[Enamel structure of atypically formed human teeth].

Using light and scanning electron microscopy thin epoxide processed sections of 12 impacted third molars, one molar developed in odontogenic follicular cyst and one tooth-like teratoma were studied. It was established that the 4 impacted teeth and the tooth developed in odontogenic follicular cyst had obvious signs of enamel damage in the form of erosion in the crown fissures. The features of enamel alteration make it possible to interpret the changes as carious process which apparently has endogenous origin. Tooth-like teratoma extracted from ovarian dermoid cyst looked like canine and incisor "hybrid" coronal portion of which is covered with thin enamel layer, marked by obvious signs of multiple erosive lesions of endogenous nature. But unlike alterations in impacted teeth it resembles either fluorosis or enamel hypoplasia.

[Method of producing histological preparations, equivalent to the large-area semithin sections, for multipurpose morphological studies].

The effective methods for producing large-area semithin sections are presently still unavailable. The method is suggested to alternatively solve this problem without the very procedure of histological sectioning. It includes a modified combination of the methods of tissue fixation and embedding in epoxy resin with the known technique of preparing the ground sections. This method of slide preparation for the microscopical study of large area biological objects gives an additional valuable opportunity, since it allows to study heterogeneous complexes consisting of soft and hard (cartilaginous and bone) tissues without their prior decalcination.

[Dental enamel structure and its relation to dentine].

New information on microscopic and ultrastructural architectonics of human dental enamel and its relation to dentin is presented. Enamel consolidation with dentin is mediated by borderline layer of calcificated substance having fibrous structure.

[Structuro-functional units of the salivary and lacrimal glands]. / Strukturno-funktsional'nye edinitsy sliunnoi i sleznoi zhelez.

By means of the multilayer graphic and plastic reconstruction methods using series of semithin sections, spatial tridimensional organization of the epithelial complexes and blood microcirculatory bed in the rat palatal salivary glands and the lacrimal gland of the human newborn have been studied. Since their ducts serve not only for discharging their secrete into the external medium, but also for accumulation (as collectors), the sublobular unit--adenomere should be referred to as a part of elementary level of organization of the epithelial complexes. The adenomere has in its composition a collecting centrally situating duct. However, while studying structure of the blood microcirculatory bed, it is found out that there is not any strict territorial correspondence between its functional units and structural units of the glandular epithelium. Nevertheless, giving a great importance to a tight syntopic connection of the collecting ducts of the adenomeres with the postcapillary venules (that belong to filtrating microvessels), these are sublobular units--adenomeres that are distinguished as structural-functional units in the glands.

[Mechanism of the development of functional hyperemia in the palatal salivary glands of the rat]. / Mekhanizm razvitiia funktsional'noi giperemii v nebnykh sliunnykh zhelezakh krysy.

At various regimens of the secretory activity in the palatile salivary glands, changes occurring in the transversal profiles of the postcapillary venules, but not of the blood capillaries, are most noticeable. Under food stimulation of secretion, the former dilate essentially, that can demonstrate certain functional hyperemia developing in the palatine salivary glands. Some previous experiments concerning interpretation of principles on the microcirculatory bed spatial organization give a good reason to suggest that dilatation of the postcapillary venules is connected with an increased blood perfusion in the canals of the preferrable blood stream. The postcapillary dilatation is possible because blood from the precapillaries gets into the capacitance blood microvessels and its volume at that moment is greater than the capacity of the venous microvessels. A suggestion is made that filtrative function of the palatile salivary glands depends on development of the functional hyperemia. It is possible, that this mechanism is universal, since owing to it, reflectory reactions of the salivary glands directed to the immediate secure of the oral cavity with a necessary amount of liquor become possible.

[Structural features of the excretory ducts of the palatal salivary glands in the rat]. / Osobennosti stroeniia vyvodnykh protokov nebnykh sliunnykh zhelez krysy.

In serial semithin sections, by means of a transmission and scanning electron microscopy, perforating holes, through which fluid is transported from the interstitium into the ductal lumens, have been revealed in the deferent duct walls of the palatal salivary glands. The mechanism of how these holes are formed is closely connected with secretory process of glandulocytes and is directly dependent on its intensity. The transmural holes increase porosity of the deferent duct walls, thus they contribute to better moistening of the mouth cavity with fluid both under normal and experimental conditions. Their role is especially important when there is a functional insufficiency of the large salivary glands. There are holes not only in the palatal deferent ducts, but also in other small salivary glands of the mouth cavity.

[Structure of the longitudinal suture of the bony base of the hard palate during the period of permanent bite formation]. / Stroenie prodol'nogo shva kostnoi osnovy tverdogo neba v period formirovaniia postoiannogo prikusa.

The investigations performed support the literature data that the longitudinal connective tissue suture in the osseous base of the hard palate during formation of the permanent bite possesses all the necessary tissue components in order to realize certain osteogenic functions. Its blood supply is provided at the expense of the microcirculatory bed including arterioles, precapillaries, capillaries and postcapillaries. The main morphological signs, demonstrating active osteogenic processes in the connective tissue suture of the hard palate, are preserved during the whole period when the permanent bite is forming; they remain more or less constant, while the form of the connective tissue suture of the hard palate undergoes certain rearrangements. It is necessary to note that among tissue components of the longitudinal connective tissue suture of the hard palate, besides osteoblasts and osteoclasts, Sharpey's fibres are important constructive elements. In addition to their mechanical function, they are capable to participate in transport of fluid and dissolved substances from the interstitium of the connective tissue suture into the osseous tissue along peculiar tubules in which the Sharpey's fibres are situated.

[Construction of the microcirculatory bed of palatine salivary glands of rats]. / Konstruktsiia krovenosnogo mikrotsirkuliatornogo rusla nebnykh sliunnykh zhelez krysy.

Owing to multilayer graphic reconstruction, it was possible to state that resistance and capacitance microvessels of the palatal salivary glands are localized within the lamina propria of the palatal mucous membrane. The structural principle of blood transport and distribution is performed by a closed arteriolar system in which separate modules are distinct. In an individual module area there are tightly packed 5--6 glandular lobes, 1 or 2 of them are not connected with the gland which is completely within the limits of the module. The network of the canals delivering and distributing blood among the modules has a concentric-radial form. Every precapillary arteriole, passing in interlobular connective tissue layer towards the center--the collecting vein--delivers blood to two halves of the adjoining lobes. At various levels of organization of the vascular microcirculatory bed in the rat palatal salivary gland, canals with a predominant blood flow are revealed and functional appraisal for each is given. The palatal salivary gland lobe is noted to correspond most fully to our idea of the elementary autonomic secretory unit.

[Methods for working with semi-thin epoxide sections in histological practice]. / Metody raboty s polutonkimi époksidnymi srezami v gistologicheskoi praktike.

Since ordinary histological laboratories have no special equipment, semi-thin epoxide embedded sections, to perfectly suitable to realize the resolving capacity of the light optic are not widely used in histological practice. However, even in an ordinary histological laboratory it is possible to master the method of their production. A special device is suggested to fix glass knives in the rotational microtome MPC-2. Simultaneously, a number of suggestions and recommendations are given as to certain specificities for obtaining serial semi-thin sections and the method for their staining. Besides, an original method is offered for producing film preparations by means of mild tissue compression in the process of polymerization in epoxide resin. This method allows not only to study some features in the composition of complex three-dimentional objects, but to obtain a series of semi-thin sections from the film preparation to reveal intimal interconnections between certain structural components.

[Structural organization of the palatal salivary glands of rats according to the results of stereological analysis]. / Strukturnaia organizatsiia nebnykh sliunnykh zhelez krysy po dannym stereologicheskogo analiza.

By means of semi-thin serial sections and by the method of plastic reconstruction, the palatal salivary gland have been structurally analyzed and some objective data have been obtained on spatial organization of identical glandular complexes which make a component part of the lobule and are known as adenomeres. In the adenomere, several interconnected glandular components are distinguished, the terminal sections, acini comprising the most numerous group among them. An individual acinus is integrated in the adenomere not as its autonomic member but as its intrinsic part. The structural-functional unit of small salivary gland, with the palatal gland being their most representative group, are supposed to occupy the highest level in their structural organization.