[Chaperone activity of alpha-crystallin for Ca-pump of the skeletal muscle sarcoplasmic reticulum during stress and adaptation].
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Adaptation, Physiological↗
Biomedical subjects
M A Babizhaev
Publications and source records attributed to M A Babizhaev.
[Lipoperoxidase activity of carnosine and carcinine].
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Antioxidants↗
[Potentiation by promethazine of hypotensive effects of adrenergic drugs on intraocular pressure].
Experiments including previous installations of promethazine (pipolphen) into the conjunctival sac followed by the topical administration of beta-adrenergic blocker timolol or a sympathomimetic drug isoptoepinal (adrenaline) have been performed on 24 rabbits (48 eyes). The substantial changes in the action mode of the mentioned drugs as the enhancement of their hypotensive effect on the intraocular pressure (IOP) have been demonstrated under the performance of the above mentioned procedure. When applied after promethazine instillations, timolol induced significantly increased outflow facility of the aqueous humor that was not usually noted in the cases of timolol topical instillations without a pretreatment of the eye with promethazine. The similar increased hypotensive effect on the IOP was noted for adrenaline when it has been used after promethazine treatment. The possible mechanisms underlying the changes in pharmacological activities of the investigated adrenergic drugs are discussed.
Adrenergic beta-Antagonists↗
[Oligomerization of water soluble proteins of rabbit crystalline lens under the action of diamide].
The study has examined the effects of the SH-oxidizing agent diamide (Diazane dicarboxylic acid bis-(N,N-dimethyl-amide)) on the water-soluble portion of proteins from rabbit lenses. The dialyzed protein extracts were incubated for 1-1.5 hrs with various concentrations of diamide. Treatments were monitored for alterations in sulphydryl contents, gel filtration and gel electrophoresis profiles of proteins. The response to 2 mM diamide treatment for 1 hr consists of rapid oxidation (up to 40%) of protein-bound sulphydryl groups accompanied by an appearance of polypeptides with apparent molecular weights. The protein with molecular weight of 29 kilodaltons was shown to be involved in cross-linking. The linkages in the dialyzed water-soluble lens polypeptide fraction induced by diamide may be reduced by GSH (10 mM) treatment of protein extract. The main target of oxidative insult induced by diamide in the water-soluble proteins of the lens is probably the superficially localized sulphydryl groups of crystallins. Our observations suggest that the described oxidative system of proteins may be a useful tool for cataract research.
Animals↗
[Effect of carnosine on intraocular pressure].
It has been demonstrated in experiments on non-anesthetized rabbits that conjunctival injection of carnosine (beta-alanyl 1-histidine) caused a decrease in normal intraocular pressure and reduced prostaglandin-induced ocular hypertension. The rapid onset of the pressure response and the absence of papillary dilation in rabbits treated with carnosine were observed. It is concluded that L-carnosine can be used as a potent drug for the prevention of reactive hypertension syndrome.
Animals↗
The antioxidative properties of carnosine, a natural histidine containing dipeptide.
The experimental results suggest that the antioxidative function of carnosine is one of the most important manifestations of its biological role. The ability of carnosine to interact directly with lipid peroxidation products was demonstrated. The effects of carnosine on partial restoration of lens transparency in dog eyes with senile cataract which is known to be caused by lipid peroxidation were demonstrated "in vitro" and "in vivo".
Animals↗
[Mechanisms of retinal damage in chloroquine retinopathy].
The paper presents the results of comparative electron microscopic, electrophysiological and biochemical studies of chloroquine effect on lipid peroxidation (LPO) both in vitro and in vivo (rabbits and rats). It has been shown that the progress of chloroquine retinopathy was not accompanied by the increment of the initial LPO level, and the use of ionol antioxidant did not protect the retina from the adverse effect of chloroquine. Besides, chloroquine was shown to suppress LPO in vitro. The results obtained substantiate the idea that LPO is not the primary mechanism in chloroquine retinopathy.
Animals↗
[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↗
[The chemical nature of the fluorescing products accumulating in the lipids of the crystalline lenses of mice with hereditary cataract].
The content of diene conjugates (lipid hydroperoxides) was shown to be significantly higher in lipids extracted from the lenses of mice with hereditary cataract than in the controls. The same holds true for characteristics of fluorescence of the end-product of lipid peroxidation. Two (low- and high-molecular weight) peaks were detected in chromatographic lipid profile of cataract lenses measured by fluorescence on Sephadex LH-20 column, whereas only one (high-molecular weight) peak was found in lipids from normal lenses. It was established that high-molecular weight fluorescent fractions corresponded to lipid components of lipofuscin-like pigments. NMR and mass spectrometry of low-molecular weight fractions suggested that they contained predominantly products of free radical oxidation of long chain polyunsaturated fatty acids (C22:6).
Animals↗
[Mechanisms of the effects of Ca2+ ions on lipid peroxidation].
Mechanisms underlying Ca2+ effects on lipid peroxidation (LPO) induced in liposomes (from egg yolk lecithin) and UFsomes (from linolenic acid, methyl linolenate) with the aid of O2- -system (Fe2+ + ascorbate) were studied. It was shown that stimulation of lipid peroxidation by low Ca2+ concentrations (10(-6)-10(-5) M) was due to its ability to release Fe2+-ions bound to negatively charged (phosphate, carboxylic) lipid groups (of licethin, linolenic acid), thus increasing the concentration of catalytically active Fe2+. The inhibitory effect of high Ca2+ concentrations was caused by its interaction with superoxide anion-radicals and was not observed in LPO-systems, independent of O2- generation (e. g. Fe2+ + cumol hydroperoxide).
Calcium↗
[Peroxidation crystalline lens damage--a possible cause of the development of traumatic cataract].
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Animals↗
[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↗
[Evidence of the oxidation of unsaturated fatty acids in cataracts].
Gas chromatography analysis with the use of an electron captured detector including preparation of the halogen-substituted derivatives of fatty acids is a useful tool for the detection of lipid peroxidation products both in vitro and in vivo. This technique was applied to determine the content of fatty acid oxy-derivatives in lipid samples of transparent and completely opaque human lenses. At the stage of mature cataract a significantly increased level of oxyproducts was observed in the lens lipid fraction. It was concluded that accumulation of polar oxygroups in the lipid bilayer of plasma membranes of lens fibres is a plausible cause of their damage in cataracts.
Cataract↗
[Accumulation of lipid peroxidation products in cataractous lenses].
A study was made of the content of lipid peroxidation products (LPP) in the lenses extracted during operations for cataract as well as in transparent human lenses. In a mature cataract, the elevated content of primary, secondary and end products of lipid peroxidation (diene and triene conjugates, Schiff bases) was revealed. The content of LPP was identical in different clinical patterns of a mature cataract (senile, traumatic, complicated), which points to the universal role of lipid peroxidation in lenticular opacity.
Animals↗
[Formation of complexes of superoxide anion radicals with Ca++].
It has been shown that Ca2+ can form complexes with superoxide anion radicals (O(-2)). The constant of this interaction is 3 10(4)-5.5 10(4) M-1s-1. Mg2+ and Zn2+ cations do not form complexes with O(-2). It is concluded that Ca2+ may be involved in the control of O(-2) content in the cell.
Calcium↗
[Diffusion properties of water in the human crystalline lens during cataract development].
Normal and cataractal decapsulated lenses of man were studied by NMR method-spin echo to obtain information concerning efficient coefficients of self diffusion, times of spin-spin relaxation of water protons (T2) and water content in the lens (c) at 25 degrees C in the course of cataractogenesis. It has been found that the values T2 and c at 25 degrees C are much higher in the nuclei of completely turbid lenses than in the transparent ones; the self-diffusion coefficients in the turbid lenses were also higher. At -9 degrees C a significant decrease of the content of undestroyed by frost (bound) water was observed at the stage of mature cataract as compared to transparent lenses. It is suggested that the most specific differences between the nuclei of transparent and completely turbid lenses are related to increased diffusion mobility of water molecules, apparently, at the expense of damaged plasmic membranes of the lens fibres noted during cataract development.
Cataract↗
[Results of combined use of taufon and timolol in the treatment of patients with open-angle glaucoma].
The effect of taufon and timolol maleate combination on intraocular pressure and ocular hemodynamics was studied in 44 patients (63 eyes) with primary open-angle glaucoma. Combined administration of these agents elevated almost twofold the fluid discharge efficacy coefficient and normalized Becker's coefficient in 68.6 percent of patients. The patients were followed up for 8 weeks. Taufon addition to timolol modified the action of this latter drug, normalizing the ocular hemodynamics.
Adult↗
[Photo damage to the eye in exposure to the radiation from a Nd:YAG Q-switching laser: the physicochemical structural changes to the crystalline lens and the vitreous body].
Structural changes in the lens and vitreous body exposed to short-pulse Nd:YAG Q-switching laser were under study. The laser was focussed in the lens nucleus or vitreous center plane. A pulse energy was 7.1-9.3 mJ, with a total of 75-100 pulses. Cataract development was induced via the formation of cavities with the guidance spot focal plane localized in the lens nucleus plane. When the focus was in the vitreous body and the laser operated in a similar energy mode, great numbers of small cavities rapidly formed, this evidencing a shock wave propagation. Specific and structural conformational changes in the lens and vitreous protein molecules were detected by nitrate quenching of the triptophane amino acid residue fluorescence. Laser exposure was found to reduce triptophanile availability for nitrates, this evidencing protein complexes aggregation (collapse); besides, laser exposure essentially increased the amino acid residue quenching constants, which fact pointed to a decreased density of the vitreous collagen and lens crystalline negative charges (increased hydratation). These findings permit a conclusion that the shifts connected with injury to the vitreous body, with macular edema, or with detachment of the retina after exposure to Nd:YAG laser may be due to collapse of the vitreous gel liquified components.
Animals↗