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At least 721 records · Page 40Linked to original sources
PubMed1983

Mechanisms of in vitro sensitivity to sulfadiazine silver.

Sulfonamide-resistant organisms have been reported as a frequent consequence of the clinical use of sulfadiazine silver. At this burn center, sulfonamide resistance occurred in more than 80% of gram-negative isolates. We tested the requirement for the individual antimicrobial activities of sulfadiazine and silver for the vitro activity of sulfadiazine silver. The sulfadiazine component is not necessary for in vitro sensitivity. In vitro sensitivity to sulfadiazine silver does not consistently predict the presence of therapeutic activity in Pseudomonas aeruginosa-infected rats with burns. We describe an example of a transferable multiple-antibiotic resistance plasmid that contains selectable sulfonamide resistance. The use of sulfadiazine silver can, therefore, lead to the selection of organisms that are resistant not only to sulfonamides but to antibiotics of clinical consequence, and this possible risk must be considered in electing to use the agent.

Animals↗
PubMed2000

Prevention of pin track infection in external fixation with silver coated pins: clinical and microbiological results.

Pin tract infection is a frequent complication of external fixation; according to literature its frequency ranges from 2-30%. The recent introduction of silver coating of polymeric materials was found to decrease bacterial adhesion; its clinical use with Foley catheters and central venous catheters led to significant results. To verify the ability of the same silver coating to decrease the bacterial colonization on external fixation screws, a prospective randomized study was carried out on 24 male patients; a total of 106 screws were implanted in the lower limb to fix femoral or tibial diaphyseal fractures: 50 were coated with silver and 56 were commercially available stainless steel screws. Although the coated screws resulted in a lower rate of positive cultures (30.0%) than the uncoated screws (42.9%), this difference was not statistically significant (p = 0.243). The clinical behavior of the coated screws did not differ from that of the uncoated ones. Furthermore, the implant of silver-coated screws resulted in a significant increase in the silver serum level. These results led us to consider it ethically unacceptable to continue this investigation.

Adolescent↗
PubMed2006

Silver based wound dressings and topical agents for treating diabetic foot ulcers.

BACKGROUND: Foot ulceration affects 15-20% of people with diabetes. It is a major precursor to amputation in this patient group, and early and appropriate treatment provides the greatest opportunity for healing. The use of silver for its antimicrobial properties has re-emerged, and modern wound dressings that release a sustained amount of free silver ions, are now widely used in wound management. OBJECTIVES: To evaluate the effects of silver-containing dressings and topical agents on infection rates and healing of diabetes related foot ulcers. SEARCH STRATEGY: Searches were made of the Cochrane Wounds Group Specialised Register (August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library Issue 3 2005) MEDLINE (1966 to October week 2 2004), EMBASE (1980 to October week 2 2004) and CINAHL (1982 to October week 2 2004). The Journal of Wound Care (Volume 12/13 Issues 1-10) was hand-searched. Manufacturers, researchers and local and international wound groups were contacted in order to identify unpublished trials. Web sites for wound groups and World Wide Wounds (www.worldwidewounds.com) were searched. SELECTION CRITERIA: Randomised controlled trials and non-randomised controlled clinical trials were considered for inclusion. Studies were included if they involved participants with Type 1 or Type 2 diabetes and related foot ulcers, met the requirements for randomisation, allocation and concealment where appropriate, and compared the intervention with a placebo or a sham dressing, an alternative non silver based dressing or no dressing, and reported outcomes that represent healing rate or infection. DATA COLLECTION AND ANALYSIS: Two authors independently evaluated the papers identified by the search strategy against the inclusion criteria but identified no trials eligible for inclusion in the review. It was not possible to perform planned subgroup and sensitivity analysis in the absence of data. In future, if eligible trials become available, a random effects model will be applied for meta-analysis in the presence of statistical heterogeneity (estimated using the I(2) statistic). Dichotomous outcomes will be reported as risk ratios with 95% confidence intervals (CI), and continuous outcomes as weighted mean differences (WMD) with 95% CI. Statistical significance will be set at P value < 0.05 for all outcomes and the magnitude of the effect will be estimated by calculating the number needed to treat (NNT) with 95% CI. MAIN RESULTS: No studies were identified that met with the inclusion criteria AUTHORS' CONCLUSIONS: Despite the widespread use of dressings and topical agents containing silver for the treatment of diabetic foot ulcers, no randomised trials or controlled clinical trials exist that evaluate their clinical effectiveness. Trials are needed to determine clinical and cost-effectiveness and long term outcomes including adverse events.

Administration, Topical↗
PubMed2003

Fluorescence spectral properties of cyanine dye labeled DNA near metallic silver particles.

Recent studies have demonstrated that silver metallic particles can increase the quantum yield and decrease the lifetimes of nearby fluorophores. These studies are extended to double stranded DNA oligomers labeled with N,N'-(dipropyl)-tetramethylindocarbocyanine (Cy3) or N,N-(dipropyl)-tetramethylindodicarbocyanine (Cy5). The proximity to silver particles increases the apparent quantum yields and decreases the lifetimes of the double helical DNA 23-mer labeled individually with Cy3 or Cy5. The decreased lifetimes are accompanied by apparently increased photostability of the labeled oligomers near silver particles. Because of spatial averaging across the sample these results are likely to significantly underestimate the effects of silver particles on labeled DNA localized at an optimal distance from the metallic surface. These results suggest that DNA arrays fabricated on substrates with silver particles can display increased sensitivity and photostability in the analysis of gene expression.

Base Sequence↗
PubMed2007

Topical delivery of silver nanoparticles promotes wound healing.

Wound healing is a complex process and has been the subject of intense research for a long time. The recent emergence of nanotechnology has provided a new therapeutic modality in silver nanoparticles for use in burn wounds. Nonetheless, the beneficial effects of silver nanoparticles on wound healing remain unknown. We investigated the wound-healing properties of silver nanoparticles in an animal model and found that rapid healing and improved cosmetic appearance occur in a dose-dependent manner. Furthermore, through quantitative PCR, immunohistochemistry, and proteomic studies, we showed that silver nanoparticles exert positive effects through their antimicrobial properties, reduction in wound inflammation, and modulation of fibrogenic cytokines. These results have given insight into the actions of silver and have provided a novel therapeutic direction for wound treatment in clinical practice.

Administration, Topical↗
PubMed2002

Catheter-related infection and thrombosis of the internal jugular vein in hematologic-oncologic patients undergoing chemotherapy: a prospective comparison of silver-coated and uncoated catheters.

BACKGROUND: Catheter-related venous thrombosis is one of the most frequent complications of central venous catheters (CVCs). This complication occurs in 4- 40% of patients with hematologic malignancies receiving conventional chemotherapy after placement of CVCs. METHODS: The objective of this prospective study was to assess whether a silver-coated CVC poses an additional risk in the development of catheter-related thrombosis in hematologic-oncologic patients. Patients were randomized to receive either silver-coated polyurethane catheters (BactiGuard; Metacot, Stockholm, Sweden) or uncoated standard polyurethane catheters (Cavatheter, Fresenius AG, Bad Homburg, Germany) for central venous access. Silver-coated catheters (n = 120) and standard catheters (n = 113) were inserted into the jugular vein in 233 consecutive patients. Variables that may be significant for the development of thrombosis were comparable in the two groups. After removal of the CVC, the patency of both jugularian veins internal as well as external was assessed with real-time ultrasound (Sonolayer-SAL-35A; Toshiba, Tokyo, Japan). RESULTS: Four of 233 patients (1.5%) were found to have venous thrombosis. Incomplete occlusion of the internal jugular vein occurred in 2 patients (0.75%, parietal thrombosis), and complete thrombosis, although clinically silent, was found in 2 patients (0.75%). There was no difference between patients with silver-coated and uncoated CVCs. CONCLUSIONS: The authors concluded that this novel silver-coated CVC does not cause a higher rate of central venous thrombosis compared with standard CVCs. The low overall incidence of central venous thrombosis might be attributed to the routine application of low-dose heparin in our patients during chemotherapeutic treatment.

Antineoplastic Agents↗
PubMed2005

Efficient and sensitive method of DNA silver staining in polyacrylamide gels.

DNA silver staining is widely used to detect DNA fragment in polyacrylamide gel with high sensitivity. Conventional procedures of the silver staining involve several steps, which take about 40 min to 2 h in total. To improve the efficiency of DNA silver staining, a more efficient protocol is developed in this study. The procedure comprises only four steps including impregnating, rinsing, developing, and stopping, and could be completed within 20 min. Nitric acid and ethanol in the silver-impregnation step of the new procedure eliminates the need for prior treatment of gels with a fixing solution and following rinse prior to impregnation with silver. The procedure has high sensitivity and long storage lifetime. The minimum detectable mass of DNA is 0.44 and 3.5 ng in denaturing and nondenaturing polyacrylamide gel, respectively.

Acrylic Resins↗
PubMed2006

Construction of antibacterial multilayer films containing nanosilver via layer-by-layer assembly of heparin and chitosan-silver ions complex.

Antibacterial multilayer films containing nanosilver were prepared via layer-by-layer fashion. PET film was aminolyzed with 1,6-hexanediamine to introduce amino groups on PET film surface; chitosan-silver nitrate complex and heparin were alternately deposited onto an aminolyzed PET film surface, and subsequently, the silver ions within the multilayer films were reduced with ascorbic acid to form silver nanoparticles. UV-visible spectroscopy and transmission electron microscopy confirmed the formation of well-dispersed nanosilver particles with sizes (10-40 nm) that depended on the initial concentration of silver ions in chitosan solution and the pH of ascorbic acid solution. The chitosan/heparin multilayer films were possessed of bactericidal effect on Escherichia coli (E. coli), and this antibacterial effect could be significantly enhanced by the incorporation of silver nanoparticles into the multilayer films. The multilayer films containing nanosilver were not only effective as antibacterial but also as anticoagulant coating. And cell toxicity evaluation suggested that the multilayer films containing nanosilver did not show any cytotoxicity. The multilayer films containing nanosilver may have good potentials for surface modification of medical devices, especially for cardiovascular implants.

Animals↗
PubMed2004

About the mechanism of interference of silver staining with peptide mass spectrometry.

The mechanism by which silver staining of proteins in polyacrylamide gels interferes with mass spectrometry of peptides produced by proteolysis has been investigated. It was demonstrated that this interference increases with time between silver staining and gel processing, although the silver image is constant. This suggested an important role of the formaldehyde used in silver staining development in this interference process. Consequently, a formaldehyde-free staining protocol has been devised, using carbohydrazide as the developing agent. This protocol showed much increased peptide coverage and retained the sensitivity of silver staining. These results were however obtained at the expense of an increased background in the stained gels and of a reduced staining homogeneity.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2002

Silver stain removal using H2O2 for enhanced peptide mass mapping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Hydrogen peroxide solutions are reported for the removal of silver stain from proteins isolated in polyacrylamide gels. Removal of silver stain prior to in-gel digestion is shown to enhance sensitivity and sequence coverage of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) peptide mass maps. The rate of silver removal using H2O2 is influenced by H2O2 concentration and increases with increasing pH. The presence of complexation reagents such as ammonia from mass spectrometry compatible ammonium bicarbonate solutions enhances the efficiency and speed of H2O2-mediated silver removal. H2O2-mediated silver removal using the described procedure does not appear to have any detrimental effects on proteins but is observed to produce a slightly elevated level of methionine oxidization over that usually observed in in-gel tryptic digestion.

Bicarbonates↗
PubMed2003

A simple method for fabrication of silver-coated sheathless electrospray emitters.

A simple and time-saving procedure is proposed for preparing a silver-coated fused-silica capillary tip. The tapered capillary tip was coated with silver using an acrylic-based silver conductive pen. The fabrication of a silver-coated fused-silica capillary tip takes less than 5 minutes. The silver-coated fused-silica capillary tip is rugged and durable for sheathless capillary electrophoresis/electrospray mass spectrometry and also for microspray applications.

Animals↗
PubMed1993

Silver-enhanced copper staining of protein blots.

Copper staining of protein blots has previously been shown to detect proteins rapidly, quantitatively, and sensitively. The sensitivity of this assay can now be enhanced nearly 10-fold with an additional step of silver staining. The silver-enhanced assay retains many of the virtues of copper staining, including a quantitative optical response with the amount of adsorbed protein, low variation between proteins, and reversibility. In addition, both copper staining and silver-enhanced copper staining do not detect nucleic acid, thus allowing for selective measurement of nucleic acid binding proteins or protein contamination in nucleic acid preparations. Silver-enhancement requires only a 5-min incubation with a single reagent. Since copper staining is performed first, it can be used to determine if the greater sensitivity provided by silver enhancement is desirable. For quantitation, an inexpensive reflectance scanning densitometer utilizing optical scanners and NIH Image is described.

Albumins↗
PubMed2002

Radiative decay engineering. 2. Effects of Silver Island films on fluorescence intensity, lifetimes, and resonance energy transfer.

Metallic surfaces can have unusual effects on fluorophores such as increasing or decreasing the rates of radiative decay and the rates of resonance energy transfer (RET). In the present article we describe the effects of metallic silver island films on the emission spectra, lifetimes, and energy transfer for several fluorophores. The fluorophores are not covalently coupled to the silver islands so that there are a range of fluorophore-to-metal distances. We show that proximity of fluorophores to the silver islands results in increased fluorescence intensity, with the largest enhancement for the lowest-quantum-yield fluorophores. Importantly, the metal-induced increases in intensity are accompanied by decreased lifetimes and increased photostability. These effects demonstrate that the silver islands have increased the radiative decay rates of the fluorophore. For solvent-sensitive fluorophores the emission spectra shifted to shorted wavelengths in the presence of the silver islands, which is consistent with a decrease of the apparent lifetime for fluorophores near the metal islands. We also observed an increased intensity and blue spectral shift for the protein human glyoxalase, which displays a low quantum yield for its intrinsic tryptophan emission. In this case the blue shift is thought to be due to increased emission from a buried low-quantum-yield tryptophan residue. Increased intensities were also observed for the intrinsic emission of the nucleic acid bases adenine and thymine and for single-stranded 15-mers poly(T) and poly(C). And finally, we observed increased RET for donors and acceptors in solution and when bound to double-helical DNA. These results demonstrate that metallic particles can be used to modify the emission from intrinsic and extrinsic fluorophores in biochemical systems.

Adenine↗
PubMed1999

Elasticity of mutant myosin subfragment-1 arranged on a functional silver surface.

Elasticity of a two-dimensionally arranged myosin subfragment-1 (S1) was measured by using a surface forces apparatus. To prepare a two-dimensionally arranged S1-monolayer on a functionalized silver surface, we used genetically engineered Dictyostelium S1 molecules. A highly reactive cysteine residue was fused to the COOH-terminus using the recombinant DNA method. On the other hand, the maleimide groups was self-assembled onto a silver surface. Then the mutant S1 molecules were chemically bound to the functionalized silver surface at its COOH-terminus. This arrangement technique was necessary in order to create a stable S1-monolayer by chemical bond formation onto the silver surface. The occupied area of the single S1 on the silver surface was about 110 nm(2). In the interaction between the S1-monolayer and mica surfaces in aqueous solution, a long-range attractive force was observed. The elastic constants (stiffness and Young's modulus) of myosin S1 were evaluated from force-distance profiles in aqueous solution, using the Hertz theory. We found that the stiffness (or spring constant) and Young's modulus of S1 in the absence of nucleotide are 4.4 +/- 1.0 pN/nm and 0.71 +/- 0.16 GPa, respectively.

Aluminum Silicates↗
PubMed1999

ATP-dependent silver transport across the basolateral membrane of rainbow trout gills.

Silver has been shown to be extremely toxic to freshwater teleosts, acting to inhibit Na(+) uptake at the gills, due to the inactivation of branchial Na(+)/K(+)-ATPase activity. However, the gills are also a route by which silver may enter the fish. Therefore, this study focuses on the mechanism of transport of this nonessential metal across the basolateral membrane of the gill cell, using basolateral membrane vesicles (BLMV) prepared from the gills of freshwater rainbow trout. Uptake of silver by BLMV was via a carrier-mediated process, which was ATP-dependent, reached equilibium over time, and followed Michaelis-Menten kinetics, with maximal transport capacity (V(max)) of 14.3 +/- 5.5 (SE) nmol mg membrane protein(-1) min(-1) and an affinity (K(m)) of 62.6 +/- 43.7 microM, and was inhibited by 100 microM sodium orthovanadate (Na(3)VO(4)). The ionophore monensin (10 microM) released transported silver from the BLMV. Acylphosphate intermediates, of a 104 kDa size, were formed from the BLMV preparations in the presence of ATP plus Ag. These results demonstrate that there is a P-type ATPase present in the basolateral membrane of the gills of rainbow trout that can actively transport silver, a process which will remove this heavy metal from its site of toxic action, the gill.

Animals↗
PubMed1976

An improved technique for selective silver staining of nucleolar organizer regions in human chromosomes.

A reliable technique for staining human chromosomal nucleolar organizers (NOR's) with silver solutions is described. The NOR's can be selectively stained dark brown by silver solutions leaving the chromosome arms unstained and available for counterstaining with orcein or Giemsa dyes. Unequivocal identification of chromosome pairs bearing NOR's can be achieved using fluorescent banding techniques followed by silver staining. The silver staining procedure for NOR's was simplified and standardized through control of the chemical and physical conditions during silver impregnation and developing.

Chromosomes↗
PubMed1979

Pattern of activity of nucleolus organizers during spermatogenesis in mammals as analyzed by silver-staining.

Silver-staining in the nuclei and chromosomes of spermatogenesis of four species of mammals (Man, Mus musculus, Rattus norvegicus, and Cavia cobaya) was investigated qualitatively and quantitatively. These species show a very similar pattern of activity of the nucleolus organizer regions (NORs) during the various stages of spermatogenesis. Silver precipitates are detectable in growing spermatogonia and up until the pachytene stage of meiotic prophase. During the meiotic metaphases I and II and during interkinesis silver-stainability disappears completely. A resumpton of silver-stainability occurs in round spermatids indicating a postmeiotic reactivation of NORs. This process does not persist beyond the early elongation phase. The quantitative determination of the silver-covered areas in relation to the total nuclear areas reveals minor differences between the species investigated with regard to the times and extents of maximum activation. The known localizations of the NORs in the karyotypes of the species investigated was confirmed using metaphase-preparations derived from somatic tissues.

Animals↗
PubMed1978

Rapid identification of chromosomes carrying silver-stained nucleolus-organizing regions: application to case of 21/21 Robertsonian translocation.

The use of a combination of transmitted light and epiluminescence after silver and fluorescent staining of chromosome preparations makes it possible to achieve simultaneous visualization of silver-stained NORs and flourescent chromosomes. This technique permits exact localization of silver precipitates on normal and BrdU-substituted chromosomes. After previous silver impregnation, fluorescent staining by actinomycin-daunomycin-DAPI was used to induce a banding pattern that enables identification of specific chromosomes while observing silver-stained NORs at the same time. Application of this method to a Down's syndrome patient revealed a 21/21 Robertsonian translocation with NOR'S eliminated.

Cell Nucleolus↗