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Biomedical subjects

D A Voronov

Publications and source records attributed to D A Voronov.

14 recordsLinked to original sources
PubMed2006

[The degree of coronary artery calcinosis as a prognostic factor of asymptomatic cardiovascular complications: results of meta-analysis].

AIM: To investigate prognostic implications of the calcium index estimated tomographycally for identification of patients at high risk to develop cardiovascular complications (non-fatal myocardial infarction, lethal coronary hear disease, coronary revascularization) in the absence of clinical manifestations. MATERIAL AND METHODS: Meta-analysis of the results of studies on prognostic implications of coronary arteries calcinosis was made with standardized risk ratio as a metameter. The meta-analysis included tests for systemic error related to publishing primarily positive results and data heterogenicity. RESULTS: Overall risk ratios for cardiovascular complications ranged from 2.1 to 9.3 for different degrees of coronary artery calcinosis. CONCLUSION: Calcium index is an independent risk factor of complications of cardiovascular diseases.

Aged↗
PubMed2006

[The technologies of genetic engineering in treatment of chronic lower limb ischemia].

The article contains experimental data on angiogenesis stimulated by plasmid containing the angiogenin gene. After the introduction of the gene construction, the number of capillars in the chorion-allantois membrane increases 2 to 3 times; in an ischemized limb of a rat it increases by 20 to 30%. Intramuscular administration of genetic engineering construction to patients with chronic lower limb ischemia improved the patients' condition, consisting in an increase in painless walking distance and ankle-brachial index, as well as in trophic defect healing and the betterment of muscular perfusion. Positive effects were noted after 2 to 4 weeks of treatment and remained during 6 to 24 months. There were no side-effects, except low grade fever during 1 to 2 days.

Adenoviridae↗
PubMed2004

[The CELO-ANG recombinant avian adenovirus with human angiogenine gene inducing neovascularization in the anterior tibial muscle of rat].

The CELO recombinant avian adenovirus carrying the gene coding the human angiogenine (ANG) synthesis was obtained. Expression of the angiogenine gene was shown in the LMH cell culture after infection with the CELO-ANG virus. The ability of CELO recombinant adenoviruses to carry out the delivery and expression of alien genes in muscle cells was demonstrated in experiments with laboratory animals (Wistar line rats). The induced neovascularization in rat muscles after the animals were administered the CELO-ANG viruses was shown.

Angiogenesis Inducing Agents↗
PubMed2003

[Genetic engineering potential and perspectives in the management of critical ischemia].

The paper presents a new approach to management of lower limb critical ischemia which implements recent advances in molecular biology and genetic engineering technologies. A new original compound incorporating angiogenin gene was developed to activate neoangiogenesis processes after injection into living tissues. Experimental data evidence a potential efficacy of new method for complex management of critical ischemia.

Animals↗
PubMed2002

[Indications for carotid endarterectomy and its outcomes].

The paper analyzes a correlation between the sonographic and morphological characteristics of the structure of atherosclerotic plaques and the severity of cerebrovascular insufficiency. This significantly expands indications for surgical treatment in patients with carotid atherosclerosis. In the authors' opinion, not only the degree of carotid stenosis, but also the structure of a plaque is an important criterion for assessing indications for surgical treatment. The outcomes of carotid endarterectomy are comparatively evaluated in relation to the mode of carotid plastic repair. A role of intraoperative cerebral oximetry is shown.

Aged↗
PubMed2000

[Analysis of the annual open Russian competition for the best scientific student work in medical science].

For over 5 years, the I. M. Sechenov Moscow Medical Academy has been the basic Institute for holding the open Russian competition for the best scientific student work in medical sciences. The Academy has developed a methodological basis of this competition, which allowed the practical use of its organizational forms by the areas of informational support, evaluation of works, awards, office work. The authors' skills in presentation have become an original educational component in addition to usual expert estimation of works and afforded to obtain knowledge of progress in basic science and different problems in the organization of researches. The original competition organizing system has raised the popularity of the competition and the annual number of participants from different medical institutes and stimulated youth's interest in researches.

Competency-Based Education↗
PubMed1998

Cell lineage in marine nematode Enoplus brevis.

Early cleavages of the marine nematode Enoplus brevis are symmetrical and occur in synchrony. At the 2- to 16-cell stages, blastomeres are indistinguishable. The progeny of blastomeres was investigated by intracellular injections of fluorescent dyes and horse radish peroxidase. One blastomere of the 2-cell embryo gives rise to a compact group of cells occupying about half of an embryo. The border between labeled and unlabeled cells differs in each embryo dividing it to anterior-posterior, left-right or intermediate parts. At the 8-cell stage, one blastomere gives rise to only endoderm, whereas the other blastomeres produce progeny that form multiple cell types, including nerve, muscle and hypoderm cells, in various proportions. Thus the fates of the blastomeres of early E. brevis embryos, with the exception of the endoderm precursor, are not determined. The process of gastrulation in E. brevis is very similar to that in Caenorhabditis elegans and other nematodes. At the beginning of gastrulation, the 2-celled endoderm precursor lies on the surface of embryo and then sinks inwards. After labeling of cells on the ventral side (near endoderm precursor) at the beginning of gastrulation, their progeny differentiate predominantly into body muscles or pharyngeal cells of the first stage larva. Cells that are located more laterally give rise mainly to neurons. The dorsal blastomeres differentiated principally into hypoderm cells. Our study suggests that a precise cell lineage is not a necessary attribute of nematode development.

Animals↗
PubMed1992

Cyclic changes of membrane conductivity in fertilized and activated eggs of teleost (Misgurnus fossilis) and their relation to the cell shape.

Oscillations of membrane ionic conductivity, with a period similar to cell cycle duration, were observed in fertilized and activated loach (Misgurnus fossilis) eggs. In cleaving eggs the decrease in conductivity coincided with mitosis. Synchronously with the oscillations of membrane conductivity in activated as well as in fertilized eggs, rhythmic changes in blastodisc shape occurred. The blastodisc rounded up during the period of increasing membrane conductivity and flattened while conductivity decreased. Scanning microscopy of fertilized and activated eggs revealed differences in the surface relief of rounded and flattened blastodiscs.

Animals↗
PubMed1991

Ca2+ as a messenger of dorsal--ventral polarity formation in frog (Rana temporaria) eggs.

Three methods of Ca2+ administration were used to influence the location of the grey crescent and the dorsal lip of blastopore in R temporaria eggs, ie a Ca2+ microinjection into the subcortical cytoplasm, egg pricking in high Ca2+ solutions and Ca2+ ionophore A23187 microinjection and application. The treatments all induced grey crescent and dorsal lip of blastopore formation near the Ca2+ administration site. Inositol trisphosphate injections gave similar results. Colchicine injections into the eggs inhibited the appearance of both natural and Ca(2+)-induced grey crescents.

Animals↗
PubMedDate not supplied

[Comparative embryology of nematodes and the law of embryo similarity].

Two types of embryonic development can be distinguished within nematodes, with a variable (Enoplia) or invariant (remaining species) cleavage. In the case of invariant cleavage two main variants of cell lineage are presented in nematodes, with the posterior (Rhabditea) or anterior (Dorylaimida) localization of endoderm material at the two-cell stage. This classification is in a good agreement with some modern nematode taxonomy and it is supported by molecular phylogeny studies. The variable cleavage is plesiomorphic. Traditional concept of "mosaic" cleavage is not applicable for nematodes as inductive interactions and a regulation of experimental interventions are usual attributes of any mode of nematode development. The representatives of order Rhabditida have almost identical cell lineage, but at the same time they have strong interspecific differences in mechanisms of ooplasmic segregation any early inductive interactions. The diversity of geometric patterns in the early cleavage, often at the level of individual random variations, is a usual characteristic of nematodes including species with the invariant cleavage. Thus, the early stages of nematode development are evolutionary very flexible, but at the course of embryonic development similarity of different species is progressively increased up to the uniform morphogenetic stages. The dynamics of variation in nematode development contradict to the von Baer's law but are in an agreement with the modern "hourglass model" (Doboul, 1994; Raff, 1986).

Animals↗
PubMedDate not supplied

[Calculating the intrinsic growth rate: comparison of definition and model].

It was shown that well known equation r = ln[N(t2)/N(t1)]/(t2 - t1) is the definition of the average value of intrinsic growth rate of population r within any given interval of time t2-t1 and changing arbitrarity its numbers N(t). The common opinion considering the equation as suitable only for exponentially growing population was found to be incorrect. The fundamentally different approach is based on the calculation of r within the framework of demographic model, realized as Euler - Lotka equation or population projection matrices. However this model requires simultaneous realization of several assumptions improbable for natural populations: exponential change in population size, stable age structure and maintaining constant age-dependent birth and death rates. The calculation of r by definition requires the data on the dynamics of population numbers, whereas calculation on the basis of the model requires the demographic tables of birth and death rate, but not the population numbers. With the example of American ginseng it was shown that evalution of r by definition and model approaches could produce opposite results.

Models, Theoretical↗
PubMedDate not supplied

[Changes in the dorsoventral polarity in frog eggs (Rana temporaria) under the influence of Ca2+ injections. The conditions for effecting a response].

The effect of local injections of Ca2+ solutions into Rana temporaria eggs during the period from fertilization to 1st cleavage division was studied. In most cases, microinjection of 2-5 nl of 1-20 mM Ca2+ solution into subcortical cytoplasm determined formation of the grey crescent (and the dorsal blastopore lip) at the site of injection. Injection of 0.1 mM Ca2+ or Ca(2+)-free solutions had no effect on the formation of the dorso-ventral axis. The effect of Ca2+ is more pronounced when the injection is made into vegetal part of the egg, close to the boundary between pigmented and non-pigmented zones, than into animal-equatorial part. Injections made during the 0.10-0.15 period of the first cell cycle produced greater effect than those made during the 0.40-0.45 period of the same cycle.

Animals↗
PubMedDate not supplied

[Emergence of contraction waves on the surface of fertilized frog eggs under the effect of inositol triphosphate].

It was shown that the injection of the membrane messenger-myo-inositoltrisphosphate into frog eggs provokes the propagation of surface contraction waves. Such waves are not accompanied by the changes of membrane potential. We have analyzed the spatial-temporal characteristics of observed waves and have compared them with the data from models for diffusion and autocatalytic mechanisms of wave propagation.

Animals↗