[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.

[The sequence of nephron tubule differentiation in the definitive human kidney during the fetal period].

The regularities of the formation of the undifferentiated renal tubules in the definitive kidney were studied in 174 human embryos and fetuses at 4.5 to 40 gestational weeks. On the basis of the study of morphological and morphometrical parameters of these tubules, it was shown that the increase of the average tubular crossectional area was associated with the consecutive formation of the nephrons of the definitive kidney and the differentiation of the segments of their tubular portions. The increase of the proportion of the epithelium in the structure of undifferentiated tubule is determined by the segregation of the proximal and distal tubules within the forming nephrons. The sequence of the initial stages of the renal tubule differentiation is dictated by the ergontic correlations; it developes from the proximal tubule to the distal one and is different from the succession of their formation in the process of the early nephronogenesis.

Embryonic morphogenesis of the human pituitary.

Light microscopy methods were used to study the main stages in the organogenesis of the pituitary in human embryos at Carnegie stages (CS) 12-23. Rathke's pouch (RP) was shown to form as a traction fold over whole width of the roof of the stomodeum in embryos at CS 12 due to a flexure of the neural tube with which the epithelium had a tight anatomical relationship (the attached part of the anterior wall of the RP) in the median plane of the embryo. The rudiment of the hypothalamic infundibulum and neurohypophysis formed at CS 15, as a thickening of the posterior wall of the diencephalon. Transorientation of the positions of brain components, including the rudiment of the hypophysis, occurred at CS 20-23. The attached part of the anterior wall of the RP then formed the pars intermedia and pars tuberalis of the anterior lobe, while the epithelium of the orifice of the RP and its posterior wall formed the pars distalis. From CS 20 to 23, the RP epithelium formed the structural-functional units of the adenohypophysis, i.e., the epithelial cords, by invagination.

[Human pituitary embryonic morphogenesis].

Basic stages of pituitary gland organogenesis were studied using the methods of light microscopy in human embryos at Carnegie stages (CS) 12-23 (25-57 postovulatory days). It is shown that Rathke's pouch (RP) is formed like a traction fold along the whole width of the stomodeum roof in embryos at CS 12 as a result of a neural tube bend, to which the epithelium is closely connected anatomically (attached part of RP front wall) in the middle plane of the embryo. At CS 15 the primordia of hypothalamic infundibulum and of neurohypophysis are formed as a thickening of diencephalic posterior wall. At CS 20-23 transorientation of brain components, including hypophyseal primordium, takes place. After that the attached part of RP front wall forms pars intermedia and pars tuberalis of the pituitary, and the epithelium of RP orifice and that of its posterior wall forms pars distalis. During CS 20-23, structural-functional units of adenohypophysis--epithelial cords--are formed due to invagination of RP epithelium.

[Role of provisionality principle in realization of phylembryogeneses].

The analysis of histogenesis of skeletogenic tissues and of organogenesis of the mesonephros and metanephros in higher mammalian animals and man, is presented. The new conception of provisionality is formulated, according to which embryonic primordium and/or its derivatives possess a determined capacity to form, on its course to definitive state, temporary structures (tissues or organs), which fulfil the vital functions in the developing organism and modeling the mechanisms of development and formation of structural and functional units or the whole organ at the level of definitive morphological substrate. Provisionality is regarded as the universal principle in realization of of phylembryogeneses.

[Hemodynamic disorders in patients with ischemic heart disease after aortocoronary bypass during transportation from the operating room to intensive care units and their prevention]. / Gemodinamicheskie narusheniia, voznikaiushchie u bol'nykh s ishemicheskoi bolezn'iu serdtsa posle aortokoronarnogo shuntirovaniia pri transportirovke iz operatsionnoi v otdelenie intensivnoi terapii, i ikh profilaktika.

Changes in homeostasis of 33 coronary patients after aortocoronary shunting, developing in the course of transportation of the patients to reanimation department, were studied. The causes of some shifts in the homeostasis were revealed. Methods for the prevention and therapy of these disorders were developed.

[Implantation growth of nephrogenic tissue and the epithelium of renal nephron tubules in cultures within the body]. / Implantatsionnyi rost nefrogennoi tkani i épiteliia kanal'tsev nefrona pochki v kul'turakh v organizme.

Comparative study of the implantation growth of nephrogenic tissue in a 17-day-old embryo of rats and the epithelium of nephrons in the one-month-old animals showed that nephrogenic tissue in the implants manifested regularities characteristic of its histogenesis. The nephron epithelium of the one-month-old animals is characterized by tissue growth and formation of atypical organ structures, this indicating its capacity for tissue and organotypical differentiation. A conclusion was drawn on wide range of the reactive and plastic properties of a nephron epithelium, as well as on the existence of its organotypical differentiation.