Division of Toxicology

The toxic effects of organophosphorus compounds (OPs), as well as the existing and new potential antidotes are studies in the framework of the project Therapeutic effect of newly synthesised compounds in organophosphorus poisoning. The general toxicological activity of OPS is based on the irreversible inhibition of hydrolytic enzymes; essential acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These are compounds with primarily act on the cholinergic nervous system and unfortunately, besides being used in agriculture, public health and veterinary and human medicine, may also be used as warfare nerve agents. Despite many studies and findings, a suitable antidote with a satisfactory effectiveness in OP treatment has still not been found. Therefore, finding effective antidotes is one of key segments in this field of research.

Mycotoxins are metabolites of various species of mould with toxic, carcinogenic, genotoxic, mutagenic and teratogenic properties. The toxic effects of mycotoxins are investigated in the framework of the project Toxic effects of mycotoxins on humans and animals. The problem of food contamination with mycotoxins is more and more pronounced because an increasing number of foodstuffs come from tropic countries in which the possibility of mould growth and mycotoxin contamination is higher. Besides, more and more “healthy food” is consumed, i.e. food with no pesticides, which makes mould and their metabolite (mycotoxin) contamination more frequent. In the framework of this project, the mechanism of toxicity is explored, and their concentrations are measured in biological material and food.

• Biological monitoring of aromatic hydrocarbons:
  • determination of benzene, toluene, ethylbenzene and xylene isomers (BTEX) and their metabolites in biological samples using gas chromatography (GC);
  • selection of optimal biological indicators in different samples and their comparison;
  • assessment of exposure of working and general population to organic solvents using biological monitoring;
  • assessment of effects on health.
• Identification of drug abuse in selected populations:
  • development of methods for detecting drugs in hair and urine using gas chromatography mass spectrometry (GC-MS);
  • comparison of biological indicators of exposure;
• Assessment of human exposure to passive smoking:
  • determination of nicotine and its metabolite cotinine in hair and urine using gas chromatography mass spectrometry (GC-MS);
  • assessment of harmful effects on health in vulnerable groups of people (children, pregnant women, puerperas and other).

PROFESSIONAL ACTIVITY

• The activity of cholinesterases in whole blood and plasma is measured in workers occupationally exposed to pesticides (organophosphorus and carbamate compounds)
• determining indicators of exposure to volatile hydrocarbons (benzene, toluene isomeric xylenes, ethylbenzene, styrene, phenol,) in urine and blood
• drugs of abuse analyses (amphetamines, opiates, cocaine) in human hair and urine; serum lidocaine analysis

• Ecogenetic studies and biomonitoring of populations occupationally exposed to various physical and chemical mutagens: ionising radiation (X- and γ-radiation, radioactive isotopes), non-ionising radiation (microwave radiation, radiofrequency radiation), ultrasound and genotoxic chemicals (antineoplastic/cytotoxic drugs, anaesthetics, pesticides, organic solvents, heavy metals and their compounds etc.).
• Assessment of genotoxic effects is carried out using human peripheral blood lymphocytes and by applying various genetic markers which allow for an early detection of biological effects. These involve chromosomal aberrations, micronuclei and sister chromatid exchange. A sensitive detection of primary genome damage is done using microgel electrophoresis or comet assay under alkaline and neutral conditions. Standard cytogenetic techniques are complemented with specific techniques of chromatin staining and the FISH technique. For the assessment of individual genome sensitivity, chromatid breakage assay is applied. Genotoxic effects are also determined with in vivo-micronucleus assay in rodents.
• Ecogenetic studies aimed at assessing the value of biomarkers of exposure, effect and genome sensitivity in general population in the Republic of Croatia.
• Continuous biomonitoring of populations of workers occupationally exposed to different mutagens in their working environment (in line with Croatian regulations).
• Assessment of cytogenetic risk in cases of accidents.
• Genotoxicological studies under in vivo conditions in laboratory animals.
• Genotoxicological studies under in vitro in cell lines of human and animal origin.

CYTOGENETIC SERVICES

1. Structural chromosomal aberrations in peripheral blood lymphocytes (karyogram)
2. Sister Chromatid Exchange (SCE)
3. Micronucleus assay (MN)
4. Comet assay

• Scientific research in experimental biomedicine in the framework of local and foreign collaboration projects
• Mentoring graduate and master theses in the field of biomedicine

SPECIFIC RESEARCH INTERESTS

Expression of membrane transporters of organic anions and cations, glucose, hydrogen ions and water in kidneys and other organs of laboratory animals (mice, rats), pigs and humans:

• Sex and species specific differences in transporter expression
• Regulation of transporter expression with sex hormones at the level of mRNA and/or proteins
• Regulation of transporter expression by intracellular vesicular transport; the role of cytoskeleton
• Relationship between transporter expression and (re)absorption and/or secretory organ functions

Experimental toxicity of some heavy metals (cadmium, mercury, lead):

• Mechanism of toxicity of heavy metals in cells along the rat nephron
• Role of metallothionein as mediator and/or protector against toxicity induced by heavy metals
• Role of cell membrane transporters in the transport and toxicity of heavy metals
• Effect of toxic metals on:
  • structure and function of cytoskeleton
  • intracellular vesicular transport
  • expression of cell membane transporters in mammalian kidneys and liver

Physiology, pathophysiology and toxicology of hydrogen ion transporters in male and female reproductive system:

• Hydrogen ion transporters in cells along the male and female reproductive systems in rats and humans
• Morphological and functional features of cells excreting hydrogen ions in the reproductive system in experimental toxicity induced by heavy metals in male and female rats

FOREIGN ASSOCIATES

• Naohiko Anzai, M.D., Ph.D., Pharmacology and Toxicology, Kyorin University School of Medicine, Tokyo, Japan
• Hermann Koepsell, M.D., Ph.D., Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
• Gerhard Burckhardt, M.D., Ph.D. c/o Prof. Birgitta C. Burckhardt, Ph.D., Vegetative Physiology and Pathophysiology, University of Göttingen, Göttingen, Germany
• Prof. Frank Thevenod, M.D., Ph.D., Physiology and Pathophysiology, Department of Human Medicine, School of Medicine, University of Witten/Herdecke, Witten, Germany