[Vibrio infections from food and sea water. Introducing the "VibrioNet"]. / Vibrio-Infektionen durch Lebensmittel und Meerwasser. Das Netzwerk "VibrioNet" stellt sich vor.

Vibrio is a genus of bacteria present in surface and coastal waters as well as in marine organisms worldwide. In many countries, pathogenic Vibrio species are a main cause of bacterial diarrhea, which may result from comsumption of contaminated seafood and fish products or from drinking contaminated water. Vibrio infections may also gain in importance in our regions due to global warming and the increase in the world trade of seafood. The research network "VibrioNet" studies pathogenic Vibrios in the marine environment and in seafood consumed by humans as a potential, new emerging zoonotic agent. An assessment of the risk arising from pathogenic non-cholera-vibrios in central Europe is the target of a multidisciplinary research effort. The research network will be strengthened by cooperations with international partners from countries in which Vibrio infections play a major role (Bangladesh, Chile, India, Thailand, and Vietnam).

Leukemia in the proximity of a German boiling-water nuclear reactor: evidence of population exposure by chromosome studies and environmental radioactivity.

Exceptional elevation of children's leukemia appearing 5 years after the 1983 startup of the Krümmel nuclear power plant, accompanied by a significant increase of adult leukemia cases, led to investigations of radiation exposures of the population living near the plant. The rate of dicentric chromosomes in peripheral lymphocytes of seven parents of children with leukemia and in 14 other inhabitants near the plant was significantly elevated and indicated ongoing exposures over the years of its operation. These findings led to the hypothesis that chronic reactor leakages had occurred. This assumption is support by identification of artificial radioactivity in air, rainwater, soil and vegetation by the environmental monitoring program at the nuclear power plant. Calculations of the corresponding source terms show that emissions must have been well above authorized annual limits. Bone marrow doses supposedly result primarily through incorporation of bone-seeking beta- and alpha-emitters.

Whole library-amplification and labelling of human chromosome-specific composite probes for fluorescence in situ hybridization (FISH) using PCR.

Chromosome painting with human-specific, whole-plasmid library probes has become a widespread technique in cytogenetic research and radiation biology. Fast and convenient methods for probe amplification and labelling are required that conserve the complexity of the libraries and stain the entire length of selected chromosomes. The present study uses PCR for amplification and labelling of the whole bluescribe plasmid libraries pBS1, pBS4 and pBS12 using M13 forward and reverse sequencing primer. Amplification and labelling can be accomplished within a few hours with a minimum of laboratory equipment and costs. It is therefore suitable for all laboratories that do not have the facilities for growing transformed bacteria containing plasmids with inserts of human origin.

The chromosome-based challenge assay using fluorescence in situ hybridization: a possible test for increased cancer susceptibility.

UNLABELLED: The challenge assay is a cytogenetic approach to measure the repair competence of cells. For in vitro studies, human lymphocytes are exposed to different substances and are irradiated simultaneously. To investigate subjects exposed occupationally or environmentally, untreated blood samples are directly irradiated without any further treatment. Certain substances like heavy metals reveal carcinogenic potential without well defined mechanism of action. While they are not mutagenic they may have an effect on DNA repair capacity. The challenge assay was successfully applied in vitro experiments with cadmium to detect an interaction of this heavy metal with the repair of X-ray-induced chromosome breaks. CdCl(2) alone had no effect on the formation of chromosome aberrations (CA), not even in the cytotoxic concentration (50 microM). However, cadmium showed an effect on the number of chromosomal rearrangements (CR) after X-ray challenge. For 0.5 microM CdCl(2), CA frequencies were significantly elevated compared to the rates for X-rays alone. For the two higher concentrations the rates showed a slight additional increase. Hence, the challenge assay appears suitable to test for chromosomal sensitivity induced by toxicants. Subsequently, a study of styrene exposed workers was initiated to address the question whether styrene exposure has an influence on the DNA repair. In addition, we investigated whether a polymorphism of genes coding for phase II detoxifying enzymes glutathione-S-transferases GSTM1 and GSTT1 had an influence on chromosomal sensitivity. First and preliminary data are presented. While there is a correlation of the rate of CR with cumulative lifetime exposure of styrene, the most recent styrene exposure had no effect. 'At risk' genotypes with higher incidence of CA could not be identified at this stage of the ongoing study. CONCLUSION: the challenge assay is able to detect enhanced susceptibility for CR caused by genetic predisposition for DNA repair deficiency. Our data indicate that environmental or occupational exposure to certain substances can interfere with DNA repair processes. As the process of induction of CR is associated with carcinogenesis, the challenge assay may provide a valuable biomarker for cancer epidemiology studies.

Biomarker monitoring for health risk based on sensitivity to environmental mutagens.

Ongoing human and environmental genome programs have generated a tremendous amount of information regarding the genetic basis for human disease. The information can be used to enhance existing bioassays, as well as to develop new bioassays for improving human monitoring with the goal of disease prevention. In this review, some biomarkers that can be used for the purpose are presented, with an emphasis on using biomarkers to monitor human sensitivity to environmental mutagens. The application of biomarkers in clarifying the role of inherited and acquired susceptibility for developing environmental disease will be discussed. We emphasize the use of biomarkers that can detect mutagen sensitivity and DNA repair deficiency in the humans as an indication of susceptibility to disease. Such sensitivity can be either genetically determined or acquired from the exposure to environmental mutagens.

An application of the challenge assay in boat builders exposed to low levels of styrene--a feasibility study of a possible biomarker for acquired susceptibility.

Sensitivity to carcinogens and susceptibility for malignant diseases may be related to genetic predisposition, e.g. polymorphisms in toxicant-metabolizing enzymes or DNA repair deficiencies. The latter may also be acquired by exposure to substances that interfere with DNA repair processes. Application of the challenge assay to an exposed population may allow scientists to study the interference of DNA repair as an acquired susceptibility phenomenon. The assay was therefore used in a feasibility study to evaluate its application. A group of 14 workers exposed to low levels of styrene (mean < 100 mg/m3 styrene in air; 35 micrograms/l styrene in blood) and a reference of seven controls were investigated for structural chromosomal aberrations using FISH. The rate of exchange-type aberrations per 100 metaphases was 0.14 (95% CI, 0.05-0.31) in controls and 0.22 (95% CI, 0.13-0.36) in exposed workers. The difference is not statistically significant. Interaction with DNA repair was measured in the 14 workers and 2 historical controls using the challenge assay. Exchange-type aberrations per 100 metaphases after X-ray challenge of 1.66 Gy were 13.26 (10.53-16.50) and 16.19 (15.00-17.40) for the controls and exposed, respectively. The difference is statistically significant (p < 0.038). Among the exposed group, the challenge response was also significantly correlated with the cumulative lifetime exposure to styrene (R2 = 0.3996; p < 0.015) but not with the current exposure as measured in blood (R2 = 0.0226; p = 0.700). The challenge responses in the short-term and long-term exposed subgroups were 15.55 (14.23-16.96) and 17.90 (15.64-20.39), respectively, based on sample sizes of 5 and 9, respectively. The difference was not significant. Hence, data from our study are consistent with the hypothesis that long-term exposure to styrene can interfere with DNA repair activities. The lack of statistically significant differences in some of the data may be due to the small sample size and a possible confounding by age in our investigation. Additional data from our ongoing study should clarify this uncertainty.

"Host factors"--evolution of concepts of individual sensitivity and susceptibility.

The detection of a rapidly increasing number of genetic polymorphisms in xenogen-metabolizing enzymes, of hereditary as well as acquired individual differences in DNA repair, and of the close associations between central nervous structures, the endocrine, and the immune system provides a challenge to develop an evidence-based, comprehensive model of susceptibility. Reviewing the evolution of respective approaches from 400 B.C. until today, this article proposes a conceptional framework that integrates the diverse, and sometimes puzzling contributions from all different fields of life science.

Heat shock response and cytotoxicity in C6 rat glioma cells: structure-activity relationship of different alcohols.

In C6 rat glioma cells, the n-alcohols methanol, ethanol, propanol, and butanol and the aromatic alcohol phenol all induce heat shock proteins (HSPs) of high molecular mass (68, 70, 90, and 110 kDa) when applied for 1 hr. The lowest alcohol concentrations that induce HSP synthesis cause about 20% cell death, as determined by neutral red assay. HSP induction thus occurs at alcohol concentrations close to the highest tolerable dose. The cytotoxicity and the potential of alcohols to induce the synthesis of HSPs increase with chain length and are correlated with the lipophilicity of the alcohols. A clear structure-activity relationship is observed for both parameters. A calculation of the putative membrane concentrations of these alcohols reveals that cytotoxic effects (50% cell death) occur at nearly the same membrane concentration (approximately 0.2 M). This also holds true for the lowest HSP 68-inducing alcohol concentrations, but at a lower concentration (approximately 0.12 M). The activities of major proteinases are affected by both heat shock and alcohols. The effects of alcohols also depend on the lipophilicity of the alcohols. Effective concentrations again are close to the highest tolerable dose. The stress reactions measured in terms of significant changes in HSP synthesis and proteinase activity provide information about the mechanisms by which toxic agents act on the cell.