[Two years of experience with in-vitro testing of malignant ovarian tumors (proceedings)].
Explore the source record for details and available documents.
Antineoplastic Agents↗
Biomedical subjects
M Gräfe
Publications and source records attributed to M Gräfe.
The influence of food intake on the development of structural and functional adaptation following ileal resection in the rat.
The present study was undertaken to determine the influence of hyperphagia on the adaptive changes occurring in the rat jejunal mucosa as a result of intestinal resection. One group of resected rats was subjected to pair feeding with a sham-operated population, whilst another group was nourished ad libitum. The animals which ate ad libitum developed hypertrophy of the mucosa which was accompanied by increased glucose absorption in vivo without changes in enzyme levels. These alterations were much less pronounced in the pair-fed group of resected animals, a finding that indicates that the adaptive changes are at least partially influenced by increased luminal nutrition.
Adaptation, Physiological↗
Electrophysiological properties of human coronary endothelial cells.
The electrophysiological properties of human coronary endothelial cells (HCEC) of macro- and microvascular origin were studied using the whole-cell configuration of the patch-clamp technique. The membrane potential of confluent HCEC (-41.9 +/- 3.9 mV (mean +/- SEM, n = 32) for macro- and -33.6 +/- 2.6 mV (n = 64) for microvascular cells, respectively) was less negative than the K+ equilibrium potential. Inward currents of isolated cells at potentials below the K+ equilibrium potential were blocked by external Ba2+ (1 mM), inactivated due to time- and voltage-dependent block caused by external Na+, and their amplitudes were enhanced by increasing extracellular [K+]; these currents were identified as inwardly rectifying K+ currents. Some isolated cells displayed outwardly directed K+ currents which were abolished after replacement of Cs+ for K+ on both sides of the membrane. Voltage-dependent Ca2+ currents could not be observed in isolated HCEC. Hyperpolarizations induced by vasoactive agonists have been observed in some endothelial cells from different species. In contrast, extracellularly applied ATP (adenosine-5'-triphosphate) and ADP (adenosine-5'-diphosphate) at micromolar concentrations depolarized confluent HCEC, whereas adenosine had no effect on resting potentials (RP), indicating that the nucleotide-induced depolarizations were mediated via P2- purinoceptors. These depolarizations occurred even after replacement of N-methyl-D-glucamine for extracellular Na+, indicating that Ca(2+)-influx was involved. There were no marked differences in the electrophysiological properties between cells of macro and microvascular origin.
Adenosine Triphosphate↗
Induction of human vascular endothelial stress fibres by fluid shear stress.
Endothelial cells of the arterial vascular system and the heart contain straight actin filament bundles, of which there are few, if any, in the venous endothelium. Since stress fibre-containing endothelial cells within the vascular system tend to be located at sites exposed to particularly high shear stress of blood flow, we have investigated, in an experimental rheological system (Fig. 1), the response of the endothelial actin filament skeleton to controlled levels of fluid shear stress. Here we report that endothelial stress fibres can be induced by a 3-h exposure of confluent monolayer cultures of human vascular endothelium to a fluid shear stress of 2 dynes cm-2, approximately the stress occurring in human arteries in vivo. Fourfold lower levels of shear stress that normally occur only in veins, had no significant effect on the endothelial actin filament system. The formation of endothelial stress fibres in response to critical levels of fluid shear stress is probably a functionally important mechanism that protects the endothelium from hydrodynamic injury and detachment.
Actinin↗