[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.

[Compensatory and adaptive responses of the myocardium to incorporated radionuclides and hypokinesia].

This investigation was aimed at the morpho-functional evaluation of rat myocardium after isolated or combined effect of hypokinesia and 137Cs incorporation. Histological, morphometric, cytophotometric, radiometric and statistical methods were used. The histological characteristics of rat myocardium after exposure to both factors are presented, and the differences in the mechanisms of the compensatory response are shown. The incorporated radionuclides were found to cause early cellular death, which became attenuated with the extension of exposure period. The remaining cardiomyocytes underwent structural changes and hypertrophy, while the total heart mass remained unchanged. The combined action of radionuclides and hypokinesia resulted in the aggravation of the negative effects of both factors causing more profound destructive changes in the myocardium.