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PubMed2002

Di-mu-sulfido-bis[diaqua(18-crown-6)barium(II)]-saccharin (1/2).

The molecule of the title compound [systematic name: di-mu-sulfido-bis[diaqua(1,4,7,10,13,16-hexaoxacyclooctadecane-kappa(6)O)barium(II)] bis[1,2-benzisothiazol-3(2H)-one 1,1-dioxide]], [Ba(2)S(2)(C(12)H(24)O(6))(2)(H(2)O)(4)](C(7)H(5)NO(3)S)(2), lies on an inversion centre. The Ba(II) atom encapsulated by the 18-crown-6 ring is coordinated by the six O atoms of the crown, two water O atoms and two bridging S atoms. The four-membered ring composed of the Ba(II) atoms and the bridging S atoms makes a dihedral angle of 67.1 (1) degrees with the crown-ether ring. The aromatic ring system of the saccharin moiety is essentially planar. The packing is built up from layers of the molecules and is stabilized by three intermolecular O-H.O hydrogen bonds.

Journal Article↗
PubMed1998

Synthesis and Characterization of Two New Copper Tellurites, Ba(2)Cu(4)Te(4)O(11)Cl(4) and BaCu(2)Te(2)O(6)Cl(2), in Supercritical H(2)O.

Two new compounds containing tellurite building blocks coordinated to copper and barium atoms have been isolated from hydrothermal solvents. A new layered compound, Ba(2)Cu(4)Te(4)O(11)Cl(4) (I), has been obtained by reacting BaCl(2).2H(2)O, CuO, and Te(OH)(6) in NH(4)Cl solution at 375 degrees C for 4 days. Green, platelike crystals of I crystallize in the centrosymmetric space group, P&onemacr;, with a = 9.275(2) Å, b = 12.135(2) Å, c = 9.263(2) Å, alpha = 98.23(3) degrees, beta = 108.35(3) degrees, gamma = 110.90(3) degrees, and Z = 2. The compound contains two types of layers, one based on copper oxides linked by Te(4)O(11) groups, and the other based on Cu(2)Cl(4) units. The tellurium atoms adopt the common TeO(3+1) units or TeO(3) pyramids, and the oxygen-coordinated copper atoms adopt a square planar CuO(4) arrangement. Dark green, prismatic crystals of BaCu(2)Te(2)O(6)Cl(2) (II) were obtained by reacting BaCl(2).2H(2)O, Cu(2)O, and Te(OH)(6) in NH(4)Cl solution at 375 degrees C for 18 h. Compound II was refined in the acentric monoclinic space group, P2(1) (a = 7.434(2) Å, b = 7.448(2) Å, c = 8.271(2) Å, beta = 97.42(3) degrees, Z = 2), and is based on Te(2)O(6) units connected by copper atoms or copper chloride groups. As in I, tellurium atoms are contained within TeO(3+1) or TeO(3) units and the connecting copper atoms are nearly square planar. The chloride-coordinated copper atoms group adopt a square pyramidal CuO(3)Cl(2) geometry with a chlorine atom occupying the apical position. The formal oxidation states of the copper atoms in compound I are distributed such that the connecting atoms in an oxide environment are 2+ and atoms within a chloride environment are 1+, whereas in compound II, all copper atoms are 2+. Bond valence sums for both compounds and magnetic susceptibility data for I support these assignments. The optical band gap for I was determined by diffuse reflectance spectroscopy and indicate that it is a wide band gap material (E(g)() = 3.00 eV).

Journal Article↗
PubMed2004

Synthesis, characterization, and electronic structure of Ba5In4Bi5: an acentric and one-electron deficient phase.

The new ternary phase Ba(5)In(4)Bi(5) was synthesized by direct reaction of the corresponding elements at high temperature. It crystallizes in a noncentrosymmetric space group and represents a new structure type (tetragonal, P4nc with a=10.620(2) and c=9.009(2) A, Z=2). The structure is built of interconnected heteroatomic clusters of In(4)Bi(5), square pyramids with In(4)-bases and four exo-bonded bismuth atoms (bond to the In atoms). According to Wade's rule the compound is electron-deficient with one electron per cluster, that is, [In(4)Bi(5)](10-) instead of the expected [In(4)Bi(5)](11-) for a closed-shell species. The clusters are discussed also in light of the known heteroatomic deltahedral clusters with the same composition but different charge, [In(4)Bi(5)](3-). Band structure calculations on the new compound suggest substantial participation of barium in the overall bonding of the structure that "accounts" for the electron shortage

Journal Article↗
PubMed1981

Opiate effects on rabbit vagus nerve: electrophysiology and radioligand binding.

Intracellular recordings were made from rabbit nodose ganglion cells in vitro. Morphine (up to 100 micro M), normorphine (up to 10 micro M) and D-Ala2, Leu5-enkephalin (DADLE) (up to 5 micro M) each had no detectable effect on the electrical properties of the cell membrane, except for local anesthetic-like actions at the highest concentrations which were not reversed by naloxone. Extracellular recordings were made from the infranodose vagus nerve in vitro using a sucrose gap method. No effects of morphine, normorphine or DADLE were detected on the resting potential, compound action potential or compound action potential enhanced by barium or tetraethylammonium. Moderate levels of stereospecific binding of tritiated dihydromorphine and DADLE were detected in both the nodose ganglion and vagus nerve. It is surmised that the radioligand binding sites on the nodose ganglion and vagus nerve are not functionally linked to detectable electrophysiological effects.

Action Potentials↗
PubMed1986

Pre- and postsynaptic actions of noradrenaline and clonidine on myenteric neurons.

alpha-2 adrenergic agonists inhibit nicotinic excitatory postsynaptic potentials and reduce calcium dependent action potentials in myenteric neurons. To test the hypothesis that adrenergic inhibitory effects on action potential configuration and on inhibition of acetylcholine release from the nerve terminal are analogous processes, the pharmacological characteristics and underlying mechanisms of these two effects were compared in neurons of the myenteric plexus in the guinea pig. Both clonidine and noradrenaline reduced the nicotinic fast excitatory postsynaptic potential in a concentration dependent manner, although the maximum effect produced by noradrenaline was greater. The specific alpha-2 antagonist RX781094 blocked the action of noradrenaline, with an apparent Kd value of 3.8 +/- 1 nM. Clonidine was similarly antagonized by low concentrations of this compound. The potassium channel blocker barium prevented inhibition of the fast excitatory postsynaptic potential by clonidine but not by noradrenaline. Action potentials recorded from after-hyperpolarization neurons with cesium chloride filled electrodes were prolonged in duration due to the blockade by cesium of outward potassium movement. Under these conditions, noradrenaline reduced action potential duration and slowed the rate of rise of the calcium dependent component in the presence of tetrodotoxin. RX781094 antagonized the latter effect with an estimated apparent Kd of 5.8 +/- nM. The rate of rise of the calcium dependent action potential was not affected by clonidine (30 nM to 1 microM). In the absence of potassium channel blockers noradrenaline caused hyperpolarizations which were blocked by RX781094. It has been previously shown that clonidine hyperpolarizes myenteric neurons via an adrenergically mediated increase in potassium conductance. It was concluded that the characteristics of presynaptic inhibition of release by noradrenaline and clonidine parallel the respective actions of these agonists on action potential configuration. While all clonidine effects could be explained on the basis of an increase in potassium conductance, noradrenaline exerted an additional inhibitory action which persisted in the presence of potassium channel blockade by barium or cesium.

Action Potentials↗
PubMed1988

[Total and segmental colonic transit times. Measurements by radio-opaque markers].

Measurement of the transit time by addition of a marker to the natural alimentary bolus permits an overall evaluation of colonic motricity. Bismuth and barium salts, dyes and radioactive compounds have been used, each of these methods having its own drawbacks, such as insufficient or impossible quantification, influence on transit or partial intestinal absorption. Radio-opaque pellets do not modify transit, are not absorbed, provide quantification readily and measure transit selectively in the ascending colon, the descending colon, the sigmoid colon and the rectum. The progression of pellets is followed by radiography of the abdomen. The number of radiograms can be reduced to 3 or even 1 by graded administration of the pellets over 3 consecutive days. The results obtained in normal subjects are similar in different studies; they are not influenced by age or by the amount of fibrous material present in food. Total and right segmental transit times are longer in women than in men. Measurement of the colonic transit time is indicated in severe constipation to differentiate between colonic inertia and terminal obstruction which have different mechanisms and treatments. Such measurements are also useful for an objective evaluation of constipation.

Colon↗
PubMed1984

Cisapride accelerates gastric emptying and mouth-to-caecum transit of a barium meal.

Cisapride (R 51 619) is a newly synthesized compound, which facilitates the release of acetylcholine in the myenteric plexus of the gut. Its effect on gastric emptying of a barium meal was evaluated in 84 patients under randomized, double-blind conditions. Two oral doses (5 mg and 10 mg) of cisapride were compared with a placebo, and two intravenous doses (4 mg and 8 mg) with a placebo and with 10 mg metoclopramide. All doses of cisapride and metoclopramide were significantly superior to placebo in accelerating gastric emptying, intensifying antral contractions and shortening the mouth-to-caecum transit time. The effects of 8 mg cisapride and 10 mg metoclopramide given intravenously were comparable.

Adolescent↗
PubMed2003

Interaction of inhalational anaesthetics with CO2 absorbents.

We review the currently available carbon dioxide absorbents: sodium hydroxide lime (=soda lime), barium hydroxide lime, potassium-hydroxide-free soda lime, calcium hydroxide lime and non-caustic lime. In general, all of these carbon dioxide absorbents are liable to react with inhalational anaesthetics. However, there is a decreasing reactivity of the different absorbents with inhalational anaesthetics: barium hydroxide lime >> soda lime > potassium-hydroxide-free soda lime > calcium hydroxide lime and non-caustic lime. Gaseous compounds generated by the reaction of the anaesthetics with desiccated absorbents are those that threaten patients. All measures are comprehensively described to--as far as possible--prevent any accidental drying out of the absorbent. Whether or not compound A, a gaseous compound formed by the reaction of sevoflurane with normally hydrated absorbents, is still a matter of concern is discussed. Even after very high loading with this compound, during long-lasting low-flow sevoflurane anaesthesias, no clinical or laboratory signs of renal impairment were observed in any of the surgical patients. Finally, guidelines for the judicious use of different absorbents are given.

Absorption↗
PubMed2005

In vitro antimicrobial activity of Fill Canal, Sealapex, Mineral Trioxide Aggregate, Portland cement and EndoRez.

AIM: To determine in vitro the antimicrobial activity of Fill Canal, Sealapex, Mineral Trioxide Aggregate (MTA), Portland cement and EndoRez on various species of microorganisms. METHODOLOGY: The diffusion method on Müller-Hinton agar (MH) was employed. A base layer was made using MH agar and five wells were made by removing agar at equidistant points. Sealers were placed into the wells immediately after manipulation. The microorganisms Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10231 were seeded by pour plate. The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. Aliquots of 10 mL of 0.05% triphenyltetrazolium chloride gel were added for optimization and the zones of inhibition were measured. RESULTS: Sealapex and Fill Canal demonstrated antimicrobial activity for all strains. For MTA and Portland cement, only E. coli was not inhibited. No antimicrobial activity was detected for EndoRez. CONCLUSIONS: In this laboratory study, Fill Canal, Sealapex, MTA and Portland cement presented antimicrobial activity whilst EndoRez did not.

Aluminum Compounds↗
PubMed1976

Conformationally restricted analogs of histamine H1 receptor antagonists: trans and cis-1-benzyl-3-dimethylamino-6-phenylpiperidine.

The syntheses of trans- and cis-1-benzyl-3-dimethylamino-6-phenylpiperidine (1 and 2) are described. Compounds 1 and 2 were found to be inhibitors to histamine, acetylcholine, and barium chloride induced contractions of the isolated guinea pig ileum. Compounds 1 and 2 do not exhibit appreciable stereoselectivity in their ability to inhibit smooth muscle contractions. The cis compound 2 is a more effective inhibitor of histamine N-methyltransferase than the trans isomer 1.

Acetylcholine↗
PubMed1997

[Various reactions of sevoflurane with the individual components of soda lime].

The various components of commercial soda lime (sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide) were studied in terms of their reactivity with sevoflurane at its boiling point (59 degrees C). A simple closed system, a reflux cooler, served as a model. Analyses were performed by GC/MS. Besides sevoflurane, we identified four compounds: A, B, C, and D. Free methanol, formaldehyde and formic acid could not be found. Presumably methanol is transferred from an intermediate formalin-semiacetal of the hexafluorisopropanol. Calcium hydroxide and barium hydroxide showed little reaction with sevoflurane, whereas larger amounts of reaction products were observed with sodium hydroxide and potassium hydroxide. The alkali hydroxides of sodalime are presumably responsible for its reaction with halogenated inhalation anaesthetics. We therefore conclude that decomposing reactions of halogenated inhalation anesthetics with dry soda lime could be prevented by using a newly developed soda lime.

Anesthetics, Inhalation↗
PubMed1990

Ground water and oil field waste sites: a study in Vermilion Parish.

Water samples were obtained from 128 private water wells surrounding eight oil field waste sites in Vermilion Parish. The specimens were analyzed for five heavy metals: barium, arsenic, chromium, lead, and cadmium. Half of the specimens were then analyzed for 16 volatile organic compounds. A blood sample was obtained from healthy adults drinking water from the wells tested for volatile organic compounds and this blood sample was also analyzed for volatile organic compounds. None of the water samples had levels of heavy metals or volatile organic compounds that exceeded the National Primary Drinking Water Standards. Barium levels in excess of 250 parts per billion suggested that styrene, toluene, and chloroform might be present. Blood levels of volatile organic compounds were significantly higher than could be accounted for by water consumption with levels in smokers significantly higher than in nonsmokers. These data suggest that as yet there is no contamination of ground water supplies around these sites. Volatile organic accumulation in humans probably occurs from a respiratory rather than from an oral route.

Humans↗
PubMed1984

Unusual histological appearances of barium sulphate--a case report with scanning electron microscopy and energy dispersive x ray analysis.

Multiple birefringent rhomboidal crystals seen on histological examination of a resected oesophagus were subsequently found to contain elemental barium and sulphur on energy dispersive x ray ( EDX ) analysis. Scanning electron microscopy and EDX analysis of readily available commercial barium sulphate suspensions suggested that the two forms of barium sulphate previously described in tissue sections may be a result of the method of preparation of the commercial suspension used. With increased use of barium sulphate prepared by crushing the natural compound, birefringent rhomboidal crystals should be found with increasing frequency in endoscopic biopsy samples and resected specimens.

Barium Sulfate↗
PubMed2003

An ordered low-temperature phase of barium nitroprusside trihydrate studied by neutron diffraction.

Crystals of barium pentacyanonitrosylferrate trihydrate (barium nitroprusside trihydrate), Ba[Fe(CN)(5)(NO)].3H(2)O, have been studied by neutron diffraction in order to examine the structural behaviour of the compound in the 20-120 K temperature range and to determine the structure at 105 K. The results show the existence of a new crystal phase of the compound at 80 K (with a duplicated a parameter), which still exists at 20 K. The crystal structure at 105 K shows a rearrangement of the water molecules, which results in an ordered structure with P1 symmetry. Two of the four independent nitroprusside cations are rotated by 4.5 degrees around the [100] direction.

Barium Compounds↗
PubMed2001

Ba4Si3Br2: a double salt of barium bromide and barium silicide containing a novel cyclotrisilicide unit.

A new compound of the composition Ba4Si3Br2 was obtained by reacting BaSi with a melt of BaBr2. Ba4Si3Br2 may be described as a double salt between a Zintl phase and a halide. The structure was determined by single-crystal X-ray diffraction (P21c, a= 1504.1(2), b = 884.5(1), c = 880.2(1) pm, beta = 101.93(2) degrees, R = 0.041 Rw = 0.079). The crystal structure contains isolated barium cations and bromide anions as well as novel singly bonded cyclotrisilicid units. The electronic structure has been studied by linear Muffin tin orbital (LMTO) band structure calculations, which reveal semiconducting behavior with a band gap of about 0.1 eV, and by an analysis of the electron localization function.

Journal Article↗
PubMed2002

A ternary complex of aqua(18-crown-6)bis(o-nitrophenolato)barium(II), the triaqua(18-crown-6)(o-nitrophenolato)barium(II) cation and the o-nitrophenolate anion.

In the title compound [systematic name: triaqua(1,4,7,10,13,16-hexaoxacyclooctadecane-kappa(6)O)(2-nitrophenolato-kappaO)barium(II)-aqua(1,4,7,10,13,16-hexaoxacyclooctadecane-kappa(6)O)bis(2-nitrophenolato-kappa(2)O,O')barium(II)-2-nitrophenolate (1/1/1)], [Ba(C(12)H(24)O(6))(C(6)H(4)NO(3))(H(2)O)(3)][Ba(C(12)H(24)O(6))(C(6)H(4)NO(3))(2)(H(2)O)](C(6)H(4)NO(3)), the two Ba(II) atoms encapsulated by the 18-crown-6 rings have different coordinations. Although both Ba(II) atoms are coordinated to the six O atoms of the crowns, in the neutral moiety, the Ba(II) atom is coordinated to one terminal O atom from a water molecule, two phenolate O atoms and two nitro-group O atoms, while in the cationic moiety, the Ba(II) atom is coordinated to three terminal O atoms from water molecules and one phenolate O atom. Both the crowns are eclipsed and translated along the b direction. In the asymmetric unit, the three components are interconnected by four O-H.O interactions. The packing is stabilized by two intermolecular C-H.O interactions and by one O-H.O interaction.

Journal Article↗
PubMed2000

A novel barium-sensitive calcium influx into rat astrocytes at low external potassium.

Cultured rat cerebellar astrocytes, loaded with the Ca2+-sensitive fluorescent dyes Fura-2 or Fluo-3, responded with cytoplasmic Ca2+ transients, when the external K+ concentration was reduced from 5 mM to below 1 mM. Ca2+ transients were generated after changing to a saline containing 0.2 mM K+ in 82% of the cells (n =303) with a delay of up to 4 min. Cultured rat cortical neurones, which responded in high-K+ saline (50 mM) with Ca2+ transients, showed no Ca2+ responses in low K+ (n =22). In acute rat hippocampal brain slices, presumed glial cells responded with Ca2+ transients in low K+ similar to astrocytes in culture (88%, n =17). The Ca2+ transients were observed both in somatic and dendritic regions of cultured astrocytes, as examined with confocal laser scanning microscopy. Patch-clamped astrocytes hyperpolarized in 0.2 mM K+ from an average resting potential of -65 +/- 4 mV to -98 +/- 20 mV (n =15). The Ca2+ transients in low K+ were suppressed in Ca2+-free saline, buffered with 0.5 mM EGTA, but not after depletion of intracellular Ca2+ stores by thapsigargin, cyclopiazonic acid or by Ruthenium Red, indicating that they were due to Ca2+ influx into the cells, and not caused by intracellular Ca2+ release. The addition of different divalent cations revealed that Ba2+, but not Ni2+, Cd2+, Sr2+ or Mg2+, reversibly blocked the Ca2+ transients in low K+. There was a significant reduction of the Ca2+ responses at micromolar Ba2+ concentrations (Ki = 3.8 microM). The application of different K+ channel blockers, tetraethylammonium, dequalinium, tolbutamide, clotrimazole, or quinidine had no effect on the Ca2+ responses. Removal of external Na+, or intracellular acidification by the addition of 40 mM propionate to the saline, had also no influence on the generation of the Ca2+ transients. The results suggest that reducing the external K+ concentration elicits a Ca2+ influx into rat astrocytes which is highly sensitive to Ba2+. It is discussed that this Ca2+ influx might occur through K+ inward rectifier channels, which become Ca2+-permeable when the extracellular K+ concentration decreases to 1 mM or below.

Aniline Compounds↗
PubMed2002

Barium(II)-2,4-dinitrophenolate-18-crown-6 at 183 K.

The title compound, bis(2,4-dinitrophenolato-kappa2O,O')(1,4,7,10,13,16-hexaoxadecane-kappa6O)barium(II), [Ba(C6H3N2O5)2(C12H24O6)], is a 1:1 complex of barium(II)-2,4-dinitrophenolate and 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic beta angle of the P2(1)/n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C-H...O interactions.

Journal Article↗