Migration and proliferation of smooth muscle cells (SMC) were studied in cultures prepared from the aorta of Wistar male rats (170—200 g b.w., 8 weeks old) raised under conventional (CC) or specific pathogen-free (SPF) conditions. In primary cultures, higher movement of cells from explants was found in CC raised donors, namely in samples cultured in serum incomplete medium. In the following subcultures (passage 3—16), the growth curves were steeper and the doubling time shorter in CC type of cultures. The faster growth of SMC population from conventional donors was found to be due to a shorter cell cycle and a higher proportion of dividing cells. As a consequence, the maximum population densities were also higher in the latter type of cultures. The differences in growth, that were dependent on raising conditions, were evident for 16 passages, i.e. 7 months after explantation of cells into culture. The data suggest that breeding conditions may affect the activation of growth of SMC in blood vessels in situ.
An allogeneic reaction among brain cortex cells (mixed reaction) was demonstrated previously by H-2 alloantigen- induced uncoupling of oxidative metabolism (Kovářů Med. Biol. 58: 273, 1980). In the present study we have demonstrated that alloantigen already increased cell surface Na + ,K+-ATPase activity after 100 min when the enzyme activation was highest at Mg2+/ATP ratio 4: 1. The allogeneic cell reaction was accompanied by an elevation of membrane lipid fluidity and probably also by a thermotropic lipid phase transition which might influence the membrane lipid-dependent Na+,K+-ATPase activity, while Mg2+-ATPase remained unaffected. Furthermore, the effects of proteins and peptides released into the supernatant during the allogeneic reaction were analyzed in brain cortex cells. One of the isolated active peptide fractions, Fa (m.w. lower than 2.5 kD), was able to enhance Na+,K+-ATPase activity as well as to block K+-evoked O2 uptake by brain cortex cells. Thus the Fa fraction simulated primary allorecognition events. The data indicate that various brain cell surface domains were influenced by a regulatory peptide fraction of the cytokine type during the early phase of allogeneic reaction. Allorecognition among brain cortex cells is directed against functionally important metabolic reactions.
Sodium borocaptate (BSH, Na2Bi2HnSH), a slow neutron-capture compound, was injected into the left forebrain ventricle of 1-week-old rats (150 fig BSH/3 p\ phosphate buffered saline). After 90 min, the animals were irradiated by epithermal neutrons (LVR-15 nuclear reactor in Řež near Prague, flux density 8.8 x 107 neutrons cm-2 s'1, 8 MW reactor power, 8.2 cGy/min) for 5,10 or 20 min. The brains were examined histologically 8 h after irradiation. In animals irradiated for 5 to 10 min (41 and 82 cGy-Eq, respectively) lethal damage of cells was found in the external granular layer of the cerebellum and the subependymal layer of the forebrain. Irradiation for 20 min (164 cGy-Eq) caused more extensive destruction of cell populations in these regions and, in addition, dead cells appeared also in the more differentiated postmitotic compartments, namely the deeper layers of the cerebellum, layers II/III of the cerebral cortex and corpus callosum. In the forebrain periventricular layer, the extent of cell damage was declining towards the olfactory bulbs. In intact animals, as well as in those injected only with the 150 p\ phosphate buffered saline, the radiation damage was low and limited only to the most sensitive dividing populations of the cerebellum and the forebrain. The study demonstrates a differentiation-dependent damage of the rat brain cells by alpha particles and presents a simple model for evaluation of the biological effectiveness of slow neutron beams constructed for neutron-capture therapy of tumors.
Ergot alkaloids (EAs), products of Claviceps spp., are widely used in various fields of clinical medicine (neurology, psychiatry, endocrinology). In the present work we studied the neuroimmunomodulative effect of EAs on activation of NK cells and their signalling pathways. Furthermore, the killing capability of rat NK cells in vitro was examined in the presence of glycosidic derivatives of elymoclavine, agroclavine, and liposome-encapsulated EAs. The engagement of appropriate NK cell membrane receptors by EAs cause an indirect enhancement of adenylyl cyclase system through inhibition of G-protein a 1,2-subunit (up to 50 % of control values). All of the tested EAs enhanced the rat NK cell-mediated cytotoxic activity in vitro, particularly against target cells of astrocyte origin (C-6 glioma). The present results argue for a possible EA immunomodulatory role of cell-mediated immunity in tumour regression processes.
The paper reviews neutron sources, chemical compounds and clinical perspectives of the boron neutron-capture therapy of brain tumours. Special attention is paid to the physical characteristics and biological effectiveness of the epithermal neutron beam constructed at the LVR-15 nuclear reactor at Řež near Prague.
This study describes the effects of cytokine peptides released into the supernatant during an early allogeneic reaction (AR) of mouse spleen lymphocytes or brain cortex cells which differ in their major histocompatibility complex (MHC). The peptides were isolated by ultrafiltration, liquid chromatography and HPLC. We found that both peptides stimulated the cell surface Na+,K+-ATPase and Ca2+-ATPase activities of quiescent spleen lymphocytes in vitro and mimicked early allogeneic cell interactions. Both brain and spleen AR peptides inhibited Concanavalin A-stimulated spleen lymphocyte proliferation, whereas 3H-TdR incorporation into DNA of the E7 neuroblastoma cell Une was stimulated by these peptides. The peptide isolated from the supernatant of the allogeneic brain ceU reaction inhibited phagocytosis in phorbol myristate-stimulated LA5-9/8 mouse macrophage cell line. Immunosuppressive activity of spleen AR peptide is supported by inhibition of spontaneous E rosette formation by lymphocytes. The immunosuppressive effect of isolated peptide cytokines on lectin-activated lymphocytes was comparable with the serum thymic factor (FTS, Lenfant et al. 1983). These changes demonstrate the pleiotropic cytokine actions mediated by plasma membrane of immune system and brain cells.
3H thymidine was injected into pregnant mice in order to label the DNA in the dividing Purkinje cell (PC) precursors of the embryonic cerebellum. The retention of 3H-DNA was evaluated in PC nuclei of animals at the age of 25 days, 3, 6 or 9 months by light microscope autoradiography. The number of silver grains decreased in the whole nuclei by 13.6 % and 19.6 % in animals 6- and 9-month-old, respectively. In the nucleolar region, the loss of DNA radioactivity was more profound; the silver grain counts decreased by 22.6 % and 29.1 % in 6-and 9- month-old animals, respectively. No significant differences in the volume and dry mass concentration were found in the PC nuclei of 25 PD and 9 PM old animals. Therefore, the observed changes in grain density counts represent the actual measure of 3H-DNA loss, and /or "spontaneous" renewal of the DNA molecule in PC nuclei, as well as its higher expression in the nucleolar region. Furthermore, it follows from the comparison of our data with those present in the literature, that DNA synthesized in nerve cell precursors before their withdrawal from the mitotic cycle is more stable than that synthesized in postmitotic neurones. This suggests that the repair of DNA in mature neurones might be of an error-prone type.
The morphology and proliferation of vascular smooth muscle cells (VSMC) were studied in cultures prepared from the aorta of newborn male and female Wistar rats. The doubling times (DT) of the male-derived population were 16.4 ±0.7 h and 30.0 ±2.2 h in the exponential and post-exponential growth phases, respectively. In the female donor cells, the corresponding DT values were significantly longer, i.e. 21.9 ± 1.8 h and 38.0 ±2.2 h. In addition, the period of growth was shorter in the female-derived cultures. The percentage of 3H-thymidine labelled cells in male cultures was 61.0±3.1, 92.8± 1.9 and 98.7±0.6 % at 2, 27 and 52 h, respectively. In the female-derived populations, only 24.6 ±4.4, 66.1 ±3.8 and 82.8 ±2.0 % of cells were labelled at the corresponding incubation intervals. As a consequence, the final population density in male cultures was 5.6 times higher. In addition, the male-derived VSMC were mainly spindle-shaped and bulgy in appearance while those from female donors were flat and polygonal which means that the cells were adhering to the growth support to a different extent. The study revealed early determination and long-term persistence of lower adhesiveness as well as higher growth potential of male VSMC, i.e. properties which may be of importance for explaining the higher incidence of vascular wall disorders in males.
Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1b), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1b have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1b on brain γ-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 μg IL-1β or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1β. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1b administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1b induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.