[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.

[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.

[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.

[Nucleoli of mesothelial cells during regeneration after injuries inflicted at different times of the day]

Quantitative changes in nucleoli of the mesothelial cells of the rabbit parietal peritoneum have been studied under regeneration when trauma is performed at 8--10 or at 20--22 o'clock. The animals are killed every 3 h after the operation, for 5 days. The nucleoli are studied continuously along 12.8 mm from the edge of the defect in film preparations. Under conditions of posttraumatic regeneration in the mesothelium the number of cells containing 2--3 nucleoli increases. It is connected with the process of synthesis activation which has a wave-like character in time and space. Dynamics of changes in the number of the nucleoli depends on the time when the operation is performed. The operation performed in the morning provokes more intensive and rhythmical reaction. It corresponds to the dynamics of mitotic activity which is also subjected to greater effects of the circadian mechanisms after morning performance of the operation.

[Use of the dynamics of central moments of statistical distributions to analyze muscle fiber differentiation]

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.

[Endothelial cell nucleoli during regeneration after injuries inflicted at different times of the day]

Quantitative changes in the state of the nucleolar apparatus of endothelial cells in the rabbit jugular veins were studied at regeneration after trauma produced either at 8-10 a.m. or at 8-10 p.m. The animals were killed every 3 h after the operation during 5 days. The nucleolar apparatus was studied continuously at the distance of 12.8 mm along the edge of the defect in flat film preparations. The data obtained were treated by methods of variational statistics. In endothelium, the number of cells with greater than normal amount of nucleoli increases under the conditions of post-traumatic regeneration. It is connected with activation of synthesis which has a wavy character in time and space. All quantitative estimations presented demonstrate a dependent character of the changes in the number of nucleoli on the time of the operation. The p. m. operation results in intensified endothelial synthetic activity with a shorter time for reaching its maximum.

Temporal organization of the thyroid gland in A/He mice (morphometric investigation)

Biological rhythms of structural elements of the thyroid gland of A/He mice were studied by morphometric methods followed by spectral amplitude and phase analysis on the Minsk-32 computer. The morphological data show that the activity of the organ is maximal at night. The biorhythms have a complex frequency spectrum, including intradian, circadian, and ultradian components.

[Effect of the time of the day when the lesion was produced on the course of mesothelial proliferation]

The course of mitotic activity in the rabbit mesothelium of parietal peritoneum was studied depending upon the daytime when the lesion was produced. In the first series of experiments (I) the operation was performed from 8 to 10 a. m., and in the second series (II) - from 8 to 10 P. M. After the operation the animals were sacrifieced: one animal every 3 h during 5 days. Mitotic activity was investigated along 13 mm from the edge of the wound in flat film preparations. The data obtained were statistically treated applying approximation of the process course by the method of weighed sliding averages. The first mesothelial mitoses appeared: in the first series (I) of experiments - in 24 h, in the second series (II) of experiments - 21 h. Further, proliferation of the mesothelium appeared in different parts of the tissue with various intencity and was of wavy character. Regardless of the time when the lesion was produced, mitotic activity was the greatest in the first zone, 4.8 mm wide its maximum 33 h after the operation. The character of the regenerative process in the mesothelium depends on the circadian phase of the organism at the time of the operation, that influences the time when mitotic activity begins, its quantitative indices, the area of the tissue involving into the reaction, expressiveness of the rhythmicity of the process. During 5 days, in the II series of experiments three waves were noted, and in the I series - five waves were noted and their periods were near the diurnal.

[Age and biorhythms of the histophysiologic indices of the thyroid gland]

Rhythmic changes of several histophysiological parameters of the thyroid gland was studied in 144 A/He mice of three age groups: young immature, mature adults and ageing animals. The multicomponent nature of the rhythmic changes was found for each index; it included the circadian component, as well as infradian oscillations. The leading role of the circadian component in the establishment of the biorhythms of the organ functioning was shown, whereas ontogenetic changes were chiefly associated with the ultradian components' attenuation.

[Relationship between the time of day of trauma infliction and the dynamics of endothelial mitotic activity]

Endothelial mitotic activity of the rabbit jugular veins depending on the daytime of trauma infliction was studied. In the first series of experiments (I), the operations were performed from 8 to 10 a. m., and in the second (II)-- from 8 to 10 P. M. After the operation one animal was killed every 3 hour, for 5 days. Mitotic activity (MK %) was studied continuously 8 mm from the wound edge in flat film preparations. The data obtained were statistically treated using approximation of the process course by the method of weighed sliding averages. Independently of the time of trauma infliction, the first mitoses in the endothelium appear after 21 h. Further, mitotic proliferation has a wavy character of different intensity in different tissue areas. Lack of similarity in the organism circadiam phase at the time of operation, produces distinct differences in the course of the process which are seen in asynchronity of the daytimes when the rise and recession of mitotic activity occur and in different length of these waves. In I series the length of these waves equals to 36, and in II series-- to 48 h. After the evening operation, 24-hour rhythm superimposed on its aliquat 48-hour activity is slearly seen. After the morning operation, daily rhythm is not observed. After the evening operation the process is more intense and has a greater length along the endothelial layer.

[Use of methods of spectral-correlation analysis for studying the temporal and spatial organization of tissues]

Tissues within the organism represent multidimensional systems organized in time and space and having statistical dispersion in each parameter. Changes in its state may have a character of a monotonous trend and be periodical (the matter of chronobiology). The methods for detection of latent periodicities, developed in chronobiology, are applied for estimation of not only temporary but also spacial characteristics of the object. One of such methods is the calculation of the power spectrum of the autocorrelative function. Examples of its application are given.

[Tissue organization of mesothelium under normal conditions and during reparative regeneration]

The investigation of tissue organization of the mesothelium by non-parametric statistic methods has shown that under conditions of reparative regeneration the principle of organization of the mesothelium as a tissue is preserved. Heteromorphism characteristic of the normal mesothelium is increased at all steps of regeneration, and the degree of the layer organization is decreased. The mitotic activity leading to the reparation of defect develops undulatorily, the periodicity of time does not coincide with the periodicity in space.

[Osteoplasty of the lower jaw with composite grafts]

Experimentally on 32 white rats of Wistar line and on 15 outbred dogs the authors studied plastic properties and healing processes of composite transplants, employed for replacement of mandibular defects. It was found that the composite transplant consisting of an allogenic lower jaw, treated according to "os purum" type, and an autobone was more resistant to infection, showed no rejection response and possessed adequate plastic properties. This enable the authors to apply the mentioned combination clinically in 7 patients with mandibular defects from 3.5 to 15 cm. Favourable results were obtained in every patient: the anatomical shape of the jaw and its functioning was restored, a good cosmetic effect was gained.

[Recovery of muscle functions in rats following prolonged movement restraint]

Experiments were carried out to measure time and force parameters of isometric contractions and structural parameters of muscles of hind limbs of rats which were exposed to hypokinesia for 130 days and then were kept under surveillance for 3 months. During recovery certain functions of the contractile system returned to the normal. At the same time M. soleus displayed persistent changes that were indicative of atrophic developments. Unlike M. soleus where delayed contraction (due to an increase in the time of relaxation) was followed by losses in force, fast muscles (M. ext. digit. longus and M. plantaris) showed recovery of force parameters. They also exhibited delayed contraction due to an increase in the time of tension development and half-relaxation. These differences are associated with dissimilar function and structure of muscular fibers. On the whole, the pattern of recovery of the motor functions reflects responses to an increased load of the neuromuscular system of animals which are kept in large cages after prolonged hypokinesia.

[The rhythm of mucus formation in the small intestinal epithelium of rats and mice]

The diurnal rhythm of mucose formation was studied in the epithelium of villi of the small intestine in rats and mice. The total amount of goblet enterocytes on a villus as well as their amount in the basal, medial and apical areas underwent changes during the day. The period of the greatest mucose formation was noted in the night time. The process of secretion of goblet enterocytes was found to be rhythmical and to alternate with predominant accumulation and producing secretion. The mutual shift of similar processes in the phase was noted at different levels of the villi. In the medial third of the villus the corresponding state is observed later than in the basal third and earlier than in the apical one. The agreement of these processes in time permits considering the villus as a system with circadian organization. The rhythmics of mucose formation in rats and mice has certain species peculiarities: in rats there is no difference in the distribution of goblet enterocytes along the length of the villi, but the diurnal rhythm of the changes of their total amount is more pronounced.