bluuebunny/crossref_metadata_2025_split huggingface dataset:
VICKZ proteins: a multi‐talented family of regulatory RNA‐binding proteins
Authors: Yisraeli Joel K. 
Published: January 2005

AbstractThe highly conserved VICKZ (Vg1 RBP/Vera, IMP‐1,2,3, CRD‐BP, KOC, ZBP‐1) family of RNA‐binding proteins recognize specific cis‐acting elements in a variety of different RNAs and have been implicated in cell polarity and migration, cell proliferation, and cancer. In just the last two years, the use of transgenic mice, antisense RNA, and RNAi (RNA interference) techniques have contributed to our understanding of the roles of these proteins and how they interface with many diverse processes in cells. In this article, I will review the recent advances relating to VICKZ proteins and try to suggest a framework for understanding how, in conjunction with other RNA‐binding proteins, they participate in a combinatorial fashion to help determine the fate of their RNA targets and, ultimately, the function of cells in which they are expressed. Such a ‘post‐transcriptional operon’ model, as proposed by Keene and Tenenbaum [(2002) Mol. Cell 9, 1161‐1167], can explain the differential, integrated action of multiple RNA‐binding proteins on mRNA targets.
Atrioventricular Junction Ablation and Pacemaker Therapy in Patients with Drug‐Resistant Atrial Tachyarrhythmias after the Fontan Operation
Authors: FRIEDMAN RICHARD A. , WILL JOACHIM C. , FENRICH ARNOLD L. , KERTESZ NAOMI J. 
Published: January 2005

Introduction: Drug‐resistant intraatrial reentrant tachycardia (IART) occurs frequently after the Fontan operation and is a major cause of morbidity and rarely mortality. We describe our experience with AV junction ablation after pacemaker implantation in postoperative Fontan patients with drug‐resistant IART. Methods and Results: We performed retrospective analysis of Fontan patients with IART and attempted radiofrequency ablation (RFA) of the AV junction. Seven patients (6 male) were identified, with a mean age at Fontan of 9.3 years (range 5.8–13.3) and a median age at RFA of 18 years (range 14.5–23.3). Mean follow‐up prior to RFA was 764 ± 235 days and after RFA 1,541 ± 1,235 days. IART was refractory to antiarrhythmic drugs in all patients, and all had undergone pacemaker placement. Mean onset of IART was 44.1 months (range 0–142) after Fontan. Mean duration of atrial arrhythmia prior to RFA was 72 ± 48 m (range 16–148). Ablation of the AV junction was successful or partially successful in all patients. Complete AV block occurred in 6 patients. Normal AV conduction was not seen during a mean follow‐up of 1,541 days. The mean number of antiarrhythmic medications decreased from 2.8 ± 1.5 to 0.7 ± 0.8 (P < 0.05). Conclusion: In Fontan patients with drug‐resistant IART, RFA of the AV junction with prior pacemaker implant is an effective therapeutic option. Despite the introduction of pacemaker dependence, this option should be considered in patients who did not respond to RFA of IART or who are at high operative risk for Fontan conversion.
QT Correction Methods in Children and Adolescents
Authors: WERNICKE JOACHIM F. , FARIES DOUGLAS , BREITUNG REBECCA , GIROD DONALD 
Published: January 2005

Introduction: Accurate determination of the QTc interval has become increasingly important in the assessment of a drug's ability to prolong cardiac repolarization. Previous work suggests the most appropriate correction formula for adults is QTc = QT/RR0.40, but little on correction methods for children and adolescents has been published. Methods and Results: In this study, ECG data were obtained from a meta‐analysis of seven clinical trials for attention deficit/hyperactivity disorder (ADHD) involving 2,288 children and adolescents. The most appropriate formula for children and adolescents included in this database was found to be QTc = QT/RR0.38. Adjustments of the correction factor specifically for males and females of different ages also are reported. Conclusion: QT correction methods developed for adults do not apply to children. As accurate QTc determination plays a larger role in assessing a drug's potential to retard repolarization, use of age‐ and gender‐specific correction formulas becomes more important.
Hypertension and Hypertensive Heart Disease Are Associated with Increased Ostial Pulmonary Vein Diameter
Authors: HERWEG BENGT , SICHROVSKY TINA , POLOSAJIAN LEO , ROZENSHTEIN ANNA , STEINBERG JONATHAN S. 
Published: January 2005

Introduction: Atrial fibrillation (AF) is associated with increased ostial pulmonary vein (PV) diameter and commonly with hypertension. We sought to investigate ostial PV anatomy in patients with and without AF with the goal of characterizing the relationship to hypertension and cardiovascular disease. Methods and Results: Ostial PV diameter was assessed by preprocedural spiral computed tomography in 100 AF patients undergoing a PV isolation procedure and in 24 age‐ and sex‐matched non‐AF control patients. Ostial diameter of 392 PVs in 100 AF patients was increased compared to 106 PVs in 24 non‐AF controls (1.50 ± 0.31 vs 1.20 ± 0.31 cm, P < 0.001) and diameters of individual PVs were uniformly affected (r = 0.45–0.62, P < 0.001). Left atrial dilation was associated with a larger PV diameter (1.56 ± 0.32 vs 1.44 ± 0.29 cm, P < 0.01). PV diameter in AF patients with hypertension (1.55 ± 0.32 cm), particularly if associated with left ventricular hypertrophy (1.66 ± 0.37 cm), was larger compared to AF patients without hypertension (1.43 ± 0.26 cm, P < 0.01). PV diameter in control patients with hypertension (n = 14) was larger than in those without hypertension (n = 10, P < 0.01). Patients with persistent AF had larger PV diameters (1.61 ± 0.34 cm) than patients with paroxysmal AF (1.47 ± 0.30 cm, P < 0.01). Male gender (P < 0.01), history of hypertension (P < 0.01), and persistent AF (P < 0.05) were identified as independent cofactors of increased ostial PV diameter. Conclusion: PV dilation affects all PVs uniformly in AF patients. Hypertension and hypertensive heart disease in patients with and without AF are associated with PV dilation, supporting theories that impaired left ventricular diastolic function is associated with a stretch‐induced PV arrhythmia mechanism.
Assessment of Markers for Identifying Patients at Risk for Life‐Threatening Arrhythmic Events in Brugada Syndrome
Authors: AJIRO YOUICHI , HAGIWARA NOBUHISA , KASANUKI HIROSHI 
Published: January 2005

Introduction: Risk stratification for life‐threatening arrhythmic events in Brugada syndrome is not yet established. The aim of the present study was to examine the usefulness of various markers in predicting life‐threatening arrhythmic events in the Brugada syndrome. Methods and Results: Forty‐six patients with Brugada‐type ECGs were categorized into the symptomatic (n = 28) and asymptomatic (n = 18) groups. Statistical analyses were performed with respect to the usefulness of the following markers: SCN5A mutation, pharmacologic challenge, ventricular fibrillation (VF) inducibility by programmed electrical stimulation, and late potential (LP) by signal‐averaged ECG (SAECG). Comparison between the two groups revealed a significant difference only in LP positivity (92.6% vs 47.1%, P = 0.0004). The symptomatic group had significantly lower RMS40, longer LAS40, and longer fQRSd compared with the asymptomatic group. A significant difference was noted, especially RMS40. The positive predictive value, negative predictive value, and predictive accuracy when setting a cutoff value of 15 μV were 92.0%, 78.9%, and 86.4%, respectively. Furthermore, patients with an RMS40 value <15 μV (n = 25) showed significantly higher rates of VF recurrence compared with patients with an RMS40 value ≥ 15 μV (n = 19, P = 0.047). Conclusion: Regarding risk stratification for identifying high‐risk patients in Brugada syndrome, only LP by SAECG was shown to be useful, suggesting the importance of RMS40 in predicting the history of life‐threatening arrhythmic events and the recurrence of VF.
Absence of Msx2 Does Not Affect Cardiac Conduction or Rescue Conduction Defects Associated with Nkx2‐5 Mutation
Authors: JAY PATRICK Y. , MAGUIRE COLIN T. , WAKIMOTO HIROKO , IZUMO SEIGO , BERUL CHARLES I. 
Published: January 2005

Introduction: The transcription factors governing embryonic development of the AV conduction system are largely unknown. Heterozygous mutations of the cardiac transcription factor Nkx2‐5 cause AV conduction defects, which are associated with anatomic hypoplasia of the conduction system. In situ expression patterns of Msx2 in the mouse and chick embryonic heart have suggested a developmental function for this transcription factor. Homozygous Nkx2‐5 knockout mouse embryos express Msx2 ectopically throughout the myocardium, suggesting Msx2 affects conduction system development through a transcriptional cascade starting with Nkx2‐5. Several observations support a model in which Msx2 negatively regulates formation of the conduction system and inappropriate Msx2 up‐regulation causes the conduction defects associated with Nkx2‐5 mutation. Methods and Results: We obtained surface ECGs and performed intracardiac electrophysiologic studies in Msx2 knockout mice and in Nkx2‐5 wild‐type and heterozygous null mutant mice in an Msx2 null mutant background. Msx2 null mutant mice had normal cardiac conduction and no increased vulnerability to inducible arrhythmia. Absence of Msx2 did not alter the conduction defects observed in heterozygous Nkx2‐5 knockout mice. Conclusion: Msx2 likely does not contribute to development of the conduction system. Abnormal Msx2 expression likely does not cause the AV conduction defects present in Nkx2‐5 knockout mice.
Morphologic Remodeling of Pulmonary Veins and Left Atrium after Catheter Ablation of Atrial Fibrillation:
Authors: TSAO HSUAN‐MING , WU MEI‐HAN , HUANG BIEN‐HSIEN , LEE SHIH‐HUANG , LEE KUN‐TAI , TAI CHING‐TAI , LIN YUNG‐KUO , HSIEH MING‐HSIUNG , KUO JEN‐YUAN , LEI MENG‐HUAN , CHEN SHIH‐ANN 
Published: January 2005

Introduction: Understanding the structural remodeling and reverse remodeling of the left atrium (LA) and pulmonary vein (PV) after radiofrequency ablation of atrial fibrillation (AF) may provide important insights into the mechanism and management of AF. This study used magnetic resonance angiographic (MRA) images to investigate changes in PV and LA morphologies before and more than 1 year after ablation. Method and Results: Forty‐five patients (36 men and 9 women, mean age 60 ± 13 years) who underwent MRA before and more than 12 months (mean 21 ± 11) after ablation of paroxysmal AF were included in the study. The patients were divided into two groups: group I included 35 patients without AF recurrence, and group II included 10 patients with late (>1 month postablation) recurrence of AF. The sizes of the LA and nonablated PV were compared before and after ablation. In group I, significant reduction of ostial area of both superior PVs was noted (left superior PV: from 2.85 ± 0.67 to 2.59 ± 0.73 cm2; right superior PV: from 2.89 ± 0.85 to 2.60 ± 0.73 cm2, both P < 0.001). Geometric alteration toward a round shape was noted in the ostia of superior PVs during follow‐up (eccentricity of right superior PV and left superior PV decreased from 0.31 ± 0.10 to 0.22 ± 0.13 and from 0.27 ± 0.11 to 0.19 ± 0.13, respectively, oth P < 0.01). However, LA volume showed only borderline reduction (from 61.52 ± 19.06 to 56.64 ± 17.13 mL, P = 0.05). In group II, significant dilation of the LA (from 61.14 ± 17.54 to 78.73 ± 25.27 mL, P = 0.004) and right superior PV (from 3.41 ± 1.12 to 4.08 ± 1.31 cm2, P = 0.016) was noted during follow‐up. Ostial area and eccentricity of the left superior, left inferior, and right inferior PVs and LA were similar before and after ablation. Conclusion: Structural remodeling of the superior PVs and LA can be reversible after successful ablation without AF recurrence; however, late recurrence of AF is associated with progressive LA dilation.
Impaired Baroreflex Gain in Patients with Inappropriate Sinus Tachycardia
Authors: LEON HERNANDO , GUZMAN JUAN CAMILO , KUUSELA TOM , DILLENBURG REJANE , KAMATH MARK , MORILLO CARLOS A. 
Published: January 2005

Introduction: The aim of this study was to determine the characteristics of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex gain (BRG) at rest and during orthostatic stress in patients with clinical criteria of inappropriate sinus tachycardia (IST). Methods and Results: Beat‐to‐beat HRV and BPV, measured by time‐ and frequency‐domain methods, and noninvasive BRG, calculated by cross‐spectral analysis, were obtained during 10 minutes both at rest and during the stabilization phase (5–15 min) of orthostatic stress at 60° in 8 patients with clinical criteria of IST and 9 healthy volunteers (CON). IST patients had a higher resting mean heart rate (78.8 ± 5.3 vs 58.5 ± 4.2 beats/min, P = 0.01) and mean blood pressure (90.4 ± 2.4 vs 72.0 ± 4.2 mmHg; P = 0.002). RMSSD, pNN50m, and BRG were significantly reduced in IST patients at rest. BRG during orthostatic stress (7.2 ± 0.8 vs 20.3 (2.4 ms/mmHg, P < 0.01) was significantly reduced in IST patients. Δ BRG (−16.9%± 11 vs −50.1%± 5, P = 0.02) was markedly blunted during orthostatic stress in IST patients. Conclusion: BRG was markedly impaired both at rest and during orthostatic stress in IST patients. This alteration may be responsible for the higher resting heart rate and mean blood pressures seen at rest and may facilitate tachycardia during orthostatic stress. A primary alteration in sinus node automaticity coupled with impaired BRG determines heart rate response to orthostatic stress in patients with IST.
Further Insights into the Effect of Quinidine in Short QT Syndrome Caused by a Mutation in HERG
Authors: WOLPERT CHRISTIAN , SCHIMPF RAINER , GIUSTETTO CARLA , ANTZELEVITCH CHARLES , CORDEIRO JONATHAN , DUMAINE ROBERT , BRUGADA RAMON , HONG KUI , BAUERSFELD URS , GAITA FIORENZO , BORGGREFE MARTIN 
Published: January 2005

Introduction: The principal aim of this study was to assess the efficacy of quinidine in suppressing IKr in vitro and in modulating the rate dependence of the QT interval in the “SQT1” form of the short QT syndrome. Methods and Results: Graded‐intensity bicycle exercise testing was performed off drug in three patients and during oral quinidine in two patients with short QT syndrome and compared to a control group of healthy normal subjects. The in vitro effects of quinidine on currents in patch clamp technique were investigated. Off drugs QTpV3/heart rate correlation is much weaker in patients with short QT syndrome, and QTpV3 shortens less with heart rate increase compared to normal subjects. In addition to prolonging the QT interval into the normal range, quinidine restored the heart rate dependence of the QT interval toward a range of adaptation reported for normal subjects. Data from heterologous expression of wild‐type and mutant HERG genes indicate the mutation causes a 20‐fold increase in IC50 of d‐sotalol but only a 5.8‐fold increase in IC50 of quinidine. Conclusion: Oral quinidine is effective in suppressing the gain of function in IKr responsible for some cases of short QT syndrome with a mutation in HERG and thus restoring normal rate dependence of the QT interval and rendering ventricular tachycardia/ventricular fibrillation noninducible.
Utility of Routine Follow‐Up Defibrillator Threshold Testing in Congenital Heart Disease and Pediatric Populations
Authors: STEPHENSON ELIZABETH A. , CECCHIN FRANK , WALSH EDWARD P. , BERUL CHARLES I. 
Published: January 2005

Introduction: Recent studies have suggested that routine defibrillation threshold (DFT) testing of implantable cardioverter defibrillators (ICDs) in adults may not be necessary. The congenital heart disease and pediatric populations are a unique group of ICD recipients having a higher incidence of lead failure. We investigated the utility of follow‐up DFT testing in this population. Methods and Results: The records of 155 ICD recipients at one center were retrospectively reviewed, and patients having one or more follow‐up DFT tests were analyzed. The patients were divided into two groups. The “routine” group consisted of 58 follow‐up DFT procedures in 46 patients, without known changes in ICD parameters. The “prompted” group consisted of 21 follow‐up DFT procedures in 18 patients, motivated by clinical concerns about changes in ICD lead status. Of 58 “routine” DFTs performed at a mean postimplant duration of 32 ± 23 months (range 2–78), 7 (12%) had reprogramming, and 1 required a hardware change as a result of the testing. Of the 21 “prompted” DFTs performed, 7 required device reprogramming, and 3 required hardware upgrade. Overall, 19 (24%) of 79 procedures detected clinically significant changes, requiring reprogramming or ICD system revision. No complications were seen from follow‐up DFT testing. Conclusion: A high rate of abnormalities was found at follow‐up DFT testing in this population, especially in the group of patients with clinically prompted testing. Clinically indicated DFT testing, as expected, has a high yield of important information on device function in congenital heart disease and pediatric populations.
An Apparatus for the Observation of the Kerr Effect with Microsecond Electrical Pulses
Authors: Kaye Wilbur , Devaney Richard 
Published: January 2005

An apparatus for the observation of the Kerr electro-optic effect in liquids and polymers using microsecond electrical pulses, is presented and evaluated. This method offers a convenient way of studying internal motions and molecular configurations of polymeric material with a minimum of heating usually accompanying these observations. Electrical pulses of from 1- to 1000-microsecond width, 60–1000 p.p.s., at amplitudes up to 5000 volts are generated by conventional methods. These pulses are used to orient low molecular weight and polymeric materials placed between the plates of a condenser. The circular polarization induced in the polarized light passing between the plates actuates a photo-multiplier tube in order that the light pulses may be studied with an oscillograph.
Curves of Kerr constant versus temperature at temperatures to −80°C are compared with the literature. Oscillograms showing the response of several liquids and polymers are shown. Oscillograms showing an interesting difference between orientation and relaxation time are presented, as are oscillograms showing clearly both orientation and distortion polarization simultaneously.
Equations for the Inductances of Three-Phase Coaxial Busses Comprised of Square Tubular Conductors
Authors: Higgins Thomas James , Messinger Henry Peter 
Published: January 2005

Equations are derived for calculating the associated inductances of the conductors of three-phase coaxial busses comprised of square tubular conductors. It is assumed that the conductors are nonmagnetic, are of such lengths that end effects are negligible, are right-cornered, and carry currents uniformly distributed over their cross sections. The general equations are obtained through use of geometric mean distance theory. Approximate equations, the conductors being considered as indefinitely thin, are epitomized in a table which yields values sufficiently accurate for most design work. In turn, these approximate equations are reduced to simple equations which also yield values sufficiently accurate for much design work. These equations for inductance lead to corresponding equations for the reactive voltage drops. Use of these various equations and the relative accuracy to be expected of them is illustrated by calculating the inductances and reactive voltage drops of typical busses.
The changes in the inductances due to rounding the edges of the conductors and the changes produced in both the inductances and the resistances by skin and proximity effects are investigated. The changes in the inductances due to rounding the edges can be approximated by use of a known equation. The changes in the inductances due to power frequency skin and proximity effects prove to be negligible; the changes in the resistances can be calculated by use of known skin-effect factors and newly derived proximity-effect factors.
Calculation of the inductances of three-phase coaxial busses constructed of tubular conductors made up of two channels or angles placed flange to flange is discussed. Finally, attention is called to a relatively little known means of obtaining balanced three-phase operation of geometrically unbalanced three-phase busses.
The Electrostatic Field of a Point Charge Inside a Cylinder, in Connection with Wave Guide Theory
Authors: Bouwkamp C. J. , De Bruijn N. G. 
Published: January 2005

In this paper the field of a point charge inside a hollow, infinitely long circular cylinder is studied. The case of an axial point charge is treated in detail. Three different methods are developed. The first method shows how to calculate the induced charges at the surface of the cylinder without explicit knowledge of the potential itself. The surface charge-density function is obtained as the solution of a Fourier-type integral equation. Then the potential caused by these charges is calculated. The second method works in the opposite direction. Here the potential is obtained as solution of a boundary value problem, followed by the calculation of the corresponding charges at the surface of the cylinder.The integral, obtained for the surface charge density, is transformed by contour integration. Although the resulting series is very useful for numerical purposes, a stronger method is necessary, in order to calculate the charge density just opposite the point source. Figure 1 shows the calculated values of the induced surface charge density. Several approximations for the charge-density function are considered, in connection with recent work of Weber (cf. Table I).The same is done for the field inside the cylinder. Various formulas are given which allow of numerical calculations. In Table II some calculated values of the potential are shown.The third method is based on the theory of Fourier-Bessel-Dini series. The potential is developed in terms of discrete normal solutions of the potential equation in cylindrical coordinates. The coefficients in this development can be derived from the behavior of the potential in the immediate neighborhood of the primary source.Furthermore, it is emphasized that the study of the above potential problem can serve as a guide in questions of wave propagation in hollow circular cylinders. In this connection the third method is shown to be extremely useful, as it enables us to calculate directly the fields in the far zone from that in the immediate neighborhood of the exciting source. This new method is demonstrated in case of acoustic waves inside a cylinder, caused by a harmonically vibrating point source.
Electron Diffraction Study of Particle Size in Thin Bi Films Deposited by Evaporation in Vacuum
Authors: Keogh C. T. , Weber A. H. 
Published: January 2005

Electron diffraction patterns of thin Bi films were studied by the method of microphotometer density curve analysis to determine changes of the film structure with aging and with increase in thickness of the films. All Bi films were deposited on Formvar by evaporation in vacuum. Analysis of the Bi diffraction patterns by comparison with the Formvar pattern as a reference standard indicate that the very thin films (about 20 atom layers or less in thickness) while initially composed of small crystals grow rapidly upon aging into larger crystals. The very thinnest film (about 5 atom layers thick) analyzed exhibited an initial increase in particle size followed by a decrease upon aging, a somewhat anomalous result requiring further confirmation.
Increase in particle size with increase in thickness of the Bi films is observed also, although the results of these latter experiments are somewhat irregular.