[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.

Heterogeneity of smooth muscle cells in embryonic human aorta.

Cellular composition of aortas from 5- to 12-week and 18- to 28-week-old human embryos were investigated using immunocytochemistry, scanning and transmission electron microscopy. The aorta of the 5- to 12-week-old embryos consisted of three sublayers differing in cellular composition. The inner sublayer adjacent to the endothelium contained round and ovoid cells with synthetic phenotype. In the intermediate sublayer, spindle-like cells ultrastructurally similar to smooth muscle cells were found. Cells of the outer sublayer resembled fibroblasts or poorly differentiated mesenchymal cells. There were not definite morphological borders between sublayers. In the 18- to 28-week-old embryo aorta the intima was separated from media by internal elastic lamina. Intimal and innermost medial cells had predominately stellate shape and synthetic phenotype. The outer part of media contained spindle-like cells that had well developed contractile structures. Both the 5- to 12-week-old and the 18- to 28-week-old embryo aortic cells were positively stained for alpha-actin and myosin and negatively stained for macrophage antigens. Thus, the majority of embryo aortic cells appeared smooth muscle cells, however there was a regional difference in shape and synthetic state of these cells.

[The hemodynamic effect on the spatial organization of atherosclerotic lesions in the human aorta. Topical differences in the fatty streaks and in the lipofibrous and fibrous plaques]. / Vliianie gemodinamiki na prostranstvennuiu organizatsiiu ateroskleroticheskikh porazhenii aorty cheloveka. Topicheskie otlichiia v lipidnykh polosakh, lipofibroznykh i fibroznykh bliashkakh.

By means of light microscopy of whole-mounted membranous preparations and scanning electron microscopy differences of the three-dimensional organization in the fatty streaks, lipo-fibrous and fibrous plaques in proximal, distal and central parts were investigated. It was revealed that the central parts of the atherosclerotic lesions have a more mature character than the proximal and, especially, distal parts of the plaques. This phenomenon is accounted for by a progressive growth of the plaques along blood flow in distal direction due to the changes in hemodynamics.

[The hemodynamic effect on the spatial organization of atherosclerotic lesions in the human aorta. Plaques at the sites of arterial branching]. / Vliianie gemodinamiki na prostranstvennuiu organizatsiiu ateroskleroticheskikh porazhenii aorty chelovka. Bliashki v mestakh vetvleniia arterii.

By means of light microscopy of whole-mounted membranous preparations and scanning electron microscopy differences of the three-dimensional organization in the macroscopically intact and atherosclerotic human aortic intima in the sites of intercostal artery ostium were investigated. It was shown that the process of atherogenesis begins in the lateral areas and later involves the site of the entry. The flow divider does not contain lipids and resembles fibrous cap of the plaque. Such differences in the three-dimensional organization are accounted for by the local hemodynamic properties.

[Assessment of surface structure of blood cells by phase-contrast and scanning electron microscopy in children]. / Otsenka poverkhnosti arkhitektoniki kletok krovi metodam fazogo-kontrastnoi i skaniruiushchei élektronnoi mikroskopii u detei.

Study of red cell surface structure is a highly informative method for the assessment of the body status in health and disease. The authors have examined the surface red cell structure of infants in health and disease by phase-contrast and scanning electron microscopy and came to the conclusion on the high reliability of the data obtained by phase-contrast microscopy. They recommend this unsophisticated and informative method for clinical practice.

[A comparative ultrastructural and morphometric analysis of the smooth myocytes in the tunicae intima and media of the human fetal aorta]. / Sravnitel'nyi ul'trastrukturnyi i morfometricheskii analiz gladkikh miotsitov vnutrennei i srednei obolochek aorty ploda cheloveka.

Transmission electron microscopy was used for studying the thoracic part of the aorta of 9 human fetuses of 20-28 weeks of development. In the medial tunic of the human fetus aorta there are smooth myocytes (SM) of the contractile and synthetic phenotypes. The latter are localized mainly in the inner part of the media. In the inner tunic there are also SM of the synthetic phenotype. With the help of processes they make contacts with endotheliocytes and processes of SM of the media. In the gaps between the subendothelial SM and endothelium there are particles of elastin which form the structure resembling an additional elastic membrane. It is reasonable to think that the migration of SM into the intima is a stage of normal development of the vessel associated with the adaptation to local hemodynamic conditions rather than an initial manifestation of atherosclerosis.

[Cellular orientation and form in the elastic-hyperplastic layer of the human aortic intima in the area of the ostia of the intercostal arteries]. / Orientatsiia i forma kletok élastiko-giperplasticheskogo sloia intimy aorty cheloveka v oblasti ust'ev mezhrebernykh arterii.

Using the Hatcher monolayer method, it has been shown that the aortic intimal smooth muscle cells, disposed on the flow divider of an intercostal artery, have predominantly spindle-like shapes to be oriented perpendicularly to the long axis of the vessel. Unlike, in the proximal and lateral sites of the intercostal ostium the intima is represented by stellate cells lacking any orientation. These distinctions may be presumably determined by the irregular distribution of hemodynamic loading on the aortic intima in different regions around the ostium of an intercostal artery.

Lipid accumulation in the subendothelial cells of human aortic intima impairs cell-to-cell contacts: A comparative study in situ and in vitro.

We have modified our technique used to examine the three-dimensional cytoarchitecture of human aorta. Using this modification we confirmed the disruption of the contacts among subendothelial cells in the fatty streaks. Thinning and arborization of contact-forming cellular processes were also demonstrated. The incubation of cultured human aortic subendothelial cells with desialylated low-density lipoproteins (LDL), LDL immobilized on latex, and LDL-free latex microspheres induced the alterations in cell-to-cell contacts similar to those occurring in a fatty streak in situ. It is proposed that these alterations may be associated with lipid accumulation and activation of phagocytosis and/or intracellular accumulation of large insoluble particles.

[The three-dimensional structure of the tunica intima and tunica media of the human fetal aorta studied by a new method]. / Issledovanie trekhmernoi organizatsii vnutrennei i srednei obolochek aorty ploda cheloveka s pomoshch'iu novogo metoda.

A new method is developed for revealing the latent surfaces in the structure of organs by scanning electronic microscopy. The method is based on the treatment of specimens with potassium ethoxide until cells start to appear in the dissociating solution. Using this method, thoracic aorta of nine human fetuses at the stage of 20-28 weeks was studied. Subendothelial intima and media of human fetal aorta contain smooth muscle cells differing by their arrangement, shape and surface microrelief. The intima cells are arranged in a mosaic pattern formed of single cells or cell clusters. By means of cell processes they are connected with each other, as well as with endothelial and smooth muscle cells of the media. Smooth muscle cells in the inner part of the media also have processes and form an open network. Part of the cells penetrate the intima through pores of the inner elastic membrane. In the deeper layers of the media, laterally adjoining spindle-shaped smooth muscle cells are found. It is suggested that the observed cell polymorphism is due mostly to penetration of the media smooth muscle cells into subendothelium and modification of their shape under the effect of the microenvironment.

[A method for studying the three-dimensional structure of organs and tissue in pathology]. / Metod issledovaniia trekhmernoi struktury organov i tkanei v patologii.

A new technique of scanning electron microscopy for visualization of hidden cellular surfaces in organs and tissue has been developed. It employs the sample incubation in 30% potassium hydroxide and 96% alcohol mixed in equal amounts and dissociation until single cells appear in the solution, this being checked under phase-contrast microscope. The method is beneficial in non-standard cases of three-dimensional organization of organs and tissues.

[A modified method of endothelium impregnation suitable for pathology studies]. / Modifitsirovannyi metod impregnatsii éndoteliia, udobnyi dlia patologoanatomicheskikh issledovanii.

Prolonged fixation worsens the quality of the endothelium boundaries silver impregnation. A modified method is suggested: the vessel segment is fixed in 2.5% glutaraldehyde for 5 min with subsequent conservation in the saline till the impregnation. Incubation in the saline for 24 hours preserves the susceptibility of endothelium to silver impregnation.

[Changes in the form and ultrastructure of the smooth-muscle cells in the human aorta in prenatal ontogeny]. / Izmenenie formy i ul'trastruktury gladkomyshechnykh kletok aorty cheloveka v prenatal'nom periode.

The shape of smooth muscle cells (SMC) was analysed using the phase contrast microscopy of cell suspensions obtained by alcohol-alkali dissociation, as well as the semithin sections prepared in perpendicular planes. The phenotype of SMC was analysed using transmission electron microscopy. The shape of SMC changes from preferentially round to preferentially spindle-like and stellate one during development. The differentiation of SMC is accompanied with the increase in the contractile apparatus content and in the decrease in the content of synthetic organelles.

[Alcohol-alkaline dissociation of the everted vessel--a simple method for the analysis of the 3-dimensional organization of the arterial intima]. / Spirtovo-shchelochnaia dissotsiatsiia vyvernutogo sosuda--prostoi metod analiza trekhmernoi organizatsii intimy arterii.

A new method to investigate different parts of arterial intima in scanning electron microscopy has been elaborated. A fixated vessel was everted and incubated in dissociated solution of potassium etoxide. Dissociation was performed until the appearance of the first endothelial cells for the analysis of the subendothelial layer, until the appearance of the first subendothelial cells for the analysis of smooth muscle cells, and until the disappearance of any cells for the analysis of the internal elastic lamina. A three-dimensional organization of human fetal and adult aortas, as well as of bovine, swine, rabbit and rat aortas was investigated.