Gamma-actin is required for cytoskeletal maintenance but not development.

Beta(cyto)-actin and gamma(cyto)-actin are ubiquitous proteins thought to be essential building blocks of the cytoskeleton in all non-muscle cells. Despite this widely held supposition, we show that gamma(cyto)-actin null mice (Actg1(-/-)) are viable. However, they suffer increased mortality and show progressive hearing loss during adulthood despite compensatory up-regulation of beta(cyto)-actin.

Pulmonary valve replacement in tetralogy of Fallot: impact on survival and ventricular tachycardia.

Background: Pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (TOF) reduces pulmonary regurgitation and decreases right ventricular (RV) dilation, but its long-term impact on ventricular tachycardia (VT) and mortality is unknown. This study aimed to determine the incidence of death and VT in TOF after PVR and to test the hypothesis that PVR leads to improvement in these outcomes.

Methods And Results: A total of 98 patients with TOF and late PVR for RV dilation were identified.

Human metapneumovirus infections in adults: another piece of the puzzle.

Background: Each winter respiratory viruses account for a significant proportion of serious respiratory illness, including hospitalization, in older adults and those with underlying medical conditions. We describe the incidence and clinical impact of human metapneumovirus (HMPV), a newly identified virus, in adults.

Methods: Infection with HMPV was identified in 3 prospectively enrolled adult cohorts (young persons 19-40 years old, healthy adults > or =65 years old, and high-risk adults) and a hospitalized cohort for 4 consecutive winters (November 15 through April 15 for the years 1999 through 2003).

Video-assisted thoracoscopic cardiac denervation: a potential novel therapeutic option for children with intractable ventricular arrhythmias.

Background: Left cardiac sympathetic denervation is one of the therapeutic modalities used in the management of patients with medically refractory long QT syndrome. Traditionally, a thoracotomy or cervical incision has been used as the standard surgical approach for performing left cardiac sympathetic denervation. Video-assisted thoracoscopic surgery allows a minimally invasive technique.

Ascending aortic dilation in patients with congenital complete heart block.

Background: The clinical spectrum and underlying pathophysiology of isolated congenital complete heart block (CCHB) remain incompletely understood. Aortic dilation has been anecdotally observed in some children with CCHB, but detailed reports are lacking.

Objective: This study sought to systematically describe aortic size in children with CCHB and to investigate predictor variables associated with aortic dilation.

Atrioventricular nodal reentrant tachycardia with 2:1 block in pediatric patients.

Background: Episodic 2:1 block occurs in 9% of adults with atrioventricular nodal reentry tachycardia (AVNRT), but developmental differences in conduction physiology among children could influence this phenomenon.

Objective: This study sought to characterize the frequency and mechanism of 2:1 block during AVNRT in the pediatric population.

Methods: Records of 179 patients (mean age 13.

Comparison of the safety and immunogenicity of 2 respiratory syncytial virus (rsv) vaccines--nonadjuvanted vaccine or vaccine adjuvanted with alum--given concomitantly with influenza vaccine to high-risk elderly individuals.

Background: Respiratory syncytial virus (RSV) has been recognized recently as an important adult pathogen.

Methods: This randomized, double-blind, placebo-controlled study was designed to compare humoral responses to licensed trivalent influenza vaccine given concomitantly with 1 of 2 RSV vaccine formulations in persons > or =65 years old with cardiopulmonary disease. Hemagglutinin-inhibition assays and neutralization assays were used to measure levels of antibody to influenza and RSV, respectively.

The influence of thyroid hormone deficiency on the development of cochlear nonlinearities.

It is well known that failure to treat severe congenital hypothyroidism leads to profound auditory disability, and it has been suggested that an intracochlear defect, or defects, associated with the condition diminishes the efficacy of an active, physiologically vulnerable nonlinear transduction process commonly referred to as cochlear amplification. We address this question directly by tracking the development of threshold-frequency (tuning) curves and two-tone suppression in hypothyroid, Tshr mutant mice born to hypothyroid dams and comparing those findings with findings observed in euthyroid mice. Like sharp tuning, two-tone suppression is a product of transduction nonlinearity and is a useful indicator of the functional status of cochlear amplification.

Assessment of passive cardiovascular implant devices for MRI compatibility.

Purpose: The increasing popularity of both magnetic resonance angiography and minimally invasive cardiovascular interventional procedures has led to the requirement for the development of implant devices that not only provide for patient safety, but produce minimal artifacts in diagnostic images. The purpose of this paper is to assess and discuss physical principles and ASTM testing standards related to the MRI compatibility of implanted devices.

Analysis And Review Of Imaging Compatibility And Safety Of Common Implants And Devices: Standard procedures are described to assess safety and ability to image near implanted stents and heart valves made from different materials and of varying geometry.

Cardiac resynchronization therapy (and multisite pacing) in pediatrics and congenital heart disease: five years experience in a single institution.

Introduction: Clinical evidence supports the use of cardiac resynchronization therapy (CRT) in adults with heart failure, but experience in pediatrics and congenital heart disease (CHD) is limited in terms of patient numbers and follow-up. We sought to determine the functional assessment and clinical outcomes in pediatric and CHD CRT patients followed uniformly at one institution.

Methods: Retrospective review of 60 consecutive patients who underwent CRT between 2002 and 2007.

Cardiac conduction disturbances and ventricular tachycardia after prolonged propofol infusion in an infant.

We report an infant who, after prolonged intravenous propofol infusion for treatment of status epilepticus, developed dramatic cardiac conduction disturbances and tachyarrhythmias in the setting of only mild metabolic acidosis and good ventricular function. Certain electrocardiographic findings were similar to those observed in the Brugada syndrome as well as in adult patients with propofol toxicity who suffered fatal ventricular arrhythmias. This case illustrates that serious arrhythmias can occur during prolonged high-dose propofol infusion in young patients, probably through a direct electrophysiologic membrane effect.

Ectopic atrial rhythm is a preablation predictor of atrioventricular nodal reentrant tachycardia in children.

Background: Supraventricular tachycardia (SVT) is a common tachyarrhythmia among pediatric patients. Usually, non-preexcited SVT is attributable to either atrioventricular nodal reentry tachycardia (AVNRT) or unidirectional retrograde accessory pathway (URAP), but these cannot be differentiated on a baseline electrocardiogram (ECG). The ability to identify the SVT mechanism in children may guide decision-making about treatment and counseling regarding electrophysiology study (EPS).

Results of a multicenter retrospective implantable cardioverter-defibrillator registry of pediatric and congenital heart disease patients.

Objectives: We sought to determine the implications of implantable cardioverter-defibrillator (ICD) placement in children and patients with congenital heart disease (CHD).

Background: There is increasing frequency of ICD use in pediatric and CHD patients. Until recently, prospective registry enrollment of ICD patients was not available, and children and CHD patients account for only a small percentage of ICD recipients.

Digital music players cause interference with interrogation telemetry for pacemakers and implantable cardioverter-defibrillators without affecting device function.

Background: Concern exists regarding the potential electromagnetic interaction between pacemakers, implantable cardioverter-defibrillators (ICDs) and digital music players (DMPs). A preliminary study reported interference in 50% of patients whose devices were interrogated near Apple iPods.

Objective: Given the high prevalence of DMP use among young patients, we sought to define the nature of interference from iPods and evaluate other DMPs.

Practical aspects of implantable defibrillator therapy in patients with congenital heart disease.

Improved awareness of the risk for malignant ventricular arrhythmias in patients with congenital heart disease (CHD), together with dramatic advances in implantable cardioverter-defibrillator (ICD) technology, have led to a rapid increase in device therapy for this population. Clinical challenges remain surrounding patient selection and difficulties with lead positioning that arise in response to the anatomic and physiologic complexities of CHD. This article will attempt to review contemporary data on ICD use in the CHD population with particular attention to the novel implant methodology required for many of these patients.

How revealing are insertable loop recorders in pediatrics?

Introduction: An insertable loop recorder (ILR) in patients with infrequent syncope or palpitations may be useful to decide management strategies, including clinical observation, medical therapy, pacemaker, or implantable cardioverter defibrillator (ICD). We sought to determine the diagnostic utility of the Reveal ILR (Medtronic, Inc., Minneapolis, MN, USA) in pediatric patients.

Monodisperse magnetite nanoparticles coupled with nuclear localization signal peptide for cell-nucleus targeting.

Functionalization of monodisperse superparamagnetic magnetite (Fe(3)O(4)) nanoparticles for cell specific targeting is crucial for cancer diagnostics and therapeutics. Targeted magnetic nanoparticles can be used to enhance the tissue contrast in magnetic resonance imaging (MRI), to improve the efficiency in anticancer drug delivery, and to eliminate tumor cells by magnetic fluid hyperthermia. Herein we report the nucleus-targeting Fe(3)O(4) nanoparticles functionalized with protein and nuclear localization signal (NLS) peptide.

Long-term survival, modes of death, and predictors of mortality in patients with Fontan surgery.

Background: To better define determinants of mortality in patients with univentricular physiology, a database registry was created of patients born in 1985 or earlier with Fontan surgery who were followed up at Children's Hospital Boston.

Methods And Results: A total of 261 patients, 121 of whom (46.4%) were women, had a first Fontan surgery at a median age of 7.

Impact of transvenous ventricular pacing leads on tricuspid regurgitation in pediatric and congenital heart disease patients.

Introduction: Transvenous ventricular pacing leads across the tricuspid valve may cause or exacerbate tricuspid regurgitation (TR). The literature in adults is inconclusive and no studies have investigated the association between pacing leads and TR in children or congenital heart disease patients.

Methods And Results: A retrospective chart review was conducted at a large children's hospital, yielding 123 patients with initial placement of a transvenous lead across their tricuspid valve that had adequate echocardiographic data for review.

Development of cochlear amplification, frequency tuning, and two-tone suppression in the mouse.

It is generally believed that the micromechanics of active cochlear transduction mature later than passive elements among altricial mammals. One consequence of this developmental order is the loss of transduction linearity, because an active, physiologically vulnerable process is superimposed on the passive elements of transduction. A triad of sensory advantage is gained as a consequence of acquiring active mechanics; sensitivity and frequency selectivity (frequency tuning) are enhanced and dynamic operating range increases.

A novel Usher protein network at the periciliary reloading point between molecular transport machineries in vertebrate photoreceptor cells.

The human Usher syndrome (USH) is the most frequent cause of combined deaf-blindness. USH is genetically heterogeneous with at least 12 chromosomal loci assigned to three clinical types, USH1-3. Although these USH types exhibit similar phenotypes in human, the corresponding gene products belong to very different protein classes and families.