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Biomedical subjects

V A Moiseev

Publications and source records attributed to V A Moiseev.

At least 19 recordsLinked to original sources
PubMed2000

The use of 1H-NMR spectroscopy and refractometry for investigation of the distribution of nonelectrolytes of N-alcohol series between human red blood cells and extracellular medium.

Comparative analysis of 1H NMR spectroscopy and refractometry with respect to their application for investigating the distribution of nonelectrolytes of n-alcohol series (ethanol, 1,2-propanediol, glycerol) and polyethylene glycols (PEGs) with molecular masses of 400, 600, 1500 between human erythrocytes and extracellular medium was performed. The distribution coefficients (Q) for solutions of ethanol, 1,2-propanediol, glycerol, PEG-400, PEG-600 and PEG-1500 were obtained. The Q values decreased with the increase in the nonelectrolyte molecular mass from 1.23+/-0.12 for ethanol to 0.40+/-0.08 for PEG-1500 (1H NMR spectroscopy) and from 2.6+/-0.12 for ethanol to 0.23+/-0.03 for PEG-1500 (refractometry). It was shown that 1H-NMR high-resolution spectroscopy ensures more precise determination of Q values for nonelectrolytes with low molecular masses; for PEGs with high molecular masses, the accuracy of Q value calculation by this method was about 20%. On the contrary, refractometry can be used for investigating substances with high molecular masses; the error of Q value determination for solution of low-refractive substances, such as ethanol, may be more than 50%.

Electrolytes↗
PubMedDate not supplied

[Functional status of cryopreserved rat liver mitochondria].

Mitochondria from the rat liver have been frozen down to -196 degrees C under protection of dimethylsulfoxide, after which they were subjected to periodical increase and decrease in temperature (cycling) in the ranges of -105 degrees C to -196 degrees C or -135 degrees to -196 degrees C. There have been observed some non-lethal damages of mitochondria which were revealed in the decrease in the respiratory control and in the ADP/O ratio after the cycling. The damage rate increased with the increase of the number of temperature decrease-increase cycles. The damages were also greater in the case when the upper limit of cycling temperature was higher than the glass transition temperature of the freezing medium (Tg = -126 degrees C). The non-lethal damages of mitochondria are explained by the influence of electric fields, appearing in the frozen sample during the temperature increase or decrease.

Animals↗
PubMedDate not supplied

[Study of erythrocyte dehydration using spin labels].

Possibility of studying erythrocyte dehydration by ESR-spin probe is substantiated. Dehydration of erythrocytes in relation to osmolarity of sodium chloride solutions is investigated. The results are shown to agree with the data obtained by radioisotope method.

Body Fluids↗
PubMedDate not supplied

[Effect of freezing and thawing on the structure and function of cytochrome oxidase].

The effect of freezing-thawing on cytochrome oxidase from cattle heart was studied. The enzyme was characterized for its activity, absorption spectra, temperature perturbation differential spectra and conformational transitions. A decrease in the activity and conformational changes depend on the composition of the buffer system and the presence of potassium and sodium chlorides in the solution.

Animals↗
PubMedDate not supplied

[Study of the state of mitochondria at low temperatures by the ESR method].

Possible usage of ESR probe method for studying low temperature effect on structural and functional state of mitochondria is under study. It is shown that during freezing out of mitochondrial water there is sharp dehydration of intermitochondrial matrix and membrane thickening. The facts are given about damage of barrier function of the membrane at the moment of appearance of extramitochondrial liquid phase during thawing.

Animals↗
PubMedDate not supplied

[Possibility of controlling orthostatic instability in spinal cord injuries].

Hemodynamics were studied in 10 patients with high (cervical) spinal cord injury in a change to a vertical position. They were fitted with special antioverexertion gear (AOG) consisting of an abdominal, two thigh, and two knee inflatable rubber cuffs in which pressure of +50 mm Hg was produced. Measurements were taken every minute of arterial pressure, volumetric rate of blood flow in the upper limb (by venous-occlusion plethysmography), cardiac output and stroke volume (by body integral rheography); peripheral resistance and vascular resistance were calculated from a formula. Change of the patient to a vertical position without the use of the AOG was attended by a sharp fall in arterial pressure, stroke volume, and peripheral resistance and by marked tachycardia. Orthostatic collapse developed in the third-fourth minute. The use of the AOG prevented such a fall in the hemodynamic parameters which stayed on a higher level, this made it possible for the patients to remain in an erect position for 10 minutes and longer. These of the AOG in recommended in the first stage of training patients with sharply pronounced orthostatic instability.

Blood Flow Velocity↗
PubMedDate not supplied

[Hemodynamic changes during the orthostatic test in patients with spinal cord damage at different levels].

Hemodynamics were studied during orthostatic load on a special orthotable in 54 patients with different levels of spinal cord interruption. With the patient in a horizontal and then in a vertical position, the arterial pressure, pulse, volume rate of blood flow in the forearm, and the cardiac output were recorded every minute. The total resistance of the vessels was calculated. Absence of constrictor reactions in the lower half of the trunk was revealed in patients with a high level of spinal cord damage, due to whicorthostatic collapse developed within the first minutes after they had been placed in a vertical posture. The orthostatic stability of such patients may be somewhat improved by producing additional external pressure to the lower part of the trunk (with special suits) and by means of other forms of special training. Patients with the spinal cord damaged at a low level (below the sixth thoracic vertebra) tolerate a 10-minute orthostatic load quite satisfactorily.

Adolescent↗
PubMedDate not supplied

[The effect of temperature and concentrations of various substances on the microviscosity of erythrocyte cytosol].

EPR spin-probe method was used to investigate the dependence of erythrocyte cytosol microviscosity (ECM) on the concentration of different substances and temperature. The critical ECM value has been determined after reaching of which erythrocytes become destroyed. It is shown that this ECM value is reached at different NaCl concentrations depending on the temperature.

Cytosol↗
PubMedDate not supplied

[Structural and functional characterization of cytochrome oxidase encapsulated in liposomes in sodium chloride solutions].

The effect of NaCl concentration (0-2 M) on the absorption spectrum and enzymic activity of cytochrome oxidase built in lecithin liposome has been studied at 24 and 8 degrees C. It is shown that at 0,8 M NaCl concentration a conformational transition occurs that leads to the enzyme inactivation. The relationship between protein conformation and liposome state has been established.

Animals↗