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PubMed2005

The mineral phase in the cuticles of two species of Crustacea consists of magnesium calcite, amorphous calcium carbonate, and amorphous calcium phosphate.

The cuticules (shells) of the woodlice Porcellio scaber and Armadillidium vulgare were analysed with respect to their content of inorganic material. It was found that the cuticles consist of crystalline magnesium calcite, amorphous calcium carbonate (ACC), and amorphous calcium phosphate (ACP), besides small amounts of water and an organic matrix. It is concluded that the cuticle, which constitutes a mineralized protective organ, is chemically adapted to the biological requirements by this combination of different materials.

Animals↗
PubMed1969

Studies on the mode of action of vasopressin on the isolated proximal colon of the guinea-pig.

1. Contractions of guinea-pig isolated proximal colon produced by vasopressin are not affected by methyloxytocin (a compound that blocks pressor effects of vasopressin).2. Vasopressin contractions are inhibited by replacement of sodium with mannitol or sucrose, elevation of potassium or magnesium concentrations, the presence of the metabolic inhibitors sodium azide and triethyl tin or tetrodotoxin in the bathing fluid. Contractions produced by histamine or choline esters are comparatively insensitive to these procedures.3. Contractions of rat isolated uterus following vasopressin, oxytocin and methacholine are equally affected by replacement of sodium, increase of potassium or magnesium or addition of sodium azide.4. Neither vasopressin contractions nor contractions caused by transmural stimulation were consistently affected by morphine (10(-6) g/ml.) or hyoscine (10(-7) g/ml.) although both were reduced by anoxia or cooling the tissue. Morphine did not reduce the output of acetylcholine from stimulated colon.5. It is concluded that the action of vasopressin on proximal colon is unlike its action on other smooth muscle and is mediated by nervous tissue.

Acetylcholine↗
PubMed2001

Monomeric and dimeric amidinate complexes of magnesium.

Treatment of anhydrous magnesium bromide with 2 equiv of (1,3-di-tert-butylacetamidinato)lithium, (1,3-di-tert-butylbenzamidinato)lithium, (1,3-diisopropylacetamidinato)lithium, or (1-tert-butyl-3-ethylacetamidinato)lithium (prepared in situ from the corresponding carbodiimide and alkyllithium) in diethyl ether at ambient temperature afforded bis(N,N'-di-tert-butylacetamidinato)magnesium (81%), bis(N,N'-di-tert-butylbenzamidinato)magnesium (82%), bis[bis(N,N'-diisopropylacetamidinato)magnesium] (70%), or bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium] (93%), respectively, as colorless crystalline solids. These complexes were characterized by spectral and analytical data and by single-crystal X-ray crystallography for bis(N,N'-di-tert-butylbenzamidinato)magnesium, bis[bis(N,N'-diisopropylacetamidinato)magnesium], and bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium]. In the solid-state structure, bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium] was found to contain mu,eta(2):eta(1)-amidinato ligands. Bis[bis(N,N'-diisopropylacetamidinato)magnesium] exists in a monomer-dimer equilibrium in toluene-d(8) between -20 and +60 degrees C. A van't Hoff analysis of this equilibrium afforded DeltaH degrees = -14.7 +/- 0.2 kcal/mol, DeltaS degrees = -44.9 +/- 0.2 cal/(mol.K), and DeltaG degrees (298 K) = -1.32 +/- 0.2 kcal/mol. The potential application of the new compounds in the chemical vapor deposition of magnesium-doped group 13 compound semiconductor films is discussed.

Journal Article↗
PubMed1985

Efficacy of activated charcoal and magnesium citrate in the treatment of oral paraquat intoxication.

The binding capacity of activated charcoal for paraquat was evaluated in vitro and in vivo and compared with Fuller's earth. In vitro activated charcoal absorbs paraquat and is as effective as Fuller's earth. Activated charcoal's absorbing capacity for paraquat is increased when it is suspended in magnesium citrate and is maximal at pH 7.8. Paraquat (200 mg/kg) administered orally to male mice, followed 30 minutes later by activated charcoal, Fuller's earth (4 gm/kg), and magnesium citrate (0.01 cc/gm) resulted in a survival rate of 31% in the controls, 63% in the activated charcoal and Fuller's earth groups, and 69% in the magnesium citrate group (P values not significant). When activated charcoal was administered concomitantly with magnesium citrate, the survival rate was improved significantly to 94% (P less than 0.01). The efficacy and greater availability of activated charcoal and magnesium citrate make these materials the treatment of choice for gastrointestinal decontamination in oral paraquat poisoning.

Absorption↗
PubMed1997

Pure silicate fragment in a recurrent stone former of calcium oxalate.

Long-time oral intake of magnesium-silicate-containing drugs is thought to be a causative factor inducing silicate urolithiasis. Besides, magnesium seems to play an anti-urolithogenic part in the formation of calcium oxalate stones. We report a recurrent calcium oxalate former who had been treated with magnesium aluminometasilicate antacid for gastric ulcer for approximately 17 years. One of the fragments found during extracorporeal shock wave lithotripsy was identified as 100% silicate. Deposition of silica was also found on other fragments. A large dose of magnesium (given in a part of the drug) might have little influence on the formation of calcium oxalate.

Aluminum Compounds↗
PubMed2006

Waste lime as a potential cation source in the phosphate crystallization process.

In this study, the feasibility of waste lime as a potential cation source in phosphate crystallization process was investigated using laboratory scale up flow reactors, adopting sequencing batch type configuration. This research focused on its successful application in a novel sludge treatment process, which is comprised of a high performance fermenter (operating conditions: 55 degree C and pH 9) followed by a crystallization reactor. In the struvite precipitation test using synthetic wastewater, considerable nutrient removal (about 60%) in the form of ammonia and phosphate was observed within 0.5-1 hr of retention time, and only small amounts (< 5%) of ammonia stripping occurred naturally due to the alkaline (pH 9) characteristic of the feed substrate. By replacing the synthetic wastewater with the fermentation effluent, the optimal dosage of magnesium salt for struvite precipitation was 0.86 g Mg g(-1) P, similar to the mass ratio of the struvite. The optimal dosage of waste lime was 0.3 g 1(-1), resulting in 80 % of NH4-N and 41% of PO3-P removal, at about 3 hrs of retention time. Microscopic analysis showed that amorphous crystals were mainly observed in the settled solids with waste lime addition whereas prism-like crystals were found in the system with magnesium salt added. Mass balance analysis in full-scale model plants (Q=158,880 m(3)d(-1)) based on the present experimental results revealed that nutrient recycle loading from side stream to main liquid stream would be significantly reduced. The results of the experiment reveal that reuse of industrial waste lime in a nutrient recovery system has the various advantages such as higher economical benefits and sustainable treatment of the industrial waste.

Calcium Compounds↗
PubMed1978

Modification of Rhodospirillum rubrum ribulose bisphosphate carboxylase with pyridoxal phosphate. 1. Identification of a lysyl residue at the active site.

Ribulose 1,5-bisphosphate carboxylase isolated from Rhodospirillum rubrum was strongly inhibited by low concentrations of pyridoxal 5'-phosphate. Activity was protected by the substrate ribulose bisphosphate and to a lesser extent by other phosphorylated compounds. Pyridoxal phosphate inhibition was enhanced in the presence of magnesium and bicarbonate, but not in the presence of either compound alone. Concomitant with inhibition of enzyme activity, pyridoxal phosphate forms a Schiff base with the enzyme which is reversible upon dialysis and reducible with sodium borohydride. Subsequent to reduction of the Schiff base with tritiated sodium borohydride, tritiated N6-pyridoxyllysine could be identified in the acid hydrolysate of the enzyme. Only small amounts of this compound were present when the reduction was performed in the presence of carboxyribitol bisphosphate, an analogue of the intermediate formed during the carboxylation reaction. Therefore, it is concluded that pyridoxal phosphate modifies a lysyl residue close to or at the active site of ribulose bisphosphate carboxylase.

Bicarbonates↗
PubMed1999

[Personal experience with administration of Smektit (hydrated magnesium aluminum silicate) in the treatment of diarrhea of non-infectious origin and diarrhea after resection of the large intestine].

Smektit was used for treatment of 24 patients, incl. 10 hospitalized with diarrhoea of a non-infectious etiology (postoperative period, non-adherence to the dietetic regime). Microbiological examination involved only examination of the common flora of the large bowel. In the 10 hospitalized patients the complaints receded very rapidly, after a maximum of three days. In the remaining 14 patients who had resections on account of colorectal carcinoma the diarrhoea was in the majority due to reduction of the large bowel and thus reduction of the resorption area. The condition of ten patients became stabilized and the frequency of bowel movements decreased. In the group of four patients after subtotal colectomy only one patient improved. In three patients smektit administration had no effect. In these patients the cause of frequent bowel movements was the extensive reduction of the large bowel.

Adult↗
PubMed1989

Quinolone antimicrobial agents: adverse effects and bacterial resistance.

Adverse effects, drug-drug interactions and bacterial resistance to the new quinolone antimicrobial agents are reviewed. Clinical adverse effects are reported to occur in 5-10% of patients, and include primarily gastrointestinal disturbances, central nervous system toxicity and rash. Laboratory abnormalities are reported to occur in 5-12% of patients, and include mild reversible elevations of transaminases. Quinolones are not recommended in persons whose bone growth is incomplete or in pregnant or nursing women because cartilage toxicity has been observed in juvenile beagles. Drug-drug interactions may occur between quinolones and theophylline, caffeine, and magnesium- or aluminium-containing compounds such as antacids and sucralfate. Bacterial resistance occurs by chromosomal mutations which alter the target enzyme DNA gyrase or decrease drug accumulation. Emergence of resistance during therapy is uncommon to date but can be problematic in infections with Pseudomonas aeruginosa. Staphylococcus aureus and other bacteria for which the therapeutic index may be low. In summary, quinolones thus far have been well tolerated, but more experience is needed to determine the exact nature and extent of adverse effects and emergence of bacterial resistance.

4-Quinolones↗
PubMed1999

Chitinosans as tableting excipients for modified release delivery systems.

The term 'chitinosans' embraces the spectrum of acetylated poly(N-glucosamines) ranging from chitin to chitosan. Chitinosans (I), at acidic pH, have protonated amines which can interact with oppositely charged drug ions and, thereby, modify drug release from drug delivery systems. Tablets were compressed from a physical mixture containing salicylic acid (II) as the model drug, I, and magnesium stearate. Five commercial I compounds, varying in degree of deacetylation and molecular weight, were selected. Tablets were compressed at 5000, 10 000, and 15 000 psig using a Carver and a single punch tablet press. The differential scanning calorimetry thermograms provided evidence of I-II interaction in the powder blend. Analysis of variance (ANOVA) indicated that the compression pressure did not significantly affect the crushing strength (CS) or the release profile of II from the I-matrix tablets (P?0.05). Furthermore, the ANOVA also indicated that the tablet press used during manufacture did not affect the above properties (P?0.05); however, the chitinosans significantly affected the CS as well as the release profile of II from I-matrix tablets (P<0.05). This study provides further evidence for the use of commercial I compounds as excipients for use in modified release drug delivery systems.

Acetylation↗
PubMed2000

Effect of magnesium tanshinoate B on the production of nitric oxide in endothelial cells.

Nitric oxide (NO) is a potent vasodilator which plays an important role in regulating vascular tones. Danshen, a Chinese herbal medicine has been widely used for the treatment of cardiovascular diseases. The objective of this study was to investigate the effect of magnesium tanshinoate B (MTB), a compound purified from Danshen, on the production of NO in human endothelial cell line (ECV304). After cells were incubated with MTB (1-10 microM) for 1 or 4 h, amounts of NO metabolites released by cells were quantified and cellular NOS activities were determined following the conversion of [3H]arginine to [3H]citrulline. The NOS protein expression was determined by Western immunoblotting analysis. MTB (1-10 microM) stimulated the release of NO and its metabolites from endothelial cells. Following MTB treatment, the cellular NOS activities were significantly enhanced with a concomitant increase in the levels of constitutive NOS (cNOS) protein mass (110-178%). Selective activation of cNOS by MTB may be employed therapeutically in modulating NO production in endothelial cells.

Blotting, Western↗
PubMed2002

Novel therapies in development for the treatment of traumatic brain injury.

In industrialised countries, the mean per capita incidence of traumatic brain injury (TBI) that results in a hospital presentation is 250 per 100,000. In Europe and North America alone, this translates to > 2 million TBI presentations annually. Approximately 25% of these presentations are admitted for hospitalisation. Despite the significance of these figures, there is no single interventional pharmacotherapy that has shown efficacy in the treatment of clinical TBI. This lack of efficacy in clinical trials may be due, in part, to the inherent heterogeneity of the traumatic brain injury population. However, it is the multifactorial nature of secondary injury that also poses a major hurdle, particularly for those therapies that have been designed to specifically target an individual injury factor. It is now becoming increasingly recognised that any successful TBI therapy may have to simultaneously affect multiple injury factors, somewhat analogous to other broad spectrum interventions. Recent efforts in experimental TBI have therefore focussed on developing novel pharmacotherapies that may affect multiple injury factors and thus improve the likelihood of a successful outcome. While a number of interventions are noteworthy in this regard, this review will focus on three novel compounds that show particular promise: magnesium, substance P antagonists and cyclosporin A.

Animals↗
PubMed1987

Acute pesticide poisoning in England and Wales.

Between 1979 and 1983 less than 1% of admissions from acute poisoning in the UK were due to pesticides and fewer than 4% of admissions in those under 5 years were from this cause. Organochlorine, organophosphorus and carbamate insecticides account for only 10% of the total in both children and adults. Suspected pesticide poisoning was the cause of fewer than 0.3% of home accidents in those under 10 years of age and less than 4% of suspected poisonings documented by the Home Accident Surveillance System. Rodenticides were thought to be involved in 62% of these cases. Of children who presented to hospital 42% were admitted and 93% of these were discharged home within 2 days. In the UK, the morbidity from acute pesticide poisoning in children is low and the mortality is nil and there is therefore no evidence to support the view that paediatric pesticide intoxication is a significant clinical problem. Though no fatalities were recorded in children, pesticides were responsible for 1.3% of all deaths due to poisoning in the UK between 1979 and 1983. In adults admitted to hospital, the mortality from pesticide poisoning is approximately 12% and three quarters of these deaths are due to the deliberate ingestion of paraquat. The general term pesticide refers to a group of products that are used as insecticides, acaricides, fungicides, herbicides, rodenticides, and plant growth agents. Chemically, the group includes bipyridilium compounds, carbamates, chloralose, chlorates, coumarins, dinitro compounds, dithiocarbamates, fluoroacetates, organochlorine organophosphorus and organotin compounds, pentachlorophenol, phenoxyacetates, phosphine (as magnesium and aluminium phosphides), pyrethrins, pyrethroids and triazines.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMedDate not supplied

Experimental study of a novel thermotherapy for hepatocellular carcinoma using a magnesium ferrite complex powder that produces heat under a magnetic field.

BACKGROUND/AIMS: The anti-cancerous effect on hepatocellular carcinoma of a newly established form of thermotherapy, which uses an implant heating system, was evaluated. As a new material for application in hyperthermia, the authors developed a powder type Mg-ferrite complex that produces heat under a relatively low-power magnetic field. METHODOLOGY: This material suspended in Lipiodol was injected into tumors on the backs of mice that consisted of human hepatocellular carcinoma cells. Hyperthermia was performed by directing a magnetic charge on tumor-bearing mice that contained the Mg-ferrite complex. The temperature of the tumor was kept at 42-43 degrees C, while the magnetic field power ranged from 50 to 80G. RESULTS: A 10-min hyperthermia treatment was insufficiently effective against tumor growth. Systemic injection of doxorubicin (ADM) before hyperthermia appeared to enhance the anti-cancerous effect, but the difference was little and did not reach a statistically significant level (repeated measure analysis of variance). The anticancerous effect of hyperthermia for 15 minutes, in contrast, was marked. The nodules had almost completely disappeared by the end of the experiment. CONCLUSIONS: In conclusion, it is suggested that hyperthermotherapy using this newly developed Mg-ferrite complex might become an option for low-invasive therapy for advanced hepatocellular carcinoma in humans.

Animals↗