Biomedical subjects
Publications and source records attributed to I P Rekhacheva.
Major trends in improving histology, cytology, and embryology training of students of a dentistry faculty are presented. Approaches to selecting the topics and improving the training and control of acquired skills and knowledge are discussed. A most important feature of training is its integration in further medical education.
The problem on presence of muscle fibers (MF) types is an actual one, since it is a prerequisite to forecasting certain changes in MF under different conditions. The aim of the investigation has been to find out whether independent groups of MF exist or whether they react as a whole population to gradual changes in pH of the preincubational medium, when dynamic changes in m-ATPhase activity are studied. In serial transversal cryostate slices 10 mcm thick m-ATPhase activity has been defined in MF at preincubation of the slices in media having various pH. The experiment has had three series. In the I--the ventral denticulate muscle with universal biomechanical properties has been investigated; preincubation has been carried out in media having pH from 3.0 up to 11.0 with the intervals 0.5 pH. In the II--besides the muscle mentioned the fast brachial muscle and the force triceps muscle have been studied; preincubation has been performed only at pH 9.5, since in the I series two dissociated groups of MF have been distinguished. In the III series, at studying the same three muscles m-ATPhase activity has been detailed with their preincubation at pH from 3.8 up to 4.5 with the interval 0.1. The m-ATPase activity begins to manifest in various MF at pH of the preincubational medium within the limits of 3.8-4.2. A gradual increase in amount of MF that are revealing, as pH is gradually increasing, evidences most likely against independence of separate groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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)
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.
The antigravitational m. triceps brachii, its antagonist m. brachialis and the muscle having a universal functional specialization--m. serratus ventralis--have been studied in 35 male rats of Wistar strain, 60-105-day-old. Succinate dehydrogenase activity is determined in muscle fibers. Changes in the muscle fibers continue after the rats reach their sex maturation. Certain stageness of the process is observed, but the division of the period into separate steps either is absent (m. brachials), or their number is not great as compared to those during the 1st--60th days after birth. The borders of the periods in the muscles studied coinside (the 70th--74th day). Although it is possible to reveal the periods and separate steps in the changes occurring in the muscle fibers and in the muscles of the animals having reached their sex maturation, nevertheless, the borders between them are not distinct, the reconstruction during this age proceeds slower and more smoothely than before the sex maturation. It is possible that in young rats after sex maturation differentiation of the muscle fibers continues and that, in its turn, stimulates further specialization of the muscles as organs. The changes in the muscle fibers revealed histochemically occur most slowly under a low static loading, and when loading of various modality (kinetic and static) are combined, they are mostly pronounced.
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The aim of the work is to demonstrate how it is possible to get informations of differentiation in muscle fibres by means of evaluating the dynamics of statistical distribution moments. Combinations of various directions of time changes of the standard deviations, asymmetry and excess give the possibility to construct tables in order to get immediate informations on changes occurring in different parts of the distribution (and, hence, on the course of the muscle fibres development) during the whole time of observation (age dynamics of NAD-H-D activity in fibres of musculus serratus ventralis in Wistar rats is studied as an example). Analysing dynamics, as well as real distribution features of the muscle fibres, we got doubtful on the presence of muscle fibre types that could be considered as independent (though possibly as over-lapping) populations. Various differentiation rates of the muscle fibres with different optic density do not mean development of a certain population, but rather reflect an increasing process of development of a part of a single muscle fibres complex, where separate members have various properties and in the course of development they smoothly change them in such a way that uninterruption and continuation of possible intermediate conditions is kept along the whole variational curve. This method could be applied to analyse any other objects after any quantitative sign.
In the denticulate ventral muscle of Wistar rats at the age of 1 day--2 months activity of NAD-N-dehydrogenase, succynic dehydrogenase and cytochrome oxidase has been determined in transversal cryostat sections. Quantitative estimation of the enzymes activity has been carried on by the plag-method. With age, general tendency to increasing activity of the enzymes mentioned is noted, but the dynamics of the increase is peculiar for every enzyme. Analysing the histograms on muscular fibre distribution according to their optical density, it is possible to estimate the dynamics. Simultaneously, the width of variational series, central statistical moments, indices of asymmetry and excess are also estimated. The whole course of the muscular fibre development, in accordance to the range and moments of distribution, can be devided into four main stages: stable, initial stage, slow increase of events, rapid increase of events and stabilization of the process. The stages mentioned pass gradually one into another making it possible to mark transitional stages (5--11, 15--19, 34--60 days). Using standard indices, it is possible to characterize more strictly the processes occurring in the course of muscular fibre differentiation. Lack of parallelism in the dynamics of asimilarity and excess can be treated as variety in differentiation of muscular fibres with middle and large optic density, and parallelism in dynamics--as their simultaneous differentiation. By comparing the curves it can be concluded that up to the 12--14th days, variety in differentiation of muscular fibres occurs, while after the 14th day their differentiation is more regular and simultaneous. The method of cytophotometry with subsequent mathematical processing of the results helps to determine the stages of muscular fibres differentiation.