Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sodium Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2006

Assessment of genotoxicity of 14 chemical agents used in dental practice: ability to induce chromosome aberrations in Syrian hamster embryo cells.

To assess the genotoxicity of 14 chemical agents used as locally applied agents in dental practice, the ability of these agents to elicit chromosome aberrations was examined using Syrian hamster embryo (SHE) cells. Chromosome aberrations in SHE cells were induced by treatment with three of eight chemical agents used as endodontic medicaments, i.e. ethylenediaminetetraacetic acid (EDTA), formocresol (a mixture of formalin and tricresol), and sodium arsenite. The other five chemical agents, i.e. chloramphenicol, p-chlorophenol, p-phenolsulfonic acid, sodium hypochlorite, and tetracycline hydrochloride exhibited a negative response for chromosome aberrations. Assessment of three dyes used for disclosing dental plaque showed chromosome aberrations induced by basic fuchsin but not by acid fuchsin and erythrosine B. Three local anesthetics, lidocaine hydrochloride, prilocaine hydrochloride, and procaine hydrochloride, were negative for chromosome aberrations. Among the ten chemical agents that exhibited a negative response in the assay, p-chlorophenol, sodium hypochlorite, and erythrosine B induced chromosome aberrations in SHE cells when treated in the presence of exogenous metabolic activation. The percentages of cells with polyploidy or endoreduplication were enhanced by formocresol, sodium arsenite, p-chlorophenol, p-phenolsulfonic acid, sodium hypochlorite, erythrosine B, prilocaine hydrochloride, and procaine hydrochloride in the absence or presence of exogenous metabolic activation. Our results indicate that the chemical agents that had a positive response in the present study are potentially genotoxic to mammalian cells.

Anesthetics↗
PubMed2006

The role of structured water in the calibration and interpretation of theoretical IR spectra.

The purpose of this study was to simulate theoretical infrared (IR) spectra of halogenated acetate salts using density functional theory (DFT), and to calibrate those results with high-resolution ATR-FTIR spectra. Two types of spectra were calculated: one of the solutes solvated in water droplets ranging in size from 15 to approximately 28 H(2)O molecules, and the other of a solvent molecule in equivalently sized (16-29 H(2)O molecules) droplets. The background-subtracted spectra, composed of solvated (halo)acetate spectra minus calculated solvent spectra, were compared with their experimental counterparts. Changes in the calculated IR spectra were used to determine the effects of dissolved salts on the structure of water. Calibrations of model dissolved salt spectra with observation were good; correlations of >0.90 were observed for all haloacetate species.

Acetates↗
PubMed2006

The effect of ionic strength on the UV-vis spectrum of congo red in aqueous solution.

The major peak near 498 nm in the ultraviolet-visible spectrum of congo red in aqueous solution shifts toward the blue while the molar absorptivity of this peak decreases predictably with increasing ionic strength. The shift was observed for solutions in which ionic strength was varied from 0.0 to 1.8M using the uni-univalent ionic compounds, NaCl, NaClO(4), KNO(3) and KBr separately. A plot of the log of the absorbance at the peak versus ionic strength was linear as well as a plot of the log of the wavelength of the major peak (shifted from 498 nm) versus the ionic strength. The slopes of each of these plots were somewhat different depending on the ionic compound.

Bromides↗
PubMed1989

Purification and properties of the intact P-700 and Fx-containing Photosystem I core protein.

The intact Photosystem I core protein, containing the psaA and psaB polypeptides, and electron transfer components P-700 through FX, was isolated from cyanobacterial and higher plant Photosystem I complexes with chaotropic agents followed by sucrose density ultracentrifugation. The concentrations of NaClO4, NaSCN, NaI, NaBr or urea required for the functional removal of the 8.9 kDa, FA/FB polypeptide was shown to be inversely related to the strength of the chaotrope. The Photosystem I core protein, which was purified to homogeniety, contains 4 mol of acid-labile sulfide and has the following properties: (i) the FX-containing core consists of the 82 and 83 kDa reaction center polypeptides but is totally devoid of the low-molecular-mass polypeptides; (ii) methyl viologen and other bipyridilium dyes have the ability to accept electrons directly from FX; (iii) the difference spectrum of FX from 400 to 900 nm is characteristic of an iron-sulfur cluster; (iv) the midpoint potential of FX, determined optically at room temperature, is 60 mV more positive than in the control; (v) there is indication by ESR spectroscopy of low-temperature heterogeneity within FX; and (vi) the heterogeneity is seen by optical spectroscopy as inefficiency in low-temperature electron flow to FX. The constraints imposed by the amount of non-heme iron and labile sulfide in the Photosystem I core protein, the cysteine content of the psaA and psaB polypeptides, and the stoichiometry of high-molecular-mass polypeptides, cause us to re-examine the possibility that FX is a [4Fe-4S] rather than a [2Fe-2S] cluster ligated by homologous cysteine residues on the psaA and psaB heterodimer.

Bromides↗
PubMed2001

Temperature and halide dependence of the photocycle of halorhodopsin from Natronobacterium pharaonis.

The photocycle kinetics of halorhodopsin from Natronobacterium pharaonis (pHR(575)) was analyzed at different temperatures and chloride concentrations as well as various halides. Over the whole range of modified parameters the kinetics can be adequately modeled with six apparent rate constants. Assuming a model in which the observed rates are assigned to irreversible transitions of a single relaxation chain, six kinetically distinguishable states (P(1-6)) are discernible that are formed from four chromophore states (spectral archetypes S(j): K(570), L(N)(520), O(600), pHR'(575)). Whereas P(1) coincides with K(570) (S(1)), both P(2) and P(3) have identical spectra resembling L(520) (S(2)), thus representing a true spectral silent transition between them. P(4) constitutes a fast temperature-dependent equilibrium between the chromophore states S(2) and S(3) (L(520) and O(600), respectively). The subsequent equilibrium (P(5)) of the same spectral archetypes is only moderately temperature dependent but shows sensitivity toward the type of anion and the chloride concentration. Therefore, S(2) and S(3) occurring in P(4) as well as in P(5) have to be distinguished and are assigned to L(520)<--> O(1)(600) and O(2)(600)<--> N(520) equilibrium, respectively. It is proposed that P(4) and P(5) represent the anion release and uptake steps. Based on the experimental data affinities of the halide binding sites are estimated.

Anions↗
PubMed2000

Sucrose tricarboxylate by sonocatalysed TEMPO-mediated oxidation.

Oxidation of sucrose by the NaOCl/TEMPO system provided sucrose tricarboxylate without the addition of sodium bromide as co-catalyst when high-frequency (500 kHz) ultrasound was applied, in contrast to very limited conversion without sonication. In the presence of sodium bromide, sonication also caused acceleration of the oxidation. The rate increase due to sonication of the oxidant system prior to sucrose addition suggests that ultrasound acts at the level of the formation of the nitrosonium ion, the active oxidising species in the catalytic cycle.

Antioxidants↗
PubMed1996

Presynaptic modulation by VIP, secretin and isoproterenol of somatostatin release from enriched enteric synaptosomes: role of cAMP.

The release of somatostatin-like immunoreactivity was studied in isolated synaptosomes. A significant release of somatostatin-like immunoreactivity was observed in the presence of vasoactive intestinal polypeptide (VIP) (10(-6) M: 53.0 +/- 12.4 pg/mg, basal: 14.3 +/- 1.7 pg/mg, n = 5, P < 0.05), secretin (10(-6) M: 56.1 +/- 3.8 pg/mg, basal: 25.8 +/- 1.6 pg/mg, n = 6, P < 0.01) and isoproterenol (10(-5) M: 54.0 +/- 13.4 pg/mg, basal: 20.0 +/- 3.4 pg/mg, n = 8, P < 0.05). Forskolin, an unspecified activator of the adenylate cyclase, caused a significant release of somatostatin-like immunoreactivity (10(-6) M: 57.3 +/- 13.2 pg/mg, basal: 30.0 +/- 5.8 pg/mg, n = 13, P < 0.01) which was further augmented in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX 10(-4) M) (77.0 +/- 17.8 pg/mg, n = 13, P < 0.01). 3-Isobutyl-l-methylxanthine and N6, 2'-O-dibutyryladenosine-3',5'-cyclic monophosphate mimicked at effect of forskolin and VIP. The release of somatostatin was paralleled by an increase of cAMP immunoreactivity in the presence of VIP (10(-6) M: 37.1 +/- 9.4 pmol/mg, basal: 19.8 +/- 4.2 pmol/mg, n = 10, P < 0.05), isoproterenol (10(-5) M: 42.4 +/- 9.8 pmol/mg basal: 16.7 +/- 2.4 pmol/mg, n = 12, P < 0.01) and forskolin (10(-6) M: 47.1 +/- 12.4 pmol/mg, basal: 19.8 +/- 4.2 pmol/mg, n = 10, P < 0.01). The effect of nitric oxide (NO) which acts as an inhibitory neurotransmitter in the enteric nervous system was studied. NO is known to activate guanylate cyclase to induce transmitter release. The NO-generating compound sodium nitroprusside and bromoguanosine-3',5'-cyclic monophosphate (8-Br-cGMP) had no effect on the release of somatostatin-like immunoreactivity. These data demonstrate the stimulatory effect of VIP, secretin and isoproterenol on release of somatostatin-like immunoreactivity from enteric synaptosomes, which is presumably mediated by cAMP-dependent mechanisms. cGMP-dependent mechanisms seem to be of minor relevance.

Adrenergic beta-Agonists↗
PubMed1997

Transmembrane topology of the Rieske Fe/S protein of the cytochrome b6/f complex from spinach chloroplasts.

The topology of the Rieske protein of the cytochrome b6/f complex in thylakoids from spinach chloroplasts was examined by protease protection experiments as well as polypeptide extraction assays using solutions of chaotropic salts or alkaline pH. While neither thermolysin nor trypsin cleave any of the Rieske protein when added to the stromal side of the thylakoid membrane, proteinase K is capable of removing approximately four residues from its NH2-terminus. The protein is resistant to membrane extraction by 0.1 M Na2CO3 or 2 M NaBr but is quantitatively released by 0.1 M NaOH. Treatment of thylakoids with 2 M NaSCN leads to extraction of variable amounts of the protein, depending on the presence or absence of sucrose in the medium which apparently stabilizes the cytochrome complex. From these results we conclude that the Rieske protein is an integral component of the cytochrome complex which spans the thylakoid membrane with a single hydrophobic segment and is anchored predominantly by electrostatic interactions.

Blotting, Western↗
PubMed1999

Nitric oxide inhibits proliferation of human endothelial cells via a mechanism independent of cGMP.

Endothelial cell-derived nitric oxide (NO) has been suggested to inhibit smooth muscle cell proliferation, resulting in the reduction of intimal hyperplasia during atherogenesis. The present study investigates the role of NO from exogenous and endogenous sources on the proliferation of human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (CAEC). Three different NO-generating compounds [sodium nitroprusside (SNP), S-nitroso-glutathione (GSNO) and S-nitroso-acetylpenicillamine (SNAP)] were found to inhibit endothelial cell proliferation measured with three independent methods (cell counting, [3H]thymidine incorporation, DNA histograms) with significant inhibition occurring at concentrations > or = 100 microM. Growth-inhibiting effects were observed after long-term treatment (18-96 h) as well as after short stimulation with NO donors (10 min with a subsequent NO donor-free culture period of 18 h) and were comparable in culture medium (20% serum, growth factor supplementation) and serum-deficient medium (1% serum). The NO donor effects were mediated by the release of NO as they were prevented by NO scavenging. Superoxide dismutase (SOD) was found not to interfere with these effects suggesting that peroxynitrite formation was unlikely to be involved. 1H-[l,2,4]Oxadiazolo[4,3,-alpha]quinoxalin-1-one (ODQ), a specific inhibitor of the soluble guanylate cyclase, was observed not to alter the antiproliferative effects of NO donors although it completely prevented NO-mediated increase of cyclic guanosine 3',5'-monophosphate (cGMP), suggesting that the NO-induced growth inhibition was not mediated by cGMP. Furthermore, inhibition of endogenous NO production by N-nitro-L-arginine methylester (L-NAME) did not affect endothelial cell growth regardless of using serum plus growth factor supplement, growth factor supplement alone, or thrombin to stimulate proliferation. We suggest that constitutively synthesized NO may not regulate endothelial cell proliferation whereas the growth-inhibiting NO effects may occur when an inducible NO synthase associated with a persistently high NO production is expressed in the atherosclerotic vessel wall.

Analysis of Variance↗
PubMed2001

Qualitative detection of selenium in fortified soil and water samples by a paper chromatographic-carboxyl esterase enzyme inhibition technique.

Thevetia peruviana seed carboxyl esterase was employed as a biosensor for the detection of selenium compounds by an enzyme inhibition technique on paper chromatograms. The selenium compounds (sodium selenite and selenium dioxide) appeared as white spots on a magenta background due to the inhibition of Thevetia peruviana seed carboxyl esterase (substrate 1-naphthyl acetate, coupling reagent Fast blue B salt). The minimum detectable amounts were about 5 microg of sodium selenite and 5 microg of selenium dioxide. Many other animal and plant carboxyl esterases gave no inhibition spot under the same conditions. Soil and water samples were fortified with sodium selenite and selenium dioxide. A procedure for preparing test solutions and conditions for paper chromatography was established.

Apocynaceae↗
PubMed2003

Study of the degradation of dyes by MnP of Phanerochaete chrysosporium produced in a fixed-bed bioreactor.

The production of ligninolytic enzymes by the fungus Phanerochaete chrysosporium in a fixed-bed tubular bioreactor, filled with cubes of nylon sponge, operating in semi-solid-state conditions, was studied. Maximum individual manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of 1293 and 225 U/l were detected. The in vitro decolourisation of two structurally different dyes (Poly R-478, crystal violet) by the extracellular liquid obtained in the above-mentioned bioreactor was monitored in order to determine its degrading capability. The concentration of some compounds (sodium malonate, manganese sulphate) from the reaction mixture was optimised in order to maximise the decolourisation levels. A percentage of Poly R-478 decolourisation of 24% after 15 min of dye incubation was achieved. On the other hand, a methodology for a long treatment of these dyes based on the continuous addition of MnP enzyme and H(2)O(2) was developed. Moreover, this enzymatic treatment was compared with a photochemical decolourisation process. The former allowed to maintain the degradation rate almost constant for a long time, resulting in a decolourisation percentage of 70% and 30% for crystal violet and Poly R-478, respectively, after 2 h of treatment. As for the latter, it was not able to degrade Poly R-478, whereas crystal violet reached a degradation of 40% in 2 h.

Anthraquinones↗
PubMed2000

Effects of sildenafil on cAMP and cGMP levels in isolated human cavernous and cardiac tissue.

OBJECTIVES: To further investigate the mechanism of action of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase 5 (PDE5), that has been proved to be effective in the treatment of male erectile dysfunction. We assessed the effects of sildenafil on the in vitro formation of cGMP and cyclic adenosine monophosphate (cAMP) in isolated human corpus cavernosum and cardiac muscle. METHODS: Isolated segments of human corpus cavernosum and cardiac muscle were exposed to increasing concentrations of sildenafil. The dose-dependent accumulation of cGMP and cAMP was determined in the tissue samples by means of radioimmunoassays. Responses of the isolated tissue preparations to sildenafil were compared with those obtained with the reference compounds sodium nitroprusside, forskolin, and milrinone. RESULTS: In the concentration range 0.01 to 1 microM, there was only a minor effect of sildenafil on cGMP levels in isolated human cavernous and cardiac tissues. In contrast, sildenafil was found to increase cAMP significantly in both cavernous and cardiac tissue in physiologic and supraphysiologic concentrations. The stimulation of cAMP by sildenafil was more pronounced in cavernous than in cardiac tissue. Concentrations of cGMP in the cardiac strips were unaltered by milrinone; cAMP was stimulated starting at a concentration of 0.05 microM. In the range of 0.1 to 1.0 microM, the in vitro effect of sildenafil on cAMP levels in the cardiac samples was almost equivalent to that of milrinone. CONCLUSIONS: Our findings provide a potential mechanism for the cardiovascular side effects that have been reported with sildenafil use, highlighting the fact that a "cross-talk" between cGMP and cAMP-dependent signal transduction pathways might exist in human cavernous and cardiac muscle that may be of pharmacologic significance.

Colforsin↗
PubMed2004

Phosphate glasses for tissue engineering: Part 2. Processing and characterisation of a ternary-based P2O5-CaO-Na2O glass fibre system.

This paper presents the results of a study of the thermal properties, solubility and dimensions of a range of phosphate-based glass fibres (PB-GFs). The glass compositions were limited by fixing the P2O5 content to 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40. PB-GFs were obtained from the 50 and 55 mol% P2O5 compositions; however, we were unable to obtain fibres from the 45 mol% compositions. This was linked to the cross-linked density, network connectivity and average chain length of the compositions studied. With regards to thermal parameters investigated, initial data showed an increase of the Tg and crystallisation temperatures with increasing CaO mol% at each fixed phosphate content. A decrease in Tg temperatures was also observed with increasing P2O5 content to 55 mol%. The crystallisation temperatures obtained for compositions with fixed phosphate at 55 mol%, showed a reverse pattern, with a decrease in values as compared to the fixed 50 mol% phosphate compositions. The diameters of the fibres all decreased with increasing RPMs as expected, and the solubility also increased with increasing RPMs. This was related to the increased surface area of the higher RPM fibres. There was also a decrease seen in solubility with increasing CaO mol%.

Biocompatible Materials↗
PubMed1996

Cholinergic-nitrergic interactions in the guinea-pig gastric fundus.

The influence of nitric oxide (NO) on the spontaneous tone and on the contractile responses to electrical field stimulation or to exogenous acetylcholine (ACh) was studied. Circular strips from the guinea-pig gastric fundus were used. The NO-releasing compound sodium nitroprusside reduced the spontaneous tone while the NO-synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) increased it. The L-NAME-induced increase of the tone was antagonized by atropine or indomethacin, suggesting the involvement of cholinergic and prostaglandinergic pathways in this effect. L-NAME significantly potentiated the ACh (10(-8) to 10(-5) M)-induced contractions. L-NAME concentration-dependently potentiated the cholinergic contractions evoked by electrical field stimulation without affecting [3H]ACh overflow from [3H]choline-treated tissues. It is concluded that electrical field stimulation of gastric fundus muscle induces the release of endogenous nitrate which, in turn, functionally antagonizes cholinergic neurotransmission.

Acetylcholine↗
PubMed1991

Changes of ATPase activities in erythrocytes of rats with hypothalamic obesity.

Na,K- and Ca,Mg-ATPase activities in the membrane of red blood cells (RBC) were determined in glutamate treated obese rats (GOR). Both activities are related oppositely. In the obese rats the Na,K-ATPase is higher but the efficiency in maintenance of Na/K-ion concentration gradients is diminished. Ca,Mg-ATPase is decreased in GOR. Under the hypermetabolic condition of cold adaption the Na,K-ATPase activity decreases and the Ca,Mg-ATPase activity rises in both animal groups. The Na,K-ATPase activity in RBC-membranes is positively related to fat accumulation and age.

Animals↗
PubMed1996

Selenium deficiency and thyroid fibrosis. A key role for macrophages and transforming growth factor beta (TGF-beta).

Free radical damage and fibrosis caused by selenium deficiency are thought to be involved in the pathogenesis of myxoedematous cretinism. So far, no pathway explains the link between selenium deficiency and tissue fibrosis. Pharmacological doses of iodine induce necrosis in iodine-deficient thyroids. Necrosis is much increased if the glands are also selenium-deficient, which then evolve to fibrosis. This rat model was reproduced to explore the role of selenium deficiency in defective tissue repair. At first, proliferation indexes of epithelial cells and fibroblasts were comparable between selenium-deficient and control groups. Then, in selenium-deficient thyroids the inflammatory reaction was more marked being mainly composed of macrophages. The proliferation index of the epithelial cells decreased, while that of the fibroblasts increased. These thyroids evolved to fibrosis. TGF-beta immunostaining was prominent in the macrophages of selenium-deficient rats. Anti TGF-beta antibodies restored the proliferation indexes, and blocked the evolution to fibrosis. In selenium deficiency, an active fibrotic process occurs in the thyroid, in which the inflammatory reaction and an excess of TGF-beta play a key role.

Animals↗
PubMed1998

Functional coupling of nitric oxide synthase and soluble guanylyl cyclase in controlling catecholamine secretion from bovine chromaffin cells.

This study was designed to evaluate whether the enzymes of the nitric oxide/cyclic-GMP pathway, nitric oxide synthase and soluble guanylyl cyclase, are functionally coupled in controlling catecholamine secretion in primary cultures of bovine chromaffin cells. In immunocytochemical studies, 80-85% of the tyrosine hydroxylase-positive chromaffin cells also possessed phenylethanolamine-N-methyltransferase, f1p4cating their capability to synthesize epinephrine. Immunoreactivity for neuronal-type nitric oxide synthase was found in over 90% of all chromaffin cells. Reverse transcription-polymerase chain reaction also demonstrated neuronal-type nitric oxide synthase messenger RNA. Immunoreactivity for soluble guanylyl cyclase was detectable in over 95% of chromaffin cells. Double-labeling immunofluorescence studies co-localized neuronal-type nitric oxide synthase and soluble guanylyl cyclase with tyrosine hydroxylase and phenylethanolamine-N-methyltransferase in the majority of chromaffin cells. Chromaffin cells possessed basal nitric oxide synthase activity which could be stimulated by acetylcholine and inhibited by NG-nitro-L-arginine methyl ester. Activation of soluble guanylyl cyclase by endogenously synthesized nitric oxide or the nitric oxide donor compound sodium nitroprusside was blocked by the inhibitor of soluble guanylyl cyclase 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. Catecholamine release and the increase in cytosolic Ca2+ concentration evoked by acetylcholine were enhanced by inhibitors of the endogenous nitric oxide/cyclic-GMP pathway such as NG-nitro-L-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and the protein kinase G inhibitor Rp-8-pCPT-cGMPS. These data indicate that chromaffin cells possess an autocrine nitric oxide/cyclic-GMP pathway tonically controlling the inhibition of catecholamine release.

Adrenal Glands↗
PubMedDate not supplied

Nitric oxide affects LTP in area CA1 and CA3 of hippocampus in low-level lead-exposed rat.

Neonatal Wistar rats were exposed to lead from parturition to weaning via the milk of dams drinking 0.2% lead acetate solution. The alterations in EPSPs in areas CA1 and CA3 of hippocampal slices of 60-day-old adult rats following developmental lead exposure were studied. The results demonstrate that lead exposure in neonatal rats causes a decrease in LTP in area CA1 and an increase in LTP in area CA3. The effects of exposure to NO-generating compound sodium nitroprusside (SNP) on LTP in areas CA1 and CA3 of control and lead-exposed rats were also tested. The data demonstrate that NO causes an increase in LTP in area CA1 and no different alterations in area CA3 of lead-exposed rats. The results also demonstrate that NO may be a messenger molecule in areas CA1 and CA3. It suggests that lead might selectively interfere with specific neurochemical pathways in the hippocampus.

Animals↗