Vol 129, No 3 (2006)

The authors define two groups of levels of cortical bone hierarchic organization. The first three levels (molecular, supra-molecular and tissue) are characterized by age-dependent changes in connections and geometry of collagen fibers, deviations in orientation and interaction between collagen and minerals, increase in crystallinity and size of the latter, resulting in matrix hypermineralization. It causes water and organic fraction displacement, as well as intermolecular space reduction, which provides for lesser amount of matrix deformations under the influence of mechanical forces. At the next three levels (structural-functional, organ-forming structures, organ) adaptation processes contribute to deformation increase due to a greater volume of cavities (Haversian canals and medullar cavity of the diaphysis of long tubular bones). These are due to the fact that osseous tissue cells possess superior and inferior thresholds of deformation perception, and through modeling/remodeling provide for extracellular matrix migration in the direction limited by these thresholds. Bone geometry changes leading to bone mass loss are also caused by age-dependent rise of the inferior threshold of sensitivity to mechanical impulses and decrease of muscle functional activity. Prevention of the described changes may be possible through elaboration of new, pathogenesis-based ways of drug therapy, including 1) osseous tissue mineralization reduction with the help of osteocyte pump regulators for predominant washing out of Ca2+, 2) lowering the threshold of electric impulses initiation arising in the osteocyte network under mechanical deformations.

Nitric oxide synthase (NOS) expression in human intracardiac ganglia was studied using two techniques - histochemical demonstration of NADPH-diaphorase and immunohistochemical staining for NOS1. To detect the influence of coronary heart disease on NOS expression, hearts were studied in patients that died from heart failure (n=8) and in persons that died in accidents (n=3, control). It was found that human intracardiac neurons normally expressed mainly NOS1, and the proportion of these cells amounted to about 40%. A portion of neurons with low and moderate density of staining for NADPH-diaphorase was increased in ischemic myocardium, probably, due NOS2 induction.

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.

The aim of the present study was a comparative assessment of L-, D-and DL-carnitine effect on morphometric and histological parameters of myocardium, skeletal muscles (m. gastrocnemius) and liver in 60 rats fed carnitine-deficient diet. Carnitine-deficient diet fed 2 months resulted in a substantial reduction of carnitine concentration in blood plasma of rats. In carnitine-deficient animals, lipid vacuoles were found to accumulate within the hepatocytes in all the zones of hepatic lobules, which mainly had the character of micro- and macrovesicular steatosis. This was accompanied by a reduction of skeletal muscle fiber and cardiomyocyte average thickness. L-carnitine administration resulted in the compensation of carnitine deficiency in animals with alimentary carnitine deficient state, while the racemate and D-stereoisomere did not affect its content in blood. Pharmacological correction of carnitine deficiency with L-carnitine prevented the development of liver fatty dystrophy to a greater degree, than the administration of other carnitine stereoisomeres and promoted the restoration of muscular fiber thickness of skeletal muscles. DL-carnitine administration was accompanied by a moderate correction of fatty dystrophy and did not prevent the development of skeletal muscles atrophy. D-carnitine stereoisomere did not prevent liver fatty dystrophy, but it reduced its severity. Correction of carnitine deficiency with D- stereoisomere was not accompanied by essential morphological and morphometric differences in degree of skeletal muscle atrophy.

Using the methods of light microscopy, the histological structure of the spleen in Baikal seal (Pusica sibirica Gmel.) pups was studied for the first time. It was found that in Baikal seal the spleen is characterized by highly developed supporting elements (thick capsule and numerous branching trabeculae), which are rich in smooth myocytes. By the age of 2-4 weeks, all the structures of white pulp were formed, however, presence of only a few lymphoid nodules with the absent germinal centers indicates that functionally these structures are still immature. Presence of immature forms of granulocytic, erythroid and megakaryocytic lineage shows that the myelopoiesis in Baikal seal spleen continues in postnatal period.

The aim of the present study was to investigate structural pattern of human placental barrier elements using light and electron microscopy and immunocytochemistry. Some important peculiarities of organization of the placental barrier were detected: difference in structure and amount of collagen IV in the basal lamina of endothelium and trophoblast, occurrence of smooth muscle actin in the capillary wall forming syncytiocapillary membranes. In the intercapillary stroma of terminal villi, both fibroblasts and macrophages but not myofibroblasts were found. Since smooth muscle cells and myofibroblasts are absent, pericytes are most likely cells to contain smooth muscle actin in the area of syncytiocapillary membranes.

The aim of this study was to determine the distribution of cytochrome oxidase activity in the visual cortex of normal kittens. Method of computer filtration of digital images of frontal sections was used. The periodicity of enzyme activity in layers III, IV, VI of area 17 and in layers IV, VI of area 18 has been shown.

Comparative assessment of posthumous and intravital methods of morphometric study of the pelvis in adult persons was performed in 110 embalmed anatomical specimens and in 81 patient. It was proved statistically, that magnetic resonance tomography and spiral computer tomography (SCT), performed following definite algorithm, appear to be highly informative methods for the evaluation of pelvimetric parameters. They permit to define various osseous landmarks with high precision and to perform the measurements of linear metric pelvic parameters. On the basis of the data obtained, various pelvimetric indices that characterize bony pelvis shape, could be reliably calculated. Moreover, SCT together with shade surface reconstruction in different projections permits to demonstrate visually the 3D shape of the pelvis or its separate fragments and to evaluate the symmetry, presence or absence of bone structural deformations.

This paper reviews the literature data on morphological and biochemical aspects of skeletal muscle injury by exercises, hypodynamia and microgravity. Muscle injury depends on the duration and intensity of action. In spite of differences of muscle injury mechanisms by exercises and hypodynamia, this injury restricts muscle function and capacity to continue muscle work. Possible approaches to minimization of the muscular tissue injury and accelerating its regeneration are discussed.