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O V Stepanova

Publications and source records attributed to O V Stepanova.

15 recordsLinked to original sources
PubMed2006

Myosin light chain kinase colocalizes with nonmuscle myosin IIB in myofibril precursors and sarcomeric Z-lines of cardiomyocytes.

Myosin light chain kinase (MLCK) is a key regulator of various forms of cell motility involving actin and myosin II. MLCK is widely present in vertebrate tissues including the myocardium. However, the role of MLCK in cardiomyocyte function is not known. Previous attempts to gain insight into possible roles and identify potential molecular partners were disappointing and equivocal due to cross reactivity of early antibodies with striated muscle MLCK, which has a different genetic locus and a divergent amino acid sequence from the above mentioned enzyme. Using an immunofluorescence approach and a panel of antibodies directed against MLCK, cytoskeletal, and sarcomeric proteins, we localized MLCK to myofibril precursors and Z-lines of sarcomeres in embryonic and adult cardiomyocytes. The same structures contained nonmuscle myosin IIB implicating this protein as a possible target of MLCK. Our results suggest a role for MLCK in cardiomyocyte differentiation and contraction through regulation of nonmuscle myosin IIB.

Animals↗
PubMed2004

[A new actin-binding area of the myosin light chains' high-molecular kinase].

High-molecular weight isoform of myosin light chain kinase (MLCK-210) contains a unique N-terminal domain not present in a low-molecular weight isoform, MLCK-108. Functional features of this domain are poorly studied. We provide evidence that N-terminal area of the unique MLCK-210 domain incorporates previously unrecognized actin-binding region that could be involved in the interaction of MLCK-210 with the actin cytoskeleton.

Actins↗
PubMed1995

Multiple gene products are produced from a novel protein kinase transcription region.

The nonmuscle/smooth muscle myosin light chain kinase (MLCK) and the kinase related protein (KRP) that lacks protein kinase activity are myosin II binding proteins encoded in the vertebrate genome by a true gene within a gene relationship. The genomic organization and expression result in the same amino acid sequence in different molecular contexts from two different sizes of mRNA. We report here the identification and characterization of a third size class of gene products. The protein appears to be a higher molecular weight form of MLCK with additional amino terminal tail sequence which might provide differential subcellular targeting characteristics.

Amino Acid Sequence↗
PubMed1995

Stretch affects phenotype and proliferation of vascular smooth muscle cells.

The exertion of periodic dynamic strain on the arterial wall is hypothesized to be relevant to smooth muscle cell morphology and function. This study has investigated the effect of cyclic mechanical stretching on rabbit aortic smooth muscle cell proliferation and expression of contractile phenotype protein markers. Cells were cultured on flexible-bottomed dishes and cyclic stretch was applied (frequency 30 cycles/min, 15% elongation) using a Flexercell Strain unit. Cyclic stretch potentiated smooth muscle cell proliferation in serum-activated cultures but not in cultures maintained in 0.5% fetal calf serum. Stretching induced a serum-independent increase of h-caldesmon expression and this effect was reversible following termination of mechanical stimulation. Strain was without effect on smooth muscle myosin or calponin expression. In cells grown on laminin stretch-induced h-caldesmon expression was more prominent than in cells cultured on collagen types I and IV, poly-L-lysine and gelatin. These data suggest that cyclic mechanical stimulation possesses dual effect on vascular smooth muscle cell phenotype characteristics since it: 1) potentiates proliferation, an attribute of a dedifferentiated phenotype; and 2) increases expression of h-caldesmon considered a marker of a differentiated smooth muscle cell state.

Animals↗
PubMed1991

Expression of calponin in rabbit and human aortic smooth muscle cells.

Polyclonal antibodies to chicken gizzard calponin were used to localize calponin and determine calponin expression in rabbit and human aortic smooth muscle cells in culture. Calponin was localized on the microfilament bundles of cultured smooth muscle cells. Early in primary culture, calponin staining was accumulated preferentially in the central part of the cell body. With time in culture, the number of calponin-negative smooth muscle cells increased while the distribution of calponin in calponin-positive cells became more even along the stress fibers. Calponin content and the calponin/actin ratio decreased about 5-fold in rabbit aortic smooth muscle cells during the first week in primary culture and remained low in proliferating cells. The same tendency in calponin expression was observed when human vascular smooth muscle was studied. On cryostat sections of human umbilical cord, calponin antibodies mainly stained vessel walls of both the arteries and veins, although less intensive labelling was also observed in non-vascular tissue. When primary isolates of human aortic intimal and medial smooth muscle cells were compared with corresponding passaged cultures, it was found that calponin content was reduced about 9-fold in these cells in culture and was similar to the amount of calponin in endothelial cells and fibroblasts. Thus, high calponin expression may be used as an additional marker of vascular smooth muscle cell contractile phenotype.

Animals↗
PubMed1988

Structural and electronic origin of meat odour of organic hetero-atomic compounds.

By means of the electron-topologic approach suggested earlier, the structural and electronic features favouring meat odour occurrence are evaluated using 77 organic compounds with known odorant properties as a basis for primary logico-structural analysis. A general fragment of the type XH2 (where X = S, O, N is a hetero-atom) with a certain electronic structure and conformational property is shown to be responsible for the meat odour. The results obtained allow for a prognosis of odorant compounds and their purposeful synthesis.

Animals↗
PubMed1987

[Specificity of peroxidase-labeled antibodies to rabbit, mouse and human immunoglobulins].

The comparative study of different types of conjugates (antirabbit, antimouse and antihuman) has shown that gamma globulin fractions actively interact not only with homologous peroxidase-labelled antibodies, but also with heterologous ones. Cross reactions were most pronounced between antimouse conjugates and the preparations of human gamma globulin and, vice versa, between antihuman conjugate and mouse gamma globulin. The study has shown that the main cause of cross reactions is the presence of common antigenic determinants in the preparations of mouse and human gamma globulin.

Animals↗
PubMed1986

[Comparative immunochemical characteristics of extracellular polysaccharide-containing preparations and teichoic acids of Staphylococcus aureus].

The sensitivity of the enzyme immunoassay on the basis of polysaccharide-containing preparations was found to be lower than that of the assay on the basis of teichoic acids. The specificity of both assays was 100%. There was no complete coincidence between the results of the detection of antibodies to these two antigens in patients' sera.

Animals↗
PubMedDate not supplied

[Content of myosin-activating protein kinases in myocardium of patients with dilated cardiomyopathy and in the animal heart].

The skeletal myosin light chain kinase (skMLCK) was identified in human and chicken embryo myocardium but not in embryo and adult rat heart using western blotting. The content of skMLCK and myosin-activating protein kinases: RhaA-activated protein kinase (ROCK), integrin-linked protein kinase (ILK), and zipper-interacting protein kinase (ZIPK) was compared in normal human myocardium and the hearts of patients with dilated cardiomyopathy (DCM). It was demonstrated that the content of skMLCK, ROCK and ILK increases in DCM whereas the content of ZIPK decreases. The results obtained may reflect compensatory processes in cardiomyocytes in DMC, which are aimed at increasing their viability and contractility.

Age Factors↗
PubMedDate not supplied

[Central hemodynamics, gas exchange, and gas oxygen-transporting function in combined anesthesia using xenon during operations under extracorporeal circulation].

The advantages of xenon include its good hemodynamic profile and possible cardioprotective properties. The investigation was undertaken to study central hemodynamics, lung gas exchange, and blood oxygen-transporting function in xenon anesthesia in patients operated on under extracorporeal circulation (EC). Fifteen patients aged 41-69 years operated on for coronary heart disease were examined. The severity of the patients' baseline status corresponded to NYHA functional classes I to IV. The duration of an operation was 251 +/- 10 min; that of EC was 97 +/- 5 min; aortic ligation lasted 59 +/- 3 min. After induction of anesthesia with propofol via concentration-regulated infusion (CRI) and with fentanyl, delivery of xenon was initiated at concentrations of 47 +/- 1 to 52.5 +/- 1%, which was mixed with oxygen. Propofol CRI was used during EC. After the latter, xenon was inhaled at concentrations of 47.7 +/- 1 to 53.3 +/- 1%. The mean arterial pressure (BP(mean)), heart rate (HR), and cardiac index (CI) remained unchanged during xenon anesthesia in the preperfusion period. After EC during xenon anesthesia, CI significantly rose with a moderate increase in HR without inotropic support. BP(mean) was moderately, but statistically significantly decreased. Prior to and following EC, there were no changes in the values of blood oxygen-transporting function.

Adult↗
PubMedDate not supplied

[The effect of periodic stretching of the smooth-muscle cells on the expression in them of contractile-phenotype marker proteins].

Cyclic mechanical stretching of the rabbit aortic smooth muscle cells induced a serum-independent increase in the h-caldesmon expression. The expression was more obvious in the cells grown on laminin. The data obtained suggests that the cyclic stretching specifically activates a serum- and matrix-independent expression of h-caldesmon. The mechanical stimulation seems to contribute to the maintenance of the VSMC differentiated phenotype.

Animals↗