[Evaluation of the endothelial monolayer after re-endothelization of the thoracic duct cryodestruction area].

Using the standard cryodestruction model, the peculiarities of reparative regeneration were studied in cat thoracic duct endothelium. Material was collected 12 hours, 1, 2 and 3 days after the injury and was analyzed using scanning electron microscopy. The restoration of the endothelial layer was shown to be completed by day 3 due to cell migration and proliferation at the margin of cryodestruction zone. The degree of tissue regeneration was evaluated using the topological and informational parameters. The results demonstrated the imperfect completion of regeneration process by day 3; the borderline state of the cellular system was detected together with the possibility of the disturbance of endothelial lining reorganization process. Thus, the informational parameters may be used as the complementary criteria for the assessment of the processes, cellular system state and functioning.

[Electron-tomographic analysis of the Golgi complex structure in cultured cells].

Study of the Golgi complex (GC) in cultured NRK cells using improved method of sample preparation for electron tomography (ET) enabled to detect more fine details of GC structure. With the application of quantitative ET, no numerous vesicles were detected around GC, while most of stacks constantly contained intercisternal connections. It was demonstrated that vesicular-tubular clusters, which serve as the exit sites from endoplasmic reticulum, were composed of two domains: varicose tubules with sparse COPII-coated vesicles and a network of smooth tubules. The data obtained argue against the models of transport, which consider the vesicles as the main or necessary membranous carriers. On the contrary, continuous tubular connections seem to play an important role in traffic joining secretory pathway regions.

[How to measure structures, or new stereology: III. Stereology and electron microscopy].

This review describes modern stereological approaches and methods for estimation of subcellular structures dimensions. These estimators could be used for determination of number- and volume-weighted parameters of particle size. Very often they do not require the application of the disector at the first stage of sampling of images. Additionally, the modified version of the rotator for point counting is demonstrated, which significantly accelerates the morphometric procedure.

[Evolutionary approach to the understanding of structural and functional organization of Golgi apparatus].

This article analyzes the literature data related to the discussion of the main models of intracellular protein transport, including vesicular and cistern maturation-progression models. The existence of an important Golgi complex (GC) component--continuous tubular structures--is emphasized and their possible participation in the intracellular transport is discussed. A brief review is presented, describing the peculiarities of intracellular traffic in eukaryotic species belonging to different stages along the evolutionary process. The evidence suggests that in higher eukaryotes, the dynamic membranous GC system was formed on the basis of tubular networks that performs protein sorting and selective protein transport.

[How to measure the structures, or new stereology. II. Methods of stereological estimation of the absolute dimensions of cell structures in light microscopy].

This review describes modern stereological estimators used for the counting of histological structures and their parameters determination at the light microscopic level. All of these estimators, as a rule, require the preliminary application of a disector for the sampling of images. Nucleator and rotator not only allow unbiased determination of structures absolute dimensions, but also help to save the time used for these operations. In the last years, these stereological estimators are being increasingly used in clinical practice and in electron microscopical analysis.

[How to measure the structures, or new stereology. I. Sampling and orientation of samples].

This article presents a brief review of newly developed methods of modern stereology for measurement of biostructures, which allow to avoid problems of uncertainty and technical difficulties peculiar to old stereology. In the first part of the review, a brief historical report on the development of new stereological approaches and their practical application to the selection and orientation of samples, is given. In particular, Cavalieri's principle, random systematic isotropic sampling, fractionator, isector, orientator and principle of vertical sections are described. Some details for practical aspects of measurements have been provided.

[The valvular apparatus and tissue organization of the endothelium of the thoracic duct]. / Klapannyi apparat i tkanevaia organizatsiia éndoteliia grudnogo protoka.

The structure of ostial valves and valves located along the thoracic duct and of its branches ostial valves and right lymphatic duct ostial valves were studied in 30 experimental outbred dogs and 46 cats. Cryodestruction of thoracic duct was performed in 28 outbred cats. 1, 3, 7 and 14 days later perfusive fixation with intercellular borders impregnation was carried out with simultaneous examination of intact regions of intravalvular segments, cisterna chyli and area of thoracic duct trunks connection with valvular surfaces. Tissue organization in ageing was studied using the intervalvular segment of old animals. Specimens were studied by means of scanning electron microscopy and film preparations of endothelium. Valves, located along the thoracic duct length are bicuspid formations, while ostial ones are falciform and cuneiform respectively in 80 and 20%. Endotheliocytes of cuspids are characterized with high content of microfilaments bundles in the cytoplasm and low content of microvesicles. Cells of the valvular free margin cross the cuspid edge and have adaptive changes preventing their desquamation: fusiform shape, long basal processes and bundles of microfilaments in the cytoplasm. Peculiar "pericyte-like" cells alike with myofibroblasts lie deep in the cuspid thickness close to the sinusal venous side. Fascicles of the duct smooth myocytes reach the base of the valve. Besides, in the ostial valve stroma there is elastic membrane, better displayed along the cuspid venous side. Increased polymorphism and changes of the endotheliocytes metric characteristics were demonstrated in the zones of turbulent lymph flow. Analysis of the newly formed endothelium tissue mosaics allows to reveal mechanisms of monolayer repair: spreading and migration of endotheliocytes on the first day, their proliferation within three days, desquamation of newly formed endotheliocytes and spreading of adjacent cells on later stages.