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PubMedDate not supplied

A review of the dosimetry of 1% silver sulfadiazine cream in burn wound treatment.

A review of the periodical literature relating to burn topical antibacterial agents as listed in the Cumulated Index Medicus from January 1, 1965, through November 30, 1992, as well as bound volumes and unpublished material reveals that the optimal dose and mode of deployment of 1% silver sulfadiazine cream in burn wound therapy have not been fully defined. Defining these should provide better control of sepsis in burn facilities. The effectiveness of a burn topical antibacterial agent depends in part upon the extent to which it is absorbed. The process of absorption of a burn topical antibacterial agent may be likened to that of an in vitro model in which the absorption of a test solute through an isolated preparation of the stratum corneum is determined in a diffusion cell. Some of the determinants are the concentration of the solute, the volume of the solvent, the duration of contact with the membrane, the binding tendency of the solute to the membrane, the integrity and wetness of the membrane, intrinsic factors of the solute/membrane interaction (distribution and diffusion coefficients), and the adjuvant formulation. Three of these (solvent volume, duration of solute contact, and membrane wetness) are readily adjusted. As a possible preliminary to the more effective clinical use of 1% silver sulfadiazine, a ranging of these three factors and of the silver sulfadiazine concentration, should be carried out in a rat model with septic burns. Though control of burn wound bacteria remains of overriding importance, the absorption of silver through the burn wound treated with silver sulfadiazine, binding to normal tissues, is a source of rising concern and requires further investigation.

Administration, Topical↗

PubMedDate not supplied

Corrosion of stainless steel pipes in a hydrotherapy pool by a silver-copper disinfection system.

The silver-copper disinfection system has been shown to be effective for water purification. It emits silver ions that combine with bacteria, causing their death. While disinfecting the water, these silver ions exhibit adverse effects on the stainless steel pipes in hydrotherapy pools. In an oxidation-reduction reaction the silver ions are converted into solid silver that is deposited on stainless steel, causing a corrosion reaction. The corroded steel has a black deposit that readily adheres to the burned patient's skin.

Burns↗

PubMed2000

Sealing furcation perforations with silver glass ionomer cement: an in vitro evaluation.

Furcation perforations sealed with silver glass ionomer cement (Chelon Silver) were evaluated in vitro compared with amalgam. Access cavities were prepared in 25 extracted human molar teeth. The coronal orifices of the root canals were sealed with amalgam and varnish. Naturally occurring coronal leakage through the intact pulp chamber floor was determined quantitatively for each tooth, using a modified fluid transport model, under pressure of 1.2 Atm. Each tooth was then disconnected from the system, perforated at the furcation, and the perforation sealed with either Chelon Silver (10 teeth) or amalgam (10 teeth); five remaining teeth served as a negative control. After incubation for 24 h at 37 degrees C in 100% humidity, teeth were reconnected to the modified fluid transport system, and coronal leakage under pressure was evaluated at 1, 2, 6, 15, and 24 h. Leakage through each tooth was compared with that of its own intact pulp chamber floor before perforation and the groups compared with each other. No significant difference was found between the mean leakage of the intact pulp chamber floors of the two groups. Chelon Silver had a significantly better sealing ability than amalgam (p < 0.01): leakage rate of 0.007 and 0.017 microliter/min, respectively. It is concluded that Chelon Silver could be an adequate sealer for furcation perforations.

Cermet Cements↗

PubMed2003

The legacy of the silver methods and the new anatomy of the basal forebrain: implications for neuropsychiatry and drug abuse.

The first part of the paper highlights the remarkable legacy of the silver methods, with special emphasis on the travails and opportunities offered by the various Nauta methods and their modifications. When the tracer methods based on axoplasmic flow were introduced in the early 1970s, they were exploited on a backdrop of a basic anatomical framework, which had already been established through the tracing of the major CNS pathways by the aid of the silver methods, especially the widely used Nauta-Gygax methods and their modifications. Some of the silver methods that were developed in the late 1960s for the staining of degenerating boutons (e.g. the Fink-Heimer method and de Olmos cupric silver method) provided the necessary technical improvements that eventually led to a new and more productive way to look at the basal forebrain functional/anatomical organization; if it was not for the silver methods, we would in all likelihood still be promoting the nebulous notion of the substantia innominata rather than the concepts of the ventral striatopallidal system and the extended amygdala. The discovery and elaboration of these two macroanatomical systems symbolize what might deservedly be called the "new anatomy" of the basal forebrain. Following a review of the critical experiments which led to the development of the new anatomy of the basal forebrain, its topography in the human is reviewed in drawings of an abbreviated series of coronal sections. The discovery of the ventral striatopallidal system and its thalamic projection to the mediodorsal thalamus rather than to the ventral anterior-ventral lateral thalamic complex ushered in the idea of parallel cortico-subcortical reentrant circuits, which to a large extent has replaced the limbic system as a theoretical framework for neuropsychiatric disorders. The extended amygdala, which appears as a large ring formation around the internal capsule, is still controversial in some quarters, although it is slowly but surely making its way into the general neuroscience literature, especially in the field of addictive disorders. The ventral striatopallidal system and the extended amygdala are interwoven in a complex fashion with the basal nucleus of Meynert within the basal forebrain. Together, these three systems represent important output channels for so-called "limbic" forebrain regions, especially orbitomedial prefrontal cortex and medial temporal lobe structures, which are increasingly implicated in major neuropsychiatric disorders.

Animals↗

PubMedDate not supplied

Controlling wound bioburden with a novel silver-containing Hydrofiber dressing.

Clinicians now recognize that both aerobic and anaerobic microorganisms have the ability to degrade or damage host tissue at a wound site through the production of a variety of enzymes and toxins. Silver-containing dressings offer one method for controlling this polymicrobial wound bioburden, and research efforts are currently ongoing to determine their efficacy against aerobic, anaerobic, and antibiotic-resistant microorganisms. The current study aimed to determine the antimicrobial activity of a new silver-containing Hydrofiber dressing (AQUACEL Ag) on both aerobic and anaerobic microorganisms, using the zone-of-inhibition method. This method provides a measure of the ability of the dressing to make available a sufficient concentration of silver to have an antimicrobial effect. To some extent this test mimics the clinical use of the dressing and predicts its microbicidal activity at the wound-dressing interface. The results show that the silver-containing dressing makes silver available at a dressing-agar interface at a concentration that is effective against a broad range of aerobic, anaerobic, and antibiotic-resistant microorganisms. In the context of wound healing, the results showing antimicrobial activity against antibiotic-resistant microorganisms are particularly important, as the control and eradication of these organisms is a major concern within the health care profession.

Administration, Topical↗

PubMed2005

Isolation of silver- and antibiotic-resistant Enterobacter cloacae from teeth.

Antibiotic-resistant bacteria pose a serious threat to human health; hence the mechanisms that lead to their selection need to be investigated. One possible mechanism is that the silver and mercury in amalgam dental restorations may select for bacteria that contain heavy metal and antibiotic-resistance determinants, leading to the spread of these resistances, particularly if they are contained on the same mobile genetic element. The incidence of silver-resistant bacteria on teeth is investigated in this work. Two silver-resistant Enterobacter cloacae isolates were isolated from infected teeth containing dental restorations. Both isolates were also resistant to ampicillin, erythromycin, and clindamycin. The silE gene, which is encoded on the silver resistance operon, has been sequenced from both isolates. Results suggest that the silver resistance operon is encoded on plasmid DNA.

Dental Amalgam↗

PubMed2006

Efficacy and functionality of silver-coated textiles in patients with atopic eczema.

BACKGROUND: Microbial skin colonization with Staphylococcus aureus is known to play an important role in atopic eczema (AE). Recently, an antibacterial effect of silver-coated textiles on S. aureus colonization has been demonstrated. OBJECTIVES: To investigate clinical efficacy and functionality of silver-coated textiles in AE, a multicentre, double-blind, placebo-controlled trial was conducted. PATIENTS/METHODS: From November 2001 to August 2002, 68 consecutive outpatients clinically diagnosed with generalized AE were included in the study. Inclusion criteria were the clinical diagnosis of AE with a moderate severity as measured by the scoring of atopic dermatitis (SCORAD) index with at least 20. Patients were instructed to wear either silver-coated (verum, 35 patients + 2 dropouts) or cotton garments (placebo, 22 patients + 9 dropouts) directly on the skin for 2 weeks. Only basic skin care and ongoing therapy with topical steroids or oral antihistamines was permitted. Clinical severity was assessed using the 'SCORAD' before, during and at the end of study. Quality of life (QOL), wearing comfort (WC) and functionality (FU) of study clothes were measured in parallel. Patients documented their subjective and objective symptoms daily. RESULTS: In the verum group, eczema improved significantly after 1 week with further enhancement until the end of study (P = 0.03 and P < 0.001). Silver-coated textiles were comparable to cotton in WC and FU. Pruritus and self-assigned skin condition improved significantly more than with placebo (P < 0.001 and P = 0.003). CONCLUSIONS: In conclusion, silver-coated textiles are able to improve objective and subjective symptoms of AE significantly within 2 weeks, showing a good wearing comfort and functionality comparable to cotton.

Adolescent↗

PubMed2005

Silver-containing alginate fibres and dressings.

Silver is a broad-spectrum antimicrobial agent that is gaining more and more importance in the wound-management industry. By incorporating silver ions into alginate fibres, highly absorbent alginate wound dressings with antimicrobial properties can be made. Laboratory studies have shown that by incorporating fine particles of silver sodium hydrogen zirconium phosphate, the silver-containing alginate fibres can maintain the white physical appearances while providing a sustained release of silver ions when in contact with wound exudates. Test results have proven that these fibres are highly effective against bacteria.

Alginates↗

PubMed2005

The effect of a silver-containing Hydrofiber dressing on superficial wound bed and bacterial balance of chronic wounds.

The treatment of chronic wounds represents a major cost to society and has a profound effect on the participant's quality of life. Chronic wounds may have an increased bacterial burden that can impair healing without all the clinical signs of infection. Silver dressings may provide an alternative topical method to control bacterial burden. The primary aim of this study was to evaluate the clinical improvement in chronic wounds through the effect on wound size, maceration, resolution of surface slough and conversion to healthy granulation during a 4-week application of the silver-containing Hydrofiber dressing. This was a single centre, open-label case series study which included a total of 30 evaluable participants: four with diabetic neuropathic foot ulcers, 13 venous stasis ulcers, four pressure ulcers and nine miscellaneous wounds that did not fit any of the previous categories. All participants had adequate vascular supply, indicating the potential to heal. The wounds were stalled or had the signs and symptoms consistent with critical colonisation. The underlying cause of the ulceration was identified and corrected, or the symptoms and signs were treated. This was followed by the application of silver-containing Hydrofiber dressings for a period of 4 weeks. The majority of wounds treated decreased in size (70%) with decreased exudate, decreased purulence and resolution of surface slough (75%). There was an increased quality and quantity of healthy granulation tissue. Unlike some silver dressings, the Hydrofiber and silver combination dressing was unlikely to cause burning and stinging on application. Peri-wound maceration was present in 54% of participants at baseline, and 85% of these resolved with this dressing. A desloughing action was seen in those patients with pre-existing slough at baseline and its removal will lower the bacterial burden of the wound.

Adolescent↗

PubMed2006

Silver dressings: their role in wound management.

Dressings have a part to play in the management of wounds; whether they are sutured or open, usually chronic wounds of many aetiologies which are healing by secondary intention. They traditionally provide a moist wound environment, but this property has been extended through simple to complex, active dressings which can handle excessive exudate, aid in debridement, and promote disorganised, stalled healing. The control of infection remains a major challenge. Inappropriate antibiotic use risks allergy, toxicity and most importantly resistance, which is much reduced by the use of topical antiseptics (such as povidone iodine and chlorhexidine). The definition of what is an antimicrobial and the recognition of infection has proven difficult. Although silver has been recognised for centuries to inhibit infection its use in wound care is relatively recent. Evidence of the efficacy of the growing number of silver dressings in clinical trials, judged by the criteria of the Cochrane Collaboration, is lacking, but there are good indications for the use of silver dressings, to remove or reduce an increasing bioburden in burns and open wounds healing by secondary intention, or to act as a barrier against cross contamination of resistant organisms such as MRSA. More laboratory, and clinical data in particular, are needed to prove the value of the many silver dressings which are now available. Some confusion persists over the measurement of toxicity and antibacterial activity but all dressings provide an antibacterial action, involving several methods of delivery. Nanocrystalline technology appears to give the highest, sustained release of silver to a wound without clear risk of toxicity.

Anti-Infective Agents, Local↗

PubMed1984

The application of the nucleolar organizer region silver staining (AgNOR) to backscattered electron imaging (BEI).

Until recently scanning electron microscopes were mainly used to observe surfaces. However, it has been proved that a backscattered electron detector can give an image (BEI) of the specimen's internal structure after heavy metal staining. In this paper, we report how we have applied the silver staining for NOR-associated proteins to scanning electron microscopy, studying C3H10T1/2 cells in culture. This technique allows to localize, inside the nucleus, the nucleolar arrangement of AgNOR-associated proteins. In BEI imaging, the silver staining shows several intranucleolar silver spot-like deposits sometimes associated in "doublets" as on metaphasic chromosomes. These silver grains probably represent the fibrillar centre location, thought to be the interphasic counterpart of the NORs. However, these silver spot granules are more numerous during interphase.

Animals↗

PubMed1996

Pulp response in primary teeth with deep residual caries treated with silver fluoride and glass ionomer cement ('atraumatic' technique)

Histological assessment of the dental pulps of 55 carious primary teeth was carried out 3 to 58 months after treatment by the 'atraumatic' technique involving application of 40 per cent silver fluoride to residual caries followed by restoration with glass ionomer cement. Fifty of the 55 teeth examined showed a favourable pulpal response, inducing presence of abundant reparative dentine and a wide odontoblast layer. Histological comparisons were made between these teeth and others not treated with silver fluoride but restored with glass ionomer cement, amalgam or zinc oxide and eugenol. Possible mechanisms of the action of silver fluoride in arresting residual caries are discussed. The question of whether or not treatment of carious dentine with silver fluoride represents a biologically acceptable clinical procedure cannot be answered on the basis of pulpal histology alone. The very high concentration of fluoride in commercial preparations of silver fluoride raises several questions concerning its clinical safety.

Adolescent↗

PubMed1974

Properties of silver sulfadiazine-resistant Enterobacter cloacae.

Two silver sulfadiazine-resistant isolates of Enterobacter cloacae obtained in a burns unit where the drug was in use were studied. These strains were resistant to elevated levels of the drug, and they were cross-resistant to silver benzoate, but not to silver nitrate. Growth of the strains in nutritionally poor defined media sensitized them to the inhibitory action of the drug. Exposure of the bacteria to penicillins rendered them susceptible to silver sulfadiazine. The resistant bacteria harbored episomes for resistance to carbenicillin and kanamycin; however, resistance to silver sulfadiazine could not be transferred by these episomes. Twenty-three strains of E. cloacae isolated in a general hospital were sensitive to much lower levels of the drug (</=50 mug/ml).

Cell Wall↗

PubMed1994

Disinfection of human enteric viruses in water by copper and silver in combination with low levels of chlorine.

The efficacy of copper and silver ions, in combination with low levels of free chlorine (FC), was evaluated for the disinfection of hepatitis A virus (HAV), human rotavirus (HRV), human adenovirus, and poliovirus (PV) in water. HAV and HRV showed little inactivation in all conditions. PV showed more than a 4 log10 titer reduction in the presence of copper and silver combined with 0.5 mg of FC per liter or in the presence of 1 mg of FC per liter alone. Human adenovirus persisted longer than PV with the same treatments, although it persisted significantly less than HRV or HAV. The addition of 700 micrograms of copper and 70 micrograms of silver per liter did not enhance the inactivation rates after the exposure to 0.5 or 0.2 mg of FC per liter, although on some occasions it produced a level of inactivation similar to that induced by a higher dose of FC alone. Virus aggregates were observed in the presence of copper and silver ions, although not in the presence of FC alone. Our data indicate that the use of copper and silver ions in water systems may not provide a reliable alternative to high levels of FC for the disinfection of viral pathogens. Gene probe-based procedures were not adequate to monitor the presence of infectious HAV after disinfection. PV does not appear to be an adequate model viral strain to be used in disinfection studies. Bacteroides fragilis bacteriophages were consistently more resistant to disinfection than PV, suggesting that they would be more suitable indicators, although they survived significantly less than HAV or HRV.

Adenoviruses, Human↗

PubMed1998

Tunneled hemodialysis catheters: use of a silver-coated catheter for prevention of infection--a randomized study.

PURPOSE: To determine whether silver-coated tunneled hemodialysis catheters reduce infection and to determine the frequency of central venous thrombosis and stenosis with percutaneous placement of right internal jugular vein dialysis catheters by interventional radiologists. MATERIALS AND METHODS: Ninety-one patients were randomly assigned to a treatment (silver-coated catheter; n = 47) or control (identical catheter without silver coating; n = 44) arm. Baseline venography was performed. Catheter tips were cultured and venography was repeated at catheter removal. RESULTS: Mean duration of catheter placement was 92 days. Infection occurred in 11 patients (five in the treatment group, six in the control group). Tip cultures in 15 patients (eight treatment, seven control) were positive without clinical infection. Infection and colonization rates were slightly but not significantly higher in the treatment group than in the control group. Silver-coated catheters in two (4%) patients were removed due to reaction to the coating. Completion venograms (n = 72) showed new minor abnormalities in four (6%) patients and major abnormalities (stenosis, thrombosis) in three (4%) patients. Permanent venous abnormalities occurred in two (3%) patients. CONCLUSION: Silver coating does not confer a benefit against clinical infection or colonization. Interventional radiologic placement of tunneled dialysis catheters yields a low frequency of permanent central venous thrombosis and stenosis.

Bacteria↗

PubMed2006

Silver-coated textiles in the therapy of atopic eczema.

Atopic skin is mainly determined by a disrupted skin barrier, resulting in a higher susceptibility to external irritants in affected and nonaffected skin. Apart from many other irritant and allergic influences, skin colonization with Staphylococcus aureus is one of the major factors triggering and maintaining atopic eczema (AE). Adequate textile protection with low irritant potential can be helpful in reducing the exposure to exogenous trigger factors. Until now, cotton fabrics have been the state of the art of recommended textiles for patients with AE. The combination of antimicrobial therapy with compatible textiles in terms of biofunctionality is a promising innovative approach. The antibacterial effect of silver-coated textiles on S. aureus colonization has been demonstrated in an open side-to-side comparison. Silver-coated textiles were able to reduce S. aureus density significantly after 2 days of wearing, lasting until the end of treatment (day 7) and even 1 week after removal of the textiles. In addition, there was a significant difference in S. aureus density comparing silver-coated with cotton textiles. In addition, the clinical efficacy and functionality of silver-coated textiles in generalized AE have been examined in a multicenter, double-blind, placebo-controlled trial. They were able to improve objective and subjective symptoms of AE significantly within 2 weeks, showing a good wearing comfort and functionality comparable to cotton without measurable side effects. These therapeutic effects led to a significantly lower impairment of quality of life, already after 2 weeks. Therefore, beside a potent antibacterial activity in vivo, silver-coated textiles demonstrate a high efficacy in reducing the clinical severity of AE showing a wearing comfort comparable to cotton.

Anti-Infective Agents↗

PubMed1977

Identification of nucleolus organizer regions (NORs) in normal and neoplastic human cells by the silver-staining technique.

Silver nitrate has been used to demonstrate the chromosomal location of ribosomal cistrons in nine tissue-culture lines derived from human tumors of various pathological origins. Control individuals have a particular modal number (range 7--10) of D- and G-group chromosomes stained with silver. In the controls, 96.2% of the D- and G-group chromosomes that have a stalk show silver staining, while no relationship can be seen in acrocentric chromosomes without stalks. The tumor cells, whose modal chromosome numbers range from 42 to 68, possess variable numbers of acrocentrics (11--18). The number of chromosomes stained with silver, however, remained at control levels (range, 6--9). These data indicate that, in humans, silver staining may not identify all NORs that contain structural ribosomal genes.

Cell Line↗

PubMed1981

Silver-staining patterns of mammalian epididymal spermatozoa.

Epididymal spermatozoa from 12 species of mammals were stained using silver nitrate and examined with the light microscope. Silver nitrate differentiates many of the gross morphological features of spermatozoa, including the acrosome, subacrosomal region, perforatorium, postacrosomal sheath, neck, dense outer fibers of the core of the midpiece, annulus, principal piece, and end piece. Silver-staining patterns of spermatozoa reveal both species-specific and strain-specific differences, particularly of the sperm head. The biochemical basis of silver staining may be due in part to the presence of sulfhydryl- and disulfide-rich proteins; however, it cannot be explained entirely by the presence of these moieties. The detail obtained using silver nitrate staining, coupled with the ease and rapidity of the procedure, should be useful to workers in many areas of biological and medical research.

Acrosome↗