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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

[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

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

[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

[Amperometric titration of erythrocyte membrane sulfhydryl groups].

The best conditions are selected for amperometric titration of erythrocyte membranes SH-groups by means of silver ions. On the basis of the experimental data, two types of SH-groups according to their capacity of binding Ag+ are found in the membranes. Dynamics of transition of SH-groups of types I into SH-groups of type II is studied. The chemical model explaining the presence of two bends in the course of the membranes amperometric titration curve is created. Calculations were made for the products of R-S-Ag solubility for SH-groups of type I and SH-groups of types I and II as well as for entropy and heat of formation of silver compounds with the membranes sulphydryl groups.

Cell Membrane

Tissue deposition of silver following topical use of silver sulphadiazine in extensive burns.

Silver sulphadiazine has been applied to the burn wounds of 509 patients during the past 10 years. Eleven patients with burns covering more than 20 per cent of the body surface showed silver deposits in the mucosa of the lips, gingiva and cheeks. The colour of the burn wound was also slightly darker than in patients not treated with silver compounds. This darker colour spontaneously disappeared during the year following discharge from hospital. The pathogenesis of silver deposition has been discussed in relation to other published studies.

Administration, Topical

Silver impregnation methods for reticulum fibers and reticulin: a re-investigation of their origins and specificity.

Maresch (1905) introduced Bielschowsky's silver impregnation technic for neurofibrils as a stain for reticulum fibers, but emphasized the nonspecificity of such procedures. This lack of specificity has been confirmed repeatedly. Yet, since the 1920's the definition of "reticulin" and studies of its distribution were based solely on silver impregnation technics. The chemical mechanism and specificity of this group of stains is obscure. Application of Gomori's and Wilder's methods to human tissues showed variations of staining patterns with the fixatives and technics employed. Besides reticulum fibers, various other tissue structures, e.g. I bands of striated muscle, fibers in nervous tissues, and model substances, e.g. polysaccharides, egg white, gliadin, were also stained. Deposition of silver compounds on reticulum fibers was limited to an easily removable substance; the remaining collagen component did not bind silver. These histochemical studies indicate that silver impregnation technics for reticulum fibers have no chemical significance and cannot be considered as histochemical technics for "reticulin" or type III collagen.

Connective Tissue Cells

Structures of silver sulfonamides.

The structures of silver sulfonamides were found to depend highly on the substituent at the amide nitrogen of the sulfonamide. Silver is coordinated to that nitrogen and the sulfonamide is in the amido form if no substituent is present or if the substituent is a phenyl, acetyl, or 2-pyrimidyl group. If the substituent is a 2-thiazolyl or 2-pyridinyl group, the sulfonamide is in the imido form and silver coordinates to the nitrogen of the substituent. Depending on the number of suitable donor atoms per sulfonamide, the silver compounds are charged or uncharged and the primary amino group may be involved in complexation.

Chemical Phenomena

Absence of toxic effects in silver reclamation workers.

Recent reports have alleged that silver presents a toxic hazard to exposed workers. To define the potential risks of long-term exposure to silver better, a cross-sectional investigation was conducted of 27 Caucasian males occupationally exposed to primarily insoluble silver compounds and 27 matched referents. Physical examination and electron microscopy of skin biopsies revealed no cases of generalized argyria. Measurements of facial discoloration, judged from color photographs by panels of laymen and physicians, showed no significant difference between the two groups. Although 29% of the silver workers and none of the referents exhibited ocular silver deposition, optometric and contrast sensitivity test results revealed no significant deficits in visual performance. The kidney and respiratory findings were essentially normal in both populations. Despite the increased presence of silver in the blood, feces, and hair of the recovery workers versus the referents, there was no evidence that chronic silver exposure adversely affected the health of these employees.

Air Pollutants, Occupational

Newly made antibacterial braided nylon sutures. I. In vitro qualitative and in vivo preliminary biocompatibility study.

A new type of braided nylon thread with a silver compound coating was made for the purpose of designing a biocidal suture material. The study used standard bacterial culture techniques to evaluate the antibacterial property of the new Ag-coated nylon thread. Seven types of bacterial species were tested; S. aureus, E. coli, P. aeruginosa, K. pneumoniae, S. dysenteriae, S. maruslens, and P. mirabilis. The commercial size 2/0 Nurolon suture from Ethicon served as the control. A weak direct current ranging from 0.4-400 microA was applied to the specimens to examine whether the biocidal property of silver could be enhanced by current. The antibacterial property was evaluated by the width and sterility of the clear zone in the bacterial culture plates. It was found that the new nylon thread exhibited very good to moderate bactericidal property toward these seven bacterial species. P. aeruginosa was the most sensitive species, while P. mirabilis was the least sensitive one. Application of direct current through the Ag-coated specimens positively enhanced their antibacterial property and the degree of enhancement depended on the direct current level. The material also exhibited an antibacterial property toward well-established bacterial colonies, but the effect was less strong than the case when direct current was applied simultaneously with incubation. Silver ions released from the coated nylon thread were responsible for the observed antibacterial property; and the application of a weak direct current to the material enhanced this effect. A preliminary biocompatibility study of this new material in rat gluteal muscle indicated that the new material caused less inflammatory reaction than the control Nurolon suture up to 60 days after implantation.

Animals

Argyrol, argyrosis and the acquisition of art.

Argyrosis is a now unfamiliar ocular condition with the lapsing of Argyrol and other related silver compounds from the ophthalmic dispensary. It gives rise to a characteristic clinical picture in the conjunctiva and cornea. Argyrol was invented by Albert Barnes and, with the fortune he made, he was able to gather one of the greatest collections of modern art. The collection is displayed at the Barnes Foundation in Philadelphia.

Aged

Silver polymethyl methacrylate antibacterial bone cement.

An improved antibacterial bone cement was sought based on the addition of low concentrations of inorganic silver compounds to polymethyl methacrylate. Composites with AgCl, Ag-AgCl, Ag2O, Ag2SO4 and Ag3PO4 in concentrations of 0.05% to 1% by weight, were tested in vitro against bacterial cultures. All were effective, but Ag2SO4 was especially so, even after 7 weeks of incubation in normal saline. Compressive strength of the cement was not affected by these additions, except in the case of Ag2O. Biocompabibility tests in rabbit muscle for up to 12 weeks showed no significant difference between the Ag -PMM and plain PMM in tissue reactivity, both being minimal. These features, coupled with the broad spectrum of antibacterial activity and low allergic potential of silver, make Ag-PMM an attractive alternative to conventional organic antibiotic/bone cement composites.

Acrylic Resins

Techniques for converting Golgi precipitate in CNS neurons into stable electron microscopic markers.

Direct electron microscopy of nervous tissue stained with the Golgi impregnation method is unsatisfactory because the cytoplasm of the cell bodies and processes of the impregnated neurons are completely filled with a compact precipitate of electron dense silver chromate. This precipitate entirely obscures the cytological details of the impregnated neurons. Because of its solidity and instability in aqueous solutions, the silver chromate is also a source of inconvenience during the preparation of the ultrathin sections. This review summarizes methods that have been developed with the aim of replacing the Golgi precipitate in CNS neurons with a more convenient electron dense material--for example, heavy metal salts or metallic particles. Conversion of the precipitate into a stable electron dense marker is done before the material is embedded for electron microscopy. The methods include lead, gold, and bromide substitution, treatment with ammonia, direct chemical reduction into metallic silver, and photoreduction of the silver chromate into silver through irradiation with ultraviolet light.

Aminophenols