Peculiarities of bone marrow hemopoiesis in early aging OXYS rats.

Colony-forming activity of bone marrow cells in 3- and 12-month-old Wistar rats does not differ by the number of early and erythroid precursors and by the formation of granulocyte-macrophage colonies. In senescence-accelerated OXYS rats, the number of early and erythroid precursors significantly increases by the age of 12 months and surpasses the corresponding values in Wistar rats. The number of granulocyte-macrophage colonies in OXYS rats does not change with age, but the numbers of these colonies formed at the age of 3 and 12 months in these animals are higher than in Wistar rats. As a result, the total number of hemopoietic colonies in 12-month-old OXYS rats 2-fold surpassed that in 12-month-old Wistar rats. Activation of granulopoiesis and increased numbers of early and erythroid precursors indicate deep changes in the functional status of the hemopoietic stem cell in 1-year-old OXYS rats in the direction characteristic of aging animals.

Cell cycle of bone marrow CD34+ cells during autoimmune disease development in MRLMpJ/lpr mice.

The development of autoimmune disease in Fas-deficient MRLMpJ/lpr mice is associated with a relative decrease in the content of bone marrow CD34+ cells, which can attest to intensification of migration of early hemopoietic precursors from the bone marrow. The intensity of CD34+ apoptosis is high in young healthy MRLMpJ/lpr mice in comparison with the control, but decreases during the development of autoimmune disease. Proliferative activity of CD34+ cell population surpassed the control in all mouse groups, except AID2. The detected shifts in quantitative and qualitative parameters of CD34+ cells attest to an important role of stem hemopoietic precursors in the formation of autoimmune disease in MRLMpJ/lpr mice.

Formation of immunodeficiency in newborn mice exposed to nicotine during intrauterine development.

Exposure to nicotine during intrauterine development leads to immunodeficiency manifested in inhibition of delayed-type hypersensitivity reaction and reduced number of antibody-producing cells forming in response to sheep erythrocytes in newborn mice. The number of splenic CFU in the bone marrow of newborn mice exposed to nicotine in utero is decreased compared to the control. By contrast, nicotine induced an increase in splenic CFU count in fetal liver. We concluded that nicotine modifying the hemopoietic microenvironment delayed the release of primitive precursors from fetal liver, which impaired colonization of fetal bone marrow and led to imbalance in the production of mature blood cell, including immune system cells.

DNA-hydrolyzing antibodies from sera of autoimmune-prone MRL/MpJ-lpr mice.

Catalytically active antibodies (abzymes) hydrolyzing proteins, polysaccharides, ATP, DNA, and RNA have been detected in the sera of patients with various autoimmune and some viral diseases, but abzymes from the sera of animals are practically unstudied. The development of lupus-like autoimmune disease of MRL/MpJ-lpr mice is an experimental model for study of autoimmune pathologies and immunopathogenesis. In this work, homogeneous IgG preparations were isolated from the sera of MRL/MpJ-lpr mice. These antibodies (Abs), their Fab-fragments, and isolated light chains were shown to possess catalytic activity in DNA hydrolysis, whereas Abs from the sera of control healthy mice did not hydrolyze DNA. The data demonstrate that DNA hydrolyzing activity is an intrinsic property of Abs from MRL/MpJ-lpr mice. It was shown that various markers of autoimmune pathologies (level of total protein concentration in urea (proteinuria), Abs titers to native and denatured DNA, and DNA-hydrolyzing activity of IgG) increased in animals with aging, but they noticeably increased (2-22 times) only after appearance of obvious indicators of pathology independently of age. The highest increase in proteinuria (25-fold), anti-DNA Abs titers (12-19-fold), and abzyme activity (120-fold) was found in mice after their immunization with DNA-protein complex.

Role of G-proteins and second messenger systems in the plasticity of a defensive reflex in the common snail.

Enzymatic methods were used to demonstrate an increase in the activity of G-proteins and protein kinase A in the brain of the common snail at early stages of learning. There were no differences in the activity of G-proteins in the brain between young (unable to learn) and adult snails. Snail brain protein kinase C activity was unchanged compared to controls 20-40 minutes after the end of the training procedure. It is concluded that cAMP-dependent phosphorylation and cAMP-dependent activation of early gene expression have active roles in learning in the snail. The question of the role of additional intracellular regulatory systems in learning in the snail is discussed.

[The role of G-proteins and second messenger systems in the plasticity of the avoidance reflex in the snail]. / Rol' G-belkov i sistem vtorichnykh posrednikov v plastichnosti oboronitel'nogo refleksa u vinogradnoi ulitki.

An increase in the activity of G-proteins and protein kinase A was shown in the brain of Helix at the early stages of learning. The protein kinase C activity did not differ from the baseline in 20-40 min after training. There was no difference between the brain G-protein activities in the young (unable to learn) and adult snails. A conclusion is drawn that the system of cAMP-dependent phosphorylation and cAMP-dependent activation of the early genes actively participate in learning of Helix. The participation of additional systems of intracellular regulation in learning is discussed.

[Changes in the lactate dehydrogenase isoenzyme spectrum during T-lymphocyte differentiation]. / Izmenenie spektra izofermentov laktatdegidrogenazy v protsesse dfferentsirovki T-limfotsitov.

The pattern of lactate dehydrogenase isoenzyme spectrum changes on different stages of T-lymphocyte differentiation was studied An enriched population of stem cells has LDH-5, 4 and 3 isoenzymes, and much less LDH-2 activity. The isoenzyme pattern of thymic cell precursors consists of LDH-5, 4, 3 and 2. All the five LDH isoenzymes were found in cortical thymocytes. Medullary thymocytes reveal LDH-5, 4 and 3 isoenzymes. T-lymphocytes of peripheral lymphoid organs contain mainly LDH-5 and in a lesser degree LDH-4 activity.

[Analysis of lactate dehydrogenase isoenzymes in murine lymphocyte populations]. / Analiz izofermentov laktatdegidrogenazy v populiatsiiakh limfotsitov myshei.

The pattern of lactate dehydrogenase isoenzyme has been examined for different murine lymphoid cell populations and for T and B lymphocyte populations. LDH-1, LDH-2, LDH-3, LDH-4 and LDH-5 were found in the thymus, LDH-3, LDH-4 and LDH-5 in the spleen, and LDH-4 and LDH-5 in lymph nodes. Enrichment of lymphocytes with T and B cells resulted in the appearance of LDH-4 and LDH-5 in T cell population, and of LDH-5 in B cell population. With the appearance of the autoimmune reaction, activity of LDH-5 in the thymus was seen to decrease. After the thymosin injection (4 fraction), activities of LDH-1, LDH-2 and LDH-3 diminished. A possible application of the LDH isoenzyme distribution pattern as a marker of T cell differentiation is discussed.