Long QT syndrome and life threatening arrhythmia in a newborn: molecular diagnosis and treatment response.

Intrauterine and neonatal manifestations of congenital long QT syndrome are associated with a high cardiac risk, particularly when atrioventricular block and excessive QT prolongation (> 600 ms(1/2)) are present. In a female newborn with these features, treatment with propranolol and mexiletine led to complete reduction of arrhythmia that was maintained 1.5 years later.

[Long QT-syndromes: diagnosis and genetics].

The long-QT syndrome (LQTS) is a familiar disease characterized by abnormal myocardial repolarization and a high risk of sudden cardiac death. As a hallmark of the disease, the heart-rate corrected QT interval is intrinsically prolonged. Recent advances in molecular genetics have elicited that various inborn defects in cardiac ion channel genes regulating cardiac ion currents underlie this propensity to develop malignant ventricular arrhythmias.

Cytoplasmic retention of mutant tsp53 is dependent on an intermediate filament protein (vimentin) scaffold.

The temperature-sensitive mutant tsp53val135 accumulates in the cytoplasm of cells kept at the non-permissive temperature (39 degrees C), but is rapidly transported into the cell nucleus at the permissive temperature (30 degrees C). tsp53 thus may serve as a model for analysing cellular parameters influencing the subcellular location of p53. Here we provide evidence that retention of tsp53 in the cytoplasm at the non-permissive temperature is due to cytoskeletal anchorage of the p53 protein.

Cytoskeleton architecture of C6 rat glioma cell subclones whole mount electron microscopy and immunogold labeling.

Whole mount electron microscopy of extracted cells combined with immunogold labeling techniques can be used to characterize the cytoskeletal architecture of cultured cells. As shown with subclones of the C6 rat glioma cell line, heavy metal shadowing was suitable for getting basic information concerning the arrangement of the various filament types within the networks. Pure carbon shadowing combined with immunogold double labeling proved to be optimal to identify linkages between filaments, to localize filament associated proteins and to follow the arrangement of filaments in dense arrays such as lamellipodiae and cell margins.