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Biomedical subjects

B A Fedorov

Publications and source records attributed to B A Fedorov.

At least 19 recordsLinked to original sources
PubMed1992

[Changes in nucleotide DNA structure and adhesive properties of blood leukocytes in early period after irradiation of animals].

Postirradiation changes of adhesive properties and supercoiled nucleoid DNA structure of blood leukocytes were studied in Macaca nemestrina and in rats. The dynamics of membrane changes demonstrated a temporary increase of the leukocyte adherence 24 h after nonlethal irradiation of rats, followed by a decrease of this parameter to normal levels on h 48. After lethal irradiation of both animal species the increase in adhesive leukocytes fraction was shown already on hr 3. This higher index was observed until the end of experiments (5 days). Early (on h 3-6) temporary loosing of supercoiled DNA structure was demonstrated in the total blood leukocytes of nonlethally irradiated animals, this seems to be connected with lymphocyte changes. This process was not dependent on altered adhesive properties of leukocyte membranes. The membrane changes of leukocytes preceded decondensation of supercoiled DNA after lethal irradiation of animals. Loosing of supercoiled DNA progressively increased on hour 24 and in later postirradiation period.

Adhesiveness↗
PubMed1991

[10 years' experience of heart valve bioprostheses. Present status and future development].

Long-term results of mitral valve replacement with bioprostheses of three original designs are overviewed. Refinement of the supporting framework design, and of modelling and conservation methodologies has made it possible to improve the survival rates and provided for the absence of specific complications in two groups of patients. Experimental evidence allows for anticipating an increase in the terms of bioprostheses performance.

Adolescent↗
PubMed1987

[Diagnosis of dysfunctions of heart valve bioprostheses].

Twenty-three cases of bioprosthetic dysfunction due to infectious endocarditis and primary tissue degeneration are reviewed. Twelve bioprostheses were studied morphologically. Follow-up of bioprosthesis-wearers for timely diagnosis of bioprosthetic dysfunction can be based on routine clinical investigation procedures. Echocardiographic detection of calcified vegetations on the cusps, as well as thrombosis, incompetence and marked stenosis of the bioprosthesis are indications for repeated surgery.

Adolescent↗
PubMed1985

[Dynamics of the phonocardiographic picture following the bioprosthesis of the mitral valve].

Patterns of phonocardiographic changes were studied in 67 patients (aged 20 to 51 years) with acquired mitral disease 2 months to 6 years after the implantation of aortic xenobioprostheses, preserved in glutaraldehyde and mounted on a hard or flexible support. Phonocardiographic findings were compared with intracardiac hemodynamic data. Three stages and three types of phonocardiographic pattern were identified in patients with normally functioning xenobiovalves. As the postoperative period grew longer, the patients showed progressively smaller amplitudes of tones I and II, a smaller, if any, systolic output murmur and diastolic murmur; some patients no longer exhibited the prosthetic opening tone. PCG parameters showed stability between 2 and 6 years of follow-up.

Adult↗
PubMed1977

[Diffuse x-ray wide-angle scattering of polyglutamic acid in solution].

The diffuse wide angle x-ray scattering (WAXS) of polyglutamic acid (PGA) in solution was studied using an x-ray diffractometer with small aperture of the primary beam. The scattering curve was recorded at an angular interval from (article: see text). The experimental scattering intensity of PGA with alpha-helical CD spectrum showed a maximum at 14.4 nm-1. Unordered PGA in solution yielded no maximum at this scattering angle. The studies have proved that the scattering theory can be applied to globular proteins in solution as well as to chain molecules in solution in this angular interval. The differences between the calculated scattering curves and the experimental curves indicate minor movements of the side chains of PGA in solutions and slight structuring of the solvent at the surface of the polypeptide chain.

Glutamates↗
PubMed1975

Diffuse scattering of x rays by polypeptides and proteins in solution. III. Analysis of scattering curve of sperm whale myoglobin.

X-ray scattering curves for the sperm whale myoglobin molecule and a model which includes only the helical regions of the polypeptide chain are calculated. The portion of the scattering curve associated with the packing of the helices inside the protein globule is analyzed. The model of the myoglobin molecule is used to investigate the sensitivity of the scattering curve to changes in the mutual packing of the helical regions.

Animals↗