Adaptation to intermittent fasting as a factor modifying the radiation resistance of mice.
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Animals↗
Biomedical subjects
M Pospísil
Publications and source records attributed to M Pospísil.
Characterization of antigen-specific receptors from pig lymphocytes.
Antigen-specific receptors were isolated from the surface of spleen and lymph node cells of ARS-BGG-stimulated miniature pigs using an immunoadsorption technique. The yields of the receptors can be increased by 20-hr cultivation of the cells protein-free medium prior to the isolation procedure. In this case antigen-specific molecules can be isolated not only from the surface of the cells but also from the culture medium. 125I-labelled isolated receptors were separated by SDS-PAGE into six fractions. The first corresponded to aggregated molecules and IgG, the mol. wts of the other fractions were 56,000, 35,000, 26,000 and 10,000. It has been shown that they all were able to bind antigen but only the first two reacted with anti-Ig antibodies and Staphylococcus aureus protein A-Sepharose 4B. Gel filtration of the same sample of 125I receptors on Sephacryl S-200 revealed the presence of four peaks. Three of them were able to bind antigen as detected by radioimmunoassay. Fractions of all three peaks reacted also with anti-Id and anti-R (anti-Ig- receptors) antisera, but only fractions of the first two peaks reacted with anti-Ig antisera. The finding that Ig- receptors and more heterogeneous than Ig+ receptors is discussed. No reaction of isolated 125I receptors with anti-SLA and anti-SLB antisera used was detected in the solid-phase radioimmunoassay.
Animals↗
Protective effect of intermittent fasting on the mortality of gamma-irradiated mice.
The effect of 1 to 6 weeks' adaptation to intermittent fasting (alternating periods of 24 h fasting and subsequent 24 h feeding) on the manifestations of radioresistance of mice subjected to whole-body gamma-irradiation was studied. A favourable effect of this feeding regimen on the survival of irradiated animals was observed. The optimal radioprotective effect was achieved in mice adapted to intermittent fasting for 2 to 3 weeks and irradiated after 24 h of food intake. Furthermore, it was shown that the radioresistance of the adapted organism depends on the momentary state of food intake. After renewal of the normal ad libitum feeding the adaptively induced radioresistance decreases.
Animals↗
[Causae mortis in injured persons with fractures of upper end of femur (author's transl)].
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Aged↗
Inhibition of entry into S phase and DNA synthesis in bone marrow cells of mice by repeated injections of gentamycin.
The effect of gentamycin on bone marrow cells in unirradiated and irradiated mice was investigated by 3H-dTh incorporation into DNA using microautoradiography. Gentamycin was injected in vivo at 20 mg base/kg body weight at 8-h intervals during three days. In mice exposed to 4.78 Gy the injections of gentamycin were started on the 7th day after irradiation. In granulopoietic and erythropoietic cells the inhibition of entry of cells into S phase and the retardation of DNA replication was about 20%. The roughly 30% inhibition of entry of cells into S phase observed when the bone marrow cell population has been evaluated as a whole is discussed in terms of increased sensitivity of the young blast-like cells.
Animals↗
The effect of chloramphenicol on erythropoiesis in X-irradiated mice.
Mice irradiated with a dose of 4,78 Gy X-radiation were treated 3 or 5 days with a thrice-daily dose of chloramphenicol of 160 or 320 mg/kg. Observation of the incorporation of 59Fe into the heme fraction suggested that chloramphenicol has a depressive effect on erythropoiesis in the spleen of nonirradiated animals, and clearly proved this in irradiated ones. Depression in the bone marrow of nonirradiated animals was not observed, in irradiated animals a depressive effect was shown, though less strong than in the spleen. As benefits these findings there is an accentuation of postirradiational anemia after chloramphenicol treatment of irradiated animals, and signs of incipient anemia in nonirradiated animals. All the effects mentioned were repaired within 14 days of the end of chloramphenicol treatment.
Animals↗
Comparison of cell proliferation in the regenerating bone marrow and spleen of irradiated mice with the use of 125I-iododeoxyuridine.
The method of 125IUdR labelling of hemopoietic cell populations was used to estimate differences of repopulation kinetics in the femoral bone marrow and spleen of sublethally irradiated mice. In regenerating bone marrow the cellularity and proliferation index, as measured by 6 h 125IUdR incorporation, were found to be inversely related. In the spleen the proliferation index increased parallelly with the increase in cellularity and indicates an ineffectiveness of a change in the set point of local cellularity control. Experiments with measuring the retention of 125IUdR in hemopoietic organs revealed, in the spleen of irradiated animals, phases of increased cell losses as well as immigration of labelled cells into this organ.
Animals↗
[Quantitative cytological findings in mixed milk samples].
In two cow-houses (fifty cows in each), 5851 udder-quarter samples were subjected to cytological examination (by the Coulter Counter electronic computer) and to bacteriological examination during a ten-month period; the cytological examination was also performed with 141 can milk samples. The mixed samples in which the number of cellular elements does not exceed the level of 500 thousand ml-1 do not indicate reliably whether the milk comes from healthy udder quarters or contains an admixture of secretion from the diseased quarters. A value of above 500 thousand cellular elements per ml in mixed samples only suggests that the milk probably contains more secretion from infected udder quarters. The number of cells in the mixed samples does not constitute a basis for the conclusion concerning the number of quarters with impaired secretion which contributed to the sample, because the number of cells in the mixed samples depends also on the degree of disease in the respective quarters. An amount up to 500 thousand cellular elements per ml in the mixed sample provides practically no useful and usable information on milk quality. If the number of cellular elements per ml is higher than 500 thousand, this information is only suitable for revealing the stables with a high occurrence of mastitis--it is just a signal, not a parameter of such a situation. It is from this aspect that all results should be evaluated at those places where only mixed samples can be examined.
Animals↗
Erythrocytic and granulocytic differentiation of transplanted bone marrow cells in mice treated with thyroid hormones.
Feeding of C57BL mice with dried thyroid glands (added to their food) for 10 days activates 59Fe incorporation into splenic heme and decreases peripheral granulocyte levels. The importance of the differentiation of haemopoietic stem cells under these conditions was investigated by using the repopulation assays. Transplantation of bone marrow cells into recipients irradiated on day 10 of treatment with thyroid hormones, i.e., in the phase of activation of erythropoiesis, results in an increase in erythropoiesis and a decrease in granulopoiesis. However, following irradiation and transplantation of animals during the phase of rebound, i.e., approximately 5-8 days after cessation of thyroid hormone treatment, erythropoiesis is depressed and granulopoiesis is activated, the values exceeding markedly the control levels. The practical importance of changes in the host inductive milieu favouring granulopoiesis is documented by the results showing that hormonal marrow has an increased capacity to prolong the survival of animals lethally irradiated in the phase of rebound after pretreatment with thyroid hormones.
Animals↗
Immunogenetic studies in semi-inbred pigs.
Seventy-six siblings from 11 semi-inbred families of Landrace pigs (inbreeding coefficient 0.70-0.82) were used for transplantation of skin and renal allografts. The animals were selected with regard to the major histocompatibility complex SLA, alloantigenic systems SLB, SLC and blood groups. Using the test of the difference in mean level between two groups of observations, the influence of compatibility in the E blood group system on the survival of transplants was proved. The observed difference suggests that the E blood group complex or a linked locus behaves as a minor histocompatibility system. The induction of tolerance in piglets treated and non-treated with allogeneic sera from long-term liver recipients was also investigated. Large doses of sera did not exert any effect on skin graft survival.
Alleles↗
The effect of dietary administration of aspartic acid on thymus weight in C57 black mice.
D,L aspartic acid incorporated at a level of 0.5% w/w into the diets of C57B1/10 male mice for 2--8 weeks increased significantly the thymus weight. Similar effects were observed after a 10 days' treatment of the mice with K- and Mg-salts of D,L aspartate (1%) in drinking water.
Administration, Oral↗
Chloramphenicol toxicity in radiation disease.
The effect of chloramphenicol given in high therapeutic doses, in the course of postirradiation syndrome in irradiated mice of C57Bl/10 strain, is reported. Chloramphenicol treatment increased postirradiation mortality of animals and intensified suppression of the proliferating and differentiating processes in hemopoietic organs of the irradiated animals. The results support the assumption that postirradiation depression of hemopoiesis is a contraindication to the therapeutic employment of this antibiotic.
Animals↗
Influence of the thyroid hormones on erythropoiesis and radiation resistance in C 57 black mice.
Oral administration of dried thyroid gland to C57Bl adult male mice in a dose of 0.6 g per 100 g diet during 10 days increased the metabolic rate and stimulated the erythropoiesis. Three to six days after thyroid pretreatment the radiation resistance of the mice increased, as revealed by their 30-day survival and a higher recovery of peripheral blood cell counts. The period of increased resistance to radiation was correlated with the receding of hypermetabolic effects and with the increase of repopulating abilities of the bone marrow cells.
Animals↗
The evaluation of palliative effects of sympathectomies in the comprehensive treatment of sequelae of internal carotid obliterations. Clinical and statistical results.
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Aged↗
Effect of low molecular factors released during allogeneic interactions of leucocytes or brain cells on PHA- and LPS-induced DNA synthesis in lymphocytes.
Male (A/Ph and C3H/Cbi/BOM) mice were used in our experiments. The cell-free supernatants of spleen mixed leucocyte cultures and allogeneic brain cortex cells were collected upon short-term incubation and tested in a comparative study. Spleen and brain low molecular factors were fractionated (ultrafiltration and gel column chromatography) and assayed for their activity in mitogen-induced 3H-thymidine incorporation into spleen lymphocytes. The specific release of the allogeneic spleen fraction (ASF-2) has been observed. A non-specific stimulating effect of ASF-2 on PHA- and LPS-activated spleen lymphocytes was shown. In contrast, a non-specific suppressive effect of brain fraction on PHA- and LPS-stimulated lymphocytes was demonstrated. The opposite effects of spleen and brain factors can be connected with their different composition. The lymphocyte cultures were not affected by spleen or brain factor, when cultured without the addition of mitogen. Positive and negative regulation or modulation of triggering events in lymphocyte activation by these factors can be suggested.
Animals↗
Immunosuppressive properties of the antibiotics cytostipin and vermiculine.
The properties of two antibiotics, cytostipin isolated from Penicillium stipitatum and vermiculine isolated from Penicillium vermiculatum, were examined in two systems for a rapid screening of current immunosuppressive agents [nucleolar test determining the degree of RNA synthesis in nucleoli of individual lymphocyte populations, and the reactivity of mouse lymphocytes to "T" (PHA) and "B" (LPS) mitogens]. Both antibiotics, distinctly suppressed the increase in number of "active" lymphocytes with compact nucleoli in the popliteal lymph node activated by SRBC. Incorporation of 3H-uridine into PHA-stimulated "T" lymphocytes was suppressed by both antibiotics, incorporation into LPS-stimulated "B" lymphocytes was inhibited by cytostipin but stimulated by vermiculine. The antibiotics were also tested in another two "classic" immune systems, the Jerne test and the GVH reaction. Both antibiotics in doses markedly inhibitory for GVH reaction did not suppress but significantly increased the number of the haemolytic plaques in spleens of SRBC-immunized mice.
Animals↗
Effect of K and Mg aspartates on spleen erythropoiesis in mice.
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Animals↗
Effect of K and Mg salts of aspartic acid on haemopoiesis and recovery from radiation damage in mice.
Male mice of a non-inbred strain "H" were used to verify the effect of a 10-day peroral administration of K and Mg aspartates on haemopoietic functions. The salts were proved to stimulate the proliferation and differentiation processes in the thymus, bone marrow and spleen tissues. Mice exposed to a single whole-body X-irradiation after pretreatment with K, Mg aspartate exhibited a more conspicuous postirradiation regeneration of haemopoietic organs and an increased postirradiation survival. The results suggest the possibility of using K, Mg aspartate for radioprotective purposes.
Animals↗