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At least 19 recordsLinked to original sources

[Effect of silver compounds on viruses in water].

Two commercial substances, Certisil and Micropur, containing microbicidal silver compounds and destinated for decontamination as well as preservation of water were examined for virus inactivating activity against ECBO-, influenza A, Newcastle Disease, pseudorabies and vaccinia viruses in drinking water. In the recommended concentration as well as higher concentrated the lability of the viruses was increased by the silver compounds. This activity which cannot be designated as a true virucidal effect was clearly evident in the case of ECBO and vaccinia viruses, moderate on influenza and pseudorabies viruses but insignificant on Newcastle disease virus. Two combined silver compounds, Certisil-Combina and Sanosil, each containing an immediate microbicidal part besides silver differed in their antiviral activity. The chlorine separating part of Certisil-Combina didn't cause an improvement or acceleration of the destabilizing effect on viruses compared to the pure silver compound, while the hydrogen peroxide part of Sanosil led to a better and continuing inactivating influence on the viruses which were merely reduced in infectivity by 99,9% within one day. Only in the case of evident or suspected contamination of water reservoirs by viruses the addition of a combined silver drug with oxygen separating part seems to be useful.

Antiviral Agents

Analytical findings in a fatal poisoning with silver compound.

A 69-year-old male radio technician drank an unknown amount of a liquid and died within 5 h at a hospital. Mainly silver, potassium, and calcium, among other substances, were found in the residue of the liquid from the empty bottle by means of the spectrographic method (30.7% silver and 25.5% potassium using atomic absorption spectometry [AAS] method). The toxicological analysis of the postmortem material for silver performed by the flame AAS method (stomach, 2.43 micrograms/g; intestines, 1.12 micrograms/g; liver, 6.29 micrograms/g; kidney, 4.85 micrograms/g; spleen, 30.1 micrograms/g; heart, 10.8 micrograms/g; lung, 14.8 micrograms/g; and brain, 0.61 microgram/g) confirmed fatal silver compound poisoning. The results were verified by the standard additions technique and recovery examination. However, no increase in the potassium concentrations was observed in the postmortem material. There have been no data in available literature on the distribution of silver in tissues in people after oral administration of silver salts.

Aged

Mechanism of prophylaxis by silver compounds against infection of burns.

To clarify tthe mechanism by which local application of silver compounds protects burns against infection, an ion-specific electrode was used to measùre the concentration of silver ions in solutions. By this method it was shown that in burn dressings silver ions were reduced to a very low level by precipitation as silver chloride. The antibacterial effect was found to depend on the availability of silver ions from solution in contact with precipitate. Between 10(-5) and 10(-6) molar silver nitrate solution in water was rapidly bactericidal. The minimal amount of silver nitrate causing inhibition of respiration of skin in tissue culture was about 25 times the minimal concentration of silver nitrate that inhibited growth of Pseudomonas aeruginosa.

Adsorption

[Serum and tissue silver levels after burns treated with silver compounds].

This study was performed in order to investigate serum and tissue silver levels in burns which were used 10 percent silver nitrate as a topical agent. We formed four groups of animals and pulverized 10 percent silver nitrate solution to the first group (GI) that included ten rabbits of which backs were burned by boiling water and silver sulphadiazine cream to second group (GII) with nine rabbits. We carried out 10 percent silver nitrate solution to the first control group (GIII) and silver sulphadiazine cream to the second control group (GIV) each of which had seven animals with unburned skin. We obtained blood samples from every animal before and after application of topical agent on the 1st, 3rd, 7th, 15th, 21st and 28th. We determined serum and tissue silver levels by atomic absorption spectrophotometer in kidney and liver of the animals which were sacrificed on the 28th day. In first and second groups we found that serum silver values reached on 3rd day to the maximum level and then the values decreased gradually. We also determined that diminution of the serum silver levels were prominent following on 15th day. It was shown that there was no silver in the serum on 28th day except four animals. The silver deposition in the liver was much more than in the kidney. Between these two groups there was significant difference neither in the serum on the same days nor the tissue silver levels. According to these data it was concluded that serum and tissue silver levels with 10 percent silver nitrate used in burns produced no difference from that of 1 percent silver sulphadiazine cream.

Administration, Topical

[Effect of silver preparations on the microflora regenerated from a condensate of atmospheric water vapor in a hermetically-sealed chamber].

The effect of different silver compounds (silver sulphate, silver nitrate, electrolytic ionic silver) on microorganisms in water reclaimed from the atmospheric condensate in an enclosed environment was investigated. The following microorganisms were examined: Alcaligenes faecalis, Citrobacter freundii. Aeromonas hydrophila, Staphylococcus epidermidis, etc. The ionic silver concentrations in solution varied from 0.1 to 10 mg/l. The efficiency of the silver compounds was found to depend on the microbial strain, ionic silver concentration in solution, and time of exposure. The microflora of the reclaimed water proved to be highly resistant to the preservatives which was strongly associated with the bacterial physical and chemical composition of the products preserved.

Aeromonas

Partitioning and effects of silver in amended freshwater sediments.

Sediments that represented a wide range of characteristics were amended with silver compounds to observe partitioning and bioavailability. In laboratory studies, silver partitioning to particulates, sediment pore water, and overlying water was measured and bioavailability of silver was determined using Hyalella azteca in 10-day sediment toxicity tests. Three silver compounds were used as sources of silver for this study: silver nitrate, silver chloride, and silver thiosulfate complex. Sediment amendment procedures were adjusted as necessary depending on the characteristics of the individual compounds. Several sediment characteristics such as organic carbon, pH, redox, and acid volatile sulfides regulated silver partitioning and bioavailability. Bioavailability of silver was correlated with the overlying water concentration of silver. Ten-day LC50 values ranged from 1.62 to 379.7 mg Ag/kg for H. azteca exposed to sediments amended with AgNO3. In laboratory experiments, silver chloride and silver thiosulfate were orders of magnitude less toxic and bioavailable than silver nitrate, with 10-day LC50 values greater than the highest concentrations of AgCl and silver thiosulfate complex amended to sediments (2560 and 1125 mg Ag/kg, respectively.

Animals

Systemic argyria.

A 74 year old man presented with signs and symptoms of mild cardiac failure. His face and chest were severely discoloured, which was thought to be due to cyanosis. He deteriorated and died of bronchopneumonia. At post mortem examination multiple organs, including the skin, showed silver pigment deposition; he also had a gastric malignant neuroendocrine tumour. He gave no history of contact with silver compounds. Systemic argyria caused by chronic ingestion of silver compounds is a rare condition which, apart from its cosmetic effects, is thought to be relatively harmless; it is not thought to be carcinogenic. This condition can pose diagnostic problems for both clinicians and pathologists.

Adenoma

In vitro quantitative study of newly made antibacterial braided nylon sutures.

This study was done to examine quantitatively the antibacterial property of a newly made, silver compound coated braided nylon suture and to confirm the previously reported qualitative antibacterial data. Three representative bacterial species were used and they were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The suture specimens were embedded in a custom built plastic device filled with a fixed concentration of bacteria for predetermined periods of incubation. A direct current ranging from 0.4 to 40.0 microamperes was applied to the suture specimens. The bacterial suspension was periodically removed for a standard plate count in order to determine quantitatively the antibacterial capability of the suture specimens. The amounts of silver ions released to the medium under various direct current levels were also determined by a pH/ion meter. The antibacterial property of the suture was evident in the anode site of the material, and at a fixed current, the degree of bacteriostatic effect depended upon the type of bacterial species. For example, a difference of almost 10(3) in the number of Pseudomonas aeruginosa was observed within a period of six hours. The responses of Staphylococcus aureus and Escherichia coli to the silver compound coated nylon thread, however, were not as drastic as Pseudomonas aeruginosa. These quantitative data were consistent with the previously reported qualitative observation of the width of clear zone in bacterial culture plates. The silver ion concentration in the medium increased with increasing either the current level or time, or both. At the end of six hours, the ion concentrations were 7.3 micrograms per milliliter at 0.4 microampere, 44.3 micrograms per milliliter at 4.0 microamperes and 305.7 micrograms per milliliter at 40.0 microampere.

Anti-Bacterial Agents

Chemical nature of the first products (nuclei) of the argyrophil staining.

In agreement with LIESEGANG (1911) but in disagreement with VOIGT (1957), PARTRIDGE (1957) and WINKELMANN and SCHMIT (1959), the first product in the majority of the traditional argyrophil methods is submicroscopic grains (nuclei) of metallic silver forming in the impregnating bath at the effect of reducing groups of the tissue (argyrophil I reaction). It is the localization pattern of the metallic silver nuclei that determines the distribution of the silver in the final microscopic image, and not the colloid character of the tissue, as stated by VOIGT (1952) and others. In special cases, colloid grains of certain silver compounds (non-metallic silver nuclei) forming with the contribution of the tissue (argyrophil II reaction) in the impregnating bath constitute the basis of the staining. There are argyrophil methods which consist of pretreatments and a physical development but have no impregnation phase. In one part of them, non-metallic silver nuclei forming with the contribution of the tissue (argyrophil II reaction) in the physical developer, in the other part, certain points of the tissue structure with favourable chemical composition, capable of catalyzing the interaction of silver ions and the reducing component of the physical developer (argyrophil III reaction) serve for the initiation of the staining.

Animals

[The disinfection of the oral mucosa].

For evaluation of antiseptics intended for use on mucous membranes various effects, as bactericidal and fungicidal but also bacteriostatic and fungistatic effects as well as other mechanisms, have to be considered. The application of antiseptics on the oral mucous membrane is indicated to prevent wound infections, bacteremia following surgical intervention, infection caused by injuries as for example prosthetic ulcers as well as it is indicated for prophylaxis and therapy of infections like colds and for prevention of exogenic dissemination of bacteria. The substances used essentially are PVP-iodine-solutions, cation-active compounds, organic mercury- and silver-compounds and hydrogen peroxide-solutions. It has to be taken into account, however, that the toxicological properties of these substances vary. To this day there exists no generally accepted test model for the evaluation of these mucous membrane antiseptics. Therefore a test-solution on the basis of chlorhexidine digluconate was examined with the help of a rinse- and a swab-method, respectively. The total bacterial counts and the number of alpha-haemolytic streptococci was determined. The rinse-method resulted in reduction factors of log 1.0 after 5 to 120 min and the swab-method--applied at the buccal mucous membranes--in reduction factors of about log 1.5 after 5 min and log 1.0 to 1.2 after 120 min. At the gingival margin of the front teeth reduction factors rose from log 1.55 after 5 min to log 1.85 after 120 min. Possibly this rise was due to an after-effect of the tested antiseptic in this region. For examination of antiseptics a combination of both test methods is recommended.

Bacteria

Silver nylon cloth: in vitro and in vivo evaluation of antimicrobial activity.

The topical agents used in burn care today, although beneficial, do have limitations, the most important of which is the failure to prevent or treat burn wound infections in patients with extensive injuries. Therefore, we evaluated the antimicrobial activity of two silver nylon fabrics (SN and HRS) on the growth of S. aureus, P. aeruginosa, and C. albicans. The theoretical advantages of these nylon fabrics over presently available silver compounds is their ability to continuously release silver ions into the burn wound as long as the material is in contact with the wound. Additionally, the release of silver from these fabrics can be augmented electrolytically. The results of these experiments indicated that both materials were microbicidal in vitro for all three test organisms. Furthermore, the antimicrobial activity could be significantly augmented by passing a weak DC current through the material, which increased the rate of release of silver ions from the fabrics. In vivo, HRS was as effective as silver sulfadiazine in preventing colonization of the burn wound. The use of silver nylon fabrics thus appears to be a promising way of delivering large quantities of silver ions into the burn wound without the potential side effects of a carrier molecule or cream.

Bandages

Light and electron microscopic localization of silver in biological tissue.

A method is described that visualizes trace amounts of silver in frozen, paraffin and epon sections from biological tissue. After exposure to light, which ensures reduction of silver ions that are not bound to sulphide, histological sections from animals treated with silver compounds are exposed to a photographic developer containing silver ions. Tissue silver acts as a catalyst for the hydroquinone reduction of silver ions to metallic silver which then accumulates at the site of the trace deposit. Light and electron micrographs showing silver in different organs from albino rats treated with silver lactate are presented. Localization of silver in motor neurons of the spinal gray matter and pons indicates a transport of silver over the blood-brain barrier. Silver precipitates in fetal liver suggest that silver ions can penetrate the placental barrier.

Animals

Interaction of the human leukocyte proteinases elastase and cathepsin G with gold, silver and copper compounds.

Gold thiomalate and the corresponding silver and copper derivatives were investigated as inhibitors of the human leukocyte proteinases elastase and cathepsin G. The kinetic inhibition mechanism for gold- and silver thiomalate is of the hyperbolic non-competitive type with both enzymes and the inhibitory efficiency of the metals increases in the order Cu less than Ag less than Au. On the contrary, D-penicillamine derivatives of the three metals do not influence at all the activity of the two proteinases. Although gold thiomalate is the most efficient of the investigated metal compounds (Ki = 33 microM and 25 microM for elastase and cathepsin G, respectively), the hyperbolic nature of the inhibition imposes a serious limit to its practical usefulness since the maximum inhibitory action on both enzymes is about 40%. We suggest that, in order to act as inhibitor, a copper, silver or gold compound must be able to easily transfer the metal to the enzyme.

Cathepsin G