No abstract available

[en] Chinchilla rabbit lenses were irradiated using a ⁶⁰Co gamma source, and the changes in the transport activities, native weight, water content and dry weight were observed. The heads of rabbits were irradiated with doses of 10 and 20 Gy and functional changes occurring in the lenses were studied till the twenty-fourth week after the irradiation. The weight of the rabbit lens irradiated with a dose of 20 Gy significantly increased after the twelfth week and was maximal 16 weeks after irradiation when also cataracts were observed. The increased weight of lenses was caused by accumulation of water. The decrease in the dry weight of lenses preceded the period of visible cataracts. A decreased uptake of rubidium occurring during in vitro cultivation of lenses was the most sensitive marker for the changes caused by 20 Gy irradiation. It was significantly decreased as early as 8 weeks after irradiation, preceding the increased hydration of lenses by 4 weeks and the presence of visible cataracts by as much as 8 weeks

[en] The effects of ionizing radiation on the eye lids, the lacrimal gland, conjunctiva, cornea, iris, aqueous humour, intraocular pressure, vitreous humour, retina, and effects of whole-body irradiation on the eye are reviewed. (author)

[en] The changes are described of the crystalline lens induced by ionizing radiation. Clinical descriptions of cataracts caused by ionizing radiation are given, the threshold doses are listed of various kinds of radiation, and morphological and biochemical changes occurring in the irradiated lenses are explained. Possible protection of the crystalline lenses against ionizing radiation is mentioned

No abstract available

[en] The uptake was observed of ⁷⁵Se-selenite by the lens in Wistar strain rats in adult animals, in 17-day old rats kept with their mothers and in prematurely weaned rats. Also measured was the excretion of ⁷⁵Se by the lens of young and adult rats following incubation in the medium with radioselenium. The metabolites were analysed which were discharged by the lens containing ⁷⁵Se. In Brattleboro rats the uptake of ⁷⁵Se-selenite was also measured by the lens in young and adult rats. The uptake of ⁷⁵Se-selenite by the lens in young Wistar rats was found to be 1.6 times higher than by the lens of adult rats and the time course of the radioselenium uptake was slightly different. In the lens of prematurely weaned rats no significant difference was found in the uptake of radioselenium after 4 hours as compared with rats of the same age kept with their mothers. In homozygous Brattleboro rats, a higher uptake of ⁷⁵Se-selenite was found as compared with both young and adult heterozygous rats. The time course and the quantity of ⁷⁵Se efflux from the lens of young and adult Wistar rats differed significantly after 0.5 hour of pre-incubation. From metabolites containing ⁷⁵Se excreted by the lens following preincubation, glutathione selenotrisulfide and a not yet accurately determined fraction with a large share of radioactivity were isolated. The stated results provide yet more proof that selenium cataract is a manifestation of the ontogenic dependence of selenium metabolism in the lens and in the entire organism. (author). 4 tabs., 30 refs

[en] The uptake was studied of ³⁵S-cysteine by the lens of 14-day old and adult rats administered selenite in vitro and in vivo. The ontogenetic difference was determined in the uptake of ³⁵S-cysteine by the lens by a comparison with control groups. The uptake of ³⁵S-cysteine by the lens of young rats was more than treble. The effect of selenite on the uptake of ³⁵S-cysteine by the lens in vitro differed fundamentally in both age groups: in the young it was significantly reduced, in the lens of adult rats there was a significant increase. The uptake of ³⁵S-cysteine by the lens of rats following subcutaneous application of a cataractogenic dose of selenite on day 14 after birth was significantly reduced as early as day 1 after the application and continued to decrease till the onset of the cataract. Changes in ³⁵S-cysteine uptake by the lens were accompanied by reduced dry mass of the lens and increased hydration of the lens; the weight of the rats affected by selenite application was lower than that of rats in the control group. The main factor related to the higher sensitivity of the lens of rats in the early ontogenetic stage towards the cataractogenic effect of selenite could be insufficient protection against damage by oxidation. (author). 3 tabs., 30 refs

[en] One of the factors important for the maintenance of eye lens transparence is its water content which is controlled by the active transport of Na⁺ and K⁺ in the lens epithelium. In early phases of ontogenesis the rat lens is highly sensitive to various cataractogenic impulses (e.g., selenium induced cataract). In the present study, the question was studied of whether the ion turn-over in the lens changes during ontogenesis. Experiments were done on Wister rats of age span from 1 prenatal day to 2 years. The uptake was measured of ⁸⁶Rb which in the lens is transported analogously to K⁺. The rats were decapitated and extracted lenses were incubated in a MEM medium supplemented with bovine fetal serum and ⁸⁶Rb. ⁸⁶Rb uptake was expressed as a ratio of ⁸⁶Rb concentration in lens water to its concentration in the medium at the beginning of incubation. The ⁸⁶Rb was found to differ substantially in different age groups. A rapid drop in the uptake of ⁸⁶Rb was found in the lens in the critical period of lens development when the lens grows intensively and displays the highest sensitivity to exogenous metabolic disturbances. The developmental changes in the uptake of ions by the lens can reflect changes in the synthesis of both enzymes and crystallines. (author)

[en] The effect was observed in vitro of selenite on the uptake of ⁸⁶Rb by the lens in two weeks old and adult rats. Also measured was the uptake of ⁸⁶Rb by the lens in vitro in 30-days old rats with cataracts induced by the administration of selenite at day 14 after birth and in control animals of the same age. Selenite in a concentration of 0.4 mM and more caused an insignificant decrease in ⁸⁶Rb uptake by the lens in adult rats while in the lens of young rats the uptake decreased significantly already at concentrations lower by two orders. Lenses with cataracts took up significantly less ⁸⁶Rb than transparent lenses; body weight, the weight of the fresh lens and its dry mass decreased while the water content in the lens was higher as compared with control groups. (author). 2 tabs., 26 refs