Search results for "ventricles"
showing 10 items of 261 documents
Exercise stress CMR reveals reduced aortic distensibility and impaired right-ventricular adaptation to exercise in patients with repaired tetralogy o…
2018
International audience; The aim of our study was to evaluate the feasibility of exercise cardiac magnetic resonance (CMR) in patients with repaired tetralogy of Fallot (RTOF) and to assess right and left ventricular adaptation and aortic wall response to exercise in comparison with volunteers.Methods11 RTOF and 11 volunteers underwent prospective CMR at rest and during exercise. A supine bicycle ergometer was employed to reach twice the resting heart rate during continuous exercise, blood pressure and heart rate were recorded. Bi-ventricular parameters and aortic stiffness were assessed using accelerated cine sequences and flow-encoding CMR. A t-test was used to compare values between group…
Different mechanisms of the inhibition of the transient outward current in rat ventricular myocytes.
1994
The mechanism of drug-induced inhibition of the transient outward current, Ito, has been investigated in rat ventricular myocytes using the whole cell patch clamp technique. Ito was activated by 300 ms depolarizing voltage clamp steps in 10 mV increments from −50 mV up to +40 mV. At +40 mV, Ito peaked after about 3 ms, and the time course of inactivation was appropriately described by two time constants, τfast = 17 ms and τslow = 203 ms. Verapamil, quinidine sulfate and nifedipine preferentially depressed Ito at the end of the 300 ms depolarizing voltage clamp step; the inactivation of Ito was accelerated by all drugs, whereas peak Ito was less affected. The time course of drug action at +4…
Nociceptive Primitive Reflexes in Neurologically and Cognitively Healthy Aging Subjects
2019
ABSTRACT:Background:To assess the prevalence of three nociceptive primitive reflexes (nPR), i.e., glabellar tap, snout reflex, and palmomental reflex, in neurologically and cognitively healthy (NCH) aging subjects.Objective:To investigate whether nPR are cross-sectionally associated with white matter hyperintensities (WMH), lacunes, atrophy of the caudate nuclei, and global brain atrophy.Methods:A total of 1246 NCH subjects aged 45–91 years were included in the study and underwent standard brain MRI. Atrophy of the caudate nuclei and global brain atrophy were assessed through the bicaudate ratio (BCr) and lateral ventricles to brain ratio (LVBr), respectively. WMH were assessed through visu…
Hypoxia and myocardial remodeling in human cardiac allografts: a time-course study.
2009
Background: Cardiac allografts are known to develop myocardial fibrosis, which may be a cause of progressive cardiac dysfunction. Apart from the renin‐angiotensin and transforming growth factor- system, hypoxia has been proposed as an important player in the pathogenesis of fibrosis, but its significance remains unclear. This study examines the degree of myocardial fibrosis, cellular remodeling and hypoxic signaling over a time-course of 10 years after human cardiac allograft transplantation. Methods: Serial right ventricular biopsies of 57 patients were collected in 6-month intervals after cardiac transplant surgery for a total of 10 years to allow a retrospective longitudinal analysis. Ov…
Normal Reference Ranges for Echocardiography: Rationale, study design, and methodology (NORRE Study)
2013
International audience; BACKGROUND: Availability of normative reference values for cardiac chamber dimensions, volumes, mass, and function is a prerequisite for the accurate application of echocardiography for both clinical and research purposes. However, due to the lack of consistency in current echocardiographic 'reference values', their use for clinical decision-making remains questionable. AIMS: The aim of the 'Normal Reference Ranges for Echocardiography Study (NORRE Study)' is to obtain a set of 'normal values' for cardiac chamber geometry and function in a large cohort of healthy Caucasian individuals aged over a wide range of ages (25-75 years) using both conventional and advanced e…
Anticoagulant drugs in noncompaction: A mandatory therapy?
2008
BACKGROUND: Noncompaction of left ventricular myocardium is a rare congenital cardiomyopathy resulting from an incomplete myocardial morphogenesis that leads to the persistence of the embryonic myocardium. This condition is characterized by a thin compacted epicardial and an extremely thickened endocardial layer with prominent trabeculations and deep intertrabecular recesses. It is not clear, in noncompaction of myocardium, whether intertrabecular recesses could be responsible for thrombi formation and thromboembolic complications. METHODS: The prevalence of stroke and echocardiographic finding of thrombus was evaluated in a continuous series of 229 patients (men and women) affected by nonc…
Prognostic Implications of Tissue Doppler Imaging-Derived E/Ea Ratio in Acute Heart Failure Patients
2014
Background Tissue Doppler–derived transmitral to mitral annular early diastolic velocity ratio (E/Ea), as a noninvasive estimation of left ventricular (LV) filling pressures, is a strong prognosticator in various cardiac scenarios including chronic heart failure; nevertheless, its utility for risk stratification in the whole spectrum of acute heart failure (AHF) patients remains elusive. Thus, the aim of this study was to determine the association between E/Ea ratio and 1-year mortality in nonselected patients with AHF. Methods The study included 417 consecutive patients admitted for AHF. Twenty-two patients were excluded due to nonaccurate Ea measurements, leaving the final sample to be 39…
Cellular composition and three-dimensional organization of the subventricular germinal zone in the adult mammalian brain.
1997
The adult mammalian subventricular zone (SVZ) contains stem cells that give rise to neurons and glia.In vivo, SVZ progeny migrate 3–8 mm to the olfactory bulb, where they form neurons. We show here that the SVZ of the lateral wall of the lateral ventricles in adult mice is composed of neuroblasts, glial cells, and a novel putative precursor cell. The topographical organization of these cells suggests how neurogenesis and migration are integrated in this region. Type A cells had the ultrastructure of migrating neuronal precursors. These cells were arranged as chains parallel to the walls of the ventricle and were polysialylated neural adhesion cell molecule- (PSA–NCAM), TuJ1- (β-tubulin), an…
Subventricular Zone Astrocytes Are Neural Stem Cells in the Adult Mammalian Brain
1999
AbstractNeural stem cells reside in the subventricular zone (SVZ) of the adult mammalian brain. This germinal region, which continually generates new neurons destined for the olfactory bulb, is composed of four cell types: migrating neuroblasts, immature precursors, astrocytes, and ependymal cells. Here we show that SVZ astrocytes, and not ependymal cells, remain labeled with proliferation markers after long survivals in adult mice. After elimination of immature precursors and neuroblasts by an antimitotic treatment, SVZ astrocytes divide to generate immature precursors and neuroblasts. Furthermore, in untreated mice, SVZ astrocytes specifically infected with a retrovirus give rise to new n…
Postnatal neurogenesis in the telencephalon of turtles: evidence for nonradial migration of new neurons from distant proliferative ventricular zones …
1997
Postnatal neurogenesis in the the turtle telencephalon was investigated by using bromodeoxyuridine immunocytochemistry and [3H]thymidine autoradiography. Red-eared slider turtles Trachemys scripta elegans (Cryptodira, Emydidae) 2-3 months old were injected with the thymidine analogue 5'-bromodeoxyuridine (BrdU) and allowed to survive for 7, 30, 90, and 180 days. Results indicate that cells in the walls of the lateral ventricles continue to proliferate postnatally. Shortly after BrdU treatment (seven days) most labelled cells were found in the walls of the lateral ventricles (ventricular zone: VZ). Labelled cells were particularly abundant in and around the ventricular sulci. The same patter…