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PubMed1990

Blood contamination of anaesthetic and related staff.

The incidence of skin contamination of anaesthetic and related staff by patient's blood and saliva was studied during 270 anaesthetics in Cardiff hospitals over seven continuous days in October 1989. A survey was also made of current Hepatitis B immunisation status and glove-wearing habits of 75 anaesthetists. Blood from 35 (14%) patients caused skin contamination of 65 staff during 46 incidents. Twenty-eight (61%) of the contamination incidents occurred during vessel cannulation. Five (8%) of the 65 staff contaminated by blood already had cuts on their hands. There were nine incidents (4%) of skin contamination by saliva. Fifty-three (71%) anaesthetists were immunised against Hepatitis B. Only seven (9%) anaesthetists wear gloves for oral or nasal intubation, six (8%) for insertion of peripheral venous cannulae, 47 (63%) for insertion of arterial lines and 67 (89%) for insertion of central lines. All anaesthetic and associated staff should wear gloves on a routine basis.

Anesthesiology↗

PubMed1991

Selective purging by human interleukin-2 activated lymphocytes of bone marrows contaminated with a lymphoma line or autologous leukaemic cells.

The ability of recombinant interleukin 2 (rIL2) activated lymphocytes (LAK) to purge BM samples contaminated by tumour cells was evaluated. Human BM mononuclear cells were contaminated with 10% of the lymphoma line CA46 and then cultured in liquid medium containing 1000 U/ml of rIL2 and/or LAK autologous to the used BM. At the end of coculture the growth of residual tumour cells and of CFU-GM were evaluated by clonogenic assay. No tumour cell growth was observed in 5/5 independent experiments after 18 h of coculture with LAK. No significant inhibition of CFU-GM growth was also noted. Subsequently, the effect of LAK on BM obtained from four leukaemic patients and contaminated with 20-50% of their own AML and ALL cells was studied using MAb as a tool for identifying leukaemic cells. LAK eliminated 24-78% of contaminating cryopreserved uncultured autologous leukaemic cells. In five cases the BM was contaminated by a low (2%) amount of ALL cells. In these patients the monoclonal heavy chain rearrangement typical of ALL was no longer visible after coculture with LAK. Evidence for selective tumour cytotoxicity by LAK was confirmed by using autologous BM cells as hot and cold targets in a 51Cr release assay. Finally, successful haematologic reconstitution of lethally irradiated BALB/c mice was obtained using syngeneic BM cocultured with LAK. These results support the investigational use of rIL2 and LAK in the treatment of human leukaemia.

Acute Disease↗

PubMed2005

Amplified-fragment length polymorphism analysis of Propionibacterium isolates implicated in contamination of blood products.

Propionibacterium acnes is implicated in most cases of bacterial contamination of platelet concentrates (PCs). To determine the source of contamination, amplified-fragment length polymorphism (AFLP) analysis was applied. This DNA fingerprinting technique was used to study the molecular relationship of 44 isolates derived from 22 PCs and 22 corresponding red blood cells concentrates (RBCs) from the same whole blood donations. The AFLP results together with sequencing analysis of the 1,200 bp of the 16S ribosomal RNA gene revealed the existence of three main groups: two groups (groups 2 and 3) (55%) consisted of isolates that did not originate from skin flora and another group (group 1) (45%) comprised bacteria belonging to the skin flora. This latter group showed complete homology with reference strains of P. acnes. Therefore these isolates can be considered as P. acnes strains. In contrast, contaminants from groups 2 and 3 were shown to be molecularly unrelated to the P. acnes found on the skin surface. The AFLP is reproducible and gave invaluable information about the nature of Propionibacteria contaminating PCs. To gain more insights into the source of contamination, this technique could be exploited in further studies to determine the molecular relationship of different bacteria commonly found in blood products.

Bacterial Typing Techniques↗

PubMed1983

Plasma contamination accounts for thyroid hormone binding in nuclear protein extracts from human mononuclear cells.

Plasma protein contamination accounted for high affinity thyroid hormone binding to a nuclear protein extract from human blood mononuclear cells. The degree of contamination was directly related to the number of times the cells were washed before the nuclear protein was extracted. After three washes, no specific binding was detected. Plasma contamination was estimated to be 0.3-0.5 microliter/assay tube. The TBG concentration in this volume of plasma was consistent with the concentration of 0.2 micrograms/ml measured by RIA in the nuclear extract. Total specific binding of [125I] T4 and [125I] T3 can be attributed to plasma contamination, as 0.3 microliter of plasma gave identical binding. Furthermore, a TBG antiserum abolished specific T4 and T3 binding to the nuclear protein extract. These data are consistent with TBG being the major plasma contaminant. In fourteen normal, euthyroid subjects, the higher mean maximum binding capacity (MBC) for T4 (1.63 +/- 0.27 SD) compared to T3 (0.25 +/- 0.21 pmol/mg protein; P less than 0.001) and the same binding affinity (Ka, 2.0 +/- 0.7 x 10(9)/mol) for both T4 and T3 are the same as found in plasma. The higher MBC for T4 (5.8 +/- 1.0) and T3 (0.69 +/- 0.2 pmol/mg protein) in two hypothyroid subjects are consistent with the higher mean TBG concentration of 28 +/- 5 micrograms/ml compared to the level in ten normal subjects (19.2 +/- 1.8 micrograms/ml; P less than 0.001). In two subjects with low normal TBG concentrations of 15 micrograms/ml, the T4 maximum specific binding of 9% was lower than found in normal subjects 16.6 +/- 7.6%. We conclude that the methodology described previously and used in this study is invalid for measuring thyroid hormone nuclear receptor status in humans.

Blood Proteins↗

PubMed1986

Laboratory studies on salmonella-contaminated cheese involved in a major outbreak of gastroenteritis.

A major outbreak of gastroenteritis was traced to Cheddar cheese contaminated with Salmonella typhimurium. There were no significant differences in pH values of the contaminated (mean pH 5.31) and non-contaminated (mean pH 5.39) cheese. The isolation rates of Salm. typhimurium were about the same when cheese samples were homogenized in lactose broth, lactose broth containing 1% Tween 80, or in aqueous 2% sodium citrate. Salmonella typhimurium was isolated regardless of preenrichment in lactose broth, but required selective enrichment in selenite cystine or tetrathionate brilliant green broth. There were no marked differences in the isolation rates obtained with different selective enrichment media, or after incubation at 36 degrees and 43 degrees C for 24 or 48 h. Contaminated samples of cheese failed to yield Salm. typhimurium consistently despite large and multiple samplings; samples from the interior of cheese blocks yielded positive results more frequently than the samples from the exterior. The number of Salm. typhimurium in factory sealed blocks as well as in samples obtained from the homes of known cases of salmonellosis was found to range from less than 3/100 g to 9/100 g of cheese. The infective dose of Salm. typhimurium in contaminated cheese was probably no greater than 10(4) organisms, and a rapid decline in numbers of Salm. typhimurium must have occurred subsequent to the outbreak.

Animals↗

PubMed2004

Bioremediation of creosote-contaminated soil in South Africa by landfarming.

AIMS: To determine the combined effects of biostimulation and bioaugmentation in the landfarming of a mispah form (lithosol; food and Agriculture Organisation (FAO)) soil contaminated with >310000 mg kg-1 creosote with a view to developing a bioremediation technology for soils heavily contaminated with creosote. METHODS AND RESULTS: The excavated soil was mixed with 2500 kg ha-1 dolomitic lime and 2000 kg ha-1 mono-ammonium phosphate (MAP) before spreading over a treatment bed of shale reinforced with clay. Sewage sludge (500 kg) was ploughed into 450 m3 of contaminated soil in the second and sixth months of treatment. A further 1000 kg ha-1 MAP was added to the soil at the end of the fifth month. Moisture was maintained at 70% field capacity. Total creosote was determined by the US Environmental Protection Agency (EPA) method 418.1 and concentrations of selected creosote components were determined by gas chromatography/flame ionisation detection (GC/FID). Total creosote was reduced by more than 90% by the 10th month of landfarming. The rate of reduction in creosote concentration was highest after the addition of sewage sludge. The three-ring PAHs were more slowly removed than naphthalene and the phenolic compounds. The four- and five-ring PAHs, although persist until the end of treatment, were reduced by 76-87% at the end of the experiment. CONCLUSIONS: A combination of biostimulation and bioaugmentation during landfarming could enhance the bioremediation of soils heavily contaminated with creosote. SIGNIFICANCE AND IMPACT OF THE STUDY: The study provides information on the management of a combination of biostimulation and bioaugmentation during landfarming, and contributes to the knowledge and database necessary for the development of a technology for bioremediating creosote-contaminated land.

Agriculture↗

PubMed2004

Spatial and temporal changes in microbial community structure associated with recharge-influenced chemical gradients in a contaminated aquifer.

In a contaminated water-table aquifer, we related microbial community structure on aquifer sediments to gradients in 24 geochemical and contaminant variables at five depths, under three recharge conditions. Community amplified ribsosomal DNA restriction analysis (ARDRA) using universal 16S rDNA primers and denaturing gradient gel electrophoresis (DGGE) using bacterial 16S rDNA primers indicated: (i). communities in the anoxic, contaminated central zone were similar regardless of recharge; (ii). after recharge, communities at greatest depth were similar to those in uncontaminated zones; and (iii). after extended lack of recharge, communities at upper and lower aquifer margins differed from communities at the same depths on other dates. General aquifer geochemistry was as important as contaminant or terminal electron accepting process (TEAP) chemistry in discriminant analysis of community groups. The Shannon index of diversity (H) and the evenness index (E), based on DGGE operational taxonomic units (OTUs), were statistically different across community groups and aquifer depths. Archaea or sulphate-reducing bacteria 16S rRNA abundance was not clearly correlated with TEAP chemistry indicative of methanogenesis or sulphate reduction. Eukarya rRNA abundance varied by depth and date from 0 to 13% of the microbial community. This contaminated aquifer is a dynamic ecosystem, with complex interactions between physical, chemical and biotic components, which should be considered in the interpretation of aquifer geochemistry and in the development of conceptual or predictive models for natural attenuation or remediation.

Archaea↗

PubMed2006

Distribution of the Mycobacterium community and polycyclic aromatic hydrocarbons (PAHs) among different size fractions of a long-term PAH-contaminated soil.

Summary Mycobacterium is often isolated from polycyclic aromatic hydrocarbon (PAH)-contaminated soil as degraders of PAHs. In model systems, Mycobacterium shows attachment to the PAH substrate source, which is considered to be a particular adaptation to low bioavailability as it results into increased substrate flux to the degraders. To examine whether PAH-degrading Mycobacterium in real PAH-contaminated soils, in analogy with model systems, are preferentially associated with PAH-enriched soil particles, the distribution of PAHs, of the PAH-mineralizing capacity and of Mycobacterium over different fractions of a soil with an aged PAH contamination was investigated. The clay fraction contained the majority of the PAHs and showed immediate pyrene- and phenanthrene-mineralizing activity upon addition of (14)C-labelled pyrene or phenanthrene. In contrast, the sand and silt fractions showed a lag time of 15-26 h for phenanthrene and 3-6 days for pyrene mineralization. The maximum pyrene and phenanthrene mineralization rates of the clay fraction expressed per gram fraction were three to six times higher than those of the sand and silt fractions. Most-probable-number (MPN)-polymerase chain reaction demonstrated that Mycobacterium represented about 10% of the eubacteria in the clay fraction, while this was only about 0.1% in the sand and silt fractions, indicating accumulation of Mycobacterium in the PAH-enriched clay fraction. The Mycobacterium community composition in the clay fraction represented all dominant Mycobacterium populations of the bulk soil and included especially species related to Mycobacterium pyrenivorans, which was also recovered as one of the dominant species in the eubacterial communities of the bulk soil and the clay fraction. Moreover, Mycobacterium could be identified among the major culturable PAH-degrading populations in both the bulk soil and the clay fraction. The results demonstrate that PAH-degrading mycobacteria are mainly associated with the PAH-enriched clay fraction of the examined PAH-contaminated soil and hence, that also in the environmental setting of a PAH-contaminated soil, Mycobacterium might experience advantages connected to substrate source attachment.

Genes, Bacterial↗

PubMed2004

Influence of petroleum contamination and biostimulation treatment on the diversity of Pseudomonas spp. in soil microcosms as evaluated by 16S rRNA based-PCR and DGGE.

AIMS: The aim of this study was to apply a group specific PCR system followed by denaturing gradient gel electrophoresis (DGGE) analysis to evaluate the effect of oil contamination and the biostimulation process on the diversity of Pseudomonas populations in soil ecosystems. METHODS AND RESULTS: Direct DNA extraction from biostimulated- and oil-contaminated soil samples was performed. Primers specific for the genus Pseudomonas spp. were used to amplify 16S rRNA genes and then a semi-nested PCR reaction was applied to obtain smaller fragments for comparing the PCR products by DGGE. Whether in bulk, oil-contaminated or biostimulated soils, the DGGE profiles revealed little change in Pseudomonas community throughout the 270 days of experiment. The presence of a few additional bands observed only in treated samples indicated that a bacterial shift occurred with the addition of nutrients and with oil contamination. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The combination of semi-nested PCR and DGGE was found to be a rapid and sensitive technique to study the diversity within the genus Pseudomonas and may be suitable for further studies concerning the role of this bacterial group in large-scale oil-contaminated areas.

Ammonium Sulfate↗

PubMed2004

Co-composting of PAH-contaminated soil with poultry manure.

AIMS: To investigate the effects of co-composting poultry manure with soil contaminated with different concentrations of polycyclic aromatic hydrocarbons (PAHs), on the degradation of selected PAHs in a static-pile compost system. METHODS: Mispah form (Food & Agricultural Organisation, FAO : lithosol) soil contaminated with PAHs was co-composted with poultry manure for 19 months. The soil was mixed with wood chips in a ratio of 1:1 to improve aeration and then mixed with poultry manure in a ratio of 4:1. A data logger measured temperature monthly. Residual concentrations of selected PAHs in the compost were determined monthly by gas chromatography/flame ionisation detection (GC/FID). Moisture, pH, ash content and C:N ratios were also monitored monthly. Microbial activity was measured by measuring CO(2) evolution. CONCLUSIONS: The results obtained in this experiment have shown that co-composting poultry manure with PAH-contaminated soil is capable of removing large concentrations of high molecular weight PAH from contaminated soil to levels below 1 mg kg(-1) in 19 months. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper adds to the body of knowledge necessary for the development of a cost effective technology for the remediation of soil contaminated with high molecular weight PAHs by providing information on the behaviour of selected PAHs and factors such as nutrient ratio, temperature and pH during composting.

Animals↗

PubMed1995

Bonding of composite resin to contaminated human enamel and dentin.

PURPOSE: The purpose of this in vitro study was to evaluate the bond strengths of a bonding agent and composite resin system to human enamel and dentin treated with five contaminants (saliva, plasma, zinc oxide-eugenol cement, noneugenol zinc oxide cement, and handpiece lubricant) using air, moisture, and water as controls. MATERIALS AND METHODS: A commercial bonding agent (Gluma 2000; Bayer AG, Dormagen, Germany) and its composite (Pekafill; Bayer AG) were applied to tooth structure under two conditions (contaminated and re-etched). Samples were debonded in tension after 24 hours using an inverted, truncated cone bond test. RESULTS: Among the controls, the highest bond strengths were obtained to enamel (20 MPa) and dentin (12 MPa) with air drying. Contaminants lowered the bond strength by 20% to 100%. Re-etching without additional mechanical preparation resulted in bond strengths similar to the air control. CONCLUSIONS: Bond strength of Gluma 2000/Pekafill to tooth structure is sensitive to common forms of contamination but can be improved by re-etching after contamination occurs.

Acid Etching, Dental↗

PubMed1995

The effects of community pluralism on press coverage of health risks from local environmental contamination.

Based on the conflict/consensus model of Tichenor, Donohue and Olien, we proposed that mass mediated information signalling that local agents are contaminating the local environment and posing health risks is conflict-generating information and, therefore, will be controlled in the interest of community stability. We expected such control to vary by community structure. A content analysis of nine months of coverage by 19 newspapers supported the hypothesis that papers in more pluralistic communities were more likely than papers in less pluralistic communities to link contamination from local agents to threats to human health in the community and to frame such stories as problems. Newspapers in less pluralistic communities were more likely to frame local contamination in the context of solutions to the problem and were more likely to link contamination to health risks if the contamination were in a distant community.

Community Networks↗

PubMed2007

Metabolically active microbial communities in uranium-contaminated subsurface sediments.

In order to develop effective bioremediation strategies for radionuclide contaminants, the composition and metabolic potential of microbial communities need to be better understood, especially in highly contaminated subsurface sediments for which little cultivation-independent information is available. In this study, we characterized metabolically active and total microbial communities associated with uranium-contaminated subsurface sediments along geochemical gradients. DNA and RNA were extracted and amplified from four sediment-depth intervals representing moderately acidic (pH 3.7) to near-neutral (pH 6.7) conditions. Phylotypes related to Proteobacteria (Alpha-, Beta-, Delta- and Gammaproteobacteria), Bacteroidetes, Actinobacteria, Firmicutes and Planctomycetes were detected in DNA- and RNA-derived clone libraries. Diversity and numerical dominance of phylotypes were observed to correspond to changes in sediment geochemistry and rates of microbial activity, suggesting that geochemical conditions have selected for well-adapted taxa. Sequences closely related to nitrate-reducing bacteria represented 28% and 43% of clones from the total and metabolically active fractions of the microbial community, respectively. This study provides the first detailed analysis of total and metabolically active microbial communities in radionuclide-contaminated subsurface sediments. Our microbial community analysis, in conjunction with rates of microbial activity, points to several groups of nitrate-reducers that appear to be well adapted to environmental conditions common to radionuclide-contaminated sites.

Biodegradation, Environmental↗

PubMedDate not supplied

Numerical implementation of a backward probabilistic model of ground water contamination.

Backward location and travel time probabilities can be used to characterize known and unknown sources or prior positions of ground water contamination. Backward location probability describes the position of the observed contamination at some time in the past; backward travel time probability describes the amount of time prior to observation that the contamination was released from its source or was at a particular upgradient location. The governing equation for backward probabilities is the adjoint of the governing equation for contaminant transport, but with new load terms. Numerical codes that have been written to solve the forward equations of contaminant transport, e.g., the advection-dispersion equation, can also be used to solve the adjoint equation for location and travel time probabilities; however, the interpretation of the results is different and some new approximations must be made for the load terms. We present the governing equations for backward location and travel time probabilities, and provide appropriate numerical approximations for these load terms using the cell-centered finite difference method, one of the most popular numerical methods in ground water hydrology. We discuss some additional numerical considerations for the backward model including boundary conditions, reversal of the flow field, and interpretation of the results. We illustrate the implementation of the backward probability model using hypothetical examples in one- and two-dimensional domains. We also present a three-dimensional application of a pump-and-treat remediation capture zone delineation at the Massachusetts Military Reservation. The illustrations are performed using MODFLOW-96 for flow simulations and MT3DMS for transport simulations.

Models, Statistical↗

PubMedDate not supplied

Contaminant transport models under random sources.

While the discussion of model uncertainty has centered on spatial heterogeneity, it is possible that ground water models have not enjoyed much success as predictive tools often because the sources that were eventually imposed in the field differed from those represented in the simulations. This is because deterministic prediction of future conditions is often inaccurate due to the random nature of contaminant sources, in terms of their timing, location, and magnitude. This paper presents a stochastic framework for accommodating random contaminant sources in conventional, deterministic advection-dispersion transport models. The contaminant sources are first classified into two types: those occurring continuously with a deterministic component and random variations and those occurring randomly at instantaneous discrete-time intervals. For the first type, the governing partial differential equation (PDE) is replaced by a stochastic PDE. The random variations are modeled by Gaussian noise or Brownian motion, and the solution is obtained by using Ito's integration technique. For the second type, Markovian analysis is used for discrete-time contamination events. Both approaches use a deterministic transport model to generate response functions at any observation location and time. The response functions are then integrated to yield probabilistic description of contaminant transport, from which key statistical properties such as mean, standard deviation, and confidence interval can be drawn.

Forecasting↗

PubMed2001

Occurrence of pharmaceutical contaminants and screening of treatment alternatives for southeastern Louisiana.

Recent studies conducted in Germany, Switzerland, Denmark, Brazil, Canada, the United States, and elsewhere indicate that low-level concentrations of pharmaceuticals and personal-care products (PPCPs) and their metabolites may be widespread contaminants in our aquatic environment. The persistence of pharmaceutical contaminants has been attributed to (1) human consumption of drugs and subsequent discharges from sewage treatment plants, and (2) veterinary use of drugs and nonpoint discharges from agricultural runoff. Contamination of water resources by these compounds, particularly endocrine disrupting chemicals (EDCs), is emerging as an international environmental concern. The long-term effects of continuous, low-level exposure to PPCPs is not well understood. Preliminary data for raw water samples collected from the Mississippi River and Lake Pontchartrain, Louisiana, are summarized. Three PPCP compounds (clofibric acid, naproxen, and estrone) were analyzed using solid-phase extraction, derivatization, and GC/MS. Batch experiments also were conducted to determine equilibrium capacity of activated carbon for clofibric acid. Preliminary results indicate the occurrence of the selected PPCP contaminants in raw water samples at or near method-detection limits. For batch equilibrium experiments, preliminary results indicate that activated carbon potentially can be used to remove clofibric acid from water. More research is needed to develop rapid and reliable methods for PPCP analysis and to determine the effectiveness of treatment processes for removal of PPCP contaminants in water.

Animals↗

PubMed1979

Possible pathways of contamination of meat and bone meal with Salmonella.

Samples taken at various points along the processing line in 2 rendering plants showed that post-processing contamination occurs almost immediately after termination of the heat process in the percolator and surge bin. Further contamination occurs at each processing stage. In plant A 12.5% of the samples collected from material leaving the surge bin, 36% of the samples of product after it has passed the milling stage and 61% of samples collected from the stored product were found to be contaminated with salmonellas. In plant B the results were 15%, 40% and 69% respectively. Heavy contamination of product left overnight in percolators and surge bins, which are not cleaned routinely, was considered an important source of early post-processing contamination. The ecology was found to be similar at both plants despite the fact that in one plant the uncooked and cooked areas were separated completely, whilst this was not the case in the other plant. None of the air samples collected yielded salmonellas, while nearly all the insect samples collected in the rendering plants yielded salmonellas.

Bone and Bones↗

PubMed1994

Reducing electron contamination for photon beam-quality specification.

The percentage depth dose at 10 cm in a 10 x 10-cm2 photon beam at an SSD of 100 cm, %dd(10), is a better beam-quality specifier for radiotherapy beams than the commonly used values of TPR10(20) or nominal accelerating potential. The presence of electron contamination affects the measurement of %dd(10) but can be removed by the use of a 0.1-cm lead filter, which reduces surface dose from contaminant electrons from the accelerator by more than 95% for radiotherapy beams with energies from 60Co to 50 MV. The filter performs best when it is placed immediately below the head. An electron-contamination correction factor is introduced to correct for electron contamination from the filter and air. It converts the %dd(10) which includes the electron contamination with the filter in place [hereafter %dd(10)m], into %dd(10) for just the photons in the filtered beam. The correction factor is a linear function of %dd(10)m for all filtered beams with %dd(10)m > 70%. A small correction for the photon filtering effect converts the pure photon %dd(10) for the filtered beam into that for the unfiltered beam, which can be used to determine stopping-power ratio. Calculations show that the values of water-to-air stopping power ratio in the unfiltered beam are related to the values of %dd(10)m in the filtered beam by a cubic function. The uncertainty of stopping-power ratios in unfiltered beams for the same value of the %dd(10)m is within 0.2% for all beams.

Cobalt Radioisotopes↗