PubMed Health⌕ Search

Biomedical subjects

D V Semenov

Publications and source records attributed to D V Semenov.

At least 19 recordsLinked to original sources
PubMed2006

[Effect of exogenous dna injection on leukopoietic repair and antitumor action of cyclophosphamide].

The cytostatic drug cyclophosphamide (CPA) in high dosage suppressed hemopoiesis by causing multiple double-strand breaks to occur in hemopoietic cell DNA and leading to mutation, chromosomal abberations and finally cell death. We tested fragmented DNA drugs for an ability of CPA to protect murine leukopoiesis on an assumption that once exogenous fragmented DNA had infiltrated into a cell, it might integrate with chromosomal DNA through homologous recombinations thus repairing damaged segments. DNA drugs did promote repair of leukocyte count in murine peripheral blood with leukopoiesis being suppressed by CPA administration. The levels of DNA derived from murine organs and human placenta were higher than those from salmon roe. Tumor growth was significantly inhibited following injection of placental DNA into mice bearing intramuscularly transplanted lymphosarcoma. Antitumor effect of combined CPA and DNA treatment was much higher than after CPA alone.

Animals↗
PubMed2004

Oligonucleosome DNA fragmentation of caspase 3 deficient MCF-7 cells in palmitate-induced apoptosis.

Oligonucleosomal fragmentation of nuclear DNA is the late stage hallmark of the apoptotic process. In mammalian apoptotic cells fragmentation is catalyzed by DFF40/ CAD DNase. DFF40/CAD primary activated through site-specific proteolytic cleavage by caspase 3. The absence of caspase 3 in MCF-7 leads to lack of oligonucleosomal DNA fragmentation under numerous apoptotic stimuli. In this study it was shown that palmitate induces apoptotic changes of nuclei and oligonucleosomal DNA fragmentation in casp3 deficient MCF-7. Activation and accumulation of 40-50 kDa DFF40 like DNases in nuclei and cytoplasm of palmitate-treated MCF-7 were detected by SDS-DNA-PAGE assay. Microsomes of apoptotic MCF-7 activate 40-50 kDa nucleases when incubated with human placental chromatin and induce oligonucleosomal fragmentation of chromatin in cell free system. Both DNases activation and chromatin fragmentation are suppressed in presence of caspase 3/7 inhibitor Ac-DEVD-CHO. Microsome associated caspase 7 is suggested to play the principal role in induction of oligonucleosomal DNA fragmentation of casp3 defitient MCF-7.

Animals↗
PubMed2003

Oligonucleosomal DNA fragmentation in MCF-7 cells undergoing palmitate-induced apoptosis.

Oligonucleosomal fragmentation of nuclear DNA is the late-stage apoptosis hallmark. In apoptotic mammalian cells the fragmentation is catalyzed by DFF40/CAD DNase primarily activated by caspase 3 through the site-specific proteolytic cleavage of DFF45/ICAD. A deletion in the casp3 gene of human breast adenocarcinoma MCF-7 results in lack of procaspase 3 in these cells. The absence of caspase 3 in MCF-7 leads to disability to activate oligonucleosomal DNA fragmentation in TNF-alpha induced cell death. In this study, sodium palmitate was used as an apoptotic stimulus for MCF-7. It has been shown that palmitate but not TNF-alpha induces both apoptotic changes in nuclei and oligonucleosomal DNA fragmentation in casp3-mutated MCF-7. Activation and accumulation of 40-50 kD DFF40-like DNases in nuclei of palmitate-treated apoptotic MCF-7 were detected by SDS-DNA-PAGE assay. Microsomal fraction of apoptotic MCF-7 does not contain any detectable DNases, but activates 40-50 kD nucleases when incubated with human placental chromatin. Furthermore, microsomes of apoptotic MCF-7 induce oligonucleosomal fragmentation of chromatin in a cell-free system. Both the activation of DNases and chromatin fragmentation are suppressed in the presence of the caspase 3/7 inhibitor Ac-DEVD-CHO. Microsome-associated caspase 7 is suggested to play an essential role in the induction of oligonucleosomal DNA fragmentation in casp3-deficient MCF-7 cells.

Apoptosis↗
PubMed2001

[Mycotic aneurysms of the thoraco-abdominal part of the aorta].

Mycotoc aneurysms (MA)--a rare and extremely dangerous lesion of the aorta. CT, MRA and aortography were used to diagnose MA of the thoracoabdominal areas in 2 men of 64 and 67 years of age. The clinical picture included: fever with shivering with the temperature 38-39 degrees C and increasing pains in the inferiothoracic and lumbar areas of the spine. Hemoculture was positive in 1 patient only. The patients were operated on. Shunting of the aorta from the inferiothoracic to infrarenal segments was performed in one patient with the exclusion of the involved portion and resection of MA. Metalloosteosynthesis of the spine due to destruction of LI-LII and compression of the spine were performed in the second patient followed by analogous shunting of the aorta and visceral arteries with the resection of the aneurysm. To prevent infection of the prostheses the shunts were wrapped up with a piece of the greater omentum. One patient died two months later from recurrent sepsis. The other one is alive, within 28 months the shunts are patent, there are no signs of a reinfection.

Aged↗
PubMed2000

Influence of nucleic acids and polysaccharides on phosphotransferase activity of preparations of secretory immunoglobulin A from human milk.

The influence of nucleic acids (DNA, tRNA), synthetic oligonucleotides, and polysaccharides (lipopolysaccharides from Escherichia coli, heparin) on protein kinase and lipid kinase activities of preparations of human secretory immunoglobulin A (sIgA) has been studied. The preparations of sIgA were isolated from human milk by chromatography on the column with Protein A-Sepharose and DEAE-sorbent (sIgA1), by affinity chromatography of sIgA1 on DNA-cellulose (sIgA2), and by gel-filtration of sIgA1 in buffer containing 5% dioxane (sIgA3). Two 32P-labeled products with high and low electrophoretic mobility in polyacrylamide gel containing SDS were found after incubation of sIgA1 and sIgA2 with [gamma-32P]ATP. The product with low electrophoretic mobility was degraded in 10% trichloroacetic acid giving a radioactive background in lanes of the polyacrylamide gel. 32P-Labeled phospholipids were found among the phosphorylation products. Soluble and immobilized DNA increase lipid kinase activity of preparations of sIgA. In this case the secretory component and H-chains of sIgA were degraded. Fractions possessing lipid kinase activity were precipitated in the presence of heparin (1 mg/ml), and lipid kinase activity was separated from sIgA by gel-filtration in buffer containing 5% dioxane. 32P-Labeled products were formed in the presence of [gamma-32P]ATP as well as [32P]ortho-phosphoric acid. The influence of heparin and synthetic deoxy- and ribooligonucleotides on casein kinase activity of sIgA3 was studied. It was observed that deoxyribooligonucleotides in micromolar concentrations increased the rate of casein phosphorylation in the presence of sIgA3 and [gamma-32P]ATP. It has been proposed that catalytically active sIgA have an affinity to DNA (anti-DNA sIgA) and can be present in human milk as a part of lipoprotein complexes.

Adenosine Triphosphate↗
PubMed1999

Human milk lactoferrin binds two DNA molecules with different affinities.

Evidence is presented that lactoferrin (LF), an Fe3+-binding glycoprotein, possesses two DNA-binding sites with different affinities for specific oligonucleotides (ODNs) (Kdl = 8 nM; Kd2 approximately 0.1 mM). The high affinity site became labeled after incubation with affinity probes for DNA-binding sites; like the antibacterial and polyanion-binding sites, this site was shown to be located in the N-terminal domain of LF. Interaction of heparin with the polyanion-binding site inhibits the binding of ODNs to both sites. These data suggest that the DNA-binding sites of LF coincide or overlap with the known polyanion and antimicrobial domains of the protein.

Anti-Infective Agents↗
PubMed1999

Human milk lactoferrin binds ATP and dissociates into monomers.

The physiological role of lactoferrin (LF) is still unclear, but it has been suggested to be responsible for primary defence against microbial infections. Many different unique functions have been attributed to LF, including DNA and RNA binding, and transport into the nucleus, where LF binds to specific DNA sequences and activates transcription. Here we present evidence that in addition to the above (and below) mentioned functions LF binds ATP with a stoichiometry of 1 mole of nucleotide per mole of the protein and a Kd = 0.3 mM. The ATP-binding site is localized in the C-terminal domain of LF, in contrast to the antibacterial and polyanion-binding sites, which are located in the N-terminal domain. Binding of ATP by LF leads to dissociation of its oligomeric forms and to a change of the protein's interaction with polysaccharides, DNA and proteins.

Adenosine Triphosphate↗
PubMed1999

Secretory immunoglobulins A from human milk possess affinity to oligonucleotides and nucleic acids.

The antibody (AB) fraction containing sIgA and IgG was isolated from human milk by Protein A-Sepharose chromatography and was shown to possess affinity to DNA-cellulose. Ion-exchange HPLC of these AB on a TSK DEAE-5PW column resulted in the isolation of a fraction containing sIgA and oligonucleotides (ON). Gel-filtration of the AB fraction revealed the presence of ON with length 4-8 nucleotides co-isolating with sIgA. sIgA Preparations purified on DEAE-Fractogel and DNA-cellulose contained lipids which were phosphorylated in the presence of [gamma-32P]ATP. The affinity of HPLC-purified IgG and sIgA to calf thymus DNA, Escherichia coli DNA and total tRNA, and plasmid DNA was demonstrated. IgG was shown to bind to thymus DNA and E. coli DNA, and sIgA was shown to bind to E. coli DNA and tRNA. Nucleic acids of intestinal microflora are supposed to participate in induction of the secretory immune response.

Antibody Affinity↗
PubMed1998

Catalytic DNA- and RNA-hydrolyzing antibodies from milk of healthy human mothers.

Various catalytically active antibodies (Abs), or abzymes, have been detected recently in the sera of patients with autoimmune pathologies, in whom their presence is probably associated with autoimmunization. Normal humans are generally not considered to have abzymes, since no obvious immunizing factors are present. Here is shown by different methods that IgG from the milk of normal females possesses both DNase and RNase activities. The activities were also present in the IgG F(ab')2 and Fab fragments. Affinity modification of IgG by the chemically reactive derivative of an oligonucleotide led to preferential modification of the L chain of IgG. After separation of the subunits by sodium dodecyl sulfate electrophoresis in a gel containing DNA, an in-gel assay showed DNase activity in the L chain. The L chain separated by affinity chromatography on DNA-cellulose was catalytically active. These findings speak in favor of the generation of catalytic Abs by the immune system of healthy mothers. It is known that the treatment of adults with DNases and RNases offers protection from viral and bacterial diseases. Since breast milk protects the infants from infections until the immune system is developed, this raises the possibility that catalytic Abs like nucleases, may possess a protective role.

Adult↗
PubMed1998

Secretory immunoglobulin A from human milk catalyzes milk protein phosphorylation.

This article presents evidence that protein kinase activity is an intrinsic property of secretory immunoglobulin A (sIgA) from milk of healthy human mothers. Polyclonal sIgA was purified by sequential chromatography on protein A-Sepharose, DEAE-cellulose, and gel filtration on Toyopearl HW-55 and Sepharose 4B columns. Its purity was established by one- and two-dimensional SDS-PAGE. The protein kinase activity was inhibited by specific antibodies (Abs) against sIgA, and was stable to acidic and alkaline conditions. Catalytic sIgA showed optimal reaction conditions (pH and MgCl2 concentration) and substrate specificity different from those of known protein kinases; i.e., sIgA phosphorylated the serine residues of various milk proteins in the presence of different gamma-[32P]nucleoside- and deoxynucleoside-5'-triphosphates. The homogeneous Fab fragment of sIgA also showed kinase activity. An ATP-binding activity of fractions of sIgA was demonstrated by affinity chromatography on ATP-Sepharose and by covalent binding of an affinity analog of ATP; this activity was mediated by the L chain of sIgA. The authors believe these observations are the first example of the catalytic activity of IgA Abs and of natural catalytic Abs with synthetic activity. In addition, the findings suggest the likelihood that catalytic Abs are generated by the immune system of healthy mothers.

Adult↗
PubMed1998

Phosphorylation of lipids tightly bound to secretory immunoglobulin A in antibody fractions from human breast milk possessing protein kinase activity.

The fractions of antibodies (Abs) containing only sIgA and IgG were purified from human breast milk by Protein A-Sepharose chromatography and they catalyzed phosphorylation of casein in the presence of [gamma-32P]ATP. Also, 32P-labeled low-molecular-weight non-protein products are formed which are visible as radioactive background on the polyacrylamide gel lanes during electrophoresis of Abs under denaturing conditions. Separation of sIgA from IgG using a DEAE-sorbent with subsequent gel-filtration in 0.05 M NaOH indicates that the low-molecular-weight substances partially remain tightly bound to sIgA and are separated only by gel-filtration in a buffer containing 5% dioxane (non-denaturing resolution) or by extraction of the sIgA pellet with the chloroform--methanol mixture (2:1). The 32P-labeled substances were separated by TLC in the system used for phospholipid chromatography forming two fractions (Rf 0.83 and 0.66) that were stained with iodine. The data suggest that the substances co-isolated with sIgA are phospholipids. At 25 nM ATP, casein and lipids are 32P-labeled. At 1 microM ATP, the sIgA polypeptides are also phosphorylated. Gentle removal of the lipids from Ab preparation enhanced 32P incorporation into casein and sIgA polypeptides. Considering the heterogeneity of polyclonal sIgA in protein and ATP affinity, it is suggested that phosphorylation of casein and sIgA polypeptides is catalyzed by abzymes of different clonal origin.

Chromatography, Liquid↗
PubMed1998

Human breast milk immunoglobulins G hydrolyze nucleotides.

Catalytically active antibodies, abzymes, appear in the blood of mammals immunized with the analogs of transition state or in the case of autoimmune diseases. Until recently, it was not shown whether abzymes exist in the blood of apparently healthy subjects. We have discovered that secretory IgA (sIgA) from the milk of healthy mothers catalyze phosphorylation of a variety of proteins and that IgG can hydrolyze DNA and RNA. In this study for the first time it is shown that IgG from human milk (and their Fab-fragments) also catalyze hydrolysis of nucleoside mono-, di-, and triphosphates. The data meet certain stringent criteria, unambiguously indicating that the observed catalytic activity is associated with IgG rather than contaminating enzymes. Although the nucleotide-binding site of IgG is located in the light antibody chain, L-chains per se cannot hydrolyze NTP unlike the DNA-hydrolyzing abzymes. Kinetic and thermodynamic parameters that characterize the interaction of NTP and dNTP with IgG-abzymes were analyzed. Possible reasons for appearance of polyclonal abzymes with different catalytic activities in the milk of healthy mothers are considered.

Adenosine Triphosphate↗
PubMed1998

Interaction of human milk lactoferrin with ATP.

Human lactoferrin exhibits many unique properties. It is known as one of the most important factors that provide nonspecific defense of cells against bacteria, viruses, and carcinogenesis, as well as an important component of a specific system responsible for the passive immunity of newborns. As a compound with extremely broad spectrum of functions many of which were not elucidated so far, lactoferrin is intensely studied. In this study we obtained electrophoretically and immunologically homogenous preparations of lactoferrin from human milk. Using various methods, we were the first to show that the fraction of lactoferrin, which displays an increased affinity for Sepharose Blue, forms complexes with ATP with a stoichiometry of 1 mole ATP per mole protein. It is shown that the ATP-binding site is located in the C-terminal domain of the lactoferrin molecule. The binding of ATP results in the dissociation of tetrameric forms of the protein and a change in the mode of interaction of lactoferrin with polysaccharides and other proteins. The data may be used in analysis of the possible reasons for multifunctional properties of lactoferrin and possible ways of regulation of its functions.

Adenosine Triphosphate↗
PubMed1997

DNA-hydrolyzing activity of the light chain of IgG antibodies from milk of healthy human mothers.

Various catalytically active antibodies or abzymes have been detected recently in the sera of patients with several autoimmune pathologies, where their presence is most probably associated with autoimmunization. Normal humans are generally considered to have no abzymes, since no obvious immunizing factors are present. Recently we have shown that IgG (its Fab and F(ab)2 fragments) from the milk of normal humans possesses DNase activity. Here we demonstrate for the first time that the light chain of IgG catalyzes the reaction of DNA hydrolysis. These findings speak in favor of the generation of abzymes in the tissue of healthy mothers, and since a mother's breast milk protects her infant from infections until the immune system is developed, they raise the possibility that these abzymes may contribute to this protective role.

Antibodies, Catalytic↗
PubMed1996

Phosphorylation of different human milk proteins by human catalytic secretory immunoglobulin A.

The ability of secretory immunoglobulin A (slgA) from milk of healthy mothers to phosphorylate various milk proteins in the presence of gamma-[32P]-ATP was shown to be a property of the antibodies. The polyclonal slgA was purified by sequential chromatography on Protein-A Sepharose and DEAE-cellulose, and then separated by chromatography on the ATP-Sepharose. The preparations containing all milk proteins except for protein kinases [integrated milk proteins (IMP)] were obtained by extraction of the kinase activities from the milk using their affinity to the insoluble crosslinked staphylococcus. Addition of slgA fractions (having a different affinity to ATP) to the IMP led to phosphorylation of casein and several other milk proteins with different efficiencies.

Adenosine Triphosphate↗