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We present our own experience of assessment of effect of cell therapy on functional state of the myocardium in patients with lowered contractile capacity of the left ventricular myocardium. Intracoronary administration of stem cells in acute myocardial infarction is a safe method of treatment. It does not cause additional damage of the myocardium and does not provoke appearance of malignant arrhythmia. Cell therapy does not affect global left ventricular function. Data we have obtained demonstrate tendency to improvement of myocardial contractile function in dynamics in the majority of studied patients, including patients of the comparison group. This most probably indicates that the given process has been caused by restoration of blood flow to surviving cardiomyocytes after transluminal coronary angioplasty and improvement of function. Confirmation of participation of administered cells in myocardial contraction and improvement of perfusion requires further clinical investigations.

According to A.A. Ukhtomsky, chronotope is defined as a complex of time and space relations between subjects and events that surround human organism. Perception of chronotope by an individual is measured by individual minutes (IM), each minute being measuring in mind, and individual decimeters (ID) depicted by an individual as a line. In case of their simultaneous measuring, IM and ID chronotope is registered. Perception of chronotope has been studied in 31 women and 7 men with chronic cerebral vascular insufficiency and compared to the data obtained earlier in the group of young healthy people used as controls. In patients, giving short measure of time that was not treatment-depended, mismatch of spatial and temporal indices of chronotope measuring and influence of gender were observed.

Aim: To characterize cytarabine effects on human endothelium expression of cell adhesion molecules (CAM) of various classes and interaction of cultured endothelial cells (EC) with blood leukocytes., Material and Methods: Primary cultures of EC of human umbilical vein were obtained by EC culturing for 24-72 h with cytarabine (10 mcg/ml). They were investigated with phase-contrast microscopy, immunohistochemistry and flow cytometry., Results: Cytarabine effects manifested with EC-induced expression of cell surface P- and E-selectines and VCAM-1; ICAM-1 expression rapidly enhanced, leukocyte adhesion to endothelium also activates., Conclusion: Cytarabine, as a pathogenetic factor, induces proinflammatory alterations of the endothelium responsible for development of vascular complications in patients on cytostatic therapy.

Aim: Cytostatic drugs used in the treatment of hemopoietic malignancies affect cells of other organs and systems, vascular endothelium, in particular. This leads to cardiovascular complications. We studied effects of some drugs and their combinations on cultured human endothelial cells (EC)., Material and Methods: Primary culture of umbilical human vein EC was used in the study. Cytosinearabinoside (cytozar, alexan, cytarabin) and daunorubicin were added in concentration from 1 ng/ml to 1 mg/ml; the action of the drugs was assessed by morphology of the cells, their viability, inclusion of bromodesoxyuridine by means of cloning, immunohistochemistry and flow cytofluorimetry., Results: It is shown that in a wide range of concentrations cytosinearabinoside and daunorubicine cause specific structural-functional changes in the cells related to cytostatic and cytotoxic effects., Conclusion: The data of the study confirm that cardiovascular complications in the course of acute leukemia treatment are resultant from systemic damage to vascular endothelium.

Biological effects of ozone on the lipid peroxidation (LPO)--antioxidation system was studied in blood serum of patients with various forms of chronic bronchitis. Breathing ozone was shown to intensify LPO processes and lead to a more considerable deviation of the parameters of non-enzymatic but not enzymatic antioxidants in patients.

In workers afflicted with chronic bronchitis (ChB) after breathing ozone leukocytosis gives place to leukopenia against development of lympho-, monocyto- and neutropenia. In contrast to the workers, in citizens who have not previously contacted ozone chronic obstructive bronchitis is characterized by leukocytosis with less expressed lympho- and neutropenia. Changes in peripheral blood in ChB patients (development of leuko-, lympho-, monocyto- and neutropenia) grow drastically in 5-8 years of ozone inhalation.

Effects of long-term simulation of hypogravity on actin cytoskeleton and cell migration were investigated in cultured human endothelium cells (EC). In control, F-actin resided predominantly on the periphery of cell forming an array of parallel bundles with "dense bodies" along the edge. A small number of actin cable fibers was found in the center. Already after 1-2 hrs of clinostatting at 5 RPM the cell cytoskeleton showed actin filament thinning and displacement toward the cell edges. In subsequent 6-18 hrs, almost all actin fibers had left the center part of EC and had ranged themselves in a continuous F-actin line in the intercellular contact area. In most cases, these changes resulted in the so-called "ruff-edge". Since both the disappearance of cable fibers and formation of the "ruff-edge" add to the cell migration activity, this parameter was studied with the would-healing model. According to our data, 24-48 hrs of exposure to hypogravity stimulates cell migration and expedites 2-3 times reparation of mechanically damaged monolayer. The results suggest that effects of hypogravity on cultured human EC are likely to be consequent to alterations in the activity of protein kinase C and/or adenylate cyclase involving many members of the cellular metabolism.

Effects of hyperthermia (+42.5 degrees C) on the endothelial monolayer organization, actin cytoskeleton and cell viability have been examined in culture of human aortic endothelial cells (EC). Short-lasting hyperthermia (1-4 hrs) provoked disappearance of stress fibers, redistribution of actin filaments to the area of cell-to-cell contacts, shape changes and reorganization of the monolayer. It also stimulated formation of intercellular contacts in a preconfluent EC culture. The cAMP content was elevated one hour after heat treatment and then lowered to negligible values (comparing to the basal cAMP level). Long-lasting hyperthermia (6-72 hrs) resulted in EC injury, and damage of endothelial monolayer accompanied by increased Chromium-51 release and almost complete blockade of [3H]-thymidine incorporation into DNA. Addition of cAMP elevating drugs (forskolin, 8-Br-cAMP or isobutylmethylxanthine) into the cell culture medium prevented heat-induced decrease in cAMP concentration, stimulated EC spreading, protected EC from injury, and promoted integrity of endothelial monolayers. Obtained results indicate that long-lasting hyperthermia can be regarded as an additional factor of endothelium injury involved in development of vascular pathology.

Consideration is given to the place occupied by diseases of respiratory organs in the general structure of morbidity. In many ways, growth in their number has been determined by amplification of anthropogenic factors. This is manifested in emergence of new eco-dependent diseases and syndromes including more difficult course of pulmonary pathology. One of the prioritized disciplines of the modern pulmonology is ecological pulmonology which lies in the domain of medical ecology and is central to the concept of eco-dependent human diseases. A factorial structure of ecological pulmonology built on the etiological principle is proposed to facilitate inquiry into the origin and course of various forms of eco-dependent pathology of the lung.

Experiments on the effects of hypogravity (clinostatting) on growth and formation of monolayer of cultivated endothelium cells of the human umbilical vein demonstrated sensitivity of endothelium to the gravitational stimulus as it responded by a significant reduction of the proliferative activity of cells in culture. The most favorable conditions for cultivating endothelium cells under extended (15-d) hypogravity in vitro were determined.

The authors studied the spatial and temporary organization of the proliferative system and energy exchange in the small intestinal epithelium, as well as spatial and temporary changes in the sensitivity of these systems in mice to typhoid fever infection (cultured Salmonella typhi, 4446) at day and night. The small intestinal epithelial systems were found to show a spatial and time organization and a close correlation between their temporary and spatial changes after infection. The temporary organization of the proliferative system in the esophageal epithelium is more sensitive to infection in the day-time and that of the small intestinal epithelial proliferative system is more marked at night. Thus, these changes are tissue-specific. Typhoid fever infection causes a negative effect on the proliferative system of the small intestine at night and on its energy exchange in the day-time, which shows the system-specific response of the temporary organization of a biological process within the same organ. The changes in the spatial proliferative and energy exchange parameters in the small intestinal epithelium, which have been caused by the infection of animals, depend on the time of a day.

Reported are results of multiyear observation of the structure of individual and population health in Vladikavkaz, and the authors' concept of health recovery and protection through application of modern high technologies of active chronoadaptation to extreme living conditions. The proposed methods of active chronoadapation, i.e. phytocorrection and phytopro-phylaxis, reflexocorrection, bioradiological correction, bioresonance chronolasercorrection can be also of interest for aerospace medicine.

Based on the data available in the literature and his own findings, the author presents a concept of the spatial-temporary organization of biological systems. Experimental evidence is provided for this concept with emphasis on its theoretical and medical values. A role of spatial and temporary organization in the activity of the biological system is shown separately. It is emphasized that the spatial-temporary organization of biological system is not the sum of properties of components of its spatial and temporary organizations and has its own features. The author proposed to single out a section of theoretical biology dealing with the study of the spatial-temporary organization of biological systems and to call it chronotopobiology.

Aim: To study effects of alpha-toxin (AT) Staphylococcus aureus on human platelets and endothelial cells., Materials and Methods: Concentrations of intracellular calcium in human platelets and endothelial cells were estimated by fluorescence, phosphoinositide metabolism in the endothelial cells was studied using 3H-myoinositole., Results: AT induced a dose-dependent increase of intracellular calcium in blood and vascular cells, stimulates dose-dependent formation of inositol phosphates in endothelial cells., Conclusion: AT action on the platelets and endothelial cells results in a significant receptor-independent rise in concentration of intracellular calcium, activation of phosphoinositide metabolism, death of cells. These data support the hypothesis that the platelet and endothelial cell damage is mostly due to the passive Ca2+ influxvia pores formed by AT in cellular membrane.

Using co-culture technique and 3H-thymidine radioautography we have studied effects of human aortic endothelial cells (EC), isolated separately from zones of low (LP) and high (HP) probability of atherosclerosis of grossly normal and atherosclerotic aortas, on 3H-thymidine incorporation by human intimal smooth muscle cells (SMCs). It was found that EC activity depended on a zone of probability, from which the cells were isolated, and on the degree of atherosclerotic lesion. The first-passage ECs from grossly normal LP zones inhibited 3H-thymidine incorporation, compared to control, incubated without Ecs, SMCs (63.5 +/- 27.5%). Cells from HP zones of the same vessels were less active or stimulated SMC proliferation (99.4 +/- 42.9%). EC cultures obtained from both LP and HP zones of atherosclerotic vessels had, as a rule, no effect or increased 3H-thymidine incorporation by SMCs (100.3 +/- 19.8 and 124.1 +/- 20.1%). In contrast to morphologically heterogeneous primary and first-passage cultures obtained from high seeding density, EC monolayers obtained with a split 1:10 were composed predominantly of small mononuclear cells. These cultures effectively inhibited SMC DNA synthesis independently of a zone of probability and a degree of atherosclerotic lesion of aorta (60.4 +/- 10.0 and 51.5 +/- 12.7%). The obtained data suggest that EC morphological heterogeneity is accompanied by functional changes of cells and may be involved in atherosclerotic plaque formation.

In human aortic endothelial cell (HAEC) cultures, obtained separately from aortic zones of low (LP) and high (HP) probability of atherosclerosis, proliferative characteristics of cells and HAEC ability to form colonies at clonal seeding density were studied. It has been found that the population doubling time is significantly higher in endothelial cell (EC) cultures from HP-zones, compared to that in cultures from LP-zones of the same vessels. In cultures from both LP- and HP-zones only a few percent of EC had a proliferative potential enough to form cell colonies. The number of formed colonies was always lower in EC cultures from HP-zones, and decreased depending on atherosclerotic lesions and cell donor age. The obtained data suggest that the decline of EC proliferative potential, mostly in HP-zones (even without visible signs of atherosclerotic lesions) is due to a decrease in the number of cells with a high mitotic activity, i.e. "cambial" cells.

Using immunofluorescence and flow cytometry, we studied the surface expression of cell adhesion molecules, E-selectin, VCAM-1 and ICAM-1, in human umbilical vein endothelial cells (HUVEC) co-cultured with human aortic intimal smooth muscle cells (SMC). It was found that inactivated HUVEC constitutively expressed only ICAM-1. After 3-4 h of co-culturing with SMC in the Transwell system we observed the appearance of E-selectin and VCAM-1, and the increase of ICAM-1 content on the cell surface. In all the cases, the maximum expression of these molecules (85-100% of positively stained cells) was detected within 18-24 h after co-culturing. Similar effect was exerted by SMC-conditioned culture medium, whose action well compared with that of a direct addition of interleukin-1 to EC at a concentration of 5-10 u/ml. The obtained data suggest that the cytokines secreted by SMC may participate in the regulation of endothelial cell adhesion molecule expression, and influence cell accumulation in sites of inflammation, immune disorders, etc.

The rhythmical character of the function of the proliferative system of the oesophagus epithelium of mice changed after infection by Salmonella typhi and after injection of lomefloxacin to intact and infected mice. The degree of the changes depended on the exposure time. The proliferative system of the oesophagus epithelium was more resistant to the infection in the night-time than the day-time and equally resistant to the effect of lomefloxacin in both the day-time and the night-time. The proliferative system of the oesophagus epithelium of the infected mice exposed to lomefloxacin in the day-time proved to be in a noncompensated state and in the night-time it proved to be in the hyperfunctional state.

Monoclonal antibody (MAb) CRC81 against P-selectin, a membrane cell adhesion protein of platelets and endothelial cells (EC), has been obtained and characterized. The antibody selectively interacted with the surface of activated platelets and EC due to the redistribution of P-selectin from intracellular organelles onto the surface by activation. MAb CRC81 could recognize not only human but also rabbit and dog P-selectins. MAb CRC81 was used to establish the heterogeneity of human aorta EC with regard to the P-selectin content. Some of the cells in culture did not contain this protein but were nevertheless positively stained for von Willebrand factor, a specific marker for EC which, similar to P-selectin, is localized in Weibel-Palade's bodies. The proportion of P-selectin negative EC increased dramatically in the course of cell passaging: in primary cultures of aortic EC their content was about 15%, while after the 6th passage it exceeded 90%.

Analysis of the available chronobiological data leads to the following conclusions about the role of biorhythms in the informational interface in living systems: (1) temporal organization of living systems is the main channel of informational interface in organism (the principle of the bond between information and temporal organization); (2) biorhythms or, more accurately, temporal organization of type one postulates the fulfillment of one of the fundamental statements of the general information theory, i.e., correspondence of information to the substratum of its application (the correspondence principle); (3) the biorhythm phases can either unidirectionally strengthen, weaken or realize in different directions the biological potentials of information brought into organism by one and the same material carrier (the principle of amplification, attenuation or inversion of informational potential by biorhythm); (4) biorhythm is the mechanisms driving the transformation of continuous informational signal, if any, into discrete, i.e. the one apt to fulfil a substantial informational stimulus (the quantification principle); (5) as an oscillating reiterative process responsible for reproduction of a biological phenomenon or a biosystem state within nearly equal periods, biorhythm can be viewed as one of the mechanisms of propagation of information in biosystem (the multiplication principle); (6) reproduction of information through biorhythm is one of the universal mechanisms of information survival in biosystem (the information survival principle); (7) aggregation of biorhythms with different periodicity of the same function, i.e. temporal organization of type two, makes it possible for living system to cover a wide frequency spectrum of perception, transmission and replication of signals carrying bio-information with similar semantics, and to make its differential choice when necessary (the principle of optimality of differential choice in perception, transmission and replication of information); biorhythms of an integral whole (temporal organization) is the mechanism underlying the informational interface between biological time of living system and physical time of its environment (the principle of informational interface between biological and physical time).

A concept of the sustainable development principle proposed by the United Nations/International Committee on Environment and Development (ICED, 1987) and gained acceptance at the United Nations Conference on Environment and Development (Rio-de-Janeiro, 1992) lies not in the notion of a sustained character of the development but in an understanding of the development as a steadily and long existing and maintained process that is in advocating the stability of the development. It is known, that the state instability of open self-organizing and self-developing systems including the social ones is the the source of the development having a probabilistic, bifurcate and not quite predictable character. Such an understanding of the development should be well represented in the action initiated in the frame work of national and international state ecological policies.

Using ELISA on fixed endothelial hybridoma (EAhy.926) cells we investigated the occurrence of antiendothelial antibodies (AEA) in the sera from patients with scleroderma systematica (SS) (n = 70) and Raynaud's disease (RD) (n = 19). The mean IgG and IgA-AEA levels were significantly higher in the SS patients than RD patients (p < 0.001) and controls (p < 0.001). We have detected circulating IgG-AEA in 64.2% of patients with SS, 35.2% of SS sera were positive for IgA-AEA. In patients with RD, the frequency of AEA corresponded to that of the random population sample. We have found a high incidence of Raynaud's phenomenon, myositis, telangiectasia and marked digital ischaemia (digital ischemic pulp ulcers, digital scars, osteolysis and autoamputation) among AEA positive patients with SS. AEA-positive patients were characterized by high extent and severity of Raynaud's phenomenon and higher average nailfold capillary microscopy scores. No correlations were found between AEA and different clinical or laboratory parameters, including the type of scleroderma (diffuse and limited), the presence of anti-Scl-7O and anticentromere antibodies and the clinical features of SS (lungs, kidneys and heart involvement, esophageal dysfunction, calcinosis, Sjogren's syndrome). There was no significant correlation between the AEA level and patient age, extent of skin involvement (skin score). Thus, in SS, AEA is associated with a peripheral vasculopathy and represent a useful marker for the diagnosis of endothelial dysfunction.

The ultramicroscopic organization and the endotheliocyte surface relief in ventral portions of the thoracic part of human aorta and in zones of division of blood flow were studied under conditions of early post mortem examinations and perfusion fixation of corpses of 14 humans dead from accidental causes. Zones of entrance into the intercostal aortas are compared with the straight portions of the aorta and are found to be characterized, as compared with the latters, by polymorphism of the endothelium, higher adhesiveness of its surface to blood elements, as well as by the presence of intravitally de-endothelialized portions localized on the ridge of the intimal valve.

Metamorphic rates in Rana temporaria larvae treated with thyroxine and prolactin were observed in different phases of the light-dark cycle. Different hormonal effects on tadpole development were demonstrated depending on the light-dark phases. Thyroxine always accelerated the development. Thyroxine employed at L-D and D-L phases was more effective than in T and D phases. Prolactin retarded metamorphosis in D phase and accelerated in L-D phase. This work demonstrated some temporal relief of hormonal sensitivity of anuran metamorphosis.

The following proteins have been identified in mammalian lung and endothelium, using [32P]ADP-ribosylation by bacterial ADP-ribosyltransferase, immuno- and [alpha-32P]GTP-blottings: 41 kDa Gi1 alpha, 40 kDa Gi2 alpha, 41 kDa Gi3 alpha, 40 kDa and 45 kDa subunits of GS alpha, 36 kDa beta 1 and 35 kDa beta 2 subunits of signal-transmitting GTP-binding proteins (G-proteins), the 19-26 kDa low molecular weight GTP-binding proteins (SMG-proteins) ras, rho, rac, G25K (Gp), as well as ARF and SMG proteins binding with a high affinity to [alpha-32P]GTP. These G- and SMG-proteins are contained in various proportions in membrane and cytosol fractions of lung and endothelium cells. Subunits Gi2 alpha and GS alpha (but not beta 1 or SMG-proteins) my partially (approximately 1%) dissociate from the membrane by the action of the GTP analogs GTP[S] or Gpp(NH)p in the presence of magnesium ions. Extraction with low ionic strength buffer solutions in the presence of EDTA is accompanied by the release of G-actin sensitive to whooping cough toxin Gi2 alpha and beta i subunits. The functionally coupled into a alpha beta gamma heterodimer Gi-protein subunits (predominantly Gi2 alpha and beta i) present in the cytosol fraction as well as the SMG-proteins revealed by [alpha-32P]GTP-blotting (but not the SMG-proteins sensitive to the botulinic C3 exoenzyme, rho/rac, or ARF, may interact with F-actin. Approximately 20% of these proteins are associated with the Triton X-100 insoluble (cytoskeletal) fraction of the endothelium. A conclusion is drawn that interactions of G- and SMG-proteins with actin filaments may be the reason for the formation of "multidisperse" structure in a cell.

The study was made of the effect of various concentrations of chalone-containing preparation from ascitic Ehrlich tumor on DNA synthesis in the tumor. The preparation was shown to suppress DNA synthesis in dose-dependent manner. The dose dependence was characterized by the effect of saturation which is likely to reflect binding of chalone molecules with specific cell receptors.

Circadian rhythms in dog hemostasis were studied in winter. The animals were fed with eleutherococcus and liquorice extracts with bread in different time of the day. Hemostatic investigations revealed chronosensitivity of hemostasis to the phytoadaptogens which is important for assessment of their chronopharmacological properties and prospects of their use.

The content of multinuclear endothelial cells and the ability of cells to incorporate 3H-thymidine were studied in primary cultures isolated from zones of low (LP) and high (HP) probability of atherosclerosis of adult human aortas. It was found that the percentage of multinuclear EC was at mean 2-fold higher in cultures from HP zones compared to LP zones of the same vessels. In primary cultures and in the first passage cultures only small mononuclear EC were able to incorporate 3H-thymidine. A significant decrease in the thymidine index (TI) was found only in cultures from HP zones of atherosclerotic aortas. In cultures of EC from the LP zones of these aortas the TI was as high as in cultures from the LP and HP zones from grossly normal vessels.

The effect of various fractions of chalone--containing preparation from ascyte Ehrlich's tumour obtained by high performance liquid chromatography (HPLC) on mitotic activity and DNA synthesis in the tumour has been studied. After filtration the division of active chalone component which inhibits entering cells into M-phase and S-phase took place. The component inhibiting DNA synthesis eluated with G1-chalone.

Chalone-containing preparation from ascite Ehrlich's tumour blocks these cell transition from G2-phase to mitosis and its motion in mitosis in vitro (G2-block, M-block). Adrenaline blocks these cell transition from G2-phase to mitosis. Propranolol raises G2-block of chalone or adrenaline. Consequently this way of chalones action on cell division includes beta-adrenergic receptors influence of preparation on cell motion in mitosis doesn't change with addition of propranolol. Consequently this way of chalone system action on mitosis doesn't include beta-adrenergic receptors.

The en face organization of human aortic endothelium in zones of low (LP) and high (HP) probability of sudanophilia was examined in preparation impregnated with silver nitrate. It is found that the heterogeneity of endothelial cells (EC) by area is "random" or "clusterized". In the latter case the major part of small and medium-sized EC (less than 800 microns 2) is associated in distinct groups ("clusters") and form foci with high monolayer density. The luminal surface outside the clusters was formed by preferentially large and giant EC. Clusterized endothelium was found with statistically significant higher frequency in HP zones of both "normal" and "atherosclerotic" vessels. The maximum clusterization of EC was revealed on the shoulder region and on the periphery of atherosclerotic plaques which was speculated to be a growth zone of the lesion. It is suggested that the appearance of clusterized endothelium is associated with the active development of atherosclerosis.

Partially purified antichalone and chalone from the liver of the mammals possess significant antiradical activity revealed by the chemiluminiscent analysis in the system capable of generating free radicals. Chemiluminiscent damping degree is proportional to the quantity of antichalone and chalone in the system. During the first three days the activity of antichalone is increased, while that of chalone in decreased in the liver of partially hepatectomized rats. In 14 days after partial hepatectomy the activity of both antichalone and chalone decreased, but their ratio is normalized. Thus, the regeneration of the liver in different periods after the operation takes place when the condition of antichalone/chalone system in the organ is unequal.

The time-space organization of biological systems, cell systems in particular, is one of the most important problems of current theoretical biology having medical implications. The presented view of the general structure of the temporal organization of biosystems and their development in the course of life evolution interprets the temporal organization of a living system as a complex of regular changes in time, the biological rhythms included, its structures and functions which are interactive and show relationships with cyclic alterations of environmental conditions. A special organization is composed of a group of different structures and related functions which are arranged according to a certain pattern in the space occupied by the biological system and interact with each other. The experimental evidence obtained in studies of the proliferative and metabolic systems of the liver, testify to the existence of a general time-space organization in the cell systems. This organization represents an entity formed by the cellular temporal and special organizations and maintained by relationships and interactions between them.

A study was made of the effect of a single injection of hydroxyurea (HU) on the daily rhythm of labelling index (LI) in the epithelial cells of the tongue and esophagus. HU was injected 6 times a day. The degree of decrease in the LI at varying times of the day correlated well with the initial level of the LI. At the same time the number of sensitive cells changed thought the day in a different proportion than LI rhythm, the fact suggesting the independence of these rhythms.

A study was made of the content of alpha-fetoprotein (alpha-FP) in the blood serum and of proliferative processes in hepatoma 22A-bearing mice after injection of cyclophosphamide in a dose of 150 mg/kg at varying time of 4-day tumor growth. The data obtained indicate that the time of appearance of alpha-FP in the blood, the pattern of rhythmic fluctuations in protein content and in the number of DNA-synthesizing and mitotic cells of the tumor depend on the time of the cytostatic injection during the day. Besides, cyclophosphamide exerts a more powerful inhibitory effect on the content of alpha-FP in the blood serum and less powerful on the proliferative processes in hepatoma 22A.

Adrenaline exerts the mitosis-inhibitory effect at a single intraperitoneal administration to mice with Ehrlich's ascites carcinoma. The dose of 1 microgram/g bw produces an effect that lasts over one hour with subsequent normalization of the mitotic index. The doses of 1.5 and 2 microgram provide an effect that lasts during the whole experiment. The changes in the mitotic activity indicate that the tumor reacts to adrenaline by mitosis inhibition and thus retains adrenoreception inherent in normal tissues. The difference in the degree and duration of inhibition after injection of various doses of adrenaline are consequent on their action on specific phases of mitosis.

3H-thymidine was injected to male mice maintained either on a 12 hour light-dark cycle or on a prolonged continuous light (LL-group) at the peak of DNA synthetic activity of the esophagus epithelium (1a. m). The parameters of the diurnal rhythm of cell division and mitotic cycle of the basal layer were studied. In the LL-group of animals, an expressive asynchronization of diurnal rhythm of mitotic index was found. At the same time the labelled cell population revealed a slight degree of asynchronization. The data suggest that the process of asynchronization of the overall kinetics in the tissue throughout the whole day is associated with differences in the state of separate cell populations entering mitotic cycle at the various time of the day. The mitotic cycle duration in both groups of animals is almost alike and equal to 24-27 hours, i. e. is close to that of the diurnal rhythm.

Investigation of the variations in the index of labeled mitoses throughout 90 hours after a single injection to mice of 3H-thymidine at 01 or at 13 o'clock (the periods of the maximal and minimal labeling index in the circadian rhythm of cell proliferation) showed that the cell population which had completed synchronously the mitotic cycle during the first day of experiment also plays the main role in the formation of the peak rhythms in the mitotic index in the following days. The capability of a part of the synchronous population cells to preserve high proliferation rate during several days may be accounted for by the fact that the duration of the mitotic cycle of these cells is comparable with the duration of the rhythm period. The contribution of the asynchronous population into the formation of the peak rhythms in the mitotic activity is insignificant. However, this population proliferates actively enough during the periods of the decreased mitotic index.

The lengths of the synthetic phase (S) and postsynthetic gap plus a half of the mitotic time (G2+1/2 M) has been investigated in hepatocytes of control and thyroxine-treated male white rats using percent labeled mitosis curves after injection of isotope at 10, 16, 22 and 4 o'clock. In the control, the minimum lengths of G2 lasted 3.0 hours without being changed during 24 hours. On the contrary, G2+1/2 M and S varied from 3.2 to 4.4 and from 8.0 to 9.5 hours, accordingly. A prolonged administration or hormone induced changes in duration of all the above phases whose alterations in thyroxine-treated group of animals showed 2.0--3.0, 2.9--3.4 and 6.4--11.3 hours, respectively. During 24 hours, there was observed a characteristic pattern of changes in the labeling index (LI) of both groups of animals. It has been established for both the groups that the increased in LI coincides with the shortening of S-phase. The data allow to conclude that some intracycle mechanisms may exist controlling the cell division and exerting their effects on the cells at the end of G1-phase and during G2-phase. Thyroxine is a regulator of cell proliferation, and its effect was found to occur due to the intracycle mechanisms of cell cycle kinetics.