Publications by authors named "Richard Derksen"

Aims: This study was performed to develop and externally validate prediction models for appropriate implantable cardioverter-defibrillator (ICD) shock and mortality to identify subgroups with insufficient benefit from ICD implantation.

Methods And Results: We recruited patients scheduled for primary prevention ICD implantation and reduced left ventricular function. Bootstrapping-based Cox proportional hazards and Fine and Gray competing risk models with likely candidate predictors were developed for all-cause mortality and appropriate ICD shock, respectively.

View Article and Find Full Text PDF

Purpose: This study tested the null hypothesis that phosphate-treated titanium implants would perform no differently on mineral apposition rates (MARs), new bone-to-implant contact (new BIC), and total bone-to-implant contact (total BIC) compared to standard titanium implants.

Materials And Methods: Forty 3.3×8.

View Article and Find Full Text PDF

Acquired coronary artery fistulas (CCFs) are infrequently detected during conventional coronary angiography. To delineate the characteristics of congenital (first part) and acquired (second part) CCFs in adults, a PubMed search was conducted for papers dealing with congenital or acquired CCFs. None of the publications describing patients with coronary-vascular fistulas were included.

View Article and Find Full Text PDF

This is a case series and review of the literature adding 11 new cases. Coronary-cameral fistulas (CCFs) are infrequent anomalies which are in general co-incidentally found during diagnostic coronary angiography (CAG). To delineate the characteristics of congenital and acquired CCFs in adults, we performed a PubMed search for papers dealing with congenital or acquired CCFs in adults.

View Article and Find Full Text PDF

Rationale: Antiepileptic drugs (AEDs) have been available for many years; yet, new members of this class continue to be identified and developed due to the limitations of existing drugs, which include a propensity for cognitive impairment. However, there is little preclinical information about the cognitive effects they produce, which clinically include deficits in attention and slowing of reaction time.

Objectives: The purpose of this study was to profile two first-generation AEDs, phenytoin and valproate, and three second-generation AEDs, levetiracetam, pregabalin and lacosamide.

View Article and Find Full Text PDF

Lacosamide ((R)-2-acetamido-N-benzyl-3-methoxypropionamide; formerly harkoseride, SPM 927; Vimpat), has been recently approved by US and European regulatory authorities for use as add-on therapy for partial-onset seizures in adults. Because a number of anti-epileptic drugs are used to treat conditions beyond epilepsy, including anxiety, in the present study we investigated the anxiolytic potential of lacosamide in a conditioned emotional response (CER) model in rat, and the mouse marble burying assay. In each test lacosamide produced a significant effect consistent with anxiolysis, i.

View Article and Find Full Text PDF

Proper mitotic progression is crucial for maintenance of genomic integrity in proliferating cells and is regulated through an intricate series of events, including protein phosphorylation governed by a complex network of protein kinases. One kinase family implicated in the regulation of mitotic progression is protein kinase CK2, a small family of enzymes that is overexpressed in cancer and induces transformation in mice and cultured fibroblasts. CK2alpha, one isoform of the catalytic subunits of CK2, is maximally phosphorylated at four sites in nocodazole-treated cells.

View Article and Find Full Text PDF

Foliar diseases like apple scab result in significant economic losses to growers each year. Assessment in past studies involved only macroscopic disease ratings. More complete knowledge of the fate and behavior of fungicide has been needed to reduce pesticide use with less off-target contamination.

View Article and Find Full Text PDF

Protein kinase CK2 exhibits oncogenic activity in mice and is over-expressed in a number of tumors or leukemic cells. On the basis of its amino acid sequence and a wealth of experimental information, CK2 has traditionally been classified as a protein serine/threonine kinase. In contrast to this traditional view of CK2, recent evidence has shown that CK2 can also phosphorylate tyrosine residues under some circumstances in vitro and in yeast.

View Article and Find Full Text PDF

Background: LQTS may cause sudden cardiac death (SCD), but the mechanisms linking gene mutations to ventricular fibrillation (VF) are unclear.

Objective: To determine whether ventricular activation delays in congenital long QT syndrome (LQTS) are associated with VF and to describe these delays clinically by measuring activation through ventricular myocardium after a premature extrastimulus.

Methods: Forty-six patients with LQTS, including 16 with VF (LQTS VF) were investigated, and the results were compared with those from 24 patients with hypertrophic cardiomyopathy and VF (HCM VF).

View Article and Find Full Text PDF

Aims: A linear lesion between the left inferior pulmonary vein orifice and mitral annulus, the so-called mitral isthmus, may improve the success of catheter ablation for atrial fibrillation. Gaps in the lesion line, however, may facilitate left atrial flutter. The aim of the study was to determine the optimal location of the lesion line by serial sectioning of the isthmus area.

View Article and Find Full Text PDF

Background: The experiences of how patients live with an implantable cardioverter defibrillator are still poorly understood. Only a few qualitative studies have investigated this phenomenon. This paper was undertaken as part of a larger project to evaluate quality of life and psychological well-being in those survivors of cardiac arrest who have received an implantable cardioverter defibrillator.

View Article and Find Full Text PDF

Three sprayers were evaluated for their affect on retention and efficacy: a carbon dioxide powered high-volume sprayer, a DRAMM coldfogger, and an Electrostatic Spraying Systems (ESS) sprayer with air-assistance. The active ingredients used were spinosad and azadirachtin. The plant canopy was constructed in the greenhouse using potted soybeans (Glycine max (L) Merrill cr Pioneer 9392).

View Article and Find Full Text PDF

Current theory governing the biological effectiveness of toxicants stresses the dose-response relationship and focuses on uniform toxicant distributions in the insect's environment. However, toxicants are seldom uniformly dispersed under field conditions. Toxicant distribution affects bioavailability, but the mechanics of such interactions is not well documented.

View Article and Find Full Text PDF

Mechanized production and delivery of biological pesticides presents challenges because the biological agents must remain viable during these processes. This study evaluates the effect of flow through an abrupt contraction, where flow characteristics similar to that found within bioprocesses and spray equipment are developed, on damage to a benchmark biological pest control agent, entomopathogenic nematodes (EPNs). An opposed-pistons, contraction flow device generated volumetric flow rates ranging between 8.

View Article and Find Full Text PDF

Background: The mechanism by which structural barriers promote wave break and fibrillation is unclear. Conduction velocity (CV) restitution is an important determinant of wave break. Abnormal CV restitution is associated with ventricular fibrillation in patients with heart disease and arises preferentially in fibrotic myocardium.

View Article and Find Full Text PDF

Junctional ectopic tachycardia is a relatively rare disorder, frequently refractory to drug therapy, and with a poor prognosis in childhood. This report describes a successful radiofrequency catheter ablation of the focus of this arrhythmia in a 9-year-old girl with preservation of normal atrioventricular conduction, using precise catheter navigation with the LocaLisa system and carefully titrated RF delivery.

View Article and Find Full Text PDF

Background: Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogram duration starts to increase (S1S2delay) are seen both in hypertrophic cardiomyopathy (HCM) in those at risk of VF and in patients with idiopathic VF (IVF).

Methods And Results: DeltaED and S1S2delay have been measured using paced electrogram fractionation analysis in 266 patients with noncoronary heart disease.

View Article and Find Full Text PDF

Background: During a catheter ablation procedure for selective electrical isolation of pulmonary vein (PV) ostia, the size of these ostia is usually estimated using fluoroscopic angiography. This measurement may be misleading, however, because only the projected supero/inferior ostium diameters can be measured. In this study, we analyzed 3-dimensional magnetic resonance angiographic (MRA) images to measure the minimal and maximal cross-sectional diameter of PV ostia in relation to the diameter that would have been projected on fluoroscopic angiograms during a catheter ablation procedure.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session393l7qa00ls03vgea4opuqn35iucus94): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once