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Biomedical subjects

A V Kuznetsov

Publications and source records attributed to A V Kuznetsov.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Metabolic compartmentation and substrate channelling in muscle cells. Role of coupled creatine kinases in in vivo regulation of cellular respiration--a synthesis.

The published experimental data and existing concepts of cellular regulation of respiration are analyzed. Conventional, simplified considerations of regulatory mechanism by cytoplasmic ADP according to Michaelis-Menten kinetics or by derived parameters such as phosphate potential etc. do not explain relationships between oxygen consumption, workload and metabolic state of the cell. On the other hand, there are abundant data in literature showing microheterogeneity of cytoplasmic space in muscle cells, in particular with respect to ATP (and ADP) due to the structural organization of cell interior, existence of multienzyme complexes and structured water phase. Also very recent experimental data show that the intracellular diffusion of ADP is retarded in cardiomyocytes because of very low permeability of the mitochondrial outer membrane for adenine nucleotides in vivo. Most probably, permeability of the outer mitochondrial membrane porin channels is controlled in the cells in vivo by some intracellular factors which may be connected to cytoskeleton and lost during mitochondrial isolation. All these numerous data show convincingly that cellular metabolism cannot be understood if cell interior is considered as homogenous solution, and it is necessary to use the theories of organized metabolic systems and substrate-product channelling in multienzyme systems to understand metabolic regulation of respiration. One of these systems is the creatine kinase system, which channels high energy phosphates from mitochondria to sites of energy utilization. It is proposed that in muscle cells feed-back signal between contraction and mitochondrial respiration may be conducted by metabolic wave (propagation of oscillations of local concentration of ADP and creatine) through cytoplasmic equilibrium creatine and adenylate kinases and is amplified by coupled creatine kinase reaction in mitochondria. Mitochondrial creatine kinase has experimentally been shown to be a powerful amplifier of regulatory action of weak ADP fluxes due to its coupling to adenine nucleotide translocase. This phenomenon is also carefully analyzed.

Adenosine Diphosphate↗
PubMedDate not supplied

Functional coupling as a basic mechanism of feedback regulation of cardiac energy metabolism.

In this review we analyze the concepts and the experimental data on the mechanisms of the regulation of energy metabolism in muscle cells. Muscular energetics is based on the force-length relationship, which in the whole heart is expressed as a Frank-Starling law, by which the alterations of left ventricle diastolic volume change linearly both the cardiac work and oxygen consumption. The second basic characteristics of the heart is the metabolic stability--almost constant levels of high energy phosphates, ATP and phosphocreatine, which are practically independent of the workload and the rate of oxygen consumption, in contrast to the fast-twitch skeletal muscle with no metabolic stability and rapid fatigue. Analysis of the literature shows that an increase in the rate of oxygen consumption by order of magnitude, due to Frank-Starling law, is observed without any significant changes in the intracellular calcium transients. Therefore, parallel activation of contraction and mitochondrial respiration by calcium ions may play only a minor role in regulation of respiration in the cells. The effective regulation of the respiration under the effect of Frank-Starling law and metabolic stability of the heart are explained by the mechanisms of functional coupling within supramolecular complexes in mitochondria, and at the subcellular level within the intracellular energetic units. Such a complex structural and functional organisation of heart energy metabolism can be described quantitatively by mathematical models.

Adenosine Triphosphate↗
PubMedDate not supplied

[The prevalence of the intravenous use of psychoactive preparations in Nizhegorod Province and the possible ways to prevent HIV infection among the users].

The number of users of intravenous drugs (UID), altogether from 35,000 to 25,000 persons, was determined by the method of coefficients. The analysis of 130 anonymous questionnaires, including 75 street questionnaires (61%) and 51 questionnaires (39%) distributed among UID in narcological and infectious hospitals showed that out of 130 respondents 60% underwent hospital treatment. The study revealed that most of the questioned users used crudely made opiates, 48 (37%) out of 130 persons made injections with used syringes and needles (in younger age groups the proportion of such UID amounted to 63%). 70% of the respondents used individual injection instruments (in a group of persons older than 25 years they amounted to 90%). The conclusion was made on the necessity of introducing a school program on the healthy mode of life and information programs on the prevention of the spread of infection among UID with due regard to different age groups, as well as training outreach workers for disseminating information on the prophylaxis of HIV infection among UID.

Adolescent↗
PubMedDate not supplied

[The transfer of foreign DNA by rabbit spermatozoa into hamster eggs].

Capacitated rabbit sperm was incubated with pCMVlacZ plasmid and then used to fertilize hamster oocytes liberated from zona pellucida. After treatment with DNase I, these oocytes were examined for the presence of exogenous DNA by PCR. DNA of pCMVlacZ was not found in oocytes after simple incubation with male gametes. The presence of DNA was recorded in the experiments where the sperms were treated with DMSO and subjected to heat shock prior to fertilization.

Animals↗
PubMedDate not supplied

[The prevention of HIV infection and other blood-contact diseases among intravenous narcotic users in Nizhniy Novgorod within the framework of the Harm Reduction program].

The results of the development and realization principles of the project on the decrease of harm, envisaging work in three directions (the determination of the technology of using drugs, the exchange of syringes/needles and other accessories, as well as laboratory examination for the presence of antibodies to HIV, hepatitis B and hepatitis C viruses and consultations of narcologists). 1075 injecting drug users took part in this project. Out of 611 participants filling-in the questionnaires, 338 persons underwent tests for HIV and 3 of them were found to be HIV-infected; out of 305 persons screened for the presence of markers of hepatitis B virus, positive results were obtained in 98 (32% of cases); in 218 (65%) out of 335 persons antibodies to hepatitis C virus were found (49 persons, i.e. 14%, had hepatitis C registered in the medical history and in the rest antibodies were detected for the first time). The preventive program of the decrease of harm was assessed as effective.

Adolescent↗
PubMedDate not supplied

[The mobile vector method for genetic transformation of animals].

Experimental data on transgenic animal production using transfected sperm are reviewed. Pathways for further improvement of the method for increasing the frequency of transgenic organisms are proposed: modification of the saccharophosphate skeleton and DNA ends; use of nucleic exchange enzymes and directed oligonucleotides; use of adhesive sequences (MAR elements), ori replication, and transposable elements within the transgenes; development of the embryos selection; the use of gene targeting elements; and the use of various DNA conformations. The promising use of spermatozoa as a noninvasive system of gene delivery in transgenesis and prenatal gene therapy are outlined.

Animals↗
PubMedDate not supplied

[Study of the transfer of foreign genes into mussel Mytilus Galloprovincialis Lam. eggs by spermatozoa].

The possibility of transferring exogenous DNA into eggs by mussel Mytilus galloprovincialis Lam. sperms both with the use of certain methods of transfection and without them was studied. The efficacy of egg fertilization by sperms treated with foreign DNA and the development of larvae at early stages of embryogenesis were evaluated. Negative effects of the contact between mussel sperms and exogenous DNA on fertilization and subsequent development were noted. The proportion of developing larvae decreased with increasing DNA concentration and sperm exposure. Transfer of plasmids pCMVlacZ and pMTbGH into eggs was observed in group crosses. With the use of PCR, foreign DNA sequences were found in the larvae at the stage of veliger 48 h after fertilization. An intense signal was recorded after sperm electroporation in 10% DMSO.

Animals↗