Biomedical subjects

E Rudolf

Publications and source records attributed to E Rudolf.

13 recordsLinked to original sources

PubMed2005

Protective effect of S-adenosylmethionine against galactosamine-induced injury of rat hepatocytes in primary culture.

The protective effect of S-adenosylmethionine (SAMe) on D-galactosamine (GalN)-induced damage to rat hepatocytes was tested in primary cultures. SAMe at concentrations of 50 and 1000 mg/l significantly reduced lactate dehydrogenase release from cells injured by 40 mM GalN after 24 h of incubation. There were no significant changes in urea production after 24 h among tested groups, including control hepatocytes. Exposure of hepatocytes to GalN leads to 3.5-fold decrease in urea synthesis after 48 h in comparison with control cell cultures. Addition of the highest dose of SAMe (1000 mg/l) into the culture media attenuated this decrease by 180 %. None of the tested doses of SAMe (5, 25, 50 and 1000 mg/l) affected considerably the reduced activity of mitochondrial dehydrogenases. The content of reduced and oxidized glutathione in GalN-exposed cells was diminished to 1.5 % and 16 %, respectively, of the control values after 24 h. Using only the highest concentration SAMe increased significantly these contents. SAMe had no effect on dramatically decreased albumin synthesis. These findings indicate beneficial effect of SAMe, especially of the highest concentration, on GalN-induced toxicity to rat hepatocytes in primary culture. This action of SAMe seems to be associated with reduction of plasma membrane damage and increased synthesis of glutathione.

Animals↗

PubMed2004

Sodium salicylate inhibits NF-kappaB and induces apoptosis in PC12 cells.

Sodium salicylate (NaSal) is an effective analgetic and antiinflammatory drug. Beside its well-known inhibitory effect on the cyclooxigenase enzymes, it influences the activity of other signal transduction proteins including nuclear factor kappa B (NF-kappaB) transcription factor. NF-kappaB is found in the cytoplasm bound to an inhibitory protein, inhibitory kappa B (IkappaB). After its phosphorylation, IkappaB is degraded and the released NF-kappaB translocates into the nucleus. Sodium salicylate inhibits the degradation of IkappaB, thus, NF-kappaB activation cannot occur. According to previous observations, the inhibition of this activation can lead to apoptosis. The main goals of this study were to demonstrate that inhibition of NF-kappaB by sodium salicylate decreases the viability of rat phaeochromocytoma PC12 cells and to investigate the nature of cell damage and death. PC12 cells were treated with different concentrations of sodium salicylate (1-20 mM). Higher concentrations (10-20 mM) killed PC12 cells in a dose-dependent manner. The assessments were done by direct cell counting in a Burker chamber and by the WST-1 cytotoxicity assay. We also found a decreased NF-kappaB activity after sodium salicylate treatment by electrophoretic mobility shift assay (EMSA). The cells treated with sodium salicylate were undergoing apoptosis as seen on our records obtained by time-lapse videomicroscopy as well as shown by DNA fragmentation experiments. The decreased DNA binding activity of NF-kappaB indicates that the inhibition of NF-kappaB can play a role in these processes.

Animals↗

PubMed2004

Combined effect of sodium selenite and campthotecin on cervical carcinoma cells.

The effects of selenite, campthotecin and their combination were investigated in cervical carcinoma cell line Hep-2 HeLa during 24h. The measured parameters included morphological changes, proliferation, oxidative stress, mitochondrial status, caspase-3 activation and nuclear fragmentation. Selenite at all but lowest concentrations inhibited cell growth and proliferation and induced cell death characterized by membrane blebbing, oxidative stress and mitochondrial damage, occurring in the absence of caspase-3 activation and nuclear fragmentation. Campthotecin at all concentrations induced gradual apoptosis including all measured morphological and molecular parameters with exception of oxidative stress. A combination of selenite and campthotecin induced both antagonistic and synergistic effects on cervical carcinoma cells. While low selenium concentration slightly reduced cytotoxicity and proapoptotic effects of campthotecin, moderate and higher concentrations of selenium enhanced them, changing simultaneously apoptosis into more necrosis-like death. These results show importance of selenium as a potential modulator and enhancer of campthotecin-based anticancer therapy in nonovarian malignancies.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

Topoisomerases and tubulin inhibitors: a promising combination for cancer treatment.

Modern approaches to treatment of cancer seek to activate the internal suicide program in the malignant cells, and thereby effectively eliminate them without engaging most of other bodily systems. Many currently used cytostatics are known to induce apoptosis and efforts are being paid to develop new ones with better and more effective proapoptotic potential. Nevertheless, despite recent developments in this field, there are still numerous malignancies showing a varying degree of resistance to cell death due to the corrupted signaling pathways and genetic alterations, often in conjunction with expansive proliferation rate. It has been shown that topoisomerase inhibiting agents such as etoposide, camptothecin and others represent a powerful and dynamic group of cytostatic chemicals used in experimental and clinical conditions. So, it is a group of microtubule targeting poisons comprising classical colchicines on the one hand and new taxanes on the other hand. Since several members of both groups have been evidenced as apoptosis inducers operating via distinct mechanism, their combination should theoretically enhance the final therapeutic outcome. This minireview focuses on the possibilities of such a combinational approach with respect to possible benefits and hazards of this strategy.

Antineoplastic Agents↗

PubMed2002

3D-computer based reconstructions of apoptotic nuclei.

We present a 3D-model of apoptotic nuclei of HL-60 cells treated with 10 g/ml Etoposide (topoisomerase II inhibitor) for 24 hours. The static model was generated from a series of optical sections obtained through a confocal microscope by freeware and shareware graphical programs available in the Internet. Its animation was done by 3D Studio Max. We demonstrate the appearance of typical fragmentation and condensation of chromatin accompanied by its aggregation to the inner side of the nuclear membrane.

Apoptosis↗

PubMed2001

[Zinc and its role in the regulation of cell death].

Zinc is a key element for maintenance of the structural and functional integrity of eukaryotic cells and tissues. In living systems, it forms stable complexes with macromolecules as well as so called labile pools called zincosomes, which are nowadays considered crucial for the regulation of apoptosis and cell proliferation. Zinc may block apoptosis induced by many external factors by inhibiting caspases and endonucleases, through interactions with transcription factors and kinases or due to its antioxidant activities. On the other hand, depletion of zinc may lead to rapid activation of apoptotic cascade and consequent cell death in many types of cells. Imbalances in intracellular zinc pools lead to improper regulation of cell death and proliferation, which is often causing or accompanying diseases. Therefore, detailed elucidation of the role of zinc in these regulations presents a solution for various pathophysiological conditions.

Apoptosis↗

PubMed2000

Apoptosis - when the cells begin to dance.

We present a 24-hour time-lapse videosequence of in vitro behavior of Hep-2 cells treated with 10 m g/ml Etoposide, a topoisomerase II inhibitor. The cell behavior was recorded by a Mitsubishi video recorder, HS-S5600. In the presented sequence, we show the typical cell rounding accompanied by formation of numerous pseudopodia and rapid rhythmical contractions, so called membrane blebbing known as "dance of death".

Apoptosis↗

PubMed2000

The dynamics of the hexavalent chromium induced apoptotic patterns in vitro.

Although hexavalent chromium has been shown to induce apoptosis in cells cultivated in vitro, there appear to be no studies focusing on the dynamics of this process. To find out about dynamic patterns of hexavalent chromium-induced apoptosis, we treated Hep2 cells with 150 micrograms/ml potassium chromate and recorded their behavior as well as appearance of some crucial organelles using different morphological and biochemical methods. We found that Hep2 cells showed the earliest observable changes at 6 hours after the treatment (blebbing, chromatin shrinkage), with the entire apoptotic process lasting up to 24 hours. While all the observed cell features clearly prove apoptosis induced by hexavalent chromium, a typical apoptotic hallmark, DNA ladder, seems not to occur in this type of cells. On the other hand, in HL60 cells, used as a control, this ladder was observable.

Apoptosis↗

PubMed1999

The role of mitochondria in apoptosis induced in vitro.

Cell death remains the focus of in vitro toxicology. Xenobiotics are capable of bringing about two types of cell death: apoptosis and necrosis. From our previous study we know that cells treated with xenobiotics showed very dynamic changes in their morphology, particularly vigorous movement of the plasma membrane. Such changes probably depend on adequate energy supply. This observation stands in contradiction with published data showing that generation of ATP in mitochondria is altered very early in apoptosis. In this study we analysed the relationship between mitochondrial activity and cell death induced by Etoposide, a selective inhibitor of topoisomerase II, treatment (10 microg/ml). As a model system we used stabilised cell line Hep2. Several markers of apoptosis, including typical cell morphology and DNA ladder formation were measured. The dynamics of morphological changes was recorded by the time-lapse videomicroscopy. We measured mitochondrial membrane potential with a specific fluorochrome DASPMI, quantification was done by microfluorometric assessment. Our data show that mitochondrial activity was maintained during the first 6 hours after the treatment with Etoposide, at the same time substantial changes in cell morphology as well as typical DNA fragmentation were observed.

Apoptosis↗

PubMed1998

[A review of findings on chromium toxicity].

Chromium belongs amongst highly industrially utilized elements. Its role, however, encompasses the physiologic function too. On the other hand, increased exposition to this element, either during its processing, production or in nature in a form of a toxic waste, can lead to the arising of the toxic effects. These toxic features of chromium have been in focus for many years and herein are given together with some new discoveries, such as the influence of chromium on apoptosis, or specific mutations in genes caused by chromium and their repair.

Animals↗

PubMed1997

Purification and partial characterization of peptidase-1, a sex-linked enzyme in Pleurodeles waltl (urodele amphibian).

Peptidase-1 is a sex-linked enzyme, which can be purified from the liver of the amphibian urodele Pleurodeles waltl. We estimated its apparent molecular mass as 170 kDa by gel filtration chromatography. The enzyme is composed of two subunits with apparent molecular masses of 90 and 99 kDa. It is strongly inhibited by ethylenediaminotetraacetic acid, ethylene glycol bis(beta-aminoethyl ether)-N,N-tetraacetic acid, and 1,10-phenanthroline, indicating that peptidase-1 is a metallopeptidase. Peptidase-1 has optimal activity at 55 degrees C and pH 8.5. This acidic enzyme displays two apparent isoelectric points, at 4.9 and 5.2, and is essentially located in the cytosolic subcellular fraction.

Animals↗

PubMed1996

Peptidase-1 expression in some organs of the salamander Pleurodeles waltl submitted to a 12-day space flight.

In Pleurodeles, the peptidase-1 is a sex-linked enzyme encoded by two codominant genes (Pep-1A and Pep-1B) located on the Z and W sex chromosomes. The sexual genotype can be determined by the electrophoretic pattern of the peptidase from erythrocytes. ZAWB genotypic females characterized by 3 electrophoretic bands AA, AB and BB were embarked on Cosmos 2229. The pattern in ovary, muscles and gut issued from the embarked or synchrone females displayed the 3 characteristic bands. In heart and kidney, the bands AA and AB [correction of BB] were revealed, while the band BB appeared very faintly. The specific enzymatic activity in the same organs was compared. Except for the kidney, no statistical significant difference was observed between flight and synchrone samples. This enzyme can be efficiently used as sexual genotypic marker of Pleurodeles experimentally submitted to the effects of space environment.

Animals↗

PubMedDate not supplied

Toxic effects of chromium acetate hydroxide on cells cultivated in vitro.

Many human activities, particularly industrial ones, result in an ever-growing production of toxic waste materials. The dynamics of the toxic effects of chromium acetate hydroxide, which is found in high concentrations in a waste sediment produced in the Czech Republic, were assessed by using a battery of in vitro tests carried out on two cell lines: L-929 (mouse fibroblasts) and Hep 2 (human laryngeal cells). Various markers of cell damage were assessed by phase-contrast, video and fluorescence microscopy, fluorometry, and DNA analysis. Chromium acetate hydroxide, over a concentration range of 1-0.02mol/l induced immediate cell death by fixation, whereas, at 0.002mol/l, the treated cells died in a much slower, more discrete manner. All the detected markers of cell damage, whether immediate or slow, clearly demonstrated that the cells died by necrosis. On the other hand, test concentration of 0.001mol/l appeared to constitute a threshold at which no pathological changes of Hep 2 cells were observed over 96 hours. We conclude that chromium acetate hydroxide has a high toxic potential in vitro, which should be considered when studying the toxicity of waste materials containing it.

Animals↗