SEARCH · Search PubMed

Results for “GOLD”

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.

SourceResearch connectionFrom yearThrough year

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

At least 919 records · Page 51Linked to original sources

PubMedDate not supplied

Receptor binding and internalization of a unique biologically active angiotensin II-colloidal gold conjugate: morphological analysis of angiotensin II processing in isolated vascular strips.

It is well recognized that following binding of ligand, many receptors undergo a process of agonist-induced receptor-mediated endocytosis (RME) or internalization. We recently characterized the intracellular pathway and kinetics of angiotensin II (AII)-RME in cultured explant-derived rat aortic vascular smooth muscle cells (VSMCs). To definitively study vascular internalization of AII, however, it is critical to examine AII binding and uptake in intact, differentiated VSM. For the present study, we used a unique, biologically active AII-colloidal gold conjugate to qualitatively examine, by transmission electron microscopy, the ultrastructural details of AII binding and internalization in intact VSM. Strips of isolated, cleaned, and denuded rat aortic smooth muscle were incubated with AII-gold probe for 2 h at 4 degrees C to allow binding of the complex without simultaneous internalization. After rinsing to remove unbound AII-gold, the strips were incubated at 37 degrees C (5-90 min) to initiate internalization. These studies show that AII initially binds over the entire surface of medial VSMCs. Following binding, the AII is internalized via small receptosomes which likely represent clathrin-coated vesicles. By 20 min after internalization, gold particles are evident within large lysosome-like vesicles deep within the VSM. There was no evidence of association of gold particles with the Golgi network at any of the time periods examined. Gold particles were occasionally observed in perinuclear regions after 90 min at 37 degrees C, although this did not appear to represent a typical pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗

PubMed1980

Pneumonitis caused by gold salt therapy: evidence for the role of cell-mediated immunity in its pathogenesis.

Gold salt-related pneumonitis is now an established clinical entity, but the mechanism for the induction of the pulmonary disease is not known. In 2 patients with this disorder, we observed elaboration of the lymphokines, migration inhibition factor (MIF) and macrophage chemotactic factor (MCF), by peripheral blood lymphocytes after incubation with gold salt. Incorporation of [3H]thymidine was not seen with several different dosages of gold salt. Control lymphocytes from normal subjects, from patients with rheumatoid arthritis but not receiving gold salt, and from patients with rheumatoid arthritis receiving gold salt but without hypersensitivity manifestations, were all unresponsive to the drug. These results suggested that the pneumonitis associated with chrysotherapy is also associated with a specific cellular immune response to the drug. Further, they point to the necessity of evaluating multiple parameters of cellular immunity, because in these patients there was a dissociation between blast transformation and mediator production. In addition, they underscored the need for further observations of cellular responsiveness in patients receiving gold salt therapy with and without overt pulmonary disease.

Female↗

PubMed2005

A renewable electrochemical magnetic immunosensor based on gold nanoparticle labels.

A particle-based renewable electrochemical magnetic immunosensor was developed by using magnetic beads and gold nanoparticle labels. Anti-IgG antibody-modified magnetic beads were attached to a renewable carbon paste transducer surface by magnet that was fixed inside the sensor. Gold nanoparticle labels were capsulated to the surface of magnetic beads by sandwich immunoassay. Highly sensitive electrochemical stripping analysis offers a simple and fast method to quantify the capatured gold nanoparticle tracers and avoid the use of an enzyme label and substrate. The stripping signal of gold nanoparticles is related to the concentration of target IgG in the sample solution. A transmission electron microscopy image shows that the gold nanoparticles were successfully capsulated to the surface of magnetic beads through sandwich immunoreaction events. The parameters of immunoassay, including the loading of magnetic beads, the amount of gold nanoparticle conjugate, and the immunoreaction time, were optimized. The detection limit of 0.02 microg ml(-1) of IgG was obtained under optimum experimental conditions. Such particle-based electrochemical magnetic immunosensors could be readily used for simultaneous parallel detection of multiple proteins by using multiple inorganic metal nanoparticle tracers and are expected to open new opportunities for disease diagnostics and biosecurity.

Biosensing Techniques↗

PubMed1978

Coloidal gold, ferritin and peroxidase as markers for electron microscopic double labeling lectin techniques.

Three markers, colloidal gold, ferritin and peroxidase, were checked for usefulness in double labeling of lectin-binding sites. The amount of various lectins for the stabilization of good sols of a different particle size was evaluated. Several lectin-gold complexes were prepared for electron microscopic labeling purposes, and the optimal amount of various lectins needed for stabilization of gold solutions of a different particle size was determined. The following combinations were investigated for their usefulness in labeling two different lectin-binding sites: lectin-gold and lectin-gold (different particle size), lectin-gold and lectin-ferritin, as well as lectin-ferritin and lectin-peroxidase. Of these combinations the latter did not give satisfactory results for double labeling. In all single and double labeling techniques with the above mentioned markers the quantitative evaluation of the number of lectin-binding sites is not feasible, but these techniques will be of considerable value for the investigation of the dynamics of different lectin-binding sites on the cell surface.

Cell Line↗

PubMed1984

Immunolabeling of adenohypophysial cells with protein A-colloidal gold--antibody complex for electron microscopy: use of the freeze-substitution technique in tissue preparation.

The value of the freeze-substitution (FS) method for preparing tissues for electron microscopic immunohistochemistry was studied by comparing anterior pituitary cells prepared by this method and by a conventional method. Ultrathin sections of tissues embedded in Epon were subjected to immunostaining. The antigens adrenocorticotropin (ACTH) and prolactin (PRL) in a single ultrathin section were demonstrated by a simple double-labeling technique using a protein A-colloidal gold-antibody (pAG-Ab) complex. The preservation of cellular ultrastructure was superior in preparations obtained by FS. Gold-labeling was seen over secretory granules, and in ACTH cells also over the cytoplasmic matrix. The labeling was more intense in preparations obtained by FS, judging from the numbers of gold particles. In the double-labeling procedure, in which the pA-small colloidal gold-anti-PRL complex and pA-large colloidal gold-anti-ACTH complex were applied sequentially to sections, no cross-labeling with small and large gold particles was observed. It is concluded that if the antisera are sufficiently specific, the use of FS and the pAG-Ab complex is very effective in peptide immunohistochemistry. However, in the double-labeling procedure it is essential that the Fc-binding sites of pAG are saturated by the use of excess amounts of antibodies.

Animals↗

PubMed1984

Unlabeled antibody methods in electron microscopy: a comparison of single and multistep procedures using colloidal gold.

A comparative study of five unlabeled antibody methods was conducted on the electron microscopic level using bridging techniques and colloidal gold. The study was based on the principles of the single-step colloidal gold (GLAD) method (Larsson L: Nature 282:743, 1979) and the multistep single- and double-bridge techniques used in postembedding immunoperoxidase procedures (PAP) (Sternberger LA: Immunocytochemistry, 2nd ed. Wiley, New York, 1979). Using medullary thyroid carcinoma and the same lot of primary antiserum (goat anti-calcitonin) for each procedure, it was shown that adequate localization of calcitonin with the single-step GLAD method was attainable only at dilutions of 1:100 or lower. The single-bridge technique using goat anti-calcitonin, sheep anti-goat immunoglobulin (Ig)G, and goat anti-calcitonin and antigen-coated gold, respectively, worked well at dilutions of up to 1:5000 but not at dilutions of 1:10,000, while single- and double-bridging techniques utilizing goat anti-calcitonin, sheep (Sh) anti-goat IgG, and sheep anti-goat IgG-coated gold produced good localization at a 1:10,000 dilution of primary antiserum. A two-step method using goat anti-calcitonin and sheep anti-goat IgG-coated gold, respectively, appeared to be the most sensitive technique, with adequate antigen localization occurring at a dilution of 1:25,000. While in our hands the two-step method appeared superior in sensitivity to the single-bridge IgG-coated gold technique, each method has its own advantages depending on the individual needs of the researcher.

Animals↗

PubMed1988

High-resolution cytochemistry of neuraminic and hexuronic acid-containing macromolecules applying the enzyme-gold approach.

We localized acidic glycoconjugates at the ultrastructural level by applying the enzyme-gold approach. Neuraminidase and hyaluronidase were adsorbed to colloidal gold particles and applied to tissue sections under optimal conditions for their enzymatic activity. Neuraminidase-gold labeling was distributed over the Golgi apparatus and associated secretory granules in exocrine pancreatic cells and duodenal goblet cells. Mitochondria were labeled over inner membranes. Labeling was also found over the dispersed chromatin in the nucleus. Plasma membranes, particularly the apical side, were labeled by gold particles. On the other hand, incubation of tissue sections with the hyaluronidase-gold complex resulted in intense labeling of the rER membranes, the plasma membrane, and the dense chromatin in the nucleus. Labeling was also found over the Golgi apparatus and associated secretory granules, but only in duodenal goblet cells. Specificity of the results was confirmed by various control experiments performed, indicating that the enzyme-gold technique is useful for detecting linked-sugar residues on tissue thin sections. Labelings found over intra- and extracellular compartments in the present work are discussed in light of previous biochemical indications as well as of other histochemical detections of these glycoconjugates.

Animals↗

PubMed1992

Silver enhancement of gold antibody probes in pre-embedding electron microscopic immunocytochemistry.

In pre-embedding EM immunocytochemistry with gold probes, the gold must be small enough to penetrate through cell membranes treated with mild detergents. Antibodies labeled with small gold probes (1-1.4 nm) are too small to be resolved in thin sections but can be seen if they are silver-enhanced after the gold has bound to the antigens in the cells. We investigated several aspects of gum arabic-silver lactate-hydroquinone enhancement solution (Danscher solution) by examining gold-conjugated antibodies embedded in agar, sectioned on a vibrotome, and enhanced with different solutions. The rate of silver enhancement was optimized in 50% gum arabic and 200 mM HEPES buffer, pH 5.8. We also examined chemicals used as developers and found that N-propyl gallate (NPG) gave a more uniform development than the routinely used hydroquinone (HQ). The diameter of the silver-enhanced particles after incubation in osmium tetratoxide (OSO4) decreased somewhat with longer incubation time and higher percentages, but the density (number per unit area) of silver-enhanced particles was little changed. The loss of silver-enhanced particle diameter was reduced by lowering the concentration of OSO4 to 0.1%. Comparison of commercial small gold probes showed that NPG enhancement of Nanogold gave more uniform particle size and a better correlation between enhancement time and particle density. When this procedure was applied to cell cultures with monoclonal antibodies, the silver-enhanced particles were similar to those in the agar sections. When free-floating tissue sections were used, longer silver enhancement times were needed to obtain similarly sized particles. This new NPG-silver-enhancement procedure offers a reliable and easy method to localize proteins in cultured cells and tissue sections by pre-embedding electron microscopic immunocytochemistry.

Animals↗

PubMed1992

A novel methodology for double protein A-gold immunolabeling utilizing the monovalent fragment of protein A.

A method for sequential protein A-gold immunolabeling is described whereby the binding of second gold probe to the first antibody-protein A-gold complex is reduced to acceptably minimal levels. Immunolabeling of thin sections of embedded pituitary tissue was used as a model system. After an initial immunolabeling for prolactin, sections were incubated in normal serum (rabbit) followed by a monovalent fragment of protein A. These latter two incubations reduced artifactual second gold probe label over prolactin-labeled secretory granules to minimal levels (much less than 1 particle per granule) when sections were subsequently immunolabeled with normal serum. The combination of normal serum and protein A fragment incubations saturates IgG and protein A binding sites on the first antibody-gold probe complex. The latter is thereafter unable to bind further IgG (and thus gold probe) because of the monovalent nature of the protein A fragment. It is suggested that this methodology may be extended to multiple immunolabeling procedures for electron microscopy. In addition, when used before single labeling this method may be an effective way to minimize nonspecific IgG binding in cases where the tissue or antibody under study may be a problem.

Animals↗

PubMed1993

Diamine oxidase-gold labels histamine in human mast-cell granules: a new enzyme-affinity ultrastructural method.

We developed a post-embedding ultrastructural enzyme affinity-gold technique to label histamine. Diamine oxidase (DAO)-gold complex was prepared and tested for specificity with routinely processed, Epon-embedded, histamine-rich human mast-cell granules and histamine-agar test blocks, both of which were labeled. Specificity controls included removal of staining by DAO digestion of Epon sections containing mast cells or by filtering DAO-gold over histamine-agarose beads, and a wide variety of controls (for these specificity controls) that did not abrogate mast-cell granule or histamine-agar block labeling with DAO-gold. Internal negative controls in each sample included the failure of DAO-gold to stain Type II alveolar pneumocyte lamellar bodies or altered, swollen mast-cell granules from which histamine has been released. The new post-embedding enzyme affinity-gold technique is effective in optimally prepared ultrastructural samples that allow clear identification of key ultrastructural morphology.

Amine Oxidase (Copper-Containing)↗

PubMed1997

Nuclear translocation of gold labeled-testosterone-bovine serum albumin conjugate through the nuclear double membranes in rat spermatids.

We have demonstrated that testosterone-bovine serum albumin conjugate labeled with 2-nm colloidal gold (testosterone-BSA-gold) injected into the vascular system of rat becomes visible as silver deposits on the sections of tissues embedded in epoxy resin after silver enhancement and enters the androgen-target cell nuclei, e.g. round spermatids, but not the non-target cell nuclei. The diameter of the silver deposits depends on the duration of silver enhancement. In this study, to make clear the transfer route of testosterone-BSA-gold into the round spermatid nucleus, the testis of rat injected testosterone-BSA-gold was observed under electron microscope after silver enhancement for short periods of time. The small silver deposits were present on the cell membrane, vesicles, Golgi region, acrosome, subacrosomal space, both the post-acrosomal and the subacrosomal nuclear envelope, and the nucleoplasm in the cap-phase spermatids. The silver deposits were also found in the perinuclear cisterna of post-acrosomal nuclear envelope, but not in the nuclear pore. When the spermatids were observed at high-power magnification without the silver enhancement, the outer nuclear membrane showed many irregular invaginations toward the inner nuclear membrane in the post-acrosomal nuclear envelope. Furthermore, a double-membrane-like vesicle seemed to be present in the nuclear envelope. In the vesicle, the gold particles were present along the inner membrane. These results suggest that testosterone-BSA-gold can enter the nucleoplasm through some route provided by the nuclear double membranes in both the post-acrosomal and the subacrosomal nuclear envelope.

Acrosome↗

PubMed1998

The influence of silicosis on deteriorating lung function in gold miners.

STUDY OBJECTIVE: To reexamine the symptoms, lung function, and chest radiographs of older gold miners who continued to work in or around gold mines 5 years after their enrollment in the cohort. DESIGN: A follow-up study of a stratified sample of a cohort of gold miners. SETTING: A health-care center for 24 gold mines in Welkom, South Africa. POPULATION: A stratified, random sample of 242 miners who were part of a cohort of 1,197 gold miners who had been employed underground in gold mines for a mean period of 29 years. No silicosis was apparent on entry in 59 men, 78 had silicosis with category 1 nodule profusion, 73 had category 2, and 32 had category 3. MEASUREMENTS: The men were assessed with questionnaires, lung function tests, and chest radiographs approximately 4.5 years after their initial assessment. RESULTS: Radiologic features of silicosis had progressed an average of one subcategory (eg, 2/1 to 2/2) in the follow-up period. Lung function deteriorated more rapidly in the men with silicosis and the deterioration increased in proportion to the degree of silicosis at the start of the study. Thus, the annual loss of FEV1 was 37 mL in those without silicosis, 57 mL in those with category 1, 100 mL with category 2, and 128 mL in the men with category 3 nodule profusion (p=0.000001). A similar pattern of loss was noted for the FVC (p=0.00003) and the single-breath lung diffusion (p=0.004). These changes remained significant after controlling for age, original lung function, and for smoking. CONCLUSIONS: The men with silicosis suffered a substantial loss of lung function during the period of follow-up that was directly in proportion with the nodule profusion on their initial chest radiographs.

Age Factors↗

PubMed1995

Improved gold chloride procedure for nerve staining in whole mounts of rat corneas.

The purpose of this study was to modify the gold chloride procedure for studies of total innervation in corneal whole mounts to provide a decrease in nonspecific background staining and to eliminate the progressively deteriorating stain quality of standard gold chloride techniques. Modifications included use of cryoprotective agents, mechanical removal of Descemet's membrane-endothelium complex prior to fixation, treatment with alpha amylase, and halting the reduction of gold chloride to metallic gold using Kodak rapid fixer with hardener. Rat corneas were stored at -70 C in O.C.T. compound. The Descemet's membrane-endothelium complex was removed after thawing, and corneas were fixed in 4% NaPO4-buffered paraformaldehyde with 8% sucrose. Fixed corneas were incubated in NaPO4-buffered saline containing alpha amylase, placed in 100% lemon juice, then in 1% gold chloride solution, transferred to glacial acidic acid, placed in rapid fixer, rinsed in NaPO4-buffered saline, and dehydrated in graded alcohols. Flat mounts of whole corneas were examined using contralateral corneas as controls. Freezing corneas in O.C.T. compound, removal of the Descemet's membrane-endothelium complex, and treatment with alpha amylase reduced non-specific background staining compared to controls. Treatment with Kodak rapid fixer prevented the deterioration of staining quality for at least 8 months. These improvements allow the gold chloride technique to be used with immunohistochemical procedures where the reaction products would be obscured by background staining.

Animals↗

PubMed1999

Goldschlager allergy in a gold allergic patient.

We describe the case of gold allergy after ingestion of GOLDSCHLAGER, a gold-containing liquor, in a patient with a previous allergy to gold jewelry. The patient was not aware that genuine gold particles were contained in the schnapps liquor and that ingestion could result in a reaction similar to that experienced by individuals sensitive to gold jewelry. Clinicians should be familiar with the presence of gold particles in GOLDSCHLAGER liquor and the potential for allergic reactions to occur in those so predisposed.

Adult↗

PubMed2001

Long term results of radioactive gold grain implantation for the treatment of persistent and recurrent nasopharyngeal carcinoma.

BACKGROUND: Brachytherapy is useful for the reirradiation of nasopharyngeal carcinoma. In the current study, the long term treatment results of permanent radioactive gold(198) grain interstitial implantation in patients with persistent and recurrent nasopharyngeal carcinoma were reviewed. METHODS: Gold grain implantation was performed under direct vision with a split palate approach to provide 60 grays (Gy) 0.5 cm away from the plane of implantation. Between August 1986 and May 1999, 106 patients were treated with gold grain implantation (45 patients for persistent disease, 53 patients for first recurrence, and 8 patients for second recurrence in the nasopharynx). All patients had histologically proven disease by biopsy before undergoing implantation. RESULTS: Patients with persistent disease and those with first recurrence did well with the gold grain implantation. The 5-year local control rates for patients with persistent disease, first recurrence, and second recurrence in the nasopharynx were 87.2%, 62.7%, and 23.4%, respectively (P = 0.0004). The 5-year metastasis free survival rates were 68.1%, 60.3%, and 40%, respectively, for the 3 groups (P = 0.048). The overall survival rates at 5 years for the 3 groups were 79.1%, 53.6%, and 42.9%, respectively (P = 0.0047). Patients with computed tomography evidence of disease extension outside the nasopharynx had a lower local control rate compared with patients whose disease was confined to the nasopharynx (5-year local control rate of 52% vs. 72.3%; P = 0.031). The size of the lesion was not found to be an independent prognostic factor for local control after implantation. Multivariate analysis showed only an indication for implantation (persistent disease, first recurrence, and second recurrence) to be a significant prognostic factor for local control. Complications attributed to gold grain implantation included headache, palatal fistula, and mucosal radiation necrosis at the site of implantation, and were reported to occur in 28.3%, 18.9%, and 16%, respectively, of patients. CONCLUSIONS: For selected patients with disease confined to the nasopharynx, gold grain implantation is an effective salvage treatment for persistent and recurrent nasopharyngeal carcinoma.

Adult↗

PubMed2001

Polyvinyl alcohol as an immobilization matrix--a case of gold biosorption.

The use of polyvinyl alcohol (PVA) as a matrix for cell immobilization has been extensively studied in various biological systems. However, its suitability has not been reported in biosorption studies where inactivated cells are used as biosorbents. In this work, PVA and alginate as immobilization matrices (for the biosorption of gold by a fungal biomass) were investigated by examining their physical and chemical properties. Compared to alginate gels, PVA gels were shown to be more resistant to mechanical abrasion, and more stable over a wide pH range. Although the PVA matrix did not affect the equilibrium uptake in gold biosorption studies, the time required to attain a removal of 80% of the initial metal concentration was 1.7 times that of the freely suspended biosorbent. This contrasts with the alginate immobilized biosorbent which required an increase of well over ten times the duration to attain the same removal efficiency. Results indicated that PVA gels conferred a lower mass transfer resistance than alginate gels. Gold biosorption by the PVA-immobilized fungi followed the commonly used Langmuir and Freundlich adsorption isotherm models although the former gave a better fit. The uptake of gold was dependent on the initial gold concentration and the biomass loading. Using a fungal biosorbent and gold ions as the model system, the results demonstrate the potential in the use of the PVA as a cell immobilisation matrix for biosorption studies.

Absorption↗

PubMedDate not supplied

Selective recovery of gold from secondary sources by Dowex-50-X8 sorbed Rhodamine-B resin.

Gold recovery from spent materials has been performed on modified cation-exchange resin. The modified resin was prepared by sorption of Rhodamine-B on Dowex-50-X8 (Na+) resin at pH 2.0. Distribution coefficients of gold ion have been determined with 15% (w/v) potassium chloride in different concentrations of hydrochloric acid. On the basis of Kd values quantitative separation of gold from secondary sources has been achieved. Gold(III) has been selectively separated from gold containing spent materials by column chromatography using modified ionexchange resin and the recovery was more than 92% compared to conventional cyanidation process. The results of the proposed method are suggestive of its applicability to other gold containing secondary sources.

Anion Exchange Resins↗

PubMed2004

Why not gold? Contemporary esthetics and restorative practice.

In today's dental world, there are many more options of materials and equipment than there was years ago. It can be very confusing for anyone to sift through the marketing and lectures and determine which of the new materials are best suited for our patients. Classic gold techniques have been around for over 100 years and have an obvious track record. Leinfelder (7) has stated, "Gold alloys are certainly the best materials by far in terms of maintaining a functional occlusion and longevity." Underutilized in the recent past, gold is undergoing a comeback in many areas. A major dental company recently introduced a new casting gold and recent advertisements for gold-related products have reappeared in dental magazines. It is incumbent upon the modern dental professional to be aware of all the restorative options available, learn how to perform them, and then choose the technique that will be the most appropriate for each situation. Longevity should always be a factor in the decision making process and gold is the answer in many applications.

Crowns↗