[Proliferative activity and cell differentiation during the period of intensive growth of the iris, ciliary body and pupillary sphincter in rats]. / Proliferativnaia aktivnost' i differentsirovka kletok v period intensivnogo rosta raduzhiny, tsiliarnykh skladok i sfinktera zrachka u krys.

The duration of the cell cycle in the sphincter pupillae and in the inner and outer neuroepithelia of the iris and ciliary body was studied. The four-day old rats were injected H3-thymidine and three-day old animals were administered H3-dopa to be processed for autoradiography. Cells of sphincter and of both neuroepithelia of the iris have the doubling time of 9.2--9.8 days, whereas the doubling time of cells of neuroepithelia of the ciliary body reaches 5.3--5.9 days. All pigmented epithelia of the iris-ciliary body complex synthesize melanin with the same intensity despite their specific differentiation. The most differentiated smooth muscle cells localized at the outer surface of the sphincter have almost half a melanin synthetic activity as compared with that of more deeply laying cells. Mitotic and H3-thymidine labelled cells were observed in all the areas of the sphincter. The data obtained were interpreted in terms of possible compatibility of both processes in smooth muscle cells of the iris; the synthesis of contractile proteins and the mitotic activity. The cell proliferation and differentiation of the structures in question were regarded as processes being regulated independentely at the stage studied.

[Formation and reorganization of the early photoreception area in the eyes of sturgeon embryos and prelarvae. Radioautographic study]. / Vozniknovenie i preobrazovanie oblasti rannei fotoretseptsii v glazakh zarodyshei i predlichinok osetrovykh. Radioavtograficheskoe issledovanie.

A study of the development of eye retina in sturgeons (Acipenser güldenstädti and A. stellatus) by means of autoradiography has shown that during embryogenesis the cells of the high light sensitivity region complete the cycle of proliferation prior to the stage 29, what corresponds to the completion of proliferation of the retina cells in anurans and mammals, rather than at the stage 33, as was considered previously on the basis of the light microscopy morphological studies of differentiation. The cells of definitive retina begin to complete the cycle of proliferation at the stage 35 and the mass completion occurs at the stage 37. Some parameters of mitotic cycle were determined in the cells of definitive retina at the stages 34 and 37 and they proved to be similar with the corresponding parameters of the retina cells in anurans. The time of G2 period equals 2.5 hrs, that of S period 14 hrs and the whole mitotic cycle lasts 21.5 hrs. The transformation of the retina of high light sensitivity region in the definitive retina proceeds, mainly, by means of migration of the cells in this zone from the zone of intensive proliferation surrounding the high light sensitivity region. This transformation proceeds by means of morphological rearrangement of metamorphosis type.