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Biomedical subjects

A I Deev

Publications and source records attributed to A I Deev.

At least 19 recordsLinked to original sources
PubMed1999

[Physicochemical aspects of cataract genesis].

Based on their own studies and the data available in the literature, the authors consider the physicochemical aspects of cataract genesis. Emphasis is laid on the role of oxidative stress in this diseases. It is suggested that one of the key mechanisms of cataract genesis is the exhausted lenticular potential and oxidative stress, resulting in the formation of products that enhance lenticular photo lesion and imbalance of cyclonucleotide- and Ca(2+)-dependent cascade systems of regulation, which leas to impaired cAMP-dependent protein phosphorylation. Decreased phosphorylation of lenticular fiber proteins reduces their solubility and results in their sorption on the cell membranes, resulting in progressive impairment of the regulatory membrane placement. Light scattering on the folded membrane surfaces in the lenticular fibers is considered to be a main cause of lenticular opacity in cataract.

Animals↗
PubMed1991

[Parameters of lens protein fluorescence quenching in early stages of hereditary cataract].

Several physico-chemical parameters of lenses were investigated in IOR/Hab mice with hereditary cataract aged 4, 6, 8 weeks, i.e. at the stage preceding the development of cataract. The level of restored glutathione in the IOR/Hab lenses /2.0 mM/ was the lowest as compared to other lines but almost the same as in CBA/J /2.3 mM/. In the process of studying protein fluorescence quenching in cortex homogenates by nitrate anions a significant increase of the quenching constant was discovered in IOR/Hab mice: 10.4 M-1 in four-week animals and up to 32.3 M-1 in eight-week animals. The data obtained suggest that a progressing growth of the quenching constant in line IOR/Hab lenses is related to a decreased density of the protein negative charge resulted from their decreased phosphorylation.

Animals↗
PubMed1991

[Increase of accessibility of murine lens protein fluorophores to water in the development of radiation-induced cataract].

The accessibility of tryptophanyl fluorophores in crystalline proteins to water molecules was estimated by measuring the enhancement of the fluorescence of lens homogenates in 70% D2O as compared to 100% H2O. Assuming that two sorts of fluorophores exist in the proteins, one entirely accessible to H2O and D2O and the other--absolutely not, we have calculated the portion of either group in the protein fluorescence (alpha and 1-alpha, correspondingly). Measurement of murine lens homogenates fluorescence at different stages of radiation-induced cataract, initiated with total gamma irradiation in a dose 5 Gy have shown an increased accessibility of tryptophanyl for water with cataract development. At earlier stages of cataract (appearance of scattered dot opacities) the portion of water-accessible tryptophanyl increased from 0.14 to 0.18, i.e. by a factor of 1.3. The data obtained suggest that protein globules unfold in the coarse of cataract development.

Animals↗
PubMed1990

[Vitamin A and microsomal membranes: the effect of retinol deficiency on lipid microviscosity and phospholipid turnover in rat liver microsomes].

Studies with the use of the fluorescent probe pyrene revealed that vitamin A deficiency in maturing male rats results in the increased microviscosity of liver lipids. This effect seems to be due to changes in the lipid composition of microsomal membranes (increased cholesterol/phospholipid ratio and lowered polyunsaturated fatty acid content) as well as to the low level of retinol. Analysis of microsomal phospholipids labeled with [3H]palmitate and [14C]glycerol revealed that vitamin A deficiency accelerates the turnover of the glycerol skeleton but sharply decelerates that of fatty acid residues. It is concluded that the observed effect of retinol on the structural and functional properties of biological membranes is due to its ability to control the microviscosity and turnover of membrane lipids.

Animals↗
PubMed1990

[Increase of the negative charge of erythrocyte membrane proteins in hereditary neuromuscular diseases].

The parameters of erythrocyte ghost protein's fluorophores by nitrate's anions were studied in patients with various hereditary myodystrophy. In all the groups under examination the share of fluorophores accessible to a quencher was close to 1. In erythrocyte membranes of healthy donors the relevant constant quenchering was about 17.3 +/- 1.9 M-1 while those of patients were decreased by 3.1 (Duchenne's myodystrophy) and by about 2.0 (other forms of primary and secondary progressive muscular dystrophies). The most probable reason for the decreasing constant of quenchering is the increase of negative charges on the erythrocyte membrane proteins.

Erythrocyte Membrane↗
PubMed1989

[The fluorescence of mouse crystalline lenses at different stages of radiation cataract studied by synchronous scanning].

Fluorescence of intact lenses of F1 (CBA x C57BL6) mice at different stages of X-ray cataract induced by gamma irradiation (5.00 Gr) has been studied by synchronous scanning of fluorescence, the shift between emission and excitation wave lengths being 20 nm. The ratio between peek intensities of the nontryptophan and tryptophan fluorescence within the synchronous scanning spectra (K) has increased 3.5 times as much at the stage of singular dot-like opacities. K-parameter correlated with GSH level in the lenses (r = -0.9). According to the results achieved, K could be regarded as an informative indicator of the development of X-ray cataract at the stage previous to turbidity.

Animals↗
PubMed1988

[Discriminant analysis of methods for detecting the heterozygote carrier state for the Duchenne muscular dystrophy gene].

The authors used the procedure of a step-wise discriminant analysis for comparing the informative value of different methods for revealing heterozygotic carriers of the gene of Duchenne's myodystrophy by means of an analysis of the blood serum and physicochemical properties of erythrocytes in 11 mothers suffering from Duchenne's muscular dystrophy who were obligate (by the findings of a genealogical analysis) carriers of the gene of Duchenne's myodystrophy. Employment of a complex of four methods (determination of the constant of the rate of chloride-bicarbonate metabolism through the erythrocyte membrane, erythrocytic deformability, hemolytic stability of erythrocytes upon their heating at 55 degrees C, and analysis of the activity of serum creatine kinase) has increased 1.8-fold the rate of detecting heterozygotic carriers of the gene of Duchenne's myodystrophy as compared to the creatine kinase test.

Adult↗
PubMed1987

[Erythrocyte filterability of angina patients].

Erythrocyte filterability and its relation to erythrocyte volume, hemoglobin level and cholesterol/phospholipid ratio were studied in anginal patients. A 25% decrease in filterability and elevated erythrocyte cholesterol/phospholipid ratios were found in anginal patients, as compared to normal subjects. A close inverse correlation (r = -0.623) was demonstrated between erythrocyte filterability and cholesterol/phospholipid ratio. Mean erythrocyte volume and Hb levels were similar in anginal patients to those of normal subjects.

Adult↗
PubMed1987

[Crystalline lens induction of lipid peroxidation].

The level of lipid peroxidation products (LPP) was determined in the aqueous humor from the anterior chamber of patients with cataract and donor eyes. The content of LPP in senile cataract aqueous humor was shown to be significantly increased. To determine the possible mechanism of LPP increase in aqueous humor, human lenses at different stages of cataract as well as transparent human and rabbit lenses were incubated for 3 hours in 3.0 ml medium containing liposomes (0.5 mg/ml) prepared from phospholipids from the egg yolk and 0.14 M NaCl + 0.01 M TRIS-HCl buffer, pH 7.4). Corrections were made for phospholipid autooxidation. The level of LPP accumulation in the medium was determined by MDA assay. The rate of LPP production increased significantly in transparent lenses and in early senile cataract, as compared to controls and advanced (mature) cataracts. EDTA (1 mM), superoxide dismutase (114 u/sample), catalase (900 u/sample), chelated iron (III): Fe3+-ADP addition to the incubation medium depressed the level of LPP accumulation. This suggests the participation of Fe2+, O2-., H2O2 in the mechanism of LPP production in the lens. The induction of lipid peroxidation in the lens can be significant for leukotriene and prostaglandin synthesis in the eye.

Aged↗
PubMed1986

[Decomposition of H2O2 by human cataractous lenses].

It was shown that human lens opacity was accompanied by the decrease in the lens ability to cleave H2O2 (10(-4) M), added to the lens-surrounding medium. The rate of peroxide decomposition at the stage of mature cataract in isolated human lenses was 3.5 times lower than that of the control human lenses (transparent lens, initial cataract). Specific catalase inhibitor--3-amino,IH-1,2,4-triazole showed no significant influence on the rate of H2O2 cleavage. Reduced glutathione (10 microM) added to the lens incubation medium induced a sharp increase in the rate of H2O2 detoxication. The results indicate that reduced glutathione metabolism is of primary importance in the maintenance of anti-peroxide activity in the lens.

Amitrole↗