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PubMed1980

Evaluation of a technique alloy for use in teaching intracoronal cast gold procedures.

The instability of the gold market has not diminished the position of the intracoronal cast gold restoration as the treatment of choice in certain clinical situations. While cast gold inlay and onlay techniques will probably remain part of the dental school curriculum, the cost factor in teaching these procedures at the preclinical level can be minimized by using a less expensive technique alloy. One such alloy was evaluated for suitability as a gold substitute in teaching the fabrication of the intracoronal cast gold restoration. The remarkable similarity of the handling characteristics of this metal to type I and type II casting gold alloys is discussed.

Costs and Cost Analysis↗
PubMed1977

A unified method for the determination of gold in biological fluids by flameless atomic absorption spectroscopy.

A new simple non-flame method of assaying serum, urine, and synovial fluid for gold by atomic absorption spectrometry (AAS) is presented. Variable absorption not due to gold is avoided by wet ashing and extraction of gold into methylisobutyl ketone. The amount of gold is determined directly in the organic phase by AAS. A linear relation between standard concentrations for serum, urine, and synovial fluid and absorption meter read-out values is obtained over the ranges 0 to 800 microgram gold/dl in serum and 0 to 80 microgram gold/dl in urine and synovial fluid. The estimated calibration curves for gold in serum, urine, and synovial fluid are found to be identical. The elimination of interferences, the high sensitivity (0.01 ppm), and the simplicity make this method superior to any other AAS methods and excellently applicable for routine determinations of gold concentrations in patients on chrysotherapy, and for research in that field as well.

Gold↗
PubMed1984

HLA antigens and toxicity to gold and penicillamine in rheumatoid arthritis.

One hundred sixty-eight patients with rheumatoid arthritis treated with chloroquine (n = 87), gold salts (n = 133) and/or penicillamine (n = 77) were investigated for possible associations between HLA antigens and toxic reactions. Patients with 2 or more side effects to gold and/or penicillamine had a significantly increased frequency of antigens HLA-B8 and DR3 compared to patients with one or without adverse reactions. Proteinuria to gold or penicillamine was significantly associated with HLA-B8 (relative risk [RR] 4.2) and DR3 (RR 14.0) whereas nonnephrologic side effects to gold or penicillamine were associated with B7 and DR2 (RR 3.5 and 2.8). Patients with skin reactions to gold had a significantly greater frequency of HLA-B7. We found no correlation between chloroquine side effects and any HLA antigen. The results suggest a genetic predisposition to toxic reactions to gold or penicillamine based on an immunologic dysregulation.

Adult↗
PubMed1981

[Ultrastructural and microanalytic study of gold depots in the synovial membrane of man and animals during treatment with sodium aurothiopropanol sulfonate].

In inflammatory rheumatism treated by gold therapy synoviocytes A are stuffed with gold salt deposits leading to a therapeutic thesaurismosis. These deposits are localized in lysosomes, then called aurosomes. However they may be rarely near collagen fibers or free, particularly in ankylosing spondylitis synovitis. Their structural morphological aspect is the same in several human rheumatic diseases and in rabbit experimental arthritis whatever the gold salt used. In such deposits, microprobe analysis shows gold and sulphur. This latter is probably given by the cell. Therapeutic effect of gold salts may imply the effect of the thiol moiety and the gold metal one.

Adult↗
PubMed1981

Gold nephropathy. Ultrastructural, fluorescent, and energy-dispersive x-ray microanalysis study.

The nephrotic syndrome developed in a patient receiving therapy with gold for rheumatoid arthritis. The results of a histopathological examination of the renal biopsy specimen were unremarkable. Immunofluorescent studies showed deposits of immunoglobulins and C3 in a granular pattern in the glomerular basement membranes. Ultrastructurally, the discrete osmiophilic immune complexes were epimembranous. By x-ray microanalysis, gold that was complexed with sulfur was present in proximal tubular cytoplasmic vacuoles and nuclei. Gold and sulfur could not be demonstrated in glomerular epimembranous deposits. The results of these studies suggest that immune complex deposition does not involve gold and sulfur acting as haptens. Gold-salt therapy may result in damage to proximal tubules that leak renal tubular antigens, which in turn complex with autoantibody and produce an autoimmune membranous nephropathy. The evidence for this mechanism is not convincing. Although the data indicate an immune-complex cause for gold-salt nephropathy, the incident antigen (or antigens) and mechanism of action remain unidentified.

Adult↗
PubMedDate not supplied

A comparison of the molecular pharmacology of gold and platinum complexes.

Auranofin and cisplatinum have antiarthritic, and antineoplastic activities respectively. Because of the chemical and biological similarities of the two compounds and the extensive studies on molecular pharmacology of cisplatinum, the information about the molecular and pharmacologic effects of these agents is presented and compared. Gold and platinum complexes both can exist in several oxidation states and form coordinate complexes of varying geometry and complexity. Gold complexes interact with bases and nucleosides but relatively little is known about their interaction with polynucleotides. Extrapolating from an understanding of the interactions of platinum complexes with polynucleotides, a number of proposals for additional research on gold complexes are presented. Substantially more information is available concerning the interactions of gold complexes and various proteins. The effects of gold complexes on intracellular macromolecules and their synthesis are poorly understood and should be studied using systems employed to study platinum analogues. It is suggested that 2 dimensional gel electrophoresis of various cellular proteins be employed to determine to which intracellular protein gold complexes bind.

Animals↗
PubMed1981

Effects of gold salts and penicillamine on serum complement.

The effects of the gold salt sodium aurothiomalate and of d-penicillamine on complement were studied in vitro. Total haemolytic complement was inhibited by 0.05-1mM gold. The inhibitory potency of gold was inversely correlated to the concentration of complement in the system, but was not diminished by albumin or decomplemented serum protein in concentrations approaching those circulating in blood. Penicillamine which itself slightly inhibited complement, prevented or reversed the action of gold. Conversion of C1s to C1esterase was not inhibited. Gold inhibited the action of C1esterase on component C4, but not the action on small-molecular synthetic ester substrates. Only very high gold concentrations (375-560 microM) inhibited the conversion of C3 to C3b. No inhibition of the alternative pathway was detected.

Complement C1s↗
PubMed1981

[Pulmonary side effects of gold treatment].

On the basis of more than 35 cases from literature a survey of clinical and paraclinical findings, diagnostic criteria, differential diagnosis, therapy and prognosis of the pulmonary reaction evoked by gold is given. The first symptoms mostly appear within the initial phase of the treatment, after several weeks to months. Unexpectedly increasing dyspnoea, weakness, cough and feeling of sickness in patients who are treated with gold salts are warning signals which refer to the possibility of a lung injury by gold. The differential-diagnostic demarcation from rheumatoid lung, a rare extraarticular manifestation of the rheumatoid arthritis, may render difficulties. The latter, however, usually refers to a slower progressing, is not or only incompletely able to involution and scarcely reacts to cortisonoids. The gold-conditioned pulmonary changes in most cases completely involve after a well-timed finish of the treatment with the gold-preparation. Cortisonoids are given for the acceleration of the remission. The prognosis is in general good. However, it depends on the fact, how long the gold treatment is still continued after the appearance of the pulmonary side-effect.

Adolescent↗
PubMed1995

Poly-L-lysine-gold complexes used at different pH are probes for differential detection of glycosaminoglycans and phosphoproteins in the predentine and dentine of rat incisor.

At neutral pH, poly-L-lysine-gold complexes labelled the predentine extensively, whereas in dentine the number of gold complexes was reduced by half. Hyaluronidase pretreatment of the section at pH 6.8, prior to labelling, suppressed most of the staining in predentine and did not affect dentine. In contrast, alkaline phosphatase pretreatment at pH 9 enhanced the gold complex labelling in predentine and removed most of the labelling in dentine. This proves that at pH 7.2, the polyanions which are stained include a heterogeneous population of glycosaminoglycans, located in predentine, and phosphoproteins, visualized in dentine. At acidic pH levels (2.9 and 1.1), the number of scored gold complexes decreased, but the ratio between predentine and dentine labelling remained constant. Hyaluronidase pretreatment removed or firmly reduced the gold complex labelling both in predentine and dentine, whereas alkaline phosphatase pretreatment of the sections at pH 9 prior to labelling did not induce any change. This argues in favour of an increased specificity of polylysine-gold complex staining for glycosaminoglycans, stained at low pH in both predentine and dentine. Differential staining of glycosaminoglycans and phosphoproteins according to the pH provides a useful tool for studying the role played respectively by the two matrix components in dentine mineralization.

Animals↗
PubMed1995

Gold, electron microscopy, and cancer therapy.

Radioactive gold has properties suitable for radiotherapy and can provide lethal irradiation to cells. If the gold is conjugated to a targeting molecule, such as an antibody, it may be possible to specifically deliver the dose to tumor cells. Various gold particles are possible candidates and include gold colloids with adsorption of antibodies or gold clusters with covalent attachment. Different sizes of gold particles are available and some may be preferred for certain situations. Problems with intravenous injection and in vivo delivery are numerous, and a more tractable application is the direct instillation into the urinary bladder of radiogold immunoconjugates to treat superficial bladder carcinoma. Preliminary studies indicate the feasibility of this approach.

Animals↗
PubMed1996

Sonochemical formation of gold particles in aqueous solution.

Gold(III) ions in aqueous solutions of NaAuCl4 were reduced to form gold particles by ultrasonic irradiation. The rate of formation of gold particles was accelerated in the presence of certain organic additives such as surfactants, water-soluble polymers and aliphatic alcohols and ketones. The rates of formation of gold particles from 1 mM Au(III) ions in pure water were 3 microM min-1 under argon atmosphere and approximately zero under air, and in solutions containing additive the rates were 9-133 microM min-1 under argon and 8-40 microM min-1 under air. Surfactants stabilized the particles as colloidal state for more than several months. The rates of formation of both hydrogen atoms and hydroxyl radicals were estimated to be equal to 25 microM min-1 in the sonolysis of pure water under argon. Three reaction pathways leading to the reduction of metal ions were proposed: (1) reduction by hydrogen atoms; (2) reduction by reducing radicals formed via reactions of hydroxyl radicals or hydrogen atoms with the additives; (3) reduction by radicals formed from thermal reaction of the additives at the interfacial region between cavitation bubbles and bulk solution and/or in the cavities. The order of the contribution of these three pathways to the reduction of gold ions was (3) > (2) > (1) in most cases. The number averages of the size of gold particles formed in surfactant solutions under argon atmosphere were about 10 nm with a fairly narrow size distribution.

Argon↗
PubMed1996

A comparison of two systems for bonding type II gold alloy to dentine: an in vitro study.

This in vitro investigation compares the shear bond strength of two systems that can be used to bond gold alloys to dentine. In the first group, sandblasted gold alloy surfaces were tin-plated and bonded to dentine using C&B-Metabond, an adhesive resin cement. In the second group sandblasted gold alloy surfaces were silicoated (Kulzer) and bonded to dentine using Denthesive II, Adhesive Bond II and Twinlook cement. Forty eight hours after bonding the bonds were stressed to failure in the sheer mode in an Instron testing machine. All data were statistically analysed (Student-t-test). The results in MPa were: Tin-plated gold to dentine 18.23; silicoated gold to dentine: 10.35. C&B-Metabond demonstrated a statistically significantly higher bond strength (p < 0.01). It can be concluded that tin-plating in conjunction with C&B-Metabond produces a stronger bond than silicoating in conjunction with Denthesive II and Twinlook cement when used to bond gold alloys to dentine.

Dental Bonding↗
PubMed1957

Electron microscopy of HeLa cells after the ingestion of colloidal gold.

Tissue cultures of HeLa cells were grown in media containing colloidal gold, and after various intervals, the cells were fixed, embedded, and sectioned for electron microscopy. Uncoated grids with small holes were used in many of the experiments. Intracellular particles of gold were identified in areas surrounded by single membranes, in moderately dense granules, in globoid bodies, and in the cytoplasmic matrix. Gold particles were not found in typical mitochondria, Golgi complex, ergastoplasm (granular forms of endoplasmic reticulum), or nuclei. The phenomenon of pinocytosis was considered to be the most likely means by which the gold particles were ingested, and the locations of gold particles appeared to have significance concerning theories that membranous organelles of the cytoplasm may be derived from the cell membrane.

Animals↗
PubMed1982

Gold induced enterocolitis: case report and a review of the literature.

The use of gold therapy in rheumatoid arthritis is not without risk. Although the better known side effects are bone marrow suppression and renal involvement, gold induced enterocolitis has been described. This paper reports a 59-year-old female recently treated with gold therapy for rheumatoid arthritis who developed bloody diarrhoea, toxic dilatation and perforation of her colon. The absence of features of inflammatory bowel disease or infection indicates gold as a possible causative agent. Pathogenesis, therapy and a review of the literature of gold induced enterocolitis are described.

Adult↗
PubMed1987

Inhibition of human endothelial cell proliferation by gold compounds.

Neovascularization has a role in the propagation of rheumatoid synovitis because the spread of mononuclear cell infiltration and the growth of pannus are dependent on the growth of new blood vessels. Growth of such vessels requires local endothelial cell (EC) proliferation. Inhibition of synovial EC proliferation, therefore, would have the potential to diminish rheumatoid inflammation. We have, therefore, studied the effects of gold sodium thiomalate (GST), auranofin, and gold chloride on the proliferation of human umbilical vein EC. GST suppressed both basal and EC growth factor-induced tritiated thymidine incorporation into EC in a dose-dependent fashion. Inhibition was observed with concentrations as low as 1 microgram/ml GST, 5 micrograms/ml gold chloride, and 0.1 microgram/ml auranofin, levels attainable in blood and synovium of patients. These results suggest that gold compounds have an antiangiogenic effect. The low concentrations inhibiting EC proliferation suggest that gold compounds may suppress rheumatoid synovitis by reducing the number of small blood vessels available for mononuclear cell infiltration and synovial tissue proliferation.

Arthritis, Rheumatoid↗
PubMed2000

Injectable gold for rheumatoid arthritis.

OBJECTIVES: To estimate the short-term benefit and risk of side-effects of injectable gold for rheumatoid arthritis. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Group trials register, and Medline, up to July 1997, using the search strategy developed by the Cochrane Collaboration (Dickersin 1994). The search was complemented with bibliography searching of the reference list of the trials retrieved from the electronic search. Key experts in the area were contacted for further published and unpublished articles. SELECTION CRITERIA: Randomized clinical trials (RCT) comparing injectable gold against placebo in patients with rheumatoid arthritis were included. DATA COLLECTION AND ANALYSIS: Methodological quality of the RCTs was asessed by two reviewers (MS, BS) (kappa=1.0). Rheumatoid arthritis outcome measures were extracted by two reviewers from the publications for the 6 month endpoint. Sufficient data was obtained to conduct a pooled analysis of the number of swollen joints, physician global assessment, patient global assessment and erythrocyte sedimentation rate (ESR). Results were analyzed as standardized weighted mean differences for swollen joints and global assessments and weighted mean differences for ESR. Toxicity was evaluated with pooled odds ratios for withdrawals. Heterogeneity was estimated using a chi-square test. Fixed effects models were used throughout. MAIN RESULTS: Four trials and 415 patients were included. A statistically significant benefit was observed for injectable gold when compared to placebo. The standardized weighted difference (effect size) between gold and placebo for the number of swollen joints was -0.5, translating into a percentage change of 30% in favour of gold adjusted for placebo. Statistically significant differences were also observed for ESR and patient and physician assessments. Twenty two percent of the treated patients withdrew from toxicity compared to 4% of controls (OR=3.9 - 95%Cl: 2.1 - 7.2). REVIEWER'S CONCLUSIONS: Although its use can be limited by the incidence of serious toxicity, injectable gold has an important clinically and statistically significant benefit in the short term treatment of patients with rheumatoid arthritis.

Antirheumatic Agents↗
PubMed1993

Fine-needle aspiration biopsies of metastatic neuroendocrine tumors in liver: use of transmission electron microscopy and protein A gold technique in diagnosis.

Five fine-needle aspiration biopsies of liver were studied to evaluate the use of electron microscopy and protein A gold technique in the diagnosis of metastatic neuroendocrine tumors. All five cases had cytologic features suggestive of neuroendocrine tumors and neurosecretory granules on ultrastructural examination. The aspirates were stained by the immunoperoxidase technique and the postembedding protein A gold technique using the antibody to chromogranin A. Three cases were positive for chromogranin A by both immunoperoxidase and protein A gold techniques. Two cases were positive by protein A gold technique and negative by immunoperoxidase technique. Confirmation of neurosecretory granules by immunochemistry is ideal, since ultrastructurally they can be mimicked by other electron-dense inclusions. Advantage of the protein A gold technique is the use of the same material for both ultrastructural evaluation and the protein A gold technique.

Adult↗
PubMed1999

Novel Method for Preparation of a Nanosized Gold Catalyst Supported on TiO2.

A TiO2 surface was readily modified with nanosized gold particles prepared by the thermal relaxation technique. Adsorption of the gold particles was very rapid, and the adsorbed gold particles distributed independently. By the two-step calcination of the modified TiO2, the nanosized gold particles were immobilized on the TiO2 surface without size growth or coagulation. The supported gold particles showed low-temperature catalytic activity on CO oxidation. The preprepared nanosized gold particles interacted with TiO2. Copyright 1999 Academic Press.

Journal Article↗