Biomedical subjects

V F Chekhun

Publications and source records attributed to V F Chekhun.

22 records · Page 2Linked to original sources

PubMedDate not supplied

[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.

Animals↗

PubMedDate not supplied

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.

Aging↗

PubMedDate not supplied

[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.

Animals↗

PubMedDate not supplied

[Treatment of patients with B-small cell lymphoma using R-CHOP protocol].

Non-Hodgkin's lymphoma is one of the most challenging problems in modern oncology. Creation of drugs inhibiting specifically intracellular signal tracks which being activated in its turn lead to oncogenes hyperexpression and inactivating other genes responsible for suppression of oncogenes, leading eventually to a cell's constant proliferation. This method is a new approach for cancer treatment. Nowadays homogeneous antibodies are widely used against superficial lymphocyte antigens. Rituximab is an anti-CD20 antibody fixed on the surface of malignant cells of most B-small cell lymphomas. In the department of systematic tumors at the institute of oncology of Medical Academy of Sciences a patient with large diffuse B-cell lymphomas had received Rituximab treatment. After the treatment, laboratory data and clinical investigation of the patient showed no signs of the disease. The patient was under observation at the institute of oncology of Medical Academy of Sciences over one year and found clinically, and according to its laboratory data, in a stable remission state.

Antibodies, Monoclonal↗