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Biomedical subjects

Iu A Kim

Publications and source records attributed to Iu A Kim.

15 recordsLinked to original sources
PubMed1990

[The effect of electromagnetic radiation on the membranes of the sarcoplasmic reticulum].

On the sarcoplasmic reticulum membranes has been shown that at temperature of Ca2(+)-ATPase activity change of dependence in the Arrhenius plot the microwaves (2450 MHz, specific absorption rate 12 w/kg) inhibit the ATP-hydrolase and Ca2(+)-transporting activity of Ca2(+)-ATPase. The effect of radiation exhibits within the narrow temperature range (approximately 1 degree C) and quantitatively corresponds to the decrease of Ca2(+)-ATPase activity caused by the decrease of temperature by 1.6 degrees C from 18 degrees C. The fluorescence intensity of naphthalene sulfonic probes reduces under the influence of microwaves at 18 degrees C.

Animals↗
PubMed1989

[Phospholipase A activity determines the rate of respiration of the mitochondria in hibernating animals].

The mechanisms for regulating the rate of respiration and oxidative phosphorylation in liver mitochondria from hibernating ground squirrels were studied. The microviscosity of the mitochondrial membrane in hibernating squirrels was found to be higher than that in active animals. Probably, a high microviscosity of the membrane causes a decreases in the rate of the transport of oxidation substrates into the mitochondrial matrix, which in turn may be one of the main reasons for the inhibition of mitochondrial respiration in hibernating squirrels. The activation of phospholipase A2 in a hypotonic medium results in the acceleration of the respiration and phosphorylation in the mitochondria from hibernating squirrels and is accompanied by the increase of the transport of substrates across the mitochondrial membrane. The inhibition of phospholipase A2 decreases Ca2+--induced acceleration of the transport of substrates and prevents the activation of the respiration and phosphorylation in a hypotonic medium.

Animals↗
PubMed1986

[Effect of pulse electromagnetic radiation on erythrocyte ghosts].

The pulse microwave radiation has been shown to increase the fluorescence intensity of 2-toluidinonaphthanene-6-sulfonate (2,6-TNS) and 1-anilinonaphthalene-8-sulfonate (1,8-ANS) built-in membranes of erythrocyte ghosts. In experiments with 2,6-TNS a frequency dependence of the effect of microwave radiation with maximum within the frequency range of 55-65 Hz has been found. It is suggested that the changes registered with fluorescent probes are induced by mechanical oscillations generated by the pulse microwave radiation.

Anilino Naphthalenesulfonates↗
PubMed1985

[Treatment of late radiation-induced skin ulcers with laser radiation].

The authors presented the results of laser stimulation of reparation processes in 25 patients with late radiation skin ulcers. Short-term therapeutic results turned out to be favorable in 18 (72%) patients, a complete cicatrization of ulcers was observed in 9 patients, significant improvement in 9.

Adult↗
PubMedDate not supplied

[Accumulation of paramagnetic centers in protein solutions exposed to UV-radiation].

It is shown that concentration of paramagnetic centres (PC) in UV-irradiated protein solutions at 77degreesK approximates the limiting value. The limiting number of PC (n) per one molecule is in direct proportion to that of aromatic amino acid residues in it n(sigma)=2+0,1 sigma. The formation of PC slopps because all the energy absorbed by aromatic amino acid residues is transfered to the radicals formed.

Alcohol Oxidoreductases↗
PubMedDate not supplied

[Specific modification of the alpha-subunit of Escherichia coli Rna polymerase by monomercuric derivative of fluorescein mercuric acetate].

The method for specific modification of Escherichia coli RNA polymerase by a monomercuric derivative of fluorescein--fluoresceinmonomercuracetate (FMMA)--a specific reagent for SH-groups of proteins is suggested. It is shown, that in conditions of equimolar FMMA/enzyme ratio the fluorescent label interacts preferantially with a single sulfhydryl group in alpha-subunit of RNA polymerase. The mercaptide bonding formation is followed by significant alterations of all spectral parameters of FMMA, but has no effect on the kinetic parameters (KB and k2) of RNA synthesis initiation nor does it lead to inhibition of the total RNA synthesis. The modification presented may be used in structural and topological investigations of RNA polymerase functioning.

Binding Sites↗
PubMedDate not supplied

[K+,H+ and Cl- fluxes across erythrocyte membrane irradiated with radio frequency electromagnetic fields].

The effect of 460 MHz microwave radiation on the ion-transporting properties of the isolated rat erythrocytes was studied with the use of K+, H+ and Cl(-)-selective electrodes. In comparison with the control cells kept at 0 degree C the most significant changes were observed in the K+ transport system. Particularly, microwave radiation (specific absorbed rate 280 W/kg) caused an increased loss of K+ during treatment and 2-fold decrease in the rate of K+ efflux from the irradiated erythrocytes, when the latter were incubated in the isoosmotic, unbuffered sucrose. The same changes were observed when the erythrocytes were conventionally heated up to 39 degrees C for 20 minutes. It is concluded that high levels of microwave radiation cause temperature-induced changes of the membrane structure resulting in alterations in potassium transport across the membrane.

Animals↗
PubMedDate not supplied

[Study of the effect of tegalide and bithionol on biological membranes using fluorescent probes].

Fluorescent probes were used to study structural changes in different membranes affected by gamma-radiation, protonophores and radioprotective agents, tegalide and bithionol. The preparations of the defined concentrations decreased the microviscosity of membranes, lowered the peaks and changed the temperature of phase transitions in liposomes from dipalmitoyl lecithin, and induced the output of Ca2+ from mitochondria. The effects depended on the radiation dose, the structure, concentration and lipophilicity of the preparation; protonophores produced a specific effect.

Animals↗