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PubMed1983

Morphological heterogeneity among Salmonella lipopolysaccharide chemotypes in silver-stained polyacrylamide gels.

The morphological heterogeneity of lipopolysaccharides (LPSs) among salmonella mutants with different LPS chemotypes was analyzed in silver-stained polyacrylamide gels. The biochemical differences in the LPS chemotypes were reflected in the unique profiles of the purified LPSs. The LPS profiles in the whole-cell lysates were also unique for each chemotype. (Whole-cell lysates were assessed by a method which preferentially silver stains LPS and by a proteinase K digest of whole-cell lysates. The silver-stained LPS profiles of proteinase K-digested lysates were similar to the homologous purified LPS and could be used to preliminarily characterize the LPS chemotype before purification.) In summary, biochemical variation in LPS composition can be detected in silver-stained polyacrylamide gels.

Electrophoresis, Polyacrylamide Gel↗
PubMed1988

Topical silver sulphadiazine--a new drug for ocular keratomycosis.

The efficacy of silver sulphadiazine in human keratomycosis has not been evaluated so far. Encouraged by the success of an earlier experimental trial, a prospective, controlled, randomised double masked clinical study was designed to evaluate the efficacy of 1% silver sulphadiazine ophthalmic ointment in 20 eyes of mycotic keratitis. Miconazole 1% was used for comparative evaluation in another 20 eyes. Silver sulphadiazine had a higher success rate (80% vs 55%) than miconazole. It had broad antifungal activity and was found to be effective in fusarium keratitis. Absence of side effects, economy, and its efficacy in deeper and extensive lesions were additional advantages. It is concluded from this study that silver sulphadiazine is a safe and effective broad spectrum antifungal agent which can be used for the treatment of human keratomycosis.

Administration, Topical↗
PubMed1993

Combined silver Perls's stain for differential staining of ringed sideroblasts and marrow iron.

During a study of nucleolar organiser regions, a modified silver stain was found to be a sensitive marker for the iron in ringed sideroblasts, more so than Perls's stain when the marrow iron stores were low. To enhance the usefulness of the silver stain, a combined silver Perls method was developed. This stains the ringed sideroblast iron black and haemosiderin blue, thus rendering the detection of ringed sideroblasts easier even when marrow iron stores are excessive. AT the same time, it allows marrow iron content to be evaluated. The silver reagent in this combined method probably shows phosphate rather than the iron present in the abnormal mitochondria in ringed sideroblasts. This facilitates the differential staining of ringed sideroblast "iron" and haemosiderin.

Bone Marrow↗
PubMed1992

Inactivation of coliphage MS-2 and poliovirus by copper, silver, and chlorine.

The efficacy of electrolytically generated copper and silver ions (400 and 40 micrograms/L, respectively) was evaluated separately and in combination with free chlorine (0.2 and 0.3 mg/L) for the inactivation of coliphage MS-2 and poliovirus type 1 in water at pH 7.3. The inactivation rate was calculated as log10 reduction/min: k = -(log10 Ct/C0)/t. The inactivation of both viruses was at least 100 times slower in water containing 400 and 40 micrograms/L copper and silver, respectively (k = 0.023 and 0.0006 for MS-2 and poliovirus, respectively), compared with water containing 0.3 mg/L free chlorine (k = 4.88 and 0.036). Significant increases in the inactivation rates of both viruses were observed in test systems containing 400 and 40 micrograms/L copper and silver, respectively, with 0.3 mg/L free chlorine when compared with the water systems containing either metals or free chlorine alone. Poliovirus was approximately 10 times more resistant to the disinfectants than coliphage MS-2. This observation suggests either a synergistic or an additive effect between the metals and chlorine for inactivation of enteric viruses. Use of copper and silver ions in water systems currently used in swimming pools and spas may provide an alternative to high levels of chlorination.

Chlorine↗
PubMed1983

Distribution of radioactive silver in the subcellular fractions of various tissues of the rat and its binding to low molecular weight proteins.

In view of the electron microscopic evidence that silver does not penetrate cellular barriers, the distribution of radioactive silver in rat blood and subcellular fractions of liver, kidneys, spleen, and forebrain was studied. It was found that 24 h after a single intraperitoneal injection high levels of radioactivity were reached which decreased at different rates in the various tissues studied. In plasma, liver, and kidneys there was an initial rapid loss of radioactivity which was followed by a slower rate of loss. In the blood, forebrain, and spleen the loss of radioactivity was linear and somewhat slower than in the other three tissues. The cytosols of the liver and kidneys contained 60% while those of the forebrain and spleen contained 30% of the total radioactivity found in the tissue homogenates. Gel filtration on Sephadex G-75 showed that all cytosols contained two peaks of radioactivity; a high molecular weight peak which eluted just after the void volume and a low molecular weight peak. The amount of radioactivity in both peaks was, however, much lower in the chromatographic peaks of the forebrain and spleen than that found in those of the liver and kidneys. Furthermore, the spleen had a comparatively very small low molecular weight radioactive peak. In vitro experiments with liver cytosol showed similar results to those found in vivo in that the high molecular weight radioactive peak could be removed by heat. It is concluded that silver does enter cells and that silver thionein exists in the cytosols of forebrain, spleen, kidney, and liver.

Animals↗
PubMedDate not supplied

Silver nitrate: antimicrobial activity related to cytotoxicity in cultured human fibroblasts.

The aims of this study were to ascertain whether silver nitrate (AgNO3) concentrations below those used in clinical practice inhibit bacterial growth, and in parallel study the cytotoxic effects on human fibroblasts. The cytoprotective effects of fetal calf serum (FCS) were also evaluated. The cytotoxic effects of eight different silver nitrate concentrations were determined by assessing mitochondrial activity of viable cells capable of cleaving tetrazolium salts. Antimicrobial activity of AgNO3, range: 7-550 x 10(-5)%, was tested against Staphylococcus aureus, Citrobacter freundii, and Pseudomonas aeruginosa. Silver nitrate concentrations exerting antimicrobial effects were: S. aureus, >70 x 10(-5)%; P. aeruginosa, >/=270 x 10(-5)%, and C. freundii, >/=550 x 10(-5)%. With 2% FCS, the lowest AgNO3 concentration studied (7 x 10(-5)%) showed cytotoxic effects (cell survival 71 +/- 19%) at only 2 h of incubation. Under these conditions AgNO3 cytotoxicity was time- and concentration-dependent in all exposure periods. Cytotoxicity was greatly enhanced causing 76% fibroblast growth inhibition at concentrations of 14 x 10(-5)% and contact time of 2 h. The AgNO3 concentration of 7 x 10(-5)% was also cytotoxic with 5% FCS in the media compared with controls, although cell survival was higher than with 2% FCS. The cytoprotective action of FCS was clearly shown at the concentration of 10% at which AgNO3 cytotoxicity of 7 x 10(-5)% to 28 x 10(-5)% was partially or completely inhibited. Our results show that AgNO3 at concentrations 100-700 times more diluted than that normally used in clinical practice retained effective inhibitory activity against some of the above-mentioned microorganisms. However, even these concentrations are cytotoxic for cultured fibroblasts. Thus, silver nitrate concentrations up to 100 times more diluted can be used, since they possess bacterial growth-inhibiting power, are less cytotoxic and therefore favour wound healing.

Anti-Infective Agents, Local↗
PubMed2003

Silver-coated textiles reduce Staphylococcus aureus colonization in patients with atopic eczema.

BACKGROUND: In atopic eczema (AE), skin colonization with Staphylococcus aureus is known to play a major triggering and possibly pathophysiological role. METHODS: In this open-labeled controlled side-to-side comparative trial, affected sites (flexures of both elbows) in 15 patients diagnosed as having generalized or localized AE were evaluated regarding S. aureus colonization and clinical severity of AE over a 2-week period. Flexures of the elbows were covered with silver-coated textiles on one arm and cotton on the other for 7 days followed by a 7-day control period. RESULTS: A highly significant decrease in S. aureus colonization could be seen on the site covered by the silver-coated textile already 2 days after initiation lasting until the end of the treatment. Seven days after cessation, S. aureus density remained significantly lower compared to baseline. In addition, significantly lower numbers of S. aureus were observed on the silver-coated textile site in comparison to cotton at the end of treatment as well as at the time point of control. Clinical improvement correlated with the reduction of S. aureus colonization. CONCLUSION: A superior improvement achieved by silver-coated compared to cotton textiles paralleled a potent anti-S.-aureus effect.

Coated Materials, Biocompatible↗
PubMed1979

Sequential silver staining and hybridization in situ on nucleolus organizing regions in human cells.

Chromosome preparations from eight individuals were first stained with silver nitrate to reveal the nucleolus organizing regions (NORs) and then hybridized in situ with ribosomal RNA. In six individuals the size of the silver-staining regions was positively correlated with the amount of label present after hybridization in situ. Thus the variation in silver-staining intensity among chromosomes was largely explained by variation in the number of rDNA gene copies per NOR. However, in two individuals this correlation was absent, suggesting that other factors can also influence the size of the silver-staining region.

Chromosome Banding↗
PubMed1991

The immunogold-silver staining procedure in the study of freshly suspended Langerhans cells at the transmission electron microscopic level.

The potential of an immunogold-silver staining for the study of human suspended Langerhans cells at the transmission electron microscopic level was evaluated. Cells were labeled, by using a preembedding technique, with 5-nm colloidal gold particles followed by silver enhancement. The use of small colloidal gold particles permits a detection of small quantities of antigen; the metallic silver deposition around gold granules gives rise to a large electron-dense marker which can be easily detected even at low magnification. Ultrastructural details were well preserved, and the background was not significant. The major advantage of the present immunogold-silver staining is that it enables to detect labeled cells easily, even when limited amounts of antigenic moieties are present on a low percentage of cells. Therefore, a rapid and simultaneous evaluation of both immunophenotype and ultrastructural details of investigated cells is allowed.

Antigens, CD↗
PubMed1990

Detection of antibodies to the human immunodeficiency virus by a silver-enhanced gold-labelled immunosorbent assay.

We describe a new immunoassay for the detection of antibodies to the human immunodeficiency virus. The method is based on a silver enhanced gold-labelled immunosorbent assay (SEGLISA). Test sera are incubated in microtitre wells on which antigens have been coated. If present in the test sera, antibodies to the human immunodeficiency virus bind to the solid-phase antigens. Bound antibodies are quantitated with anti-human immunoglobulin labelled with gold. Positive specimens produce a faint pink deposit which is better visualised by silver enhancement which gives an intense black colour. The intensity of the colour is proportional to the bound antibody concentration. All the reagents are stable and the silver enhancement takes place under ambient light conditions. The assay has many of the advantages of micro enzyme-linked immunosorbent assays but does not suffer from the drawbacks associated with the use of an enzyme label. It requires fewer manipulations and is quicker to carry out than an equivalent enzyme-linked test. As the silver layer is permanent dried wells may be stored for future reading or checking.

AIDS Serodiagnosis↗
PubMed1980

Microscopic study of smooth silver-plated retention pins in amalgam.

A silver-plating technique was developed in an effort to produce good mechanical bonding characteristics between stainless steel pins and amalgam. Metallographic microscope and scanning electron microscope (SEM) studies were made to assess the presence, or otherwise, of such a bond between (a) the silver layer plating and the surface of the stainless steel pins, and (b) and silver plating and the amalgam. Unplated stainless steel and sterling silver pins were used as a control and as a comparison, respectively. A "rubbing" technique of condensation was devised closely adapt amalgam to the pins. It is concluded that there is strong evidence for the existence of a good bond between the plated pins and amalgam. The mechanical performance of the bond is discussed elsewhere.

Chemical Phenomena↗
PubMed1987

Experimental observation of silver and gold penetration into dental ceramic by means of a radiotracer technique.

A radiotracer technique was used to study silver and gold diffusion into dental porcelain under experimental conditions close to the real conditions in prosthetic laboratories for porcelain bakes. It was clearly shown that these non-oxidizable elements were able to diffuse into the ceramic as well as oxidizable ones. The penetration depth varied widely according to the element. The ratio DAg/DAu was about 10(3) around 850 degrees C. In contrast to gold, the silver diffusion rate was high enough to allow silver, from the metallic alloy, to be present at the external ceramic surface after diffusion into the ceramic. Hence, the greening of dental porcelains baked on silver-rich alloys could be explained mainly by a solid-state diffusion mechanism.

Chemical Phenomena↗
PubMed1989

In vitro caries-inhibitory properties of a silver cermet.

Recurrent caries is one of the primary causes of failure of dental restorations. One method for reducing the frequency and severity of this problem is the use of fluoride-releasing restorative materials. The glass-ionomer cements are a type of fluoride-releasing material. They have been used extensively in recent years for a variety of clinical applications. However, in comparison with other restorative materials such as amalgam and composite resins, glass ionomers have relatively poor physical properties. Sintering of silver particles to glass-ionomer powder is a means of improving these physical properties. The sintered material is called a silver-glass ionomer or silver cermet. This study examined the in vitro caries-inhibitory potential of a silver cement by means of two methods. First, long-term fluoride release was measured. Second, an artificial caries system was used for evaluation of caries inhibition by cerment restorations in extracted teeth. In comparison with a standard glass-ionomer restorative material, fluoride release from the cermet material was significantly less throughout a 12-month period. The results from the artificial caries system indicated that this decreased fluoride release corresponded with a lesser degree of caries inhibition. Lesions around cermet restorations in both enamel and root surfaces were significantly more severe than those around conventional glass-ionomer restorations. However, in comparison with amalgam and composite resin restorations, the cermet did have some cariostatic activity.

Cermet Cements↗
PubMed2002

Comparative analysis of an improved thioflavin-s stain, Gallyas silver stain, and immunohistochemistry for neurofibrillary tangle demonstration on the same sections.

An improved thioflavin-S stain, Gallyas silver stain, and two immunostainings were quantitatively compared for demonstration of neurofibrillary tangles (NFTs) on the same sections. Sections of hippocampal formation from seven cases of Alzheimer's disease (AD) were immunofluorescently stained with a commercially available polyclonal NFT antibody or a PHF-1 monoclonal antibody, followed by an improved thioflavin-S stain, and finally by Gallyas silver staining. The thioflavin-S method was improved by using a combination quenching method that removes background autofluorescence without remarkable tissue damage and by post-treatment with concentrated phosphate buffer, which minimizes photobleaching. PHF-1 or NFT immunostaining is much less sensitive than the improved thioflavin-S staining and Gallyas silver staining, particularly in the transentorhinal region. Moreover PHF-1 immunoreactivity varied greatly among AD individuals. Thioflavin-S staining and Gallyas silver staining show almost the same sensitivity in NFT demonstration, but only the former depends on the secondary protein structure of NFTs. This study suggests that the improved thioflavin-S staining is a simple, sensitive, and consistent method for demonstration of neurofibrillary pathology.

Aged↗
PubMed1978

Medichrome film as an alternative to silver-free recording systems.

A shortage of silver is forcing film manufacturers to lower the silver content of radiographic films. No further lowering seems possible without film quality being adversely affected. Various ways to solve the silver problem in the future are discussed and colour radiography is regarded as one solution since it makes possible a high degree of immediate recovery of silver. The feasibility and proper use of the only colour film available, Medichrome, is discussed. Suitable screens in order to compensate for the low sensitivity of the film without loss of image quality and a strong light source containing a monochromatic sodium lamp for inspection of dense areas are recommended.

Radiography↗
PubMed1994

In vitro evaluation of the antimicrobial efficacy and biocompatibility of a silver-coated central venous catheter.

Central venous catheter infection presents an important problem in modern medicine, leading sometimes to a life-threatening situation for the patient as well as contributing to prolonged hospital stay and to an increase in costs. We have evaluated the in vitro biocompatibility and antimicrobial activity of a silver-coated polyurethane catheter designed for use as a colonization-resistant, antiinfective catheter. Due to a comparatively low silver release, the catheter performed well in cell toxicity and blood compatibility tests as well as in acute toxicity tests done with mice. The antimicrobial activity was tested in stationary and dynamic bacterial adherence experiments using S. epidermidis, E. coli and P. aeruginosa as test strains. The silver-coated polyurethane catheter showed good ability to prevent microbial colonization of the catheter surface. Currently a clinical trial of the silver-coated catheter is under investigation.

Animals↗
PubMed1985

Silver amplification of mercury sulfide and selenide: a histochemical method for light and electron microscopic localization of mercury in tissue.

A method for light and electron microscopic demonstration of mercury sulfides and mercury selenides in mammalian tissue is presented. Silver ions adhering to the surface of submicroscopic traces of mercury sulfides or selenides in the tissue are reduced to metallic silver by hydroquinone. Physical development thereupon renders deposits of mercury sulfides or mercury selenide visible as spheres of solid silver. Examples of localization of mercury in the central nervous system and various organs from animals exposed to mercury chloride or methyl mercury chloride with or without additional sodium selenide treatment are presented. Selenium treatment results in a considerable increase in the amount of mercury that can be made visible by silver amplification. After mercury chloride treatment, most of the mercury is localized in lysosomes and is only rarely seen in secretory granules. After simultaneous selenium treatment, mercury is also found in nuclei of proximal tubule cells in the kidney and in macrophages. The "sulfide-osmium" method for ultrastructural localization of mercury suggested by Silberberg, Lawrence, and Leider (Arch Environ Health 19:7, 1969) and the light microscopic method using a photographic emulsion suggested by Umeda, Saito, and Saito (Jpn J Exp Med 39:17, 1969) have been experimentally analyzed and commented on.

Animals↗
PubMed1985

Ultrastructural analysis of central serotoninergic neurons immunolabeled by silver-gold-intensified diaminobenzidine chromogen. Completion of immunocytochemistry with X-ray microanalysis.

Serotonin immunoreactive structures of the rat central nervous system (CNS) were detected by the recently developed silver-intensified peroxidase-antiperoxidase complex (SI-PAP) method at both the light and electron microscopic levels. The silver postintensification of the diaminobenzidine (DAB) chromogen increased the sensitivity of the original PAP method, resulting in a very Golgi-like appearance of serotonin-immunopositive neuronal elements. The metallic silver and gold deposited onto DAB-labeled organelles, filling out the whole immunoreactive neuron, assures the easy tracing of thin neuronal processes far from the cell body. At the ultrastructural level, metallic grains were seen over immunolabeled structures only, proving the specificity of the silver method. In neurons of the dorsal raphe nucleus, free ribosomes, endoplasmic reticulum, and granules (80-100 nm in diameter) were labeled. Immunoreactive, e.g., serotoninergic, dendrites were seen to receive afferent terminals. The increased electron density of the intensified immunolabel facilitates the ultrastructural recognition of even weakly labeled profiles, while its metallic components (Ag and Au) provide a base for X-ray analysis of the immunolabeled biological specimen.

3,3'-Diaminobenzidine↗