Avoiding the effect of BCG vaccination in detecting Mycobacterium tuberculosis infection with a blood test.

Bacille Calmette-Guérin (BCG) vaccination can confound tuberculin skin test (TST) reactions in the diagnosis of latent tuberculosis infection (LTBI). The TST was compared with a Mycobacterium tuberculosis (MTB)-specific enzyme-linked immunospot (ELISPOT) assay during an outbreak of MTB infection at a police academy in Germany. Participants were grouped according to their risk of LTBI in close (n = 36) or occasional (n = 333) contacts to the index case. For the TST, the positive response rate was 53% (19 out of 36) among close and 16% (52 out of 333) among occasional contacts. In total, 56 TST-positive contacts (56 out of 71 = 78.9%) and 27 TST-negative controls (27 out of 298 = 9.1%) underwent ELISPOT testing. The odds ratio (OR) of a positive test result across the two groups was 29.2 (95% confidence interval (CI) 3.5-245.0) for the ELISPOT and 19.7 (95% CI 2.0-190.2) for the TST with a 5 mm cut-off. Of 369 contacts, 158 (42.8%) had previously received BCG vaccination. The overall agreement between the TST and the ELISPOT was low, and positive TST reactions were confounded by BCG vaccination (OR 4.8 (95% CI 1.3-18.0)). In contrast, use of a 10-mm induration cut-off for the TST among occasional contacts showed strong agreement between TST and ELISPOT in nonvaccinated persons. In bacille Calmette-Guérin-vaccinated individuals, the Mycobacterium tuberculosis-specific enzyme-linked immunospot assay is a better indicator for the risk of latent tuberculosis infection than the tuberculin skin test.

Synthetic musks in the environment. Part 1: Species-dependent bioaccumulation of polycyclic and nitro musk fragrances in freshwater fish and mussels.

Bioaccumulation of polycyclic musks (HHCB, AHTN) and nitro musks (musk xylene, musk ketone, and their amino metabolites) in aquatic biota was investigated by analyzing 18 fish samples (rudd, tench, crucian carp, eel) and 1 pooled zebra mussel sample from the pond of a municipal sewage treatment plant. Furthermore, water samples taken at the effluent of the sewage plant as well as water samples and two series of semipermeable membrane devices (SPMDs) from the pond were included. This comprehensive data set allowed the determination of species-dependent bioaccumulation factors on a lipid basis (BAF(L)), e.g., for HHCB the BAF(L) in tench were more than 20 times higher than in eel. The BAF(L) for HHCB and AHTN in biota were lower than the partition coefficients K(SPMD/W) obtained from SPMD samples, which are assumed to represent model bioconcentration values. This stresses that metabolism of these compounds in fish must not be neglected.

Synthetic musks in the environment. Part 2: Enantioselective transformation of the polycyclic musk fragrances HHCB, AHTN, AHDI, and ATII in freshwater fish.

A method for the enantioselective separation of the chiral polycyclic musks HHCB, AHTN, AHDI, and ATII is presented. Eighteen fish samples (rudd, tench, crucian carp, eel) and one pooled zebra mussel sample from the pond of a municipal sewage treatment plant were investigated with regard to their concentrations and the enantiomeric ratios (ERs) of polycyclic musks. In addition, three water samples taken at the effluent of the sewage plant, as well as two water samples and two series of semipermeable membrane devices (SPMDs) consisting of six samples each from the pond were included in the present study. This comprehensive data set allowed a reliable evaluation of species-dependent metabolization processes. The pattern of the polycyclic musks in the chromatograms obtained by enantioselective gas chromatography seems to be typical of each species, like a fingerprint. The highest deviations from the racemic ER were found for trans-HHCB and trans-ATII in crucian carp with values of or below 0.1. Calculations showed that enantioselective transformation seems to be the most important process, resulting in the observed lower concentrations in crucian carp compared to tench. Consequences for a risk assessment are discussed.

In vitro suppression of thymocyte apoptosis by metal-rich complex environmental mixtures: potential role of zinc and cadmium excess.

Excessive amounts of heavy metals (e.g. Zn, Cu, Mn, Cr) are accumulated in river bottom sediments (RBS), being available to humans and animals along food chains. Increased exposure of mammals to certain metals (Cr, Cu) induces immunosuppresion, due to DNA damage and decreased survival of lymphoid cells. By contrast, excess of Zn and Cd causes inhibition of apoptosis thus suggesting increased survival of genetically mutated cells and higher cancer risks in exposed populations. Rat thymic lymphocytes represent a well-established model for apoptosis testing. The primary goal of our study was to assess the degree of apoptosis modulation with a number of RBS extracts differing in their metal contents. A series of freshly deposited RBS was collected at nine sampling stations along the Elbe River. All sediments were rich in Fe, Mn and Zn. The contents of Cu, Cr, Ni, Cd, Hg, Pb and As were much lower and interrelated. The short-term cytotoxicity of aqueous sediment extracts was assessed, using the following criteria: total cell counts; incidence of apoptosis and necrosis (morphological detection by fluorescent microscopy); and nuclear chromatin decay (by DNA flow cytometry). RBS extracts produced both apoptosis and necrosis of thymocytes. High contents of zinc and other heavy metals in the samples correlated with decreased thymocyte apoptosis (r= -0.543 to -0.608, P <0.01). The rates of thymocyte damage showed a distinct dependence on the time and region of sampling. Apoptosis modulation was also tested with pure salts of Mn(II), Zn(II), Cu(II), Cr(III) and Cd(II), at the test concentrations of 1, 10 and 100 microM. Cu(II) and Cr(III) proved to induce marked dose-related apoptosis, whereas Zn(II) ions caused significant suppression of apoptosis. These effects were similar to those trends observed with metal-rich sediments. In the present study. DNA flow cytometry proved to be a less sensitive index of cell death than morphological assay of apoptosis and/or necrosis. In summary, inhibition of lymphocyte apoptosis by RBS extracts and pure metals is associated with excess of zinc and, probably, cadmium. The proposed model of lymphoid cell apoptosis is a promising tool for screening cytotoxic effects of complex environmental samples.

Genotoxicity assessment of suspended particulate matter in the Elbe river: comparison of Salmonella microsome test, arabinose resistance test, and umu-test.

This study evaluates the applicability of three bacterial short-term genotoxicity test systems to aquatic suspended particulate matter of the Elbe river. This material was sampled in sedimentation vessels after deposition periods of one month. It was extracted in a Soxhlet apparatus with toluene and methanol. Aqueous elutriates were prepared additionally. A solid phase method was developed that enables to incubate bacteria in contact with the particulate material. The test battery consists of two mutagenicity assays (the Ames-test and the Ara-test) and an SOS induction assay (the umu-test). Both mutagenicity assays came to nearly the same assessment of the samples of particulate matter of the Elbe. The quantitative response, however, was higher in the Ara-test. The particulate river material generally induced lower genotoxic potencies in the umu-test than in the mutagenicity assays. This lead to a completely different outcome of the umu-test; 29 out of 35 mutagenic samples were not SOS inducing. No quantitative or rank correlations between the concentrations of anthropogenic contaminants (PAHs, chlorinated hydrocarbons and metals) and the observed effects could be established on a 90% confidence limit. However, there is obvious correspondence between more contaminated regions of the river system and mutagenic effects (Ames- and Ara-test) in the samples from this region, as well as correspondence between low contaminated regions and the absence of mutagenicity. For this reason, the mutagenicity assays appear more favourable to describe the anthropogenic contamination with genotoxins in complex mixtures than the umu-test. The authors recommend the Ara-test for a first genotoxicity screening of complex environmental mixtures. This forward mutagenicity assay is advantageous due to higher effects and lower costs compared to the Ames-test. The development and use of a solid phase version of Ames- and Ara-test revealed the occurrence of a major part of particle-bound mutagens. The hydrophobic nature of these mutagens was also confirmed by the gradually decreasing effects with decreasing lipophilicity of the solvents. The results suggest that the solid phase test and the use of extracts complement each other in detecting mutagens of different lipophilicity. Both versions should be used in order to include a broad variety of compounds.

Suitability of the ruffe (Gymnocephalus cernua [L.]) for investigations on activity of hepatic enzymes induced by xenobiotics.

Activity measurements of enzymes catalyzing (i) the oxidation of xenobiotics (phase I) and (ii) the conjugation of metabolites produced in phase I (phase II) were carried out in ruffe to test its suitability for biological monitoring. Ruffe typically lives in the lower regions of rivers and in estuaries where monitoring is of particular interest for estimating the amount of pollutants introduced into the sea. The flounder, already examined for this purpose, is used as reference organism. In ruffe, the enzymatic activity (7-ethoxycoumarin-O-deethylase (ECOD) and 7-ethoxyresorufin-O-deethylase (EROD)) increased with the contamination of the river toward Hamburg whereas in flounder it did not. The absence of a correlation between induction of the enzymatic activity in flounder and environmental contamination is attributed to the higher readiness of the flounder to migrate. Therefore, mixed function oxygenase activity found in flounders may not represent the inducing capacity of the local concentrations of xenobiotics. Since ECOD activity in ruffe was 5 to 20 times higher compared to the flounder, histopathological findings of investigations of the liver tissue were considered. Destruction or pathological changes of the endoplasmatic reticulum (where ECOD and EROD are located) is often reported in flounder but not in the ruffe, which may influence the expression of some enzymatic activities. The enzymatic activity of the phase II enzyme glutatione-S-transferase, which is considered to have a protective function in the cell against damages, caused by reactive metabolites, was more induced in ruffe than in flounder. Thus the ruffe may be less subjected to cell injury.

Biochemical responses and environmental contaminants in breams (Abramis brama L.) caught in the river Elbe.

Adult breams (Abrama brama L.) were caught in October 1992 at seven stations in the river Elbe and at one nonpolluted reference site, the Belauer See. The locations of the sampling stations extended from the city of Steti (Tschechien Republic) to the city of Hamburg. Indices of biochemical effects in microsomal and cytosolic fractions of livers were studied by measuring cytochrome P450-dependent monooxygenases and glutathione-S-transferase (GST) activities. In addition, levels of mercury and 35 polychlorinated biphenyl (PCB) congeners were analyzed in livers of breams. Fish caught in the River Elbe exhibited a significant increase of cytochrome P450-mediated monooxygenase activities and the detoxifications enzyme GST compared to the reference site. At two stations of the river Elbe (Steti and Dresden) elevated activities of ethoxyresorufin-O-deethylase (EROD) were analyzed. These effects were discussed as effects from the pulp mill industries at station Steti and high concentrations of PCBs in the livers of breams at station Dresden. A significant reduction of GST activities was observed at station Dresden compared to those at Steti. These findings were probably a synergistic effect of high mercury concentrations at Dresden. The results presented in this study suggest that breams can be successfully employed for monitoring biological effects in the river Elbe.

Induction of the hepatic biotransformation system of golden ide [Leuciscus idus (L.)] after exposure in the River Elbe.

The xenobiotic-metabolizing enzyme system of hatchery golden ide [Leuciscus idus (L.)] were tested for applicability in biological monitoring in rivers. The golden ide, cyprinid fish used for toxicity testing, were caged for 1 to 3 weeks in flowthrough systems at various locations of the river Elbe. The activities of 7-ethoxycoumarin-O-deethylase (ECOD) and the cytochrome P450 (P450) concentrations in the livers were analyzed. Exposure in the river Elbe increased the ECOD activity and the P450 concentration. In a flowthrough basin located in the harbor of Hamburg the ECOD activity increased up to 3.5 times, and the P450 concentration increased slightly by a factor of 1.5. During exposure of the golden ide at two Elbe stations upstream and downstream the city of Hamburg, levels of P450 in the livers did not change significantly when compared with laboratory controls. There was, however, a significant increase of ECOD activity between stations Bunthaus (upstream) and Blankenese (downstream). The ECOD activity in the livers of golden ide caged downstream were significantly higher compared to those at the upstream station. The results presented in this study suggest that golden ide can be employed as experimentals for routine measurements in limnic habitats using biochemical assays.