[Experimental study of osseointegration of zirconium and titanium dental implants].

In an experiment performed on pigs, methods of light and scanning electron microscopy were used to study the interaction of zirconium and titanium dental implants with bone 6 months following their insertion. Distinct features of integration of both implant types with bone structures were detected. Sites of direct contact of bone structures with metal were found to undergo constant remodeling according to biochemical and metabolic conditions in each zone of an implant surface. Statistically the degree of interactive properties of zirconium implants significantly exceeded similar parameter for titanium screws. Along the perimeter of the zones of bone contact with zirconium implants greater numbers of forming and formed bone areas were revealed as compared to the zones of bone contact with titanium implants, where erosion lacunae were more numerous. The complex of research methods used in this study have not revealed distinct changes in the structure of osteocytes, located in immediate proximity to the metal surface in comparison with more distant sites in the bone.

[Interrelation of matrix vesicles with spatial distribution of mineral component in fibrous and hyaline cartilages]. / Vzaimosviaz' puzyr'kov matriksa s prostranstvennym raspredeleniem mineral'nogo komponeneta voloknistogo i gialinovogo khriashchei.

Mineral components of the human fibrous and hyaline cartilages were studied by the methods of light, scanning, transmission electron microscopy and cryofractography. The interterritorial matrix of the fibrous cartilage was found to contain not only the local deposits of mineral in matrix vesicles, but also the calcified collagen fibrils and interfibrillar spaces forming the collagen fibers and occupying its major part. In the hyaline cartilage and in the territorial matrix of fibrous cartilage, mineral deposits were located in mineralized conglomerates, the basis of which was formed by matrix vesicles, surrounded by collagen fibrils and interfibrillar space substance. Such conglomerates participate in the formation of calcospherites.

[Morphological characteristics of aneurysmal bone cysts in children]. / Morfologicheskie osobennosti anevrizmal'nykh kostnykh kist u detei.

The morphology of aneurysmal bone cysts (ABC) in 10 children was studied by light and scanning electron microscopy. Angiodysplasia signs and disorder of bone remodeling occur in ABC areas leading to secondary hemodynamic disorders and abnormal bone remodeling with predominance of resorption in dynamics of remodeling.

[Ultrastructural organization of the human lamellar bone tissue mineral component in aged and elderly]. / Ul'trastrukturnaia organizatsiia mineral'nogo komponenta plastinchatoi kostnoi tkani u liudei zrelogo i starcheskogo vozrasta.

The lamellar bone mineral component in mature and senile age was studied using the methods of transmission electron microscopy and cryofractography. This component was shown to be formed by crystals (13-4 x 7-8 x 3-4 nm) of the prismatic shape that formed coplanar units (29-3 x 18-21 x 3-4 nm). The peculiarities of mineral particle distribution inside and between the collagen fibrils, as well as on the completely formed areas of bone surface, were detected. It was established that the length and the width of coplanar crystal aggregates was significantly higher in senile age as compared to similar linear parameters defined in persons of mature age (by 17-20 and 5-9%, respectively).

[Structural organization of compact and cancellous tissue of human rib in aging]. / Strukturnaia organizatsiia kompaktnogo i gubchatogo veshchestva rebra cheloveka pri starenii.

Using the scanning electron microscopy the thickness of external and internal layers of compact bone of the rib as well as the structure of its cancellous bone was investigated in humans aged from 19 to 89 years. The differences of bone remodeling mechanism were found in men and women of the older age groups. In men, the gradual attenuation of osseous structures was taking place. In women, bone loss was found to be rapidly progressing due to the elimination of its structural elements (transformation of compact layer into cancellous bone and disappearance of some part of trabeculae from the latter).

[Morphofunctional characteristics of the endosteum in connection with bone remodeling]. / Morfofunktsional'naia kharakteristika éndosta v sviazi s problemoi remodelirovaniia kosti.

Current information on the endost structure at different stages of bone remodelling is given on the basis of the original data and literature. Possible causes and character of the bone cells activity changes during the cycle of remodelling at the decreased functional stimulation on the bone structures and under pathological conditions are discussed.

[Involvement of the anterior longitudinal ligament of the spine in the morphogenesis of osteophytes in spondylosis deformans]. / Ob uchastii perednei prodol'noi sviazki pozvonochnika v morfogeneze osteofitov pri deformiruiushchem spondileze.

Morphology and relief of the mineralizing front of osteophytes associated with lumbar spondylosis have been studied by means of scanning electron microscopy. During osteophyte formation deep-laid fibers of anterior longitudinal ligament of the spine undergo mineralization followed by their resorption and subsequent replacement by bone structures. Osteophyte surface at its apex consists of mineralized fibers of longitudinal ligament of the spine, formed by mineralized cartilage structures in the area adjacent to the intervertebral disk and by resting bone surface with zone of bone formation and resorption in the area adjacent to longitudinal ligament of the spine.

[Features of the relief of the mineralized surface of the lacunae and canaliculi in lamellar bone]. / Osobennosti rel'efa mineralizovannoi poverkhnosti lakun i kanal'tsev v plastinchatoi kosti.

By means of cryofractography relief of mineralized surface of lacunae and canaliculi of human lamellar bone has been studied. Their walls consist of mineralized collagen fibrils and mineralized ground substance. The intrafibrillar crystals are rod-shaped and are arranged as elongated helicoidal chains. Mineral crystals localized in the interfibrillar spaces are plate-shaped and are arranged in parallel layers. Net of microcanaliculi with diameter of 20-50 nm is found in bone matrix. This increases the surface available for the exchange between mineral and bone extracellular fluid.

[Morpho-functional correlations of the structure of bone cells and adjoining bone matrix in the developing bone]. / Morfofunktsional'nye korreliatsii struktury kostnykh kletok i podlezhashchego matriksa v razvivaiushcheisia kosti.

By means of scanning and transmissive electron microscopy methods structure of the developing bone has been studied. Interconnection of the cell structure and spatial organization of the adjoining matrix has been demonstrated. On the surface of the growing bone not only forming areas have been revealed, where under osteoblasts at various functional states, osteoid layer is determined, but also areas of resorption and completed osteogenesis. This demonstrates an interrupted character of osteogenesis at modelling. At the same time for the remodelling process presence of erosive lacunae is specific; they are filled with a newly deposited collagenous matrix. Therefore, it is possible to suppose that formation of the bone as an organ during the postnatal development includes in itself both mechanisms supporting its form at outgrowth of the osseous matrix volume (modeling) and its continuous rearrangement and adaptation to real conditions of functioning (remodelling).

[Morphological aspects of the mineral phase of the bone]. / Morfologicheskaia kharakteristika mineral'noi fazy kosti.

By means of light, scanning and transmission electron microscopy structure of the mineral phase of human compact bone have been studied. Mechanical properties of deorganified bone samples have been determined. High compressive strength may be in connection with interactions of plate-like mineral particles at the level of hydrate shell of the bone mineral crystallites.

[Characteristics of elastin from the wall of human large arteries during treatment with formaldehyde]. / Kharakteristika élastina stenki krupnykh arterii cheloveka pri obrabotke formal'degidom.

Biochemical studies of elastin from human large arteries wall were carried out using both native and treated with formaldehyde protein. No differences were observed in sensitivity of native and formaldehyde treated elastin to the effect of various proteases and to alkaline-alcohol hydrolysis. Fractions obtained after enzymatic and alkaline hydrolysis were similar in their composition.

[Morphofunctional characteristics of the endosteum]. / Morfofunktsional'naia kharakteristika éndosta.

Basing on the literature data analysis, modern notions concerning endosteum structure, its connections with the bone and bone marrow are presented. Participation of the endosteum in processes of osteogenesis and resorption, as well as its changes with ageing are discussed.

[Spatial organization of the lacunar-canalicular system in the structures of bone lamellae]. / Prostranstvennaia organizatsiia lakunarno-kanal'tsevoi sistemy v strukturakh plastinchatoi kosti.

By means of light microscopical techniques and scanning electron microscopy spatial organization of the lacunar-canalicular system (LCS) has been studied in structures of a mature lamellar bone. A method for making corrosive casts of osseous lacunae and canaliculi is suggested, owing to which their spatial organization can be analysed. Certain data on interconnections of the osseous lacunae with each other and with vascular canals and natural surfaces of the bone are presented. The role of LCS as a component of the microcirculatory bed of the lamellar bone is discussed.

[Structure of the erosive lacunae on the periosteal and endosteal surfaces of bone]. / Struktura érozionnykh lakun na periostal'noi i éndostal'noi poverkhnostiakh kosti.

The periostal and endostal surfaces of the femur, ribs and lumbar vertebrae have been investigated in people at the age of 20-90 years. The erosive lacunae on the surface of the bone are revealed as recesses of various form and size. They are usually encountered as groups forming a resorptive focus, or fuse into large zones of resorption. Comparing the data of the light optic investigation and the results of SAM studies of the bone surface, it is possible to distinguish the erosive lacunae with an active process of resorption from the lacunae, where the process proceeds slowly or is not yet fully completed. On the periostal surface the resorptive foci are revealed more often, while on the endostal surface--large zones of resorption are seen. The erosive lacunae are often situated in the ostial parts of the vascular canals. No age dependence is noted in morphological manifestation of the resorption process on the investigated osseous surfaces of a mature person.

[Topography of the mineralization front on different surfaces of the body of a vertebra]. / Rel'ef fronta mineralizatsii na razlichnykh poverkhnostiakh tela pozvonka.

Peculiarities of the relief of the mineralization front have been investigated on the periostal surface of the human vertebral body in several zones. The material has been obtained from male persons at the age of 20-84 years and studied by means of the light and scanning electron microscopy. The size of lateral surfaces of the vertebral body does not differ essentially from the relief of the periostal surfaces of other bones. In people of middle age certain changes in structure of the mineralized cartilage plate in the area adjoining the nucleus pulposus and the fibrous ring of the intervertebral disc are demonstrated. In persons of elderly and old age a definite decrease in thickness of the cortical layer of the vertebra is noted. At the same time, the plate of the mineralized cartilage adjoining the cortical layer grows thicker and collagene fibers in the spinal column ligaments undergo mineralization. Sometimes, microfractures of the cortical plate of the vertebral body and Schmorl noduli are revealed.