Search results for "Magnesium"
showing 10 items of 490 documents
Characterization of choline efflux from the perfused heart at rest and after muscarine receptor activation.
1986
The resting efflux of choline from perfused chicken hearts varied from 0.4 to 2.6 nmol/g min, but was constant for at least 80 min in the individual experiments. The rate of choline efflux was found to be equal to the rate of choline formation in the heart, which, from the following reasons, was essentially due to hydrolysis of choline phospholipids. Cardiac content of choline phospholipids (7,200 nmol/g) was much higher than that of acetylcholine (5.5 nmol/g). Resting release of acetylcholine was 0.016 nmol/g min and, after inhibition of cholinesterase, only about 0.1 nmol/g min. Resting efflux of choline was reduced by mepacrine, a phospholipase A2 inhibitor, by perfusion with a Ca2+-free…
MAGNESIUM METABOLISM IN INSULIN RESISTANCE, METABOLIC SYNDROME, AND TYPE 2 DIABETES MELLITUS
2007
Magnesium plays a key role in regulating insulin action, insulin-mediated glucose uptake, and vascular tone. Intracellular magnesium depletion may result in a defective tyrosine—kinase activity at the insulin receptor level, in a postreceptorial impairment in insulin action, and clinically in a worsening of insulin resistance. Intra- and extracellular alterations of magnesium metabolism have been identified in clinical states characterized by insulin resistance, such as metabolic syndrome, hypertension, altered glucose tolerance, type 2 diabetes, and aging. Several studies, from our and other’s groups, have confi rmed the clinical relevance of alterations of magnesium homeostasis in these c…
Early developmental alterations of low-Mg2+ -induced epileptiform activity in the intact corticohippocampal formation of the newborn mouse in vitro.
2005
Abstract The generation, propagation and pharmacological properties of low-Mg 2+ -induced epileptiform activity were examined in the intact corticohippocampal formation (CHF) of the newborn (P0–4) mouse in vitro. Multi-site field potential recordings in dentate gyrus (DG), CA3, CA1, entorhinal cortex (EC) and temporal cortex (TC) revealed in 0.2 mM Mg 2+ -containing ACSF a stable pattern of spontaneous epileptiform activity consisting of recurrent ictal-like events (ILEs) and interictal events (IEs). Although this activity could be consistently observed as early as P0, ILEs were smaller in amplitude, less frequent and showed a slower onset in P0–2 as compared to P3–4 animals. In all age gro…
Role of magnesium in insulin action, diabetes and cardio-metabolic syndrome X
2003
Magnesium (Mg) is one of the most abundant ions present in living cells and its plasma concentration is remarkably constant in healthy subjects. Plasma and intracellular Mg concentrations are tightly regulated by several factors. Among them, insulin seems to be one of the most important. In vitro and in vivo studies have demonstrated that insulin may modulate the shift of Mg from extracellular to intracellular space. Intracellular Mg concentration has also been shown to be effective in modulating insulin action (mainly oxidative glucose metabolism), offset calcium-related excitation-contraction coupling, and decrease smooth cell responsiveness to depolarizing stimuli. A poor intracellular M…
Haliotis tuberculata hemocyanin (HtH): analysis of oligomeric stability of HtH1 and HtH2, and comparison with keyhole limpet hemocyanin KLH1 and KLH2
2000
The multimeric/higher oligomeric states of the two isoforms of Haliotis tuberculata hemocyanin (HtH1 and HtH2) have been assessed by transmission electron microscopy (TEM) of negatively stained specimens, for comparison with previously published structural data from keyhole limpet hemocyanin (KLH1 and KLH2) [see Harris, J.R., Gebauer, W., Guderian, F.U., Markl, J., 1997a. Keyhole limpet hemocyanin (KLH), I: Reassociation from Immucothel followed by separation of KLH1 and KLH2. Micron, 28, 31-41; Harris, J.R., Gebauer, W., Söhngen, S.M., Nermut, M.V., Markl, J., 1997b. Keyhole limpet hemocyanin (KLH). II: Characteristic reassociation properties of purified KLH1 and KLH2. Micron, 28, 43-56; H…
Spontaneous labour at term is associated with fetal monocyte activation.
1999
SUMMARYThe aetiology of both term and preterm labour remains incompletely understood. Maternal infectious diseases as well as intra-uterine infections were shown to be a well established cause of uncontrollable preterm delivery, indicating that inflammatory reactions, regulated by maternal immunecompetent cells, are implicated in labour-promoting mechanisms. To investigate the possibility that the activation of the fetal immune system may be involved in labour induction, we examined cytokine production patterns of different cord blood cell populations obtained from neonates after spontaneous onset of normal term labour and vaginal delivery (n = 25), vaginal delivery but induced term labour …
An Ion Exchange Membrane Crystallisation reactor for Magnesium recovery from brines
2015
CrIEM technology is a novel ion exchange application that allows reactive crystallization for separation of valuable species (e.g. Mg from brines) with a large flexibility in the choice of reactants.
Microwave response of bulk MgB2 samples of different granularity
2006
The microwave response of three high-density bulk MgB2 samples has been investigated in the linear and nonlinear regimes. The three samples, characterized by different mean size of grains, have been obtained by reactive infiltration of liquid Mg in powdered B preforms. The linear response has been studied by measuring the microwave surface impedance; the nonlinear response by detecting the power radiated by the sample at the second-harmonic frequency of the driving field. Our results suggest that bulk MgB2 prepared by the liquid Mg infiltration technique is particularly promising for manufacturing resonant cavities operating at microwave frequencies.
Copolymerization of ethylene with higher 1-olefins over vanadium catalyst supported on Al(i-Bu)3 modified magnesium carrier
2008
Badano proces kopolimeryzacji etylenu z wyższymi 1-olefinami (C6-C12) wobec katalizatora wanadowego (VOCl3) immobilizowanego na nośniku magnezowym MgCl2 (THF) 2 modyfikowanym z zastosowaniem Al(i-Bu) 3. W charakterze aktywatora nośnikowego prekatalizatora wanadowego zastosowano Et2AlCl. Stwierdzono, że aktywność takiego układu katalitycznego jest porównywalna z aktywnością katalizatora z prekursorem wanadowym osadzonym na niemodyfikowanym nośniku magnezowym. Zaobserwowano także, że wprowadzenie komonomeru do środowiska reakcji powoduje niewielkie zmniejszenie wydajności procesu w porównaniu z homopolimeryzacją etylenu, postępującą w miarę wzrostu stężenia komonomeru w środowisku reakcji. Do…
Synthesis, electron microscopy and X-ray characterization of oxymagnesite, MgO·2MgCO3, formed from amorphous magnesium carbonate
2014
At present, the peculiar compound called oxymagnesite, MgO·2MgCO3, an intermediate formed during thermal decomposition of hydrated magnesium carbonates, has only been described a handful of times without a distinct description of its formation or morphology. In the current work we present the first scanning and transmission electron microscopy images of an oxymagnesite crystal together with its crystallographic data. Oxymagnesite was synthesized in a controlled manner via decomposition of amorphous magnesium carbonates (AMCs) subjected to varying relative humidity. We show that oxymagnesite is formed only when AMC is hydrated above a certain level, which we attribute to structural inequival…