Effect of adrenalectomy on diurnal rhythm of number of DNA-synthesizing and dividing cells in the mouse lingual epithelium

Diurnal changes in the number of DNA-synthesizing cells and in the number of mitoses were studied in the lingual epithelium of intact and adrenalectomized mice. After adrenalectomy partial desynchronization of mitotic cell division, a decrease in the amplitude of variations in the mitotic index during the 24-h period, and lengthening of the period of increase in the number of mitoses began to occur. The mean diurnal mitotic index in the stratum basale of the lingual epithelium was the same in the control and the experimental series. The rhythm of DNA synthesis in the adrenalectomized mice was the same as in the control. Adrenalectomy thus disturbs the diurnal rhythm of the number of mitoses in the lingual epithelium but does not affect the rhythm of DNA synthesis or the level of proliferative activity.Department of General Biology and Laboratory of Chronobiology, Scientific-Research Center, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Kupriyanov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 479–481, April, 1977.     

Duration of mitosis in the corneal epithelium and spleen cells of mice with leukemia La

The diurnal rhythm of mitosis and its duration were investigated in the corneal epithelium and spleen cells of mice with leukemia La. Correlation was found between changes in the mitotic index and duration of mitosis during the 24-h period. It is suggested that the more rapid course of mitosis in tissues with intensive cell proliferation and its slower course in tissues with low proliferative ability are reflections of a general rule.Laboratory of Chronobiology, Scientific Research Center, and Department of Biology, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 9, pp. 358–359, September, 1977.     

Synchronization of cell proliferation in sarcoma 37 of mice by hydroxyurea

The synchronizing action of hydroxyurea on the passage of sarcoma 37 cells through the S phase and mitosis was investigated in mice, allowing for diurnal fluctuations in mitotic activity and the index of labeled nuclei. The degree of synchronization was estimated from changes in the number of proliferating or labeled cells and the rate of change of synchronization. The tumor consisted of at least two cell populations in which variations in the number of cells both in the S period and also, probably, in mitosis were out of phase. The degree of artificial synchronization of the cells in mitosis based on the rate of change of synchronization was much higher than the natural level in the tumor not divided into separate populations. However, the number of cells undergoing artificial synchronization was not significantly different not only from the number of cells in the tumor undivided into separate populations, but also from the number of cells naturally synchronized in one of the populations. A possible explanation of this fact is that hydroxyurea acted on only one group of cells, for fluctuations in the number of DNA-synthesizing cells in the separate populations also were out of phase.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. Department of General Biology, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1352–1354, November, 1976.     

Autoradiographic analysis of epithelial proliferation in chronic gingivitis

Proliferative processes in the gingival mucosa are studied by autoradiography in 55 patients with chronic gingivitis. It is found that the number of DNA-producing epithelial cells does not change. Increased label intensity in chronic catarrhal and hypertrophic gingivitis in comparison with the control testifies to a sufficient compensatory reaction. Regenerative processes are suppressed in chronic atrophic gingivitis. The number of pathological mitoses increases with the development of pathomorphological changes in all studied types of gingivitis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 10, pp. 473–476, October, 1997     

Enhancement of liver cell proliferation by GM3 ganglioside

In experiments on rats subjected to partial hepatectomy and experimentally induced hepatitis it is shown that GM₃ ganglioside of equine erythrocytes can enhance liver cell proliferation. The effect was also observed in experiments on a primary hepatocyte culturein vitro; moreover, enhancement of cell proliferation did not depend on the type of sialic acid residues. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp 427–430, April, 1995     

Size of lymphocyte subpopulations in the spleen and level of hemopoietic tissue proliferation in mice during surgical interventions

The percent and absolute content of T helpers increases in the spleen of mice 4 and 17 h after resection of the liver or removal of a kidney, which is associated with an increase of the mitotic index of splenocytes. The number of T suppressors and the bone marrow cell mitotic index are unchanged. The T-helper/T-suppressor ratio in the spleen increases 1.7–2 times during surgery on the liver and kidney. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 301–303, March, 1996 Presented by N. K. Permyakov, Member of the Russian Academy of Medical Sciences     

Effect of an inverted light regime on the biological rhythms of the mitotic index of mouse esophageal epithelium in different periods

Changes of the mitotic index in the esophageal epithelium were studied every 20 min for 24 hours in control mice and in mice kept under conditions of an inverted light regime for 10 days. A monophasic circadian rhythm was revealed, which was virtually completely resynchronized to the new light regime after 10 days of photoinversion. Circahoralian fluctuations of the mitotic index with 1–2-hour periods were noted. In controls the period of these fluctuations was shorter in the active phase of the circadian rhythm than during the passive phase. After photoinversion this regularity was no longer observed. Hence, in contrast to the circadian rhythm, the hierarchical structure of the temporal organization of the mitotic index rhythm of the esophageal epithelium in different periods was not restructured during the 10 days of the new light/dark regime. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 94–97, January, 1996     

Changes in hypoxia resistance in rats during daytime

The resistance to acute hypoxia in male Wistar rats was evaluated by the period of survival after exposure to high-altitude hypoxia (11.5 km above see level). The study was performed during daytime (13.00–21.00) in autumn. The fatal rat population was characterized by the log-normal distribution of survival periods. The rats with low and moderate resistance to hypoxia exhibited similar diurnal variations in it with gradual decrease by the end of daytime more pronounced in low-resistant rats. The rats with high resistance showed relatively constant resistance to hypoxia which decreased only at 21:00. All groups revealed a relatively stable resistance to hypoxia from 16:00 to 18:00. These variations in the resistance to hypoxia should be taken into consideration when planning experimental research. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 256–260, March 1999     

Changes in mitotic activity in the corneal epithelium of rats of different ages after nociceptive stimulation

The effect of nociceptive stimulation on mitotic activity in the corneal epithelium was investigated in 21-day-old rat fetuses and in rats aged 3, 4, 5, 7, 10, 15, 20, and 25 days. Mitotic activity was not significantly changed 45 min after nociceptive stimulation of the animals (amputation of one-third of the tail) in the corneal of the fetuses and day-old rats. Between the 3rd and 10th days of postnatal development reactive inhibition of mitosis in response to nociceptive stimulation was gradually formed. After 10 days this response was intensified and reached a maximum by the 25th day. Reactive inhibition of mitotic activity is connected with delayed entry of the cells into mitosis.Department of General Biology, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Kupriyanov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol 82, No. 11, pp. 1367–1369, November, 1976.     

Stimulation of the DNA replication and murine bone marrow cell proliferation with exogenous zinc-metallothionein

It is shown that zinc-metallothionein from rat liver increases 1.5-fold thein vitro incorporation of³H-thymidine in murine bone marrow cells. The same concentrations of zinc chloride and a mixture imitating zinc-metallothionein (zinc, cysteine, and albumin) inhibit DNA synthesis. In mice receiving an intraperitoneal injection of zinc-metallothionein 10–15 min before γ-irradiation, the incorporation of³H-thymidine and the content of nucleated cells in the bone marrow is 1.5- to 2-fold higher than those in unprotected animals, the number of endogenous splenic colonies in pretreated mice being 2.7-fold higher. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 11, pp. 505–508, November, 1996     

Effect of synthetic analogs of dermorphin on mitosis in the corneal and lingual epithelium of albino rats

A study of the effects of synthetic analogs of dermorphin which are prime agonists of the μ-opiate receptors, on cell division in the corneal and lingual epithelium of albino rats showed that both analogs depressed DNA synthesis in the corneal and lingual epithelium 4 h after administration. In the lingual epithelium DNA synthesis and the mitogenic index were still depressed 24 h after drug administration. In the cornea cell division parameters had normalized by this time. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 508–510, November, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

The past,present, and future of research on the regulation of nonlymphoid cell proliferation by lymphoid cells

Reviewed are data on the capacity of T lymphocytes to stimulate or inhibit nonlymphoid cell proliferation, on the correlation of this capacity with the activity of respective immunoregulatory cells (T helpers and suppressors), and on the possible cell-mediated and humoral mechanisms through which lymphocytes execute their morphogenic function. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 230–234, September, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Synchronization of cell proliferation in the esophageal epithelium of mice with tumors by hydroxyurea

The synchronizing action of hydroxyurea on the passage of esophageal epithelial cells through the S phase and mitosis was investigated in mice with tumors, making allowance for diurnal fluctuations in the number of these cells in particular phases under natural conditions. To evaluate synchronizationin vivo two complementary criteria reflecting changes in the number of cells and the rate of change of synchronization are suggested. In artificial synchronization, two groups of cells passing synchronously through the S phase and mitosis were formed in the esophageal epithelium. The degree of artificial synchronization of the first group was less than natural. The number of cells in the second group in the period of DNA synthesis was twice the number of cells synthesizing DNA during natural synchronization, but the rate of change of synchronization was the same in the experimental and control groups.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 6, pp. 760–762, June, 1976.     

Effect of phenibut on the formation of the respiratory rhythm

In experiments with Nembutal-anesthetized cats of both sexes, the drug phenibut administered intravenously was found to elicit periodic apneic respiration and to rank between baclofen and sodium oxybutyrate in terms of the ability to disrupt the respiratory rhythm. It is suggested that these three activators of the gamma-aminobutyric acid (GABA) system produce differential effects on GABA_B receptors (baclofen>phenibut>oxybutyrate in order of decreasing effectiveness) and participate in the formation of the respiratory rhythm, and that in activating this system they can give rise to irregular slowed respiration with pauses at inspiration. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 606–609, June, 1995 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Instability of bronchial epithelium in chronic pulmonary diseases

Pathomorphological examination of large bronchi in patients with occupational diseases, lung cancer, and in subjects exposed to radiation revealed structural and functional heterogeneity of the epithelium: the presence of focal atrophy, metaplasia, hyper- and dysplasia in the same biopsy specimen. This phenomenon was termed as instability of the epithelium. Thickness of the epithelium greatly varied, especially, in neoplastic processes. Atrophy and epithelial instability phenomenon are interpreted as morphological markers of ecological and oncological risk. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 470–474, April, 2000