Assessment of the cyto- and genotoxic effects of a nanoferromagnetic and a static magnetic field in vivo

The cyto- and genotoxic effects of ferromagnetic nanoparticles (FNs), a static magnetic field (SMF), or their combination were comparatively studied in Ehrlich ascites carcinoma (EAC) cells, bone marrow (BM) erythroid series cells, and peripheral blood lymphocytes at definite time intervals, using the MN test and the DNA-comet assay. The MN test and the DNA-comet assay were used as markers of genotoxic exposure. It has been shown that the limit value of insignificantly expressed changes in the EAC cell architectonics (due to FNs) is an FN concentration of 3 mg/kg. The FN concentration increases in tumor cells, because the expressed blebbing in the cytoplasmic membrane increases the amount of micronuclei and the percentage of DNA in the comet tail in EAC cells, BM erythroid series cells, and peripheral blood lymphocytes. It has also been demonstrated that an SMF alone, as an independent factor, does not produce cytogenotoxic effects on the studied cells. When SMF and FN were used in combination, we could observe the phenomenon of SMF induction by FNs, which manifested itself as an increased total effect of these factors on cells. The MN-test and the DNA-comet assay can be used for assessing the genomic stability of both tumor cells and somatic nonmalignized cells when testing the genotoxic effect of nanomaterials used in the design of vector systems. As was established, the DNA-comet method demonstrated a higher sensitivity in the assessment of the genotoxicity produced by the studied factors.     

Phospholipid and cholesterol levels in the tumor cell plasma membranes with different sensitivity to doxorubicin

The investigation is aimed to study qualitative and quantitative composition of phospholipids, cholesterol content and lipids unsaturation index in plasma membranes of Guerin's carcinoma cells sensitive or resistant to doxorubicin. The comparison of infrared spectra and phospholipids unsaturation index showed that the unsaturation level of fatty acids in plasma membrane from resistant cells was lower than that from sensitive carcinoma cells. 31P-NMR spectroscopy of plasma membranes phospholipids shows the increase of phosphatidylserine and sphingomyeline content in plasma membrane isolated from resistant tumor as compared with sensitive tumor. The levels of phosphatidylcholine and phosphatidylethanolamine were equal in drug-resistant and drug-sensitive carcinoma strains. Changes in plasma membrane from resistant cells result in elevation of plasma membrane microviscosity and phosphatidylserine level increase can suggest the activation of P-glycoprotein-mediated efflux of doxorubicin.     

Ultrastructural organization of carcinoma Lewis (3LL) cells during cisplatin resistance formation

The electron-microscopic analysis of the morphological status of 3LL (Lewis) carcinoma tumour cells in the process of cisplatin resistant phenotype formation has been performed. It was shown that selection of tumour cells forming cell clones characterized by more complicated nuclear and cytoplasm organization took place. The tumour cells had the diffused nuclear chromatin; nuclear envelope had the numerous pores with expanded diaphragms. The prominent nucleoli consisted of the active centres surrounded by considerable areas of the condensed nucleolar chromatin. Cell cytoplasm contained the well-developed Goldgi complex and the numerous well-structured myelinoid formations in the form of dense-wrapped concentric membrane structures. The obtained data can morphologically confirm the hypothesis of Gately D.P. and Howel S.B., 1993, thain the process of resistant phenotype formation the tumour cells can create the cellular mechanisms to remove the drug from the cell and to correct the damages of the cellular nucleus and cytoplasm.     

Evaluation of the genome stability and mitochondrial potential of tumor cells in vivo under the action of nanoferromagnetics with different sizes of nanoparticles

The transmembrane potential and genome stability of tumor cells under nanoferromagnetic action with different sizes of nanoparticles were studied in vivo. An evaluation of the genotoxic influence of nanoeferromagnetics on tumor cells and changes in their mitochondrial potential was carried out with the application of a micronuclei test and mitochondrial fluorescent probe JC-1. Nanoferromagnetics with nanoparticle diameters of 40 and 100 nm at a concentration of 3 mg/kg were not found to deminish the trasmembrane mitochondrial potential and the genome of tumor cells and increase the micronucleus frequency of tumor cells to only a small extent. Iron nanoparticles at a concentration of 6 mg/kg were noted to demonstrate an antidromonous character of the changing mitochondrial potential and micronuclei frequency depending on their size. Iron nanoparticles with a smaller diameter were found to provoke an essential rise in the transmembrane potential of tumor cell metachondria on the background of a constant number of micronuclei, and the opposite was true for those with a greater diameter. The data obtained can serve as an important criterion for further studies in experimental oncology to create an optimal system for delivering anticancer preparations to tissue targets.     

Visualization of iron nanoparticles accumulation and distribution features in sensitive and resistant to antitumor drugs human breast cancer cells after different time intervals of cultivation with liposomal ferromagnetic

It was shown in vitro that visualization of iron nanoparticles by histochemical Lilly method, modified by authors for cytomorphological studies, could be a certain control of ferromagnetic income to human breast cancer MCF-7 cells with different sensitivity to antitumor drugs (doxorubicin and cisplatin). The form of the visualized iron nanoparticles, their localization and distribution towards intracellular structures was studied. It was shown that localization, dynamics of accumulation and release of ferromagnetic from cells were connected to their sensitivity to antitumor drugs and time of incubation with iron nanoparticles.     

Visualization of the features of the distribution and accumulation of iron nanoparticles in human breast cancer cells sensitive and resistant to antitumor drugs after cultivation with liposomal ferromagnetic during various time intervals

MCF-7 human breast cancer cells sensitive and resistant to cisplatin and doxorubicin were used in experiments. Various cultivation times of these cells in the presence of iron nanoparticles were used for the study. The potentialities of light optical visualization and also the peculiarities of the distribution, localization, and the dynamics of the accumulation of the liposomal form of ferromagnetic in cells have been studied. Based on an analysis of the data obtained in the experiments, we supposed that the most possible route for the inflow of iron nanoparticles into the examined cells is receptor mediated endocytosis, because after a 24-h incubation period, the incorporated iron is in the shape of separated granules localized near the cytoplasmic membrane. In addition, after 24 and 48 hours of cultivation, we discovered an increase in the number of ironpositive cells, as well as an increase in the percentage of tumor cells with a high ferromagnetic content due to the formation of dense structures characterized by cytoplasmic and perinuclear localization. It has been proved that the dynamics of the ferromagnetic accumulation and release from the cells are connected with their resistance to antitumor drugs and with their cultivation time in the presence of iron nanoparticles.     

Influence of tumor drug resistance phenotype on the dynamics of cisplatin-induced changes of rat peripheral lymphocyte chromatin structure in Guerin's carcinoma

The correlation between the tumor drug sensitivity and the degree of lymphocyte interphase nuclei chromatin damages induced by cisplatin in rats was found using sensitive and resistant to cisplatin variants of Guerin's carcinoma. Increased optical density of lymphocyte chromatin in first minutes after cisplatin injection both in rats without Guerin's carcinoma and with sensitive to cisplatin variants of this tumor was observed. Lymphocyte chromatin structure remains unchanged in rats with cisplatin resistant carcinoma. Normal blood cells are suppose to change their sensitiveness to cisplatin under the humoral influence of the growing tumor in according with its phenotype.     

Complex Growth Regulator Increases Alfalfa Seed Production

The effects of thermophilic methane fermentation products on alfalfa (Medicago sativa L.) growth, nitrogen-fixing activity, and seed production were studied in pot and field experiments. Plant treatment with the preparation at the stages of stooling and flower bud formation resulted in an increase in the root nodule weight and their nitrogen-fixing activity, the accumulation of cytokinins (zeatin and zeatin riboside), and an increase in the green mass yield and protein content, especially at a low (0.25 of the full rate) mineral nitrogen rate. Crop seed production was considerably improved during the first (pot experiments) and second (field experiments) growing seasons. The conclusion was drawn that the causes for improved alfalfa seed production were the effects of group B vitamins, phytohormones, their interaction, and the switching of metabolic pathways toward cytokinin synthesis.     

Age-related effects of methionine-enriched diet on plasma homocysteine concentration and methylation of hepatic DNA in rats

In the present study we determined the age-related effect of methionine-enriched diet, a model of hyperhomocysteinemia, on the level of plasma homocysteine and hepatic global DNA methylation in rats. Feeding methionine diet to middle-aged rats for only 14 days resulted in a significant increase in plasma homocysteine level and DNA hypomethylation. In contrast, feeding the methionine-containing diet for 2 weeks to juvenile or post-pubertal animals did not alter the level of plasma homocysteine or hepatic DNA methylation. Supplementation of the methionine-enriched diet with vitamins B6, B12 and folic acid prevented both hepatic DNA hypomethylation and an increase of plasma homocysteine concentration in the middle-aged rats. These findings indicate that the elevated level of plasma homocysteine may be indicative of much broader and deeper alterations in intracellular methylation dysfunction, and suggest that dietary enrichment with B-vitamins is essential for the metabolism of homocysteine, especially in adult animals.