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At least 415 records · Page 23Linked to original sources
PubMed1996

Obstructive sialadenitis caused by intraparotid deposits of gold salts: a case report.

A case of obstructive sialadenitis caused by deposits of gold salt compound in the intraparotid lymphoid tissues in a woman with classic rheumatoid arthritis is presented. The patient had been treated with a parenteral gold salt compound (sodium aurothiomalate) for 10 years with chrysotherapy balance of 7525 mg. She presented with swelling of both parotid glands on eating, and computed tomography images showed accumulation of high density spots. Obstructive sialadenitis most probably was caused by local compression on the excretory ducts of the parotids. This clinical disorder should be classified as a case of mechanical, nontumoral, obstructive sialadenitis caused by gold salt compound.

Adult↗
PubMed2006

Secondary interactions in gold(I) complexes with thione ligands. 5. Two ionic compounds of the form bis(thione)gold(I) bis(4-halobenzenesulfonyl)amide.

Bis(1,3-thiazolidine-2-thione-kappaS2)gold(I) bis(4-chlorobenzenesulfonyl)amide, [Au(C3H5NS2)2](C12H8Cl2NS2O4), has no imposed symmetry. Classical N-H...N and N-H...O hydrogen bonds link the residues to form chains parallel to the b axis. Weaker interactions involve C-H...O, C-H...Au and a number of X...Cl contacts (X = Cl, S or Au) clustered in the region y approximately equal to 1/4}. In bis(1-methylimidazolidine-2-thione-kappaS2)gold(I) bis(4-iodobenzenesulfonyl)amide, [Au(C4H8N2S)2](C12H8I2NS2O4), the Au atom of the cation and the N atom of the anion lie on the twofold axis (0, y, 1/4}) in the space group C2/c. The formula unit forms a self-contained ring with two symmetry-equivalent N-H...O hydrogen bonds, and weak C-H...X (X = O, I or S), Au...I and I...I contacts are observed. In both compounds, the anions display extended conformations.

Journal Article↗
PubMed1991

Substrate specificity and activation mechanisms of collagenase from human rheumatoid synovium.

Substrate specificity studies of collagenase extracted from human rheumatoid synovium suggest that synovial pannus tissue overlying articular cartilage may not be particularly active in degradation of cartilage type II collagen, which, considering the poor inherent healing capacity of the articular hyaline cartilage, may exert a protective function against inadvertant tissue damage. Rheumatoid synovial tissue was also used to establish synovial fibroblast cell lines. Treatment of these cells in monolayer cultures with IL-1 leads to collagenase gene activation, increased collagenase production and an almost complete autoactivation of secreted collagenase. Interleukin-1 also activated stromelysin gene suggesting this as a possible mechanism effecting autoactivation. Latent human fibroblast and macrophage collagenase purified from culture medium were efficiently activated by phenylmercuric chloride but also by gold thioglucose, gold sodium thiomalate and HCIO. These new observations support the Cys73 switch activation mechanism. In contrast to neutrophil collagenase, the activation by gold(I) compounds and HCIO was associated with a change in the apparent molecular weight of the fibroblast procollagenase. In addition, gold(I) compounds rendered collagenase more susceptible to thermal denaturation. Thus the fibroblast-type interstitial collagenase, probably derived from fibroblast- and macrophage-like synoviocytes, seems to provide the predominant collagenolytic potential in human rheumatoid synovial tissue. Furthermore, the conditions in synovitis tissue may be such as to favor at least initial activation of collagenase synthesized and secreted in situ.

Arthritis, Rheumatoid↗
PubMed1994

Electron microscopy of cytochrome c oxidase crystals: labeling of subunit III with a monomaleimide undecagold cluster compound.

Two-dimensional crystals of beef heart mitochondrial cytochrome c oxidase dimers were labeled at Cys-115 of subunit III with a monomaleimide derivative of an undecagold cluster compound. The binding site of the gold cluster compound and hence the site of subunit III were identified by image processing of cryoelectron micrographs of the crystals preserved in a mixture of glucose and uranyl acetate. The shape of the cytochrome oxidase dimer can be approximated as a parallelogram which is 44 by 82 A with an included angle of 80 degrees oriented with its long dimension along the a axis of the crystal. Labeling of subunit III was confirmed by a shift in the mobility of approximately 50% of subunit III molecules upon electrophoresis in polyacrylamide gels in the presence of sodium dodecyl sulfate. Averaged images of undecagold cluster labeled crystals and of unlabeled crystals were calculated; each image represents an average of approximately 17,000 molecules of either labeled or unlabeled cytochrome oxidase. On the basis of a statistical analysis of the differences between the two images, the gold cluster binds along a line 30 degrees from the a axis and 29 A from the center of the dimer. This result is interpreted in the context of other structural studies including the site of cytochrome c binding which Frey and Murray found to be near the a axis and 18 A from the center of the dimer [Frey, T. G., & Murray, J. M. (1994) J. Mol. Biol. 237, 275-297].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Gold(III) complexes with bipyridyl ligands: solution chemistry, cytotoxicity, and DNA binding properties.

Gold(III) compounds generally exhibit significant cytotoxic effects on cancer cell lines and are of potential interest as antitumor drugs. We report here on the solution chemistry, the cytotoxicity, and the DNA binding properties of two new bipyridyl gold(III) compounds: [Au(bipy)(OH)(2)][PF(6)] (1) and the organometallic compound [Au(bipy(c)-H)(OH)][PF(6)] (2) (bipy(c) = 6-(1,1-dimethylbenzyl)-2,2'-bipyridine). Both compounds are sufficiently soluble, and stable for hours, within a physiological buffer at 37 degrees C; [Au(bipy)(OH)(2)][PF(6)], at variance with [Au(bipy(c)-H)(OH)][PF(6)], is quickly and quantitatively reduced by ascorbate. Both compounds showed relevant cytotoxic effects toward the A2780S, A2780R, and SKOV3 tumor cell lines; lower effects were detected on the CCRF-CEM/S and CCRF-CEM/R lines. In most cases the mechanisms of resistance to CDDP are only marginally effective against these gold(III) complexes. The interactions of [Au(bipy)(OH)(2)][PF(6)] and [Au(bipy(c)-H)(OH)][PF(6)] with calf thymus DNA were investigated in vitro by various techniques to establish whether DNA represents a primary target for these compounds. Addition of saturating amounts of DNA did not affect appreciably the visible spectra of these gold(III) complexes. Some slight modifications of the CD spectra of calf thymus DNA and of the DNA melting parameters were observed; in any case, ultrafiltration experiments showed that binding of these gold(III) complexes to DNA is weak and reversible. The mechanistic implications of these findings are discussed.

2,2'-Dipyridyl↗
PubMed2000

Analysis of antiphotobleaching reagents for use with FluoroNanogold in correlative microscopy.

Correlative microscopy is an important approach for bridging the resolution gap between fluorescence and electron microscopy. We have employed FluoroNanogold (FNG) as the detection system in these types of studies. This immunoprobe consists of a gold cluster compound to which a fluorochrome-labeled antibody is covalently linked. In these preparations, the fluorescence signal from FNG is first recorded then the gold cluster compound is subjected to a silver enhancement reaction before examination by electron microscopy. Potential complications are those associated with photochemical reactions that occur during fluorescence microscopy. We have evaluated this and some anti-photobleaching agents (i.e., 1,4-diazabicyclo[2.2.2]octane [DABCO],p-phenylenediamine [PPD], and N-propyl gallate [NPG]) for their utility with FNG in correlative microscopy. When DABCO was employed, the gold signal from FNG was dramatically diminished but the fluorescence signal was unaffected. The gold signal of DABCO-treated samples decreased to approximately 30% of that of the other samples. On the other hand, PPD and NPG did not adversely affect the FNG labeling. We recommend that either PPD or NPG be used and that DABCO be avoided as an antiphotobleaching reagent for this technique.

Frozen Sections↗
PubMedDate not supplied

Studies of the intestinal metabolism of oral gold.

In order to understand some of the unique toxic/therapeutic properties of the orally administered gold containing compound auranofin, the intestinal metabolism of gold was studied in 4 normal subjects. A triple lumen intestinal perfusion apparatus was used to measure intestinal flux using a non-absorbable radiolabelled marker dilution technique. Over a short (50 cm) segment of proximal small bowel, substantial disappearance of gold was observed; the findings, however, were most consistent with a loose, reversible adsorption onto the enteric cell surface rather than true trans-mucosal absorption. There was no evidence for an entero-hepatic recirculation of gold in these subjects or in 4 additional patients with rheumatoid arthritis studied in a similar manner.

Administration, Oral↗
PubMed2004

Inhibition of lysosomal cysteine proteases by chrysotherapeutic compounds: a possible mechanism for the antiarthritic activity of Au(I).

Although Au(I) complexes have been used to treat rheumatoid arthritis for over 75 years, their mechanism of action is still poorly understood. A family of enzymes responsible for joint destruction in rheumatoid arthritis, the cathepsins, has been discussed as a possible biological target of Au(I). In this study, inhibition of the cathepsins by known Au(I) drugs and related compounds was investigated. The compounds tested inhibited cathepsin activity with IC50 values as low as 600 nM. More typical IC50 values were in the 50-200 microM range. Although the gold complexes are not extremely potent cathepsin inhibitors, it is likely that this inhibition is biologically relevant given the high concentrations of Au(I) in the serum and joints of patients undergoing chrysotherapy. While it is likely that there are multiple targets of Au(I) in vivo, inhibition of the cathepsins would provide protection against the joint destruction that is a hallmark of rheumatoid arthritis and is one possible mechanism for Au(I) antiarthritic activity.

Animals↗
PubMed2004

Complexes of dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], with formylferrocene thiosemicarbazones: synthesis, structure and cytotoxicity.

Dichloro[2-(dimethylaminomethyl)phenyl- phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], reacts with the formylferrocene thiosemicarbazones derived from 4-methyl-, 4-phenyl-, 4-ethyl- and 4,4-dimethyl-3-thiosemicarbazides, HFcTSC, to give complexes of general formula [Au(Hdamp-1C)Cl(FcTSC)]Cl. These complexes were isolated and characterized by elemental analysis, mass spectrometry and IR, 1H NMR and (13)C NMR spectroscopy. In some cases, cyclic voltammetric studies were carried out and these showed that the complexation of gold affects the redox behaviour of the ferrocene unit. The in vitro antitumor activity against the HeLa cell line was also determined for the more soluble complexes. The IC(50) values were found to be higher than that of cisplatin but the maximum antiproliferative activity was similar.

Antineoplastic Agents↗
PubMed2004

Synthesis of gold nanoparticles from an organometallic compound in supercritical carbon dioxide.

This article presents the synthesis of gold nanoparticles in a single-phase supercritical fluid carbon dioxide solvent. The gold nanoparticles were formed by the reduction of triphenylphosphine gold(I) perfluorooctanoate with dimethylamineborane. Transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy reveal the formation of gold nanoparticles of 1 nm in diameter. A high dispersion stability of the gold nanoparticles in supercritical carbon dioxide can be obtained by binding both triphenylphosphine and fluorocarbon ligands on the surface of the gold nanoparticles.

Letter↗
PubMed2005

Removal of As(III) and As(V) from water using a natural Fe and Mn enriched sample.

The arsenic removal capacity of a natural oxide sample consisting basically of Mn-minerals (birnessite, cryptomelane, todorokite), and Fe-oxides (goethite, hematite), collected in the Iron Quadrangle mineral province in Minas Gerais, Brazil, has been investigated. As-spiked tap water and an As-rich mining effluent with As-concentrations from 100 microg L(-1) to 100 mg L(-1) were used for the experiments. Sorbent fractions of different particle sizes (<38 microm to 0.5 mm), including spherical material (diameter 2 mm), have been used. Batch and column experiments (pH values of 3.0, 5.5, and 8.5 for batch, and about pH 7.0 for column) demonstrated the high adsorption capacity of the material, with the sorption of As(III) being higher than that of As(V). At pH 3.0, the maximum uptake for As(V) and for As(III)-treated materials were 8.5 and 14.7 mg g(-1), respectively. The Mn-minerals promoted the oxidation of As(III) to As(V), for both sorbed and dissolved As-species. Column experiments with the cFeMn-c sample for an initial As-concentration of 100 microg L(-1) demonstrated a very efficient elimination of As(III), since the drinking water limit of 10 microg L(-1) was exceeded only after 7400 BV total throughput. The As-release from the loaded samples was below the limit established by the toxicity characteristic leaching procedure, thus making the spent material suitable for discharge in landfill deposits.

Adsorption↗
PubMed1989

Immunological alterations inducible by mercury compounds. II. HgCl2 and gold sodium thiomalate enhance serum IgE and IgG concentrations in susceptible mouse strains.

We determined the levels of total IgE, IgG and IgM in the sera of HgCl2 and gold sodium thiomalate (GST) treated A.SW, C57Bl/6, and DBA/2 mice. In HgCl2 treated A.SW mice, IgE and IgG levels increased up to 30 times above normal. In C57Bl/6 mice HgCl2 induced a slight IgE increase, but no change in IgG. Strain DBA/2, by contrast, did not show significant increases in either IgE or IgG. A.SW mice also proved susceptible to the immunostimulatory effects of GST in that they responded by significant increases in IgE, IgG, and IgM. C57Bl/6 mice responded to GST by an increase in IgM alone, and DBA/2 mice again, were resistant. The same strain-specific responses have been reported with respect to the autoimmunizing effects inducible by HgCl2 and GST.

Adjuvants, Immunologic↗