WorldWideScience

Sample records for stress cardiovascular magnetic

  1. Adenosine stress cardiovascular magnetic resonance with variable-density spiral pulse sequences accurately detects coronary artery disease: initial clinical evaluation.

    Science.gov (United States)

    Salerno, Michael; Taylor, Angela; Yang, Yang; Kuruvilla, Sujith; Ragosta, Michael; Meyer, Craig H; Kramer, Christopher M

    2014-07-01

    Adenosine stress cardiovascular magnetic resonance perfusion imaging can be limited by motion-induced dark-rim artifacts, which may be mistaken for true perfusion abnormalities. A high-resolution variable-density spiral pulse sequence with a novel density compensation strategy has been shown to reduce dark-rim artifacts in first-pass perfusion imaging. We aimed to assess the clinical performance of adenosine stress cardiovascular magnetic resonance using this new perfusion sequence to detect obstructive coronary artery disease. Cardiovascular magnetic resonance perfusion imaging was performed during adenosine stress (140 μg/kg per minute) and at rest on a Siemens 1.5-T Avanto scanner in 41 subjects with chest pain scheduled for coronary angiography. Perfusion images were acquired during injection of 0.1 mmol/kg Gadolinium-diethylenetriaminepentacetate at 3 short-axis locations using a saturation recovery interleaved variable-density spiral pulse sequence. Significant stenosis was defined as >50% by quantitative coronary angiography. Two blinded reviewers evaluated the perfusion images for the presence of adenosine-induced perfusion abnormalities and assessed image quality using a 5-point scale (1 [poor] to 5 [excellent]). The prevalence of obstructive coronary artery disease by quantitative coronary angiography was 68%. The average sensitivity, specificity, and accuracy were 89%, 85%, and 88%, respectively, with a positive predictive value and negative predictive value of 93% and 79%, respectively. The average image quality score was 4.4±0.7, with only 1 study with more than mild dark-rim artifacts. There was good inter-reader reliability with a κ statistic of 0.67. Spiral adenosine stress cardiovascular magnetic resonance results in high diagnostic accuracy for the detection of obstructive coronary artery disease with excellent image quality and minimal dark-rim artifacts. © 2014 American Heart Association, Inc.

  2. Isometric stress in cardiovascular magnetic resonance - a simple and easily replicable method of assessing cardiovascular differences not apparent at rest

    International Nuclear Information System (INIS)

    Mortensen, Kristian H.; Jones, Alexander; Steeden, Jennifer A.; Taylor, Andrew M.; Muthurangu, Vivek

    2016-01-01

    Isometric exercise may unmask cardiovascular disease not evident at rest, and cardiovascular magnetic resonance (CMR) imaging is proven for comprehensive resting assessment. This study devised a simple isometric exercise CMR methodology and assessed the hemodynamic response evoked by isometric exercise. A biceps isometric exercise technique was devised for CMR, and 75 healthy volunteers were assessed at rest, after 3-minute biceps exercise, and 5-minute of recovery using: (1) blood pressure (BP) and (2) CMR measured aortic flow and left ventricular function. Total peripheral resistance (SVR) and arterial compliance (TAC), cardiac output (CO), left ventricular volumes and function (ejection fraction, stroke volume, power output), blood pressure (BP), heart rate (HR), and rate pressure product were assessed at all time points. Image quality was preserved during stress. During exercise there were increases in CO (+14.9 %), HR (+17.0 %), SVR (+9.8 %), systolic BP (+22.4 %), diastolic BP (+25.4 %) and mean BP (+23.2 %). In addition, there were decreases in TAC (-22.0 %) and left ventricular ejection fraction (-6.3 %). Age and body mass index modified the evoked response, even when resting measures were similar. Isometric exercise technique evokes a significant cardiovascular response in CMR, unmasking physiological differences that are not apparent at rest. (orig.)

  3. Isometric stress in cardiovascular magnetic resonance - a simple and easily replicable method of assessing cardiovascular differences not apparent at rest

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, Kristian H.; Jones, Alexander; Steeden, Jennifer A.; Taylor, Andrew M.; Muthurangu, Vivek [UCL Centre for Cardiovascular MR, UCL Institute of Cardiovascular Science, Level 6 Old Nurses Home, Cardiorespiratory Unit, Great Ormond Street Hospital for Children, London (United Kingdom)

    2016-04-15

    Isometric exercise may unmask cardiovascular disease not evident at rest, and cardiovascular magnetic resonance (CMR) imaging is proven for comprehensive resting assessment. This study devised a simple isometric exercise CMR methodology and assessed the hemodynamic response evoked by isometric exercise. A biceps isometric exercise technique was devised for CMR, and 75 healthy volunteers were assessed at rest, after 3-minute biceps exercise, and 5-minute of recovery using: (1) blood pressure (BP) and (2) CMR measured aortic flow and left ventricular function. Total peripheral resistance (SVR) and arterial compliance (TAC), cardiac output (CO), left ventricular volumes and function (ejection fraction, stroke volume, power output), blood pressure (BP), heart rate (HR), and rate pressure product were assessed at all time points. Image quality was preserved during stress. During exercise there were increases in CO (+14.9 %), HR (+17.0 %), SVR (+9.8 %), systolic BP (+22.4 %), diastolic BP (+25.4 %) and mean BP (+23.2 %). In addition, there were decreases in TAC (-22.0 %) and left ventricular ejection fraction (-6.3 %). Age and body mass index modified the evoked response, even when resting measures were similar. Isometric exercise technique evokes a significant cardiovascular response in CMR, unmasking physiological differences that are not apparent at rest. (orig.)

  4. Cardiovascular Reactivity, Stress, and Physical Activity

    Directory of Open Access Journals (Sweden)

    Chun-Jung eHuang

    2013-11-01

    Full Text Available Psychological stress has been proposed as a major contributor to the progression of cardiovascular disease (CVD. Acute mental stress can activate the sympathetic-adrenal-medullary (SAM axis, eliciting the release of catecholamines (NE and EPI resulting in the elevation of heart rate (HR and blood pressure (BP. Combined stress (psychological and physical can exacerbate these cardiovascular responses, which may partially contribute to the elevated risk of CVD and increased proportionate mortality risks experienced by some occupations (e.g., firefighting and law enforcement. Studies have supported the benefits of physical activity on physiological and psychological health, including the cardiovascular response to acute stress. Aerobically trained individuals exhibit lower sympathetic nervous system (e.g., HR reactivity and enhanced cardiovascular efficiency (e.g., lower vascular reactivity and decreased recovery time in response to physical and/or psychological stress. In addition, resistance training has been demonstrated to attenuate cardiovascular responses and improve mental health. This review will examine stress-induced cardiovascular reactivity and plausible explanations for how exercise training and physical fitness (aerobic and resistance exercise can attenuate cardiovascular responses to stress. This enhanced functionality may facilitate a reduction in the incidence of stroke and myocardial infarction. Finally, this review will also address the interaction of obesity and physical activity on cardiovascular reactivity and CVD.

  5. Dobutamine stress cardiovascular magnetic resonance at 3 Tesla

    Directory of Open Access Journals (Sweden)

    Klein C

    2008-10-01

    Full Text Available Abstract Purpose The assessment of inducible wall motion abnormalities during high-dose dobutamine-stress cardiovascular magnetic resonance (DCMR is well established for the identification of myocardial ischemia at 1.5 Tesla. Its feasibility at higher field strengths has not been reported. The present study was performed to prospectively determine the feasibility and diagnostic accuracy of DCMR at 3 Tesla for depicting hemodynamically significant coronary artery stenosis (≥ 50% diameter stenosis in patients with suspected or known coronary artery disease (CAD. Materials and methods Thirty consecutive patients (6 women (66 ± 9.3 years were scheduled for DCMR between January and May 2007 for detection of coronary artery disease. Patients were examined with a Philips Achieva 3 Tesla system (Philips Healthcare, Best, The Netherlands, using a spoiled gradient echo cine sequence. Technical parameters were: spatial resolution 2 × 2 × 8 mm3, 30 heart phases, spoiled gradient echo TR/TE: 4.5/2.6 msec, flip angle 15°. Images were acquired at rest and stress in accordance with a standardized high-dose dobutamine-atropine protocol during short breath-holds in three short and three long-axis views. Dobutamine was administered using a standard protocol (10 μg increments every 3 minutes up to 40 μg dobutamine/kg body weight/minute plus atropine if required to reach target heart rate. The study protocol included administration of 0.1 mmol/kg/body weight Gd-DTPA before the cine images at rest were acquired to improve the image quality. The examination was terminated if new or worsening wall-motion abnormalities or chest pain occurred or when > 85% of age-predicted maximum heart rate was reached. Myocardial ischemia was defined as new onset of wall-motion abnormality in at least one segment. In addition, late gadolinium enhancement (LGE was performed. Images were evaluated by two blinded readers. Diagnostic accuracy was determined with coronary

  6. Post-traumatic stress disorder and cardiovascular disease.

    Science.gov (United States)

    Edmondson, Donald; von Känel, Roland

    2017-04-01

    In this paper, a first in a Series of two, we look at the evidence for an association of post-traumatic stress disorder with incident cardiovascular disease risk and the mechanisms that might cause this association, as well as the prevalence of post-traumatic stress disorder due to cardiovascular disease events and its associated prognostic risk. We discuss research done after the publication of previous relevant systematic reviews, and survey currently funded research from the two most active funders in the field: the National Institutes of Health and the US Veterans Administration. We conclude that post-traumatic stress disorder is a risk factor for incident cardiovascular disease, and a common psychiatric consequence of cardiovascular disease events that might worsen the prognosis of the cardiovascular disease. There are many candidate mechanisms for the link between post-traumatic stress disorder and cardiovascular disease, and several ongoing studies could soon point to the most important behavioural and physiological mechanisms to target in early phase intervention development. Similarly, targets are emerging for individual and environmental interventions that might offset the risk of post-traumatic stress disorder after cardiovascular disease events. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Genetic influences on cardiovascular stress reactivity

    NARCIS (Netherlands)

    Wu, Ting; Snieder, Harold; de Geus, Eco

    Individual differences in the cardiovascular response to stress play a central role in the reactivity hypothesis linking frequent exposure to psychosocial stress to adverse outcomes in cardiovascular health. To assess the importance of genetic factors, a meta-analysis was performed on all published

  8. Cardiovascular magnetic resonance in congenital heart disease

    International Nuclear Information System (INIS)

    Cazacu, A.; Ciubotaru, A.

    2010-01-01

    The increasing prevalence of congenital heart disease can be attributed to major improvements in diagnosis and treatment. Cardiovascular magnetic resonance imaging plays an important role in the clinical management strategy of patients with congenital heart disease. The development of new cardiovascular magnetic resonance (CMR) techniques allows comprehensive assessment of complex cardiac anatomy and function and provides information about the long-term residual post-operative lesions and complications of surgery. It overcomes many of the limitations of echocardiography and cardiac catheterization. This review evaluates the role of cardiovascular magnetic resonance imaging modality in the management of subject with congenital heart disease (CHD). (authors)

  9. Cardiovascular magnetic resonance in adults with previous cardiovascular surgery.

    Science.gov (United States)

    von Knobelsdorff-Brenkenhoff, Florian; Trauzeddel, Ralf Felix; Schulz-Menger, Jeanette

    2014-03-01

    Cardiovascular magnetic resonance (CMR) is a versatile non-invasive imaging modality that serves a broad spectrum of indications in clinical cardiology and has proven evidence. Most of the numerous applications are appropriate in patients with previous cardiovascular surgery in the same manner as in non-surgical subjects. However, some specifics have to be considered. This review article is intended to provide information about the application of CMR in adults with previous cardiovascular surgery. In particular, the two main scenarios, i.e. following coronary artery bypass surgery and following heart valve surgery, are highlighted. Furthermore, several pictorial descriptions of other potential indications for CMR after cardiovascular surgery are given.

  10. Cardiovascular outcomes after pharmacologic stress myocardial perfusion imaging.

    Science.gov (United States)

    Lee, Douglas S; Husain, Mansoor; Wang, Xuesong; Austin, Peter C; Iwanochko, Robert M

    2016-04-01

    While pharmacologic stress single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is used for noninvasive evaluation of patients who are unable to perform treadmill exercise, its impact on net reclassification improvement (NRI) of prognosis is unknown. We evaluated the prognostic value of pharmacologic stress MPI for prediction of cardiovascular death or non-fatal myocardial infarction (MI) within 1 year at a single-center, university-based laboratory. We examined continuous and categorical NRI of pharmacologic SPECT-MPI for prediction of outcomes beyond clinical factors alone. Six thousand two hundred forty patients (median age 66 years [IQR 56-74], 3466 men) were studied and followed for 5963 person-years. SPECT-MPI variables associated with increased risk of cardiovascular death or non-fatal MI included summed stress score, stress ST-shift, and post-stress resting left ventricular ejection fraction ≤50%. Compared to a clinical model which included age, sex, cardiovascular disease, risk factors, and medications, model χ(2) (210.5 vs. 281.9, P statistic (0.74 vs. 0.78, P stress score, stress ST-shift and stress resting left ventricular ejection fraction). SPECT-MPI predictors increased continuous NRI by 49.4% (P 3% annualized risk of cardiovascular death or non-fatal MI, yielded a 15.0% improvement in NRI (95% CI 7.6%-27.6%, P stress MPI substantially improved net reclassification of cardiovascular death or MI risk beyond that afforded by clinical factors. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Sleep restriction undermines cardiovascular adaptation during stress, contingent on emotional stability.

    Science.gov (United States)

    Lü, Wei; Hughes, Brian M; Howard, Siobhán; James, Jack E

    2018-02-01

    Sleep loss is associated with increased cardiovascular disease, but physiological mechanisms accounting for this relationship are largely unknown. One possible mechanism is that sleep restriction exerts effects on cardiovascular stress responses, and that these effects vary between individuals. Emotional stability (ES) is a personality trait pertinent to sleep restriction and stress responding. However, no study to date has explored how ES and sleep-restriction interactively affect cardiovascular stress responses or processes of adaptation during stress. The present study sought to investigate the association between ES and impact of sleep restriction on cardiovascular function during stress, with particular regard to the trajectory of cardiovascular function change across time. Ninety female university students completed a laboratory vigilance stress task while undergoing continuous cardiovascular (SBP, DBP, HR, SV, CO, TPR) monitoring, after either a night of partial sleep restriction (40% of habitual sleep duration) or a full night's rest. Individuals high in ES showed stable and adaptive cardiovascular (SBP, SV, CO) responses throughout stress exposure, regardless of sleep. In contrast, individuals low in ES exhibited cardiovascular adaptation during stress exposure while rested, but disrupted adaption while sleep-restricted. These findings suggest that sleep-restriction undermines healthful cardiovascular adaptation to stress for individuals low in ES. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia.

    OpenAIRE

    Manka, R; Paetsch, I; Schnackenburg, B; Gebker, R; Fleck, E; Jahnke, C

    2010-01-01

    Abstract Background The purpose of this study was to determine the ability of Blood Oxygen Level Dependent (BOLD) cardiovascular magnetic resonance (CMR) to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD). Methods Forty-six patients (34 men; age 65 ± 9 years,) with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was perfor...

  13. Emotional Stress and Cardiovascular Complications in Animal Models: A Review of the Influence of Stress Type.

    Science.gov (United States)

    Crestani, Carlos C

    2016-01-01

    Emotional stress has been recognized as a modifiable risk factor for cardiovascular diseases. The impact of stress on physiological and psychological processes is determined by characteristics of the stress stimulus. For example, distinct responses are induced by acute vs. chronic aversive stimuli. Additionally, the magnitude of stress responses has been reported to be inversely related to the degree of predictability of the aversive stimulus. Therefore, the purpose of the present review was to discuss experimental research in animal models describing the influence of stressor stimulus characteristics, such as chronicity and predictability, in cardiovascular dysfunctions induced by emotional stress. Regarding chronicity, the importance of cardiovascular and autonomic adjustments during acute stress sessions and cardiovascular consequences of frequent stress response activation during repeated exposure to aversive threats (i.e., chronic stress) is discussed. Evidence of the cardiovascular and autonomic changes induced by chronic stressors involving daily exposure to the same stressor (predictable) vs. different stressors (unpredictable) is reviewed and discussed in terms of the impact of predictability in cardiovascular dysfunctions induced by stress.

  14. Extraversion and cardiovascular responses to recurrent social stress: Effect of stress intensity.

    Science.gov (United States)

    Lü, Wei; Xing, Wanying; Hughes, Brian M; Wang, Zhenhong

    2017-10-28

    The present study sought to establish whether the effects of extraversion on cardiovascular responses to recurrent social stress are contingent on stress intensity. A 2×5×1 mixed-factorial experiment was conducted, with social stress intensity as a between-subject variable, study phase as a within-subject variable, extraversion as a continuous independent variable, and cardiovascular parameter (HR, SBP, DBP, or RSA) as a dependent variable. Extraversion (NEO-FFI), subjective stress, and physiological stress were measured in 166 undergraduate students randomly assigned to undergo moderate (n=82) or high-intensity (n=84) social stress (a public speaking task with different levels of social evaluation). All participants underwent continuous physiological monitoring while facing two consecutive stress exposures distributed across five laboratory phases: baseline, stress exposure 1, post-stress 1, stress exposure 2, post-stress 2. Results indicated that under moderate-intensity social stress, participants higher on extraversion exhibited lesser HR reactivity to stress than participants lower on extraversion, while under high-intensity social stress, they exhibited greater HR, SBP, DBP and RSA reactivity. Under both moderate- and high-intensity social stress, participants higher on extraversion exhibited pronounced SBP and DBP response adaptation to repeated stress, and showed either better degree of HR recovery or greater amount of SBP and DBP recovery after stress. These findings suggest that individuals higher on extraversion exhibit physiological flexibility to cope with social challenges and benefit from adaptive cardiovascular responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Chronic stress impacts the cardiovascular system: animal models and clinical outcomes.

    Science.gov (United States)

    Golbidi, Saeid; Frisbee, Jefferson C; Laher, Ismail

    2015-06-15

    Psychological stresses are associated with cardiovascular diseases to the extent that cardiovascular diseases are among the most important group of psychosomatic diseases. The longstanding association between stress and cardiovascular disease exists despite a large ambiguity about the underlying mechanisms. An array of possibilities have been proposed including overactivity of the autonomic nervous system and humoral changes, which then converge on endothelial dysfunction that initiates unwanted cardiovascular consequences. We review some of the features of the two most important stress-activated systems, i.e., the humoral and nervous systems, and focus on alterations in endothelial function that could ensue as a result of these changes. Cardiac and hematologic consequences of stress are also addressed briefly. It is likely that activation of the inflammatory cascade in association with oxidative imbalance represents key pathophysiological components of stress-induced cardiovascular changes. We also review some of the commonly used animal models of stress and discuss the cardiovascular outcomes reported in these models of stress. The unique ability of animals for adaptation under stressful conditions lessens the extrapolation of laboratory findings to conditions of human stress. An animal model of unpredictable chronic stress, which applies various stress modules in a random fashion, might be a useful solution to this predicament. The use of stress markers as indicators of stress intensity is also discussed in various models of animal stress and in clinical studies. Copyright © 2015 the American Physiological Society.

  16. Openness to experience and adapting to change: Cardiovascular stress habituation to change in acute stress exposure.

    Science.gov (United States)

    Ó Súilleabháin, Páraic S; Howard, Siobhán; Hughes, Brian M

    2018-05-01

    Underlying psychophysiological mechanisms of effect linking openness to experience to health outcomes, and particularly cardiovascular well-being, are unknown. This study examined the role of openness in the context of cardiovascular responsivity to acute psychological stress. Continuous cardiovascular response data were collected for 74 healthy young female adults across an experimental protocol, including differing counterbalanced acute stressors. Openness was measured via self-report questionnaire. Analysis of covariance revealed openness was associated with systolic blood pressure (SBP; p = .016), and diastolic blood pressure (DBP; p = .036) responsivity across the protocol. Openness was also associated with heart rate (HR) responding to the initial stress exposure (p = .044). Examination of cardiovascular adaptation revealed that higher openness was associated with significant SBP (p = .001), DBP (p = .009), and HR (p = .002) habituation in response to the second differing acute stress exposure. Taken together, the findings suggest persons higher in openness are characterized by an adaptive cardiovascular stress response profile within the context of changing acute stress exposures. This study is also the first to demonstrate individual differences in cardiovascular adaptation across a protocol consisting of differing stress exposures. More broadly, this research also suggests that future research may benefit from conceptualizing an adaptive fitness of openness within the context of change. In summary, the present study provides evidence that higher openness stimulates short-term stress responsivity, while ensuring cardiovascular habituation to change in stress across time. © 2017 Society for Psychophysiological Research.

  17. Clinical applications of cardiovascular magnetic resonance imaging

    International Nuclear Information System (INIS)

    Marcu, C.B.; Beek, A.M.; Van Rossum, A.C.

    2006-01-01

    Cardiovascular magnetic resonance imaging (MRI) has evolved from an effective research tool into a clinically proven, safe and comprehensive imaging modality. It provides anatomic and functional information in acquired and congenital heart disease and is the most precise technique for quantification of ventricular volumes, function and mass. Owing to its excellent interstudy reproducibility, cardiovascular MRI is the optimal method for assessment of changes in ventricular parameters after therapeutic intervention. Delayed contrast enhancement is an accurate and robust method used in the diagnosis of ischemic and nonischemic cardiomyopathies and less common diseases, such as cardiac sarcoidosis and myocarditis. First-pass magnetic contrast myocardial perfusion is becoming an alternative to radionuclide techniques for the detection of coronary atherosclerotic disease. In this review we outline the techniques used in cardiovascular MRI and discuss the most common clinical applications. (author)

  18. Magnetic resonance imaging of the cardiovascular system

    International Nuclear Information System (INIS)

    Masuda, Yoshiaki; Imai, Hiroshi; Watanabe, Sigeru; Inagaki, Yoshiaki; Tateno, Yukio; Ikehira, Hiroo.

    1990-01-01

    Magnetic resonance imaging (MRI) is a new noninvasive technique for visualization of the cardiovascular system, and is used to evaluate tissue characteristics, cardiac function and blood flow abnormalities, as well as to obtain morphological information. In this paper we presented results of clinical and laboratory research obtained using conventional spin echo MRI with regard to cardiovascular anatomy, tissue characterization and physiology. Furthermore, experience with two new techniques, cine-MRI and volume-selected MR spectroscopy, and their potential clinical usefulness in detecting cardiovascular diseases are documented. (author)

  19. Safety and observer variability of cardiac magnetic resonance imaging combined with low-dose dobutamine stress-testing in patients with complex congenital heart disease

    NARCIS (Netherlands)

    Robbers-Visser, D.; Luijnenburg, S.E.; Berg, J. van den; Roos-Hesselink, J.W.; Strengers, J.L.; Kapusta, L.; Moelker, A.; Helbing, W.A.

    2011-01-01

    BACKGROUND: In patients with complex congenital heart disease (CHD) abnormal ventricular stress responses have been reported with dobutamine stress cardiovascular magnetic resonance (DCMR). These abnormal stress responses are potential indicators of long-term outcome. However, safety and

  20. Clinical advances in cardiovascular magnetic resonace imaging and angiography

    NARCIS (Netherlands)

    Bosch, van den H.C.M.

    2018-01-01

    Cardiovascular magnetic resonance imaging is an important noninvasive imaging modality for the diagnosis, clinical work‐up and treatment planning in patients suspected for a wide range of cardiovascular pathology. CMR imaging is accurate and reliable, and provides invaluable information to evaluate

  1. Stressing on the nucleolus in cardiovascular disease.

    Science.gov (United States)

    Hariharan, Nirmala; Sussman, Mark A

    2014-06-01

    The nucleolus is a multifunctional organelle with multiple roles involving cell proliferation, growth, survival, ribosome biogenesis and stress response signaling. Alteration of nucleolar morphology and architecture signifies an early response to increased cellular stress. This review briefly summarizes nucleolar response to cardiac stress signals and details the role played by nucleolar proteins in cardiovascular pathophysiology. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease. © 2013.

  2. Magnetic resonance imaging in cardiovascular disease

    International Nuclear Information System (INIS)

    Eckel, C.G.; Mettler, F.A. Jr.; Wicks, J.D.; Stevens, G.F.

    1986-01-01

    How does magnetic resonance imaging (MRI) currently contribute in the evaluation of patients with suspected heart disease? What role will MRI play in the future in evaluation of cardiovascular disease? To understand better where MRI fits into the diagnostic algorithm of cardiovascular disease the authors first consider the characteristics that they would like to see in the ideal diagnostic test and then survey the available cardiac diagnostic tests to note the characteristics that limit or recommend a test. In the final analysis, the justification for expensive diagnostic tests such as MRI must be an overall improvement in survival or quality of life in those patients treated after diagnosis

  3. Diabetic Cardiovascular Disease Induced by Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Yosuke Kayama

    2015-10-01

    Full Text Available Cardiovascular disease (CVD is the leading cause of morbidity and mortality among patients with diabetes mellitus (DM. DM can lead to multiple cardiovascular complications, including coronary artery disease (CAD, cardiac hypertrophy, and heart failure (HF. HF represents one of the most common causes of death in patients with DM and results from DM-induced CAD and diabetic cardiomyopathy. Oxidative stress is closely associated with the pathogenesis of DM and results from overproduction of reactive oxygen species (ROS. ROS overproduction is associated with hyperglycemia and metabolic disorders, such as impaired antioxidant function in conjunction with impaired antioxidant activity. Long-term exposure to oxidative stress in DM induces chronic inflammation and fibrosis in a range of tissues, leading to formation and progression of disease states in these tissues. Indeed, markers for oxidative stress are overexpressed in patients with DM, suggesting that increased ROS may be primarily responsible for the development of diabetic complications. Therefore, an understanding of the pathophysiological mechanisms mediated by oxidative stress is crucial to the prevention and treatment of diabetes-induced CVD. The current review focuses on the relationship between diabetes-induced CVD and oxidative stress, while highlighting the latest insights into this relationship from findings on diabetic heart and vascular disease.

  4. Accelerometer-determined physical activity and the cardiovascular response to mental stress in children.

    Science.gov (United States)

    Spartano, Nicole L; Heffernan, Kevin S; Dumas, Amy K; Gump, Brooks B

    2017-01-01

    Cardiovascular reactivity has been associated with future hypertension and cardiovascular mortality. Higher physical activity (PA) has been associated with lower cardiovascular reactivity in adults, but little data is available in children. The purpose of this study was to examine the relationship between PA and cardiovascular reactivity to mental stress in children. Cross-sectional study. This study sample included children from the Oswego Lead Study (n=79, 46% female, 9-11 years old). Impedance cardiography was performed while children participated in a stress response protocol. Children were also asked to wear Actigraph accelerometers on their wrists for 3 days to measure intensity and duration of PA and sedentary time. In multivariable models, moderate to vigorous (MV) PA was associated with lower body mass index (BMI) percentile and lower total peripheral resistance (TPR) response to stress (beta=-0.025, p=0.02; beta=-0.009, p=0.05). After additional adjustment for BMI, MVPA was also associated with lower diastolic blood pressure response to stress (beta=-0.01, p=0.03). Total PA and sedentary time were not associated with BMI or cardiovascular responses to stress. A modest, inverse relation of PA to vascular reactivity to mental stress was observed in children. These data provide confirmatory evidence that the promotion of PA recommendations for children are important for cardiovascular health. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  5. Social identity influences stress appraisals and cardiovascular reactions to acute stress exposure.

    Science.gov (United States)

    Gallagher, Stephen; Meaney, Sarah; Muldoon, Orla T

    2014-09-01

    This study tested a recent theoretical development in stress research to see whether group membership influenced cardiovascular reactions following exposure to acute stress. Participants (N = 104) were exposed to a message in which a maths test was described as stressful or challenging by an ingroup member (a student) or outgroup member (a stress disorder sufferer). Systolic blood pressure and diastolic blood pressure(DBP) and heart rate (HR) were monitored throughout a standard reactivity study. As expected, a significant interaction was found; relative to those who were told that the task was challenging, ingroup members reported more stress and had higher DBP and HR reactivity when told by an ingroup member that the maths task was stressful; task information did not have the same effect for outgroup members. These results indicate that informational support is not constant but varies as a function of group membership. Finally, this recent development in stress research may prove useful for those interested in investigating the interactions between social, psychological and physiological processes underlying health disparities. What is already known on this subject? Stress is a common risk factor for hypertension and coronary heart disease. Social support has been found to reduce cardiovascular reactions to acute psychological stress. The influence of social support on stress varies as a consequence of social identity. What does this study add? The social group that one belongs to influences how one appraises and responds to stress. Social identity provides a useful framework for understanding how social processes are associated with health disparities. © 2013 The British Psychological Society.

  6. Occupational stress and cardiovascular risk factors in high-ranking government officials and office workers.

    Science.gov (United States)

    Mirmohammadi, Seyyed Jalil; Taheri, Mahmoud; Mehrparvar, Amir Houshang; Heydari, Mohammad; Saadati Kanafi, Ali; Mostaghaci, Mehrdad

    2014-08-01

    Cardiovascular diseases are among the most important sources of mortality and morbidity, and have a high disease burden. There are some major well-known risk factors, which contribute to the development of these diseases. Occupational stress is caused due to imbalance between job demands and individual's ability, and it has been implicated as an etiology for cardiovascular diseases. This study was conducted to evaluate the cardiovascular risk factors and different dimensions of occupational stress in high-ranking government officials, comparing an age and sex-matched group of office workers with them. We invited 90 high-ranking officials who managed the main governmental offices in a city, and 90 age and sex-matched office workers. The subjects were required to fill the occupational role questionnaire (Osipow) which evaluated their personal and medical history as well as occupational stress. Then, we performed physical examination and laboratory tests to check for cardiovascular risk factors. Finally, the frequency of cardiovascular risk factors and occupational stress of two groups were compared. High-ranking officials in our study had less work experience in their current jobs and smoked fewer pack-years of cigarette, but they had higher waist and hip circumference, higher triglyceride level, more stress from role overload and responsibility, and higher total stress score. Our group of office workers had more occupational stress because of role ambiguity and insufficiency, but their overall job stress was less than officials. The officials have higher scores in some dimensions of occupational stress and higher overall stress score. Some cardiovascular risk factors were also more frequent in managers.

  7. Biological markers of oxidative stress: Applications to cardiovascular research and practice

    Directory of Open Access Journals (Sweden)

    Edwin Ho

    2013-01-01

    Full Text Available Oxidative stress is a common mediator in pathogenicity of established cardiovascular risk factors. Furthermore, it likely mediates effects of emerging, less well-defined variables that contribute to residual risk not explained by traditional factors. Functional oxidative modifications of cellular proteins, both reversible and irreversible, are a causal step in cellular dysfunction. Identifying markers of oxidative stress has been the focus of many researchers as they have the potential to act as an “integrator” of a multitude of processes that drive cardiovascular pathobiology. One of the major challenges is the accurate quantification of reactive oxygen species with very short half-life. Redox-sensitive proteins with important cellular functions are confined to signalling microdomains in cardiovascular cells and are not readily available for quantification. A popular approach is the measurement of stable by-products modified under conditions of oxidative stress that have entered the circulation. However, these may not accurately reflect redox stress at the cell/tissue level. Many of these modifications are “functionally silent”. Functional significance of the oxidative modifications enhances their validity as a proposed biological marker of cardiovascular disease, and is the strength of the redox cysteine modifications such as glutathionylation. We review selected biomarkers of oxidative stress that show promise in cardiovascular medicine, as well as new methodologies for high-throughput measurement in research and clinical settings. Although associated with disease severity, further studies are required to examine the utility of the most promising oxidative biomarkers to predict prognosis or response to treatment.

  8. Occupational status and job stress in relation to cardiovascular stress reactivity in Japanese workers.

    Science.gov (United States)

    Hirokawa, Kumi; Ohira, Tetsuya; Nagayoshi, Mako; Kajiura, Mitsugu; Imano, Hironori; Kitamura, Akihiko; Kiyama, Masahiko; Okada, Takeo; Iso, Hiroyasu

    2016-12-01

    This study aimed to investigate the effects of occupational status and job stress factors on cardiovascular stress reactivity in Japanese workers. In this baseline assessment between 2001 and 2009 in Osaka, Japan, we examined 928 healthy Japanese employees (330 men, 598 women) from two occupational statuses: managers/professionals and general workers. A brief job stress questionnaire was used to evaluate job stress levels. Systolic and diastolic blood pressure (SBP, DBP), heart rate, heart rate variability (high-frequency [HF], low-frequency [LF], LF/HF], and peripheral blood flow were measured at rest and during two stressful tasks. Changes in stress reactivity were calculated as the difference between the measured variables during the tasks and the rest period. Men showed inverse associations between quantitative job overload and DBP, heart rate, and LF/HF, between physical demands and blood pressure (SBP, DBP), and between a poor physical environment and HF. Men also had positive associations between qualitative job overload and heart rate, and between physical demands and peripheral blood flow (all p occupational status, significant associations between job stress and changes in stress reactivity were observed in male managers/professionals and female general workers (p stress levels are associated with changes in cardiovascular stress reactivity in men and women. Occupational status may modify these associations.

  9. Impact of chronic kidney disease and stress myocardial perfusion imaging as a predictor of cardiovascular events

    International Nuclear Information System (INIS)

    Furuhashi, Tatsuhiko; Joki, Nobuhiko; Hase, Hiroki; Masai, Hirofumi; Kunimasa, Taeko; Nakazato, Ryo; Fukuda, Hiroshi; Sugi, Kaoru; Moroi, Masao

    2011-01-01

    Stress myocardial perfusion imaging (MPI) is an established means of predicting cardiovascular events and is suitable in chronic kidney disease (CKD) patients. We aimed to evaluate the prognostic value of CKD parameters and an abnormal stress MPI for cardiovascular events. A total of 495 patients with suspected coronary artery disease (CAD) or history of CAD including 130 CKD patients not undergoing hemodialysis, underwent stress MPI (313 males, mean age 70 years) and were followed up for 14 months (mean period). CKD was defined as an estimated GFR of 2 and/or persistent proteinuria. Cardiovascular events were defined as sudden cardiac death, acute coronary syndrome and congestive heart failure requiring hospitalization. Cardiovascular events occurred in 41 (8.3%) patients. Multivariate Cox regression analysis indicated that CKD [hazard ratio (HR) =3.76, p<0.001] and a stress MPI summed difference score (SDS) of ≥2 (HR=3.78, p<0.001) were independent predictors of cardiovascular events; CKD plus abnormal stress MPI was also a strong predictor of cardiovascular events (non-CKD and SDS <2 vs. CKD and SDS ≥2, HR=15.9, p<0.001). Both CKD and myocardial ischemia detected by stress MPI are independent predictors for cardiovascular events. Coexistence of CKD and myocardial ischemia detected by stress MPI is more useful for short-term risk stratification of cardiovascular events. (author)

  10. Cardiovascular Reactivity in Patients With Major Depressive Disorder With High- or Low-Level Depressive Symptoms: A Cross-Sectional Comparison of Cardiovascular Reactivity to Laboratory-Induced Mental Stress.

    Science.gov (United States)

    Wang, Mei-Yeh; Chiu, Chen-Huan; Lee, Hsin-Chien; Su, Chien-Tien; Tsai, Pei-Shan

    2016-03-01

    Depression increases the risk of adverse cardiac events. Cardiovascular reactivity is defined as the pattern of cardiovascular responses to mental stress. An altered pattern of cardiovascular reactivity is an indicator of subsequent cardiovascular disease. Because depression and adverse cardiac events may have a dose-dependent association, this study examined the differences in cardiovascular reactivity to mental stress between patients with major depressive disorder (MDD) with high depression levels and those with low depression levels. Moreover, autonomic nervous system regulation is a highly plausible biological mechanism for the pattern of cardiovascular reactivity to mental stress. The association between cardiovascular reactivity and parameters of heart rate variability (HRV), an index for quantifying autonomic nervous system activity modulation, was thus examined. This study included 88 patients with MDD. HRV was measured before stress induction. The Stroop Color and Word Test and mirror star-tracing task were used to induce mental stress. We observed no significant association between depressive symptom level and any of the cardiovascular reactivity parameters. Cardiovascular reactivity to mental stress was comparable between patients with MDD with high-level depressive symptoms and those with low-level depressive symptoms. After adjusting for confounding variables, the high-frequency domain of HRV was found to be an independent predictor of the magnitude of heart rate reactivity (β = -.33, p = .002). In conclusion, the magnitude of cardiovascular reactivity may be independent of depression severity in patients with MDD. The autonomic regulation of cardiovascular responses to mental stress primarily influences heart rate reactivity in patients with MDD. © The Author(s) 2015.

  11. Studies on laws of stress-magnetization based on magnetic memory testing technique

    Science.gov (United States)

    Ren, Shangkun; Ren, Xianzhi

    2018-03-01

    Metal magnetic memory (MMM) testing technique is a novel testing method which can early test stress concentration status of ferromagnetic components. Under the different maximum tensile stress, the relationship between the leakage magnetic field of at certain point of cold rolled steel specimen and the tensile stress was measured during the process of loading and unloading by repeated. It shows that when the maximum tensile stress is less than 610 MPa, the relationship between the magnetic induction intensity and the stress is linear; When the maximum tensile stress increase from 610 MPa to 653 MPa of yield point, the relationship between the magnetic induction intensity and the tensile becomes bending line. The location of the extreme point of the bending line will move rapidly from the position of smaller stress to the larger stress position, and the variation of magnetic induction intensity increases rapidly. When the maximum tensile stress is greater than the 653 MPa of yield point, the variation of the magnetic induction intensity remains large, and the position of the extreme point moves very little. In theoretical aspects, tensile stress is to be divided into ordered stress and disordered stress. In the stage of elastic stress, a microscopic model of the order stress magnetization is established, and the conclusions are in good agreement with the experimental data. In the plastic deformation stage, a microscopic model of disordered stress magnetization is established, and the conclusions are in good agreement with the experimental data, too. The research results can provide reference for the accurate quantitative detection and evaluation of metal magnetic memory testing technology.

  12. Cardiovascular response to acute stress in freely moving rats: time-frequency analysis.

    Science.gov (United States)

    Loncar-Turukalo, Tatjana; Bajic, Dragana; Japundzic-Zigon, Nina

    2008-01-01

    Spectral analysis of cardiovascular series is an important tool for assessing the features of the autonomic control of the cardiovascular system. In this experiment Wistar rats ecquiped with intraarterial catheter for blood pressure (BP) recording were exposed to stress induced by blowing air. The problem of non stationary data was overcomed applying the Smoothed Pseudo Wigner Villle (SPWV) time-frequency distribution. Spectral analysis was done before stress, during stress, immediately after stress and later in recovery. The spectral indices were calculated for both systolic blood pressure (SBP) and pulse interval (PI) series. The time evolution of spectral indices showed perturbed sympathovagal balance.

  13. Stress, behavior, and biology: Risk factors for cardiovascular diseases in youth

    Science.gov (United States)

    Psychological stress is associated with cardiovascular disease (CVD) pathogenesis during childhood. Stress promotes atherogenic behaviors in children including snacking of energy dense foods and reduced physical activity; and it also increases adiposity. Stress-induced CV reactivity may also be athe...

  14. Implication of Oxidative Stress in Fetal Programming of Cardiovascular Disease

    Science.gov (United States)

    Rodríguez-Rodríguez, Pilar; Ramiro-Cortijo, David; Reyes-Hernández, Cynthia G.; López de Pablo, Angel L.; González, M. Carmen; Arribas, Silvia M.

    2018-01-01

    Lifestyle and genetic background are well known risk factors of cardiovascular disease (CVD). A third contributing factor is suboptimal fetal development, due to nutrient or oxygen deprivation, placental insufficiency, or exposure to toxic substances. The fetus adapts to adverse intrauterine conditions to ensure survival; the immediate consequence is low birth weight (LBW) and the long-term effect is an increased susceptibility to develop CVD in adult life. This process is known as Developmental Origins of Health and Disease (DOHaD) or fetal programming of CVD. The influence of fetal life for the future cardiovascular health of the individual has been evidenced by numerous epidemiologic studies in populations suffering from starvation during intrauterine life. Furthermore, experimental animal models have provided support and enabled exploring the underlying mechanisms. Oxidative stress seems to play a central role in fetal programming of CVD, both in the response of the feto-placental unit to the suboptimal intrauterine environment and in the alterations of physiologic systems of cardiovascular control, ultimately leading to disease. This review aims to summarize current knowledge on the alterations in oxidative balance in response to fetal stress factors covering two aspects. Firstly, the evidence from human studies of the implication of oxidative stress in LBW induced by suboptimal conditions during intrauterine life, emphasizing the role of the placenta. In the second part we summarize data on specific redox alterations in key cardiovascular control organs induced by exposure to known stress factors in experimental animals and discuss the emerging role of the mitochondria. PMID:29875698

  15. Evaluating personality as a moderator of the association between life events stress and cardiovascular reactivity to acute stress.

    Science.gov (United States)

    Gallagher, Stephen; O'Riordan, Adam; McMahon, Grace; Creaven, Ann-Marie

    2018-04-01

    The present study investigated the possible interaction between life events stress and personality in predicting cardiovascular stress responses. Participants (N = 184) completed psychometric measures of life event stress and personality styles and had cardiovascular responses monitored during a standardised stress testing protocol. In adjusted models, the observed blunted association between life event stress and SBP and DBP was moderated by openness; this was more evident at -1SD below the mean openness value. Further, the association between life event stress and TPR vascular resistance was found to be moderated by conscientiousness. In particular, we found conscientiousness at both the mean and 1SD above the mean buffered against the negative impact of life stress on TPR reactivity. The findings are discussed in relation to theory and future directions. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Cardiovascular Complications of Sleep Apnea: Role of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Mohammad Badran

    2014-01-01

    Full Text Available Obstructive sleep apnea (OSA occurs in 2% of middle-aged women and 4% of middle-aged men with a higher prevalence among obese subjects. This condition is considered as an independent risk factor for cerebrovascular and cardiovascular diseases. One of the major pathophysiological characteristics of OSA is intermittent hypoxia. Hypoxia can lead to oxidative stress and overproduction of reactive oxygen species, which can lead to endothelial dysfunction, a hallmark of atherosclerosis. Many animal models, such as the rodent model of intermittent hypoxia, mimic obstructive sleep apnea in human patients and allow more in-depth investigation of biological and cellular mechanisms of this condition. This review discusses the role of oxidative stress in cardiovascular disease resulting from OSA in humans and animal models.

  17. Diagnostic performance of dual-energy CT stress myocardial perfusion imaging: direct comparison with cardiovascular MRI.

    Science.gov (United States)

    Ko, Sung Min; Song, Meong Gun; Chee, Hyun Kun; Hwang, Hweung Kon; Feuchtner, Gudrun Maria; Min, James K

    2014-12-01

    The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease. One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemo-dynamically significant stenosis was assessed before and after stress perfusion DECT on a per-vessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard. The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p=0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone. Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically significant coronary stenosis.

  18. Occupational status and job stress in relation to cardiovascular stress reactivity in Japanese workers

    Directory of Open Access Journals (Sweden)

    Kumi Hirokawa

    2016-12-01

    Full Text Available This study aimed to investigate the effects of occupational status and job stress factors on cardiovascular stress reactivity in Japanese workers. In this baseline assessment between 2001 and 2009 in Osaka, Japan, we examined 928 healthy Japanese employees (330 men, 598 women from two occupational statuses: managers/professionals and general workers. A brief job stress questionnaire was used to evaluate job stress levels. Systolic and diastolic blood pressure (SBP, DBP, heart rate, heart rate variability (high-frequency [HF], low-frequency [LF], LF/HF], and peripheral blood flow were measured at rest and during two stressful tasks. Changes in stress reactivity were calculated as the difference between the measured variables during the tasks and the rest period. Men showed inverse associations between quantitative job overload and DBP, heart rate, and LF/HF, between physical demands and blood pressure (SBP, DBP, and between a poor physical environment and HF. Men also had positive associations between qualitative job overload and heart rate, and between physical demands and peripheral blood flow (all p < 0.05. Women showed inverse associations between qualitative job overload and SBP, and showed positive associations between qualitative job overload and peripheral blood flow, and between a poor physical environment and SBP (all p < 0.05. When stratified by occupational status, significant associations between job stress and changes in stress reactivity were observed in male managers/professionals and female general workers (p < 0.05. Job stress levels are associated with changes in cardiovascular stress reactivity in men and women. Occupational status may modify these associations.

  19. Stress perfusion magnetic resonance imaging to detect coronary artery lesions in children.

    Science.gov (United States)

    Vijarnsorn, Chodchanok; Noga, Michelle; Schantz, Daryl; Pepelassis, Dion; Tham, Edythe B

    2017-05-01

    Stress perfusion cardiovascular magnetic resonance (CMR) is used widely in adult ischemic heart disease, but data in children is limited. We sought to evaluate feasibility, accuracy and prognostic value of stress CMR in children with suspected coronary artery disease (CAD). Stress CMR was reviewed from two pediatric centers over 5 years using a standard pharmacologic protocol. Wall motion abnormalities, perfusion deficits and late enhancement were correlated with coronary angiogram (CAG) when available, and clinical status at 1 year follow-up for major adverse cardiovascular events (MACE; coronary revascularization, non-fatal myocardial infarction and death due to CAD) was recorded. Sixty-four stress perfusion CMR studies in 48 children (10.9 ± 4.8 years) using adenosine; 59 (92%) and dipyridamole; 5 (8%), were reviewed. Indications were Kawasaki disease (39%), post arterial switch operation (12.5%), post heart transplantation (12.5%), post anomalous coronary artery repair (11%), chest pain (11%), suspected myocarditis or CAD (3%), post coronary revascularization (3%), and others (8%). Twenty-six studies were performed under sedation. Of all studies performed, 66% showed no evidence of ischemia or infarction, 28% had perfusion deficits and 6% had late gadolinium enhancement (LGE) without perfusion deficit. Compared to CAG, the positive predictive value (PPV) of stress CMR was 80% with negative predictive value (NPV) of 88%. At 1 year clinical follow-up, the PPV and NPV of stress CMR to predict MACE were 78 and 98%. Stress-perfusion CMR, in combination with LGE and wall motion-analysis is a feasible and an accurate method of diagnosing CAD in children. In difficult cases, it also helps guide clinical intervention by complementing conventional CAG with functional information.

  20. Technical competence in cardiovascular magnetic resonance and computed tomography

    International Nuclear Information System (INIS)

    Fernandes, Juliano Lara; Shiozaki, Afonso Akio; Azevedo Filho, Clerio Francisco de; Rochitte, Carlos Eduardo; Pinto, Ibraim Marciarelli Francisco; Lopes, Marly Maria Uellendahl; Schvartzman, Paulo Roberto

    2009-01-01

    Cardiovascular magnetic resonance and computed tomography have evolved as very practical and useful techniques applied in clinical cardiology. Due to their rapid acceptance in the cardiology community and widespread use, training of both cardiologists and radiologists on this subspecialty has not been homogeneous so far. This in part explains significant differences observed in the diverse background found in today’s practicing physicians who execute these exams. In order to guide training facilities as well as both payers, contractors and general cardiologists ordering the exam, this document provides a minimum standard that should be accomplished by all physicians who pursue education in the field and for those who already practice in it. The clinical competences listed in this statement are by no means thorough but should be required by all those involved in cardiovascular magnetic resonance and computed tomography as the customary requirements for current and future practitioners. (author)

  1. Sex differences in cardiovascular and subjective stress reactions: prospective evidence in a realistic military setting.

    Science.gov (United States)

    Taylor, Marcus K; Larson, Gerald E; Hiller Lauby, Melissa D; Padilla, Genieleah A; Wilson, Ingrid E; Schmied, Emily A; Highfill-McRoy, Robyn M; Morgan, Charles A

    2014-01-01

    Evidence points to heightened physiological arousal in response to acute stress exposure as both a prospective indicator and a core characteristic of posttraumatic stress disorder (PTSD). Because females may be at higher risk for PTSD development, it is important to evaluate sex differences in acute stress reactions. This study characterized sex differences in cardiovascular and subjective stress reactions among military survival trainees. One hundred and eighty-five military members (78% males) were studied before, during, and 24 h after stressful mock captivity. Cardiovascular (heart rate [HR], systolic blood pressure [SBP], diastolic blood pressure [DBP]) and dissociative states were measured at all three time points. Psychological impact of mock captivity was assessed during recovery. General linear modeling with repeated measures evaluated sex differences for each cardiovascular endpoint, and causal steps modeling was used to explore interrelationships among sex, cardiovascular reactions and psychological impact of mock captivity. Although females had lower SBP than males at all three time points, the difference was most pronounced at baseline and during stress. Accordingly, females showed greater residual elevation in SBP during recovery. Females had lower DBP at all three time points. In addition, females reported greater psychological impact of mock captivity than males. Exploratory causal steps modeling suggested that stress-induced HR may partially mediate the effect of sex on psychological impact of mock captivity. In conclusion, this study demonstrated sex-specific cardiovascular stress reactions in military personnel, along with greater psychological impact of stress exposure in females. This research may elucidate sex differences in PTSD development.

  2. Review of Journal of Cardiovascular Magnetic Resonance 2009

    Directory of Open Access Journals (Sweden)

    Neubauer S

    2010-03-01

    Full Text Available Abstract There were 56 articles published in the Journal of Cardiovascular Magnetic Resonance in 2009. The editors were impressed with the high quality of the submissions, of which our acceptance rate was about 40%. In accordance with open-access publishing, the articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. We have therefore chosen to briefly summarise the papers in this article for quick reference for our readers in broad areas of interest, which we feel will be useful to practitioners of cardiovascular magnetic resonance (CMR. In some cases where it is considered useful, the articles are also put into the wider context with a short narrative and recent CMR references. It has been a privilege to serve as the Editor of the JCMR this past year. I hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.

  3. BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia

    Directory of Open Access Journals (Sweden)

    Gebker Rolf

    2010-09-01

    Full Text Available Abstract Background The purpose of this study was to determine the ability of Blood Oxygen Level Dependent (BOLD cardiovascular magnetic resonance (CMR to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD. Methods Forty-six patients (34 men; age 65 ± 9 years, with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was performed in 3 short axis slices of the heart at rest and during adenosine stress (140 μg/kg/min followed by late gadolinium enhancement (LGE imaging. In all 16 standard myocardial segments, T2* values were derived at rest and under adenosine stress. Quantitative coronary angiography served as the standard of reference and defined normal myocardial segments (i.e. all 16 segments in patients without any CAD, ischemic segments (i.e. supplied by a coronary artery with ≥50% luminal narrowing and non-ischemic segments (i.e. supplied by a non-significantly stenosed coronary artery in patients with significant CAD. Results Coronary angiography demonstrated significant CAD in 23 patients. BOLD CMR at rest revealed significantly lower T2* values for ischemic segments (26.7 ± 11.6 ms compared to normal (31.9 ± 11.9 ms; p Conclusions Rest and stress BOLD CMR at 3Tesla proved feasible and differentiated between ischemic, non-ischemic, and normal myocardial segments in a clinical patient population. BOLD CMR during vasodilator stress identified patients with significant CAD.

  4. The histological basis of late gadolinium enhancement cardiovascular magnetic resonance in a patient with Anderson-Fabry disease.

    Science.gov (United States)

    Moon, James C; Sheppard, Mary; Reed, Emma; Lee, Phillip; Elliott, Perry M; Pennell, Dudley J

    2006-01-01

    Anderson-Fabry Disease (AFD) is a storage disease that mimics hypertrophic cardiomyopathy. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance occurs in approximately 50% of patients in the basal inferolateral LV wall, but how an intracellular storage disease causes focal LGE is unknown. We present a whole-heart histological validation that LGE is caused by focal myocardial collagen scarring. This scarring may be the substrate for electrical re-entry and sudden arrhythmic death. The reasons for this distribution of fibrosis are unclear, but may reflect inhomogeneous left ventricular wall stress.

  5. BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia.

    Science.gov (United States)

    Manka, Robert; Paetsch, Ingo; Schnackenburg, Bernhard; Gebker, Rolf; Fleck, Eckart; Jahnke, Cosima

    2010-09-22

    The purpose of this study was to determine the ability of blood oxygen level dependent (BOLD) cardiovascular magnetic resonance (CMR) to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD). Forty-six patients (34 men; age 65 ± 9 years,) with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was performed in 3 short axis slices of the heart at rest and during adenosine stress (140 μg/kg/min) followed by late gadolinium enhancement (LGE) imaging. In all 16 standard myocardial segments, T2* values were derived at rest and under adenosine stress. Quantitative coronary angiography served as the standard of reference and defined normal myocardial segments (i.e. all 16 segments in patients without any CAD), ischemic segments (i.e. supplied by a coronary artery with ≥50% luminal narrowing) and non-ischemic segments (i.e. supplied by a non-significantly stenosed coronary artery in patients with significant CAD). Coronary angiography demonstrated significant CAD in 23 patients. BOLD CMR at rest revealed significantly lower T2* values for ischemic segments (26.7 ± 11.6 ms) compared to normal (31.9 ± 11.9 ms; p BOLD CMR at 3Tesla proved feasible and differentiated between ischemic, non-ischemic, and normal myocardial segments in a clinical patient population. BOLD CMR during vasodilator stress identified patients with significant CAD.

  6. Prognostic utility of novel biomarkers of cardiovascular stress: the Framingham Heart Study.

    Science.gov (United States)

    Wang, Thomas J; Wollert, Kai C; Larson, Martin G; Coglianese, Erin; McCabe, Elizabeth L; Cheng, Susan; Ho, Jennifer E; Fradley, Michael G; Ghorbani, Anahita; Xanthakis, Vanessa; Kempf, Tibor; Benjamin, Emelia J; Levy, Daniel; Vasan, Ramachandran S; Januzzi, James L

    2012-09-25

    Biomarkers for predicting cardiovascular events in community-based populations have not consistently added information to standard risk factors. A limitation of many previously studied biomarkers is their lack of cardiovascular specificity. To determine the prognostic value of 3 novel biomarkers induced by cardiovascular stress, we measured soluble ST2, growth differentiation factor-15, and high-sensitivity troponin I in 3428 participants (mean age, 59 years; 53% women) in the Framingham Heart Study. We performed multivariable-adjusted proportional hazards models to assess the individual and combined ability of the biomarkers to predict adverse outcomes. We also constructed a "multimarker" score composed of the 3 biomarkers in addition to B-type natriuretic peptide and high-sensitivity C-reactive protein. During a mean follow-up of 11.3 years, there were 488 deaths, 336 major cardiovascular events, 162 heart failure events, and 142 coronary events. In multivariable-adjusted models, the 3 new biomarkers were associated with each end point (Pstatistic (P=0.005 or lower) and net reclassification improvement (P=0.001 or lower). Multiple biomarkers of cardiovascular stress are detectable in ambulatory individuals and add prognostic value to standard risk factors for predicting death, overall cardiovascular events, and heart failure.

  7. ECG gated magnetic resonance imaging in cardiovascular disease

    International Nuclear Information System (INIS)

    Park, Jae Hyung; Im, Chung Kie; Han, Man Chung; Kim, Chu Wan

    1985-01-01

    Using KAIS 0.15 Tesla resistive magnetic imaging system, ECG gated magnetic resonance (MR) image of various cardiovascular disease was obtained in 10 patients. The findings of MR image of the cardiovascular disease were analysed and the results were as follows: 1. In 6 cases of acquired and congenital cardiac diseases, there were 2 cases of myocardial infarction, 1 case of mitral stenosis and 3 cases of corrected transportation of great vessels. The others were 3 cases of aortic disease and 1 case of pericardial effusion with lymphoma. 2. Myocardial thinning and left ventricular aneurysm were detected in MR images of myocardial infarction. The left atrium was well delineated and enlarged in the case of mitral stenosis. And segmental analysis was possible in the cases of corrected transposition since all cardiac structures were well delineated anatomically. 3. In aortic diseases, the findings of MR image were enlarged lumen, compressed cardiac chambers in ascending aortic aneurysm, intimal flap, enhanced false lumen in dissecting aneurysm and irregular narrowing of aorta with arterial obstruction in Takayasu's arteritis. 4. Pericardial effusion revealed a conspicuous contrast with neighboring mediastinal fat and cardiac wall due to it low signal encircling cardiac wall. 5. ECG gated MR image is an accurate non-invasive imaging modality for the diagnosis of cardiovascular disease and better results of its clinical application are expected in the future with further development in the imaging system and more clinical experiences

  8. Technical competence in cardiovascular magnetic resonance and computed tomography; Competencia tecnica em ressonancia e tomografia cardiovascular

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Juliano Lara; Shiozaki, Afonso Akio; Azevedo Filho, Clerio Francisco de; Rochitte, Carlos Eduardo; Pinto, Ibraim Marciarelli Francisco; Lopes, Marly Maria Uellendahl; Schvartzman, Paulo Roberto, E-mail: jlaraf@fcm.unicamp.br [Universidade de Campinas (UNICAMP/GERT) SP (Brazil). Grupo de Estudo em Ressonancia e Tomografia Cardiovascular

    2009-10-15

    Cardiovascular magnetic resonance and computed tomography have evolved as very practical and useful techniques applied in clinical cardiology. Due to their rapid acceptance in the cardiology community and widespread use, training of both cardiologists and radiologists on this subspecialty has not been homogeneous so far. This in part explains significant differences observed in the diverse background found in today’s practicing physicians who execute these exams. In order to guide training facilities as well as both payers, contractors and general cardiologists ordering the exam, this document provides a minimum standard that should be accomplished by all physicians who pursue education in the field and for those who already practice in it. The clinical competences listed in this statement are by no means thorough but should be required by all those involved in cardiovascular magnetic resonance and computed tomography as the customary requirements for current and future practitioners. (author)

  9. Cardiovascular risk and stress in employees of a higher education institution

    Directory of Open Access Journals (Sweden)

    Eugênio Barbosa de Melo Júnior

    2016-01-01

    Full Text Available Objective: to analyze the association between high levels of stress and the frequency of cardiovascular risk factors in employees of a higher education institution. Methods: this is a cross-sectional study with 201 employees of a university. A form containing socioeconomic data, the International Physical Activity Questionnaire (short version, the Alcohol Use Disorders Identification Test and the Work Stress Scale were used for data collection. Data analysis was performed using the probability ratio and One-way analysis of variance tests. Results: worrisome frequencies of cardiovascular risk factors were identified, in which sedentary lifestyle, excess weight, and increased abdominal circumference presented the most expressive indexes. Regarding the stressors evaluated, some of the employees had increased stress indexes, distributed between the medium and high levels. Conclusion: sedentary lifestyle, excess weight, and increased abdominal circumference presented expressive high indexes, without statistically significant associations with the level of stress.

  10. Job stress and cardiovascular risk factors in male workers.

    Science.gov (United States)

    Kang, Myung Gun; Koh, Sang Baek; Cha, Bong Suk; Park, Jong Ku; Baik, Soon Koo; Chang, Sei Jin

    2005-05-01

    This study examined whether job stress (work demand and decision latitude) is associated with smoking, blood pressure, lipid level (total cholesterol, triglyceride, HDL cholesterol), and homocystein as risk factors for cardiovascular disease in Korean male workers. Study subjects of this study were recruited from a sample of 1,071 workers in 20 companies of W city and H counties, and they were grouped into four categories (high strain group, active group, passive group, and low strain group) based on the postulation of Karasek's Job Strain Model. Of them, we invited 160 male workers (40 people each subgroup) using a stratified sampling, and finally, 152 eligible participants were analyzed. In multivariate analyses, we found that decision latitude was associated with cholesterol, triglyceride, and homocystein and that work demand was related to smoking and systolic blood pressure. Job strain (the combination of high work demand with low decision latitude) was significantly related to higher levels of homocystein after controlling for age, BMI, smoking, and social support at workplace. These results indicate that job stress is associated with cardiovascular risk factors and might contribute to the development of cardiovascular disease. Some considerations for the future research were discussed.

  11. Cardiovascular reactivity to acute psychological stress following sleep deprivation.

    Science.gov (United States)

    Franzen, Peter L; Gianaros, Peter J; Marsland, Anna L; Hall, Martica H; Siegle, Greg J; Dahl, Ronald E; Buysse, Daniel J

    2011-10-01

    Psychological stress and sleep disturbances are highly prevalent and are both implicated in the etiology of cardiovascular diseases. Given the common co-occurrence of psychological distress and sleep disturbances including short sleep duration, this study examined the combined effects of these two factors on blood pressure reactivity to immediate mental challenge tasks after well-rested and sleep-deprived experimental conditions. Participants (n = 20) were healthy young adults free from current or past sleep, psychiatric, or major medical disorders. Using a within-subjects crossover design, we examined acute stress reactivity under two experimental conditions: after a night of normal sleep in the laboratory and after a night of total sleep deprivation. Two standardized psychological stress tasks were administered, a Stroop color-word naming interference task and a speech task, which were preceded by a prestress baseline period and followed by a poststress recovery period. Each period was 10 minutes in duration, and blood pressure recordings were collected every 2.5 minutes throughout each period. Mean blood pressure responses during stress and recovery periods were examined with a mixed-effects analysis of covariance, controlling for baseline blood pressure. There was a significant interaction between sleep deprivation and stress on systolic blood pressure (F(2,82.7) = 4.05, p = .02). Systolic blood pressure was higher in the sleep deprivation condition compared with the normal sleep condition during the speech task and during the two baseline periods. Sleep deprivation amplified systolic blood pressure increases to psychological stress. Sleep loss may increase cardiovascular risk by dysregulating stress physiology.

  12. Magnetic stresses in ideal MHD plasmas

    DEFF Research Database (Denmark)

    Jensen, V.O.

    1995-01-01

    The concept of magnetic stresses in ideal MHD plasma theory is reviewed and revisited with the aim of demonstrating its advantages as a basis for calculating and understanding plasma equilibria. Expressions are derived for the various stresses that transmit forces in a magnetized plasma...... and it is shown that the resulting magnetic forces on a finite volume element can be obtained by integrating the magnetic stresses over the surface of the element. The concept is used to rederive and discuss the equilibrium conditions for axisymmetric toroidal plasmas, including the virial theorem...... and the Shafranov shift. The method had pedagogical merits as it simplifies the calculations, improves the physical understanding and facilitates an assessment of the approximations made in the calculations....

  13. Relationship between occupational stress and cardiovascular diseases risk factors in drivers.

    Science.gov (United States)

    Biglari, Hamed; Ebrahimi, Mohammad Hossein; Salehi, Maryam; Poursadeghiyan, Mohsen; Ahmadnezhad, Iman; Abbasi, Milad

    2016-11-18

    Of all work stressors, occupational stress is the leading cause of many disorders among workers. Drivers are classified as a high risk group for work related stress. This study set out to determine the relationship between risk factors of cardiovascular diseases and occupational stress among drivers. Two hundred and twenty two Ilam's intercity drivers were selected for the study. For measuring work stress, the Osipow work stress questionnaire was used. After a 10-h fasting period, systolic and diastolic blood pressure was recorded. Intravenous blood samples were taken to determine cholesterol, triglyceride and blood glucose levels. The independent samples t-test and Pearson's correlation test were used to assess the relationship between variables and occupational stress. Seventy-one percent of the intercity drivers suffered from average to acute stress, and 3.1% of them suffered from acute stress. There was no significant relationship between occupational stress and diastolic blood pressure (p = 0.254) among the drivers. Nevertheless, the Pearson's correlation test demonstrated a strong relationship between work stress and blood glucose (p stress were observed in the Ilam's intercity drivers. Occupational stress may have effect on blood glucose levels but the results did not suggest a considerable relationship between risk factors of cardiovascular diseases and occupational stress among intercity drivers. Int J Occup Med Environ Health 2016;29(6):895-901. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  14. Physical versus psychological social stress in male rats reveals distinct cardiovascular, inflammatory and behavioral consequences

    Science.gov (United States)

    Padi, Akhila R.; Moffitt, Casey M.; Wilson, L. Britt; Wood, Christopher S.; Wood, Susan K.

    2017-01-01

    Repeated exposure to social stress can precipitate the development of psychosocial disorders including depression and comorbid cardiovascular disease. While a major component of social stress often encompasses physical interactions, purely psychological stressors (i.e. witnessing a traumatic event) also fall under the scope of social stress. The current study determined whether the acute stress response and susceptibility to stress-related consequences differed based on whether the stressor consisted of physical versus purely psychological social stress. Using a modified resident-intruder paradigm, male rats were either directly exposed to repeated social defeat stress (intruder) or witnessed a male rat being defeated. Cardiovascular parameters, behavioral anhedonia, and inflammatory cytokines in plasma and the stress-sensitive locus coeruleus were compared between intruder, witness, and control rats. Surprisingly intruders and witnesses exhibited nearly identical increases in mean arterial pressure and heart rate during acute and repeated stress exposures, yet only intruders exhibited stress-induced arrhythmias. Furthermore, re-exposure to the stress environment in the absence of the resident produced robust pressor and tachycardic responses in both stress conditions indicating the robust and enduring nature of social stress. In contrast, the long-term consequences of these stressors were distinct. Intruders were characterized by enhanced inflammatory sensitivity in plasma, while witnesses were characterized by the emergence of depressive-like anhedonia, transient increases in systolic blood pressure and plasma levels of tissue inhibitor of metalloproteinase. The current study highlights that while the acute cardiovascular responses to stress were identical between intruders and witnesses, these stressors produced distinct differences in the enduring consequences to stress, suggesting that witness stress may be more likely to produce long-term cardiovascular

  15. Associations between life stress and subclinical cardiovascular disease are partly mediated by depressive and anxiety symptoms

    NARCIS (Netherlands)

    Bomhof-Roordink, Hanna; Seldenrijk, Adrie; van Hout, Hein P. J.; van Marwijk, Harm W. J.; Diamant, Michaela; Penninx, Brenda W. J. H.

    Background: Stress experienced during childhood or adulthood has been associated with cardiovascular disease (CVD), but it is not clear whether associations are already prevalent on a subclinical cardiovascular level. This study investigates associations between indicators of life stress and

  16. Quantitative characterization of myocardial infarction by cardiovascular magnetic resonance predicts future cardiovascular events in patients with ischemic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Pauly John M

    2008-04-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance (CMR can provide quantitative data of the myocardial tissue utilizing high spatial and temporal resolution along with exquisite tissue contrast. Previous studies have correlated myocardial scar tissue with the occurrence of ventricular arrhythmia. This study was conducted to evaluate whether characterization of myocardial infarction by CMR can predict cardiovascular events in patients with ischemic cardiomyopathy (ICM. Results We consecutively studied 86 patients with ICM (LVEF Conclusion Quantification of the scar volume and scar percentage by CMR is superior to LVEDV, LVESV, and LVEF in prognosticating the future likelihood of the development of cardiovascular events in patients with ICM.

  17. Correlation of chronic kidney disease, diabetes and peripheral artery disease with cardiovascular events in patients using stress myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Furuhashi, Tatsuhiko; Masai, Hirofumi; Kunimasa, Taeko; Nakazato, Ryo; Fukuda, Hiroshi; Sugi, Kaoru; Moroi, Masao

    2011-01-01

    Normal stress myocardial perfusion imaging (MPI) studies generally suggest an excellent prognosis for cardiovascular events. Chronic kidney disease (CKD), diabetes and peripheral artery disease (PAD) have been established as the risk factors for cardiovascular events. However, whether these risk factors significantly predict cardiovascular events in patients with normal stress MPI is unclear. The purpose of this study was to evaluate the prognostic value of these risk factors in patients with normal stress MPI. Patients with normal stress MPI (n=372, male=215 and female=157, age=69 years, CKD without hemodialysis=95, diabetes=99, PAD=19, previous coronary artery disease=116) were followed up for 14 months. Normal stress MPI was defined as a summed stress score of 2 and/or persistent proteinuria. Cardiovascular events included cardiac death, non-fatal myocardial infarction and congestive heart failure requiring hospitalization. Cardiovascular events occurred in 20 of 372 patients (5.4%). In univariate Cox regression analysis, PAD, diabetes, diabetic retinopathy, insulin use, anemia, hypoalbuminemia, CKD, left ventricular ejection fraction and pharmacological stress tests were significant predictors of cardiovascular events. In multivariate Cox regression analysis, PAD, diabetes and CKD were independent and significant predictors for cardiovascular events, and their number was the strongest predictor for cardiovascular events (hazard ratio=21.7, P<0.001). PAD, diabetes and CKD are coexisting, independent and significant risk factors for cardiovascular events, CKD being the strongest predictor. The number of coexisting risk factors is important in predicting cardiovascular events in patients with normal stress MPI. (author)

  18. Complex-Spectrum Magnetic Environment enhances and/or modifies Bioeffects of Hypokinetic Stress Condition: an Animal Study

    Science.gov (United States)

    Temuriantz, N. A.; Martinyuk, V. S.; Ptitsyna, N. G.; Villoresi, G.; Iucci, N.; Tyasto, M. I.; Dorman, L. I.

    During last decades it was shown by many authors that ultra-low and extremely low frequency electric and magnetic fields ULF 0-10 Hz ELF 10-1000 Hz may produce biological effects and consequently may be a possible source for health problems Spaceflight electric and magnetic environments are characterized by complex combination of static and time-varying components in ULF-ELF range and by high variability The objective of this study was to investigate the possible influence of such magnetic fields on rats to understand the pathway regarding functional state of cardiovascular system Magnetic field MF pattern with variable complex spectra in 0-150 Hz frequency range was simulated using 3-axial Helmholtz coils and special computer-based equipment The effect of the real world MF exposure on rats was also tested in combination with hypokinetic stress condition which is typical for spaceflights It was revealed that variable complex-spectrum MF acts as a weak or moderate stress-like factor which amplifies and or modifies the functional shifts caused by other stress-factors The value and direction of the functional shifts caused by MF exposure significantly depend on gender individual-typological constitutional features and also on the physiological state norm stress of organism Our results support the idea that variable complex-spectrum MF action involves sympathetic activation overload in cholesterol transport in blood and also secretor activation of tissue basophyls mast cells that can influence the regional haemodynamics These

  19. Dobutamine stress MRI. Part I. Safety and feasibility of dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia

    International Nuclear Information System (INIS)

    Kuijpers, Dirkjan; Janssen, Caroline H.C.; Oudkerk, Matthijs; Dijkman, Paul R.M. van

    2004-01-01

    The aim of the study was to evaluate safety and feasibility of dobutamine cardiovascular magnetic resonance (CMR) in patients with proven or suspected coronary artery disease. Dobutamine CMR was evaluated retrospectively in 400 consecutive patients with suspicion of myocardial ischemia. Dobutamine was infused using an incremental protocol up to 40 μg/kg body weight per minute. All anti-anginal medication was stopped 4 days before the CMR study and infusion time of dobutamine was 6 min per stage. Hemodynamic data, CMR findings and side effects were reported. Patients with contraindications to CMR (metallic implants and claustrophobia) were excluded from analysis. Dobutamine CMR was successfully performed in 355 (89%) patients. Forty-five (11%) patients could not be investigated adequately because of non-cardiac side effects in 29 (7%) and cardiac side effects in 16 (4%) patients. Hypotension (1.5%) and arrhythmias (1%) were the most frequent cardiac side effects. One patient developed a severe complication (ventricular fibrillation) at the end of the study. There were no myocardial infarctions or fatal complications of the stress test. The most frequent non-cardiac side effects were nausea, vomiting and claustrophobia. Age >70 years, prior myocardial infarction and rest wall motion abnormalities showed no significant differences with side effects (P>0.05). Dobutamine CMR is safe and feasible in patients with suspicion of myocardial ischemia. (orig.)

  20. Dobutamine stress MRI. Part I. Safety and feasibility of dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia.

    Science.gov (United States)

    Kuijpers, Dirkjan; Janssen, Caroline H C; van Dijkman, Paul R M; Oudkerk, Matthijs

    2004-10-01

    The aim of the study was to evaluate safety and feasibility of dobutamine cardiovascular magnetic resonance (CMR) in patients with proven or suspected coronary artery disease. Dobutamine CMR was evaluated retrospectively in 400 consecutive patients with suspicion of myocardial ischemia. Dobutamine was infused using an incremental protocol up to 40 microg/kg body weight per minute. All anti-anginal medication was stopped 4 days before the CMR study and infusion time of dobutamine was 6 min per stage. Hemodynamic data, CMR findings and side effects were reported. Patients with contraindications to CMR (metallic implants and claustrophobia) were excluded from analysis. Dobutamine CMR was successfully performed in 355 (89%) patients. Forty-five (11%) patients could not be investigated adequately because of non-cardiac side effects in 29 (7%) and cardiac side effects in 16 (4%) patients. Hypotension (1.5%) and arrhythmias (1%) were the most frequent cardiac side effects. One patient developed a severe complication (ventricular fibrillation) at the end of the study. There were no myocardial infarctions or fatal complications of the stress test. The most frequent non-cardiac side effects were nausea, vomiting and claustrophobia. Age >70 years, prior myocardial infarction and rest wall motion abnormalities showed no significant differences with side effects (P>0.05). Dobutamine CMR is safe and feasible in patients with suspicion of myocardial ischemia. Copyright 2004 Springer-Verlag

  1. Dobutamine stress MRI. Part I. Safety and feasibility of dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Kuijpers, Dirkjan [State University and Academic Hospital Groningen, Department of Radiology, Groningen (Netherlands); Bronovo Hospital, Department of Radiology and Cardiology, Bronovolaan 1, P.O. Box 96900, The Hague (Netherlands); Janssen, Caroline H.C.; Oudkerk, Matthijs [State University and Academic Hospital Groningen, Department of Radiology, Groningen (Netherlands); Dijkman, Paul R.M. van [Bronovo Hospital, Department of Radiology and Cardiology, Bronovolaan 1, P.O. Box 96900, The Hague (Netherlands)

    2004-10-01

    The aim of the study was to evaluate safety and feasibility of dobutamine cardiovascular magnetic resonance (CMR) in patients with proven or suspected coronary artery disease. Dobutamine CMR was evaluated retrospectively in 400 consecutive patients with suspicion of myocardial ischemia. Dobutamine was infused using an incremental protocol up to 40 {mu}g/kg body weight per minute. All anti-anginal medication was stopped 4 days before the CMR study and infusion time of dobutamine was 6 min per stage. Hemodynamic data, CMR findings and side effects were reported. Patients with contraindications to CMR (metallic implants and claustrophobia) were excluded from analysis. Dobutamine CMR was successfully performed in 355 (89%) patients. Forty-five (11%) patients could not be investigated adequately because of non-cardiac side effects in 29 (7%) and cardiac side effects in 16 (4%) patients. Hypotension (1.5%) and arrhythmias (1%) were the most frequent cardiac side effects. One patient developed a severe complication (ventricular fibrillation) at the end of the study. There were no myocardial infarctions or fatal complications of the stress test. The most frequent non-cardiac side effects were nausea, vomiting and claustrophobia. Age >70 years, prior myocardial infarction and rest wall motion abnormalities showed no significant differences with side effects (P>0.05). Dobutamine CMR is safe and feasible in patients with suspicion of myocardial ischemia. (orig.)

  2. Neuroendocrine and cardiovascular reactions to acute psychological stress are attenuated in smokers

    NARCIS (Netherlands)

    Ginty, Annie T.; Jones, Alexander; Carroll, Douglas; Roseboom, Tessa J.; Phillips, Anna C.; Painter, Rebecca; de Rooij, Susanne R.

    2014-01-01

    A number of studies have now examined the association between smoking and the magnitude of physiological reactions to acute psychological stress. However, no large-scale study has demonstrated this association incorporating neuroendocrine in addition to cardiovascular reactions to stress. The

  3. Cardiovascular magnetic resonance imaging of hypoplastic left heart syndrome in children

    International Nuclear Information System (INIS)

    Dillman, Jonathan R.; Hernandez, Ramiro J.; Dorfman, Adam L.; Attili, Anil K.; Agarwal, Prachi P.; Mueller, Gisela C.; Bell, Aaron

    2010-01-01

    Cardiovascular magnetic resonance imaging (CMR) plays an important complementary role to echocardiography and conventional angiography in the evaluation of hypoplastic left heart syndrome. This imaging modality is particularly useful for assessing cardiovascular postsurgical changes, extracardiac vascular anatomy, ventricular and valvular function, and a variety of complications. The purpose of this article is to provide a contemporary review of the role of CMR in the management of untreated and surgically palliated hypoplastic left heart syndrome in children. (orig.)

  4. Cardiovascular magnetic resonance in carotid atherosclerotic disease

    Directory of Open Access Journals (Sweden)

    Chen Huijun

    2009-12-01

    Full Text Available Abstract Atherosclerosis is a chronic, progressive, inflammatory disease affecting many vascular beds. Disease progression leads to acute cardiovascular events such as myocardial infarction, stroke and death. The diseased carotid alone is responsible for one third of the 700,000 new or recurrent strokes occurring yearly in the United States. Imaging plays an important role in the management of atherosclerosis, and cardiovascular magnetic resonance (CMR of the carotid vessel wall is one promising modality in the evaluation of patients with carotid atherosclerotic disease. Advances in carotid vessel wall CMR allow comprehensive assessment of morphology inside the wall, contributing substantial disease-specific information beyond luminal stenosis. Although carotid vessel wall CMR has not been widely used to screen for carotid atherosclerotic disease, many trials support its potential for this indication. This review summarizes the current state of knowledge regarding carotid vessel wall CMR and its potential clinical application for management of carotid atherosclerotic disease.

  5. Effect of magnetic attachment with stress breaker on lateral stress to abutment tooth under overdenture.

    Science.gov (United States)

    Gonda, T; Ikebe, K; Ono, T; Nokubi, T

    2004-10-01

    Recently, a newly developed magnetic attachment with stress breaker was used in retentive components in overdentures. Excessive lateral stress has a more harmful effect on natural teeth than axial stress, and the magnetic attachment with stress breaker is expected to reduce lateral forces on abutment teeth and protect it teeth from excessive stress. However, the properties of this retainer have not yet been determined experimentally. This study compares the lateral forces on abutment teeth for three retainers under loading on the denture base in a model study. A mandibular simulation model is constructed to measure lateral stress. Three types of retentive devices are attached to the canine root. These devices include the conventional root coping, the conventional magnetic attachment and the new magnetic attachment with stress breaker. For each retentive device, load is generated on the occlusal table of the model overdenture, and the lateral stress on the canine root and the displacement of the overdenture measured. The magnetic attachment with stress breaker does not displace the denture and exhibits lower lateral stress in the canine root than conventional root coping and magnetic attachments.

  6. A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets

    Directory of Open Access Journals (Sweden)

    Dongge Deng

    2016-10-01

    Full Text Available A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

  7. Oxidative stress in cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Shyamal K Goswami

    2015-01-01

    Full Text Available Oxidative stress caused by various oxygen containing free radicals and reactive species (collectively called "Reactive Oxygen Species" or ROS has long been attributed to cardiovascular diseases. In human body, major oxidizing species are super oxide, hydrogen peroxide, hydroxyl radical, peroxy nitrite etc. ROS are produced from distinct cellular sources, enzymatic and non-enzymatic; have specific physicochemical properties and often have specific cellular targets. Although early studies in nineteen sixties and seventies highlighted the deleterious effects of these species, later it was established that they also act as physiological modulators of cellular functions and diseases occur only when ROS production is deregulated. One of the major sources of cellular ROS is Nicotinamide adenine dinucleotide phosphate oxidases (Noxes that are expressed in almost all cell types. Superoxide and hydrogen peroxide generated from them under various conditions act as signal transducers. Due to their immense importance in cellular physiology, various Nox inhibitors are now being developed as therapeutics. Another free radical of importance in cardiovascular system is nitric oxide (a reactive nitrogen species generated from nitric oxide synthase(s. It plays a critical role in cardiac function and its dysregulated generation along with superoxide leads to the formation of peroxynitrite a highly deleterious agent. Despite overwhelming evidences of association between increased level of ROS and cardiovascular diseases, antioxidant therapies using vitamins and omega 3 fatty acids have largely been unsuccessful till date. Also, there are major discrepancies between studies with laboratory animals and human trials. It thus appears that the biology of ROS is far complex than anticipated before. A comprehensive understanding of the redox biology of diseases is thus needed for developing targeted therapeutics.

  8. Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

    Science.gov (United States)

    Reddy, Sahadev T; Thai, Ngoc L; Fakhri, Asghar A; Oliva, Jose; Tom, Kusum B; Dishart, Michael K; Doyle, Mark; Yamrozik, June A; Williams, Ronald B; Grant, Saundra B; Poydence, Jacqueline; Shah, Moneal; Singh, Anil; Nathan, Swami; Biederman, Robert W W

    2013-11-15

    Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a "one-stop shop" in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6-40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. In this proof-of-concept study, it

  9. Highlights of the 16th annual scientific sessions of the Society for Cardiovascular Magnetic Resonance.

    Science.gov (United States)

    Carpenter, John-Paul; Patel, Amit R; Fernandes, Juliano Lara

    2013-07-19

    The 16th Annual Scientific Sessions of the Society for Cardiovascular Magnetic Resonance (SCMR) took place in San Francisco, USA at the end of January 2013. With a faculty of experts from across the world, this congress provided a wealth of insight into cutting-edge research and technological development. This review article intends to provide a highlight of what represented the most significant advances in the field of cardiovascular magnetic resonance (CMR) during this year's meeting.

  10. Neuropeptide Y stimulation as primary target for preventive measures of maladaptative cardiovascular reactions in occupational chronic stress exposure.

    Science.gov (United States)

    Ciumaşu-Rîmbu, Mălina; Popa, Livia; Vulpoi, Carmen

    2012-01-01

    Chronic stress may produce a decrease in central NPY expression and subjects exposed to it may prove hypersensitivity to a novel stressor with dysfunctions in the NPY system and cardiovascular maladaptation to stress, even hypertension. Upregulation of NPY expression may contribute to successful behavioral adaptation to stress by reducing cardiovascular tone and suppressing anxious behaviors. Adaptogens, a new class of metabolic regulators stimulate NPY expression and release. The aim of this study is to increase tolerance and adaptation to stress of hypersensitive to novel stressor, occupational chronic stress exposed subjects with cardiovascular maladaptation to mild new stressor using adaptogens as part of prevention protocol. 40 military personnel with known cardiostressor reactional mode and occupational chronic stress exposure were exposed to mild novel stressor: occupational medicine routine evaluation and clinically assessed for maladaptative cardiovascular response prior and before application of 30 day prevention protocol. Employees were randomly split in two groups, one receiving standard prevention protocol (lifestyle counseling) plus adaptogens in multiple dose administration, twice daily and the other receiving only standard prevention protocol. We found significant statistic differences in all cardiovascular parameters in adaptogen group and only in diastolic blood pressure in control group. Adaptogens could be an important factor in successful prevention protocols of chronic occupational stress dysfunctions involving NPY systems.

  11. Cardiovascular Magnetic Resonance in Cardiology Practice: A Concise Guide to Image Acquisition and Clinical Interpretation.

    Science.gov (United States)

    Valbuena-López, Silvia; Hinojar, Rocío; Puntmann, Valentina O

    2016-02-01

    Cardiovascular magnetic resonance plays an increasingly important role in routine cardiology clinical practice. It is a versatile imaging modality that allows highly accurate, broad and in-depth assessment of cardiac function and structure and provides information on pertinent clinical questions in diseases such as ischemic heart disease, nonischemic cardiomyopathies, and heart failure, as well as allowing unique indications, such as the assessment and quantification of myocardial iron overload or infiltration. Increasing evidence for the role of cardiovascular magnetic resonance, together with the spread of knowledge and skill outside expert centers, has afforded greater access for patients and wider clinical experience. This review provides a snapshot of cardiovascular magnetic resonance in modern clinical practice by linking image acquisition and postprocessing with effective delivery of the clinical meaning. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  12. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    International Nuclear Information System (INIS)

    Huang, Haihong; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-01-01

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, H p (y), induced by applied magnetic fields with different intensities measured through the tensile tests. The H p (y), its slope coefficient K S and maximum gradient K max changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of H p (y) and its slope coefficient K S increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, H p (y) and K S reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of H p (y) instead of changing the signal curve′s profile; and the magnitude of H p (y), K S , K max and the change rate of K S increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials. - Highlights: • We investigated how applied magnetic field and tensile stress impact H p (y) signals. • Magnitude of H p (y), K S and K max increase with the increase of applied magnetic field. • Both applied magnetic field and tensile stress impact material magnetic permeability. • Applied magnetic field can help to evaluate the stress distribution of components.

  13. Cardiovascular magnetic resonance frontiers: Tissue characterisation with mapping

    OpenAIRE

    Schofield, R.; Bhuva, A.; Manacho, K.; Moon, J. C.

    2016-01-01

    The clinical use of cardiovascular magnetic resonance (CMR) imaging has expanded rapidly over the last decade. Its role in cardiac morphological and functional assessment is established, with perfusion and late gadolinium enhancement (LGE) imaging for scar increasingly used in day-to-day clinical decision making. LGE allows a virtual histological assessment of the myocardium, with the pattern of scar suggesting disease aetiology, and the extent of predicting risk. However, even combined, the ...

  14. Cardiovascular Responses to Psychosocial Stress Reflect Motivation State in Adults Born at Extremely Low Birth Weight

    Directory of Open Access Journals (Sweden)

    Karen J. Mathewson PhD

    2015-03-01

    Full Text Available Background. Adults born extremely preterm appear to have more difficulty managing the stresses of early adulthood than their term-born peers. Objective. To examine the effects of being born at extremely low birth weight (ELBW; birth weight < 1000 g versus at full term on cardiovascular responses to stress. Method. Cardiovascular responses were elicited during administration of a widely used laboratory stressor, the Trier Social Stress Test (TSST. Results. Term-born adults exhibited a larger decrease in total peripheral resistance and larger increase in cardiac output for TSST performance, reflecting greater resilience, than did ELBW adults. Furthermore, in ELBW participants but not controls, cardiovascular responses were correlated with anxiety, suggesting that their responses reflected feelings of stress. Conclusions. Skills-training and practice with relevant stressors may be necessary to increase the personal resources of ELBW participants for managing stress as they transition to adulthood.

  15. Cardiovascular responses to cognitive stress in patients with migraine and tension-type headache

    Directory of Open Access Journals (Sweden)

    Nilsen Kristian B

    2007-08-01

    Full Text Available Abstract Background The purpose of this study was to investigate the temporal relationship between autonomic changes and pain activation in migraine and tension-type headache induced by stress in a model relevant for everyday office-work. Methods We measured pain, blood pressure (BP, heart rate (HR and skin blood flow (BF during and after controlled low-grade cognitive stress in 22 migraineurs during headache-free periods, 18 patients with tension-type headache (TTH and 44 healthy controls. The stress lasted for one hour and was followed by 30 minutes of relaxation. Results Cardiovascular responses to cognitive stress in migraine did not differ from those in control subjects. In TTH patients HR was maintained during stress, whereas it decreased for migraineurs and controls. A trend towards a delayed systolic BP response during stress was also observed in TTH. Finger BF recovery was delayed after stress and stress-induced pain was associated with less vasoconstriction in TTH during recovery. Conclusion It is hypothesized that TTH patients have different stress adaptive mechanisms than controls and migraineurs, involving delayed cardiovascular adaptation and reduced pain control system inhibition.

  16. Cardiovascular magnetic resonance activity in the United Kingdom: a survey on behalf of the british society of cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Dargie Henry J

    2011-10-01

    Full Text Available Abstract Background The indications, complexity and capabilities of cardiovascular magnetic resonance (CMR have rapidly expanded. Whether actual service provision and training have developed in parallel is unknown. Methods We undertook a systematic telephone and postal survey of all public hospitals on behalf of the British Society of Cardiovascular Magnetic Resonance to identify all CMR providers within the United Kingdom. Results Of the 60 CMR centres identified, 88% responded to a detailed questionnaire. Services are led by cardiologists and radiologists in equal proportion, though the majority of current trainees are cardiologists. The mean number of CMR scans performed annually per centre increased by 44% over two years. This trend was consistent across centres of different scanning volumes. The commonest indication for CMR was assessment of heart failure and cardiomyopathy (39%, followed by coronary artery disease and congenital heart disease. There was striking geographical variation in CMR availability, numbers of scans performed, and distribution of trainees. Centres without on site scanning capability refer very few patients for CMR. Just over half of centres had a formal training programme, and few performed regular audit. Conclusion The number of CMR scans performed in the UK has increased dramatically in just two years. Trainees are mainly located in large volume centres and enrolled in cardiology as opposed to radiology training programmes.

  17. Neuroendocrine and oxidoreductive mechanisms of stress-induced cardiovascular diseases.

    Science.gov (United States)

    Pajović, S B; Radojcić, M B; Kanazir, D T

    2008-01-01

    The review concerns a number of basic molecular pathways that play a crucial role in perception, transmission, and modulation of the stress signals, and mediate the adaptation of the vital processes in the cardiovascular system (CVS). These highly complex systems for intracellular transfer of information include stress hormones and their receptors, stress-activated phosphoprotein kinases, stress-activated heat shock proteins, and antioxidant enzymes maintaining oxidoreductive homeostasis of the CVS. Failure to compensate for the deleterious effects of stress may result in the development of different pathophysiological states of the CVS, such as ischemia, hypertension, atherosclerosis and infarction. Stress-induced dysbalance in each of the CVS molecular signaling systems and their contribution to the CVS malfunctioning is reviewed. The general picture of the molecular mechanisms of the stress-induced pathophysiology in the CVS pointed out the importance of stress duration and intensity as etiological factors, and suggested that future studies should be complemented by the careful insights into the individual factors of susceptibility to stress, prophylactic effects of 'healthy' life styles and beneficial action of antioxidant-rich nutrition.

  18. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haihong, E-mail: huanghaihong@hfut.edu.cn; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-10-15

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, H{sub p}(y), induced by applied magnetic fields with different intensities measured through the tensile tests. The H{sub p}(y), its slope coefficient K{sub S} and maximum gradient K{sub max} changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of H{sub p}(y) and its slope coefficient K{sub S} increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, H{sub p}(y) and K{sub S} reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of H{sub p}(y) instead of changing the signal curve′s profile; and the magnitude of H{sub p}(y), K{sub S}, K{sub max} and the change rate of K{sub S} increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials. - Highlights: • We investigated how applied magnetic field and tensile stress impact H{sub p}(y) signals. • Magnitude of H{sub p}(y), K{sub S} and K{sub max} increase with the increase of applied magnetic field. • Both applied magnetic field and tensile stress impact material magnetic permeability. • Applied magnetic field can help to evaluate the stress distribution of components.

  19. The role of psychosocial stress at work for the development of cardiovascular diseases: a systematic review.

    Science.gov (United States)

    Backé, Eva-Maria; Seidler, Andreas; Latza, Ute; Rossnagel, Karin; Schumann, Barbara

    2012-01-01

    A systematic review was carried out to assess evidence for the association between different models of stress at work, and cardiovascular morbidity and mortality. A literature search was conducted using five databases (MEDLINE, Cochrane Library, EMBASE, PSYNDEX and PsycINFO). Inclusion criteria for studies were the following: self-reported stress for individual workplaces, prospective study design and incident disease (myocardial infarction, stroke, angina pectoris, high blood pressure). Evaluation, according to the criteria of the Scottish Intercollegiate Guidelines Network, was done by two readers. In case of disagreement, a third reader was involved. Twenty-six publications were included, describing 40 analyses out of 20 cohorts. The risk estimates for work stress were associated with a statistically significant increased risk of cardiovascular disease in 13 out of the 20 cohorts. Associations were significant for 7 out of 13 cohorts applying the demand-control model, all three cohorts using the effort-reward model and 3 out of 6 cohorts investigating other models. Most significant results came from analyses considering only men. Results for the association between job stress and cardiovascular diseases in women were not clear. Associations were weaker in participants above the age of 55. In accordance with other systematic reviews, this review stresses the importance of psychosocial factors at work in the aetiology of cardiovascular diseases. Besides individual measures to manage stress and to cope with demanding work situations, organisational changes at the workplace need to be considered to find options to reduce occupational risk factors for cardiovascular diseases.

  20. Technological Innovations in Magnetic Resonance for Early Detection of Cardiovascular Diseases.

    Science.gov (United States)

    Santarelli, Maria F; Positano, Vincenzo; Martini, Nicola; Valvano, Giuseppe; Landini, Luigi

    2016-01-01

    Most recent technical innovations in cardiovascular MR imaging (CMRI) are presented in this review. They include hardware and software developments, and novelties in parametric mapping. All these recent improvements lead to high spatial and temporal resolution and quantitative information on the heart structure and function. They make it achievable ambitious goals in the field of magnetic resonance, such as the early detection of cardiovascular pathologies. In this review article, we present recent innovations in CMRI, emphasizing the progresses performed and the solutions proposed to some yet opened technical problems.

  1. Work Stress as a Risk Factor for Cardiovascular Disease.

    Science.gov (United States)

    Kivimäki, Mika; Kawachi, Ichiro

    2015-09-01

    The role of psychosocial work stress as a risk factor for chronic disease has been the subject of considerable debate. Many researchers argue in support of a causal connection while others remain skeptical and have argued that the effect on specific health conditions is either negligible or confounded. This review of evidence from over 600,000 men and women from 27 cohort studies in Europe, the USA and Japan suggests that work stressors, such as job strain and long working hours, are associated with a moderately elevated risk of incident coronary heart disease and stroke. The excess risk for exposed individuals is 10-40 % compared with those free of such stressors. Differences between men and women, younger versus older employees and workers from different socioeconomic backgrounds appear to be small, indicating that the association is robust. Meta-analyses of a wider range of health outcomes show additionally an association between work stress and type 2 diabetes, though not with common cancers or chronic obstructive pulmonary disease, suggesting outcome specificity. Few studies have addressed whether mitigation of work stressors would reduce the risk of cardiovascular disease. In view of the limited interventional evidence on benefits, harms and cost-effectiveness, definitive recommendations have not been made (e.g. by the US Preventive Services Taskforce) for the primary prevention of cardiovascular disease via workplace stress reduction. Nevertheless, governments are already launching healthy workplace campaigns, and preventing excessive work stress is a legal obligation in several countries. Promoting awareness of the link between stress and health among both employers and workers is an important component of workplace health promotion.

  2. Cardiovascular magnetic resonance in hypertrophic cardiomyopathy and infiltrative cardiomyopathy

    OpenAIRE

    Schofield, Rebecca; Manacho, Katia; Castelletti, Silvia; Moon, James C.

    2016-01-01

    Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. Cardiac imaging plays a key role in the diagnosis and management, with cardiovascular magnetic resonance (CMR) an important modality. CMR provides a number of different techniques in one examination: structure and function, flow imaging and tissue characterisation particularly with the late gadolinium enhancement (LGE) technique. Other techniques include vasodilator perfusion, mapping (especially T1 mapping and ex...

  3. Post-traumatic Stress Disorder and Cardiovascular Disease.

    Science.gov (United States)

    Burg, Matthew M; Soufer, Robert

    2016-10-01

    Post-traumatic stress disorder (PTSD) is a disabling condition that develops consequent to trauma exposure such as natural disasters, sexual assault, automobile accidents, and combat that independently increases risk for early incident cardiovascular disease (CVD) and cardiovascular (CV) mortality by over 50 % and incident hypertension risk by over 30 %. While the majority of research on PTSD and CVD has concerned initially healthy civilian and military veteran samples, emerging research is also demonstrating that PTSD consequent to the trauma of an acute cardiac event significantly increases risk for early recurrence and mortality and that patient experiences in the clinical pathway that are related to the emergency department environment may provide an opportunity to prevent PTSD onset and thus improve outcomes. Future directions for clinical and implementation science concern broad PTSD and trauma screening in the context of primary care medical environments and the testing of PTSD treatments with CVD-related surrogates and endpoints.

  4. Cardiovascular reactions to psychological stress and abuse history: the role of occurrence, frequency, and type of abuse.

    Science.gov (United States)

    Ginty, Annie T; Masters, Nicole A; Nelson, Eliza B; Kaye, Karen T; Conklin, Sarah M

    2017-03-01

    Extreme cardiovascular reactions to psychological stress have been associated with traumatic life experiences. Previous studies have focused on the occurrence or frequency of abuse rather than type of abuse. We examined how occurrence, frequency, and the type of abuse history are related to cardiovascular reactivity (CVR) to acute psychological stress. The study consisted of between group and continuous analyses to examine the association between occurrence, type, and frequency of abuse with cardiovascular reactions to acute psychological stress. Data from 64 participants were collected. Heart rate, systolic blood pressure, and diastolic blood pressure were measured at baseline and during a standard mental arithmetic stress task. Individuals who experienced abuse showed diminished CVR to acute psychological stress; this was driven specifically by the history of sexual abuse. Frequency of abuse did not relate to stress reactions. These findings accord with previous work suggesting a relationship between traumatic life experience and hypoarousal in physiological reactivity and extend previous findings by suggesting the relationship may be driven by sexual abuse.

  5. Cardiovascular Mitochondrial Dysfunction Induced by Cocaine: Biomarkers and Possible Beneficial Effects of Modulators of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Manuela Graziani

    2017-01-01

    Full Text Available Cocaine abuse has long been known to cause morbidity and mortality due to its cardiovascular toxic effects. The pathogenesis of the cardiovascular toxicity of cocaine use has been largely reviewed, and the most recent data indicate a fundamental role of oxidative stress in cocaine-induced cardiovascular toxicity, indicating that mitochondrial dysfunction is involved in the mechanisms of oxidative stress. The comprehension of the mechanisms involving mitochondrial dysfunction could help in selecting the most appropriate mitochondria injury biological marker, such as superoxide dismutase-2 activity and glutathionylated hemoglobin. The potential use of modulators of oxidative stress (mitoubiquinone, the short-chain quinone idebenone, and allopurinol in the treatment of cocaine cardiotoxic effects is also suggested to promote further investigations on these potential mitochondria-targeted antioxidant strategies.

  6. 2D magnetization of grain-oriented 3%-Si steel under uniaxial stress

    International Nuclear Information System (INIS)

    Permiakov, V.; Dupre, L.; Pulnikov, A.; Melkebeek, J.

    2005-01-01

    Magnetization in electrical steels is strongly affected by mechanical stress. The stress dependence of magnetic properties of non-oriented steels has been studied at one- and two-dimensional magnetization. This paper deals with the stress effect on one- and two-dimensional magnetization in grain-oriented 3%-Si steel. The special magnetic measurements system is applied to combine uniaxial stress and 2D magnetic measurements. The uniaxial stress ranges from 10 MPa compressive stress to 100 MPa tensile stress. A domain theory is a suitable tool for prediction and a physical explanation of stress dependency in grain-oriented steel

  7. Dependence of magnetic permeability on residual stresses in alloyed steels

    Directory of Open Access Journals (Sweden)

    E. Hristoforou

    2018-04-01

    Full Text Available A method for the monitoring of residual stress distribution in steels has been developed based on non-destructive surface magnetic permeability measurements. In order to investigate the potential utilization of the magnetic method in evaluating residual stresses, the magnetic calibration curves of various ferromagnetic alloyed steels’ grade (AISI 4140, TRIP and Duplex were examined. X-Ray diffraction technique was used for determining surface residual stress values. The overall measurement results have shown that the residual stress determined by the magnetic method was in good agreement with the diffraction results. Further experimental investigations are required to validate the preliminary results and to verify the presence of a unique normalized magnetic stress calibration curve.

  8. Dependence of magnetic permeability on residual stresses in alloyed steels

    Science.gov (United States)

    Hristoforou, E.; Ktena, A.; Vourna, P.; Argiris, K.

    2018-04-01

    A method for the monitoring of residual stress distribution in steels has been developed based on non-destructive surface magnetic permeability measurements. In order to investigate the potential utilization of the magnetic method in evaluating residual stresses, the magnetic calibration curves of various ferromagnetic alloyed steels' grade (AISI 4140, TRIP and Duplex) were examined. X-Ray diffraction technique was used for determining surface residual stress values. The overall measurement results have shown that the residual stress determined by the magnetic method was in good agreement with the diffraction results. Further experimental investigations are required to validate the preliminary results and to verify the presence of a unique normalized magnetic stress calibration curve.

  9. Endurance- and Resistance-Trained Men Exhibit Lower Cardiovascular Responses to Psychosocial Stress Than Untrained Men.

    Science.gov (United States)

    Gröpel, Peter; Urner, Maren; Pruessner, Jens C; Quirin, Markus

    2018-01-01

    Evidence shows that regular physical exercise reduces physiological reactivity to psychosocial stress. However, previous research mainly focused on the effect of endurance exercise, with only a few studies looking at the effect of resistance exercise. The current study tested whether individuals who regularly participate in either endurance or resistance training differ from untrained individuals in adrenal and cardiovascular reactivity to psychosocial stress. Twelve endurance-trained men, 10 resistance-trained men, and 12 healthy but untrained men were exposed to a standardized psychosocial stressor, the Trier Social Stress Test. Measurements of heart rate, free salivary cortisol levels, and mood were obtained throughout the test and compared among the three groups. Overall, both endurance- and resistance-trained men had lower heart rate levels than untrained men, indicating higher cardiac performance of the trained groups. Trained men also exhibited lower heart rate responses to psychosocial stress compared with untrained men. There were no significant group differences in either cortisol responses or mood responses to the stressor. The heart rate results are consistent with previous studies indicating reduced cardiovascular reactivity to psychosocial stress in trained individuals. These findings suggest that long-term endurance and resistance trainings may be related to the same cardiovascular benefits, without exhibiting strong effects on the cortisol reactivity to stress.

  10. Hypoxia Stress Test Reveals Exaggerated Cardiovascular Effects in Hypertensive Rats after Exposure to the Air Pollutant Acrolein

    Science.gov (United States)

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in susceptible populations with cardiovascular disease. Stress tests are useful in assessing cardiovascular risk and manifesting latent effects of exposure. The goal of this study w...

  11. A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress

    DEFF Research Database (Denmark)

    Truijen, Jasper; Bundgaard-Nielsen, Morten; van Lieshout, Johannes J

    2010-01-01

    The Frank-Starling mechanism describes the relationship between stroke volume and preload to the heart, or the volume of blood that is available to the heart--the central blood volume. Understanding the role of the central blood volume for cardiovascular control has been complicated by the fact...... stress including bed rest/microgravity, exercise and training, thermal loading, illness, and trauma/haemorrhage is likely to restrict venous return and Q. Consequently the cardiovascular responses are determined primarily by their effect on the central blood volume. Thus during environmental stress, flow...

  12. Potential Contribution of Work-Related Psychosocial Stress to the Development of Cardiovascular Disease and Type II Diabetes: A Brief Review.

    Science.gov (United States)

    Krajnak, Kristine M

    2014-01-01

    Two of the major causes of death worldwide are cardiovascular disease and Type II diabetes. Although death due to these diseases is assessed separately, the physiological process that is attributed to the development of cardiovascular disease can be linked to the development of Type II diabetes and the impact that this disease has on the cardiovascular system. Physiological, genetic, and personal factors contribute to the development of both these disorders. It has also been hypothesized that work-related stress may contribute to the development of Type II diabetes and cardiovascular disease. This review summarizes some of the studies examining the role of work-related stress on the development of these chronic disorders. Because women may be more susceptible to the physiological effects of work-related stress, the papers cited in this review focus on studies that examined the difference in responses of men or women to work-related stress or on studies that focused on the effects of stress on women alone. Based on the papers summarized, it is concluded that (1) work-related stress may directly contribute to the development of cardiovascular disease by inducing increases in blood pressure and changes in heart rate that have negative consequences on functioning of the cardiovascular system; (2) workers reporting increased levels of stress may display an increased risk of Type II diabetes because they adopt poor health habits (ie, increased level of smoking, inactivity etc), which in turn contribute to the development of cardiovascular problems; and (3) women in high demand and low-control occupations report an increased level of stress at work, and thus may be at a greater risk of negative health consequences.

  13. Quantification of right and left ventricular function by cardiovascular magnetic resonance

    International Nuclear Information System (INIS)

    Bellenger, N.G.; Smith, G.C.; Pennell, D.J.; Grothues, F.

    2000-01-01

    Cardiac dysfunction is a major cause of cardiovascular morbidity and mortality. Accurate and reproducible assessment of cardiac function is essential for the diagnosis, the assessment of prognosis and evaluation of a patient's response to therapy. Cardiovascular magnetic resonance (CMR) provides a measure of global and regional function that is not only accurate and reproducible but is noninvasive, free of ionising radiation, and independent of the geometric assumptions and acoustic windows that limit echocardiography. With the advent of faster scanners, automated analysis, increasing availability and reducing costs, CMR is fast becoming a clinically tenable reference standard for the measurement of cardiac function. (orig.) [de

  14. Work stress and cardiovascular disease: a life course perspective.

    Science.gov (United States)

    Li, Jian; Loerbroks, Adrian; Bosma, Hans; Angerer, Peter

    2016-05-25

    Individuals in employment experience stress at work, and numerous epidemiological studies have documented its negative health effects, particularly on cardiovascular disease (CVD). Although evidence on the various interrelationships between work stress and CVD has been accumulated, those observations have not yet been conceptualized in terms of a life course perspective. Using the chain of risk model, we would like to propose a theoretical model incorporating six steps: (1) work stress increases the risk of incident CVD in healthy workers. (2) Among those whose work ability is not fully and permanently damaged, work stress acts as a determinant of the process of return to work after CVD onset. (3) CVD patients experience higher work stress after return to work. (4) Work stress increases the risk of recurrent CVD in workers with prior CVD. (5) CVD patients who fully lose their work ability transit to disability retirement. (6) Disability retirees due to CVD have an elevated risk of CVD mortality. The life course perspective might facilitate an in-depth understanding of the diverse interrelationships between work stress and CVD, thereby leading to work stress management interventions at each period of the lifespan and three-level prevention of CVD.

  15. The Role of Cardiovascular Magnetic Resonance Imaging in Heart Failure.

    Science.gov (United States)

    Peterzan, Mark A; Rider, Oliver J; Anderson, Lisa J

    2016-11-01

    Cardiovascular imaging is key for the assessment of patients with heart failure. Today, cardiovascular magnetic resonance imaging plays an established role in the assessment of patients with suspected and confirmed heart failure syndromes, in particular identifying aetiology. Its role in informing prognosis and guiding decisions around therapy are evolving. Key strengths include its accuracy; reproducibility; unrestricted field of view; lack of radiation; multiple abilities to characterise myocardial tissue, thrombus and scar; as well as unparalleled assessment of left and right ventricular volumes. T2* has an established role in the assessment and follow-up of iron overload cardiomyopathy and a role for T1 in specific therapies for cardiac amyloid and Anderson-Fabry disease is emerging.

  16. Measurement of coronary flow response to cold pressor stress in asymptomatic women with cardiovascular risk factors using spiral velocity-encoded cine MRI at 3 Tesla

    International Nuclear Information System (INIS)

    Maroules, Christopher D.; Peshock, Ronald M.; Chang, Alice Y.; Kontak, Andrew; Dimitrov, Ivan; Kotys, Melanie

    2010-01-01

    Background: Coronary sinus (CS) flow in response to a provocative stress has been used as a surrogate measure of coronary flow reserve, and velocity-encoded cine (VEC) magnetic resonance imaging (MRI) is an established technique for measuring CS flow. In this study, the cold pressor test (CPT) was used to measure CS flow response because it elicits an endothelium-dependent coronary vasodilation that may afford greater sensitivity for detecting early changes in coronary endothelial function. Purpose: To investigate the feasibility and reproducibility of CS flow reactivity (CSFR) to CPT using spiral VEC MRI at 3 Tesla in a sample of asymptomatic women with cardiovascular risk factors. Material and Methods: Fourteen asymptomatic women (age 38 years ± 10) with cardiovascular risk factors were studied using 3D spiral VEC MRI of the CS at 3 T. The CPT was utilized as a provocative stress to measure changes in CS flow. CSFR to CPT was calculated from the ratio of CS flow during peak stress to baseline CS flow. Results: CPT induced a significant hemodynamic response as measured by a 45% increase in rate-pressure product (P<0.01). A significant increase in CS volume flow was also observed (baseline, 116 ± 26 ml/min; peak stress, 152 ± 34 ml/min, P=0.01). CSFR to CPT was 1.31 ± 0.20. Test-retest variability of CS volume flow was 5% at baseline and 6% during peak stress. Conclusion: Spiral CS VEC MRI at 3 T is a feasible and reproducible technique for measuring CS flow in asymptomatic women at risk for cardiovascular disease. Significant changes in CSFR to CPT are detectable, without demanding pharmacologic stress

  17. Magnetic field aberration induced by cycle stress

    International Nuclear Information System (INIS)

    Yang En; Li Luming; Chen Xing

    2007-01-01

    Magneto-mechanical effect has been causing people's growing interest because of its relevance to several technology problems. One of them is the variation of surface magnetic field induced by stress concentration under the geomagnetic field. It can be used as an innovative, simple and convenient potential NDE method, called as magnetic memory method. However, whether and how this can be used as a quantitative measurement method, is still a virginal research field where nobody sets foot in. In this paper, circle tensile stress within the elastic region was applied to ferromagnetic sample under geomagnetic field. Experiment results on the relation between surface magnetic field and elastic stress were presented, and a simple model was derived. Simulation of the model was reconciled with the experimental results. This can be of great importance for it provides a brighter future for the promising Magnetic Memory NDE method-the potential possibility of quantitative measurement

  18. The Metabolic Syndrome, Oxidative Stress, Environment, and Cardiovascular Disease: The Great Exploration

    Science.gov (United States)

    Hutcheson, Rebecca; Rocic, Petra

    2012-01-01

    The metabolic syndrome affects 30% of the US population with increasing prevalence. In this paper, we explore the relationship between the metabolic syndrome and the incidence and severity of cardiovascular disease in general and coronary artery disease (CAD) in particular. Furthermore, we look at the impact of metabolic syndrome on outcomes of coronary revascularization therapies including CABG, PTCA, and coronary collateral development. We also examine the association between the metabolic syndrome and its individual component pathologies and oxidative stress. Related, we explore the interaction between the main external sources of oxidative stress, cigarette smoke and air pollution, and metabolic syndrome and the effect of this interaction on CAD. We discuss the apparent lack of positive effect of antioxidants on cardiovascular outcomes in large clinical trials with emphasis on some of the limitations of these trials. Finally, we present evidence for successful use of antioxidant properties of pharmacological agents, including metformin, statins, angiotensin II type I receptor blockers (ARBs), and angiotensin II converting enzyme (ACE) inhibitors, for prevention and treatment of the cardiovascular complications of the metabolic syndrome. PMID:22829804

  19. The Metabolic Syndrome, Oxidative Stress, Environment, and Cardiovascular Disease: The Great Exploration

    Directory of Open Access Journals (Sweden)

    Rebecca Hutcheson

    2012-01-01

    Full Text Available The metabolic syndrome affects 30% of the US population with increasing prevalence. In this paper, we explore the relationship between the metabolic syndrome and the incidence and severity of cardiovascular disease in general and coronary artery disease (CAD in particular. Furthermore, we look at the impact of metabolic syndrome on outcomes of coronary revascularization therapies including CABG, PTCA, and coronary collateral development. We also examine the association between the metabolic syndrome and its individual component pathologies and oxidative stress. Related, we explore the interaction between the main external sources of oxidative stress, cigarette smoke and air pollution, and metabolic syndrome and the effect of this interaction on CAD. We discuss the apparent lack of positive effect of antioxidants on cardiovascular outcomes in large clinical trials with emphasis on some of the limitations of these trials. Finally, we present evidence for successful use of antioxidant properties of pharmacological agents, including metformin, statins, angiotensin II type I receptor blockers (ARBs, and angiotensin II converting enzyme (ACE inhibitors, for prevention and treatment of the cardiovascular complications of the metabolic syndrome.

  20. Dobutamine stress MRI. Part II. Risk stratification with dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia

    International Nuclear Information System (INIS)

    Kuijpers, Dirkjan; Dijkman, Paul R.M. van; Janssen, Caroline H.C.; Vliegenthart, Rozemarijn; Zijlstra, Felix; Oudkerk, Matthijs

    2004-01-01

    The aim of this study was to determine the prognostic value of dobutamine cardiovascular magnetic resonance (CMR) in patients suspected of myocardial ischemia. Clinical data and dobutamine-CMR results were analyzed in 299 consecutive patients. Follow-up data were analyzed in categories of risk levels defined by the history of coronary artery disease and presence of rest wall motion abnormalities (RWMA). Major adverse cardiac events (MACE) as evaluated end points included cardiac death, nonfatal myocardial infarction and clinically indicated coronary revascularization. Follow-up was completed in 214 (99%) patients with a negative dobutamine-CMR study (no signs of inducible myocardial ischemia) with an average of 24 months. The patients with a negative dobutamine-CMR study and RWMA showed a significantly higher annual MACE rate (18%) than the patients without RWMA (0.56%) (P<0.001). Patients without RWMA showed an annual MACE rate of 2% when they had a history of coronary artery disease and <0.1% without a previous coronary event (P<0.001). Dobutamine-CMR showed a positive and negative predictive value of 95 and 93%, respectively. The cardiovascular occurrence-free survival rate was 96.2%. In patients suspected of myocardial ischemia, dobutamine-CMR is able to assess risk levels for coronary events with high accuracy. (orig.)

  1. Dobutamine stress MRI. Part II. Risk stratification with dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Kuijpers, Dirkjan [State University and Academic Hospital Groningen, Department of Radiology and Cardiology, Groningen (Netherlands); Bronovo Hospital, Department of Radiology and Cardiology, Bronovolaan 1, P.O. Box 96900, The Hague (Netherlands); Dijkman, Paul R.M. van [Bronovo Hospital, Department of Radiology and Cardiology, Bronovolaan 1, P.O. Box 96900, The Hague (Netherlands); Janssen, Caroline H.C.; Vliegenthart, Rozemarijn; Zijlstra, Felix; Oudkerk, Matthijs [State University and Academic Hospital Groningen, Department of Radiology and Cardiology, Groningen (Netherlands)

    2004-11-01

    The aim of this study was to determine the prognostic value of dobutamine cardiovascular magnetic resonance (CMR) in patients suspected of myocardial ischemia. Clinical data and dobutamine-CMR results were analyzed in 299 consecutive patients. Follow-up data were analyzed in categories of risk levels defined by the history of coronary artery disease and presence of rest wall motion abnormalities (RWMA). Major adverse cardiac events (MACE) as evaluated end points included cardiac death, nonfatal myocardial infarction and clinically indicated coronary revascularization. Follow-up was completed in 214 (99%) patients with a negative dobutamine-CMR study (no signs of inducible myocardial ischemia) with an average of 24 months. The patients with a negative dobutamine-CMR study and RWMA showed a significantly higher annual MACE rate (18%) than the patients without RWMA (0.56%) (P<0.001). Patients without RWMA showed an annual MACE rate of 2% when they had a history of coronary artery disease and <0.1% without a previous coronary event (P<0.001). Dobutamine-CMR showed a positive and negative predictive value of 95 and 93%, respectively. The cardiovascular occurrence-free survival rate was 96.2%. In patients suspected of myocardial ischemia, dobutamine-CMR is able to assess risk levels for coronary events with high accuracy. (orig.)

  2. Dobutamine stress MRI. Part II. Risk stratification with dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia.

    Science.gov (United States)

    Kuijpers, Dirkjan; van Dijkman, Paul R M; Janssen, Caroline H C; Vliegenthart, Rozemarijn; Zijlstra, Felix; Oudkerk, Matthijs

    2004-11-01

    The aim of this study was to determine the prognostic value of dobutamine cardiovascular magnetic resonance (CMR) in patients suspected of myocardial ischemia. Clinical data and dobutamine-CMR results were analyzed in 299 consecutive patients. Follow-up data were analyzed in categories of risk levels defined by the history of coronary artery disease and presence of rest wall motion abnormalities (RWMA). Major adverse cardiac events (MACE) as evaluated end points included cardiac death, nonfatal myocardial infarction and clinically indicated coronary revascularization. Follow-up was completed in 214 (99%) patients with a negative dobutamine-CMR study (no signs of inducible myocardial ischemia) with an average of 24 months. The patients with a negative dobutamine-CMR study and RWMA showed a significantly higher annual MACE rate (18%) than the patients without RWMA (0.56%) ( P<0.001). Patients without RWMA showed an annual MACE rate of 2% when they had a history of coronary artery disease and <0.1% without a previous coronary event ( P<0.001). Dobutamine-CMR showed a positive and negative predictive value of 95 and 93%, respectively. The cardiovascular occurrence-free survival rate was 96.2%. In patients suspected of myocardial ischemia, dobutamine-CMR is able to assess risk levels for coronary events with high accuracy.

  3. Poor habitual sleep efficiency is associated with increased cardiovascular and cortisol stress reactivity in men.

    Science.gov (United States)

    Massar, Stijn A A; Liu, Jean C J; Mohammad, Nabilah B; Chee, Michael W L

    2017-07-01

    Inadequate sleep and psychological stress can both elevate physiological stress markers, such as cortisol. Prior studies that have applied induced psychosocial stress after a night of experimental sleep deprivation have found these effects to be compounded. We examined whether the relationship between stress reactivity and poor sleep also extends to habitual sleep patterns. Fifty-nine adult male participants were recruited. Habitual sleep patterns were monitored with actigraphy for a week. Participants subsequently underwent the Trier Social Stress Test. Cardiovascular responses and salivary cortisol were measured at baseline, during stress, and during recovery. Subjects who showed poor habitual sleep efficiency during the week before stress induction responded with higher stress-related elevations of blood pressure and cortisol levels as compared to subjects with high sleep efficiency. This relationship between poor sleep efficiency and elevated blood pressure persisted during the post-stress recovery period. Similar associations between total sleep time in the week prior to the stress induction and physiological reactivity did not reach significance. Our findings indicate that habitual low sleep efficiency exaggerates cardiovascular and neuroendocrine effects of psychosocial stress, in a male population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. The assessment of Big Five Personality Factors and Temperament Domains as modifiers of cardiovascular response to occupational stress.

    Science.gov (United States)

    Merecz, D; Makowska, Z; Makowiec-Dabrowska, T

    1999-01-01

    The aim of the study was to explore the role of Big Five Personality Factors and Temperament Domains as the factors influencing cardiovascular response to work, and their moderating effect on the relationship between occupational stress and cardiovascular reactivity. The self-reported data on occupational stress and filled in NEO-Five Factor Inventory by Costa, and McCrae and Pavlovian Temperament Survey by Strelau et al. were collected from 97 bank clerks employed in large bank branches. The subjects also responded to the questionnaire on personal and professional background factors. A 24 hour monitoring of cardiovascular reactivity (heart rate and blood pressure) was also provided. Conscientiousness was found to be the only modifier of cardiovascular response to occupational stress reflected by systolic blood pressure. Several main, independent of stress effects of personality and temperament domains were also found. The ratio of heart rate at work to heart rate during sleep was associated with the strength of excitatory process, the percentage of maximum heart rate index with Conscientiousness, and systolic blood pressure at work was influenced by the strength of inhibitory process. However, generally speaking, physiological indicators of the cardiovascular system functioning were not very sensitive to changes in values of personality and temperament variables at the level of occupational stress reported by the bank clerks who participated in the study.

  5. Stress-associated cardiovascular reaction masks heart rate dependence on physical load in mice.

    Science.gov (United States)

    Andreev-Andrievskiy, A A; Popova, A S; Borovik, A S; Dolgov, O N; Tsvirkun, D V; Custaud, M; Vinogradova, O L

    2014-06-10

    When tested on the treadmill mice do not display a graded increase of heart rate (HR), but rather a sharp shift of cardiovascular indices to high levels at the onset of locomotion. We hypothesized that under test conditions cardiovascular reaction to physical load in mice is masked with stress-associated HR increase. To test this hypothesis we monitored mean arterial pressure (MAP) and heart rate in C57BL/6 mice after exposure to stressful stimuli, during spontaneous locomotion in the open-field test, treadmill running or running in a wheel installed in the home cage. Mice were treated with β1-adrenoblocker atenolol (2mg/kg ip, A), cholinolytic ipratropium bromide (2mg/kg ip, I), combination of blockers (A+I), anxiolytic diazepam (5mg/kg ip, D) or saline (control trials, SAL). MAP and HR in mice increased sharply after handling, despite 3weeks of habituation to the procedure. Under stressful conditions of open field test cardiovascular parameters in mice were elevated and did not depend on movement speed. HR values did not differ in I and SAL groups and were reduced with A or A+I. HR was lower at rest in D pretreated mice. In the treadmill test HR increase over speeds of 6, 12 and 18m/min was roughly 1/7-1/10 of HR increase observed after placing the mice on the treadmill. HR could not be increased with cholinolytic (I), but was reduced after sympatholytic (A) or A+I treatment. Anxiolytic (D) reduced heart rate at lower speeds of movement and its overall effect was to unmask the dependency of HR on running speed. During voluntary running in non-stressful conditions of the home cage HR in mice linearly increased with increasing running speeds. We conclude that in test situations cardiovascular reactions in mice are governed predominantly by stress-associated sympathetic activation, rendering efforts to evaluate HR and MAP reactions to workload unreliable. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Autonomic and inflammatory consequences of posttraumatic stress disorder and the link to cardiovascular disease.

    Science.gov (United States)

    Brudey, Chevelle; Park, Jeanie; Wiaderkiewicz, Jan; Kobayashi, Ihori; Mellman, Thomas A; Marvar, Paul J

    2015-08-15

    Stress- and anxiety-related disorders are on the rise in both military and general populations. Over the next decade, it is predicted that treatment of these conditions, in particular, posttraumatic stress disorder (PTSD), along with its associated long-term comorbidities, will challenge the health care system. Multiple organ systems are adversely affected by PTSD, and PTSD is linked to cancer, arthritis, digestive disease, and cardiovascular disease. Evidence for a strong link between PTSD and cardiovascular disease is compelling, and this review describes current clinical data linking PTSD to cardiovascular disease, via inflammation, autonomic dysfunction, and the renin-angiotensin system. Recent clinical and preclinical evidence regarding the role of the renin-angiotensin system in the extinction of fear memory and relevance in PTSD-related immune and autonomic dysfunction is also addressed. Copyright © 2015 the American Physiological Society.

  7. Work-related stress as a cardiovascular risk factor in police officers: a systematic review of evidence.

    Science.gov (United States)

    Magnavita, N; Capitanelli, I; Garbarino, S; Pira, E

    2018-05-01

    Several studies suggest that work-related stress in police officers may be associated with an increased risk of cardiovascular diseases. A systematic review of studies is, however, still lacking. According to PRISMA statement, a systematic search of PubMed, ISI Web of Science, Cinahl and PsychInfo electronic databases was undertaken. Studies published in English between 1/1/2000 and 31/12/2016 were included. A studies quality assessment was performed using the Newcastle Ottawa scale (NOS). The preliminary search retrieved 752 records. After selection, 16 studies (total population 17,698) were retrieved. The average quality of studies was low. Exposure to stress in cross-sectional studies was inconstantly associated with hypertension, obesity, dyslipidaemia, and impaired glucose metabolism. In addition, there was a prevalence of positive studies showing an association between stress and cardiovascular disease morbidity. Studies of higher quality, such as longitudinal studies on large sample size, were more supportive of a significant positive association between stress and cardiovascular risk factors. Results were, however, often conflicting and inconsistent with regard to definitions and measurement of stress, features of individual study design, study conduct, and conclusions drawn. A sound precautionary principle would be to adopt worksite health promotion programs designed to implement stress management strategies in this category of workers.

  8. Micromagnetic modeling of the effects of stress on magnetic properties

    International Nuclear Information System (INIS)

    Zhu, B.; Lo, C. C. H.; Lee, S. J.; Jiles, D. C.

    2001-01-01

    A micromagnetic model has been developed for investigating the effect of stress on the magnetic properties of thin films. This effect has been implemented by including the magnetoelastic energy term into the Landau - Lifshitz - Gilbert equation. Magnetization curves of a nickel film were calculated under both tensile and compressive stresses of various magnitudes applied along the field direction. The modeling results show that coercivity increased with increasing compressive stress while remanence decreased with increasing tensile stress. The results are in agreement with the experimental data in the literature and can be interpreted in terms of the effects of the applied stress on the irreversible rotation of magnetic moments during magnetization reversal under an applied field. [copyright] 2001 American Institute of Physics

  9. Coping with racism: the impact of prayer on cardiovascular reactivity and post-stress recovery in African American women.

    Science.gov (United States)

    Cooper, Denise C; Thayer, Julian F; Waldstein, Shari R

    2014-04-01

    Prayer is often used to cope with racism-related stress. Little is known about its impact on cardiovascular function. This study examined how prayer coping relates to cardiovascular reactivity (CVR), post-stress recovery, and affective reactivity in response to racism-related stress. African American women (n =81; mean age=20 years) reported their use of prayer coping on the Perceived Racism Scale and completed anger recall and racism recall tasks while undergoing monitoring of systolic and diastolic blood pressure (DBP), heart rate, heart rate variability (HRV), and hemodynamic measures. Prayer coping was examined for associations with CVR, recovery, and affective change scores using general linear models with repeated measures. Higher prayer coping was associated with decreased state stress and DBP reactivity during racism recall (p'sracism recall recovery(p'sracism by utilizing prayer may have cardiovascular benefits for African American women.

  10. Current variables, definitions and endpoints of the European Cardiovascular Magnetic Resonance Registry

    Directory of Open Access Journals (Sweden)

    Schwitter Juerg

    2009-11-01

    Full Text Available Abstract Background Cardiovascular Magnetic Resonance (CMR is increasingly used in daily clinical practice. However, little is known about its clinical utility such as image quality, safety and impact on patient management. In addition, there is limited information about the potential of CMR to acquire prognostic information. Methods The European Cardiovascular Magnetic Resonance Registry (EuroCMR Registry will consist of two parts: 1 Multicenter registry with consecutive enrolment of patients scanned in all participating European CMR centres using web based online case record forms. 2 Prospective clinical follow up of patients with suspected coronary artery disease (CAD and hypertrophic cardiomyopathy (HCM every 12 months after enrolment to assess prognostic data. Conclusion The EuroCMR Registry offers an opportunity to provide information about the clinical utility of routine CMR in a large number of cases and a diverse population. Furthermore it has the potential to gather information about the prognostic value of CMR in specific patient populations.

  11. Role of nucleus of the solitary tract noradrenergic neurons in post-stress cardiovascular and hormonal control in male rats.

    Science.gov (United States)

    Bundzikova-Osacka, Jana; Ghosal, Sriparna; Packard, Benjamin A; Ulrich-Lai, Yvonne M; Herman, James P

    2015-01-01

    Chronic stress causes hypothalamo-pituitary-adrenal (HPA) axis hyperactivity and cardiovascular dyshomeostasis. Noradrenergic (NA) neurons in the nucleus of the solitary tract (NTS) are considered to play a role in these changes. In this study, we tested the hypothesis that NTS NA A2 neurons are required for cardiovascular and HPA axis responses to both acute and chronic stress. Adult male rats received bilateral microinjection into the NTS of 6-hydroxydopamine (6-OHDA) to lesion A2 neurons [cardiovascular study, n = 5; HPA study, n = 5] or vehicle [cardiovascular study, n = 6; HPA study, n = 4]. Rats were exposed to acute restraint stress followed by 14 d of chronic variable stress (CVS). On the last day of testing, rats were placed in a novel elevated plus maze (EPM) to test post-CVS stress responses. Lesions of NTS A2 neurons reduced the tachycardic response to acute restraint, confirming that A2 neurons promote sympathetic activation following acute stress. In addition, CVS increased the ratio of low-frequency to high-frequency power for heart rate variability, indicative of sympathovagal imbalance, and this effect was significantly attenuated by 6-OHDA lesion. Lesions of NTS A2 neurons reduced acute restraint-induced corticosterone secretion, but did not affect the corticosterone response to the EPM, indicating that A2 neurons promote acute HPA axis responses, but are not involved in CVS-mediated HPA axis sensitization. Collectively, these data indicate that A2 neurons promote both cardiovascular and HPA axis responses to acute stress. Moreover, A2 catecholaminergic neurons may contribute to the potentially deleterious enhancement of sympathetic drive following chronic stress.

  12. Cardiovascular and metabolic consequences of the association between chronic stress and high-fat diet in rats.

    Science.gov (United States)

    Simas, Bruna B; Nunes, Everson A; Crestani, Carlos C; Speretta, Guilherme F

    2018-05-01

    Obesity and chronic stress are considered independent risk factors for the development of cardiovascular diseases and changes in autonomic system activity. However, the cardiovascular consequences induced by the association between high-fat diet (HFD) and chronic stress are not fully understood. We hypothesized that the association between HFD and exposure to a chronic variable stress (CVS) protocol for four weeks might exacerbate the cardiovascular and metabolic disturbances in rats when compared to these factors singly. To test this hypothesis, male Wistar rats were divided into four groups: control-standard chow diet (SD; n = 8); control-HFD (n = 8); CVS-SD (n = 8); and CVS-HFD (n = 8). The CVS consisted of repeated exposure of the rats to different inescapable and unpredictable stressors (restraint tress; damp sawdust, cold, swim stress and light cycle inversion). We evaluated cardiovascular function, autonomic activity, dietary intake, adiposity and metabolism. The HFD increased body weight, adiposity and blood glucose concentration (∼15%) in both control and CVS rats. The CVS-HFD rats showed decreased insulin sensitivity (25%) compared to CVS-SD rats. The control-HFD and CVS-HFD rats presented increased intrinsic heart rate (HR) values (∼8%). CVS increased cardiac sympathetic activity (∼65%) in both SD- and HFD-fed rats. The HFD increased basal HR (∼10%). Blood pressure and baroreflex analyzes showed no differences among the experimental groups. In conclusion, the present data indicate absence of interaction on autonomic imbalance evoked by either CVS or HFD. Additionally, HFD increased HR and evoked metabolic disruptions which are independent of stress exposure.

  13. Non-cardiovascular findings in clinical cardiovascular magnetic resonance imaging in children

    International Nuclear Information System (INIS)

    Ghadimi Mahani, Maryam; Morani, Ajaykumar C.; Lu, Jimmy C.; Dorfman, Adam L.; Fazeli Dehkordy, Soudabeh; Jeph, Sunil; Agarwal, Prachi P.

    2016-01-01

    With increasing use of pediatric cardiovascular MRI, it is important for all imagers to become familiar with the spectrum of non-cardiovascular imaging findings that can be encountered. This study aims to ascertain the prevalence and nature of these findings in pediatric cardiovascular MRIs performed at our institution. We retrospectively evaluated reports of all cardiovascular MRI studies performed at our institute from January 2008 to October 2012 in patients younger than18 years. Most studies (98%) were jointly interpreted by a pediatric cardiologist and a radiologist. We reviewed the electronic medical records of all cases with non-cardiovascular findings, defined as any imaging finding outside the cardiovascular system. Non-cardiovascular findings were classified into significant and non-significant, based on whether they were known at the time of imaging or they required additional workup or a change in management. In 849 consecutive studies (mean age 9.7 ± 6.3 years), 145 non-cardiovascular findings were found in 140 studies (16.5% of total studies). Overall, 51.0% (74/145) of non-cardiovascular findings were in the abdomen, 30.3% (44/145) were in the chest, and 18.6% (27/145) were in the spine. A total of 19 significant non-cardiovascular findings were observed in 19 studies in individual patients (2.2% of total studies, 47% male, mean age 5.9 ± 6.7 years). Significant non-cardiovascular findings included hepatic adenoma, arterially enhancing focal liver lesions, asplenia, solitary kidney, pelvicaliectasis, renal cystic diseases, gastric distention, adrenal hemorrhage, lung hypoplasia, air space disease, bronchial narrowing, pneumomediastinum and retained surgical sponge. Non-cardiovascular findings were seen in 16.5% of cardiovascular MRI studies in children, of which 2.2% were clinically significant findings. Prevalence and nature of these non-cardiovascular findings are different from those reported in adults. Attention to these findings is important

  14. Non-cardiovascular findings in clinical cardiovascular magnetic resonance imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Ghadimi Mahani, Maryam [University of Michigan Health System, C.S. Mott Children' s Hospital, Department of Radiology, Section of Pediatric Radiology, Ann Arbor, MI (United States); Morani, Ajaykumar C. [The University of Texas MD Anderson Cancer Center, Department of Diagnostic Radiology, Houston, TX (United States); Lu, Jimmy C.; Dorfman, Adam L. [University of Michigan Health System, C.S. Mott Children' s Hospital, Department of Pediatrics and Communicable Diseases, Division of Pediatric Cardiology, Ann Arbor, MI (United States); Fazeli Dehkordy, Soudabeh [University of Michigan Health System, C.S. Mott Children' s Hospital, Department of Radiology, Section of Pediatric Radiology, Ann Arbor, MI (United States); Providence Hospital and Medical Centers, Department of Graduate Medical Education, Southfield, MI (United States); Jeph, Sunil [The University of Texas MD Anderson Cancer Center, Department of Diagnostic Radiology, Houston, TX (United States); Geisinger Medical Center, Department of Radiology, Danville, PA (United States); Agarwal, Prachi P. [University of Michigan Health System, Department of Radiology, Division of Cardiothoracic Radiology, Ann Arbor, MI (United States)

    2016-04-15

    With increasing use of pediatric cardiovascular MRI, it is important for all imagers to become familiar with the spectrum of non-cardiovascular imaging findings that can be encountered. This study aims to ascertain the prevalence and nature of these findings in pediatric cardiovascular MRIs performed at our institution. We retrospectively evaluated reports of all cardiovascular MRI studies performed at our institute from January 2008 to October 2012 in patients younger than18 years. Most studies (98%) were jointly interpreted by a pediatric cardiologist and a radiologist. We reviewed the electronic medical records of all cases with non-cardiovascular findings, defined as any imaging finding outside the cardiovascular system. Non-cardiovascular findings were classified into significant and non-significant, based on whether they were known at the time of imaging or they required additional workup or a change in management. In 849 consecutive studies (mean age 9.7 ± 6.3 years), 145 non-cardiovascular findings were found in 140 studies (16.5% of total studies). Overall, 51.0% (74/145) of non-cardiovascular findings were in the abdomen, 30.3% (44/145) were in the chest, and 18.6% (27/145) were in the spine. A total of 19 significant non-cardiovascular findings were observed in 19 studies in individual patients (2.2% of total studies, 47% male, mean age 5.9 ± 6.7 years). Significant non-cardiovascular findings included hepatic adenoma, arterially enhancing focal liver lesions, asplenia, solitary kidney, pelvicaliectasis, renal cystic diseases, gastric distention, adrenal hemorrhage, lung hypoplasia, air space disease, bronchial narrowing, pneumomediastinum and retained surgical sponge. Non-cardiovascular findings were seen in 16.5% of cardiovascular MRI studies in children, of which 2.2% were clinically significant findings. Prevalence and nature of these non-cardiovascular findings are different from those reported in adults. Attention to these findings is important

  15. Cardiovascular magnetic resonance in hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Shiozaki, Afonso Akio; Parga, Jose Rodrigues; Arteaga, Edmundo; Rochitte, Carlos Eduardo; Tassi, Eduardo Marinho

    2007-01-01

    Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiac disease that causes sudden death in young people, with an incidence of 1:500 adults. The routinely used criteria for worst prognosis have limited sensitivity and specificity. Thus, the estimated risk of evolving to dilated cardiomyopathy or sudden death is somewhat inaccurate, leading to management uncertainty of HCM patients. Therefore, an accurate noninvasive method for the diagnosis of HCM with prognostic value is of great importance. In the last years, Cardiovascular Magnetic Resonance (CMR) emerged not only as a diagnostic tool, but also as a study with prognostic values, by characterizing myocardial fibrosis with great accuracy in HCM patients. Additionally, CMR identifies the types of hypertrophy, analyses the ventricular function, estimates the intraventricular gradient and allows the determination of differential diagnosis. Moreover, CMR can uniquely access myocardial fibrosis in HCM. (author)

  16. Wall shear stress fixed points in cardiovascular fluid mechanics.

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn C

    2018-05-17

    Complex blood flow in large arteries creates rich wall shear stress (WSS) vectorial features. WSS acts as a link between blood flow dynamics and the biology of various cardiovascular diseases. WSS has been of great interest in a wide range of studies and has been the most popular measure to correlate blood flow to cardiovascular disease. Recent studies have emphasized different vectorial features of WSS. However, fixed points in the WSS vector field have not received much attention. A WSS fixed point is a point on the vessel wall where the WSS vector vanishes. In this article, WSS fixed points are classified and the aspects by which they could influence cardiovascular disease are reviewed. First, the connection between WSS fixed points and the flow topology away from the vessel wall is discussed. Second, the potential role of time-averaged WSS fixed points in biochemical mass transport is demonstrated using the recent concept of Lagrangian WSS structures. Finally, simple measures are proposed to quantify the exposure of the endothelial cells to WSS fixed points. Examples from various arterial flow applications are demonstrated. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Simulation of stress-modulated magnetization precession frequency in Heusler-based spin torque oscillator

    International Nuclear Information System (INIS)

    Huang, Houbing; Zhao, Congpeng; Ma, Xingqiao

    2017-01-01

    We investigated stress-modulated magnetization precession frequency in Heusler-based spin transfer torque oscillator by combining micromagnetic simulations with phase field microelasticity theory, by encapsulating the magnetic tunnel junction into multilayers structures. We proposed a novel method of using an external stress to control the magnetization precession in spin torque oscillator instead of an external magnetic field. The stress-modulated magnetization precession frequency can be linearly modulated by externally applied uniaxial in-plane stress, with a tunable range 4.4–7.0 GHz under the stress of 10 MPa. By comparison, the out-of-plane stress imposes negligible influence on the precession frequency due to the large out-of-plane demagnetization field. The results offer new inspiration to the design of spin torque oscillator devices that simultaneously process high frequency, narrow output band, and tunable over a wide range of frequencies via external stress. - Highlights: • We proposed stress-modulated magnetization precession in spin torque oscillator. • The magnetization precession frequency can be linearly modulated by in-plane stress. • The stress also can widen the magnetization frequency range 4.4–7.0 GHz. • The stress-modulated oscillation frequency can simplify STO devices.

  18. Simulation of stress-modulated magnetization precession frequency in Heusler-based spin torque oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Houbing, E-mail: hbhuang@ustb.edu.cn; Zhao, Congpeng; Ma, Xingqiao, E-mail: xqma@sas.ustb.edu.cn

    2017-03-15

    We investigated stress-modulated magnetization precession frequency in Heusler-based spin transfer torque oscillator by combining micromagnetic simulations with phase field microelasticity theory, by encapsulating the magnetic tunnel junction into multilayers structures. We proposed a novel method of using an external stress to control the magnetization precession in spin torque oscillator instead of an external magnetic field. The stress-modulated magnetization precession frequency can be linearly modulated by externally applied uniaxial in-plane stress, with a tunable range 4.4–7.0 GHz under the stress of 10 MPa. By comparison, the out-of-plane stress imposes negligible influence on the precession frequency due to the large out-of-plane demagnetization field. The results offer new inspiration to the design of spin torque oscillator devices that simultaneously process high frequency, narrow output band, and tunable over a wide range of frequencies via external stress. - Highlights: • We proposed stress-modulated magnetization precession in spin torque oscillator. • The magnetization precession frequency can be linearly modulated by in-plane stress. • The stress also can widen the magnetization frequency range 4.4–7.0 GHz. • The stress-modulated oscillation frequency can simplify STO devices.

  19. Evaluating the Impact of a Brief Artistic Intervention on Cardiovascular Recovery from Acute Stress

    Science.gov (United States)

    Keogh, Katharina; Creaven, Ann-Marie

    2017-01-01

    In this study we tested whether drawing and coloring influence cardiovascular recovery and perceived stress following exposure to a stressor. In a mixed experimental design, participants (N = 62) completed an acute stress task before being randomly assigned to one of three brief activities: free-form drawing (full creative control), coloring…

  20. Cardiovascular Disease Risk Factors in Patients with Posttraumatic Stress Disorder (PTSD): A Narrative Review.

    Science.gov (United States)

    Šagud, Marina; Jakšić, Nenad; Vuksan-Ćusa, Bjanka; Lončar, Mladen; Lončar, Ivana; Peleš, Alma Mihaljević; Miličić, Davor; Jakovljević, Miro

    2017-12-01

    Posttraumatic stress disorder (PTSD) is a chronic condition related to severe stress and trauma. There is a mounting evidence about increased prevalence and mortality from cardiovascular diseases (CVD) in patients with PTSD. This review summarizes the current data on possible relations between PTSD and increased risks of CVD, including biological, psychological and behavioral factors. Biological factors refer to increased prevalence of metabolic syndrome (MetS), hypertension, elevation of pro-inflammatory cytokines and homocysteine levels. Peripheral Brain-derived neurotropic factor (BDNF), serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and quantitative electroencephalogram (qEEG) are promising surrogate markers of increased cardiovascular risk. Among psychological factors, some personality traits, such as neuroticism and trait impulsivity/hostility, contribute to the development of PTSD, and are associated with general cardiovascular distress. Recently, type-D (distressed) personality is usually investigated in relation to cardiovascular morbidity, but in populations other than PTSD patients. Behavioral factors refer to unhealthy life-styles, encompassing high smoking rate, drug substances abuse and addiction, physical inactivity and unhealthy diet. The relationships among all these factors are complex and yet incompletely taken into consideration. Because of a high prevalence of CVD in patients with PTSD, there is a strong need for a more intensive focus on this vulnerable population in both primary and secondary cardiovascular prevention as well as in effective treatment possibilities.

  1. Investigation on stresses of superconductors under pulsed magnetic fields based on multiphysics model

    International Nuclear Information System (INIS)

    Yang, Xiaobin; Li, Xiuhong; He, Yafeng; Wang, Xiaojun; Xu, Bo

    2017-01-01

    Highlights: • The differential equation including temperature and magnetic field was derived for a long cylindrical superconductor. • Thermal stress and electromagnetic stress were studied at the same time under pulse field magnetizing. • The distributions of the magnetic field, the temperature and stresses are studied and compared for two pulse fields of the different duration. • The Role thermal stress and electromagnetic stress play in the process of pulse field magnetizing is discussed. - Abstract: A multiphysics model for the numerical computation of stresses, trapped field and temperature distribution of a infinite long superconducting cylinder is proposed, based on which the stresses, including the thermal stresses and mechanical stresses due to Lorentz force, and trapped fields in the superconductor subjected to pulsed magnetic fields are analyzed. By comparing the results under pulsed magnetic fields with different pulse durations, it is found that the both the mechanical stress due to the electromagnetic force and the thermal stress due to temperature gradient contribute to the total stress level in the superconductor. For pulsed magnetic field with short durations, the thermal stress is the dominant contribution to the total stress, because the heat generated by AC-loss builds up significant temperature gradient in such short durations. However, for a pulsed field with a long duration the gradient of temperature and flux, as well as the maximal tensile stress, are much smaller. And the results of this paper is meaningful for the design and manufacture of superconducting permanent magnets.

  2. Investigation on stresses of superconductors under pulsed magnetic fields based on multiphysics model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaobin, E-mail: yangxb@lzu.edu.cn; Li, Xiuhong; He, Yafeng; Wang, Xiaojun; Xu, Bo

    2017-04-15

    Highlights: • The differential equation including temperature and magnetic field was derived for a long cylindrical superconductor. • Thermal stress and electromagnetic stress were studied at the same time under pulse field magnetizing. • The distributions of the magnetic field, the temperature and stresses are studied and compared for two pulse fields of the different duration. • The Role thermal stress and electromagnetic stress play in the process of pulse field magnetizing is discussed. - Abstract: A multiphysics model for the numerical computation of stresses, trapped field and temperature distribution of a infinite long superconducting cylinder is proposed, based on which the stresses, including the thermal stresses and mechanical stresses due to Lorentz force, and trapped fields in the superconductor subjected to pulsed magnetic fields are analyzed. By comparing the results under pulsed magnetic fields with different pulse durations, it is found that the both the mechanical stress due to the electromagnetic force and the thermal stress due to temperature gradient contribute to the total stress level in the superconductor. For pulsed magnetic field with short durations, the thermal stress is the dominant contribution to the total stress, because the heat generated by AC-loss builds up significant temperature gradient in such short durations. However, for a pulsed field with a long duration the gradient of temperature and flux, as well as the maximal tensile stress, are much smaller. And the results of this paper is meaningful for the design and manufacture of superconducting permanent magnets.

  3. Measurements of Pulmonary Artery Size for Assessment of Pulmonary Hypertension by Cardiovascular Magnetic Resonance and Clinical Application

    Directory of Open Access Journals (Sweden)

    Fan YANG

    2017-02-01

    Full Text Available Background and objective Pulmonary hypertension (PH often leads to dilatation of main pulmonary artery (MPA. MPA measurements can be used to predict PH. This aim of this study is to investigate power of MPA vessel indices, which are acquired from cardiovascular magnetic resonance, to evaluate PH. Methods Cardiovascular-magnetic-resonance-determined parameters of MPA were acquired and calculated in 83 PH patients, whose diagnosis were confirmed with right heart catheterization and 49 healthy volunteers; these parameters included MPA diameter (DPA, ratio of DPA and ascending aorta diameter (DPA/DAo, max mean diameter (MDmax, min mean diameter (MDmin, fraction transverse diameter (fTD, fraction longitudinal diameter (fLD, and distensibility. Results Compared with control group, DPA, DPA/DAo, MDmax, and MDmin were significantly higher in patients with PH (P28.4 mm, and MDmax>32.4 mm (area under the curve, AUC=0.979, 0.981 showed best performance in predicting PH, yielding highest specificity at 100%. Conclusion Noninvasive cardiovascular-magnetic-resonance-derived MPA measurements provide excellent and practical reference in clinical settings for detecting PH.

  4. Manipulating the magnetic anisotropy and magnetization dynamics by stress: Numerical calculation and experiment

    Science.gov (United States)

    Correa, M. A.; Bohn, F.

    2018-05-01

    We perform a theoretical and experimental investigation of the magnetic properties and magnetization dynamics of a ferromagnetic magnetostrictive multilayer grown onto a flexible substrate and submitted to external stress. We calculate the magnetic behavior and magnetoimpedance effect for a trilayered system from an approach that considers a magnetic permeability model for planar geometry and a magnetic free energy density which takes into account induced uniaxial and magnetoelastic anisotropy contributions. We verify remarkable modifications of the magnetic anisotropy with external stress, as well as we show that the dynamic magnetic response is strongly affected by these changes. We discuss the magnetic features that lead to modifications of the frequency limits where distinct mechanisms are responsible by the magnetoimpedance variations, enabling us to manipulate the resonance fields. To test the robustness of the approach, we directly compare theoretical results with experimental data. Thus, we provide experimental evidence to confirm the validity of the theoretical approach, as well as to manipulate the resonance fields to tune the MI response according to real applications in devices.

  5. Cardiovascular assessment of patients with Ullrich-Turner's Syndrome on Doppler echocardiography and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Castro Ana Valéria Barros de

    2002-01-01

    Full Text Available OBJECTIVE: To assess the cardiovascular features of Ullrich-Turner's syndrome using echocardiography and magnetic resonance imaging, and to correlate them with the phenotype and karyotype of the patients. The diagnostic concordance between the 2 methods was also assessed. METHODS: Fifteen patients with the syndrome were assessed by echocardiography and magnetic resonance imaging (cardiac chambers, valves, and aorta. Their ages ranged from 10 to 28 (mean of 16.7 years. The karyotype was analyzed in 11 or 25 metaphases of peripheral blood lymphocytes, or both. RESULTS: The most common phenotypic changes were short stature and spontaneous absence of puberal development (100%; 1 patient had a cardiac murmur. The karyotypes detected were as follows: 45,X (n=7, mosaics (n=5, and deletions (n=3. No echocardiographic changes were observed. In regard to magnetic resonance imaging, coarctation and dilation of the aorta were found in 1 patient, and isolated dilation of the aorta was found in 4 patients. CONCLUSION: The frequencies of coarctation and dilation of the aorta detected on magnetic resonance imaging were similar to those reported in the literature (5.5% to 20%, and 6.3% to 29%, respectively. This confirmed the adjuvant role of magnetic resonance imaging to Doppler echocardiography for diagnosing cardiovascular alterations in patients with Ullrich-Turner's syndrome.

  6. Usefulness of Myocardial Annular Velocity Change During Mental Stress to Predict Cardiovascular Outcome in Patients With Coronary Artery Disease (From the Responses of Mental Stress-Induced Myocardial Ischemia to Escitalopram Treatment Trial).

    Science.gov (United States)

    Alenezi, Fawaz; Brummett, Beverly H; Boyle, Stephen H; Samad, Zainab; Babyak, Michael A; Alzaeim, Nabil; Wilson, Jennifer; Romano, Minna M D; Sun, Julia L; Ersboll, Mads; O'Connor, Christopher M; Velazquez, Eric J; Jiang, Wei

    2017-11-01

    Mental stress-induced myocardial ischemia is common and a prognostic factor of adverse cardiovascular outcomes in patients with coronary artery disease (CAD). The present study aimed at examining associations between mental stress-induced myocardial annular velocity (MAV) and cardiovascular outcome in patients with CAD. MAV, specifically, diastolic early (e'), diastolic late (a'), and systolic (s') velocities were obtained at rest and during mental stress testing in 224 patients with clinically stable CAD. Using Cox regression models, age, sex, and baseline-adjusted mental stress-induced MAV measures were examined as predictors of a priori defined composite event term that comprised all-cause mortality and/or nonfatal cardiovascular events, resulting in an unplanned hospitalization (major adverse cardiovascular events [MACE]). Median follow-up was 4 years. The sample was predominantly male, Caucasian with New York Heart Association functional class I and a mean age of 63 ± 10.2 years. MS-induced changes in e' (hazard ratio [HR] = .73) and s' (HR = .73) were significant (p Mental stress-induced MAV changes independently predict an adverse cardiovascular outcome in patients with stable CAD. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Magnetostriction of a sphere: stress development during magnetization and residual stresses due to the remanent field

    Science.gov (United States)

    Reich, Felix A.; Rickert, Wilhelm; Stahn, Oliver; Müller, Wolfgang H.

    2017-03-01

    Based on the principles of rational continuum mechanics and electrodynamics (see Truesdell and Toupin in Handbuch der Physik, Springer, Berlin, 1960 or Kovetz in Electromagnetic theory, Oxford University Press, Oxford, 2000), we present closed-form solutions for the mechanical displacements and stresses of two different magnets. Both magnets are initially of spherical shape. The first (hard) magnet is uniformly magnetized and deforms due to the field induced by the magnetization. In the second problem of a (soft) linear-magnetic sphere, the deformation is caused by an applied external field, giving rise to magnetization. Both problems can be used for modeling parts of general magnetization processes. We will address the similarities between both settings in context with the solutions for the stresses and displacements. In both problems, the volumetric Lorentz force density vanishes. However, a Lorentz surface traction is present. This traction is determined from the magnetic flux density. Since the obtained displacements and stresses are small in magnitude, we may use Hooke's law with a small-strain approximation, resulting in the Lamé- Navier equations of linear elasticity theory. If gravity is neglected and azimuthal symmetry is assumed, these equations can be solved in terms of a series. This has been done by Hiramatsu and Oka (Int J Rock Mech Min Sci Geomech Abstr 3(2):89-90, 1966) before. We make use of their series solution for the displacements and the stresses and expand the Lorentz tractions of the analyzed problems suitably in order to find the expansion coefficients. The resulting algebraic system yields finite numbers of nonvanishing coefficients. Finally, the resulting stresses, displacements, principal strains and the Lorentz tractions are illustrated and discussed.

  8. Resveratrol Prevents Cardiovascular Complications in the SHR/STZ Rat by Reductions in Oxidative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Rebecca K. Vella

    2015-01-01

    Full Text Available The cardioprotective effects of resveratrol are well established in animal models of metabolic disease but are yet to be investigated in a combined model of hypertension and diabetes. This study investigated the ability of resveratrol’s antioxidant and anti-inflammatory effects to prevent cardiovascular complications in the spontaneously hypertensive streptozotocin-induced diabetic rat. Diabetes was induced in eight-week-old male spontaneously hypertensive rats via a single intravenous injection of streptozotocin. Following this, resveratrol was administered orally for an eight-week period until the animals were sixteen weeks of age. Upon completion of the treatment regime assessments of oxidative stress, lipid peroxidation, inflammation, and cardiovascular function were made. Resveratrol administration to hypertensive-diabetic animals did not impact upon blood glucose or haemodynamics but significantly reduced oxidative stress, lipid peroxidation, and inflammatory cytokines. Reductions in systemic levels of oxidative stress and inflammation conferred improvements in vascular reactivity and left ventricular pump function and electrophysiology. This study demonstrates that resveratrol administration to hypertensive diabetic animals can elicit cardioprotective properties via antioxidant and anti-inflammatory effects. The observed preservation of cardiovascular function was independent of changes in blood glucose concentration and haemodynamics, suggesting that oxidative stress and inflammation are key components within the pathological cascade associated with hypertension and diabetes.

  9. Job stress and cardiovascular disease: a theoretic critical review.

    Science.gov (United States)

    Kristensen, T S

    1996-07-01

    During the last 15 years, the research on job stress and cardiovascular diseases has been dominated by the job strain model developed by R. Karasek (1979) and colleagues (R. Karasek & T. Theorell, 1990). In this article the results of this research are briefly summarized, and the theoretical and methodological basis is discussed and criticized. A sociological interpretation of the model emphasizing theories of technological change, qualifications of the workers, and the organization of work is proposed. Furthermore, improvements with regard to measuring the job strain dimensions and to sampling the study base are suggested. Substantial improvements of the job strain research could be achieved if the principle of triangulation were used in the measurements of stressors, stress, and sickness and if occupation-based samples were used instead of large representative samples.

  10. Value of Cardiovascular Magnetic Resonance Imaging in Noninvasive Risk Stratification in Tetralogy of Fallot

    NARCIS (Netherlands)

    Bokma, Jouke P.; de Wilde, Koen C.; Vliegen, Hubert W.; van Dijk, Arie P.; van Melle, Joost P.; Meijboom, Folkert J.; Zwinderman, Aeilko H.; Groenink, Maarten; Mulder, Barbara J. M.; Bouma, Berto J.

    IMPORTANCE Adults late after total correction of tetralogy of Fallot (TOF) are at risk for majorcomplications. Cardiovascular magnetic resonance (CMR) imaging is recommended toquantify right ventricular (RV) and left ventricular (LV) function. However, a commonly usedrisk model by Khairy et al

  11. Cardiovascular magnetic resonance in pulmonary hypertension

    Science.gov (United States)

    2012-01-01

    Pulmonary hypertension represents a group of conditions characterized by higher than normal pulmonary artery pressures. Despite improved treatments, outcomes in many instances remain poor. In recent years, there has been growing interest in the use of Cardiovascular Magnetic Resonance (CMR) in patients with pulmonary hypertension. This technique offers certain advantages over other imaging modalities since it is well suited to the assessment of the right ventricle and the proximal pulmonary arteries. Reflecting the relatively sparse evidence supporting its use, CMR is not routinely recommended for patients with pulmonary hypertension. However, it is particularly useful in patient with pulmonary arterial hypertension associated with congenital heart disease. Furthermore, it has proven informative in a number of ways; illustrating how right ventricular remodeling is favorably reversed by drug therapies and providing explicit confirmation of the importance of the right ventricle to clinical outcome. This review will discuss these aspects and practical considerations before speculating on future applications. PMID:22257586

  12. Blockade of central vasopressin receptors reduces the cardiovascular response to acute stress in freely moving rats.

    Science.gov (United States)

    Stojicić, S; Milutinović-Smiljanić, S; Sarenac, O; Milosavljević, S; Paton, J F R; Murphy, D; Japundzić-Zigon, N

    2008-04-01

    To investigate the contribution of central vasopressin receptors to blood pressure (BP) and heart rate (HR) response to stress we injected non-peptide selective V(1a) (SR49059), V(1b) (SSR149415), V(2) (SR121463) receptor antagonists, diazepam or vehicle in the lateral cerebral ventricle of conscious freely moving rats stressed by blowing air on their heads for 2 min. Cardiovascular effects of stress were evaluated by analyzing maximum increase of BP and HR (MAX), latency of maximum response (LAT), integral under BP and HR curve (integral), duration of their recovery and spectral parameters of BP and HR indicative of increased sympathetic outflow (LF(BP) and LF/HF(HR)). Moreover, the increase of serum corticosterone was measured. Exposure to air-jet stress induced simultaneous increase in BP and HR followed by gradual decline during recovery while LF(BP) oscillation remained increased as well as serum corticosterone level. Rats pre-treated with vasopressin receptor antagonists were not sedated while diazepam induced sedation that persisted during exposure to stress. V(1a), V(1b) and V(2) receptor antagonists applied separately did not modify basal values of cardiovascular parameters but prevented the increase in integral(BP). In addition, V(1b) and V(2) receptor antagonists reduced BP(MAX) whereas V(1a), V(1b) antagonist and diazepam reduced HR(MAX) induced by exposure to air-jet stress. All drugs shortened the recovery period, prevented the increase of LF(BP) without affecting the increase in serum corticosterone levels. Results indicate that vasopressin receptors located within the central nervous system mediate, in part, the cardiovascular response to air-jet stress without affecting either the neuroendocrine component or inducing sedation. They support the view that the V(1b) receptor antagonist may be of potential therapeutic value in reducing arterial pressure induced by stress-related disorders.

  13. Stress analysis in high-temperature superconductors under pulsed field magnetization

    Science.gov (United States)

    Wu, Haowei; Yong, Huadong; Zhou, Youhe

    2018-04-01

    Bulk high-temperature superconductors (HTSs) have a high critical current density and can trap a large magnetic field. When bulk superconductors are magnetized by the pulsed field magnetization (PFM) technique, they are also subjected to a large electromagnetic stress, and the resulting thermal stress may cause cracking of the superconductor due to the brittle nature of the sample. In this paper, based on the H-formulation and the law of heat transfer, we can obtain the distributions of electromagnetic field and temperature, which are in qualitative agreement with experiment. After that, based on the dynamic equilibrium equations, the mechanical response of the bulk superconductor is determined. During the PFM process, the change in temperature has a dramatic effect on the radial and hoop stresses, and the maximum radial and hoop stress are 24.2 {{MPa}} and 22.6 {{MPa}}, respectively. The mechanical responses of a superconductor for different cases are also studied, such as the peak value of the applied field and the size of bulk superconductors. Finally, the stresses are also presented for different magnetization methods.

  14. Influence of Acute Multispecies and Multistrain Probiotic Supplementation on Cardiovascular Function and Reactivity to Psychological Stress in Young Adults: A Double-Blind, Randomized, Placebo-Controlled Trial.

    Science.gov (United States)

    Möller, Clara M; Olsa, Eamon J A; Ginty, Annie T; Rapelje, Alyssa L; Tindall, Christina L; Holesh, Laura A; Petersen, Karen L; Conklin, Sarah M

    2017-10-01

    The potential influence of probiotic supplementation on cardiovascular health and stress responsivity remains largely unexplored. Some evidence suggests the possibility that probiotics may influence blood pressure. A separate body of research suggests that exaggerated cardiovascular reactions to acute psychological stress in the laboratory predict cardiovascular morbidity and mortality. The current investigation explored the effect of acute probiotic use on (1) resting cardiovascular measures in healthy young adults and (2) cardiovascular and psychological reactions to an acute psychological stressor in the laboratory. Participants (N = 105, M [SD] age = 20.17 [1.26], 84.8% white) completed a 2-week, double-blind, and placebo-controlled trial of a multispecies and multistrain probiotic. Exclusion criteria included previous probiotic use, diagnosed gastrointestinal disorder, and/or current antibiotic use. At visits 1 and 2, participants completed the Paced Auditory Serial Addition Test, a widely used psychological stress task. Participants were randomly assigned to a probiotic blend or matched placebo. Compared with placebo, 2-week probiotic supplementation did not affect resting measures of cardiovascular function, cardiovascular responses during or recovery from stress, or psychological reactions to acute psychological stress. Contrary to expectations, short-term use of a probiotic supplement in healthy participants did not influence measures of cardiovascular function or responsivity to psychological stress. Future research is needed to determine species- and strain-specific effects of probiotics in healthy participants with various degrees of stress responsiveness, as well as in diseased populations.

  15. Stress state evaluation in low carbon and TRIP steels by magnetic permeability

    International Nuclear Information System (INIS)

    Kouli, M.-E.; Giannakis, M

    2016-01-01

    Magnetic permeability is an indicative factor for the steel health monitoring. The measurements of magnetic permeability lead to the evaluation of the stress state of any ferromagnetic steel. The magnetic permeability measurements were conducted on low carbon and TRIP steel samples, which were subjected to both tensile and compressive stresses. The results indicated a direct correlation of the magnetic permeability with the mechanical properties, the stress state and the microstructural features of the examined samples. (paper)

  16. Cardiovascular nuclear medicine and MRI

    International Nuclear Information System (INIS)

    Reiber, J.H.C.; Wall, E.E. van der

    1992-01-01

    This book is based on a meeting of the Working Group on Nuclear Cardiology, which held March 22-23,1991 under the auspices of the European Society of Cardiology and the Interuniversity Cardiology Institute of the Netherlands, and on the Second International Symposium on Computer Applications in Nuclear Medicine and Cardiac Magnetic Resonance Imaging, which was held March 20-22,1991 in Rotterdam, the Netherlands. It covers almost every aspect of quantitative cardio-vascular nuclear medicine and magnetic resonance imaging. The main topics are: single photon emission computed tomography (technical aspects); new development in cardiovascular nuclear medicine; advances in cardiovascular imaging; cardiovascular clinical applications; and cardiac magnetic resonance imaging. (A.S.). refs.; figs.; tabs

  17. Sociotropic cognition moderates stress-induced cardiovascular responsiveness in college women.

    Science.gov (United States)

    Sauro, M D; Jorgensen, R S; Larson, C A; Frankowski, J J; Ewart, C K; White, J

    2001-10-01

    This study examined the moderating effects of sociotropic cognition (SC), a nondefensive need for approval, on stress-induced cardiovascular responsiveness (CVR) in women. Sixty-seven college-age females had blood pressure (BP) and heart rate (HR) monitored during baseline, anticipation, story-telling (where participants were randomly assigned to a low or high threat condition), and recovery periods. SC showed a positive association with CVR only in the high interpersonal threat context during task and early stages of the recovery periods. SC was positively correlated with such variables as anxiety, ruminative style, dysphoria, and anger. This is the first report examining the moderating effects of SC on interpersonal stress-induced CVR prior to, during, and following a task, using an explicit manipulation of social evaluation. The data help define risk factors for CVR in women, which may aid in the understanding of how emotions and stress affect physical health and well-being.

  18. Effect of Mechanical Stresses and Annealing on the Magnetic Structure and the Magnetic Impedance of Amorphous CoFeSiBCr Microwires

    Science.gov (United States)

    Nematov, M. G.; Salem, M. M.; Azim, U.; Akhmat, M.; Morchenko, A. T.; Yudanov, N. A.; Panina, L. V.

    2018-02-01

    The structural and magnetic properties of amorphous ferromagnetic microwires can undergo significant measurements under the action of external mechanical stresses and heat treatment. The study of transformations occurring in this case is important for designing various sensors of mechanical stresses, loading, and temperature and also for inducing in the wires a certain type of magnetic anisotropy that plays a significant role in the realization of various effects in them. In this work, the influence of external stresses and annealing on the processes of the magnetization and the magnetic impedance of Co71Fe5B11Si10Cr3 microwires having a low positive magnetostriction ( 10-8) in amorphous state has been studied. The influence of external stresses leads to a sharp change in the character of the magnetization reversal curve, which was due to the change in the sign of the magnetostriction and the type of magnetic anisotropy. The amplitude of higher harmonics and the value of the magnetic impedance, respectively, are sensitive to mechanical stresses. Elastic stresses in the wires with a partial crystallization do not lead to a marked change in the magnetic properties; however, annealing can lead to a substantial increase in the axial magnetic anisotropy of the wires existing in the stressed state. The experimental results are analyzed in the framework of a magnetostriction model of induced magnetic anisotropy.

  19. Uncomplicated obesity is associated with abnormal aortic function assessed by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Channon Keith M

    2008-02-01

    Full Text Available Abstract Aims Obese subjects with insulin resistance and hypertension have abnormal aortic elastic function, which may predispose them to the development of left ventricular dysfunction. We hypothesised that obesity, uncomplicated by other cardiovascular risk factors, is independently associated with aortic function. Methods and results We used magnetic resonance imaging to measure aortic compliance, distensibility and stiffness index in 27 obese subjects (BMI 33 kg/m2 without insulin resistance and with normal cholesterol and blood pressure, and 12 controls (BMI 23 kg/m2. Obesity was associated with reduced aortic compliance (0.9 ± 0.1 vs. 1.5 ± 0.2 mm2/mmHg in controls, p -1 × 10-3, p Conclusion Aortic elastic function is abnormal in obese subjects without other cardiovascular risk factors. These findings highlight the independent importance of obesity in the development of cardiovascular disease.

  20. Pulmonary oxidative stress, inflammation and dysregulated iron homeostatis in rat models of cardiovascular disease

    Science.gov (United States)

    Underlying cardiovascular disease (CVD) is considered a risk factor for the exacerbation of air pollution health effects. Therefore, rodent models of CVD are increasingly used to examine mechanisms ofvariation in susceptibility. Pulmonary oxidative stress, inflammation and altere...

  1. Standardized cardiovascular magnetic resonance imaging (CMR protocols, society for cardiovascular magnetic resonance: board of trustees task force on standardized protocols

    Directory of Open Access Journals (Sweden)

    Kim Raymond J

    2008-07-01

    Full Text Available Index 1. General techniques 1.1. Stress and safety equipment 1.2. Left ventricular (LV structure and function module 1.3. Right ventricular (RV structure and function module 1.4. Gadolinium dosing module. 1.5. First pass perfusion 1.6. Late gadolinium enhancement (LGE 2. Disease specific protocols 2.1. Ischemic heart disease 2.1.1. Acute myocardial infarction (MI 2.1.2. Chronic ischemic heart disease and viability 2.1.3. Dobutamine stress 2.1.4. Adenosine stress perfusion 2.2. Angiography: 2.2.1. Peripheral magnetic resonance angiography (MRA 2.2.2. Thoracic MRA 2.2.3. Anomalous coronary arteries 2.2.4. Pulmonary vein evaluation 2.3. Other 2.3.1. Non-ischemic cardiomyopathy 2.3.2. Arrhythmogenic right ventricular cardiomyopathy (ARVC 2.3.3. Congenital heart disease 2.3.4. Valvular heart disease 2.3.5. Pericardial disease 2.3.6. Masses

  2. Roles of oxidative stress, adiponectin, and nuclear hormone receptors in obesity-associated insulin resistance and cardiovascular risk.

    Science.gov (United States)

    Matsuda, Morihiro; Shimomura, Iichiro

    2014-08-01

    Obesity leads to the development of type 2 diabetes mellitus, which is a strong risk factor for cardiovascular disease. A better understanding of the molecular basis of obesity will lead to the establishment of effective prevention strategies for cardiovascular diseases. Adipocytes have been shown to generate a variety of endocrine factors termed adipokines/adipocytokines. Obesity-associated changes to these adipocytokines contribute to the development of cardiovascular diseases. Adiponectin, which is one of the most well-characterized adipocytokines, is produced exclusively by adipocytes and exerts insulin-sensitizing and anti-atherogenic effects. Obese subjects have lower levels of circulating adiponectin, and this is recognized as one of the factors involved in obesity-induced insulin resistance and atherosclerosis. Another pathophysiological feature of obesity may involve the low-grade chronic inflammation in adipose tissue. This inflammatory process increases oxidative stress in adipose tissue, which may affect remote organs, leading to the development of diabetes, hypertension, and atherosclerosis. Nuclear hormone receptors (NRs) regulate the transcription of the target genes in response to binding with their ligands, which include metabolic and nutritional substrates. Among the various NRs, peroxisome proliferator-activated receptor γ promotes the transcription of adiponectin and antioxidative enzymes, whereas mineralocorticoid receptor mediates the effects of aldosterone and glucocorticoid to induce oxidative stress in adipocytes. It is hypothesized that both play crucial roles in the pathophysiology of obesity-associated insulin resistance and cardiovascular diseases. Thus, reduced adiponectin and increased oxidative stress play pathological roles in obesity-associated insulin resistance to increase the cardiovascular disease risk, and various NRs may be involved in this pathogenesis.

  3. Cardiovascular mortality and exposure to extremely low frequency magnetic fields: a cohort study of Swiss railway workers

    Directory of Open Access Journals (Sweden)

    Pfluger Dominik

    2008-07-01

    Full Text Available Abstract Background Exposure to intermittent magnetic fields of 16 Hz has been shown to reduce heart rate variability, and decreased heart rate variability predicts cardiovascular mortality. We examined mortality from cardiovascular causes in railway workers exposed to varying degrees to intermittent 16.7 Hz magnetic fields. Methods We studied a cohort of 20,141 Swiss railway employees between 1972 and 2002, including highly exposed train drivers (median lifetime exposure 120.5 μT-years, and less or little exposed shunting yard engineers (42.1 μT-years, train attendants (13.3 μT-years and station masters (5.7 μT-years. During 464,129 person-years of follow up, 5,413 deaths were recorded and 3,594 deaths were attributed to cardio-vascular diseases. We analyzed data using Cox proportional hazards models. Results For all cardiovascular mortality the hazard ratio compared to station masters was 0.99 (95%CI: 0.91, 1.08 in train drivers, 1.13 (95%CI: 0.98, 1.30 in shunting yard engineers, and 1.09 (95%CI: 1.00, 1.19 in train attendants.Corresponding hazard ratios for arrhythmia related deaths were 1.04 (95%CI: 0.68, 1.59, 0.58 (95%CI: 0.24, 1.37 and 1.30 (95%CI: 0.87, 1.93 and for acute myocardial infarction 1.00 (95%CI: 0.73, 1.36, 1.56 (95%CI: 1.04, 2.32, and 1.14 (95%CI: 0.85, 1.53. The hazard ratio for arrhythmia related deaths per 100 μT-years of cumulative exposure was 0.94 (95%CI: 0.71, 1.24 and 0.91 (95%CI: 0.75, 1.11 for acute myocardial infarction. Conclusion This study provides evidence against an association between long-term occupational exposure to intermittent 16.7 Hz magnetic fields and cardiovascular mortality.

  4. Risks of cardiovascular diseases evolvement and occupational stress

    Directory of Open Access Journals (Sweden)

    Z.F. Gimaeva

    2017-03-01

    Full Text Available Our aim was to study how significant psychosocial factors are in occupational stress and cardiovascular diseases evolvement in workers employed at petrochemical production; we also intended to work out a set of preventive measures. Our hygienic and social-psychological research enabled us to detect factors causing stress evolvement in workers employed at petrochemical production. These factors included chemical impact, noise, unfavorable microclimate, labor hardness and labor intensity. High level of risk for their own lives and responsibility for safety of others, as well as work under time deficiency conditions with increased responsibility for the final results, were the most significant psychosocial factors for workers. In the course of questioning we detected that 74 % machine operators, 63 % tool men working with controllers and automatic devices, and 57 % repairmen mentioned having stress at work. Here 38 % workers gave a subjective estimation of their professional activity as having apparent "stress nature". The questioning revealed that 48 % workers with various occupations had increased parameters as per anxiety scale (HADS; 23 % workers had increased parameters as per depressions scale (HADS. Primary hypertension was the most widely spread nosologic form among chronic non-infectious diseases; it was found in 46.1 % operators and in 45.2 % repairmen dealing with processing stations repair. 30.1 % tool men working with controllers and automatic devices had average occupational causation of primary hypertension by production factors. We detected direct relation between hyperlipidemia and age and working period. We created foundation for preventive measures and worked out a program aimed at increasing resistance to stress at corporate and individual level. It will provide significant social effect and later on economic one. To overcome social stress we need to create safe working conditions at workplaces and to increase labor motivation

  5. Design and development of a new magnetic sensor for stress measurements

    International Nuclear Information System (INIS)

    Aggelopoulos, S

    2016-01-01

    This paper describes the design and the development of a new magnetic sensor for stress measurements using the magnetic Barkhausen noise and the magnetic permeability techniques in ferromagnetic steels. Both techniques together, become an important nondestructive technique, due to its exceptional material and stress characterization capabilities. The correlation of the two methods was investigated. Conclusions were derived based on the experimental results. (paper)

  6. Stress magnetic resonance imaging in coronary artery disease. 11

    International Nuclear Information System (INIS)

    Pennell, D.J.; Underwood, S.R.

    1991-01-01

    The feasibility of MRI of wall motion and cardiovascular haemodynamics has been investigated during pharmacological stress with dipyridamole and dobutamine as pharmacological stressors. The authors conclude that dobutamine is preferable to dipyridamole for inducing myocardial ischemia during imaging. (H.W.). 74 refs.; 8 figs.; 5 tabs

  7. Mechanical stresses and strains in superconducting dipole magnets for high energy accelerators

    International Nuclear Information System (INIS)

    Greben, L.I.; Mironov, E.S.; Moustafin, H.H.

    1979-01-01

    Stress and strain distributions in superconducting dipole magnets were investigated numerically. A finite element computer program was developed to calculate stresses and displacements due to thermal stress, electromagnetic forces and prestressing of structural elements. Real mechanical and thermal properties of superconducting dipole elements are taken into account. Numerical results of stress and strain patterns in dipole magnets are presented

  8. Experiment on relationship between the magnetic gradient of low-carbon steel and its stress

    International Nuclear Information System (INIS)

    Jian Xingliang; Jian Xingchao; Deng Guoyong

    2009-01-01

    In geomagnetic field, a series of tensile experiments on the low-carbon steel sticks were carried out. A special homemade detector was used to measure the magnetic gradient on the material surface. The results showed that the relationship between the magnetic gradient and the stress varied with different conditions of measurement. There was no obvious correlation between the magnetic gradient and the tensile stress if the sample remained on the material test machine. If the sample was taken off from the machine, the measured magnetic gradient was linear with the prior maximum stress. In Nanjing, PR China, a place of 32 o N latitude, the slope of the linear relationship was about 67 (uT/m)/MPa. This offered a new method of non-destructive stress testing by measuring the magnetic gradient on the ferromagnetic component surface. The prior maximum applied stress of the sample could be tested by measuring the present surface magnetic gradient. Actually this phenomenon was the metal magnetic memory (MMM). The magnetic gradient near the stress concentration zone of the sample, the necking point, was much larger than other area. Thus, the hidden damage in the ferromagnetic component could be detected early by measuring the magnetic gradient distribution on its surface. In addition, the magnetic memory signal gradually weakened as the sample was taken off and laid aside. Therefore, it was effective for a given period of time to detect the stress or stress concentration based on the MMM testing.

  9. Cardiovascular magnetic resonance in pericardial diseases

    Directory of Open Access Journals (Sweden)

    Francone Marco

    2009-05-01

    Full Text Available Abstract The pericardium and pericardial diseases in particular have received, in contrast to other topics in the field of cardiology, relatively limited interest. Today, despite improved knowledge of pathophysiology of pericardial diseases and the availability of a wide spectrum of diagnostic tools, the diagnostic challenge remains. Not only the clinical presentation may be atypical, mimicking other cardiac, pulmonary or pleural diseases; in developed countries a shift for instance in the epidemiology of constrictive pericarditis has been noted. Accurate decision making is crucial taking into account the significant morbidity and mortality caused by complicated pericardial diseases, and the potential benefit of therapeutic interventions. Imaging herein has an important role, and cardiovascular magnetic resonance (CMR is definitely one of the most versatile modalities to study the pericardium. It fuses excellent anatomic detail and tissue characterization with accurate evaluation of cardiac function and assessment of the haemodynamic consequences of pericardial constraint on cardiac filling. This review focuses on the current state of knowledge how CMR can be used to study the most common pericardial diseases.

  10. Effect of tensile stress on the 3D reversible and irreversible differential magnetic susceptibilities

    International Nuclear Information System (INIS)

    Mao, Weihua; Atherton, David L.

    2001-01-01

    Magnetic hysteresis loops in three orthogonal directions are measured for a line pipe steel sample while the external magnetic field is applied in a direction perpendicular to the tensile stress direction. The total magnetization vector is calculated. This tends to the stress direction when tensile stress is applied. The reversible and irreversible differential magnetic susceptibilities are derived. It is found that the susceptibilities in all three directions are enhanced with increasing tensile stress, although the increase in the stress direction is much larger than in the other directions. [copyright] 2001 American Institute of Physics

  11. Tailoring of in-plane magnetic anisotropy in polycrystalline cobalt thin films by external stress

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Dileep, E-mail: dkumar@csr.res.in [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Singh, Sadhana [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Vishawakarma, Pramod [School of Nanotechnology, RGPV, Bhopal 462036 (India); Dev, Arun Singh; Reddy, V.R. [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201303 (India)

    2016-11-15

    Polycrystalline Co films of nominal thickness ~180 Å were deposited on intentionally curved Si substrates. Tensile and compressive stresses of 100 MPa and 150 MPa were induced in the films by relieving the curvature. It has been found that, within the elastic limit, presence of stress leads to an in-plane magnetic anisotropy in the film and its strength increases with increasing stress. Easy axis of magnetization in the films is found to be parallel/ transverse to the compressive /tensile stresses respectively. The origin of magnetic anisotropy in the stressed films is understood in terms of magneto- elastic coupling, where the stress try to align the magnetic moments in order to minimize the magneto-elastic as well as anisotropy energy. Tensile stress is also found to be responsible for the surface smoothening of the films, which is attributed to the movement of the atoms associated with the applied stress. The present work provides a possible way to tailor the magnetic anisotropy and its direction in polycrystalline and amorphous films using external stress. - Highlights: • Tensile and compressive stresses were induced in Co films by removing the bending force from the substrates after film deposition. • Controlled external mechanical stress is found to be responsible for magnetic anisotropies in amorphous and polycrystalline thin films, where crystalline anisotropy is absent. • Tensile stress leads to surface smoothening of the polycrystalline Co films.

  12. Brain angiotensin-(1-7)/Mas axis: A new target to reduce the cardiovascular risk to emotional stress.

    Science.gov (United States)

    Fontes, Marco Antônio Peliky; Martins Lima, Augusto; Santos, Robson Augusto Souza dos

    2016-04-01

    Emotional stress is now considered a risk factor for several diseases including cardiac arrhythmias and hypertension. It is well known that the activation of neuroendocrine and autonomic mechanisms features the response to emotional stress. However, its link to cardiovascular diseases and the regulatory mechanisms involved remain to be further comprehended. The renin-angiotensin system (RAS) plays an important role in homeostasis on all body systems. Specifically in the brain, the RAS regulates a number of physiological aspects. Recent data indicate that the activation of angiotensin-converting enzyme/angiotensin II/AT1 receptor axis facilitates the emotional stress responses. On the other hand, growing evidence indicates that its counterregulatory axis, the angiotensin-converting enzyme 2 (ACE2)/(Ang)iotensin-(1-7)/Mas axis, reduces anxiety and attenuates the physiological responses to emotional stress. The present review focuses on angiotensin-(1-7)/Mas axis as a promising target to attenuate the physiological response to emotional stress reducing the risk of cardiovascular diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Internal Stresses in Wires for High Field Magnets

    International Nuclear Information System (INIS)

    Han, K.; Embury, J.D.; Lawson, A.C.; Von Dreele, R.B.; Wood, J.T.; Richardson, J.W. Jr.

    1998-01-01

    The codeformation of Cu-Ag or Cu-Nb composite wires used for high field magnets has a number of important microstructural consequences, including the production of very fine scale structures, the development of very high internal surface area to volume ratios during the drawing and the storage of defects at interphase interfaces. In addition, the fabrication and codeformation of phases which differ in crystal structure, thermal expansion, elastic modulus and lattice parameter lead to the development of short wavelength internal stresses. These internal stresses are measured by neutron diffraction and transmission electron microscopy as a function of the imposed drawing strain. The internal stresses lead to important changes in elastic plastic response which can be related to both magnet design and service life and these aspects will be described in detail

  14. Magnetic hysteresis measurements of thin films under isotropic stress.

    Science.gov (United States)

    Holland, Patrick; Dubey, Archana; Geerts, Wilhelmus

    2000-10-01

    Nowadays, ferromagnetic thin films are widely applied in devices for information technology (credit cards, video recorder tapes, floppies, hard disks) and sensors (air bags, anti-breaking systems, navigation systems). Thus, with the increase in the use of magnetic media continued investigation of magnetic properties of materials is necessary to help in determining the useful properties of materials for new or improved applications. We are currently interested in studying the effect of applied external stress on Kerr hysteresis curves of thin magnetic films. The Ni and NiFe films were grown using DC magnetron sputtering with Ar as the sputter gas (pAr=4 mTorr; Tsub=55-190 C). Seed and cap layers of Ti were used on all films for adhesion and oxidation protection, respectively. A brass membrane pressure cell was designed to apply in-plane isotropic stress to thin films. In this pressure cell, gas pressure is used to deform a flexible substrate onto which a thin magnetic film has been sputtered. The curvature of the samples could be controlled by changing the gas pressure to the cell. Magneto-Optical in-plane hysteresis curves at different values of strain were measured. The results obtained show that the stress sensitivity is dependent on the film thickness. For the 500nm NiFe films, the coercivity strongly decreased as a function of the applied stress.

  15. The role of cardiovascular magnetic resonance in assessment of patients after radical surgical correction of tetralogy of Fallot

    International Nuclear Information System (INIS)

    Genova, K.; Dasheva, A.

    2014-01-01

    Surgical management of tetralogy of Fallot (TOF) results in residual anatomic and functional abnormalities in majority of patients. Primarily considered as a benign pulmonary regurgitation with the time results in right ventricular overload, loses the compensatory mechanisms and irreversible right ventricular dilatation and dysfunction. Cardiovascular magnetic resonance (CMR) has evolved during the last two decades as the reference standard imaging modality to assess the anatomic and functional changes in patients with repaired TOF. This article reviews the role of CMR to assess the right ventricular function and to evaluate the degree of pulmonary regurgitation and comments some technical aspects, based to our experience. Key words: Tetralogy of Fallot. Cardiovascular Magnetic Resonance. Pulmonary regurgitation. Right ventricular assessment

  16. Platelet oxidative stress and its relationship with cardiovascular diseases in type 2 diabetes mellitus patients.

    Science.gov (United States)

    El Haouari, Mohammed

    2017-10-05

    Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases. Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2-, H2O2 or OH- , further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Development of a tensile-stress-induced anisotropy in amorphous magnetic thin films

    International Nuclear Information System (INIS)

    Mandal, K.; Vazquez, M.; Garcia, D.; Castano, F.J.; Prados, C.; Hernando, A.

    2000-01-01

    Magnetic anisotropy was induced in positive magnetostrictive Fe 80 B 20 and negative magnetostrictive Co 75 Si 15 B 10 thin films by developing a tensile stress within the samples. The films were grown on the concave surfaces of mechanically bowed glass substrates. On releasing the substrates from the substrate holders, a tensile stress was developed within the samples that modified the domain structure. As a result of it, a magnetic easy axis parallel to the direction of the stress was induced in FeB sample whereas in CoSiB sample the induced easy axis was perpendicular to the direction of the developed stress. To produce magnetic multilayers with crossed anisotropy, FeB/CoSiB bilayers and FeB/Cu/CoSiB trilayers were grown on bowed substrates. The study of magnetic properties of the multilayers indicates the development of crossed anisotropy within them, particularly when the magnetic layers are separated by a nonmagnetic Cu layer

  18. Mindfulness may both moderate and mediate the effect of physical fitness on cardiovascular responses to stress: a speculative hypothesis

    Science.gov (United States)

    Demarzo, Marcelo M. P.; Montero-Marin, Jesús; Stein, Phyllis K.; Cebolla, Ausiàs; Provinciale, Jaime G.; García-Campayo, Javier

    2014-01-01

    The psychological construct of mindfulness refers to an awareness that emerges by intentionally paying attention to the present experience in a non-judgmental or evaluative way. This particular quality of awareness has been associated to several indicators of physical and psychological health, and can be developed using mindfulness-based interventions (MBIs), and therefore MBIs have been successfully applied as preventive and complementary interventions and therapies in medicine and psychology. Together with quiet sitting and lying meditation practices, mindful physical exercises such as “mindful walking” and “mindful movement” are key elements in MBIs and couple muscular activity with an internally directed focus, improving interoceptive attention to bodily sensations. In addition, MBIs seem to share similar mechanisms with physical fitness (PF) by which they may influence cardiovascular responses to stress. Based on these facts, it is feasible to raise the question of whether physical training itself may induce the development of that particular quality of awareness associated with mindfulness, or if one's dispositional mindfulness (DM) (the tendency to be more mindful in daily life) could moderate the effects of exercise on cardiovascular response to stress. The role of mindfulness as a mediator or moderator of the effect of exercise training on cardiovascular responses to stress has barely been studied. In this study, we have hypothesized pathways (moderation and mediation) by which mindfulness could significantly influence the effects of PF on cardiovascular responses to stress and discussed potential practical ways to test these hypotheses. PMID:24723891

  19. Mindfulness may both moderate and mediate the effect of physical fitness on cardiovascular responses to stress: a speculative hypothesis.

    Directory of Open Access Journals (Sweden)

    Marcelo Marcos Piva Demarzo

    2014-03-01

    Full Text Available The psychological construct of mindfulness refers to an awareness that emerges by intentionally paying attention to the present experience in a non-judgmental or evaluative way. This particular quality of awareness has been associated to several indicators of physical and psychological health, and can be developed using mindfulness-based interventions (MBIs, and therefore MBIs have been successfully applied as preventive and complementary interventions and therapies in medicine and psychology. Together with quiet sitting and lying meditation practices, mindful physical exercises such as mindful walking and mindful movement are key elements in MBIs and couple muscular activity with an internally directed focus, improving interoceptive attention to bodily sensations. In addition, MBIs seem to share similar mechanisms with physical fitness by which they may influence cardiovascular responses to stress. Based on these facts, it is feasible to raise the question of whether physical training itself may induce the development of that particular quality of awareness associated with mindfulness, or if one’s dispositional mindfulness (the tendency to be more mindful in daily life could moderate the effects of exercise on cardiovascular response to stress. The role of mindfulness as a mediator or moderator of the effect of exercise training on cardiovascular responses to stress has barely been studied. In this study, we have hypothesized pathways (moderation and mediation by which mindfulness could significantly influence the effects of physical fitness on cardiovascular responses to stress and have discuss potential practical ways to test these hypotheses.

  20. Mindfulness may both moderate and mediate the effect of physical fitness on cardiovascular responses to stress: a speculative hypothesis.

    Science.gov (United States)

    Demarzo, Marcelo M P; Montero-Marin, Jesús; Stein, Phyllis K; Cebolla, Ausiàs; Provinciale, Jaime G; García-Campayo, Javier

    2014-01-01

    The psychological construct of mindfulness refers to an awareness that emerges by intentionally paying attention to the present experience in a non-judgmental or evaluative way. This particular quality of awareness has been associated to several indicators of physical and psychological health, and can be developed using mindfulness-based interventions (MBIs), and therefore MBIs have been successfully applied as preventive and complementary interventions and therapies in medicine and psychology. Together with quiet sitting and lying meditation practices, mindful physical exercises such as "mindful walking" and "mindful movement" are key elements in MBIs and couple muscular activity with an internally directed focus, improving interoceptive attention to bodily sensations. In addition, MBIs seem to share similar mechanisms with physical fitness (PF) by which they may influence cardiovascular responses to stress. Based on these facts, it is feasible to raise the question of whether physical training itself may induce the development of that particular quality of awareness associated with mindfulness, or if one's dispositional mindfulness (DM) (the tendency to be more mindful in daily life) could moderate the effects of exercise on cardiovascular response to stress. The role of mindfulness as a mediator or moderator of the effect of exercise training on cardiovascular responses to stress has barely been studied. In this study, we have hypothesized pathways (moderation and mediation) by which mindfulness could significantly influence the effects of PF on cardiovascular responses to stress and discussed potential practical ways to test these hypotheses.

  1. Stress induced anisotropy in CoFeMn soft magnetic nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Leary, A. M., E-mail: leary@cmu.edu; Keylin, V.; McHenry, M. E. [Materials Science and Engineering Department, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Ohodnicki, P. R. [Functional Materials Development Division, National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236 (United States)

    2015-05-07

    The use of processing techniques to create magnetic anisotropy in soft magnetic materials is a well-known method to control permeability and losses. In nanocomposite materials, field annealing below the Curie temperature results in uniaxial anisotropy energies up to ∼2 kJ/m{sup 3}. Higher anisotropies up to ∼10 kJ/m{sup 3} result after annealing Fe-Si compositions under stress due to residual stress in the amorphous matrix acting on body centered cubic crystals. This work describes near zero magnetostriction Co{sub 80−x−y}Fe{sub x}Mn{sub y}Nb{sub 4}B{sub 14}Si{sub 2} soft magnetic nanocomposites, where x and y < 8 at.% with close packed crystalline grains that show stress induced anisotropies up to ∼50 kJ/m{sup 3} and improved mechanical properties with respect to Fe-Si compositions. Difference patterns measured using transmission X-ray diffraction show evidence of affine strain with respect to the stress axis.

  2. Flow imaging of the cardiovascular system using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Imai, Hitoshi; Sakakibara, Makoto; Sunami, Yuko

    1988-01-01

    Blood flow images by magnetic resonance imaging (MRI) using a 0.25 T unit were evaluated for nine normal volunteers and 108 subjects with a variety of cardiovascular abnormalities. Using the non-gated short-spin echo (SE) technique, blood flow in the cardiovascular systems was not imaged in the normal volunteers. Using end-systolic and end-diastolic SE techniques for the normal subjects, blood flow in the cardiac chambers was not clearly imaged. Blood flow in the ascending aorta and aortic arch often did not appear in the gated SE images of the normal subjects. However, blood flow in the descending aorta was often observed in the gated SE images. Blood flow imaging was demonstrated by both non-gated and gated SE techniques in regions where blood flow was relatively slow; for example, in the left atrium of mitral stenosis, in an aortic aneurysm, in a false lumen of an aortic dissection, and in the left ventricle having old myocardial infarction. Using the non-gated inversion recovery (IR) technique, no blood flow was imaged in the cardiovascular system except in the left atrium of one case with mitral stenosis. Using the non-gated short SE technique, there was good correlation between the thrombus formation and the presence of blood flow images in the left atria of 17 patients with mitral stenosis, and in the aneurysmal portions of the aorta or in the false lumens of aortic dissection of 18 patients. It was suggested that mural thrombi in such diseases were related to the relatively slow blood flow. Blood flow imaging easily distinguished stagnant blood flow from mural thrombi using non-gated short SE, end-systolic SE, and IR techniques. Thus, blood flow imaging using MRI should become an important means of evaluating the cardiovascular system. (author)

  3. Further evidence for an association between self-reported health and cardiovascular as well as cortisol reactions to acute psychological stress

    NARCIS (Netherlands)

    de Rooij, Susanne R.; Roseboom, Tessa J.

    2010-01-01

    In a recent study, the association between cardiovascular reactions to acute psychological stress and self-reported health was examined. Participants with excellent or good self-reported health exhibited higher cardiovascular reactivity than those who reported fair or poor health. We investigated

  4. Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle

    Directory of Open Access Journals (Sweden)

    Valenti Vitor E

    2012-03-01

    Full Text Available Abstract Background Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS. Methods We evaluated males Wistar rats (320-370 g, which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V. Femoral artery and vein were cannulated for mean arterial pressure (MAP and heart rate (HR measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm. Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 μg/kg, bolus to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, bolus to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 μL injection into the 4th V. Results Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. Conclusion We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.

  5. A pulsed magnetic stress applied to Drosophila melanogaster flies

    International Nuclear Information System (INIS)

    Delle Side, D; Giuffreda, E; Nassisi, V; Velardi, L; Bozzetti, M P; Friscini, A; Specchia, V

    2014-01-01

    We report the development of a system to feed pulsed magnetic stress to biological samples. The device is based on a RLC circuit that transforms the energy stored in a high voltage capacitor into a magnetic field inside a coil. The field has been characterized and we found that charging the capacitor with 24 kV results in a peak field of 0.4 T. In order to test its effect, we applied such a stress to the Drosophila melanogaster model and we examined its bio-effects. We analysed, in the germ cells, the effects on the control of specific DNA repetitive sequences that are activated after different environmental stresses. The deregulation of these sequences causes genomic instability and chromosomes breaks leading to sterility. The magnetic field treatment did not produce effects on repetitive sequences in the germ cells of Drosophila. Hence, this field doesn't produce deleterious effects linked to repetitive sequences derepression.

  6. A pulsed magnetic stress applied to Drosophila melanogaster flies

    Science.gov (United States)

    Delle Side, D.; Bozzetti, M. P.; Friscini, A.; Giuffreda, E.; Nassisi, V.; Specchia, V.; Velardi, L.

    2014-04-01

    We report the development of a system to feed pulsed magnetic stress to biological samples. The device is based on a RLC circuit that transforms the energy stored in a high voltage capacitor into a magnetic field inside a coil. The field has been characterized and we found that charging the capacitor with 24 kV results in a peak field of 0.4 T. In order to test its effect, we applied such a stress to the Drosophila melanogaster model and we examined its bio-effects. We analysed, in the germ cells, the effects on the control of specific DNA repetitive sequences that are activated after different environmental stresses. The deregulation of these sequences causes genomic instability and chromosomes breaks leading to sterility. The magnetic field treatment did not produce effects on repetitive sequences in the germ cells of Drosophila. Hence, this field doesn't produce deleterious effects linked to repetitive sequences derepression.

  7. Effects of Varenicline on Cardiovascular Parameters and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Nurhan Sarıoğlu

    2017-04-01

    Full Text Available Objective: Pharmacotheraphy is recommended for smoking cessation in clinical practice. However, the cardiovascular safety of smoking cessation drugs has been questioned. Our goal is to evaluate the effects of the smoking cessation drug varenicline on some cardiovascular parameters and oxidative stress in subjects. Methods: Twenty-six smokers without cardiovascular diseases and 25 healthy subjects were enrolled in the study. Total oxidant status (TOS, total antioxidant status (TAS, and urotensin II levels were determined in blood samples. Echocardiography was performed in all individuals. Smokers were assessed with the measurements mentioned above at the beginning of the treatment (V0 group and at the end (third month, V3 group. The same measurements were performed once in the control group (C. Results: Aortic strain and distensibility measurements in the V0 group were found to be significantly lower than those in the C group. No significant changes were observed after varenicline treatment. TOS values in the V0 group were found to be higher than those in the V3 and C groups, but these differences were not statistically significant. However, TAS values of the V3 group were found to be significantly lower than those of the V0 group. There were no differences between the groups in terms of diastolic dysfunction and urotensin II levels. Conclusion: Our study revealed that varenicline may decrease TAS in smokers thanks to smoking cessation. Varenicline does not seem to have negative effects on aortic stiffness. Further studies are needed to confirm these results.

  8. Detection of myocardial ischemia by automated, motion-corrected, color-encoded perfusion maps compared with visual analysis of adenosine stress cardiovascular magnetic resonance imaging at 3 T: a pilot study.

    Science.gov (United States)

    Doesch, Christina; Papavassiliu, Theano; Michaely, Henrik J; Attenberger, Ulrike I; Glielmi, Christopher; Süselbeck, Tim; Fink, Christian; Borggrefe, Martin; Schoenberg, Stefan O

    2013-09-01

    The purpose of this study was to compare automated, motion-corrected, color-encoded (AMC) perfusion maps with qualitative visual analysis of adenosine stress cardiovascular magnetic resonance imaging for detection of flow-limiting stenoses. Myocardial perfusion measurements applying the standard adenosine stress imaging protocol and a saturation-recovery temporal generalized autocalibrating partially parallel acquisition (t-GRAPPA) turbo fast low angle shot (Turbo FLASH) magnetic resonance imaging sequence were performed in 25 patients using a 3.0-T MAGNETOM Skyra (Siemens Healthcare Sector, Erlangen, Germany). Perfusion studies were analyzed using AMC perfusion maps and qualitative visual analysis. Angiographically detected coronary artery (CA) stenoses greater than 75% or 50% or more with a myocardial perfusion reserve index less than 1.5 were considered as hemodynamically relevant. Diagnostic performance and time requirement for both methods were compared. Interobserver and intraobserver reliability were also assessed. A total of 29 CA stenoses were included in the analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detection of ischemia on a per-patient basis were comparable using the AMC perfusion maps compared to visual analysis. On a per-CA territory basis, the attribution of an ischemia to the respective vessel was facilitated using the AMC perfusion maps. Interobserver and intraobserver reliability were better for the AMC perfusion maps (concordance correlation coefficient, 0.94 and 0.93, respectively) compared to visual analysis (concordance correlation coefficient, 0.73 and 0.79, respectively). In addition, in comparison to visual analysis, the AMC perfusion maps were able to significantly reduce analysis time from 7.7 (3.1) to 3.2 (1.9) minutes (P < 0.0001). The AMC perfusion maps yielded a diagnostic performance on a per-patient and on a per-CA territory basis comparable with the visual analysis

  9. Stress through the mind of the beholder: preliminary differences in child and maternal perceptions of child stress in relation to child cortisol and cardiovascular activity.

    Science.gov (United States)

    Allwood, Maureen A; Gaffey, Allison E; Vergara-Lopez, Chrystal; Stroud, Laura R

    2017-07-01

    The present study examined associations among parent and child reports of youth's stressful life events (SLEs), perceived stress, and biological measures of stress activity (i.e. cortisol and cardiovascular activity). Examining these aspects of youth stress presents several challenges. Unlike adult studies of individual differences in which information regarding SLEs, perceptions of events, and biological activity are gathered from one individual, assessment of individual differences among children usually involves other informants (e.g. parent). However, parent and child reports of SLEs and the child's psychological response to such events are often discordant. Moreover, examinations of youth perception of stress are hampered by limitations of child cognitive processes, as well as parents' limited knowledge of their child's perception of stress. In a preliminary effort to unscramble the complex effects of youth SLEs and perceived stress in relation to biological response to acute stressors, this study examined 51 boys and girls aged 7-16, with no history of psychopathology or medical concerns. Contrary to hypotheses, findings revealed that compared to actual experiences of stress, perceived stress has greater associations with both cortisol and cardiovascular activity. That is, perceived stress is more biologically salient relative to actual stress. Results also suggest that informant differences may explain some previous inconsistent findings in studies of youth's stress reactivity. The current findings mirror the adult studies that show appraisal and perception of traumatic and stressful events may be more predictive of negative health and mental health outcomes than the severity of the events. Further studies are needed to understand the impact of youth's perceptions of stress on their biological stress reactions and later health outcomes such as clinical disorders.

  10. Effect of mechanical stress on the magnetic properties of amorphous Fe-B ribbons

    International Nuclear Information System (INIS)

    Kecer, J.; Novak, L.

    2011-01-01

    From this point of view, we have dealt with the effect of mechanical stress in this work. It is one of the variables, together with an external magnetic field and temperature, in which it can be expected a significant impact on changes in magnetic properties of amorphous ferromagnets prepared by rapid quenching of the melt. Internal tensions, significantly affecting the magnetic parameters, are introduced into the material already under preparation. Although the rate of internal stresses in amorphous tape is high, we can see significant changes in the measured magnetic parameters induced by mechanical stresses. By applying mechanical stress on amorphous sample Fe 84 B 16 , is highlighted the impact of internal stresses in the direction of stress, which induces the direction of axis of easy magnetising and it results in filling the hysteresis loop to the J axis, coercivity values decreasing by half, constant of magnetoelastic anisotropy decreasing by half and change in the value of magnetostriction. (authors)

  11. The Adverse Effects of Environmental Noise Exposure on Oxidative Stress and Cardiovascular Risk

    Science.gov (United States)

    Sørensen, Mette; Schmidt, Frank; Schmidt, Erwin; Steven, Sebastian; Kröller-Schön, Swenja; Daiber, Andreas

    2018-01-01

    Abstract Epidemiological studies have provided evidence that traffic noise exposure is linked to cardiovascular diseases such as arterial hypertension, myocardial infarction, and stroke. Noise is a nonspecific stressor that activates the autonomous nervous system and endocrine signaling. According to the noise reaction model introduced by Babisch and colleagues, chronic low levels of noise can cause so-called nonauditory effects, such as disturbances of activity, sleep, and communication, which can trigger a number of emotional responses, including annoyance and subsequent stress. Chronic stress in turn is associated with cardiovascular risk factors, comprising increased blood pressure and dyslipidemia, increased blood viscosity and blood glucose, and activation of blood clotting factors, in animal models and humans. Persistent chronic noise exposure increases the risk of cardiometabolic diseases, including arterial hypertension, coronary artery disease, diabetes mellitus type 2, and stroke. Recently, we demonstrated that aircraft noise exposure during nighttime can induce endothelial dysfunction in healthy subjects and is even more pronounced in coronary artery disease patients. Importantly, impaired endothelial function was ameliorated by acute oral treatment with the antioxidant vitamin C, suggesting that excessive production of reactive oxygen species contributes to this phenomenon. More recently, we introduced a novel animal model of aircraft noise exposure characterizing the underlying molecular mechanisms leading to noise-dependent adverse oxidative stress-related effects on the vasculature. With the present review, we want to provide an overview of epidemiological, translational clinical, and preclinical noise research addressing the nonauditory, adverse effects of noise exposure with focus on oxidative stress. Antioxid. Redox Signal. 28, 873–908. PMID:29350061

  12. Responses to reductive stress in the cardiovascular system.

    Science.gov (United States)

    Handy, Diane E; Loscalzo, Joseph

    2017-08-01

    There is a growing appreciation that reductive stress represents a disturbance in the redox state that is harmful to biological systems. On a cellular level, the presence of increased reducing equivalents and the lack of beneficial fluxes of reactive oxygen species can prevent growth factor-mediated signaling, promote mitochondrial dysfunction, increase apoptosis, and decrease cell survival. In this review, we highlight the importance of redox balance in maintaining cardiovascular homeostasis and consider the tenuous balance between oxidative and reductive stress. We explain the role of reductive stress in models of protein aggregation-induced cardiomyopathies, such as those caused by mutations in αB-crystallin. In addition, we discuss the role of NADPH oxidases in models of heart failure and ischemia-reperfusion to illustrate how oxidants may mediate the adaptive responses to injury. NADPH oxidase 4, a hydrogen peroxide generator, also has a major role in promoting vascular homeostasis through its regulation of vascular tone, angiogenic responses, and effects on atherogenesis. In contrast, the lack of antioxidant enzymes that reduce hydrogen peroxide, such as glutathione peroxidase 1, promotes vascular remodeling and is deleterious to endothelial function. Thus, we consider the role of oxidants as necessary signals to promote adaptive responses, such as the activation of Nrf2 and eNOS, and the stabilization of Hif1. In addition, we discuss the adaptive metabolic reprogramming in hypoxia that lead to a reductive state, and the subsequent cellular redistribution of reducing equivalents from NADH to other metabolites. Finally, we discuss the paradoxical ability of excess reducing equivalents to stimulate oxidative stress and promote injury. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Multidirectional flow analysis by cardiovascular magnetic resonance in aneurysm development following repair of aortic coarctation

    Directory of Open Access Journals (Sweden)

    Stalder Aurelien F

    2008-06-01

    Full Text Available Abstract Aneurysm formation is a life-threatening complication after operative therapy in coarctation. The identification of patients at risk for the development of such secondary pathologies is of high interest and requires a detailed understanding of the link between vascular malformation and altered hemodynamics. The routine morphometric follow-up by magnetic resonance angiography is a well-established technique. However, the intrinsic sensitivity of magnetic resonance (MR towards motion offers the possibility to additionally investigate hemodynamic consequences of morphological changes of the aorta. We demonstrate two cases of aneurysm formation 13 and 35 years after coarctation surgery based on a Waldhausen repair with a subclavian patch and a Vosschulte repair with a Dacron patch, respectively. Comprehensive flow visualization by cardiovascular MR (CMR was performed using a flow-sensitive, 3-dimensional, and 3-directional time-resolved gradient echo sequence at 3T. Subsequent analysis included the calculation of a phase contrast MR angiography and color-coded streamline and particle trace 3D visualization. Additional quantitative evaluation provided regional physiological information on blood flow and derived vessel wall parameters such as wall shear stress and oscillatory shear index. The results highlight the individual 3D blood-flow patterns associated with the different vascular pathologies following repair of aortic coarctation. In addition to known factors predisposing for aneurysm formation after surgical repair of coarctation these findings indicate the importance of flow sensitive CMR to follow up hemodynamic changes with respect to the development of vascular disease.

  14. Manufacturing inspection of electrical steels using Magnetic Barkhausen Noise: residual stress detection

    Energy Technology Data Exchange (ETDEWEB)

    Samimi, A.A., E-mail: 9aa8@queensu.ca [Queen' s Univ., Applied Magnetics Group, Kingston, Ontario (Canada); Krause, T.W. [Royal Military College of Canada, NDE Lab., Kingston, Ontario (Canada); Clapham, L. [Queen' s Univ., Applied Magnetics Group, Kingston, Ontario (Canada); Gallaugher, M.; Ding, Y.; Chromik, R. [McGill Univ., Dept. of Mining and Materials Engineering, Montreal, Quebec (Canada)

    2016-09-15

    Non-oriented Electrical Steel (NOES) is the magnetic core lamination material used for flux transfer in rotary machines. The presence of residual stress associated with material processing may be detrimental to magnetic domain structure refinement and as a result, magnetic performance of NOES. Therefore, manufacturing inspection of NOES that identifies the presence of residual stress could contribute to the production of more energy efficient cores. However, standard materials evaluation is limited to destructive and off-line techniques. The present work employed Magnetic Barkhausen Noise (MBN) for nondestructive identification of local residual stress associated with stages in material processing. Analysis of MBN from single strips of NOES demonstrated clear response to applied tensile stress, mechanical shearing, the presence of an insulating coating and punching. The results establish the potential of MBN as a nondestructive testing technology for quality control of electrical steels at various stages of manufacture. (author)

  15. Echocardiography in the Era of Multimodality Cardiovascular Imaging

    Science.gov (United States)

    Shah, Benoy Nalin

    2013-01-01

    Echocardiography remains the most frequently performed cardiac imaging investigation and is an invaluable tool for detailed and accurate evaluation of cardiac structure and function. Echocardiography, nuclear cardiology, cardiac magnetic resonance imaging, and cardiovascular-computed tomography comprise the subspeciality of cardiovascular imaging, and these techniques are often used together for a multimodality, comprehensive assessment of a number of cardiac diseases. This paper provides the general cardiologist and physician with an overview of state-of-the-art modern echocardiography, summarising established indications as well as highlighting advances in stress echocardiography, three-dimensional echocardiography, deformation imaging, and contrast echocardiography. Strengths and limitations of echocardiography are discussed as well as the growing role of real-time three-dimensional echocardiography in the guidance of structural heart interventions in the cardiac catheter laboratory. PMID:23878804

  16. A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress.

    Science.gov (United States)

    Truijen, Jasper; Bundgaard-Nielsen, Morten; van Lieshout, Johannes J

    2010-05-01

    The Frank-Starling mechanism describes the relationship between stroke volume and preload to the heart, or the volume of blood that is available to the heart--the central blood volume. Understanding the role of the central blood volume for cardiovascular control has been complicated by the fact that a given central blood volume may be associated with markedly different central vascular pressures. The central blood volume varies with posture and, consequently, stroke volume and cardiac output (Q) are affected, but with the increased central blood volume during head-down tilt, stroke volume and Q do not increase further indicating that in the supine resting position the heart operates on the plateau of the Frank-Starling curve which, therefore, may be taken as a functional definition of normovolaemia. Since the capacity of the vascular system surpasses the blood volume, orthostatic and environmental stress including bed rest/microgravity, exercise and training, thermal loading, illness, and trauma/haemorrhage is likely to restrict venous return and Q. Consequently the cardiovascular responses are determined primarily by their effect on the central blood volume. Thus during environmental stress, flow redistribution becomes dependent on sympathetic activation affecting not only skin and splanchnic blood flow, but also flow to skeletal muscles and the brain. This review addresses the hypothesis that deviations from normovolaemia significantly influence these cardiovascular responses.

  17. Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Nada Sallam

    2016-01-01

    Full Text Available Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual’s characteristics; therefore, the development of personalized exercise programs is essential.

  18. Cardiovascular magnetic resonance in the follow-up of patients with corrected tetralogy of Fallot: a review

    NARCIS (Netherlands)

    Oosterhof, Thomas; Mulder, Barbara J. M.; Vliegen, Hubert W.; de Roos, Albert

    2006-01-01

    Cardiovascular magnetic resonance (CMR) is becoming an important tool in the clinical management of patients with congenital heart disease. Because of the diverse problems patients may face after initial correction for tetralogy of Fallot and the large amount of CMR techniques that can be applied,

  19. Oxidative stress drivers and modulators in obesity and cardiovascular disease: from biomarkers to therapeutic approach.

    Science.gov (United States)

    Santilli, F; Guagnano, M T; Vazzana, N; La Barba, S; Davi, G

    2015-01-01

    This review article is intended to describe how oxidative stress regulates cardiovascular disease development and progression. Epigenetic mechanisms related to oxidative stress, as well as more reliable biomarkers of oxidative stress, are emerging over the last years as potentially useful tools to design therapeutic approaches aimed at modulating enhanced oxidative stress "in vivo", thereby mitigating the consequent atherosclerotic burden. As a paradigm, we describe the case of obesity, in which the intertwining among oxidative stress, due to caloric overload, chronic low-grade inflammation induced by adipose tissue dysfunction, and platelet activation represents a vicious cycle favoring the progression of atherothrombosis. Oxidative stress is a major player in the pathobiology of cardiovascular disease (CVD). Reactive oxygen species (ROS)- dependent signaling pathways prompt transcriptional and epigenetic dysregulation, inducing chronic low-grade inflammation, platelet activation and endothelial dysfunction. In addition, several oxidative biomarkers have been proposed with the potential to improve current understanding of the mechanisms underlying CVD. These include ROS-generating and/or quenching molecules, and ROS-modified compounds, such as F2-isoprostanes. There is also increasing evidence that noncoding micro- RNA (mi-RNA) are critically involved in post- transcriptional regulation of cell functions, including ROS generation, inflammation, regulation of cell proliferation, adipocyte differentiation, angiogenesis and apoptosis. These molecules have promising translational potential as both markers of disease and site of targeted interventions. Finally, oxidative stress is a critical target of several cardioprotective drugs and nutraceuticals, including antidiabetic agents, statins, renin-angiotensin system blockers, polyphenols and other antioxidants. Further understanding of ROS-generating mechanisms, their biological role as well as potential therapeutic

  20. First measurement of the magnetic turbulence induced Reynolds stress in a tokamak

    International Nuclear Information System (INIS)

    Xu Guosheng; Wan Baonian; Song Mei

    2003-01-01

    Reynolds stress component due to magnetic turbulence was first measured in the plasma edge region of the HT-7 superconducting tokamak using an insertable magnetic probe. A radial gradient of magnetic Reynolds stress was observed to be close to the velocity shear layer location; however, in this experiment its contribution to driving the poloidal flows is small compared to the electrostatic component. The electron heat transport driven by magnetic turbulence is quite small and cannot account for the total energy transport at the plasma edge

  1. Role of the autonomic nervous system and baroreflex in stress-evoked cardiovascular responses in rats.

    Science.gov (United States)

    Dos Reis, Daniel Gustavo; Fortaleza, Eduardo Albino Trindade; Tavares, Rodrigo Fiacadori; Corrêa, Fernando Morgan Aguiar

    2014-07-01

    Restraint stress (RS) is an experimental model to study stress-related cardiovascular responses, characterized by sustained pressor and tachycardiac responses. We used pharmacologic and surgical procedures to investigate the role played by sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS) in the mediation of stress-evoked cardiovascular responses. Ganglionic blockade with pentolinium significantly reduced RS-evoked pressor and tachycardiac responses. Intravenous treatment with homatropine methyl bromide did not affect the pressor response but increased tachycardia. Pretreatment with prazosin reduced the pressor and increased the tachycardiac response. Pretreatment with atenolol did not affect the pressor response but reduced tachycardia. The combined treatment with atenolol and prazosin reduced both pressor and tachycardiac responses. Adrenal demedullation reduced the pressor response without affecting tachycardia. Sinoaortic denervation increased pressor and tachycardiac responses. The results indicate that: (1) the RS-evoked cardiovascular response is mediated by the autonomic nervous system without an important involvement of humoral factors; (2) hypertension results primarily from sympathovascular and sympathoadrenal activation, without a significant involvement of the cardiac sympathetic component (CSNS); (3) the abrupt initial peak in the hypertensive response to restraint is sympathovascular-mediated, whereas the less intense but sustained hypertensive response observed throughout the remaining restraint session is mainly mediated by sympathoadrenal activation and epinephrine release; (4) tachycardia results from CSNS activation, and not from PSNS inhibition; (5) RS evokes simultaneous CSNS and PSNS activation, and heart rate changes are a vector of both influences; (6) the baroreflex is functional during restraint, and modulates both the vascular and cardiac responses to restraint.

  2. Racism and cardiovascular disease: implications for nursing.

    Science.gov (United States)

    Jackson, Jennifer; McGibbon, Elizabeth; Waldron, Ingrid

    2013-01-01

    The social determinants of health (SDH) are recognized as a prominent influence on health outcomes across the lifespan. Racism is identified as a key SDH. In this article, the authors describe the concept of racism as an SDH, its impact in discriminatory actions and inactions, and the implications for cardiovascular nurses. Although research in Canada on the links among racism, stress, and cardiovascular disease is limited, there is growing evidence about the stress of racism and its long-term impact on cardiovascular health. The authors discuss how cardiovascular nursing could be enhanced through an understanding of racism-related stress, and race-based differences in cardiovascular care. The authors conclude with strategies for action to address this nursing concern.

  3. Handling magnetic anisotropy and magnetoimpedance effect in flexible multilayers under external stress

    Energy Technology Data Exchange (ETDEWEB)

    Agra, K.; Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Mori, T.J.A. [Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro, 1000, Guará, 13083-100 Campinas, SP (Brazil); Callegari, G.L.; Dorneles, L.S. [Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Correa, M.A., E-mail: marciocorrea@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2016-12-15

    We investigate the dynamic magnetic response though magnetoimpedance effect of ferromagnetic flexible NiFe/Ta and FeCuNbSiB/Ta multilayers under external stress. We explore the possibility of handling magnetic anisotropy, and consequently the magnetoimpedance effect, of magnetostrictive multilayers deposited onto flexible substrates. We quantify the sensitivity of the multilayers under external stress by calculating the ratio between impedance variations and external stress changes, and show that considerable values can be reached by tuning the magnetic field, frequency, magnetostriction constant, and external stress. The results extend possibilities of application of magnetostrictive multilayers deposited onto flexible substrates when under external stress and place them as very attractive candidates as element sensor for the development of sensitive smart touch sensors. - Highlights: • We investigate the magnetoimpedance effect in magnetostrictive flexible multilayers grown on flexible substrates. • The external applied stress enables to tuning the samples anisotropies, and consequently the MI performance. • The flexible substrate becomes promising candidate for RF-frequency devices.

  4. No effect of creatine supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats

    Directory of Open Access Journals (Sweden)

    Alves Christiano RR

    2012-04-01

    Full Text Available Abstract Background Exacerbated oxidative stress is thought to be a mediator of arterial hypertension. It has been postulated that creatine (Cr could act as an antioxidant agent preventing increased oxidative stress. The aim of this study was to investigate the effects of nine weeks of Cr or placebo supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats (SHR. Findings Lipid hydroperoxidation, one important oxidative stress marker, remained unchanged in the coronary artery (Cr: 12.6 ± 1.5 vs. Pl: 12.2 ± 1.7 nmol·mg-1; p = 0.87, heart (Cr: 11.5 ± 1.8 vs. Pl: 14.6 ± 1.1 nmol·mg-1; p = 0.15, plasma (Cr: 67.7 ± 9.1 vs. Pl: 56.0 ± 3.2 nmol·mg-1; p = 0.19, plantaris (Cr: 10.0 ± 0.8 vs. Pl: 9.0 ± 0.8 nmol·mg-1; p = 0.40, and EDL muscle (Cr: 14.9 ± 1.4 vs. Pl: 17.2 ± 1.5 nmol·mg-1; p = 0.30. Additionally, Cr supplementation affected neither arterial blood pressure nor heart structure in SHR (p > 0.05. Conclusions Using a well-known experimental model of systemic arterial hypertension, this study did not confirm the possible therapeutic effects of Cr supplementation on oxidative stress and cardiovascular dysfunction associated with arterial hypertension.

  5. The influence of the tensile stress on magnetic breakdown in niobium

    International Nuclear Information System (INIS)

    Alekseevskii, N.E.; Glinski, M.; Nizhankovskii, V.I.

    1980-01-01

    It has been shown that magnetic breakdown takes place through the spin-orbital gaps between the hole octahedron of the second Brillouin zone and the open multiply connected surface of hole of the third zone, in two junctions. It is expected that even a small deformation of the sample, lowering the lattice symmetry should eliminate the magnetic breakdown by symmetry point contacts and should change the spectrum of the magnetic breakdown thermopower oscillations. Therefore, the influence of the uniaxial tensile stress on magnetic breakdown was investigated. Experimental details and results are given. The results indicate the change of the spin-orbit gap caused by stress is most probably anisotropic. (U.K.)

  6. Modeling of stress-strain diagram on the basis of magnetic measurements

    International Nuclear Information System (INIS)

    Gorkunov, Eh.S.; Fedotov, V.P.; Bukhvalov, A.B.; Veselov, I.N.

    1997-01-01

    The model of a stress-strain diagram with taking into account the strain hardening and the growth of metal damageing is proposed. The model is applied to calculate a stress-strain curve for continuous cast 45 steel using the results of magnetic properties measuring. The latter permits predicting the durability of construction elements with the use of nondestructive magnetic testing

  7. Stress Response to High Magnetic Fields in Transgenic Arabidopsis thaliana Plants.

    Science.gov (United States)

    Morgan, A. N.; Watson, B. C.; Maloney, J. R.; Meisel, M. W.; Brooks, J. S.; Paul, A.-L.; Ferl, R. J.

    2000-03-01

    With increasingly greater strength magnetic fields becoming available in research and medicine, the response of living tissue exposed to high magnetic fields has come under investigation. In this experiment, genetically engineered arabidopsis plants were exposed to homogeneous magnetic fields of varying strengths using a superconducting NMR magnet (0 to 9 T) at UF and a resistive magnet (0 to 25 T) at the NHMFL. The engineered plants produce the enzyme β-glucaronidase (GUS) when under stressful environmental conditions. The level of GUS activity is determined through qualitative histochemical assays and quantitative fluorometric assays. The control group of plants experienced baseline levels of GUS activity, but some of the plants that were exposed to magnetic fields in excess of 9 T show increased stress response. Additional information is available at http://www.phys.ufl.edu/ ~meisel/maglev.htm.

  8. Stress management at the worksite: reversal of symptoms profile and cardiovascular dysregulation.

    Science.gov (United States)

    Lucini, Daniela; Riva, Silvano; Pizzinelli, Paolo; Pagani, Massimo

    2007-02-01

    Work stress may increase cardiovascular risk either indirectly, by inducing unhealthy life styles, or directly, by affecting the autonomic nervous system and arterial pressure. We hypothesized that, before any apparent sign of disease, work-related stress is already accompanied by alterations of RR variability profile and that a simple onsite stress management program based on cognitive restructuring and relaxation training could reduce the level of stress symptoms, revert stress-related autonomic nervous system dysregulation, and lower arterial pressure. We compared 91 white-collar workers, enrolled at a time of work downsizing (hence, in a stress condition), with 79 healthy control subjects. Psychological profiles were assessed by questionnaires and autonomic nervous system regulation by spectral analysis of RR variability. We also tested a simple onsite stress management program (cognitive restructuring and relaxation training) in a subgroup of workers compared with a sham subgroup (sham program). Workers presented an elevated level of stress-related symptoms and an altered variability profile as compared with control subjects (low-frequency component of RR variability was, respectively, 65.2+/-2 versus 55.3+/-2 normalized units; Pstress management program, which also slightly lowered systolic arterial pressure. No changes were observed in the sham program group. This noninvasive study indicates that work stress is associated with unpleasant symptoms and with an altered autonomic profile and suggests that a stress management program could be implemented at the worksite, with possible preventive advantages for hypertension.

  9. The behavioural, cognitive, and neural corollaries of blunted cardiovascular and cortisol reactions to acute psychological stress

    NARCIS (Netherlands)

    Carroll, Douglas; Ginty, Annie T; Whittaker, Anna C; Lovallo, William R; de Rooij, Susanne R

    Recent research shows that blunted cardiovascular and cortisol reactions to acute psychological stress are associated with adverse behavioural and health outcomes: depression, obesity, bulimia, and addictions. These outcomes may reflect suboptimal functioning of the brain's fronto-limbic systems

  10. Tailoring of magnetic anisotropy of Fe-rich microwires by stress induced anisotropy

    International Nuclear Information System (INIS)

    Zhukov, A.; Zhukova, V.; Larin, V.; Gonzalez, J.

    2006-01-01

    We report on tailoring of magnetic properties and GMI of Fe 69 B 12 Si 14 C 5 glass-coated microwires by stress annealing. The induced magnetic anisotropy field depend on temperature and time of annealing and applied stress. At certain conditions considerable GMI effect (up to 65%) has been achieved. Application of the tensile stress drastically affects the shape of the hysteresis loop of stress-annealed sample and its GMI effect. In this way the shape of the hysteresis loop and GMI effect can by tailored by controllable way

  11. The correlation between mechanical stress and magnetic anisotropy in ultrathin films

    International Nuclear Information System (INIS)

    Sander, D.

    1999-01-01

    The impact of stress-driven structural transitions and of film strain on the magnetic properties of nm ferromagnetic films is discussed. The stress-induced bending of film-substrate composites is analysed to derive information on film stress due to lattice mismatch or due to surface-stress effects. The magneto-elastic coupling in epitaxial films is determined directly from the magnetostrictive bending of the substrate. The combination of stress measurements with magnetic investigations by the magneto-optical Kerr effect (MOKE) reveals the modification of the magnetic anisotropy by film stress. Stress-strain relations are derived for various epitaxial orientations to facilitate the analysis of the substrate curvature. Biaxial film stress and magneto-elastic coupling coefficients are measured in epitaxial Fe films in situ on W single-crystal substrates. Tremendous film stress of more than 10 GPa is measured in pseudomorphic Fe layers, and the important role of film stress as a driving force for the formation of misfit distortions and for inducing changes of the growth mode in monolayer thin films is presented. The direct measurement of the magneto-elastic coupling in epitaxial films proves that the magnitude and sign of the magneto-elastic coupling deviate from the respective bulk value. Even a small film strain of order 0.1% is found to induce a significant change of the effective magneto-elastic coupling coefficient. This peculiar behaviour is ascribed to a second-order strain dependence of the magneto-elastic energy density, in contrast to the linear strain dependence that is valid for bulk samples. (author)

  12. Application of magnetomechanical hysteresis modeling of magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Burkhardt, G.L.

    1993-01-01

    Research was done on the biaxial stress problem accomplished in the first half of the second year. All of the work done was preparatory to magnetic measurements. Issues addressed were: construction of a model for extracting changes in the magnetic properties of a specimen from the readings of an indirect sensor; initial development of a model for how biaxial stress alters the intrinsic magnetic properties of thespecimen; use of finite element stress analysis modeling to determine a detailed shape for the cruciform biaxial stress specimen; and construction of the biaxial stress loading apparatus

  13. An accurate method for determining residual stresses with magnetic non-destructive techniques in welded ferromagnetic steels

    International Nuclear Information System (INIS)

    Vourna, P

    2016-01-01

    The scope of the present research work was to investigate the proper selection criteria for developing a suitable methodology for the accurate determination of residual stresses existing in welded parts. Magnetic non-destructive testing took place by the use of two magnetic non-destructive techniques: by the measurement of the magnetic Barkhausen noise and by the evaluation of the magnetic hysteresis loop parameters. The spatial distribution of residual stresses in welded metal parts by both non-destructive magnetic methods and two diffraction methods was determined. The conduction of magnetic measurements required an initial calibration of ferromagnetic steels. Based on the examined volume of the sample, all methods used were divided into two large categories: the first one was related to the determination of surface residual stress, whereas the second one was related to bulk residual stress determination. The first category included the magnetic Barkhausen noise and the X-ray diffraction measurements, while the second one included the magnetic permeability and the neutron diffraction data. The residual stresses determined by the magnetic techniques were in a good agreement with the diffraction ones. (paper)

  14. The Impact of Escitalopram on Vagally Mediated Cardiovascular Function to Stress and the Moderating Effects of Vigorous Physical Activity: A Randomised Controlled Treatment Study in Healthy Participants

    Directory of Open Access Journals (Sweden)

    Camilla S Hanson

    2013-09-01

    Full Text Available Recent concerns over the impact of antidepressant medications, including the selective serotonin reuptake inhibitors (SSRIs, on cardiovascular function highlight the importance of research on the moderating effects of specific lifestyle factors such as physical activity. Studies in affective neuroscience have demonstrated robust acute effects of SSRIs, yet the impact of SSRIs on cardiovascular stress responses and the moderating effects of physical activity remain to be determined. This was the goal of the present study, which involved a double-blind, randomised, placebo-controlled, cross-over trial of a single-dose of escitalopram (20mg in 44 healthy females; outcomes were heart rate and its variability. Participants engaging in at least 30 minutes of vigorous physical activity at least 3 times per week (regular exercisers showed a more resilient cardiovascular stress response than irregular vigorous exercisers, a finding associated with a moderate effect size (Cohen’s d=0.48. Escitalopram attenuated the cardiovascular stress response in irregular exercisers only (heart rate decreased: Cohen’s d=0.80; heart rate variability increased: Cohen’s d=0.33. Heart rate during stress under escitalopram in the irregular exercisers was similar to that during stress under placebo in regular exercisers.. These findings highlight that the effects of regular vigorous exercise during stress are comparable to the effects of an acute dose of escitalopram, highlighting the beneficial effects of this particular antidepressant in irregular exercisers. Given that antidepressant drugs alone do not seem to protect patients from cardiovascular disease, longitudinal studies are needed to evaluate the impact of exercise on cardiovascular stress responses in patients receiving long-term antidepressant treatment.

  15. Non Hodgkin lymphoma metastasis to the heart detected by cardiovascular magnetic resonance

    International Nuclear Information System (INIS)

    Martinez, Florange; Morales, Marisela; Pedreanez, Norma; Pabon, Luz; Carrillo, Milton

    2009-01-01

    Primary and secondary heart tumors are relatively rare occurrences but usually imply significant treatment decisions. The differential diagnosis among these tumors and other masses can sometimes be difficult and require the use of different imaging modalities to establish a confident verdict. Cardiovascular magnetic resonance CMR imaging is a very useful tool in these cases by allowing for the application of different strategies to better delineate masses, heart structures and adjacent tissues. In this case description, we present a woman with shortness of breath and a paracardiac mass showing how CMR can be applied. (author)

  16. [Cardiovascular hyperreactivity to physical stress predicts high blood pressure in working populations: 4 years follow-up].

    Science.gov (United States)

    Santana López, Sandra; Perdomo Hernández, María del Carmen; Montero Díaz, Rolando

    2014-01-01

    High blood pressure (HBP) is a disease, and as well as a risk factor for other diseases, such as atherosclerosis. Cardiovascular hyperreactivity (CVHR) is a predictor for this disease. The aim of this study was to demonstrate if CVHR to physical stress predicts HBP in working populations. A four year (2008-2012) cohort study was conducted on two population groups: CVHR (48), and normal cardiovascular reactivity (40) after applying the Sustained Weight test. A survival analysis was used to predict HBP, and the χ(2) test and hazard ratio, with a confidence interval of 95%, were used for the statistical analysis. The CVHR is a predictor of HBP, determined by the Sustained Weight test. The working populations can be stratified according to cardiovascular reactivity in order to introduce preventive health actions on the modifiable cardiovascular risk factors of future hypertensives in the workplace. Copyright © 2013 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

  17. Cardiovascular Magnetic Resonance T2-STIR Imaging is Unable to Discriminate Between Intramyocardial Haemorrhage and Microvascular Obstruction

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Pedersen, Steen Fjord; Pedersen, Steen Bønløkke

    2015-01-01

    Recent studies have used cardiovascular magnetic resonance (CMR) and T2-weighted short tau inversion recovery (T2-STIR) imaging to detect intramyocardial haemorrhage (IMH) as a measure of ischemic/reperfusion injury. We investigated the ability of T2-STIR to differentiate between microvascular...

  18. Photoelastic analyses of stresses in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.

    1977-02-01

    Several two-dimensional photoelastic stress analyses were made on models of circular and oval toroidal magnetic field coils for fusion reactors. The circumferential variation of each coil's in-plane magnetic force was simulated by applying different pressures to 16 segmented regions of the inner surface of the models. One special loading fixture was used for the model of each shape and size. Birefringence and isoclinic angles were measured in a transmission polariscope at selected points on the loaded model. Boundary stresses in the cases of known boundary conditions were determined directly from the isochromatics. Separate principal stresses were calculated using the combination of photoelastic information and isopachic data obtained by the electrical analogy method from the solution of Laplace's equation. Comparisons were made between experimental results and those computed using the finite element method. The stress distribution between theoretical and experimental agrees very well, although the finite element method yielded slightly higher stresses than the photoelastic method; further work is needed to resolve this difference. In this investigation several variations of coil geometry and methods of support were evaluated. Based on experimental results, optimum structural designs of toroidal field coils were recommended

  19. Cardiovascular Magnetic Resonance Imaging—Incremental Value in a Series of 361 Patients Demonstrating Cost Savings and Clinical Benefits: An Outcome-Based Study

    Science.gov (United States)

    Hegde, Vinayak A; Biederman, Robert WW; Mikolich, J Ronald

    2017-01-01

    BACKGROUND This study was designed to assess the clinical impact and cost-benefit of cardiovascular magnetic resonance imaging (CMR). In the face of current health care cost concerns, cardiac imaging modalities have come under focused review. Data related to CMR clinical impact and cost-benefit are lacking. METHODS AND RESULTS Retrospective review of 361 consecutive patients (pts) who underwent CMR exams was conducted. Indications for CMR were tabulated for appropriateness criteria. Components of the CMR exam were identified along with evidence of clinical impact. The cost of each CMR exam was ascertained along with cost savings attributable to the CMR exam for calculation of an incremental cost-effectiveness ratio. A total of 354 of 361 pts (98%) had diagnostic quality studies. Of the 361 pts, 350 (97%) had at least 1 published Appropriateness Criterion for CMR. A significant clinical impact attributable to CMR exam results was observed in 256 of 361 pts (71%). The CMR exam resulted in a new diagnosis in 69 of 361 (27%) pts. Cardiovascular magnetic resonance imaging results avoided invasive procedures in 38 (11%) pts and prevented additional diagnostic testing in 26 (7%) pts. Comparison of health care savings using CMR as opposed to current standards of care showed a net cost savings of $833 037, ie, per patient cost savings of $2308. CONCLUSIONS Cardiovascular magnetic resonance imaging provides diagnostic image quality in >98% of cases. Cardiovascular magnetic resonance imaging findings have documentable clinical impact on patient management in 71% of pts undergoing the exam, in a cost beneficial manner. PMID:28579858

  20. Cardiovascular Magnetic Resonance Imaging-Incremental Value in a Series of 361 Patients Demonstrating Cost Savings and Clinical Benefits: An Outcome-Based Study.

    Science.gov (United States)

    Hegde, Vinayak A; Biederman, Robert Ww; Mikolich, J Ronald

    2017-01-01

    This study was designed to assess the clinical impact and cost-benefit of cardiovascular magnetic resonance imaging (CMR). In the face of current health care cost concerns, cardiac imaging modalities have come under focused review. Data related to CMR clinical impact and cost-benefit are lacking. Retrospective review of 361 consecutive patients (pts) who underwent CMR exams was conducted. Indications for CMR were tabulated for appropriateness criteria. Components of the CMR exam were identified along with evidence of clinical impact. The cost of each CMR exam was ascertained along with cost savings attributable to the CMR exam for calculation of an incremental cost-effectiveness ratio. A total of 354 of 361 pts (98%) had diagnostic quality studies. Of the 361 pts, 350 (97%) had at least 1 published Appropriateness Criterion for CMR. A significant clinical impact attributable to CMR exam results was observed in 256 of 361 pts (71%). The CMR exam resulted in a new diagnosis in 69 of 361 (27%) pts. Cardiovascular magnetic resonance imaging results avoided invasive procedures in 38 (11%) pts and prevented additional diagnostic testing in 26 (7%) pts. Comparison of health care savings using CMR as opposed to current standards of care showed a net cost savings of $833 037, ie, per patient cost savings of $2308. Cardiovascular magnetic resonance imaging provides diagnostic image quality in >98% of cases. Cardiovascular magnetic resonance imaging findings have documentable clinical impact on patient management in 71% of pts undergoing the exam, in a cost beneficial manner.

  1. Cardiovascular Magnetic Resonance Imaging—Incremental Value in a Series of 361 Patients Demonstrating Cost Savings and Clinical Benefits: An Outcome-Based Study

    Directory of Open Access Journals (Sweden)

    Vinayak A Hegde

    2017-05-01

    Full Text Available Background: This study was designed to assess the clinical impact and cost-benefit of cardiovascular magnetic resonance imaging (CMR. In the face of current health care cost concerns, cardiac imaging modalities have come under focused review. Data related to CMR clinical impact and cost-benefit are lacking. Methods and Results: Retrospective review of 361 consecutive patients (pts who underwent CMR exams was conducted. Indications for CMR were tabulated for appropriateness criteria. Components of the CMR exam were identified along with evidence of clinical impact. The cost of each CMR exam was ascertained along with cost savings attributable to the CMR exam for calculation of an incremental cost-effectiveness ratio. A total of 354 of 361 pts (98% had diagnostic quality studies. Of the 361 pts, 350 (97% had at least 1 published Appropriateness Criterion for CMR. A significant clinical impact attributable to CMR exam results was observed in 256 of 361 pts (71%. The CMR exam resulted in a new diagnosis in 69 of 361 (27% pts. Cardiovascular magnetic resonance imaging results avoided invasive procedures in 38 (11% pts and prevented additional diagnostic testing in 26 (7% pts. Comparison of health care savings using CMR as opposed to current standards of care showed a net cost savings of $833 037, ie, per patient cost savings of $2308. Conclusions: Cardiovascular magnetic resonance imaging provides diagnostic image quality in >98% of cases. Cardiovascular magnetic resonance imaging findings have documentable clinical impact on patient management in 71% of pts undergoing the exam, in a cost beneficial manner.

  2. Additional diagnostic value of systolic dysfunction induced by dipyridamole stress cardiac magnetic resonance used in detecting coronary artery disease.

    Science.gov (United States)

    Husser, Oliver; Bodí, Vicente; Sanchís, Juan; Mainar, Luis; Núñez, Julio; López-Lereu, María P; Monmeneu, José V; Ruiz, Vicente; Rumiz, Eva; Moratal, David; Chorro, Francisco J; Llácer, Angel

    2009-04-01

    Dipyridamole stress perfusion cardiovascular magnetic resonance (CMR) is used to detect coronary artery disease (CAD). However, few data are available on the diagnostic value of the systolic dysfunction induced by dipyridamole. This study investigated whether the induction of systolic dysfunction supplements the diagnostic information provided by perfusion imaging in the detection of CAD. Overall, 166 patients underwent dipyridamole CMR and quantitative coronary angiography, with CAD being defined as a stenosis > or =70%. Systolic dysfunction at rest, systolic dysfunction with dipyridamole, induced systolic dysfunction, and stress first-pass perfussion deficit (PD) and delayed enhancement were quantified. In the multivariate analysis, PD (hazard ratio [HR]=1.6; 95% confidence interval [CI], 1.33-1.91;Pstatistic for predicting CAD (0.81 vs. 0.87; P=.02). Combining induced systolic dysfunction with perfusion imaging increases the diagnostic accuracy of detecting CAD and enables patients with severe ischemia and a high probability of CAD to be identified.

  3. Thallium stress testing does not predict cardiovascular risk in diabetic patients with end-stage renal disease undergoing cadaveric renal transplantation

    International Nuclear Information System (INIS)

    Holley, J.L.; Fenton, R.A.; Arthur, R.S.

    1991-01-01

    This study assessed the usefulness of thallium stress testing as a predictor of perioperative cardiovascular risk in diabetic patients with end-stage renal disease undergoing cadaveric renal transplantation. Demographic factors influencing the exercise performance in these patients were also examined. The medical records of 189 consecutive patients with diabetic nephropathy who were evaluated for cadaveric renal transplantation were reviewed. Thallium stress testing was the initial examination of cardiovascular status in 141 patients. An adequate examination was one in which at least 70% of maximum heart rate was achieved. A thallium stress test was normal if there were no ST segment depressions on the electrocardiogram and no perfusion abnormalities on the thallium scan. Forty-four patients underwent cardiac catheterization as the initial evaluation (Group C) and four patients underwent transplantation without a formal cardiovascular evaluation (Group D). Sixty-four of the 141 patients undergoing thallium stress testing had an adequate and normal examination (Group A). The incidence of perioperative cardiac events in this group was 2%. Seventy-seven patients (Group B) had an abnormal (n = 41) or an inadequate (n = 36) thallium stress test and most (n = 61) then underwent coronary angiography. The use of beta-blockers was the only predictor of an abnormal or inadequate thallium stress test. Forty-three percent of patients with inadequate or abnormal thallium stress tests had significant coronary artery disease on cardiac catheterization. The perioperative risk of cardiac events was not different in Group A versus Groups B, C, and D combined. Survival of Group A and B patients was not different but was significantly longer than that of Group C patients

  4. Estimation of the iron loss in deep-sea permanent magnet motors considering seawater compressive stress.

    Science.gov (United States)

    Xu, Yongxiang; Wei, Yanyu; Zou, Jibin; Li, Jianjun; Qi, Wenjuan; Li, Yong

    2014-01-01

    Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM). The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress.

  5. Estimation of the Iron Loss in Deep-Sea Permanent Magnet Motors considering Seawater Compressive Stress

    Directory of Open Access Journals (Sweden)

    Yongxiang Xu

    2014-01-01

    Full Text Available Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM. The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress.

  6. Stress induced magnetic-domain evolution in magnetoelectric composites

    Science.gov (United States)

    Trivedi, Harsh; Shvartsman, Vladimir V.; Lupascu, Doru C.; Medeiros, Marco S. A.; Pullar, Robert C.

    2018-06-01

    Local observation of the stress mediated magnetoelectric (ME) effect in composites has gained a great deal of interest over the last decades. However, there is an apparent lack of rigorous methods for a quantitative characterization of the ME effect at the local scale, especially in polycrystalline microstructures. In the present work, we address this issue by locally probing the surface magnetic state of barium titante–hexagonal barium ferrite (BaTiO3–BaFe12O19) ceramic composites using magnetic force microscopy (MFM). The effect of the piezoelectrically induced local stress on the magnetostrictive component (BaFe12O19, BaM) was observed in the form of the evolution of the magnetic domains. The local piezoelectric stress was induced by applying a voltage to the neighboring BaTiO3 grains, using a conductive atomic force microscopy tip. The resulting stochastic evolution of magnetic domains was studied in the context of the induced magnetoelastic anisotropy. In order to overcome the ambiguity in the domain changes observed by MFM, certain generalizations about the observed MFM contrast are put forward, followed by application of an algorithm for extracting the average micromagnetic changes. An average change in domain wall thickness of 50 nm was extracted, giving a lower limit on the corresponding induced magnetoelastic anisotropy energy. Furthermore, we demonstrate that this induced magnetomechanical energy is approximately equal to the K1 magnetocrystalline anisotropy constant of BaM, and compare it with a modeled value of applied elastic energy density. The comparison allowed us to judge the quality of the interfaces in the composite system, by roughly gauging the energy conversion ratio.

  7. Pulmonary Arterial Hypertension: Use of Delayed Contrast-Enhanced Cardiovascular Magnetic Resonance in Risk Assessment

    International Nuclear Information System (INIS)

    Bessa, Luiz Gustavo Pignataro; Junqueira, Flávia Pegado; Bandeira, Marcelo Luiz da Silva; Garcia, Marcelo Iorio; Xavier, Sérgio Salles; Lavall, Guilherme; Torres, Diego; Waetge, Daniel

    2013-01-01

    Pulmonary arterial hypertension is a severe and progressive disease. Its early diagnosis is the greatest clinical challenge. To evaluate the presence and extension of the delayed myocardial contrast-enhanced cardiovascular magnetic resonance, as well as to verify if the percentage of the myocardial fibrosis mass is a severity predictor. Cross-sectional study with 30 patients with pulmonary arterial hypertension of groups I and IV, subjected to clinical, functional and hemodynamic evaluation, and to cardiac magnetic resonance. The mean age of patients was 52 years old, with female predominance (77%). Among the patients, 53% had right ventricular failure at diagnosis, and 90% were in functional class II/III. The mean of the 6-minute walk test was 395m. In hemodynamic study with right catheterism, the mean average pulmonary arterial pressure was 53.3mmHg, of the cardiac index of 2.1L/ min.m 2 , and median right atrial pressure was 13.5 mmHg. Delayed myocardial contrast enhanced cardiovascular magnetic resonance was found in 28 patients. The mean fibrosis mass was 9.9 g and the median percentage of fibrosis mass was 6.17%. The presence of functional class IV, right ventricular failure at diagnosis, 6-minute walk test < 300 meters and right atrial pressure ≥ 15 mmHg, with cardiac index < 2.0 L/ min.m 2 , there was a relevant association with the increased percentage of myocardial fibrosis. The percentage of the myocardial fibrosis mass indicates a non-invasive marker with promising perspectives in identifying patients with high risk factors for pulmonary hypertension

  8. Pulmonary Arterial Hypertension: Use of Delayed Contrast-Enhanced Cardiovascular Magnetic Resonance in Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bessa, Luiz Gustavo Pignataro, E-mail: lgpignataro@ig.com.br; Junqueira, Flávia Pegado; Bandeira, Marcelo Luiz da Silva; Garcia, Marcelo Iorio; Xavier, Sérgio Salles; Lavall, Guilherme; Torres, Diego; Waetge, Daniel [Hospital Universitário Clementino Fraga Filho, Ilha do Fundão, RJ (Brazil)

    2013-10-15

    Pulmonary arterial hypertension is a severe and progressive disease. Its early diagnosis is the greatest clinical challenge. To evaluate the presence and extension of the delayed myocardial contrast-enhanced cardiovascular magnetic resonance, as well as to verify if the percentage of the myocardial fibrosis mass is a severity predictor. Cross-sectional study with 30 patients with pulmonary arterial hypertension of groups I and IV, subjected to clinical, functional and hemodynamic evaluation, and to cardiac magnetic resonance. The mean age of patients was 52 years old, with female predominance (77%). Among the patients, 53% had right ventricular failure at diagnosis, and 90% were in functional class II/III. The mean of the 6-minute walk test was 395m. In hemodynamic study with right catheterism, the mean average pulmonary arterial pressure was 53.3mmHg, of the cardiac index of 2.1L/ min.m{sup 2}, and median right atrial pressure was 13.5 mmHg. Delayed myocardial contrast enhanced cardiovascular magnetic resonance was found in 28 patients. The mean fibrosis mass was 9.9 g and the median percentage of fibrosis mass was 6.17%. The presence of functional class IV, right ventricular failure at diagnosis, 6-minute walk test < 300 meters and right atrial pressure ≥ 15 mmHg, with cardiac index < 2.0 L/ min.m{sup 2}, there was a relevant association with the increased percentage of myocardial fibrosis. The percentage of the myocardial fibrosis mass indicates a non-invasive marker with promising perspectives in identifying patients with high risk factors for pulmonary hypertension.

  9. Cardiovascular magnetic resonance frontiers: Tissue characterisation with mapping

    Directory of Open Access Journals (Sweden)

    Rebecca Schofield

    2016-11-01

    Full Text Available The clinical use of cardiovascular magnetic resonance (CMR imaging has expanded rapidly over the last decade. Its role in cardiac morphological and functional assessment is established, with perfusion and late gadolinium enhancement (LGE imaging for scar increasingly used in day-to-day clinical decision making. LGE allows a virtual histological assessment of the myocardium, with the pattern of scar suggesting disease aetiology, and the extent of predicting risk. However, even combined, the full range of pathological processes occurring in the myocardium are not interrogated. Mapping is a new frontier where the intrinsic magnetic properties of heart muscle are measured to probe further. T1, T2 and T2* mapping measures the three fundamental tissue relaxation rate constants before contrast, and the extracellular volume (ECV after contrast. These are displayed in colour, often providing an immediate appreciation of pathology. These parameters are differently sensitive to pathologies. Iron (cardiac siderosis, intramyocardial haemorrhage makes T1, T2 and T2* fall. T2 also falls with fat infiltration (Fabry disease. T2 increases with oedema (acute infarction, takotsubo cardiomyopathy, myocarditis, rheumatological disease. Native T1 increases with fibrosis, oedema and amyloid. Some of these changes are large (e.g. iron, oedema, amyloid, others more modest (diffuse fibrosis. They can be used to detect early disease, distinguish aetiology and, in some circumstances, guide therapy. In this review, we discuss these processes, illustrating clinical application and future advances.

  10. Modulated magnetic structure of an inhomogeneous stressed single crystal FeBO3

    International Nuclear Information System (INIS)

    Sharipiv, M.Z.; Dzhuraev, D.R.; Sokolov, B.Yu.; Kurbanov, M.

    2010-01-01

    With the help of low-symmetry mechanical stresses, we induced an additional spatially inhomogeneous anisotropy in the basal plane of a single crystal FeBO 3 . By the magnetooptical method, we study the effect of an inhomogeneous magnetic anisotropy on the magnetic state of this easy-plane weak ferromagnetic. It is established that, at the magnetization of inhomogeneously stressed FeBO 3 in the basal plane near some separated direction, the crystal transits from the homogeneous state into a spatially modulated magnetic state. The latter can be represented in the form of a static spin wave, in which a local vector of ferromagnetism oscillates near the direction of the mean magnetization of a crystal, by remaining in the basal plane.

  11. Non collinear magnetic phase of the inhomogeneously stressed FeBO3 monocrystals

    International Nuclear Information System (INIS)

    Sharipov, M.Z.

    2011-01-01

    With the help of low-symmetry mechanical stresses, an additional spatially inhomogeneous anisotropy in the basal plane of a single crystal FeBO 3 has been induced. By the magnetooptical method, an effect of the inhomogeneous magnetic anisotropy on the magnetic state of this easy-plane weak ferromagnetic has been investigated. It is established that at the magnetization of inhomogeneously stressed FeBO 3 in the basal plane near the separated direction, the crystal turns from the homogeneous state into a spatially modulated magnetic state. The latter can be represented in the form of a static spin wave, in which a local vector of ferromagnetism oscillates near the direction of the mean magnetization of a crystal, remaining in the basal plane. (authors)

  12. Artificially controlled stress anisotropy and magnetic properties of FeTaN thin films

    International Nuclear Information System (INIS)

    Deng, H.; Jarratt, J.D.; Minor, M.K.; Barnard, J.A.

    1997-01-01

    This article presents a new method of investigating internal stress effects on thin film magnetic properties, in this case magnetically soft FeTaN sputtered films. The FeTaN films were deposited on a series of oxidized silicon (111) substrates prestressed to different degrees. During sputtering all the deposition conditions were kept exactly the same for all the samples. However, anisotropic stresses with different amplitudes are systematically introduced into the films when the prestressed wafers were released. In this way, FeTaN films with compressive stress varying from 80 to 608 MPa are produced. We found that the saturation magnetostriction (λ s ), anisotropy field (H k ), initial permeability (μ i ) as well as easy axis orientation of FeTaN thin films are strongly affected by the induced stress anisotropy. A stress ratio concept is proposed as a measure of the degree of the stress anisotropy. Models for easy-hard axis switching induced by stress for magnetic films with positive magnetostriction are discussed. copyright 1997 American Institute of Physics

  13. Adolescent vulnerability to cardiovascular consequences of chronic social stress: Immediate and long-term effects of social isolation during adolescence.

    Science.gov (United States)

    Cruz, Fábio C; Duarte, Josiane O; Leão, Rodrigo M; Hummel, Luiz F V; Planeta, Cleopatra S; Crestani, Carlos C

    2016-01-01

    It has been demonstrated that disruption of social bonds and perceived isolation (loneliness) are associated with an increased risk of cardiovascular morbidity and mortality. Adolescence is proposed as a period of vulnerability to stress. Nevertheless, the impact of chronic social stress during this ontogenic period in cardiovascular function is poorly understood. Therefore, the purpose of this study was to compare the impact in cardiovascular function of social isolation for 3 weeks in adolescent and adult male rats. Also, the long-term effects of social isolation during adolescence were investigated longitudinally. Social isolation reduced body weight in adolescent, but not in adult animals. Disruption of social bonds during adolescence increased arterial pressure without affecting heart rate and pulse pressure (PP). Nevertheless, social isolation in adulthood reduced systolic arterial pressure and increased diastolic arterial pressure, which in turn decreased PP without affecting mean arterial pressure. Cardiovascular changes in adolescents, but not adults, were followed by facilitation of both baroreflex sensitivity and vascular reactivity to the vasodilator agent acetylcholine. Vascular responsiveness to either the vasodilator agent sodium nitroprusside or the vasoconstrictor agent phenylephrine was not affected by social isolation. Except for the changes in body weight and baroreflex sensitivity, all alterations evoked by social isolation during adolescence were reversed in adulthood after moving animals from isolated to collective housing. These findings suggest a vulnerability of adolescents to the effects of chronic social isolation in cardiovascular function. However, results indicate minimal cardiovascular consequences in adulthood of disruption of social bonds during adolescence. © 2015 Wiley Periodicals, Inc.

  14. A Unique "Angiotensin-Sensitive" Neuronal Population Coordinates Neuroendocrine, Cardiovascular, and Behavioral Responses to Stress.

    Science.gov (United States)

    de Kloet, Annette D; Wang, Lei; Pitra, Soledad; Hiller, Helmut; Smith, Justin A; Tan, Yalun; Nguyen, Dani; Cahill, Karlena M; Sumners, Colin; Stern, Javier E; Krause, Eric G

    2017-03-29

    Stress elicits neuroendocrine, autonomic, and behavioral responses that mitigate homeostatic imbalance and ensure survival. However, chronic engagement of such responses promotes psychological, cardiovascular, and metabolic impairments. In recent years, the renin-angiotensin system has emerged as a key mediator of stress responding and its related pathologies, but the neuronal circuits that orchestrate these interactions are not known. These studies combine the use of the Cre-recombinase/loxP system in mice with optogenetics to structurally and functionally characterize angiotensin type-1a receptor-containing neurons of the paraventricular nucleus of the hypothalamus, the goal being to determine the extent of their involvement in the regulation of stress responses. Initial studies use neuroanatomical techniques to reveal that angiotensin type-1a receptors are localized predominantly to the parvocellular neurosecretory neurons of the paraventricular nucleus of the hypothalamus. These neurons are almost exclusively glutamatergic and send dense projections to the exterior portion of the median eminence. Furthermore, these neurons largely express corticotrophin-releasing hormone or thyrotropin-releasing hormone and do not express arginine vasopressin or oxytocin. Functionally, optogenetic stimulation of these neurons promotes the activation of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes, as well as a rise in systolic blood pressure. When these neurons are optogenetically inhibited, the activity of these neuroendocrine axes are suppressed and anxiety-like behavior in the elevated plus maze is dampened. Collectively, these studies implicate this neuronal population in the integration and coordination of the physiological responses to stress and may therefore serve as a potential target for therapeutic intervention for stress-related pathology. SIGNIFICANCE STATEMENT Chronic stress leads to an array of physiological responses that ultimately

  15. Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings

    Energy Technology Data Exchange (ETDEWEB)

    Stegemann, Robert, E-mail: Robert.Stegemann@bam.de [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); Cabeza, Sandra; Lyamkin, Viktor; Bruno, Giovanni; Pittner, Andreas [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); Wimpory, Robert; Boin, Mirko [HZB Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Kreutzbruck, Marc [Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12200 Berlin (Germany); IKT, University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart (Germany)

    2017-03-15

    The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction (ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth. - Highlights: • Comparison of magnetic microstructure with neutron diffraction stress analysis. • High spatial resolution magnetic stray field images of hypereutectoid TIG welds. • Spatial variations of the stray fields are below the magnetic field of the earth. • GMR spin valve gradiometer arrays adapted for the evaluation of magnetic microstructures. • Magnetic stray fields are closely linked to microstructure of the material.

  16. Performance feedback, self-esteem, and cardiovascular adaptation to recurring stressors.

    Science.gov (United States)

    Brown, Eoin G; Creaven, Ann-Marie

    2017-05-01

    This study sought to examine the effects of performance feedback and individual differences in self-esteem on cardiovascular habituation to repeat stress exposure. Sixty-six university students (n = 39 female) completed a self-esteem measure and completed a cardiovascular stress-testing protocol involving repeated exposure to a mental arithmetic task. Cardiovascular functioning was sampled across four phases: resting baseline, initial stress exposure, a recovery period, and repeated stress exposure. Participants were randomly assigned to receive fictional positive feedback, negative feedback, or no feedback following the recovery period. Negative feedback was associated with a sensitized blood pressure response to a second exposure of the stress task. Positive feedback was associated with decreased cardiovascular and psychological responses to a second exposure. Self-esteem was also found to predict reactivity and this interacted with the type of feedback received. These findings suggest that negative performance feedback sensitizes cardiovascular reactivity to stress, whereas positive performance feedback increases both cardiovascular and psychological habituation to repeat exposure to stressors. Furthermore, an individual's self-esteem also appears to influence this process.

  17. Oxidative Stress in Cardiovascular Diseases: Involvement of Nrf2 Antioxidant Redox Signaling in Macrophage Foam Cells Formation

    Directory of Open Access Journals (Sweden)

    Bee Kee Ooi

    2017-11-01

    Full Text Available Oxidative stress is an important risk factor contributing to the pathogenesis of cardiovascular diseases. Oxidative stress that results from excessive reactive oxygen species (ROS production accounts for impaired endothelial function, a process which promotes atherosclerotic lesion or fatty streaks formation (foam cells. Nuclear factor erythroid 2-related factor 2 (Nrf2 is a transcription factor involved in cellular redox homeostasis. Upon exposure to oxidative stress, Nrf2 is dissociated from its inhibitor Keap-1 and translocated into the nucleus, where it results in the transcriptional activation of cell defense genes. Nrf2 has been demonstrated to be involved in the protection against foam cells formation by regulating the expression of antioxidant proteins (HO-1, Prxs, and GPx1, ATP-binding cassette (ABC efflux transporters (ABCA1 and ABCG1 and scavenger receptors (scavenger receptor class B (CD36, scavenger receptor class A (SR-A and lectin-type oxidized LDL receptor (LOX-1. However, Nrf2 has also been reported to exhibit pro-atherogenic effects. A better understanding on the mechanism of Nrf2 in oxidative stress-induced cardiac injury, as well as the regulation of cholesterol uptake and efflux, are required before it can serve as a novel therapeutic target for cardiovascular diseases prevention and treatment.

  18. Effects of nitric oxide synthesis inhibitor or fluoxetine treatment on depression-like state and cardiovascular changes induced by chronic variable stress in rats.

    Science.gov (United States)

    Almeida, Jeferson; Duarte, Josiane O; Oliveira, Leandro A; Crestani, Carlos C

    2015-01-01

    Comorbidity between mood disorders and cardiovascular disease has been described extensively. However, available antidepressants can have cardiovascular side effects. Treatment with selective inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant effects, but whether the antidepressant-like effects of these drugs are followed by cardiovascular changes has not been previously investigated. Here, we tested in male rats exposed to chronic variable stress (CVS) the hypothesis that nNOS blockers are advantageous compared with conventional antidepressants in terms of cardiovascular side effects. We compared the effects of chronic treatment with the preferential nNOS inhibitor 7-nitroindazole (7-NI) with those evoked by the conventional antidepressant fluoxetine on alterations that are considered as markers of depression (immobility in the forced swimming test, FST, decreased body weight gain and increased plasma corticosterone concentration) and cardiovascular changes caused by CVS. Rats were exposed to a 14-day CVS protocol, while being concurrently treated daily with either 7-NI (30 mg/kg) or fluoxetine (10 mg/kg). Fluoxetine and 7-NI prevented the increase in immobility in the FST induced by CVS and reduced plasma corticosterone concentration in stressed rats. Both these treatments also prevented the CVS-evoked reduction of the depressor response to vasodilator agents and baroreflex changes. Fluoxetine and 7-NI-induced cardiovascular changes independent of stress exposure, including cardiac autonomic imbalance, increased intrinsic heart rate and vascular sympathetic modulation, a reduction of the pressor response to vasoconstrictor agents, and impairment of baroreflex activity. Altogether, these findings provide evidence that fluoxetine and 7-NI have similar effects on the depression-like state induced by CVS and on cardiovascular function.

  19. Cardiovascular and immune responses to acute psychological stress in young and old women: a meta-analysis

    NARCIS (Netherlands)

    Benschop, R. J.; Geenen, R.; Mills, P. J.; Naliboff, B. D.; Kiecolt-Glaser, J. K.; Herbert, T. B.; van der Pompe, G.; Miller, G. E.; Matthews, K. A.; Godaert, G. L.; Gilmore, S. L.; Glaser, R.; Heijnen, C. J.; Dopp, J. M.; Bijlsma, J. W.; Solomon, G. F.; Cacioppo, J. T.

    1998-01-01

    To describe the relationships between cardiovascular and natural killer (NK) cell number changes on acute psychological stress in women. Data from eight different studies were analyzed. A total of 128 healthy female subjects, 85 younger (18-45 years) and 43 older (49-87 years), had been subjected to

  20. A new oxidative stress model, 2,2-azobis(2-amidinopropane dihydrochloride induces cardiovascular damages in chicken embryo.

    Directory of Open Access Journals (Sweden)

    Rong-Rong He

    Full Text Available It is now well established that the developing embryo is very sensitive to oxidative stress, which is a contributing factor to pregnancy-related disorders. However, little is known about the effects of reactive oxygen species (ROS on the embryonic cardiovascular system due to a lack of appropriate ROS control method in the placenta. In this study, a small molecule called 2,2-azobis(2-amidinopropane dihydrochloride (AAPH, a free radicals generator, was used to study the effects of oxidative stress on the cardiovascular system during chick embryo development. When nine-day-old (stage HH 35 chick embryos were treated with different concentrations of AAPH inside the air chamber, it was established that the LD50 value for AAPH was 10 µmol/egg. At this concentration, AAPH was found to significantly reduce the density of blood vessel plexus that was developed in the chorioallantoic membrane (CAM of HH 35 chick embryos. Impacts of AAPH on younger embryos were also examined and discovered that it inhibited the development of vascular plexus on yolk sac in HH 18 embryos. AAPH also dramatically repressed the development of blood islands in HH 3+ embryos. These results implied that AAPH-induced oxidative stress could impair the whole developmental processes associated with vasculogenesis and angiogenesis. Furthermore, we observed heart enlargement in the HH 40 embryo following AAPH treatment, where the left ventricle and interventricular septum were found to be thickened in a dose-dependent manner due to myocardiac cell hypertrophy. In conclusion, oxidative stress, induced by AAPH, could lead to damage of the cardiovascular system in the developing chick embryo. The current study also provided a new developmental model, as an alternative for animal and cell models, for testing small molecules and drugs that have anti-oxidative activities.

  1. Problematic Internet use, excessive alcohol consumption, their comorbidity and cardiovascular and cortisol reactions to acute psychological stress in a student population.

    Science.gov (United States)

    Bibbey, Adam; Phillips, Anna C; Ginty, Annie T; Carroll, Douglas

    2015-06-01

    Problematic Internet use and excessive alcohol consumption have been associated with a host of maladaptive outcomes. Further, low (blunted) cardiovascular and stress hormone (e.g. cortisol) reactions to acute psychological stress are a feature of individuals with a range of adverse health and behavioural characteristics, including dependencies such as tobacco and alcohol addiction. The present study extended this research by examining whether behavioural dependencies, namely problematic Internet use, excessive alcohol consumption, and their comorbidity would also be associated with blunted stress reactivity. A large sample of university students (N = 2313) were screened using Internet and alcohol dependency questionnaires to select four groups for laboratory testing: comorbid Internet and alcohol dependence (N = 17), Internet dependence (N = 17), alcohol dependence (N = 28), and non-dependent controls (N = 26). Cardiovascular activity and salivary cortisol were measured at rest and in response to a psychological stress protocol comprising of mental arithmetic and public speaking tasks. Neither problematic Internet behaviour nor excessive alcohol consumption, either individually or in combination, were associated with blunted cardiovascular or cortisol stress reactions. Discussion It is possible that problematic Internet behaviour and excessive alcohol consumption in a student population were not related to physiological reactivity as they may not reflect ingrained addictions but rather an impulse control disorder and binging tendency. The present results serve to indicate some of the limits of the developing hypothesis that blunted stress reactivity is a peripheral marker of the central motivational dysregulation in the brain underpinning a wide range of health and behavioural problems.

  2. Magnetic resonance imaging of the cardiovascular system: present state of the art and future potential

    International Nuclear Information System (INIS)

    Jacobson, H.G.

    1988-01-01

    State-of-the-art magnetic resonance imaging (MRI) generates high-resolution images of the cardiovascular system. Conventional MRI techniques provide images in six to ten minutes per tomographic slice. New strategies have substantially improved the speed of imaging. The technology is relatively expensive, and its cost-effectiveness remains to be defined in relation to other effective, less expensive, and noninvasive technologies, such as echocardiography and nuclear medicine. The ultimate role of MRI will depend on several factors, including the development of specific applications such as (1) noninvasive angiography, especially of the coronary arteries;(2) noninvasive, high-resolution assessment of regional myocardial blood flow distribution (e.g., using paramagnetic contrast agents); (3) characterization of myocardial diseases using proton-relaxation property changes; and (4) evaluation of in vivo myocardial biochemistry. The three-dimensional imaging capability and the ability to image cardiovascular structures without contrast material give MRI a potential advantage over existing noninvasive diagnostic imaging techniques. This report analyzes current applications of MRI to the cardiovascular system and speculates on their future

  3. Magnetic property variation in carbon steel and chrome-molybdenum steel as a function of uniaxial stress noncoaxial with the magnetic field (abstract)

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kaminski, D.A.; Jiles, D.C.; Biner, S.B.

    1993-01-01

    Magnescope 1 magnetic measurements were made on carbon steel specimens ranging from 0.1--0.8 wt %C and on chrome-molybdenum steel specimens cut from electric power plant pipes previously in service. The carbon steel specimens were heat-treated using three procedures: (1) spheroidization, (2) quenching, and (3) quench and tempering. The specimens were subjected to uniaxial tension up to 40 ksi. The inspection head was aligned so that the magnetic field was oriented at different angles with respect to the stress axis. Magnetic properties (such as coercivity and maximum differential permeability) were extracted from digitized magnetic hysteresis loop measurements. Magnetic properties were studied as a function of stress at each angle of stress-field orientation. To our knowledge, such a comprehensive study of noncoaxial stress and field effects has never been accomplished before for such a wide variety of steel specimens. Results for the various materials are presented for different orientation angles and compared to numerical results from the noncoaxial magnetomechanical hysteresis model of Sablik et al. 2

  4. Obstructive Sleep Apnea, Oxidative Stress and Cardiovascular Disease: Lessons from Animal Studies

    Directory of Open Access Journals (Sweden)

    Rio Dumitrascu

    2013-01-01

    Full Text Available Obstructive sleep apnea (OSA is an independent risk factor for cardiovascular (CV diseases such as arterial hypertension, heart failure, and stroke. Based on human research, sympathetic activation, inflammation, and oxidative stress are thought to play major roles in the pathophysiology of OSA-related CV diseases. Animal models of OSA have shown that endothelial dysfunction, vascular remodelling, and systemic and pulmonary arterial hypertension as well as heart failure can develop in response to chronic intermittent hypoxia (CIH. The available animal data are clearly in favour of oxidative stress playing a key role in the development of all of these CV manifestations of OSA. Presumably, the oxidative stress is due to an activation of NADPH oxidase and other free oxygen radicals producing enzymes within the CV system as evidenced by data from knockout mice and pharmacological interventions. It is hoped that animal models of OSA-related CV disease will continue to contribute to a deeper understanding of their underlying pathophysiology and will foster the way for the development of cardioprotective treatment options other than conventional CPAP therapy.

  5. Obstructive Sleep Apnea, Oxidative Stress, and Cardiovascular Disease: Evidence from Human Studies

    Directory of Open Access Journals (Sweden)

    Hans-Joachim Eisele

    2015-01-01

    Full Text Available Obstructive sleep apnea (OSA is a frequent disease mainly affecting obese people and caused by repetitive collapse of the upper airways during sleep. The increased morbidity and mortality of OSA are mainly thought to be the consequence of its adverse effects on cardiovascular (CV health. In this context, oxidative stress induced by nocturnal intermittent hypoxia has been identified to play a major role. This is suggested by biomarker studies in OSA patients showing excessively generated reactive oxygen species from leukocytes, reduced plasma levels of nitrite and nitrate, increased lipid peroxidation, and reduced antioxidant capacity. Biopsy studies complement these findings by demonstrating reduced endothelial nitric oxide synthase expression and increased nitrotyrosine immunofluorescence in the vasculature of these patients. Furthermore, oxidative stress in OSA correlates with surrogate markers of CV disease such as endothelial function, intima-media thickness, and high blood pressure. Continuous positive airway pressure therapy reverses oxidative stress in OSA. The same may be true for antioxidants; however, more studies are needed to clarify this issue.

  6. Posttraumatic stress disorder and responses to couple conflict: implications for cardiovascular risk.

    Science.gov (United States)

    Caska, Catherine M; Smith, Timothy W; Renshaw, Keith D; Allen, Steven N; Uchino, Bert N; Birmingham, Wendy; Carlisle, McKenzie

    2014-11-01

    Posttraumatic stress disorder (PTSD) is associated with increased risk of coronary heart disease (CHD) and difficulties in intimate relationships. Greater frequency and severity of couple conflict and greater cardiovascular reactivity to such conflict might contribute to CHD risk in those with PTSD, but affective and physiological responses to couple conflict have not been examined previously in this population. In a preliminary test of this hypothesis, 32 male veterans of the Iraq and Afghanistan Wars with PTSD and their female partners, and 33 control male veterans without PTSD and their female partners completed relationship quality assessments and a conflict discussion task. PTSD diagnosis was confirmed through diagnostic interviews and questionnaires. State anger, state anxiety, and cardiovascular measures (i.e., blood pressure, heart rate) were recorded during baseline and the conflict discussion. Compared with controls, PTSD couples reported greater couple conflict and less warmth, and displayed pronounced increases in anger and greater increases in systolic blood pressure in response to the conflict task (all ps conflict in veterans with PTSD and their partners. PTSD was associated with greater frequency and severity of couple conflict, and greater anger and cardiovascular reactivity to conflict discussions. Anger and physiological responses to couple discord might contribute to CHD risk in veterans with PTSD, and perhaps their partners, as well. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  7. Magnetic phase transitions and hydrostatic pressure or uniaxial stress experiments

    International Nuclear Information System (INIS)

    Bloch, D.

    1980-01-01

    Crystals submitted to high hydrostatic pressure or uniaxial stress have been investigated by means of neutron scattering. The techniques used are described and applications to pressure or stress induced T = 0 magnetic to nonmagnetic transitions (Pr,PrSb) and continuous to discontinuous order-disorder transitions (MnO) are given. (orig.)

  8. Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianfeng, E-mail: zhoujianfeng@njtech.edu.cn [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Mo, Jingwen [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Shao, Chunlei [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Li, Zhigang [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2015-09-01

    In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress.

  9. Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

    International Nuclear Information System (INIS)

    Zhou, Jianfeng; Mo, Jingwen; Shao, Chunlei; Li, Zhigang

    2015-01-01

    In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress

  10. Effect of Flavonoids on Oxidative Stress and Inflammation in Adults at Risk of Cardiovascular Disease: A Systematic Review

    OpenAIRE

    Jenni Suen; Jolene Thomas; Amelia Kranz; Simon Vun; Michelle Miller

    2016-01-01

    Oxidative stress (OS) and inflammatory processes initiate the first stage of cardiovascular disease (CVD). Flavonoid consumption has been related to significantly improved flow-mediated dilation and blood pressure. Antioxidant and anti-inflammatory mechanisms are thought to be involved. The effect of flavonoids on markers of oxidative stress and inflammation, in at risk individuals is yet to be reviewed. Systematic literature searches were conducted in MEDLINE, Cochrane Library, CINAHL and SC...

  11. Cardiovascular reactivity to a marital conflict version of the Trier social stress test in intimate partner violence perpetrators.

    Science.gov (United States)

    Romero-Martínez, Angel; Nunes-Costa, Rui; Lila, Marisol; González-Bono, Esperanza; Moya-Albiol, Luis

    2014-07-01

    Intimate partner violence (IPV) perpetrators have been categorized into two groups based on their heart rate (HR) reactivity to stress following Gottman's studies. Overall, type I perpetrators tend to show autonomic underarousal, whereas type II or reactive perpetrators present a hyper-reactivity in anticipation of stress. In this study, changes in HR, pre-ejection period (PEP), vagal ratio as well as psychological state variables (anxiety and anger) in response to stress were assessed, comparing a group of type II IPV perpetrators (based on violence reports and psychological assessment; n = 17; mean age = 37) with non-violent controls (n = 17; mean age = 35) using modified version of the Trier Social Stress Test. IPV perpetrators had higher HRs and lower vagal ratios than controls, particularly during the recovery period. Moreover, the former presented shorter PEPs than controls. There were no differences between groups in the magnitude of response of the HR, PEP or vagal ratio. High baseline anxiety and anger were associated with an HR increase during the preparation time in IPV perpetrators but not in controls. These findings indicate a different cardiovascular pattern of response to psychosocial stress in IPV perpetrators, especially during recovery. Thus, they contribute to understanding the biological functioning of violence sub-types, supporting the validity of cardiovascular measures as diagnostic indicators for IPV classification.

  12. Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents

    OpenAIRE

    Eisenmann, Eric D.; Rorabaugh, Boyd R.; Zoladz, Phillip R.

    2016-01-01

    Cardiovascular disease is the largest cause of mortality worldwide, and stress is a significant contributor to the development of cardiovascular disease. The relationship between acute and chronic stress and cardiovascular disease is well-evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury. Conversely, chronic stress is arrythmogenic and incr...

  13. Efeitos de variáveis psicológicas na reatividade cardiovascular em momentos de stress emocional

    OpenAIRE

    Lipp,Marilda Emmanuel Novaes; Frare,Adriana; Santos,Flavia Urbino dos

    2007-01-01

    A influência de características psicológicas no aumento da pressão arterial tem sido objeto de muitas indagações. Este trabalho analisou como, em momentos de stress, a reatividade cardiovascular é afetada por fatores psicológicos. Oitenta hipertensos responderam ao Inventario de Sintomas de Stress de Lipp, à Escala de Alexitimia de Toronto e ao Questionário de Assertividade, e passaram por uma sessão experimental envolvendo interações sociais estressantes. A pressão arterial e a freqüência ca...

  14. Assessment of coronary artery disease with nicorandil stress magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kawase, Yoshio; Nichimoto, Masaki; Hato, Katsunori; Okajima, Kazue; Yoshikawa, Junichi

    2004-01-01

    Although dipyridamole and adenosine have been used as vasodilator agents, we believe they are inadequate for vasodilator perfusion magnetic resonance imaging, due to adverse effects (flushing, warmth, headaches, and arrhythmia). Nicorandil, a potassium channel opener, has been reported to increase coronary blood flow and it was associated with fewer adverse effects than adenosine or dipiridamole. We set out to investigate whether the coronary artery stenosis could be assessed by nicorandil stress perfusion magnetic resonance imaging. First-pass contrast-enhanced magnetic resonance images of the left ventricle acquired from 50 patients at rest and during intravenous administration of nicorandil using multi-slice turbo field echo with multi shot echo-planar-imaging. Coronary angiography was performed within 1 week. There was no adverse effects during nicorandil stress in any patients. The overall sensitivity and specificity of magnetic resonance imaging in identifying patients with significant stenosis of at least one coronary artery were 93.9% (31 of 33 patients) and 94.1% (16 of 17 patients), respectively. The sensitivity of magnetic resonance imaging for detecting significant stenosis in the left anterior descending artery was 87.5%; the sensitivity in the left circumflex artery was 80%; the sensitivity in the right coronary artery was 92.3%. Similar sensitivities were observed for all 3 vascular regions, indicating that all myocardial segments were visualized with similar image quality. The present study shows that nicorandil stress perfusion magnetic resonance imaging is a safe, feasible technique for assessing coronary artery stenosis severity in a totally-noninvasive manner. (authors)

  15. Design and rationale of the MR-INFORM study: stress perfusion cardiovascular magnetic resonance imaging to guide the management of patients with stable coronary artery disease

    Directory of Open Access Journals (Sweden)

    Hussain Shazia T

    2012-09-01

    Full Text Available Abstract Background In patients with stable coronary artery disease (CAD, decisions regarding revascularisation are primarily driven by the severity and extent of coronary luminal stenoses as determined by invasive coronary angiography. More recently, revascularisation decisions based on invasive fractional flow reserve (FFR have shown improved event free survival. Cardiovascular magnetic resonance (CMR perfusion imaging has been shown to be non-inferior to nuclear perfusion imaging in a multi-centre setting and superior in a single centre trial. In addition, it is similar to invasively determined FFR and therefore has the potential to become the non-invasive test of choice to determine need for revascularisation. Trial design The MR-INFORM study is a prospective, multi-centre, randomised controlled non-inferiority, outcome trial. The objective is to compare the efficacy of two investigative strategies for the management of patients with suspected CAD. Patients presenting with stable angina are randomised into two groups: 1 The FFR-INFORMED group has subsequent management decisions guided by coronary angiography and fractional flow reserve measurements. 2 The MR-INFORMED group has decisions guided by stress perfusion CMR. The primary end-point will be the occurrence of major adverse cardiac events (death, myocardial infarction and repeat revascularisation at one year. Clinical trials.gov identifier NCT01236807. Conclusion MR INFORM will assess whether an initial strategy of CMR perfusion is non-inferior to invasive angiography supplemented by FFR measurements to guide the management of patients with stable coronary artery disease. Non-inferiority of CMR perfusion imaging to the current invasive reference standard (FFR would establish CMR perfusion imaging as an attractive non-invasive alternative to current diagnostic pathways.

  16. Fluorine cardiovascular magnetic resonance angiography in vivo at 1.5 T with perfluorocarbon nanoparticle contrast agents.

    Science.gov (United States)

    Neubauer, Anne M; Caruthers, Shelton D; Hockett, Franklin D; Cyrus, Tillman; Robertson, J David; Allen, J Stacy; Williams, Todd D; Fuhrhop, Ralph W; Lanza, Gregory M; Wickline, Samuel A

    2007-01-01

    While the current gold standard for coronary imaging is X-ray angiography, evidence is accumulating that it may not be the most sensitive technique for detecting unstable plaque. Other imaging modalities, such as cardiovascular magnetic resonance (CMR), can be used for plaque characterization, but suffer from long scan and reconstruction times for determining regions of stenosis. We have developed an intravascular fluorinated contrast agent that can be used for angiography with cardiovascular magnetic resosnace at clinical field strengths (1.5 T). This liquid perfluorocarbon nanoparticle contains a high concentration of fluorine atoms that can be used to generate contrast on 19F MR images without any competing background signal from surrounding tissues. By using a perfluorocarbon with 20 equivalent fluorine molecules, custom-built RF coils, a modified clinical scanner, and an efficient steady-state free procession sequence, we demonstrate the use of this agent for angiography of small vessels in vitro, ex vivo, and in vivo. The surprisingly high signal generated with very short scan times and low doses of perfluorocarbon indicates that this technique may be useful in clinical settings when coupled with advanced imaging strategies.

  17. Buoyancy limits on magnetic viscosity stress-law scalings in quasi stellar object accretion disk models

    International Nuclear Information System (INIS)

    Sakimoto, P.J.

    1985-01-01

    Quasi-Stellar Objects (QSOs) are apparently the excessively bright nuclei of distant galaxies. They are thought to be powered by accretion disks surrounding supermassive black holes: however, proof of this presumption is hampered by major uncertainties in the viscous stress necessary for accretion to occur. Models generally assume an and hoc stress law which scales the stress with the total pressure. Near the black hole, radiation pressure dominates gas pressure; scaling the stress with the radiation pressure results in disk models that are thermally unstable and optically thin. This dissertation shows that a radiation pressure scaling for the stress is not possible if the viscosity is due to turbulent magnetic Maxwell stresses. The argument is one of internal self-consistency. First, four model accretion disks that bound the reasonably expected ranges of viscous stress scalings and vertical structures are constructed. Magnetic flux tubes of various initial field strengths are then placed within these models, nd their buoyancy is modeled numerically. In disks using the radiation pressure stress law scaling, low opacities allow rapid heat flow into the flux tubes: the tubes are extremely buoyant, and magnetic fields strong enough to provide the required stress cannot be retained. If an alternative gas pressure scaling for the stress is assumed, then the disks are optically thick; flux tubes have corresponding lower buoyancy, and magnetic fields strong enough to provide the stress can be retained for dynamically significant time periods

  18. Tuning stress-induced magnetic anisotropy and high frequency properties of FeCo films deposited on different curvature substrates

    International Nuclear Information System (INIS)

    Wang, Z.K.; Feng, E.X.; Liu, Q.F.; Wang, J.B.; Xue, D.S.

    2012-01-01

    It is important to control magnetic anisotropy of ferromagnetic materials. In this work, FeCo thin films are deposited on the curving substrates by electrochemical deposition to adjust the stress-induced magnetic anisotropy. The compressive stress is produced in the as-deposited films after the substrates are flattened. A simplified theoretical model of ferromagnetic resonance is utilized to measure the intrinsic magnetic anisotropy field and saturation magnetization. The results show that the stress-induced magnetic anisotropy and the resonance frequency increase with the increase of substrate curvature. The induced easy axis is perpendicular to the compressive stress direction.

  19. Predictors of ischaemic mitral regurgitation recurrence in patients undergoing combined surgery: additional value of cardiovascular magnetic resonance imaging.

    Science.gov (United States)

    Glaveckaite, Sigita; Uzdavinyte-Gateliene, Egle; Petrulioniene, Zaneta; Palionis, Darius; Valeviciene, Nomeda; Kalinauskas, Gintaras; Serpytis, Pranas; Laucevicius, Aleksandras

    2018-03-09

    We aimed to evaluate (i) the effectiveness of combined surgery (coronary artery bypass grafting with restrictive mitral valve annuloplasty) and (ii) the late gadolinium enhancement cardiovascular magnetic resonance-based predictors of ischaemic mitral regurgitation (IMR) recurrence. The prospective analysis included 40 patients with multivessel coronary artery disease, IMR >II° and left ventricular (LV) dysfunction undergoing combined surgery. The degree of IMR and LV parameters were assessed preoperatively by transthoracic echocardiography, 3D transoesophageal echocardiography and cardiovascular magnetic resonance and postoperatively by transthoracic echocardiography. The effective mitral valve repair group (n = 30) was defined as having recurrent ischaemic mitral regurgitation (RIMR) ≤II° at the end of follow-up (25 ± 11 months). The surgery was effective: freedom from RIMR >II° at 1 and 2 years after surgery was 80% and 75%, respectively. Using multivariable logistic regression, 2 independent predictors of RIMR >II° were identified: ≥3 non-viable LV segments (odds ratio 22, P = 0.027) and ≥1 non-viable segment in the LV posterior wall (odds ratio 11, P = 0.026). Using classification trees, the best combinations of cardiovascular magnetic resonance-based and 3D transoesophageal echocardiography-based predictors for RIMR >II° were (i) posterior mitral valve leaflet angle >40° and LV end-systolic volume index >45 ml/m2 (sensitivity 100%, specificity 89%) and (ii) scar transmurality >68% in the inferior LV wall and EuroSCORE II >8 (sensitivity 83%, specificity 78%). There is a clear relationship between the amount of non-viable LV segments, especially in the LV posterior and inferior walls, and the recurrence of IMR after the combined surgery.

  20. Oxidative Stress and Cardiovascular Risk: Obesity, Diabetes, Smoking, and Pollution: Part 3 of a 3-Part Series.

    Science.gov (United States)

    Niemann, Bernd; Rohrbach, Susanne; Miller, Mark R; Newby, David E; Fuster, Valentin; Kovacic, Jason C

    2017-07-11

    Oxidative stress occurs whenever the release of reactive oxygen species (ROS) exceeds endogenous antioxidant capacity. In this paper, we review the specific role of several cardiovascular risk factors in promoting oxidative stress: diabetes, obesity, smoking, and excessive pollution. Specifically, the risk of developing heart failure is higher in patients with diabetes or obesity, even with optimal medical treatment, and the increased release of ROS from cardiac mitochondria and other sources likely contributes to the development of cardiac dysfunction in this setting. Here, we explore the role of different ROS sources arising in obesity and diabetes, and the effect of excessive ROS production on the development of cardiac lipotoxicity. In parallel, contaminants in the air that we breathe pose a significant threat to human health. This paper provides an overview of cigarette smoke and urban air pollution, considering how their composition and biological effects have detrimental effects on cardiovascular health. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  1. Comparison of Heat and Cold Stress Effects on Cardiovascular Mortality and Morbidity in Central European Urban and Rural Populations

    Czech Academy of Sciences Publication Activity Database

    Kyncl, J.; Urban, Aleš; Kyselý, Jan; Davídkovová, Hana; Kříž, B.

    2015-01-01

    Roč. 44 (2015), s. 86 ISSN 0300-5771. [IEA World Congress of Epidemiology (WCE) /20./. 17.08.2014-21.08.2014, Anchorage] R&D Projects: GA ČR(CZ) GAP209/11/1985 Institutional support: RVO:68378289 Keywords : heat stress * cold stress * Central Europe * cardiovascular mortality and morbidity Subject RIV: DG - Athmosphere Sciences, Meteorology https://wce.confex.com/wce/2014/webprogram/Paper1480.html

  2. Cardiovascular fluid dynamics. Methods for flow and pressure field analysis from magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ebbers, T.

    2001-01-01

    Cardiovascular blood flow is highly complex and incompletely understood. Blood flow patterns are expected to influence the opening and closing of normal and prosthetic heart valves, the efficiency of cardiac filling and ejection, and the resistance to thrombus formation within the heart. Conventional diagnostic techniques are poorly suited to the study of the three-dimensional (3D) blood flow patterns in the heart chambers and large vessels. Noninvasive methods have also been inadequate in studying intracardiac pressure differences, which are the driving force of flow and are critical in the evaluation of many cardiovascular abnormalities. This thesis focuses on the development of non-invasive methods for analysis of 3D cardiovascular blood flow. Simultaneous study of cardiovascular fluid dynamics allowed knowledge exchange across the two disciplines, facilitating the development process and broadening the applicability of the methods. A time-resolved 3D phase-contrast Magnetic Resonance Imaging (MRI) technique was used to acquire the velocity vector field in a 3D volume encompassing the entire heart or a large vessel. Cardiovascular blood flow patterns were visualized by use of particle traces, which revealed, for instance, vortical flow patterns in the left atrium. By applying the Navier-Stokes equation along a user-defined line in the 3D velocity vector field, the relative pressure could be obtained as an excellent supplement to the flow pattern visualization. Using a delineation of the blood pool, the time-varying 3D relative pressure field in the human left ventricle was obtained from the velocity field by use of the pressure Poisson equation. A delineation of the heart muscle, a task that is almost impossible to perform on 3D MRI either automatically or manually, was also achieved by usage of particle traces. This segmentation allows automatic calculation of the 3D relative pressure field, as well as calculation of well-established parameters such as

  3. Cardiovascular fluid dynamics. Methods for flow and pressure field analysis from magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ebbers, T

    2001-05-01

    Cardiovascular blood flow is highly complex and incompletely understood. Blood flow patterns are expected to influence the opening and closing of normal and prosthetic heart valves, the efficiency of cardiac filling and ejection, and the resistance to thrombus formation within the heart. Conventional diagnostic techniques are poorly suited to the study of the three-dimensional (3D) blood flow patterns in the heart chambers and large vessels. Noninvasive methods have also been inadequate in studying intracardiac pressure differences, which are the driving force of flow and are critical in the evaluation of many cardiovascular abnormalities. This thesis focuses on the development of non-invasive methods for analysis of 3D cardiovascular blood flow. Simultaneous study of cardiovascular fluid dynamics allowed knowledge exchange across the two disciplines, facilitating the development process and broadening the applicability of the methods. A time-resolved 3D phase-contrast Magnetic Resonance Imaging (MRI) technique was used to acquire the velocity vector field in a 3D volume encompassing the entire heart or a large vessel. Cardiovascular blood flow patterns were visualized by use of particle traces, which revealed, for instance, vortical flow patterns in the left atrium. By applying the Navier-Stokes equation along a user-defined line in the 3D velocity vector field, the relative pressure could be obtained as an excellent supplement to the flow pattern visualization. Using a delineation of the blood pool, the time-varying 3D relative pressure field in the human left ventricle was obtained from the velocity field by use of the pressure Poisson equation. A delineation of the heart muscle, a task that is almost impossible to perform on 3D MRI either automatically or manually, was also achieved by usage of particle traces. This segmentation allows automatic calculation of the 3D relative pressure field, as well as calculation of well-established parameters such as

  4. Whole body cardiovascular magnetic resonance imaging to stratify symptomatic and asymptomatic atherosclerotic burden in patients with isolated cardiovascular disease

    International Nuclear Information System (INIS)

    Weir-McCall, Jonathan R.; Duce, Suzanne L.; Gandy, Stephen J.; Matthew, Shona Z.; Martin, Patricia; Cassidy, Deirdre B.; McCormick, Lynne; Belch, Jill J. F.; Struthers, Allan D.; Colhoun, Helen M.; Houston, J. Graeme

    2016-01-01

    The aim of this study was to use whole body cardiovascular magnetic resonance imaging (WB CVMR) to assess the heart and arterial network in a single examination, so as to describe the burden of atherosclerosis and subclinical disease in participants with symptomatic single site vascular disease. 64 patients with a history of symptomatic single site vascular disease (38 coronary artery disease (CAD), 9 cerebrovascular disease, 17 peripheral arterial disease (PAD)) underwent whole body angiogram and cardiac MR in a 3 T scanner. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cine and late gadolinium enhancement images of the left ventricle were obtained. Asymptomatic atherosclerotic disease with greater than 50 % stenosis in arteries other than that responsible for their presenting complain was detected in 37 % of CAD, 33 % of cerebrovascular and 47 % of PAD patients. Unrecognised myocardial infarcts were observed in 29 % of PAD patients. SAS was significantly higher in PAD patients 24 (17.5-30.5) compared to CAD 4 (2–11.25) or cerebrovascular disease patients 6 (2-10) (ANCOVA p < 0.001). Standardised atheroma score positively correlated with age (β 0.36 p = 0.002), smoking status (β 0.34 p = 0.002), and LV mass (β -0.61 p = 0.001) on multiple linear regression. WB CVMR is an effective method for the stratification of cardiovascular disease. The high prevalence of asymptomatic arterial disease, and silent myocardial infarctions, particularly in the peripheral arterial disease group, demonstrates the importance of a systematic approach to the assessment of cardiovascular disease

  5. Tailoring of magnetoimpedance effect and magnetic softness of Fe-rich glass-coated microwires by stress- annealing.

    Science.gov (United States)

    Zhukova, V; Blanco, J M; Ipatov, M; Churyukanova, M; Taskaev, S; Zhukov, A

    2018-02-16

    There is a pressing need for improving of the high-frequency magneto-impedance effect of cost-effective soft magnetic materials for use in high-performance sensing devices. The impact of the stress-annealing on magnetic properties and high frequency impedance of Fe-rich glass-coated microwires was studied. Hysteresis loops of Fe-rich microwires have been considerably affected by stress- annealing. In stress-annealed Fe- rich microwire we obtained drastic decreasing of coercivity and change of character of hysteresis loop from rectangular to linear. By controlling stress-annealing conditions (temperature and time) we achieved drastic increasing (by order of magnitude) of giant magnetoimpedance ratio. Coercivity, remanent magnetization, diagonal and of-diagonal magnetoimpedance effect of Fe-rich microwires can be tuned by stress-annealing conditions: annealing temperature and time. Observed experimental results are discussed considering relaxation of internal stresses, compressive "back-stresses" arising after stress annealing and topological short range ordering.

  6. Effect of atropine or atenolol on cardiovascular responses to novelty stress in freely-moving rats.

    Science.gov (United States)

    van den Buuse, Maarten

    2002-09-01

    Cardiac hemodynamic mechanisms involved in cardiovascular responses to stress were studied in conscious, freely-moving female spontaneously hypertensive rats exposed for 15 min to an open-field. When pretreated with saline, the rats displayed a rapid rise in blood pressure, heart rate, aortic dP/dt and locomotor activity. In rats pretreated with 0.5 mg/kg of methylatropine, the tachycardia was slightly, but significantly reduced. In rats pretreated with 1 mg/kg of atenolol, the tachycardis and rise in dP/dt were markedly reduced. These data suggest that the cardiac responses to stress include predominantly cardiac sympathetic activation and a minor component of vagal withdrawal.

  7. Stress analysis, structure and magnetic properties of sputter deposited Ni-Mn-Ga ferromagnetic shape memory thin films

    Energy Technology Data Exchange (ETDEWEB)

    Annadurai, A. [Department of Physics, PSG College of Technology, Coimbatore 641004 (India); Manivel Raja, M., E-mail: mraja@dmrl.drdo.in [Defense Metallurgical Research Laboratory, Hyderabad 500058 (India); Prabahar, K.; Kumar, Atul [Defense Metallurgical Research Laboratory, Hyderabad 500058 (India); Kannan, M.D.; Jayakumar, S. [Department of Physics, PSG College of Technology, Coimbatore 641004 (India)

    2011-11-15

    The residual stress instituted in Ni-Mn-Ga thin films during deposition is a key parameter influencing their shape memory applications by affecting its structural and magnetic properties. A series of Ni-Mn-Ga thin films were prepared by dc magnetron sputtering on Si(1 0 0) and glass substrates at four different sputtering powers of 25, 45, 75 and 100 W for systematic investigation of the residual stress and its effect on structure and magnetic properties. The residual stresses in thin films were characterized by a laser scanning technique. The as-deposited films were annealed at 600 deg. C for 1 h in vacuum for structural and magnetic ordering. The compressive stresses observed in as-deposited films transformed into tensile stresses upon annealing. The annealed films were found to be crystalline and possess mixed phases of both austenite and martensite, exhibiting good soft magnetic properties. It was found that the increase of sputtering power induced coarsening in thin films. Typical saturation magnetization and coercivity values were found to be 330 emu/cm{sup 3} and 215 Oe, respectively. The films deposited at 75 and 100 W display both structural and magnetic transitions above room temperature. - Highlights: > Compressive stresses observed in as-deposited films transformed into tensile stresses upon annealing. > Annealed films were found to be crystalline and possess mixed phases of both austenite and martensite, exhibiting good soft magnetic properties. > The highest Curie transition in the films was observed at 365 K. > The films deposited at 75 and 100 W display both structural and magnetic transitions above room temperature.

  8. Feasibility study of determining axial stress in ferromagnetic bars using reciprocal amplitude of initial differential susceptibility obtained from static magnetization by permanent magnets

    Science.gov (United States)

    Deng, Dongge; Wu, Xinjun

    2018-03-01

    An electromagnetic method for determining axial stress in ferromagnetic bars is proposed. In this method, the tested bar is under the static magnetization provided by permanent magnets. The tested bar do not have to be magnetized up to the technical saturation because reciprocal amplitude of initial differential susceptibility (RAIDS) is adopted as the feature parameter. RAIDS is calculated from the radial magnetic flux density Br Lo = 0.5 at the Lift-off Lo = 0.5 mm, radial magnetic flux density Br Lo = 1 at the Lift-off Lo = 1 mm and axial magnetic flux density Bz Lo = 1 at the Lift-off Lo = 1 mm from the surface of the tested bar. Firstly, the theoretical derivation of RAIDS is carried out according to Gauss' law for magnetism, Ampere's Law and the Rayleigh relation in Rayleigh region. Secondly, the experimental system is set up for a 2-meter length and 20 mm diameter steel bar. Thirdly, an experiment is carried out on the steel bar to analyze the relationship between the obtained RAIDS and the axial stress. Experimental results show that the obtained RAIDS decreases almost linearly with the increment of the axial stress inside the steel bar in the initial elastic region. The proposed method has the potential to determine tensile axial stress in the slender cylindrical ferromagnetic bar.

  9. Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.

    Science.gov (United States)

    Klein-Wiele, Oliver; Garmer, Marietta; Urbien, Rhyan; Busch, Martin; Kara, Kaffer; Mateiescu, Serban; Grönemeyer, Dietrich; Schulte-Hermes, Michael; Garbrecht, Marc; Hailer, Birgit

    2015-12-22

    Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine. We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

  10. Self-esteem, performance feedback, and cardiovascular stress reactivity.

    Science.gov (United States)

    Hughes, Brian M

    2007-09-01

    This study sought to establish the impact of performance-related feedback on cardiovascular responses to stressors, and whether this impact is influenced by individual differences in self-esteem. A total of 66 college women were categorized as either high or low in self-esteem on the basis of their scores in a standardized psychometric test. They then took part in a laboratory experiment, in which they were assigned to one of three performance-feedback manipulations. Following the provision of feedback on an initial laboratory task (picture-matching), they undertook a second task (mental arithmetic). Cardiovascular functioning was monitored throughout. Provision of negative feedback to the initial task exerted an adverse impact on cardiovascular responses, suggestive of unhappiness with performance. Provision of positive feedback to the initial task exerted an impact on cardiovascular functioning during the second task, suggestive of task engagement. Importantly, low self-esteem exacerbated the adverse impact of negative feedback. The impact of feedback and the buffering role of self-esteem may have important consequences for cardiovascular health. Further, discrepancies in the findings of previous feedback research may be accounted for by dispositional individual differences.

  11. Acute stress decreases but chronic stress increases myocardial sensitivity to ischemic injury in rodents

    Directory of Open Access Journals (Sweden)

    Eric D Eisenmann

    2016-04-01

    Full Text Available Cardiovascular disease is the largest cause of mortality worldwide, and stress is a significant contributor to the development of cardiovascular disease. The relationship between acute and chronic stress and cardiovascular disease is well-evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury. Conversely, chronic stress is arrythmogenic and increases sensitivity to myocardial ischemia-reperfusion injury. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions.

  12. The psychoemotional status and cardiovascular system functional state of the first-year students under the influence of examination stress

    Directory of Open Access Journals (Sweden)

    Liliana K. Tokaeva

    2012-12-01

    Full Text Available The aim of this research is to study of the influence of examination stress on psycho-emotional status and functional state of the cardiovascular system of the 1-st year students of pedagogical high school. Methods – The study involved 105 young men aged 17-18 enrolled in the specialty "Physical Education". The studies were conducted during the period in-between the exams and during the examination session. The psycho-emotional status was determined by the SAN test questionnaire and test and the CH.D. Spielberg test, adapted for Russia by Ju.L. Khanin. The state of CVS autonomic regulation was evaluated by heart rate, blood pressure, endurance ratio, Kerdo index and the adaptive capacities by P.M. Bayevsky. Results – In the absence of exposure to stress in the majority of young men the studied parameters are within normal limits, indicating sufficient adaptive capabilities. A clear correlation between the level of personal anxiety in students and the nature of their reactivity to examination stress was found: the higher the anxiety level in a student is, the more stress resistance decreases and more pronounced changes in the cardiovascular system autonomic regulation appear. The strain of adaptation mechanism was found in a stressful situation in the first-year students with a high level of personal anxiety and satisfactory adaptation – in young men with average and low personal anxiety.

  13. El impacto de la reducción del estrés en la hipertensión esencial y las enfermedades cardiovasculares. (Impact of stress reduction on essential hypertension and cardiovascular disease.

    Directory of Open Access Journals (Sweden)

    David W. Orme-Johnson

    2008-07-01

    Full Text Available ResumenSe ha considerado que el estrés contribuye a la patogénesis y la progresión de las enfermedades cardiovasculares (ECV. Se ha demostrado que la reducción del estrés mediante la Meditación Trascendental [Transcendental Meditation (TM®] ha bajado los niveles de presión arterial (PA y reducido el riesgo de ECV en adultos y adolescentes. Este artículo repasa los resultados que sugieren el impacto beneficioso de la TM en reducir la PA en adultos hipertensos en reposo y en adolescentes pre-hipertensos en reposo, durante un estrés agudo creado en el laboratorio y durante la actividad diaria normal. Dichos resultados tienen implicaciones importantes para la inclusión de la TM en los esfuerzos que se realizan para prevenir y tratar las ECV y sus consecuencias clínicas.AbstractStress has been thought to contribute to the pathogenesis and progression of cardiovascular diseases (CVD. Stress reduction via Trasncendental Meditation (TM® has been shown to lower blood pressure (BP levels and reduce CVD risk in adults and adolescents. This article reviews findings suggesting a beneficial BP-lowering impact of TM in hypertensive adults at rest and in pre-hypertensive adolescents at rest, during acute laboratory stress and during normal daily activity. These findings have important implications for inclusion of TM efforts to prevent and treat cardiovascular diseases and their clinical consequences.

  14. Deficits in water maze performance and oxidative stress in the hippocampus and striatum induced by extremely low frequency magnetic field exposure.

    Directory of Open Access Journals (Sweden)

    Yonghua Cui

    Full Text Available The exposures to extremely low frequency magnetic field (ELF-MF in our environment have dramatically increased. Epidemiological studies suggest that there is a possible association between ELF-MF exposure and increased risks of cardiovascular disease, cancers and neurodegenerative disorders. Animal studies show that ELF-MF exposure may interfere with the activity of brain cells, generate behavioral and cognitive disturbances, and produce deficits in attention, perception and spatial learning. Although, many research efforts have been focused on the interaction between ELF-MF exposure and the central nervous system, the mechanism of interaction is still unknown. In this study, we examined the effects of ELF-MF exposure on learning in mice using two water maze tasks and on some parameters indicative of oxidative stress in the hippocampus and striatum. We found that ELF-MF exposure (1 mT, 50 Hz induced serious oxidative stress in the hippocampus and striatum and impaired hippocampal-dependent spatial learning and striatum-dependent habit learning. This study provides evidence for the association between the impairment of learning and the oxidative stress in hippocampus and striatum induced by ELF-MF exposure.

  15. Stress relaxation technique of high magnetic field superconducting magnet for the nuclear fusion

    International Nuclear Information System (INIS)

    Kamimoto, Masayuki; Tateishi, Hiroshi; Agatsuma, Ko; Arai, Kazuaki; Umeda, Masaichi

    1999-01-01

    Here were attempted not only to prove effectiveness of a stress self-supporting type wire material for magnet constituting technique, but also to develop a fiber reinforcing type superconducting wire material used by materials with excellent strain resistance to expand usable range of the stress self-supporting type with material. In 1997 fiscal year, superconductive features of the wire material produced by using composite processing method were evaluated, actual applicability for superconducting wire material was inspected, and investigation on manufacturing parameter of NbN thin films on trial production at present apparatus was conducted. (G.K.)

  16. Effects of spacer layer on growth, stress and magnetic properties of sputtered permalloy film

    International Nuclear Information System (INIS)

    Cheng, S.F.; Lubitz, P.; Zheng, Y.; Edelstein, A.S.

    2004-01-01

    A microelectromechanical (MEMS) flux concentrator (J. Appl. phys. 91 (2002) 7795), is a device that will minimize 1/f noise in magnetic sensors by modulating the magnetic field at the position of the sensor. This requires high permeability and low stress permalloy (Py) films to be deposited on the MEMS flaps (J. Appl. phys. 91 (2002) 7795). Py (Ni 80 Fe 20 ) films from 100 to 560 nm thick were deposited on Si substrates using DC magnetron sputtering. The effects of deposition conditions on the grain morphology, texture, stress and magnetic properties were studied. Lower sputtering pressure changes film stress from tension to compression and increases the out of film plane texture, while higher power increases tension and texture. Neutral film stress was obtained with 100 W of sputtering power and 1.25 mTorr of Ar gas pressure. With increasing thickness, the Py film was found to develop a stripe-like domain configuration at low fields because of strong out-of-plane magnetic anisotropy. The critical thickness is around 180 nm.This may be explained by a competition between planar demagnetization fields and columnar magnetic anisotropy. Adding 5 nm of Ta or Cr layer as spacer successfully broke up the continuity of the magnetic structure and allowed us to produce high-permeability films by fabricating (Ta/Py) or (Cr/Py) multilayer films with each Py layer thinner than the critical thickness

  17. Cardiovascular magnetic resonance imaging in the assessment of carcinoid heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Sandmann, H.; Pakkal, M. [Queen Elizabeth Hospital, Birmingham (United Kingdom); Steeds, R. [Queen Elizabeth Hospital, Birmingham (United Kingdom)], E-mail: rick.steeds@uhb.nhs.uk

    2009-08-15

    Carcinoid disease arises from a low-grade neuroendocrine tumour derived from serotonin-producing enterochromaffin cells. It is the most common tumour affecting the small bowel. The majority of patients who progress to carcinoid syndrome develop cardiac disease selectively involving the right side of the heart, whereas left heart disease is unusual. The most common cause of death is dilatation and dysfunction of the right ventricle. Right ventricular dysfunction is largely secondary to pathological endocardial fibrosis of the tricuspid and pulmonary valves, presenting with regurgitation and stenosis. Average survival falls to only 11 months with the onset of symptoms, but recent evidence suggests that survival can be improved by early surgery in selected individuals. This article reviews the particular role that cardiovascular magnetic resonance imaging has in the management of carcinoid heart disease.

  18. The association between changes in pressure pain sensitivity and changes in cardiovascular physiological factors associated with persistent stress

    DEFF Research Database (Denmark)

    Ballegaard, Søren; Petersen, Pernille B.; Harboe, Gitte S.

    2014-01-01

    Abstract Objectives. To evaluate the possible association between pressure pain sensitivity of the chest bone (PPS) and cardiovascular physiological factors related to persistent stress in connection with a three-month PPS-guided stress-reducing experimental intervention programme. Methods. Forty......-two office workers with an elevated PPS (≥ 60 arbitrary units) as a sign of increased level of persistent stress, completed a single-blinded cluster randomized controlled trial. The active treatment was a PPS (self-measurement)-guided stress management programme. Primary endpoints: Blood pressure (BP), heart...... between-group reductions were observed in respect to BP, HR, PRP, total and LDL cholesterol, and total number of elevated risk factors (p stress intervention method applied in this study induced a decrease in PPS which was associated with a clinically relevant decrease in resting...

  19. Effect of loading speed on the stress-induced magnetic behavior of ferromagnetic steel

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Sheng, E-mail: longtubao@zju.edu.cn; Gu, Yibin; Fu, Meili; Zhang, Da; Hu, Shengnan

    2017-02-01

    The primary goal of this research is to investigate the effect of loading speed on the stress-induced magnetic behavior of a ferromagnetic steel. Uniaxial tension tests on Q235 steel were carried out with various stress levels under different loading speeds. The variation of the magnetic signals surrounding the tested specimen was detected by a fluxgate magnetometer. The results indicated that the magnetic signal variations depended not only on the tensile load level but on the loading speed during the test. The magnetic field amplitude seemed to decrease gradually with the increase in loading speed at the same tensile load level. Furthermore, the evolution of the magnetic reversals is also related to the loading speed. Accordingly, the loading speed should be considered as one of the influencing variables in the Jies-Atherton model theory of the magnetomechanical effect. - Highlights: • Magnetic behaviors induced by different loading speeds were investigated. • Loading speed imposes strong impact on the variation of the magnetic field signals. • The magnetic field amplitude reduces gradually with the increasing loading speed. • The Jies-Atherton model theory should consider the effect of loading speed.

  20. Effect of loading speed on the stress-induced magnetic behavior of ferromagnetic steel

    International Nuclear Information System (INIS)

    Bao, Sheng; Gu, Yibin; Fu, Meili; Zhang, Da; Hu, Shengnan

    2017-01-01

    The primary goal of this research is to investigate the effect of loading speed on the stress-induced magnetic behavior of a ferromagnetic steel. Uniaxial tension tests on Q235 steel were carried out with various stress levels under different loading speeds. The variation of the magnetic signals surrounding the tested specimen was detected by a fluxgate magnetometer. The results indicated that the magnetic signal variations depended not only on the tensile load level but on the loading speed during the test. The magnetic field amplitude seemed to decrease gradually with the increase in loading speed at the same tensile load level. Furthermore, the evolution of the magnetic reversals is also related to the loading speed. Accordingly, the loading speed should be considered as one of the influencing variables in the Jies-Atherton model theory of the magnetomechanical effect. - Highlights: • Magnetic behaviors induced by different loading speeds were investigated. • Loading speed imposes strong impact on the variation of the magnetic field signals. • The magnetic field amplitude reduces gradually with the increasing loading speed. • The Jies-Atherton model theory should consider the effect of loading speed.

  1. Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings

    Science.gov (United States)

    Stegemann, Robert; Cabeza, Sandra; Lyamkin, Viktor; Bruno, Giovanni; Pittner, Andreas; Wimpory, Robert; Boin, Mirko; Kreutzbruck, Marc

    2017-03-01

    The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction (ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth.

  2. Machine learning based analysis of cardiovascular images

    NARCIS (Netherlands)

    Wolterink, JM

    2017-01-01

    Cardiovascular diseases (CVDs), including coronary artery disease (CAD) and congenital heart disease (CHD) are the global leading cause of death. Computed tomography (CT) and magnetic resonance imaging (MRI) allow non-invasive imaging of cardiovascular structures. This thesis presents machine

  3. Cardiovascular involvement in myositis

    DEFF Research Database (Denmark)

    Diederichsen, Louise P

    2017-01-01

    PURPOSE OF REVIEW: The purpose of this review is to provide an update on cardiovascular involvement in idiopathic inflammatory myopathy (IIM). Studies from the past 18 months are identified and reviewed. Finally, the clinical impact of these findings is discussed. RECENT FINDINGS: Epidemiological...... on cardiac magnetic resonance (CMR) imaging suggests that CMR should be considered as a potentially viable diagnostic tool to evaluate the possibility of silent myocardial inflammation in IIM with normal routine noninvasive evaluation. SUMMARY: Updated literature on cardiovascular involvement in IIM has...... identified an increased risk for subclinical and clinical cardiovascular disease in these rare inflammatory muscle diseases....

  4. Value of black blood T2* cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Carpenter John Paul

    2011-03-01

    Full Text Available Abstract Purpose To assess whether black blood T2* cardiovascular magnetic resonance is superior to conventional white blood imaging of cardiac iron in patients with thalassaemia major (TM. Materials and methods We performed both conventional white blood and black blood T2* CMR sequences in 100 TM patients to determine intra and inter-observer variability and presence of artefacts. In 23 patients, 2 separate studies of both techniques were performed to assess interstudy reproducibility. Results Cardiac T2* values ranged from 4.5 to 43.8 ms. The mean T2* values were not different between black blood and white blood acquisitions (20.5 vs 21.6 ms, p = 0.26. Compared with the conventional white blood diastolic acquisition, the coefficient of variance of the black blood CMR technique was superior for intra-observer reproducibility (1.47% vs 4.23%, p Conclusions Black blood T2* CMR has superior reproducibility and reduced imaging artefacts for the assessment of cardiac iron, in comparison with the conventional white blood technique, which make it the preferred technique for clinical practice.

  5. Can cardiovascular magnetic resonance prompt early cardiovascular/rheumatic treatment in autoimmune rheumatic diseases? Current practice and future perspectives.

    Science.gov (United States)

    Mavrogeni, Sophie I; Sfikakis, Petros P; Dimitroulas, Theodoros; Koutsogeorgopoulou, Loukia; Katsifis, Gikas; Markousis-Mavrogenis, George; Kolovou, Genovefa; Kitas, George D

    2018-06-01

    Life expectancy in autoimmune rheumatic diseases (ARDs) remains lower compared to the general population, due to various comoborbidities. Cardiovascular disease (CVD) represents the main contributor to premature mortality. Conventional and biologic disease-modifying antirheumatic drugs (DMARDs) have considerably improved long-term outcomes in ARDs not only by suppressing systemic inflammation but also by lowering CVD burden. Regarding atherosclerotic disease prevention, EULAR has recommended tight disease control accompanied by regular assessment of traditional CVD risk factors and lifestyle changes. However, this approach, although rational and evidence-based, does not account for important issues such as myocardial inflammation and the long asymptomatic period that usually proceeds clinical manifestations of CVD disease in ARDs before or after the diagnosis of systemic disease. Cardiovascular magnetic resonance (CMR) can offer reliable, reproducible and operator independent information regarding myocardial inflammation, ischemia and fibrosis. Some studies suggest a role for CMR in the risk stratification of ARDs and demonstrate that oedema/fibrosis visualisation with CMR may have the potential to inform cardiac and rheumatic treatment modification in ARDs with or without abnormal routine cardiac evaluation. In this review, we discuss how CMR findings could influence anti-rheumatic treatment decisions targeting optimal control of both systemic and myocardial inflammation irrespective of clinical manifestations of cardiac disease. CMR can provide a different approach that is very promising for risk stratification and treatment modification; however, further studies are needed before the inclusion of CMR in the routine evaluation and treatment of patients with ARDs.

  6. Magnetic resonance imaging (MRI) of congenital cardiovascular malformations

    International Nuclear Information System (INIS)

    Sakakibara, Makoto; Kobayashi, Shirou; Imai, Hitoshi; Watanabe, Shigeru; Masuda, Yoshiaki; Inagaki, Yoshiaki; Morita, Huminori; Uematsu, Sadao; Arimizu, Noboru

    1986-01-01

    In order to determine the value of MRI in diagnosing congenital cardiovascular malformations, MR Images were obtained in 25 adult patients with congenital cardiovascular malformations. Gated MRI detected all of 13 atrial septal defects, and all of 4 ventricular septal defects, but ungated MRI detected none of 3 atrial septal defects. Other congenital cardiovascular malformations (2 with Ebstein's disease, 1 with Fallot's pentalogy, and 1 with Pulmonary stenosis) were well visualized. Vascular malformations (1 with Patent ducts arteriosus, 1 with Supravalvelar aortic stenosis, 1 with Coarctation of Aorta, 1 with Right Aortic Arch) were well visualized in all of 7 patients by ungated MRI. MRI was a valuable noninvasive method of diagnosing congenital heart disease. (author)

  7. Altered cardiovascular reactivity and osmoregulation during hyperosmotic stress in adult rats developmentally exposed to polybrominated diphenyl ethers (PBDEs)

    International Nuclear Information System (INIS)

    Shah, Ashini; Coburn, Cary G.; Watson-Siriboe, Abena; Whitley, Rebecca; Shahidzadeh, Anoush; Gillard, Elizabeth R.; Nichol, Robert; Leon-Olea, Martha; Gaertner, Mark; Kodavanti, Prasada Rao S.; Curras-Collazo, Margarita C.

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) and the structurally similar chemicals polychlorinated biphenyls (PCBs) disrupt the function of multiple endocrine systems. PCBs and PBDEs disrupt the secretion of vasopressin (VP) from the hypothalamus during osmotic activation. Since the peripheral and central vasopressinergic axes are critical for osmotic and cardiovascular regulation, we examined whether perinatal PBDE exposure could impact these functions during physiological activation. Rats were perinatally dosed with a commercial PBDE mixture, DE-71. Dams were given 0 (corn oil control), 1.7 (low dose) or 30.6 mg/kg/day (high dose) in corn oil from gestational day (GD) 6 through postnatal day (PND) 21 by oral gavage. In the male offspring exposed to high dose PBDE plasma thyroxine and triiodothyronine levels were reduced at PND 21 and recovered to control levels by PND 60 when thyroid stimulating hormone levels were elevated. At 14-18 months of age, cardiovascular responses were measured in four groups of rats: Normal (Oil, normosmotic condition), Hyper (Oil, hyperosmotic stress), Hyper PBDE low (1.7 mg/kg/day DE-71 perinatally, hyperosmotic stress), and Hyper PBDE high (30.6 mg/kg/day DE-71 perinatally, hyperosmotic stress). Systolic blood pressure (BP), diastolic BP, and heart rate (HR) were determined using tail cuff sphygmomanometry and normalized to pretreatment values (baseline) measured under basal conditions. Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. Hyper PBDE low and high dose rats showed 36.1 and 64.7% greater systolic BP responses at 3 h post hyperosmotic injection relative to pretreatment baseline, respectively. No treatment effects were measured for diastolic BP and HR. Hyper and Hyper PBDE rats showed increased mean plasma osmolality values by 45 min after injection relative to normosmotic controls. In contrast to Hyper rats, Hyper PBDE (high) rats showed a further increase in mean plasma osmolality at 3

  8. Chemotherapeutic-Induced Cardiovascular Dysfunction: Physiological Effects, Early Detection—The Role of Telomerase to Counteract Mitochondrial Defects and Oxidative Stress

    Science.gov (United States)

    Quryshi, Nabeel; Norwood Toro, Laura E.; Ait-Aissa, Karima; Kong, Amanda; Beyer, Andreas M.

    2018-01-01

    Although chemotherapeutics can be highly effective at targeting malignancies, their ability to trigger cardiovascular morbidity is clinically significant. Chemotherapy can adversely affect cardiovascular physiology, resulting in the development of cardiomyopathy, heart failure and microvascular defects. Specifically, anthracyclines are known to cause an excessive buildup of free radical species and mitochondrial DNA damage (mtDNA) that can lead to oxidative stress-induced cardiovascular apoptosis. Therefore, oncologists and cardiologists maintain a network of communication when dealing with patients during treatment in order to treat and prevent chemotherapy-induced cardiovascular damage; however, there is a need to discover more accurate biomarkers and therapeutics to combat and predict the onset of cardiovascular side effects. Telomerase, originally discovered to promote cellular proliferation, has recently emerged as a potential mechanism to counteract mitochondrial defects and restore healthy mitochondrial vascular phenotypes. This review details mechanisms currently used to assess cardiovascular damage, such as C-reactive protein (CRP) and troponin levels, while also unearthing recently researched biomarkers, including circulating mtDNA, telomere length and telomerase activity. Further, we explore a potential role of telomerase in the mitigation of mitochondrial reactive oxygen species and maintenance of mtDNA integrity. Telomerase activity presents a promising indicator for the early detection and treatment of chemotherapy-derived cardiac damage. PMID:29534446

  9. Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study.

    Science.gov (United States)

    Ohta, Masanori; Eguchi, Yasumasa; Inoue, Tomohiro; Honda, Toru; Morita, Yusaku; Konno, Yoshimasa; Yamato, Hiroshi; Kumashiro, Masaharu

    2015-01-01

    Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n=7) and the control group (n=6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

  10. Heat- and cold-stress effects on cardiovascular mortality and morbidity among urban and rural populations in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Urban, A.; Davídkovová, Hana; Kyselý, J.

    2014-01-01

    Roč. 58, č. 6 (2014), s. 1057-1068 ISSN 0020-7128 Institutional support: RVO:67985530 ; RVO:68378289 Keywords : heat and cold stress * cardiovascular disease * mortality * morbidity * urban and rural differences * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.246, year: 2014

  11. Ultra-small superparamagnetic particles of iron oxide in magnetic resonance imaging of cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Stirrat CG

    2014-10-01

    Full Text Available Colin G Stirrat,1 Alex T Vesey,1 Olivia MB McBride,1 Jennifer MJ Robson,1 Shirjel R Alam,1 William A Wallace,2 Scott I Semple,1,3 Peter A Henriksen,1 David E Newby1 1British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; 2Department of Pathology, University of Edinburgh, Edinburgh, UK; 3Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, UK Abstract: Ultra-small superparamagnetic particles of iron oxide (USPIO are iron-oxide based contrast agents that enhance and complement in vivo magnetic resonance imaging (MRI by shortening T1, T2, and T2* relaxation times. USPIO can be employed to provide immediate blood pool contrast, or to act as subsequent markers of cellular inflammation through uptake by inflammatory cells. They can also be targeted to specific cell-surface markers using antibody or ligand labeling. This review will discuss the application of USPIO contrast in MRI studies of cardiovascular disease. Keywords: cardiac, aortic, MRI, USPIO, carotid, vascular, molecular imaging

  12. Associations of oxidative stress status parameters with traditional cardiovascular disease risk factors in patients with schizophrenia.

    Science.gov (United States)

    Vidović, Bojana; Stefanović, Aleksandra; Milovanović, Srđan; Ðorđević, Brižita; Kotur-Stevuljević, Jelena; Ivanišević, Jasmina; Miljković, Milica; Spasić, Slavica

    2014-04-01

    The purpose of this study was to assess oxidative stress status parameters and their possible associations with traditional cardiovascular risk factors in patients with schizophrenia, as well as their potential for patient-control discrimination. Fasting glucose, lipid profile and oxidative stress status parameters were assessed in 30 schizophrenic patients with atypical antipsychotic therapy and 60 control subjects. Malondialdehyde (MDA), pro-oxidant/antioxidant balance (PAB) and total anti-oxidant status (TAS) were significantly higher whereas total sulfhydryl (SH) groups were significantly lower in schizophrenic patients vs. control group. Higher serum PAB values showed an independent association with schizophrenia. The addition of PAB to conventional risk factors improved discrimination between healthy control subjects and patients. Increased oxidative stress and changed lipid profile parameters are associated in schizophrenic patients and may indicate risk for atherosclerosis. The serum PAB level may reflect the levels of oxidative stress in schizophrenia and improve discrimination of patients from controls.

  13. Effect of the induced magnetic field on peristaltic flow of a couple stress fluid

    International Nuclear Information System (INIS)

    Mekheimer, Kh.S.

    2008-01-01

    We have analyzed the MHD flow of a conducting couple stress fluid in a slit channel with rhythmically contracting walls. In this analysis we are taking into account the induced magnetic field. Analytical expressions for the stream function, the magnetic force function, the axial pressure gradient, the axial induced magnetic field and the distribution of the current density across the channel are obtained using long wavelength approximation. The results for the pressure rise, the frictional force per wave length, the axial induced magnetic field and distribution of the current density across the channel have been computed numerically and the results were studied for various values of the physical parameters of interest, such as the couple stress parameter γ, the Hartmann number M, the magnetic Reynolds number R m and the time averaged mean flow rate θ. Contour plots for the stream and magnetic force functions are obtained and the trapping phenomena for the flow field is discussed

  14. A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress

    DEFF Research Database (Denmark)

    Truijen, Jasper; Bundgaard-Nielsen, Morten; van Lieshout, Johannes J

    2010-01-01

    that a given central blood volume may be associated with markedly different central vascular pressures. The central blood volume varies with posture and, consequently, stroke volume and cardiac output (Q) are affected, but with the increased central blood volume during head-down tilt, stroke volume and Q do...... not increase further indicating that in the supine resting position the heart operates on the plateau of the Frank-Starling curve which, therefore, may be taken as a functional definition of normovolaemia. Since the capacity of the vascular system surpasses the blood volume, orthostatic and environmental...... stress including bed rest/microgravity, exercise and training, thermal loading, illness, and trauma/haemorrhage is likely to restrict venous return and Q. Consequently the cardiovascular responses are determined primarily by their effect on the central blood volume. Thus during environmental stress, flow...

  15. Cardiovascular disease hospitalizations in relation to exposure to the September 11, 2001 World Trade Center disaster and posttraumatic stress disorder.

    Science.gov (United States)

    Jordan, Hannah T; Stellman, Steven D; Morabia, Alfredo; Miller-Archie, Sara A; Alper, Howard; Laskaris, Zoey; Brackbill, Robert M; Cone, James E

    2013-10-24

    A cohort study found that 9/11-related environmental exposures and posttraumatic stress disorder increased self-reported cardiovascular disease risk. We attempted to replicate these findings using objectively defined cardiovascular disease hospitalizations in the same cohort. Data for adult World Trade Center Health Registry enrollees residing in New York State on enrollment and no cardiovascular disease history (n = 46,346) were linked to a New York State hospital discharge-reporting system. Follow-up began at Registry enrollment (2003-2004) and ended at the first cerebrovascular or heart disease (HD) hospitalization, death, or December 31, 2010, whichever was earliest. We used proportional hazards models to estimate adjusted hazard ratios (AHRs) for HD (n = 1151) and cerebrovascular disease (n = 284) hospitalization during 302,742 person-years of observation (mean follow-up, 6.5 years per person), accounting for other factors including age, race/ethnicity, smoking, and diabetes. An elevated risk of HD hospitalization was observed among women (AHR 1.32, 95% CI 1.01 to 1.71) but not men (AHR 1.16, 95% CI 0.97 to 1.40) with posttraumatic stress disorder at enrollment. A high overall level of World Trade Center rescue and recovery-related exposure was associated with an elevated HD hospitalization risk in men (AHR 1.82, 95% CI 1.06 to 3.13; P for trend = 0.05), but findings in women were inconclusive (AHR 3.29, 95% CI 0.85 to 12.69; P for trend = 0.09). Similar associations were observed specifically with coronary artery disease hospitalization. Posttraumatic stress disorder increased the cerebrovascular disease hospitalization risk in men but not in women. 9/11-related exposures and posttraumatic stress disorder appeared to increase the risk of subsequent hospitalization for HD and cerebrovascular disease. This is consistent with findings based on self-reported outcomes.

  16. Measurement and modeling of magnetic hysteresis under field and stress application in iron–gallium alloys

    International Nuclear Information System (INIS)

    Evans, Phillip G.; Dapino, Marcelo J.

    2013-01-01

    Measurements are performed to characterize the hysteresis in magnetomechanical coupling of iron–gallium (Galfenol) alloys. Magnetization and strain of production and research grade Galfenol are measured under applied stress at constant field, applied field at constant stress, and alternately applied field and stress. A high degree of reversibility in the magnetomechanical coupling is demonstrated by comparing a series of applied field at constant stress measurements with a single applied stress at constant field measurement. Accommodation is not evident and magnetic hysteresis for applied field and stress is shown to be coupled. A thermodynamic model is formulated for 3-D magnetization and strain. It employs a stress, field, and direction dependent hysteron that has an instantaneous loss mechanism, similar to Coulomb-friction or Preisach-type models. Stochastic homogenization is utilized to account for the smoothing effect that material inhomogeneities have on bulk processes. - Highlights: ► We conduct coupled experiments and develop nonlinear thermodynamic models for magnetostrictive iron–gallium (Galfenol) alloys. ► The measurements show unexpected kinematic reversibility in the magnetomechanical coupling. ► This is in contrast with the magnetomechanical coupling in steel which is both thermodynamically and kinematically irreversible. ► The model accurately describes the measurements and provides a framework for understanding hysteresis in ferromagnetic materials which exhibit kinematically reversible magnetomechanical coupling.

  17. The histological basis of late gadolinium enhancement cardiovascular magnetic resonance in a patient with Anderson-Fabry disease

    OpenAIRE

    Moon, J. C.; Sheppard, M.; Reed, E.; Lee, P.; Elliott, P. M.; Pennell, D. J.

    2006-01-01

    Anderson-Fabry Disease (AFD) is a storage disease that mimics hypertrophic cardiomyopathy. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance occurs in approximately 50% of patients in the basal inferolateral LV wall, but how an intracellular storage disease causes focal LGE is unknown. We present a whole-heart histological validation that LGE is caused by focal myocardial collagen scarring. This scarring may be the substrate for electrical re-entry and sudden arrhythmic d...

  18. Cooldown stresses on the coldmass of SSC dipole magnets

    International Nuclear Information System (INIS)

    Aksel, B.; Leung, K.

    1991-05-01

    Cooldown rate is one of the critical factors determining the availability of the Superconducting Super Collider ring because of its large size. Considerable time saving is possible with different cooldown scenarios which generate large temperature gradients on the magnets. Purpose of this study is to understand the stresses generated due to largest possible temperature gradients that can be supplied by the cryogenic system and to predict the relation between the cooling rate and the coil stresses. Under the assumptions made in this study, it is found that maximum coil stress is independent of cooling rate. This result is in contradiction with the general belief and more investigation needs to be done before reaching a definite conclusion. 2 refs., 6 figs

  19. An analytical nonlinear magnetoelectric coupling model of laminated composites under combined pre-stress and magnetic bias loadings

    International Nuclear Information System (INIS)

    Zhou, Hao-Miao; Qu, Shao-Xing; Ou, Xiao-Wei; Xiao, Ying; Wu, Hua-Ping

    2013-01-01

    Based on the equivalent circuit method, this paper adopts the nonlinear magnetostrictive constitutive relations to establish an analytical nonlinear magnetoelectric coefficient model for magnetostrictive/piezoelectric/magnetostrictive laminated magnetoelectric composites. When the pre-stress is set to zero in the model, the predicted results of the magnetoelectric coefficient coincide well with the available experimental results both qualitatively and quantitatively. Using the model, we can qualitatively predict the influence of the pre-stress, magnetic bias fields and the volume fraction of the magnetostrictive material on the magnetoelectric coefficient. The predicted results show that the influences of the pre-stress on the magnetoelectric coefficient, which varies with the magnetic bias field, before and after reaching the magnetoelectric coefficient maximum, are opposite. That is, the influence of the pre-stress on curves of the magnetoelectric coefficient reverses when the magnetoelectric coefficient reaches its maximum. Therefore, the correct setting of the pre-stress can lower the applied magnetic bias field and improve the magnetoelectric coefficient. The established nonlinear magnetoelectric effect model can provide a theoretical basis for regulating the magnetoelectric coefficient by the pre-stress and magnetic bias field and make it possible to design high-precision miniature magnetoelectric devices. (paper)

  20. Non Hodgkin lymphoma metastasis to the heart detected by cardiovascular magnetic resonance; Metastasis cardiaca secundaria al linfoma de Hodgkin detectada por la resonancia magnetica cardiovascular

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Florange; Morales, Marisela; Pedreanez, Norma [Hospital Cardiologico Infantil Latinoamericano Dr Gilberto Rodriguez Ochoa, Carcacas (Venezuela, Bolivarian Republic of); Pabon, Luz; Carrillo, Milton [Universidad Central de Venezuela (UCV/HUC), Caracas (Venezuela, Bolivarian Republic of). Instituto de Hematoncologia. Hospital Universitario; Fernandes, Juliano Lara [Universidade de Campinas (UNICAMP), SP (Brazil)

    2009-10-15

    Primary and secondary heart tumors are relatively rare occurrences but usually imply significant treatment decisions. The differential diagnosis among these tumors and other masses can sometimes be difficult and require the use of different imaging modalities to establish a confident verdict. Cardiovascular magnetic resonance CMR imaging is a very useful tool in these cases by allowing for the application of different strategies to better delineate masses, heart structures and adjacent tissues. In this case description, we present a woman with shortness of breath and a paracardiac mass showing how CMR can be applied. (author)

  1. Slow breathing and cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Ashish Chaddha

    2015-01-01

    Full Text Available Cardiovascular disease is the leading cause of death for both men and women worldwide. Much emphasis has been placed on the primary and secondary prevention of cardiovascular disease. While depression and anxiety increase the risk of developing cardiovascular disease, cardiovascular disease also increases the risk of developing anxiety and depression. Thus, promoting optimal mental health may be important for both primary and secondary prevention of cardiovascular disease. Like lowering blood pressure, lipids, and body weight, lowering anger and hostility and improving depression and anxiety may also be an important intervention in preventive cardiology. As we strive to further improve cardiovascular outcomes, the next bridge to cross may be one of offering patients nonpharmacologic means for combating daily mental stress and promoting mental health, such as yoga and pranayama. Indeed, the best preventive cardiovascular medicine may be a blend of both Western and Eastern medicine.

  2. Influence of stress on morphology and magnetism of heteroepitaxial thin films

    International Nuclear Information System (INIS)

    Wedler, G.

    2001-01-01

    In this thesis the method of the bending-beam technique and the scanning tunnel microscopy was used in order to study the influence of mechanical stresses on growth and magnetoelastic coupling of selected epitaxial thin-layer systems. The Si x Ge 1-x alloy films deposited at 900 K on Si(001) substrates with Si concentrations 20% a change of the stress-behaviour is observed, which lets conclude to pure 3D island growth without wetting layer. Scanning-tunnel-microscopy studies show already at intermediate film thicknesses of 1 nm regular islands with a narrow size distribution. For the explanation of this surprising change of the growth modus the influence of kinetic parameters is discussed. Furthermore for the first time stress measurements of Fe/ GaAs(001) are presented. The behaviour of the film stress at 450 K hints to a few nm thick interdiffusion layer between film and substrate. This interdiffusion is at 300 K only by about 30% reduced and cannot by this be neglected anywhere. By means of on different substrates [Mg(001), lowly stressed Cr(001) buffer layer, GaAs(001)] growed Fe films for the first time a detailed picture of the stress dependence of the magnetoelastic coupling constants B 1 and B 2 of Fe in the layer-density range of 2-100 mm is presented. While the coupling constants of stress-free Fe(001) films exhibit volume behaviour, distinct deviations occur already at small stresses of about 0.1 GPa; at some GPa even the sign changes. The value of B 2 decreases linearly with the film stress up to 6 GPa, in B 1 after an initially linear slope above 2-3 GPa a saturation occurs. Magnetization and magnetic anisotropy however behave in whole studied layer-density range as in the volume

  3. Statins and oxidative stress in the cardiovascular system.

    Science.gov (United States)

    Margaritis, Marios; Sanna, Fabio; Antoniades, Charalambos

    2017-09-26

    Statins are widely established as an important class of medications for primary and secondary prevention of cardiovascular disease. In addition to their lipid-lowering effects, mounting evidence suggests that statins exhibit non-lipid-lowering mediated effects in the cardiovascular system. These so called "pleiotropic" effects are partly due to antioxidant properties of statins. These are mediated by inhibition of the mevalonate pathway, which interferes with small GTP-ase protein prenylation. This, in turn, leads to anti-oxidant effects of statins via a plethora of mechanisms. Statins prevent the activation of the pro-oxidant enzyme NADPH-oxidase by interfering with Rac1 activation and translocation to the membrane, as well as reducing expression of crucial subunits of NADPH-oxidase. Statins also enhance the expression, enzymatic activity and coupling of endothelial nitric oxide synthase (eNOS), through mevalonate-dependent effects. The net result is a restoration of the redox balance in the cardiovascular system, with subsequent anti-atherosclerotic and cardioprotective effects. While the evidence from basic science studies and animal models is strong, more clinical trials are required to establish the relevance of these pleiotropic effects to human cardiovascular disease and potentially lead to expanded indications for statin treatment or alternative therapeutic strategies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Determination of the plastic deformation and residual stress tensor distribution using surface and bulk intrinsic magnetic properties

    International Nuclear Information System (INIS)

    Hristoforou, E.; Svec, P. Sr.

    2015-01-01

    We have developed an unique method to provide the stress calibration curve in steels: performing flaw-less welding in the under examination steel, we obtained to determine the level of the local plastic deformation and the residual stress tensors. These properties where measured using both the X-ray and the neutron diffraction techniques, concerning their surface and bulk stresses type II (intra-grain stresses) respectively, as well as the stress tensor type III by using the electron diffraction technique. Measuring the distribution of these residual stresses along the length of a welded sample or structure, resulted in determining the local stresses from the compressive to tensile yield point. Local measurement of the intrinsic surface and bulk magnetic property tensors allowed for the un-hysteretic correlation. The dependence of these local magnetic tensors with the above mentioned local stress tensors, resulting in a unique and almost un-hysteretic stress calibration curve of each grade of steel. This calibration integrated the steel's mechanical and thermal history, as well as the phase transformations and the presence of precipitations occurring during the welding process.Additionally to that, preliminary results in different grade of steels reveal the existence of a universal law concerning the dependence of magnetic and magnetostrictive properties of steels on their plastic deformation and residual stress state, as they have been accumulated due to their mechanical and thermal fatigue and history. This universality is based on the unique dependence of the intrinsic magnetic properties of steels normalized with a certain magnetoelastic factor, upon the plastic deformation or residual stress state, which, in terms, is normalized with their yield point of stress. (authors)

  5. Magnetic properties of URu2Si2 under uniaxial stress by neutron scattering

    International Nuclear Information System (INIS)

    Bourdarot, Frederic; Martin, Nicolas; Raymond, Stephane; Regnault, Louis-Pierre; Aoki, Dai; Taufour, Valentin; Flouquet, Jacques

    2011-01-01

    The aim of this study is to compare the magnetic behavior of URu 2 Si 2 under uniaxial stress along the a axis with the behavior under hydrostatic pressure. Both are very similar, but uniaxial stress presents a critical stress σ x a [0.33(5) GPa] that is smaller than the hydrostatic critical pressure p x (0.5 GPa) where the ground state switches from a HO (hidden-order) to AF (antiferromagnetic) ground state. From these critical values and Larmor neutron diffraction, we conclude that the magnetic properties are governed by the shortest U-U distance in the plane (a lattice parameter). Under stress, the orthorhombic unit cell stays centered. A key point shown by this study is the presence of a threshold for the uniaxial stress along the a axis before the appearance of the large AF moment, which indicates no mixture of the order parameter between the HO ground state and the AF one as under hydrostatic pressure. The two most intense longitudinal magnetic excitations at Q 0 =(1,0,0) and Q 1 =(0.6,0,0) were measured in the HO state: the excitation at Q 0 decreases in energy while the excitation at Q 1 increases in energy with the uniaxial stress along the a axis. The decrease of the energy of the excitation at Q 0 seems to indicate a critical energy-gap value of 1.2(1) meV at σ x a . A similar value was derived from studies under hydrostatic pressure at p x .

  6. The effect of stress on magnetic Barkhausen activity in ferromagnetic steels

    International Nuclear Information System (INIS)

    Jiles, D.C.

    1989-01-01

    This paper presents results of measurements of the effect of uniaxial tensile stresses of up to 85 MPa on Barkhausen activity and magnetic properties of AISI 4130 and AISI 4140 steels. The results showed that the location of maximum Barkhausen activity was very close to the coercive point. Barkhausen peak height and the total number of pulses were affected by the stress, although there was considerable scatter in some of the results so that it was not clear how the peak height of the AISI 4130 varied with stress

  7. Mechanical stress analysis during a quench in CLIQ protected 16 T dipole magnets designed for the future circular collider

    Science.gov (United States)

    Zhao, Junjie; Prioli, Marco; Stenvall, Antti; Salmi, Tiina; Gao, Yuanwen; Caiffi, Barbara; Lorin, Clement; Marinozzi, Vittorio; Farinon, Stefania; Sorbi, Massimo

    2018-07-01

    Protecting the magnets in case of a quench is a challenge for the 16 T superconducting dipole magnets presently designed for the 100 TeV: Future Circular Collider (FCC). These magnets are driven to the foreseen technological limits in terms of critical current, mechanical strength and quench protection. The magnets are protected with CLIQ (Coupling-Loss Induced Quench) system, which is a recently developed quench protection method based on discharging a capacitor bank across part of the winding. The oscillation of the magnet currents and the dissipation of the high stored energy into the windings cause electrodynamic forces and thermal stresses, which may need to be considered in the magnet mechanical design. This paper focuses on mechanical stress analysis during a quench of the 16 T cos-θ and block type dipole magnets. A finite element model allowed studying the stress due to the non-uniform temperature and current distribution in the superconducting coils. Two different CLIQ configurations were considered for the cos-θ design and one for the block type magnet. The analyses of the mechanical behavior of two magnets during a quench without or with hot spot turn were separately carried out. The simulation results show that the stress related to a quench should be considered when designing a high field magnet.

  8. Stress- and Magnetic Field-Induced Martensitic Transformation at Cryogenic Temperatures in Fe-Mn-Al-Ni Shape Memory Alloys

    Science.gov (United States)

    Xia, Ji; Xu, Xiao; Miyake, Atsushi; Kimura, Yuta; Omori, Toshihiro; Tokunaga, Masashi; Kainuma, Ryosuke

    2017-12-01

    Stress-induced and magnetic-field-induced martensitic transformation behaviors at low temperatures were investigated for Fe-Mn-Al-Ni alloys. The magnetic-field-induced reverse martensitic transformation was directly observed by in situ optical microscopy. Magnetization measurements under pulsed magnetic fields up to 50 T were carried out at temperatures between 4.2 and 125 K on a single-crystal sample; full magnetic-field-induced reverse martensitic transformation was confirmed at all tested temperatures. Compression tests from 10 to 100 K were conducted on a single-crystal sample; full shape recovery was obtained at all tested temperatures. It was found that the temperature dependence of both the critical stress and critical magnetic field is small and that the transformation hysteresis is less sensitive to temperature even at cryogenic temperatures. The temperature dependence of entropy change during martensitic transformation up to 100 K was then derived using the Clausius-Clapeyron relation with critical stresses and magnetic fields.

  9. Gadolinium enhanced cardiovascular magnetic resonance in Anderson-Fabry disease. Evidence for a disease specific abnormality of the myocardial interstitium.

    Science.gov (United States)

    Moon, James C C; Sachdev, Bhavesh; Elkington, Andrew G; McKenna, William J; Mehta, Atul; Pennell, Dudley J; Leed, Philip J; Elliott, Perry M

    2003-12-01

    Anderson-Fabry Disease (AFD), an X-linked disorder of sphingolipid metabolism, is a cause of idiopathic left ventricular hypertrophy but the mechanism of hypertrophy is poorly understood. Gadolinium enhanced cardiovascular magnetic resonance can detect focal myocardial fibrosis. We hypothesised that hyperenhancement would be present in AFD. Eighteen males (mean 43+/-14 years) and eight female heterozygotes (mean 48+/-12 years) with AFD underwent cine and late gadolinium cardiovascular magnetic resonance. Nine male (50%) had myocardial hyperenhancement ranging from 3.4% to 20.6% (mean 7.7+/-5.7%) of total myocardium; in males, percentage hyperenhancement related to LV mass index (r=0.78, P=0.0002) but not to ejection fraction or left ventricular volumes. Lesser hyperenhancement was also found in four (50%) heterozygous females (mean 4.6%). In 12 (92%) patients with abnormal gadolinium uptake, hyperenhancement occurred in the basal infero-lateral wall where, unlike myocardial infarction, it was not sub-endocardial. In two male patients with severe LVH (left ventricular hypertrophy) and systolic impairment there was additional hyperenhancement in other myocardial segments. These observations suggests that myocardial fibrosis occurs in AFD and may contribute to the hypertrophy and the natural history of the disease.

  10. Changes in relative fit of human heat stress indices to cardiovascular, respiratory, and renal hospitalizations across five Australian urban populations

    Science.gov (United States)

    Goldie, James; Alexander, Lisa; Lewis, Sophie C.; Sherwood, Steven C.; Bambrick, Hilary

    2018-03-01

    Various human heat stress indices have been developed to relate atmospheric measures of extreme heat to human health impacts, but the usefulness of different indices across various health impacts and in different populations is poorly understood. This paper determines which heat stress indices best fit hospital admissions for sets of cardiovascular, respiratory, and renal diseases across five Australian cities. We hypothesized that the best indices would be largely dependent on location. We fit parent models to these counts in the summers (November-March) between 2001 and 2013 using negative binomial regression. We then added 15 heat stress indices to these models, ranking their goodness of fit using the Akaike information criterion. Admissions for each health outcome were nearly always higher in hot or humid conditions. Contrary to our hypothesis that location would determine the best-fitting heat stress index, we found that the best indices were related largely by health outcome of interest, rather than location as hypothesized. In particular, heatwave and temperature indices had the best fit to cardiovascular admissions, humidity indices had the best fit to respiratory admissions, and combined heat-humidity indices had the best fit to renal admissions. With a few exceptions, the results were similar across all five cities. The best-fitting heat stress indices appear to be useful across several Australian cities with differing climates, but they may have varying usefulness depending on the outcome of interest. These findings suggest that future research on heat and health impacts, and in particular hospital demand modeling, could better reflect reality if it avoided "all-cause" health outcomes and used heat stress indices appropriate to specific diseases and disease groups.

  11. Changes in relative fit of human heat stress indices to cardiovascular, respiratory, and renal hospitalizations across five Australian urban populations.

    Science.gov (United States)

    Goldie, James; Alexander, Lisa; Lewis, Sophie C; Sherwood, Steven C; Bambrick, Hilary

    2018-03-01

    Various human heat stress indices have been developed to relate atmospheric measures of extreme heat to human health impacts, but the usefulness of different indices across various health impacts and in different populations is poorly understood. This paper determines which heat stress indices best fit hospital admissions for sets of cardiovascular, respiratory, and renal diseases across five Australian cities. We hypothesized that the best indices would be largely dependent on location. We fit parent models to these counts in the summers (November-March) between 2001 and 2013 using negative binomial regression. We then added 15 heat stress indices to these models, ranking their goodness of fit using the Akaike information criterion. Admissions for each health outcome were nearly always higher in hot or humid conditions. Contrary to our hypothesis that location would determine the best-fitting heat stress index, we found that the best indices were related largely by health outcome of interest, rather than location as hypothesized. In particular, heatwave and temperature indices had the best fit to cardiovascular admissions, humidity indices had the best fit to respiratory admissions, and combined heat-humidity indices had the best fit to renal admissions. With a few exceptions, the results were similar across all five cities. The best-fitting heat stress indices appear to be useful across several Australian cities with differing climates, but they may have varying usefulness depending on the outcome of interest. These findings suggest that future research on heat and health impacts, and in particular hospital demand modeling, could better reflect reality if it avoided "all-cause" health outcomes and used heat stress indices appropriate to specific diseases and disease groups.

  12. 21 CFR 870.3690 - Pacemaker test magnet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an inhibited or triggered type...

  13. Structured lifestyle intervention in patients with the metabolic syndrome mitigates oxidative stress but fails to improve measures of cardiovascular autonomic neuropathy.

    Science.gov (United States)

    Pennathur, Subramaniam; Jaiswal, Mamta; Vivekanandan-Giri, Anuradha; White, Elizabeth A; Ang, Lynn; Raffel, David M; Rubenfire, Melvyn; Pop-Busui, Rodica

    2017-09-01

    To assess the role of oxidative stress in mediating adverse outcomes in metabolic syndrome (MetS) and resultant cardiovascular autonomic neuropathy (CAN), and to evaluate the effects of lifestyle interventions on measures of oxidative stress and CAN in subjects with MetS. Pilot study in 25 non-diabetic subjects with MetS (age 49±10years, 76% females) participating in a 24-week lifestyle intervention (supervised aerobic exercise/Mediterranean diet), and 25 age-matched healthy controls. CAN was assessed by cardiovascular reflex tests, heart rate variability (HRV) and PET imaging with sympathetic analog [ 11 C] meta-hydroxyephedrine ([ 11 C]HED). Specific oxidative fingerprints were measured by liquid-chromatography/mass-spectrometry (LC/MS). At baseline, MetS subjects had significantly higher oxidative stress markers [3-nitrotyrosine (234±158 vs. 54±47μmol/mol tyrosine), ortho-tyrosine (59±38 vs. 18±10μmol/molphenylalanine, all P<0.0001], and impaired HRV at rest and during deep breathing (P=0.039 and P=0.021 respectively) compared to controls. Twenty-four-week lifestyle intervention significantly reduced all oxidative stress markers (all P<0.01) but did not change any of the CAN measures. Subjects with MetS present with signs of CAN and increased oxidative stress in the absence of diabetes. The 24-week lifestyle intervention was effective in ameliorating oxidative stress, but did not improve measures of CAN. Larger clinical trials with longer duration are required to confirm these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. "Soldier's Heart": A Genetic Basis for Elevated Cardiovascular Disease Risk Associated with Post-traumatic Stress Disorder.

    Science.gov (United States)

    Pollard, Harvey B; Shivakumar, Chittari; Starr, Joshua; Eidelman, Ofer; Jacobowitz, David M; Dalgard, Clifton L; Srivastava, Meera; Wilkerson, Matthew D; Stein, Murray B; Ursano, Robert J

    2016-01-01

    "Soldier's Heart," is an American Civil War term linking post-traumatic stress disorder (PTSD) with increased propensity for cardiovascular disease (CVD). We have hypothesized that there might be a quantifiable genetic basis for this linkage. To test this hypothesis we identified a comprehensive set of candidate risk genes for PTSD, and tested whether any were also independent risk genes for CVD. A functional analysis algorithm was used to identify associated signaling networks. We identified 106 PTSD studies that report one or more polymorphic variants in 87 candidate genes in 83,463 subjects and controls. The top upstream drivers for these PTSD risk genes are predicted to be the glucocorticoid receptor (NR3C1) and Tumor Necrosis Factor alpha (TNFA). We find that 37 of the PTSD candidate risk genes are also candidate independent risk genes for CVD. The association between PTSD and CVD is significant by Fisher's Exact Test ( P = 3 × 10 -54 ). We also find 15 PTSD risk genes that are independently associated with Type 2 Diabetes Mellitus (T2DM; also significant by Fisher's Exact Test ( P = 1.8 × 10 -16 ). Our findings offer quantitative evidence for a genetic link between post-traumatic stress and cardiovascular disease, Computationally, the common mechanism for this linkage between PTSD and CVD is innate immunity and NFκB-mediated inflammation.

  15. Air pollution, cardiovascular endpoints and susceptibility by stress and material resources: a systematic review of the evidence.

    Science.gov (United States)

    Fuller, Christina H; Feeser, Karla R; Sarnat, Jeremy A; O'Neill, Marie S

    2017-06-14

    Evidence shows that both the physical and social environments play a role in the development of cardiovascular disease. The purpose of this systematic review is two-fold: First, we summarize research from the past 12 years from the growing number of studies focused on effect modification of the relationships between air pollution and cardiovascular disease (CVD) outcomes by socioeconomic position (SEP) and; second, we identify research gaps throughout the published literature on this topic and opportunities for addressing these gaps in future study designs. We identified 30 articles that examined the modifying effects of either material resources or psychosocial stress (both related to SEP) on associations between short and long-term air pollution exposure and CVD endpoints. Although 18 articles identified at least one interaction between an air pollutant and material resource indicator, 11 others did not. Support for susceptibility to air pollution by psychosocial stress was weaker; however, only three articles tested this hypothesis. Further studies are warranted to investigate how air pollution and SEP together may influence CVD. We recommend that such research include thorough assessment of air pollution and SEP correlations, including spatial correlation; investigate air pollution indices or multi-pollutant models; use standardized metrics of SEP to enhance comparability across studies; and evaluate potentially susceptible populations.

  16. Prognostic value of combined CT angiography and myocardial perfusion imaging versus invasive coronary angiography and nuclear stress perfusion imaging in the prediction of major adverse cardiovascular events

    DEFF Research Database (Denmark)

    Chen, Marcus Y.; Rochitte, Carlos E.; Arbab-Zadeh, Armin

    2017-01-01

    Purpose: To compare the prognostic importance (time to major adverse cardiovascular event [MACE]) of combined computed tomography (CT) angiography and CT myocardial stress perfusion imaging with that of combined invasive coronary angiography (ICA) and stress single photon emission CT myocardial p...

  17. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress.

    Science.gov (United States)

    Wawrzyniak, Andrew J; Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-05-01

    Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = -.009, SE = .005, p = .09) and diastolic (B = -.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = -.007, SE = .003, p = .03) and impaired vagal tone (B = -.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses. © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

  18. Number of recent stressful life events and incident cardiovascular disease: Moderation by lifetime depressive disorder.

    Science.gov (United States)

    Berntson, Jessica; Patel, Jay S; Stewart, Jesse C

    2017-08-01

    We investigated whether number of recent stressful life events is associated with incident cardiovascular disease (CVD) and whether this relationship is stronger in adults with a history of clinical depression. Prospective data from 28,583 U.S. adults (mean age=45years) initially free of CVD who participated in Waves 1 (2001-2002) and 2 (2004-2005) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were examined. Number of past-year stressful life events (Wave 1), lifetime depressive disorder (Wave 1), and incident CVD (Wave 2) were determined by structured interviews. There were 1069 cases of incident CVD. Each additional stressful life event was associated with a 15% increased odds of incident CVD [Odds Ratio (OR)=1.15, 95% Confidence Interval (CI): 1.11, 1.19]. As hypothesized, a stressful life events by lifetime depressive disorder interaction was detected (P=0.003). Stratified analyses indicated that stressful life events had a stronger association with incident CVD among adults with (OR=1.18, 95% CI: 1.10, 1.27, n=4908) versus without (OR=1.10, 95% CI: 1.07, 1.14, n=23,675) a lifetime depressive disorder. Our findings suggest that a greater number of recent stressful life events elevate the risk of new-onset CVD and that this risk is potentiated in adults with a history of clinical depression. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Radical Roles for RAGE in the Pathogenesis of Oxidative Stress in Cardiovascular Diseases and Beyond

    Directory of Open Access Journals (Sweden)

    Radha Ananthakrishnan

    2013-10-01

    Full Text Available Oxidative stress is a central mechanism by which the receptor for advanced glycation endproducts (RAGE mediates its pathological effects. Multiple experimental inquiries in RAGE-expressing cultured cells have demonstrated that ligand-RAGE interaction mediates generation of reactive oxygen species (ROS and consequent downstream signal transduction and regulation of gene expression. The primary mechanism by which RAGE generates oxidative stress is via activation of NADPH oxidase; amplification mechanisms in the mitochondria may further drive ROS production. Recent studies indicating that the cytoplasmic domain of RAGE binds to the formin mDia1 provide further support for the critical roles of this pathway in oxidative stress; mDia1 was required for activation of rac1 and NADPH oxidase in primary murine aortic smooth muscle cells treated with RAGE ligand S100B. In vivo, in multiple distinct disease models in animals, RAGE action generates oxidative stress and modulates cellular/tissue fate in range of disorders, such as in myocardial ischemia, atherosclerosis, and aneurysm formation. Blockade or genetic deletion of RAGE was shown to be protective in these settings. Indeed, beyond cardiovascular disease, evidence is accruing in human subjects linking levels of RAGE ligands and soluble RAGE to oxidative stress in disorders such as doxorubicin toxicity, acetaminophen toxicity, neurodegeneration, hyperlipidemia, diabetes, preeclampsia, rheumatoid arthritis and pulmonary fibrosis. Blockade of RAGE signal transduction may be a key strategy for the prevention of the deleterious consequences of oxidative stress, particularly in chronic disease.

  20. Strain and stress of the ASDEX multipole magnetic coils

    International Nuclear Information System (INIS)

    Jandl, O.; Pillsticker, M.

    1978-01-01

    A brief description of the technical concept of the multipole magnetic field coils for the ASDEX tokamak is given. The various loads of the coils are explained in quality. To compute displacement and stress of the coils FEM computer programs are used. The computing models applied to this problem are founded and the results and the conclusions are reported. (orig.) [de

  1. Effect of thickness on structure, microstructure, residual stress and soft magnetic properties of DC sputtered Fe65Co35 soft magnetic thin films

    International Nuclear Information System (INIS)

    Prasanna Kumari, T.; Manivel Raja, M.; Kumar, Atul; Srinath, S.; Kamat, S.V.

    2014-01-01

    The effect of film thickness on structure, microstructure, residual stress and soft magnetic properties of Fe 65 Co 35 thin films deposited on Si(001) and MgO(001) substrates was investigated by varying film thickness from 30 to 600 nm. X-ray diffraction studies showed that the FeCo films are polycrystalline in the as-deposited condition irrespective of deposition on Si or MgO substrate. The microstructure of films consisted of spherical grains for 30 nm film thickness and columnar grains for all other film thicknesses. The grain size for the films was found to increase from 15 to 50 nm with increasing film thickness. The sputtered films also exhibited tensile residual stresses with the magnitude of stress decreasing with increasing film thickness. The Fe 65 Co 35 films deposited on both substrates also exhibited very good in-plane soft magnetic properties with a saturation magnetization 4πM s of ∼23.6–23.8 kG and coercivity of ∼27–30 Oe without any under-layer only for films with thickness of 30 nm. For all other thicknesses, these films exhibited a significantly higher coercivity. The observed variations in soft magnetic properties with film thickness were explained in terms of residual stress and microstructure of the films. - Highlights: • Spherical grain morphology transformed to columnar above 30 nm film thickness. • Sputtered films exhibited tensile residual stresses decreasing with film thickness. • An in-plane coercivity of ∼27–30 Oe was achieved without any under-layer

  2. Cardiovascular Parameters of Nigerian Physiotherapy Students Dur ...

    African Journals Online (AJOL)

    Examination and tests are routine academic task during which students engage in mental exercis-es, writing, and/or practical demonstrations under pressure with stress placed on the cardiovascu-lar system. This study was aimed at investigating the cardiovascular parameters of students before, during and after an ...

  3. Cardiovascular magnetic resonance physics for clinicians: part I.

    Science.gov (United States)

    Ridgway, John P

    2010-11-30

    There are many excellent specialised texts and articles that describe the physical principles of cardiovascular magnetic resonance (CMR) techniques. There are also many texts written with the clinician in mind that provide an understandable, more general introduction to the basic physical principles of magnetic resonance (MR) techniques and applications. There are however very few texts or articles that attempt to provide a basic MR physics introduction that is tailored for clinicians using CMR in their daily practice. This is the first of two reviews that are intended to cover the essential aspects of CMR physics in a way that is understandable and relevant to this group. It begins by explaining the basic physical principles of MR, including a description of the main components of an MR imaging system and the three types of magnetic field that they generate. The origin and method of production of the MR signal in biological systems are explained, focusing in particular on the two tissue magnetisation relaxation properties (T1 and T2) that give rise to signal differences from tissues, showing how they can be exploited to generate image contrast for tissue characterisation. The method most commonly used to localise and encode MR signal echoes to form a cross sectional image is described, introducing the concept of k-space and showing how the MR signal data stored within it relates to properties within the reconstructed image. Before describing the CMR acquisition methods in detail, the basic spin echo and gradient pulse sequences are introduced, identifying the key parameters that influence image contrast, including appearances in the presence of flowing blood, resolution and image acquisition time. The main derivatives of these two pulse sequences used for cardiac imaging are then described in more detail. Two of the key requirements for CMR are the need for data acquisition first to be to be synchronised with the subject's ECG and to be fast enough for the subject

  4. Sex differences in platelet reactivity and cardiovascular and psychological response to mental stress in patients with stable ischemic heart disease: insights from the REMIT study.

    Science.gov (United States)

    Samad, Zainab; Boyle, Stephen; Ersboll, Mads; Vora, Amit N; Zhang, Ye; Becker, Richard C; Williams, Redford; Kuhn, Cynthia; Ortel, Thomas L; Rogers, Joseph G; O'Connor, Christopher M; Velazquez, Eric J; Jiang, Wei

    2014-10-21

    Although emotional stress is associated with ischemic heart disease (IHD) and related clinical events, sex-specific differences in the psychobiological response to mental stress have not been clearly identified. We aimed to study the differential psychological and cardiovascular responses to mental stress between male and female patients with stable IHD. Patients with stable IHD enrolled in the REMIT (Responses of Mental Stress-Induced Myocardial Ischemia to Escitalopram) study underwent psychometric assessments, transthoracic echocardiography, and platelet aggregation studies at baseline and after 3 mental stress tasks. Mental stress-induced myocardial ischemia (MSIMI) was defined as the development or worsening of regional wall motion abnormality, reduction of left ventricular ejection fraction (LVEF) ≥8% by transthoracic echocardiography, and/or ischemic ST-segment change on electrocardiogram during 1 or more of the 3 mental stress tasks. In the 310 participants with known IHD (18% women, 82% men), most baseline characteristics were similar between women and men (including heart rate, blood pressure, and LVEF), although women were more likely to be nonwhite, living alone (p mental stress, women had more MSIMI (57% vs. 41%; p mental stress in women and men. Further studies should test the association of sex differences in cardiovascular and platelet reactivity in response to mental stress and long-term outcomes. (Responses of Myocardial Ischemia to Escitalopram Treatment [REMIT]; NCT00574847). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  5. O-GlcNAc and the Cardiovascular System

    Science.gov (United States)

    Dassanayaka, Sujith; Jones, Steven P.

    2014-01-01

    The cardiovascular system is capable of robust changes in response to physiologic and pathologic stimuli through intricate signaling mechanisms. The area of metabolism has witnessed a veritable renaissance in the cardiovascular system. In particular, the post-translational β-O-linkage of N-acetylglucosamine (O-GlcNAc) to cellular proteins represents one such signaling pathway that has been implicated in the pathophysiology of cardiovascular disease. This highly dynamic protein modification may induce functional changes in proteins and regulate key cellular processes including translation, transcription, and cell death. In addition, its potential interplay with phosphorylation provides an additional layer of complexity to post-translational regulation. The hexosamine biosynthetic pathway generally requires glucose to form the nucleotide sugar, UDP-GlcNAc. Accordingly, O-GlcNAcylation may be altered in response to nutrient availability and cellular stress. Recent literature supports O-GlcNAcylation as an autoprotective response in models of acute stress (hypoxia, ischemia, oxidative stress). Models of sustained stress, such as pressure overload hypertrophy, and infarct-induced heart failure, may also require protein O-GlcNAcylation as a partial compensatory mechanism. Yet, in models of Type II diabetes, O-GlcNAcylation has been implicated in the subsequent development of vascular, and even cardiac, dysfunction. This review will address this apparent paradox and discuss the potential mechanisms of O-GlcNAc-mediated cardioprotection and cardiovascular dysfunction. This discussion will also address potential targets for pharmacologic interventions and the unique considerations related to such targets. PMID:24287310

  6. Manganese substituted cobalt ferrite magnetostrictive materials for magnetic stress sensor applications

    OpenAIRE

    Paulsen, J. A.; Ring, A. P.; Lo, C. C. H.; Snyder, John Evan; Jiles, David

    2005-01-01

    Metal bonded cobalt ferrite composites have been shown to be promising candidate materials for use in magnetoelastic stress sensors, due to their large magnetostriction and high sensitivity of magnetization to stress. However previous results have shown that below 60 °C the cobalt ferrite material exhibits substantial magnetomechanical hysteresis. In the current study, measurements indicate that substituting Mn for some of the Fe in the cobalt ferrite can lower the Curie temperature of the ma...

  7. Evaluation of initial degradation in stress corrosion cracking by magnetic methods

    International Nuclear Information System (INIS)

    Takaya, Shigeru; Suzuki, Takayuki; Matsumoto, Yoshihiro; Demachi, Kazuyuki; Uesaka, Mitsuru

    2003-01-01

    Two magnetic methods are proposed for the evaluation of initial degradations of type 304 stainless steel in stress corrosion cracking (SCC). The first one is the measurement of the distribution of chromium depletion by means of a magnetic force microscope (MFM). MFM observations are performed for some samples sensitized in various conditions, and the obtained results coincide with the expected ones from the chromium behavior. Moreover, the phase distributions in the solution-annealed and sensitized states are observed by electron backscatter pattern technique. The observation results show that the phase transformation from the austenite phase to the martensite phase occurred along grain boundaries where the chromium was depleted. The second one is the detection of initial SCC cracks by measurement of magnetic flux densities. In-situ measurement of magnetic flux density during the SCC test and MFM observation reveal the relation of initial SCC cracks and magnetic properties. (author)

  8. Stressed state of a cement electrical insulation of a pulsed magnet

    International Nuclear Information System (INIS)

    Korenevskij, V.V.; Sugak, E.B.; Fedorenko, L.I.

    1985-01-01

    The stresses arising in cement electrical insulation of a pulsed magnet intended for separation and scanning of beam of secondary particles with 5-10 MeV energy are investigated during its switching. The magnet represents a single-turn construction. During its switching repulsion forces arise in copper buses which affect the core consisting of a set of iron plates. In its turn two cores trying to separate transmit impact load onto cement electrical insulation, the mechanical strength of which determines the construction durability on the whole. For selection of calculation technique the method of photoelasticity is used on models of transparent polymeric materials. Epoxy resin served as material for insulation model, duraluminium for the rest of magnet parts. It is concluded that the calculation technique for the magnet under investigation is a hingeless circular arc

  9. Stress and Health

    DEFF Research Database (Denmark)

    Rod, Naja Hulvej

    2014-01-01

    and behavioral mechanisms. Stress is a complex concept and in order to better understand the relation between stress and health, the dissertation works with a clear distinction between the health consequences of different types of stress including external stressors, perceived stress, and measures of the stress......’s disease patients. Results The combined evidence of this dissertation shows a moderately higher risk of some common chronic disorders including cardiovascular disease and atopic disorders among individuals exposed to work-related stressors and perceived stress. Most empirical studies also report higher...... of pathways. The physiological stress response has the ability to directly affect vital body systems including the cardiovascular, immune, and metabolic systems. Further, stress can lead to unfavorable changes in health-related behavior, impaired sleep and poor mental health. An increasing number of well...

  10. The influence of punching process on residual stress and magnetic domain structure of non-oriented silicon steel

    International Nuclear Information System (INIS)

    Cao, Hongzhi; Hao, Linpo; Yi, Jingwen; Zhang, Xianglin; Luo, Zhonghan; Chen, Shenglin; Li, Rongfeng

    2016-01-01

    The main purpose of this paper is to investigate the influence of punching process on residual stress and magnetic domain structure. The residual stress in non-oriented silicon steel after punching process was measured by nanoindentation. The maximum depth was kept constant as 300 nm during nanoindentation. The material around indentation region exhibited no significant pile-up deformation. The calculation of residual stress was based on the Suresh theoretical model. Our experimental results show that residual compressive stress was generated around the sheared edge after punching. The width of residual stress affected zone by punching was around 0.4–0.5 mm. After annealing treatment, the residual stress was significantly decreased. Magnetic domain structure was observed according to the Bitter method. The un-annealed sample exhibited complicated domain patterns, and the widths of the magnetic domains varied between 3 µm and 8 µm. Most of the domain patterns of the annealed sample were 180°-domains and 90°-domains, and the widths of the domains decreased to 1–3 µm. - Highlights: • The residual stress distribution on sheared edge was measured. • The residual compressive stress was generated around the sheared edge. • The width of residual stress affected zone was about 0.4–0.5 mm. • The shape and width of the domain structure would be changed by annealing.

  11. Role of oxidative stress in cardiovascular disease outcomes following exposure to ambient air pollution.

    Science.gov (United States)

    Kelly, Frank J; Fussell, Julia C

    2017-09-01

    Exposure to ambient air pollution is associated with adverse cardiovascular outcomes. These are manifested through several, likely overlapping, pathways including at the functional level, endothelial dysfunction, atherosclerosis, pro-coagulation and alterations in autonomic nervous system balance and blood pressure. At numerous points within each of these pathways, there is potential for cellular oxidative imbalances to occur. The current review examines epidemiological, occupational and controlled exposure studies and research employing healthy and diseased animal models, isolated organs and cell cultures in assessing the importance of the pro-oxidant potential of air pollution in the development of cardiovascular disease outcomes. The collective body of data provides evidence that oxidative stress (OS) is not only central to eliciting specific cardiac endpoints, but is also implicated in modulating the risk of succumbing to cardiovascular disease, sensitivity to ischemia/reperfusion injury and the onset and progression of metabolic disease following ambient pollution exposure. To add to this large research effort conducted to date, further work is required to provide greater insight into areas such as (a) whether an oxidative imbalance triggers and/or worsens the effect and/or is representative of the consequence of disease progression, (b) OS pathways and cardiac outcomes caused by individual pollutants within air pollution mixtures, or as a consequence of inter-pollutant interactions and (c) potential protection provided by nutritional supplements and/or pharmacological agents with antioxidant properties, in susceptible populations residing in polluted urban cities. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Photoelastic and analytical investigation of stress in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.; Gray, W.H.

    1975-01-01

    A series of two-dimensional photoelastic stress analyses on circular and oval toroidal magnetic field coils for fusion reactors were made. The circumferential variation of the coil's magnetic force was simulated by applying different pressures to sixteen segmented regions of the inner surface of the models. Isochromatics and isoclinics were measured at selected points on the loaded model in a transmission polariscope using a microphotometer. Separate principal stresses were obtained using the combination of photoelastic information and isopachic data measured from the solution of Laplace's equation by the electrical analog method. Analysis of the same coil geometries, loadings, and boundary conditions were made using the finite element method. General agreement between theory and experiment was realized. From this investigation several variations of coil geometry and methods of support were evaluated. Based upon this experiment, suggestions for optimum structural design of toroidal field coils are presented

  13. Lifestyle dominates cardiovascular risks in Malaysia

    Directory of Open Access Journals (Sweden)

    Khalib A. Latiff

    2008-03-01

    Full Text Available Cardiovascular problem is one of the leading cause of death in Malaysia and now invaded to the sub-urban and rural areas. To prevent and control of this problem, several main risk factors needed to be known and shall be reexamined and ranked according to the priority. The objectives of this research paper was to identify several dominant risk factor related to cardiovascular problem. A cross sectional study was carried out from March 2000 – June 2001 on a total of 8159 rural population aged 18 and above to measure the prevalence of the common cardiovascular risk factors. Those risk factors are systolic blood pressure, diastolic blood pressure, serum cholesterol level, obesity index, blood glucose level, smoking, physical activity and mental stress. Overall prevalence of common cardiovascular risk factors were higher, dominated by physical inactivity (65.7%, hypercholesterolemia – TC:HC (62.3%, mental stress (55.5% and obesity (53.7%. Smoking was also high at 49.9% especially among men. However systolic hypertension, diastolic hypertension and diabetes mellitus; although increased by age, its prevalence is relatively low at 23.7%, 19.2%, and 6.3% respectively. Cardiovascular risk factors related to lifestyle are much evidenced as compared to risk factors related to the biological influence. Therefore, all initiatives in community health intervention should be mobilized specifically on prevention and control of lifestyle-related risk factors. (Med J Indones 2008; 17: 50-6Keywords: cardiovascular problem, community intervention, lifestyle-linked risk factors

  14. The use of magnetic Barkhausen noise analysis for nondestructive determination of stresses in structural elements

    International Nuclear Information System (INIS)

    Silva Junior, Silverio Ferreira da; Mansur, Tanius Rodrigues; Cruz, Julio Ricardo Barreto

    2007-01-01

    The knowledge about the stress state acting in structural elements has significant importance in the structural integrity evaluation of a specific component. The magnetic Barkhausen noise analysis can be used for this purpose. As a nondestructive testing method, it presents the advantage of not promote any changes in the tested component. In this paper, a study about the use of this new nondestructive test method for stress measurements is presented. The test system configuration and the reference standards used for this purpose, as well as the optimum test parameters determination are discussed. The experiments were carried out in ASTM A-36 steel, used for structural components manufacturing. A structure of this material was loaded and the resulting stresses were determined from strain gage measurements and Barkhausen noise analysis. The results obtained have showed a good sensitivity of the magnetic Barkhausen noise to stress changes occurred in the material. The main advantages and limitations of this test method for stress measurements are presented. (author)

  15. Deep-brain magnetic stimulation promotes adult hippocampal neurogenesis and alleviates stress-related behaviors in mouse models for neuropsychiatric disorders

    Science.gov (United States)

    2014-01-01

    Background Repetitive Transcranial Magnetic Stimulation (rTMS)/ Deep-brain Magnetic Stimulation (DMS) is an effective therapy for various neuropsychiatric disorders including major depression disorder. The molecular and cellular mechanisms underlying the impacts of rTMS/DMS on the brain are not yet fully understood. Results Here we studied the effects of deep-brain magnetic stimulation to brain on the molecular and cellular level. We examined the adult hippocampal neurogenesis and hippocampal synaptic plasticity of rodent under stress conditions with deep-brain magnetic stimulation treatment. We found that DMS promotes adult hippocampal neurogenesis significantly and facilitates the development of adult new-born neurons. Remarkably, DMS exerts anti-depression effects in the learned helplessness mouse model and rescues hippocampal long-term plasticity impaired by restraint stress in rats. Moreover, DMS alleviates the stress response in a mouse model for Rett syndrome and prolongs the life span of these animals dramatically. Conclusions Deep-brain magnetic stimulation greatly facilitates adult hippocampal neurogenesis and maturation, also alleviates depression and stress-related responses in animal models. PMID:24512669

  16. Octupolar out-of-plane magnetic field structure generation during collisionless magnetic reconnection in a stressed X-point collapse

    Energy Technology Data Exchange (ETDEWEB)

    Graf von der Pahlen, J.; Tsiklauri, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-06-15

    The out-of-plane magnetic field, generated by fast magnetic reconnection, during collisionless, stressed X-point collapse, was studied with a kinetic, 2.5D, fully electromagnetic, relativistic particle-in-cell numerical code, using both closed (flux conserving) and open boundary conditions on a square grid. It was discovered that the well known quadrupolar structure in the out-of-plane magnetic field gains four additional regions of opposite magnetic polarity, emerging near the corners of the simulation box, moving towards the X-point. The emerging, outer, magnetic field structure has opposite polarity to the inner quadrupolar structure, leading to an overall octupolar structure. Using Ampere's law and integrating electron and ion currents, defined at grid cells, over the simulation domain, contributions to the out-of-plane magnetic field from electron and ion currents were determined. The emerging regions of opposite magnetic polarity were shown to be the result of ion currents. Magnetic octupolar structure is found to be a signature of X-point collapse, rather than tearing mode, and factors relating to potential discoveries in experimental scenarios or space-craft observations are discussed.

  17. Significance of left ventricular apical-basal muscle bundle identified by cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

    OpenAIRE

    Gruner, Christiane; Chan, Raymond H.; Crean, Andrew; Rakowski, Harry; Rowin, Ethan J.; Care, Melanie; Deva, Djeven; Williams, Lynne; Appelbaum, Evan; Gibson, C. Michael; Lesser, John R.; Haas, Tammy S.; Udelson, James E.; Manning, Warren J.; Siminovitch, Katherine

    2017-01-01

    Aims Cardiovascular magnetic resonance (CMR) has improved diagnostic and management strategies in hypertrophic cardiomyopathy (HCM) by expanding our appreciation for the diverse phenotypic expression. We sought to characterize the prevalence and clinical significance of a recently identified accessory left ventricular (LV) muscle bundle extending from the apex to the basal septum or anterior wall (i.e. apical-basal). Methods and results CMR was performed in 230 genotyped HCM patients (48 ± 15...

  18. Dynamic stress effects in technical superconductors and the ''training'' problem of superconducting magnets

    International Nuclear Information System (INIS)

    Pasztor, G.; Schmidt, C.

    1978-01-01

    The behavior of NbTi superconductors under dynamic mechanical stress was investigated. A training effect was found in short-sample tests when the conductor was strained in a magnetic field and with a transport current applied. Possible mechanisms are discussed which were proposed to explain training in short samples and in magnets. A stress-induced microplastic as well as an incomplete pseudoelastic behavior of NbTi was detected by monitoring acoustic emission. The experiments support the hypothesis that microplastic or shape memory effects in NbTi involving dislocation processes are responsible for training. The minimum energy needed to induce a normal transition in short-sample tests is calculated with a computer program, which gives the exact solution of the heat equation. A prestrain treatment of the conductor at room temperature is shown to be a simple method of reducing training of short samples and of magnets. This is a direct proof that the same mechanisms are involved in both cases

  19. Clinical application of nuclear magnetic resonance imaging (resistive type) on cardiovascular disease

    International Nuclear Information System (INIS)

    Imai, Hitoshi; Yoshida, Katsuya; Watanabe, Shigeru; Masuda, Yoshiaki; Inagaki, Yoshiaki; Ikehira, Hiroo; Fukuda, Nobuo; Tateno, Yukio.

    1984-01-01

    In order to evaluate the usefulness of Nuclear Magnetic Resonance (NMR) imaging in diagnosing cardiovascular disease, 27 subjects were examined using a 0.1-Tesla resistive type (ASAHI MARK-J). In 10 normal subjects, four cardiac chambers, interventricular septum, aorta, pulmonary vessels and vena cava were clearly identified in NMR imaging. In two patients with old anteroseptal myocardial infarction, anteroseptal wall thinning and left ventricular aneurysm with mural thrombi were demonstrated. In two cases of antrolateral and posterolateral myocardial infarction, however, infarcted areas were not identified in NMR imaging. In one patient with congestive cardiomyopathy, enlarged left ventricle without hypertrophy was recognized. In two patients with hypertrophic obstructive cardiomyopathy, NMR imaging disclosed thickened left ventricular wall associated with its narrowed cavity. A mural thrombus in the right ventricle was distinctly visualized in one patient with cardio-vascular Behcet's disease. In two patients with mitral valve stenosis, enlarged left atrium with a mural thrombus was clearly demonstrated in both cross and longitudinal sections. In three patients with thoratic aortic aneurysm, local dilatation of aorta and mural thrombi were recognized. In four patients with dissecting aortic aneurysm, double channels with an intimal flap in the aorta were visualized in NMR imaging. Mean T 1 values and standard deviations of left ventricle, left ventricular wall, and thrombi were 593+-89, 341+-20, 316+-84 msec, respectively. Mean T 1 values of thrombi were ordinally shorter than those of left ventricule. But some thrombi which might be expected fresh had longer T 1 values. (J.P.N.)

  20. “Soldier's Heart”: A Genetic Basis for Elevated Cardiovascular Disease Risk Associated with Post-traumatic Stress Disorder

    Science.gov (United States)

    Pollard, Harvey B.; Shivakumar, Chittari; Starr, Joshua; Eidelman, Ofer; Jacobowitz, David M.; Dalgard, Clifton L.; Srivastava, Meera; Wilkerson, Matthew D.; Stein, Murray B.; Ursano, Robert J.

    2016-01-01

    “Soldier's Heart,” is an American Civil War term linking post-traumatic stress disorder (PTSD) with increased propensity for cardiovascular disease (CVD). We have hypothesized that there might be a quantifiable genetic basis for this linkage. To test this hypothesis we identified a comprehensive set of candidate risk genes for PTSD, and tested whether any were also independent risk genes for CVD. A functional analysis algorithm was used to identify associated signaling networks. We identified 106 PTSD studies that report one or more polymorphic variants in 87 candidate genes in 83,463 subjects and controls. The top upstream drivers for these PTSD risk genes are predicted to be the glucocorticoid receptor (NR3C1) and Tumor Necrosis Factor alpha (TNFA). We find that 37 of the PTSD candidate risk genes are also candidate independent risk genes for CVD. The association between PTSD and CVD is significant by Fisher's Exact Test (P = 3 × 10−54). We also find 15 PTSD risk genes that are independently associated with Type 2 Diabetes Mellitus (T2DM; also significant by Fisher's Exact Test (P = 1.8 × 10−16). Our findings offer quantitative evidence for a genetic link between post-traumatic stress and cardiovascular disease, Computationally, the common mechanism for this linkage between PTSD and CVD is innate immunity and NFκB-mediated inflammation. PMID:27721742

  1. Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

    OpenAIRE

    Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

    2017-01-01

    AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fract...

  2. Cardiovascular risk factors and collateral artery formation.

    Science.gov (United States)

    de Groot, D; Pasterkamp, G; Hoefer, I E

    2009-12-01

    Arterial lumen narrowing and vascular occlusion is the actual cause of morbidity and mortality in atherosclerotic disease. Collateral artery formation (arteriogenesis) refers to an active remodelling of non-functional vascular anastomoses to functional collateral arteries, capable to bypass the site of obstruction and preserve the tissue that is jeopardized by ischaemia. Hemodynamic forces such as shear stress and wall stress play a pivotal role in collateral artery formation, accompanied by the expression of various cytokines and invasion of circulating leucocytes. Arteriogenesis hence represents an important compensatory mechanism for atherosclerotic vessel occlusion. As arteriogenesis mostly occurs when lumen narrowing by atherosclerotic plaques takes place, presence of cardiovascular risk factors (e.g. hypertension, hypercholesterolaemia and diabetes) is highly likely. Risk factors for atherosclerotic disease affect collateral artery growth directly and indirectly by altering hemodynamic forces or influencing cellular function and proliferation. Adequate collateralization varies significantly among atherosclerotic patients, some profit from the presence of extensive collateral networks, whereas others do not. Cardiovascular risk factors could increase the risk of adverse cardiovascular events in certain patients because of the reduced protection through an alternative vascular network. Likewise, drugs primarily thought to control cardiovascular risk factors might contribute or counteract collateral artery growth. This review summarizes current knowledge on the influence of cardiovascular risk factors and the effects of cardiovascular medication on the development of collateral vessels in experimental and clinical studies.

  3. Intermittent hypoxia, cardiovascular disease and obstructive sleep apnoea.

    Science.gov (United States)

    Turnbull, Chris D

    2018-01-01

    Obstructive sleep apnoea (OSA) is a common disorder and is associated with cardiovascular disease. Continuous positive airway pressure (CPAP), whilst reducing blood pressure, has not been shown to reduce cardiovascular events when used as a treatment solely for this purpose in patients with previous cardiovascular disease. Developing a better understanding of the mechanisms underlying cardiovascular disease in OSA is important to develop new treatments. Potential causative mechanisms for cardiovascular disease in OSA include arousal induced sympathetic activation, large intrathoracic pressure swings leading to shear stress on the heart and great vessels, and intermittent hypoxia (IH). This review discusses the role of IH, as a major physiological consequence of OSA, in the development of cardiovascular disease.

  4. The antioxidant acetylcysteine reduces cardiovascular events in patients with end-stage renal failure: a randomized, controlled trial

    DEFF Research Database (Denmark)

    Tepel, Martin; van der Giet, Markus; Statz, Mario

    2003-01-01

    Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality. Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown.......Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality. Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown....

  5. 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.

  6. Stress Analysis of the D-Zero Solenoid Magnet Lifting Fixture PPD Fixture No.102

    International Nuclear Information System (INIS)

    Zaczek, M.

    1997-01-01

    This engineering note presents stress analysis calculations for the below the hook lifting fixture which will be used to move the D-Zero solenoid magnet during installation work at the D-Zero Assembly building. Load bearing structural members are shown to have a minimum design factor of 3 based on yield strength as required by ASME B30.20. All bolts were analyzed and shown to be kept below allowable loads/stresses listed in the American Institute of Steel Construction (AISC) manual. The lifting fixture will be manufactured at Fermilab using some material scavenged from an existing lifting fixture that was shipped with the magnet from the magnet manufacturer, Toshiba Corporation. The fixture is designed with built in versatility so that the solenoid magnet can be maneuvered through the stages of preparation and installation into it's final mounted position. The structure has been analyzed for all phases of its use, although the analysis of the structure as a below the hook lifting device is the main purpose of this note.

  7. Permeability and stress-jump effects on magnetic drug targeting in a permeable microvessel using Darcy model

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, S., E-mail: sachinshaw@gmail.com [Department of Mathematics and Statistical Sciences, Botswana International University of Science and Technology, Private Bag 16, Palapye (Botswana); Sutradhar, A.; Murthy, PVSN [Department of Mathematics, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal (India)

    2017-05-01

    In the present paper, we investigated the influence of permeability of the carrier particle and stress jump condition on the porous spherical surface in magnetic drug targeting through a permeable microvessel. The nature of blood is defined by non-Newtonian Casson fluid in the core region of the microvessel and Newtonian fluid in the peripheral region which is located near the surface of the wall of the microvessel. The magnetic particles are considered as spherical and in nanosize, embedded in the carrier particle along with drug particles. A magnet is placed near the tumor position to generate a magnetic field. The relative motion of the carrier particle is the resultant of the fluidic force, magnetic force and Saffman drag force which are calculated for the spherical carrier particle. Trajectories of the carrier particle along the radial and axial direction are calculated. Effect of different parameters such as stress-jump constant, permeability of the carrier particle, pressure gradient, yield stress, Saffman force, volume fraction of the embedded magnetic nanoparticles, permeability of the microvessel wall, and the radius of the carrier particle on the trajectory of the carrier particle are discussed and displayed graphically. - Highlights: • In the present manuscript, we considered the porous carrier particle which provide a larger surface area contact with the fluid than the solid spherical carrier particle. It shows that the porous carrier particle are captured easily than the solid carrier particle. • Introduce Suffman force on the carrier particle which commences an additional resistance which acts opposite to the surface wall and helps the particles to go away from the tumor position. • Considered stress jump condition at the surface of the porous carrier particle which enhanced the tendency of the carrier particle to be capture near the tumor. • Used Darcy model to define the permeability of the wall of the microvessel.

  8. Oxidative stress-induced telomeric erosion as a mechanism underlying airborne particulate matter-related cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Grahame Thomas J

    2012-06-01

    Full Text Available Abstract Particulate matter (PM pollution is responsible for hundreds of thousands of deaths worldwide, the majority due to cardiovascular disease (CVD. While many potential pathophysiological mechanisms have been proposed, there is not yet a consensus as to which are most important in causing pollution-related morbidity/mortality. Nor is there consensus regarding which specific types of PM are most likely to affect public health in this regard. One toxicological mechanism linking exposure to airborne PM with CVD outcomes is oxidative stress, a contributor to the development of CVD risk factors including atherosclerosis. Recent work suggests that accelerated shortening of telomeres and, thus, early senescence of cells may be an important pathway by which oxidative stress may accelerate biological aging and the resultant development of age-related morbidity. This pathway may explain a significant proportion of PM-related adverse health outcomes, since shortened telomeres accelerate the progression of many diseases. There is limited but consistent evidence that vehicular emissions produce oxidative stress in humans. Given that oxidative stress is associated with accelerated erosion of telomeres, and that shortened telomeres are linked with acceleration of biological ageing and greater incidence of various age-related pathology, including CVD, it is hypothesized that associations noted between certain pollution types and sources and oxidative stress may reflect a mechanism by which these pollutants result in CVD-related morbidity and mortality, namely accelerated aging via enhanced erosion of telomeres. This paper reviews the literature providing links among oxidative stress, accelerated erosion of telomeres, CVD, and specific sources and types of air pollutants. If certain PM species/sources might be responsible for adverse health outcomes via the proposed mechanism, perhaps the pathway to reducing mortality/morbidity from PM would become clearer

  9. Stress-induced heating in commercial conductors and its possible influence on magnet performance

    International Nuclear Information System (INIS)

    Easton, D.S.; Kroeger, D.M.; Moazed, A.

    1976-01-01

    Calorimetric measurements show that significant amounts of heat are generated when a multifilamentary composite conductor is stressed in tension to levels expected to occur in large, high-field magnet systems. When the stress on the conductor is repetitively cycled between zero and some maximum value, the amount of heat produced per cycle is constant after the first few cycles. Comparison is made between calorimetric determinations of heat injections and the work done on the specimen as indicated by stress-strain curves. Stress-strain curves for a number of commercial conductors indicate that the most important determinant of the magnitude of this effect is the choice of matrix material

  10. Heat- and cold-stress effects on cardiovascular mortality and morbidity among urban and rural populations in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Urban, Aleš; Davídkovová, Hana; Kyselý, Jan

    2014-01-01

    Roč. 58, č. 6 (2014), s. 1057-1068 ISSN 0020-7128 R&D Projects: GA ČR(CZ) GAP209/11/1985 Institutional support: RVO:68378289 Keywords : heat and cold stress * cardiovascular disease * mortality * morbidity * urban and rural differences * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.246, year: 2014 http://link.springer.com/article/10.1007%2Fs00484-013-0693-4#page-1

  11. How does the brain affect cardiovascular health?

    Directory of Open Access Journals (Sweden)

    Vitaliy Bezsheiko

    2017-08-01

    Full Text Available In the article the mechanisms of stress response regulation by the brain are reviewed, as well as the data from a new study in this area, which was focused on a detailed analysis of brain activity changes in people with excessive cardiovascular stress response.

  12. Turbulent stress measurements with phase-contrast magnetic resonance through tilted slices

    Energy Technology Data Exchange (ETDEWEB)

    MacKenzie, Jordan; Soederberg, Daniel; Lundell, Fredrik [Linne FLOW Centre, KTH Mechanics, Stockholm (Sweden); Swerin, Agne [SP Technical Research Institute of Sweden-Chemistry, Materials and Surfaces, Stockholm (Sweden); KTH Royal Institute of Technology, Surface and Corrosion Science, Stockholm (Sweden)

    2017-05-15

    Aiming at turbulent measurements in opaque suspensions, a simplistic methodology for measuring the turbulent stresses with phase-contrast magnetic resonance velocimetry is described. The method relies on flow-compensated and flow-encoding protocols with the flow encoding gradient normal to the slice. The experimental data is compared with direct numerical simulations (DNS), both directly but also, more importantly, after spatial averaging of the DNS data that resembles the measurement and data treatment of the experimental data. The results show that the most important MRI data (streamwise velocity, streamwise variance and Reynolds shear stress) is reliable up to at least anti r = 0.75 without any correction, paving the way for dearly needed turbulence and stress measurements in opaque suspensions. (orig.)

  13. Demountable low stress high field toroidal field magnet system for tokamak fusion reactors

    International Nuclear Information System (INIS)

    Powell, J.; Hsieh, D.; Lehner, J.; Suenaga, M.

    1977-01-01

    A new type of superconducting magnet system for large fusion reactors is described in this report. Instead of winding large planar or multi-axis coils, as has been proposed in previous fusion reactor designs, the superconducting coils are made by joining together several prefabricated conductor sections. The joints can be unmade and sections removed if they fail. Conductor sections can be made at a factory and shipped to the reactor site for assembly. The conductor stress level in the assembled coil can be kept small by external support of the coil at a number of points along its perimeter, so that the magnetic forces are transmitted to an external warm reinforcement structure. This warm reinforcement structure can also be the primary containment for the fusion reactor, constructed similar to a PCRV (Prestressed Concrete Reactor Vessel) used in fission reactors. Low thermal conductivity, high strength supports are used to transfer the magnetic forces to the external reinforcement through a hydraulic system. The hydraulic supports are movable and can be programmed to accommodate thermal contraction and to minimize stress in the superconducting coil

  14. Demountable low stress high field toroidal field magnet system for tokamak fusion reactors

    International Nuclear Information System (INIS)

    Powell, J.; Hsieh, D.; Lehner, J.; Suenaga, M.

    1978-01-01

    A new type of superconducting magnet system for large fusion reactors is described. Instead of winding large planar or multi-axis coils, as has been proposed in previous fusion reactor designs, the superconducting coils are made by joining together several prefabricated conductor sections. The joints can be unmade and sections removed if they fail. Conductor sections can be made at a factory and shipped to the reactor site for assembly. The conductor stress level in the assembled coil can be kept small by external support of the coil at a number of points along its perimeter, so that the magnetic forces are transmitted to an external warm reinforcement structure. This warm reinforcement structure can also be the primary containment for the fusion reactor, constructed similar to a PCRV (Prestressed Concrete Reactor Vessel) used in fission reactors. Low thermal conductivity, high strength supports are used to transfer the magnetic forces to the external reinforcement through a hydraulic system. The hydraulic supports are movable and can be programmed to accommodate thermal contraction and to minimize stress in the superconducting coil. (author)

  15. Cardiovascular reactivity as a mechanism linking child trauma to adolescent psychopathology

    Science.gov (United States)

    Heleniak, Charlotte; McLaughlin, Katie A.; Ormel, Johan; Riese, Harriette

    2016-01-01

    Alterations in physiological reactivity to stress are argued to be central mechanisms linking adverse childhood environmental experiences to internalizing and externalizing psychopathology. Childhood trauma exposure may influence physiological reactivity to stress in distinct ways from other forms of childhood adversity. This study applied a novel theoretical model to investigate the impact of childhood trauma on cardiovascular stress reactivity – the biopsychosocial model of challenge and threat. This model suggests that inefficient cardiovascular responses to stress – a threat as opposed to challenge profile – are characterized by blunted cardiac output (CO) reactivity and increased vascular resistance. We examined whether childhood trauma exposure predicted an indicator of the threat profile of cardiovascular reactivity and whether such a pattern was associated with adolescent psychopathology in a population-representative sample of 488 adolescents (M = 16.17 years old, 49.2% boys) in the TRacking Adolescents’ Individual Lives Survey (TRAILS). Exposure to trauma was associated with both internalizing and externalizing symptoms and a pattern of cardiovascular reactivity consistent with the threat profile, including blunted CO reactivity during a social stress task. Blunted CO reactivity, in turn, was positively associated with externalizing, but not internalizing symptoms and mediated the link between trauma and externalizing psychopathology. None of these associations varied by gender. The biopsychosocial model of challenge and threat provides a novel theoretical framework for understanding disruptions in physiological reactivity to stress following childhood trauma exposure, revealing a potential pathway linking such exposure with externalizing problems in adolescents. PMID:27568327

  16. The sex differences in nature of vascular endothelial stress: nitrergic mechanisms

    Science.gov (United States)

    Sindeev, Sergey; Gekaluyk, Artem; Ulanova, Maria; Agranovich, Ilana; Sharref, Ali Esmat; Semyachkina-Glushkovskaya, Oxana

    2016-04-01

    Here we studied the role of nitric oxide in cardiovascular regulation in male and female hypertensive rats under normal and stress conditions. We found that the severity of hypertension in females was lower than in males. Hypertensive females demonstrated more favorable pattern of cardiovascular responses to stress. Nitric oxide blockade by NG-nitro-L-arginine methyl ester (L-NAME) increased the mean arterial pressure and decreased the heart rate more effectively in females than in males. During stress, L-NAME modified the stress-induced cardiovascular responses more significantly in female compared with male groups. Our data show that hypertensive females demonstrated the more effective nitric oxide control of cardiovascular activity under normal and especially stress conditions than male groups. This sex differences may be important mechanism underlying greater in females vs. males stress-resistance of cardiovascular system and hypertension formation.

  17. Development of the apparatus for measuring magnetic properties of electrical steel sheets in arbitrary directions under compressive stress normal to their surface

    Science.gov (United States)

    Maeda, Yoshitaka; Urata, Shinya; Nakai, Hideo; Takeuchi, Yuuya; Yun, Kyyoul; Yanase, Shunji; Okazaki, Yasuo

    2017-05-01

    In designing motors, one must grasp the magnetic properties of electrical steel sheets considering actual conditions in motors. Especially important is grasping the stress dependence of magnetic power loss. This paper describes a newly developed apparatus to measure two-dimensional (2-D) magnetic properties (properties under the arbitrary alternating and the rotating flux conditions) of electrical steel sheets under compressive stress normal to the sheet surface. The apparatus has a 2-D magnetic excitation circuit to generate magnetic fields in arbitrary directions in the evaluation area. It also has a pressing unit to apply compressive stress normal to the sheet surface. During measurement, it is important to apply uniform stress throughout the evaluation area. Therefore, we have developed a new flux density sensor using needle probe method. It is composed of thin copper foils sputtered on electrical steel sheets. By using this sensor, the stress can be applied to the surface of the specimen without influence of this sensor. This paper described the details of newly developed apparatus with this sensor, and measurement results of iron loss by using are shown.

  18. “Soldier’s Heart”: A Genetic Basis for Elevated Cardiovascular Disease Risk Associated with Post-traumatic Stress Disorder

    Directory of Open Access Journals (Sweden)

    Harvey B. Pollard

    2016-09-01

    Full Text Available Soldier’s Heart, is an American Civil War term linking post-traumatic stress disorder (PTSD with increased propensity for cardiovascular disease (CVD. We have hypothesized that there might be a quantifiable genetic basis for this linkage. To test this hypothesis we identified a comprehensive set of candidate risk genes for PTSD, and tested whether any were also independent risk genes for CVD. A functional analysis algorithm was used to identify associated signaling networks.We identified 106 PTSD studies that report one or more polymorphic variants in 87 candidate genes in 83,463 subjects and controls. The top upstream drivers for these PTSD risk genes are predicted to be the glucocorticoid receptor (NR3C1 and Tumor Necrosis Factor alpha (TNFA. We find that 37 of the PTSD candidate risk genes are also candidate independent risk genes for CVD. The association between PTSD and CVD is significant by Fisher’s Exact Test (P= 3*10-54. We also find 15 PTSD risk genes that are independently associated with Type 2 Diabetes Mellitus (T2DM; also significant by Fisher’s Exact Test (P= 1.8*10-16. Our findings offer quantitative evidence for a genetic link between post-traumatic stress and cardiovascular disease, Computationally, the common mechanism for this linkage between PTSD and CVD is innate immunity and NFκB-mediated inflammation.

  19. Tunability of band structures in a two-dimensional magnetostrictive phononic crystal plate with stress and magnetic loadings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shunzu; Shi, Yang [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Gao, Yuanwen, E-mail: ywgao@lzu.edu.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2017-03-26

    Considering the magneto-mechanical coupling of magnetostrictive material, the tunability of in-plane wave propagation in two-dimensional Terfenol-D/epoxy phononic crystal (PC) plate is investigated theoretically by the plane wave expansion method. Two Schemes, i.e. magnetic field is rotated in x–y plane and x–z plane, are studied, respectively. The effects of amplitude and direction of magnetic field, pre-stress and geometric parameters are discussed. For Scheme-I, band gap reaches the maximum at an optimal angle 45° of magnetic field. However, the optimal angle is 0° for Scheme-II, because band gap decreases monotonically until disappears with the increasing angle. For both cases, higher-order band gaps generate and become stronger as magnetic field amplitude increases, while increasing compressive pre-stress has the opposite effect. Meanwhile, filling fraction plays a key role in controlling band gaps. These results provide possibility for intelligent regulation and optimal design of PC plates. - Highlights: • The in-plane wave propagation in phononic crystal thin plate is tuned theoretically. • Magnetostrictive material is introduced in the study. • The effects of magnetic field and pre-stress are considered. • The variations of band gaps with external stimuli are discussed.

  20. Stress analysis studies in optimised 'D' shaped TOKAMAK magnet designs

    International Nuclear Information System (INIS)

    Diserens, N.J.

    1975-07-01

    A suite of computer programs TOK was developed which enabled simple data input to be used for computation of magnetic fields and forces in a toroidal system of coils with either D-shaped or circular cross section. An additional requirement was that input data to the Swansea stress analysis program FINESSE could be output from the TOK fields and forces program, and that graphical output from either program should be available. A further program was required to optimise the coil shape. This used the field calculating routines from the TOK program. The starting point for these studies was the proposed 40 coil Princeton design. The stresses resulting from three different shapes of D-coil were compared. (author)

  1. [Burnout syndrome: a "true" cardiovascular risk factor].

    Science.gov (United States)

    Cursoux, Pauline; Lehucher-Michel, Marie-Pascale; Marchetti, Hélène; Chaumet, Guillaume; Delliaux, Stéphane

    2012-11-01

    The burnout syndrome is characterized by emotional exhaustion, depersonalization and reduced personal accomplishment in individuals professionally involved with others. The burnout syndrome is poorly recognized, particularly in France, as a distinct nosology from adaptation troubles, stress, depression, or anxiety. Several tools quantifying burnout and emotional exhaustion exist, the most spread is the questionnaire called Maslach Burnout Inventory. The burnout syndrome alters cardiovascular function and its neuroregulation by autonomic nervous system and is associated with: increased sympathetic tone to heart and vessels after mental stress, lowered physiological post-stress vagal rebound to heart, and lowered arterial baroreflex sensitivity. Job strain as burnout syndrome seems to be a real independent cardiovascular risk factor. Oppositely, training to manage emotions could increase vagal tone to heart and should be cardio-protective. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  2. Music can facilitate blood pressure recovery from stress.

    Science.gov (United States)

    Chafin, Sky; Roy, Michael; Gerin, William; Christenfeld, Nicholas

    2004-09-01

    Interventions that reduce the magnitude of cardiovascular responses to stress are justified, at least in part, by the notion that exaggerated responses to stress can damage the cardiovascular system. Recent data suggest that it is worthwhile to explore, in addition to the magnitude of the cardiovascular responses during stress (reactivity), the factors that affect the return to baseline levels after the stressor has ended (recovery). This experiment examined the effect of listening to music on cardiovascular recovery. Participants (N = 75) performed a challenging three-minute mental arithmetic task and then were assigned randomly to sit in silence or to listen to one of several styles of music: classical, jazz or pop. Participants who listened to classical music had significantly lower post-task systolic blood pressure levels (M = 2.1 mmHg above pre-stress baseline) than did participants who heard no music (M = 10.8 mmHg). Other musical styles did not produce significantly better recovery than silence. The data suggest that listening to music may serve to improve cardiovascular recovery from stress, although not all music selections are effective.

  3. Impact of Diabetes on Cardiovascular Disease: An Update

    Directory of Open Access Journals (Sweden)

    Alessandra Saldanha de Mattos Matheus

    2013-01-01

    Full Text Available Cardiovascular diseases are the most prevalent cause of morbidity and mortality among patients with type 1 or type 2 diabetes. The proposed mechanisms that can link accelerated atherosclerosis and increased cardiovascular risk in this population are poorly understood. It has been suggested that an association between hyperglycemia and intracellular metabolic changes can result in oxidative stress, low-grade inflammation, and endothelial dysfunction. Recently, epigenetic factors by different types of reactions are known to be responsible for the interaction between genes and environment and for this reason can also account for the association between diabetes and cardiovascular disease. The impact of clinical factors that may coexist with diabetes such as obesity, dyslipidemia, and hypertension are also discussed. Furthermore, evidence that justify screening for subclinical atherosclerosis in asymptomatic patients is controversial and is also matter of this review. The purpose of this paper is to describe the association between poor glycemic control, oxidative stress, markers of insulin resistance, and of low-grade inflammation that have been suggested as putative factors linking diabetes and cardiovascular disease.

  4. Left ventricular long axis function assessed during cine-cardiovascular magnetic resonance is an independent predictor of adverse cardiac events.

    Science.gov (United States)

    Rangarajan, Vibhav; Chacko, Satish Jacob; Romano, Simone; Jue, Jennifer; Jariwala, Nikhil; Chung, Jaehoon; Farzaneh-Far, Afshin

    2016-06-07

    Left ventricular pump function requires a complex interplay involving myocardial fibers orientated in the longitudinal, oblique and circumferential directions. Long axis dysfunction appears to be an early marker for a number of pathological states. We hypothesized that mitral annular plane systolic excursion (MAPSE) measured during cine-cardiovascular magnetic resonance (CMR) reflects changes in long axis function and may be an early marker for adverse cardiovascular outcomes. The aims of this study were therefore: 1) To assess the feasibility and reproducibility of MAPSE measurements during routine cine-CMR; and 2) To assess whether MAPSE, as a surrogate for long axis function, is a predictor of major adverse cardiovascular events (MACE). Four hundred consecutive patients undergoing CMR were prospectively enrolled. MAPSE was measured in the 4-chamber cine view. Patients were prospectively followed for major adverse cardiac events (MACE) - death, non-fatal myocardial infarction, hospitalization for heart failure or unstable angina, and late revascularization. Cox proportional hazards regression modeling was used to identify factors independently associated with MACE. Net reclassification improvement (NRI) was calculated to assess whether addition of MAPSE resulted in improved risk reclassification of MACE. Seventy-two MACE occurred during a median follow-up of 14.5 months. By Kaplan-Meier analysis, patients with lateral MAPSE cine-CMR is an independent predictor of MACE.

  5. Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents.

    Science.gov (United States)

    Eisenmann, Eric D; Rorabaugh, Boyd R; Zoladz, Phillip R

    2016-01-01

    Cardiovascular disease (CVD) is the largest cause of mortality worldwide, and stress is a significant contributor to the development of CVD. The relationship between acute and chronic stress and CVD is well evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury (IRI). Conversely, chronic stress is arrhythmogenic and increases sensitivity to myocardial IRI. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions.

  6. Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents

    Science.gov (United States)

    Eisenmann, Eric D.; Rorabaugh, Boyd R.; Zoladz, Phillip R.

    2016-01-01

    Cardiovascular disease (CVD) is the largest cause of mortality worldwide, and stress is a significant contributor to the development of CVD. The relationship between acute and chronic stress and CVD is well evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia–reperfusion injury (IRI). Conversely, chronic stress is arrhythmogenic and increases sensitivity to myocardial IRI. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions. PMID:27199778

  7. Visualization of coronary venous anatomy by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Crean Andrew

    2009-08-01

    Full Text Available Abstract Background Coronary venous imaging with whole-heart cardiovascular magnetic resonance (CMR angiography has recently been described using developmental pulse sequences and intravascular contrast agents. However, the practical utility of coronary venous imaging will be for patients with heart failure in whom cardiac resynchronisation therapy (CRT is being considered. As such complementary information on ventricular function and myocardial viability will be required. The aim of this study was to determine if the coronary venous anatomy could be depicted as part of a comprehensive CMR protocol and using a standard extracellular contrast agent. Methods and Results Thirty-one 3D whole heart CMR studies, performed after intravenous administration of 0.05 mmol/kg gadolinium DTPA, were reviewed. The cardiac venous system was visualized in all patients. The lateral vein of the left ventricle was present in 74%, the anterior interventricular vein in 65%, and the posterior interventricular vein in 74% of patients. The mean maximum distance of demonstrable cardiac vein on the 3D images was 81.5 mm and was dependent on the quality of the 3D data set. Five patients showed evidence of myocardial infarction on late gadolinium enhancement (LGE images. Conclusion Coronary venous anatomy can be reliably demonstrated using a comprehensive CMR protocol and a standard extracellular contrast agent. The combination of coronary venous imaging, assessment of ventricular function and LGE may be useful in the management of patients with LV dysfunction being considered for CRT.

  8. Modeling the effect of the stress demagnetization phenomenon on the magnetic properties in a no Fe-Si 3% sheet

    Directory of Open Access Journals (Sweden)

    Yakhlef Malika

    2015-01-01

    Full Text Available The aim of this paper is the modeling of the stress demagnetization effect on the magnetic properties in a non-oriented Fe-Si 3% sheet under different external stresses. The magneto-mechanical model used for magnetic hysteresis is based on a model originally formulated by Sablik-Jiles-Atherthon (S.J.A.. This latter has been modified by including both the stress demagnetization factor and the eddy current effects. The influence of the stress demagnetization term SDT on the magnetostrictive behavior of the material is also modeled. The proposed model has been validated by extensive simulations at different stresses, namely compressive and tensile stresses. Simulation results obtained by this model are very close to those published in the literature. Using the proposed model, very satisfactory performance has been achieved.

  9. Predator-based psychosocial stress animal model of PTSD: Preclinical assessment of traumatic stress at cognitive, hormonal, pharmacological, cardiovascular and epigenetic levels of analysis.

    Science.gov (United States)

    Zoladz, Phillip R; Diamond, David M

    2016-10-01

    Research on post-traumatic stress disorder (PTSD) is faced with the challenge of understanding how a traumatic experience produces long-lasting detrimental effects on behavior and brain functioning, and more globally, how stress exacerbates somatic disorders, including cardiovascular disease. Moreover, the design of translational research needs to link animal models of PTSD to clinically relevant risk factors which address why only a subset of traumatized individuals develop persistent psychopathology. In this review, we have summarized our psychosocial stress rodent model of PTSD which is based on well-described PTSD-inducing risk factors, including a life-threatening experience, a sense of horror and uncontrollability, and insufficient social support. Specifically, our animal model of PTSD integrates acute episodes of inescapable exposure of immobilized rats to a predator with chronic daily social instability. This stress regimen produces PTSD-like effects in rats at behavioral, cognitive, physiological, pharmacological and epigenetic levels of analysis. We have discussed a recent extension of our animal model of PTSD in which stress exacerbated coronary pathology following an ischemic event, assessed in vitro. In addition, we have reviewed our research investigating pharmacological and non-pharmacological therapeutic strategies which may have value in clinical approaches toward the treatment of traumatized people. Overall, our translational approach bridges the gap between human and animal PTSD research to create a framework with which to enhance our understanding of the biological basis of trauma-induced pathology and to assess therapeutic approaches in the treatment of psychopathology. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Socioeconomic Status and Cardiovascular Responses to Standardized Stressors: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Boylan, Jennifer Morozink; Cundiff, Jenny M; Matthews, Karen A

    2018-04-01

    Disparities in cardiovascular health by socioeconomic status (SES) are a pressing public health concern. Hypothesized mechanisms linking low SES to poor health are large cardiovascular responses to and delayed recovery from psychological stress. The current study presents a meta-analysis of the literature on the association of SES with blood pressure and heart rate reactivity to and recovery from acute stress tasks. The PubMed database was searched, and 26 unique studies with relevant data were identified (k = 25 reactivity [n = 14,617], k = 6 recovery [n = 1,324]). Using random-effects models, no significant association between SES and cardiovascular reactivity to stress emerged (r = .008, 95% confidence interval = -.02 to .04), although higher SES was associated with better recovery from stress (r = -.14, 95% confidence interval -.23 to -.05). Stressor type moderated the reactivity effect, wherein higher SES was associated with greater reactivity to cognitive stressors (r = .036, p = .024), not with reactivity to interpersonal stressors (r = -.02, p = .62), but was associated with lower reactivity to tasks with combinations of cognitive, interpersonal, and physical challenges (r = -.12, p = .029). Accounting for publication bias revealed a significant association between SES and reactivity in the opposite direction of hypotheses. Cardiovascular recovery from acute stress, but not reactivity to stress, may be a key pathway between low SES and risk for cardiovascular diseases. Heterogeneity in effect size and direction, challenges related to working across temporal dynamics, and recommendations for future research are discussed.

  11. Role of late gadolinium enhancement cardiovascular magnetic resonance in the risk stratification of hypertrophic cardiomyopathy.

    Science.gov (United States)

    Ismail, Tevfik F; Jabbour, Andrew; Gulati, Ankur; Mallorie, Amy; Raza, Sadaf; Cowling, Thomas E; Das, Bibek; Khwaja, Jahanzaib; Alpendurada, Francisco D; Wage, Ricardo; Roughton, Michael; McKenna, William J; Moon, James C; Varnava, Amanda; Shakespeare, Carl; Cowie, Martin R; Cook, Stuart A; Elliott, Perry; O'Hanlon, Rory; Pennell, Dudley J; Prasad, Sanjay K

    2014-12-01

    Myocardial fibrosis identified by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM) is associated with adverse cardiovascular events, but its value as an independent risk factor for sudden cardiac death (SCD) is unknown. We investigated the role of LGE-CMR in the risk stratification of HCM. We conducted a prospective cohort study in a tertiary referral centre. Consecutive patients with HCM (n=711, median age 56.3 years, IQR 46.7-66.6; 70.0% male) underwent LGE-CMR and were followed for a median 3.5 years. The primary end point was SCD or aborted SCD. Overall, 471 patients (66.2%) had myocardial fibrosis (median 5.9% of left ventricular mass, IQR: 2.2-13.3). Twenty-two (3.1%) reached the primary end point. The extent but not the presence of fibrosis was a significant univariable predictor of the primary end point (HR per 5% LGE: 1.24, 95% CI 1.06 to 1.45; p=0.007 and HR for LGE: 2.69, 95% CI 0.91 to 7.97; p=0.073, respectively). However, on multivariable analysis, only LV-EF remained statistically significant (HR: 0.92, 95% CI 0.89 to 0.95; p<0.001). For the secondary outcome of cardiovascular mortality/aborted SCD, the presence and the amount of fibrosis were significant predictors on univariable but not multivariable analysis after adjusting for LV-EF and non-sustained ventricular tachycardia. The amount of myocardial fibrosis was a strong univariable predictor of SCD risk. However, this effect was not maintained after adjusting for LV-EF. Further work is required to elucidate the interrelationship between fibrosis and traditional predictors of outcome in HCM. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. Systemic right ventricular fibrosis detected by cardiovascular magnetic resonance is associated with clinical outcome, mainly new-onset atrial arrhythmia, in patients after atrial redirection surgery for transposition of the great arteries.

    Science.gov (United States)

    Rydman, Riikka; Gatzoulis, Michael A; Ho, Siew Yen; Ernst, Sabine; Swan, Lorna; Li, Wei; Wong, Tom; Sheppard, Mary; McCarthy, Karen P; Roughton, Michael; Kilner, Philip J; Pennell, Dudley J; Babu-Narayan, Sonya V

    2015-05-01

    We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance predicts outcomes in patients with transposition of the great arteries post atrial redirection surgery. These patients have a systemic right ventricle (RV) and are at risk of arrhythmia, premature RV failure, and sudden death. Fifty-five patients (aged 27±7 years) underwent LGE cardiovascular magnetic resonance and were followed for a median 7.8 (interquartile range, 3.8-9.6) years in a prospective single-center cohort study. RV LGE was present in 31 (56%) patients. The prespecified composite clinical end point comprised new-onset sustained tachyarrhythmia (atrial/ventricular) or decompensated heart failure admission/transplantation/death. Univariate predictors of the composite end point (n=22 patients; 19 atrial/2 ventricular tachyarrhythmia, 1 death) included RV LGE presence and extent, RV volumes/mass/ejection fraction, right atrial area, peak Vo(2), and age at repair. In bivariate analysis, RV LGE presence was independently associated with the composite end point (hazard ratio, 4.95 [95% confidence interval, 1.60-15.28]; P=0.005), and only percent predicted peak Vo(2) remained significantly associated with cardiac events after controlling for RV LGE (hazard ratio, 0.80 [95% confidence interval, 0.68-0.95]; P=0.009/5%). In 8 of 9 patients with >1 event, atrial tachyarrhythmia, itself a known risk factor for mortality, occurred first. There was agreement between location and extent of RV LGE at in vivo cardiovascular magnetic resonance and histologically documented focal RV fibrosis in an explanted heart. There was RV LGE progression in a different case restudied for clinical indications. Systemic RV LGE is strongly associated with adverse clinical outcome especially arrhythmia in transposition of the great arteries, thus LGE cardiovascular magnetic resonance should be incorporated in risk stratification of these patients. © 2015 American Heart

  13. Effects of acupuncture on behavioral, cardiovascular and hormonal responses in restraint-stressed Wistar rats

    Directory of Open Access Journals (Sweden)

    Guimarães C.M.

    1997-01-01

    Full Text Available Stress is a well-known entity and may be defined as a threat to the homeostasis of a being. In the present study, we evaluated the effects of acupuncture on the physiological responses induced by restraint stress. Acupuncture is an ancient therapeutic technique which is used in the treatment and prevention of diseases. Its proposed mechanisms of action are based on the principle of homeostasis. Adult male Wistar EPM-1 rats were divided into four groups: group I (N = 12, unrestrained rats with cannulas previously implanted into their femoral arteries for blood pressure and heart rate measurements; group II (N = 12, rats that were also cannulated and were submitted to 60-min immobilization; group III (N = 12, same as group II but with acupuncture needles implanted at points SP6, S36, REN17, P6 and DU20 during the immobilization period; group IV (N = 14, same as group III but with needles implanted at points not related to acupuncture (non-acupoints. During the 60-min immobilization period animals were assessed for stress-related behaviors, heart rate, blood pressure and plasma corticosterone, noradrenaline and adrenaline levels. Group III animals showed a significant reduction (60% on average, P<0.02 in restraint-induced behaviors when compared to groups II and IV. Data from cardiovascular and hormonal assessments indicated no differences between group III and group II and IV animals, but tended to be lower (50% reduction on average in group I animals. We hypothesize that acupuncture at points SP6, S36, REN17, P6 and DU20 has an anxiolytic effect on restraint-induced stress that is not due to a sedative action

  14. Free Radicals and Antioxidants in Cardiovascular Health and Disease

    African Journals Online (AJOL)

    Free radicals can be overproduced or the natural antioxidant system defenses weakened, first resulting in oxidative stress, and then leading to oxidative injury ... Keywords: Oxidative stress, cardiovascular disease, atherosclerosis, inflammation, cell signaling and transduction mechanisms, antioxidants, dietary phenolics.

  15. Sumoylation of IkB attenuates NF-kB-induced nitrosative stress at rostral ventrolateral medulla and cardiovascular depression in experimental brain death.

    Science.gov (United States)

    Tsai, Ching-Yi; Li, Faith C H; Wu, Carol H Y; Chang, Alice Y W; Chan, Samuel H H

    2016-09-22

    Small ubiquitin-related modifier (SUMO) is a group of proteins that participates in post-translational modifications. One known SUMO target is the transcription factor nuclear factor-kB (NF-kB) that plays a pivotal role in many disease processes; sumoylation inactivates NF-kB by conjugation with inhibitors of NF-kB (IkB). Our laboratory demonstrated previously that transcriptional upregulation of nitric oxide synthase II (NOS II) by NF-kB, leading to nitrosative stress by the formation of peroxynitrite in the rostral ventrolateral medulla (RVLM), underpins the defunct brain stem cardiovascular regulation that precedes brain death. Based on an experimental endotoxemia model, this study evaluated the hypothesis that sumoylation plays a pro-life role in brain death by interacting with the NF-kB/NOS II/peroxynitrite signaling pathway in the RVLM. In Sprague-Dawley rats, intravenous administration of Escherichia coli lipopolysaccharide (LPS; 10 mg kg -1 ) elicited an augmentation of SUMO-1 and ubiquitin-conjugase 9 (Ubc9) mRNA or protein levels, alongside SUMO-1-conjugated proteins in the RVLM. Immunoneutralization of SUMO-1 or Ubc9 in the RVLM significantly potentiated the already diminished sumoylation of IkBα and intensified NF-kB activation and NOS II/peroxynitrite expression in this brain stem substrate, together with exacerbated fatality, cardiovascular depression and reduction of an experimental index of a life-and-death signal detected from arterial pressure that disappears in comatose patients signifying failure of brain stem cardiovascular regulation before brain death. We conclude that sumoylation of IkB in the RVLM ameliorates the defunct brain stem cardiovascular regulation that underpins brain death in our experimental endotoxemia modal by reducing nitrosative stress via inhibition of IkB degradation that diminishes the induction of the NF-kB/NOS II/peroxynitrite signaling cascade.

  16. Loneliness, Social Isolation, and Cardiovascular Health.

    Science.gov (United States)

    Xia, Ning; Li, Huige

    2018-03-20

    Social and demographic changes have led to an increased prevalence of loneliness and social isolation in modern society. Recent Advances: Population-based studies have demonstrated that both objective social isolation and the perception of social isolation (loneliness) are correlated with a higher risk of mortality and that both are clearly risk factors for cardiovascular disease (CVD). Lonely individuals have increased peripheral vascular resistance and elevated blood pressure. Socially isolated animals develop more atherosclerosis than those housed in groups. Molecular mechanisms responsible for the increased cardiovascular risk are poorly understood. In recent reports, loneliness and social stress were associated with activation of the hypothalamic-pituitary-adrenocortical axis and the sympathetic nervous system. Repeated and chronic social stress leads to glucocorticoid resistance, enhanced myelopoiesis, upregulated proinflammatory gene expression, and oxidative stress. However, the causal role of these mechanisms in the development of loneliness-associated CVD remains unclear. Elucidation of the molecular mechanisms of how CVD is induced by loneliness and social isolation requires additional studies. Understanding of the pathomechanisms is essential for the development of therapeutic strategies to prevent the detrimental effects of social stress on health. Antioxid. Redox Signal. 28, 837-851.

  17. Development of the apparatus for measuring magnetic properties of electrical steel sheets in arbitrary directions under compressive stress normal to their surface

    Directory of Open Access Journals (Sweden)

    Yoshitaka Maeda

    2017-05-01

    Full Text Available In designing motors, one must grasp the magnetic properties of electrical steel sheets considering actual conditions in motors. Especially important is grasping the stress dependence of magnetic power loss. This paper describes a newly developed apparatus to measure two-dimensional (2-D magnetic properties (properties under the arbitrary alternating and the rotating flux conditions of electrical steel sheets under compressive stress normal to the sheet surface. The apparatus has a 2-D magnetic excitation circuit to generate magnetic fields in arbitrary directions in the evaluation area. It also has a pressing unit to apply compressive stress normal to the sheet surface. During measurement, it is important to apply uniform stress throughout the evaluation area. Therefore, we have developed a new flux density sensor using needle probe method. It is composed of thin copper foils sputtered on electrical steel sheets. By using this sensor, the stress can be applied to the surface of the specimen without influence of this sensor. This paper described the details of newly developed apparatus with this sensor, and measurement results of iron loss by using are shown.

  18. Prognostic Value of Quantitative Stress Perfusion Cardiac Magnetic Resonance.

    Science.gov (United States)

    Sammut, Eva C; Villa, Adriana D M; Di Giovine, Gabriella; Dancy, Luke; Bosio, Filippo; Gibbs, Thomas; Jeyabraba, Swarna; Schwenke, Susanne; Williams, Steven E; Marber, Michael; Alfakih, Khaled; Ismail, Tevfik F; Razavi, Reza; Chiribiri, Amedeo

    2018-05-01

    This study sought to evaluate the prognostic usefulness of visual and quantitative perfusion cardiac magnetic resonance (CMR) ischemic burden in an unselected group of patients and to assess the validity of consensus-based ischemic burden thresholds extrapolated from nuclear studies. There are limited data on the prognostic value of assessing myocardial ischemic burden by CMR, and there are none using quantitative perfusion analysis. Patients with suspected coronary artery disease referred for adenosine-stress perfusion CMR were included (n = 395; 70% male; age 58 ± 13 years). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, aborted sudden death, and revascularization after 90 days. Perfusion scans were assessed visually and with quantitative analysis. Cross-validated Cox regression analysis and net reclassification improvement were used to assess the incremental prognostic value of visual or quantitative perfusion analysis over a baseline clinical model, initially as continuous covariates, then using accepted thresholds of ≥2 segments or ≥10% myocardium. After a median 460 days (interquartile range: 190 to 869 days) follow-up, 52 patients reached the primary endpoint. At 2 years, the addition of ischemic burden was found to increase prognostic value over a baseline model of age, sex, and late gadolinium enhancement (baseline model area under the curve [AUC]: 0.75; visual AUC: 0.84; quantitative AUC: 0.85). Dichotomized quantitative ischemic burden performed better than visual assessment (net reclassification improvement 0.043 vs. 0.003 against baseline model). This study was the first to address the prognostic benefit of quantitative analysis of perfusion CMR and to support the use of consensus-based ischemic burden thresholds by perfusion CMR for prognostic evaluation of patients with suspected coronary artery disease. Quantitative analysis provided incremental prognostic value to visual assessment and

  19. Coercivity and induced magnetic anisotropy by stress and/or field annealing in Fe- and Co- based (Finemet-type) amorphous alloys

    International Nuclear Information System (INIS)

    Miguel, C.; Zhukov, A.; Val, J.J. del; Gonzalez, J.

    2005-01-01

    Uniaxial magnetic anisotropy has been induced in amorphous Fe 73.5 Cu 1 Nb 3 Si 15.5 B 7 (Fe-rich) and (Co 77 Si 13.5 B 9.5 ) 90 Fe 7 Nb 3 (Co-rich) ferromagnetic alloys by annealing under stress and/or magnetic field. Such anisotropy plays a crucial role on the magnetization process and, consequently, determine the future applications of these materials. The mechanisms involved on the origin of such induced magnetic anisotropy showed significant differences between Fe-rich and Co-rich amorphous alloys. This work provides a comparative study of the coercive field and induced magnetic anisotropy in Fe-rich and Co-rich (Finemet) amorphous alloys treated by stress and/or field

  20. NMR techniques in the study of cardiovascular structure and functions

    International Nuclear Information System (INIS)

    Osbakken, M.; Haselgrove, J.

    1987-01-01

    The chapter titles of this book are: Introduction to NMR Techniques;Theory of NMR Probe Design;Overview of Magnetic Resonance Imaging to Study the Cardiovascular System;Vascular Anatomy and Physiology Studied with NMR Techniques;Assessment of Myocardial Ischemia and Infarction by Nuclear Magnetic Resonance Imaging;The Use of MRI in Congenital Heart Disease;Cardiomyopathies and Myocarditis Studied with NMR Techniques;Determination of Myocardial Mechanical Function with Magnetic Resonance Imaging Techniques;Determination of Flow Using NMR Techniques;The Use of Contrast Agents in Cardiac MRI;Can Cardiovascular Disease Be Effectively Evaluated with NMR Spectroscopy? NMR Studies of ATP Synthesis Reactions in the Isolated Heart;Studies of Intermediary Metabolism in the Heart by 13C NMR Spectroscopy;23Na and 39K NMR Spectroscopic Studies of the Intact Beating Heart;and Evaluation of Skeletal Muscle Metabolism in Patients with Congestive Heart Failure Using Phosphorus Nuclear Magnetic Resonance

  1. Magnetic resonance imaging for stress incontinence: evaluation of patients before and after surgical correction

    Energy Technology Data Exchange (ETDEWEB)

    Perk, Hakki E-mail: hakkiperk@yahoo.com; Oral, Baha; Yesildag, Ahmet; Serel, T. Ahmet; Oezsoy, Mesut; Turgut, Tayfun

    2002-10-01

    Objective: The purpose of this study was to evaluate the accuracy of magnetic resonance imaging (MRI) in the pre and postoperative assessment of stress urinary incontinence. Methods: Fifteen female patients with clinical evidence of stress urinary incontinence were included in this prospective study. All the patients underwent MRI in the supine position both preoperatively and postoperatively. For imaging, we used a 1.0 T magnet, T2-weighted images were obtained in the midline sagittal plane with patients at rest. Images were evaluated for anatomical stress urinary incontinence alterations, such as the increased distance between the pubococcygeal line and the bladder base and the posterior urethro-vesical angle and the urethral inclination angle changes. Wilcoxon signed rank test allowed comparisons of pre and postoperative results. Results: Compared with postoperative measurements, the bladder base was lowered significantly by an average of 9.4{+-}4.0 mm (P<0.01), posterior urethro-vesical angle was significantly increased by an average of 127.8{+-}11.4 deg. (P<0.01), and the urethral inclination angle was significantly increased by an average of 54.9{+-}10.1 deg. (P<0.01) preoperatively. Conclusion: Our results suggest that MRI can play a major role in the preoperative and postoperative assessment of stress urinary incontinence. It can reliably detect anatomical urinary incontinence alterations. MRI should be considered in failed surgery, complex prolapse, and in differentiating genuine stress incontinence resulting from malposition of the bladder neck from stress incontinence due to intrinsic urethral damage.

  2. Sex and family history of cardiovascular disease influence heart rate variability during stress among healthy adults.

    Science.gov (United States)

    Emery, Charles F; Stoney, Catherine M; Thayer, Julian F; Williams, DeWayne; Bodine, Andrew

    2018-07-01

    Studies of sex differences in heart rate variability (HRV) typically have not accounted for the influence of family history (FH) of cardiovascular disease (CVD). This study evaluated sex differences in HRV response to speech stress among men and women (age range 30-49 years) with and without a documented FH of CVD. Participants were 77 adults (mean age = 39.8 ± 6.2 years; range: 30-49 years; 52% female) with positive FH (FH+, n = 32) and negative FH (FH-, n = 45) of CVD, verified with relatives of participants. Cardiac activity for all participants was recorded via electrocardiogram during a standardized speech stress task with three phases: 5-minute rest, 5-minute speech, and 5-minute recovery. Outcomes included time domain and frequency domain indicators of HRV and heart rate (HR) at rest and during stress. Data were analyzed with repeated measures analysis of variance, with sex and FH as between subject variables and time/phase as a within subject variable. Women exhibited higher HR than did men and greater HR reactivity in response to the speech stress. However, women also exhibited greater HRV in both the time and frequency domains. FH+ women generally exhibited elevated HRV, despite the elevated risk of CVD associated with FH+. Although women participants exhibited higher HR at rest and during stress, women (both FH+ and FH-) also exhibited elevated HRV reactivity, reflecting greater autonomic control. Thus, enhanced autonomic function observed in prior studies of HRV among women is also evident among FH+ women during a standardized stress task. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Identification and assessment of Anderson-Fabry disease by cardiovascular magnetic resonance noncontrast myocardial T1 mapping.

    Science.gov (United States)

    Sado, Daniel M; White, Steven K; Piechnik, Stefan K; Banypersad, Sanjay M; Treibel, Thomas; Captur, Gabriella; Fontana, Marianna; Maestrini, Viviana; Flett, Andrew S; Robson, Matthew D; Lachmann, Robin H; Murphy, Elaine; Mehta, Atul; Hughes, Derralynn; Neubauer, Stefan; Elliott, Perry M; Moon, James C

    2013-05-01

    Anderson-Fabry disease (AFD) is a rare but underdiagnosed intracellular lipid disorder that can cause left ventricular hypertrophy (LVH). Lipid is known to shorten the magnetic resonance imaging parameter T1. We hypothesized that noncontrast T1 mapping by cardiovascular magnetic resonance would provide a novel and useful measure in this disease with potential to detect early cardiac involvement and distinguish AFD LVH from other causes. Two hundred twenty-seven subjects were studied: patients with AFD (n=44; 55% with LVH), healthy volunteers (n=67; 0% with LVH), patients with hypertension (n=41; 24% with LVH), patients with hypertrophic cardiomyopathy (n=34; 100% with LVH), those with severe aortic stenosis (n=21; 81% with LVH), and patients with definite amyloid light-chain (AL) cardiac amyloidosis (n=20; 100% with LVH). T1 mapping was performed using the shortened modified Look-Locker inversion sequence on a 1.5-T magnet before gadolinium administration with primary results derived from the basal and midseptum. Compared with health volunteers, septal T1 was lower in AFD and higher in other diseases (AFD versus healthy volunteers versus other patients, 882±47, 968±32, 1018±74 milliseconds; Pgadolinium enhancement (1001±82 versus 891±38 milliseconds; P<0.0001). Noncontrast T1 mapping shows potential as a unique and powerful measurement in the imaging assessment of LVH and AFD.

  4. Novel processing of Barkhausen noise signal for assessment of residual stress in surface ground components exhibiting poor magnetic response

    International Nuclear Information System (INIS)

    Vashista, M.; Paul, S.

    2011-01-01

    The Barkhausen Noise Analysis (BNA) technique has been utilised to assess surface integrity of steels. But the BNA technique is not very successful in evaluating surface integrity of ground steels that exhibit poor micro-magnetic response. A new approach has been proposed for the processing of BN signal and two newly proposed parameters, namely 'count' and 'event', have been shown to correlate linearly with the residual stress upon grinding, with judicious choice of user defined 'threshold', even when the micro-magnetic response of the work material is poor. In the present study, residual stress induced upon conventional plunge surface grinding of hardened bearing steel has been investigated along with unhardened bearing steel for benchmarking. Moreover, similar correlation has been established, when primarily compressive stress is induced upon high speed grinding using cBN wheel with moderately deep cut suppressing the micro-magnetic response from the ground medium carbon steel as the work material. - Highlights: → The problem of work materials exhibiting poor BN response and poor Barkhausen Noise response is identified. → A novel signal processing strategy is introduced to address the issue of poor micro-magnetic response of some ferromagnetic material. → Potential of newly introduced BN parameters has been studied. → These two BN parameters exhibited linear correlation with residual stress for work material with poor micro-magnetic response.

  5. Does unconscious stress play a role in prolonged cardiovascular stress recovery?

    Science.gov (United States)

    Brosschot, J F; Geurts, S A E; Kruizinga, I; Radstaak, M; Verkuil, B; Quirin, M; Kompier, M A J

    2014-08-01

    According to recent insights, humans might not be aware of a substantial part of their cognitive stress representations while these still have prolonged physiological effects. 'Unconscious stress' can be measured by implicit affect (IA) tests. It was shown that IA predicts physiological stress responses, in fact better than explicit ('conscious') affect. It is not known yet whether IA is associated with concurrent prolonged stress responses. In two studies (n = 62 and 123), anger harassment was used to induce stress. Blood pressure (BP) and heart rate (HR) were measured continuously. During BP and HR recovery, IA was measured by an 'anger' version of the implicit association test (IAT) or the implicit positive and negative affect test (IPANAT). Blood pressure and HR increased during anger harassment and recovery afterwards. When using the IPANAT BP recovery levels were lower when positive IA was high and higher when negative IA was high, independent of explicit affect and rumination. These results were not found using the IAT. These results provide preliminary evidence that physiological stress recovery is associated with IA. This is in line with the theory that unconscious stress is responsible for a-possibly considerable-part of unhealthy prolonged stress-related physiological activity. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Total antioxidant capacity, total oxidant status and oxidative stress index in the men exposed to 1.5 T static magnetic field.

    Science.gov (United States)

    Sirmatel, O; Sert, C; Sirmatel, F; Selek, S; Yokus, B

    2007-06-01

    The aim of this study was to investigate the effects of a high-strength magnetic field produced by a magnetic resonance imaging (MRI) apparatus on oxidative stress. The effects of a 1.5 T static magnetic field on the total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) in male subjects were investigated. In this study, 33 male volunteers were exposed to a 1.5 T static magnetic field for a short time and the TAC, TOS and OSI of each subject were determined. Magnetic field exposure was provided using a magnetic resonance apparatus; radiofrequency was not applied. Blood samples were taken from subjects and TAC, TOS and OSI values were measured using the methods of Erel. TAC showed a significant increase in post-exposures compared to pre-exposures to the magnetic field (p < 0.05). OSI and TOS showed a significant decrease in post-exposures compared to pre-exposures to a 1.5 T magnetic field (for each of two, p < 0.01). The 1.5 T static magnetic field used in the MRI apparatus did not yield a negative effect; on the contrary, it produced the positive effect of decreasing oxidative stress in men following short-term exposure.

  7. Role of TRP channels in the cardiovascular system.

    Science.gov (United States)

    Yue, Zhichao; Xie, Jia; Yu, Albert S; Stock, Jonathan; Du, Jianyang; Yue, Lixia

    2015-02-01

    The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases. Copyright © 2015 the American Physiological Society.

  8. Does Unconscious Stress Play a Role in Prolonged Cardiovascular Stress Recovery?

    NARCIS (Netherlands)

    Brosschot, J.F.; Geurts, S.A.E.; Kruizinga, I.; Radstaak, M.; Verkuil, B.; Quirin, M.R.; Kompier, M.A.J.

    2014-01-01

    According to recent insights, humans might not be aware of a substantial part of their cognitive stress representations while these still have prolonged physiological effects. Unconscious stress' can be measured by implicit affect (IA) tests. It was shown that IA predicts physiological stress

  9. Test anxiety and cardiovascular responses to daily academic stressors.

    Science.gov (United States)

    Conley, Kristen M; Lehman, Barbara J

    2012-02-01

    Routine academic events may cause stress and produce temporary elevations in blood pressure. Students who experience test anxiety may be especially prone to cardiovascular activation in response to academic stress. This study drew on self-reported stress and ambulatory blood pressure measurements provided by 99 undergraduate participants (30% men, mean age=21 years) who participated over 4 days. Posture, activity level, recent consumption and the previous same-day reading were considered as covariates in a series of hierarchical linear models. Results indicate elevations in systolic blood pressure at times of acute academic stressors; neither diastolic blood pressure nor heart rate was linked with academic stress. In addition, those participants higher in test anxiety exhibited especially pronounced elevations in systolic blood pressure during times of acute academic stress. This research suggests that everyday academic stressors are linked with temporary increases in blood pressure and that test anxiety may contribute to these elevations. Test anxiety has implications for future academic and job success, and cardiovascular responses to everyday stress may contribute to health problems later in life. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Influence of stresses and magnetostriction on the soft magnetic behavior of metallic films

    NARCIS (Netherlands)

    Chezan, AR; Craus, CB; Chechenin, NG; Vystavel, T; Niesen, L; De Hosson, JTM; Boerma, DO

    Nanocrystalline soft magnetic Fe-Zr-N films have been successfully deposited by DC magnetron reactive sputtering. For thick films (>200 nm), the compressive stress in the as-deposited films and the positive matgnetostriction produce perpendicular anisotropy. The magnitude of this effect is smaller

  11. Generation of sheared poloidal flows by electrostatic and magnetic Reynolds stress in the boundary plasma of HT-7 tokamak

    International Nuclear Information System (INIS)

    Xu, G.S.; Wan, B.N.; Li, J.

    2005-01-01

    The radial profiles of electrostatic and magnetic Reynolds stress (Maxwell stress) have been measured in the plasma boundary region of HT-7 tokamak. Experimental results show that the radial gradient of electrostatic Reynolds stress (ERS) changes sign across the last closed flux surface, and the neoclassical flow damping and the damping due to charge exchange processes are balanced by the radial gradient of ERS, which sustains the equilibrium sheared flow structure in a steady state. The contribution of magnetic Reynolds stress was found unimportant in a low β plasma. Detailed analyses indicate that the propagation properties of turbulence in radial and poloidal directions and the profiles of potential fluctuation level are responsible for the radial structure of ERS. (author)

  12. Review of Journal of Cardiovascular Magnetic Resonance 2012

    Science.gov (United States)

    2013-01-01

    There were 90 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2012, which is an 8% increase in the number of articles since 2011. The quality of the submissions continues to increase. The editors are delighted to report that the 2011 JCMR Impact Factor (which is published in June 2012) has risen to 4.44, up from 3.72 for 2010 (as published in June 2011), a 20% increase. The 2011 impact factor means that the JCMR papers that were published in 2009 and 2010 were cited on average 4.44 times in 2011. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is approximately 25%, and has been falling as the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication. PMID:24006874

  13. Stresses evolution at high temperature (200°C on the interface of thin films in magnetic components

    Directory of Open Access Journals (Sweden)

    Doumit Nicole

    2014-07-01

    Full Text Available In the field of electronics, the increase of operating temperatures is a major industrial and scientific challenge because it allows reducing mass and volume of components especially in the aeronautic domain. So minimizing our components reduce masses and the use of cooling systems. For that, the behaviours and interface stresses of our components (in particular magnetic inductors and transformers that are constituted of one magnetic layer (YIG or an alumina substrate (Al2O3 representing the substrate and a thin copper film are studied at high temperature (200°C. COMSOL Multiphysics is used to simulate our work and to validate our measurements results. In this paper, we will present stresses results according to the geometrical copper parameters necessary for the component fabrication. Results show that stresses increase with temperature and copper’s thickness while remaining always lower than 200MPa which is the rupture stress value.

  14. Spatio-temporal structure of turbulent Reynolds stress zonal flow drive in 3D magnetic configuration

    International Nuclear Information System (INIS)

    Schmid, B; Ramisch, M; Manz, P; Stroth, U

    2017-01-01

    The poloidal dependence of the zonal flow drive and the underlying Reynolds stress structure are studied at the stellarator experiment TJ-K by means of a poloidal Langmuir-probe array. This gives the unique possibility to study the locality of the Reynolds stress in a complex toroidal magnetic geometry. It is found that the Reynolds stress is not homogeneously distributed along the flux surface but has a strong poloidal asymmetry where it is concentrated on the outboard side with a maximum above the midplane. The average tilt of the turbulent structures is thereby reflected in the anisotropy of the bivariant velocity distribution. Using a conditional averaging technique the temporal dynamics reveal that the zonal flow drive is also maximal in this particular region. The results suggest an influence of the magnetic field line curvature, which controls the underlying plasma turbulence. The findings are a basis for further comparison with turbulence simulations in 3D geometry and demonstrate the need for a global characterisation of plasma turbulence. (paper)

  15. NMR imaging of the cardiovascular system

    International Nuclear Information System (INIS)

    Canby, R.C.; Evanochko, W.T.; Pohost, G.M.

    1986-01-01

    Proton nuclear magnetic resonance (NMR) imaging permits high-resolution tomographic and three-dimensional images of the human body to be obtained without exposure to ionizing radiation. Such imaging not only yields anatomic resolution comparable to X-ray examinations but also provides a potential means to discriminate between healthy tissue and diseased tissue. This potential is based on certain NMR properties known as relaxation times, which determine, in part, the signal intensity in an image. These properties are related to such factors as the sizes and concentrations of proteins and mobile lipids and the compartmentalization of the protons of water. Although NMR imaging (also called magnetic resonance imaging, MRI) is becoming widely available for clinical use, application to the cardiovascular system, though promising, remains primarily a research tool. Gated proton NMR imaging can generate cardiac images with excellent morphologic detail and contrast; however, its ultimate importance as a cardiovascular diagnostic modality will depend on the development of several unique applications. These applications are discussed in this paper

  16. Velocity encoded cardiovascular magnetic resonance to assess left atrial appendage emptying

    Directory of Open Access Journals (Sweden)

    Muellerleile Kai

    2012-06-01

    Full Text Available Abstract Background The presence of impaired left atrial appendage (LAA function identifies patients who are prone to thrombus formation in the LAA and therefore being at high risk for subsequent cardioembolic stroke. LAA function is typically assessed by measurements of LAA emptying velocities using transesophageal echocardiography (TEE in clinical routine. This study aimed at evaluating the feasibility of assessing LAA emptying by velocity encoded (VENC cardiovascular magnetic resonance (CMR. Methods This study included 30 patients with sinus rhythm (n = 18 or atrial fibrillation (n = 12. VENC-CMR velocity measurements were performed perpendicular to the orifice of the LAA. Peak velocities were measured of passive diastolic LAA emptying (e-wave in all patients. Peak velocities of active, late-diastolic LAA emptying (a-wave were assessed in patients with sinus rhythm. Correlation and agreement was analyzed between VENC-CMR and TEE measurements of e- and a-wave peak velocities. Results A significant correlation and good agreement was found between VENC-CMR and TEE measurements of maximal e-wave velocities (r = 0.61, P  Conclusions The assessment of active and passive LAA emptying by VENC-CMR is feasible. Further evaluation is required of potential future clinical applications such as risk stratification for cardioembolic stroke.

  17. Evaluative threat and ambulatory blood pressure: cardiovascular effects of social stress in daily experience.

    Science.gov (United States)

    Smith, Timothy W; Birmingham, Wendy; Uchino, Bert N

    2012-11-01

    Physiological effects of social evaluation are central in models of psychosocial influences on physical health. Experimental manipulations of evaluative threat evoke substantial cardiovascular and neuroendocrine responses in laboratory studies, but only preliminary evidence is available regarding naturally occurring evaluative threats in daily life. In such nonexperimental ambulatory studies, it is essential to distinguish effects of evaluative threat from related constructs known to alter stress, such as ability perceptions and concerns about appearance. 94 married, working couples (mean age 29.2 years) completed a 1-day (8 a.m. to 10 p.m.) ambulatory blood pressure protocol with random interval-contingent measurements using a Suntech monitor and Palm Pilot-based measures of control variables and momentary experiences of social-evaluative threat, concerns about appearance, and perceived ability. In hierarchical analyses for couples and multiple measurement occasions (Proc Mixed; SAS) and controlling individual differences (BMI, age, income) and potential confounds (e.g., posture, activity), higher reports of social-evaluative threat were associated with higher concurrent systolic (estimate = .87, SE = .34) and diastolic blood pressure (estimate = 1.06; SE = .26), both p social-evaluative threat remained significant when perceived ability and appearance concerns were controlled. Naturally occurring social-evaluative threat during daily activity is associated with increased systolic and diastolic blood pressure. Given associations between ambulatory blood pressure and risk of cardiovascular disease, the findings support conceptual models of threats to the social self as a potentially important influence on physical health.

  18. Effect of stress relief annealing temperature and atmosphere on the magnetic properties of silicon steel

    International Nuclear Information System (INIS)

    Paolinelli, Sebastiao C.; Cunha, Marco A. da

    2006-01-01

    Fully processed non-oriented silicon steel samples 0.50 mm thick were sheared and submitted to stress relief annealing under different conditions of temperature and atmosphere to investigate the effect of this treatment on the recovery of magnetic properties. Two different compositions were used, with different Si and Al contents. Temperature was varied in the range of 600-900 deg. C and four atmospheres were used: N 2 and N 2 +10%H 2 combined with dew points of -10 and 15 deg. C. The results showed that annealing atmosphere has very important effect on the magnetic properties and that the beneficial effect of stress relief annealing can be overcome by the detrimental effect of the atmosphere under certain conditions, due to oxidation and nitration

  19. Abnormal ankle brachial indices may predict cardiovascular disease among diabetic patients without known heart disease.

    Science.gov (United States)

    Fine, Jeffrey J; Hopkins, Christie B; Hall, Patrick Ax

    2005-07-01

    Cardiovascular disease remains the primary cause of diabetes-associated morbidity and mortality. Previous studies have failed to provide accurate, inexpensive, screening techniques to detect cardiovascular disease in diabetics. Ankle brachial indices (ABI) testing may be an effective screening technique for diabetics. The aim of this 100-subject clinical study was to determine cardiovascular disease prevalence, via perfusion stress testing, in diabetic patients having abnormal ABI (<0.90) and without known heart disease who were referred to the South Carolina Heart Center, Columbia, SC for nuclear perfusion stress testing. Study data were analyzed using frequency and descriptive statistics and 2-sample T-testing. Mean subject age was 62+/-11 years, ABI 0.76+/-13, and ejection fraction 60+/-12%. Perfusion stress testing detected 49 abnormal electrocardiograms, 36 subjects with coronary ischemia, 20 with diminished left ventricular function, and 26 subjects having significant thinning of the myocardium. There were 71 subjects who tested positive for at least one form of cardiovascular disease. The sole predictive variable reaching significance for the presence of cardiovascular disease was an ABI score <0.90 (p< or =0.0001). Cardiovascular disease may be predicted among diabetic patients via ABI scores and confirmed by nuclear perfusion testing.

  20. Influence of tensile stress and frequency on the longitudinal magnetic hysteresis of amorphous wires

    International Nuclear Information System (INIS)

    Torres, Carlos; Maria Munoz, Jose; Hernandez-Gomez, Pablo; Francisco, Carlos de

    2010-01-01

    This work studies the longitudinal magnetic hysteresis of amorphous wires with different Fe or Co compositions through an external magnetic field in the axial direction. Measurements have been carried out with the help of a digitally processed system in the 50 Hz-1 kHz frequency range. In addition, the influence of different tensile stresses has been also analyzed. The results show that both parameters change considerably the magnetic hysteresis of the wires but in a different way depending on their composition. This behaviour has been interpreted in terms of the different domain distribution associated with the opposite sign of the magnetostriction for Fe and Co-based wires, respectively.

  1. Cardiac magnetic resonance imaging

    African Journals Online (AJOL)

    2011-03-06

    Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

  2. The effects of age on the spontaneous low-frequency oscillations in cerebral and systemic cardiovascular dynamics

    International Nuclear Information System (INIS)

    Peng, Tingying; Rowley, Alex B; Payne, Stephen J; Ainslie, Philip N; Murrell, Carissa; Thomas, Kate; Cotter, James D; Williams, Michael J A; George, Keith; Shave, Rob

    2008-01-01

    Although the effects of ageing on cardiovascular control and particularly the response to orthostatic stress have been the subject of many studies, the interaction between the cardiovascular and cerebral regulation mechanisms is still not fully understood. Wavelet cross-correlation is used here to assess the coupling and synchronization between low-frequency oscillations (LFOs) observed in cerebral hemodynamics, as measured using cerebral blood flow velocity (CBFV) and cerebral oxygenation (O 2 Hb), and systemic cardiovascular dynamics, as measured using heart rate (HR) and arterial blood pressure (ABP), in both old and young healthy subjects undergoing head-up tilt table testing. Statistically significant increases in correlation values are found in the interaction of cerebral and cardiovascular LFOs for young subjects (P 2 Hb and ABP–O 2 Hb), but not in old subjects under orthostatic stress. The coupling between the cerebrovascular and wider cardiovascular systems in response to orthostatic stress thus appears to be impaired with ageing

  3. Sirtuins in the Cardiovascular System: Potential Targets in Pediatric Cardiology.

    Science.gov (United States)

    Ianni, Alessandro; Yuan, Xuejun; Bober, Eva; Braun, Thomas

    2018-06-01

    Cardiovascular diseases represent a major cause of death and morbidity. Cardiac and vascular pathologies develop predominantly in the aged population in part due to lifelong exposure to numerous risk factors but are also found in children and during adolescence. In comparison to adults, much has to be learned about the molecular pathways driving cardiovascular diseases in the pediatric population. Sirtuins are highly conserved enzymes that play pivotal roles in ensuring cardiac homeostasis under physiological and stress conditions. In this review, we discuss novel findings about the biological functions of these molecules in the cardiovascular system and their possible involvement in pediatric cardiovascular diseases.

  4. Effects of pulsed magnetic field treatment of soybean seeds on calli growth, cell damage, and biochemical changes under salt stress.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Leelapriya, Thasari; Kumari, Bollipo Diana Ranjitha

    2012-12-01

    The effects of magnetic field (MF) treatments of soybean seeds on calli growth, cell damage, and biochemical changes under salt stress were investigated under controlled conditions. Soybean seeds were exposed to a 1.0 Hz sinusoidal uniform pulsed magnetic field (PMF) of 1.5 µT for 5 h/day for 20 days. Non-treated seeds were considered as controls. For callus regeneration, the embryonic axis explants were taken from seeds and inoculated in a saline medium with a concentration of 10 mM NaCl for calli growth analysis and biochemical changes. The combined treatment of MF and salt stress was found to significantly increase calli fresh weight, total soluble sugar, total protein, and total phenol contents, but it decreased the ascorbic acid, lipid peroxidation, and catalase activity of calli from magnetically exposed seeds compared to the control calli. PMF treatment significantly improved calli tolerance to salt stress in terms of an increase in flavonoid, flavone, flavonole, alkaloid, saponin, total polyphenol, genistein, and daidzein contents under salt stress. The results suggest that PMF treatment of soybean seeds has the potential to counteract the adverse effects of salt stress on calli growth by improving primary and secondary metabolites under salt stress conditions. Copyright © 2012 Wiley Periodicals, Inc.

  5. Application of magnetomechanical hysteresis modeling to magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Rollwitz, W.L.; Cadena, D.

    1992-01-01

    The objective is to investigate experimentally and theoretically the effects of neutron embrittlement and biaxial stress on magnetic properties in steels, using various magnetic measurement techniques. Interaction between experiment and modeling should suggest efficient magnetic measurement procedures for determining neutron embrittlement biaxial stress. This should ultimately assist in safety monitoring of nuclear power plants and of gas and oil pipelines. In the first six months of this first year study, magnetic measurements were made on steel surveillance specimens from the Indian Point 2 and D.C. Cook 2 reactors. The specimens previously had been characterized by Charpy tests after specified neutron fluences. Measurements now included: (1) hysteresis loop measurement of coercive force, permeability and remanence, (2) Barkhausen noise amplitude; and (3) higher order nonlinear harmonic analysis of a 1 Hz magnetic excitation. Very good correlation of magnetic parameters with fluence and embrittlement was found for specimens from the Indian Point 2 reactor. The D.C. Cook 2 specimens, however showed poor correlation. Possible contributing factors to this are: (1) metallurgical differences between D.C. Cook 2 and Indian Point 2 specimens; (2) statistical variations in embrittlement parameters for individual samples away from the stated men values; and (3) conversion of the D.C. Cook 2 reactor to a low leakage core configuration in the middle of the period of surveillance. Modeling using a magnetomechanical hysteresis model has begun. The modeling will first focus on why Barkhausen noise and nonlinear harmonic amplitudes appear to be better indicators of embrittlement than the hysteresis loop parameters

  6. Advances in cardiac magnetic resonance imaging of congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Driessen, Mieke M.P. [University of Utrecht, University Medical Center Utrecht, Department of Radiology, PO Box 85500, Utrecht (Netherlands); University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); The Interuniversity Cardiology Institute of the Netherlands (ICIN) - Netherlands Heart Institute, PO Box 19258, Utrecht (Netherlands); Breur, Johannes M.P.J. [Wilhelmina Children' s Hospital, University Medical Center Utrecht, Department of Pediatric Cardiology, PO Box 85500, Utrecht (Netherlands); Budde, Ricardo P.J.; Oorschot, Joep W.M. van; Leiner, Tim [University of Utrecht, University Medical Center Utrecht, Department of Radiology, PO Box 85500, Utrecht (Netherlands); Kimmenade, Roland R.J. van; Sieswerda, Gertjan Tj [University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); Meijboom, Folkert J. [University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); Wilhelmina Children' s Hospital, University Medical Center Utrecht, Department of Pediatric Cardiology, PO Box 85500, Utrecht (Netherlands)

    2015-01-01

    Due to advances in cardiac surgery, survival of patients with congenital heart disease has increased considerably during the past decades. Many of these patients require repeated cardiovascular magnetic resonance imaging to assess cardiac anatomy and function. In the past decade, technological advances have enabled faster and more robust cardiovascular magnetic resonance with improved image quality and spatial as well as temporal resolution. This review aims to provide an overview of advances in cardiovascular magnetic resonance hardware and acquisition techniques relevant to both pediatric and adult patients with congenital heart disease and discusses the techniques used to assess function, anatomy, flow and tissue characterization. (orig.)

  7. [Cardiovascular resistance to orthostatic stress in athletes after aerobic exercise].

    Science.gov (United States)

    Mel'nikov, A A; Popov, S G; Vikulov, A D

    2014-01-01

    In the paper cardiovascular resistance to orthostatic stress in the athletes in the two-hour recovery period after prolonged aerobic exercise was investigated. The reaction of the cardiac (stroke volume and cardiac output) and peripheral blood volumes in the lower and upper limbs, abdominal and neck regions in response to the tilt-test before and during two hours after exercise (30 min, heart rate = 156 +/- 8 beats/min) was determined by impedance method: It is found that: (1) at baseline distribution of blood flow in favor of the neck-region in response to the tilt-test, in spite of the decrease in cardiac output, was more efficient in athletes, that was due to a large decrease in blood flow to the lower extremities, and increased blood flow in the neck region; (2) after exercise it was established symptoms of potential orthostatic intolerance: postural hypotension and tachycardia, reduced peripheral pulse blood volume, expressed in a standing position, and reduced effectiveness of the distribution of blood flow in the direction of the neck region; (3) the abilityto effectively distribute blood flow in favor of the neck region in athletes after exercise remained elevated, which was due to a large decrease in blood flow in the abdominal region at the beginning, and in the lower limbs at the end of the recovery period.

  8. Surgical Robotics Research in Cardiovascular Disease

    Energy Technology Data Exchange (ETDEWEB)

    Pohost, Gerald M; Guthrie, Barton L; Steiner, Charles

    2008-02-29

    This grant is to support a research in robotics at three major medical centers: the University of Southern California-USC- (Project 1); the University of Alabama at Birmingham-UAB-(Project 2); and the Cleveland Clinic Foundation-CCF-(Project 3). Project 1 is oriented toward cardiovascular applications, while projects 2 and 3 are oriented toward neurosurgical applications. The main objective of Project 1 is to develop an approach to assist patients in maintaining a constant level of stress while undergoing magnetic resonance imaging or spectroscopy. The specific project is to use handgrip to detect the changes in high energy phosphate metabolism between rest and stress. The high energy phosphates, ATP and phosphocreatine (PCr) are responsible for the energy of the heart muscle (myocardium) responsible for its contractile function. If the blood supply to the myocardium in insufficient to support metabolism and contractility during stress, the high energy phosphates, particularly PCr, will decrease in concentration. The high energy phosphates can be tracked using phosphorus-31 magnetic resonance spectroscopy ({sup 31}P MRS). In Project 2 the UAB Surgical Robotics project focuses on the use of virtual presence to assist with remote surgery and surgical training. The goal of this proposal was to assemble a pilot system for proof of concept. The pilot project was completed successfully and was judged to demonstrate that the concept of remote surgical assistance as applied to surgery and surgical training was feasible and warranted further development. The main objective of Project 3 is to develop a system to allow for the tele-robotic delivery of instrumentation during a functional neurosurgical procedure (Figure 3). Instrumentation such as micro-electrical recording probes or deep brain stimulation leads. Current methods for the delivery of these instruments involve the integration of linear actuators to stereotactic navigation systems. The control of these delivery

  9. Surgical Robotics Research in Cardiovascular Disease

    International Nuclear Information System (INIS)

    Pohost, Gerald M; Guthrie, Barton L; Steiner, Charles

    2008-01-01

    This grant is to support a research in robotics at three major medical centers: the University of Southern California-USC- (Project 1); the University of Alabama at Birmingham-UAB-(Project 2); and the Cleveland Clinic Foundation-CCF-(Project 3). Project 1 is oriented toward cardiovascular applications, while projects 2 and 3 are oriented toward neurosurgical applications. The main objective of Project 1 is to develop an approach to assist patients in maintaining a constant level of stress while undergoing magnetic resonance imaging or spectroscopy. The specific project is to use handgrip to detect the changes in high energy phosphate metabolism between rest and stress. The high energy phosphates, ATP and phosphocreatine (PCr) are responsible for the energy of the heart muscle (myocardium) responsible for its contractile function. If the blood supply to the myocardium in insufficient to support metabolism and contractility during stress, the high energy phosphates, particularly PCr, will decrease in concentration. The high energy phosphates can be tracked using phosphorus-31 magnetic resonance spectroscopy ( 31 P MRS). In Project 2 the UAB Surgical Robotics project focuses on the use of virtual presence to assist with remote surgery and surgical training. The goal of this proposal was to assemble a pilot system for proof of concept. The pilot project was completed successfully and was judged to demonstrate that the concept of remote surgical assistance as applied to surgery and surgical training was feasible and warranted further development. The main objective of Project 3 is to develop a system to allow for the tele-robotic delivery of instrumentation during a functional neurosurgical procedure (Figure 3). Instrumentation such as micro-electrical recording probes or deep brain stimulation leads. Current methods for the delivery of these instruments involve the integration of linear actuators to stereotactic navigation systems. The control of these delivery devices

  10. Consequências cardiovasculares na SAOS Cardiovascular consequences of obstructive sleep apnea syndrome

    Directory of Open Access Journals (Sweden)

    Geraldo Lorenzi Filho

    2010-06-01

    Full Text Available Uma condição clínica muito comum é SAOS, que está associada a várias doenças cardiovasculares, incluindo hipertensão arterial sistêmica, fibrilação atrial e aterosclerose. A associação entre SAOS e doença cardiovascular não é somente uma consequência da sobreposição de fatores de risco, incluindo obesidade, sedentarismo, ser do sexo masculino e ter idade maior. Existem evidências crescentes de que SAOS contribui de forma independente para o aparecimento e a progressão de várias doenças cardiovasculares. Os mecanismos pelos quais SAOS pode afetar o sistema cardiovascular são múltiplos e incluem a ativação do sistema nervoso simpático, inflamação sistêmica, resistência a insulina e geração de estresse oxidativo. Existem evidências que o tratamento de SAOS com CPAP pode reduzir a pressão arterial, sinais precoces de aterosclerose, risco de recorrência de fibrilação atrial e mortalidade, principalmente por acidente vascular cerebral e infarto agudo do miocárdio, em pacientes com SAOS grave.Obstructive sleep apnea syndrome (OSAS is a common condition associated with various cardiovascular diseases, including systemic arterial hypertension, atrial fibrillation, and atherosclerosis. The association between OSAS and cardiovascular disease has been related to the overlapping of risk factors, including obesity, having a sedentary lifestyle, being male, and being older. However, there is mounting evidence that OSAS can also independently contribute to the development and progression of various cardiovascular diseases. The mechanisms by which OSAS can affect the cardiovascular system are multiple, including the activation of the sympathetic nervous system, systemic inflammation, insulin resistance, and oxidative stress. There is also evidence that the treatment of OSAS with CPAP can reduce arterial blood pressure, early signs of atherosclerosis, the risk of atrial fibrillation recurrence, and mortality (principally

  11. Cocoa, blood pressure, and cardiovascular health.

    Science.gov (United States)

    Ferri, Claudio; Desideri, Giovambattista; Ferri, Livia; Proietti, Ilenia; Di Agostino, Stefania; Martella, Letizia; Mai, Francesca; Di Giosia, Paolo; Grassi, Davide

    2015-11-18

    High blood pressure is an important risk factor for cardiovascular disease and cardiovascular events worldwide. Clinical and epidemiological studies suggest that cocoa-rich products reduce the risk of cardiovascular disease. According to this, cocoa has a high content in polyphenols, especially flavanols. Flavanols have been described to exert favorable effects on endothelium-derived vasodilation via the stimulation of nitric oxide-synthase, the increased availability of l-arginine, and the decreased degradation of NO. Cocoa may also have a beneficial effect by protecting against oxidative stress alterations and via decreased platelet aggregation, decreased lipid oxidation, and insulin resistance. These effects are associated with a decrease of blood pressure and a favorable trend toward a reduction in cardiovascular events and strokes. Previous meta-analyses have shown that cocoa-rich foods may reduce blood pressure. Long-term trials investigating the effect of cocoa products are needed to determine whether or not blood pressure is reduced on a chronic basis by daily ingestion of cocoa. Furthermore, long-term trials investigating the effect of cocoa on clinical outcomes are also needed to assess whether cocoa has an effect on cardiovascular events. A 3 mmHg systolic blood pressure reduction has been estimated to decrease the risk of cardiovascular and all-cause mortality. This paper summarizes new findings concerning cocoa effects on blood pressure and cardiovascular health, focusing on putative mechanisms of action and "nutraceutical " viewpoints.

  12. Protective effect of thymoquinone improves cardiovascular function, and attenuates oxidative stress, inflammation and apoptosis by mediating the PI3K/Akt pathway in diabetic rats.

    Science.gov (United States)

    Liu, Hui; Liu, Hong-Yang; Jiang, Yi-Nong; Li, Nan

    2016-03-01

    Thymoquinone is the main active monomer extracted from black cumin and has anti‑inflammatory, antioxidant and anti‑apoptotic functions. However, the protective effects of thymoquinone on cardiovascular function in diabetes remain to be fully elucidated. The present study aimed to investigate the molecular mechanisms underling the beneficial effects of thymoquinone on the cardiovascular function in streptozotocin‑induced diabetes mellitus (DM) rats. Supplement thymoquinone may recover the insulin levels and body weight, inhibit blood glucose levels and reduce the heart rate in DM‑induced rats. The results indicated that the heart, liver and lung to body weight ratios, in addition to the blood pressure levels, were similar for each experimental group. Treatment with thymoquinone significantly reduced oxidative stress damage, inhibited the increased endothelial nitric oxide synthase protein expression and suppressed the elevation of cyclooxygenase‑2 levels in DM‑induced rats. In addition, thymoquinone significantly suppressed the promotion of tumor necrosis factor‑α and interleukin‑6 levels in the DM‑induced rats. Furthermore, administration of thymoquinone significantly reduced caspase‑3 activity and the promotion of phosphorylated‑protein kinase B (Akt) protein expression levels in DM‑induced rats. These results suggest that the protective effect of thymoquinone improves cardiovascular function and attenuates oxidative stress, inflammation and apoptosis by mediating the phosphatidylinositol 3‑kinase/Akt pathway in DM‑induced rats.

  13. The reaction of the cardio-vascular and sympathico-adrenal systems to intellectual activity with emotional stress. [human operator performance

    Science.gov (United States)

    Tomashevskaya, L. I.

    1975-01-01

    The effect of emotiogenic factors on an operator's intellectual activity were studied for differing working regimes on an experimental control panel that provided for light, sonic, and electrocutaneous stimuli. The latter stimulus was activated automatically if the subject gave an incorrect response. It was shown that the working capacity of the operator under stress depends to a great extent on the effect of the emotiogenic factors on the individual functioning characteristics of the cardiovascular and sympathetic-adrenal systems. Moral, intellectual, willpower, emotional, and other personality traits are decisive factors of operator function.

  14. Cardiovascular magnetic resonance in hypertrophic cardiomyopathy and infiltrative cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Rebecca Schofield

    2016-11-01

    Full Text Available Hypertrophic cardiomyopathy (HCM is the most common inherited cardiac disease. Cardiac imaging plays a key role in the diagnosis and management, with cardiovascular magnetic resonance (CMR an important modality. CMR provides a number of different techniques in one examination: structure and function, flow imaging and tissue characterisation particularly with the late gadolinium enhancement (LGE technique. Other techniques include vasodilator perfusion, mapping (especially T1 mapping and extracellular volume quantification [ECV] and diffusion-weighted imaging with its potential to detect disarray. Clinically, the uses of CMR are diverse. The imaging must be considered within the context of work-up, particularly the personal and family history, Electrocardiogram (ECG and echocardiogram findings. Subtle markers of possible HCM can be identified in genotype positive left ventricular hypertrophy (LVH-negative subjects. CMR has particular advantages for assessment of the left ventricle (LV apex and is able to detect both missed LVH (apical and basal antero-septum, when the echocardiography is normal but the ECG abnormal. CMR is important in distinguishing HCM from both common phenocopies (hypertensive heart disease, athletic adaptation, ageing related changes and rarer pheno and/or genocopies such as Fabry disease and amyloidosis. For these, in particular the LGE technique and T1 mapping are very useful with a low T1 in Fabry’s, and high T1 and very high ECV in amyloidosis. Moreover, the tissue characterisation that is possible using CMR offers a potential role in patient risk stratification, as scar is a very strong predictor of future heart failure. Scar may also play a role in the prediction of sudden death. CMR is helpful in follow-up assessment, especially after septal alcohol ablation and myomectomy.

  15. Tracking the harmonic response of magnetically-soft sensors for wireless temperature, stress, and corrosive monitoring

    Science.gov (United States)

    Ong, Keat G.; Grimes, Craig A.

    2002-01-01

    This paper describes the application of magnetically-soft ribbon-like sensors for measurement of temperature and stress, as well as corrosive monitoring, based upon changes in the amplitudes of the higher-order harmonics generated by the sensors in response to a magnetic interrogation signal. The sensors operate independently of mass loading, and so can be placed or rigidly embedded inside nonmetallic, opaque structures such as concrete or plastic. The passive harmonic-based sensor is remotely monitored through a single coplanar interrogation and detection coil. Effects due to the relative location of the sensor are eliminated by tracking harmonic amplitude ratios, thereby, enabling wide area monitoring. The wireless, passive, mass loading independent nature of the described sensor platform makes it ideally suited for long-term structural monitoring applications, such as measurement of temperature and stress inside concrete structures. A theoretical model is presented to explain the origin and behavior of the higher-order harmonics in response to temperature and stress. c2002 Elsevier Science B.V. All rights reserved.

  16. Periodontal Disease-Induced Atherosclerosis and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Tomoko Kurita-Ochiai

    2015-09-01

    Full Text Available Periodontal disease is a highly prevalent disorder affecting up to 80% of the global population. Recent epidemiological studies have shown an association between periodontal disease and cardiovascular disease, as oxidative stress plays an important role in chronic inflammatory diseases such as periodontal disease and cardiovascular disease. In this review, we focus on the mechanisms by which periodontopathic bacteria cause chronic inflammation through the enhancement of oxidative stress and accelerate cardiovascular disease. Furthermore, we comment on the antioxidative activity of catechin in atherosclerosis accelerated by periodontitis.

  17. The Impact of Early Life Stress on Growth and Cardiovascular Risk: A Possible Example for Autonomic Imprinting?

    Science.gov (United States)

    Buchhorn, Reiner; Meint, Sebastian; Willaschek, Christian

    2016-01-01

    Early life stress is imprinting regulatory properties with life-long consequences. We investigated heart rate variability in a group of small children with height below the third percentile, who experienced an episode of early life stress due to heart failure or intra uterine growth retardation. These children appear to develop autonomic dysfunction in later life. Compared to the healthy control group heart rate variability (HRV) is reduced on average in a group of 101 children with short stature. Low HRV correlates to groups of children born small for gestational age (SGA), children with cardiac growth failure and children with congenital syndromes, but not to those with constitutional growth delay (CGD), who had normal HRV. Reduced HRV indicated by lower RMSSD and High Frequency (HF)-Power is indicating reduced vagal activity as a sign of autonomic imbalance. It is not short stature itself, but rather the underlying diseases that are the cause for reduced HRV in children with height below the third percentile. These high risk children-allocated in the groups with an adverse autonomic imprinting in utero or infancy (SGA, congenital heart disease and congenital syndromes)-have the highest risk for 'stress diseases' such as cardiovascular disease in later life. The incidence of attention deficit disorder is remarkably high in our group of short children.

  18. Stress induced modulation of magnetic domain diffraction of single crystalline yttrium iron garnet

    Science.gov (United States)

    Mito, Shinichiro; Yoshihara, Yuki; Takagi, Hiroyuki; Inoue, Mitsuteru

    2018-05-01

    Stress induced modulation of the diffraction angle and efficiency of the light reflected from a stripe-domain magnetic garnet was demonstrated. The spacing of the magnetic domain was changed using the inverse magnetostriction effect. The sample structure was a piezo actuator/Al reflection layer/magnetic garnet substrate. A diffraction angle between the 0th and 1st ordered light was changed from 9.12 deg. to 10.20 deg. This result indicates that the domain spacing was changed from 3.3 μm to 3.0 μm. The change of the diffraction angle was irreversible for the voltage. However, reversible, linear and continuous change of the diffraction efficiency was observed. These results could be applicable for a voltage-driven optical solid state light deflector with low power consumption and high switching speed.

  19. Effects of Music Therapy on the Cardiovascular and Autonomic Nervous System in Stress-Induced University Students: A Randomized Controlled Trial.

    Science.gov (United States)

    Lee, Kyoung Soon; Jeong, Hyeon Cheol; Yim, Jong Eun; Jeon, Mi Yang

    2016-01-01

    Stress is caused when a particular relationship between the individual and the environment emerges. Specifically, stress occurs when an individual's abilities are challenged or when one's well-being is threatened by excessive environmental demands. The aim of this study was to measure the effects of music therapy on stress in university students. Randomized controlled trial. Sixty-four students were randomly assigned to the experimental group (n = 33) or the control group (n = 31). Music therapy. Initial measurement included cardiovascular indicators (blood pressure and pulse), autonomic nervous activity (standard deviation of the normal-to-normal intervals [SDNN], normalized low frequency, normalized high frequency, low/high frequency), and subjective stress. After the first measurement, participants in both groups were exposed to a series of stressful tasks, and then a second measurement was conducted. The experimental group then listened to music for 20 minutes and the control group rested for 20 minutes. A third and final measurement was then taken. There were no significant differences between the two groups in the first or second measurement. However, after music therapy, the experimental group and the control group showed significant differences in all variables, including systolic blood pressure (p = .026), diastolic blood pressure (p = .037), pulse (p music tends to relax the body and may stimulate the parasympathetic nervous system. These results suggest music therapy as an intervention for stress reduction.

  20. Personality and physiological reactions to acute psychological stress.

    Science.gov (United States)

    Bibbey, Adam; Carroll, Douglas; Roseboom, Tessa J; Phillips, Anna C; de Rooij, Susanne R

    2013-10-01

    Stable personality traits have long been presumed to have biological substrates, although the evidence relating personality to biological stress reactivity is inconclusive. The present study examined, in a large middle aged cohort (N=352), the relationship between key personality traits and both cortisol and cardiovascular reactions to acute psychological stress. Salivary cortisol and cardiovascular activity were measured at rest and in response to a psychological stress protocol comprising 5min each of a Stroop task, mirror tracing, and a speech task. Participants subsequently completed the Big Five Inventory to assess neuroticism, agreeableness, openness to experience, extraversion, and conscientiousness. Those with higher neuroticism scores exhibited smaller cortisol and cardiovascular stress reactions, whereas participants who were less agreeable and less open had smaller cortisol and cardiac reactions to stress. These associations remained statistically significant following adjustment for a range of potential confounding variables. Thus, a negative personality disposition would appear to be linked to diminished stress reactivity. These findings further support a growing body of evidence which suggests that blunted stress reactivity may be maladaptive. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Cardiovascular reactivity in hypertensives: differential effect of expressing and inhibiting emotions during moments of interpersonal stress.

    Science.gov (United States)

    Lipp, Marilda E Novaes; Pereira, Márcia M Bignotto; Justo, Ana Paula; de Matos, Thania M Gomes

    2006-11-01

    This study investigated cardiovascular reactivity of hypertensive adults during periods of emotional stress. Two types of instructions were given at different moments, to the same subject, either to express or to suppress feelings during role-play. Expressing, but not inhibiting, emotions elicited significantly higher reactivity during responding to negative scenes, followed by responding during the positive interactions. Blood pressure increases in both expressing and inhibiting conditions, were also found during the instruction periods. Results indicated that socially demanding situations represent a stressor whose effects may vary depending on whether or not respondents regulate expression of emotions. It is suggested that the difficulty in expressing emotions found in some hypertensive individuals may have the function of controlling or reducing blood pressure reactivity.

  2. Magnetic resonance pharmacological stress for detecting coronary disease. Comparison with echocardiography

    International Nuclear Information System (INIS)

    Baer, F.M.; Crnac, J.; Jochims, M.; Schneider, C.; Erdmann, E.; Schmidt, M.; Theissen, P.; Schicha, H.

    2000-01-01

    Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Although exercise ECG remains the primary approach for the detection of ischemia in patients with chest pain syndromes, its sensitivity and specificity is limited and exercise ECG does not provide detailed information about the localisation and extent of CAD. Stress echocardiography has been used for the detection of ischemia for more than a decade and has become an increasingly popular noninvasive method for the detection of CAD. In experienced hands wall motion analysis based on stress echocardiography has proved to be as sensitive and specific for the detection of myocardial ischemia as scintigraphic techniques. Recent technical improvements, namely the availability of ultrafast imaging sequences with a significant reduction of imaging time have initiated several studies which examined the combination of pharmacological stress and magnetic resonance imaging (MRI) for the detection of suspected CAD. The most well developed stress-MRI technique is wall motion imaging during dobutamine stress. This technique is analogous to stress echocardiography, but MRI has the inherent advantages of better resolution, higher reproducibility and true long and short axis imaging with contiguous parallel slices. However, the clinical impact of MRI for the diagnosis of CAD is still low. Further technical developments including real time imaging and a reliable automated quantitative analysis of left ventricular function are required before stress-MRI becomes a serious challenge to stressechocardiography in the clinical arena. Currently, only a few MRI facilities and physicians are dedicated to pharmacological stress testing with MRI and the future clinical impact of this promising technique will depend on its potential to provide information beyond myocardial function including perfusion, metabolism and coronary anatomy in form of a ''one-stop''-shop for the cardiac patient

  3. Detection of hydroxyapatite in calcified cardiovascular tissues.

    Science.gov (United States)

    Lee, Jae Sam; Morrisett, Joel D; Tung, Ching-Hsuan

    2012-10-01

    The objective of this study is to develop a method for selective detection of the calcific (hydroxyapatite) component in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues ex vivo. This method uses a novel optical molecular imaging contrast dye, Cy-HABP-19, to target calcified cells and tissues. A peptide that mimics the binding affinity of osteocalcin was used to label hydroxyapatite in vitro and ex vivo. Morphological changes in vascular smooth muscle cells were evaluated at an early stage of the mineralization process induced by extrinsic stimuli, osteogenic factors and a magnetic suspension cell culture. Hydroxyapatite components were detected in monolayers of these cells in the presence of osteogenic factors and a magnetic suspension environment. Atherosclerotic plaque contains multiple components including lipidic, fibrotic, thrombotic, and calcific materials. Using optical imaging and the Cy-HABP-19 molecular imaging probe, we demonstrated that hydroxyapatite components could be selectively distinguished from various calcium salts in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues, carotid endarterectomy samples and aortic valves, ex vivo. Hydroxyapatite deposits in cardiovascular tissues were selectively detected in the early stage of the calcification process using our Cy-HABP-19 probe. This new probe makes it possible to study the earliest events associated with vascular hydroxyapatite deposition at the cellular and molecular levels. This target-selective molecular imaging probe approach holds high potential for revealing early pathophysiological changes, leading to progression, regression, or stabilization of cardiovascular diseases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Hypothalamic-Pituitary-Adrenal Axis Modulation of Glucocorticoids in the Cardiovascular System.

    Science.gov (United States)

    Burford, Natalie G; Webster, Natalia A; Cruz-Topete, Diana

    2017-10-16

    The collective of endocrine organs acting in homeostatic regulation-known as the hypothalamic-pituitary-adrenal (HPA) axis-comprises an integration of the central nervous system as well as peripheral tissues. These organs respond to imminent or perceived threats that elicit a stress response, primarily culminating in the release of glucocorticoids into the systemic circulation by the adrenal glands. Although the secretion of glucocorticoids serves to protect and maintain homeostasis in the typical operation at baseline levels, inadequate regulation can lead to physiologic and psychologic pathologies. The cardiovascular system is especially susceptible to prolonged dysregulation of the HPA axis and glucocorticoid production. There is debate about whether cardiovascular health risks arise from the direct detrimental effects of stress axis activation or whether pathologies develop secondary to the accompanying metabolic strain of excess glucocorticoids. In this review, we will explore the emerging research that indicates stress does have direct effects on the cardiovascular system via the HPA axis activation, with emphasis on the latest research on the impact of glucocorticoids signaling in the vasculature and the heart.

  5. Hypothalamic-Pituitary-Adrenal Axis Modulation of Glucocorticoids in the Cardiovascular System

    Directory of Open Access Journals (Sweden)

    Natalie G. Burford

    2017-10-01

    Full Text Available The collective of endocrine organs acting in homeostatic regulation—known as the hypothalamic-pituitary-adrenal (HPA axis—comprises an integration of the central nervous system as well as peripheral tissues. These organs respond to imminent or perceived threats that elicit a stress response, primarily culminating in the release of glucocorticoids into the systemic circulation by the adrenal glands. Although the secretion of glucocorticoids serves to protect and maintain homeostasis in the typical operation at baseline levels, inadequate regulation can lead to physiologic and psychologic pathologies. The cardiovascular system is especially susceptible to prolonged dysregulation of the HPA axis and glucocorticoid production. There is debate about whether cardiovascular health risks arise from the direct detrimental effects of stress axis activation or whether pathologies develop secondary to the accompanying metabolic strain of excess glucocorticoids. In this review, we will explore the emerging research that indicates stress does have direct effects on the cardiovascular system via the HPA axis activation, with emphasis on the latest research on the impact of glucocorticoids signaling in the vasculature and the heart.

  6. Assessment of cardiovascular reflexes is of limited value in predicting maximal +Gz-tolerance

    NARCIS (Netherlands)

    van Lieshout, E. J.; van Lieshout, J. J.; Krol, J.; Simons, M.; Karemaker, J. M.

    1992-01-01

    The importance of +Gz-induced loss of consciousness as a major cause of inflight incapacitation emphasizes the need for predicting +Gz-tolerance and investigating its possible determinants. The cardiovascular changes from +Gz-stress are initially counteracted reflexly by the cardiovascular autonomic

  7. Oxidative stress as a mechanism of added sugar-induced cardiovascular disease.

    Science.gov (United States)

    Prasad, Kailash; Dhar, Indu

    2014-12-01

    Added sugars comprising of table sugar, brown sugar, corn syrup, maple syrup, honey, molasses, and other sweeteners in the prepared processed foods and beverages have been implicated in the pathophysiology of cardiovascular diseases. This article deals with the reactive oxygen species (ROS) as a mechanism of sugar-induced cardiovascular diseases. There is an association between the consumption of high levels of serum glucose with cardiovascular diseases. Various sources of sugar-induced generation of ROS, including mitochondria, nicotinamide adenine dinucleotide phosphate-oxidase, advanced glycation end products, insulin, and uric acid have been discussed. The mechanism by which ROS induce the development of atherosclerosis, hypertension, peripheral vascular disease, coronary artery disease, cardiomyopathy, heart failure, and cardiac arrhythmias have been discussed in detail. In conclusion, the data suggest that added sugars induce atherosclerosis, hypertension, peripheral vascular disease, coronary artery disease, cardiomyopathy, heart failure, and cardiac arrhythmias and that these effects of added sugars are mediated through ROS.

  8. The Implicit Positive and Negative Affect Test: Validity and Relationship with Cardiovascular Stress-Responses.

    Science.gov (United States)

    van der Ploeg, Melanie M; Brosschot, Jos F; Thayer, Julian F; Verkuil, Bart

    2016-01-01

    Self-report, i.e., explicit, measures of affect cannot fully explain the cardiovascular (CV) responses to stressors. Measuring affect beyond self-report, i.e., using implicit measures, could add to our understanding of stress-related CV activity. The Implicit Positive and Negative Affect Test (IPANAT) was administered in two studies to test its ecological validity and relation with CV responses and self-report measures of affect. In Study 1 students (N = 34) viewed four film clips inducing anger, happiness, fear, or no emotion, and completed the IPANAT and the Positive And Negative Affect Scale at baseline and after each clip. Implicit negative affect (INA) was higher and implicit positive affect (IPA) was lower after the anger inducing clip and vice versa after the happiness inducing clip. In Study 2 students performed a stressful math task with (n = 14) or without anger harassment (n = 15) and completed the IPANAT and a Visual Analog Scale as an explicit measure afterwards. Systolic (SBP), diastolic (DBP) blood pressure, heart rate (HR), heart rate variability (HRV), and total peripheral resistance (TPR) were recorded throughout. SBP and DBP were higher and TPR was lower in the harassment condition during the task with a prolonged effect on SBP and DBP during recovery. As expected, explicit negative affect (ENA) was higher and explicit positive affect (EPA) lower after harassment, but ENA and EPA were not related to CV activity. Although neither INA nor IPA differed between the tasks, during both tasks higher INA was related to higher SBP, lower HRV and lower TPR and to slower recovery of DBP after both tasks. Low IPA was related to slower recovery of SBP and DBP after the tasks. Implicit affect was not related to recovery of HR, HRV, and TPR. In conclusion, the IPANAT seems to respond to film clip-induced negative and positive affect and was related to CV activity during and after stressful tasks. These findings support the theory that implicitly measured affect

  9. Influence of applied compressive stress on the hysteresis curves and magnetic domain structure of grain-oriented transverse Fe-3%Si steel

    International Nuclear Information System (INIS)

    Perevertov, O; Schäfer, R

    2012-01-01

    The influence of an applied compressive stress on the hysteresis curve and domain structure in conventional (1 1 0) [0 0 1] Fe-3%Si steel cut transverse to the rolling direction is studied. Quasistatic hysteresis loops under compressive stress up to 75 MPa were measured. The magnetic domains and magnetization processes were observed by longitudinal Kerr microscopy at different levels of stress. It is shown that the bulk hysteresis loop can be described with a good accuracy by the action of an effective field, which is the product of the stress and a function of magnetization. Domain observations have shown that the reasons for the effective field are demagnetizing fields due to the disappearance of supplementary domains along [0 1 0] and [1 0 0] at low fields and different domain systems in different grains at moderate fields. The latter are caused by differences in grain sensitivity to stress depending on the degree of misorientation. A decrease in the effective field above 1 T is connected with a transformation of all grains into the same domain system—the column pattern. (paper)

  10. Arrhythmogenic right ventricular cardiomyopathy mimics: role of cardiovascular magnetic resonance

    Science.gov (United States)

    2013-01-01

    Background Cardiovascular magnetic resonance (CMR) is commonly used in patients with suspected arrhythmogenic right ventricular cardiomyopathy (ARVC) based on ECG, echocardiogram and Holter. However, various diseases may present with clinical characteristics resembling ARVC causing diagnostic dilemmas. The aim of this study was to explore the role of CMR in the differential diagnosis of patients with suspected ARVC. Methods 657 CMR referrals suspicious for ARVC in a single tertiary referral centre were analysed. Standardized CMR imaging protocols for ARVC were performed. Potential ARVC mimics were grouped into: 1) displacement of the heart, 2) right ventricular overload, and 3) non ARVC-like cardiac scarring. For each, a judgment of clinical impact was made. Results Twenty patients (3.0%) fulfilled imaging ARVC criteria. Thirty (4.6%) had a potential ARVC mimic, of which 25 (3.8%) were considered clinically important: cardiac displacement (n=17), RV overload (n=7) and non-ARVC like myocardial scarring (n=4). One patient had two mimics; one patient had dual pathology with important mimic and ARVC. RV overload and scarring conditions were always thought clinically important whilst the importance of cardiac displacement depended on the degree of displacement from severe (partial absence of pericardium) to epiphenomenon (minor kyphoscoliosis). Conclusions Some patients referred for CMR with suspected ARVC fulfil ARVC imaging criteria (3%) but more have otherwise unrecognised diseases (4.6%) mimicking potentially ARVC. Clinical assessment should reflect this, emphasising the assessment and/or exclusion of potential mimics in parallel with the detection of ARVC major and minor criteria. PMID:23398958

  11. The influence of applied tensile stress on power loss in Co-rich amorphous Co-Fe-Si-B ribbons with induced magnetic anisotropy

    DEFF Research Database (Denmark)

    Nielsen, H; Nielsen, K; Nielsen, Otto V

    1982-01-01

    and atf = 400Hz,J_{max} = 0.10T. Measurements are carried out on samples in a stress-relieved state and with magnetic anisotropies induced by stress or field annealing. Atf = 50Hz, a minimum m Ptversus σ is observed. The σ-value (sigma_{min}) corresponding to the minimum PTincreases with increasing |Ku......|. Atf = 400Hz, a minimum in PTversus σ is observed in the samples with induced magnetic anisotropy, whereassigma_{min} = 0in the stress-relieved samiales. However, no correlation between andsigma_{min}and Kuis possible from the present data....

  12. Dobutamine cardiovascular magnetic resonance for the detection of myocardial ischemia with the use of myocardial tagging.

    Science.gov (United States)

    Kuijpers, Dirkjan; Ho, Kai Yiu J A M; van Dijkman, Paul R M; Vliegenthart, Rozemarijn; Oudkerk, Matthijs

    2003-04-01

    The purpose of this study was to assess the value of high-dose dobutamine cardiovascular magnetic resonance (CMR) with myocardial tagging for the detection of wall motion abnormalities as a measure of myocardial ischemia in patients with known or suspected coronary artery disease. Two hundred eleven consecutive patients with chest pain underwent dobutamine-CMR 4 days after antianginal medication was stopped. Dobutamine-CMR was performed at rest and during increasing doses of dobutamine. Cine-images were acquired during breath-hold with and without myocardial tagging at 3 short-axis levels. Regional wall motion was assessed in a 16-segment short-axis model. Patients with new wall motion abnormalities (NWMA) were examined by coronary angiography. Dobutamine-CMR was successfully performed in 194 patients. Dobutamine-CMR without tagging detected NWMA in 58 patients, whereas NWMA were detected in 68 patients with tagging (P=0.002, McNemar). Coronary angiography showed coronary artery disease in 65 (96%) of these 68 patients. All but 3 of the 65 patients needed revascularization. In the 112 patients with a negative dobutamine-CMR study, without baseline wall motion abnormalities, the cardiovascular occurrence-free survival rate was 98.2% during the mean follow-up period of 17.3 months (range, 7 to 31). Dobutamine-CMR with myocardial tagging detected more NWMA compared with dobutamine-CMR without tagging and reliably separated patients with a normal life expectancy from those at increased risk of major adverse cardiac events.

  13. Magnetically-tunable rebound property for variable elastic devices made of magnetic elastomer and polyurethane foam

    Science.gov (United States)

    Oguro, Tsubasa; Endo, Hiroyuki; Kawai, Mika; Mitsumata, Tetsu

    2017-12-01

    A device consisting of a phase of magnetic elastomer, a phase of polyurethane foam (PUF), and permanent magnet was fabricated and the stress-strain curves for the two-phase magnetic elastomer were measured by a uniaxial compression measurement. A disk of magnetic elastomer was adhered on a disk of PUF by an adhesive agent. The PUF thickness was varied from 1 mm to 5 mm while the thickness of magnetic elastomers was constant at 5 mm. The stress at a strain of 0.15 for the two-phase magnetic elastomers was evaluated in the absence and in the presence of a magnetic field of 410 mT. The stress at 0 mT decreased remarkably with the PUF thickness due to the deformation of the PUF phase. On the other hand, the stress at 410 mT slightly decreased with the thickness; however, it kept high values even at high thickness. When the PUF thickness was 5 mm, the maximum stress increment with 45 times to the off-field stress was observed. An experiment using ping-pong balls demonstrated that the coefficient of restitution for the two-phase magnetic elastomers can be dramatically altered by the magnetic field.

  14. Efficient multiscale magnetic-domain analysis of iron-core material under mechanical stress

    Science.gov (United States)

    Nishikubo, Atsushi; Ito, Shumpei; Mifune, Takeshi; Matsuo, Tetsuji; Kaido, Chikara; Takahashi, Yasuhito; Fujiwara, Koji

    2018-05-01

    For an efficient analysis of magnetization, a partial-implicit solution method is improved using an assembled domain structure model with six-domain mesoscopic particles exhibiting pinning-type hysteresis. The quantitative analysis of non-oriented silicon steel succeeds in predicting the stress dependence of hysteresis loss with computation times greatly reduced by using the improved partial-implicit method. The effect of cell division along the thickness direction is also evaluated.

  15. Impact of early, late, and no ST-segment resolution measured by continuous ST Holter monitoring on left ventricular ejection fraction and infarct size as determined by cardiovascular magnetic resonance imaging

    NARCIS (Netherlands)

    Haeck, Joost D. E.; Verouden, Niels J. W.; Kuijt, Wichert J.; Koch, Karel T.; Majidi, Mohamed; Hirsch, Alexander; Tijssen, Jan G. P.; Krucoff, Mitchell W.; de Winter, Robbert J.

    2011-01-01

    Background: The goal of this study is to determine the predictive value of ST-segment resolution (STR) early after percutaneous coronary intervention (PCI), late STR, and no STR for left ventricular ejection fraction (LVEF) and infarct size (IS) by cardiovascular magnetic resonance (CMR) at

  16. Task stressfulness moderates the effects of verbal person centeredness on cardiovascular reactivity: a dual-process account of the reactivity hypothesis.

    Science.gov (United States)

    Bodie, Graham D

    2012-01-01

    This study sought to investigate the impact of person-centered comfort on cardiovascular reactivity and to test a recently developed dual-process theory of supportive message outcomes proposing that the impact of supportive communication is moderated by the motivation and ability to attend to message content. Participants (n = 179) completed a public speaking task that served to experimentally manipulate stress. During the preparation period, instant messages containing either low or high person-centered messages or containing no imbedded supportive message were sent. Results indicated that, in line with theoretical predictions, message content did influence mean arterial pressure and heart rate for participants exposed to moderate but not to low or high stress. Results are discussed in terms of the dual-process theory of supportive message outcomes, and the discussion offers both theoretical and practical implications of the research.

  17. The Finnish Cardiovascular Study (FINCAVAS): characterising patients with high risk of cardiovascular morbidity and mortality

    International Nuclear Information System (INIS)

    Nieminen, Tuomo; Turjanmaa, Väinö; Kähönen, Mika; Lehtinen, Rami; Viik, Jari; Lehtimäki, Terho; Niemelä, Kari; Nikus, Kjell; Niemi, Mari; Kallio, Janne; Kööbi, Tiit

    2006-01-01

    The purpose of the Finnish Cardiovascular Study (FINCAVAS) is to construct a risk profile – using genetic, haemodynamic and electrocardiographic (ECG) markers – of individuals at high risk of cardiovascular diseases, events and deaths. All patients scheduled for an exercise stress test at Tampere University Hospital and willing to participate have been and will be recruited between October 2001 and December 2007. The final number of participants is estimated to reach 5,000. Technically successful data on exercise tests using a bicycle ergometer have been collected of 2,212 patients (1,400 men and 812 women) by the end of 2004. In addition to repeated measurement of heart rate and blood pressure, digital high-resolution ECG at 500 Hz is recorded continuously during the entire exercise test, including the resting and recovery phases. About 20% of the patients are examined with coronary angiography. Genetic variations known or suspected to alter cardiovascular function or pathophysiology are analysed to elucidate the effects and interactions of these candidate genes, exercise and commonly used cardiovascular medications. FINCAVAS compiles an extensive set of data on patient history, genetic variation, cardiovascular parameters, ECG markers as well as follow-up data on clinical events, hospitalisations and deaths. The data enables the development of new diagnostic and prognostic tools as well as assessments of the importance of existing markers

  18. Cardiac remodeling following percutaneous mitral valve repair - initial results assessed by cardiovascular magnetic resonance imaging

    DEFF Research Database (Denmark)

    Radunski, U K; Franzen, O; Barmeyer, A

    2014-01-01

    PURPOSE: Percutaneous mitral valve repair with the MitraClip device (Abbott Vascular, Redwood City, California, USA) is a novel therapeutic option in patients with mitral regurgitation. This study evaluated the feasibility of cardiac volume measurements by cardiovascular magnetic resonance imaging...... (CMR) to assess reverse myocardial remodeling in patients after MitraClip implantation. MATERIALS AND METHODS: 12 patients underwent CMR at baseline (BL) before and at 6 months follow-up (FU) after MitraClip implantation. Cine-CMR was performed in short- and long-axes for the assessment of left...... end-systolic (48 [42 - 80] vs. 51 [40 - 81] ml/m(2); p = 0.48), and LA (87 [55 - 124] vs. 92 [48 - 137] ml/m(2); p = 0.20) volume indices between BL and FU. CONCLUSION: CMR enables the assessment of cardiac volumes in patients after MitraClip implantation. Our CMR findings indicate that percutaneous...

  19. Effect of sex on the cardiovascular response to adrenaline in humans.

    NARCIS (Netherlands)

    Schouwenberg, B.J.J.W.; Rietjens, S.J.; Smits, P.; Galan, B.E. de

    2006-01-01

    Cardiovascular responsiveness to stress conditions differs between men and women. It is not known to what extent this observation is explained by differences in the release of stress hormones like adrenaline, or by differences in the response to adrenaline. Therefore, we quantified the hemodynamic

  20. Plasma Total Cysteine and Cardiovascular Risk Burden: Action and Interaction

    OpenAIRE

    De Chiara, Benedetta; Sedda, Valentina; Parolini, Marina; Campolo, Jonica; De Maria, Renata; Caruso, Raffaele; Pizzi, Gianluigi; Disoteo, Olga; Dellanoce, Cinzia; Corno, Anna Rosa; Cighetti, Giuliana; Parodi, Oberdan

    2012-01-01

    We hypothesized that redox analysis could provide sensitive markers of the oxidative pathway associated to the presence of an increasing number of cardiovascular risk factors (RFs), independently of type. We classified 304 subjects without cardiovascular disease into 4 groups according to the total number of RFs (smoking, hypertension, hypercholesterolaemia, hyperhomocysteinaemia, diabetes, obesity, and their combination). Oxidative stress was evaluated by measuring plasma total and reduced h...

  1. Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

    Science.gov (United States)

    Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

    2007-12-01

    Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

  2. 4D cardiovascular magnetic resonance velocity mapping of alterations of right heart flow patterns and main pulmonary artery hemodynamics in tetralogy of Fallot

    Science.gov (United States)

    2012-01-01

    Background To assess changes in right heart flow and pulmonary artery hemodynamics in patients with repaired Tetralogy of Fallot (rTOF) we used whole heart, four dimensional (4D) velocity mapping (VM) cardiovascular magnetic resonance (CMR). Methods CMR studies were performed in 11 subjects with rTOF (5M/6F; 20.1 ± 12.4 years) and 10 normal volunteers (6M/4F; 34.2 ± 13.4 years) on clinical 1.5T and 3.0T MR scanners. 4D VM-CMR was performed using PC VIPR (Phase Contrast Vastly undersampled Isotropic Projection Reconstruction). Interactive streamline and particle trace visualizations of the superior and inferior vena cava (IVC and SVC, respectively), right atrium (RA), right ventricle (RV), and pulmonary artery (PA) were generated and reviewed by three experienced readers. Main PA net flow, retrograde flow, peak flow, time-to-peak flow, peak acceleration, resistance index and mean wall shear stress were quantified. Differences in flow patterns between the two groups were tested using Fisher's exact test. Differences in quantitative parameters were analyzed with the Kruskal-Wallis rank sum test. Results 4D VM-CMR was successfully performed in all volunteers and subjects with TOF. Right heart flow patterns in rTOF subjects were characterized by (a) greater SVC/IVC flow during diastole than systole, (b) increased vortical flow patterns in the RA and in the RV during diastole, and (c) increased helical or vortical flow features in the PA's. Differences in main PA retrograde flow, resistance index, peak flow, time-to-peak flow, peak acceleration and mean wall shear stress were statistically significant. Conclusions Whole heart 4D VM-CMR with PC VIPR enables detection of both normal and abnormal right heart flow patterns, which may allow for comprehensive studies to evaluate interdependencies of post-surgically altered geometries and hemodynamics. PMID:22313680

  3. Character strengths, social anxiety, and physiological stress reactivity

    Directory of Open Access Journals (Sweden)

    Tingting Li

    2017-05-01

    Full Text Available In this paper, the effects of character strengths on the physiological reactivity to social anxiety induced by the Trier Social Stress Task were reported. On the basis of their scores in the Chinese Virtues Questionnaire, 30 college students were assigned to either high- (n = 15 or low-character-strength (n = 15 groups. Their psychological stress and physiological data across three laboratory stages (namely, baseline, stress exposure, and post-stress were collected. Results indicated that individuals with high character strengths exhibited rapid cardiovascular recovery from baseline to post-stress even if high- and low-character-strength groups showed similar patterns of cardiovascular arousal in response to the stress at baseline and stress exposure. These results prove that character strengths are stress-defense factors that allow for psychological and physiological adaptation to stress.

  4. Nickel--chromium strain gages for cryogenic stress analysis of superconducting structures in high magnetic fields

    International Nuclear Information System (INIS)

    Freynik, H.S. Jr.; Roach, D.R.; Deis, D.W.; Hirzel, D.G.

    1977-01-01

    Evaluation and calibration measurements were performed on commercial nickel-chromium metal-foil strain gages in a high-magnetic-field (12 T), liquid-helium (4.2 K) environment. The purpose was to fully characterize strain gages for use at cryogenic temperatures in high magnetic fields. In this study, the magnetoresistance of a number of strain gages was measured in three orthogonal directions at mechanical strain levels to 8900 μm/m. As a result, a unique calibration curve was defined for magnetoresistance strain errors that is independent of strain level and field direction to 12 T at 4.2 K. A current strain-gage application is the measurement of superconductor mechanical properties. These gages will soon be used in the stress analysis of superconducting fusion magnets during cooldown from ambient temperatures and during operation at 4.2 K with magnetic fields to 12 T

  5. Voltage from mechanical stress in type-II superconductors: Depinning of the magnetic flux by moving dislocations

    OpenAIRE

    Albert, Jaroslav; Chudnovsky, Eugene M.

    2008-01-01

    Mechanical stress causes motion of defects in solids. We show that in a type-II superconductor a moving dislocation generates a pattern of current that exerts the depinning force on the surrounding vortex lattice. Concentration of dislocations and the mechanical stress needed to produce critical depinning currents are shown to be within practical range. When external magnetic field and transport current are present this effect generates voltage across the superconductor. Thus a superconductor...

  6. Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

    Science.gov (United States)

    Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

    2017-06-18

    To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

  7. Trauma- and Stress-Induced Response in Veterans with Alcohol Dependence and Comorbid Post-Traumatic Stress Disorder.

    Science.gov (United States)

    Ralevski, Elizabeth; Southwick, Steven; Jackson, Eric; Jane, Jane Serrita; Russo, Melanie; Petrakis, Ismene

    2016-08-01

    Alcohol dependence (AD) and post-traumatic stress disorder (PTSD) commonly co-occur, and the co-occurrence is associated with worse prognosis than either disorder absent the other. Craving is an important construct related to relapse, but the relationship between PTSD symptoms, craving, and relapse is not well understood. Several studies have documented the relationship between stress and craving in individuals without comorbid PTSD, but the effect on those with comorbid PTSD is not well known. A small literature suggests that trauma imagery affects craving. This is the first study to explore the effects of trauma-induced and stress-induced scripts on alcohol craving, affect, cardiovascular, and cortisol responses in the laboratory. Veterans (n = 25) diagnosed with AD and PTSD who were participating in a randomized clinical treatment trial took part in this laboratory study. Baseline assessment included PTSD symptoms and drinking quantity and frequency over 3 months before study initiation. In the laboratory, participants were exposed to neutral, stressful, and trauma scripts randomly assigned. Main outcomes included craving, anxiety, mood states, salivary cortisol, and cardiovascular responses. Both stress and trauma scripts produced greater increases in craving, negative affect, and cardiovascular reactivity, compared to neutral scripts. Trauma scripts produced significantly stronger craving for alcohol and greater cardiovascular reactivity than stress scripts. Also, trauma-induced but not stress-induced craving was positively correlated with baseline levels of drinking. There were no changes in cortisol levels from pre- to postexposure of any scripts. The results highlight that trauma cues are more salient in inducing alcohol craving than stress cues and higher reactivity is related to more baseline drinking. This finding is consistent with clinical observations that show an association between PTSD symptoms and alcohol relapse. It also underscores the

  8. Prognostic Value of Stress Echocardiography in Patients With Low-Intermediate or High Short-Term (10 Years) Versus Low (Risk of Cardiovascular Disease According to the American College of Cardiology/American Heart Association 2013 Cardiovascular Risk Calculator.

    Science.gov (United States)

    Yao, Siu-Sun; Supariwala, Azhar; Yao, Amanda; Dukkipati, Sai Sreenija; Wyne, Jamshad; Chaudhry, Farooq A

    2015-09-01

    This study evaluates the prognostic value of stress echocardiography (Secho) in short-term (10 years) and lifetime atherosclerotic cardiovascular disease risk-defined groups according to the American College of Cardiology/American Heart Association 2013 cardiovascular risk calculator. The ideal risk assessment and management of patients with low-to-intermediate or high short-term versus low (risk is unclear. The purpose of this study was to evaluate the prognostic value of Secho in short-term and lifetime CV risk-defined groups. We evaluated 4,566 patients (60 ± 13 years; 46% men) who underwent Secho (41% treadmill and 59% dobutamine) with low-intermediate short-term (risk divided into low (risk and third group with high short-term risk (≥20%, n = 3,537). Follow-up (3.2 ± 1.5 years) for nonfatal myocardial infarction (n = 102) and cardiac death (n = 140) were obtained. By univariate analysis, age (p risk and also in those with high short-term CV risk group (3.5% vs 1.0% per year, p risk assessment in patients with low-intermediate or high short-term versus low or high lifetime cardiovascular risk. Event rate with normal Secho is low (≤1% per year) but higher in patients with high short-term CV risk by the American College of Cardiology/American Heart Association 2013 cardiovascular risk calculator. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Cardiac Involvement in Myotonic Dystrophy Type 2 Patients With Preserved Ejection Fraction: Detection by Cardiovascular Magnetic Resonance.

    Science.gov (United States)

    Schmacht, Luisa; Traber, Julius; Grieben, Ulrike; Utz, Wolfgang; Dieringer, Matthias A; Kellman, Peter; Blaszczyk, Edyta; von Knobelsdorff-Brenkenhoff, Florian; Spuler, Simone; Schulz-Menger, Jeanette

    2016-07-01

    Myotonic dystrophy type 2 (DM2) is a genetic disorder characterized by skeletal muscle symptoms, metabolic changes, and cardiac involvement. Histopathologic alterations of the skeletal muscle include fibrosis and fatty infiltration. The aim of this study was to investigate whether subclinical cardiac involvement in DM2 is already detectable in preserved left ventricular function by cardiovascular magnetic resonance. Twenty-seven patients (mean age, 54±10 years; 20 females) with a genetically confirmed diagnosis of DM2 were compared with 17 healthy age- and sex-matched controls using a 1.5 T magnetic resonance imaging. For myocardial tissue differentiation, T1 and T2 mapping, fat/water-separated imaging, focal fibrosis imaging (late gadolinium enhancement [LGE]), and (1)H magnetic resonance spectroscopy were performed. Extracellular volume fraction was calculated. Conduction abnormalities were diagnosed based on Groh criteria. LGE located subepicardial basal inferolateral was detectable in 22% of the patients. Extracellular volume was increased in this region and in the adjacent medial inferolateral segment (P=0.03 compared with healthy controls). In 21% of patients with DM2, fat deposits were detectable (all women). The control group showed no abnormalities. Myocardial triglycerides were not different in LGE-positive and LGE-negative subjects (P=0.47). Six patients had indicators for conduction disease (60% of LGE-positive patients and 12.5% of LGE-negative patients). In DM2, subclinical myocardial injury was already detectable in preserved left ventricular ejection fraction. Extracellular volume was also increased in regions with no focal fibrosis. Myocardial fibrosis was related to conduction abnormalities. © 2016 American Heart Association, Inc.

  10. Ideal cardiovascular health and psychosocial risk factors among Finnish female municipal workers.

    Science.gov (United States)

    Veromaa, Veera; Kautiainen, Hannu; Saxen, Ulla; Malmberg-Ceder, Kirsi; Bergman, Elina; Korhonen, Päivi E

    2017-02-01

    Ideal cardiovascular health has been defined by the American Heart Association as the absence of disease and the presence of seven key health factors and behaviours. However, little is known about the mental aspects associated with ideal cardiovascular health metrics. The objective of this study was to assess the relationships between psychosocial risk factors and ideal cardiovascular health metrics among Finnish women at municipal work units. A cross-sectional study was conducted in Finland among 732 female employees (mean±SD age 48±10 years) from ten work units in 2014. Ideal cardiovascular health metrics were evaluated with a physical examination, laboratory tests, medical history and self-administrated questionnaires. Psychosocial risk factors (social isolation, stress, depressive symptoms, anxiety, hostility and type D personality) were assessed with core questions as suggested by the European Society of Cardiology. The prevalence of having 5-7 ideal cardiovascular health metrics was 183 (25.0%), of whom 54.1% had at least one psychosocial risk factor. Anxiety (31.3%), work stress (30.7%) and type D personality (26.1%) were the most prevalent of the psychosocial risk factors. The prevalence of depressive symptoms ( ppsychosocial risk factors at municipal work units. Although the association is possibly bidirectional, screening and treating depression and dealing with type D personality might be crucial in improving cardiovascular health among women.

  11. Fetal Programming and Cardiovascular Pathology

    Science.gov (United States)

    Alexander, Barbara T.; Dasinger, John Henry; Intapad, Suttira

    2016-01-01

    Low birth weight serves as a crude proxy for impaired growth during fetal life and indicates a failure for the fetus to achieve its full growth potential. Low birth weight can occur in response to numerous etiologies that include complications during pregnancy, poor prenatal care, parental smoking, maternal alcohol consumption or stress. Numerous epidemiological and experimental studies demonstrate that birth weight is inversely associated with blood pressure and coronary heart disease. Sex and age impact the developmental programming of hypertension. In addition, impaired growth during fetal life also programs enhanced vulnerability to a secondary insult. Macrosomia, which occurs in response to maternal obesity, diabetes and excessive weight gain during gestation, is also associated with increased cardiovascular risk. Yet, the exact mechanisms that permanently change the structure, physiology and endocrine health of an individual across their lifespan following altered growth during fetal life are not entirely clear. Transmission of increased risk from one generation to the next in the absence of an additional prenatal insult indicates an important role for epigenetic processes. Experimental studies also indicate that the sympathetic nervous system, the renin angiotensin system, increased production of oxidative stress and increased endothelin play an important role in the developmental programming of blood pressure in later life. Thus, this review will highlight how adverse influences during fetal life and early development program an increased risk for cardiovascular disease including high blood pressure and provide an overview of the underlying mechanisms that contribute to the fetal origins of cardiovascular pathology. PMID:25880521

  12. Fetal programming and cardiovascular pathology.

    Science.gov (United States)

    Alexander, Barbara T; Dasinger, John Henry; Intapad, Suttira

    2015-04-01

    Low birth weight serves as a crude proxy for impaired growth during fetal life and indicates a failure for the fetus to achieve its full growth potential. Low birth weight can occur in response to numerous etiologies that include complications during pregnancy, poor prenatal care, parental smoking, maternal alcohol consumption, or stress. Numerous epidemiological and experimental studies demonstrate that birth weight is inversely associated with blood pressure and coronary heart disease. Sex and age impact the developmental programming of hypertension. In addition, impaired growth during fetal life also programs enhanced vulnerability to a secondary insult. Macrosomia, which occurs in response to maternal obesity, diabetes, and excessive weight gain during gestation, is also associated with increased cardiovascular risk. Yet, the exact mechanisms that permanently change the structure, physiology, and endocrine health of an individual across their lifespan following altered growth during fetal life are not entirely clear. Transmission of increased risk from one generation to the next in the absence of an additional prenatal insult indicates an important role for epigenetic processes. Experimental studies also indicate that the sympathetic nervous system, the renin angiotensin system, increased production of oxidative stress, and increased endothelin play an important role in the developmental programming of blood pressure in later life. Thus, this review will highlight how adverse influences during fetal life and early development program an increased risk for cardiovascular disease including high blood pressure and provide an overview of the underlying mechanisms that contribute to the fetal origins of cardiovascular pathology. © 2015 American Physiological Society.

  13. The cardiovascular system after exercise

    Science.gov (United States)

    Romero, Steven A.; Minson, Christopher T.

    2017-01-01

    Recovery from exercise refers to the time period between the end of a bout of exercise and the subsequent return to a resting or recovered state. It also refers to specific physiological processes or states occurring after exercise that are distinct from the physiology of either the exercising or the resting states. In this context, recovery of the cardiovascular system after exercise occurs across a period of minutes to hours, during which many characteristics of the system, even how it is controlled, change over time. Some of these changes may be necessary for long-term adaptation to exercise training, yet some can lead to cardiovascular instability during recovery. Furthermore, some of these changes may provide insight into when the cardiovascular system has recovered from prior training and is physiologically ready for additional training stress. This review focuses on the most consistently observed hemodynamic adjustments and the underlying causes that drive cardiovascular recovery and will highlight how they differ following resistance and aerobic exercise. Primary emphasis will be placed on the hypotensive effect of aerobic and resistance exercise and associated mechanisms that have clinical relevance, but if left unchecked, can progress to symptomatic hypotension and syncope. Finally, we focus on the practical application of this information to strategies to maximize the benefits of cardiovascular recovery, or minimize the vulnerabilities of this state. We will explore appropriate field measures, and discuss to what extent these can guide an athlete’s training. PMID:28153943

  14. In-situ studies of stress- and magnetic-field-induced phase transformation in a polymer-bonded Ni-Co-Mn-In composite

    International Nuclear Information System (INIS)

    Liu, D.M.; Nie, Z.H.; Wang, G.; Wang, Y.D.; Brown, D.E.; Pearson, J.; Liaw, P.K.; Ren, Y.

    2010-01-01

    A polymer-bonded Ni 45 Co 5 Mn 36.6 In 13.4 ferromagnetic shape-memory composite was fabricated, having magnetic-field-driven shape recovery properties. The thermo-magnetization curves of the composite suggested that the magnetic-field-induced reverse martensitic transformation occurs in the composite. The effects of temperature, stress, and magnetic-field on the phase transformation properties were systematically investigated using an in-situ high-energy X-ray diffraction technique. A temperature-induced reversible martensitic phase transformation was confirmed within the composite, showing a broad phase transformation interval. Stress-induced highly textured martensite was observed in the composite during uniaxial compressive loading, with a residual strain after unloading. The origin of the textured martensite can be explained by the grain-orientation-dependent Bain distortion energy. A recovery strain of ∼1.76% along the compression direction was evidenced in the pre-strained composite with an applied magnetic-field of 5 T. This recovery was caused by the magnetic-field-induced reverse martensitic phase transformation. The phase transformation properties of the ferromagnetic shape-memory composite, different from its bulk alloys, can be well explained by the Clausius-Clapeyron relation. The large magnetic-field-induced strain, together with good ductility and low cost, make the polymer-bonded Ni-Co-Mn-In composites potential candidates for magnetic-field-driven actuators.

  15. Right Ventricular Volumes and Systolic Function by Cardiac Magnetic Resonance and the Impact of Sex, Age, and Obesity in a Longitudinally Followed Cohort Free of Pulmonary and Cardiovascular Disease: The Framingham Heart Study.

    Science.gov (United States)

    Foppa, Murilo; Arora, Garima; Gona, Philimon; Ashrafi, Arman; Salton, Carol J; Yeon, Susan B; Blease, Susan J; Levy, Daniel; O'Donnell, Christopher J; Manning, Warren J; Chuang, Michael L

    2016-03-01

    Cardiac magnetic resonance is uniquely well suited for noninvasive imaging of the right ventricle. We sought to define normal cardiac magnetic resonance reference values and to identify the main determinants of right ventricular (RV) volumes and systolic function using a modern imaging sequence in a community-dwelling, longitudinally followed cohort free of clinical cardiovascular and pulmonary disease. The Framingham Heart Study Offspring cohort has been followed since 1971. We scanned 1794 Offspring cohort members using steady-state free precession cardiac magnetic resonance and identified a reference group of 1336 adults (64±9 years, 576 men) free of prevalent cardiovascular and pulmonary disease. RV trabeculations and papillary muscles were considered cavity volume. Men had greater RV volumes and cardiac output before and after indexation to body size (all Pheart rate account for most of the variability in RV volumes and function in this community-dwelling population. We report sex-specific normative values for RV measurements among principally middle-aged and older adults. RV ejection fraction is greater in women. RV volumes increase with body size, are greater in men, and are smaller in older people. Body surface area seems to be appropriate for indexation of cardiac magnetic resonance-derived RV volumes. © 2016 American Heart Association, Inc.

  16. Cardiovascular effects of air pollution.

    Science.gov (United States)

    Bourdrel, Thomas; Bind, Marie-Abèle; Béjot, Yannick; Morel, Olivier; Argacha, Jean-François

    2017-11-01

    Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM 10 ), fine particles (PM 2.5 ) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10μg/m 3 increase in long-term exposure to PM 2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution and road traffic was associated with an increased risk of arteriosclerosis, as shown by premature aortic and coronary calcification. Short-term increases in air pollution were associated with an increased risk of myocardial infarction, stroke and acute heart failure. The risk was increased even when pollutant concentrations were below European standards. Reinforcing the evidence from epidemiological studies, numerous experimental studies demonstrated that air pollution promotes a systemic vascular oxidative stress reaction. Radical oxygen species induce endothelial dysfunction, monocyte activation and some proatherogenic changes in lipoproteins, which initiate plaque formation. Furthermore, air pollution favours thrombus formation, because of an increase in coagulation factors and platelet activation. Experimental studies also indicate that some pollutants have more harmful cardiovascular effects, such as combustion-derived PM 2.5 and ultrafine particles. Air pollution is a major contributor to cardiovascular diseases. Promotion of safer air quality appears to be a new challenge in cardiovascular disease prevention. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Targeted drug delivery to magnetic implants for therapeutic applications

    International Nuclear Information System (INIS)

    Yellen, Benjamin B.; Forbes, Zachary G.; Halverson, Derek S.; Fridman, Gregory; Barbee, Kenneth A.; Chorny, Michael; Levy, Robert; Friedman, Gary

    2005-01-01

    A new method for locally targeted drug delivery is proposed that employs magnetic implants placed directly in the cardiovascular system to attract injected magnetic carriers. Theoretical simulations and experimental results support the assumption that using magnetic implants in combination with externally applied magnetic field will optimize the delivery of magnetic drug to selected sites within a subject

  18. Increased cardiovascular reactivity to acute stress and salt-loading in adult male offspring of fat fed non-obese rats.

    Directory of Open Access Journals (Sweden)

    Olena Rudyk

    Full Text Available Diet-induced obesity in rat pregnancy has been shown previously to be associated with consistently raised blood pressure in the offspring, attributed to sympathetic over-activation, but the relative contributions to this phenotype of maternal obesity versus raised dietary fat is unknown. Sprague-Dawley female rats were fed either a control (4.3% fat, n = 11 or lard-enriched (23.6% fat, n = 16 chow 10 days prior to mating, throughout pregnancy and lactation. In conscious adult (9-month-old offspring cardiovascular parameters were measured (radiotelemetry. The short period of fat-feeding did not increase maternal weight versus controls and the baseline blood pressure was similar in offspring of fat fed dams (OF and controls (OC. However, adult male OF showed heightened cardiovascular reactivity to acute restraint stress (p<0.01; Δ systolic blood pressure (SBP and Δheart rate (HR with a prolonged recovery time compared to male OC. α1/β-adrenergic receptor blockade normalised the response. Also, after dietary salt-loading (8%-NaCl ad libitum for 1 week male OF demonstrated higher SBP (p<0.05 in the awake phase (night-time and increased low/high frequency ratio of power spectral density of HR variability versus OC. Baroreflex gain and basal power spectral density components of the heart rate or blood pressure were similar in male OF and OC. Minor abnormalities were evident in female OF. Fat feeding in the absence of maternal obesity in pregnant rats leads to altered sympathetic control of cardiovascular function in adult male offspring, and hypertension in response to stressor stimuli.

  19. Anisotropy, magnetic field and stress influences on the phase transitions on spin-flop-type antiferromagnets

    International Nuclear Information System (INIS)

    Machado, S.F.; Espirito Santo Univ., Vitoria; Tsallis, C.

    1983-01-01

    Within a mean field approximation, the influences of anisotropy (in the spin space) and external uniaxial stress on the Heisenberg antiferromagnet in the presence of magnetic field are discussed. The phase diagram evolution (as function of anisotropy and stress) which is obtained, enables a satisfactory overall interpretation of recent experiments on Mn(Br sub(1-x) Cl sub(x)) 2 .4H 2 O, K 2 [FeCl 5 (H 2 O)], CoCl 2 .6H 2 O and (C 2 H 5 NH 3 ) 2 CuCl 4 . (Author) [pt

  20. [Beneficial effects of chocolate on cardiovascular health].

    Science.gov (United States)

    Gómez-Juaristi, M; González-Torres, L; Bravo, L; Vaquero, M P; Bastida, S; Sánchez-Muniz, F J

    2011-01-01

    Since ancient times, numerous health beneficial effects have been attributed to chocolate, closing up its consumption to a therapeutic use. The present study reviews some relevant studies about chocolate (and its bioactive compounds) on some cardiovascular risk factors and stresses the need of future studies. The consumption of cocoa/ chocolate (i) increases plasma antioxidant capacity, (ii) diminishes platelet function and inflammation, and (iii) decreases diastolic and systolic arterial pressures. Data currently available indicate that daily consumption of cocoa-rich chocolate (rich in polyphenols) may at least partially lower cardiovascular disease risk. Further studies are required in order to establish the bioavailability and mechanisms of action of bioactive compounds in chocolate. The study of the interaction of chocolate and its components with candidate genes will also supply necessary information regarding the individuals best suited to benefit from a potential cardiovascular disease treatment with chocolate.

  1. Reducing workplace burnout: the relative benefits of cardiovascular and resistance exercise.

    Science.gov (United States)

    Bretland, Rachel Judith; Thorsteinsson, Einar Baldvin

    2015-01-01

    Objectives. The global burden of burnout cost is in excess of $300 billion annually. Locally, just under half of working Australians experience high levels of occupational burnout. Consequently, burnout interventions are paramount to organisational productivity. Exercise has the potential to provide a multilevel and cost effective burnout intervention. The current study aims to extend the literature by comparing cardiovascular with resistance exercise to assess their relative effectiveness against well-being, perceived stress, and burnout. Design. Participants were 49 (36 females and 13 males) previously inactive volunteers ranging in age from 19 to 68 that completed a four week exercise program of either cardiovascular, resistance, or no exercise (control). Randomised control trial design was employed. Method. Participants were measured against the Subjective Exercise Experience Scale, the Perceived Stress Scale, and the Maslach Burnout Inventory. Results. After four weeks of exercise participants had greater positive well-being and personal accomplishment, and concomitantly less psychological distress, perceived stress, and emotional exhaustion. Cardiovascular exercise was found to increase well-being and decrease psychological distress, perceived stress, and emotional exhaustion. Resistance training was noticeably effective in increasing well-being and personal accomplishment and to reduce perceived stress. The present findings revealed large effect sizes suggesting that exercise may be an effective treatment for burnout. However, given a small sample size further research needs to be conducted. Conclusion. Exercise has potential to be an effective burnout intervention. Different types of exercise may assist employees in different ways. Organisations wishing to proactively reduce burnout can do so by encouraging their employees to access regular exercise programs.

  2. Reducing workplace burnout: the relative benefits of cardiovascular and resistance exercise

    Directory of Open Access Journals (Sweden)

    Rachel Judith Bretland

    2015-04-01

    Full Text Available Objectives. The global burden of burnout cost is in excess of $300 billion annually. Locally, just under half of working Australians experience high levels of occupational burnout. Consequently, burnout interventions are paramount to organisational productivity. Exercise has the potential to provide a multilevel and cost effective burnout intervention. The current study aims to extend the literature by comparing cardiovascular with resistance exercise to assess their relative effectiveness against well-being, perceived stress, and burnout.Design. Participants were 49 (36 females and 13 males previously inactive volunteers ranging in age from 19 to 68 that completed a four week exercise program of either cardiovascular, resistance, or no exercise (control. Randomised control trial design was employed.Method. Participants were measured against the Subjective Exercise Experience Scale, the Perceived Stress Scale, and the Maslach Burnout Inventory.Results. After four weeks of exercise participants had greater positive well-being and personal accomplishment, and concomitantly less psychological distress, perceived stress, and emotional exhaustion. Cardiovascular exercise was found to increase well-being and decrease psychological distress, perceived stress, and emotional exhaustion. Resistance training was noticeably effective in increasing well-being and personal accomplishment and to reduce perceived stress. The present findings revealed large effect sizes suggesting that exercise may be an effective treatment for burnout. However, given a small sample size further research needs to be conducted.Conclusion. Exercise has potential to be an effective burnout intervention. Different types of exercise may assist employees in different ways. Organisations wishing to proactively reduce burnout can do so by encouraging their employees to access regular exercise programs.

  3. Significance of radiographic abnormalities in patients with tibial stress injuries: correlation with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kijowski, Richard; Choi, James; Smet, Arthur de; Mukharjee, Rajat

    2007-01-01

    The objective was to correlate radiographic findings with magnetic resonance imaging (MRI) findings in patients with suspected tibial stress injuries in order to determine the significance of radiographic signs of stress injury in these individuals. The study group consisted of 80 patients with suspected tibial stress injuries who underwent a radiographic and MR examination of the tibia. Nineteen patients had bilateral involvement. Thus, a total of 99 tibias were evaluated. All radiographs and MR examinations were retrospectively reviewed, 1 month apart, in consensus by two musculoskeletal radiologists. The radiographs were reviewed without knowledge of the site of the clinical symptoms. Fisher's exact tests were used to determine the association between a positive radiograph and the presence of various MRI signs of a high-grade stress injury. There was a strong association between the presence of periosteal reaction on radiographs at the site of the clinical symptoms and a Fredericson grade 4 stress injury on MRI. The presence of periosteal reaction on radiographs at the site of clinical symptoms is predictive of a high-grade stress injury by MRI criteria. (orig.)

  4. The role of the apelinergic and vasopressinergic systems in the regulation of the cardiovascular system and the pathogenesis of cardiovascular disease.

    Science.gov (United States)

    Czarzasta, Katarzyna; Cudnoch-Jedrzejewska, Agnieszka

    2014-01-01

    Research studies indicate a role of the apelinergic and vasopressinergic systems both in the regulation of the cardiovascular system and the pathogenesis of CVD, including in such settings as obesity and stress. Based on these data, it may be suggested that interactions between these systems underlie numerous physiological and pathophysiological processes, some of them related to the cardiovascular system. Better understanding of the role of these systems and their interactions, both physiological and related to the pathogenesis of CVD, will allow further advances in prevention and drug therapy.

  5. Cardiovascular evaluation in Turner syndrome: utility of MR imaging

    International Nuclear Information System (INIS)

    Dawson-Falk, K.; Bakker, B.; Rosenfeld, R.G.

    1992-01-01

    Forty patients with karyotypically proven Turner syndrome were prospectively studied using magnetic resonance imaging (MRI) and echocardiography in order to determine the frequency of cardiovascular anomalies and to assess the utility of both imaging modalities as methods for cardiovascular evaluation in Turner syndrome. Cardiovascular anomalies were found in 45% of patients. A high absolute prevalence of bicuspid aortic valve (17.5%) and aortic coarctation (12.5%) were observed relative to comparable series. Of clinically significant abnormalities, three of five aortic coarctations and four of five ascending aortic dilatations were solely MRI detected and not evident at echocardiographic examination. MRI is thus seen as a valuable adjunct to echocardiography in the cardiovascular evaluation of Turner syndrome patients. The usefulness of MRI primarily relates to its ability to provide excellent visualisation of the entire thoracic aorta where a large proportion of clinically significant anomalies occur in Turner syndrome. 23 refs., 2 tabs., 5 figs

  6. Cardiovascular evaluation in Turner syndrome: utility of MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dawson-Falk, K; Bakker, B; Rosenfeld, R G [Stanford Univ., CA (United States). School of Medicine

    1992-08-01

    Forty patients with karyotypically proven Turner syndrome were prospectively studied using magnetic resonance imaging (MRI) and echocardiography in order to determine the frequency of cardiovascular anomalies and to assess the utility of both imaging modalities as methods for cardiovascular evaluation in Turner syndrome. Cardiovascular anomalies were found in 45% of patients. A high absolute prevalence of bicuspid aortic valve (17.5%) and aortic coarctation (12.5%) were observed relative to comparable series. Of clinically significant abnormalities, three of five aortic coarctations and four of five ascending aortic dilatations were solely MRI detected and not evident at echocardiographic examination. MRI is thus seen as a valuable adjunct to echocardiography in the cardiovascular evaluation of Turner syndrome patients. The usefulness of MRI primarily relates to its ability to provide excellent visualisation of the entire thoracic aorta where a large proportion of clinically significant anomalies occur in Turner syndrome. 23 refs., 2 tabs., 5 figs.

  7. Postmortem cardiovascular magnetic resonance imaging in fetuses and children: a masked comparison study with conventional autopsy.

    Science.gov (United States)

    Taylor, Andrew M; Sebire, Neil J; Ashworth, Michael T; Schievano, Silvia; Scott, Rosemary J; Wade, Angie; Chitty, Lyn S; Robertson, Nikki; Thayyil, Sudhin

    2014-05-13

    Perinatal and pediatric autopsies have declined worldwide in the past decade. We compared the diagnostic accuracy of postmortem, cardiovascular magnetic resonance (CMR) imaging with conventional autopsy and histopathology assessment in fetuses and children. We performed postmortem magnetic resonance imaging in 400 fetuses and children, using a 1.5-T Siemens Avanto magnetic resonance scanner before conventional autopsy. A pediatric CMR imager reported the CMR images, masked to autopsy information. The pathologists were masked to the information from CMR images. The institutional research ethics committee approved the study, and parental consent was obtained. Assuming a diagnostic accuracy of 50%, 400 cases were required for a 5% precision of estimate. Three cases were excluded from analysis, 2 with no conventional autopsy performed and 1 with insufficient CMR sequences performed. Thirty-eight CMR data sets were nondiagnostic (37 in fetuses ≤24 weeks; 1 in a fetus >24 weeks). In the remaining 359 cases, 44 cardiac abnormalities were noted at autopsy. Overall sensitivity and specificity (95% confidence interval) of CMR was 72.7% (58.2-83.7%) and 96.2% (93.5-97.8%) for detecting any cardiac pathology, with positive and negative predictive values of 72.7% (58.2-83.7%) and 96.2% (93.5-97.8%), respectively. Higher sensitivity of 92.6% (76.6-97.9%), specificity of 99.1% (97.4-99.7%), positive predictive value of 89.3% (72.8-96.3%), and negative predictive value of 99.4% (97.8-99.8%) were seen for major structural heart disease. Postmortem CMR imaging may be a useful alternative to conventional cardiac autopsy in fetuses and children for detecting cardiac abnormalities. http://www.clinicaltrials.gov. Unique identifier: NCT01417962.

  8. Notes on the measurement of stress by resistance gauges in the presence of a magnetic field

    International Nuclear Information System (INIS)

    Armand, G.; Lapujoulade, J.

    1961-01-01

    The technique of stress measurement by resistance gauges is well known. Although it is not yet perfect it possesses many advantages and shows great possibilities. In the presence of a magnetic field the measurement is perturbed by certain phenomena, and we have undertaken to calculate their order of magnitude with a view to establishing the error involved in the measurement. Our problem was to measure the stresses on the various parts of the magnet in the synchrotron Saturne. It is known that the induction passes from a value of about nil to 15000 gauss in 0.8 second, and returns to zero in the same time interval; this cycle recurs every 3.2 seconds. In order to isolate the effects the problem of measurements in a static field will be examined first, after which the results obtained will be extended to the case of dynamic fields. (author) [fr

  9. Right and Left Ventricular Function and Mass in Male Elite Master Athletes: A Controlled Contrast-Enhanced Cardiovascular Magnetic Resonance Study.

    Science.gov (United States)

    Bohm, Philipp; Schneider, Günther; Linneweber, Lutz; Rentzsch, Axel; Krämer, Nadine; Abdul-Khaliq, Hashim; Kindermann, Wilfried; Meyer, Tim; Scharhag, Jürgen

    2016-05-17

    It is under debate whether the cumulative effects of intensive endurance exercise induce chronic cardiac damage, mainly involving the right heart. The aim of this study was to examine the cardiac structure and function in long-term elite master endurance athletes with special focus on the right ventricle by contrast-enhanced cardiovascular magnetic resonance. Thirty-three healthy white competitive elite male master endurance athletes (age range, 30-60 years) with a training history of 29±8 years, and 33 white control subjects pair-matched for age, height, and weight underwent cardiopulmonary exercise testing, echocardiography including tissue-Doppler imaging and speckle tracking, and cardiovascular magnetic resonance. Indexed left ventricular mass and right ventricular mass (left ventricular mass/body surface area, 96±13 and 62±10 g/m(2); Pright ventricular mass/body surface area, 36±7 and 24±5 g/m(2); Pleft ventricular end-diastolic volume and right ventricular end-diastolic volume (left ventricular end-diastolic volume/body surface area, 104±13 and 69±18 mL/m(2); Pright ventricular end-diastolic volume/body surface area, 110±22 and 66±16 mL/m(2); PRight ventricular ejection fraction did not differ between athletes and control subjects (52±8 and 54±6%; P=0.26). Pathological late enhancement was detected in 1 athlete. No correlations were found for left ventricular and right ventricular volumes and ejection fraction with N-terminal pro-brain natriuretic peptide, and high-sensitive troponin was negative in all subjects. Based on our results, chronic right ventricular damage in elite endurance master athletes with lifelong high training volumes seems to be unlikely. Thus, the hypothesis of an exercise-induced arrhythmogenic right ventricular cardiomyopathy has to be questioned. © 2016 American Heart Association, Inc.

  10. Stress Perfusion Coronary Flow Reserve Versus Cardiac Magnetic Resonance for Known or Suspected CAD.

    Science.gov (United States)

    Kato, Shingo; Saito, Naka; Nakachi, Tatsuya; Fukui, Kazuki; Iwasawa, Tae; Taguri, Masataka; Kosuge, Masami; Kimura, Kazuo

    2017-08-15

    Phase-contrast (PC) cine magnetic resonance imaging (MRI) of the coronary sinus is a noninvasive method to quantify coronary flow reserve (CFR). This study sought to compare the prognostic value of CFR by cardiac magnetic resonance (CMR) and stress perfusion CMR to predict major adverse cardiac events (MACE). Participants included 276 patients with known coronary artery disease (CAD) and 400 with suspected CAD. CFR was calculated as myocardial blood flow during adenosine triphosphate infusion divided by myocardial blood flow at rest using PC cine MRI of the coronary sinus. During a median follow-up of 2.3 years, 47 patients (7%) experienced MACE. Impaired CFR (10% ischemia on stress perfusion CMR were significantly associated with MACE in patients with known CAD (hazard ratio [HR]: 5.17 and HR: 5.10, respectively) and suspected CAD (HR: 14.16 and HR: 6.50, respectively). The area under the curve for predicting MACE was 0.773 for CFR and 0.731 for stress perfusion CMR (p = 0.58) for patients with known CAD, and 0.885 for CFR and 0.776 for stress perfusion CMR (p = 0.059) in the group with suspected CAD. In patients with known CAD, sensitivity, specificity, and positive and negative predictive values to predict MACE were 64%, 91%, 38%, and 97%, respectively, for CFR, and 82%, 59%, 15%, and 97%, respectively, for stress perfusion CMR. In the suspected CAD group, these values were 65%, 99%, 80%, and 97%, respectively, for CFR, and 72%, 83%, 22%, and 98%, respectively, for stress perfusion CMR. The predictive values of CFR and stress perfusion CMR for MACE were comparable in patients with known CAD. In patients with suspected CAD, CFR showed higher HRs and areas under the curve than stress perfusion CMR, suggesting that CFR assessment by PC cine MRI might provide better risk stratification for patients with suspected CAD. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  11. Theoretical analysis of magnetic sensor output voltage

    International Nuclear Information System (INIS)

    Liu Haishun; Dun Chaochao; Dou Linming; Yang Weiming

    2011-01-01

    The output voltage is an important parameter to determine the stress state in magnetic stress measurement, the relationship between the output voltage and the difference in the principal stresses was investigated by a comprehensive application of magnetic circuit theory, magnetization theory, stress analysis as well as the law of electromagnetic induction, and a corresponding quantitative equation was derived. It is drawn that the output voltage is proportional to the difference in the principal stresses, and related to the angle between the principal stress and the direction of the sensor. This investigation provides a theoretical basis for the principle stresses measurement by output voltage. - Research highlights: → A comprehensive investigation of magnetic stress signal. → Derived a quantitative equation about output voltage and the principal stresses. → The output voltage is proportional to the difference of the principal stresses. → Provide a theoretical basis for the principle stresses measurement.

  12. Imaging focal and interstitial fibrosis with cardiovascular magnetic resonance in athletes with left ventricular hypertrophy: implications for sporting participation.

    LENUS (Irish Health Repository)

    Waterhouse, Deirdre F

    2012-11-01

    Long-term high-intensity physical activity is associated with morphological changes, termed as the \\'athlete\\'s heart\\'. The differentiation of physiological cardiac adaptive changes in response to high-level exercise from pathological changes consistent with an inherited cardiomyopathy is imperative. Cardiovascular magnetic resonance (CMR) imaging allows definition of abnormal processes occurring at the tissue level, including, importantly, myocardial fibrosis. It is therefore vital in accurately making this differentiation. In this review, we will review the role of CMR imaging of fibrosis, and detail CMR characterisation of myocardial fibrosis in various cardiomyopathies, and the implications of fibrosis. Additionally, we will outline advances in imaging fibrosis, in particular T1 mapping. Finally we will address the role of CMR in pre-participation screening.

  13. Cardiac magnetic resonance: Impact on diagnosis and management of patients with congenital cardiovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Secchi, F., E-mail: francescosecchimd@gmail.com [Scuola di Specializzazione in Radiodiagnostica, Universita degli Studi di Milano, Milan (Italy); Di Leo, G. [S.C. di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese, Milan (Italy); Papini, G.D.E. [Scuola di Specializzazione in Radiodiagnostica, Universita degli Studi di Milano, Milan (Italy); Nardella, V.G. [Facolta di Medicina e Chirurgia, Universita degli Studi di Milano, Milan (Italy); Negura, D.; Carminati, M. [S.C. di Cardiologia Pediatrica, IRCCS Policlinico San Donato, San Donato Milanese, Milan (Italy); Sardanelli, F. [S.C. di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese, Milan (Italy); Dipartimento di Scienze Medico-Chirurgiche, Universita degli Studi di Milano, Milan (Italy)

    2011-08-15

    Aim: To estimate the clinical impact of cardiac magnetic resonance (CMR) in patients with congenital cardiovascular disease (CCD). Materials and methods: Since 2003, 1.5 T CMR was used at our university hospital to evaluate morphology, cardiac kinetics, aortic and pulmonary flow, and vascular anatomy in patients with CCD. The present study considered a consecutive series of these patients from 2003 to 2006. A paediatric cardiologist judged our reports as expected or unexpected and, secondarily, as not reliable (level 0), describing findings already known (level 1), not changing therapy/suggested lifestyle (level 2), changing therapy/suggested lifestyle (level 3) or changing diagnosis (level 4). Results: CMR reports were judged to be expected in 187/214 (87%) and unexpected in 27/214 (13%). Less than 2% of CMRs were judged as levels 0 or 1, 66% as level 2, and 5% as level 4. During 2005-2006 the clinical impact improved toward higher impact levels (p < 0.001, chi-square test). Conclusions: In patients with CCD, more than one in 10 CMR reports were unexpected to cardiologists and over seven in 10 prompted a change of diagnosis or therapy.

  14. Orthostatic stress is necessary to maintain the dynamic range of cardiovascular control in space

    Science.gov (United States)

    Baisch, J. F.; Wolfram, G.; Beck, L.; Drummer, C.; Stormer, I.; Buckey, J.; Blomqvist, G.

    2000-01-01

    In the upright position, gravity fills the low-pressure systems of human circulation with blood and interstitial fluid in the sections below the diaphragm. Without gravity one pressure component in the vessels disappears and the relationship between hydrostatic pressure and oncotic pressure, which regulates fluid passage across the capillary endothelium in the terminal vascular bed, shifts constantly. The visible consequences of this are a puffy face and "bird" legs. The plasma volume shrinks in space and the range of cardiovascular control is reduced. When they stand up for the first time after landing, 30-50% of astronauts suffer from orthostatic intolerance. It remains unclear whether microgravity impairs cardiovascular reflexes, or whether it is the altered volume status that causes the cardiovascular instability following space flight. Lower body negative pressure was used in several space missions to stimulate the cardiovascular reflexes before, during and after a space flight. The results show that cardiovascular reflexes are maintained in microgravity. However, the astronauts' volume status changed in space, towards a volume-retracted state, as measurements of fluid-regulating hormones have shown. It can be hypothesized that the control of circulation and body fluid homeostasis in humans is adapted to their upright posture in the Earth's gravitational field. Autonomic control regulates fluid distribution to maintain the blood pressure in that posture, which most of us have to cope with for two-thirds of the day. A determined amount of interstitial volume is necessary to maintain the dynamic range of cardiovascular control in the upright posture; otherwise orthostatic intolerance may occur more often.

  15. SUSCEPTIBILITY TO OZONE-INDUCED INJURY AND ANTIOXIDANT COMPENSATION IN RAT MODELS OF CARDIOVASCULAR DISEASE

    Science.gov (United States)

    Increased oxidative stress and compromised antioxidant status are common pathologic factors of cardiovascular diseases (CVD). It is hypothesized that individuals with chronic CVD are more susceptible to environmental exposures due to underlying oxidative stress. To determine the ...

  16. Redox signaling in cardiovascular pathophysiology: A focus on hydrogen peroxide and vascular smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Chang Hyun Byon

    2016-10-01

    Full Text Available Oxidative stress represents excessive intracellular levels of reactive oxygen species (ROS, which plays a major role in the pathogenesis of cardiovascular disease. Besides having a critical impact on the development and progression of vascular pathologies including atherosclerosis and diabetic vasculopathy, oxidative stress also regulates physiological signaling processes. As a cell permeable ROS generated by cellular metabolism involved in intracellular signaling, hydrogen peroxide (H2O2 exerts tremendous impact on cardiovascular pathophysiology. Under pathological conditions, increased oxidase activities and/or impaired antioxidant systems results in uncontrolled production of ROS. In a pro-oxidant environment, vascular smooth muscle cells (VSMC undergo phenotypic changes which can lead to the development of vascular dysfunction such as vascular inflammation and calcification. Investigations are ongoing to elucidate the mechanisms for cardiovascular disorders induced by oxidative stress. This review mainly focuses on the role of H2O2 in regulating physiological and pathological signals in VSMC.

  17. Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

    Science.gov (United States)

    AlJaroudi, Wael A; Hage, Fadi G

    2016-02-01

    In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging.

  18. Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques--pulse sequences, analysis algorithms, and applications

    Directory of Open Access Journals (Sweden)

    Ibrahim El-Sayed H

    2011-07-01

    Full Text Available Abstract Cardiovascular magnetic resonance (CMR tagging has been established as an essential technique for measuring regional myocardial function. It allows quantification of local intramyocardial motion measures, e.g. strain and strain rate. The invention of CMR tagging came in the late eighties, where the technique allowed for the first time for visualizing transmural myocardial movement without having to implant physical markers. This new idea opened the door for a series of developments and improvements that continue up to the present time. Different tagging techniques are currently available that are more extensive, improved, and sophisticated than they were twenty years ago. Each of these techniques has different versions for improved resolution, signal-to-noise ratio (SNR, scan time, anatomical coverage, three-dimensional capability, and image quality. The tagging techniques covered in this article can be broadly divided into two main categories: 1 Basic techniques, which include magnetization saturation, spatial modulation of magnetization (SPAMM, delay alternating with nutations for tailored excitation (DANTE, and complementary SPAMM (CSPAMM; and 2 Advanced techniques, which include harmonic phase (HARP, displacement encoding with stimulated echoes (DENSE, and strain encoding (SENC. Although most of these techniques were developed by separate groups and evolved from different backgrounds, they are in fact closely related to each other, and they can be interpreted from more than one perspective. Some of these techniques even followed parallel paths of developments, as illustrated in the article. As each technique has its own advantages, some efforts have been made to combine different techniques together for improved image quality or composite information acquisition. In this review, different developments in pulse sequences and related image processing techniques are described along with the necessities that led to their invention

  19. Multistructure index in revealing complexity of regulatory mechanisms of human cardiovascular system at rest and orthostatic stress in healthy humans

    Science.gov (United States)

    Makowiec, Danuta; Graff, Beata; Struzik, Zbigniew R.

    2017-02-01

    Biological regulation is sufficiently complex to pose an enduring challenge for characterization of both its equilibrium and transient non-equilibrium dynamics. Two univariate but coupled observables, heart rate and systolic blood pressure, are commonly characterized in the benchmark example of the human cardiovascular regulatory system. Asymmetric distributions of accelerations and decelerations of heart rate, as well as rises and falls in systolic blood pressure, recorded in humans during a head-up tilt test provide insights into the dynamics of cardiovascular response to a rapid, controlled deregulation of the system's homeostasis. The baroreflex feedback loop is assumed to be the fundamental physiological mechanism for ensuring homeostatic blood supply to distant organs at rest and during orthostatic stress, captured in a classical beat-to-beat autoregressive model of baroreflex by de Boer et al. (1987). For model corroboration, a multistructure index statistic is proposed, seamlessly evaluating the size spectrum of magnitudes of neural reflexes such as baroreflex, responsible for maintaining the homeostatic dynamics. The multistructure index exposes a distinctly different dynamics of multiscale asymmetry between results obtained from real-life signals recorded from healthy subjects and those simulated using both the classical and perturbed versions of the model. Nonlinear effects observed suggest the pronounced presence of complex mechanisms resulting from baroreflex regulation when a human is at rest, which is aggravated in the system's response to orthostatic stress. Using our methodology of multistructure index, we therefore show a marked difference between model and real-life scenarios, which we attribute to multiscale asymmetry of non-linear origin in real-life signals, which we are not reproducible by the classical model.

  20. Role of quercetin in cardiovascular diseases | Lakhanpal | Internet ...

    African Journals Online (AJOL)

    Cardiovascular disease constitutes a major public health concern in industrialized nations. Over recent decades, a large body of evidence has accumulated indicating that oxidative stress induced free radicals play a critical role in cellular processes implicated in atherosclerosis and many other heart diseases. However a ...

  1. Effects of Exercise on Cardiovascular Dysfunctions Induced by Cigarette Smoking

    Directory of Open Access Journals (Sweden)

    Abdel-Sater Khaled A.

    2008-06-01

    Full Text Available Smoking is known to adversely affect many organs and systems in human, where the cardiovascular system is