PubMed Health⌕ Search

Biomedical subjects

J Skolimowski

Publications and source records attributed to J Skolimowski.

At least 19 recordsLinked to original sources
PubMed2003

Induction of chromosome aberrations in cultured human lymphocytes treated with ethoxyquin.

The chromosomal aberration test was employed to investigate the effect in vitro of a known antioxidant and food preservative, ethoxyquin (EQ, 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) on human chromosomes. The studies were undertaken because there are no published in vitro data on genotoxicity of EQ in mammalian cells and there are many reports pointing out that it may be harmful to animals and human beings. Lymphocytes obtained from three healthy donors were incubated with EQ (0.01-0.5mM) both with and without metabolic activation. Stability studies performed by HPLC analysis showed that EQ was stable under the conditions of the lymphocyte cultures. The results of the chromosome aberration assay showed that EQ induces chromosome aberrations: gaps and breaks as well as dicentrics and atypical translocation chromosomes.

Cells, Cultured↗
PubMed2001

Structure-activity relationship studies of protective function of nitroxides in Fenton system.

The aim of this study was to evaluate the effect of piperidine nitroxides and their amine precursors on deoxyribose oxidation in the Fenton system. Protecting activity of nitroxides was found to be concentration-dependent and strongly influenced by ring substituents, while secondary amines did not provide any protection. The reported results suggest a mechanism of nitroxide action through iron oxidation rather than through direct scavenging of hydroxyl radicals. Moreover, presented data point to the danger of interference of nitroxides during the TBARS assay procedure.

Amines↗
PubMed1997

Rutoxyl [rutin/4-acetamide-1-hydroxy-2,2,6,6-tetramethylpiperidinium] is a new member of the class of semi-natural products of high pharmacological potency.

A novel complex, Rutoxyl [rutin/4-acetamide-1-hydroxy-2,2,6,6-tetramethylpiperidinium] was synthesized and its structure and anticancer activity were investigated. The results reported here are consistent with our idea, that the formation of such a complex of two biologically active molecules: polyphenolic flavonoid antioxidant (Rutin) and nitroxylamine of nitroxide antioxidant (Tempace), stabilized by hydrogen bond(s) can result in a supra-additive properties.

Animals↗
PubMed1996

Tempace and troxyl-novel synthesized 2,2,6,6-tetramethylpiperidine derivatives as antioxidants and radioprotectors.

Two novel 2,2,6,6-tetramethylpiperidine derivatives (Tempace and Troxyl) were synthesized and their capacity to act as scavengers of superoxide, inhibitors of iron and ascorbate-driven Fenton reaction and radioprotectors was tested. The possibility for one-electron oxidation of novel compounds by heme-ferryl species was also examined. The results clearly indicate that Tempace and Troxyl are acting as promising antioxidants and radioprotectors thus providing a base for further investigations and pharmacological applications.

Antioxidants↗
PubMedDate not supplied

Antiproliferative and cytotoxic effects of N,N-diethylaminoethyl ethers of flavanone oximes: a comparison with anthracycline(s), anthraquinone and nitroxides action.

Since flavanone oximes derivatives (ethers) have been shown to modulate the growth of Yoshida Sarcoma cells in vivo and to induce apoptosis, the effects of these substances on immortalized cell lines growth were examined. Cell viability and sensitivity to investigated substances was measured by the modified tetrazolium salt (MTT) assay. The antiproliferative effects were expressed as IC50 and IC90, respectively. There were very substantial differences in the dose-dependency of the observed antiproliferative and cytotoxic effects. The structure-activity relationship was evident and revealed that the substitution at B-ring of molecule seems to be an important factor in flavanone oxime (ether) potency. Compared to anticancer drugs (doxorubicin, aclarubicin and mitoxantrone) flavanone oximes displayed cytotoxicity at considerably higher concentrations. The antiproliferative action of the investigated model nitroxides depended on the free radical part of the molecule. N-hydroxy derivative (reduced cation form) did not influence cells proliferation and nor display any cytotoxicity at the applied range about 60 times higher than those of flavanone derivatives. Taken together it seems reasonable to suggest that flavanone oxime(s) (ethers) as compared with antracycline(s), anthraquinone and nitroxides might be especially good candidates for in the future development of new therapeutic techniques.

3T3 Cells↗
PubMedDate not supplied

TTT, a novel free radical spin trap, induces apoptosis in sarcoma Yoshida cells in vivo: comparative investigations of its cytotoxicity in vitro.

In light of our previous SAR studies on nitroxides acting as less toxic anticancer agents, antioxidants and radioprotectors, we designed and tested, in vivo an in vitro, a new triradical spin trap -N,N',N"-tris-(l-oxyl-2,2,6,6-tetramethylpiperidine-4-yl)-1,3, 5-tnazine-2,4,6-triamine (TTT). The ability of TTT to act as an antitumor agent in vivo was investigated in pharmacological tests. The administration of TTT to rats bearing 3 day-old Sarcoma Yoshida (promotion phase of the disease) led to induction of apoptotic cell(s) death. Our results clearly indicated the suggested involvement of the free radical moiety of piperidine ring(s), thus indicating that the anticancer activity of nitroxide(s) may involve its intracellular redox reactions. To assess the relationship between the apoptotic effects of TTT in vivo and its possible cytotoxicity, we determined the relative antiproliferative and cytostatic potential of TTT in vitro as compared with this of the anticancer drugs: doxorubicin, aclarubicin and mitoxantrone, currently used in clinical practice in Poland. We found that TTT inhibits the growth and proliferation of two immortalized cell types-hamster B14 cell line and mouse NIH 3T3 fibroblasts which we used as a model for neoplastic phenotype, in a dose-dependent manner.

3T3 Cells↗
PubMedDate not supplied

Metexyl (4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl) as an oxygen radicals scavenger and apoptosis inducer in vivo.

A stable nitroxide radical named Metexyl (4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl) was synthesized and its antioxidant and antitumor properties were investigated and compared with these of another nitroxide derivatives previously designed in our laboratories. Three experimental models were used: xanthine/xanthine oxidase system, pulse radiolysis and experimental rat cancer (Yoshida Sarcoma) in vivo. In this work we measured the rate constant of the reactions of Metexyl with enzymatically generated O2.- or radiolytically produced .OH. For comparison, the reactions of non radical derivative (4-acetamide-2,2,6,6-tetramethylpiperidinium acetate) or nitroxide Tempace (4-acetamide-2,2,6,6-tetramethylpiperidine-1-oxyl) with the above mentioned reactive oxygen radicals were also studied. The comparative ability of Metexyl to act as an inducer of apoptosis in vivo was also investigated in pharmacological test. The ring substituent (-OCH3) at position 4 of the Metexyl molecule had significant influence on its properties as antioxidant and apoptosis inducer. The results in this study suggest that Metexyl is a promising nitroxide antioxidant, which can induce apoptosis of tumor cells in vivo, thus providing a base for its further investigations in vitro and pharmacological applications.

Animals↗
PubMedDate not supplied

Evidence for peroxidative oxidation of substituted piperidine nitroxides, acting as apoptosis inducers in Yoshida Sarcoma cells in vivo.

The results presented herein clearly indicate that nitroxide derivatives--free radicals are effective as substrates for one-electron oxidation in the peroxidase cycle involving hydrogen peroxide, which have been the subject of considerable controversy. This oxidation is catalyzed enzymatically and it might occur in tumor cells (in vivo) where the level of ROS (H2O2 and O2.-) is increased. The result of this reaction involving hydrogen peroxide is the obligative formation of the oxo-ammonium cation involved in the superoxide dismutase-mimic reaction of nitroxides with superoxide and/or in reaction with H2O2 leading to superoxide formation and regeneration of the parent nitroxide molecule. The efficiency of this enzymatically catalyzed oxidation of nitroxide(s) depends on the structure of the substituent in position 4 of nitroxide ring as follows: -OCH3 > -NHCOCH3 > -NHCOCH2CH3. Notably, the reduced nitroxide salt was not substrate for peroxidatic oxidation clearly indicating the importance of the free radical moiety of the nitroxide molecule. These findings may have some relevance in the recent investigations of antioxidant properties/mechanisms of nitroxides. Based on these considerations we hypothesize that the administration of oxidizable free radical nitroxide compounds--antioxidants may be a useful strategy in the treatment and investigations of cancer diseases. An in vivo study ("Screening test of chemicals employing Yoshida Sarcoma animals") was carried out to verify whether the structure and/or the chain length of substituent of oxidizable nitroxide derivatives--antioxidants could influence their apoptotic activity. The results reported in this study are encouraging as we found a limited correlation between the molecular oxidative properties of nitroxides under study, their structure and antitumor (apoptotic) action. In conclusion, this work demonstrates that investigation of the structure-dependent oxidation of antioxidatively acting nitroxides can become a very important step in their future screening and selection for applications in vivo and in vitro.

Animals↗
PubMedDate not supplied

The paradoxical apoptotic effects of novel nitroxide antioxidants on Yoshida sarcoma cells in vivo: a commentary.

Here we show for the first time that the model nitroxide derivatives, free radical or its reduced piperidinium salt, suppressed cytotoxicity of ROS (O2 and H2O2) generated outside the cells (B14 line, model for neoplastic phenotype) in ***. The nitroxides prevented the decrease in the number of *** caused by exogenous O2- and H2O2 at concentrations which were not themselves cytotoxic. In the present study, we have also shown that a very substantial difference in the cell response occurred when the model rat tumor cells (Yoshida Sarcoma ascites) were treated in vivo with six novel synthesized nitroxide antioxidants. A number of tumor cells displayed morphological characteristics of apoptosis. This effect was comparable to those observed for other nitroxyls under similar experimental conditions. Since the increase in the ROS generation followed by apoptotic changes of nuclei is the consistent recent finding in various experimental models of apoptosis, one fundamental question was raised: why nitroxide antioxidants paradoxically act as apoptosis inducers in vivo? Taking together the results presented here and in our previous works, it seems reasonable to suggest that nitroxide-antioxidants improve the endogenous "antioxidants reserve" and action can induce a reductive stress as opposed to an oxidative stress, triggering a cascade of dose-dependent processes involving indirectly an antioxidant mechanism(s) and resulting in the apoptotic death of cancer cells in vivo. The SAR (structure activity relationship) revealed that either the substituent structure at 4-position of the nitroxide ring or its oxidation state are determinant for the degree of the observed differences in the apoptotic potency of nitroxide derivates in vivo.

Animals↗
PubMedDate not supplied

Microgenia as a factor making endotracheal intubation impossible.

The authors report a case of microgenia which made endotracheal intubation impossible in a patient with pharyngeal stenosis. It is suggested that laryngological examination should precede the operation and when endotracheal intubation is impossible tracheostomy should be performed.

Adult↗