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Differences detected in vivo between samples of aflatoxin-contaminated peanut meal, following decontamination by two ammonia-based processes.

A sample of peanut meal, highly contaminated with aflatoxins, has been subjected to decontamination by two commercial ammonia-based processes. The original contaminated and the two decontaminated meals were fed to rats for 90 days. No lesions associated with aflatoxin-induced hepatocarcinogenesis were detected histologically following feeding with the two detoxified meals. There were, however, clear differences between the two meals in respect of growth rates of the rats. In addition, feeding one of the detoxified meals resulted in hepatic abnormalities detected using novel immunohistochemical reagents. Differences between the two detoxified meals were also indicated by the results of studies using meals 'spiked' with [14C]-aflatoxin B1 prior to being subjected to the detoxification processes. The meals differed in the bioavailability of the label. It was concluded that peanut meal where an initial, unacceptable level of contamination with aflatoxins had been reduced by two ammonia-based processes to comparable, acceptable levels, may still have different effects in vivo when incorporated into animal diets.

Aflatoxins↗

Contamination and decontamination of rat and human skin with plutonium and uranium, studied with a Franz's chamber.

PURPOSE: Our work offers a new method of assessing human skin radiocontamination and of appraising its treatment. This in vitro technique stems from methods used in skin pharmacology. MATERIALS AND METHODS: Franz's diffusion chambers, which help maintain the physiological condition of a skin biopsy, are used to study how 233U and 239Pu, added to a 0.1 N solution of nitric acid, could enter skin. The efficiencies of two different decontaminating agents (Na3Ca)DTPA (25%) and EHBP (0.5 M) are compared. These studies were made on human skin samples, recovered after plastic surgery. Parallel experiments were carried out on hairless rat skin biopsies and on the skin of live hairless rats. RESULTS: Results in vivo and in vitro on the rat were not significantly different which validates the in vitro technique. In human beings, most of the radioactivity was found in the epidermis, with 2-4% found at the level of the dermis. By means of autoradiography we were able to identify that this radioactivity was concentrated in and around hair and sebaceous glands. Local treatments by EHBP seemed more efficient than those by DTPA in decorporating uranium and plutonium but the complexes radionuclide-EHBP seemed to diffuse through the skin more than the radionuclide-DTPA complexes if the skin was not rinsed after application of the chelating agent. CONCLUSION: This new in vitro technique using human skin has been validated for radiotoxicology. It can be used to quantify the diffusion of radionuclides through the various skin layers and to assess the efficiency of decontaminating agents.

Adult↗

Infectivity of prion protein bound to stainless steel wires: a model for testing decontamination procedures for transmissible spongiform encephalopathies.

OBJECTIVES: To establish an animal model to study transmissible spongiform encephalopathy using hamsters and steel wires contaminated with infectious brain materials as transfer vehicles, and, based on this model, to test decontamination procedures against the infectious prion proteins on the steel wires as a near real situation bioassay. DESIGN: Infectious brain materials were given to healthy hamsters intracerebrally either as a suspension or as dried materials on the surface of steel wires. The animals were observed for 18 months. During this period, animals showing definitive clinical signs were euthanized. Decontamination studies were performed by reprocessing contaminated steel wires with different disinfection agents and procedures before implantation. RESULTS: Pathological prion proteins were able to bind to the steel wires and caused disease after the contaminated wires were implanted in the brains of hamsters. When the contaminated wires were treated with different reprocessing procedures before implantation, infectivity was reduced, which was manifested directly by prolonged survival time of the test animals. These results show that this model can be used as a bioassay to validate reprocessing procedures for surgical instruments. CONCLUSIONS: At the time of submission of this article, only the group of hamsters incubated with wires reprocessed with an alkaline detergent, followed by sterilization with a modified cycle in a hydrogen peroxide gas plasma sterilizer (4 injections), showed no clinical signs of disease and remained alive. Two animals from the group receiving sodium hydroxide followed by autoclaving (at 134 degrees C for 18 minutes) died. Furthermore, the tested enzymatic cleaning agent seemed to have no positive effect.

Animals↗

A novel copper-hydrogen peroxide formulation for prion decontamination.

With the appearance of variant Creutzfeldt-Jakob disease (CJD) and the detection of infectious prions in the peripheral organs of persons with sporadic CJD, the development of decontamination methods that are compatible with medical equipment has become a major issue. Here, we show that a formulation of copper metal ions in combination with hydrogen peroxide dramatically reduces the level of prion protein (PrP)(Sc) (the scrapie isoform of PrP) present in homogenates of samples from prion-infected brains, including brain samples from humans with CJD. An animal bioassay confirmed the reduction in prion infectivity, indicating that this novel Cu(2+)-H(2)O(2) formulation has great potential for prion decontamination.

Animals↗

Prevention of Legionella infections in a bone marrow transplant unit: multifaceted approach to decontamination of a water system.

OBJECTIVE: To evaluate measures intended to reduce Legionella infections in patients undergoing bone marrow transplantation (BMT). DESIGN: Ongoing clinical and microbiological surveillance for Legionella colonization or infection was undertaken. All neutropenic patients with pulmonary infiltrates and fever unresponsive to broad-spectrum antibiotics were tested for Legionella organisms. SETTING: A 505-bed medical-surgical hospital with a designated BMT unit. PATIENTS: Two hundred twenty-five patients underwent BMT; 201 were treated on a new BMT unit. The incidence of Legionella infections was compared to that seen in an estimated 150 neutropenic patients treated on other units. INTERVENTION: A combined approach to decontamination of a hospital water supply was assessed. This included heating, particulate filtration, ultraviolet sterilization, and monthly pulse hyperchlorination of water supplied to the BMT unit. The incidence of Legionella infections was assessed on the BMT unit and compared with the frequency elsewhere in the hospital. RESULTS: There were only three cases of Legionella pneumonia among 201 patients undergoing transplantation on a new BMT unit. In contrast, 33 cases of Legionella infections were detected from approximately 150 patients treated on general medical floors. CONCLUSION: A multifaceted approach to decontamination of a hospital water system led to a marked reduction in Legionella infections.

Bone Marrow Transplantation↗

A randomized, double-blind, placebo-controlled trial of selective digestive decontamination in a medical-surgical intensive care unit.

A randomized, double-blind, placebo-controlled trial of selective decontamination of the oropharynx and gastrointestinal tract was conducted on 61 intubated patients in a medical-surgical intensive care unit (ICU) to determine the impact on nosocomial pneumonia, other infections, and emergence of colonization or infection with antibiotic-resistant bacteria. Over 8 months, 30 patients received an oral paste and solution containing polymyxin, gentamicin, and nystatin; 31 patients received a placebo paste and solution. At study entry, patients in both groups were seriously ill (mean acute physiologic score, 27.2), frequently had pulmonary infiltrates (73.8%), and were likely to be receiving systemic antibiotics (86.9%). There were no differences between study patients and control patients in these characteristics or in frequency of any nosocomial infection (50% vs. 55%), nosocomial pneumonia (27% vs. 26%), febrile days (2.3 vs. 2.0), duration of antibiotic therapy (14.0 vs. 13.4), or mortality rates (37% vs. 48%). There was no difference in infections caused by antibiotic-resistant gram-negative bacilli, although a trend towards more frequent infection with gentamicin-resistant enterococci was found for study patients. Selective decontamination did not appear to be effective in our very ill medical-surgical ICU patients, although the number of patients in our trial was sufficient to detect only a 50% or greater reduction in pneumonia rates.

Colistin↗

Selective decontamination of the digestive tract to prevent postoperative infection: a randomized placebo-controlled trial in liver transplant patients.

OBJECTIVE: To determine the efficacy of selective decontamination of the digestive tract (SDD) in patients undergoing elective transplantation of the liver. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Two academic teaching hospitals. PATIENTS: Adult patients undergoing elective liver transplantation: 26 patients receiving SDD and 29 patients receiving a placebo. INTERVENTIONS: Patients undergoing SDD were administered 400 mg of norfloxacin once daily as soon as they were accepted for transplantation. Postoperative treatment for this group consisted of 2 mg of colistin, 1.8 mg of tobramycin, and 10 mg of amphotericin B, four times daily, combined with an oral paste containing a 2% solution of the same drugs until postoperative day 30. Prophylactic intravenous administration of antibiotics was not part of the SDD regimen in this study. Control patients were given a similar regimen with placebo drugs. MEASUREMENTS: The mean number of postoperative bacterial and fungal infections in the first 30 days after transplantation was the primary efficacy end point. Days on a ventilator, days spent in the intensive care unit, and medical costs were registered as secondary outcome variables. MAIN RESULTS: Of the 26 patients undergoing SDD, 22 (84.5%) developed an infection in the postoperative study period; in the placebo group (n = 29), these numbers were not significantly different (25 patients, 86%). The mean number of postoperative infectious episodes per patient was also not significantly different: 1.77 (SDD) vs. 1.93 (placebo). Infections involving Gram-negative aerobic bacteria and Candida species were significantly less frequent in patients receiving SDD (p <.001 and p <.05). Total costs were higher in the group receiving SDD. CONCLUSIONS: Selective decontamination of the digestive tract does not prevent infection in patients undergoing elective liver transplantation and increases the cost of their care. It does, however, affect the type of infection. Infections with Gram-negative bacilli and with Candida species are replaced by infections with Gram-positive cocci.

Adult↗

Selective decontamination of the digestive tract: impact on cytokine release and mucosal damage after hemorrhagic shock.

OBJECTIVE: To determine if selective decontamination of the digestive tract (SDD) influences the proinflammatory immune response of the gut after hemorrhage. DESIGN: Random assignment to either unmanipulated control after 7 days of SDD or conventional rat chow, or hemorrhagic shock group after the same time of conventional rat chow or SDD. SETTING: University animal laboratory. SUBJECTS: Male Wistar rats, weighing between 300 and 350 g. INTERVENTION: Animals of the control group were not manipulated until organ harvesting, whereas animals of the hemorrhagic shock group were bled to 30 +/- 5 mm Hg for 90 mins by withdrawal/reinfusion of shed blood and were resuscitated by Ringer's lactate equivalent to the shed blood volume. MEASUREMENTS AND MAIN RESULTS: Rats were killed after resuscitation (hemorrhagic shock group) or completed feeding (control group). Whole portal and caval blood was obtained, and splenic macrophages and gut mononuclear cells were harvested to measure supernatant tumor necrosis factor-alpha and IL-6 by bioassay. Mesenteric lymph nodes were obtained to determine bacterial translocation, and a histologic specimen was taken from the distal ileum. Feces were harvested to examine the effect of SDD. SDD eliminated Gram-negative enteric bacteria and had no influence on mucosal damage or on bacterial translocation in control animals and animals after hemorrhage. In animals receiving conventional rat chow, hemorrhagic shock led to significantly (p <.05) elevated lipopolysaccharide-stimulated proinflammatory cytokine (tumor necrosis factor-alpha and interleukin-6) release in whole portal blood, splenic macrophages, and gut mononuclear cells compared with the control group without shock. In contrast, hemorrhagic shock after SDD led to suppressed or unchanged cytokine release compared with unmanipulated animals receiving SDD. However, SDD itself induced significant (p <.05) cytokine release in these organs. Furthermore, plasma concentrations of tumor necrosis factor-alpha and interleukin-6 were significantly (p <.05) elevated in animals after hemorrhage and SDD compared with animals after hemorrhage alone. CONCLUSIONS: Hemorrhagic shock led to significant cytokine release. In contrast, cytokine release after hemorrhage and SDD was unchanged or suppressed. Furthermore, in control animals without hemorrhagic shock, SDD induced significant cytokine release. Therefore, selective decontamination of the gut, as practiced in some patients, may induce additional proinflammatory cytokine release, which can add to the proinflammatory burst in case of a complication such as hemorrhagic shock.

Animals↗

Considerations related to the decontamination of houses in Goiânia: limitations and implications.

We are considering some aspects related to the decontamination activities of about 50 houses affected by 137Cs in Goiânia. We describe the way these contaminations occurred, the instruments used, and the procedures. We also discuss the dose limits established for decontamination and the consequences resulting from this action. We call attention to the importance of not only the technical aspects in such activities but also the psychosocial implications resulting from them.

Accidents↗

Decontamination in a Russian settlement.

Decontamination was carried out in an area with three houses in Novo Bobovichi, Bryansk region, Russia, in the autumn of 1995. It was demonstrated that significant reductions in the dose rate both indoor (DRF = 0.34) and outdoor (DRF = 0.20) can be achieved when a controlled cleaning is undertaken. This paper describes the decontamination work carried out and the results obtained. The roofs of the houses were swept and cleaned by special roof cleaning equipment. The soil around the houses was removed by hand while carefully monitoring the ground for residual contamination. By monitoring the decline in the dose rate during the different stages of the work the dose reducing effect of each action has been measured.

Cesium Radioisotopes↗

Skin decontamination of commonly used medical radionuclides.

The increasing use of radionuclides in medical diagnosis raises the possibility of accidental spills and skin contamination. This study was performed to evaluate the effectiveness of several decontaminating agents. Most nuclides were easily removed to levels of less than 5% of their original activity. Sodium pertechnetate (Tc-99m) was the most difficult compound to remove. Little difference was found between the effectiveness of tap water, soap and water, and two commercially available decontaminating agents.

Decontamination↗

PCB-containing transformer fires: decontamination guidelines based on health considerations.

Realization that polychlorinated biphenyl-(PCB)-containing (askarel) transformer fires can produce toxic polychlorinated dibenzofuran (PCDF) and polychlorinated dibenzodioxin (PCDD) isomers has led to efforts to develop guidelines for cleanup of structures contaminated by soot from these fires. Two such fires have occurred in the United States in recent years, one in 1981 in Binghamton, N.Y., the other in 1983 in San Francisco. The phenomenon of PCB transformation to more toxic substances under conditions of uncontrolled combustion was studied in both locations, but much more extensively in New York. In terms of possible danger to human health, PCDFs comprise by far the most important PCB combustion products identified in the soot of both fires. PCDDs were not formed in sufficient quantity in either fire to constitute an important health hazard. The PCDF isomers of greatest health significance are the tetra-, penta-, and hexa- forms having all four lateral positions (2,3,7 and 8) chlorinated. Separate decontamination guidelines were established for each fire, based on different toxicity and exposure assumptions. One guideline was based on carcinogenic risk assessment of 2,3,7,8-TCDD and the other on experimental animal no-observed-effect level data for the same compound. More effort will be required to develop a generally accepted set of askarel fire decontamination guidelines.

California↗

Intestinal decontamination using povidone-iodine compromises small bowel storage quality.

BACKGROUND: Povidone-iodine (PI) (Betadine, Purdue Fredrick Co., Norwalk, CT) is used during pancreas transplantation to provide duodenal decontamination without any intestinal complications. METHODS: This study assessed the combined effect of a luminal pretreatment with PI followed by a proven amino acid (AA)-rich preservation solution on small bowel (SB) storage quality. Rat SB was procured using intra-arterial University of Wisconsin solution followed by luminal administration with combinations of AA+/-PI pretreatment as follows: group 1, 20 mL AA solution; group 2, 20 mL PI and 20 mL AA solution; group 3, 100 mL AA solution; and group 4, 20 mL PI and 100 mL AA solution. Cellular energetics, permeability, and histology were analyzed throughout 10-hr cold storage. RESULTS: After 10 hr, adenosine triphosphate levels remained 2.9 to 3.2 micromol/g protein lower in the PI-treated groups than in groups 1 and 3. Functional parameters were also negatively affected by PI treatment. Mannitol permeability was 203 and 66 nmol/cm2 per hr in groups 2 and 4 versus 46 and 44 nmol/cm2 per hr in groups 1 and 3. Median grades of histologic injury (Park's) at 10 hr were 3, 5.5, 4, and 5 for groups 1 through 4, respectively. Luminal flushing with PI or AA solution resulted in an equivalent clearance greater than 95% of enteric bacteria present. CONCLUSIONS: hort-duration luminal PI exposure potentiates SB injury and provides no improved intestinal decontamination.

Animals↗

A decontamination process to remove metals and stabilise Montreal sewage sludge.

The Montreal Urban Community (MUC) treatment plant produces approximately 270 tons of dry sludge daily (tds/day) during physicochemical wastewater treatment. The sludges are burned and contribute to the greenhouse effect by producing atmospheric CO2. Moreover, the sludge emanates a nauseating odour during its thermal stabilisation and retains unpleasant odours for the part (25%) that is dried and granulated. To solve this particular problem, the treatment plant authorities are currently evaluating an acidic chemical leaching (sulfuric or hydrochloric acid) process at a pH between 2 and 3, using an oxidizing agent such as ferric chloride or hydrogen peroxide (METIX-AC technology, patent pending; [20]). They could integrate it to a 70 tds/day granulated sludge production process. Verification of the application of METIX-AC technology was carried out in a pilot plant set up near the sludge production plant of the MUC. The tests showed that METIX-AC technology can be advantageously integrated to the process used at the MUC. The residual copper (274 +/- 58 mg/kg) and cadmium (5.6 +/- 2.9 mg/kg) concentrations in the treated sludge meet legislation standards. The results have also shown that odours have been significantly eliminated for the dewatered, decontaminated, and stabilized biosolids (> 97%) compared to the non-decontaminated biosolids. A high rate of odour elimination also was obtained for the liquid leached biosolids (> 93%), compared to the untreated liquid biosolids. The fertilising value (N and P) is well preserved by the METIX-AC process. Dissolved organic carbon measurements have showed that little organic matter is brought in solution during the treatment. In fact, the average concentration of dissolved organic carbon measured in the treated liquid phase is 966 +/- 352 mg/l, whereas it is 1190 +/- 325 mg/l in untreated sludge. The treated sludge was first conditioned with an organic polymer and a coagulant aid. It was successfully dewatered with various dehydration equipments (filter press, rotary press, centrifuge).

Canada↗

Health risk assessment after decontamination of the beaches polluted by the wrecked ERIKA tanker.

Following the wreck of the oil tanker ERIKA off the north-west coast of France in December 1999, cleaning up of the beaches involved considerable work, which in any case could not be perfect. This raised the question of the short- and long-term health risks for the future bathers related to the toxicity of the remaining oil polycyclic aromatic hydrocarbons (PAHs). This risk assessment study was conducted to help health authorities plan risk management policies and inform the public. Thirty-six beaches were selected, representing a sample of the most frequently encountered topographic and beach usage situations; seven "control" beaches, unspoiled by ERIKA, were also investigated. Samples of water and sand were taken from each site, as well as from the surface of rocks. The 16 PAHs selected by the U.S. EPA were quantified in each environment. Several scenarios of exposure were contemplated: (1) a child between 2 and 4 years accidentally ingesting a small ball of fuel, (2) a child daily exposed throughout his holiday-time stay, (3) an adult (including a pregnant woman) spending his/her holidays on the coast, (4) an adult working on the beach, (5) and an adult practicing water sports. Among the available and significant toxicological values, the most conservative ones were selected for computing risks. The sand and water, after decontamination, were slightly polluted (respectively, 7.8 microg/kg and 23.3 ng/l of total 16 PAHs), with values similar to those found in the control beaches. By contrast, the rocky areas in some places were still highly polluted (up to 23 mg/kg on the surface layer). No lethal risk was found for a young child who had accidentally ingested a small ball of fuel. The life-long excess risks for skin cancer and for all other cancers were about 10-5 in scenarios including contact with the polluted rocks. In all other cases, excess risks were considerably lower. The hazard quotient for teratogenic effects was very small, except in scenarios where pregnant women would walk among rocks containing high pollution levels. In conclusion, exposure was mainly associated with polluted water among children, and with spoiled rocks for adults. Despite uncertainties, mainly dealing with the prediction of long-term risks following a short-term exposure, this study showed that beaches where pollution was no longer visible after decontamination did not entail any significant health risks and could be opened to the public.

Adult↗

Decontamination with vaporized hydrogen peroxide is effective against Mycobacterium tuberculosis.

AIMS: To determine the efficacy of room fumigation with vaporized hydrogen peroxide (VHP) in decontamination of viable Mycobacterium tuberculosis. METHODS AND RESULTS: About 8 x 10(4)-2.3 x 10(6) CFU of M. tuberculosis H37Rv and M. tuberculosis Beijing were dried in 10-microl drops in tissue culture plates, placed in steam-permeable Tyvek pouches and distributed on laboratory surfaces. The room was exposed to VHP delivered by air conditioning. Different exposure conditions were tested. Exposure to VHP resulted in sterilization of the bacterial samples in three different test runs. CONCLUSIONS: VHP treatment is an effective means of reducing and eliminating room contaminations of M. tuberculosis. SIGNIFICANCE AND IMPACT OF THE STUDY: Fumigation with VHP represents an alternative to formaldehyde fumigation, particularly for decontamination of animal rooms in tuberculosis research laboratories.

Anti-Bacterial Agents↗

Effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration: a histomorphometric study in dogs.

BACKGROUND AND OBJECTIVE: The aim of the present study was to evaluate comparatively the effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration (GTR). MATERIAL AND METHODS: Nine mongrel dogs were used to obtain bilateral chronic class III furcation defects by placing cotton ligatures around both third mandibular premolars. The teeth were randomly assigned to receive one of the following treatments: scaling and root planing, by means of hand and rotatory instruments, in order to remove soft and hard deposits as well as all root cementum (group A); or removal of only soft microbial deposits, by polishing the root surface with rubber cups and polishing paste, aiming for maximum root cementum preservation (group B). Both groups were treated with GTR, with the use of resorbable polyglycolic-lactic acid membranes (RESOLUT XT). RESULTS: Four months later, data analysis showed that a superior length (mm) (3.59 +/- 1.67 and 6.20 +/- 2.26 for groups A and B, respectively; p = 0.004) and a thicker layer (microm) (18.89 +/- 9.47 and 52.29 +/- 22.48 for groups A and B, respectively; p = 0.001) of new cementum was achieved by keeping the root cementum in place during root decontamination (group B). Regardless of the treatment modality, the new cementum was predominantly of a reparative, cellular extrinsic and intrinsic fiber type. CONCLUSION: Within the limits of the present study, it may be concluded that root cementum preservation may affect the new cementum formation following GTR in class III furcation defects, and the treatment modality did not influence the type of newly formed cementum.

Animals↗

Proficiency testing of clinical microbiology laboratories using modified decontamination procedures for detection of nontuberculous mycobacteria in sputum samples from cystic fibrosis patients. The Nontuberculous Mycobacteria in Cystic Fibrosis Study Group.

An improved decontamination method has been demonstrated to reduce overgrowth of mycobacterial media by Pseudomonas aeruginosa and allow the successful recovery of nontuberculous mycobacteria (NTM) from cystic fibrosis (CF) patients. Twenty microbiology laboratories participating in a multicenter investigation designed to determine the significance of NTM in CF patients were required to demonstrate proficiency in the incorporation of this improved method; this was accomplished by successful decontamination and culture workup of a panel of simulated sputum samples seeded with P. aeruginosa and various NTM. All laboratories successfully recovered NTM from samples with acid-fast bacillus (AFB) smear scores of 3+/4+ (i.e., 2 to 18 or > 18 organisms/field). Low-inoculum samples (1+/2+ AFB smears [2 to 18 organisms in 100 or 10 fields]) were problematic in that processed specimens were often smear and/or culture negative.

Bacteriological Techniques↗