Biomedical subjects

A M Poverenny

Publications and source records attributed to A M Poverenny.

At least 19 recordsLinked to original sources

PubMed2001

Natural hidden autoantibodies react with negatively charged carbohydrates and xenoantigen Bdi.

Immunoglobulin preparations from sera of healthy donors contain polyspecific autoantibodies interacting with DNA and other charged antigens. These antibodies belong to the IgG class and can exist in the free or hidden state. The hidden antibody activity can be revealed after ion-exchange chromatography on QAE-Sephadex A-50. Immunoenzyme assay was used to assess the interactions of both free and hidden antibodies with different carbohydrates. The hidden antibodies were only able to interact with different polyanionic carbohydrates and neutral xenoantigen Bdi.

Animals↗

PubMed2000

Destabilase from the medicinal leech is a representative of a novel family of lysozymes.

Intrinsic lysozyme-like activity was demonstrated for destabilase from the medicinal leech supported by (1) high specific lysozyme activity of the highly purified destabilase, (2) specific inhibition of the lysozyme-like activity by anti-destabilase antibodies, and (3) appreciable lysozyme-like activity in insect cells infected with recombinant baculoviruses carrying cDNAs encoding different isoforms of destabilase. Several isoforms of destabilase constitute a protein family at least two members of which are characterized by lysozyme activity. The corresponding gene family implies an ancient evolutionary history of the genes although the function(s) of various lysozymes in the leech remains unclear. Differences in primary structures of the destabilase family members and members of known lysozyme families allow one to assign the former to a new family of lysozymes. New proteins homologous to destabilase were recently described for Caenorhabditis elegans and bivalve mollusks suggesting that the new lysozyme family can be widely distributed among invertebrates. It remains to be investigated whether the two enzymatic activities (isopeptidase and lysozyme-like) are attributes of one and the same protein.

Amino Acid Sequence↗

PubMed1999

Reciprocal effect of optical isomerism of EW-dipeptides on immune response.

Dipeptides of the EW-sequence, consisting of D-amino acids, were shown to inhibit spleen colony formation both after in vitro treatment of bone marrow and after the peptide injection to the donor 2-48 h prior to bone marrow taking. The inhibiting effect of D-(EW) peptides can be eliminated by injection of thymic cells to the recipient. L-(EW) peptides have no influence on colony forming activity of intact bone marrow cells but stimulate regeneration of colony formation by irradiated (1 Gy) bone marrow. Unlike L-(EW), the D-(EW) peptides suppress the development of hemopoietic stem cells into the S-phase. Supposedly, D-(EW) represent a new generation of immunoactive peptides possessing of inhibiting activity.

Adjuvants, Immunologic↗

PubMed1999

Histones evoke thymocyte death in vitro; histone-binding immunoglobulins decrease their cytotoxicity.

Effects of various histones, poly-L-lysine, spermine, and the synthetic peptide Arg-Lys-Asn-Val-Tyr-Arg (thymohexine) on intact rat thymocytes were studied. Histones and poly-L-lysine displayed cytotoxicity, causing disorders in the membrane permeability of thymocytes and their death. The dose and time dependences of the effects of histones on thymocytes were determined. Preparations of normal human immunoglobulins bound histones but displayed neither cytotoxicity nor interaction with intact thymocytes. The immunoglobulins significantly decreased the number of dead thymocytes in the presence of total histones. However, the number of cells with detectable immunoglobulin molecules was increased in the presence of histone in the incubation medium. It is suggested that cytotoxicity depends on the number of epitopes on the cell membrane available for interaction with positively charged protein molecules.

Animals↗

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↗

PubMed1997

Effects of low level radiation from the Chernobyl accident in a population with iodine deficiency.

UNLABELLED: To determine the effects of low dose radiation from 131I and 137Cs resulting from the Chernobyl disaster on the expression of endemic goiter in children, we studied children in regions with and without evidence of radiocontamination but comparable iodine insufficiency. We included 89 children in the study (radiocontaminated) region (SR) and 116 in the control region (CR) because they were either fetuses, infants, or pre-adolescents at the time of exposure. We evaluated thyroid dimensions by clinical examination and ultrasound; thyroid function by hormonal levels, and thyroglobulin measurement; histology of the thyroid by fine needle aspiration; and thyroid autoimmunity. SR subjects had 5 times the frequency of thyroid enlargement as those from CR, greatest in the younger patients. There were no instances of clinically apparent thyroid dysfunction. Antithyroid microsomal and antithyroglobulin antibodies were present in a markedly greater percentage of SR subjects. Fine needle biopsy demonstrated greater cellular proliferation in samples from SR. CONCLUSIONS: We have demonstrated findings of autoimmune thyroid disease at markedly increased frequency in a population of children with poor iodine nutriture who were exposed to low level radiation, compared to a more iodine deficient population not so exposed. These results suggest that low level radiation may induce thyroid gland changes in children who have inadequate iodine intake nutriture and reinforce the importance of adequate dietary iodine.

Adolescent↗

PubMed1996

Effect of the peptide of thymic origin (synthetic thymohexine-RKNVYR) on hemopoietic cell progenitors in intact and irradiated animals.

Thymohexine treatment of intact CFU-S was shown not to change their capacity to form colonies both in vivo and in vitro. Thymohexine, similarly to thymus cells, increased colony yield from rabbit antimouse brain antiserum (RAMBS)-treated bone marrow. Combined treatment with thymohexine and thymocytes did not restore colony formation by RAMB serum-treated bone marrow. Thymohexine halved the harmful effect of low doses of ionizing radiation on CFU-S, and, moreover, treatment with the peptide after 4 Gy-irradiation led to more intensive restoration of CFU-S population as compared to control.

Adjuvants, Immunologic↗

PubMed1996

Histones interact with immunoglobulins and give them polyspecificity.

The presence of antihistone antibodies was determined in different commercial immunoglobulin preparations. The ability of histones to perform the function of cofactor in interaction of immunoglobulin preparations and sera of healthy people with charged molecules such as DNA, cardiolipin and phosphatidylcholine, was determined. The addition of histones of immunoglobulin preparations or serum samples is accompanied by forming the stable complex, components of which interact with the charged molecules. The capacity of histones to play the role of cofactor is less evident in the case when they are preincubated with DNA or cardiolipin. The interaction of natural antibodies with histones can explain their polyspecificity in some cases.

Antibodies↗

PubMed1994

Electrochromatography: a method for automatic immunoaffinity chromatography on porous membranes.

Electrochromatography (ECHR) exploits a very high electro-osmotic counterflow developed in porous membranes at discontinuous electrophoresis. This counterflow exceeds considerably the anodic migration of any negatively charged protein and is used as a 'conveyer belt' for sequential transfer of immunoreagents to the specific adsorbents (antigens or antibodies) fixed on the nitrocellulose membrane. This approach was applied for simultaneous detection of two antigens (alpha-fetoprotein and carcino-embryonic antigen) in one sample, for determination of subfractions of alpha-fetoprotein, different in their epitope specificity, and for detection of L chains with certain idiotype on the background of heterogeneous L fraction. ECHR was used also for the partition of different antibodies to DNA adducts, demonstrating the possibility of applying this method to the study of DNA-binding proteins.

Antibodies, Monoclonal↗

PubMed1993

Immunochemical probing of DNA structure with monoclonal antibody to OsO4/2,2'-bipyridine adduct.

Chemical modification with osmium tetroxide (OsO4) in the presence of 2,2'-bipyridine was employed for selective labeling of certain non-B DNA structures. A murine monoclonal antibody (IgG1) specific for deoxythymidine adduct of the modification was produced. It was demonstrated that the level of single-stranded DNA can be evaluated by enzyme-linked immunosorbent assay using the modification and monoclonal antibody. Site-specific OsO4-bipyridine modification followed by dot-blotting was used for probing of some unusual conformations occurring in supercoiled plasmids. The cruciform structures, B-Z junctions, and intramolecular triplex and long (A-T)n inserts were targets for the modification and small quantities of the labeled plasmids can be immunodetected. The method enabled to catch certain structural transitions within the same plasmid in vitro and to detect the left-handed Z DNA labeled inside bacteria. The antibody was also shown to recognize specifically the in situ modified DNA in cell nuclei and polytene chromosomes isolated from Drosophila melanogaster. Preferentially S1-nuclease-sensitive (single-stranded) regions of the nuclear and chromosomal DNA were stained by indirect immunofluorescence after the modification.

2,2'-Dipyridyl↗

PubMed1992

Conversion of DNA adducts of antitumour cis-diamminedichloroplatinum(II). Immunochemical analysis.

Polyclonal antibodies that bind selectively to DNA modified by antitumour cisplatin and its analogues were isolated. The reactivity of the antibodies with the epitope was enhanced by thermal denaturation of DNA that had been modified by cisplatin before its denaturation. On the other hand, denaturation of DNA before its modification resulted in considerably less reaction of the antibodies. The conversion of monofunctional cisplatin-DNA adducts to bifunctional lesions increased the capability of the modified DNA to competitively inhibit the antibodies. The double-helical oligonucleotides containing a unique bifunctional adduct formed by cisplatin at the d(GG) site cross-reacted with the antibodies in contrast to the oligonucleotide containing a single monofunctional adduct formed at the d(G) site. In addition, poly(dG-dC) . poly(dG-dC) modified by cisplatin did not react with the antibodies. It was concluded that the antibodies recognized monodentate lesions, intrastrand cross-links between two purine nucleosides separated by one or more nucleosides and interstrand cross-links negligibly. The antibodies apparently recognized a chemical nature of the bifunctional adduct formed between two adjacent purines and not an unusual conformational feature of DNA resulting from the formation of this adduct. The antibodies were used to analyse the adducts formed by cisplatin on DNA of cultured cells exposed to this drug. During the subsequent incubation of the already exposed cells in the drug-free medium, a part of the bifunctional adducts of cisplatin was completely removed from DNA or transformed to the adducts not recognized by the antibodies.

Animals↗

PubMed1992

Inhibiting effect of charged polymers on interaction of human lupus autoantibodies with certain intracellular proteins.

The influence of charged polymers on the reaction of immunoglobulins from human lupus sera with cellular proteins was investigated in this study. Through immunoblotting it was shown that polyanions (dextran sulfate, heparin, polyinosinic acid) and polylysine inhibited autoantibody binding to several polypeptides of different molecular mass. Using immunofluorescent staining with affinity isolated monospecific autoantibodies it was demonstrated that the immunoreactivity of two nuclear antigens (p30 and p85) and one cytoplasmic antigen (p40) was sensitive to the presence of charged polymers. The inhibiting effect correlated with the concentration of the polymers. The data obtained suggested the competitive mechanism of inhibition of autoantibody-protein reaction by the charged polymers.

Autoantibodies↗

PubMed1992

The atherogenic effect of lupus sera: systemic lupus erythematosus-derived immune complexes stimulate the accumulation of cholesterol in cultured smooth muscle cells from human aorta.

The influence of systemic lupus erythematosus (SLE) patients' sera on lipid accumulation in the cultured smooth muscle cells (SMC) from unaffected human aortic intima was examined. It was demonstrated that the cholesterol uptake in the SMC cultured in the presence of SLE sera is 1.5- to 6-fold higher than in the cells cultured with normal human sera (NHS) obtained from healthy donors. Incubation of the SMC with circulating immune complexes (CIC) isolated from lupus sera by precipitation with 2.5% polyethylene glycol 6000 (PEG) caused a 3- to 4-fold rise in the intracellular cholesterol level. The atherogenic effect of lupus sera, as well as isolated CIC, strongly correlated (r = 0.98) with the low density lipoprotein (LDL) content in the PEG-precipitated CIC. The cholesterol level in cultured SMC also increased 2- to 3-fold when growth medium was supplemented with LDL, DNA, and anti-DNA autoantibodies (IgG) affinity isolated from lupus sera. Using immunofluorescent staining, it was shown that the addition of a DNA-anti-DNA IgG mixture to the growth medium, together with NHS, stimulated LDL incorporation in the SMC. The results of double-label staining suggest the formation of LDL-DNA-IgG complexes which seem to be entrapped in cells more actively than free LDL. The composition of PEG-precipitated CIC was studied by electrophoresis and immunoblotting. Significant amounts of apolipoprotein B, as well as low molecular weight DNA and immunoglobulins, were found in SLE-derived CIC. The data obtained suggest that the atherogenic effect of human lupus sera in vitro is generally due to the appearance of LDL-containing immune complexes. Different mechanisms possibly involved in the lupus atherogenesis are discussed.

Adult↗

PubMed1992

Hidden high-avidity anti-DNA antibodies occur in normal human gammaglobulin preparations.

An ability to detect hidden high-avidity DNA-binding protein in human gammaglobulin samples was investigated. Using ion exchange chromatography on QAE-Sephadex A-50 a highly positive Farr assay DNA-binding fraction was reproducibly isolated from several commercial normal human gammaglobulin preparations. The estimated dissociation constant had a value of 1.04 x 10(-11) M thus confirming high avidity protein-DNA complex formation. Anti-DNA antibodies (Ab) ELISA data revealed that immunoglobulin (Ig) G, IgM and IgA participated in the protein-DNA interaction. Inhibitory experiments involving a number of polynucleotides, synthetic and natural polyanions demonstrated that both double-stranded DNA (dsDNA) and heat-denatured DNA but not RNA inhibited the protein-3H-DNA binding. Generally, the inhibiting effect was more pronounced when purine base-containing polynucleotides and polydeoxy- rather than polyribonucleotides were used. Synthetic polyanions and normal human sera (NHS) also markedly reduced the binding. The presence of hidden high-avidity DNA-binding antibodies in normal gammaglobulin preparations was suggested.

Antibodies, Antinuclear↗

PubMed1992

Trans-diamminedichlorplatinum (II)-modified probes for detection of picogram quantities of DNA.

A novel simple nonradioactive method for detection of specific nucleotide sequences has been developed. This method consists of the hybridization of a target DNA with a DNA probe modified with trans-diamminedichlorplatinum(II) (trans-DDP) followed by detection of DNA/DNA hybrids with affinity-isolated anti-DNA-trans-DDP antibodies and poly-horseradish peroxidase-protein A conjugate. Major advantages of this approach are the low cost and the extreme simplicity of the labeling procedure, which involves only mixing of the reagents. The sensitivity of the proposed technique is sufficient to detect 0.8 pg of DNA in Southern blot hybridization and 25 fg in dot hybridization and permits colony screening.

Antibodies↗

PubMed1991

Probing of DNA structure with osmium tetroxide,2,2'-bipyridine. Adduct-specific antibodies.

Antibodies against DNA modified with a single-strand selective probe, OsO4 in complex with 2,2'-bipyridine (Os,bipy), were raised in rabbits. These antibodies were fractionated using affinity column chromatography and fractions S89-II and S89-III characterized as highly specific for DNA-Os,bipy adduct with no cross reactivity to at least 1000-fold excess of unmodified DNA, RNA and Os,bipy-modified and unmodified proteins. Cross-reactivity to Os,bipy-modified RNA was very small. S89-II showed no cross-reactivity to DNA modified with OsO4 complexed with tetramethylethylenediamine or with bathophenanthroline disulphonic acid and to DNA oxidized with KMnO4. It cross-reacted, however, with DNA modified with OsO4,1,10-phenanthroline complex. The limit of detection of immunodot-blot analysis of extensively Os,bipy-modified DNA was below 0.5 pg. Small extent of Os,bipy-modification of supercoiled and linearized plasmids can be detected by DNA gel retardation and immunoblotting techniques. E. coli cells contain DNA regions in which bases are accessible to the single-strand selective probe.

2,2'-Dipyridyl↗

PubMed1991

Polyclonal antibodies elicited against trans-diamminedichloroplatinum(II)-modified DNA and their application in nonradioactive hybridization experiments.

Polyclonal antibodies that bind selectively to adducts formed with DNA by chemotherapeutically inactive trans-diamminedichloroplatinum (II) [trans-[Pt(NH3)2Cl2]) were produced by immunization with calf-thymus double-helical DNA modified by trans-[Pt(NH3)2Cl2] at a ratio of bound platinum/nucleotide (rb) of 0.1. High selectivity was obtained by separation of the antibodies from the antiserum with the aid of affinity chromatography on a Sepharose column. The antibodies were competitively inhibited in an ELISA assay by 25 pM trans-[Pt(NH3)2Cl2] bound to double-helical DNA and 2.5 pM trans-[Pt(NH3)2Cl2] bound to denatured DNA (rb = 0.1). The conversion of monofunctional adducts, formed on DNA at the early stage of its interaction with trans-[Pt(NH3)2Cl2], to bifunctional lesions, decreased the ability of the modified DNA to competitively inhibit these antibodies. They did not cross-react with unmodified, denatured DNA, but they reacted with diethylenetriamine-chloroplatinum(II)-chloride-modified double-helical DNA and with double-helical DNA treated with cis-diamminedichloroplatinum(II) for a short time (10 min). The results of this work best fit a model in which one of the major antigenic determinants of double-helical DNA modified by trans-[Pt(NH3)2Cl2] is the platinum atom coordinated in a monodentate or bidentate manner with non-paired nucleotide residues or perhaps a short segment of single-stranded DNA which occurs around the platination site. Nucleic acids modified by trans-[Pt(NH3)2Cl2] can be used as immuno-probes in hybridization experiments.

Animals↗

PubMed1991

A monoclonal antibody to DNA modified with osmium tetroxide/2,2'-bipyridine.

A murine monoclonal antibody (IgG) has been generated that binds to DNA modified with osmium tetroxide in the presence of 2,2'-bipyridine and does not interact with unmodified DNA. Reactivity of the antibody was tested by gel retardation assay, ELISA, dot-binding assay and immunoblotting. The results obtained suggest that the antibody does not cross-react with modified or unmodified RNA or proteins. The high specificity of the binding reaction is due to the specific recognition of modified deoxythymidine residue by the monoclonal antibody. A possible way of using the antibody produced is discussed.

2,2'-Dipyridyl↗