Search results for "Calcium"
showing 10 items of 1740 documents
Type II diabetics with macrovascular complications: polymorphonuclear leukocyte (PMN) filtration, PMN membrane fluidity and cytosolic Ca2+ content af…
1998
We evaluated polymorphonuclear (PMN) filtration parameters, membrane fluidity and cytosolic Ca2+ content in 21 normal subjects and in 18 type II diabetics with macrovascular complications (MVC). Evaluations were carried out at baseline and after in vitro activation prolonged for 5 and 15 min. PMA (4-phorbol 12-myristate 13-acetate) and fMLP (N-formyl-methionyl-leucyl-phenylalanine) were used as stimulating agents. TMA-DPH (1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene) was used as fluorescent probe for the membrane fluidity tests and Fura 2-AM for the cytosolic Ca2+ content. A significant variation was evident in PMN filtration parameters at 5 and 15 min. No variation was present i…
Ca2+ entry blockers inhibit prostaglandin F2 alpha-induced cerebrovascular contractile responses in goats.
1991
We examined the effects of extracellular Ca2+ withdrawal and of Ca2+ entry blockers on goat cerebrovascular responses to prostaglandin F2 alpha (PGF2 alpha). We measured isometric tension in isolated middle cerebral arteries, and cerebral blood flow (CBF) in unanesthetized animals. PGF2 alpha produced concentration-dependent contractions of isolated arteries. The contractions were partially inhibited by incubation in Ca(2+)-free medium (by 63.1 +/- 1.8% without ethyleneglycol-bis-(beta-amino-ethylether)-N,N,N',N'-tetra-a cetate (EGTA), and by 82.4 +/- 3.7% with EGTA). The Ca2+ entry blockers inhibited PGF2 alpha-elicited contraction and relaxed PGF2 alpha-precontracted arteries (nicardipine…
Intervention of two voltage-dependent calcium-entry pathways in the contractile response to acetylcholine and KCl in rat uterus.
1994
The contractile response of rat uterine smooth muscle was investigated. Verapamil and diltiazem concentration-dependently relax the sustained contractions induced by KCl (56 mmol/l) or acetylcholine (10(-4) mol/l). This inhibitory effect was not not freely reversed by washing the tissue and subsequently no contractile response was obtained in depolarized tissue, but a lower biphasic response (phasic and tonic) to acetylcholine was observed. Addition of cumulative concentrations of CaCl2 (1.2-19.2 mmol/l) induced a partial recovery of the contractile response to acetylcholine or KCl, but addition of MgCl2 (1.2-19.2 mmol/l did not. When the channel was reactivated by a third addition of KCl o…
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.
Use of Zoledronic Acid in a Neonate with Subcutaneous Fat Necrosis Complicated with Severe, Refractory Hypercalcemia.
2019
Objective Subcutaneous fat necrosis (SCFN) is a rare condition that may occur in the neonatal period. SCFN is an inflammatory disorder of the adipose tissue, usually found in full-term healthy infants who have a history of intrauterine or perinatal distress. It is usually a self-limited condition; however, in some cases, it can get complicated, leading to severe hypercalcemia that may be life-threatening. Study Design We report and describe a classic presentation of SCFN that led to severe hypercalcemia refractory to standard treatment. The diagnosis of SCFN was made based on the finding of subcutaneous nodules and of hypercalcemia. The serum calcium level reached 16.6 mg/dL. Hypercalcemia…
The influence of Ca2+ antagonists on the ciliary activity of the guinea pig trachea.
1990
The ciliary activity of the guinea pig tracheal respiratory epithelium was measured using a photoelectric device. Fourteen animals were administered 75 mg diltiazem/kg body weight 2 days, 1 day and 4 h prior to the investigation. Thirteen animals served as controls. In the pretreated group, the mean ciliary stroke frequency (13.4 +/- 3.0 Hz) was significantly lower (P = 0.02) than in the control group (16.6 +/- 3.7 Hz). The application of aerosolized 0.3 mmol/l nifedipine solution on the tracheal preparations of the control animals also significantly reduced the stroke frequency (P = 0.02). The ciliary activity never dropped beyond a frequency of about 8 Hz. The most probable interpretation…
Inhibition of calcium entry induced by cularines and isocrasifoline in uterine smooth muscle.
1991
Abstract The effects of nifedipine, papaverine and four benzylisoquinoline alkaloids (cularine, cularidine, celtisine and isocrasifoline) were studied in isolated rat uterus in order to clarify the mechanism of their relaxant action. All the compounds tested completely relaxed KCl-induced contractions and totally or partially inhibited oxytocin-induced rhythmic contractions. Only papaverine acted intracellularly, promoting relaxation of contractile responses induced by oxytocin or vanadate in a Ca 2+ -free medium. In spite of the structural relationship between papaverine and the other alkaloids, the mechanism of their relaxant action is not the same. The activities of cularine derivatives …
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…
Efficacy, tolerability and influence on "quality of life" of nifedipine GITS versus amlodipine in elderly patients with mild-moderate hypertension.
2001
The main purpose of this study was to compare efficacy, tolerability and influence on quality of life (QOL) of nifedipine gastrointestinal therapeutic system (NI) 30-60 mg once a day vs amlodipine (AM) 5-10 mg once a day in elderly patients with mild-moderate hypertension.This was a randomized, double-blind, parallel-group, multicenter study. After a 2-week single-blind placebo run-in, patients were randomized to either NI 30 mg or AM 5 mg. Responders continued on the same dosage for 16 additional weeks, while non-responders were titrated to 60 mg NI or 10 mg AM.Blood pressure was measured by mercury sphygmomanometer and efficacy equivalence of NI and AM tested by covariance analysis. Diast…