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Biomedical subjects

G S Katinas

Publications and source records attributed to G S Katinas.

At least 19 recordsLinked to original sources
PubMed1992

[The dynamics of the reparative regeneration of the rat epidermis exposed to lysylproline].

Under study was the spatial distribution of mitotic activity (MA) of the rat epidermis in the process of reparative regeneration of the skin for a distance of 6 mm aside from the wound margin, as well as the action of lysyl-proline (LP) on the process which is a product of natural decay of collagen. The wound was made by cutting a skin flap (0.5 x 3 cm) from the area of the back. A teflon ring was introduced through the incision in the cranial direction at a distance of 3 cm. Control animals were given 1 ml of the isotonic solution of sodium chloride injected in the hole of the ring, for experimental animals the solution additionally contained 20 mkg of LP. Healing of the wound in control and experimental animals had the features generally corresponding to the regularities established earlier. It was also found that mitotic activity was growing irregularly forming waves. During 11 days of observations these waves sometimes came nearer to the center of the wound, sometimes moved away. The influence of LP manifested itself in the waves of MA reaching the wound center 1 day earlier, and the approximation and divergence of the waves were smoother, MA was higher and epithelialization of the wound surface also came 1 day earlier. Since the contraction of the wound in experimental animals was also more rapid (activization from the 3rd day), a conclusion can be made of the stimulating influence of LP on the course of the reparative regeneration of the epidermis observed as long as 1.5 weeks after a single injection of LP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Changes in the cell population of the thymus-dependent area of the regional lymph nodes following skin flap grafting].

In the paracortical zone of the regional lymph node changes in the cell population density of small and middle lymphocytes, immunoblasts, immature and mature plasma cells are taken into consideration. The observations are carried out for 954 h after transplantation. As demonstrates the analysis of the process segmentation, certain stages of the changes are revealed with duration of 150-160 h; that corresponds to circadian (circaseptan) range of biological rhythms. The duration of the first stage makes about a half of the circaseptan period. In quantitative changes of every cell type a slow trend and a periodical component are present. It is possible to suppose that during the first 3-4 days mobilization of cell resources takes place, further up to 13-16 days active reactions occur, directed to exfoliation of allogenic tissue components, and then after the exfoliation of the graft the amount of the cells becomes stable, however, rhythmical fluctuations are preserved. The reaction of the cell composition in the paracortical zone of the lymph nodes is in concord with the dynamics of changes in the cell population and in the transplant itself.

Animals↗
PubMed1987

[Succinate dehydrogenase activity of brachial muscle antagonists after decrease in the force load at various times of the day in rats].

In 140 male rats of Wistar strain the distal part of one thoracic extremity has been amputated in such a way that places of the brachial muscle fixation remained intact. This resulted in decrease of the force component of muscle contractions (more intensive in the musculus triceps brachii) without essential swing and speed of movements. The operation was performed during one day at three series: at 7 a. m. 3 p. m. and 11 p. m. During following 45 days the muscles developing various contraction force were studied: the medial head of the musculus triceps brachii and brachial muscle. Succinate dehydrogenase (SDG) activity in muscle fibers (MF) was estimated photometrically. In MF initially characterized with various SDG activity, attention was payed to its dynamics and also relation of the fibers number, possessing various level of the enzymatic activity was taken into consideration. SDG activity in MF and relation of various MF change wavy-like, fluctuating from the control meaning and returning to them again. MF with different SDG activity do not similarly react to a sharp decrease of the force loading. Fibers with high enzymatic activity react to changes of the force loading immediately, intensity of the reaction at this stage slightly depends on degree of biomechanical changes; at later stages the response is differentiated: if the loading is decreased considerably (musculus triceps brachii), the process continues developing and increasing uninterruptedly, if it decreases moderately (brachial muscle)--it stabilizes and even has tendency to adaptation and returning towards the control state.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Pathogenesis of experimental thyrotoxic myopathy.

Focal degenerative changes of skeletal muscle fibers (decrease in mean diameter, excessive axonal branching and a decrease in the mean diameter of motor end-plates together with a reduction of their acetylcholinesterase levels) were found by means of the experimental model thyrotoxic myopathy in mice compared to controls. A decrease in protein kinase affinity to cAMP and an increase in the number of nucleotide binding sites were revealed with a simultaneous decrease in cAMP level. The weakening of hormonal control of cAMP-dependent processes is probably the basic cause of muscular weakness and structural changes in skeletal muscles in thyrotoxic myopathy.

Acetylcholinesterase↗
PubMed1985

[Changes in the activity of succinate dehydrogenase in muscle fibers of functionally different muscles in the rat after a reduction in exertion--hypodynamia].

In 105 male rats of Wistar strain distal parts of one of the thoracic extremities are amputated with keeping intact the places where the brachial muscle is fixed. This does not restrict the volume of the brachium movements but essentially decreases their dynamic component (power loading). For 45 days dynamics of succinate-dehydrogenase (SDG) activity is being revealed in muscle fibers (MF) of functionally different muscles: m. brachialis, m. serratus ventralis and m. triceps brachii (the medial head). Average tendency of the process, changes in the distribution margins, asymmetry and kurtosis are taken into account. Under hypodynamia reconstruction of the MF has a wavy character with a gradually longer period of fluctuations. In all the muscles appear MF with a greater than in the control SDG activity. In the medial head of the m. triceps brachii the fibers with the lowest SDG activity disappear. The amount of MF with the lowest activity decreases, while those with the higher--increases, the process being more pronounced in the m. triceps brachii. The amount of MF with middle activity of the enzyme remains nearly unchanged. MF with different initial enzymatic activity do not change simultaneously. The degree of the changes in the fibers and the power leading are connected with each other, the fibers with the low initial SDG activity including into the reaction at a sharper decrease of the latter. The changes in quantitative ratio of MF with different SDG activity are not the same in every muscle studied.

Animals↗
PubMed1985

[Size of cardiomyocytes in different regions of the rat heart].

In rats after alcaline dissociation of the heart at the state of systol and diastol, length and width of cardiomyocytes have been measured, their volume has been calculated. Statistical characteristics of distribution connected with the first four moments have been taken into consideration. Certain size differences of cardiomyocytes in five cardiac parts have been revealed, as well as peculiarites of their variability that is connected with an individual and internal changeability. In the atria predominates the first, in the ventricles--the second. If the internal changeability of the cardiomyocytes in all the cardiac parts is mainly the same, the individual one--is different (in the atrii it is 2 times as great, in the interventricular septum it is the same as in the atrii). The individual changeability of the cardiomyocytes volume is also greater than that of their size. This also proves the variability of their proportions. The degree of their contractility makes 11--20%, differences between the cardiac parts are not significant. The data obtained could be used as normatives for various experiments.

Animals↗
PubMed1984

[Pathogenesis of experimental thyrotoxic myopathy].

The data obtained in mice with experimental thyrotoxic myopathy included a decrease in the median diameter of the muscle fibers by 17.1 per cent and various focal degenerative changes in less than 20 per cent of the muscle fibers; a statistically significant elevation in the activity of alpha-glycerophosphate dehydrogenase, as well as a reduction in phosphorylase activity and glycogen levels. There was also a significant diminution in the median diameter of the motor terminal plates, a decrease in cholinesterase activity and intensified collateral ramification of the distal axons. The major cause of the muscular weakness and structural changes in the skeletal muscles in thyrotoxic myopathy seems to lie in lowered cAMP concentrations and a weakened cAMP-dependent regulation of protein kinase.

Animals↗
PubMed1982

[Role of factors affecting the diameter of capillaries in postmortem examinations].

In 20 mongrel dogs by means of four methods (injection of Indian ink and gelatin, impregnation after Bielschowsky--Gros, injection of 1% colloid silver solution and erythrocytes staining with benzidine) capillaries in the musculus sternomastoideus have been revealed. The capillary diameters are measured with a screw ocular micrometer and treated by means of variational statistics methods, three-factor dispersion analysis including. The role of the factors affecting the capillary diameters in the process of their revealing is defined. The controlled factors determine 81% of total variation, out of them the investigation methods--70%, individual variability of the animals--1.2%, conditions for making preparations--0.1% and 2.9% are connected with the interrelations of the factors mentioned. Each method makes certain distortions in the measurements, but, at the same time, is specific for revealing various structural details. Therefore, in order to study the capillaries, it is necessary to apply their combinations.

Animals↗
PubMed1982

[Effect of thyroxine and methylthiouracil on the development of intramural ganglia in the chick embryo digestive tube].

The development of the vegetative muscular-gastric plexus ganglia has been studied in 17-day-old chick embryos at administration of thyroxin and the inhibitor of its production - methylthiouracil. The substances in question are injected into the air chamber of the egg on the 3d days of incubation. In histological preparations, stained after Nissl, with hematoxylin - eosin and silver impregnated, the total number of cells of the neuroblastic line and that of differentiated neurons are calculated in 50 ganglia. Under thyroxin effect the number of the differentiated neurons in the ganglia increases, while the total number of the neuroblastic cells (comparing to the control) remains constant. Under methylthiouracil effect the number of the differentiated neurons decreases and so does the total number of the neuroblastic cells. Thyroxin and methylthiouracil differently affect the differentiation rate of the neurons at various stages of this process. The effect of the drugs applied is poorly manifested in the duodenum, where (in the control) the total portion of the differentiated cells is higher than in other segments of the digestive tube, and the number of the ganglia without such cells is lower, while the portion of the ganglia with numerous differentiated neurons is more significant.

Animals↗
PubMed1981

[Dynamics of tissue reactions following allotransplantation of a complete thickness skin flap in mice. 1. Epidermis and its derivatives].

A complete skin graft (1.5 x 2.5 cm) from mice C3H was transplanted to mice C57Bl. Destructive changes in epidermis and its cells were accompanied by its infiltration with lymphocytes and polymorphonuclear leucocytes. After these phenomena intensified, signs of epithelial regeneration appeared at the expense of cambial elements in the area of hairy follicles an sebaceous glands. In response to the epithelial regeneration, lymphocytic infiltration increased, that was followed by destruction of a greater part (but not all) cells of the regenerate. Then another, though a weak, wave of regeneration occurred with a corresponding increase in number of viable epithelial cells was noted on the 66th, 164th and 226th h, and increase -- on the 94--104th and 194th h after the operation. That demonstrated certain rhythmicity in the rejection with the period of about 4 days.

Animals↗