Volume 3 (2010): Issue 3 (September 2010)

Communication - Dialogue - Co-operation - Solving problems. These are the words of nowadays Europe. Such approaches should be used in broad spectrum of life as well as in toxicology. It is therefore admirable that EUROTOX commissars, mainly past-president Prof. Liesivuori, invited all heads of European toxicological societies to discuss current issues of toxicology in Europe during IUTOX meeting held in Barcelona in July 2010. Renowned scientists and regulatory officers from Government, Industry and Academia made appearance and talked about contribution of toxicological research to society, importance of communication and education. The strategic meeting was successful. Prof. Liesivuori expressed gratitude to all delegates for the great suggestions and key findings resulting from the brainstorming sessions conducted during the meeting. Majority of delegates agreed that education in toxicology and related fields is the top priority for future. Communication towards society, in the sense of explaining possible risks, should be an important concern as well. Taking a good example from EUROTOX, on the verge of summer the Slovak Toxicology Society SETOX organizes meeting of the toxicological societies from the Central Europe, i.e. Slovak, Czech, Polish, Austrian and Hungarian societies of toxicology. First positive step was done by Visegrad Fund and Federation of European Toxicologists & European Societies of Toxicology, which supported this meeting. It is essential for successful co-operation to establish strong connections, which can be further crucial for meaningful and highly profitable information to society.

Ranged among laminopathies, Hutchinson-Gilford progeria syndrome is a syndrome that involves premature aging, leading usually to death at the age between 10 to 14 years predominatly due to a myocardial infarction or a stroke. In the lecture I shall overview the importance of molecular cell biology investigations that led to the discovery of the basic mechanism standing behind this rare syndrome. The genetic basis in most cases is a mutation at the nucleotide position 1824 of the lamin A gene. At this position, cytosine is substituted for thymine so that a cryptic splice site within the precursor mRNA for lamin A is generated. This results in a production of abnormal lamin A, termed progerin, its presence in cells having a deleterious dominant effect. Depending on the cell type and tissue, progerin induces a pleiotropy of defects that vary in different tissues. The present endeavour how to challenge this terrible disease will be also mentioned.

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions.

In opposition to toxicology of mammals piscine toxicology is closely connected with the conditions of external environment. The aquatic environment is necessary for embryonic development and after hatching during short or long-lasting larval period of most fish species. An aquatic environment is polluted by many industrial and agricultural wastes. Ammonia as a toxic and common compound in water have negative influence for aquaculture especially in intensive fish culture, recirculation system and hatchery facilities. Acute toxicity of ammonia was investigated in carp Cyprinus carpio L. and developmental stages of chub Squalius cephalus L. Changes in the peripheral blood characteristics and hemopoietic tissues of carp occurred after exposition to ammonia in acute tests and 3, 5 and 10 weeks sublethal concetration. The observed increase of the concentration of most amino acids in fish intoxicated with amonia suggests that the process reflects detoxication of ammonia which takes place both in the brain and muscles after 3 weeks of exposition. Phenol intoxication tests induced considerable unfavorable changes in the blood and dystrophic and necrobiotic lesions in tissues of fish leading to dysfunction both hemopoietic and reproductive processes.

In study on fish reproduction disruptors the influence of oxygenated polycyclic hydrocarbons (17-β-estradiol, 4,7-dihydroxyisoflavone, 1,6-dihydroxynaphthalene and 1,5-dihydroxynaphthalene) and oxygenated monocyclic hydrocarbons (phenol, 4-n-heptylphenol, 4-n-buthylphenol, 4-sec-buthylphenol; 4-tert-buthylphenol) was assessed using histopathological methods. It was established that examined oxygenated aromatic hydrocarbons both natural (17-β-estradiol and 4,7-dihydroxyisoflavone) and synthetic can disrupt the differentiation of primary and secondary sex traits in pikeperch Sander lucioperca L. The chronic activity of these "biomimetics of estrogen" can lead to the disappearance of natural fish population. In vivo and in vitro tests were used to exam dibutyl phthalate and butyl benzyl phthalate impact on the development of the reproductive system of pikeperch. Additional as multigenerational studies are needed to clarify influence long term exposure of fish to environmental concentrations of endocrine disrupting chemicals.

Hydrogen peroxide used in fish therapy is known to be toxic for sensitive species. In our work safe concentrations and exposure times was evaluated for ide Leuciscus idus L. and pike Esox lucius L. fry. The intensity of lesions in gills, skin, pseudobranch and thymus of exposed fish were connected with the time of bath.

Actually anesthetics are routinely required during stressful procedures with fish, but data regarding the safety of individual anesthetics to different fish species are still few and insufficient. The influence of clove oil, MS-222 and 2-phenoxyaethanol anesthesia on fish organism was investigated in our faculty with cooperation with Research Institute of Fish Culture and Hydrobiology, Vodnany, Czech Republic.

Ischaemia and reperfusion (I/R) play an important role in human pathophysiology as they occur in many clinical conditions and are associated with high morbidity and mortality. Interruption of blood supply rapidly damages metabolically active tissues. Restoration of blood flow after a period of ischaemia may further worsen cell injury due to an increased formation of free radicals. The aim of our work was to assess macroscopically the extent of intestinal pathological changes caused by mesenteric I/R, and to study free radical production by luminol enhanced chemiluminescence (CL) of ileal samples. In further experiments, the antioxidative activity of the drugs tested was evaluated spectrophotometrically by the use of the DPPH radical. We studied the potential protective ex vivo effect of the plant origin compound arbutin as well as of the pyridoindole stobadine and its derivative SMe1EC2. I/R induced pronounced haemorrhagic intestinal injury accompanied by increase of myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAGA) activity. Compared to sham operated (control) rats, there was only a slight increase of CL response after I/R, probably in association with neutrophil increase, indicated by enhanced MPO activity. All compounds significantly reduced the peak values of CL responses of the ileal samples ex vivo, thus reducing the I/R induced increase of free radical production. The antioxidants studied showed a similar inhibitory effect on the CL response influenced by mesenteric I/R. If proved in vivo, these compounds would represent potentially useful therapeutic antioxidants.