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PubMed2005

The use of Mytilus galloprovincialis acetylcholinesterase and glutathione S-transferases activities as biomarkers of environmental contamination along the northwest Portuguese coast.

With the aim of using Mytilus galloprovincialis acetylcholinesterase (AChE) and glutathione S-transferases (GST) activities as biomarkers of environmental contamination in risk assessment studies along the northwest Portuguese coast, the objective of this study was to provide background information related to: (1) baseline values of these enzymatic activities both in reference and contaminated areas and their responsiveness as indicators of exposure to environmental contaminants; (2) the importance of seasonal variations of such biomarkers in M. galloprovincialis along this area. For this, the activity of these enzymes was seasonally determined in mussels collected from four sites, including a reference and three stations with different contamination sources along the referred area. Statistically significant differences on both enzymatic activities were found among the four sampling stations, at the four sampling periods. In comparison to the reference station, lower AChE and higher GST activity values were found in mussels collected in stations potentially contaminated by pesticides and domestic/industrial effluents and in mussels collected in the vicinity of an oil refinery and an industrial/mercantile harbour, respectively. The results obtained in this work highlighted the potential suitability of these biomarkers to be used as components of environmental monitoring programs in risk assessment studies along the northwest Portuguese coast. Since a seasonal variation in both enzymatic activities was found, the possible implications of such variability in the use of these enzymes as environmental biomarkers are also discussed.

Acetylcholinesterase↗

PubMed2006

Use of the p,p'-DDD: p,p'-DDE concentration ratio to trace contaminant migration from a hazardous waste site.

For approximately 50 years, beginning in the 1920s, hazardous wastes were disposed in an 11-hectare area of the Marine Corps Base (MCB) Quantico, Virginia, USA known as the Old Landfill. Polychlorinated biphenyls (PCBs) and DDT compounds were the primary contaminants of concern. These contaminants migrated into the sediments of a 78-hectare area of the Potomac River, the Quantico Embayment. Fish tissue contamination resulted in the MCB posting signs along the embayment shoreline warning fishermen to avoid consumption. In this paper, we interpret total PCB (t-PCBs) and total DDT (t-DDT, sum of six DDT, DDD, and DDE isomers) data from monitoring studies. We use the ratio of p,p'-DDD to p,p'-DDE concentrations as a tracer to distinguish site-related from regional contamination. The median DDD/DDE ratio in Quantico Embayment sediments (3.5) was significantly higher than the median ratio (0.71) in sediments from nearby Powells Creek, used as a reference area. In general, t-PCBs and t-DDT concentrations were significantly higher in killifish (Fundulus diaphanus) and carp (Cyprinus carpio) from the Quantico Embayment compared with Powells Creek. For both species, Quantico Embayment fish had mean or median DDD/DDE ratios greater than one. Median ratios were significantly higher in Quantico Embayment (4.6) than Powells Creek (0.28) whole body carp. In contrast, t-PCBs and t-DDT in channel catfish (Ictalurus punctatus) fillets were similar in Quantico Embayment and Powells Creek collections, with median ratios of 0.34 and 0.26, respectively. Differences between species may be attributable to movement (carp and killifish being more localized) and feeding patterns (carp ingesting sediment while feeding). We recommend that environmental scientists use this ratio when investigating sites with DDT contamination.

DDT↗

PubMed2006

Host-specific variation in infection by toxigenic fungi and contamination by mycotoxins in pearl millet and corn.

Pearl millet is widely consumed in regions of Africa and Asia, and is increasingly being grown as an alternative grain in drought-prone regions of the United States. Pearl millet and corn were grown in dryland conditions at Tifton, Georgia, USA and grains were compared for pre-harvest infection by potentially toxigenic fungi and contamination by mycotoxins. Corn hybrids Agripro 9909 and Pioneer 3146, and pearl millet Tifgrain 102 were grown in 2000 and 2001; pearl millet HGM 100 was included in the test in 2001. Hybrids were sown on multiple planting dates in each year to induce variation in flowering time. Host species differed in the frequency of isolation of potentially toxigenic fungal species in both years. Across years, corn hybrids were more prone to infection by Aspergillus flavus Link (maximum isolation frequency = 8.8%) and Fusarium moniliforme Sheldon sensu lato (maximum isolation frequency = 72.8%), with corresponding greater concentrations of aflatoxins (maximum concentration = 204.9 microg kg(-1)) and fumonisins (maximum concentration = 34,039 microg kg(-1)). Pearl millet was more prone to infection by F. semitectum Berk. & Ravenel (maximum isolation = 74.2%) and F. chlamydosporum Wollenweb & Reinking (maximum isolation = 33.0%), and contamination by moniliformin (maximum contamination = 92.1 microg kg(-1)). Beauvericin (maximum concentration = 414.6 microg kg(-1)) was present in both hosts. Planting date of corn affected aflatoxin and beauvericin contamination in 2000, and fumonisin concentration in 2001. The observed differences in mycotoxin contamination of the grains, which are likely due to host-specific differences in susceptibility to pre-harvest mycoflora, may affect food safety when the crops are grown under stress conditions.

Aflatoxins↗

PubMedDate not supplied

Molecular detection of cell line cross-contaminations using amplified fragment length polymorphism DNA fingerprinting technology.

We have tested amplified fragment length polymorphism (AFLP) technology, in comparison with isoenzyme analysis, for the simultaneous detection of inter- and intraspecific cell line cross-contaminations (CCCs) in the cell line collection held at the Istituto Zooprofilattico della Lombardia e dell'Emilia Romagna. Isoenzyme analysis identified four cases of interspecific CCCs. In a single experiment, AFLP was able to identify the species of origin of all cell lines for which a reference genomic deoxyribonucleic acid was available and to detect five interspecific contaminations. Four CCCs confirmed data on isoenzymes, whereas the fifth CCC was detected in a species for which isoenzyme analysis was noninformative. In addition, AFLP was able to identify the putative source of the contaminations detected. The utility of the technology in the detection of intraspecific cell line contaminations depends on the number of cell lines that have to be distinguished in a specific species and on the availability of highly informative fingerprinting systems. In mice, a single AFLP primer pair produced 16 polymorphisms and distinguished all the 15 strains of mouse cell lines analyzed. In humans, 18 AFLPs identified 83 different profiles in the 159 cell lines analyzed. Amplified fragment length polymorphism can conveniently be applied for cell line fingerprinting in species for which hypervariable markers are not available. In species for which a highly informative multiplex of microsatellite markers is available, AFLP can still provide a useful and cheap tool for simultaneously testing inter- and intraspecific contaminations.

Animals↗

PubMed1975

Proteolytic enzymes as adjuncts to antimicrobial prophylaxis of contaminated wounds.

When a tissue is injured, its vessels exhibit a marked increase in vascular permeability. Blood proteins, including fibrinogen, traverse the vessel walls and lead to the development of a surface coagulum. This inflammatory response continues until primary closure of the wound edges is accomplished. The thickness of the surface coagulum is roughly proportional to the time interval between wounding and closure. This coagulum encompasses the surface contaminants, preventing contact with either topical or systemic antibiotics. The presence of this surface coagulum limits the time in which antibiotic prophylaxis is effective. At three hours after injury, antimicrobial prophylaxis of contaminated wounds has no therapeutic value. Hydrolysis of the protein coagulum by proteolytic enzymes enhances the activity of the antibiotic in experimental wounds. The success of proteolytic enzymes as adjuncts to delayed antibiotic treatment can be correlated with the clot lysis activity of the enzymes in vitro. Travase, the most potent fibrinolytic enzyme, is the most effective adjunct to delayed antibiotic therapy of contaminated wounds. In contrast, the active enzymes found in Elase, which exhibit no significant clot lysis activity in vitro, do not potentiate the activity of antibiotics in wounds subjected to a delay in treatment. Travase prolongs the period of effective topical antibiotic action for at least eight hours in experimental contaminated wounds. The therapeutic merit of Travase is also apparent when the antibiotic is administered systemically. Travase shows promise as an adjunct to a variety of antibiotics that are effective against both gram-positive and gram-negative organisms. The results of these experimental studies support our belief that clinical studies support our belief that clinical studies should now be initiated to test the therapeutic value of Travase as an adjunct to antibiotics in heavily contaminated wounds subjected to an unavoidable delay in treatment.

Animals↗

PubMed1976

Blood-brain barrier studies in the rat: an indicator dilution technique with tracer sodium as an internal standard for estimation of extracerebral contamination.

(1)The single injection-indicator dilution method of Crone was adapted for use in the rat. A bolus containing a non-diffusible reference tracer and the test tracer was injected into the internal carotid artery. Simultaneously venous blood was sampled from the confluence of sinuses. It proved necessary to take special steps to avoid extracerebral contamination of the samples. Therefore the extracerebral branches of the carotid tree on both sides were ligated, and the venous sampling was done without suction. Results obtained in animals prepared surgically in different ways were compared. (2) 24Na+ was used to assess the degree of extracerebral contamination, the transcapillary loss of 24Na+ being a sensitive measure since the permeability of cerebral capillaries for sodium is about 4-5% that of muscle. (3) The transcapillary fractional loss, extraction E, was determined in this preparation with minimal extracerebral contamination. ENA+ was 2.9%, Eglucose was 12.5% at normal blood glucose levels whilst the net glucose extraction (calculated from arterio-venous difference) was about 10%. (4) It is concluded that extracerebral contamination is an important pitfall in indicator dilution studies on the brain. Use of 24Na+ as an indicator of extracerebral contamination is therefore recommendable.

Animals↗

PubMed1982

A rapid method for isolation of human mononuclear cells free of significant platelet contamination.

In order to obtain mononuclear cells from peripheral human blood for the study of cell surface receptors, it was necessary to effectively eliminate contaminating platelets. The usual Hypaque-Ficoll isolation procedures were found to produce mononuclear cells contaminated with 10-1000 platelets per mononuclear cell (by phase microscopy). Multiple slow speed centrifugations reduced the contamination to 5-10 platelets per mononuclear cell. However, centrifugation of EDTA-anticoagulated blood through Hypaque (D20(20) 1.060) at 400 X g for 5 min at 22 degrees C followed by the usual Hypaque-Ficoll gradient reduced platelet contamination to less than 1 platelet per 2 mononuclear cells. Thus, a rapid and simple gradient procedure is capable of significantly reducing platelet contamination of mononuclear cell preparations and should facilitate the analysis of mononuclear cell receptors and functions.

Blood Platelets↗

PubMed1993

Effect of tinfoil substitute contamination on adhesion of resin denture tooth to its denture base.

At least one manufacturer claims that contamination of denture teeth with tinfoil substitute during processing is not detrimental. The purpose of this study was to determine whether tinfoil substitute contamination has any significant effect on the bond strength between acrylic resin denture teeth and their processed acrylic resin base. Eighty acrylic resin maxillary central incisors were processed to denture base material. The experimental group had the denture tooth ridgelap area contaminated with tinfoil substitute. The control group was not contaminated. The bond strength of the two groups was tested. The results indicate that contamination with tinfoil substitute significantly reduces the bond strength of acrylic resin denture teeth bonded to their denture base.

Acrylic Resins↗

PubMed1986

The effect of microbial contamination on musculocutaneous and random flaps.

Although musculocutaneous flaps have been shown to have the ability to withstand a greater inoculum of bacteria than random flaps, it has not been shown that the musculocutaneous flap has any greater ability to decrease the bacterial population in a contaminated wound. In this series of experiments, granulating wounds were developed containing 10(4), 10(5), or 10(6) bacteria per gram of tissue. These contaminated wounds were then covered either with musculocutaneous flaps, random flaps, or left uncovered as a control. In the heavily contaminated wounds containing 10(6) bacteria per gram of tissue, neither type of flap was able to prevent bacterial proliferation and all flaps dehisced. In the minimally contaminated wounds containing 10(4) bacteria per gram of tissue, both the musculocutaneous and random flaps achieved wound healing and decreased the bacterial level in the wound. However, in the intermediate group containing 10(5) bacteria per gram of tissue, musculocutaneous flaps lowered the bacterial count and allowed wound closure, whereas the random flaps did not control the bacterial growth and failed. Therefore, in the moderately contaminated wound, musculocutaneous flaps are advantageous and can decrease bacterial counts and obtain successful closure when random flaps cannot.

Animals↗

PubMed1992

The critical relationship of antibiotic dose and bacterial contamination in experimental infection.

Even though the usefulness of prophylactic antimicrobial administration for potentially contaminated operations is widely accepted, infection continues to occur in a finite number of cases. This study examined whether potential infection due to an increasing bacterial inoculum can be prevented or controlled by increasing antimicrobial doses. In an initial set of experiments, Sprague-Dawley rats were given various doses of cefazolin (15, 30, 60, 120 mg/kg) intraperitoneally, then serum and tissue levels were quantified. Serum and tissue drug concentrations correlated with the dose given. In another set of experiments, rats were given doses of either 0, 30 (standard dose), 60, or 120 mg/kg of cefazolin 30 min prior to subcutaneous inoculation of various doses of Staphylococcus aureus. After 6 days, inoculum sites were examined for abscess formation and size. At low levels of contamination, increasing in antibiotic dose to 30, 60, and 120 mg/kg, abscess formation was eliminated at 50, 80, and 92% of inoculum sites, respectively. At moderate levels of contamination, abscesses formed at all inoculum sites, but abscess size was significantly smaller as the dose increased. When a high inoculum of S. aureus was given, large doses of antibiotics provided no additional benefit. These data suggest that the risk of infection in this model of experimental infection is significantly related to the size of the bacterial inoculum. Increasing the dose of an effective antimicrobial increases drug concentration at the site of contamination and reduces the risk of infection. Administration of higher doses of prophylactic antimicrobials may be more effective when larger amounts of bacterial contamination are anticipated.

Abscess↗

PubMed1980

Mathematical study of the contamination phenomenon in the culture of tubercle bacilli.

This paper demonstrates that when 'spot' specimens of sputum are cultured for tubercle bacilli on Löwenstein-Jensen medium, bacterial contamination occurs at random and follows a Poisson distribution. Over a period of 14 years, contamination rates with overnight 'collection' specimens (4.5 to 10.2%) were substantially higher than with spot specimens (1.3 to 4.0%), but the correlation between the two was very high (r = 0.98). In contrast to spot specimens, the incidence of contamination with collection specimens was significantly higher for females than for males, and significant variation was also found between patients of the same sex. In consequence, the Poisson distribution, which assumes a constant contamination rate for all patients, did not provide a satisfactory fit to the data on collection specimens. However, a negative binomial distribution, which incorporates individual variability in contamination rate, provided a good fit. The reasons for individual variability are discussed.

Bacteriological Techniques↗

PubMed1989

A preliminary study of mercury contamination in the surface soil and river sediment of the Roscio District, Bolivar State, Venezuela.

The present study constitutes a comparison of mercury in surface soil and river sediments of a contaminated and an uncontaminated area of Venezuela. In the contaminated area, gold prospectors have been using mercury to separate gold from auriferous sand and rock powders for many years. The baseline level of mercury in the river sediments of the uncontaminated area (Manzanares River, Sucre State) was 0.06 micrograms g-1, while in the contaminated area in the Roscio District of Bolivar State the concentration varied from 0.12 to 129 micrograms g-1. In the river sediments the average level of mercury was 0.71 micrograms g-1 and in the surface soil of the working areas 37 micrograms g-1, which shows a significant increase in the mercury level in the contaminated areas. This high level of mercury in the soil and sediments constitutes a serious risk to public health in the contaminated area, where the local people use the water for drinking and other domestic purposes; moreover, they also consume fish from these rivers.

Geography↗

PubMed1995

Environmental contaminants in caribou in the Northwest Territories, Canada.

Caribou (Rangifer tarandus) are strict herbivores with a winter diet consisting primarily of lichen. This simple food chain makes caribou a good species for monitoring changes in arctic terrestrial ecosystem contamination. The defined ranges of herds across the Northwest Territories (NWT) also enables examination of spatial trends in contaminant exposure. Caribou were collected from five locations in the first half of a study designed to examine levels of a broad spectrum of organochlorine, heavy metal, and radionuclide contaminants. A wide range of contaminants were detected, with most compounds found at relatively low levels. In general, organochlorine residues were significantly lower in caribou from the mainland Bathurst and Qamanirjuaq (Arviat) and the Southampton Island herds than in caribou from Cape Dorset and Lake Harbour on southern Baffin Island. Moderate levels of hexachlorobenzene (HCB) and alpha-hexachlorocyclohexane (alpha-HCH) were detected at all five study sites. HCB residues ranged from a lipid corrected mean of 32.83 ng/g in fat of Bathurst caribou to 129.41 ng/g in Lake Harbour animals. Alpha-HCH levels ranged from 8.11 ng/g in Bathurst animals to 37.9 ng/g in Cape Dorset caribou. Total polychlorinated biphenyl (sigma PCB) residues ranged from 6.24 ng/g in fat of Arviat caribou to 31.68 ng/g in Cape Dorset animals. Congeners 153 and 138 were the most dominant of the 43 congeners tested. Metal levels were also relatively low with the exception of cadmium, which had community means of 9.68- 33.87 micrograms/g in kidney tissue and 1.96-4.39 micrograms/g in liver tissue. Moderate levels of cesium-137 were detected, with community means of 33.2-184.1 Bq/kg in muscle tissue. Long-range atmospheric transport appears to be the primary source of the contaminants detected in this study.

Animals↗

PubMed1995

Presence of airborne contaminants in the wildlife of northern Québec.

As part of the environmental impact studies of the Great Whale and the Nottaway-Broadback-Rupert (NBR) hydroelectric projects, Hydro-Québec collected data on the occurrence and levels of several contaminants present in wildlife from both regions between 1989 and 1991. The analyses performed included metals (mercury, arsenic, selenium, cadmium, lead, nickel and copper), polychlorinated biphenyls (PCBs as arochlors or the sum of 20-40 congeners) and organochlorine pesticides such as hexachlorobenzene (HCB), DDT, DDE, hexachlorocyclohexane (HCH), chlordane, mirex and dieldrin. Species sampled included fish (freshwater and marine), birds (waterfowl, gull and ptarmigan), terrestrial mammals (marten, mink and hare) and marine mammals (freshwater and marine seals, belugas). Most laboratory analyses were carried out on both muscle and liver tissues, but some were conducted on other tissues as well: feathers, eggs and blubber. The results indicate that numerous airborne contaminants were present in the wildlife of both the Great Whale and the NBR study areas and that their level of contamination was similar to that of other northern environments. Total mercury in muscle was high in piscivorous fish, birds and mammals (terrestrial and marine). We observed significant levels of cadmium and lead in the livers of some herbivorous terrestrial animals, such as ptarmigans and hares. Among the organochlorine contaminants analyzed, levels of PCBs and DDE in piscivorous birds (mergansers and loons) and in marine mammals (seals and belugas) were high. For some contaminants, such as mercury, cadmium, lead, PCBs and DDE, the levels observed in some species or tissues could be considered worrisome with regard to public health, if those species or tissues constitute an important part of traditional native diets.

Air Pollutants↗

PubMed1995

Implications of chemical contaminants for aquatic animals in the Canadian arctic: some review comments.

Chemical residue analyses have established beyond doubt that arctic ecosystems are contaminated with low concentrations of several contaminants. The sources of these vary, but for many, the principal source is atmospheric deposition as a result of widespread dispersal by air masses carrying materials from lower latitudes. The principal problem discussed here is how to determine whether there are biological implications associated with the contaminants. For the most part, concentrations are below those found in more temperate regions where similar questions have been asked. Little experimental toxicology has been done with arctic species, and relatively little has been done in environmental toxicology in general to express biological responses in terms of body residues. It is argued that chemical residue studies are not, in themselves, evidence of biological responses. The effects of greatest interest are those at ecological levels, but ecological surveys that might detect biological changes have little power to test for cause-effect linkages between the contaminants and the changes observed. The emerging approach of biomarkers or bioindicators seems to offer the greatest promise for efforts to determine whether arctic contaminants have biological implications.

Animals↗

PubMed1994

A genetic and morphometric comparison of Helisoma trivolvis and Gambusia holbrooki from clean and contaminated habitats.

Genetic and morphometric data from freshwater snail (Helisoma trivolvis) and mosquitofish (Gambusia holbrooki) populations from a relatively clean and a severely contaminated habitat were compared. Within the clean habitat, snail genetic patterns may have been more influenced than those of mosquitofish by site-specific selection because of the lesser likelihood of gene flow among snail subpopulations. Distinct genetic patterns within the contaminated habitat, combined with data from other published work, suggest that selection for tolerant genotypes may have occurred in both species. Body size in both species was associated with glucosephosphate isomerase allozyme genotype. In snails, apparent selection for a particular allele in the contaminated habitat may be related to its contaminant tolerance and body-size plasticity. In mosquitofish, a particular genotype associated with small body size appears to have been favored in the contaminated environment.

Alleles↗

PubMedDate not supplied

Contamination of pig hindquarters with Staphylococcus aureus.

Swab specimens from 4357 pig hindquarters provided for production of cured raw ham were contaminated with Staphylococcus aureus in 22.7%. The bacterial counts for S. aureus on the rind surface of the raw, uncured ham were between 10(1) and 10(3) cfu/cm2 in 89% of the positive samples. In the remaining 11% of contaminated ham counts of 10(3) to 10(6) cfu/cm2 were determined. There were major differences in the rate of contamination between pork from different suppliers. Questioning the suppliers revealed that pork highly contaminated with S. aureus could be traced back to certain abattoirs. This suggests that the technique of slaughter, concomitant hygiene precautions and the subsequent refrigeration of the carcasses affect the contamination of the meat with staphylococci.

Abattoirs↗

PubMed1983

Airborne contamination of wounds in joint replacement operations: the relationship to sepsis rates.

During operations for total joint replacement done in operating rooms with conventional ventilation the mean air contamination varied considerably among the 15 hospitals studied. The range was from 51 to as many as 539 bacteria-carrying particles per cubic metre. When the data from all the hospitals were grouped according to the mean level of bacterial airborne contamination, including operations done in control and in ultraclean air, there was a good correlation between the air contamination and the joint sepsis rate. There was also a correlation between the mean values of air contamination and the numbers of bacteria isolated from wound wash-out samples; but the apparent efficiency of the sampling method varied a great deal among the hospitals carrying out this procedure. From this data it would seem that by far the largest proportion of bacteria found in the wound after the prosthesis had been inserted reached it by the airborne route. With the mean air contamination found in the control series, 164 bacteria-carrying particles per cubic metre, this proportion was as much as 95 per cent. The risk of joint sepsis varied widely among the 19 hospitals. The differences between the highest and lowest being probably as much as 20-fold. However, the effect of an ultraclean air environment was asimilar at all hospitals.

Air Microbiology↗