Search results for "ventricle"
showing 10 items of 431 documents
Prediction of CRT Activation Sequence by Personalization of Biventricular Models from Electroanatomical Maps
2020
[EN] Optimization of lead placement and interventricular delay settings in patients under cardiac resynchronization therapy is a complex task that might benefit from prior information based on models. Biophysical models can be used to predict the sequence of electrical heart activation in a patient given a set of parameters which should be personalized to the patient. In this paper, we use electroanatomical maps to personalize the endocardial activation of the right ventricle, and the different tissue conductivities in a pig model with left bundle branch block, to reproduce personalized biventricular activations. Following, we tested the personalized heart model by virtually simulating card…
Cardiomyocyte apoptosis is related to left ventricular dysfunction and remodelling in dilated cardiomyopathy, but is not affected by growth hormone t…
2007
Background and aims Cardiomyocyte apoptosis (CA) is a common feature of end-stage heart failure. We examined whether CA is associated with cardiac dysfunction and remodelling in heart failure due to dilated cardiomyopathy and studied the effect of human growth hormone (hGH) on CA. Methods and results We studied 38 patients, included in a phase III multi-center, randomised, double-blind and placebo-controlled trial of biosynthetic hGH treatment in dilated cardiomyopathy, at baseline and after 14 weeks treatment. Twenty-six patients received hGH and 12 received placebo. CA was quantified in endomyocardial biopsies using the TUNEL assay. CA correlated with left ventricular size (r=0.43, p=0.00…
Segmental dyskinesia in Wolff–Parkinson–White syndrome: A possible cause of dilatative cardiomyopathy
2006
Wolff-Parkinson-White (WPW) is a syndrome characterized by the presence of an accessory pathway that skipping A-V node may lead the electrical stimulus from the atrium directly to the ventricle. Some studies reported the finding of myocardial dyskinesia in the segments precociously activated by the accessory pathway, at echocardiogram and at nuclear cardiac study. Soria et al. reported, in 1985, an increased incidence of dilative cardiomyopathy in patients with WPW. The pathophysiological pathway that leads to ventricular dilation may be due to the increase of end-diastolic pressure secondary to a tachycardia-induced cardiomyopathy. Tachycardia-induced cardiomyopathy is usually secondary to…
High-resolution mouse subventricular zone stem-cell niche transcriptome reveals features of lineage, anatomy, and aging
2020
Adult neural stem cells (NSC) serve as a reservoir for brain plasticity and origin for certain gliomas. Lineage tracing and genomic approaches have portrayed complex underlying heterogeneity within the major anatomical location for NSC, the subventricular zone (SVZ). To gain a comprehensive profile of NSC heterogeneity, we utilized a well-validated stem/progenitor-specific reporter transgene in concert with single-cell RNA sequencing to achieve unbiased analysis of SVZ cells from infancy to advanced age. The magnitude and high specificity of the resulting transcriptional datasets allow precise identification of the varied cell types embedded in the SVZ including specialized parenchymal cell…
Primary Neural Precursors and Intermitotic Nuclear Migration in the Ventricular Zone of Adult Canaries
1998
New neurons continue to be born in the ventricular zone (VZ) of the lateral ventricles in the brain of adult birds. On the basis of serial section reconstruction and electron microscopy, we determined that the VZ of the adult canary brain is composed of three main cell types (A, B, and E). Type A cells were never found in contact with the ventricle and had microtubule-rich processes typical of young migrating neurons. Type B cells were organized as a pseudostratified epithelium, all contacted the ventricle, and most had a characteristic single cilium. Type E cells, also in contact with ventricle, were ultrastructurally similar to the mammalian multiciliated ependymal cells. After six inject…
Axonal control of the adult neural stem cell niche.
2014
SummaryThe ventricular-subventricular zone (V-SVZ) is an extensive germinal niche containing neural stem cells (NSCs) in the walls of the lateral ventricles of the adult brain. How the adult brain’s neural activity influences the behavior of adult NSCs remains largely unknown. We show that serotonergic (5HT) axons originating from a small group of neurons in the raphe form an extensive plexus on most of the ventricular walls. Electron microscopy revealed intimate contacts between 5HT axons and NSCs (B1) or ependymal cells (E1) and these cells were labeled by a transsynaptic viral tracer injected into the raphe. B1 cells express the 5HT receptors 2C and 5A. Electrophysiology showed that acti…
Postnatal neurogenesis in the medial cortex of the tropical lizard Tropidurus hispidus.
2004
Young, adult and presumed old specimens of the tropical lizard Tropidurus hispidus, living in an almost steady warm habitat, have been the subjects of a 5-bromodeoxiuridine immunocytochemical study to label proliferating brain cells. All animals showed abundant 5-bromodeoxiuridine-labeled nuclei in the ependyma of their telencephalic lateral ventricles, with these being especially abundant in the medial cortex ependyma. Surprisingly, adult animals displayed higher numbers of labeled nuclei when compared with those of young specimens. In a second experiment, in order to check the evolution of ependymal-labeled nuclei, adult specimens were allowed 4 h or 2, 4, 7, 15 or 30 days of survival aft…
Multimodal Simulation of a Novel Device for a Safe and Effective External Ventricular Drain Placement
2021
BackgroundExternal ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD varies widely in literature, ranging from 12.3 to 60%. The purpose of this simulation study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.MethodsWe used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans. The data sets were used to conduct three-dimensional computer-based and combined navigation and augmented reality-based simulations using pla…
Dynamic Changes in the Neurogenic Potential in the Ventricular–Subventricular Zone of Common Marmoset during Postnatal Brain Development
2020
AbstractEven after birth, neuronal production continues in the ventricular–subventricular zone (V–SVZ) and hippocampus in many mammals. The immature new neurons (“neuroblasts”) migrate and then mature at their final destination. In humans, neuroblast production and migration toward the neocortex and the olfactory bulb (OB) occur actively only for a few months after birth and then sharply decline with age. However, the precise spatiotemporal profiles and fates of postnatally born neurons remain unclear due to methodological limitations. We previously found that common marmosets, small nonhuman primates, share many features of V–SVZ organization with humans. Here, using marmosets injected wit…
Automatic left ventricle volume calculation with explainability through a deep learning weak-supervision methodology
2021
[EN] Background and objective: Magnetic resonance imaging is the most reliable imaging technique to assess the heart. More specifically there is great importance in the analysis of the left ventricle, as the main pathologies directly affect this region. In order to characterize the left ventricle, it is necessary to extract its volume. In this work we present a neural network architecture that is capable of directly estimating the left ventricle volume in short axis cine Magnetic Resonance Imaging in the end-diastolic frame and provide a segmentation of the region which is the basis of the volume calculation, thus offering explain-ability to the estimated value. Methods: The network was des…