Search results for "element"

Comparative study of the rat uterine smooth muscle relaxant activity of three bisbenzyltetrahydroisoquinolines with tetrandrine

1993

Abstract The relaxant activity of three bisbenzyltetrahydroisoquinolines—obaberine, popisonine and lindoldhamine—was examined in rat isolated uterus and their inhibitory potencies were compared with that of tetrandrine. All alkaloids tested relaxed KCl-depolarized rat uterus and totally or partially inhibited oxytocin-induced rhythmic contractions. The degree of methylation of the free phenolic hydroxy groups and the loss of one diarylether bridge influence the potency of relaxant action of these alkaloids. Only alkaloids with absolute configuration 1R,1′S or 1R1′R acted intracellularly, promoting relaxation of contractile responses induced by oxytocin or vanadate in a Ca2+-free medium.

Differential blockade by nifedipine and ω-conotoxin GVIA of α1- and β1-adrenoceptor-controlled calcium channels on motor nerve terminals of the rat

1990

Electrically evoked release of [3H]acetylcholine ([3H]ACh) from the rat phrenic nerve and its facilitation by stimulation of presynaptic alpha 1- and beta 1-adrenoceptors were investigated in the absence and presence of nifedipine and omega-conotoxin GVIA. Both calcium channel antagonists did not modify electrically evoked [3H]ACh release, but selectively blocked the effect triggered by both facilitatory adrenergic receptors. The increase in [3H]ACh release mediated via beta 1-adrenoceptor activation was abolished by low concentrations (1 nM) of omega-conotoxin GVIA, whereas nifedipine (100 nM) abolished the facilitatory effect mediated via alpha 1-adrenoceptor stimulation. Therefore, the b…

Inhibitory effects of okadaic acid on rat uterine contractile responses to different spasmogens

1997

In the present study, we examined the effects of okadaic acid, a selective inhibitor of type I and 2A protein phosphatases, on the mechanical responses evoked by oxytocin, K + - and Na + -modified solutions and ouabain in estrogen-primed rat myometrium. Oxytocin elicited a rapid, phasic contraction followed by rhythmic oscillations. The phasic response was partially resistant to the absence of external Ca 2+ . Okadaic acid (1 μM) and the L-type calcium channel blocker nifedipine (1 μM) abolished the oscillatory component and reduced the initial, phasic response to about 80% of the control response. High K + (60 mM) solution, ouabain (1 mM), K + -free medium and low Na + (25 mM) solution ind…

New Viewpoint in Exaggerated Increase of PtiO2 With Normobaric Hyperoxygenation and Reasons to Limit Oxygen Use in Neurotrauma Patients

2018

The Oxygen Reserve Index in anesthesiology: a superfluous toy or a tool to individualize oxygen therapy?

2018

Theoretical Basis Versus Clinical Practice of Oxygen Parameters of Blood

1996

Under optimal conditions all oxygen parameters of human blood are defined at a theoretical basis, accepted and understood by the clinicians, measured correctly by instruments of different manufacturers and, therefore, leading to clear diagnoses for the patients.

Gadolinium accumulation after contrast-enhanced magnetic resonance imaging: Which implications in patients with Crohn's disease?

2017

Crohn's disease (CD) is a chronic inflammatory condition of the bowel, characterized by an alternation of remission and relapse phases, leading to a progressive intestinal damage with loss of function. Magnetic resonance enterography has been widely used in the past for the evaluation of fistulizing disease, but its use increased over time, being considered helpful in different moments of disease course. Intravenous injection of Gadolinium-based contrast agents has been demonstrated to be crucial to assess mucosal inflammation, transmural involvement, and extraintestinal disease. Recently, Gadolinium accumulation in human tissues has been increasingly reported, although clinical implication…

PaO2oscillations caused by cyclic alveolar recruitment can be monitored in pig buccal mucosa microcirculation

2012

BACKGROUND Cyclic alveolar recruitment and derecruitment play a role in the pathomechanism of acute lung injury and may lead to arterial partial pressure of oxygen (PaO(2) ) oscillations within the respiratory cycle. It remains unknown, however, if these PaO(2) oscillations are transmitted to the microcirculation. The present study investigates if PaO(2) oscillations can be detected in the pig buccal mucosa microcirculation. METHODS Respiratory failure was induced by surfactant depletion in seven pigs. PaO(2) oscillations caused by cyclic recruitment and derecruitment were measured in the thoracic aorta by fast fluorescence quenching of oxygen technology. Haemoglobin oxygen saturation, haem…

Dosimetric characterization of two radium sources for retrospective dosimetry studies

2015

Purpose: During the first part of the 20th century, Ra-226 was the most used radionuclide for brachytherapy. Retrospective accurate dosimetry, coupled with patient follow up, is important for advan ...

Calcium Dependence of the Mechanical Response Evoked by Okadaic Acid in Smooth Muscle

1995

The effects of okadaic acid (OA), obtained from a culture of the marine dinoflagellate Prorocentrum Lima were studied on isolated strips of rat myometrium. The contractile response evoked by OA at 5, 10, and 20 μM in normal physiological solution was unaffected in the presence of tetrodotoxin (10 μM), indomethacin (3 μM), or a cocktail of antagonists which blocked muscarinic, adrenergic, histaminergic, serotonergic, and opioid receptors. Similarly, the response to OA was unaffected in the presence of nifedipine at a concentration (1 μM) which completely or highly blocked the response to KCl (60 mM), oxytocin (1 μM), or acetylcholine (100 μM). In a Ca 2+ -free 1 mM EGTA-containing solution, …