Olfactory nerve projections to the olfactory bulb in rabbit: demonstration by means of a simplified ammoniacal silver degeneration method.
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Animals↗
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Silver(I) carbonyl and silver(I) ethylene complexes of a B-protected fluorinated tris(pyrazolyl)borate ligand.
B-methylated ligand [MeB(3-(C2F5)Pz)3]-enables the isolation of a lithium adduct [MeB(3-(C2F5)Pz)3]Li with fac-N3F3 coordination, and rare isolable silver carbon monoxide and silver ethylene complexes, [MeB(3-(C2F5)Pz)3]AgCO and [MeB(3-(C2F5)Pz)3]AgC2H4.
Boron Compounds↗
[Use of a 3.8 % silver diamine fluoride solution for root canal therapy of infected tooth roots].
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Adult↗
AgCo3PO4(HPO4)2.
The structure of the hydrothermally synthesized compound AgCo3PO4(HPO4)2, silver tricobalt phosphate bis(hydrogen phosphate), consists of edge-sharing CoO6 chains linked together by the phosphate groups and hydrogen bonds. The three-dimensional framework delimits two types of tunnels which accommodate Ag+ cations and OH groups. The title compound is isostructural with the compounds AM3H2(XO4)3 (A = Na or Ag, M = Co or Mn, and X = P or As) of the alluaudite structure type.
Journal Article↗
Cross-linked silver-impregnated skin for burn wound management.
Biological skin is effective in restoring the missing water vapor barrier and promoting healing in burn wounds. Its effectiveness in wound management has been limited, however, by its inherently limited antibacterial properties and the fact that it is sometimes rejected before healing is complete, even reversing previous beneficial effects. Limited availability and storage difficulties have posed further problems. Impregnation of biological skin with silver ions has been proven to provide a potent bactericidal effect directly at the wound surface. We hypothesized that aldehyde cross-linking of silver-impregnated skin would mask the histocompatibility sites from the recipient's immune system. This has been demonstrated previously with aldehyde cross-linking of allografts and xenografts, prolonging retention sufficiently to permit complete wound healing. Commercially available skin was treated with an aldehyde compound and impregnated with silver. Initial studies of this cross-linked skin for treatment of burn wounds showed average retention to be between 117 and 161 days, far exceeding that of any untreated skin. It was subsequently found that the aldehyde cross-linking permitted impregnation with higher concentrations of silver than had previously been possible--2,600 to 2,830 ppm as compared to an average of 1,020 to 1,350 ppm in previously available silver-impregnated skin. This results in a more potent, immediate antibacterial effect at the wound surface and an extended period of time-release antibacterial action before the silver is exhausted. The antibacterial properties of this aldehyde cross-linked silver-impregnated skin are effective in decontaminating even grossly infected wounds and in protecting against contamination of clean wounds from adjacent infected areas or external sources.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Generalized argyrosis in man: neurotological, ultrastructural and X-ray microanalytical findings.
Generalized argyrosis can produce a number of abnormalities, including skin discoloration, liver and kidney dysfunction. We describe a patient with generalized argyrosis following long-term self-treatment with oral silver intake, in whom skin discoloration, progressive taste and smell disorders, vertigo and hypesthesia were observed. These findings were confirmed by chemosensory tests and electrophysiological investigations. The development of hypogeusia was assessed by subjective tests, while the progression of hyposmia was followed by recording olfactory evoked cortical potentials. Light and electron microscopy of tissue samplings demonstrated electron-dense mineral deposits in basal membranes, in macrophages, in the perineurium of peripheral nerves, along elastic and collagenous fibers, and in necrotic cells of the oral submucosa. Silver and sulfur deposits in affected tissues could be defined by X-ray microanalysis. The quantitative ratio between silver and sulfur in involved tissues was similar to that of an inorganic silver-sulfide (Ag2S) standard. The minute increase in the sulfur content when compared to the inorganic standard suggested a sulfur containing organic matrix of the tissue precipitates. Our findings indicate that the affinity of silver for membrane and neuronal structures and the deposition of silver as an insoluble compound (Ag2S) induce the progression of clinical disease.
Ageusia↗
Light microscopical localization of enzymes by means of cerium-based methods. III. Visualization techniques for cerium phosphate.
Cerium-based methods are more and more used for the electron microscopic localization of phosphohydrolases. By means of the earlier described Ce-Pb-technique, it is possible to localize these enzymes on the light microscopical level. The final product of this reaction is lead sulfide. In addition to this technique, other visualization methods for the light microscopically not visible cerium phosphate are proposed. 3 successful techniques are described in the report: The cerium perhydroxide reaction. By means of H2O2 cerium phosphate is converted into cerium perhydroxide which has an orange-yellowish colour. The manganese dioxide reaction with the conversion of cerium phosphate into cerium oxalate, which is able to reduce permanganate into the hardly soluble brown coloured manganese dioxide. A silver technique (Ce-Pb-AgS-method), which is characterized by the conversion of cerium phosphate into lead phosphate and in a second step to lead sulfide. At the active sites of the lead sulfide, the reduction of silver ions takes place. The reduced silver is converted in a final step into silver sulfide. The enzyme activity is represented by a brown or black coloured staining.
Acid Phosphatase↗
In vitro study of remineralization of dentin: effects of ions on mineral induction by decalcified dentin matrix.
We examined the effects of various ions on the mineralization of dentin matrix in vitro. Demineralized dentin matrix was incubated in a metastable calcium phosphate solution with or without silicate, fluoride, calcium, phosphate, magnesium or silver. Insoluble dentin matrix induced mineral formation after incubation for 10.2 h in the metastable solution without added ions. Silicate at 5 microM and fluoride at 40 microM significantly reduced the mineral induction time. At least 200 microM calcium or 100 microM phosphate was required to promote mineral induction. Conversely, magnesium and silver concentrations as low as 10 and 2 microM inhibited mineral induction. The mineral induced by each sample after incubation for 24 h was identified by its X-ray diffraction pattern as apatite. We concluded that silicate is a stronger inducer of remineralization of dentin matrix than fluoride, calcium or phosphate, and that magnesium and silver inhibit the induction of remineralization of dentin matrix.
Animals↗
catena-Poly[1,4-diazoniabicyclo[2.2.2]octane [silver(I)-tri-mu-thiocyanato-kappa6S:S]].
The title compound, [(C6H14N2)[Ag(NCS)3]]n, is a polymeric silver(I) complex. The Ag(I) atom is hexacoordinated by the S atoms of six thiocyanate anions, with each thiocyanate S atom acting in a bridging mode to link the Ag atoms together. The unique Ag(I) atom lies at a cell origin and has crystallographically imposed 3 symmetry. The diazonia[2.2.2]octane molecule lies about a site with 6 imposed symmetry with the unique N atom on a threefold axis. The S and N atoms of the thiocyanate ligands sit on a mirror plane and a threefold axis, respectively. The crystal structure consists of one-dimensional chains, which are stabilized by N-H...N hydrogen bonds to form a three-dimensional network.
Journal Article↗
Flow cytometry as a tool to monitor the disturbance of phagocytosis in the clam Mya arenaria hemocytes following in vitro exposure to heavy metals.
The effectiveness of toxicology biomonitoring programs could be improved by the addition of sensitive biomarkers. In this study the cell viability and sensitivity of phagocytic function of phagocytes from bivalves (Mya arenaria) to selected heavy metals were measured by flow cytometry, a novel approach. Hemocytes (phagocytes) collected from bivalves by puncture of the posterior adductor muscle were incubated in vitro for 18 h in hemolymph containing 10(-9)-10(-3)M of cadmium chloride, zinc chloride, mercuric chloride, methylmercury chloride or silver nitrate, before determining their capacity to phagocytose fluorescent latex beads by flow cytometry. Heterogeneity of the hemocyte cell population was determined by forward scatter (FSC) and side scatter (SSC) cytometric profile which showed two distinct cell populations. At low doses (10(-9), 10(-8) M), all the metal compounds studied stimulated phagocytic activity except silver nitrate. At higher levels of exposure (10(-6), 10(7) M), all metals caused a significant concentration-related decrease in hemocyte phagocytosis activity. From the concentration of each metal inducing 50% suppression (IC50) of the phagocytic activity, the immunotoxic potential of metals with respect to phagocytic function can be ranked in the following increasing order: ZnCl2 < CdCl2 < AgNO3 < HgCl2 < CH3HgCl. Parallel analysis of hemocyte viability showed that suppression of phagocytosis by heavy metals was not solely related to a decreased cell viability. These results reveal the high but different degree of sensitivity of the phagocytosis activity of bivalves with respect to heavy metals, as measured by flow cytometry, and demonstrate that flow cytometry is a potentially useful tool in ecotoxicological monitoring.
Animals↗
Electron microscope characterization of AgBr heterojunctions with silver carboxylates and their influence on the morphology of developed silver particles in thermally developed photomaterials.
Silver halide crystals formed during in situ treatment of silver stearate crystals with various halidizing agents are observed by scanning and transmission electron microscopy to form on the lateral edges of the silver carboxylate crystals. The location of the silver halide phase on the crystal edge is dictated by the anisotropic structure of the silver stearate crystal lattice, specifically, the layered structure in which silver ion layers are separated by long-chain hydrocarbon groups. The formation of AgBr on the lateral faces of these crystals is proposed to be typical not only of the formation of silver halide on silver stearate but also for all silver carboxylates of the general formula [AgCnH2(n-1)O2]2 when the crystals of these silver carboxylates have anisotropic, layered structures. The silver bromide/silver carboxylate heterojunction in an in situ system has been clearly observed by transmission electron microscopy. The heterojunction is comprised of a distorted silver carboxylate lattice, which accommodates the misalignment between the AgBr and [Ag(O2CR)]2 crystal lattices. The nature of heterojunction between the AgBr and the silver carboxylate when the AgBr is prepared separately from the preparation of the silver carboxylate differs from the in situ heterojunction. In this case, a layered compound, proposed to have a Ag1-xNaxSt composition, forms between the AgBr and the silver stearate which is a unique feature of this interface. The differences in the structure of interfaces formed between the silver halide and the silver fatty acid complex result in different silver particle morphologies during thermal development of exposed photothermographic films. The developed silver is generally filamentary when the photothermographic material contains silver halide prepared by the in situ exchange reaction between silver carboxylate and a brominating agent. If the photothermographic material is prepared from previously synthesized silver halide crystals, the preformed AgBr route, the developed silver generally crystallizes as dendritic crystals.
Bromides↗
Synthesis and structural characterization of silver(I), aluminium(III) and cobalt(II) complexes with 4-isopropyltropolone (hinokitiol) showing noteworthy biological activities. Action of silver(I)-oxygen bonding complexes on the antimicrobial activities.
Through two unequivalent oxygen donor atoms of the hinokitiol (Hhino; C10H12O2; 4-isopropyltropolone) ligand that showed noteworthy biological activities, the dimeric, silver(I)-oxygen bonding complex [Ag(hino)]2 1, the monomeric aluminium(III) complex [Al(hino)3].0.5H2O 4 and the cobalt(II) complex "[Co(hino)2]2.H2O" 6 were synthesized and characterized with elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR and solution (1H and 13C) NMR spectroscopy. The crystal structure of 1 was determined by Rietveld analysis based on X-ray powder diffraction (XPD) data and those of [Al(hino)3].MeOH 4a and [Co(hino)2(EtOH)]2 6a, being obtained as yellow block crystals and red platelet crystals, respectively, by crystallization of 4 and 6, were determined by single-crystal X-ray analysis. The antimicrobial activities of 1, 4 and 6, evaluated with minimum inhibitory concentration (MIC; microg ml(-1)), were compared with those of other metal complexes (M=Na, Li, Cs, Ca, V, Zn) with the hino- ligand. The antimicrobial activities observed in the alkali-metal salts strongly suggested that they were attributed to the effect of the anionic hino- species. The antimicrobial activities of 1 were significantly enhanced, whereas those of other metal complexes were suppressed, compared with those of the neutral Hhino and anionic hino- molecules. The antimicrobial activities observed in 1 were comparable with those of other recently found silver(I)-oxygen bonding complexes, the ligands of which had no activity. Thus, it is proposed that the antimicrobial activities of the silver(I)-oxygen bonding complexes are due to a direct interaction or complexation of the silver(I) ion with biological ligands such as protein, enzyme and membrane, and the coordinating ligands of the silver(I) complexes play the role of a carrier of the silver(I) ion to the biological system.
Aluminum↗
Influence of hydrogen bonding on coordination polymer assembly.
An extended dipyridyl ligand (L1) capable of hydrogen bonding with guest species via urea functionalities has been designed and synthesised. Assembly of a silver(I) coordination polymer of L1 is dependent on the nature of the hydrogen bond acceptor in a logical extension of the monopyridyl analogue.
Dimethyl Sulfoxide↗
Glossopharyngeal nerve evoked potentials after stimulation of the posterior part of the tongue in dogs.
OBJECTIVE: Lower cranial nerve palsy is one of the most critical complications after posterior fossa surgery. However, no established monitoring procedures exist for glossopharyngeal nerve function. Therefore, glossopharyngeal nerve evoked potentials after stimulation of the posterior part of the tongue in dogs was studied to analyze whether glossopharyngeal nerve compound action potentials and evoked potentials are useful in the intraoperative monitoring of patients undergoing brainstem and cerebellopontine angle surgery. METHODS: Glossopharyngeal nerve action potentials and cortical potentials were evoked by stimulating the posterior part of the tongue in mongrel dogs. The potentials were evoked by supramaximal constant current electrical stimuli delivered with bipolar stainless steel needle electrodes and recorded with silver ball electrodes. RESULTS: Compound nerve action potentials were recorded from the exposed intracranial portion of the glossopharyngeal nerve. The latency of the initial negative peak of the action potentials was 2.8 +/- 0.6 milliseconds (mean +/- standard deviation; n = 17). Evoked cortical potentials were recorded on the coronal gyrus by stimulating the contralateral side. The latencies of the initial positive peak and negative peak were 20.1 +/- 3.7 and 35.7 +/- 8.2 milliseconds, respectively (n = 6). Ipsilateral tongue stimulation elicited biphasic evoked potentials on the coronal gyrus, which had small amplitudes and delayed latencies. Both compound nerve action potentials and cortical evoked potentials disappeared after sectioning of the glossopharyngeal nerve. CONCLUSION: The glossopharyngeal nerve action potentials and cortical potentials elicited by the stimulation of the posterior one-third of the tongue can be recorded. These evoked potentials represent a new means for intraoperative monitoring of patients undergoing surgery in the brainstem via the cerebellopontine angle, which involves the lower cranial nerves.
Action Potentials↗
Ultraviolet-visible and surface-enhanced Raman scattering spectroscopy studies on self-assembled metalloporphyrin films on organic monolayer-modified ultra-thin silver substrates.
A self-assembled monolayer (SAM) film of 5,10,15,20-tetra-(para-chlorophenyl)-porphyrin terbium (or lutetium) hydroxy compound (TbOH/LuOH) fabricated on a silver substrate premodified with a SAM of 4-mercaptopyridine (PySH) was studied by ultraviolet-visible (UV-Vis) spectroscopy and surface-enhanced Raman scattering (SERS) spectroscopy. PySH can modify the substrate and deliver its pyridyl group pointing out from the silver surface. Thus, we can investigate the effects of the central metals of the metalloporphyrins in the formation of the composite films. For the TbOH-PySH composite film, a new absorption band arising from TbOH appears at 425 nm, and a band at 512 nm due to the PySH-modified silver substrate shifts to a longer wavelength (538 nm). The results suggest that TbOH is successfully assembled on the top of PySH-modified silver film and that there is an interaction between TbOH and PySH in the film. The frequency shifts and relative intensity changes of bands due to PySH in the SERS spectra imply the coordination of the pyridyl group on Tb in the SAM. As for the LuOH-PySH composite film, its SERS spectrum shows bands arising from both the LuOH and PySH moieties, indicating that LuOH is assembled on the PySH-modified silver film. Furthermore, a band at 1221 cm(-1) due to the in-plane C-H bending mode of PySH disappears, implying that the pyridyl moiety of PySH becomes more parallel to the silver surface upon the formation of the LuOH-PySH composite film. Additionally, an absorption band at 515 nm shifts to a longer wavelength (541 nm) and becomes broad upon the formation of the composite film, suggesting an interaction between LuOH and PySH in the film. By comparing the spectral changes between the two self-assembled composite films, we find that the central metal is crucial in the formation of the composite films. The structure and orientation of the composite films depend on the central metal of the metalloporphyrin compounds.
Journal Article↗
Understanding selective enhancement by silver during photocatalytic oxidation.
The superiority of silver deposited titania particles over bare titania particles for the photocatalytic oxidation of selected organic compounds is explained: the presence of silver mainly enhances the photocatalytic oxidation of organic compounds that are predominantly oxidised by holes, while it has only an insignificant effect on those organic compounds that require hydroxyl radicals for their mineralisation.
Journal Article↗
[Effect of HIV antigen glycoproteins and morphine on accompanying reactions of liberating Ag+-sensitive SH-containing nonprotein compounds in the "antigen-antibody" interaction].
The interaction of blood serum immunoglobulins of M, G, and A classes of the donors with monospecific serums (MSS)-anti-IgM, anti-IgG and anti-IgG was established to be associated by Ag(+)-sensitive-SH containing non protein compounds release. This phenomenon formation should be related to a parallel running associated reaction mediated by conformational and/or some other changes of immunoglobulins macrostructure under highly specific intermolecular interaction with adequate MSS in the reactive mixtures. As a rule these processes are associated by the break and reduction of mixed disulphide bounds between thiol containing nonprotein compounds and proteins. HIV antigen glycoproteins and morphine preliminary introduced into the analogic reactive mixtures were found to block this phenomenon. If in these reactive mixtures the serums including three serotypes hepatitis B virus antigen is introduced this phenomenon is preserved. This effect of HIV antigen glycoproteins and morphine could be explained by their direct and/or mediated influence on the immunoglobulins macrostructure. As a result of the latter the immunoglobulins structure-functional status is infringed, being indirectly evidenced by absence of the associated reaction of release Ag(+)-sensitive-SH containing non protein compounds in the reactive mixtures. The processes presented are capable to play an essential role in formation of polyclonal gammapathy under HIV-infection.
Antigen-Antibody Reactions↗
Influences of changes in multitopic tris(pyrazolyl)methane ligand topology on silver(I) supramolecular structures.
The reactions between silver tetrafluoroborate and the ligands 1,2,4,5-C(6)H(2)[CH(2)OCH(2)C(pz)(3)](4) (L1, pz = pyrazolyl ring), o-C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2) (L2), and m-C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2) (L3) yield coordination polymers of the formula (C(6)H(6)(-)(n)[CH(2)OCH(2)C(pz)(3)](n)(AgBF4)(m))( infinity ) (n = 4, m = 2, 1; n = 2, ortho substitution, m = 1, 2; meta substitution, m = 2, 3). In the solid state, L2 molecules dimerize by a pair of C-H.pi interactions, forming an arrangement that resembles the tetratopic ligand L1. In the solid-state structure of 1, each silver atom is kappa(2)-bonded to two tris(pyrazolyl)methane units from different ligands with the overall structure a polymer made up from 32-atom macrocyclic rings formed by bonding tris(pyrazolyl)methane groups from nonadjacent positions on the central arene rings to the same two silver atoms. In 2, each silver is bonded to two tris(pyrazolyl)methane units in the same kappa(2)-kappa(2) fashion as with 1, forming a polymer chain. The chains are organized into dimeric units by strong face-to-face pi-pi stacking between the central arene rings making bitopic L2 act as half of tetratopic L1. The chains in both structures are organized by weak C-H.F hydrogen bonds and pi-pi stacking interactions into very similar 3D supramolecular architectures. The structure of 3 contains three types of silvers with the overall 3D supramolecular sinusoidal structure comprised of 32-atom macrocycles. Infrared studies confirm the importance of the noncovalent interactions. Calculations at the DFT (B3LYP/6-31G) level of theory have been carried out on L2 and also support C-H.pi interactions. Electrospray mass spectral data collected from acetone or acetonitrile show the presence of aggregated species such as [(L)Ag(2)(BF(4))](+) and [(L)Ag(2)](2+), despite the fact that (1)H NMR spectra of all compounds show that acetonitrile completely displaces the ligand whereas acetone does not.
Crystallography, X-Ray↗