of adrenaline. Adrenaline infusion induced premature ventricular contractions followed by monomorphic ventricular tachycardias in 22 of 23 animals in group L, but in only 1 of 15 animals in group S. Wall movement velocity of the left ventricular base decreased just after adrenaline infusion, remained low after 1 week, and recovered to near-baseline levels after 3-4 weeks in group L. Unique cardiac lesions identified by deposits of carbon particles were frequently observed on the left ventricular basal portion, almost always associated with the mitral valve and papillary muscles, but were never observed in the apical area. Lesions involving all areas of the left ventricular basal portion were observed in 22 of 23 animals in group L, but in only 2 of 15 animals in group S. Basal cardiomyopathy developed in rabbits with ventricular tachycardias induced by a single injection of adrenaline.

  14. Normal Coronary Artery Patient Presenting with Left Ventricular Aneurysm

    Directory of Open Access Journals (Sweden)

    Hakan Altay

    2011-01-01

    Full Text Available Left ventricular aneurysm (LVA is one of the most important complications of myocardial infarction LVA is strictly defined as a distinct area of abnormal left ventricular diastolic contour with systolic dyskinesia or paradoxical bulging. LVA usually results from myocardial infarction. Other rare aetiologies of LVA include hypertrophic cardiomyopathy, Chagas' disease, sarcoidosis, congenital LVA, and idiopathic However, LVA formation in patients with idiopathic dilated cardiomyopathy is rarely reported, and the incidence, clinical features, and pathogenesis of LVA formation in patients with idiopathic dilated cardiomyopathy is not well understood. Here, we present a 45 years old, idiopathic dilated cardiomyopathy patient with LVA and normal coronary arteries The pathogenesis of LVA formation in patients with idiopathic dilated cardiomyopathy is not clear. One acceptable hypothesis is that coronary artery emboli originate from mural thrombi, present in some patients with idiopathic dilated cardiomyopathy, which develop due to local wall infarction and fibrosis. The local myocardial perfusion differences could be seen in idiopathic dilated cardiomyopathy and predominantly found in the anteroposterior axis of the left ventricle. Local fibrosis occurs more frequently on the anterior wall or posterior wall, and less frequently on the lateral or septal wall. In our patient, LVA existed in the septal segments.We could not define the exact mechanism of the septal aneurysm in our patient but we decided to present this abnormal case, which is different from cases thus far reported in the literature.

  15. Prediction of Residual Stress Distributions in Welded Sections of P92 Pipes with Small Diameter and Thick Wall based on 3D Finite Element Simulation

    Science.gov (United States)

    Wang, Xiaowei; Gong, Jianming; Zhao, Yanping; Wang, Yanfei

    2015-05-01

    This study used ABAQUS finite element (FE) software to investigate the residual stress distributions of P92 welded pipes in both the as-weld and post weld heat treated (PWHT) condition. Sequential coupling quasi-static thermo-mechanical in conjunction with moving double ellipsoidal heat source and an element add/remove technique to simulate deposition of new weld material, are combined in the 3D FE analysis. To validate the simulation results, the residual stresses in axial direction at the surface of pipe were measured by X-ray diffraction technique and compared with the results of FE analysis. Detailed characteristic distributions of the residual stresses are discussed. Results show that the FE model can predict the residual stress distributions satisfactorily. Highest residual stresses on the outer surface are found in the last weld bead to be deposited. And the highest tensile residual stress for the full welded section take place in heat affected zone (HAZ) near the middle thickness. Larger residual sstress can be found around the welding start point along the pipe circumference. Comparison of heat treated specimen and untreated specimen illustrates that PWHT has a strong effect on the residual stress field.

  16. Atrial and ventricular function in thalassemic patients with supraventricular arrhythmias

    Directory of Open Access Journals (Sweden)

    Vitantonio Di Bello

    2009-04-01

    Full Text Available The aims of this study were to evaluate through Color Doppler Myocardial Imaging (CDMI echocardiography if atrial or ventricular myocardial alterations could be detectable in patients with thalassemia major (THAL and if these alterations could be considered as predictive elements for supra-ventricular arrhythmic events. Twenty-three patients with THAL underwent clinical and electrocardiographic evaluation; patients were grouped in THAL1 (9 with supra-ventricular arrhythmias and THAL2 (14 without arrhythmias; 12 healthy subjects were considered as control group (C. We examined through conventional 2D Color Doppler echocardiography some morphological and functional parameters regarding left ventricular (LV systolic and diastolic function, and through CDMI the velocities at mitral annulus level, the regional LV and left atrial (LA strain and strain rate. All THAL patients had LV dimension (pless than 0.05, LA area (p less than 0.01 and E/Em ratio (pless than 0.001 to be significantly higher than controls. The mitral annulus longitudinal velocities were significantly lower in THAL1 than in THAL2 (pless than 0.001; the E/Em ratio was higher in THAL1 than THAL2 (pless than 0.001. The THAL1 showed a lower systolic strain rate of atrial wall than THAL2 and C (pless than 0.05. The multiple regression highlighted a significantly inverse correlation among E/Em and atrial strain (pless than 0.02. CDMI showed both THAL subgroups had subtle systolic and diastolic left ventricular myocardial alterations, which could represent the onset of developing “iron cardiomyopathy” and are related to supra-ventricular arrhythmia. Monitoring these parameters in the THAL patients could contribute to decisions about follow-up and therapy.

  17. Computer simulation of ECG manifestations of left ventricular electrical remodeling.

    Science.gov (United States)

    Bacharova, Ljuba; Szathmary, Vavrinec; Potse, Mark; Mateasik, Anton

    2012-01-01

    An increased QRS voltage is considered to be specific for the electrocardiogram (ECG) diagnosis of left ventricular hypertrophy (LVH). However, the QRS-complex patterns in patients with LVH cover a broader spectrum: increased QRS voltage, prolonged QRS duration, left axis deviation, and left anterior fascicular block- and left bundle branch block-like patterns, as well as pseudo-normal QRS patterns. The classical interpretation of the QRS patterns in LVH relates these changes to increased left ventricular mass (LVM) per se, while tending to neglect the modified active and passive electrical properties of the myocardium. However, it has been well documented that both active and passive electrical properties in LVH are altered. Using computer simulations, we have shown that an increased LVM is not the only determinant of QRS complex changes in LVH, as these changes could also be produced without changing the left ventricular mass, implying that these QRS patterns can be present in patients before their LVM exceeds the arbitrary upper normal limits. Our results link the experimental evidence on electrical remodeling with clinical interpretation of ECG changes in patients with LVH and stress the necessity of a complex interpretation of the QRS patterns considering both spatial and nonspatial determinants in terms of the spatial angle theory. We assume that hypertrophic electrical remodeling in combination with changes in left ventricular size and shape explains the variety of ECG patterns as well as the discrepancies between ECG and left ventricular mass. Copyright © 2012 Elsevier Inc. All rights reserved.