Search results for "Calcium"
showing 10 items of 1740 documents
Efecto in vitro de la adición de resinas de intercambio iónico sobre la biodisponibilidad de electrolitos en fórmulas de nutrición enteral artificial
2008
The in vitro effect of the addition of ion exchange resins on the bioavailability of electrolytes in artificial enteral feeding formulas Objective: To determine in vitro free ion concentration in three standard artificial enteral feeding formulas following the addition of ion exchange resins. Method: Three standard types of AEF were chosen: Osmolite HN®, Nutrison Standard® and Isosource Standard®. The ion exchange resins used were: Sodium Polystyrene Sulfonate and Calcium Polystyrene Sulfonate. 100 ml of AEF were mixed in a beaker with 1.5 g or 3 g of ion exchange resins for 48 hours at 37oC. Subsequently, the samples were precipitated and the supernatant obtained was used for determining t…
Über den Chemismus von Zustandsänderungen des Aktomyosins
1950
(1) By means of a simple method the conditions were investigated for contraction and relaxation of actomyosin (AM) under the influence of potassium, magnesium, and calcium ions, of adenosintriphosphate (ATP) or muscle-adenylic-acid and phosphocreatin.
Inhibition of uterine contractility by guanine-based purines in non-pregnant rats
2022
Growing evidence pointed out that guanine-based purines are able to modulate smooth muscle contractile activity of blood vessels and gastrointestinal tract. Since, so far, possible guanine-based purine modulation of uterine musculature is unknown, the aim of the present study was to investigate in vitro, using organ bath technique, guanosine and guanine efects on spontaneous uterine contraction, and uterine contraction induced by K+-depolarization and oxytocin in a non-pregnant rat. Guanosine, but not guanine, reduced the amplitude of spontaneous contraction of the uterine muscle in a dose-dependent manner. The inhibitory response was antagonized by S-(4-nitrobenzyl)-6-thioinosine (NBTI), a…
Quantitative Untersuchungen am Meerschweinchenvorhof �ber die Abh�ngigkeit der Digitoxigenin wirkung von der extracellul�ren Calciumkonzentration
1963
Es wurde uber einen weiten Bereich die Calciumkonzentration der Tyrodelosung verandert (0,9–9,0 mAq/l) und unter diesen Bedingungen die Konzentrationswirkungsbeziehungen fur verschiedene Digitoxigenindosen (1 × 10−7, 3 × 10−7, 5 × 10−7, 7 × 10−7 und 1 × 10−6 g/ml) am Meerschweinchenvorhof untersucht. Aus den Befunden geht hervor, das uber den gesamten untersuchten Bereich unter therapeutischen und toxischen Bedingungen ein eindeutiger Wirkungszusammenhang zwischen Digitoxigenin und Calcium besteht.
�ber den Einflu� von Mangan-Ionen auf die positiv inotrope Wirkung von Adrenalin, Theophyllin und Digitoxigenin an isolierten Meerschweinchenvorh�fen
1969
The influence of bivalent manganese ions (Mn++) on the positive inotropic effect of adrenaline, theophylline, and digitoxigenin was studied in isolated, electrically driven left guinea-pig auricles in phosphate-free Tyrode's solutions with different extracellular calcium concentrations ([Ca]e; 0.45; 1.8; 7.2 mM).
�ber den Mechanismus der positiv inotropen Wirkung von Theophyllin am Warmbl�terherzen
1971
In order to further elucidate the mechanism of the positive inotropiceffect of theophylline (T) in mammalian cardiac muscle, the influence of T on contractile force, extracellular space,45Ca uptake,45Ca release, and total myocardial calcium concentration was investigated in isolated, electrically driven (frequency 170 beats/min) or quiescent left guinea-pig atria. The investigations were performed in Tyrode solution containing 0.45 mM CaCl2. T concentration was 5×10−4 g/ml. Under these conditions, T exerted maximal positive inotropic but no toxic effects, that is, it did not cause contractures or arrythmias within 60 min (Fig. 1). The experiments provide evidence that T increases the rate o…
Influence of intracellular sodium concentration on calcium influx in isolated guinea pig auricles.
1969
Effect of a "therapeutic" concentration of digitoxigenine on myocardial potassium and sodium content in Ca-poor media.
1972
The effect of 3·10−7 g/ml digitoxigenine on cellular K and Na concentrations, [K]i and [Na]i, water content, extracellular space, and contractile force was investigated in isolated electrically stimulated left guinea-pig auricles at reduced extracellular Ca concentration (0.45 mM). Digitoxigenine, which increased contractile force without producing arrhythmias or contractures, decreased [K]i and enhanced [Na]i. Water content and extracellular space remained unchanged. It is concluded that digitoxigenine can decrease myocardial [K]i and increase [Na]i even in “therapeutic” concentrations, provided that the experiments are performed in Ca-poor media.
The cholinergic 'pitfall': acetylcholine, a universal cell molecule in biological systems, including humans.
1999
1. Acetylcholine (ACh) represents one of the most exemplary neurotransmitters. In addition to its presence in neuronal tissue, there is increasing experimental evidence that ACh is widely expressed in pro- and eukaryotic non-neuronal cells. Thus, ACh has been detected in bacteria, algae, protozoa, tubellariae and primitive plants, suggesting an extremely early appearance of ACh in the evolutionary process. 2. In humans, ACh and/or the synthesizing enzyme, choline acetyltransferase, has been demonstrated in epithelial cells (airways, alimentary tract, urogenital tract, epidermis), mesothelial (pleura, pericardium) and endothelial and muscle cells. In addition, immune cells express the non-ne…