Multivariate autoregressive analysis of carotid artery blood flow waveform in an infant of a diabetic mother with cardiomyopathy

We analyzed the carotid artery blood flow waveform (CABFW) of an infant of a non-insulin dependent diabetic mother with hypertrophic cardiomyopathy (IDM cardiomyopathy) through multivariate autoregressive analysis and compared the developmental change of his CABFW with that of normal newborns. The total power was lower than normal newborns on the second and third day of life when his heart dysfunction was severe, and elevated on the fifth day of life when normal-heart function was recovered. The power of component 3 (C3), of which the damping frequency was 7–11 Hz, was slightly high on the second and third day of life and it decreased to the normal range on the fifth day of life by component analysis. In contrast, the power of C3 increased with decreasing resistance index of anterior cerebral artery (RI of ACA) which shows the cerebral vascular resistance of normal newborns. These results suggest that the carotid artery blood flow volume decreased by low cardiac output and the cerebral vascular resistance decreased to maintain the cerebral circulation, when the heart dysfunction was severe.     

Epicardial Macro-Reentrant Ventricular Tachycardia Exhibiting an Endocardial Centrifugal Activation Pattern in a Case with Arrhythmogenic Right Ventricular Cardiomyopathy

A 55-year-old man with arrhythmogenic right ventricular cardiomyopathy underwent catheter ablation of ventricular tachycardia (VT) with left bundle branch block and left superior axis QRS morphology with an early precordial transition. Endocardial mapping during the VT revealed a focal activation pattern from a small region of low voltage in the left ventricular (LV) septum. Despite earliest endocardial activation in the LV septum, epicardial mapping demonstrated a macro-reentrant circuit with successful catheter ablation at an inferior peritricuspid annular site. Activation from the reentrant circuit propagated through the scar area in the epicardial right ventricle to the remote endocardial LV breakout site.     

In Vitro Degradation of Serum Amyloid A by Cathepsin D and Other Acid Proteases: Possible Protection Against Amyloid Fibril Formation

The effects of acid proteases on degradation of serum amyloid A protein (SAA) were investigated in vitro . Human recombinant SAA1 (rSAA1), when incubated with human spleen extracts at pH 3.2, was degraded in the amino-terminal portion of the molecule. This reaction was inhibited by an acid protease inhibitor, pepstatin. The degraded SAA molecules lacking nine or more amino-terminal residues, when exposed to in vitro fibril-forming conditions, failed to form Congo red positive precipitates and did not show amyloid fibril-like structure by electron microscopy. This suggests that the amino-terminal portion of SAA is essential for fibril formation. Cathepsin D, one of the lysosomal enzymes, also initiated degradation of rSAAl at the amino-terminus. Cathepsin D immunoreactivity was detected in marginal areas of amyloid deposits in spleens from patients with reactive amyloidosis. These findings suggest that cathepsin D or similar acid proteases may be involved in SAA catabolism and may protect against amyloid formation.