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Biomedical subjects

J Polónyi

Publications and source records attributed to J Polónyi.

At least 19 recordsLinked to original sources
PubMed1998

The effect of flavonoids on ofloxacin-induced mutagenicity in Euglena gracilis.

The antimutagenicity of 14 naturally occurring flavonoids (20 mumol/l) on ofloxacin (43 mumol/l and 86 mumol/l)-induced bleaching (mutagenicity) was studied in Euglena gracilis. The flavonoids chrysin, techtochrysin, chrysin-5-methylether galangin, galangin-5-methylether, pinocembrin and pinobanksin possess considerable antimutagenic properties against ofloxacin-induced bleaching of E. gracilis. Apigenin and isalpinin had only weak antimutagenic potency. Pinobanksin-5-methylether and pinobanksin-3-acetate showed very weak or no antimutagenic effect. However, kempferol, quercetin-3-methylether and quercetin-3,3'-dimethylether showed co-mutagenic or no antimutagenic effect depending on the concentration of ofloxacin. Two possible modes of action of the flavonoids on ofloxacin-induced bleaching of E. gracilis are discussed.

Animals↗
PubMed1997

Influence of tetracyclines or cetylpyridinium bromide on activity of fluoroquinolones in Euglena gracilis.

To verify the hypothesis that the fluoroquinolone inhibitors of DNA gyrase generate some oxidant species and subsequently free radicals, the effects of simultaneous action of fluoroquinolones (ofloxacin, fleroxacin) and tetracyclines (tetracycline, doxycycline, thiatetracycline) or cetylpyridinium bromide as possible antioxidants on the flagellate Euglena gracilis were examined. Chloroplasts due to their bacterial character were injured and subsequently eliminated by fluoroquinolone. The loss of chloroplasts was accompanied by bleaching of originally green euglena cells. Tetracyclines, as well as cetylpyridinium bromide, decreased the euglena bleaching caused by ofloxacin or fleroxacin. The bleaching induced by ofloxacin or fleroxacin was most effectively inhibited by thiatetracycline and cetylpyridinium bromide. Control treating of cells with tetracyclines or cetylpyridinium bromide alone did not exert any bleaching effect. In vitro weak but significant interactions between examined substances were established as well.

Animals↗
PubMed1996

Antimutagens reduce ofloxacin-induced bleaching in Euglena gracilis.

The genotoxic effect of ofloxacin was significantly decreased by standard antimutagens (sodium selenite, ascorbic acid, butylated hydroxyanisole and butylated hydroxytoluene) in the unicellular flagellate Euglena gracilis. The antiofloxacin activity of sodium selenite was also documented by a bacterial test in which the repair-proficient strain Salmonella typhimurium TA102 was used.

Animals↗
PubMed1996

Tetracycline reduces fluoroquinolones-induced bleaching of Euglena gracilis.

Inhibitory activity of tetracycline against ofloxacin- and fleroxacin-induced bleaching of green and etiolated Euglena gracilis was examined. Tetracycline hydrochloride in concentrations of 83-2079 microM in the light partially inhibited the bleaching activity of 83 microM ofloxacin and of 162 microM fleroxacin. In the dark, the TC inhibition of the fluoroquinolones-induced bleaching activity was most obvious, the white colony counts were all decreased. The total inhibition of bleaching was observed in 43 microM ofloxacin and 81 microM fleroxacin both in light and darkness. Cell growth was not significantly influenced by ofloxacin, fleroxacin and tetracycline in the light or darkness. Cell growth was not significantly influenced by ofloxacin, fleroxacin and tetracycline in the light or darkness. Inhibition of ofloxacin-induced Euglena bleaching by tetracycline was more effective in etiolated cells. TC at 0-416 microM did not influence the growth of ofloxacin (2.15 microM)-induced Salmonella typhimurium revertants.

Animals↗
PubMed1993

Influence of ofloxacin on chloroplasts and mitochondria in Euglena gracilis.

Ofloxacin (CAS 83380-47-6), a representative of new quinolones, which exerts inhibitory activity against DNA gyrase in bacteria, damages both semiautonomous organelles in Euglena gracilis: chloroplasts and partly mitochondria. The action of ofloxacin on these organelles was analysed by transmission electron microscopy. The first symptoms of ofloxacin treatment were mass aberrations of chloroplasts with subsequent diluting out of these pathological organelles from the cells, so giving rise to the heterotrophic mutants. The loss of chloroplasts is hereditary. Changes in ultrastructure of mitochondria were observed too. Cup-like (in sections ring-like) mitochondria represented the most frequent abnormalities of these organelles induced by the drug. After repeated subcultivations on ofloxacin-free media the number of damaged mitochondria gradually decreased to the normal.

Animals↗
PubMed1992

[The ultrastructure of accumulated mitochondria in injuries of demyelinated axons].

The authors ligated the nervus lienalis of the cat, and observed the subsequent accumulation of mitochondria in nonmyelinated axons in close vicinity proximal and distal to the ligature. In enlarged axons they found groups of mostly homogen population of mitochondria with specific morphologic signs. Concerning the mitochondrial ultrastructure authors arranged the mitochondria to three classes and five subclasses. The authors discuss the aim and function of mitochondrial accumulation in the injured nonmyelinated axon. Different directions of mitochondrial group's motion in axons was hypothetically assumed.

Animals↗
PubMed1990

Ultrastructural study of small granule containing (SGC) cells in the lower mesenteric ganglion in drug treated guinea-pigs.

Small granule containing cells (SGC or SIF cells) in the lower mesenteric ganglion of the guinea-pig were studied in control and experimental animals. After reserpine administration a decrease of dense population of granular vesicles was found. After injection of nialamide and dopamine to the animals in SGC cells significantly increased the number and density of granular vesicles. No real efferent synapses were found on SGC cell processes, although sites with accumulated synaptic-like vesicles, mostly with a dense core, were often observed.

Animals↗
PubMed1990

Injured mitochondria in cells of Euglena gracilis after DNA gyrase inhibitors treatment.

Five quinolone (ofloxacin, cinoxacin, enoxacin, ciprofloxacin, oxolinic acid) and one non-quinolone (coumermycin A1) inhibitors of prokaryotic DNA gyrase used in clinical practice for treatment of bacterial infections were experimentally examinated. As model organism the flagellate Euglena gracilis was used. Ultrastructural changes in chloroplasts and mitochondria caused by inhibitors were quantitavely evaluated. Simultaneously in all cases injury and hereditary loss of chloroplasts (bleaching) were observed in the cells. In some samples about 45% of cup-shaped mitochondria cumulated in the cytoplasm. In damaged mitochondria some degenerative signs were seen, but after the last subcultivation on drug-free media the number of injured mitochondria in the bleached cells yielded to the normal value.

4-Quinolones↗
PubMed1989

Quinolones and coumarins eliminate chloroplasts from Euglena gracilis.

Quinolones and coumarins were potent eliminators of chloroplasts from Euglena gracilis. There was a remarkable similarity between antichloroplastic and antibacterial activities of DNA gyrase inhibitors. Quinolones produced 100% chloroplast-free cells in concentrations which do not affect cell viability. Optimal conditions were exponential growth, continuous illumination, and neutral or slightly alkaline pH. Coumarins were more toxic than quinolones. Among the quinolones, ofloxacin was the most potent in eliminating chloroplasts. Among the coumarins, coumermycin A1 was the most potent. New quinolones and coumermycin A1 were able to induce the complete inability of originally green cells to form green colonies after 24 h of drug exposure, while clorobiocin and novobiocin required several days of exposure. Darkness, heat shock (42 degrees C, 10 min), or simultaneous treatment with chloramphenicol or rifampin decreased the potency of DNA gyrase inhibitors for producing chloroplast-free cells. Remarkably, in cells in which division was blocked by three different methods (resting medium, hyperthermic conditions [37 degrees C], or addition of cycloheximide), new quinolones and coumermycin A1 nevertheless eliminated chloroplasts. The antichloroplastic activity of DNA gyrase inhibitors is additional data suggesting an evolutionary relationship between chloroplasts and eubacteria.

4-Quinolones↗
PubMed1989

[Reinnervation of the larynx in an experiment].

In an experiment on five dogs the authors investigated the topographic anatomical relations of the laryngeal recurrent nerve, the vagus, the phrenic nerve and ansa cervicalis. They elaborated a surgical approach to the above nerves. In nine dogs the authors dissected the n. laryngeus recurrens and made anastomoses: an end-to-end anastomosis in three dogs, a bypass anastomosis of the distal stump of the recurrent laryngeal nerve with a separated portion of the trunk of the vagus in two dogs, an end-to-end anastomosis of the distal stump of the recurrent laryngeal nerve with the dissected central portion of the phrenic nerve in four dogs (in one also interposition of the nerve trunk from a small branch of the ansa cervicalis was made). Reaxonization was investigated by histological examination. Satisfactory functional results were achieved after anastomosis of the recurrent laryngeal nerve and the phrenic nerve. Less satisfactory results were obtained when a portion of the vagus was used and subsequent anastomosis of the distal stump of the recurrent laryngeal nerve nad finally after end-to-end anastomosis of the previously dissected recurrent laryngeal nerve.

Anastomosis, Surgical↗