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Iu A Krasnikov

Publications and source records attributed to Iu A Krasnikov.

18 recordsLinked to original sources
PubMed1998

[Reaction of melanocytes in vertebrate retina to the exposure to constant magnetic field].

The influence of a constant magnetic field (strain 40 kA/m) on retina pigmentary cells of grass frog (Rana temporaria) and grey pigeon (Columba livia) eyes was investigated. Changes in the number and length of melanocytes appendixes were noticed accompanied by formation of thickenings in which melanosomes sized from 0.1 to 0.5 micron are moving. It is established that magnetic properties of eye retina pigmentary cells depend on the presence of Fe3+ in melanin. A theoretical model of paramagnetic receptor has been elaborated, according to which the induction of a magnetic field, formed by melanocyte, makes of the order 100 pT1. This value well compares with the size of magnetic field of a nervous impulse (120 pT1), extending throughout a nervous fibre of the frog sciatic nerve (Wikswo et al., 1980). This allows to suggest a possible unsynaptic way of transferring the information about the perceived magnetic field.

Animals↗
PubMed1988

[Venous sinuses of the dura mater of the bird brain].

By means of corrosive, injection and tracheoscopy methods venous formations of the brain have been studied in 19 species of birds--endemical for Far East--from 12 orders. Four types of the venous sinuses structure have been distinguished in the dura mater: the first type of the structure is specific for birds that live an inactive and quiet life (blue rock pigeon, Ussuric pheasant, Tetrastes bonasia, domestic hen). The second type of the sinus structure occurs in birds, that sharply change the speed and height of their flight (Otus bakkamoena). The most manifested changes in the sinus structure are noted in waterfowl and diving birds, that spend much time in flight, in dendrocolaptidae and in day predaceous birds; in them the longitudinal sinus forms a rhombus.

Animals↗
PubMedDate not supplied

[The relief of the luminal surface of the sinuses in the mammalian cranial dura mater].

In Mammalia with different types in organization of blood outflow in the dura mater venous sinuses: vertebral (tiger), jugular (fur-seal, cat, rabbit) and mixed (rat, dog, man) the internal surface relief of these sinuses has been studied. The total plan of the relief in all the species studied is principally the same. It is characterized with presence of visually determined macro-relief structures: Pacchionian bodies, trabeculae, bars, eminences and excavations in places, where the sinuses fuse, initial folds (micro-relief) and, at last, formations composed by the nucleus and the external membrane of endotheliocytes (ultra-relief). The micro-relief depends on the type of the venous outflow from the brain. In the animals with the jugular type of the outflow the longitudinal folds are more expressed; in the animals with the vertebral type--there occur folds with transversal orientation. For the representatives with the mixed type--multilayered elastic carcass is specific. At the same time, the development degree of the micro-relief with a similar type of blood outflow is different. The relief of the luminal surface of the longitudinal venous sinus of the mammalian dura mater is supposed to be determined by presence of extravascular formations, by the muscular structures tonus, by construction of the wall elastic carcass and by activity of the luminal part of the external membrane of endotheliocytes.

Animals↗