Assessment of myocardial function of the systemic right ventricle in patients with D-transposition of the great arteries after atrial switch operation by tissue Doppler echocardiography.

INTRODUCTION: The long-term follow-up of patients with D-transposition of the great arteries after atrial switch operation shows specific problems such as tricuspid valve insufficiency, rhythm disturbances and failure of the morphologic right ventricle in systemic position. Assessment of the myocardial contractility of the subaortic right ventricle by conventional echocardiography is limited. The usage of tissue Doppler echocardiography with strain combined with strain rate imaging provides a new approach for quantitative analysis of longitudinal myocardial function. The aim of this study was to assess patterns of wall motion and regional contractile function of the systemic right ventricle in patients after atrial switch operation for D-transposition of the great arteries and to compare them to those of normal subjects. PATIENTS AND METHODS: Twenty-four patients with Dtransposition of the great arteries after atrial switch operation with a mean age of 21.3 (range, 13 to 31) years and a postoperative period of 16.9 years were examined and compared to 22 control individuals with a mean age of 21.5 (range, 3 to 43) years. Tissue Doppler studies were obtained from apical 4- chamber view to determine regional systolic (Syst(T)) and diastolic (E(T), A(T)) velocities as well as E(T)/A(T) ratio at the basal free wall. The presystolic isovolumic contraction peak was assessed and the ratio of the presystolic peak velocity to the isovolumic acceleration time as the IVA index was calculated. Strain and peak systolic and diastolic strain rates were assessed on basal, middle and apical segments of the right ventricular free wall. Data obtained from the morphologic right systemic ventricle in patients were compared to those derived from the left and the right ventricle in controls. RESULTS: The right ventricular free wall systolic velocities were significantly reduced in patients compared to velocities obtained from the normal right and left ventricle. On the other hand, the IVA index was only reduced in patients compared to the IVA index in the normal subpulmonary right ventricle. Compared to data obtained from the normal systemic left ventricle, the IVA index in patients was not significantly different. In contrast, strain and strain rate parameters in all analyzed segments mostly showed a highly significant reduction compared to normal right and left ventricular data. CONCLUSION: Tissue Doppler echocardiography is a promising tool for the evaluation of regional myocardial contractile function of the morphologic right systemic ventricle in patients following atrial switch operation for D-transposition of the great arteries. Presystolic, systolic and diastolic regional ventricular function was reduced in the systemic right ventricle. However, further comparative studies using other quantitative parameters of global and regional myocardial function derived from cardiac catheterization or MRI should be performed in order to evaluate the reliability of tissue Doppler echocardiography for the assessment of global right ventricular function in these patients.

[Evaluation of abnormal myocardial wall motions in patients with univentricular heart by tissue Doppler echocardiography]. / Evaluation abnormer Myokardwandgeschwindigkeiten des univentrikulären Herzens mittels Gewebedoppler-Echokardiographie.

INTRODUCTION: Assessment of systolic and diastolic ventricular function in children and adults with morphologically and functionally univentricular heart is difficult using the conventional echocardiographic methods. Quantitative assessment of systolic and diastolic wall motion by TDE may provide information on abnormal systolic and diastolic ventricular function. Thus, the object of this study was to analyze the patterns of anterior and posterior wall motions in children with univentricular heart after palliative Fontan operation in comparison to normal subjects. PATIENTS AND METHODS: We investigated 21 patients of an average age of 10.1 years (range 4.2 to 32 years) with the primary diagnosis of univentricular heart and tricuspid atresia after a median period of 4.3 (range 1.2 to 8) years after cavo-pulmonary anastomosis (Fontan procedure) and in comparison to a normal collective of children without cardiovascular malformations. For investigation we used the novel tissue Doppler echocardiography (TDE) (EchoPack 6.3.6, Vingmed, Norway). Thereby we chose the standardized apical view and evaluated the left and right annular systolic (S(T)), early diastolic (E(T)) and atrial (A(T)) motion. We also registered the acceleration and deceleration time of each obtained curve. RESULTS: In comparison to the posterior myocardial wall the velocities at the anterior wall of the rudimentary ventricle were significantly reduced in all patients with tricuspid atresia and univentricular heart (p<0.0001). Particularly the annular systolic and diastolic wall motions of the rudimentary ventricle as well as their deceleration and acceleration time in patients with univentricular hearts differed significantly from those in healthy persons. CONCLUSION: Abnormal myocardial wall motion is detectable in children and adults with univentricular heart after palliative cardiac procedures using tissue Doppler echocardiography. The hemodynamic value of the measured abnormal wall motions, however, need further comparative studies.

Human members of the SCO1 gene family: complementation analysis in yeast and intracellular localization.

Cytochrome c oxidase is a multiprotein complex in the mitochondrial membrane whose biogenesis requires a number of proteins besides the structural subunits. Several yeast proteins as well as a human disease-related protein have been reported which are involved in cytochrome c oxidase assembly. The S. cerevisiae Sco1p protein has been implicated in the transfer of copper to cytochrome c oxidase subunits Cox1p and/or Cox2p. Here we report on the complementation behavior in yeast of two recently identified ScSco1p homologs of chromosome 17 and chromosome 22 from human. When allotropically expressed in yeast, both genes fail to complement the lack of the ScSCO1 gene. However, a chimera of the N-terminal half of ScSco1p and the C-terminal half of the chromosome 17 homolog does substitute for the ScSco1p function. Interestingly, the respective chimera with the human homolog of chromosome 22 is not able to complement. Expression of EGFP fusions in HeLa cells shows that both human ScSco1p homologs are located in the mitochondria of human cells.

Mitochondrial copper metabolism in yeast: mutational analysis of Sco1p involved in the biogenesis of cytochrome c oxidase.

Saccharomyces cerevisiae Sco1p is believed to be involved in the transfer of copper from the carrier Cox17p to the mitochondrial cytochrome c oxidase subunits 1 and 2. We here report on the results of a mutational analysis of Sco1p. The two cysteine residues of a potential metal-binding motif (CxxxC) are essential for protein function as shown by their substitution by alanines. Chimeras consisting of Sco1p and its homolog S. cerevisiae Sco2p restrict the specificity of Sco1p function to the N-terminal half of the protein. A candidate region for conferring specificity on Sco1p is a stretch of hydrophobic amino acids, which act as a membrane anchor. In line with this suggestion is the result that alterations of individual amino acids within this region impair Sco1p function.

Effect of cholecystokinin on self-stimulation behavior in rats.

Experiments were performed to examine the effects of intracerebroventricularly administered cholecystokinin octapeptide sulfate ester (CCK-8-SE) and unsulfated cholecystokinin octapeptide (CCK-8-NS) on electrical self-stimulation behavior elicited from the medial forebrain bundle. CCK-8-SE and CCK-8-NS in 80 pmol doses reduced the response rate of self-stimulation behavior 22-30 min following injection, while 400 pmol doses of these peptides attenuated self-stimulation behavior between 13 and 36 min. It is suggested that CCK-8-SE and CCK-8-NS interact with central rather than peripheral nervous mechanisms.