Publications by authors named "J Brtko"

The present minireview traces the road leading to discovery of selenium, formerly appointed as a toxic element that became later a bioelement, which is necessary for the proper functioning of living organisms. Selenium occurs in human and animal bodies either in the form of seleno-Lcysteine or its dimeric form seleno-L-cystine as a crucial component of selenoenzymes or selenoproteins. Selenium atom represents an integral component of the enzyme active site of different forms of glutathione peroxidase, which catalyzes conversion of hydrogen peroxide and organic hydroperoxides into the water and corresponding alcohols.

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Several commercially available triorganotin compounds were previously found to function as agonist ligands for nuclear retinoid X receptor (RXR) molecules. Triphenyltin isoselenocyanate (TPT-NCSe), a novel selenium atom containing a derivative of triorganotin origin, was found to represent a new cognate bioactive ligand for RXRs. TPT-NCSe displayed a concentration- and time-dependent decrease in the cell viability in both human breast carcinoma MCF-7 (estrogen receptor positive) and MDA‑MB‑231 (triple negative) cell lines.

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This review traces the road leading to the demonstration of a variety of kojic acid chemical and biological properties. It illustrates the biological effects of several synthetic kojic acid derivatives. Besides the main capability of kojic acid to inhibit the activity of tyrosinase in melanin synthesis, the focus is also on antibacterial, antifungal, antiproliferative, anti-inflammatory, and other biological activities of kojic acid derivatives, which may be applicable in medicine.

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Intensive investigation for novel antiproliferative and cytotoxic effective chemical compounds is currently concentrated on structurally modified agents of natural or synthetic source. The selenium derivative of triorganotin compound, triphenyltin isoselenocyanate (TPT-NCSe) caused higher cytotoxicity in hormone sensitive MCF 7 (IC 50-250 nM) in comparison with triple-negative MDA-MB-231 breast carcinoma cell line (IC 50-450 nM) as determined by MTT assay. Measurement of DNA damage showed presence of crosslinks in both cell lines treated by increasing TPT-NCSe concentrations.

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Using H9C2 cardiomyoblasts, we have shown that all-trans retinoic acid (ATRA), the biologically active metabolite of vitamin A, affects mitochondrial dynamics and functions. The low dose (10 nM) ATRA stimulates the expression of nuclear retinoid receptors and induces mechanisms that are protective against severe local damage caused by laser irradiation at the mitochondrial level. These changes include increased density of the mitochondrial network, higher number of mitochondrial junctions, and enhanced mitochondrial velocity.

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