Hypertrophic cardiomyopathy with preexcitation: insights from noninvasive electrocardiographic imaging (ECGI) and catheter mapping.
Hypertrophic Cardiomyopathy and Preexcitation.



Fasciculoventricular pathway has been described as an unusual variant of preexcitation. Electrocardiographic imaging (ECGI) is a novel imaging modality for noninvasive electroanatomic mapping of epicardial activation and repolarization.



We present a case of an 18-year-old male with hypertrophic cardiomyopathy (HCM) and an electrocardiogram (ECG)-based diagnosis of Wolff-Parkinson-White (WPW) syndrome, who underwent a noninvasive ECGI study to image ventricular activation, followed by an electrophysiology study (EPS). The ECGI electroanatomic isochrone map showed early activation of the epicardial aspect of the atrioventricular (A-V) groove and an aberrant posterior-base-to-apex progression of activation in the left ventricular (LV) epicardium. The EPS showed a likely fasciculoventricular pathway (FVP) without any inducible tachycardia.



While FVP has been described before, this is the first report of detailed quantitative three-dimensional characterization of electrical activation sequence of a heart with this type of preexcitation, using a novel noninvasive imaging modality (ECGI). In spite of abnormal ventricular activation, the EPS demonstrated that the FVP is not capable of supporting reentrant supraventricular tachycardia or rapidly conducted atrial fibrillation.

title: Cardiac memory in patients with Wolff-Parkinson-White syndrome: noninvasive imaging of activation and repolarization before and after catheter ablation.
abstract: Cardiac memory refers to a change in ventricular repolarization induced by and persisting for minutes to months after cessation of a period of altered ventricular activation (eg, resulting from pacing or preexcitation in patients with Wolff-Parkinson-White syndrome). ECG imaging (ECGI) is a novel imaging modality for noninvasive electroanatomic mapping of epicardial activation and repolarization.



Fourteen pediatric patients with Wolff-Parkinson-White syndrome and no other congenital disease, were imaged with ECGI a day before and 45 minutes, 1 week, and 1 month after successful catheter ablation. ECGI determined that preexcitation sites were consistent with sites of successful ablation in all cases to within a 1-hour arc of each atrioventricular annulus. In the preexcited rhythm, activation-recovery interval (ARI) was the longest (349+/-6 ms) in the area of preexcitation leading to high average base-to-apex ARI dispersion of 95+/-9 ms (normal is approximately 40 ms). The ARI dispersion remained the same 45 minutes after ablation, although the activation sequence was restored to normal. ARI dispersion was still high (79+/-9 ms) 1 week later and returned to normal (45+/-6 ms) 1 month after ablation.



The study demonstrates that ECGI can noninvasively localize ventricular insertion sites of accessory pathways to guide ablation and evaluate its outcome in pediatric patients with Wolff-Parkinson-White syndrome. Wolff-Parkinson-White is associated with high ARI dispersion in the preexcited rhythm that persists after ablation and gradually returns to normal over a period of 1 month, demonstrating the presence of cardiac memory. The 1-month time course is consistent with transcriptional reprogramming and remodeling of ion channels.

title: Volatilization of Mercury by Resting Mercury-Resistant Bacterial Cells

abstract: The mercuric ion reduction system encoded by the Hg2+ inducible mer operon confers bacterial resistance to mercuric ion. The mer A gene product which is a FAD-containing enzyme catalyzes the reduction of Hg2+ to volatile elemental mercury with the help of intracellular thiols and NADPH as a cofactor (Schottel 1974; Summers and Silver 1978; Fox and Walsh 1982; Misra 1992). Our earlier studies have shown that growing cells of different mercury-resistant bacteria reduce Hg2+ compounds to Hg(O) (Ray et al. 1989; Pahan et al. 1990a; Gachhui et al. 1989). We have also shown the effect of thiol compounds and flavins on mercury-degrading enzyme activities in mercury-resistant bacteria (Pahan et al. 1990b). Here we report that resting cells of mercury-resistant bacteria survive in a buffer system for several hours, synthesize inducible mercury-degrading enzymes and volatilize mercury from a mercury-containing buffer system. We know of no information regarding studies of mercury-degrading enzymes in resting mercury-resistant bacterial cells.

title: Molecular characterization of a porcine Group A rotavirus strain with G12 genotype specificity
abstract: A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%–95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.

title: A fluorescence correlation spectroscopy study of the diffusion of an organic dye in the gel phase and fluid phase of a single lipid vesicle.
abstract: The mobility of the organic dye DCM (4-dicyanomethylene-2-methyl-6-p-dimethyl aminostyryl-4H-pyran) in the gel and fluid phases of a lipid vesicle is studied by fluorescence correlation spectroscopy (FCS). Using FCS, translational diffusion of DCM is determined in the gel phase and fluid phase of a single lipid vesicle adhered to a glass surface. The size of a lipid vesicle (average diameter approximately 100 nm) is smaller than the diffraction limited spot size (approximately 250 nm) of the microscope. Thus, the vesicle is confined within the laser focus. Three lipid vesicles (1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)) having different gel transition temperatures (-1, 23, and 41 degrees C, respectively) were studied. The diffusion coefficient of the dye DCM in bulk water is approximately 300 microm(2)/s. In the lipid vesicle, the average D(t) decreases markedly to approximately 5 microm(2)/s (approximately 60 times) in the gel phase (for DPPC at 20 degrees C) and 40 microm(2)/s ( approximately 8 times) in the fluid phase (for DLPC at 20 degrees C). This clearly demonstrates higher mobility in the fluid phase compared with the gel phase of a lipid. It is observed that the D(t) values vary from lipid to lipid and there is a distribution of D(t) values. The diffusion of the hydrophobic dye DCM (D(t) approximately 5 microm(2)/s) in the DPPC vesicle is found to be 8 times smaller than that of a hydrophilic anioinic dye C343 (D(t) approximately 40 microm(2)/s). This is attributed to different locations of the hydrophobic (DCM) and hydrophilic (C343) dyes.

title: A novel non-parametric regression reveals linkage on chromosome 4 for the number of externalizing symptoms in sib-pairs.
abstract: In this report, we present results of a genome-wide linkage scan using as a phenotype the number of externalizing symptoms associated with alcohol use disorders. Subjects were collected by the Collaborative Study on the Genetics of Alcoholism project from families in which at least three first degree relatives were affected by alcohol dependence. We use a novel non-parametric regression method based on kernel smoothing for our analysis. We report a statistically significant linkage close to the ADH gene cluster on Chromosome 4. We also obtain evidence for epistatic interaction between a region on Chromosome 1 and one on Chromosome 15. Although alcoholism as a covariate does not have any effect on the linkage scan, it has an effect on the epistatic interaction.

title: Idiopathic intracranial hypertension in a child after hemodialysis.
abstract: Idiopathic intracranial hypertension remains a disease of unknown etiology. Epidemiology, associations, features, and prognosis in children have changed over the years. The main clinical complaint of pediatric idiopathic intracranial hypertension is headache with visual disturbance. We report on a patient with childhood idiopathic intracranial hypertension, who presented without headache after hemodialysis for acute renal failure. Idiopathic intracranial hypertension without headache is believed to have a poor prognosis. However, this child demonstrated a favorable outcome with medical therapy. The child was followed with serial optical coherence tomography of retinal nerve fiber layer thickness around the optic nerve head. In the absence of a reliable procedure to evaluate the therapeutic efficacy in the follow-up of patients with idiopathic intracranial hypertension, the importance of optical coherence tomography, a noninvasive, objective, and reproducible procedure, is highlighted as a useful adjunct in the management of idiopathic intracranial hypertension.