[Provisionality phenomenon in the histo- organo- and systemogenesis].

This review summarizes the results of the study of the provisionality phenomenon in the development of the organs of the urinary system (mesonephros, metanephros) in viviparous (human, rat) and oviparous (bird) amniotes, human organs of mixed origin (pituitary, ovary, stomodeum) reparative regeneration of supporting tissues (in humans and Syrian hamster), morphogenesis of primary hepatic cancer developing against the background of superinvasive opisthorchiasis. It is shown that during the development of tissues and organs, the stages of provisional and definitive histo- and organogenesis could be determined; saltatory mechanism is typical for embryonic organogenesis (formation of cartilaginous skeletal primordia, meso- and metanephrons) and foci of oncogenesis. Transformation zones of the type of tissue organization in the epithelium are located in the areas of contacts of the derivatives of different embryonic primordia. Mechanism of transformation of the epithelial layer of stomodeum and Rathke's pouch is provided by local activation of apoptosis and by the formation of the epithelial cells of a qualitatively new generation.

[The assessment of the regularity of the nephron anlage tubule formation on the basis of provisionality principle].

The study of the definitive kidneys of 94 human embryos and fetuses at 4.5 to 12 weeks of gestation, has demonstrated that the formation of the proximal nephron tubules resulted from the cellular proliferation in the area of transition of the capsule of the renal corpuscle into the tubular part of the nephron that occurs only after the completion of the segregation of the renal corpuscle and the distal tubule within the nephron anlage. The formation of the renal tubules in the nephron anlage seems to be determined phylogenetically, while the initial differentiation of the distal tubule is a provisional feature.

Limits on light-speed anisotropies from Compton scattering of high-energy electrons.

The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the European Synchrotron Radiation Facility's GRAAL facility constrains such anisotropies representing the first nonthreshold collision-kinematics study of Lorentz violation. When interpreted within the minimal standard-model extension, this result yields the two-sided limit of 1.6×10(-14) at 95% confidence level on a combination of the parity-violating photon and electron coefficients (κ(o+))(YZ), (κ(o+))(ZX), c(TX), and c(TY). This new constraint provides an improvement over previous bounds by 1 order of magnitude.

[Exposure to chloroprene as an occupational hazard (a cohort epidemiologic study)]. / K voprosu o kantserogennoi opasnosti khloroprena v usloviiakh proizvodstva (kogortnoe èpidemiologicheskie issledovaniie.

A cancer epidemiological study was conducted in chloroprene workers in Yerevan. In a cohort of male workers, the total morbidity rates for all tumor patterns were significantly lower (32%) than expected, which was attributed to the effect of "the healthy worker". Risk for hepatic tumor was 3.83 times the expected level among male operators of the chloroprene production equipment. A direct "dose-effective" correlation was established between liver cancer risk and length of record for occupational exposure to chloroprene. The highest risk was among males who came into contact with the substance under the age of 30.

Cytochalasin inhibits light-dependent synaptic plasticity of horizontal cells in teleost retina.

Previous studies have shown that the horizontal cell-->cone photoreceptor negative feedback synapse in teleost fish retinae is 'plastic', being suppressed in the dark and potentiated by light adaptation. The possible involvement of filamentous actin in ultrastructural and electrophysiological aspects of this plasticity has been investigated using cytochalasins, which inhibit actin turnover, in the cyprinid fish (roach) retinae. Cytochalasin B or D (40 microM) inhibited both the light-dependent formation and maintenance of spinules, and enhancement of the feedback interaction involved in generation of biphasic spectral responses in horizontal cells. The results suggest that actin turnover is essential for both ultrastructural and electrophysiological plasticity of horizontal cell feedback and that spinules could mediate this dynamic interaction.

[Evaluation of antianginal effects of running pulse magnetic field and drug therapy on the physical working capacity and hemodynamics in patients with stable angina pectoris]. / Otsenka antianginal'nogo vliianiia begushchego impul'snogo magnitnogo polia i farmakoterapii na fizicheskuiu rabotosposobnost' i gemodinamiku u bol'nykh so stabil'noi stenokardiei.

The effects of the running pulse magnetic field, antianginal drug therapy and their combinations on the physical capacity were compared in 60 patients with Functional Classes I-III stable angina pectoris. Monotherapy with the running pulse magnetic field was found to produce an antianginal effect in patients with Functional Classes I-II angina pectoris, but the efficacy of drug therapy increased when antianginal drugs were used in combination with running pulse magnetic field in patients with severe angina.

Monosynaptic connections between LPa7-LPa3 and LPa9-LPa3 neurons in the central nervous system of helix pomatia. Electrophysiological characteristics, monosynaptic plasticity, neurotransmission.

Monosynaptic inputs from LPa7 and LPa9 cells onto the LPa3 neuron were investigated in the isolated central neurons system (CNS) of snail Helix by means of simultaneous intracellular recording from pre- and post-synaptic neurons and electrical stimulation of the presynaptic neuron through the recording microelectrode. Each action potential of either presynaptic cell produced excitatory postsynaptic potential (EPSP) in the follower one with an amplitude of 0.6-5 mV. Repetitive suprathreshold stimuli, applied at frequencies higher than 1 per 5 min, induced depression of the monosynaptic response. The cholinergic antagonists, atropine and d-tubocurarine (10(-6)M- 10(-4)M), dose-dependently inhibited monosynaptic EPSP from either presynaptic cell. Cholinergic transmission is suggested between LPa7-LPa3 and LPa9-LPa3 cells.

[Effect of beta-adrenergic blockaders and trental on plasma levels of renin and aldosterone in healthy persons during antiorthostatic hypokinesia]. / Vliianie beta-adrenergicheskikh blokatorov i trentala na soderzhanie renina i aldosterona v plazme krovi zdorovykh lits v usloviiakh antiortostaticheskoi gipokinezii.

Plasma renin activity and aldosterone levels were measured radioimmunologically in 30 normal individuals subjected to antiorthostatic hypokinesia (at a - 15 degrees angle). Hormonal effects of some drugs (beta-blockers, trental, venotonics) were examined. The short-term antiorthostatic position was associated with a disordered hormonal control, reduced plasma aldosterone and enhanced plasma renin activity, as compared to the respective parameters of the reclining position. The use of beta-adreno-blockers alone or in combinations with other drugs decreases plasma renin activity in conditions of antiorthostatic hypokinesia which can be related to the inhibition of beta-adrenergic activity.