Search results for "Pressure"
showing 10 items of 4493 documents
Inhibition of class I histone deacetylase with an apicidin derivative prevents cardiac hypertrophy and failure
2008
AIMS: Recent studies have demonstrated the importance of chromatin remodelling via histone acetylation/deacetylation for the control of cardiac gene expression. Specific histone deacetylases (HDACs) can, in fact, play a positive or negative role in determining cardiac myocyte (CM) size. Here, we report on the effect on hypertrophy development of three inhibitors (HDACi) of class I HDACs. METHODS AND RESULTS: The compounds were first analysed in vitro by scoring hypertrophy, expression of foetal genes, and apoptosis of neonatal rat CMs stimulated with phenylephrine, an alpha1-adrenergic agonist. This initial screening indicated that a truncated derivative of apicidin with class I HDAC specif…
Long-term cardiac pro-B-type natriuretic peptide gene delivery prevents the development of hypertensive heart disease in spontaneously hypertensive r…
2011
Background— Diastolic dysfunction associated with high blood pressure (BP) leads to cardiac remodeling and fibrosis and progression to congestive heart failure. B-type natriuretic peptide (BNP) has BP-lowering, antifibrotic, and antihypertrophic properties, which makes BNP an attractive agent for attenuating the adverse cardiac remodeling associated with hypertension. In the current study, we tested the effects of sustained cardiac proBNP gene delivery on BP, cardiac function, and remodeling in spontaneously hypertensive rats (SHR). Methods and Results— We used the myocardium-tropic adeno-associated virus serotype 9 (AAV9) vector to achieve continuously enhanced cardiac rat proBNP expressi…
Association of Arsenic Exposure With Cardiac Geometry and Left Ventricular Function in Young Adults
2019
Background: Arsenic exposure has been related to numerous adverse cardiovascular outcomes. The aim of this study was to investigate the cross-sectional and prospective association between arsenic exposure with echocardiographic measures of left ventricular (LV) geometry and functioning. Methods: A total of 1337 young adult participants free of diabetes mellitus and cardiovascular disease were recruited from the SHFS (Strong Heart Family Study). The sum of inorganic and methylated arsenic concentrations in urine (ΣAs) at baseline was used as a biomarker of arsenic exposure. LV geometry and functioning were assessed using transthoracic echocardiography at baseline and follow-up. Results: Mea…
Evaluation of Hemodynamic Parameters for Adaptive Control of the Artificial Heart by Simulation of the Vascular System
1984
Abstract A nonlinear dynamic mathematical model of the cardiovascular system is outlined, which is employable to analyse the hemodynamic system behaviour under normal as well as under pathological conditions. By modifying this model, assuming that cardiac output is constant at a preset level (which is in accordance with most of the total artificial heart systems, since their pumps output is preselected with fixed driving parameters), the hemodynamic behaviour of a circulation system with an artificial heart was simulated. Comparing the simulation results with those obtained from total artificial heart experiments, a good agreement in right atrial and aortic pressure under exercise condition…
Hemodynamic Parameters Change Earlier Than Tissue Oxygen Tension in Hemorrhage
2010
BACKGROUND: Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS: Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after p…
Pulmonary haemodynamics in obstructive sleep apnoea.
1995
In patients with obstructive sleep apnoea syndrome (OSAS), pulmonary haemodynamics can show both transient perturbations during sleep and permanent alterations. During sleep, repeated fluctuations in pulmonary artery pressure and pulmonary wedge pressure, coincident with apnoeas, can be observed. Calculation of transmural pressure values is preferable to intravascular pressures in OSAS, due to the marked swings in intrathoracic pressure associated with obstructive apnoeas. Pulmonary artery pressure may progressively increase during sleep, particularly in close sequences of highly desaturating apnoeas. Apnoea-induced hypoxia appears as the most important determinant of this pulmonary artery …
Structural and Mechanical Characteristics of the Heart of the Icefish Chionodraco hamatus (Lönnberg)
1991
The absence of haemoglobin from the blood of icefish, antarctic teleosts of the family Chaenichthydae, has stimulated important physiological mechanisms which serve to compensate for the absence of the respiratory pigment. In view of the central role played by the circulation in meeting the oxygen demands of the tissues, it is not surprising to find that the cardiocirculatory system has been extensively remodelled in icefish. These adaptations include: (1) increases in blood volume, from two to four times larger than that in many teleosts (Hemmingsen and Douglas 1970; Holeton 1970); (2) increases in blood flow associated with lowered oxygen demands (Hemmingsen and Douglas 1970; Holeton 1970…
Comparison between doppler-echocardiography and uncalibrated pulse contour method for cardiac output measurement. a multicenter observational study
2016
Objectives: Echocardiography and pulse contour methods allow, respectively, noninvasive and less invasive cardiac output estimation. The aim of the present study was to compare Doppler echocardiography with the pulse contour method MostCare for cardiac output estimation in a large and nonselected critically ill population. Design: A prospective multicenter observational comparison study. Setting: The study was conducted in 15 European medicosurgical ICUs. Patients: We assessed cardiac output in 400 patients in whom an echocardiographic evaluation was performed as a routine need or for cardiocirculatory assessment. Interventions: None. Measurements and Main Results: One echocardiographic car…
Ultrasonography in Heart Failure: A Story that Matters
2019
Abstract Heart failure (HF) is a clinical syndrome caused by structural and/or functional cardiac abnormalities, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress. It is the leading cause of hospitalization in Internal Medicine departments. This article aims at reviewing evidence of the importance of ultrasound in HF both for hospitalized patients and in the follow-up. Ultrasound may be used as a recovery monitoring instrument at the bedside and also as a global cardiovascular assessment tool for these patients. HF represents an exciting opportunity to create an integrative ultrasound approach in Internal Medicine and/or Geriatric departme…
Ability of short-time Fourier transform method to detect transient changes in vagal effects on hearts: a pharmacological blocking study.
2006
Conventional spectral analyses of heart rate variability (HRV) have been limited to stationary signals and have not allowed the obtainment of information during transient autonomic cardiac responses. In the present study, we evaluated the ability of the short-time Fourier transform (STFT) method to detect transient changes in vagal effects on the heart. We derived high-frequency power (HFP, 0.20–0.40 Hz) as a function of time during active orthostatic task (AOT) from the sitting to standing posture before and after selective vagal (atropine sulfate 0.04 mg/kg) and sympathetic (metoprolol 0.20 mg/kg) blockades. The HFP minimum point during the first 30 s after standing up was calculated and…