[en] ²⁴Na-labelled sodium chloride was used in determining changes in rabbit eyes burned with sodium hydroxide or with hydrochloric acid. The labelled compound distribution showed that alkali burns resulted in more significant alterations than acid burns and that the equinormal hydroxide solutions were 4 to 8 times more potent than the corresponding acid solutions. The tracer method was proved highly useful for the quantitative assessment of changes in the intraocular system and highly promising for the estimation of significance of functional changes caused by local injuries. (L.O.)

[en] The penetration of intravenously injected [⁸⁶Rb] Cl into intraocular fluids and individual eye tissues was studied in the rabbit. The radioactivity of samples of whole blood and plasma, anterior and posterior aqueous, central and peripheral cornea, iris and lens, was measured at five different intervals after intravenous injection of the radioisotope. The dynamics of [⁸⁶Rb] penetration are compared with previous results on [²⁴Na]. (author)

[en] Standard strips of chromatographic paper soaked with ²²NaCl were applied to the cornea of experimental rabbits. During the 1 min contact nearly 10% of radioactivity passed from these strips into the cornea. External gamma counters were used and the aqueous flow was determined according to the half-time of ²²Na clearance. The values found showed that normal rabbits were in agreement with data found previously with other methods. A decrease of aqueous flow in burned eyes was noticed in animals burned with sodium hydroxide. The possible clinical uses of this method are briefly discussed. (author)

No abstract available

[en] Short communication

[en] Salt loads (0.17 or 0.34 mmol Na⁺; 6 M NaCl solution labelled with ²⁴Na) were administered into the amniotic fluid of 7-day-old chick embryos. ²⁴Na distribution in the embryonic blood, amniotic and allantoic fluids was measured in 1, 2, 4, 8, 12 and 24 h intervals to assess the kinetics of salt load movements in particular egg compartments. The aim was to estimate the efficiency of the embryonic homeostatic apparatus to maintain ionic balance inside th embryonic body. The Na⁺ concentration in the amniotic fluid was expected to rise after salt loading by about 275 and 400 mM, respectively. More than 10% of the salt dose per ml appeared in the embryonic blood 2 h after salt load administration while only 0.2% were found in the urine (collected as allantoic fluid). The maximal rise of ²⁴Na activity in the blood of salt-loaded embryos reached 11 to 12% of the dose which corresponded to an increase in Na⁺ concentration by 19 and 41 mM, respectively. The maximum of ²⁴Na activity appeared in the allantoic fluid with a delay of several hours and indicated an increment of Na⁺ concentration by 6% and 9% of the dose per ml in the case of salt-loaded embryos. The Na⁺ concentration in the allantoic fluid (urine) never exceeded that in the blood. The final Na⁺ activity (estimated in the blood 24 h after salt loading) was equal to 5% of the dose per ml in both cases, indicating a persistent elevation of Na⁺ concentration by 8.6 and 17.2 mM, respectively. (author). 1 fig., 2 tabs., 8 refs

[en] A new method is described of measuring ocular hydrodynamics using a short-time contact application of ²²NaCl to the corneal surface and following its subsequent clearance by means of external gamma counters. Clearance of ²²NaCl reflected the aqueous outflow by conventional and uveoscleral routes. Sodium diffusion into the ocular lens, vitreous body and retina did not significantly interfer with the rate of aqueous outflow. In the present study authors investigated the sodium corneal permeability and its diffusion into different compartments of the enucleated rabbit eyes. During the followed interval of 60. min. the corneal radioactivity decreased, activity in anterior chamber aqueous, sclera, iris, ciliary body and choroid achieved maximal values, in ocular lens, vitreous body and retina radioactivity steadily increased. After corneal deepithelization a fourfold increase of ²²NaCl transcorneal permeability was observed. (author)

No abstract available

[en] Rabbit corneas were burned by standard dropping of sodium hydroxide or hydrochloric acid in four different concentrations, 1.0 N, 0.5 N, 0.25 N, and 0.1 N. After an interval of 10 minutes, paper strips soaked with ¹⁴C-glucose were stretched over the corneal surface and the amount of transferred ¹⁴C-glucose in various experimental groups was investigated. Alkali burns of all grades diferred from the acid burns by the enhancement of ¹⁴C-glucose penetration into the cornea and aqueous humor, the main increase being found in the former after 0.1 N and in the latter after 0.25 N sodium hydroxide burn. The second experiment was performed on two groups of enucleated rabbit eyes, the first with normal and the second with deepithelized corneas. Corneal deepithelization facilitates penetration of ¹⁴C-glucose and its content in deepithelized eyes is four times higher than in the normal ones. (author)

[en] Radioselenium concentration and excretion was studied after administration of ⁷⁵Se-labelled selenite to male rats during ontogeny. The concentration of radioselenium in individual organs decreases with increasing age. The largest differences between young and adults were in the quantity and quality of excreted substances. During 2 h after the administration of 20 μmol selenite/kg young rats excreted 2.4% of the dose, essentially in the urine only, whilst adults excreted a total of 11%, distributed equally in breath and urine. The part excreted as methylated metabolites was 0.1% of the administered dose in young and 6.3% in adult rats. These results support the hypothesis that the differences in the sensitivity to the toxic action of selenite between young and adult rats can be due to ontogenic differences in selenium metabolism. (orig.)