Novel Donor Splice Site Mutation in the KVLQT1 Gene is Associated with Long QT Syndrome

KVLQT1 Gene Mutation and LQTS. Introduction : Inherited long QT syndrome (LQTS) recently has been associated with mutations in genes coding for potassium ( KVLQTI, KCNEI , and HERG ) or sodium ( SCN5A ) ion channels involved in regulating either sodium inward or potassium outward currents of heart cells, resulting in prolongation of the repolarization period. We describe a new mutation, a-1 donor splice site mutation in a kindred with two affected members (QTc = 0.61 and 0.54 sec).
Methods and Results : Single stranded conformation polymorphism (SSCP) analyses were performed on DNA fragments amplified by polymerase chain reaction from DNA extracted from whole blood. Aberrant conformers were analyzed by DNA sequencing. SSCP analysis of the KVLQTI gene revealed an aberrant conformer in the affected family members. DNA sequencing confirmed the presence of a G→A change in the last nucleotide of codon 344. This mutation does not cause an amino acid change, but a change of the splice site characteristics at the 3'end of exon 6. The mutation may affect, through deficient splicing, the putative sixth transmembrane segment of the K⁺ channel, and this type of mutation has not previously been described in KVLQTI.
Conclusion : The clinical course of LQTS in the affected family members, in whom no deaths occurred despite 20 to 30 syncopes, can he explained by the ability of the cellular machinery to perform partial correct splicing in the mutant allele. This type of mutation may be misinterpreted as a normal variant, since it is a point mutation causing neither an amino acid change nor the introduction of a stop codon.     

Complete Epicardial Resynchronization Device Implantation in a Patient Who Underwent a Replacement of Mitral and Tricuspid Valve

A 71‐year‐old woman with severe nonischemic dilated cardiomyopathy and low ejection fraction with severe mitral regurgitation and tricuspid regurgitation and pulmonary hypertension underwent multiple valve repairs and cardiac resynchronization therapy implantation with epicardial shock leads. (PACE 2013; 36:e56–e58)     

Retraction of a Malfunctioning Cardiac Bioptome from the Heart

A cardiac bioptome with persistent open jaws due to malfunction was removed from the cardiac cavity after the bioptome covering had been peeled off and a fractured wire identified and manipulated.     

Hepatic Changes Produced by 30-Day Administration of a Novel Aminocyclitol Antibiotic, Trospectomycin Sulfate, to Laboratory Animals

Hepatic Changes Produced by 30-Day Administration of a NovelAminocyclitol Antibiotic, Trospectomycin Sulfate, to LaboratoryAnimals. ULRICH, R. G., PETRELLA, D. K., LARSEN, E. R., COX,J. W., CRAMER, C. T., PIPER, R. C, AND GRAY, J. E. (1990). Fundam.Appl. Toxi-col. 14, 60–70. The studies described herewere done to characterize the hepatic response to a new aminocyclitolantibiotic, trospectomycin sulfate, administered intravenously(beagle dog) or subcutaneously (Sprague-Dawley rat) at a varietyof dose levels, to investigate reversibility of observed changes,and to document any untoward effects of subchronic trospectomycinsulfate administration. Both species showed significant elevationsin serum levels of alanine and aspartate transaminases in higherdose groups. In the dog only, a transient neuromuscular blockadewas also observed within higher dose groups. No other functional,morphological, or serum chemical changes were observed. Examinationof liver by electron microscopy revealed the presence of cytoplasmiclamellar inclusion bodies, concentrated in the bile canalicularregion of the hepatocytes. Occurrence of the lamellar bodiesand coincident transaminase increases were found to be reversibleupon discontinuance of treatment (studied in the dog). Electronmicroscopy of acid phosphatase cytochemistry in the rat indicatedthat most, but not all, of the lamellar bodies contained thisenzyme. This observation suggests that they may be derived fromthe lysosome, or once formed become lysosomal.