Influência do uso tópico da ciprofloxacina a 0,3 por cento versus a 0,5 por cento, na regeneraçäo do epitélio corneano, em coelhas / Evaluation of the topical effect of ciprofloxacin eye drops (0,3 percent verus 0,5 percent) with controls on superficial epithelial corneal healing in rabbits

Este estudo compara, em coelhas, a influência do uso tópico de ciproflaxacina a 0,3//e a 0,5//, com controles, na cicatrizaçäo de defeitos epiteliais corneanos. Dentro das condiçöes desse estudo, conclui-se que a ciprofloxacina a 0,3//näo influencia na reparaçäo da lesäo, enquanto a ciproflaxacina a 0,5//retarda significativamente a cicatrizaçäo da área desepitelizada

Retinomotor movements in the frog retinal pigment epithelium: dependence of pigment migration on Na+ and Ca2+.

The ionic dependence of the screening-pigment migrations in the frog retinal epithelium (RPE) was quantitatively studied with eyecups incubated in media of different compositions. Typical migrations in response to light and darkness, equivalent to those observed in the intact animal, were fully accomplished and maintained for up to 6 hr by the isolated organ bathed in Ringer solution rich with O2. Pigment migration in either direction was completed under the appropriate illumination conditions at any time during the day, indicating that circadian influences, if present in the intact animal, can be overridden in the isolated organ by light or darkness alone. Pigment aggregation toward the dark-adapted position was inhibited by: (a) low external Ca2+, (b) high external Na+, and (c) drugs expected to increase the cytoplasmic levels of either Na+, or Ca2+, like ouabain, caffeine and the ionophore A23187. However, the inhibition caused by low Ca2+ did not occur if Na+ was also reduced in the incubation medium. On the other hand, an increase in the concentration of external Ca2+ or the addition of Co2+ to the normal Ringer facilitated pigment aggregation in the dark. Pigment dispersion to the light-adapted position was unaffected by any of the above conditions. This is the first report of full and stable pigment responses in the RPE of vertebrate eyes incubated under simple physiological conditions. The results seem to conciliate a discrepancy of previous reports on the Ca2+ dependence of RPE movements, and are compatible with current views on ionic mechanisms in analogous systems of intracellular transport.

[Proliferative activity of the pigment epithelium and regenerating retinal cells in Ambystoma mexicanum]. / Proliferativnaia aktivnost' kletok pigmentnogo épiteliia i regeneriruiushchei setchatki u Ambystoma mexicanum.

Cellular sources of retinal regeneration and proliferative activity of the cells taking part in retina restoration have been studied in axolotls using 3H-thymidine. The cells of ciliary-terminal zone proved to be the main source of retinal restoration. Besides these cells, the pigmented cells of the iris inner and outer layers and pigment epithelium cells can take part in this process. Morphological stages of retinal regeneration have been established and regular changes in the level of proliferation in different zones of regenerating retina have been found with respect to the stage of retina restoration. The high level of proliferative activity of the pigment epithelium cells found soon after the operation favoured the restoration of disturbed integrity of the pigment epithelium layer, the increase of cell density in it, the elongation of the pigment epithelium layer, the formation of processes, and, sometimes, the replenishment of regenerating retina.