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  • 1
    ISSN: 1435-1803
    Keywords: myocardium ; ethanol ; ultrastructure ; morphometry ; capillaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Männliche Kaninchen wurden 3 Wochen lang mit Äthanol gefüttert. 10 ml einer 20%igen Äthanollösung wurden täglich mit einer Schlundsonde verabreicht. Die makroskopische, mikroskopische und ultrastrukturelle Untersuchung der Herzen ergab keine eindeutigen strukturellen Veränderungen. Morphometrisch waren die Endothelzellen der Kapillaren verändert, während die Muskelzellen keine abnormen quantitativen Parameter aufwiesen. Die Daten zeigen, daß die numerische Dichte der Endothelzellen erhöht ist, während die Volumendichte nicht signifikant verändert ist. Diesen Typus eines quantitativen Reaktionsmusters kann man als „Proliferation” charakterisieren. Die Proliferation beruht möglicherweise auf Äthanol-induzierten metabolischen Veränderungen, die denen bei chronischer Hypoxie ähnlich sind. Andererseits gibt es Anhaltspunkte dafür, daß die Reaktion Teil einer allgemeinen Mesenchymaktivierung nach Alkoholgabe ist, die in verschiedenen Organen beobachtet werden kann. Die Veränderung entspricht wahrscheinlich der frühen Phase einer Kapillarproliferation.
    Notes: Summary Male rabbits were fed with ethanol for 3 weeks. 10 ml of a 20% ethanol solution were applied daily with a stomach tube. The macroscopic, histologic and ultrastructural investigation of the hearts did not reveal any structural alterations. Morphometrically, the endothelial cells of the capillaries were changed, whereas the muscle cells did not show any abnormalities. The quantitative data indicate that the numerical density of endothelial cells is increased, whereas the volume density is not changed. This type of quantitative reaction pattern may be characterized as “proliferation” of endothelial cells. The proliferation is possibly related to ethanol-induced metabolic changes similar to chronic hypoxia. On the other hand, there is some evidence that the alteration is part of a general activation of mesenchymal cells in various organs after ethanol ingestion. The alteration is probably an early stage of the proliferation of capillaries.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1435-1803
    Keywords: myocardium ; hypertrophy ; capillaries ; stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stereological investigations on myocardial capillaries provided evidence that the common estimator of capillarity, the capillary density (i.c., number of capillary profiles per unit transverse sectional area), underestimates the true capillary supply since the capillary axes are not oriented perfectly in parallel to the myofiber axes. Recently, we studied the “true” capillarity, i.c., the length density of capillaries (Lv=capillary length per capillary volume), in some experimental models of cardiac hypertrophy which have been published elsewhere. It has been shown that Lv decreases in renovascular hypertension, but is maintained in physical exercise and after chronic thyroxin application. However, the growth pattern of capillaries in hypertrophic hearts has not yet been analyzed. In the present paper it is demonstrated that important information on the capillary network can be derived from the two-dimensional capillary-to-fiber ratios (2D CFR: capillary profiles per myofiber profiles in transverse sections) and from the three-dimensional capillary-to-fiber ratios (3D CFR: capillary length per unit myofiber length). Increase in both suggests neoformation of additional capillary branches in parallel connection. Retrospective analysis of the quantitative data indicates that in hypertrophy induced by physical exercise or by chronic thyroxin application capillary neoformation in parallel connection counterbalances increase of oxygen diffusion distance due to myofiber enlargement. In renovascular hypertension, capillary neoformation in parallel connection does not occur. Studies on normal growth indicated both a slight decrease of Lv of capillaries, as well as a continuous neoformation of additional capillary branches.
    Type of Medium: Electronic Resource
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