Biomedical science (Biomed Sci)

Publications in this journal

• Article: Viral chimeric protein including a determinant of myelin basic protein is capable of inducing allergic encephalomyelitis in guinea pigs.

  S N Shchelkunov, S B Stavitskii, L I Batenko, P V Gashnikov, G A Shchelkunova, O A Kostyrev, L S Sandakhchiev
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  ABSTRACT: A hybrid vaccinia virus expressing a chimeric protein consisting of thymidine kinase and the encephalitogenic determinant, S1, from guinea pig myelin basic protein was constructed. Infection of guinea pigs with the virus resulted in the development of allergic encephalomyelitis.
  Biomedical science 02/1991; 2(5):493-7.
• Article: Continuous distribution of Mycoplasma genome sizes.

  N A Barlev, S N Borchsenius
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  ABSTRACT: Genome sizes of eleven strains of eight species of Mollicutes Mycoplasmataceae were investigated by pulsed-field gel electrophoresis. Mycoplasma genomic sizes were determined from the sum of the sizes of fragments obtained after digestion of genomic DNA with restriction endonucleases. The sizes of the fragments were determined by comparison of their electrophoretic mobilities with those of lambda DNA concatemers. Specific restriction endonucleases were chosen so that after digestion three to ten fragments were obtained. The values for genome size derived by this method showed a continuous distribution that ranged from approximately 650 kb for Mycoplasma hyorhinis BTS-7 to 1600 kb for Acholeplasma laidlawii FHM.
  Biomedical science 02/1991; 2(6):641-5.
• Article: Effect of injection of RNA isolated from normal and epileptic cortexes of rabbits into functioning mollusc neurons.

  A O Dudkin
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  ABSTRACT: Epileptogenic foci were formed in rabbit visual cortex by freezing with liquid nitrogen. RNA isolated from the epileptogenic cortex (RNAepl), or from the frontal lobes (RNAcont) was injected into spontaneously active neurons of the mollusc Planorbarius corneus. The amplitude and duration of the spontaneous action potentials generated following the injection of RNAepl were reproducibly higher than those produced following the introduction of RNAcont. But the time interval between injection and cessation of spontaneous activity was considerably shorter after RNAepl-injection than after RNAcont-injection. Perfusion of neurons with a solution containing puromycin substantially prolonged the period of spontaneous discharge generation in both cases. The addition of Co2+ to the perfusion solution restored the spontaneous rhythmic activity to cells in which the generation of spikes had ceased following the injection of RNAepl. The mechanism underlying these effects is discussed.
  Biomedical science 02/1991; 2(5):489-92.
• Article: Investigation of antigenic structure of attenuated and virulent Venezuelan equine encephalomyelitis virus by means of monoclonal antibodies.

  I A Razumov, E V Agapov, A V Pereboev, E V Protopopova, S D Lebedeva, V B Loktev
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  ABSTRACT: A comparative study of the antigenic structure of virulent strains and attenuated vaccine strains of Venezuelan equine encephalomyelitis virus (VEEV) by means of monoclonal antibodies has made it possible to investigate the antigenic structure of the envelope glycoproteins E1 and E2, and to specify their role in the development of antiviral immunity. On the E1 glycoprotein there are five nonoverlapping antigenic sites consisting of eight epitopes that are recognized by monoclonal antibodies; six sites consisting of twenty epitopes were found on the E2 glycoprotein. The monoclonal antibodies against four sites protect the animals from lethal infection with the virulent strain, Trinidad donkey. Out of the thirteen epitopes identified as being responsible for antiviral immunity, three are changes in the TC-83 strain, and six belong to two sites in the strain 230. The results obtained indicate the necessity for further improvement of the available vaccine preparations against this dangerous infectious disease.
  Biomedical science 02/1991; 2(6):615-22.
• Article: PAF-like activity of O-acetylated sphingomyelin.

  E V Berdyshev, O E Getmanova
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  ABSTRACT: O-acetylated sphingomyelin (Ac-SM) was found to cause aggregation of rabbit platelets in vitro. The Ac-SM-induced aggregation was accompanied by subsequent desensitisation of platelets to platelet-activating factor (PAF). The activity of Ac-SM exceeded that of acyl-PAF by about fourfold. BN 52021, a specific PAF-receptor antagonist, was found to inhibit the Ac-SM-induced aggregation. These results, together with earlier reports that sphingomyelin can inhibit the effects of PAF, suggest a new physiological function for sphingomyelin as a regulator of PAF-receptor binding. A search for enzymes to catalyse specifically the acetylation and deacetylation of sphingomyelin is required to confirm the physiological existence of sphingomyelin derivatives.
  Biomedical science 02/1991; 2(5):485-8.
• Article: Covalent binding of bleomycin to concanavalin A and immunoglobulin G enhances the ability of the bleomycin-Fe(II) complex to destroy the erythrocyte membrane.

  A I Voznesenskii, Galanova YuV, A I Archakov
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  ABSTRACT: The antibiotic bleomycin was examined as a possible component of hybrid molecules composed of an address fragment and a generator of reactive oxygen species. The bleomycin-Fe(II) complex was found to destroy the erythrocyte membrane by generating reactive oxygen. The ability of antioxidants to slow down haemolysis points to a free-radical mechanism for this process. The protective effects of catalase and superoxide dismutase indicate that hydrogen peroxide and the superoxide radical formed on autoxidation of the complex are essential for membrane damage. Haemolytic activity is also exhibited by bleomycin-Fe(III) reduced in the NADPH-cytochrome P450 reductase reaction. The covalent binding of bleomycin to such address molecules as concanavalin A and antierythrocyte immunoglobulin G enhances the ability of the bleomycin-Fe(II) complex to destroy the plasma membrane of erythrocytes.
  Biomedical science 02/1991; 2(2):147-50.
• Article: Diet-induced hypercholesterolaemia in the rabbit.

  A S Ivanov, T I Torkhovskaya, E M Khalilov, A I Archakov
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  ABSTRACT: Intraspecies variation in diet-induced hypercholesterolaemia in rabbits, simulating atherosclerosis, was studied. The chinchilla rabbit population examined contained several subpopulations, as indicated by polymodal forms of histograms of plasma cholesterol levels. This finding indicates that the inclusion of subpopulations in an investigation can lead to erroneous conclusions, and that subpopulations should be identified before such work is undertaken. The relationship between the molar cholesterol/phospholipid ratio in rabbit erythrocyte membranes and the plasma cholesterol level in experimental atherosclerosis was also studied. A correlation was evident only over the range of 1-5 g cholesterol per litre of plasma.
  Biomedical science 02/1991; 2(3):285-8.
• Article: Studies on the N-terminal sequences of lectins isolated from the seeds of Butea frondosa.

  S Padmanabhan, V V Demin, I N Telezhinskaya, E V Zaitseva, T B Golubeva, Chertov OYu
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  ABSTRACT: Two lectin fractions (FI and FII) were obtained from seeds of Butea frondosa by affinity chromatography on a sorbent of macroporous glass coupled to the disaccharide alpha-D-GalNAc-(1----3)-beta-D-Gal. Both of these fractions, although different in their sugar specificity, were found on SDS-PAGE to consist of two polypeptide chains of 33 kDa and 35 kDa. In the native state the subunits associated to form a 250 kDa complex, possibly comprising four molecules of the 33 kDa polypeptide and four molecules of the 35 kDa polypeptide. The presence of a faint 70 kDa band when the 250 kDa complex was subjected to SDS-PAGE may indicate the existence of a sequential mechanism of aggregation. N-terminal amino acid sequence analysis revealed extensive homology between these lectins and those of other Leguminosae.
  Biomedical science 02/1991; 2(6):646-50.
• Article: Neuropeptide Y and catecholamine-mediated neuronal transmission in mechanisms of feeding-behaviour induction.

  E V Borisova, T Kadar, G Telegdi
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  ABSTRACT: Intracerebroventricular administration of various doses of neuropeptide Y (NPY) to rats had different effects on their feeding behaviour: the lowest dose (100 ng) decreased food intake, but higher doses (5 micrograms) markedly increased the intake. Prazosin, a selective blocker of alpha 1-adrenergic receptors, suppressed the effect induced by 5 micrograms (but not 100 ng) NPY. No such effect was observed with injections of yohimbine or propranolol. The opiate receptor antagonist, naloxone, blocked the feeding behaviour induced by 5 micrograms NPY without having any other effects on the responses induced by 100 ng NPY. The data obtained testify to heterogeneity within the NPY receptors of the central nervous system. It is concluded that the effects of high doses of NPY on feeding behaviour are mediated, at least in part, by alpha 1-adrenergic receptors.
  Biomedical science 02/1991; 2(5):455-9.
• Article: Adaptation to short-term stress prevents post-infarction hyperactivation of the endothelium and decrease in blood pressure in rats.

  F Z Meerson, E B Manukhina, A V Lapshin
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  ABSTRACT: The aim of the study was to elucidate the possibility of preventing the decrease in blood pressure (BP) and the endothelial hyperactivation that are induced by experimental myocardial infarction in rats. The endothelial hyperactivation manifested itself in potentiated endothelium-dependent relaxation and in attenuated contractile responses to noradrenaline in isolated rat aortas. Furthermore, the postinfarction changes in BP showed a negative correlation with the endothelium-dependent relaxation. Preliminary adaptation of rats to short-term nondamaging stress exposures or pretreatment with the antioxidant, ionol, prevented to a great extent both the postinfarction decrease in BP and the disturbances in endothelium-mediated responses of smooth muscle. Since, according to the literature, infarction-concomitant stress strongly activates free-radical processes which may result in a hyperproduction of endothelium-derived relaxing factor, it is suggested that the increased potency of anti-oxidant systems is the mechanism common to the protective effects both of adaptation and of ionol.
  Biomedical science 02/1991; 2(6):623-8.
• Article: Disturbances in oxidative phosphorylation in the liver of rats with heliotrine-induced hepatitis and restoration by phosphatidylcholine and ATP.

  Z Z Gizatullina, L M Fesenko, N V Dombrovskaya, E N Mokhova, A N Aripov, A I Gagel'gans, A G Atabekov
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  ABSTRACT: Acute hepatitis induced by heliotrine is accompanied by uncoupling of oxidative phosphorylation in liver mitochondria. The rate of oxygen uptake during succinate oxidation increased in all metabolic states, while the respiratory control index decreased by 45% because of the greater increase in the respiration rate in state 4 by comparison with that in state 3. Heliotrine poisoning also halved the rate of oxygen uptake in rat liver homogenates in the presence of ascorbate and tetramethylene-p-phenylenediamine. This is indicative of a lowering of cytochrome oxidase activity and of energy metabolism disturbances in rat liver. Preparations of cotton phosphatidylcholine (PC), both purified and as ATP-containing complexes (PC+ATP), as well as ATP alone, reduced the metabolic disorders in liver mitochondria of rats with acute heliotrine-induced hepatitis. The therapeutic effect of these preparations consisted in the restoration of oxidative phosphorylation coupling and of the cytochrome oxidase activity. The effect of PC+ATP was much greater than either PC or ATP alone. In contrast, the commercial preparation, Essential, had no beneficial effect.
  Biomedical science 02/1991; 2(5):460-4.
• Article: Synergistic antiproliferative effect of cis-diammine-dichloroplatinum (II) and a new anticancer agent, plasmanyl-(N-acyl)-ethanolamine, an inhibitor of protein kinase C.

  I S Mikhaevich, N K Vlasenkova, G K Gerasimova
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  ABSTRACT: The action of a new anticancer agent, the semisynthetic alkyl-phospholipid plasmanyl-(N-acyl)-ethanolamine (sPNAE), namely 1-O-octadecyl-2-oleoyl-sn-glycero-3-phospho-(N-palmitoyl)-ethanolamine, on protein kinase C (PKC) was investigated, and it was found to inhibit in a dose-dependent manner PKC isolated from mouse brain. The inhibition was competitive with respect to phosphatidylserine (K(i) = 20 microM). Lyso-PNAE, a possible cell metabolite of sPNAE, also inhibited PKC. A two-site model was used to calculate the binding affinity and the number of binding sites for phorbol ester in a culture of human melanoma BRO cells. The values of Kd, the dissociation constant, were K'd = 0.5 nM and K"d = 72 nM, whereas the values of Bmax, the number of binding sites, were B'max = 4.6 x 10(4) sites cell-1, and B"max = 2.9 x 10(5) sites cell-1. sPNAE was able to reduce the affinity of BRO cells for phorbol ester with almost no changes in the number of binding sites: K'd = 1.6 nM, K"d = 557 nM, and B'max = 4 x 10(4), B"max = 1.9 x 10(5). These data suggest that sPNAE may inhibit PKC in intact cells. Since various inhibitors of PKC may enhance the antiproliferative activity of cis-diamminedichloroplatinum(II) (cis-DDP), we investigated the effect of the combination of sPNAE and cis-DDP on the proliferation of BRO cells. sPNAE synergistically enhanced the antiproliferative activity of cis-DDP.
  Biomedical science 02/1991; 2(6):659-64.
• Article: Transformation of rat-embryo immortalized fibroblasts by the E6-E7 region of human papillomavirus type 18.

  E V Komissarova, D D Spitkovsky, F L Kisseljov
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  ABSTRACT: Plasmids containing the E6 and E7 open reading frames of human papillomavirus type 18 transformed rat-embryo fibroblasts when expressed under the cytomegalovirus promoter. The fibroblasts had been previously immortalized with the large T-antigen gene of the polyomavirus to produce rat embryo fibroblast (large T-antigen) [REF(LT)] cells. REF(LT) cells were transformed by the E6 and E7 sequences to anchorage independence and tumourigenicity, but there were no significant morphological alterations. Transformation by these sequences of REF(LT) cells differed from that achieved by pEJras, in which case significant morphological changes and tumourigenicity in nude mice did occur.
  Biomedical science 02/1991; 2(3):305-8.
• Article: Partial purification and characterization of ADP-ribosyltransferase produced by Legionella pneumophila.

  Belyi YuF, I S Tartakovskii, Vertiev YuV, S V Prosorovskii
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  ABSTRACT: A scheme for the partial purification of a Legionella pneumophila product possessing ADP-ribosyl-transferase and NAD-glycohydrolase activities is presented. The purification steps consisted of gel chromatography, ion-exchange, hydrophobic interaction chromatography, and chromatofocusing. The partially purified preparation modified eukaryotic components of molecular mass 20-25 kDa, which it is proposed are GTP-binding proteins. Addition of bivalent cations as well as ATP to the reaction buffer was necessary for ADP-ribosylation. NAD (50 microM) and nicotinamide (16 mM) greatly inhibited incorporation of ADP-ribose into acceptor proteins.
  Biomedical science 02/1991; 2(2):169-74.
• Article: Proper cotranslational insertion of visual rhodopsin into the lipid bilayer occurs in the absence of protein translocation machinery.

  V V Gurevich, I D Pokrovskaya, M N Garnovskaya, I L Dumler, S A Zozulya
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  ABSTRACT: The insertion of visual opsin into membranes occurred during in vitro translation of opsin mRNA in wheat germ extract in the presence of either microsomes or liposomes. The rhodopsin that integrated into both types of membranes after regeneration with 11-cis-retinal was functionally active (in contrast to the nonincorporated protein). Opsin either cotranslationally translocated into microsomes or inserted into liposomes had equal sensitivity to proteolysis and yielded the same pattern of peptides, which differed substantially from the set of peptides produced during proteolysis of opsin not incorporated into membranes. Thus visual opsin does not require protein translocation machinery for proper insertion into the lipid bilayer.
  Biomedical science 02/1991; 2(2):187-92.
• Article: Polymerase chain reaction polymorphisms in HLA-DQ alpha and IL6 from Mongoloid and Caucasoid populations.

  N V Titenko, J H Kurth, A M Bowcock, L L Cavalli-Sforza
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  ABSTRACT: Polymerase chain reaction polymorphisms have been used to study European, Chinese, Russian and Buryat populations at the HLA-DQ alpha and IL6 loci. DNA from individuals in these populations was specifically amplified at these loci, and analyzed either with allele-specific oligonucleotides for HLA-DQ alpha or directly on agarose gels for IL6. Allelic frequencies were calculated for each of the loci in each population. Comparisons between the population frequencies show that the Russian population is more closely related to Europeans, and that the Buryat population is more closely related to Chinese. This finding is in agreement with conclusions based on the phenotypic frequencies of classical blood-group and other protein markers in these populations.
  Biomedical science 02/1991; 2(2):175-9.
• Article: Na(+)-K(+)-ATPase isoforms in different areas of calf brain.

  N M Vladimirova, N A Potapenko, N V Levina, N N Modyanov
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  ABSTRACT: The isoform composition and type of Na(+)-K+ ATPase functional complexes in a number of calf brain membranes were determined. Functionally active enzymes were obtained from microsomes from calf cerebral cortex grey matter, brain stem, and stem axolemma by two different methods involving (1) the selective removal of contaminating proteins according to Jorgensen (1974) and (2) the selective solubilization of the enzyme with subsequent reformation of the membrane structure according to Esmann (1988). The protein components of the isolated preparations were separated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, transferred to an immobilon membrane [poly(vinylidene difluoride) membrane] by electroblotting, and subjected to structural analysis. The N-terminal amino acid sequences of the alpha- and beta-subunits (alpha 1, alpha 2, alpha 3, beta 1, beta 2) and the isoform composition and type of alpha n beta m functional complexes present in the different microsome preparations were determined. Brain grey matter Na(+)-K+ ATPase was characterized by biphasic kinetics with respect to ouabain inhibition (Ki approximately 10(-6) M and -1.5 x 10(-8) M) and comprised a set of isozymes with subunit compositions of alpha 1 beta 1, alpha 2 beta m, and alpha 3 beta m (where m = 1 and/or 2), with the alpha 1 beta 1 form clearly predominating. Na(+)-K+ ATPase from brain stem and axolemma consisted mainly of a mixture of the isozymes alpha 2 beta 1 and alpha 3 beta 1, which had identical ouabain inhibition constants (Ki approximately 10(-7) M), but in the axolemma there was a large quantity of the alpha 3 beta 1 isozyme. The catalytic subunit alpha 3 within the untreated enzyme complex had increased sensitivity towards endogenous proteolysis. It was therefore possible to isolate enzyme containing the alpha 3 catalytic subunit only in the presence of the protease inhibitor diisopropyl fluorophosphate (DIPF). In the absence of this inhibitor there was a specific fragmentation of the polypeptide chain, resulting in the formation of an extremely stable N-terminal fragment of molecular mass 55 kDa.
  Biomedical science 02/1991; 2(1):68-78.
• Article: Amino acid sequence determination of vaccinia virus immunodominant protein p35 and identification of the gene.

  Chertov OYu, I N Telezhinskaya, E V Zaitseva, T B Golubeva, V V Zinov'ev, L G Ovechkina, L B Mazkova, E G Malygin
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  ABSTRACT: A major immunodominant envelope protein of vaccinia virus (protein p35) was purified by extraction from virions with the nonionic detergent Nonidet P-40. The protein was cleaved with cyanogen bromide. Four homogeneous peptides were isolated and their N-terminal amino acid sequences determined. A computer search of a protein-sequence data bank revealed complete identity of the determined sequences with sequences 44-63, 144-149, 154-165, and 224-238 of ORF H3 of the HindIII-H fragment of the vaccinia virus genome (Rosel et al 1986). It has therefore been established that the immunodominant protein p35 of vaccinia virus is encoded by the gene in the HindIII-H fragment of the vaccinia virus genome.
  Biomedical science 02/1991; 2(2):151-4.
• Article: Mechanism of aggregation of fibrinogen molecules: the influence of fibrin-stabilising factor.

  M A Rozenfel'd, M V Vasil'eva
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  ABSTRACT: The physicochemical mechanism of aggregation of fibrinogen has been investigated in the presence and absence of fibrin-stabilising factor (factor XIIIa). Data from elastic and inelastic light-scattering and viscometry show that molecules of fibrinogen undergo a spontaneous modification of their carboxyl terminals and bind 'end to end' into flexible polymer chains. On attaining a critical length, the single-filament polymers twist into a coil and aggregate to form branched molecules in which the segments are packed sufficiently densely to resemble strongly hydrated globular particles. The formation, under the influence of factor XIIIa, of epsilon/gamma-glutamyl-lysine covalent bonds produces only insignificant changes in the spatial organisation of the fibrinogen aggregates. Covalent dimerisation of the gamma-chains restricts the structural flexibility of the polymers, but linking of the alpha-chains provides progressive compaction of the structure with increase in molecular weight. Electrophoresis of reconstituted samples shows that the coil-shaped chains of fibrinogen oligomers prevent the complete enzymatic linking of the gamma-chains. The results of this work suggest that the accelerated assembly of multimolecular aggregates, seen in the presence of factor XIIIa, may be explained by the stabilisation of intermediate complexes of fibrinogen, which makes the spontaneous transition from a stable native state to the activated state irreversible.
  Biomedical science 02/1991; 2(2):155-61.
• Article: Effects of dermorphine on thermoregulation.

  T G Emel'yanova, A B Usenko, A A Kamenskii, V I Deigin, E P Yarova
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  ABSTRACT: Intraperitoneal administration of dermorphine induces dose-dependent changes in the temperature of the body and the tail skin of rats. The character of these changes is largely determined by the ambient temperature, i.e. it depends on the initial functional state of the thermoregulation system. Pretreatment with naloxone reduces the dermorphine-induced effects on thermoregulation but does not eliminate them completely.
  Biomedical science 02/1991; 2(6):601-6.