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Biomedical subjects

A V Kozlov

Publications and source records attributed to A V Kozlov.

At least 19 recordsLinked to original sources
PubMed1995

Ex vivo demonstration of nitric oxide in the rat brain: effects of intrastriatal endothelin-1 injection.

Nitric oxide (NO) is a novel transmitter with multiple functions in endothelium and neuronal tissue. In particular, it has been implicated in the pathogenesis of neurodegenerative diseases. The aim of the present study was to demonstrate the ex vivo detection of NO in basal conditions and after ET-1 intrastriatal injection by means of electron paramagnetic resonance (EPR) spectroscopy using locally injected hemoglobin (Hb) as a NO trapping agent. The extent of neostriatal damage after Hb and ET-1 injections was assessed by means of immunocytochemistry with a monoclonal antibody against dopamine and cAMP-phosphoprotein M(r) 32 (DARPP-32), which is considered a marker of striatal intrinsic neurons. In the absence of local Hb injection, no signal related to endogenous NO was detected in the neostriatum, suggesting that endogenous NO trapping agents are not sufficiently concentrated to allow NO detection with the present technique. Instead, 1 h after Hb injection, a clear nitrosyl-Hb signal can be detected in neostriatal homogenates. ET-1, a powerful vasoconstrictor agent, was used to cause neuronal loss in the neostriatum. No change in nitrosyl-Hb signal was observed in neostriatal 1 h after ET-1 injection, whereas an almost 3-fold increase in the signal intensity was present 24 h after ET-1 injection. The analysis of neostriatal damage showed that Hb injection did not cause either significant damage of striatal tissue or potentiation of ET-1-induced lesions. In conclusion, the present technique allows ex vivo detection of NO in the brain. The delayed increase in NO observed after ET-1 injection indicates that this molecule may participate in the development of slowly progressive neuronal damage occurring at late post-ischemic times.

Animals↗
PubMed1995

[Analysis of a chromosomal DNA fragment isolated from a hybrid autonomous plasmid of Chlamydomonas reinhardtii].

The ability of a previously cloned fragment of nuclear DNA of Chlamydomonas reinhardtii (a 2.4-kb BamH 1-EcoR I fragment) to function as the origin of replication of plasmid pARG7.8.2.4, carrying the homologous arg7 marker gene of prototrophy or arginine in cells of C. reinhardtii transformants, was studied. As shown by Southern blotting, plasmid pARG7.8.2.4 integrates at several sites of chromosomal DNA of chlamydomonas without autonomous maintenance in cells. Results obtained using Southern blotting and plasmid rescue techniques demonstrated that plasmid pARG7.8, containing only the arg7 gene, is able both to integrate into the chromosome and to be maintained, in some cases, in the autonomous state in Arg+ transformants of alga. Analysis of the nucleotide sequence of the DNA fragment under study revealed several types of GC-enriched repeats that manifested homology with the nucleotide sequence of the arg7 gene in introns 10 and 12.

Animals↗
PubMed1992

Immunoelectronmicroscopic study of the nucleoid structure of hydrogen bacteria.

Electron microscopical studies of the nucleoid structure of hydrogen bacteria using ultrahin sections and spread DNA from bacterial cell lysates revealed a different DNA packaging in the cell. A compact state of the major part of DNA at all growth stages and stability of nucleosome-like structures were shown. The use of antibodies to HU protein of E. coli labelled by protein A-colloidal gold demonstrated the immunological relationship between HU protein of E. coli and histone-like proteins of Alcaligenes eutrophus and their possible role in the nucleosome-like DNA packaging in procariotic genome.

Alcaligenes↗
PubMed1992

Intracellular free iron in liver tissue and liver homogenate: studies with electron paramagnetic resonance on the formation of paramagnetic complexes with desferal and nitric oxide.

Treatment of intact liver and liver homogenate with sodium nitrite, or desferal, brings about the appearance of g = 2.03 and g = 4.3 electron paramagnetic resonance spectroscopy (EPR) signals, respectively. The g = 2.03 signal is conditioned by the formation of dinitrosyl complexes of Fe(II); the g = 4.3 signal is related to the appearance of paramagnetic desferal-Fe(III) complexes. Desferal and sodium nitrite were administered successively into liver homogenate, resulting in only a g = 4.3 EPR signal. And, vice versa, if desferal was administered after sodium nitrite, there appeared only the signal with g = 2.03. These data testify to the fact that one and the same endogenous free iron is included in both paramagnetic centers. The concentration of iron ions was measured in intact tissue according to the formation of dinitrosyl-iron complexes and desferal-iron complexes. It was 33.2 +/- 4.6 and 20.3 +/- 4.0 nmol/g of tissue weight, respectively. The data obtained testify to the fact that free endogenous iron is present in intact tissue. Possibilities of the EPR method for estimation of the content of intracellular free iron are discussed.

Animals↗
PubMed1992

[Increased lipid peroxidation in the rat hypothalamus after short-term emotional stress].

Concentrations of TBA-reactive substances (TBARS) were measured spectrophotometrically in homogenates of small samples of the brain (hypothalamus, parieto-occipital, sensori-motor and limbic cortex), heart, liver and adrenals of male August and Wistar rats; the former strain is more susceptible to emotional stress than the latter one. Forced isolation of the rats in the restraining plastic cages for 1 h increased the TBARS concentrations in the hypothalamus and liver in August rats only. TBARS accumulation in some tissues correlated with such indices of emotional stress as the changes in relative weight of thymus and adrenals. As regards the brain regions, after 1-hour emotional stress the TBARS levels were no longer different because of an increment in hypothalamic TBARS concentration. However, in control conditions the hypothalamus had significantly lower TBARS levels than any other brain structure both in Wistar and August rats.

Animals↗
PubMed1991

Extracorporeal mechanical pulsatile pump and its significance for myocardial function recovery and circulatory support.

The authors performed 12 acute (on dogs) and 12 chronic (on calves) assisted circulation experiments with the use of the total extracorporeal mechanical pump (TEMP) artificial ventricles. The functional morphological research of the myocardium suggests that in addition to the possibility of the biological heart function full replacement, the artificial ventricle also helps recover damages in both the myocardial infarction and distal zones. The critical time period up to the onset of artificial circulation is not more than 2 h, and after that myocardial changes are irreversible.

Animals↗
PubMed1991

Antioxidant properties of albumin during the oxidation of linolenic acid and low density lipoproteins in the presence of ferrous ions.

A spin-labelled fatty acid with an epr spectrum that is sensitive to the localization of the probe was used to show that albumin binds free fatty acids present in solution and also free fatty acids present in low density lipoproteins (LDL). Furthermore, albumin binds the thiobarbituric acid-reactive (TBA-reactive) products formed during the oxidation of linolenic acid, whereas the TBA-reactive substances formed during the oxidation of LDL are not bound by albumin. Linolenic acid bound to albumin essentially does not undergo peroxidation in the presence of ferrous ions, in contrast to a suspension of linolenic acid and LDL in which peroxidation occurs quite readily in the presence of ferrous ions. The highest rate of oxidation was found for linolenic acid alone. Albumin-bound spin-labelled fatty acid was essentially not reduced by ferrous ions, whereas free fatty acid or fatty acid incorporated into LDL was reduced quite rapidly, the highest rate of reduction being for free fatty acids. Thus the ability of fatty acids to undergo oxidation correlates with their accessibility to ferrous ions. The data obtained indicate that serum albumin is a relatively effective antioxidant in the blood and its mode of action is based on the immobilization of free fatty acids.

Animals↗
PubMed1991

Comparative immunochemical analysis of the antigenic structures of the DNA-binding histone-like HU protein from Escherichia coli and eukaryotic histones.

The general antigenic structures of the DNA-binding HU protein from E. coli, histones H1, H2A, H2B, H3, and H4 from calf thymus, and histone H5 from chick erythrocytes were compared in immunoassays with the aid of monospecific polyclonal antibodies to the HU protein and the individual histones. A partial cross-reaction between the HU protein and antibodies to histones H1 and H5 was demonstrated. The reaction titres obtained in a solid-phase enzyme immunoassay indicated that the cross-reactions were equivalent to 30% of the reaction with homologous antigen for antibodies to H1, and to 20% and 12% (on dilution of HU protein in solutions of low and high ionic strength, respectively) of the reaction with homologous antigen for antibodies to H5. Cross-reactions between antibodies to the HU protein and histones H1, H5, H2A, H2B, H3, and H4 were not detected. We suggest that the resemblance between the general antigenic structures of the DNA-binding HU protein from E. coli and the lysine-rich linker histones H1 and H5 reflects the structure of the binding sites between these proteins and DNA, which presumably have a similar DNA-binding pattern and a similar functional role.

Animals↗
PubMed1991

[Carcinoids].

The clinical features, diagnosis, treatment and long-term results in 24 patients with carcinoids of the different organs were studied. Benign carcinoid was revealed in 2, that with a potential malignancy--in 2, a malignant one--in 20 patients. In 6 patients, the combination of carcinoid and cancer of different location was observed. A radical operation was performed in 17 patients. Nine patients died, of them 3--from spreading of cancer of different location.

Adolescent↗
PubMed1990

[Caused of intensified lipid peroxidation in the blood of patients with viral hepatitis B].

The tissue oxygen concentration, the serum antioxidant system state and the serum malondialdehyde (MDA) concentration were studied in patients with hepatitis B. The good correlations were studied in patients with hepatitis B. The good correlations between MDA concentration in patients serum and the oxygen concentration in tissues (R-0.79), and the cytoplasmic enzymes activity (R-0.75 for lactate dehydrogenase; R-0.75 for alanine transferase) were found. On the other hand, it was shown an antioxidant activity decrease of ceruloplasmin-transferrin system in patients serum. It is proposed, that the tissue hypoxia and the decrease of the serum antioxidant activity are the general factors leading to the MDA accumulation in the serum of patients with hepatitis B.

Adolescent↗
PubMed1989

[Indices of lipid peroxidation and the ceruloplasmin-transferrin antioxidant system in donors].

The blood serum ceruloplasmin, transferrin, malonic dialdehyde, iron and copper levels have been measured in donors. These parameters varied in groups of subjects aged 20-29 and 30-45, no age-associated differences being recorded within both the groups. Certain differences have been revealed between the donors who furnished their blood more or less than 3 times a year. The results of this investigation may be useful in clinical screenings of donors.

Adult↗
PubMed1989

[Electrophoretic study of protein secretion by the prostate gland in chronic prostatitis and pathospermia].

Disk electrophoresis of prostatic secretion proteins in polyacrylamide gel has been employed in examinations of 294 normal subjects and sterile patients with oligo- and asthenospermia in the presence of and without chronic prostatitis. The electrophoregrams have been examined visually; the electrophoretic mobility (EPM) of individual fractions relative to the length of the indicator run has been determined. Analysis of the electrophoretic picture, the microscopy findings of examinations of prostatic secretion and the ejaculate, and of the blood levels of sex and gonadotrophic hormones in the patients has revealed that the progress of the inflammatory process in the prostate is associated with a drastic decrease of the concentrations of prostatic secretion proteins with a high molecular mass and an increased level of low-molecular proteins. Abnormal spermatogenesis without prostatic inflammation is linked with a different pattern of prostatic protein levels. A specific electrophoretic picture is characteristic of congestive prostatitis, this helping to differentiate this condition from prostatic inflammations. High informative value and good reproducibility of disk electrophoresis of the prostatic secretion proteins recommend this method for wide use in practical andrology.

Adult↗
PubMed1989

[The measurement of the amount of iron (III) complexes with desferal in the perfused rat liver by an EPR method].

Rat liver was perfused by Hank's solution, containing desferal (deferoxamine). It was shown that in perfusion of the liver spectrum EPR a signal (g = 4.3; H = 63 G) appears. This signal belongs to desferal complexes, containing intracellular Fe/3/. Desferal transfer to the liver tissue and further formation of desferal complexes there takes place within first 5-10 min of liver perfusion by solution, containing 0.5 mM of desferal.

Animals↗
PubMed1989

[Level of Hu protein binding with DNA and the Hu/DNA ratio in Escherichia coli cells with various generation periods].

The possibility of quantitative determination of protein HU in E. coli cell lysates was demonstrated, using enzyme immunoassay with monospecific polyclonal antibodies against HU and homogeneous protein HU. The protein HU/DNA ratio in two cultures of E. coli with different generation periods was found to be constant despite the differences in the levels of proteins HU and DNA. Protein HU was found to be represented by approximately 420.10(3) copies per fast growing. E. coli cell and by 320.10(3) copies per slowly growing cell. These amounts of the HU protein correspond to a ratio of one protein HU molecule per 44 +/- 8 base pairs of DNA and can provide for the nucleosome-like organization of approximately 30% of E. coli DNA length. The constant HU/DNA ratio which is similar to constant histones/DNA ratio provides additional evidence in favour of functional similarity of the HU E. coli DNA-binding protein to histones.

Bacterial Proteins↗
PubMed1989

[Antioxidant therapy in the complex treatment of late pregnancy toxemia].

Lipid oxidation blood levels, activity of serum antioxidative system and erythrocytic membranes were investigated in the time-course of treatment of 145 pregnant females with nephropathies of various severity. More pronounced improvement of the parameters studied and elimination of late gestosis symptoms were revealed in the treatment with antioxidative preparations, lipostabil and solcoseryl. Regardless of treatment pattern in pregnancies complicated by severe nephropathy there were improvements noted, as a rule, in presence of pharmacological management but after its withdrawal the signs of the diseases relapsed (2-6 days after). Continuation of pregnancy up to the terms when the fetus was expected to be born viable was considered as the main target of the aforementioned treatment.

Actihaemyl↗