The presence of chemicals and the destruction of freshwater habitats have been addressed as one of the reasons for the decline in the amphibians' populations worldwide. Considering the threat that these animals have been suffering in tropical regions, the present study tested if the Brazilian legislation, concerning the permissive levels of lithium and selenium in water bodies and effluents, warrants the protection of aquatic life. To do so, we assessed the metabolic, immunologic, and histopathologic alterations in liver samples of American bullfrog (Lithobates catesbeianus), at the premetamorphic stage, through biomarkers indicative of general energetic status, i.e., glucose, lipid, and protein metabolism using biochemical and histochemical approaches. The immunologic responses were assessed by the quantification of melanomacrophage centres (MMCs); the histopathologic evaluation of the liver sections was also performed. The assay was carried out over 21 days with two periods of sampling (after 7 and 21 days) to assess the effects of exposure over time. The animals were exposed to the considered safe levels of lithium (2.5 mg L-1) and selenium (10 μg L-1), both, isolated and mixed. The exposed animals showed alterations in glucose and lipid metabolism throughout the experiment. The intense presence of MMCs and histopathological responses are compatible with hepatotoxicity. The toxicity expressed by the employed animal model indicates that the Brazilian environmental legislation for the protection of aquatic life needs to be updated. With this study, we intend to provide data for better environmental policies and bring attention to sublethal effects triggered by the presence of contaminants in the aquatic environment.
- MeSH
- Larva MeSH
- Lithium MeSH
- Rana catesbeiana MeSH
- Selenium * toxicity MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Brazil MeSH
- United States MeSH
Here we present the preparation of 14 pairs of cis- and trans-diammine monochlorido platinum(II) complexes, coordinated to heterocycles (i.e., imidazole, 2-methylimidazole and pyrazole) and linked to various acylhydrazones, which were designed as potential inhibitors of the selenium-dependent enzymes glutathione peroxidase 1 (GPx-1) and thioredoxin reductase 1 (TrxR-1). However, no inhibition of bovine GPx-1 and only weak inhibition of murine TrxR-1 was observed in in vitro assays. Nonetheless, the cis configured diammine monochlorido Pt(II) complexes exhibited cytotoxic and apoptotic properties on various human cancer cell lines, whereas the trans configured complexes generally showed weaker potency with a few exceptions. On the other hand, the trans complexes were generally more likely to lack cross-resistance to cisplatin than the cis analogues. Platinum was found bound to the nuclear DNA of cancer cells treated with representative Pt complexes, suggesting that DNA might be a possible target. Thus, detailed in vitro binding experiments with DNA were conducted. Interactions of the compounds with calf thymus DNA were investigated, including Pt binding kinetics, circular dichroism (CD) spectral changes, changes in DNA melting temperatures, unwinding of supercoiled plasmids and ethidium bromide displacement in DNA. The CD results indicate that the most active cis configured pyrazole-derived complex causes unique structural changes in the DNA compared to the other complexes as well as to those caused by cisplatin, suggesting a denaturation of the DNA structure. This may be important for the antiproliferative activity of this compound in the cancer cells.
- MeSH
- Enzyme Activation drug effects MeSH
- Chondroitin analogs & derivatives chemistry pharmacology MeSH
- DNA chemistry drug effects MeSH
- Enzymes metabolism MeSH
- Glutathione Peroxidase antagonists & inhibitors MeSH
- Inhibitory Concentration 50 MeSH
- Aspartic Acid analogs & derivatives chemistry pharmacology MeSH
- Molecular Structure MeSH
- Mice MeSH
- Cell Line, Tumor MeSH
- Organoplatinum Compounds chemical synthesis chemistry pharmacology MeSH
- Oxidation-Reduction MeSH
- Platinum chemistry pharmacology toxicity MeSH
- Cell Proliferation drug effects MeSH
- Selenium chemistry pharmacology toxicity MeSH
- Cattle MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The normotensive (Wistar) and spontaneously hypertensive (SHR) rats were examined to assess the response of the organism to selenium (Se) overdose. Moreover, the effect of zinc (Zn) and vitamin E, i.e. dietary components interacting in many biochemical processes with Se, on the Se uptake was evaluated. The control group was fed an untreated diet, and the diets of two other groups were overdosed with Se in the form of sodium selenite (9 mg/kg) and supplemented with Zn (13 mg/kg). Two experimental groups were fed a diet supplemented with Zn (13 mg/kg) and Se at an adequate level (0.009 mg/kg); a half of the animals was supplemented with vitamin E. The results showed significant differences in the Se contents between the rat strains in case of Se-overdosed groups, where in the liver and kidney tissue Se contents of SHR rats exceeded 3- and 7-fold the normotensive ones. The Se uptake was altered by the vitamin E; no effect of Zn was observed. Activities of antioxidant enzymes were determined in the animal tissues indicating different patterns according to rat strain, tissue analysed, and administered Se dose. Thus, Se overdose, for instance, via an incorrectly prepared dietary supplement, can result in serious imbalances of the biochemical status of the animals.
- MeSH
- Antioxidants administration & dosage therapeutic use MeSH
- Drug Therapy, Combination MeSH
- Rats MeSH
- Rats, Inbred SHR MeSH
- Rats, Inbred WKY MeSH
- Dietary Supplements MeSH
- Drug Overdose drug therapy metabolism MeSH
- Selenium administration & dosage toxicity MeSH
- Trace Elements administration & dosage therapeutic use toxicity MeSH
- Vitamin E administration & dosage therapeutic use MeSH
- Zinc administration & dosage therapeutic use MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The function of selenium in an organism is mediated mostly by selenoproteins including glutathione peroxidase. Glutathione peroxidase is a potent anti-oxidative enzyme, scavenging a variety of peroxides. The green alga Scenedesmus quadricauda was used to investigate the relationship between the toxicity of selenium and the glutathione peroxidase activity. Selenium resistant strains SeIV and SeVI were synchronized and grown in high concentrations of Se (selenite or selenate). As a measure of selenium toxicity the EC(50) values were determined. During growth of the untreated wild type, glutathione peroxidase activity increased slightly and then declined gradually until the end of the cell cycle. A similar pattern was observed in untreated resistant strains and when resistant strains were grown in the presence of selenium in the oxidation state to which they were resistant. In the wild type cultivated with 50 mg Se L(-1) (selenite or selenate), activity increased to a high level and slowly declined until the end of the cell cycle. Similarly, activity increased in strains SeIV and SeVI when grown in the presence of selenium in the oxidation state to which they were not resistant. We followed the effect of selenium on the ultrastructure of S. quadricauda. After exposure to selenite, the chloroplast membranes of wild type were reorganized into thick bundles of thylakoids and the stroma became granulose. When selenate was added, the chloroplast of wild type had a fingerprint-like appearance, the stroma became less dense and starch production increased. In selenium resistant strains, when treated with the selenium form to which they were resistant, the chloroplast was affected, but not to such an extent as in the wild type. The activity of glutathione peroxidase in Scenedesmus was affected by selenium in an oxidation state-dependent manner. The most apparent effects of selenium on the ultrastructure involved impairment of the chloroplast and the overproduction of starch.
- MeSH
- Cell Cycle drug effects physiology MeSH
- Chloroplasts drug effects metabolism ultrastructure MeSH
- Stress, Physiological MeSH
- Plants, Genetically Modified MeSH
- Glutathione Peroxidase metabolism MeSH
- Culture Techniques MeSH
- Scenedesmus cytology drug effects enzymology physiology MeSH
- Selenium administration & dosage analysis toxicity MeSH
- Sodium Selenite administration & dosage toxicity MeSH
- Selenium Compounds administration & dosage toxicity MeSH
- Toxicity Tests MeSH
- Dose-Response Relationship, Drug MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The aim of this paper is to review current knowledge of the significance of pork as a source of Se for human consumption, and to evaluate the selenium content in pork produced in the Czech Republic. Selenium has an important role in human health. Pork could possibly be an important source of Se for the human diet. The Se content in meat can be increased by a higher dietary intake of selenium in animal feed. The magnitude of this increase is higher when organic Se from Se-enriched yeast is ingested. Selenium intoxication in pigs occurs only when very high Se concentrations are used in their diet (more than 5 mg/kg of Se). Organic Se sources produce fewer clinical signs of high toxicity than inorganic sodium selenite. Organic Se does not have a negative effect on meat quality. Altogether, 135 pork samples from 9 different herds in the Czech Republic were collected and analyzed for Se content. The average selenium content found in pork in our study was 87.10 microg/kg. Because the average annual consumption of pork in the Czech Republic is 42.0 kg per person, the annual selenium intake from pork represents 18.2% of the minimum yearly requirement for humans. The results of our study show that pork contributes significantly to the selenium intake of the human population in the Czech Republic.
Mining for coal and its utilization have various impacts on the surrounding environment. Huge volumes of waste materials which are by-products of both the underground and open cast coal mining, pose one of the major environmental hazards in addition to air pollution caused by coal burning in power plants in the Czech Republic. Some of these risks could be reduced when having accurate and comprehensive data on coal quality. Statistical data processing of almost 35,000 coal samples from Late Paleozoic and Tertiary coal basins of the Czech Republic provided a unique information on the quality of lignite, sub-bituminous and bituminous coals and anthracites including the content of toxic trace elements (As, Be, Hg, Pb and Se). In this context related environment and health risks and protection implications are discussed.
- MeSH
- Arsenic adverse effects toxicity MeSH
- Beryllium adverse effects toxicity MeSH
- Ecology statistics & numerical data MeSH
- Research Support as Topic MeSH
- Fossil Fuels statistics & numerical data adverse effects MeSH
- Air Pollutants classification MeSH
- Humans MeSH
- Lead adverse effects toxicity MeSH
- Mercury adverse effects toxicity MeSH
- Selenium adverse effects toxicity MeSH
- Coal classification adverse effects toxicity MeSH
- Check Tag
- Humans MeSH
- Geographicals
- Czech Republic MeSH
- MeSH
- Safety MeSH
- Immune System drug effects MeSH
- Liver physiopathology pathology drug effects MeSH
- Rats MeSH
- Drug-Related Side Effects and Adverse Reactions MeSH
- Selenium administration & dosage toxicity MeSH
- Toxicity Tests MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Comparative Study MeSH
- MeSH
- Anticarcinogenic Agents therapeutic use MeSH
- Child MeSH
- Adult MeSH
- Glutathione Peroxidase physiology chemistry MeSH
- Humans MeSH
- Organoselenium Compounds immunology toxicity MeSH
- Renal Insufficiency metabolism MeSH
- Selenium analysis immunology toxicity MeSH
- Selenium Compounds analysis immunology MeSH
- Pregnancy MeSH
- Free Radicals antagonists & inhibitors MeSH
- Check Tag
- Child MeSH
- Adult MeSH
- Humans MeSH
- Male MeSH
- Pregnancy MeSH
- Female MeSH
- Publication type
- Review MeSH
2., völlig überarbeitete und erweiterte Aufl. X, 234 s. : il., grafy ; 20 cm
