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Clinical performance of a new silver dressing, Contreet Foam, for chronic exuding venous leg ulcers.

OBJECTIVE: This study aimed to evaluate the safety and performance of a new sustained silver-releasing dressing, Contreet Foam (Coloplast A/S), in the treatment of moderately to highly exuding chronic venous leg ulcers in which healing is delayed due to the presence of bacteria. METHOD: The clinical performance of Contreet Foam was studied for four weeks in 25 patients with moderately to highly exuding delayed-healing venous leg ulcers. Healing was assessed on a weekly basis with reference to the wound-bed tissue composition, degree of odour and pain, dressing performance and the dressing's effect on the peri-ulcer area. Blood samples were analysed for silver content. RESULTS: Twenty-three out of 25 patients completed the study. One ulcer healed and no wound infections occurred during the study period. A mean 56% reduction in ulcer area (from 15.6 to 6.9 cm2) was recorded during the four weeks, and there was a mean 25% reduction in granulation tissue from dull to healthy after one week. Wound odour reduced significantly after one week. Mean dressing wear time was 3.1 days, and there were only minimal incidences of leakage. Serum silver levels did not exceed reference values. CONCLUSION: Contreet Foam was found to be safe and performed well when used in the treatment of delayed-healing chronic venous leg ulcers, combining effective antibacterial properties with excellent exudate management. DECLARATION OF INTEREST: This study was supported by Coloplast A/S, Humlebaek, Denmark.

Aged↗

Effects of an activated charcoal silver dressing on chronic wounds with no clinical signs of infection.

OBJECTIVE: This exploratory, clinical study aimed to explore the effect of an activated charcoal silver dressing (intervention) with cleansing and debridement (control) in reducing the level of bacteria in chronic wounds with no clinical signs of local infection. METHOD: Patients were randomly assigned to the intervention or control group and monitored for two weeks. Samples for bacterial status and cultivation were obtained by surface smear (spatula) and percutaneous aspiration first at baseline and then after 15 days of treatment. Sixty-seven lesions were included in the intervention group and 58 in the control group. RESULTS: At baseline, in the intervention group 71.6% of the wounds were contaminated, 7.5% had a high level of bacteria and 20.9% were infected. In the control group at baseline 65.5% of the wounds were contaminated, 6.9% colonised, 6.9% had a high level of bacteria and 20.7% were infected. There were no colonised wounds in the intervention group. After two weeks, combining totals of contaminated, colonised, a high level of bacteria and infection for each group, 85.1% (57/67) of the wounds in the intervention group had a positive bacterial level management (that is, a reduction in the number of bacteria in the wound) compared with 62.1% (36/58) in the control group (p=0.003). CONCLUSION: Activated charcoal dressings that contain silver control infection and reduce healing times, eliminating bacterial barriers.

Bacterial Infections↗

Colloidal silver as an antimicrobial agent: fact or fiction?

OBJECTIVE: Colloidal silver preparations are marketed on the internet as omnipotent antimicrobial agents, but scientific support for these claims is lacking. This study reports the results of in vitro tests of colloidal silver's antimicrobial activity against several pathogenic or non-pathogenic microorganisms. METHOD: Three samples of colloidal silver were tested: one available commercially on the internet (silver concentration of 22 ppm) and two samples (concentrations of 403 and 413 ppm) which were prepared in our laboratory using standard chemical methods. RESULTS: In an agar-well diffusion assay none of the three colloidal silver solutions had any effect on the growth of the test organisms. All tested bacterial strains were sensitive to ciprofloxacin. Colloidal silver 22 ppm showed no bactericidal activity in phenol coefficient tests. CONCLUSION: As the tested colloidal silver solutions did not show any antimicrobial effect in vitro on the microorganisms, claims of colloidal silver's antimicrobial potency are misleading and there is no place for it as an antiseptic.

Anti-Infective Agents↗

Effect of a new silver dressing on chronic venous leg ulcers with signs of critical colonisation.

OBJECTIVE: To investigate the clinical performance and safety of a new silver-containing wound-contact layer, Physiotulle -Ag (Coloplast), in the treatment of chronic venous leg ulcers with delayed healing and signs of critical colonisation. METHOD: This was an open prospective non-comparative multicentre clinical study. Patients were treated for four weeks with Physiotulle -Ag, which was covered by Alione Hydrocapillary Dressing (Coloplast). RESULTS: Thirty patients were recruited into the study. One ulcer healed after three weeks of treatment. The mean relative ulcer area reduced by 55% after four weeks. Over the study period the mean amount of healthy granulation tissue increased from 26% to 62%, and the mean amount of fibrin decreased from 63% to 32%. The ratio of malodorous wounds was 50% at inclusion, 20% after one week and 3% after four weeks. The dressing was considered easy or very easy to apply in 100% and easy to remove in 89% of dressing evaluations. The dressing combination showed good exudate-management properties. Incidence and severity of maceration, erythema and eczema decreased during the study and no device-related adverse events were recorded. CONCLUSION: Physiotulle -Ag is safe and easy to use in chronic venous leg ulcers in which healing is delayed and with signs of critical colonisation.

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Effect of a sustained silver-releasing dressing on ulcers with delayed healing: the CONTOP study.

OBJECTIVE: To compare the effect of the sustained silver-releasing foam dressing Contreet Foam (ColoplastA/S) with local best practice (LBP) on delayed healing ulcers using a real-life setting. METHOD: A total of 619 patients with ulcers of varying aetiologies were treated for four weeks with either the silver foam dressing or LBP. RESULTS: Wound area was reduced by 50% with the silver foam and 34% with LBP Less slough and maceration, a faster reduction in exudate level and more positive wound progress was achieved with the silver foam. In addition, exudate handling, ease of use, odour and pain improved. Less time was spent on dressing changes, and mean wear time was longer for the silver foam (3.1 days) than for LBP (2.1 days). All differences were statistically significant (p < 0.05). The silver foam dressing outperformed all of the other dressing categories including moist wound healing products and other silver dressings. CONCLUSION: This large-scale comparative real-life study shows that the silver foam dressing supports faster healing of delayed healing wounds.

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Quantitative analysis of methyl parathion pesticides in a polydimethylsiloxane microfluidic channel using confocal surface-enhanced Raman spectroscopy.

A fast and ultra-sensitive trace analysis of methyl parathion pesticides in a polydimethylsiloxane (PDMS) microfluidic channel was investigated using confocal surface-enhanced Raman spectroscopy (SERS). A three-dimensional PDMS-based passive micromixer was fabricated for this purpose. This PDMS micromixer showed a high mixing efficiency because a strong chaotic advection was developed by the simultaneous vertical and transverse dispersion of the confluent streams. The confocal SERS signal was measured after methyl parathion pesticides were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower alligator-teeth-shaped PDMS channel. A quantitative analysis of the methyl parathion pesticides was performed based on the measured peak height at 1246 cm-1. Our method has a detection limit of 0.1 ppm. This value satisfies the requirement recommended by the Collaborative International Pesticides Analytical Council (CIPAC) for the determination of methyl parathion in pesticide formulations. This study demonstrates the feasibility of using confocal SERS for the highly sensitive detection of methyl parathion pesticides in a PDMS microfluidic channel.

Calibration↗

[Measurement and analysis of monophasic action potentials using fractally coated electrodes--I].

The monophasic action potential (MAP) contains a wealth of information about the stat of the myocardium, which makes it very useful for numerous diagnostic and therapeutic applications in patients with heart disease. The silver-silver chloride electrodes which are currently used for the measurement of MAP have poor long-term stability in contact with biological tissue. This study was therefore undertaken with the aim of investigating the electrochemical behaviour of fractally coated leads in terms of their signal-detection performance. Experience gained with these leads in cardiac pacemakers has already demonstrated the long-term stability and biocompatibility of the fractally coated leads. Present results show that, due to their large electrochemically active surface area, fractally coated leads have a very low impedance over a wide frequency range. The negligible polarization artifact of these leads permits the measurement of cardiac potentials immediately after a stimulus. Fractally coated leads are thus highly suitable for the measurement of MAP, and have clear advantages over Ag/AgCl electrodes. The second part of this study reports on the results of MAP measurements using fractally coated leads.

Electrocardiography↗

[Measurement and analysis of monophasic action potentials using fractally coated electrodes--II].

The monophasic action potential (MAP) represents a summed signal formed by overlapping action potentials of myocardial cells close to the tip of the lead. Analysis of the MAP therefore provides detailed information about the electrophysiological effects of autonomous nervous and pharmacological influences on the myocardium, for example adrenergic or cholinergic stimulation of the heart. All known MAP recordings were obtained with Ag/AgCl electrodes, which, thanks to their low polarization properties, ensure reliable MAP measurement. Owing to their toxicity and inadequate long-term stability, however, Ag/AgCl electrodes cannot be implanted. With the aim of making MAP measurement available for implantable devices, fractally coated leads were therefore developed. The aim of the present study was to evaluate the in vivo measurement of fractally coated leads which are characterized by negligible polarization, low impedance over a wide frequency range, high biocompatibility and good long-term stability. In addition, as a result of their extremely high Helmholtz capacities (up to 50 mF/cm2), fractally coated leads permit stimulation and virtually undisturbed recording of MAP with the same pair of electrodes. For the evaluation of MAP measurements with fractally coated leads, a quadrupolar catheter enabling simultaneous MAP recordings with 2 Ag/AgCl electrodes and 2 fractally coated leads was devised. The stimulation pulses were always applied via the fractally coated leads. With both types of electrode, with spontaneous excitation and stimulation, the well-known MAP morphology, with amplitudes of between 10 and 25 mV in the ventricle, and between 5 and 10 mV in the atrium, was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Atropine↗

Needle-type ultra micro silver/silver chloride reference electrode for use in micro-electrochemistry.

A needle-type ultra micro silver/silver chloride reference electrode having a micro capillary with outer and inner diameters of 1.0 microm and 0.5 +/- 0.2 microm, respectively, was constructed. This micro reference electrode can be stuck into a living cell, and is applicable to use in very small environments, such as an electrochemical cell of an electrochemical scanning tunneling microscope or the detection portion of a micro-TAS. Excellent stability and repeatability of the micro reference electrode potential could be obtained by filling the micro capillary with agar gel containing 3.33 mol/L potassium chloride as a salt bridge, by covering the bare part of the silver wire on which silver chloride was deposited, and by electromagnetic shielding of the measurement cell and wire lead from the electromagnetic waves. The electrode showed stable potential for 7 days after its fabrication using 3.3 mol/L potassium chloride aqueous solution containing silver chloride as an internal electrolyte solution. The electrode exhibited constant electrode potential and excellent stability in test solutions of pH 5-9. The electrode potential of a commercial pH glass electrode measured against the micro reference electrode in standard pH buffer solutions was in good accordance with the Nernst equation.

Electrochemistry↗

Influence of AgCl precipitates on the precipitation titration of sodium chloride by constant-current coulometry.

The precipitation titration of sodium chloride with electrogenerated silver ion was studied. The production of a precipitate of silver chloride had a significant effect on the titration results because the precipitate involved unreacted chloride or unreacted silver ion. The accuracy of the method was investigated by changing the introduction time of a sodium chloride solution to the coulometric cell during the process of electrolysis, and examining the dependency on the sample size. The accuracy of the measurement of the precipitation titration is discussed.

Automation↗

Analysis of ethanol and methanol in human body fluids by headspace solid phase microextraction coupled with capillary gas chromatography.

A new method for extraction and analysis of ethanol and methanol in human whole blood, urine and saliva samples based on headspace solid phase microextraction (SPME) using silver sulfide (Ag(2)S) and polyvinyl chloride (PVC) coated on silver wire is described. Unlike commercial fibers, which are coated on fused silica, the proposed fiber has a metallic base to which the coating adheres very strongly. Due to metallic base, this fiber is very durable and is thermally stable up to 250 degrees C. After optimization of coating composition and microextraction conditions, the fiber was used for sampling of methanol and ethanol from human body fluids prior to capillary gas chromatographic analysis. The high recovery (>94%), low detection limits (5.6 mg/L for ethanol and 12.8 mg/L for methanol) and excellent linearity (>0.9900) of calibration graphs made the proposed method suitable for this purpose.

Body Fluids↗

Determination of trace levels of diosmin in a pharmaceutical preparation by adsorptive stripping voltammetry at a glassy carbon electrode.

A systematic study on the electrochemical behavior of diosmin in Britton-Robinson buffer (pH 2.0-10.0) at a glassy carbon electrode (GCE) was made. The oxidation process of the drug was found to be quasi-reversible with an adsorption-controlled step. The adsorption stripping response was evaluated with respect to various experimental conditions, such as the pH of the supporting electrolyte, the accumulation potential and the accumulation time. The observed anodic peak current at +0.73 V vs. Ag/AgCl reference electrode increased linearly over two orders of magnitude from 5.0x10(-8) M to 9.0x10(-6) M. A limit of detection down to 3.5x10(-8) M of diosmin at the GCE was achieved with a mean recovery of 97+/-2.1%. Based on the electrochemical data, an open-circuit accumulation step in a stirred sample solution of BR at pH 3.0 was developed. The proposed method was successfully applied to the determination of the drug in pharmaceutical formulations. The results compared favorably with the data obtained via spectrophotometric and HPLC methods.

Adsorption↗