[Damage and functional recovery of the mouse retina after exposure to ionizing radiation and methylnitrosourea].

The eye retina consists of terminally differentiated cells that have lost their ability to proliferate. The death of these cells leads tothe loss of sight. The mice retina is characterized by relatively high resistance to radiation, which is provided by its ability to repair damage caused by environmental factors.

[The estimation of age-related sensitivity of the retinal pigment epithelium of Japanese quail (Coturnix japonica) to the light damage].

The effect of blue light damage (445-455 nm, 4 J/cm2) to retinal pigment epithelium (RPE) subcellular structures was investigated in 4 age risk groups (9, 25, 40 and 52 weeks) of Japanese quail Coturnix japonica by light and electron microscopy. The indicator of biological aging of RPE was age-related accumulation of lipofuscin granules: 5-6-fold increase in their quantity increasing by 5-6 times in quails at 52 weeks. The main photo-induced changes observed after 24 h of the photo radiation were located in the blood-retinal barrier, such as loss of homogeneity of Bruch's membrane, disorganization of basal processes, deformations of the nuclei and mitochondria shapes.

[Deceleration of cataract development in rats under the action of N-acetylcarnosine and D-pantethine mixture].

The effect of a mixture of N-acetylcarnosine and D-pantethine (1 : 1, m/m) on UV-A induced cataract in rats was studied. It is shown that instillation of a 5% mixture into the eyes or intraperitoneal injections (25 or 150 mg/kg) inhibit the formation of cataracts, starting from 82nd day of the experiment (p < 0.03), after which the protective effect of the mixture significantly increases (p = 0.

[RPE melanosomes bind A2E fluorophore of lipofuscin granules and products of its photooxidation].

The ability of melanosomes from human, bovine and frog retinal pigment epithelium cells (RPE) to bind A2E fluorophore of RPE lipofuscin granules and products of A2E photooxidation is investigated. RPE melanosomes are found to bind A2E molecules themselves as well as the molecules formed after A2E irradiation by visible light. In our experiments single melanosome was able to bind up to 0.

[Experimental study of the influence of disturbing factors and chaperone-like drugs on cataractogenesis].

A comparative experimental study of biomicroscopic appearance of lenses in cataracts of different genesis (age-related, ultraviolet and other radiation-induced or combined) has been performed on animals (mice). It is shown that identical lens opacification can be provoked by aging (endogenous factor), as well as ultraviolet and other radiation exposure (exogenous physical factors). The only differential sign is the severity of the damage.

[Carotenoids of the human eye in prenatal and early postnatal development].

The review deals with the role of carotenoids in the formation of the structural and functional differentiation of the macula--the area of the highest visual acuity of the human retina. The review also presents the data on detection of carotenoids (lutein) in the vitreous body of the human eye during its prenatal development and discusses their possible role in the development of the retina, particularly in relation to differentiation of the macular area. Macular dystrophy has been considered till recently as senile pathology.

[Galactic heavy charged particles damaging effect on biological structures].

A concept of the radiation risk of the manned interplanetary flights is proposed and substantiated. Heavy charged particles that are a component of the galactic cosmic rays (GCR) have a high damaging effect on the biological structures as great amount of energy is deposited in heavy particle tracks. The high biological effectiveness of heavy ions is observed in their action on cell genetic structures and the whole organism, including the brain structures.

[Experimental study of influence of different damaging factors on lens. Report 3. Changes of lens protein composition].

Using differential electrophoresis protein composition of lens major proteins in hybrid mice F1 (C57B1XCBA) with cataracts of different etiology (senile, ultraviolet, radioactive and combined ultraviolet-radioactive exposure) was studied Changes that may be specific for cataract caused by aging, ultraviolet and/or gamma-irradiation were not revealed in water-soluble and water-insoluble protein fractions.

[Experimental study of influence of different damaging factors on lens. Report 2. Features of microscopic lens changes].

Microscopic lens changes are studied in mice (F1C57B1XCBA) depending on age and after ultraviolet (UV), gamma-irradiation and their combination. In all animals compared to young 3-months animals nonspecific changes due to aging were revealed: microvacuoles in cytoplasm of fiber cells, flattening of epithelial cells and nuclei fragmentation, swelling and confluence of cortical layer cells in anterior and posterior subcapsular zones. In epithelial cells the following changes were noted: nuclei polymorphism, cavities in a cell layer formation of multilayered structures of fibroblast-like cells and cell desquamation.

[Experimental study of influence of different damaging factors on lens. Report 1. Features of biomicroscopic changes].

Comparative study of lens biomicroscopy in cataract of different etiology (senile, ultraviolet, radioactive and combined ultraviolet- radioactive exposure) is performed in experiment on animals (mice). Lens opacification pattern was showed to be similar in aging as an endogenous factor and ultraviolet (UV) and radioactive exposure as exogenous physical factors. Specificity of these factors is expressed in degree of damage only.

[Mechanisms of radioresistance in terminally differentiated cells of mature retina].

Retinopathy of animals is induced by many agents damaging DNA. This fact shows that DNA lesions may initiate retinal degeneration. The aim of our work was to study the effects of gamma and proton irradiation, and methylnitrosourea (MNU) on mice retina.

[Comparative study of aging, UV treatment, and radiation on cataract formation].

Four randomized groups of male mice F1 (C57Black/CBA) were investigated: a) UV-irraidated (UV-A, 15 min daily during 9 months, dose 5.6 + 1.2 W/m2), b) gamma-rays irradiated (2 Gy), single, c) influence for combination of UV- and gamma-rays treatment, d) aging.

[Studies on the conformational state of the chromophore group (11-cis-retinal) in rhodopsin by computer molecular simulation methods].

Based on computer simulation methods, the molecular dynamics of the rhodopsin chromophore group (11-cis-retinal) has been analyzed. The molecular dynamics has been traced within a 3-ns time interval; thereby 3 x 10(6) discrete conformational states of opsin and rhodopsin were compared and analyzed. It was shown that, within a short time of about 0.

[Retina radioresistance: whole-body exposure of mice to gamma-irradiation induces the retina DNA damage, accumulation of p53 protein followed by DNA repair rather than the apoptosis].

Whole-body irradiation of mice with gamma-rays at 14 Gy causes DNA single and double strand breaks effectively repaired later. p53 is accumulated during the repair period. There is still some amount of DNA breaks 48-72 hours after the irradiation.

[Investigation of the mechanisms of crystallin aggregation induced by pulsed laser UV irradiation at 308 nm].

The results of the investigations of photoaggregation of the main eye lens proteins alpha-, beta- and gamma-crystallins and the model protein carbonic anhydrase in response to pulsed irradiation by a XeCI laser at 308 nm in the wide range of pulse energy densities (w) and pulse repetition rates (F) have been reviewed. A nonlinear dependence of aggregation efficiency on the values of w, F, and the concentration of protein solution was found. A theoretical model that qualitatively describes the experimental results was developed.

[Chaperon-like anticataract agents, the antiaggregants of lens crystallin. Communication 4. Study of the effect of a mixture of di- and tetrapeptides on a prolonged rat model of UV-induced cataract].

There is a potential of therapeutic action on certain stages of caractogenesis, in particular on the aggregation of water-soluble proteins of cytoplasmic lens fiber cells, giving rise to insoluble protein complexes. The effect of a combined preparation (N-acetyl carnosine and D-patethine), acting by the chaperon-like mechanism, was studied in vivo on a prolonged rat model of UV-induced cataract. The use of the combined preparation consisting of a mixture of peptides of N-acetyl carnosine and D-patethine in a ratio of 1:1 as ocular instillations and intraperitoneal injections could slow down the development of UV-induced cataract in vivo.

[Search for chaperon-like anticataract agents, the antiaggregants of lens crystallin. Communication 3. Possibilities of a follow-up of caractogenesis processes on a prolonged rat model of UV-induced cataract].

To study the mechanisms of action of new-generation anticataract drugs, it is necessary to have an accessible and adequate model of age-related cataract. A model of UV-induced cataract is pathogenetically closest to that of age-related cataract. A prolonged rat model of UV-induced cataract developing within 10 months is proposed; the clinical features of UV-induced cataract have been established at different stages of its development.

[Like anticataract agents, the antiaggregants of lens crystallin. Communication 2. Study of the impact of chaperon-like (protective) activity of short-chain peptides on the rate of UV-induced aggregation of betaL-crystallins by eximer laser].

UV-induced aggregation of betaL-crystallin, one of the major lens proteins, was studied under its pulse radiation with XeCl laser at a wavelength of 308 nm. Unlike the in vitro tested dipeptides L-carnosine, N-acetyl carnosine, D-panthetine, and particularly their combination, the so-called new chaperon was demonstrated to slow down the rate of photoaggregatin of beta-crystallin. The new chaperon, a mixture of D-pathethine and N-acetyl carnosine was ascertained to protect a mixture of betaL- and alpha-crystallins from UV-induced aggregation to a greater extent than D-pathethine or N-acetyl carnosine used alone.

[Search for chaperon-like anticataract drugs, the antiaggregants of lens crystallins. Communication. 1. Chaperon-like activity of N-acetyl carnosine dipeptide: in vitro study on a model of ultraviolet-induced aggregation of betaL-crystallin].

Aggregation ofcrystallins, the lens proteins, is one of the basic stages of cataract formation. Among the protein aggregation models used to study the molecular mechanisms of the initial stages of lenticular opacity, UV-induced aggregation of betaL-crystallin is most close to the in vivo conditions. The carnosine derivative N-acetyl carnosine has been shown to be effective in inhibiting the UV-induced aggregation of betaL-crystallin.

[Detection of carotenoids in the vitreous body of the human eye during prenatal development].

Carotenoids were found for the first time in the vitreous body of human eye during the fetal period from week 15 until week 28. Their maximum content was timed to week 16-22. No carotenoids were found the vitreous body of 31-week fetuses, as well as adult humans, which corresponds to the published data.

Molecular dynamics of rhodopsin and free opsin: computer simulation.

Computer simulation was used to perform a comparative study of the molecular dynamics of rhodopsin containing the chromophore group (11-cis-retinal) and free opsin. The molecular dynamics were followed over a time interval of 3000 psec; a total of 3 x 10(6) discrete conformational states of rhodopsin and opsin. The presence of the chromophore group in the chromophore center of opsin was shown to have significant effects on the immediate protein environment of the chromophore and the conformational state of the cytoplasmic domain, but to have virtually no effect on the conformational state of the intradisk domain.

[Molecular dynamics simulation of dark-adapted rhodopsin and free opsin].

Molecular dynamics simulation was carried out for the rhodopsin protein to investigate its conformational changes in respect to inclusion of 11-cis retinal chromophore. Molecular dynamics calculations were performed within the time frame 3000 ps. Totally, 3 X 10(6) configurations ofrhodopsin and free opsin were analyzed and compared.

[Antibodies to retinal S antigen in the tear and serum as an indicator of the nature of a course of endogenous uveitis in children].

Antibodies (IgM and IgG) to retinal S antigen were studied by enzyme immunoassay in the tear (n = 135) and blood serum (n = 221) samples taken from 45 children with chronic endogenous uveitis during a follow-up (for 6 months to 5 years). The studies have confirmed the early evidence that detection of serum autoantibodies may be used for the diagnosis of autoimmune and infectious-and-autoimmune uveitis, the verification and prediction of renal alterations, risks for lesions in the second eye in unilateral uveitis and prerecurrence in bilateral uveitis. Criteria for detecting antibodies to lacrimal S antigen were developed.

Characteristics of the photoconversion of rhodopsin in the early stages of photolysis.

Low-temperature spectrophotometry was used to study the primary stages of rhodopsin photolysis. A digitonin extract of rhodopsin was irradiated at -155 degrees C with blue light of wavelength 436 nm. The stage of the bathorhodopsin --> lumirhodopsin conversion was accompanied by the simultaneous formation of several products.