PubMed Health⌕ Search

Biomedical subjects

I I Nikol'skaia

Publications and source records attributed to I I Nikol'skaia.

At least 19 recordsLinked to original sources
PubMed2003

[Diagnostic implications of detecting antibodies to angiotensin-converting enzyme and its substrates].

The results of the analysis of diagnostic significance of examination of natural antibodies (Nab) to agiotensin-converting enzyme (ACE) and its substrates in the serum of hypertensive patients indicate that concentration of Nab to ACE differ from this mean concentration in donors. An elevated level of Nab to ACE may be considered as a compensatory reaction to increased content of the enzyme in vascular endothelium and blood flow. The same patients were examined for antibodies to peptide angiotensin II (AT-II). Enzyme immunoassay has shown that a significantly elevated level of antibodies to AT-II was only in 5 examinees. The same patients had also high Nab to ACE. The study of a group of ischemic heart disease patients with adverse effects attributed to bronchial affection treated with enalapril and diroton (ACE inhibitors) demonstrates that deterioration of cough and external respiration function is not related to exacerbation of existing chronic pulmonary inflammation. None of the patients had elevated body temperature or inflammatory changes in the blood, other signs of inflammation. Enzyme immunoassay also proved that the initial level of Nab equaled mean value for donors or was insignificantly lower. Blood serum patients with side effects contained a significantly (p < 0.02) elevated quantities of Nab to bradikinin vs initial values. Thus, the proposed method of solid phase enzyme immunoassay quantifies Nab to ACE and its substrates in the patients.

Angiotensin II↗
PubMed2003

[The role of the components of the renin-angiotensin system in the ocular tissues in norm and pathology].

Different components of the renin-angiotensin system (RAS), whose content and activity are predetermined by local factors, are generated in the ocular tissue structures. The local eye RAS plays an important role in pathogenesis of different eye diseases and in the local manifestations of general pathological processes. Therefore, a study of the eye RAS components in norm and in disease contributes to understanding the pathogenesis of eye diseases and opens up new possibilities for an adequate treatment. The RAS components in the lacrimal fluid can be an important characteristics of such diseases like keratitis, diabetic retinopathy etc.

Bradykinin↗
PubMed2001

[Autoantibodies to vasoactive peptides and angiotensin converting enzyme in patients with systemic diseases of the connective tissue].

AIM: To estimate the level of natural autoantibodies (NAAb) to angiotensin-converting enzyme (ACE) and endogenic mediators affecting vascular tone (bradykinin--BK, angiotensin II--AII, vasopressin--VP) as well as the activity of serum ACE in patients with systemic diseases of the connective tissue. MATERIAL AND METHODS: Levels of NAAb were measured by enzyme immunoassay in sera from 30 patients with SLE, 19 patients with rheumatoid arthritis (RA) and 36 patients with scleroderma systematica (SS). Serum from donors served control. IgM NAAb to ACE were measured by a new technique. Serum ACE activity was determined by the initial velocity of hydrolysis reaction using spectrofluometry. RESULTS: IgM NAAb were detected in the sera of both patients and donors. SS patients had the level of NAAb to ACE in diffuse form significantly higher than in limited (p < 0.05). In SLE and SS patients ACE activity was significantly lower (p < 0.05) than in healthy subjects and RA patients. Levels of NAAb to BK was significantly elevated (p < 0.01) in patients with SLE and RA vs donors while to AII in SS patients it was lowered (p < 0.001). Patients with diffuse SS had NAAb to BK higher than patients with SS limited form (p < 0.01). In SLE the lowest levels of NAAb to all the mediators studied were observed in patients with nephritis, for NAAb to VP the differences were significant (p < 0.05). In patients with urinary syndrome concentration of NAAb to BK was significantly higher (p < 0.01), differences between their levels in patients with nephritis and urinary syndrome were also significant (p < 0.05). CONCLUSION: Further studies are needed for specification of physiological or pathological role of NAAb to endogenic mediators.

Angiotensin II↗
PubMed2000

[Detection of natural anti-angiotensin converting enzyme antibodies in human serum using immunoenzyme technique ].

Solid-phase enzyme immunoassay (EIA) was developed for detecting natural antibodies to angiotensine-converting enzyme (ACE). Optimal conditions for detecting natural anti-ACE by EIA in the sera of donors and patients with disorders of arterial pressure are selected. The findings indicate that the level of natural anti-ACE is normally constant, while in the patients it is increased in 50% cases.

Adult↗
PubMed1995

[Angiotensin-converting enzyme in an OAT-octane reversed micelle system: interaction with the matrix].

Regulation of catalytic activity and intramolecular structure of the bovine lung angiotensin-converting enzyme was studied using reversed micelles in a sodium docusate-water-octane system, which model the enzyme's environment in vivo. The catalytic parameters of monomeric and dimeric forms of the enzyme in the reversed micellar system were evaluated. The catalytic activity of the angiotensin-converting enzyme extracted from bovine lung with Triton X-100 did not depend on the detergent concentration at a constant level of hydration. An artificially hydrophobized form of the angiotensin-converting enzyme was obtained by modifying the enzyme with stearic acid chloride. The modification leads to the dependence of the catalytic activity on the surfactant concentration, which provides evidence that the enzyme interacts with the micellar matrix. The modified enzyme showed a significant increase in catalytic activity in the reversed micellar system.

Amino Acid Sequence↗
PubMed1994

[Regulation of catalytic activity and supramolecular structure of angiotensin-converting enzyme in reversed micelles of aerosol OT in octane].

Regulation of the catalytic activity and the supramolecular structure of the angiotensin-converting enzyme isolated from bovine lungs has been studied in a system of reversed micelles of aerosol OT (AOT) in octane. The curve for the dependence of the enzyme catalytic activity on the degree of the surfactant hydration (micellar size) has two maxima at the hydration degrees of [H2O]/[AOT] 27 and 31. Data from velocity sedimentation suggest that depending on the hydration degree, the angiotensin-converting enzyme occurs in the system of reversed micelles in both monomeric and dimeric forms, the latter being catalytically active. In contrast with aqueous media, in the reversed micelle system the angiotensin-converting enzyme does not require chloride anions for its catalytic activity. In the system of reversed micelles of AOT in octane the holoenzyme is stable, while the apoenzyme rapidly and irreversibly loses its activity. Under these conditions the apoenzyme shows an ability to incorporate the Zn2+ ions into the enzyme active center; however, only in the presence of a substrate or an inhibitor.

Adenosine Diphosphate↗
PubMed1993

[Human thyroid gland DNA methylase in nodular and diffuse goiter].

The heterogeneity and some properties of DNA-methylases isolated from nonmalignant human thyroid formations--nodular and diffuse goiters--have been studied. Isoelectrofocusing of methylase preparations produced 6-7 distinct activity peaks distinguished by pI, activity towards Ca2+ and Mg2+, sensitivity towards dithiothreitol and capacity to methylase cytosine into mono-, di- and tripyrimidine blocks in vitro. The degree of DNA methylation in vivo depended on the origin of of the goiter. Analysis of several methylase fractions by two-dimensional electrophoresis performed according to O'Farrell revealed the presence of major polypeptides having similar molecular masses (approximately 36 kDa). Besides the major component, all the preparations under study contained 6-10 characteristic minor components. The data obtained are suggestive of a structural and functional heterogeneity of human methylases.

DNA Modification Methylases↗
PubMed1993

[A new method of isolation and purification of SsoII restriction endonuclease].

A new method for isolation and purification of restriction endonuclease SsoII which results in a homogeneous preparation suitable for all types of fine physico-chemical assays has been elaborated. The procedure includes four chromatographic steps: fractionation on butyl-Toyopearl, combined chromatography on SP-Toyopearl and phosphocellulose PII, and chromatography on DEAE-Toyopearl and on QAE-Toyopearl. The use of fast flow sorbents (Toyopearl) makes it possible to reduce the time needed for the separation of proteins and to optimize the fractionation conditions, thus avoiding the dialysis between the chromatographic steps which significantly decreased the enzyme activity yields in previous purification schemes. The isolation of restriction endonuclease SsoII by the new method usually takes four days.

Chromatography, Ion Exchange↗
PubMed1992

[Change in the cleavage site of synthetic substrates of SsoII restriction endonucleases upon introduction of non-nucleotide inserts in the recognition segment].

The cleavage of synthetic DNA duplexes containing 1,3-propanediol, 1,2-dideoxy-D-ribofuranose or 9-[1'-hydroxy-2'-(hydroxymethyl)ethoxy]methylguanine (glG) residues instead of one of dG residues or one of the nucleosides of the central base pair of the recognition site by SsoII restriction endonuclease (decreases CCNGG) has been studied. It is found that the non-nucleotide insertions (except for glG) result in a change of the SsoII cleavage site and an increase of the efficiency of the cleavage. The novel noncanonical cleavage occurs at the phosphodiester bond adjoining the non-nucleotide insert from the 5'-end.

Autoradiography↗
PubMed1991

[Isoelectric focusing of methylation and restriction enzymes from Staphylococcus aureus strain 6782].

The behaviour of methylation and restriction enzymes of Staphylococcus aureus 6782 during their isoelectrofocusing on ampholinese was studied. It was found that the RSau 6782 isoenzyme is represented by two isoforms, RI and RII, with isoelectric points of 4.2 and 7.9, respectively. Data from isoelectrofocusing analysis suggest that RI and R II are devoid of relaxed specificity found in the original preparation. In was shown that the relaxed specificity is also inherent in the isoschisomeric enzyme, RSau3A. Isoelectrofocusing of the original preparation RSau3A, as in case with RSau 6782, allows the identification of two peaks, RI and RII, and the separation of each peak from the "trace" activity. Multiple forms of DNA-methylase of the Sau 6782 type are represented by four isoenzymes possessing acidic properties. The method allows one to single out from the total methylase pool a modifying methylase with p1 (3.9) is close to that of RSau 6782 and thus the enzyme cannot serve for correct separation of restriction and methylation enzymes of Sau 6782.

Chromatography, Gel↗
PubMed1991

[New systems of host specificity of DNA Pae 610 and Pae 603].

In order to find new systems of host specificity (SHS), wide screening among different strains of Ps. aeruginosa was carried out. By means of cross-titration of phages BT and FP-series two new systems of modification-restriction were identified: Pae 610 and Pae 603. They differ from the known system of host specificity Pae R7.

Anti-Bacterial Agents↗
PubMed1991

[Cleavage of concatamer-type substrates by restriction endonucleases MVA1 and SSO1I].

The interaction of enzymes SsoII (decreases CCNGG) and MvaI (CC decreases A/TGG) with concatemeric DNA duplexes used earlier to study EcoRII (decreases CCA/TGG) TGG was investigated with a view of elucidating the general principles of the restriction endonuclease function. A pattern common for all the three enzymes was observed with DNA duplexes containing AA or TT pairs in the central position of the recognition site. The AA pair blocks or substantially hinders the endonuclease action, whereas the TT pair is either less inhibitory or altogether inert. SsoII, similar to EcoRII was able to processively cleave the concatemeric substrates and to interact with (or to be close to) the hydrogen in the 5th position of the outer dC residue of the recognition site. MvaI was found to differ from EcoRII in the way they recognize and cleave the same nucleotide sequence. The substrate-bound MvaI molecule is incapable of linear diffusion along the DNA. Effective hydrolysis of dU- and m5dC-containing polymers rules out the participation of hydrophobic contacts of the enzyme with the methyl group of the dT residue and with the 5th hydrogen of the outer dC residue of the recognition site in DNA-protein interactions.

Autoradiography↗
PubMed1989

[Use of bacterial DNA-methylases for structuro-functional analysis of the eukaryotic genome].

Bacterial DNA-methylases with known recognition sites (RS) were used as probes for structural-and-functional analysis of eukaryotic genome. Adenine and cytosine DNA-methylases recognizing 4 to 6-member unique and degenerative nucleotide sequences having a symmetrical and asymmetrical structure were used for probing. The use of a set of methylases enabled the selection of a probe that was the most sensitive for the given pathology. Thus, severe hypothyrosis was found to be associated with changes in the acceptor capacity of liver DNA in the heterologous++ methylation reaction as could be evidenced from testing by two probes, CCCC and GAATGC. In the cells of chicken liver hepatoma MC29, the acceptor capacity of DNA during GGA methylation appeared to be altered in the greatest degree. DNA-methylases with degenerative SR are weakly specific probes for the study of structural changes (methylation) of the animal genome.

Animals↗
PubMed1988

[Cytosine DNA-methylase of a SsoII-type from Shigella sonnei 47 cells].

Shigella sonnei 47 cells were found to contain DNA-methylase SsoII which is a modifying component of the system of host specificity of SsoII. The recognition sequence (RS) of methylase SsoII is represented by a five-member palyndromic structure--5'...CCNGG...3'--with a degenerated central nucleotide. Modification of SsoII affords protection of acceptor DNA not only from SsoII type restriction, but also from other restrictases, e. g., Eco RII having an analogous RS but with a less degenerated central nucleotide pair. A simple and rapid procedure for isolation and purification of DNA-methylase ScoII, which employs hydrophobic chromatography on phenyl-Sepharose, has been developed. The enzyme preparation does not contain trace amounts of specific and nonspecific endonucleases and keeps stable on storage in 30% glycerol over a period of one year.

DNA-Cytosine Methylases↗