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A S Saenko

Publications and source records attributed to A S Saenko.

At least 19 recordsLinked to original sources
PubMed2006

Effects of structural and "mixed" isomers of Glu-Trp dipeptide on normal hemopoietic stem cells.

We studied the effects of optical (dd-, ll-, dl-, and ld-dipeptides with alpha-bond, EW) structural isomers and cyclic (dd-, ll-, dl-, and ld-dipeptides with gamma-bond, iEW) analogs of Glu-Trp synthetic dipeptide on the population of normal hemopoietic stem cells. Dipeptides containing lGlu (lGlu-lTrp, lGlu-dTrp) injected to mice were inert towards committed bone marrow CFU-S; dGlu-containing dipeptides (dGlu-dTrp, dGlu-lTrp) inhibited the growth of CFU-S-8; and LiGlu-dTrp stimulated these cells. Inhibitory or stimulatory effects of optical and chemical isomers of Glu-Trp dipeptide are determined by optical orientation and nature of peptide bond of Glu residue. The effects of cyclic and mixed peptides towards colony formation are similar to those of the corresponding linear dipeptides.

Animals↗
PubMed2005

Effects of iEW synthetic peptide isomers on bone marrow colony-forming capacity in vivo.

Studies of cooperative effects of D- or L-isomers of iEW dipeptide and neuraminidase on the number of splenic CFU, comparison of the peptide effects on CD34+ cells and splenic CFU, and evaluation of the effects of iEW D- or L-isomers on parameters of T-cell activation showed that interactions of L-(iEW) and D-(iEW) with CD34+ surface receptors are realized through the same mechanism, while their different biological effects on hemopoietic precursor cells in vivo can be explained by their different influence on T-component of the microenvironment.

Animals↗
PubMed2002

[Use of thymodepressin for treating autoimmune cytopenia].

AIM: To study influence of thymodepressin on the course of autoimmune cytopenia. MATERIAL AND METHODS: Thymodepressin is a new synthetic hemoregulatory dipeptide (gamma-D-Glu-D-Trp). It was used for the treatment of 22 patients with autoimmune cytopenia. RESULTS: Hemoglobin levels were elevated in autoimmune hemolytic anemia and platelet levels were high in idiopathic thrombocytopenic purpura. A thymodepressin course resulted in a fall of total lymphocyte count and activated CD3+CD69+ lymphocytes. CONCLUSION: The above results, safety, absence of toxicity and allergenicity, parenteral and intranasal useability open perspectives for further studies of therapeutic action of thymodepressin as an immunodepressant in autoimmune processes.

Adult↗
PubMed2000

Determination of somatic mutant frequencies at glycophorin A and T-cell receptor loci for biodosimetry of acute and prolonged irradiation.

Somatic mutant frequencies at glycophorin A (GPA) and T-cell receptor (TCR) loci were assessed. The dependence of the GPA mutant frequency on doses of acute and prolonged irradiation was shown. In the case of acute irradiation the GPA mutant frequency displayed a three-fold greater dose-related increase as compared to prolonged irradiation. A dose-dependent increase in the TCR variant frequency was found only in a group of subjects with recent exposures. In Chernobyl clean-up workers the TCR mutant frequency was significantly higher than in control non-irradiated individuals.

Case-Control Studies↗
PubMed2000

[Investigation of fetal cells isolated from maternal blood by different methods].

This paper presents the results of investigation of the isolated from maternal blood by 4 different methods according to the optimized protocols. All women had male fetuses. The mononuclear cells with fetal erythroblasts were preisolated by using density-gradient centrifugation of the maternal blood in the Ficoll solution. Fetal cells were detected by FISH for Y-chromosomal sequences. The fetal cells were 2.1% by fluorescence activated cell sorting (FACS); 3.8% by magnetic field sorting, and 2.6% by two-stage density gradient precipitation. The fetal lymphocytes were investigated through air-cultivation of peripheral maternal lymphocytes. Their proportion was 3.9% in the culture samples. The findings lead to the conclusion that the new non-invasive approach is useful for prenatal diagnosis of chromosomal aneuploidies.

Aneuploidy↗
PubMed1999

[A noninvasive approach to studying fetal cells for prenatal diagnosis of chromosomal aneuploidies].

Fetal cells isolated from maternal peripheral blood during the second trimester of pregnancy were analyzed. Blood samples were centrifuged in a Ficoll-Paque gradient, the mononuclear cell fraction was isolated and stained with fluorescent monoclonal antibodies against glycophorine A (GPA + PE), transferrin (CD71 + FITC), and Hoechst 33342. Fluorescence-activated cell sorting (FACS) was conducted on a Vantage flow cytofluorimeter (Becton Dickinson). Fluorescence in situ hybridization (FISH) with Y chromosome-specific DNA probe revealed fetal cells that exhibited Y signal in all 20 blood samples obtained from women pregnant with healthy male fetuses. The concentration of these fetal cells averaged about 1.34% and ranged from 0.1 to 4.2% in different blood samples. In six cases, blood samples were obtained from pregnant women, in which prenatal cytogenetic analysis revealed various fetal aneuploidies. Using FISH with DNA probes specific for chromosomes X, 18, and 13/21, Fetal cells with chromosomal aberrations were detected in these six maternal blood samples at a concentration from 1.5 to 5.6% (on average 3.7%). These results indicate the possibility of a new noninvasive approach, which is safe for both mother and fetus when used for isolation of fetal cells from pregnant women's blood samples and prenatal diagnosis of a broad spectrum of fetal cell chromosomal aberrations.

Aneuploidy↗
PubMed1998

Determination of somatic mutant frequencies at glycophorin A and T-cell receptor loci for biodosimetry of prolonged irradiation.

PURPOSE: To determine the variant frequencies (VF) at glycophorin A (GPA) and T-cell receptor (TCR) loci in persons exposed to prolonged ionizing radiation at different doses and to assess the significance of the GPA and TCR assays for biodosimetry of prolonged irradiation. MATERIALS AND METHODS: The VF values were determined by means of flow cytometry in 120 persons exposed between 1968-1996. Most exposures were in Chernobyl clean-up workers in 1986-1987. RESULTS: A significant correlation was shown between the NO GPA variant cell frequency and dose (r = 0.61, p < 0.0001). The slope of the linear regression was 6.3 x 10(-6) NO mutant cells/Gy. Dose-dependent increase in the TCR VF was found in the group with recent exposures (slope 2.1 x 10(-4) variant cells/Gy, r = 0.75, p = 0.0002). In the Chernobyl clean up workers who received doses less than 0.25 Gy the TCR VF unlike the GPA VF was significantly higher than in the control non-irradiated individuals (p < 0.01 and p > 0.05 respectively). CONCLUSIONS: The GPA assay has limited potential to be used as a biodosimeter of prolonged irradiation, at least in dose interval up to 2.0 Gy. The TCR assay is likely to have greater potential in estimation of recent radiation exposure than the GPA assay.

Adult↗
PubMed1997

Natural hidden antibodies reacting with DNA or cardiolipin bind to thymocytes and evoke their death.

Both free and hidden natural antibodies to DNA or cardiolipin were obtained from immunoglobulins of a normal donor. The free antibodies reacting with DNA or cardiolipin were isolated by means of affinity chromatography. Antibodies occurring in an hidden state were disengaged from the depleted immunoglobulins by ion-exchange chromatography and were then affinity-isolated on DNA or cardiolipin sorbents. We used flow cytometry to study the ability of free and hidden antibodies to bind to rat thymocytes. Simultaneously, plasma membrane integrity was tested by propidium iodide (PI) exclusion. The hidden antibodies reacted with 65.2 +/- 10.9% of the thymocytes and caused a fast plasma membrane disruption. Cells (28.7 +/- 7.1%) were stained with PI after incubation with the hidden antibodies for 1 h. The free antibodies bound to a very small fraction of the thymocytes and did not evoke death as compared to control without antibodies. The possible reason for the observed effects is difference in reactivity of the free and hidden antibodies to phospholipids. While free antibodies reacted preferentially with phosphotidylcholine, hidden antibodies reacted with cardiolipin and phosphotidylserine.

Animals↗
PubMed1996

Prognostic significance of S-phase fraction detected by antithymidine antibodies in epidermoid cervix carcinomas.

PURPOSE: To assess the predictive value of pretreatment proliferative activity of epidermoid cervix carcinoma cells with respect to short- and long-term results of radiotherapy. METHODS AND MATERIALS: The proliferative activity of 25 epidermoid cervix carcinomas was evaluated as the immunofluorescent labeling index (LI) by rabbit antithymidine antibodies reacting specifically with single-stranded DNA of replication forks in S-phase cells. The short-term clinical outcome was estimated at 3-6 months after treatment by visual and palpatory examination. Three-year follow-up data were obtained through hospital charts and correspondence with referring physicians for only 19 patients. RESULTS: There was no statistically significant association between LI and such conventional prognostic factors as clinical stage. The LI value of cervix carcinomas was significantly associated with complete regression at 3-6 months after radiotherapy and 3-year disease-free survival. Complete regression at 3-6 months was observed in 87.5% patients with fast proliferating tumors (LI > 7.0%), and only in 41.2% patients with slowly proliferating tumors (p = 0.03). Probability of 3-year disease-free survival was 85.7% in patients with fast proliferating tumors and 50.0% in those with slowly proliferating tumors (p = 0.05). CONCLUSIONS: The immunofluorescent LI of epidermoid cervix carcinoma is able to provide prognostic information on short-term tumor response to radiotherapy and disease-free survival.

Adult↗
PubMed1991

[DNA replication in mammalian cells after the action of physical, chemical or biological factors. VI. The recovery of DNA synthesis in a culture of irradiated cells].

The kinetics of DNA synthesis restoration in cultured HeLa cells and in L-929 mouse fibroblasts irradiated by gamma-rays of 60Co with a dose of 10 Gy was studied. Early after irradiation the rate of DNA synthesis in HeLa cells measured with 3H-thymidine incorporation was seen to decrease. Two hours later the incorporation starts to increase to reach the control level 4 hours after irradiation and then becomes even higher than this level. The distribution of cells among phases of the cell cycle measured with flow cytometry undergoes changes. 4-6 hours after irradiation part of S-phase cells increased contributing presumably to the elevating of 3H-thymidine incorporation observed at this time. The restoration of the incorporation was suppressed by inhibitors of protein and RNA synthesis--cycloheximide and actinomycin D. It is suggested that the processes of restoration of DNA synthesis in irradiated cells can be of inducible nature. In irradiated HeLa and L-929 cells the restoration of DNA synthesis is resistant to novobiocin, an inhibitor of DNA replication.

Animals↗
PubMed1990

Inducible processes in DNA replication and repair after gamma, UV-irradiation and action of some chemicals in mammalian cells.

Restored DNA synthesis in mammalian gamma-, UV-irradiation and action of FdUrd was shown to be resistant to gamma- and UV-irradiation or heating. This correlates well with changes in chromatin structure and perhaps depends on the modification of the latter. For studying possible inducible characteristics of restored process of DNA synthesis the irradiated cells were incubated with cycloheximide (1 or 10 micrograms ml-1) or actinomycin D (0.05 ug ml-1). It was shown that in the presence of cycloheximide or actinomycin D restoration of DNA synthesis did not occur. A high rate of postreplicative DNA repair in UV-irradiated HeLa cells occurs after the previous action of FdUrd or UV-irradiation. Under these conditions daughter DNA strands have few gaps. Two-dimensional gel electrophoresis of proteins from the cells with resistant DNA synthesis demonstrates higher level some of these and lower one of the other proteins.

Cycloheximide↗
PubMed1990

[Approaches to the individual prognosis of tumor reaction to radiation and drug exposures].

The problem in individual prediction can be viewed in two aspects: 1. to define the nature of tumor response to antitumor therapy; 2. to determine whether a specific therapeutic method is sufficient for a patient's cure. Individual prediction cannot solve the problem of therapy of cancer patients, however it will noticeably improve the results of routine cancer therapy and will help to use correctly uncommon therapeutic methods. The choice of patients with radioresistant malignant tumors out of the whole population will enable one to select correctly radiomodifiers.

Antineoplastic Agents↗
PubMed1987

Effect of fluorodeoxyuridine on the sedimentation of nucleoids from HeLa cells in sucrose gradients.

Sedimentation properties of nucleoids from HeLa cells cultured for 6 or 24 h with 10(-6) M fluorodeoxyuridine (FdUrd) were studied in neutral sucrose gradients. Independently on the presence and concentrations of ethidium bromide in the gradient, nucleoids from FdUrd treated cells sedimented farther than those from untreated cells. However, the maximum relaxation of supercoiled DNA, observed at the concentration of 5 micrograms/ml of ethidium bromide, was significantly lower in cells treated with FdUrd, which indicated that prior incubation with FdUrd did not increase the degree of DNA supercoiling but altered by some way the conformation of DNA in nucleus. Previously we have found, that treatment of HeLa cells with FdUrd resulted in the stimulation of DNA synthesis, which proved to be resistant to ultraviolet and gamma-irradiation. From the present results it is possible to suggest, that alterations of chromatine structure should be included in facilitating of DNA synthesis on DNA template damaged by ultraviolet or gamma irradiation.

Cell Nucleus↗
PubMed1986

[The role of phosphoric acid residues in the formation of antigenic determinants of the structural components of DNA].

The inhibitory activity of thymidine, thymidine triphosphate and thymidyl oligonucleotides was studied in thymidine-antithymidine antibodies reaction. Thymidine was shown to have the greatest inhibitory effect, with thymidine triphosphate and thymidyl oligonucleotide inhibitory activity less expressed and reducing with the increase in oligonucleotide length. The effect of thymidine, thymidine triphosphate and thymidyl oligonucleotides on the interaction of antisera and SLE patients' sera with denatured DNA was studied. It was shown that thymidine triphosphate and particularly thymidyl oligonucleotides are characterized by greater inhibitory capacity, as compared to thymidine. It was found that only thymine dimers bound by phosphate groups can inhibit the interaction of UV-irradiated DNA with antiserum specific for UV-modified DNA. The data obtained suggest that the charge determined by phosphoric acid residues plays an essential role in the interaction of antibodies induced to charged structural DNA components.

Antibodies, Antinuclear↗
PubMed1986

[DNA replication in mammalian cells after the action of factors of a physical, chemical or biological nature. V. The structural reorganization of replicating DNA in HeLa cells after incubation with 5-fluorodeoxyuridine].

A study was made of sedimentation properties of the nucleoid (chromatin) of HeLa cells with radio- and thermostable mode of DNA synthesis induced by 5-fluorodeoxyuridine (FUdR). After the incubation of HeLa cells with FUdR (10(-6) M, 6 h or 24 h) the rate of nucleoid sedimentation was shown to rise by 40 and 25%, respectively. Maximum relaxation of the nucleoid was observed under 5 mg/ml ethidium bromide concentration in sucrose gradients. After the incubation with FUdR the nucleoid relaxes to a lesser extent, and after irradiation its response to ethidium bromide in various concentrations was similar to that of intact nucleoid, and by this property the "FUdR nucleoid" differs essentially from the irradiated "normal nucleoid". A model of chromatin structure of cells exposed to FUdR is proposed, based on the transformation of large domains in small ones, for the explanation of radioresistant DNA synthesis.

Cell Cycle↗
PubMed1985

[DNA replication in mammalian cells after exposure to factors of a physical, chemical or biological nature. III. 5-Fluorodeoxyuridine induces DNA synthesis in cells not suppressed by gamma irradiation].

The influence of preincubation of HeLa and Chinese hamster V79 cells with fluorodeoxyuridine (FUdR, 10(-6) M) on DNA replication and molecular weight of nascent DNA was studied after gamma-irradiation with a dose as much as 10 Gy. The 60Co-radiation inhibits DNA synthesis in both HeLa and V79 cells by 30-40 per cent. The incubation with FUdR before irradiation suppresses the inhibitory effect of irradiation on DNA synthesis. It is suggested that differences in gamma-radiation inhibition of DNA synthesis may result from the FUdR-induced changes in chromatin structure, rather than from synchronization of cell growth. This suggestion is based on the observation that the radioresistant mode of DNA synthesis occurred 18 hours following the short-term (6 hours) incubation with FUdR in cell cultures differing from each other in almost 2-fold their cell longevity.

Animals↗