Search results for "Magnesium"
showing 10 items of 490 documents
Modulatory role of magnesium on the contractile response of rat aorta to several agonists in normal and calcium-free medium.
1993
Abstract Acute withdrawal of external Mg2+ increased basal tone of rat isolated aorta incubated in the presence of Ca2+. Above normal levels of Mg2+ (1–4 Mm) inhibited basal tone while much higher levels of the divalent cation (64–256 Mm) evoked contractile responses regardless of the presence of Ca2+. Contractile responses to noradrenaline (1μm) and KCl (80 Mm) were inhibited by addition of cumulative concentrations of Mg2+. Acetylcholine-induced contractions in the presence of physiological concentrations of Mg2+ (1 Mm) decreased gradually to the basal tone, but a sustained contraction was observed in the absence of this ion. In Ca2+-free medium, acetylcholine-induced phasic responses ind…
Toenail cerium levels and risk of a first acute myocardial infarction: the EURAMIC and heavy metals study.
2006
The association between cerium status and risk of first acute myocardial infarction (AMI) was examined in a case-control study in 10 centres from Europe and Israel. Cerium in toenails was assessed by neutron activation analysis in 684 cases and 724 controls aged 70 years or younger. Mean concentrations of cerium were 186 and 173 microg/kg in cases and controls, respectively. Cerium was positively associated with low socio-economic status, smoking, mercury, zinc and scandium (p0.001). Cases had significantly higher levels of cerium than controls after adjustment for age and centre (case-control ratio 1.074; 95% CI 1.002-1.151) and increased in further adjustment for other cardiovascular risk…
Insulin-Mimetic Action of Vanadate
2001
Abstract — — The insulin-mimetic effect of vanadate is well established, and vanadate has been shown to improve insulin sensitivity in diabetic rats and humans. Although the exact mechanism(s) remain undefined, we have previously demonstrated a direct relation of intracellular free magnesium (Mg i ) levels to glucose disposal, to insulinemic responses following glucose loading, and to insulin-induced ionic effects. To investigate whether the insulin-mimetic effects of vanadate could similarly be mediated by Mg i , we utilized 31 P-nuclear magnetic resonance spectroscopy to measure Mg i in erythrocytes from normal (NL, n=10) and hypertensive (HTN, n=12) subjects, before and after incubation…
Domperidone plus Magnesium Hydroxide and Aluminum Hydroxide: A Valid Therapy in Children with Gastroesophageal Reflux: A Double-Blind Randomized Stud…
1994
To evaluate the efficacy of different drug combinations in treating severe gastroesophageal reflux (GER), we studied 80 children with GER. The patients were randomly divided into four groups: group A was treated with domperidone plus magnesium hydroxide and aluminum hydroxide, group B with domperidone plus alginate, group C with domperidone alone, and group D received placebo. At the time of diagnosis and 8 weeks after treatment the patients were clinically evaluated and underwent 24-h continuous esophageal pH monitoring. After treatment a complete regression of symptoms was observed in 16 of 20 patients in group A, in 8 of 20 in group B (A versus B, p < 0.018), in 9 of 20 in group C (A ver…
Serum ionized magnesium levels in relation to metabolic syndrome in type 2 diabetic patients
2006
Objective: To evaluate circulating serum ionized magnesium (i-Mg) concentrations in patients with type 2 diabetes mellitus, and to investigate its relationship with the components of the metabolic syndrome. Design: cross-sectional study. Setting: Outpatients' service for diabetic patients at the University Hospital of Messina, Italy. Subjects: 290 patients with type 2 diabetes mellitus. Measures of Outcome: Serum i-Mg was measured by ion selective electrode. Age, gender, body mass index (BMI), waist circumference, blood pressure, fasting glucose, HbA1c, HDL cholesterol, triglycerides, and urinary albumin excretion rate (UAER) were considered in the analyses. Patients with hypomagnesemia, de…
Altered ionized magnesium levels in mild-to-moderate Alzheimer's disease.
2011
Abstract. Magnesium deficiency is present in several chronic, age-related diseases, including cardiovascular, metabolic and neurodegenerative diseases. Alzheimer’s disease (AD) is the most common cause of dementia. The aim of the present study was to study magnesium homeostasis in patients with mild to moderate AD. One hundred and one elderly (≥65 years) patients were consecutively recruited (mean age: 73.4±0.8 years; M/F: 42/59). In all patients, a comprehensive geriatric assessment was performed including cognitive and functional status. Admission criteria for the AD group (diagnosed according to the DSM-IV and the NINCDS-ADRDA criteria) included: mild to moderate cognitive impairment (MM…
Effect of different treatments in calcium-free medium on basal tone and contractile responses of guinea pig tracheae.
1995
Acetylcholine (ACh; 0.1 mmol/l) and KCl (80 mmol/l) induce a biphasic contractile response in isolated guinea pig tracheae maintained at 37 degrees C either in the presence or absence of extracellular Ca2+. Exposure of the tissue to Ca(2+)-free solution evokes a significant decrease in basal tone and the sources of Ca2+ appear to be decreased by prolonged agonist stimulation, and even more by successive agonist stimulation. After an incubation period of 20 min in Ca(2+)-containing solution, the response is restored. Mg(2+)-depletion in Ca(2+)-free medium increased the contractile response to ACh, but not to KCl, and delayed the tonic component of the next contraction elicited in Ca(2+)-cont…
Identification of carbonate-rich outcrops on Mars by the Spirit rover.
2010
Ancient Carbonate Minerals on Mars The historical presence of liquid water on Mars together with a CO 2 -rich atmosphere should have resulted in the accumulation of large deposits of carbonate minerals. Yet, evidence for the presence of carbonates on the surface of Mars has been scarce. Using data collected by the Mars Exploration Rover, Spirit, Morris et al. (p. 421 , published online 3 June; see the Perspective by Harvey ) now present evidence for carbonate-rich outcrops in the Comanche outcrops within the Gusev crater. The carbonate is a major outcrop component and may have formed in the Noachian era (∼4 billion years ago) by precipitation from hydrothermal solutions that passed through …
Mg impurity in helium droplets.
2011
Within the diffusion Monte Carlo approach, we have determined the structure of isotopically pure and mixed helium droplets doped with one magnesium atom. For pure 4He clusters, our results confirm those of M. Mella et al. [J. Chem. Phys. 123, 054328 (2005)] that the impurity experiences a transition from a surface to a bulk location as the number of helium atoms in the droplet increases. Contrarily, for pure 3He clusters Mg resides in the bulk of the droplet due to the smaller surface tension of this isotope. Results for mixed droplets are presented. We have also obtained the absorption spectrum of Mg around the 3s3p 1P_1 <-- 3s2 1S_0 transition.
Study of magnesium and aluminum alloys absorption coefficient during Nd:YAG laser interaction
2007
International audience; In laser processes, the absorption factor of laser Nd:YAG by metals plays a very important role. In order to model laser welding, we need to know its evolution during the process. The theoretical calculation does not enable the prediction of the absorption factor in the case of a keyhole mode. It is difficult to predict the effect of plasma and recoil pressure on the shape of the keyhole. In this paper, an integrating sphere is used to determine the absorption factor during the laser process, which is carried out on two types of magnesium alloys (WE43 and RZ5) and an aluminum alloy. We obtain the evolution in time of the absorption factor according to different steps…