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At least 91 records · Page 5Linked to original sources
PubMed1998

Effect of a silver device in preventing catheter-related infections in peritoneal dialysis patients: silver ring prophylaxis at the catheter exit study.

Catheter-related infections remain a significant cause of method failure in chronic peritoneal dialysis (PD) therapy. Given the increasing antibiotic resistance, such nonpharmacological strategies as local silver devices attract more interest. To establish whether a silver ring device (designed by Grosse-Siestrup in 1992) mounted onto the PD catheter and placed at the exit site at skin level is effective in preventing exit-site and other catheter-related infections, a prospective 12-month, multicenter, controlled study stratified by diabetes status was conducted. The study subjects were assessed by an extensive structured inventory, including a broad spectrum of control variables, such as age, body mass index (BMI), Staphylococcus aureus carrier status, catheter features, mode and quality of PD therapy, comorbidity, and psychosocial rehabilitation. Ten experienced German outpatient dialysis centers (seven adult, three pediatric) participated in the trial. All eligible patients (n=195) from the study area without catheter-related infections during the ascertainment period were included (incidental subjects undergoing PD therapy for at least 3 months). The main outcome measures were the occurrence of first exit-site infections (primary study end point), sinus tract/tunnel infection, and peritonitis. Ninety-seven patients were assigned to the silver ring and 98 patients to the control group. Baseline characteristics of age, sex, proportion of pediatric and incidental patients, S aureus carrier status, and other variables were similar in both groups. The incidence of infections in the silver ring group versus the control group was as follows: 23 of 97 versus 16 of 98 patients had exit-site infections, 12 of 97 versus 12 of 98 patients had sinus tract/tunnel infections, 16 of 97 versus 18 of 98 patients had peritonitis, respectively. Kaplan-Meier analysis for the probability of an infection-free interval showed no statistical difference (log-rank test) between the two groups. Displacement of the silver ring contributed to study termination in 6% of the study group patients, including two patients with catheter loss. Univariate analysis and multiple logistic regression identified younger age (<50 years), low serum albumin level (<35 g/L), number of previously placed PD catheters, short cuff-exit distance (<2 cm), and S aureus nasal carriage as risk factors for the development of exit-site infections. In conclusion, our study does not show any benefit of the silver ring in preventing catheter-related infections in PD patients. Thus, prevention of infection-related method failure in PD still has to rely on conventional antibiotic treatment strategies and less so on alternative methods.

Adult↗
PubMed2001

Surface-enhanced raman scattering of p-nitrothiophenol molecular vibrations of its silver salt and the surface complex formed on silver islands and colloids.

The interpretation of the surface-enhanced Raman scattering (SERS) spectra of p-nitrothiophenol (p-NTP) is reported. SERS spectra were obtained by vacuum evaporation and casting of p-NTP onto silver island films, and also from colloidal silver solutions. The vibrational spectra of the silver salt (p-NTP-silver) were obtained for a direct comparison with the SERS of p-NTP chemically adsorbed onto Ag. Chemisorption of p-NTP through S-Ag bonding is indirectly proven by the disappearance of the S-H stretching mode. The Raman scattering spectrum of the silver salt is in good agreement with the SERS spectra of the silver surface complex. The spectral interpretation was aided using density functional theory calculations of the molecular spectra of p-NTP and that of the Ag-p-NTP.

Colloids↗
PubMed1988

Serum concentrations and accumulation of silver in skin during three months treatment with an anti-smoking chewing gum containing silver acetate.

Silver acetate chewing gum was used for 12 weeks as a smoking deterrent in 21 adults. The effect of silver on serum concentrations, its accumulation in the skin and the risk of developing clinically evident argyria were investigated. Serum concentrations of silver clearly rose after chewing gum use had started, and concentrations quickly returned to normal after use had ceased. In most cases the number of silver granules in skin biopsies, observed by autometallography, increased after the gum had been used for 12 weeks. No one developed clinical signs of argyria. Silver acetate containing remedies can be used as an aid to stop smoking, but the consumption must be monitored to avoid accumulation of larger amounts of silver in the body.

Acetates↗
PubMed1989

Silver enhancement of tissue mercury: demonstration of mercury in autometallographic silver grains from rat kidneys.

The autometallographic silver enhancement method has been applied increasingly to detect trace amounts of mercury in preparations of biological tissue. It has, however, been difficult to establish the presence of a core of mercury within the silver grain by direct methods such as energy dispersive X-ray analysis. In the present work, a sample of autometallographic silver grains was prepared from kidneys of rats exposed to mercury in the drinking water. Frozen sections from the kidneys were silver-enhanced and subsequently all organic material was removed by enzymatic digestion. The remaining pellet of silver grains was analyzed by proton-induced X-ray emission (PIXE) and mercury was demonstrated in an amount of 0.1-0.5% compared to silver. In addition, it was demonstrated that two pools of catalytic mercury compounds exist, probably corresponding to sulfide- and selenium-bound mercury.

Animals↗
PubMed1999

Over-the-counter drug products containing colloidal silver ingredients or silver salts. Department of Health and Human Services (HHS), Public Health Service (PHS), Food and Drug Administration (FDA). Final rule.

The Food and Drug Administration (FDA) is issuing a final rule establishing that all over-the-counter (OTC) drug products containing colloidal silver ingredients or silver salts for internal or external use are not generally recognized as safe and effective and are misbranded. FDA is issuing this final rule because many OTC drug products containing colloidal silver ingredients or silver salts are being marketed for numerous serious disease conditions and FDA is not aware of any substantial scientific evidence that supports the use of OTC colloidal silver ingredients or silver salts for these disease conditions.

Colloids↗
PubMed1989

Silver binding to rabbit liver metallothionein. Circular dichroism and emission study of silver-thiolate cluster formation with apometallothionein and the alpha and beta fragments.

We report new spectroscopic properties for a range of silver-metallothionein species. The binding reactions that take place following addition of Ag+ to rabbit liver apoMT 2, and the apo alpha and -beta fragments have been studied using the techniques of circular dichroism (CD) and emission spectroscopy. Titrations carried out at 20 degrees C and 55 degrees C reveal for the first time the formation of a sequence of clusters (Ag6-MT, Ag12-MT and, finally, Ag18-MT) as Ag+ is added to rabbit apoMT 2. (The division of mammalian metallothioneins into two major subforms, MT 1 and MT 2, is based on differences in molecular charge, which results from differences in the sequence of amino acids that do not involve the cysteines.) It is proposed that the novel Ag18-MT complex forms with a structure that involves a well defined three-dimensional structure, in the same manner as that recently reported for the Hg18-MT complex (Cai, W. and Stillman, M. J., (1988) J. Am. Chem. Soc. 110, 7872-7873). Addition of silver in excess of 20 mol equivalents leads to the collapse of this structure. At the elevated temperatures, it is suggested that the protein can exert cooperativity so that completely filled domains are formed rather than mixtures of complexes. This contrasts with the kinetic product in which metals are bound across the peptide chain forming more random "cross-linked" regions in place of the cluster structure. CD spectra were recorded as Ag+ was added to the alpha and beta fragments formed from rabbit liver MT 1. The silver-containing fragments are less stable than the Ag-MT. The alpha and beta fragments exhibit CD spectral patterns indicative of stoichiometrically defined species. The presence of Ag3- alpha MT 1 and Ag6- alpha MT 1 is suggested by the spectral data obtained at 20 and 55 degrees C. Formation of Ag3- beta MT 1 is suggested by the spectral data recorded at 20 degrees C for the beta fragment. We also report that silver-containing metallothioneins are luminescent. Both the position of the band maximum in the 460-600 nm region and the emission intensity are strongly dependent on the stoichiometry of silver to protein. In the range of molar ratios for silver:MT of 1-12, bands at 465 and 520 nm intensify to a maximum for Ag10-MT 2. A band at 575 nm reaches a maximum for Ag16-MT 2. Analysis of the emission data suggests that Ag+ binds in a domain specific mechanism to apoMT 2.

Animals↗
PubMed1997

Efficiency of a silver ring in preventing exit-site infections in adult PD patients: results of the SIPROCE Study. Silver ring Prophylaxis of the Catheter Exit Site.

A randomized, multicenter clinical trial was conducted to evaluate the efficiency in preventing exit-site infection of a silver ring mounted on peritoneal dialysis (PD) catheter and placed at skin level (designed by Grosse-Siestrup, 1992). Eligible patients stratified by diabetes mellitus were monitored prospectively for 12 months using a detailed structured inventory. New patients starting PD treatment during the study period were followed for at least 3 months. Basic characteristics of the silver ring group (N = 86) and controls (N = 88) such as age, sex, S. aureus nasal carriage, type of PD catheter placement and catheter indwelling time, mode of PD, and number of connections for bag exchanges did not differ significantly between the two groups. Nineteen exit-site infections occurred in the silver ring group and 15 in the control group. The incidence of "equivocal" exit-site findings and time of improvement to a "good" or "perfect" exit site were similar in both groups. Kaplan-Meier analysis of the probability of an infection-free time interval revealed no statistically significant difference between subjects with the silver device and controls. In 6 of the 86 cases, displacement of the silver ring caused severe tunnel infection followed by catheter loss in 2. We conclude that the silver ring used in this setting is not effective in preventing exit-site infections in PD patients.

Bacterial Infections↗
PubMed2006

Preparation of novel silver-gold bimetallic nanostructures by seeding with silver nanoplates and application in surface-enhanced Raman scattering.

Novel silver-gold bimetallic nanostructures were prepared by seeding with silver nanoplates in the absence of any surfactants. During the synthesis process, it was found that the frameworks of silver nanoplates were normally kept though the basal plane of silver nanoplates became rugged. The real morphology of these nanostructures depended on the molar ratio of gold ions to the seed particles. When the molar ratio of gold ions to silver atoms increased from 0.5 to 4, porous or branched silver-gold bimetallic nanostructures could be made. The growth mechanism was qualitatively discussed based on template-engaged replacement reactions and seed-mediated deposition reactions. Due to the unusual structures, they exhibited interesting optical properties. Moreover, they were shown to be an active substrate for surface-enhanced Raman scattering measurements.

Journal Article↗
PubMed1999

Impact of moderate silver carp biomass gradient on zooplankton communities in a eutrophic reservoir. Consequences for the use of silver carp in biomanipulation.

We examined the impacts of moderate gradient silver carp biomass (five levels from 0 to 36 g.m-3, i.e. about 0-792 kg.ha-1) on zooplankton communities of the eutrophic Villerest reservoir (France). During our mesocosm experiment changes in zooplankton assemblages were dependent on silver carp biomass. In the fishless and low fish biomass treatments, zooplankton abundance increased through time, owing to a peak in cladoceran density, but decreased (mainly cladocerans) at highest fish biomass. Copepods and rotifers were less affected at the highest fish biomass and dominated zooplankton communities. We highlighted that the presence of high silver carp biomass could lead to changes in phytoplankton assemblage via the impact on herbivorous zooplankton. Since silver carp efficiently graze on particles > 20 microns, the suppression of herbivorous cladocerans could result in an increase in small size algae (< 20 microns) abundance since these species would be released from grazers as well as competitors (large algae grazed by silver carp) and nutrients levels would be enhanced by fish internal loading. Our results showed that the use of low silver carp biomass (< 200 kg.ha-1) would allow us to minimize these negative effects.

Animal Feed↗
PubMedDate not supplied

Randomized clinical study of Hydrofiber dressing with silver or silver sulfadiazine in the management of partial-thickness burns.

This prospective, randomized study compared protocols of care using either AQUACEL Ag Hydrofiber (ConvaTec, a Bristol-Myers Squibb company, Skillman, NJ) dressing with silver (n = 42) or silver sulfadiazine (n = 42) for up to 21 days in the management of partial-thickness burns covering 5% to 40% body surface area (BSA). AQUACEL Ag dressing was associated with less pain and anxiety during dressing changes, less burning and stinging during wear, fewer dressing changes, less nursing time, and fewer procedural medications. Silver sulfadiazine was associated with greater flexibility and ease of movement. Adverse events, including infection, were comparable between treatment groups. The AQUACEL Ag dressing protocol tended to have lower total treatment costs (Dollars 1040 vs. Dollars 1180) and a greater rate of re-epithelialization (73.8% vs 60.0%), resulting in cost-effectiveness per burn healed of Dollars 1,409.06 for AQUACEL Ag dressing and Dollars 1,967.95 for silver sulfadiazine. A protocol of care with AQUACEL(R) Ag provided clinical and economic benefits compared with silver sulfadiazine in patients with partial-thickness burns.

Adult↗
PubMed2003

Mode of bactericidal action of silver zeolite and its comparison with that of silver nitrate.

The properties of the bactericidal action of silver zeolite as affected by inorganic salts and ion chelators were similar to those of silver nitrate. The results suggest that the contact of the bacterial cell with silver zeolite, the consequent transfer of silver ion to the cell, and the generation of reactive oxygen species in the cell are involved in the bactericidal activity of silver zeolite.

Anaerobiosis↗
PubMed1983

Toxic effects of silver-silver chloride electrodes on vascular smooth muscle.

We found that silver, either as silver metal or silver chloride, exerted toxic effects on the smooth muscle of isolated cannulated hamster cheek pouch arterioles. Silver initially stimulated the smooth muscle, producing a marked vasoconstriction. The vessels then dilated back to control diameters. Once the arterioles began to dilate, they became refractory to norepinephrine or potassium stimulation. We caution the use of silver in the presence of smooth muscle, especially when tissue mass is small or free protein concentration is low.

Animals↗
PubMed1983

[Determination of silver and cerium in the liver and the kidney from a severely burned infant treated with silver sulfadiazine and cerium nitrate].

Silver and cerium in the liver and the kidney from severely burned infant were analyzed by neutron activation method. The patient was treated topically with cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for 3 months. Then, the treatment with these drugs was stopped because of abdominal distention. The patient died 1 month after the cessation of the treatment with these drugs. The tissue specimens, blank liver sample and reference standards were irradiated with TRIGA MARK II Reactor of Rikkyo University. About 1 month after the irradiation, the activities were measured with a Ge(Li) detector coupled to a 4096 channel pulse height analyzer. A large amount of silver was detected both in the liver and in the kidney and a trace of cerium only in the liver. A considerable amount of silver was detected in the liver and its quantity was about 1600 times more than that of normal livers reported by Hamilton, Minski and Cleary (1972-73). Neither silver nor cerium were detected in the blank liver. These results suggest that prolonged topical chemotherapy of cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for the extensive burn injuries causes considerable absorption of silver and cerium into the liver and the kidney.

Anti-Infective Agents, Local↗
PubMed1988

Coloration of silver-stained protein bands in polyacrylamide gels is caused by light scattering from silver grains of characteristic sizes.

This study investigates the physical basis of color effects in the detection of proteins in polyacrylamide gels by silver staining. Specifically, the hypothesis that different colors may correlate with the development of silver grains of characteristic sizes was investigated by electron microscopy. Protein bands that stained brown, yellow, and blue were excised from stained gels and prepared for electron microscopy by thin-sectioning. In each case, the size distributions of globular silver grains were determined directly from the electron micrographs. We found that blue bands have larger silver grains (with diameters of 40-100 nm) than yellow (21-39 nm) or brown bands (17-35 nm). On the basis of these and other observations, a general mechanism is proposed whereby chemical specificity of electrophoretically separated proteins is expressed in color-specific silver staining.

Electrophoresis, Polyacrylamide Gel↗
PubMed1995

Absence of symptoms in silver refiners with raised blood silver levels.

Silver has been implicated as a cause of ill health, related largely to its use in the medical setting as a treatment for burns and in prosthetic cements. This report discusses occupational silver exposure in two workers with blood silver levels of 49 micrograms/l and 74 micrograms/l who were asymptomatic and showed no signs of argyric neuropathy which has previously been described at blood silver levels as low as 10 micrograms/l. One of the men showed non-characteristic clinical signs of argyrosis. The clinical findings, results of environmental monitoring and effects of environmental improvements on blood silver levels are discussed.

Adult↗
PubMedDate not supplied

Comparison of silver sulfadiazine 1% with chlorhexidine digluconate 0.2% to silver sulfadiazine 1% alone in the prophylactic topical antibacterial treatment of burns.

Wound bacterial colonization in 118 patients treated with chlorhexidine digluconate 0.2% in silver sulfadiazine 1% applied daily to the burn wounds was compared to that of 135 comparable patients similarly treated with silver sulfadiazine 1%. With chlorhexidine digluconate 0.2% in silver sulfadiazine 1%, colonization by Staphylococcus aureus was less frequent (38%) than with silver sulfadiazine (54%, p = 0.016). No statistical difference was found for colonization by Enterococcus faecalis, Pseudomonas aeruginosa, or Enterobacter cloacae. Washing of the wounds of 65 patients with chlorhexidine gluconate 4% during daily dressing changes was associated with reduced wound colonization by S. aureus (35% versus 51%, p = 0.03) and P. aeruginosa (8% versus 16%, p = 0.08) when compared to the 188 washed with nonantibacterial soap. Chlorhexidine, whether added to the topical agent silver sulfadiazine (chlorhexidine digluconate 0.2%) or in the bath soap (chlorhexidine gluconate 4%), decreased colonization by S. aureus.

Administration, Topical↗
PubMed1998

Lessons to be learned: a case study approach. Finger discoloration due to silver nitrate exposure: review of uses and toxicity of silver in clinical practice.

A 29 year-old lady attended the Accident and Emergency Department of a District General Hospital complaining of increasing black discoloration of the tip of her left middle finger; the appearance resembled that of gangrene. However, it was established that she had been applying silver nitrate to her finger, as prescribed by her general practitioner for the treatment of a small granuloma. Hence, the true diagnosis was of localised tissue necrosis, secondary to application of the silver nitrate sticks. On early discontinuation of the therapy, there was complete recovery. In consequence, it is recommended that the practice of unsupervised local application of silver nitrate to the fingers should be discontinued. Opportunity is taken herein to review the uses of silver nitrate in clinical situations--and of silver in any of its many other forms--together with their respective adverse effects.

Adult↗