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Disinfectants
Selected AbstractsChlorhexidine anaphylaxis: case report and review of the literatureCONTACT DERMATITIS, Issue 3 2004A. B. Krautheim Chlorhexidine is a widely used antiseptic and disinfectant. Compared to its ubiquitous use in medical and non-medical environments, the sensitization rate seems to be low. Multivarious hypersensitivity reactions to the agent have been reported, including delayed hypersensitivity reactions such as contact dermatitis, fixed drug eruptions and photosensitivity reactions. An increasing number of immediate-type allergies such as contact urticaria, occupational asthma and anaphylactic shock have been reported. In the case report, we describe anaphylaxis due to topical skin application of chlorhexidine, confirmed by skin testing and sulfidoleukotriene stimulation test (CAST®: cellular antigen stimulation test). The potential risk of anaphylactic reactions due to the application of chlorhexidine is well known, especially that application to mucous membranes can cause anaphylactic reactions and was therefore discouraged. The use of chlorhexidine at a 0.05% concentration on wounds and intact skin was so far thought to be safe. Besides our patient, only one other case of severe anaphylactic reaction due to application of chlorhexidine on skin has been reported. Hypersensitivity to chlorhexidine is rare, but its potential to cause anaphylactic shock is probably underestimated. This review should remind all clinicians of an important potential risk of this widely used antiseptic. [source] Persistent inhibition of human natural killer cell function by ziram and pentachlorophenolENVIRONMENTAL TOXICOLOGY, Issue 4 2005Thyneice R. Taylor Abstract Ziram is a currently used agricultural fungicide. It is also used as an additive in the production of latex gloves. Because of these uses, there is a potential for human exposure to this compound. Pentachlorophenol (PCP) has been used as an insecticide, fungicide, disinfectant, and ingredient in antifouling paints. Currently, it is used as a wood preservative for power-line poles and fence posts. Measurable levels of PCP have been detected in human blood and urine. In previous studies we demonstrated that both these compounds could cause very significant inhibition of the tumor-killing function of human natural killer (NK) cells. NK lymphocytes play a central role in immune defense against viral infection and the formation of primary tumors. So interference with their function could increase the risk of tumor development. In the present study we examined the effects of exposure to ziram or PCP of brief duration (1 h) on the ability of NK cells to destroy tumor cells. NK cells were exposed to either ziram (5,0.5 ,M) or PCP (10,5 ,M) for 1 h followed by 0 h, 24 h, 48 h, or 6 days in compound-free media and then were tested for the ability to lyse as well as to bind tumor cells. A 1-h exposure to as little as 2.5 ,M ziram decreased the ability of NK cells to lyse target tumor cells, which persisted up to 6 days following exposure. The loss of lytic function for from 24 h to 6 days following exposure was accompanied by a comparable loss of NK capacity to bind tumor cells. Exposure to 10 ,M PCP for 1 h caused a progressive loss (greater than 80%) of lytic function within 6 days of exposure. In contrast to ziram, PCP exposure caused no accompanying loss of binding function. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 418,424, 2005. [source] Mutagenicity and disinfection by-products in surface drinking water disinfected with peracetic acidENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2002Silvano Monarca Abstract The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to those found with sodium hypochlorite (NaClO) and chlorine dioxide (ClO2). The Ames test, root anaphase aberration assay, and root/micronuclei assay in Allium cepa and Tradescantia/micronuclei test were used to evaluate the mutagenicity of disinfected samples. Microbiological tests were also performed, and disinfection by-products (DBPs) were identified using gas chromatography/mass spectrometry (GC/MS). A slight bacterial mutagenicity was found in raw lake and river water, and similar activity was detected in disinfected samples. A plant test revealed genotoxicity in raw river water, and microbiological analysis showed that PAA has bactericidal activity but lower than that of the other disinfectants. The DBPs produced by PAA were mainly carboxylic acids, which are not recognized as mutagenic, whereas the waters treated with the other disinfectants showed the presence of mutagenic/carcinogenic halogenated DBPs. However, additional experiments should be performed with higher concentrations of PAA and using water with higher organic carbon content to better evaluate this disinfectant. [source] The effect of cleaning procedures on fracture properties and corrosion of NiTi filesINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2003P. Y. Z. O'Hoy Abstract Aim, To evaluate the effect of repeated cleaning procedures on fracture properties and corrosion of nickel-titanium (NiTi) files. Methodology, New NiTi instruments were subjected to 2, 5 and 10 cleaning cycles with the use of either diluted bleach (1% NaOCl) or Milton's solution (1% NaOCl plus 19% NaCl) as disinfectant. Each cleaning cycle consisted of scrubbing, rinsing and immersing in NaOCl for 10 min followed by 5 min of ultrasonication. Files were then tested for torsional failure and flexural fatigue, and observed for evidence of corrosion using scanning electron microscope (SEM). Four brands of NiTi files were immersed in either Milton's solution or diluted bleach overnight and evaluated for corrosion. Results, Up to 10 cleaning cycles did not significantly reduce the torque at fracture or number of revolutions to flexural fatigue (P > 0.05, two-way anova), although decreasing values were noted with increasing number of cleaning cycles using Milton's solution. No corrosion was detected on the surface of these files. Files immersed in 1% NaOCl overnight displayed a variety of corrosion patterns. The extent of corrosion was variable amongst different brands of files and amongst files in each brand. Overall, Milton's solution was much more corrosive than diluted bleach. Corrosion of file handles was often extreme. Conclusions, Files can be cleaned up to 10 times without affecting fracture susceptibility or corrosion, but should not be immersed in NaOCl overnight. Milton's solution is much more corrosive than bleach with the same NaOCl concentration. [source] Self-sterilizing catheters with titanium dioxide photocatalyst thin films for clean intermittent catheterization: Basis and study of clinical useINTERNATIONAL JOURNAL OF UROLOGY, Issue 5 2007Yuki Sekiguchi Objective: Clean intermittent catheterization (CIC) requires a large number of disposable catheters or a large amount of water and disinfectant. We made titanium dioxide (TiO2)-coated catheters for CIC using technology we have developed previously, and examined the photocatalytic antibacterial effect of this catheter using only light energy and the safety of this type of catheter for practical clinical use. Methods: TiO2 -coated catheters were filled with bacterial cell suspensions and illuminated with a 15-W black-light lamp for testing antibacterial potency. Next, we soaked control toxic materials (zinc diethyldithiocarbamate) and the tips of TiO2 -coated catheters in M05 medium, and evaluated cell toxicity from the numbers of V79 colonies in these dilutions. Then, bodyweight curves and histological tissue changes were observed over a period of time in mouse-transplanted TiO2 -coated catheters and control catheters. Finally, we investigated the use of these TiO2 -coated catheters in 18 patients by questionnaire and bacterial culture of TiO2 -coated catheters and control catheters. Results: The survival rate of Escherichia coli in the liquid inside the TiO2 catheter decreased to a negligible level within 60 min under ultraviolet (UV)-A illumination. The survival rate of Staphylococcus aureus, Pseudomonas aeruginosa and Serratia marcescens also decreased to a negligible level within 60 min. V79 cells showed no cytotoxicity of this catheter, and there was no difference in bodyweight or foreign body reaction between mouse-transplanted TiO2 -coated catheters and control catheters. In a preliminary clinical analysis of 18 patients who voluntarily used this catheter, the rate of positive bacterial culture of the tips of TiO2 -coated catheters was 20% versus 60% for conventional catheters after 4 weeks of use. Conclusion: TiO2 -coated silicone catheters were easily sterilized under certain light sources and were shown to be safe in an experiment using cultured cells and in animal experiments. Sterilizing catheters with TiO2 photocatalyst thin films are expected to be used clinically for clean intermittent catheterization after proper modification based on this study. [source] Surrounded by mycobacteria: nontuberculous mycobacteria in the human environmentJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2009J.O. Falkinham Summary A majority of the Mycobacterium species, called the nontuberculous mycobacteria (NTM), are natural inhabitants of natural waters, engineered water systems, and soils. As a consequence of their ubiquitous distribution, humans are surrounded by these opportunistic pathogens. A cardinal feature of mycobacterial cells is the presence of a hydrophobic, lipid-rich outer membrane. The hydrophobicity of NTM is a major determinant of aerosolization, surface adherence, biofilm-formation, and disinfectant- and antibiotic resistance. The NTM are oligotrophs, able to grow at low carbon levels [>50 ,g assimilable organic carbon (AOC) l,1], making them effective competitors in low nutrient, and disinfected environments (drinking water). Biofilm formation and oligotrophy lead to survival, persistence, and growth in drinking water distribution systems. In addition to their role as human and animal pathogens, the widespread distribution of NTM in the environment, coupled with their ability to degrade and metabolize a variety of complex hydrocarbons including pollutants, suggests that NTM may be agents of nutrient cycling. [source] Use of the modified Robbins device to study the in vitro biofilm removal efficacy of NitrAdineÔ, a novel disinfecting formula for the maintenance of oral medical devicesJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2008T. Coenye Abstract Aims:, To evaluate the use of the modified Robbins device (MRD) to test disinfection strategies against biofilms that form on oral medical devices and to test the biofilm removal efficacy of NitrAdineTM, a disinfectant for the maintenance of oral medical devices. Methods and Results:, Biofilms were grown on discs using the MRD and biofilms formed in this system were used to evaluate the efficacy of NitrAdineTM and to determine the optimal disinfection conditions. Our data indicate that the use of the MRD allows for the rapid and reproducible formation of high-density biofilms. Determination of the efficacy of NitrAdineTM revealed high activity against biofilms tested (e.g. >3 log reduction for Candida albicans and Staphylococcus aureus) and allowed the determination of the optimal conditions for its use. Conclusion:, The high reproducibility and flexibility of the MRD make it an excellent candidate for standardized testing of disinfectants aimed at reducing biofilms on oral medical devices. Using this system, we were able to demonstrate that NitrAdineTM exhibits high activity against biofilms formed by the micro-organisms tested. Significance and Impact of the Study:, Our data suggest that our procedure is appropriate for standardized testing of disinfectants aimed at reducing biofilms on oral medical devices. [source] Peracetic acid as an alternative wastewater disinfectant to chlorine dioxideJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2002S. Stampi Aims: The aim of this study was to compare the efficiency of peracetic acid with that of chlorine dioxide in the disinfection of wastewater from a sewage treatment plant (serving about 650 000 inhabitants) that has been using peracetic acid as a disinfectant since 1998. Methods and Results: A total of 23 samplings were made, each consisting of three samples: from secondary effluent, effluent disinfected with 2 mg l,1 of peracetic acid and effluent disinfected with 2·2 mg l,1 of chlorine dioxide (contact time 20 min). For each sample, measurements were made of the heterotrophic plate count at 36°C, total and faecal coliforms, Escherichia coli, enterococci, pH, suspended solids and chemical oxygen demand (COD). During the first phase of the experiment the peracetic acid was seen to be less efficient than chlorine dioxide. To improve the disinfectant action a system of mechanical agitation was added which led to a greater efficiency in the inactivation of bacteria of faecal origin. Conclusions: Both products were found to be influenced by the level of microbial contamination, the amount of suspended solids and COD but not by the pH of the effluent before disinfection. The immediate mixing of the wastewater and disinfectant caused a greater reduction in enterococci. Significance and Impact of the Study: Since peracetic acid was seen to produce a high abatement of micro-organisms, it can be considered as a valid alternative to chlorine dioxide in the disinfection of wastewaters. [source] Antibacterial activities of essential oils and extracts of Turkish Achillea, Satureja and Thymus species against plant pathogenic bacteriaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2010Recep Kotan Abstract BACKGROUND: The aims of this study were to examine the chemical composition of the essential oils and hexane extracts of the aerial parts of Satureja spicigera (C. Koch) Boiss., Thymus fallax Fisch. & CA Mey, Achillea biebersteinii Afan, and Achillea millefolium L. by GC and GC,MS, and to test antibacterial efficacy of essential oils and n -hexane, chloroform, acetone and methanol extracts as an antibacterial and seed disinfectant against 25 agricultural plant pathogens. RESULTS: Thymol, carvacrol, p -cymene, thymol methyl ether and ,-terpinene were the main constituents of S. spicigera and T. fallax oils and hexane extracts. The main components of the oil of Achillea millefolium were 1,8-cineole, ,-cadinol and caryophyllene oxide, whereas the hexane extract of this species contained mainly n -hexacosane, n -tricosane and n -heneicosane. The oils and hexane extracts of S. spicigera and T. fallax exhibited potent antibacterial activity over a broad spectrum against 25 phytopathogenic bacterial strains. Carvacrol and thymol, the major constituents of S. spicigera and T. fallax oils, also showed potent antibacterial effect against the bacteria tested. The oils of Achillea species showed weak antibacterial activity. Our results also revealed that the essential oil of S. spicigera, thymol and carvacrol could be used as potential disinfection agents against seed-borne bacteria. CONCLUSION: Our results demonstrate that S. spicigera, T. fallax oils, carvacrol and thymol could become potentials for controlling certain important agricultural plant pathogenic bacteria and seed disinfectant. Copyright © 2009 Society of Chemical Industry [source] Wide variation in effectiveness of laboratory disinfectants against bacteriophagesLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008D.E. Halfhide Abstract Aims:, The purpose of this study was to identify an effective disinfectant for the inactivation of the bacteriophages (phages) being used in our laboratory, as published studies on phage inactivation are far from unanimous in their conclusions. Methods and Results:, The phages studied were three closely related strains of Myoviridae and three strains of Siphoviridae. Three disinfectants which are used commonly in microbiology laboratories were evaluated: Virkon (1%), ethanol (75%) and sodium hypochlorite (2500 ppm available chlorine). The most effective of these was Virkon, which inactivated all six phages rapidly. Ethanol was effective against the Myoviridae but had little effect on the Siphoviridae. Sodium hypochlorite was the least effective of the disinfectants evaluated. Conclusions:, The findings of this study demonstrate a wide diversity in the effectiveness of disinfectants tested for inactivation of phages. Significance and Impact of the Study:, Of the disinfectants tested Virkon is the most suitable choice for those unable to carry out disinfection validation studies, or where a broad spectrum disinfectant against phages is required. All of the phages in this study showed resilience to inactivation by sodium hypochlorite, and therefore this disinfectant is an unwise choice for use against phage without first assessing its effectiveness. [source] Role of Alicyclobacillus acidoterrestris in the development of a disinfectant taint in shelf-stable fruit juiceLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2003N. Jensen Abstract Aims: This study was undertaken to identify the bacterium and metabolic products contributing to a disinfectant taint in shelf-stable fruit juice and to determine some of the growth conditions for the organism. Methods and Results: Microbiological examination of tainted and untainted fruit juice drinks detected low numbers of acid-dependent, thermotolerant, spore-forming bacteria in the tainted juices only. The presence of ,-cyclohexyl fatty acids was confirmed in two of the isolates by cell membrane fatty acid analysis. The isolates were subsequently identified as Alicyclobacillus acidoterrestris by partial 16S rDNA sequencing. Studies on the isolates showed growth at pH 2·5,6·0 and 19·5,58 °C. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP) in the tainted juice. Challenge studies in a mixed fruit drink inoculated with the two isolates and the type strain of A. acidoterrestris, incubated at 44,46 °C for 4 d, showed the production of both metabolites, which were confirmed and quantified by GC/MS. Conclusions: The results show that A. acidoterrestris can produce 2,6-DBP and 2,6-DCP in shelf-stable juices. Significance and Impact of the Study: This is the first report detailing experimental methodology showing that A. acidoterrestris can produce 2,6-DCP in foods. Control of storage temperatures (to <,20 °C) immediately after processing may provide an effective control measure for the fruit juice industry to prevent spoilage by A. acidoterrestris. [source] Combined effects of hot water treatment (HWT) and modified atmosphere packaging (MAP) on quality of tomatoesPACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2003Suparlan Abstract Effects of hot water treatment (HWT) and modified atmosphere packaging (MAP) on quality of tomatoes were studied. Prior to packaging with low-density polyethylene (LDPE) film (0.02,mm in thickness), tomatoes were immersed in hot water (42.5°C) for 30,min. Control tomatoes were not treated and were stored for 2 weeks at 10°C and then for 3 days at 20°C without packaging. Steady states of O2 and CO2 concentrations inside the package were about 5 and 8%, respectively, and were reached after 6 and 4 days of storage, respectively. MAP reduced weight loss of tomatoes to about 41% of that of unpackaged fruit during a 2-week storage period. The use of a combination of HWT and MAP reduced weight loss and decay, inhibited color development and maintained firmness of tomatoes but had no effect on soluble solids content or titratable acidity. HWT slightly reduced mold growth of tomatoes stored in MAP. Packaging of control fruit in MAP resulted in stimulation of mold growth around the stem end of the fruit after about 1 week of storage and also resulted in cracking and decay. HWT could be used as disinfectant for tomatoes prior to storage in MAP in order to reduce microbial growth, cracking and decay that may be caused by excessive water vapor inside the package. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effects of in vitro exposure to ozone and/or hyperoxia on superoxide dismutase, catalase, glutathione and lipid peroxidation in red blood cells and plasma of rainbow trout, Oncorhynchus mykiss (Walbaum)AQUACULTURE RESEARCH, Issue 3 2002O Ritola Abstract In aquaculture, ozone is used as a disinfectant. In its production, extensive amounts of oxygen are formed resulting in hyperoxic conditions in culture units. Both ozone and hyperoxia have the potential to be toxic via pro-oxidant mechanisms and to activate antioxidant defence systems in cultured species. To eliminate systemic effects, blood of rainbow trout, Oncorhynchus mykiss (Walbaum), was exposed in vitro for 5 min to ozone/hyperoxia or hyperoxia, and changes in antioxidant defences and lipid peroxidation were measured after exposure. Ozone exposure caused severe damage in red blood cells (rbc) detected as increased lipid peroxidation and oxidized glutathione (GSSG) levels in both plasma and rbc. Oxygen exposure alone increased intracellular lipid peroxidation and GSSG levels 10 min after exposure and was not evident in the plasma at any time. Ozone, but not oxygen exposure, decreased reduced glutathione (GSH) levels in plasma, and the changes were negatively correlated with increased lipid peroxidation in rbc, indicating that extracellular GSH has a dynamic role in the protection of rbc from direct oxidation by ozone. Both ozone and hyperoxic conditions increased superoxide dismutase (SOD) activity in rbc 3 and 6 h after exposure. In contrast, catalase activity was only increased 10 min after oxygen exposure, suggesting other catalase activation mechanisms rather than enzyme induction. The recovery of lipid peroxidation and GSSG levels in rbc after hyperoxia, but not ozone exposure, indicated a capacity to defend against hyperoxia-produced oxidative damage, but an overwhelming of antioxidant defences by ozone in rainbow trout rbc in vitro. [source] The Bactericidal Effects of Electrolyzed Oxidizing Water on Bacterial Strains Involved in Hospital InfectionsARTIFICIAL ORGANS, Issue 6 2004Nina V. Vorobjeva Abstract:, The study is designed to investigate bactericidal actions of electrolyzed oxidizing water on hospital infec-tions. Ten of the most common opportunistic pathogens are used for this study. Cultures are inoculated in 4.5 mL of electrolyzed oxidizing (EO) water or 4.5 mL of sterile deionized water (control), and incubated for 0, 0.5, and 5 min at room temperature. At the exposure time of 30 s the EO water completely inactivates all of the bacterial strains, with the exception of vegetative cells and spores of bacilli which need 5 min to be killed. The results indicate that electrolyzed oxidizing water may be a useful disinfectant for hospital infections, but its clinical application has still to be evaluated. [source] Light activated disinfection: an alternative endodontic disinfection strategyAUSTRALIAN DENTAL JOURNAL, Issue 2 2009Z Lim Abstract Background:, An improved light activated disinfection technique utilizing a specific photosensitizer formulation, liquid optical-conduit, oxygen-carrier and light energy of appropriate wavelength has been introduced recently. This study tested the efficacy of this improved light activated disinfection on ex vivo biofilms of Enterococcus faecalis at two different stages of maturation. Methods:, Eighty-five tooth sections were prepared and endodontic biofilm of E. faecalis were grown within the root canal. In stage 1, conventional light activated disinfection (LAD), chemical disinfectant (sodium hypochlorite) and improved LAD were tested on four-day-old (immature) biofilms. In stage 2, conventional LAD, improved LAD and chemomechanical disinfection (alone and in combination with improved LAD) were tested on four-week-old (mature) biofilms. Results:, Sodium hypochlorite and improved LAD showed the ability to significantly inactivate bacteria in four-day-old biofilms when compared to the control and LAD (p < 0.05). Inactivation of bacteria from deeper dentine was higher in improved LAD than sodium hypochlorite. In four-week-old biofilms, a combination of chemomechanical disinfection and improved LAD produced significant bacterial killing compared to either chemomechanical disinfection or improved LAD alone. Conclusions:, This study highlighted the potential of improved LAD to kill bacteria within dentinal tubules. In combination with chemomechanical preparation, the improved LAD significantly inactivated four-week-old biofilm bacteria. [source] An evaluation of dermoscopy fluids and application techniquesBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2003A.J. Gewirtzman SummaryBackground Dermoscopy, a noninvasive technique used to help physicians better visualize pigmented skin lesions, is becoming widely used by dermatologists. Yet despite its popularity, to our knowledge basic aspects such as the best immersion fluid (IF) to use and proper procedures for applying the IF and dermatoscope have never been the subject of a systematic investigation. Objectives To determine the best techniques for application of IF and the dermatoscope; to discover which IF results in the least amount of air inclusions; to determine which IF provides the best image quality. Methods and materials This study was divided into three phases. Phase I examined several techniques of taking digital dermoscopic photographs in an attempt to eliminate air bubbles. Phase II tested seven IFs to analyse quantitatively the number of air inclusions for each IF. Phase III investigated these same IFs to judge the image quality for each. Results Phase I: in our hands, the best technique to apply an IF is to use an eyedropper and place the IF directly onto the skin in combination with a ,roll-on technique': the dermatoscope's edge is placed on the skin first and is then rotated until the glass plate lies flat against the skin. Phase II: the alcoholic IF resulted in the least amount of air bubble inclusions (70% ethanol, 90% isopropanol and alcoholic disinfectant), while liquid paraffin (a mineral oil) resulted in the most air bubbles. Phase III: dermoscopic structures were equally clear with alcohols and liquid paraffin, but slightly blurry with ultrasound gel and water. Conclusions Although 90% isopropanol performed slightly better in terms of air inclusions, we prefer to use 70% ethanol in most circumstances because it has the advantage of being odourless, unlike its counterpart. Additionally, ethanol will not stain clothing, does not crystallize on the dermatoscope, disinfects and evaporates immediately (does not need to be wiped off). For certain local considerations, such as dermoscopy on mucosa or the nail, we prefer to use ultrasound gel because it will not flow. [source] OEESC-2005 , Summing up on the theme Irritants and Wet WorkCONTACT DERMATITIS, Issue 6 2006Mari-Ann Flyvholm The aim of this paper was to summarize the presentations and discussions on the theme Irritants and Wet Work at the second conference on Occupational and Environmental Exposures of Skin to Chemicals held in Stockholm June 2005 (OEESC-2005) to bring the focus points to a broader group of professionals and stimulate further discussions. Occupational skin diseases are common diseases with a huge potential for prevention. The risk factors are mostly well known, and the ongoing high occurrence of occupational skin diseases may be seen as a paradox problem. Although all mechanisms involved in occupational skin diseases are not shown throughout, much is known. The existing knowledge justifies the relevance of reducing exposure and introducing prevention programmes. The questions identified for further research included an internationally agreed-upon definition of wet work; better methods to assess the exposure to wet work; the effect of combined exposure to water and water-soluble irritants; the importance of wet work with frequent/short wet,dry cycles versus working longer periods with wet hands; testing skin protection and skin care products; long-term skin effects from alcohol-based hand disinfectants; workplace testing of evidence-based prevention programmes in prospective randomized, controlled intervention studies. [source] Structure,activity relationships for the mutagenicity and carcinogenicity of simple and ,-, unsaturated aldehydesENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2003Romualdo Benigni Abstract Aldehydes are important industrial compounds that are used for the synthesis of chemicals and pharmaceuticals and as solvents, food additives, and disinfectants. Because of their reactivity, aldehydes are able to interact with electron-rich biological macromolecules and adverse health effects have been reported, including general toxicity, allergenic reactions, mutagenicity, and carcinogenicity. The cost, time, and number of animals necessary to adequately screen these chemicals places serious limitations on the number of aldehydes whose health potential can be studied and points to the need of using alternative methods for assessing, at least in a preliminary way, the risks associated with the use of aldehydes. A method of choice is the study of quantitative structure,activity relationships (QSARs). In the present work, we present QSAR models for the mutagenicity and carcinogenicity of simple aldehydes and ,-, unsaturated aldehydes. The models point to the role of electrophilicity, bulkiness, and hydrophobicity in the genotoxic activity of the aldehydes and lend themselves to the prediction of the activity of other untested chemicals of the same class. Environ. Mol. Mutagen. 42:136,143, 2003. © 2003 Wiley-Liss, Inc. [source] Mutagenicity and disinfection by-products in surface drinking water disinfected with peracetic acidENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2002Silvano Monarca Abstract The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to those found with sodium hypochlorite (NaClO) and chlorine dioxide (ClO2). The Ames test, root anaphase aberration assay, and root/micronuclei assay in Allium cepa and Tradescantia/micronuclei test were used to evaluate the mutagenicity of disinfected samples. Microbiological tests were also performed, and disinfection by-products (DBPs) were identified using gas chromatography/mass spectrometry (GC/MS). A slight bacterial mutagenicity was found in raw lake and river water, and similar activity was detected in disinfected samples. A plant test revealed genotoxicity in raw river water, and microbiological analysis showed that PAA has bactericidal activity but lower than that of the other disinfectants. The DBPs produced by PAA were mainly carboxylic acids, which are not recognized as mutagenic, whereas the waters treated with the other disinfectants showed the presence of mutagenic/carcinogenic halogenated DBPs. However, additional experiments should be performed with higher concentrations of PAA and using water with higher organic carbon content to better evaluate this disinfectant. [source] Magnetic Multi-Functional Nano Composites for Environmental ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Jie Dong Abstract A novel concept is proposed to synthesize a new class of composites featuring magnetic, molecular sieve and metallic nanoparticle properties. These multi-functional materials have potential applications as recyclable catalysts, disinfectants and sorbents. The magnetic property enables effective separation of the spent composites from complex multiphase systems for regeneration and recycle, safe disposal of the waste and/or recovery of loaded valuable species. The zeolite molecular sieve provides a matrix which supports a remarkably new, simple, efficient and economical method to make stable, supported silver nanoparticles by silver ion exchange and controlled thermal reduction. The silver nanoparticles generated in this way have excellent properties such as high reactivity and good thermal stability without aggregation, which act as nano reactors for desired functionality in a wide range of applications. Magnetic component (Fe3O4), molecular sieve matrix (zeolite) and silver nanoparticles generated by ion exchange followed by controlled reduction, together form this unique novel composite with designed functions. It represents a practically operational, economical, sustainable and environmentally friendly new advanced functional material. This paper focuses on the novel synthesis and characterization of the composite, with an example of applications as sorbents for the removal of vapor-phase mercury from the flue gas of coal-fired power plants. [source] Use of the modified Robbins device to study the in vitro biofilm removal efficacy of NitrAdineÔ, a novel disinfecting formula for the maintenance of oral medical devicesJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2008T. Coenye Abstract Aims:, To evaluate the use of the modified Robbins device (MRD) to test disinfection strategies against biofilms that form on oral medical devices and to test the biofilm removal efficacy of NitrAdineTM, a disinfectant for the maintenance of oral medical devices. Methods and Results:, Biofilms were grown on discs using the MRD and biofilms formed in this system were used to evaluate the efficacy of NitrAdineTM and to determine the optimal disinfection conditions. Our data indicate that the use of the MRD allows for the rapid and reproducible formation of high-density biofilms. Determination of the efficacy of NitrAdineTM revealed high activity against biofilms tested (e.g. >3 log reduction for Candida albicans and Staphylococcus aureus) and allowed the determination of the optimal conditions for its use. Conclusion:, The high reproducibility and flexibility of the MRD make it an excellent candidate for standardized testing of disinfectants aimed at reducing biofilms on oral medical devices. Using this system, we were able to demonstrate that NitrAdineTM exhibits high activity against biofilms formed by the micro-organisms tested. Significance and Impact of the Study:, Our data suggest that our procedure is appropriate for standardized testing of disinfectants aimed at reducing biofilms on oral medical devices. [source] Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acidJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2005E. Bore Abstract Aims:, To characterize micro-organisms isolated from Norwegian dairy production plants after cleaning and fogging disinfection with alkyl amine/peracetic acid and to indicate reasons for survival. Methods and Results:, Microbial samples were collected from five dairy plants after cleaning and fogging disinfection. Isolates from two of these production plants, which used fogging with alkylamino acetate (plant A), and peracetic acid (plant B), were chosen for further characterization. The sequence of the 16S ribosomal DNA, fatty acid analysis and biochemical characteristics were used to identify isolates. Three isolates identified as Rhodococcus erythropolis, Methylobacterium rhodesianum and Rhodotorula mucilaginosa were isolated from plant A and one Sphingomonas sp. and two M. extorquens from plant B. Different patterns of resistance to seven disinfectants in a bactericidal suspension test and variable degree of attachment to stainless steel were found. The strains with higher disinfectant resistance showed lower degree of attachment than susceptible strains. Conclusions:, The study identifies and characterizes micro-organisms present after cleaning and fogging disinfection. Both surface attachment and resistance were shown as possible reasons for the presence of the isolates after cleaning and disinfection. Significance and Impact of the Study:, These results contribute to the awareness of disinfectant resistance as well as attachment as mechanisms of survival in dairy industry. It also strengthens the argument of frequent alternation of disinfectants in the food processing industry to avoid the establishment of resistant house strains. [source] Intrinsic and acquired resistance to quaternary ammonium compounds in food-related Pseudomonas spp.JOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2003S. Langsrud Abstract Aims: To determine the sensitivity of a strain used for disinfectants testing (Pseudomonas aeruginosa ATCC 15442) and food-associated isolates to benzalkonium chloride and didecyl dimethylammonium chloride (DDAC). To determine whether the increase in bacterial resistance after adaptation to DDAC can be associated with phenotypic changes. To test the activity of alternative disinfectants to eliminate resistant Pseudomonas spp. Methods and Results:Pseudomonas aeruginosa ATCC 15442 was among the most resistant strains tested using a bactericidal suspension test. Growth of a sensitive Ps. fluorescens in gradually higher concentrations of DDAC resulted in stable higher resistance and to some cross-resistance to several antibacterial agents, with the exception of disinfectants containing chloramine T, glutaraldehyde or peracetic acid. It was shown by microscopy that adaptation was followed by loss of flagella, and slime formation. Removal of the slime by sodium dodecyl sulphate resulted in partial loss of the acquired resistance. Conclusions:Pseudomonas spp. may adapt to survive against higher concentrations of quaternary ammonium compounds (QACs), but resistant strains can be eliminated with chemically unrelated disinfectants. Significance and Impact of the Study: The work supports the rotation of disinfectants in food processing environments for avoiding the development of bacterial resistance to QACs. The alternating disinfectants should be chosen carefully, because of possible cross-resistance. [source] Assessment of bismuth thiols and conventional disinfectants on drinking water biofilmsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2003F. Codony Abstract Aims: Biofilms in water distribution systems represent a far more significant reservoir of micro-organisms than the water phase. Biofilms are (i) resistant to disinfectants, (ii) nuclei for microbial regrowth, (iii) a refuge for pathogens, (iv) accompanied by taste and odour problems, and (v) corrode surfaces. The effects of the current strategies for disinfection of drinking water systems in large buildings (chlorination, copper and silver ionization, and hyper-heating) were compared with a new generation of bismuth thiol (BT) biocides. Methods and Results: Multispecies biofilms were treated with 0·8 mg l,1 of free chlorine, 400 and 40 ,g l,1 of copper and silver ions, respectively, at 55 and 70°C, and bismuth-2,3-dimercaptopropanol (BisBAL). Furthermore, the effect of combined heat and BisBAL on planktonic cell viability was examined in monoculture using Escherichia coli suspensions. Inactivation rates for BisBAL were similar to copper,silver ions, where the effects were slower than for free chlorine or temperature. The BisBAL effect on E. coli monocultures was augmented greatly by increasing temperatures. Conclusions: Like copper,silver ions, BTs show more persistent residual effects than chlorine and hyper-heating in water systems. BT efficiency increased with temperature. Like copper,silver ions, BT action is relatively slow. Significance and Impact of the Study: BT presents a new approach to containing water biofilms. BT action is not as rapid, but is more thorough than chlorine, and less caustic. BTs may also be more efficacious in hot water systems. At sub-minimum inhibition concentration levels, BTs uniquely inhibit bacterial exopolysaccharide, thereby retarding biofilm formation. Thus, the combination of bactericidal and residual effects may prevent slime build-up in hot water systems. [source] Disinfection kinetics: a new hypothesis and model for the tailing of log-survivor/time curvesJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2000R.J.W. Lambert A new hypothesis for the understanding of chemical disinfection, which we have termed the Intrinsic Quenching hypothesis, is presented. This mechanistic treatment of disinfection kinetics is based on the hypothesis that the biocide concentration may not be in vast excess over the microbes, as is normally assumed. A mathematical model was developed and found to be useful in describing the observed kinetics of several disinfectants. The model suggested that the reason for the observation of non-linear, log-survivor curves was due to the ability of the microbes, in clean, soil-free conditions, to intrinsically quench the bulk concentration of biocide. [source] Brandeis' Policeman: Results from a Laboratory Experiment on How to Prevent Corporate FraudJOURNAL OF EMPIRICAL LEGAL STUDIES, Issue 2 2008Michael D. Guttentag We use a laboratory experiment to study how to prevent corporate fraud. Our experiment is the first to replicate the salient features of corporate fraud in a controlled setting. We find that requiring additional disclosures significantly reduces fraud. This finding runs counter to implications from previous research, but that research does not include many of the defining aspects of corporate fraud. Our results support the federal government's continued reliance on disclosure as a way to reduce fraud, a reliance that dates back to Louis Brandeis' observation that "publicity is justly commended as a remedy for social and industrial diseases. Sunlight is said to be the best of disinfectants; electric light the most efficient policeman." [source] The effect of disinfectant solutions on the hardness of acrylic resin denture teethJOURNAL OF ORAL REHABILITATION, Issue 7 2003A. C. Pavarina summary, This investigation studied the effects of disinfectant solutions on the hardness of acrylic resin denture teeth. The occlusal surfaces of 64 resin denture teeth were ground flat with abrasives up to 400-grit silicon carbide paper. Measurements were made after polishing and after the specimens were stored in water at 37 °C for 48 h. The specimens were then divided into four groups and immersed in chemical disinfectants (4% chlorhexidine; 1% sodium hypochlorite and sodium perborate) for 10 min. The disinfection methods were performed twice to simulate clinical conditions and hardness measurements were made. Specimens tested as controls were immersed in water during the same disinfection time. Eight specimens were produced for each group. After desinfection procedures, testing of hardness was also performed after the samples were stored at 37 °C for 7, 30, 60, 90 and 120 days. Data were analysed using two-way analysis of variance (anova) and Tukey's test at 95% confidence level. According to the results, no significant differences were found between materials and immersion solutions (P > 0·05). However, a continuous decrease in hardness was noticed after ageing (P < 0·05). It was conclude that the surfaces of both acrylic resin denture teeth softened upon immersion in water regardless the disinfecting solution. [source] Effect of disinfectants containing glutaraldehyde on bonding of a tri- n -butylborane initiated resin to dentineJOURNAL OF ORAL REHABILITATION, Issue 5 2002N. Baba The purpose of this study was to evaluate the effects of disinfectants on the bond strength of resin to dentine. The surface of bovine dentine was exposed to formaldehyde (FA) aqueous solutions, glutaraldehyde (GA) aqueous solutions, 2-hydroxyethyl methacrylate aqueous solutions (HEMA), a commercially available dentine primer (Gluma CPS desensitizer, GLUMA), isotonic sodium chloride solution (IS), and distilled water (DW), and placed in a humidor (HU) at 37 °C, or non-stored (baseline). All dentine surfaces were conditioned with a 10% citric acid and 3% ferric chloride solution (10-3 liquid), and then bonded to an acrylic rod with a self-curing adhesive resin (Super-Bond C&B). The mean tensile bond strengths determined 24 h after bonding were compared by analysis of variance (ANOVA) and Fisher's protected LSD test (n=5, P , 0·05). The exposure of dentine to IS, DW and HU for both 48 and 168 h resulted in a decrease in bond strength when compared with the baseline. The highest bond strengths after 168 h of exposure were obtained with 5% GA, 10% HEMA, and GLUMA, the values of which were equivalent to baseline and were significantly higher than that of FA. It is concluded that disinfectant pre-treatment with 5% GA or GLUMA stabilizes the bonding of tri- n -butylborane (TBB) initiated luting agent to bovine dentine conditioned with 10-3 liquid. [source] The effect of disinfectants on the properties of dental gypsum, part 2: Surface propertiesJOURNAL OF PROSTHODONTICS, Issue 4 2002Khalid M. Abdelaziz PhD Purpose This study is part of an ongoing investigation to evaluate the surface properties of dental stones mixed with disinfection solutions, and to determine the effect of adding gum arabic and calcium hydroxide on the same properties. Materials and Methods Aqueous solutions of 2 chemical disinfectants were used in mixing 2 types of dental stones (type III and type V). These dental stones were modified further by adding 1% gum arabic and 0.132% calcium hydroxide to their hemihydrate powders before mixing. Five specimens prepared from each type of dental stone were classified into 7 groups according to the hemihydrate powder modification and mixing liquid/powder ratio. Surface roughness was tested by 2-dimensional profilometery and scanning electron microscopy (SEM). Knoop hardness testing was carried out, and detail reproduction was assessed using ADA specification 25 in addition to SEM and 3-dimensional profilometer studies. Results Dental stones mixed with chemical disinfectants showed higher average roughness (Ra) values than those of the controls. However, adding gum arabic and calcium hydroxide to the hemihydrate powders before mixing restored values to the level of the control. The additives seemed to have a role in the improvement of surface hardness. There was no significant difference between the experimental and the control group in the terms of detail reproduction. Conclusions Using SEM, 3-dimensional profilometry, and ADA testing methods, we found that the surface roughness of stone casts was adversely affected by using the disinfectant solutions as mixing water substitutes. Gum arabic and calcium hydroxide additives can yield a harder stone surface without compromising other surface properties. [source] Wide variation in effectiveness of laboratory disinfectants against bacteriophagesLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008D.E. Halfhide Abstract Aims:, The purpose of this study was to identify an effective disinfectant for the inactivation of the bacteriophages (phages) being used in our laboratory, as published studies on phage inactivation are far from unanimous in their conclusions. Methods and Results:, The phages studied were three closely related strains of Myoviridae and three strains of Siphoviridae. Three disinfectants which are used commonly in microbiology laboratories were evaluated: Virkon (1%), ethanol (75%) and sodium hypochlorite (2500 ppm available chlorine). The most effective of these was Virkon, which inactivated all six phages rapidly. Ethanol was effective against the Myoviridae but had little effect on the Siphoviridae. Sodium hypochlorite was the least effective of the disinfectants evaluated. Conclusions:, The findings of this study demonstrate a wide diversity in the effectiveness of disinfectants tested for inactivation of phages. Significance and Impact of the Study:, Of the disinfectants tested Virkon is the most suitable choice for those unable to carry out disinfection validation studies, or where a broad spectrum disinfectant against phages is required. All of the phages in this study showed resilience to inactivation by sodium hypochlorite, and therefore this disinfectant is an unwise choice for use against phage without first assessing its effectiveness. 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