Coronary vascular reserve and regional myocardial contractile force with special reference to myocardial metabolism

The relations among coronary vascular reserve, regional myocardial contractile force and myocardial metabolism were investigated in anesthetized dogs under open-chest condition. The reactive hyperemia response was examined during stepwise occlusion of circumflex artery. A change in percent repayment was used as an index of the coronary vascular reserve. Contractile force was measured with strain gauge arches sutured to ischemic and nonischemic areas of the left ventricle. The nonischemic muscle contractile force (NIMCF) increased or showed no significant change with the reduction of repayment by stepwise constriction of circumflex artery. The ischemic muscle contractile force (IMCF) began to decrease markedly following reduction of repayment below 50%. NIMCF was found to be slightly decreased by the severe reduction of coronary blood flow (CBF) in ischemic region. Thus there was a low (r = 0.39) correlation between NIMCF and CBF in ischemic region. However, the correlation between IMCF and CBF in ischemic region was relatively high (r = 0.68). The arterial and coronary sinus blood samples were obtained for the determination of oxygen content, lactate and potassium concentrations. In the range of constriction without reduction of CBF, IMCF decreased significantly following reduction of repayment below 50%, but O2, lactate and potassium extraction ratios were not significantly different. Application of further constriction revealed significant reductions of CBF, stroke volume, aortic pressure, IMCF and lactate extraction ratios, and it also revealed significant elevation of O2 extraction ratio. The above observation suggests that a reduction of coronary vascular reserve might affect regional contractile force without change in CBF, and reduction of CBF could decrease regional and global left ventricular performance with changes in myocardial metabolism.

Gaucher-like cells in juvenile GM1-gangliosidosis and in beta-thalassemia -- A histochemical and ultrastructural observation

Peculiar storage cells appearing in bone marrow aspirates from a patient with juvenile GM1-gangliosidosis and from one with beta-thalassemia were examined light microscopically, histochemically and electron microscopically. Light microscopically, most of the storage cells closely resembled Gaucher cells pathognomonic for Gaucher's disease. The cytoplasm of the Gaucher-like cells contained numerous variable-shaped membrane-bound inclusions mostly arranged in a mosaic pattern and filled with fibrillar materials. Intermingled tubular structures were usually narrow as compared to those of the Gaucher cells. These ultrastructural differences of the stored materials between the Gaucher-like cells and Gaucher cells were more clearly substantiated by the high resolution electron microscopy with negative staining technique. Enzyme cytochemically, acid phosphatase activity was proved in or around the storage inclusions, suggesting their lysosomal origin. Histochemically, it might be suggested that the stored materials of the Gaucher-like cells in juvenile GMI-gangliosidosis were non-sulfated acid mucopolysaccharides and glycopeptides, whereas glycoproteins were the major component of the storage cells in beta-thalassemia. Possible mechanisms of storage in the Gaucher-like cells were discussed in both disorders.

Filtration effect of endothelial fenestrations on chylomicron transport in neonatal rat liver sinusoids

The function of endothelial fenestrations in the control of the passage of chylomicrons from the blood to the liver parenchymal cells was studied ultrastructurally in neonatal rats. Measurement of circulating chylomicrons and endothelial fenestrations as well as chylomicrons in the space of Disse at 2--20 h after the onset of suckling revealed a substantial filtration effect of endothelial fenestrations on chylomicrons larger than 250 nm in diameter. Direct uptake of chylomicrons by parenchymal cells was observed to occur by pinocytosis; Kupffer cells endocytosed only very few chylomicrons, and endothelial cells were inactive in this respect.

A case of anomalous pulmonary venous drainage from the entire left lung associated with complete heart block

A 22-year-old female patient presenting complete atrioventricular block and giant P waves in electrocardiogram had anomalous pulmonary venous drainage from the entire left lung. There was normal drainage from the right lung and no associated atrial septal defect or other intracardiac abnormalities. After a permanent pacemaker was implanted, she manifested signs and symptoms of heart failure. Although the anomalous pulmonary vein was anastomosed to the left atrium, intractable heart failure continued. She died six months later after surgical intervention. Postmortem examination revealed diffuse interstitial fibrosis throughout the myocardium.