Vascular graft infection in the aortoiliac territory - our view in the light of European Society for Vascular Surgery Guidelines the retrospective observation study

INTRODUCTION

Vascular graft infection in the aortoiliac territory (abdominal VGI) is undoubtedly one of the most serious complications in vascular surgery. The treatment is burdened with high mortality and morbidity rates. In 2020, the Guidelines on the Management of Vascular Graft and Endograft Infections were published by the European Society for Vascular Surgery (ESVS). In the light of these guidelines, we decided to review retrospectively all patients who presented to our institution with abdominal VGI.

METHODS

Retrospective observational study of patients presented with abdominal VGI treated in our institution between 20112019 (9 years). The primary goal was to elucidate the rate of vascular graft infection in aortoiliac reconstructions performed between 20112019 and also the mortality rate in the patient cohort operated for this complication. The secondary goals were to evaluate the success rate and the complication rate in different types of reconstructions.

RESULTS

In the defined period between 20112019 we performed 363 open aortoiliac reconstructions. During the same period we treated altogether 15 patients with abdominal VGI, whose primary reconstruction was mostly performed before 2011 (11 patients). In our cohort of patients who underwent reconstruction between 20112019 we observed a graft infection only in 4 cases (1.1%). In the group of 15 patients with abdominal VGI, the male gender prevailed (14 patients). The mean age at the time of primary reconstruction was 61 years. Most of our reconstructions were performed for occlusive disease (14 cases). All infected grafts were aortobifemoral (1 unilateral aortofemoral). They were all late infections with an average presentation time of 61 months since the primary reconstruction (15180 months). Early mortality rate was as high as 27% (4 patients) and overall mortality was 40%. The secondary reinfection rate after primary treatment was 33%.

CONCLUSION

Treatment of abdominal VGI is still burdened with high mortality and morbidity rates. The current ESVS guidelines provide valuable guidance for the diagnosis and management of VGI. It nevertheless remains obvious that the treatment needs to be tailored individually in a multidisciplinary team environment.

Repeatability and Reproducibility of the RTgill-W1 Cell Line Assay for Predicting Fish Acute Toxicity

Predicting fish acute toxicity of chemicals in vitro is an attractive alternative method to the conventional approach using juvenile and adult fish. The rainbow trout (Oncorhynchus mykiss) cell line assay with RTgill-W1 cells has been designed for this purpose. It quantifies cell viability using fluorescent measurements for metabolic activity, cell- and lysosomal-membrane integrity on the same set of cells. Results from over 70 organic chemicals attest to the high predictive capacity of this test. We here report on the repeatability (intralaboratory variability) and reproducibility (interlaboratory variability) of the RTgill-W1 cell line assay in a round-robin study focusing on 6 test chemicals involving 6 laboratories from the industrial and academic sector. All participating laboratories were able to establish the assay according to preset quality criteria even though, apart from the lead laboratory, none had previously worked with the RTgill-W1 cell line. Concentration-response modeling, based on either nominal or geometric mean-derived measured concentrations, yielded effect concentrations (EC50) that spanned approximately 4 orders of magnitude over the chemical range, covering all fish acute toxicity categories. Coefficients of variation for intralaboratory and interlaboratory variability for the average of the 3 fluorescent cell viability measurements were 15.5% and 30.8%, respectively, which is comparable to other fish-derived, small-scale bioassays. This study therefore underlines the robustness of the RTgill-W1 cell line assay and its accurate performance when carried out by operators in different laboratory settings.

Assessment of non-derivatized β-N-methylamino-l-alanine (BMAA) neurotoxin in free form in urine of patients with nonspecific neurological symptoms

The beta-N-methylamino-l-alanine (BMAA) is a non-proteinogenic amino acid discussed to be produced by cyanobacteria forming harmful blooms. Since BMAA is suspected etiological agent in neurodegenerative diseases, there is a need to study and validate whether and in what concentrations can BMAA be present in human tissues. The aim of the present study was to validate analytical and extraction procedures for quantification of non-derivatized BMAA in the urine using liquid chromatography and commercial ELISA Kit. The study was focused on BMAA in different forms - dissolved, protein associated and total. The validated protocol included SPE followed by HILIC MS/MS for analyses of non-derivatized free form of BMAA with a limit of quantification 20 ng/mL. The methods for other BMAA forms (i.e. protein-associated and total) were also assessed but high matrix interferences did not allow their implementation. The method was used for analyses of free BMAA in 23 urine samples from healthy volunteers and psychiatric patients suffering from nonspecific neurological symptoms. Traces of BMAA were suspectedly detected in a single urine sample but they were not unequivocally proved according to all conservative analytical criteria. BMAA was also not confirmed in a repeatedly collected sample from the same person. The evaluated commercial BMAA ELISA Kit (Abraxis) was not suitable for determination of BMAA in extracted urine samples because of systematically highly false positive results. In agreement with recent findings, analyses of BMAA appear to methodologically challenging, and further research on BMAA in human tissues (or its precursors with potency to form BMAA under natural conditions or - eventually - during sample processing) is needed to clarify its potential ethiological role in neurodegenerative diseases.

Bioluminescent Vibrio fischeri Assays in the Assessment of Seasonal and Spatial Patterns in Toxicity of Contaminated River Sediments

Several bacteria-based assays, notably Vibrio fischeri luminescence assays, are often used as environmental monitoring tool for toxicity in sediments that may serve as both sinks and secondary source of contamination in aquatic ecosystems. In this study, we used 30-s kinetic bioassays based on V. fischeri to evaluate the toxicity associated to sediments from five localities with different contamination inputs (Morava River and its tributary Drevnice River in the south-eastern part of the Czech Republic). Toxicity assessed as half maximal inhibitory concentration (IC₅₀) over the course of a year-long sampling was compared in bottom sediments and freshly trapped particulate material. Standard approach based on testing of aqueous elutriates was compared with toxicity of whole sediments (contact suspension toxicity). Bottom sediments showed lower toxicity compared to freshly trapped suspended materials in all cases. On the other hand, standardized elutriates induced generally weaker effects than suspended sediments likely due to losses during the extraction process. Toxicity generally increased during winter reaching maximum peaks in early spring months in all five sites. Total organic carbon (TOC) was found to be highly correlated with toxic effects. Toxicity from sites with direct industrial and agricultural water inputs also correlated with concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Single time point sampling followed by the extraction and testing of elutriates, do not truly reflect the spatial and temporal variability in natural sediments and may lead to underestimation of ecotoxic risks.

Europe-wide survey of estrogenicity in wastewater treatment plant effluents: the need for the effect-based monitoring

A pan-European monitoring campaign of the wastewater treatment plant (WWTP) effluents was conducted to obtain a concise picture on a broad range of pollutants including estrogenic compounds. Snapshot samples from 75 WWTP effluents were collected and analysed for concentrations of 150 polar organic and 20 inorganic compounds as well as estrogenicity using the MVLN reporter gene assay. The effect-based assessment determined estrogenicity in 27 of 75 samples tested with the concentrations ranging from 0.53 to 17.9 ng/L of 17-beta-estradiol equivalents (EEQ). Approximately one third of municipal WWTP effluents contained EEQ greater than 0.5 ng/L EEQ, which confirmed the importance of cities as the major contamination source. Beside municipal WWTPs, some treated industrial wastewaters also exhibited detectable EEQ, indicating the importance to investigate phytoestrogens released from plant processing factories. No steroid estrogens were detected in any of the samples by instrumental methods above their limits of quantification of 10 ng/L, and none of the other analysed classes of chemicals showed correlation with detected EEQs. The study demonstrates the need of effect-based monitoring to assess certain classes of contaminants such as estrogens, which are known to occur at low concentrations being of serious toxicological concern for aquatic biota.

Simultaneous determination of reduced and oxidized glutathione in tissues by a novel liquid chromatography-mass spectrometry method: application in an inhalation study of Cd nanoparticles

The paper presents the development of an advanced extraction and fast analytical LC MS/MS method for simultaneous analyses of reduced and oxidized glutathione (GSH and GSSG, respectively) in different animal tissues. The simultaneous determination of GSH and GSSG is crucial because the amount and ratio of both GSH and GSSG may be altered in response to oxidative stress, an important mechanism of toxicity. The method uses the derivatization of free thiol groups in GSH. Its performance was demonstrated for less explored tissues (lung, brain, and liver) in mouse. The combined extraction and analytical method has very low variability and good reproducibility, maximum coefficients of variance for within-run and between-run analyses under 8 %, and low limits of quantification; for GSH and GSSG, these were 0.2 nM (0.06 ng/mL) and 10 nM (6 ng/mL), respectively. The performance of the method was further demonstrated in a model experiment addressing changes in GSH and GSSG concentrations in lung of mice exposed to CdO nanoparticles during acute 72 h and chronic 13-week exposures. Inhalation exposure led to increased GSH concentrations in lung. GSSG levels were in general not affected; nonsignificant suppression occurred only after the longer 13-week period of exposure. The developed method for the sensitive detection of both GSH and GSSG in very low tissue mass enables these parameters to be studied in cases where only a little sample is available, i.e. in small organisms or in small amounts of tissue.

Do predictions from Species Sensitivity Distributions match with field data?

Species Sensitivity Distribution (SSD) is a statistical model that can be used to predict effects of contaminants on biological communities, but only few comparisons of this model with field studies have been conducted so far. In the present study we used measured pesticides concentrations from streams in Germany, France, and Finland, and we used SSD to calculate msPAF (multiple substance potentially affected fraction) values based on maximum toxic stress at localities. We compared these SSD-based predictions with the actual effects on stream invertebrates quantified by the SPEARpesticides bioindicator. The results show that the msPAFs correlated well with the bioindicator, however, the generally accepted SSD threshold msPAF of 0.05 (5% of species are predicted to be affected) severely underestimated the observed effects (msPAF values causing significant effects are 2-1000-times lower). These results demonstrate that validation with field data is required to define the appropriate thresholds for SSD predictions.

Novel metabolites in cyanobacterium Cylindrospermopsis raciborskii with potencies to inhibit gap junctional intercellular communication

Despite intensive research into toxic bloom-forming cyanobacteria, the majority of their metabolites remain unknown. The present study explored in detail a novel bioactivity identified in cyanobacteria, i.e. inhibition of gap junctional intercellular communication (GJIC), a marker of tumor promotion. The extracellular mixture (exudate) of the cyanobacterial strain Cylindrospermopsis raciborskii (SAG 1.97) was fractionated by semi-preparative reversed phase HPLC, and the fractions assessed for their potencies to inhibit GJIC. Two non-polar fractions that significantly inhibited GJIC were further fractionated, tested and analyzed using multiple mass spectrometric methods. Investigations led to the identification of a putative chemical compound (molecular formula C18H34O3, m/z 299.2581 for the [M+H](+) ion) responsible for observed bioactivities. Specific inhibitors of signaling pathways were used to screen for biochemical mechanisms beyond GJIC inhibition, and the results indicate the involvement of ERK1/2 kinases via a mechanism related to the action of epidermal growth factor EGF but clearly distinct from other anthropogenic tumor promoters like polychlorinated biphenyls or polycyclic aromatic hydrocarbons. The chemical and in vitro toxicological characterizations of the newly described metabolite provide important insights into the still poorly understood health impacts of complex toxic cyanobacterial blooms and indicate that currently applied monitoring practices may underestimate actual risks.

Estrogen-, androgen- and aryl hydrocarbon receptor mediated activities in passive and composite samples from municipal waste and surface waters

Passive and composite sampling in combination with in vitro bioassays and identification and quantification of individual chemicals were applied to characterize pollution by compounds with several specific modes of action in urban area in the basin of two rivers, with 400,000 inhabitants and a variety of industrial activities. Two types of passive samplers, semipermeable membrane devices (SPMD) for hydrophobic contaminants and polar organic chemical integrative samplers (POCIS) for polar compounds such as pesticides and pharmaceuticals, were used to sample wastewater treatment plant (WWTP) influent and effluent as well as rivers upstream and downstream of the urban complex and the WWTP. Compounds with endocrine disruptive potency were detected in river water and WWTP influent and effluent. Year-round, monthly assessment of waste waters by bioassays documented estrogenic, androgenic and dioxin-like potency as well as cytotoxicity in influent waters of the WWTP and allowed characterization of seasonal variability of these biological potentials in waste waters. The WWTP effectively removed cytotoxic compounds, xenoestrogens and xenoandrogens. There was significant variability in treatment efficiency of dioxin-like potency. The study indicates that the WWTP, despite its up-to-date technology, can contribute endocrine disrupting compounds to the river. Riverine samples exhibited dioxin-like, antiestrogenic and antiandrogenic potencies. The study design enabled characterization of effects of the urban complex and the WWTP on the river. Concentrations of PAHs and contaminants and specific biological potencies sampled by POCIS decreased as a function of distance from the city.

Estrogenic activity in extracts and exudates of cyanobacteria and green algae

Here is presented some of the first information on interactions of compounds produced by cyanobacteria and green algae with estrogen receptor signaling. Estrogenic potency of aqueous extracts and exudates (culture spent media with extracellular products) of seven species of cyanobacteria (10 different laboratory strains) and two algal species were assessed by use of in vitro trans-activation assays. Compounds produced by cyanobacteria and algae, and in particular those excreted from the cells, were estrogenic. Most exudates were estrogenic with potencies expressed at 50% of the maximum response under control of the estrogen receptor ranging from 0.2 to 7.2 ng 17β-estradiol (E(2)) equivalents (EEQ)/L. The greatest estrogenic potency was observed for exudates of Microcystis aerigunosa, a common species that forms water blooms. Aqueous extracts of both green algae, but only one species of cyanobacteria (Aphanizomenon gracile) elicited significant estrogenicity with EEQ ranging from 15 to 280 ng 17β-estradiol (E(2))/g dry weight. Scenedesmus quadricauda exudates and extracts of Aphanizomenon flos-aquae were antagonistic to the ER when coexposed to E(2). The EEQ potency was not correlated with concentrations of cyanotoxins, such as microcystin and cylindrospermopsin, which suggests that the EEQ was comprised of other compounds. The study demonstrates some differences between the estrogenic potency of aqueous extracts prepared from the same species, but of different origin, while the effects of exudates were comparable within species. The observed estrogenic potencies are important namely in relation to the possible mass expansion of cyanobacteria and release of the active compounds into surrounding water.

Enantioselective effects of alpha-hexachlorocyclohexane (HCH) isomers on androgen receptor activity in vitro

Alpha-hexachlorocyclohexane (alpha-HCH), a part of the HCH pesticide mixture, is one of the most widespread persistent organic pollutants. Interestingly, only limited number of studies addressed the toxicity of alpha-HCH and the effects of its individual optical isomers have not been investigated in detail. In the present study we separated two alpha-HCH enantiomers by preparative HPLC and studied their activities towards androgen receptor (AR) using the MDA-kb2 cell line stably transfected with the luciferase reporter gene under the control of AR. There was no direct effect of alpha-HCH on AR but both isomers significantly suppressed the activity of AR in co-exposure with the natural ligand dihydrotestosterone in a concentration-dependent manner. One of the enantiomers appeared to be more active at lower concentration, which was also supported by the molecular modeling calculations with AR that showed a slight difference in estimated free energy of binding and inhibition constant between two enantiomers. Although studies with other pesticides demonstrated strong enantioselective differences in toxicity, the present research shows rather minor differences in modulations of AR by both alpha-HCH enantiomers. For the first time, enantioselective effects of alpha-HCH were demonstrated and the results suggest interaction with multiple regulatory events controlling the AR activity. Full elucidation of the toxicity mechanism will require further research.

In vitro modulation of intracellular receptor signaling and cytotoxicity induced by extracts of cyanobacteria, complex water blooms and their fractions

The biological activity of cyanobacteria and their chemical components have been widely studied due to their blooms in eutrophic waters worldwide. The primary goal of this study was to determine if individual cyanobacterial species and mixtures of cyanobacteria collected from the environment contain compounds with the potential for interaction with signaling pathways of the aryl hydrocarbon receptor (AhR), androgen receptor (AR), estrogen receptor (ER), glucocorticoid receptor (GR) and retinoid acid receptor (RAR). Cytotoxicity and specific toxic potencies of products of freshwater cyanobacteria were determined by use of in vitro reporter gene trans-activation assays. The testing included samples prepared from five selected single cyanobacterial species cultivated in laboratory and five complex cyanobacterial biomasses collected from blooms in surface waters in the Czech Republic. The results demonstrate estrogenic potencies of extracts of cyanobacterial biomasses. Among the laboratory single species, the extract of Planktothrix agardhii (intracellular metabolites) had a potency of estrogenic equivalents (EEQ) of 3.8 ng 17β-estradiol/g dw. The estimates of EEQs of samples prepared from complex cyanobacterial biomasses collected from freshwaters in the Czech Republic ranged from 19 to 2200 ng 17β-estradiol/g dw. Several samples prepared from the environmental cyanobacterial biomasses potentiated the androgenic potency of dihydrotestosterone. There was no dioxin-like, glucocorticoid or anti/retinoic activity observed for any of the extracts studied. Extracts of natural complex cyanobacterial biomasses exhibited greater and more frequent presence of compounds with specific modes of action, mainly estrogenic, and also greater cytotoxicity than extracts of single cyanobacterial species. The demonstrated estrogenic potency of the compounds present in complex cyanobacterial biomasses is of environmental relevance, and could potentially contribute to endocrine disruptive effects in aquatic ecosystems in case of great bloom densities.

[Determination of airborne and surface contamination with cyclophosphamide at the Masaryk Memorial Cancer Institute, Brno, Czech Republic]

Manipulation with cytotoxic drugs (CDs) during the preparation and administration of chemotherapy to cancer patients can potentially lead to contamination of working areas and consequently to occupational exposure of hospital staff. This study aimed to assess the potential of inhalation and dermal contact with CDs. For this purpose, distribution of the marker drug (cyclophosphamide, CP) in the working environment of the Masaryk Memorial Cancer Institute (Czech Republic) was studied. The study determined airborne and surface contamination of the hospital pharmacy and the outpatient clinic. Determination of airborne contamination was based on active stationary sampling of air using a PTFE filter, an impinger filled with distilled water and two solid sorbent tubes (Anasorb 708 and Strata-X) as sampling devices. Surface contamination was determined by the wipe sampling method. The airborne contamination was rare and the concentrations were many times lower than the maximal value calculated from the vapour pressure (0.36 mg/m3 at 20 degrees C). Detectable airborne CP was found in Strata-X samples collected at the outpatient clinic (n = 5, all samples positive at concentrations from 0.3 to 4.3 ng/m3). Surface contamination was determined at 75% of wipe samples (n = 65) with a median concentration of 750 ng/m2. In conclusion, inhalation of CDs seems to be of low importance at our hospital, which is up to the standard specified by current legislation (drug preparation performed in a clean room equipped with negative pressure isolators). The main proportion of contamination was present on the surfaces at all workplaces studied. Consequently, attention should be given to the elimination of the sources of surface contamination and to the prevention of dermal contact with contaminated material.

Mitochondrial toxicity of microcystin-LR on cultured cells: application to the analysis of contaminated water samples

Microcystins (MC) are potent hepatic toxins delivered into the cells by organic anion transporting peptides (OATP) where they target protein phosphatases and mitochondria. We analyzed the effects of MC-LR on primary hepatocytes, HepG2, and Jurkat T cells, and isolated rat liver mitochondria by measuring changes in O(2) consumption by optical oxygen sensing technique. Respiration of fresh primary hepatocytes was inhibited by MC-LR with EC50 = 2.74 +/- 0.65 nM, whereas an uncoupling effect on mitochondrial state 2 and state 3 respiration was observed with glutamate/malate as a substrate. HepG2 and Jurkat T cells lacking OATP showed no sensitivity to MC-LR; however, facilitated delivery of MC-LR resulted in a marked enhancement of HepG2 O(2) consumption and inhibition of Jurkat O(2) consumption at >or=0.1 nM. The respiratory response did not coincide with changes in viability, total cellular ATP, extracellular acidification, ROS formation, or protein phosphorylation, which were detectable at higher MC-LR doses. Such prominent effect on cellular respiration was therefore used for the detection of MC-LR in environmental samples. A simple and sensitive screening assay for MC-LR toxicity was developed, which uses Jurkat cells, facilitated delivery of the toxin(s) and measurement on a fluorescent reader. The assay was applied to a panel of environmental samples suspected to contain MC and benchmarked against the ELISA test. It allowed identification of toxic samples and quantification of both nonspecific and MC-LR type of toxicity.

Kinetic bacterial bioluminescence assay for contact sediment toxicity testing: relationships with the matrix composition and contamination

The present study represents the first broader evaluation of the rapid 30-s kinetic bioluminescence assay with Vibrio fisheri (microplate format modification) for contact toxicity testing of whole sediments. The present study focused on river sediments from the Morava River basin, Czech Republic, repeatedly sampled during 2005 to 2006 and analyzed for geological and geochemical parameters, content of toxic metals, major organic pollutants, and toxicity. High natural variation in toxicity (50% inhibitory concentration [IC50] values ranging from 0.8 to >80 mg sediment dry wt/ml) was found (among different sampling periods and years, among sites), and this could be related to the sediment dynamics affected by spring high flows and summer droughts. From the 46 sediment descriptors, exchangeable protons (H(+)) was the only parameter that consistently correlated with toxicity. Three other descriptors (i.e., content of organic carbon plus two parameters from the detailed silicate analysis of sediments: percentage of SO(3) representing total sulfur content, structural water H(2)O+) also significantly correlated with toxicity. There were only minor and variable correlations with contamination. We propose sediment safety guideline categories for the V. fisheri kinetic test with severe toxicity threshold of IC50 < 1 mg dry wt/ml. Although sediments are considered a rather stable matrix in comparison with river water, we confirmed high variability and dynamics that should be reflected in monitoring plans and field studies.

[Evaporation of selected cytotoxic drugs and permeation of protective gloves--research into the occupational risks of health care personnel handling hazardous cytotoxic drugs (CYTO project)]

BACKGROUNDS

The CYTO project studies an important aspect of healthcare provision -long-term occupational exposure, both threshold and below-threshold, to chemical agents with carcinogenic and mutagenic properties, with the major focus on antineoplastic drugs.This contribution presents experimental results from the first stages of the project's experimental work, i.e. an evaluation of the physico-chemical characteristics of cytostatic agents (evaporation) and an investigation into protective glove permeation.

MATERIALS AND METHODS

In co-operation with IUTA (Institut für Energie- und Umwelttechnik e.V., Duisburg, Germany), the vapour pressure of paclitaxel, doxorubicin and dacarbazine was measured following OECD guideline No. 104: Vapour pressure curve--vapour pressure balance. Furthermore, the evaporation of cytostatic drugs was examined in actual laboratory conditions by monitoring the airborne concentration using the passive sampling technique. Besides the evaporation of selected drugs, the permeation of cisplatin, cyclophosphamide, doxorubicin, 5-fluorouracil and paclitaxel through different types of gloves (vinyl, latex, nitrile) was assessed.

RESULTS

Although our experiments showed relatively slow evaporation of the evaluated cytostatic drugs (the highest pressure in paclitaxel was 0.024 Pa), equilibrium concentrations may go up to milligrams per cubic metre. Nevertheless, analytical measurements of airborne contamination did not confirm these concentration levels. The glove permeation experiments with cytostatics showed good resistance of nitrile gloves (which were impermeable to all five drugs). Other materials should be avoided while handling cytostatic agents (e.g. maximum permeation of cyclophosphamide through latex was 19 microg/sq cm/hr).

CONCLUSION

Although the volatility of cytostatic agents is low, it cannot be neglected considering the chronic character of exposure. However, in order to estimate actual occupational exposure, future research should focus on the development of sensitive analytical methods. Nevertheless, dermal uptake is supposed to be the major route of exposure and use of protective gloves is necessary to minimize potential risks. Our simulated time-dependent permeation experiments with cytostatic agents and different glove materials showed that good protection is provided only by nitrile gloves. The results obtained in this study will be used for the modelling of exposure doses and health risk assessment in the subsequent stages of the CYTO research project.

Endocrine effects of contaminated sediments on the freshwater snail Potamopyrgus antipodarum in vivo and in the cell bioassays in vitro

Lake Pilnok located in the black coal-mining region Ostrava-Karvina, Czech Republic, contains sediments highly contaminated with powdered waste coal. Moreover, population of the endangered species of narrow-clawed crayfish Pontastacus leptodactylus with high proportion of intersex individuals (18%) was observed at this site. These findings motivated our work that aimed to evaluate contamination, endocrine disruptive potency using in vitro assays and in vivo effects of contaminated sediments on reproduction of sediment-dwelling invertebrates. Chemical analyses revealed low concentrations of persistent chlorinated compounds and heavy metals but concentrations of polycyclic aromatic hydrocarbons (PAH) were high (sum of 16 PAHs 10 microg/g dw). Organic extracts from sediments caused significant in vitro AhR-mediated activity in the bioassay with H4IIE-luc cells, estrogenicity in MVLN cells and anti-androgenicity in recombinant yeast assay, and these effects could be attributed to non-persistent compounds derived from the waste coal. We have also observed significant in vivo effects of the sediments in laboratory experiments with the Prosobranchian euryhaline mud snail Potamopyrgus antipodarum. Sediments from Lake Pilnok as well as organic extracts of the sediments (externally added to the control sediment) significantly affected fecundity during 8 weeks of exposure. The effects were stimulations of fecundity at lower concentrations at the beginning of the experiment followed by inhibitions of fecundity and general toxicity. Our study indicates presence of chemicals that affected endocrine balance in invertebrates, and emphasizes the need for integrated approaches combining in vitro and in vivo bioassays with identification of chemicals to elucidate ecotoxicogical impacts of contaminated sediment samples.

Selected endocrine disrupting compounds (vinclozolin, flutamide, ketoconazole and dicofol): effects on survival, occurrence of males, growth, molting and reproduction of Daphnia magna

BACKGROUND, AIM AND SCOPE

Pollution-induced endocrine disruption in vertebrates and invertebrates is a worldwide environmental problem, but relatively little is known about effects of endocrine disrupting compounds (EDCs) in planktonic crustaceans (including Daphnia magna). Aims of the present study were to investigate acute 48 h toxicity and sub-chronic (4-6 days) and chronic (21 days) effects of selected EDCs in D. magna. We have investigated both traditional endpoints as well as other parameters such as sex determination, maturation, molting or embryogenesis in order to evaluate the sensitivity and possible use of these endpoints in ecological risk assessment.

MATERIALS AND METHODS

We have studied effects of four model EDCs (vinclozolin, flutamide, ketoconazole and dicofol) on D. magna using (i) an acute 48 h immobilization assay, (ii) a sub-chronic, 4-6 day assay evaluating development and the sex ratio of neonates, and (iii) a chronic, 21 day assay studying number of neonates, sex of neonates, molting frequency, day of maturation and the growth of maternal organisms.

RESULTS

Acute EC50 values in the 48 h immobilization test were as follows (mg/L): dicofol 0.2, ketoconazole 1.5, flutamide 2.7, vinclozolin >3. Short-term, 4-6 day assays with sublethal concentrations showed that the sex ratio in Daphnia was modulated by vinclozolin (decreased number of neonate males at 1 mg/L) and dicofol (increase in males at 0.1 mg/L). Flutamide (up to 1 mg/L) had no effect on the sex of neonates, but inhibited embryonic development at certain stages during chronic assay, resulting in abortions. Ketoconazole had no significant effects on the studied processes up to 1 mg/L.

DISCUSSION

Sex ratio modulations by some chemicals (vinclozolin and dicofol) corresponded to the known action of these compounds in vertebrates (i.e. anti-androgenicity and anti-oestrogenicity, respectively). Our study revealed that some chemicals known to affect steroid-regulated processes in vertebrates can also affect sublethal endpoints (e.g. embryonic sex determination and/or reproduction) in invertebrates such as D. magna.

CONCLUSIONS

A series of model vertebrate endocrine disrupters affected various sub-chronic and chronic parameters in D. magna including several endpoints that have not been previously studied in detail (such as sex determination in neonates, embryogenesis, molting and maturation). Evaluations of traditional reproduction parameters (obtained from the 21 day chronic assay). as well as the results from a rapid, 4-6 day, sub-chronic assay provide complementary information on non-lethal effects of suspected organic endocrine disrupters.

RECOMMENDATIONS AND PERSPECTIVES

It seems that there are analogies between vertebrates and invertebrates in toxicity mechanisms and in vivo effects of endocrine disruptors. However, general physiological status of organisms may also indirectly affect endpoints that are traditionally considered 'hormone regulated' (especially at higher effective concentrations as observed in this study) and these factors should be carefully considered. Further research of D. magna physiology and comparative studies with various EDCs will help to understand mechanisms of action as well as ecological risks of EDCs in the environment.

Tumor promoting properties of a cigarette smoke prevalent polycyclic aromatic hydrocarbon as indicated by the inhibition of gap junctional intercellular communication via phosphatidylcholine-specific phospholipase C

Inhibition of gap junctional intercellular communication (GJIC) and the activation of intracellular mitogenic pathways are common hallmarks of epithelial derived cancer cells. We previously determined that the 1-methyl and not the 2-methyl isomer of anthracene, which are prominent cigarette smoke components, activated extracellular receptor kinase, and inhibited GJIC in WB-F344 rat liver epithelial cells. Using these same cells, we show that an immediate upstream response to 1-methylanthracene was a rapid (<1 min) release of arachidonic acid. Inhibition of phosphatidylcholine-specific phospholipase C prevented the inhibition of GJIC by 1-methylanthracene. In contrast, inhibition of phosphatidylinositol specific phospholipase C, phospholipase A(2), diacylglycerol lipase, phospholipase D, protein kinase C, and tyrosine protein kinases had no effect on 1-methylanthracene-induced inhibition of GJIC. Inhibition of protein kinase A also prevented inhibition of GJIC by 1-methylanthracene. Direct measurement of phosphatidylcholine-specific phospholipase C and sphingomyelinase indicated that only phosphatidylcholine-specific phospholipase C was activated in response to 1-methylanthracene, while 2-methylanthracene had no effect. 1-methylanthracene also activated p38-mitogen activated protein kinase; however, like extracellular kinase, its activation was not involved in 1-methylanthracene-induced regulation of GJIC, and this activation was independent of phosphatidylcholine-specific phospholipase C. Although mitogen activated protein kinases were activated, Western blot analyzes indicated no change in connexin43 phosphorylation status. Our results indicate that phosphatidylcholine-specific phospholipase C is an important enzyme in the induction of a tumorigenic phenotype, namely the inhibition of GJIC; whereas mitogen activated protein kinases triggered in response to 1-methylanthracene, were not involved in the deregulation of GJIC.

Polychlorinated naphthalenes and other dioxin-like compounds in Elbe River sediments

Contamination of Elbe River (Germany) sediments with dioxin-like toxicants was investigated following the 500-year flood (flood that statistically occurs once in 500 years) of 2002. It was hypothesized that large amounts of particulate matter from river beds and associated dioxin-like toxicants were mobilized and transported during this flood event. The investigation focused on polychlorinated naphthalenes (PCNs) that have not been determined previously in the Elbe River. The in vitro H4IIE-luc assay was used as an overall measure for toxicants capable of binding to the aryl hydrocarbon receptor (AhR). The assay was combined with congener-specific instrumental analyses and fractionation to quantify PCN contributions to total AhR-mediated activity relative to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Penta- to octachloronaphthalene concentrations of 30 ng/kg dry weight up to 13 microg/kg dry weight were found in Elbe River sediments downstream of Bitterfeld. Concentrations of penta- to octachloronaphthalenes, however, were only approximately 3 microg/kg dry weight at a site in the vicinity of Bitterfeld, where a level of approximately 3 mg/kg dry weight was reported before the flood. Also, the congener pattern of PCNs at this site changed after the flood, and PCN patterns reported previously for Bitterfeld and assigned to chlor-alkali electrolysis with graphite electrodes could now be observed at the sites from downstream of Bitterfeld and Magdeburg. Whereas PCDD/Fs dominated the dioxin-like activity in the middle and lower Elbe River, PCNs contributed as much as 10% of the total AhR-mediated activity. The contribution of PCBs was less significant (maximum, 0.2%). Thus, in Elbe River sediments, PCNs should be considered as relevant contaminants and be included in future monitoring and risk assessment programs.

Isolation and endotoxin activities of lipopolysaccharides from cyanobacterial cultures and complex water blooms and comparison with the effects of heterotrophic bacteria and green alga

Massive cyanobacterial water blooms are serious environmental and health problems worldwide. While some cyanobacterial toxins such as peptide microcystins have been investigated extensively, other toxic components of cyanobacteria (e.g. lipopolysaccharides, LPS) are poorly understood. The present study characterized endotoxin activities of LPS isolated from (i) laboratory cyanobacterial cultures, (ii) cyanobacterial water bloom samples dominated by Microcystis sp., Planktothrix sp., Aphanizomenon sp. and Anabaena sp., (iii) heterotrophic Gram-negative bacteria Escherichia coli, Kluyvera intermedia, Pseudomonas putida and Pseudomonas fluorescens and (iv) green alga Pseudokirchneriella subcapitata. Toxicity results derived with Limulus amebocyte lysate assay (LAL-test) showed that endotoxin activities of LPS from both cyanobacteria and heterotrophic bacteria were comparable and the values were within a similar range (1 x 10(3)-1 x 10(6) Endotoxin Units, EU, per mg of isolated LPS). The highest activities among the cyanobacterial samples were observed in the Aphanizomenon sp. dominated water bloom. The results also suggest generally higher endotoxin activities in complex natural samples than in laboratory cyanobacterial cultures. Further, experiments with the eukaryotic green alga P. subcapitata demonstrated a need for careful purification of the LPS extracts prior to testing with the LAL assay as several contaminants may overestimate endotoxin activities. This study shows relatively high pyrogenicity of LPS from various cyanobacteria. Further research should focus on detailed toxicological and ecotoxicological characterization of LPS in massive cyanobacterial water blooms.

Microcystin kinetics (bioaccumulation and elimination) and biochemical responses in common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix) exposed to toxic cyanobacterial blooms

Two species of common edible fish, common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), were exposed to a Microcystis spp.-dominated natural cyanobacterial water bloom for two months (concentrations of cyanobacterial toxin microcystin, 182-539 microg/g biomass dry wt). Toxins accumulated up to 1.4 to 29 ng/g fresh weight and 3.3 to 19 ng/g in the muscle of silver carp and common carp, respectively, as determined by enzyme-linked immunosorbent immunoassay. Concentrations an order of magnitude higher were detected in hepatopancreas (up to 226 ng/g in silver carp), with a peak after the initial four weeks. Calculated bioconcentration factors ranged from 0.6 to 1.7 for muscle and from 7.3 to 13.3 for hepatopancreas. Microcystins were completely eliminated within one to two weeks from both muscle and hepatopancreas after the transfer of fish with accumulated toxins to clean water. Mean estimated elimination half-lives ranged from 0.7 d in silver carp muscle to 8.4 d in common carp liver. The present study also showed significant modulations of several biochemical markers in hepatopancreas of fish exposed to cyanobacteria. Levels of glutathione and catalytic activities of glutathione S-transferase and glutathione reductase were induced in both species, indicating oxidative stress and enhanced detoxification processes. Calculation of hazard indexes using conservative U.S. Environmental Protection Agency methodology indicated rather low risks of microcystins accumulated in edible fish, but several uncertainties should be explored.

Ecotoxicity and genotoxicity assessment of cytostatic pharmaceuticals

The fate and effects of cytostatic (anticancer or antineoplastic) pharmaceuticals in the environment are largely unknown, but they can contaminate wastewater treatment effluents and consequently aquatic ecosystems. In this paper, we have focused on five cytostatic compounds used in high amounts (cyclophosphamide, cisplatin, 5-fluorouracil, doxorubicin, and etoposide), and we have investigated their ecotoxicity in bacterial Pseudomonas putida growth-inhibition test, algal Pseudokirchneriella subcapitata growth-inhibition test, and Dapnia magna acute immobilization test. Genotoxicity also was assessed with Escherichia coli SOS-chromotest (with and without metabolic activation) and the GreenScreen Assay using yeast S. cerevisiae. All tested compounds showed significant effects in most of the assays with lowest-observed-effect concentrations and concentrations causing 50% effects (EC50s) values ranging within microg/L to mg/L. The most toxic compound was 5-fluorouracil in the assays with P. putida (EC50 = 0.027 mg/L) and P. subcapitata (EC50 = 0.11 mg/L), although cisplatin and doxorubicin were the most toxic to D. magna (EC50 = 0.64 and 2.0 mg/L, respectively). These two chemicals were also the most genotoxic in the SOS-chromotest (minimum genotoxic concentrations [MGC] = 0.07-0.2 mg/L), and 5-fluorouracil was the most genotoxic in the eukaryotic yeast assay (MGC = 0.02 mg/L). Our investigation seems to indicate generally lower risks of acute effects at concentrations expected in the environment. However, some effective concentrations were relatively low and chronic toxicity of cytostatics (and/or their transformation products), as well as specific sources of human pharmaceuticals such as hospital effluents, require research attention.

Interference of contaminated sediment extracts and environmental pollutants with retinoid signaling

Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis. Some effects, such as malformations in frogs or changes in metabolism of birds, could be related to disruption of the retinoid signaling pathway by exposure to organic contaminants. A new reporter gene assay has been established for evaluation of the modulation of retinoid signaling by individual chemicals or environmental samples. The bioassay is based on the pluripotent embryonic carcinoma cell line P19 stably transfected with the firefly luciferase gene under the control of a retinoic acid-responsive element (clone P19/ A15). The cell line was used to characterize the effects of individual chemicals and sediments extracts on retinoid signaling pathways. The extracts of sediments from the River Kymi, Finland, which contained polychlorinated dioxins and furans and polycyclic aromatic hydrocarbons (PAHs), significantly increased the potency of all-trans retinoic acid (ATRA), while no effect was observed with the extract of the sediment from reference locality. Considerable part of the effect was caused by the labile fraction of the sediment extracts. Also, several individual PAHs potentiated the effect of ATRA; on the other hand, 2,3,7,8-tetrachlorodibenzo-p-dioxin and several phthalates showed slightly inhibiting effect. These results suggest that PAHs could be able to modulate the retinoid signaling pathway and that they could be responsible for a part of the proretinoid activity observed in the sediment extracts. However, the effects of PAHs on the retinoic acid signaling pathways do not seem to be mediated directly by crosstalk with aryl hydrocarbon receptor.

AhR-mediated and antiestrogenic activity of humic substances

Humic substances (HS) were for decades regarded as inert in the ecosystems with respect to their possible toxicity. However, HS have been recently shown to elicit various adverse effects generally attributed to xenobiotics. In our study, we used MVLN and H4IIE-luc cell lines stably transfected with luciferase gene under control of estrogen receptor (ER) and Ah receptor (AhR; receptor connected with so-called dioxin-like toxicity) for assessment of anti/estrogenic and AhR-mediated effects of 12 commercially available humic substances. Out of those, five humic acids were shown to induce AhR-mediated activity with relative potencies related to TCDD 2.6 x 10(-8)-7.4 x 10(-8). Organic extracts of HS solutions also elicited high activities what means that lipophilic molecules are responsible for a great part of effect. However, relatively high activity remaining in extracted solution suggests also presence of polar AhR-agonists. Contribution of persistent organic compounds to the observed effects was ruled out by H(2)SO(4) treatment. Eight out of twelve HS elicited significant antiestrogenic effects with IC(50) ranging from 40 to 164 mg l(-1). The possible explanations of the antiestrogenic effect include sorption of 17-beta-estradiol (E2) on HS, changes in membrane permeability for E2 or another specific mechanism.

Effect of different cyanobacterial biomasses and their fractions with variable microcystin content on embryonal development of carp (Cyprinus carpio L.)

While numerous studies focused on the effects of microcystins, the role of other components of complex cyanobacterial water blooms in toxicity is poorly understood. In this study we have evaluated effects of various fractions of cyanobacterial biomass with different composition and microcystin content on embryolarval development of carp (Cyprinus carpio). The following samples (fractions) of four natural water blooms were prepared and tested: complex cyanobacterial biomass, crude aqueous extract of biomass, cellular pellet remaining from aqueous extract, permeate (i.e. microcystin-free fraction prepared during C-18 solid-phase extraction; SPE), and eluate (i.e. fraction prepared by SPE containing mostly microcystins). Complex biomass and the crude aqueous extract (regardless of microcystin content and/or microcystin variants present) in the sample were the most toxic. On the other hand, eluate fractions of all samples containing microcystins in concentrations 8-255 microgL(-1) induced no or only weak toxic effects. Exposures of fish to permeate fractions (with removed microcystins) of two samples dominated by Aphanizomenon sp. and Planktothrix sp. resulted in significant mortality, while other two samples dominated by Microcystis spp. induced minor effects. We have also observed significant inhibition of glutathione S-transferases (GST) at most fractions of the Aphanizomenon sp. and Planktothrix sp. dominated samples. Our data indicate that cyanobacterial water blooms as well complex biomass extracts induce significant embryolarval toxicity in common carp. However, these effects were independent of microcystin content, and the most pronounced effects were observed with the non-Microcystis dominated samples. Therefore, a critical examination of microcystin role in overall ecotoxicology of complex cyanobacterial blooms is needed.

Toxicity of complex cyanobacterial samples and their fractions in Xenopus laevis embryos and the role of microcystins

This work evaluated the effects of various cyanobacterial fractions in Frog Embryo Teratogenesis Assay Xenopus (FETAX) with African clawed frog embryos. Fractions were prepared from five biomasses with different dominant genera (Microcystis, Aphanizomenon, Anabaena, Planktothrix) and different microcystin content. Effects of following fractions were investigated: (I) homogenate of complex cyanobacterial biomass, (II) cell debris (pellet) after centrifugation of complex biomass, (III) supernatant after centrifugation of complex biomass (= crude aqueous extract), (IV) permeate after passing of crude extract through C-18 column (fraction devoid of microcystins), and (V) eluate from C-18 column (containing microcystins, if present). Besides classical parameters evaluated in 96 h FETAX (mortality, growth inhibition, malformations), we have also assessed the effects on biochemical markers of oxidative stress and detoxification (glutathione pool, GSH; activity of glutathione peroxidase, GPx; glutathione reductase, GR; activity of glutathione-S-transferase, GST). Complex biomass (I) and aqueous extract (III) were generally the most toxic fractions in terms of mortality and growth inhibition, whereas eluates containing microcystins (V) were generally less toxic. On the other hand, the same fraction (eluates) induced significant malformations in low concentrations but the effects were not related to the content of microcystins. Biomarkers were affected in variable manner but no significant effect or clear relation to microcystin content was observed. Our data support the hypothesis that microcystins are not the only or major toxic compounds in the complex cyanobacterial samples (at least for some species) and that more attention should be paid to other components of complex cyanobacterial biomass including non-specific parameters such as oxygen content or toxic ammonia released during bacterial decay of organic material.

Toxicity and modulations of biomarkers in Xenopus laevis embryos exposed to polycyclic aromatic hydrocarbons and their N-heterocyclic derivatives

Effects of a newly identified group of organic environmental pollutants of concern (N-heterocyclic derivatives of polycyclic aromatic hydrocarbons, NPAHs) were investigated using the 96 h FETAX (Frog Embryo Teratogenesis Assay - Xenopus). Beside standard FETAX parameters (mortality, malformations), changes in several biochemical markers were studied as early signs of intoxication. Biomarkers included determination of glutathione (GSH) levels and lipid peroxidation as well as activities of important detoxification and antioxidant enzymes (glutathione-S-transferase, glutathione peroxidase, glutathione reductase). 1,10-Phenathroline was the most toxic of all tested compounds (96 h LC(50) = 4 microM). All tested NPAHs induced malformations in the frog embryos. The data suggest that the exposure to NPAHs can induce oxidative stress in amphibians; most biochemical markers were modulated at concentrations lower than those resulting in significant mortality. Results document mortality and teratogenicity of all studied NPAHs to amphibian embryos while no significant mortality, teratogenicity or modulations in biochemical markers could be observed with unsubstituted polycyclic aromatic hydrocarbons (PAHs) at concentrations up to their water solubility. This information along with the significantly greater solubility and thus bioavailability compared to their nonsubstituted parent compounds suggests that NPAHs could contribute significantly to the overall aquatic toxicity of mixtures of PAHs and their derivatives.

Toxic effects and oxidative stress in higher plants exposed to polycyclic aromatic hydrocarbons and their N-heterocyclic derivatives

N-heterocyclic derivatives of polycyclic aromatic hydrocarbons (NPAHs) are widespread concomitantly with their parent analogues and have been detected in air, water, sediments, and soil. Although they were shown to be highly toxic to some organisms, our understanding of their occurrence, environmental fate, biological metabolism, and effects is limited. This study evaluated toxic effects of three homocyclic aromatic hydrocarbons (PAHs-phenanthrene, anthracene, fluorene) and their seven N-heterocyclic derivates on higher terrestrial plants Sinapis alba, Triticum aestivum, and Phaseolus vulgaris. Germinability, morphological endpoints, parameters of detoxification, and antioxidant components of plant metabolism as well as lipid peroxidation were studied in acute phytotoxicity tests. Phytotoxicity of NPAHs was generally more pronounced than the effects of parent PAHs, and it significantly differed with respect to the structure of individual NPAHs. Sinapis alba and T. aestivum were more sensitive plant species than P. vulgaris. Chemicals with the strongest inhibition effect on germination and growth of plants were phenanthridine, acridine, benzo[h]quinoline, and 1,10- and 1,7-phenanthroline. All tested chemicals significantly induced activities of detoxification and antioxidant enzymes (glutathione reductase, glutathione peroxidase, and glutathione-S-transferase) at nanomolar to low micromolar concentrations. Levels of reduced glutathione were induced by all tested chemicals except 1,10- and 4,7-phenanthroline. Furthermore, fluorene, carbazole, acridine, phenanthrene, phenanthridine, benzo[h]quinoline, and 1,7-phenanthroline significantly increased lipid peroxidation. The results of our study newly demonstrate significant toxicity of NPAHs to plants and demonstrate suitability of multiple biomarker assessment to characterize mechanisms of oxidative stress and to serve as an early warning of phytotoxicity in vivo.

Quaternary benzo[c]phenathridine alkaloids sanguinarine and chelerythrine do not affect transcriptional activity of aryl hydrocarbon receptor: Analyses in rat hepatoma cell line H4IIE.luc

Quaternary benzo[c]phenanthridine alkaloids (QBAs) sanguinarine and chelerythrine exert a plethora of biological activities. Nevertheless, the specific cellular target for these alkaloids within the cell was not identified as far. Several literary data indicate that biological effects of QBAs could be associated with aryl hydrocarbon receptor (AhR) signaling pathway, including cytochrome P450 CYP1A, however, available information are controversial. In this work we analyzed the effects of sanguinarine and chelerythrine on AhR activity in rat hepatoma cells HII4E.luc stably transfected with dioxin responsive element fused to luciferase gene (DRE-LUC). Studied QBAs were tested in submicromolar concentration range (0.0001-1 microM) and in incubation times 6, 24 and 48 h. Transcriptional activity of AhR was monitored by chemiluminiscence measurement of luciferase catalytic activity. Sanguinarine and chelerythrine did not activated AhR in any time or dose tested. Chelerythrine (1 microM) but not sanguinarine caused moderate inhibition of AhR activation by 10 picomolar dioxin (exponential phase of receptor activation). In contrast, AhR activation by 2.5 nM dioxin (saturated receptor) was not affected by either alkaloid tested. In conclusion, the findings presented here favor rather for inactivity or modest inhibitory effect of QBAs on AhR signaling pathways in vitro than for the activation of the receptor. Regarding the concentrations of QBAs occurring in vivo, the use of products containing sanguinarine and/or chelerythrine has low toxicological potential in terms of the interactions with AhR signaling pathways.

Separation of microcystins by capillary electrochromatography in monolithic columns

Contribution on microcystin variant analysis by capillary electrochromatography (CEC) with easily affordable spectrophotometric detection is presented. Two types of reversed-phase capillary columns formed by inorganic or organic polymer monoliths were prepared for this purpose. The analyses were performed isocratically by means of tris(hydroxymethyl) aminomethane (TRIS) buffers of mildly alkaline pH containing 30% (v/v) acetonitrile as the mobile phases. The samples were injected electrokinetically and the analyses were done at the same separation field strength of 500 V/cm. Microcystins were detected at 238 nm. Although both column types differ not only in monolith quality (inorganic versus organic) but also in the length of the aliphatic moiety (C8 versus C12) similar results were achieved. The on-column preconcentration as the encouraging prospect of electrochromatographic technique was also tested. Consequently 5% of column volume was injected in contrast with 0.5% at standard injection scheme resulting in the six times enrichment of the low concentrated cyanobacterial extract at the top of the separation column. From these preliminary results can be seen that the CEC method is fully applicable for rapid microcystin screening.

Effects of N-heterocyclic polyaromatic hydrocarbons on survival, reproduction, and biochemical parameters in Daphnia magna

N-heterocyclic polycyclic aromatic hydrocarbons (N-PAHs) belong among newly identified classes of environmental pollutants with relatively high toxic potential. N-PAHs have been detected in air, soil, marine environments, and freshwater sediments. The N-PAHs are present at lower concentrations than their nonsubstituted analogues but their greater solubility would lead to greater bioavailibity and potential for toxic effects. Here we present results of acute and chronic toxicity in traditional aquatic invertebrate ecotoxicological model (Daphnia magna) along with assessment of biochemical responses. Studied biomarkers in D. magna exposed to N-heterocyclic derivatives included glutathione levels and activities of detoxication and antioxidative enzymes glutathione S-transferase and glutathione peroxidase. Phenanthrene and 1,10-phenathroline were the most toxic of all tested compounds (EC50 < 6 microM after 48 h exposure) and all tested N-PAHs suppressed reproduction of Daphnia magna. The data suggest that N-PAHs can induce oxidative stress in D. magna. The significant decline of glutathione content was found in animals treated with acridine, 1,10-phenanthroline, benzo(h)quinoline, phenantridine, and phenazine. Significant decrease of GPx activities relative to controls was found for all tested compounds except of phenanthrene and phenazine. Activities of GST increased after exposure to phenanthridine, phenazine, and benzo(h)quinoline, and declined in D. magna treated with phenanthrene (significant at one concentration) or anthracene (not significant). Our results confirmed significant acute as well as chronic toxicities of N-PAHs as well as potential of biochemical parameters to be used as early warning signals of toxicity in Daphnia magna.

Alteration of steroidogenesis in H295R cells by organic sediment contaminants and relationships to other endocrine disrupting effects

A novel bioassay with the human adrenocortical carcinoma cell line H295R can be used to screen for endocrine disrupting chemicals that affect the expression of genes important in steroidogenesis. This assay was employed to study the effects of organic contaminants associated with the freshwater pond sediments collected in the Ostrava-Karvina region, Czech Republic. The modulation of ten major genes involved in the synthesis of steroid hormones (CYP11A, CYP11B2, CYP17, CYP19, 17betaHSD1, 17betaHSD4, CYP21, 3betaHSD2, HMGR, StAR) after exposure of H295R cells to sediment extracts was investigated using quantitative real-time polymerase chain reaction (PCR). Crude sediment extracts, containing high concentrations of polycyclic aromatic hydrocarbons (PAHs) and moderate amounts of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) significantly stimulated expression of the CYP11B2 gene (up to 10-fold induction), and suppressed expression of 3betaHSD2 and CYP21 genes. A similar pattern was observed with the extracts after treatment with concentrated sulfuric acid to remove labile chemicals (including PAHs) leaving only persistent PCBs, OCPs and potentially PCDD/Fs. Comparison of the results with other mechanistically based bioassays (arylhydrocarbon receptor, AhR, mediated responses in H4IIE-luc cells, and estrogen receptor mediated effects in MVLN cells) revealed significant endocrine disrupting potencies of organic contaminants present in the sediments (most likely antiestrogenicity). Pronounced effects were observed particularly in sediment extracts from the Pilnok Pond which harbors an unusual intersexual population of the narrow-cawed crayfish Pontastacus leptodactylus (Decapoda, Crustacea). This pilot study provided the first experimental evidence of the wider application of the H295R bioassay for screening complex environmental samples, and the results support the hypothesis of chemical-induced endocrine disruption in intersexual crayfish.

Evaluation of extraction approaches linked to ELISA and HPLC for analyses of microcystin-LR, -RR and -YR in freshwater sediments with different organic material contents

The efficiencies of conventional extraction techniques and analytical methods (HPLC-DAD and ELISA) were investigated for analyses of microcystins (MCs) in sediments. Our results showed several limitations. First, the extraction efficiency strongly depends on the extraction solvent, and extraction with 5% acetic acid in 0.2% trifluoroacetic acid (TFA)-methanol was confirmed as being the most appropriate for three different sediments (recovery: 33.1-44.9% of total MCs according to HPLC analyses). Second, the recovery of MCs was affected by the type of sediment but did not clearly correlate with the content of organic carbon. These results suggest that the sorption of MCs onto inorganic materials such as clay minerals is probably a more important process than interactions of the MCs with organic sediment matter. Third, the structure of the MCs is another crucial factor that affects the sorption of MCs and their recovery from sediments. Hydrophilic MC-RR gave much lower recoveries (20.0-38.8%) than MC-YR (44.1-59.5%) or MC-LR (55.3-77.8%) from three different types of spiked sediments. Recovery results analysed with HPLC-DAD correlated well with ELISA analyses. Further, extraction with 5% acetic acid in 0.2% TFA-methanol was used for analyses of MCs in 34 natural sediment samples collected from Brno reservoir (Czech Republic) from April to October 2005. Concentrations of MCs in sediments ranged from 0.003 to 0.380 microg/g sediment d.m. (ELISA results) or 0.016-0.474 microg/g d.m. (HPLC results). These values are equivalent to 0.63-96.47 microg/L of sediment (ELISA) or 4.67-108.68 microg/L (HPLC), respectively. Concentrations of sediment MCs showed both temporal and spatial variability, with the highest MC contents observed in the spring (April and May) and the lowest concentrations in July and August. Our results demonstrate the suitability of the methods described here for studying the occurrence, fate and ecological role of MCs in the aquatic environment.

Age dependency and mutual relations in T and B lymphocyte abnormalities in common variable immunodeficiency patients

Common variable immunodeficiency (CVID) is primary hypogammaglobulinaemia with an unknown aetiopathogenesis. Although various abnormalities of T and B cells have been described, their pathogenetic roles are unclear. We determined T and B lymphocyte subsets known to be abnormal in CVID in order to disclose possible relations between numerical abnormalities in those cells. Markers associated with B cell development (CD21, CD27, IgM, IgD) were determined on B lymphocytes (CD19+); T lymphocyte development (CD45RA, CD45RO, CD62L) and activation markers (CD25, CD27, CD28, CD29, CD38, CD57, HLA-DR) were determined on CD4+ and CD8+ T lymphocytes in 42 CVID patients and in 33 healthy controls. Abnormalities in CD4+ T lymphocyte activation markers (increase in CD29, HLA-DR, CD45RO, decrease in CD27, CD62L, CD45RA) were observed particularly in patients with a decreased number of memory (CD27+) and mature (CD21+) B cells (group Ia according to the Freiburg group's classification), while abnormalities observed in CD8+ cells (increase in CD27 and CD28 and decrease in HLA-DR, CD57 and CD38) did not depend upon grouping patients together according to B lymphocyte developmental subpopulations. We observed correlations between immature B cells (IgM+ CD21-) and expression of CD27, CD62L, CD45RA, CD45RO and HLA-DR on CD4+ T cells in CVID patients but not in the control group. The expression of CD27 and CD45RA on CD4+ T lymphocytes, such as the percentage of IgD+ CD27- and IgD+ CD27+ cells in B lymphocytes, showed age dependency to be more significant than in the control group. Our study demonstrates that T and B lymphocyte abnormalities in CVID are partially related to each other. Some of those abnormalities are not definite, but may evolve with age of the patient.

Activation of the aryl hydrocarbon receptor by berberine in HepG2 and H4IIE cells: Biphasic effect on CYP1A1

Berberine has long been considered a candidate for an antimalarial drug. It exerts a plethora of biological activities and has been used in the treatment of diarrhea and gastro-enteritis for centuries. Here we provide evidence that berberine activates the aryl hydrocarbon receptor (AhR) in human hepatoma (HepG2) and rat hepatoma cells stably transfected with a dioxin responsive element fused to the luciferase gene (H4IIE.luc). AhR was activated by high doses of berberine (10-50 microM) after 6 and 24 h of incubation as revealed by CYP1A1 mRNA expression (HepG2) and AhR-dependent luciferase activity (H4IIE.luc). Berberine induced nuclear translocation of AhR-GFP chimera transiently transfected to Hepa1c1c7 cells. In contrast, low doses of berberine (<1 microM) and prolonged times of the treatments (48 h) failed to produce any activation of AhR in H4IIE.luc cell line. HPLC analysis ruled out the hypothesis that the loss of berberine capacity to activate AhR in H4IIE.luc cells is due to metabolic inactivation of the alkaloid. We demonstrate that berberine is a potent inhibitor (IC50=2.5 microM) of CYP1A1 catalytic activity (EROD) in HepG2 cell culture and in recombinant CYP1A1 protein. Collectively, our results imply that while berberine activates the Ah receptor, it is accompanied by inactivation of the catalytic activity of CYP1A1 and occurs at concentrations that exceed those predicted to occur in vivo. Given these data, it appears that activation of the AhR pathway by berberine has a low toxicological potential.

Environmental xenobiotics and nuclear receptors--interactions, effects and in vitro assessment

A group of intracellular nuclear receptors is a protein superfamily including arylhydrocarbon AhR, estrogen ER, androgen AR, thyroid TR and retinoid receptors RAR/RXR as well as molecules with unknown function known as orphan receptors. These proteins play an important role in a wide range of physiological as well as toxicological processes acting as transcription factors (ligand-dependent signalling macromolecules modulating expression of various genes in a positive or negative manner). A large number of environmental pollutants and other xenobiotics negatively affect signaling pathways, in which nuclear receptors are involved, and these modulations were related to important in vivo toxic effects such as immunosuppression, carcinogenesis, reproduction or developmental toxicity, and embryotoxicity. Presented review summarizes current knowledge on major nuclear receptors (AhR, ER, AR, RAR/RXR, TR) and their relationship to known in vivo toxic effects. Special attention is focused on priority organic environmental contaminants and experimental approaches for determination and studies of specific toxicity mechanisms.

Toxicity of hydroxylated and quinoid PCB metabolites: inhibition of gap junctional intercellular communication and activation of aryl hydrocarbon and estrogen receptors in hepatic and mammary cells

In the present study, a series of 32 hydroxy- and dihydroxy-polychlorinated biphenyls (OH-PCBs) and PCB-derived quinones were prepared and evaluated for their in vitro potencies to downregulate gap junctional intercellular communication (GJIC) and to activate the aryl hydrocarbon receptor (AhR) and the estrogen receptor alpha (ER) in well-established liver and mammary cell models. The rat liver epithelial cell line WB-F344 was used for in vitro determination of GJIC inhibition; the AhR-inducing activity was determined in the rat hepatoma H4IIE.Luc cells stably transfected with a luciferase reporter gene; ER-mediated activity was measured in two breast carcinoma cell lines, MVLN and T47D.Luc, stably transfected with luciferase under the control of estrogen responsive element. Acute inhibition of GJIC, potentially associated with tumor promotion, was detected after treatment with all OH-PCBs under study, with the persistent OH-PCBs being the strongest ones. Several compounds were found to significantly induce the AhR-mediated activity, including 4'-OH-PCB 79, a metabolite of PCB 77, and 2-(4'-chloro)- and 2-(3',4'-dichloro)-1,4-benzoquinones and 1,4-hydroquinones. Low molecular weight OH-PCBs, such as 3'-hydroxy, 4'-, and 3',4'-dihydroxy-4-chlorobiphenyl, elicited significant estrogenic activity and potentiated effect of 17beta-estradiol. Antiestrogenic potencies, determined in the presence of 17beta-estradiol, were found for persistent 4-OH-PCB 187, 4-OH-PCB 146, and some low chlorinated PCB derivatives. However, no apparent association between induction of AhR activity and antiestrogenicity was observed. The majority of the OH-PCBs suppressed the 17beta-estradiol response only at cytotoxic concentrations. Spearman's rank correlations were calculated for these biological data and the physicochemical descriptors, hydrophobicity (log P), molar volume, pKa, log D, and dihedral angle. Significant correlations were found between potency to downregulate GJIC and log P and molar volume (R = -0.7, p < 0.0001). Antiestrogenic effects were also negatively correlated with hydrophobicity and molar volume. No significant correlations among other biological end points and the physicochemical descriptors were observed for the entire set of compounds. These results show that oxygenated PCB metabolites are capable of multiple adverse effects, including gap junction inhibition, AhR-mediated activity, and (anti)estrogenicity. The inhibition of GJIC by OH-PCBs represents a novel mode of action of both the lower chlorinated and the persisting high molecular weight OH-PCBs.

Induction of aryl hydrocarbon receptor-mediated and estrogen receptor-mediated activities, and modulation of cell proliferation by dinaphthofurans

A group of heterocyclic aromatic compounds, dinaphthofurans (DNFs), recently have been identified as potentially significant contaminants in freshwater sediments. In the present study, a battery of in vitro assays was used for detection of toxic effects of DNFs that are potentially associated with endocrine disruption and tumor promotion. Dinaphthofurans were found to act as relatively potent inducers of aryl hydrocarbon receptor (AhR)-mediated activity in the chemical-activated luciferase reporter gene expression DR-CALUX assay. The relative AhR-inducing potencies of DNFs were similar or even higher than relative potencies of unsubstituted polycyclic aromatic hydrocarbons (PAHs), with dinaphtho[1,2-b;2'3'-d]furan being the most potent AhR agonist. Two compounds, dinaphtho[2,1-b;2'3'-d]furan and dinaphtho[1,2-b;1'2'-d]furan, induced estrogen receptor (ER)-mediated activity in the estrogen receptor-mediated CALUX (the ER-CALUX) assay. Two types of potential tumor-promoting effects of DNFs were investigated, using in vitro bioassays for detection of inhibition of gap-junctional intercellular communication and detection of a release from contact inhibition. Although the acute inhibition of gap-junctional intercellular communication was not observed, all six tested DNFs were able to release rat liver epithelial WB-F344 cells from contact inhibition at concentrations as low as 100 nM. In summary, the present study indicated that DNFs can exert multiple biological effects in vitro, including induction of the AhR-mediated activity, release of cells from contact inhibition, and induction of ER-mediated activity.

Comparison of 17 biotests for detection of cyanobacterial toxicity

The aim of the present study was to compare the sensitivity of 17 acute bioassays of cyanobacterial toxicity by assessment of crude extracts of three cyanobacterial samples (all dominated by Microcystis sp. but substantially differing in microcystin-LR content). Toxicity of the fractions prepared by solid-phase extraction (SPE) for microcystins was also determined. The most sensitive bioassay was the 24-h test with crustacean Thamnocephalus platyurus, which elicited high lethality in the samples and also in fractions without microcystins. The fruit fly Drosophila melanogaster, protozoans Spirostomum ambiguum and Tetrahymena termophyla, and the crustacean Daphnia pulex formed the second group of sensitive bioassays. Good selective toxicity response to microcystins also was observed in the weakly sensitive biotests with the oligochaete Tubifex tubifex and the rotifer Brachionus calyciflorus. Preconcentration of microcystins by SPE substantially decreased variation of the results in bioassays and improved the discriminating potential of most assays employed.

Toxicity increases in ice containing monochlorophenols upon photolysis: environmental consequences

The toxic effects of photoproducts formed upon the photolysis of 2- and 4-chlorophenol (CP) frozen solutions in polycrystalline ice phase were determined with a bacterial luminescence test (Vibrio fisheri), and in vitro biomarker assay for dioxin-like effects (inductions of AhR-dependent luciferase in H4IIE-luc cells) and compared to the toxic effects of products of the same photoreaction in aquatic phase. Coupling photoproducts formed in ice samples (3'-chlorobiphenyl-2,4'-diol and 3-chlorobiphenyl-2,2'-diol from 2-CP photolysis and 5-chlorobiphenyl-2,4'-diol from 4-CP photolysis) were found to be more toxic to V. fisheri than parent CPs and elicited significant inductions of dioxin-like effects (the effective concentrations EC50 approximately 3 x 10(-5) mol L(-1) corresponded to known weaker ligands of AhR, such as nonplanar polychlorinated biphenyls or polycyclic aromatic hydrocarbons). To complete the picture, a photoproduct formed from 4-CP (5-chlorobiphenyl-2,4'-diol) was synthesized, and a detailed toxicity assessment with purified compound confirmed the results obtained with irradiated samples. Our findings support a recently proposed model according to which solar radiation can trigger the formation of new types of organic pollutants in polar ice or tropospheric ice cloud particles, presenting possibly greater risk to the environment than the parent compounds.

Geosmin occurrence in riverine cyanobacterial mats: is it causing a significant health hazard?

Toxicity endpoints (nonspecific cytotoxicity, hepatotoxicity, neurotoxicity, immunotoxicity, and mutagenicity) were studied in cyanobacterial mats obtained from a shallow river. Some of the cyanobacterial mats tested were known to be non-geosmin producers, while others were geosmin-producers. No microcystin-like compounds were detected by HPLC in any of the biofilm samples. The mutagenicity and neurotoxicity of biofilm metabolites was negligible, and generally weak adverse effects of biofilm extracts detected in a battery of in-vitro assays indicated relatively low human health risks associated with biofilm toxicity. While the toxicity responses detected in the studied biofilms were weak, effects were not related to production of geosmin. It was therefore concluded that the production of this metabolite cannot be taken as an indication per se of the existence of a health hazard.

Inhibition of gap junctional intercellular communication by noncoplanar polychlorinated biphenyls: inhibitory potencies and screening for potential mode(s) of action

Polychlorinated biphenyls (PCBs), a structurally diverse group of environmental pollutants, are effective promoters in two-stage cancer models, which implies that epigenetic mechanisms are involved. Inhibition of gap junctional intercellular communication (GJIC) belongs among critical epigenetic events of tumor promotion. We determined the relative potencies of a series of environmentally relevant PCB congeners to inhibit GJIC in vitro in a rat liver epithelial cell line with pluripotent oval cell characteristics. The nonplanar PCBs were potent inhibitors of GJIC, whereas the coplanar PCBs did not inhibit GJIC. We then compared the effects of the coplanar PCB 126 (3,3',4,4',5-pentachlorobiphenyl) and the noncoplanar PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl) with effects of two model GJIC inhibitors, a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF). In contrast to TPA or EGF, PCB 153 elicited a long-term downregulation of GJIC (up to 48 h). Using Western blot analysis with phospho-specific antibodies, it was found that PCB 153, and not PCB 126, activated mitogen-activated protein kinases ERK1/2; however in contrast to TPA and EGF, this activation was observed at the time points subsequent to GJIC inhibition. Moreover, blocking of ERK1/2 activation did not prevent the GJIC inhibition induced by PCB 153. Therefore, additional intracellular signaling pathways potentially involved in the downregulation of GJIC by PCBs were screened by using specific chemical probes inhibiting serine/threonine kinases, tyrosine kinases, and phospholipases. The inhibition of diacylglycerol lipase partially blocked and the selective inhibition of Src kinases and phosphatidylcholine-specific phospholipase C (PC-PLC) completely blocked the inhibitory effects of the noncoplanar PCB on GJIC, indicating that PC-PLC or sphingomyelinase and Src might be upstream regulators of noncoplanar PCB-induced inhibition of GJIC.

Effects of cyanobacterial biomass and purified microcystins on malformations in Xenopus laevis: teratogenesis assay (FETAX)

Xenopus laevis (African clawed frog) embryos in a 96-h teratogenesis assay (FETAX) were exposed to 0-250 microg/L and 500 microg/L of purified microcystin-LR (MCYST-LR) for the estimation of lethality, as well as to equivalent concentrations of biomass containing MCYST-LR (natural water bloom dominated by Microcystis aeruginosa) and biomass without MCYST-LR (bloom dominated by Microcystis wesenbergii). The highest tested concentrations of purified MCYST-LR caused up to 30% lethality after a 96-h exposure, corresponding to a LC(25) of 380 microg/L. Cyanobacterial biomass containing MCYST-LR caused significant lethality up to 50% at the highest tested concentrations (300 mg/L, i.e., 250 microg/L of MCYST-LR). The estimated 96-h LC(25) values varied from 125 mg/L (biomass containing MCYST-LR) up to 232 mg/L (biomass without MCYST-LR). A statistically significant increase in the number of malformed embryos was observed after exposure to cyanobacterial samples. Purified MCYST-LR at and above 25 microg/L significantly increased the number of malformations, with 53% of surviving embryos malformed in the highest tested concentration, 250 microg/L (EC(25) = 27 microg/L). Exposure to the highest concentration of MCYST-LR containing biomass resulted in more than 60% of the embryos being malformed and an EC(25) of 52 mg/L (i.e., 43 microg of MCYST-LR/L). Cyanobacterial biomass with no natural microcystin also induced substantial malformations-about 50% aberrant embryos at the highest concentration, 300 mg/L (EC(25) = 75 mg/L). External additions of purified MCYST-LR to the biomass that was originally without microcystins resulted in a slight additional increase in the rate of malformations (80% at the highest concentration, 300 mg of biomass plus 250 microg of MCYST-LR per liter). A comparison of lethality and effects on malformations (teratogenic index, TI = LC(25)/EC(25)) showed that all samples had significant teratogenic potential in the FETAX assay (TI(MCYST-LR) = 14; TI for biomass with and without microcystin ranged between 2.4 and 3.1, respectively). We conclude that cyanobacterial water blooms can significantly alter the normal development of amphibian embryos.