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Biomedical subjects

V V Mezhevikin

Publications and source records attributed to V V Mezhevikin.

At least 19 recordsLinked to original sources
PubMed2005

Pre-biotic stage of life origin under non-photosynthetic conditions.

Spontaneous assembling of a simplest bacterial cell even if all necessary molecules are present in a solution seems to be extremely rare event and from the scientific standpoint has to be considered as impossible. Therefore, a predecessor of a living cell has to be very simple for providing its self-assembling and at the same time it should be able of progressive increase in complexity. Now phase-separated particles, first of all micelles, are put forward as possible predecessors of living cell. According to the offered working concept only phase-separated particles possessing autocatalytic properties can be considered as predecessors of living cells. The first stage of evolution of these phase-separated autocatalytic systems is the appearance of pre-biotic metabolism providing synthesis of amphiphiles for formation of capsules of these systems. This synthesis is maintained by the energy of a base reaction being a component of a planet-chemical cycle. Catalytic system providing functioning of pre-biotic metabolism is based on multivariate oligomeric autocatalyst, which reproduces itself from monomers, penetrating the particles from the outside. Since the autocatalyst realizes random polymerization then a collection of other oligomers possessing different catalytic functions is produced. In the paper the functioning of multivariate oligomeric autocatalyst in flow reactor is analyzed.

Catalysis↗
PubMed2003

An alternative approach to solar system exploration providing safety of human mission to Mars.

For systematic human Mars exploration, meeting crew safety requirements, it seems perspective to assemble into a spacecraft: an electrical rocket, a well-shielded long-term life support system, and a manipulator-robots operating in combined "presence effect" and "master-slave" mode. The electrical spacecraft would carry humans to the orbit of Mars, providing short distance (and low signal time delay) between operator and robot-manipulators, which are landed on the surface of the planet. Long-term hybrid biological and physical/chemical LSS could provide environment supporting human health and well being. Robot-manipulators operating in "presence effect" and "master-slave" mode exclude necessity of human landing on Martian surface decreasing the level of risk for crew. Since crewmen would not have direct contact with the Martian environment then the problem of mutual biological protection is essentially reduced. Lightweight robot-manipulators, without heavy life support systems and without the necessity of returning to the mother vessel, could be sent as scouts to different places on the planet surface, scanning the most interesting for exobiological research site. Some approximate estimations of electric spacecraft, long-term hybrid LSS, radiation protection and mission parameters are conducted and discussed.

Electricity↗
PubMed2003

Systematic approach to life support system analyses and integration.

This paper is devoted to the consideration of possible viewpoint on CELSS development and design. If the aim to create practically applicable CELSS is accepted then the task to optimize the process of CELSS research and development in terms of minimum cost, hours, maximum applicability, scientific contribution, etc. becomes actual. Requirements of applicability and scientific significance are synergetic since understanding of general properties of CELSS gives an ability to create CELSS for different applications. To accomplish the task three main groups of parameters have to be optimized: i) configuration and operating parameters of developing CELSS itself; ii) organizational management of research and development of CELSS; iii) features of an area where CELSS is planned to be used (space missions, terrestrial applications, or biosphere investigation) and where requirements to CELSS characteristic come from. Given paper is a brief review presented some attempts to arrange mentioned above into some set of formalized and interacting criteria, and some progression of research stages derived from these criteria.

Ecological Systems, Closed↗
PubMed2001

Life as a set of matter transformation cycles: ecological attributes of life.

An approach to searching for extraterrestrial life on the base of "autotroph" concept of the origin of life is presented in the paper. According to this concept the origin of life took place in three stages. The first stage was developed inside the global geochemical cycle in which the turnover of different chemical transformations was implemented by solar radiation and/or heat energy of bowels of the Earth. At the second stage, after the autocatalytic systems have emerged these systems evolved as a result of "natural selection" by autocatalysis parameters up to emergence of special inheritance systems that drastically improved the autocatalysis parameters. The best in terms of autocatalysis parameters were the autocatalysis systems based on phase-separated particles where complex structures can form not only on the basis of covalent interactions. Such autocatalysis systems can emerge only in liquid in a certain range of temperatures and pressures. At this stage the geochemical cycle complicated involving new substances. At the third stage the evolution involved improvement of inheritance systems resulting in formation of the modern type of genetic apparatus. This concept formed the basis to consider approaches to experimental modeling of major aspects of the origin of life and to outlining some general features of life that can extend the sensitive horizon of searching for extraterrestrial life.

Biological Evolution↗
PubMed2000

Evaluation of optimal configuration of hybrid Life Support System for Space.

Any comprehensive evaluation of Life Support Systems (LSS) for space applications has to be conducted taking into account not only mass of LSS components but also all relevant equipment and storage: spare parts, additional mass of space ship walls, power supply and heat rejection systems. In this paper different combinations of hybrid LSS (HLSS) components were evaluated. Three variants of power supply were under consideration--solar arrays, direct solar light transmission to plants, and nuclear power. The software based on simplex approach was used for optimizing LSS configuration with respect to its mass. It was shown that there are several LSS configuration, which are optimal for different time intervals. Optimal configurations of physical-chemical (P/C), biological and hybrid LSS for three types of power supply are presented.

Ecological Systems, Closed↗
PubMed1996

BIOS-4 as an embodiment of CELSS development conception.

Any attempt to create LSS for practical applications must take into account the possibility of castastrophic consequences if the problem of LSS reliability and stability is not solved. An integrated conception of CELSS studies development as a possible way to increase its reliability is considered. The BIOS-4 facility project is developed in the context of the conception. Three principles of highly effective experimental CELSS facility design are proposed. Some details of BIOS-4 design and its exploitation features are presented.

Ecological Systems, Closed↗
PubMed1996

Perspectives of different type biological life support systems (BLSS) usage in space missions.

In the paper an attempt is made to combine three important criteria of LSS comparison: minimum mass, maximum safety and maximum quality of life. Well-known types of BLSS were considered: with higher plant, higher plants and mushrooms, microalgae, and hydrogen-oxidizing bacteria. These BLSSs were compared in terms of "integrated" mass for the case of a vegetarian diet and a "normal" one (with animal proteins and fats). It was shown that the BLSS with higher plants and incineration of wastes becomes the best when the exploitation period is more than 1 yr. The dependence of higher plants' LSS structure on operation time was found. Comparison of BLSSs in terms of integral reliability (this criterion includes mass and quality of life criteria) for a lunar base scenario showed that BLSSs with higher plants are advantageous in reliability and comfort. This comparison was made for achieved level of technology of closing and for perspective one.

Bacteria↗
PubMed1994

Indications and counterindications for applying different versions of closed ecosystems for space and terrestrial problems of life support.

Different versions of manned closed ecosystems (CES) based on photosynthesis of unicellular and/or higher plants and chemosynthesis or bacteria are considered. Different versions of CES have been compared for applying them on Earth, Moon, Mars and Venus orbital stations, for Mars missions and planetary stations as well as to provide high-quality life in extreme conditions on the Earth. In microgravity [correction of mycrogravity] we recommend CES with unicellular organisms based on photosynthesis or chemosynthesis (depending of the availability of the light or electric energy). For the planetary stations with Moon gravity and higher CES with higher plants are recommended. Improvement of indoor air quality by CES biotechnology is considered.

Bacteria↗
PubMed1983

[Measurement of the intensity of erythropoiesis based on the RNA content of erythrocytes].

The relationship between RNA content in erythrocytes and the erythropoiesis rate was studied at varying exposures as a result of which a simple method for erythropoietic activity testing was proposed. It consists in the measurement of ribonucleic acid content in erythrocytes of mice with a decreased erythropoiesis after administration of the test sample. Erythropoietic activity is determined from the magnitude found. The method suggested is marked by simplicity and higher sensitivity and thus may be applied in clinical medicine and research.

Animals↗
PubMed1982

[NADPH- and ATP-dependent luminescence of extracts from luminous bacteria].

It was shown that the luminescence of extracts prepared from luminous bacteria is stimulated by NADPH and ATP without FMN or long-chain aliphatic aldehydes, which are routinely used for producing luminescence of extracts from luminous bacteria in vitro. In these extracts an aldehyde factor, a natural analog of aliphatic aldehydes, is synthesized. The enzymatic system involved in maintaining the luminescence of NADPH and ATP is probably not coupled with the functioning of NAD(P)H: FMN oxidoreductase which has been supposed to participate in luminescence processes in vivo. It is assumed that both aldehyde factor synthesis and reduction of endogenous analog of FMN, natural substrates of bacterial luciferase, are due to the functioning of the same metabolic pathway.

Adenosine Triphosphate↗
PubMed1981

[Obtaining purified erythropoietin from rabbit plasma].

A scheme of preparing partly purified erythropoietin from rabbit blood plasma is offered. The factor of purification is about 25000. Erythropoietin was purified by ion exchange chromatography on DE-32 cellulose, affinity chromatography on phytohemagglutinin-P and by gel filtration through Ultragel ACA-44. The specific activity of erythropoietin thus obtained was about 75-100 units per mg protein. The preparation may be used for exploring the regulation and differentiation of red blood cells and as an initial material for obtaining high-purified erythropoietin..

Animals↗
PubMed1977

[Effect of hypoxemia on the erythropoietic activity of organs during perfusion].

Hypoxemia (45-minute) influence in vivo on erythropoietic activity of the kidney, liver, spleen, and sternum was studied by normoxemic perfusion of the isolated organs. The erythropoietic activity proved to increase after 6-hour perfusion of the liver; this confirmed the participation of this organ in the extrarenal secretion of the erythropoietic factor.

Animals↗