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PubMed2006

InterGard silver bifurcated graft: features and results of a multicenter clinical study.

OBJECTIVES: Recent research in vascular surgery has focused on development of infection-resistant prosthetic grafts. This article describes the results of a multicenter study to evaluate safety, patency, and infection rates after implantation of the InterGard Silver bifurcated polyester graft coated with collagen and silver. METHODS: Between October 2000 and February 2002, 289 consecutive patients were implanted with a collagen and silver acetate-coated polyester bifurcated graft at 16 French vascular surgery centers. Mean patient age was 65.3 +/- 10.9 years. The indication for prosthetic bypass was aortic aneurysm in 160 patients (55.4%) and symptomatic aortoiliac occlusive disease in 129 (44.6%). All but four patients received prophylactic antibiotic therapy. Patency was assessed at 30 days, 1 year, 2 years, and 3 years, primarily by duplex scan. RESULTS: Two patients (0.7%) died during the first 30 days. Median duration of hospitalization was 11 days. The Kaplan-Meier survival rate at 3 years was 85.7% +/- 4.1%. Primary and secondary patency rates at 3 years were 94.9% +/- 2.6% and 97.5% +/- 1.8%. Thrombectomy was performed successfully in seven patients, and a major amputation was required in two patients with patent grafts. Postoperative complications, including 39 nosocomial infections, were observed in 107 patients (37.0%). Eleven patients presented with 12 wound infections that were classified Szilagyi grade I in eight cases, grade II in two cases, and grade III with graft infection in two cases (0.7%). Among the 149 patients undergoing aortofemoral bypass, eight (5.4%) presented with wound infection, including two graft infections (1.3%). Among the 140 patients undergoing aortoiliac bypass, only three patients (2.1%) presented wound infection and none with graft infection (P = .15). Three (16.7%) of 18 patients who had undergone previous femoral revascularization and eight (3%) of 271 patients without previous femoral revascularization presented with wound infection. This difference was statistically significant (P = .03), with a relative risk of 5.6 (95% confidence interval [CI], 1.6 to 19.5). Five (11.9%) of 42 diabetic patients and six (2.4%) of 247 nondiabetic patients presented with wound infection. This difference was also statistically significant (P = .01), with a relative risk of 3.4 (95% CI, 1.7 to 6.9). Lymphorrhea or lymphocele developed in the groin of 25 patients (8.6%) with negative culture. CONCLUSION: This multicenter prospective study shows that the InterGard Silver graft is safe with no side effects. The primary patency rate was excellent, and the graft infection rate was low, despite a high incidence of nosocomial infections.

Aged↗
PubMed1999

The silver sorption layer in dental composites: three year results.

OBJECTIVES: The purpose of this investigation was to observe the behaviour of a recently discovered silver sorption layer in seven dental composites for three years. METHODS: Rectangular block testpieces (3.0 x 2.5 x 2.5 mm) of seven resin composites were fabricated and the resin rich layer removed from one surface by grinding on silica carbide paper. The testpieces were immersed in aqueous AgNO3 (3 mol/l). After 26, 42, 90, 180, 360, 540, 720 and 1085 days, respectively, nine specimens of each material were removed to measure the depth of silver stain in the different composites. RESULTS: The depth of silver stain continued to increase at a rate proportional to (time)0.5. After three years, five homogeneous subsets [HS] were distinguished for the resin rich surface [HS1] Occlusin (stain depth = 45.6 microns); [HS2] Clearfil (117.8 microns), [HS3] Heliomolar (145.6 microns), Concise (148.8 microns), P-30 (168.9 microns); [HS4] Silux (243.3 microns); [HS5] Profile-TLC (446.7 microns). For the ground surface, the materials were in similar subsets but the depth of stain was less. Different coloured layers were seen within the sorption layer in some materials. SIGNIFICANCE: The linear relationship between the depth of stain and (time)0.5 indicate that the mechanism controlling the sorption is Case 1 (Fickian) diffusion. The different depths in the individual materials may indicate differences in the segmental mobility of the polymer chains and free space within the resin phase of the composites. If the silver sorption layer marks the extent of water penetration, then the results show different depth distributions for individual composites.

Absorption↗
PubMed1998

Physiological response of juvenile rainbow trout to chronic low level exposures of waterborne silver.

The physiological effects of chronic exposure to AgNO3 in moderately hard freshwater were investigated in juvenile rainbow trout (Oncorhynchus mykiss Walbaum). Two separate 28-day exposures were performed at silver concentrations of 0.5 and 2.0 micrograms/L in flowing Hamilton dechlorinated tap water. Exposure to 0.5 microgram/L Ag resulted in a slight increase (approximately 14.9%) in food consumption, whereas growth rates remained unaltered. Both plasma Na+ and Cl- levels were significantly decreased by 11.8% and 9.3%, respectively at day 16 of the exposure. Hepatic Ag concentrations were elevated approximately 4-fold in 0.5 microgram/L Ag-exposed fish. However, no significant increases in liver metallothionein (MT) concentrations were noted. No mortalities were observed during this 28-day exposure. In comparison, chronic exposure to 2.0 micrograms/L Ag resulted in a 28.8% decrease in food consumption and a 43.0% reduction in growth rate. Plasma [Na+] was decreased by 18.3%, whereas plasma [Cl-] was reduced by 12.2% at day 7. At both concentrations of silver, plasma ion concentrations appeared to recover thereafter. Silver accumulated steadily in the liver up until day 15 when concentrations were 39.7 micrograms/g wet weight (285-fold increase) above control levels. In addition, MT levels were increased by 81.2% at day 7. Silver exposure at 2.0 micrograms/L resulted in approximately 15.0% mortality over the 28-day period.

Animals↗
PubMed2003

Vibrational spectra of 1-methyluracilate complex with silver(I) and theoretical studies of the 1-MeU anion.

The FT-Raman and FT-infrared spectra of (1-methyluracilato)silver, [Ag(C(5)H(5)N(2)O(2))] in the solid state have been studied. The complex is a polymer in which one silver ion is linearly bonded to two 1-MeU ligands through the deprotonated N(3) sites and another silver ion is tetrahedrally coordinated to the four 1-MeU ligands through the O2 and O4 carbonyl oxygen atoms. The harmonic vibrational frequencies, infrared intensities and Raman scattering activities of the N(3)-deprotonated 1-methyluracilate anion have been calculated using density functional (B3LYP) and ab initio (HF and MP2) methods with the 6-31G(d,p) and 6-31++G(df,pd) basis sets. The calculated potential energy distribution (PED) for the 1-MeU anion has proved to be of great help in assigning the spectra of the title complex. It can be concluded that the two strong Raman bands at 1263 and 796 cm(-1) are diagnostic for the N3-deprotonation of the 1-methyluracilate ring and complexation with silver ion. The linear N-Ag-N stretching vibrations are assigned to the bands at 448 and 362 cm(-1) (IR) and 453, 362 cm(-1) (Raman). The Ag-O stretching vibrations are assigned to the bands in the range of 280-250 cm(-1).

Anions↗
PubMed1991

Staining plant cells with silver. I. The salt-nylon technique.

A technique is described for selectively silver staining nucleoli, active nucleolus organizers, nucleolar material attached to chromosomes, kinetochores, synaptonemal complexes, and chromosome cores in plant cells. The technique, called salt-nylon silver staining, involves spreading cells on glass slides, treating the cells with a solution of saline sodium citrate, and incubating the cells in a silver nitrate solution covered with nylon screen. Selected variables important for achieving reliable silver staining are considered.

Allium↗
PubMed2001

[A comparison of SERS of positive and negative nano-silver adsorbing cation and anion molecule].

A study on the negative charge colloid of nano-silver particles with anion and cation molecules has been done. The results of the experiment show that the negative charge colloid of nano-silver particle has no SERS effect when anion molecule adsorbed on its surface. While the cation molecule in adsorbed on its surface the SERS effect is enhanced. The SERS effects are just opposite when the two molecules separately adsorbed on the surface of the positive colloid of nano-silver particles. The paper hypothesizes that strong SERS effect can be got by using proper colloid of nano-silver particles. It is practical to develop the use of SERS.

Adsorption↗
PubMed2004

[Study on spectrophotometric determination of silver(I) with 2-(2-quinolinylazo)-1,5-dihydroxidebenzene].

The color reaction of silver(I) with 2-(2-quinolinylazo)-1,5-dihydroxidebenzene (QADHB) and the solid phase extraction of the colored chelate with Waters Sep-Park C18 cartridge were developed. In the presence of pH = 5.0 sodium citrate-sodium hydroxide buffer solution and sodium dodecyl sulfonate (SDS) medium, QADHB can reacts with silver to form a chelate of a molar ratio 1:2 (silver to QADHB). This chelate can be enriched by the solid phase extraction with Waters Sep-Park C18 cartridge. The retained chelate can be eluted from cartridge with ethanol. In ethanol medium, the molar absorptivity is 6.99 x 10(4) L x mol(-1) x cm(-1) at 550 nm. Beer's law is obeyed in the range of 0-1.2 microg x mL(-1). This method can be applied to the determination of silver in water with satisfactory results.

Benzene↗
PubMed1983

Chemical preparation of the eye in ophthalmic surgery. II. Effectiveness of mild silver protein solution.

Although a mild silver protein solution (Argyrol) has been used for a number of years and is still used by many ophthalmic surgeons, its efficiency as an antibacterial agent on the conjunctiva has not been scientifically evaluated as part of the preoperative chemical preparation of the eye. We studied the effectiveness of a mild silver protein solution on the conjunctival flora of 32 patients in a masked fashion. By bacteriologic analysis, the mild silver protein solution was found to be no more effective in reducing the number of species and colonies in the treated eye than in the untreated eye. While the mild silver protein solution does stain mucus and other debris on the eye to facilitate irrigation, this study did not demonstrate a significant bactericidal effect.

Conjunctiva↗
PubMed1985

Endolymphatic hydrops in guinea pigs after cauterizing the sac with silver nitrate.

There have been several reports of perisaccular fibrosis of the endolymphatic sac in some autopsied cases of Meniere's disease. We attempted to initiate perisaccular fibrosis of the sac in guinea pigs by injecting a small amount of 10% silver nitrate solution that cauterizes the tissue readily to produce scar, ie, fibrosis. Ninety-nine guinea pigs out of 108 (92%) that were treated with silver nitrate showed the endolymphatic hydrops in varied extent, from slight to profound. The extent of hydrops might depend on the extent of destruction of the sac following the cauterization. The lumen of the sac was sometimes occupied with dense fibrous connective tissue with deposition of black-silver particles in it. The silver nitrate injection method is an easy way to produce endolymphatic hydrops in guinea pigs.

Animals↗
PubMed1995

Antimicrobial activity of silastic tympanostomy tubes impregnated with silver oxide. A double-blind randomized multicenter trial.

OBJECTIVE: To test the null hypothesis that impregnation of tympanostomy tubes with silver oxide did not alter the rate of postintubation otorrhea. DESIGN: Multicenter, double-blind, randomized clinical trial. OUTCOME MEASURE: Rates of postoperative otorrhea during a 1-year study in ears implanted with Silastic tubes compared with contralateral, identical tubes impregnated with silver oxide. SETTING AND PARTICIPANTS: Eight sites in the United States, 125 children aged 1.5 months to 12 years who had bilateral otitis media with effusion or bilateral recurrent acute otitis media. RESULTS: The overall incidence of postoperative otorrhea was 9.78% in the control ears and 5.08% in the ears with silver oxide-impregnated tubes (P = .01), but no effect was seen during the immediate postoperative period. Granulation tissue was seen adjacent to the tube during two visits in the ears with standard tubes (0.54%) and during two visits in the ears with experimental tubes (0.53%); cholesteatomas did not occur in either group. CONCLUSION: Silastic tubes impregnated with silver oxide seem to diminish the incidence of postoperative otorrhea in ears requiring long-term ventilation.

Anti-Infective Agents↗
PubMed1979

Pharmacology of sulfadiazine silver. Its attachment to burned human and rat skin and studies of gastrointestinal absorption and extension.

The attachment of Ag110-labeled sulfadiazine silver (AgSU) to the burn wound of humans and full and partial thickness scald burns of rats was studied over time. The duration of Ag adherence to burned skin and the absorption and organ distribution of ingested AgSU was studied. Peak attachment to human burns was 1% of the administered dose in 24 hours. Rat wounds showed greater attachment. Dissections of the wounds showed 81% to 98.7% of this attachment to be in the most superficial layers of cells and no silver was observed in organs of surface-treated animals. Duration of attachment after one application was until wound slough with percent attachment dropping from 5% to 1.7% over that time. Oral ingestion resulted in substantial silver deposition, particularly in liver and lungs. Clearance occurs in three weeks. The basic function of AgSU may be through the slow release of silver into the superficial wound environment.

Animals↗
PubMed1998

Combined characterization of composite tabular silver halide microcrystals by cryo-EFTEM/EELS and cryo-STEM/EDX techniques.

The combination of cryo-energy filtering transmission electron microscopy (EFTEM)/electron spectroscopic diffraction (ESD)/electron energy-loss spectroscopy (EELS) and cryo-energy-dispersive X-ray (EDX) analysis in the scanning transmission (STEM) and scanning (SEM) modes was applied for the characterization of composite tabular Ag(Br,I) microcrystals. A low-loss fine structure in EEL spectra between 4 and 26 eV was attributed to excitons and plasmons possibly superimposed with interband transitions and many-electron effects. The contrast tuning under the energy-filtering in the low-loss region was used to image the crystal morphology, defect structure (random dislocations and ¿111¿ stacking faults) and bend and edge contours as well as electron excitations in the microcrystals. Sharp extra reflections at commensurate positions in between the main Bragg reflections and diffuse honeycomb contours in ESD patterns of the microcrystals taken near the [111] zone were assigned to the number of defects in the shell region parallel to the grain edges and polyhedral clusters of interstitial silver cations, respectively. The imaginary part of the energy-loss function, Im (-1/epsilon), and the real and imaginary parts, epsilon1 and epsilon2, of the dielectric permittivity were determined by means of a Kramers-Kronig analysis. An assignment of exciton peaks based on calculations of electronic band structure of silver bromide is proposed. Inner-shell excitation bands of silver halide were detected in line with EDX-analyses. The energy-loss near-edge structure (ELNES) of the AgM4,5-edge governed by spin-orbital splitting between the 3d3/2- and 3d5/2-states has been evaluated. Combined silver and halide distributions were obtained by a three-window method (EFTEM) and by EDX/STEM including area mapping and line profiling of iodide.

Bromides↗
PubMed2001

A new silver staining apparatus and procedure for matrix-assisted laser desorption/ionization-time of flight analysis of proteins after two-dimensional electrophoresis.

We report on a new silver stain especially developed for staining large gels (25 cm x 20 cm) from the Hoefer ISO-DALT system for matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis of proteins. The staining protocol can be summarized as follows: the gels are sensitised in tetrathionate/potassium acetate solution and washed several times in distilled water. After impregnation with silver nitrate, the silver is reduced in the presence of potassium carbonate, thiosulphate and formaldehyde. The staining procedure is stopped with Tris/acetate after which the gels are rinsed and stored in water before spot picking for MALDI-TOF analysis is performed. This protocol has several advantages over existing ones. The gels are stained in a new apparatus that reduces gel handling to a minimum thus also reducing the contamination with keratins to a minimum. The development times in potassium carbonate are very long (up to 40 min) thus improving batch-to-batch reproducibility. Only the surface of the proteins is stained and the silver can be oxidized, thereafter MALDI-TOF can be performed with protein loads as little as 100 micrograms per gel.

Cell Line↗
PubMed2002

Proteomic analysis of human biopsy samples by single two-dimensional electrophoresis: Coomassie, silver, mass spectrometry, and Western blotting.

Proteomic analysis of myocardial tissue from patient populations is critical to our understanding of cardiac disease, but has been limited until now by the small size of biopsies (approximately 20-50 microg), and complicated by the difference in relative abundance of contractile proteins over other cellular components. Here we describe an approach to analysis of myocardial biopsies from patients undergoing coronary artery bypass surgery. First, individual biopsies are selectively extracted, producing subfractions that correspond to the contractile proteins and the cytosolic proteins. Two-dimensional electrophoresis separated proteins are detected by first staining with Coomassie blue then silver, to permit a wider range of accurate quantification. Western blotting of two-dimensional separated samples, to validate peptide mass fingerprinting data, previously required additional gel separations for transfer since staining protocols are not compatible with transfer to membranes or immunoblotting. An existing silver destaining protocol was adapted to allow removal of silver from a whole gel, followed by transfer and Western blotting. An existing Coomassie blue removal protocol was also adapted to permit Western blotting of gels stained with Coomassie blue and silver. Together, these techniques permit peptide mass fingerprinting concurrent with Western blotting of a single protein spot from a single biopsy, eliminating the need for repeated gel separations, and improving spot alignment between immunoblots and stained gels. In the end, this approach may allow a more complete characterization of protein changes in small human biopsies, and also reduce the number of repeated gel separations necessary for a standard proteomic analysis.

Animals↗
PubMed1979

"Silver dust"--a tool to study growth interrelationships between bone, periosteum and muscle.

A cylinder of gelatin containing silver spongy granules was placed in and lay within the masseter muscle, the periosteum, and the mandible, and terminated in the medial pterygoid muscle of young (3 month-old) growing miniature pigs. On the basis of an animal sacrificed one week after placement of the cylinder, it was found that the suspending gelatin was removed by cellular activity. Nine months later the remaining animals were sacrificed. Periodic X-rays were taken during the course of the experiment. After sacrifice, the mandible and associated tissues were histologically examined. The results of this study suggest that the silver granules in the muscles maintained their location during growth; the silver granules in the mandible moved forward with mandibular growth. "Slippage" appeared to occur external to the fibrous layer of the periosteum; the site of movement was revealed by the trail of the silver granules. The described method should prove of value in studying the growth interrelationships between bone, periosteum, and muscle.

Animals↗
PubMed2003

Fluorescence properties of labeled proteins near silver colloid surfaces.

The fluorescence properties of a monolayer of labeled avidin molecules were studied near silver island films. We first adsorbed a monolayer of biotinylated-BSA as a base that was used to capture labeled avidin molecules. For labeled avidin on silver island films, we observed an increase of the fluorescence intensity of between 18 and 80 with one-photon excitation and up to several hundredfold or larger with two-photon excitation. The probes were moderately more photostable in the presence of silver islands. There was also a dramatic decrease in the lifetimes with the amplitude-weighted values decreasing from 7- to 35-fold. The data suggest that these spectral changes are due to both increased rates of excitation near the metallic particles and increases in the rates of radiative decay. Because these silver island surfaces are very heterogeneous, we are hopeful that larger increases in intensity and photostability can be obtained for probes situated at an optimal distance from the ideal island surfaces.

Avidin↗
PubMed2004

Effect of silver nanoparticles on the electron transfer reactivity and the catalytic activity of myoglobin.

Silver nanoparticles (11+/-1.5 nm) could greatly enhance the electron-transfer reactivity of myoglobin (Mb) and its catalytic ability toward hydrogen peroxide (H2O2). Direct fast electron transfer between Mb and a pyrolytic graphite (PG) electrode was achieved, and a pair of well-defined, quasi-reversible redox peaks was obtained. The cathodic and anodic peaks were located at -329 and -281 mV, respectively. Meanwhile, the catalytic ability of the protein toward the reduction of H2O2 was also studied, and a H2O2 biosensor was subsequently fabricated. Its detection limit was 1.0 x 10(-6) M with a sensitivity of 0.0205 microA per microM of H2O2. The apparent Michaelis-Menten constant was calculated to be 1303 muM. Flocculation assay showed that the protein maintained plasmon layers surrounding the surface of silver nanoparticles and avoided silver-nanoparticle aggregation. On the other hand, UV-visible spectroscopy studies revealed that silver nanoparticles could induce a small change of the heme-group environment of the protein; this contributed to the enhancement of the electron-transfer reactivity and the catalytic activity.

Biosensing Techniques↗
PubMed2005

Shape-controlled synthesis of metal nanostructures: the case of silver.

The concept of shape-controlled synthesis is discussed by investigating the growth mechanisms for silver nanocubes, nanowires, and nanospheres produced through a polymer-mediated polyol process. Experimental parameters, such as the concentration of AgNO(3) (the precursor to silver), the molar ratio between poly(vinylpyrrolidone) (PVP, the capping agent) and AgNO(3), and the strength of chemical interaction between PVP and various crystallographic planes of silver, were found to determine the crystallinity of seeds (e.g., single crystal versus decahedral multiply twinned particles). In turn, the crystallinity of a seed and the extent of the PVP coverage on the seed were both instrumental in controlling the morphology of final product. The ability to generate silver nanostructures with well-defined morphologies provides a great opportunity to experimentally and systematically study the relationship between their properties and geometric shapes.

Citrates↗