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Biomedical subjects

V I Baranov

Publications and source records attributed to V I Baranov.

At least 19 recordsLinked to original sources
PubMed2006

Volume reflection of a proton beam in a bent crystal.

Volume reflection predicted in the mid-1980s by Taratin and Vorobiev has been observed for the first time in the interactions of a 70 GeV proton beam with a short bent crystal. Incident protons deviate from convex atomic planes in the bulk of the crystal as a result of coherent interaction with bent lattice around the tangency point of particle trajectory with a curved atomic plane. The deflection angle 2theta(R) was found to be (39.5+/-2.0) microrad, or (1.65+/-0.08)theta(c) in terms of the critical angle for channeling. The process has a large probability with respect to channeling and takes place in the angular range equal to the bend angle of atomic planes. It could possibly open new fields of application of crystals in high-energy particle beam optics.

Journal Article↗
PubMed2006

Intracellular changes in rat hepatocytes after intratracheal administration of highly dispersed silicon dioxide and uridine effects on these changes.

Rat hepatocytes were examined under electron microscope at early terms after intratracheal administration of highly dispersed silicon dioxide powder against the background of uridine treatment. Penetration of powder particles into hepatocyte cytoplasm, nuclei, mitochondria, and peroxisomes and development of bacteria in these cells were observed. Uridine reduced the destructive effect of powder on the organelles, increased glycogen content in hepatocytes, and inhibited the formation of capsulated bacterial forms in these cells.

Animals↗
PubMed2005

Multiple cellular antigen detection by ICP-MS.

There is a great need in cell biology for the simultaneous detection of many intracellular and extracellular proteins within single cells. Current optical methods based on fluorescence activated flow cytometry are difficult to multiplex. We have developed a novel application of ICP-MS-linked metal-tagged immunophenotyping which has great potential for highly multiplexed proteomic analysis. Expression of intracellular oncogenic kinase BCR/Abl, myeloid cell surface antigen CD33, human stem cell factor receptor c-Kit and integrin receptor VLA-4 were investigated using model human leukemia cell lines. Antigens to which specific antibodies are available and are distinguishably tagged can be determined simultaneously, or multiplexed. Four commercially available tags (Au, Sm, Eu, and Tb) conjugated to secondary antibodies enable a 4-plex assay assuming that the primary antibodies are not cross-reactive. Results obtained by ICP-MS were compared with data from FACS. ICP-MS as an analytical detector possesses several advantages that enhance the performance of immunoassays, which are discussed in detail. Although multiplexing using metal-conjugated reagents is in a very early stage of research and feasibility studies, it is already apparent that more than four antigens could be accurately detected simultaneously using the ICP-MS instrument.

Animals↗
PubMed2004

Ultrastructural and cytochemical changes in the respiratory compartment of the lungs in rats after combined treatment with fine silicon dioxide powder and uridine.

Electron microscopy and cytochemical study of alveolar tissue of rat lungs were performed at the early stage after intratracheal treatment with fine silicon dioxide powder. The preparation was administered to animals receiving or not receiving intravenous injection of uridine. Dust particles permeated the cytoplasm, mitochondria, and nuclei of cells in the air-blood barrier of the alveoli. Uridine decreased the severity of dust-induced damage to cells and increased intracellular glycogen content.

Animals↗
PubMed2002

[Coefficient of oxygen diffusion in fibers of the skeletal muscles].

The effective coefficient of oxygen diffusion in muscle fibers (DO2eff) calculated from measured values of O2 critical pressure, O2 intake and fiber diameter in different skeletal muscles in vertebrates turned to be equal to (0.9-1.8) x 10(-6) cm2/s, which is 11 to 33 times lower than O2 in water. In mature animals, DO2eff reaches this value after the fiber diameter has grown to the maximum. In embryos and developing species with thinner myofibers DO2eff is significantly lower. Variations in oxidative metabolism in the fiber do not change DO2eff. Temperature drop in the fiber by 10 degrees C reduces DO2eff by approximately 30%. Modeling of the oxygen regimes in skeletal muscles with low DO2eff demonstrated that increase of the size of the O2-rich interstitium from 9 up to 25% reduces the diffusive resistance to O2 on the way from the capillary to mitochondria by approximately 20% (1); in combined muscles hypoxic areas may appear in the center of fibers with a high O2 demand, particularly when diameters of these fibers are comparatively large (2); the volumetric blood flow in the muscle can be infinitely large and O2 pressure in veins can remain high (the so-called functional shunting).

Age Factors↗
PubMed2001

Reaction chemistry and collisional processes in multiple devices for resolving isobaric interferences in ICP-MS.

A low-level review of the fundamentals of ion-molecule interactions is presented. These interactions are used to predict the efficiencies of collisional fragmentation, energy damping and reaction for a variety of neutral gases as a function of pressure in a rf-driven collision/reaction cell. It is shown that the number of collisions increases dramatically when the ion energies are reduced to near-thermal (< 0.1 eV), because of the ion-induced dipole and ion-dipole interaction. These considerations suggest that chemical reaction can be orders of magnitude more efficient at improving the analyte signal/background ratio than can collisional fragmentation. Considerations that lead to an appropriate selection of type of gas, operating pressure, and ion energies for efficient operation of the cell for the alleviation of spectral interferences are discussed. High efficiency (large differences between reaction efficiencies of the analyte and interference ions, and concomitant suppression of secondary chemistry) might be required to optimize the chemical resolution (determination of an analyte in the presence of an isobaric interference) when using ion-molecule chemistry to suppress the interfering ion. In many instances atom transfer to the analyte, which shifts the analytical m/z by the mass of the atom transferred, provides high chemical resolution, even when the efficiency of reaction is relatively low. Examples are given of oxidation, hydroxylation, and chlorination of analyte ions (V+, Fe+, As+, Se+, Sr+, Y+, and Zr+) to improve the capability of determination of complex samples. Preliminary results are given showing O-atom abstraction by CO from CaO+ to enable the determination of Fe in high-Ca samples.

Journal Article↗
PubMed2000

Oxygen diffusion coefficient in isolated chicken red and white skeletal muscle fibers in ontogenesis.

Oxygen diffusion from medium to cultured isolated muscle fibers from red gastrocnemius muscle (deep part) (RGM) and white pectoralis muscle (WPM) of embryonic and postnatal chickens (about 6 months) was explored. The intracellular effective O(2) diffusion coefficient (D(i)) in muscle fiber was calculated from a model of a cylindrical fiber with a uniform distribution of an oxygen sink based on these experimentally measured parameters: critical tension of O(2) (PO(2)) on the surface of a fiber, specific rate of O(2) consumption by a weight unit of muscle fibers (;VO(2)), and average diameter of muscle fibers. The results document the rapid hypertrophic growth of RGM fibers when compared to WPM fibers in the second half of the embryonic period and the higher values of;VO(2) and critical PO(2) during the ontogenetic period under study. The oxygen D(i) in RGM fibers of embryos and 1-day chickens was two to three times higher than observed for WPM fibers. For senior chickens, the oxygen D(i) value in RGM and WPM fibers does not differ. The D(i) of O(2) in both RGM and WPM fibers increased from 1.4-2.7 x 10(-8) to 90-95 x 10(-8) cm(2)/s with an ontogenetic increase in fiber diameter from 7. 5 to 67.0 microm. At all stages the oxygen D(i) values in RGM and WPM fibers are significantly lower than the O(2) diffusion coefficient in water: for 11-day embryos they are 889 and 1714 times lower and for adult individuals 25 and 27 times lower, respectively. Why oxygen D(i) values in RGM and WPM fibers are so low and why they are gradually increasing during the course of hypertrophic ontogenetic growth are still unclear.

Animals↗
PubMed1999

PCR assay of DNA damage and repair at the gene level in brain and spleen of gamma-irradiated young and old rats.

The PCR amplification of fragments of transcribed (beta-actin, p53) and nontranscribed (IgE, heavy chain) genes in brain and spleen DNA from gamma-irradiated and unirradiated 2- and 28-month-old rats was studied. The amplification levels of fragments of these genes in DNA from old rats were substantially lower than those from young rats, which suggested that these gene fragments in old-rat DNA contained lesions blocking thermostable polymerase in PCR. The beta-actin and IgE gene fragments of spleen DNA from old rats exhibited a significantly higher level of lesions inhibiting Tth polymerase compared to analogous fragments of brain DNA from the same animals. DNA from the tissues of gamma-irradiated rats showed the amount of damage inhibiting amplification to be dependent on animal age and the postirradiation time before DNA isolation. As judged from the changes in the amplification level of gene fragments, there was no preferential fast repair of lesions in the actively transcribed gene beta-actin compared to the nontranscribed gene IgE (heavy chain) in the brain and spleen of gamma-irradiated young and old rats. The amplification results suggest that equal amounts of DNA lesions were repaired in the brain of both old and young rats during the first 0.5 h of the postirradiation time (fast-repair phase), whereas in the subsequent postirradiation period over 5 h (slow-repair phase), the efficiency of damage elimination in the brain DNA of old rats was markedly lower. As for the spleen tissue, the elimination of lesions blocking Tth polymerase was much lower in old gamma-irradiated animals for both of the repair phases.

Actins↗
PubMed1999

Estimation of DNA damage and repair in tissues of gamma-irradiated animals using the polymerase chain reaction.

Damage and repair of DNA isolated from brain and spleen of gamma-irradiated rats were assayed using the polymerase chain reaction (PCR) method. Damage produced by gamma-radiation in DNA in cells of these tissues of exposed animals was shown to block PCR with the Tth polymerase. This blockage was noted as a decrease in the level of amplification of the fragments of a transcribed gene (beta-actin), an inducible gene (p53), and a nontranscribed one (IgE, heavy chain). The most pronounced decrease in the amplification of the gene fragments was observed on the DNA template isolated from rats immediately after their gamma-irradiation. When DNA was isolated 0.5-5.0 h after exposure, the amplification level was restored, no matter what transcription activity the genes possessed. For comparison, we used in PCR in vitro gamma-irradiated DNA as well as DNA templates with UV-damage, 8-oxy-2;-deoxyguanosine (8-O-dG), and apurinic sites (AP-sites). We found that gamma- and UV-irradiated DNA as well as DNA with AP-sites blocked the Tth polymerase in PCR, whereas 8-O-dG did not effect the level of PCR amplification of gene fragments. The observed changes in the level of PCR amplification of genes on the DNA template from tissues of gamma-irradiated animals are due to various radiation-induced lesions capable of blocking the Tth polymerase. The results show that the PCR method can be used for assaying the integral DNA damage and repair in cells from irradiated animals.

Animals↗
PubMed1995

[The blood supply to the skeletal muscles of chickens in ontogeny].

During chicken growing, the m. soleus and m. pectoralis fibers become early 10-fold larger, the number of capillaries increase, they elongate and the blood velocity diminishes. A linear relation between PO2 and number of capillaries was revealed in the course of postnatal growth. The arterio-venous oxygen difference increased in the m. soleus' vascular bed and decreased in the m. pectoralis' one.

Aging↗
PubMed1991

[The oxygen diffusion coefficient in isolated skeletal muscle fibers].

The oxygen diffusion coefficients in isolated skeletal muscle fibres of Baikal seal and grayling, white rat, chicken were calculated on the basis of experimentally determined curve of dependence of the O2 consumption on pO2 and the radius of the fibres. In all the cases, the diffusion coefficient was smaller in the fibres than in water. The oxygen diffusion coefficient was increased during embryogenesis and postnatal period in chicken. The influence of different parameters of the oxygen transport and of properties of different fibres on the values of the oxygen diffusion coefficients, are discussed.

Animals↗
PubMed1991

[Determining the level of yttrium oxide-coated silicon nitride in the air of the work area].

To measure the concentrations of yttrium-oxide-coated small-dispersed silicon nitride plasma powder, the air was aspirated at the amount of 10-15 litres per min through the AFA-XP filter. The filter was limed in a platinum crucible, the residuum being alloyed with Na2CO3, Na2B4O7, NaNO3 in ratio 10:5:1. The alloy was transferred into solution in which the silicon content was assessed through reactions with ammonium molybdate, and yttrium--through reactions with arsenaso III. The sensibility rate for silicon was at 0.07 mg/m3.

Air Pollutants, Occupational↗
PubMed1989

Gene expression in a cell-free system on the preparative scale.

A cell-free system for preparative gene expression is described. It is composed of DNA-free Escherichia coli extract and added plasmid DNA; coupled transcription-translation proceeds with a continuous flow of the feeding solution containing nucleoside triphosphates and amino acids. The system works at a high constant rate for tens of hours. The yield of synthesised proteins after 20-50 h is hundreds of micrograms from 1 ml of the reaction mixture. Electrophoretic analysis of translation products confirms synthesis of proteins of the expected molecular mass.

Adenosine Triphosphate↗