Decontamination Solutions Research Articles

DNA Decontamination: Novel DNA-ExitusPlus™ in Comparison with Conventional Reagents

Advanced experiments in gene technology demonstrate that even small amounts of free DNA molecules are sufficient to cause infections, re-combinations or biological transformations and new methods with extremely low detection limits for the presence of DNA molecules have been developed. Therefore, detection of DNA contaminations or prevention of amplification artifacts in PCR experiments are essential in all applications. Accordingly, the complete decontamination of equipment and laboratory surfaces from any DNA molecules is important for biological containment and safety. These new developments motivated us to investigate the molecular mechanism of action of our product DNA-Exitus™ in comparison to other commercially available DNA decontamination reagents. Two major problems were apparent: First, none of the conventional reagents destroyed DNA molecules efficiently and second, all reagents contained components with corrosive or even toxic properties. Consequently, we saw the necessity to develop new solutions for effective DNA decontamination. For the first time we present the completely new DNA decontamination reagent DNA-ExitusPlus™. In comparison with conventional products, DNA-ExitusPlus™ guarantees fast and efficient destruction of nucleic acids without corrosive or toxic properties.

Water Decontamination of Chemical Skin/Eye Splashes: A Critical Review

Skin/eye chemical splashes are a significant workplace problem. Initial water decontamination is usually recommended, but there are few well–conducted experimental animal and human studies of efficacy. An extensive review of the literature and other available information sources was performed to define the scope of the problem and critically review the evidence for water decontamination efficacy. Although water decontamination can decrease the severity of chemical skin/eye burns, it cannot completely prevent them. An ideal replacement decontamination solution would be sterile, nontoxic, chelating, polyvalent, amphoteric, and slightly hypertonic to retard skin or corneal penetration of the chemical.

Treatment of spent NTA-based decontamination solutions

Treatment of spent NTA-based decontamination solutions

Análise das atividades dos oito anos iniciais do Banco de Valvas Cardíacas Humanas do Hospital de Caridade da Irmandade da Santa Casa de Misericórdia de Curitiba

OBJETIVO: O objetivo deste trabalho foi avaliar, retrospectivamente, os primeiros oito anos de funcionamento do Banco de Valvas Cardiacas Humanas do Hospital de Caridade da Irmandade da Santa Casa de Misericordia de Curitiba (BVCHSC), analisando aspectos relacionados as atividades de captacao, processamento, armazenamento e distribuicao de enxertos homologos cardiovasculares. METODO: A selecao inicial dos doadores seguiu as diretrizes nacionais para captacao de orgaos humanos, alem de criterios especificos do BVCHSC. Os coracoes foram obtidos de doadores de multiplos orgaos, doadores em parada cardiaca e receptores de transplante cardiaco, com somatoria dos tempos de isquemia inferior a 48 horas. A idade dos doadores variou desde recem-nascidos ate 60 anos para as valvas aorticas e 65 para as pulmonares. Os enxertos dissecados tiveram suas dimensoes mensuradas e sua morfologia avaliada, sendo classificados como categoria 0 (descartados), 1 (alteracoes morfologicas minimas) ou 2 (perfeitos). Foram determinados a incidencia e os germes responsaveis pela contaminacao nos enxertos recebidos, assim como a eficiencia da solucao de descontaminacao. Foram tambem avaliados aspectos relacionados a distribuicao dos enxertos. RESULTADOS: De setembro de 1996 a fevereiro de 2005, 1059 coracoes provenientes de 19 Estados foram recebidos no BVCHSC. Destes, 977 (92,3%) eram de doadores de morte encefalica. Foram processados 2105 enxertos, e dentre os aorticos e pulmonares analisados, 783 eram da categoria 2, 697 pertenciam a categoria 1 e 186 foram descartados por alteracoes morfologicas. No total, 433 enxertos recebidos estavam contaminados, sendo a solucao de antibioticos eficiente na esterilizacao de 330 destes casos. Quinhentos e setenta e um (27,1%) enxertos foram rejeitados em alguma fase do processo, sendo a contaminacao e as alteracoes morfologicas as causas mais frequentes. Foram distribuidos 1338 enxertos para 74 instituicoes de saude do pais, sendo mais comumente empregados na substituicao da valva aortica (529), na correcao de cardiopatias congenitas (478) e durante operacoes de Ross (272). CONCLUSOES: As atividades do BVCHSC durante estes oito anos de funcionamento foram satisfatorias, atingindo os objetivos propostos.

Screening of nitrogen mustards and their degradation products in water and decontamination solution by liquid chromatography–mass spectrometry

Analysing nitrogen mustards and their degradation products in decontamination emulsions posed a significant challenge due to the different phases present in such matrices. Extensive sample preparation may be required to isolate target analytes. Furthermore, numerous reaction products are formed in the decontamination emulsion. A fast and effective qualitative screening procedure was developed for these compounds, using liquid chromatography–mass spectrometry (LC–MS). This eliminated the need for additional sample handling and derivatisation that are required for gas chromatographic–mass spectrometric (GC–MS) analysis. A liquid chromatograph with mixed mode column and isocratic elution gave good chromatography. The feasibility of applying this technique for detecting these compounds in spiked water and decontamination emulsion was demonstrated. Detailed characterisation of the degradation products in these two matrices was carried out. The results demonstrated that N-methyldiethanolamine (MDEA), N-ethyldiethanolamine (EDEA) and triethanolamine (TEA) are not the major degradation products of their respective nitrogen mustards. Degradation profiles of nitrogen mustards in water were also established. In verification analysis, it is important not only to develop methods for the identification of the actual chemical agents; the methods must also encompass degradation products of the chemical agents as well so as to exclude false negatives. This study demonstrated the increasingly pivotal role that LC–MS play in verification analysis.

Use of In Situ-Generated Dimethyldioxirane for Inactivation of Biological Agents

Dimethyldioxirane (DMDO), generated in situ by adding acetone to an aqueous solution containing potassium peroxymonosulfate (Oxone) at neutral pH, was investigated for inactivation of biological warfare agent simulants. The DMDO solution inactivated bacterial spores, fungal spores, vegetative bacterial cells, viruses, and protein by 7 orders of magnitude in less than 10 min. The kill rates of DMDO were more pronounced when compared to kill rates of buffered Oxone alone. Conditions for the use of DMDO as a biological decontaminant were optimized by evaluating the effects of age and temperature on open systems. DMDO effectiveness was compared to that of current decontaminant solutions such as DS2 (used by the U.S. military), bleach, and hydrogen peroxide and was shown to be superior in achieving a 7-log kill of Bacillus atrophaeus, a Bacillus anthracis spore simulant. The results demonstrate the potential for DMDO to fill the need for a noncorrosive, nontoxic, and environmentally safe decontaminant.

Cr(VI) reduction in aqueous solutions by siderite

Hexavalent chromium is a common and toxic pollutant in soils and wastewaters. Reduction of the mobile Cr(VI) to less mobile and less toxic Cr(III) is a solution for decontamination of industrial effluents. In this study, the reduction of hexavalent chromium in aqueous solutions by siderite was investigated. The influences of amount of acid, contact time, siderite dosage, initial Cr(VI) concentration, temperature and particle size of siderite have been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The amount of acid is the most effective parameter affecting the Cr(VI) reduction since carbonaceous gangue minerals consume acid by side reactions. The highest Cr(VI) reduction efficiency (100%) occurred in the 50 mg/l Cr(VI) solution containing two times acid with respect to stoichiometric amount of Cr(VI) and at the conditions of siderite dosage 20 g/l, contact time 120 min and temperature 25 °C. Reduction efficiency increased with increase in temperature and decrease in particle size. The reduction capacity of siderite was found to be 17 mg-Cr(VI)/g.

Detection of prion after decontamination procedures: comparative study of standard Western blot, filter retention and scrapie-cell assay

Prion diseases such as Creutzfeldt-Jakob disease represent a unique infection control problem because the infectious agent exhibits an unusual resistance to conventional chemical and physical decontamination methods. We investigated the reliability and sensitivity of a filter retention assay and standard Western blot to detect the scrapie form of cellular prion protein (PrP Sc), the most commonly used surrogate prion disease marker, on tissue infected samples, treated with five commercially available decontamination solutions currently used in hospitals. Major discrepancies were observed between the two immunoblot methods. By using Western blot, we observed that three decontamination solutions have a strong ability to reduce PrP Sc levels, whereas in the filter assay, none have this effect and two even enhanced the detection of PrP Sc. We used an original and rapid ex vivo approach called the scrapie-cell assay to analyse the persistence of infectivity on scrapie-treated tissues. We observed that tissues remained infectious after treatment with the decontaminant in concordance with in vivo data. This study suggests that conventional PrP Sc detection methods are not adapted for the rapid study of a large number of prion decontaminants tested on infectious tissues, and that the scrapie-cell assay could be proposed as a relevant alternative method.

Bioremediation of 60Co from simulated spent decontamination solutions

Bioremediation of 60Co from simulated spent decontamination solutions by utilizing different biomass of ( Neurospora crassa, Trichoderma viridae, Mucor recemosus, Rhizopus chinensis, Penicillium citrinum, Aspergillus niger and, Aspergillus flavus) fungi is reported. Various fungal species were screened to evaluate their potential for removing cobalt from very low concentrations (0.03–0.16 μM) in presence of a high background of iron (9.33 mM) and nickel (0.93 mM) complexed with EDTA (10.3 mM). The different fungal isolates employed in this study showed a pickup of cobalt in the range 8–500 ng/g of dry biomass. The [Fe]/[Co] and [Ni]/[Co] ratios in the solutions before and after exposure to the fungi were also determined. At micromolar level the cobalt pickup by many fungi especially the mutants of N. crassa is seen to be proportional to the initial cobalt concentration taken in the solution. However, R. chinensis exhibits a low but iron concentration dependent cobalt pickup. Prior saturating the fungi with excess of iron during their growth showed the presence of selective cobalt pickup sites. The existence of cobalt specific sorption sites is shown by a model experiment with R. chinensis wherein at a constant cobalt concentration (0.034 μM) and varying iron concentrations so as to yield [Fe/Co] initial ratios in solution of 10, 100, 1000 and 287 000 have all yielded a definite Co pickup capacity in the range 8–47 ng/g. The presence of Cr(III)EDTA (3 mM) in solution along with complexed Fe and Ni has not influenced the cobalt removal. The significant feature of this study is that even when cobalt is present in trace level (sub-micromolar) in a matrix of high concentration (millimolar levels) of iron, nickel and chromium, a situation typically encountered in spent decontamination solutions arising from stainless steel based primary systems of nuclear reactors, a number of fungi studied in this work showed a good sensitivity for cobalt pickup.

Cyclodextrines as Functional Agents for Decontamination of the Skin Contaminated by Nerve Agents

Three decontamination solutions of beta-cyclodextrines were prepared. Their abilities to decontamine rat skin contamined with nerve agent soman were tested. Decontamination efficacy of the tested cyclodextrine solutions was compared with the same decontamination means but without the cyclodextrines. The efficacy of tested decontaminants was evaluated by the assessment of the ID50 values. Two decontamination prescriptions with cyclodextrines (tetraborate buffer and tetraborate buffer with acetone) do not show significantly better decontamination efficacies in comparison with prescriptions without cyclodextrines. Only in case of aqueous solution of 2-aminoethanol the addition of beta-cyclodextrine resulted in significant increase (32%) in decontamination efficacy.

Inhibitory effect of thyme and basil essential oils, carvacrol, thymol, estragol, linalool and p-cymene towards Shigella sonnei and S. flexneri

There are a few reports on the antimicrobial activity of essential oils or their major constituents towards Shigella sp. The antimicrobial effect of basil and thyme essential oil and its major constituents thymol, p-cymene, estragol, linalool, and carvacrol was determined using the agar well diffusion assay. Thyme essential oil and thymol and carvacrol showed inhibition of Shigella sp. in the agar well diffusion method. The potential of thyme essential oil, thymol and carvacrol at 0.5% and 1.0% v/v for decontamination of lettuce was evaluated. A decrease of the shigellae was observed after washing with 0.5% while at 1% Shigella numbers dropped below the detection limit. However, the antimicrobial effect on a subsequent lettuce sample in the same decontamination solution was significantly decreased. In addition, application of thyme essential oil or thymol or carvacrol for decontamination is hampered by sensoric properties of the lettuce (browning, strong odour).

Development of a method for regeneration of spent electrochemical decontamination solution on the basis of data on speciation of metal ions in solution

This paper describes the method of regeneration of spent electrochemical decontamination solution. The proposed method allows separation of radionuclides and stable metals from spent decontamination solution in a form suitable for final disposal and repeated use of the remaining solution for electrochemical decontamination. Development of this method was based on the results of the speciation studies which showed that Fe(III) can be precipitated in the presence of organic complexing agents, in a form of iron hydroxide, and 110mAg, 60Co, 54Mn radionuclides can be coprecipitated on it. In order to verify the conclusions made as a result of the speciation studies, the experiments with electrochemically prepared simulant solution and real solution were carried out. The test results proved that the proposed method can be applied in practice.

Separation of radionuclides from spent decontamination solutions onto selective inorganic-organic composite absorbers

The experiments were performed to verify the possibility of the direct separation of radionuclides from a liquid decontamination waste. The solution tested were an acidic decontamination solution from the modified AP-Citrox process and a model solution simulating liquid waste from electrochemical decontamination. The efficiency of a set of inorganic absorbers was tested in both batch and dynamic column sorption tests. For the comparison, a strongly acidic cation exchanger (OSTION KS 806) was also tested. From the results obtained it was concluded that neither, composite inorganic absorbers nor strongly acidic cation exchanger can be used for the direct separation of radionuclides from either of both the solutions tested.

Photodegradation of a ternary iron(III)-uranium(VI)-citric acid complex.

The mechanisms of photodegradation of binary iron- and uranium-citrate and ternary iron-uranium-citrate complexes were elucidated. Citric acid degradation products were identified by HPLC and GC, and the metal precipitates were identified by XRD and EXAFS. Photodegradation of a binuclear iron-citrate complex occurred as a result of two one-electron oxidations of citric acid with the formation of 3-oxoglutarate and two ferrous ions. The ferrous ions were reoxidized by a photo-Fenton reaction, resulting in the precipitation of iron as two-line ferrihydrite Fe(OH)3. The citric acid in the uranium-citrate complex underwent a two-electron oxidation to acetoacetate with the concomitant reduction of U(VI) to U(IV). The U(IV) was subsequently photooxidized in the presence of dioxygen with precipitation of uranium as the mineral schoepite (UO3 x 2H2O). A two-step electron reduction of two ferric ions to two ferrous ions wasthe primary mechanism for photodegradation of the ternary iron-uranium-citrate complex with oxidation of citric acid to 3-oxoglutarate; reduction of uranium was not observed. The iron precipitated as ferrihydrite and the uranyl ion as a uranyl hydroxide species. These results show the potential application of photochemical treatment of wastewater and decontamination solutions containing binary and ternary iron- and uranium-citrate complexes.

Handwashing frequencies in an intensive care unit

As most nosocomial infections are thought to be transmitted by the hands of healthcare workers, handwashing is considered the single most important intervention to prevent nosocomial infections. However, previous studies have shown that handwashing practices are poor, especially among medical personnel.The objective of this study was to assess the rate of handwashing among intensive care unit (ICU) healthcare personnel, and then to propose realistic suggestions so that hand hygiene' could be performed at an optimal level. To achieve this, each healthcare worker in the ICU of Istanbul Medical Faculty was observed directly, and, a comprehensive microbiological investigation was carried out among personnel and of the inanimate environment.The frequency of handwashing was low; 12.9% among medical personnel. Moreover, there was a widespread contamination in the ICU and 28.1% of the healthcare workers were carriers for methicillin-resistant Staphylococcus aureus (MRSA). The factors that contributed to low compliance of handwashing protocols were: a low staff to patient ratio, excessive use of gloves and deficiencies in the infra-structure of ICU. In heavy workload conditions, alcoholic handrub solutions for quick hand decontamination can be considered as an alternative to handwashing.

Hydrodynamics of the effectiveness of the AP-CITROX decontamination technology

During the optimization of the AP-CITROX decontamination technology the effect of the different flow rates of the decontamination solutions on the radioactive contamination and corrosion state of stainless steel tube samples originating from steam generators of Paks NPP were studied by a pilot-plant circulation system. The results have proved that a significant increase (up to 2.89 m/s) in the flow rate of the decontamination solution in the 1-5 steps is highly recommended and in order to improve the passivity of the surfaces it should be kept as low as possible (0.5 m/s) during the passivation.

Electrodialysis of Vanadium(III) and Iron(II) Ions from a Simulated Decontamination Solution

The transport of vanadium(III) and iron(II) ions through the Nafion 117 cation-exchange membrane in the presence of picolinic acid was investigated by simulating the equilibrium distribution of ionic species as a function of pH, and by electrodialyzing the simulated waste solution. From distribution calculations of the model reaction systems it could be predicted that at pH 1.6 most vanadium ions exist predominantly in the form of the VIII(Pic−)2 + complex, and this form of complex permeates across the cation-exchange membrane during electrodialysis. The experimental results, including variations in the color and cation concentrations of the catholyte, confirm the existence of the vanadium(III) picolinate complex. Iron ions permeated into the catholyte were converted to their hydroxide precipitates, which could be formed at the high pH condition resulting from the reduction of hydrogen ions and the production of OH− ions by water electrolysis at the cathode. It was also found that the in-situ precipitation of iron in the electrodialyzer could be self-modulated by shifting the catholyte pH from the acidic state to the alkaline state during electrodialysis operation.

OP3A2 - Cytoskeleton perturbations induced by okadaic acid in two human cell lines

A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon Green™, has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO4−2) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t1/2 ≤ 4 min), 1:10 for HD (t1/2 < 2 min with molybdate), and 1:10 for GD (t1/2 < 2 min). The vapor concentrations of GD above the dry sorbent and the sorbent with decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD.

Identification of chemical-weapons-related compounds in decontamination solutions and other matrices by multiple chromatographic techniques

Several applications have arisen for the high confidence identification of chemical weapons agents and related compounds in toxic waste or other complex matrices. Three examples of analysis of agents or byproducts are presented: GA (ethyl N,N-dimethylphosphoramidocyanidate, or tabun) and synthetic byproducts in an complex organic liquid solution; HD [bis(2-chloroethyl)sulfide, or mustard gas] in a decontamination solution; and VX (S,2-diisopropylaminoethyl ethyl methylphosphonothioate) and a toxic hydrolysis product (S,2-diisopropylaminoethyl methylphosphonothioic acid, also known as EA-2192). Multiple chromatographic methods were used to unequivocally identify low concentrations of agent with high confidence, including results from gas chromatographic analysis with mass spectral detection (with electron impact or chemical ionization), infrared detection, atomic emission detection and flame photometric detection, as well as liquid chromatography–tandem mass spectrometry.

Disinfection of human donor corneas during preparation and preservation

Endophthalmitis after penetrating keratoplasty is rare but more frequently observed than after other intraocular procedures. The main source may be a contaminated donor cornea. This survey reviews current concepts of donor globe decontamination and avoidance of infection during preservation. Basically, we suggest the use of a 3% PVP-Iodine solution for decontamination of donor globes. Using short-term preservation techniques, the tissue should be stored at ambient temperature after preparation of corneoscleral disc or before transplantation for a while to allow antibiotics to act against decontaminants. Tissue stored by organ culture should be kept in a sealed vial. Alternatively, the medium may be changed every 10 to 14 days under sterile conditions.