International Graduate College

"Molecular Mechanisms of Food Toxicology"

Sprecheruniversität:

Heinrich-Heine-Universität Düsseldorf
Universitätsstraße 1
D-40225 Düsseldorf

Tel.: +49 211 81-13022
Fax: +49 211 81-13013

 

EUROTOX Speciality Section Carcinogenesis „Diet and Cancer“  

held in Dortmund/Germany, May 16, 2003


1st International Conference "Molecular Research in Environmental Medicine"

Düsseldorf, March 18 - 20, 2004, Germany


12th EUROTOX Training and Discussion Session "Protective Agents in the Diet"

held in Dortmund/Germany, May 16, 2003


 


General description

Food safety is a major public and scientific concern. Food toxicology investigates the impact of natural and synthetic compounds present in food on human health, taking into account dangerous effects such as carcinogenicity, allergy, immunotoxicity and neurotoxicity on the one side and the potential for the prevention of disease on the other side. It is the aim of the European Graduate College ”Molecular mechanisms in food toxicology” to contribute to the understanding at a molecular level of pathways by which food compounds exert their toxic or preventive effects.  While there is a focus on molecular biological techniques to study signal transduction, gene expression and cell cycle control in most of the 10 projects, electrophysiological and analytical methods as well as  neurobehavioral testing are also  applied. The models used range from cell culture systems to perfused organs and intact animals. Thesis topics are divided into two sections: Section A concentrates on genotoxic and endocrine mechanisms in food toxicology while in section B the focus is on the protective effects of antioxidative food constituents. The expected research results can contribute to the setting of health-based standards and to the elaboration of preventive strategies for human health.

Students with a degree in either natural science or medicine can participate in the college. They are trained to conduct high-quality, specialized  research resulting in the completion of a doctoral thesis. A German and a Dutch supervisor jointly take care of each research project. Complementary techniques from their laboratories are provided to support progress of the thesis work. The students  work in both laboratories and  thus have the opportunity to practise the scientific and social requirements of cooperative research. The accompanying educational programme  covers a broad spectrum of toxicology, exceeding the highly specialized area of food toxicology in which the students conduct their research, teaching theoretical knowledge in all the central areas of toxicology and making students familiar with subjects of applied toxicology by involving teachers from regulatory agencies and industry. The curriculum is adapted to the requirement of national boards registering qualified toxicologists. We expect that the students when leaving the Graduate College will find jobs in a wide variety of toxicologically oriented  workplaces in academia, industry and administration.

.
German co-ordinator

        Prof.Dr.Regine Kahl
                Institute for Toxicology, Heinrich Heine University Düsseldorf
                Postfach 10 10 07, D-40001 Düsseldorf
                Phone +49/211-81 13013, Fax +49/211-8113013
                e-mail kahl@uni-duesseldorf.de

Dutch co-ordinator

        Prof.Dr.J.Kleinjans
                Department of Health Risk Analysis and Toxicology, University of Maastricht
                P.O.Box 616, 6200 MD Maastricht
                Phone +31/43-3881097, Fax +31/43-3670924
                e-mail j.kleinjans@grat.unimaas.nl

 
 

Participants in Germany

Research Institute for  Environmental  Medicine at the Heinrich Heine University  Düsseldorf
Auf´m Hennekamp 52, D-40225 Düsseldorf
Phone +49/211-3389 204, Fax +49/211-3190910
e-mail josef.abel@uni-duesseldorf.de

Prof.Dr.Dr.Hermann Bolt
        Institute for Occupational Physiology at the University Dortmund
        Ardeystr.67, 44139 Dortmund
        Phone +49/231-1084 348, Fax +49/231-1084 403
        e-mail bolt@arb-phys.uni-dortmund.de

Prof.Dr.Paul Borm
        Research Institute for  Environmental  Medicine at the Heinrich Heine University  Düsseldorf
        Auf´m Hennekamp 52, D-40225 Düsseldorf
        Phone +49/211-3389 269, Fax +49/211-3389 331
        e-mail paul.borm@uni-duesseldorf.de

Prof.Dr.Dr.Gisela Degen
        Institute for Occupational Physiology at the University Dortmund
        Ardeystr.67,  44139 Dortmund
        Phone+49/231-1084 351, Fax +49/231-1084 403
        e-mail degen@arb-phys.uni-dortmund.de

Prof.Dr.Ernst Gleichmann
        Research Institute for  Environmental  Medicine at the Heinrich Heine University Düsseldorf
        Auf´m Hennekamp 52, D-40225 Düsseldorf
        Phone +49/211-3389 244, Fax +49/211-3190910
        e-mail ernst.gleichmann@uni-duesseldorf.de

Prof.Dr.Regine Kahl
        Institute for Toxicology, Heinrich Heine University Düsseldorf
        Universitätsstr.1, D-40225 Düsseldorf
        Phone +49/211-81 13013, Fax +49/211-81 13013
        e-mail kahl@uni-duesseldorf.de

Prof. Dr. Helmut Sies
        Institute for Physiological Chemistry I,  Heinrich Heine University Düsseldorf
        Postfach 10 10 07, D-40001 Düsseldorf
        Phone +49/211-81 12707, Fax +49/211-81 13029
        e-mail: helmut.sies@uni-duesseldorf.de

Priv. Doz. Dr. Wilhelm Stahl
        Institute for Physiological Chemistry I,  Heinrich Heine University Düsseldorf
        Postfach 10 10 07, D-40001 Düsseldorf
        Phone +49/211-81 12711, Fax +49/211-81 13029
        e-mail: wilhelm.stahl@uni-duesseldorf.de

Prof.Dr.Herbert Wiegand
        Research Institute for  Environmental  Medicine at the Heinrich Heine University Düsseldorf
        Auf´m Hennekamp 52, D-40225 Düsseldorf
        Phone +49/211-3389 325, Fax +49/211-3389 331
        e-mail wiegand@uni-duesseldorf.de

Prof.Dr.Gerhard Winneke
        Research Institute for  Environmental  Medicine  at the Heinrich Heine University Düsseldorf
        Auf´m Hennekamp 52, D-40225 Düsseldorf
        Phone +49/211-3389 325, Fax +49/211-3389 ???
        e-mail gerhard.winneke@uni-duesseldorf.de

Prof.Dr.Frank Wunderlich
        Department for Molecular Parasitology, Heinrich Heine University
        Universitätsstr.1, D-40225 Düsseldorf
        Phone +49/211-81 13401, Fax +49/211-81 14734
        e-mail frank.wunderlich@uni-duesseldorf.de

 

Participants in The Netherlands

Dr.J.M.M.J.G.Aarts
        Department of  Toxicology, University of  Wageningen
        Tuinlaan 5, 6703 HE Wageningen
        Phone +31/ 317 4 84936, Fax +31/ 317 4 84931
        e-mail: jac.aarts@Algemeen.TOX.WAU.nl

Dr.Gerrit M. Alink
        Department of Toxicology, University of Wageningen
        Tuinlaan 5, 6703 HE Wageningen
        Phone +31/ 317-484294, Fax +31/
        e-mail gerrit.alink@Algemeen.TOX.WAU.nl

Prof. Dr.Aalt Bast
        Department of Pharmacology and Toxicology, University of Maastricht
        Postbus 616, NL-6200 MD Maastricht
        Phone: +31/43-3881418, Fax: +31/43-3884149
        e-mail A.Bast@farmaco.unimaas.nl

Prof.Dr.Johanna Fink-Gremmels
        Department of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Utrecht
        Yalelaan 16, NL-3508 TD Utrecht
        Phone +31/30-253 5453, Fax, +31/30-253 4125
        e-mail j.fink@vfft.vet.uu.nl

Prof.Dr.Jos Kleinjans
        Department of Health Risk Analysis and Toxicology, University of Maastricht
        P.O.Box 616, 6200 MD Maastricht
        Phone +31/43-3881097, Fax +31/43-3670924
        e-mail j.kleinjans@grat.unimaas.nl

Dr.Henk van Loveren
        Department of Immunobiology and Hematology, RIVM,
        Postbus 1, NL-3720 BA Bilthoven
        Phone: +31/30-274 2476, Fax: +31/30 274 4437
        e-mail h.van.loveren@rivm.nl

Prof.Dr.I.M.C.M.Rietjens
        Department of Toxicology, University of Wageningen
        Tuinlaan 5, NL-6703 HE Wageningen
        Phone +31/317 483723, Fax +31/317 484931
        e-mail ivonne.rietjens@p450.bc.WAU.nl

Dr.Hans Temmink
        Department of Toxicology, University of Wageningen
        Tuinlaan 5, NL-6703 HE Wageningen
        Phone +31/317-482656, Fax +31/317-484931
        e-mail hans.temmink@Algemeen.TOX.WAU.nl
 

6. Project description: Outline of the aims of the proposal, methods and workplan
 

Thesis topics and supervisors

 
Thesis topic    
German supervisor 
Dutch supervisor 
A1  
Influence of dietary factors like poly-unsaturated  
fatty acids and phytochemicals on colon cancer  
development: roles of PGHS-2 and PPARs 
Abel 
(Düsseldorf) 
Alink 
(Wageningen) 
A2  
Functional role of cytoskeletal proteins for  
chromosomal toxicity of phytoestrogens  
 
Bolt
(Dortmund) 
Kleinjans
(Maastricht)
A3  
Induction of DNA damage in human cells by  
ochratoxin A and other mycotoxins  
 
  Degen
(Dortmund) 
Fink-Gremmels
(Utrecht)
A4  
Interactions of dietary iodine deficiency with  
neonatal PCBs on thyroid function and brain  
development in rats 
Winneke
(Düsseldorf)
Kleinjans
(Maastricht)
A5  
Rapid non-genomic actions of testosterone:  
Intracellular signalling mechanisms and isolation  
of the plasma membrane receptor of testosterone 
Wunderlich
(Düsseldorf)
Rietjens
(Wageningen)
B1  
Pulmonary inflammation and systemic effects due to ambient particulates
 
 
Borm
(Düsseldorf) 
 Bast
(Maastricht)
B2  
Role of dietary flavonoids in the adaptation of  
antioxidant enzymes to prooxidants and pro-  
inflammatory mediators 
 Kahl
(Düsseldorf)
 Bast
(Maastricht)
B3  
Cooperative interactions of antioxidant  
micronutrients  
 
Sies, Stahl
(Düsseldorf)
Bast
(Maastricht)
B4  
Immunomodulation and altered gene expression  
induced by oral uptake of nickel (Ni) and zinc  
(Zn), respectively 
Gleichmann
(Düsseldorf) 
van Loveren
(Bilthoven)
B5  
Purinergic receptors of human macrophages:  
Influence of polychlorinated biphenyls and  
antioxidants on intracellular signal transduction  
and redox systems 
Wiegand; Borm
(Düsseldorf) 
Bast
(Maastricht)

 
 
 Short description of research projects
 

A1. Influence of dietary factors like poly-unsaturated fatty acids and phytochemicals on colon cancer development: roles of PGHS-2 and PPARs
        Abel (Düsseldorf) / Alink (Wageningen)

Colon cancer is a major cause of death in Western countries. This project studies mechanisms by which dietary factors can initiate and promote colon cancer development. Two lines will be followed: 1. Omega--3 polyunsaturated fatty acids (PUFAs) – assumed to be inhibitory to tumour development - and omega-6 PUFAs – assumed to promote tumour development - will be compared with respect to their influence on cell proliferation and apoptosis as well as on hydroxyl radical production and lipid peroxidation, taking into account the role of  dietary iron. 2. The enzyme prostaglandin H synthase-2 (PGHS-2) is involved in colon intestinal cell proliferation, differentiation and apoptosis. The effects of carcinogenic dietary heterocyclic amines on PGHS-2 expression and its consequences as well as the modulation of PGHS-2 expression by PUFAs and cancer-preventive phytochemicals will be investigated. The signal transduction mechanisms involved in PGHS-2 expression, e.g. the role of the transcription factor PPARg, will be clarified.
Added value of cooperation: Both laboratories already have PhD students working on the subject ”Prostaglandin H synthase-2 in relation to cancer development”. The methods used are largely complementary. The laboratory in Wageningen has expertise in animal experimental models for colon cancer development and in cell culture systems used to investigate gap junctional intercellular communication. The laboratory in Düsseldorf is specialised in the cultivation of primary cells, transfection experiments and molecular biological techniques like PCR, EMSA, and Western blotting.

A2. Functional role of cytoskeletal proteins for chromosomal toxicity of phytoestrogens
        Bolt (Dortmund) / Kleinjans (Maastricht)

Phytoestrogens are natural constituents of human food. Their “endocrine disrupting” properties are a matter of major research programmes. The present project aims at elucidating mechanisms of interaction of phytoestrogens and their metabolites with cytoskeletal proteins as the key macromolecules of which interaction with foreign chemicals leads to chromo-somal genotoxic damage. It is supposed that for such interac-tions thresholds may be defined which would allow definitions of No-Observed-Adverse-Effect-Levels (NOAEL). This is fundamental for setting health-based standards (e.g., ADI). Whereas in the past the research in this field had been centered on defining major interactions of estrogens and their metabolites with microtubular proteins, the present project will use functional tests of tubulin-motor protein interaction to describe the dose-response patterns of phytoestrogens and phytoestrogen metabolites, in relation to their chromosomal genotoxicity.
Added value of cooperation: Assisted by seed funding from CEFIC/LRI, the group in Dortmund, in cooperation with IMB, Jena, has adopted methods to study the function of cytoskeletal proteins and of influences of foreign compounds thereon. The issue is of considerable regulatory impact, as it will probably allow to define a subgroup of genotoxic compounds to which threshold levels may be assigned. The group in Maastricht has a long-standing expertise in methods of quantitative risk assessment. The combination of both will allow to develop new aspects for the regulatory risk assessment of genotoxic food constituents.


 

A3. Induction of DNA damage in human cells by ochratoxin A and other mycotoxins
        Degen (Dortmund) / Fink-Gremmels (Utrecht)

The mycotoxin ochratoxin A (OTA) is a widespread contaminant in human and animal food. In humans, an exposure to high dietary levels of OTA has been linked with chronic renal disease and with a higher incidence of urinary tract tumors. A genotoxic potential of OTA has been demonstrated in vitro and in vivo, but there is some controversy as to whether its action is direct or indirect. The project aims at identifying the nature of the genotoxic damage. UDS responses in human urothelial cell cultures,  micronucleus induction, single cell "COMET" assay and  the functional interaction of OTA with cytoskeletal proteins will be investigated. The most sensitive endpoint for damage induced by OTA will be characterized, and it will be assessed whether threshold concentrations for cellular effects can be established. This will be important for future risk assessment.
Added value of the cooperation: Both groups have been studying the genotoxicity of mycotoxins in the past using partly complementary techniques. The group of J. Fink-Gremmels has developed engineered cell lines in which the biotransformation-dependent mutagenic response to OTA exposure could be demonstrated by means of a reporter gene and subsequent sequence analysis. They also set up the Comet Assay for use in primary cell culture systems. The group of G.Degen uses unscheduled DNA-synthesis in primary cell cultures from human urothelial tissue and in porcine urinary bladder epithelial cell cultures and studies cell-type specific susceptibility to toxin induced oxygen radical formation and the expression of cell specific defence mechanisms.

A4. Interactions of dietary iodine deficiency with neonatal PCBs on thyroid function and brain development in rats
        Winneke (Düsseldorf) / Kleinjans (Maastricht)

Severe iodine deficiency can result in miscarriage, stillbirth, and congenital abnormalities. Iodine is required for the synthesis of thyroid hormones. These hormones, in turn, are required for brain development. Polychlorinated biphenyls (PCBs) are known to induce neurochemical and behavioural disruptions during the early development of humans and experimental animals. The hypothesis underlying the project predicts that PCB-related cognitive impairment is brought about by PCB-induced hypothyroidism. By combining an established iodine-deficiency model in rats with an established developmental PCB-exposure model the hypothesis will be tested that the combination of iodine deficiency with low-level PCB-exposure during early brain development will produce overadditive interaction in terms of hypothyroid effects and - consequently - impaired brain development.
Added value of the cooperation: The two laboratories contribute complementary research interests and experience having as the common denominator their longterm work on biological effects of polyhalogenated compounds. The Division of Neurobehavioral Toxicology  (Winneke) has a documented expertise in neurobehavioral, neurophysiological  and neuroendocrine effects of PCBs, whereas the Department of Risk Analysis and Toxicology (Kleinjans) contributes its expertise on thyroid dysfunction including thyroid hormone measurement, measurement of PCB metabolites and PCB risk assessment.

 A5. Rapid non-genomic actions of testosterone: Intracellular signalling mechanisms and isolation of the plasma membrane receptor of testosterone
        Wunderlich (Düsseldorf) / Rietjens (Wageningen)

Steroid hormones, in particular testosterone and testosterone derivatives, are widely used in animal production - legally in U.S.A., illegally in Europe. Adverse effects for meat consumers are currently considered negligible Also there is an enormous testosterone abuse by athletes and bodybuilders. Testosterone acts through intracellular androgen receptors (iAR) on gene expression of cells. Recent evidence, however, indicates that testosterone can also signal through unconventional membrane testosterone receptors (mTR) on the cell surface. The aim of this project is to isolate and characterize such mTR. The project of the Dutch partner investigates the interactive effects of testosterone and other anabolic agents through iAR at the level of gene expression.
Added value of the cooperation: The projects of both groups complement each other and have synergizing effects in several different aspects. The Dutch group investigates the interactive effects of testosterone and other anabolic agents on the level of gene expression using DDRT-PCR and PCR-assisted subtractive hybridization. Furthermore, they have developed a reporter gene assay  allowing the specific quantification of iAR-mediated effects. The mTR+-iAR--IC21 cells from the German laboratory will be used to study the mTR-mediated effects of real-life (veterinary) samples obtained by the Dutch group. At a later stage, when we have cloned and characterized the mTR, the German student will investigate the effect of mTR on testosterone effects mediated through iAR on gene expression in the Dutch group.

B1. Pulmonary inflammation and systemic effects due to ambient particulates
        Borm (Düsseldorf) / Bast (Maastricht)

Epidemiological studies have shown that exposure to ambient air pollution, including (ultra)fine particulates is well known to increase mortality and morbidity. Current hypotheses suggest that these particles induce inflammatory responses, such as the influx of neutrophils (PMN) to the lung and affect systemic mechanisms such as blood coagulation . It is the purpose of this study to investigate the effect of instillation of ambient particles on (i) PMN recruitment/adhesion and PMN induced toxicity in the rat lung, (ii) to evaluate particle translocation, and (iii) the release of vasoactive mediators from the lung. As a model the isolated perfused rat lung (constant flow) will be used, perfused with suspensions of neutrophils (PMN) isolated from human blood. Effect parameters are PMN adhesion and migration, lung and perfusate mediators of inflammation and vasoaction (MPO, NO, ACE, histamine)and effects of perfusate on isolated target tissues (heart, aorta). The model  will use anti-oxidants pre-treatment  along with (ambient) particle  instillation to ameliorate inflammation and protective capacity of the lung. We hypothesize that migration of inflammatory cells causes changes in lung permeability that allows translocation of ultrafine particles, and that anti-oxidants can inhibit these effects.
Exposure to ambient air pollution, including (ultra)fine particulates, SO2 and NO2 increases mortality and morbidity. One of the current hypotheses is that these factors induce inflammatory responses, challenge anti-oxidant responses in the lung and affect systemic mechanisms such as blood coagulation. It is the purpose of this study to investigate the effect of anti-oxidant modulation in the lung on leukocyte influx and leukocyte-induced toxicity after exposure to various ambient air pollutants. As a model the isolated perfused rat lung will be used. Effect parameters are vascular pressure, lung weight, leukocyte adhesion and migration, anti-oxidant levels and oxidative DNA damage. The model will use Se-depletion, vitamin E depletion and ambient particle instillation. We hypothesize that anti-oxidant levels in the lung as modified by nutritional modification affect the influx and migration of inflammatory cells, the subsequent damage and release of vaso-active mediators.
Added value of the cooperation: The two groups have collaborated for a large number of years and contribute expertise from highly  different laboratories. The IUF (Borm) is a lab which has an accent towards molecular-biological and histopathological techniques. The UM (Bast) is equipped to perform pharmacological experiments on lung perfusate as well as to determine anti-oxidant status and chemical degradation. In addition, the PhD will acquire knowledge and expertise in complementary areas as Toxicology-Risk assessment (IUF) and pharmacology-dietary modulation (UM).

B2. Role of dietary flavonoids in the adaptation of antioxidant enzymes to prooxidants and proinflammatory mediators
        Kahl (Düsseldorf) / Bast (Maastricht)

Flavonoids present in the diet are assumed to protect consumer health by their antioxidative action because many degenerative diseases have been linked to oxidative stress. Exogenous antioxidants may interfere with the adaptive alterations of gene expression, e.g. the induction of antioxidant enzymes, which occur in response to exposure to prooxidative and proinflammatory conditions. In addition, exogenous antioxidants may possess prooxidative properties themselves. It is the aim of the present project to examine whether flavonoids encountered in the diet inhibit the induction of antioxidant enzymes by prooxidants and proinflammatory cytokines and to elucidate the structure-activity relationship involved. In addition, it will be attempted to get insight into the signaling pathways leading to antioxidant enzyme induction by prooxidants.
Added value of the cooperation: The two collaborating laboratories are specialized in complementary fields.  While the laboratory of A. Bast in Maastricht has a broad background in structure-activity studies of flavonoids and will supervise the choice of suited flavonoids for the project and study their antioxidant/prooxidant balance, the regulation of antioxidant enzymes is a main topic in the laboratory of R. Kahl in Düsseldorf where molecular biological methods such as Northern blotting, EMSA and transfection will be provided for the cell culture experiments.

B3. Cooperative interactions of antioxidant micronutrients
        Sies and Stahl (Düsseldorf) / Bast (Maastricht)

Antioxidants interact synergistically and thus balanced mixtures of dietary antioxidants may be superior to an increased consumption of a single compound in disease prevention. In order to study cooperative interactions and synergisms, unilamellar liposomes will be used to test systematically combinations of antioxidants. The hydrophilic core space will be loaded with hydrophilic antioxidants such as ascorbic acid; the surrounding lipid bilayer can be loaded with hydrophobic compounds such a-tocopherol or carotenoids. The experiments are designed to allow for the quantification of lipid peroxidation and measurements of oxidative damage to proteins. Based on the results obtained with the liposomal system appropriate antioxidant mixtures will be selected and tested for antioxidant activity in cell culture. Additionally, ESR studies will be performed to obtain information on the stability of radicals formed during oxidation in order to get insight in mechanisms of antioxidant interaction.
Added value of the cooperation: The cooperating laboratories are both specialized in the field of antioxidant research but their focus is on different classes of compounds and they apply different techniques. Prof.Bast´s laboratory has a strong background regarding structure-activity relationships of flavonoids and routinely uses ESR spectroscopy to evaluate mechanisms of antioxidants action. Carotinoids and tocopherols are a major research interest in the laboratory of Prof.Sies and Dr.Stahl. Several models and cell culture systems are established to study antioxidants biological effects and they are qualified in HPLC analyses. The cooperation will provide additional scientific information and increase the methodological knowledge of the PhD student.

B4. Immunomodulation and altered gene expression induced by oral uptake of nickel (Ni) and zinc (Zn), respectively
        Gleichmann (Düsseldorf) / van Loveren (Utrecht)

This project analyzes the beneficial dietary effects of metal ions on two immunotoxicological mouse models established in Duesseldorf: induction of allergic contact hypersensitivity (ACH) to Ni, and diabetes induced with multiple low doses of  streptozotocin (MLD-STZ). In both models, oral administration of metal ions (Ni in the case of ACH, Zn in the case of MLD-STZ-induced diabetes) prior to the disease-inducing treatment was shown to be protective. Applying the DNA microarray technique  to both disease models will greatly expand the analytical scope for identification of the genes and molecules, respectively, that are involved in the above-mentioned protective effects of dietary Ni and Zn in that it allows to study a broad spectrum of genes coding for different immunological as well as non-immunological functions.
Added value of the cooperation: The two coordinators, E. Gleichmann (MIU), and H. van Loveren (RIVM)  know each other for 15 years. They have cooperated in two EU projects on immunotoxicology. The laboratories of E. Gleichmann and H. Gleichmann-Töpper have long-standing expertise in models of allergic contact hypersensitivity and murine diabetes, respectively, as well as in immunological techniques. The DNA microarray technique to be used for screening gene expression at the mRNA level has been established in the laboratory of H. van Loveren at RIVM. In addition, several different types of array shall be used; these are currently being developed and tested at RIVM.

B5. Purinergic receptors of human macrophages: Influence of polychlorinated biphenyls and antioxidants on intracellular signal transduction and redox systems
        Wiegand and Borm  (Düsseldorf) / Bast (Maastricht)
 

While coplanar PCB are agonists of the aryl hydrocarbon (Ah) receptor and are assumed to exert their actions on gene expression and cell cycle via dioxin-like pathways the ortho-substituted non-planar PCB act via non-dioxin-like effects which are poorly characterized. The hypothesis underlying the present project suggests that these compounds interfere with intracellular signal transduction. This increases in a concentration dependent manner the purinergic receptor mediated cellular calcium levels and may thus modulate apoptosis/growth regulation processes of the cell. It is the aim of the project to a) more fully characterize the action of PCB on purinergic signal transduction and b) to investigate whether antioxidants present in food can interact with the PCB action. Synergistic or antagonistic actions on the activation of purinergic receptors may influence proinflammatory responses and growth regulation. This could be of great interest for preventive clinical approaches.
Added value of the cooperation: Purinergic signal transduction and its consequences can be studied in the two cooperating laboratories by different methodological approaches. The group of H.Wiegand  is equipped to perform electrophysiological techniques and microspectrofluorometric techniques whereas the group of A. Bast  is specialised on biochemical and pharmacological investigations including the measurement of the redox status of cells and of second messenger concentrations as well as the determination of cytokine and iNOS expression.
 

Training program
 

1. Introductory course in toxicology on CD-ROM, consisting of life recorded lectures in Real Audio and accompanying overhead sheets and slides in Powerpoint

A parallel  course in basic toxicology is  held in each partner university during the first semester of the educational programme. For this, a CD-ROM-based basic training course in toxicology has been developed by the Dutch Postgraduate Education in Toxicology (PET). The course consists of 23 lectures ranging from toxicity mechanisms to organ-specific toxic effects, roughly covering the topics from the handbook “Toxicology, principles and applications” (eds.Niesink et al.). The students  work on the study units at their own  PC. A helpdesk is available in case problems of technical or educational nature should arise. Progress is verified in oral sessions with a subgroup of the supervisor panel who are responsible for the study unit to be discussed. Acquisition of the required knowledge will be tested by a written examination at the end of the course.
 

2. Course modules

The major part of the educational programme consists of  modular courses on central topics of toxicology with a duration of 1-3 weeks which is based on the Postgraduate Eduation Programme in Toxicology (PET) established in the Netherlands. Seven modules are part of  of the common educational program of the Graduate College:

3. Courses on specific techniques in biomedical research

Laboratory courses of one week in laboratories at the home universities:

4. Excursions to laboratories in the nearby industry
 

5. Common colloquia with Dutch PhD students on the progress of students´ theses
to be held once a year (2 days) in the presence of the supervisors. First colloquium: 10/02.
 

6. Common workshops in collaboration with EUROTOX

EUROTOX Training and Discussion sessions on specific topics to be addressed by international experts (2 days). The workshops will be open for scientists from outside the Graduate College and from other countries. First EUROTOX workshop: "Diet and Cancer", 04/03.
 

7. Seminars to be held by visiting scientists.
 
 
 


19.05.2003, E-mail