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Results for “Organosilicon Compounds”

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At least 19 recordsLinked to original sources
PubMed1988

Genotoxicity studies on selected organosilicon compounds: in vivo assays.

Six organosilicon compounds which had been found to have clastogenic activity in an in vitro battery of genotoxicity assays were evaluated in rat bone marrow cytogenetic assays for assessing clastogenicity in an in vivo system. None of the six compounds produced significant increases in chromosome aberrations in the rodent assay. However, trimethylsilanol produced a single value at the high-dose level/48-hr sampling interval that was significantly elevated when compared to the low concurrent control value. Both an independent repeat of the bone marrow cytogenetic assay and performance of the rat dominant lethal test failed to substantiate the presence of any significant clastogenic activity. Organosilicon compounds involved in the synthesis and degradation of polydimethylsiloxanes were not genotoxic in the in vivo clastogenicity tests employed in these studies.

Animals↗
PubMed1988

Genotoxicity studies on selected organosilicon compounds: in vitro assays.

A series of 12 organosilicon compounds representing potential intermediates in the synthesis and degradation of polydimethylsiloxanes were evaluated for genotoxic potential with a battery of in vitro assays. Microbial assays included the Ames bacterial reverse mutation in Salmonella, mitotic gene conversion in Saccharomyces cerevisiae D4 and DNA repair in E. Coli pol A +/-. These assays were conducted with and without a metabolic activation system containing Aroclor 1254-induced rat-liver homogenate. Forward gene mutation, sister-chromatid exchange, DNA alkaline elution and chromosome aberration potential were evaluated in mouse lymphoma L5178Y tissue culture cells. The tissue culture assays were performed with and without metabolic activation mixture utilizing uninduced mouse-liver S-9. The use of this enzyme preparation was felt to more closely mimic the actual in vivo situation and to be more compatible with mouse cells employed in the assay. No evidence of gene mutation was observed. However, six of the 12 compounds evaluated demonstrated potential in vitro clastogenic (chromosome damaging) activity.

Animals↗
PubMed1992

Kinetic resolution of organosilicon compounds by stereoselective dehydrogenation with horse liver alcohol dehydrogenase.

Stereoselective dehydrogenation of three isomers of trimethylsilylpropanol was carried out with horse liver alcohol dehydrogenase (HLADH, EC 1.1.1.1.) and optically active organosilicon compounds were obtained in a water-organic solvent two-layer system with coenzyme regeneration. Furthermore, we examined the effects of the silicon atom on stereoselectivity of HLADH compared to the corresponding carbon compounds. Substitution of the silicon atom for the carbon atom was found to improve the stereoselectivity of HLADH. For example, the optical purity of the remaining 1-trimethylsilyl-2-propanol was higher than 99% enantiomeric excess (ee) at 50% conversion, whereas that of the carbon analogue was 84% ee. This phenomenon was probably ascribable to the bulkiness of the organosilicon compounds derived from their longer Si-C bond. Kinetic analysis in an aqueous monolayer system demonstrated that the specific properties of the silicon atom greatly affected the reactivity of these substrate compounds.

1-Propanol↗
PubMed1977

[Effect of some organosilicon compounds (silatranes) on the biosynthesis of collagen in cartilagenous tissue of chick embryo].

Effect of some organosilicon compounds from the class of silatranes on the biosynthesis of collagen in cartilagenous tissue of chick embryos in vitro was studied. The criteria for assessing the intensity of collagen biosynthesis was the formation of peptide bond 14C-hydroxyproline from 14C-proline of incubation medium. All the compounds studied (methylsilatrane, ethoxysilatrane and chloromethylsilatrane) stimulated total protein biosynthesis and collagen biosynthesis in cartilagenous tissue of chick embryos. The most pronounced stimulation of the biosynthesis of collagen was observed at 3-10(-3) M concentration of silatranes within 180 min. of incubation (14C-proline was added to the incubation medium 60 min after the beginning of the incubation). The activity of partly purified collagen prolyl-hydroxylase in the presence of silatranes was also studied.

Animals↗
PubMed1988

Effects of an organosilicon compound on the tubular apparatus of rat kidney. A histological and enzyme histochemical report.

Male adult Wistar rats were treated for 8 weeks with an organosilicone [2,2-dimethyl-4-(chloromethyl)-1,3-dioxa-2-silacyclopentane] employing two different dosages (25 and 50 mg/kg body weight i.p. daily) and the changes in the tubular apparatus of the kidney were investigated employing histological and enzyme-histochemical methods. The effects, more pronounced at the higher dosage, were the following: The brush borders of the proximal tubules were stuck together and disintegrated; only few epithelial cells remained intact showing a decreased activity of nonspecific esterases and the increase of beta-hydroxybutyric acid dehydrogenase. The nuclei of most of the epithelial cells in the distal tubules were dislocated towards the enlarged lumen and the cytoplasma showed a decrease of nonspecific esterases and an increase of beta-hydroxybutyric acid dehydrogenase. The collagen fibers in the walls of the collecting tubules were dislocated and disintegrated with a discontinuous border of Mg2+-ATPase; the nuclei of the epithelial cells were pyknotic, the cytoplasma showed an increase of beta-hydroxybutyric acid dehydrogenase. The induced changes were partially reversible after a recovery period of 8 weeks.

Animals↗
PubMed1987

Hypocholesterolemic action of 1-ethoxysilatrane.

Intraperitoneal administration of the organosilicon compound 1-ethoxysilatrane to the rat caused a 25% decrease in the concentration of cholesterol in serum without affecting that of triacylglycerols. The specific activity of 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis, was depressed in hepatic microsomes of silatrane-treated animals.

Animals↗
PubMed1988

A comparison of the rates of methylation of mercury(II) species in aquatic media by various organotin and organosilicon moieties.

Metals can be methylated in environmental aqueous media by a variety of organotin and organosilicon compounds. Main group metals and metalloids were surveyed for the identification of species that can either donate or accept methyl groups. The methylation of mercury(II) by trimethyltin cation was found to be a bimolecular reaction, the reaction rate of which decreased with increasing chloride concentration. Kinetic investigations using NMR techniques showed that the most important pairs of reactants were (CH3)3Sn+ + HgCl2, (CH3)3SnCl + HgCl2, and (CH3)3SnCl + HgCl-3. Sodium 2,2,3,3-tetradeutero-3-(trimethylsilyl)propionate (TSP) and sodium 2,2-dimethyl-2-silapentane-5-sulfonate (DSS) were found to methylate mercury(II). Organylsilatranes were found to transfer their organic groups readily to mercury(II) to produce organomercury compounds.

Magnetic Resonance Spectroscopy↗
PubMedDate not supplied

[Atranes: their ulcerostatic effect and its possible mechanisms].

The ulcerostatic activity of methylethyl (sylathrane-1-ilmethyl) sulfoiodide, 1-(chlormethyl) sylatrane, and 1-(isopropoxy)hermatrane has been revealed at experimental acetate ulcer in rats. The effect of atranes was equal to that of oxyferriscorbone and exceeded that of methyluracil. All the compounds studied inhibited peroxide oxidation of lipids in blood and stomach tissues from ulcer and in model experiments in egg yolk liposomes. The processes of ulcer development and photodynamic effects of lipid peroxidation in biological objects have been summarized. The data obtained allow to conclude that the ulcerostatic mechanism of action effect of atranes and the comparable drugs is based on their antioxidative effect.

Acetates↗
PubMed1978

Prostatic carcinoma treated with 2,6-cis-diphenylhexamethylcyclotetrasiloxane (Cisobitan).

Thirteen patients with stage III or IV carcinoma of the prostate were treated with 2,6-cis-Diphenylhexamethylcyclotetrasiloxane (Cisobitan, a new organosilicon compound. The drug proved to be a strong antiandrogen and exerted all the known effects of estrogens, including feminization and cardiovascular complications. It is therefore doubtful whether Cisobitan will be a reasonable alternative to estrogens in the treatment of patients with advanced prostatic cancer.

Aged↗
PubMedDate not supplied

[Dopaminergic component in the mechanism of action of gamma-aminobutyric acid derivatives and structural analogs].

In experiments on rats and male mice the GABA derivatives fenibut, fepiron and the organosilicon compound N-methyl (3-trimethylsilil)pyrrolidone (IA) antagonized apomorphine sterotypy and aggressiveness. Fenibut and IA potentiated haloperidol catalepsy. Fenibut, fepiron, sodium hydroxybutyrate and IA also antagonized the effects of phenamine. The biochemical investigations have shown that fenibut and IA produce acceleration of the intraneuronal synthesis and catabolism of DA. It is suggested that the behavioral effects of the GABA derivatives are partly relative to inhibition of the dopamin--ergic system.

Amphetamine↗
PubMed1990

[Possible mechanisms of anti-ulcer action of silatranes].

A stimulating effect of methylethyl(silatrane-I-ilmethyl)-sulphonium iodides, 1-(ethoxy)silatranes and 1-(chloromethyl)silatrane on the processes of rat test acetate ulcer healing is studied. Silatranes efficiency is not inferior to oxyferriscorbone and exceeds that of methacil. It is shown that all preparations inhibit the processes of lipids peroxidation in the blood, in liposomes and stomach tissue.

2,3-Diketogulonic Acid↗
PubMedDate not supplied

[Changes in the periodontium in prolonged hypodynamia and the use of biphosphanates and silatrane for the purpose of their prevention].

Forty-day hypodynamia caused by "hanging" rats on a special stand with discontinuance of the status function of the hind limbs and partial maintenance of the supporting function of the front limbs led to progressive atrophic changes in the alveolar process of the animals' jaws, which were accompanied by changes of the mineral phase manifested by diminished parameter of microfirmness. Atrophy of the alveolar process in hypodynamia was attended by marked tissue changes in the form of dentogingival pockets, widening of the periodontal fissure, and intensified resorption of the interradicular and interalveolar septa of the molars.

Animals↗
PubMedDate not supplied

[1-Ethoxysilatrane: ulcerostatic effect and its possible mechanisms].

Stimulating effect of I-ethoxy silatrane on healing of acetate derived stomach ulcer was studied in rats. The drug was shown to inhibit lipid peroxidation and free-radical oxidation in blood and gastric tissues as well as to accelerate reparation in ulcerous zone. I-Ethoxy silatrane interacted with artificial membranes and affected the respiration rate in liver mitochondria. Membranetropic effect of I-ethoxy silatrane appears to be involved in the drug ulcerostatic effect.

Animals↗
PubMed1990

Investigations on the mechanism of the hypocholesterolemic action of 1-ethoxysilatrane.

Intraperitoneal administration of the nontoxic silicon compound, 1-ethoxysilatrane, to the rat did not cause proliferation of hepatic mitochondria or of endoplasmic reticulum, nor did it affect mitochondrial oxidative phosphorylation. The activities of cholesterol 7 alpha-hydroxylase in hepatic microsomes and of cholesterol oxidase in mitochondria respectively were unaffected by silatrane treatment. The rate of release of bile, whose composition remained unchanged, also was not increased in silatrane-treated animals. The results indicated that the compound did not affect the pathway of cholesterol degradation. A progressive decrease in the activity of hepatic microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase was observed on administration of the compound over a period of three weeks. Consistent with this, cholesterol biosynthesis in liver as measured by incorporation of radioactive precursors, acetate and water but not mevalonate, was significantly decreased in silatrane-treated animals. However, enzyme-linked immunosorbent assay revealed that the concentration of HMGCoA reductase protein was not decreased by the treatment indicating that inactivated enzyme was also present in such microsomes. Addition of silatrane to microsomes in the assay system did not cause inhibition indicating that the inactivation is by an indirect mechanism. It is concluded that the hypocholesterolemic action of the compound rested entirely on the inhibition of cholesterol biosynthesis in vivo by inactivation of the rate-limiting enzyme HMGCoA reductase.

AMP-Activated Protein Kinases↗