Sensitivity to hypobaric hypoxia in mice selected for high and low brain weights

We studied the effect of hypobaric hypoxia on mice with various brain weights. Mice with low brain weight were more resistant to hypoxia than animals with high brain weight.     

Morphometric peculiarities of the brain in two-month-old rats as a function of body weight at the age of one month

The brain from 2-month-old rats up to the age of 1 month was studied in litters of different size: 9–13 (control) and 4–6 (reduced) animals. In animals from reduced litters the absolute weight of the brain surpassed that of controls. The maximum brain weight is characteristic of animals from reduced litters with maximum body weight at the age of one month, while the minimal brain mass is found in controls with the minimal body weight. There are no differences in the cortical thickness and neuron density in layers II and V between these two groups. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 115–117, July, 1997     

Significance of various adrenoreceptors for brain resistance to total ischemia

In contrast to the β-agonist isoprenaline and the α₁-agonist phenylephrine, the α₂-agonists clonidine, guanobenz, and methyldopa are highly effective against total brain ischemia. Epinephrine in itself is inactive but displays protective activity against the background of the β-antagonist propranolol. The α₂-antagonist rauwolscine, but not α₁-antagonists, abolish the protective effect of clonidine. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, № 2, pp. 156–158, February, 1996 Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

Glutathione S-transferase activity in the liver of mice with different sensitivity to hepatocarcinogenic effects ofo-aminoazotoluene

Glutathione S-transferase activity was detected in the liver of inbred mice sensitive (CBA) and resistant (CC57BR and C57B1) to hepatocarcinogenic effects ofo-aminoazotoluene. High liver glutathione S-transferase activity was found in CC57BR and C57B1 and low in CBA mice treated with this carcinogen. Thus, interstrain differences in glutathione S-transferase activity probably determine the resistance too-aminoazotoluene-induced hepatocarcinogenesis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 2, pp. 174–175, February, 2000     

Functioning of hypophysial adrenocortical system in rats selected by the threshold of sensitivity to electrical current

An enhancement of stress reactivity of the hypophysial-adrenocortical system in response to emotional and physical influence was shown in rats with a low threshold of sensitivity to electrical current. This phenomenon was observed as a rise in the maximum level of blood corticosterone and acceleration of stressor hormonal response. In the high-threshold rats a decrease in sensitivity of the hypophysial adrenocortical system to the feedback signals was observed. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 4, pp. 443–445, April, 1998     

Effect of hyperlipidemia on thymocyte sensitivity to apoptosis in CBA and C57Bl/6 mice

Effects of experimental hyperlipidemia on apoptosis and proliferation of thymocytes in response to mitogens were studied in CBA and C57Bl/6 mice. The concentrations of cholesterol in the serum and thymocyte membranes increased in both mouse strains. Spontaneous and dexamethasone-induced apoptosisin vitro and the proliferative response to phytohemagglutinin and concanavalin A were enhanced in thymocytes from C57Bl/6 mice and suppressed in cells from CBA mice. These data suggest opposite reactions of thymocyte to increased serum cholesterol concentration in these two strains, associated with stimulation and suppression of cell activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 200–202, August, 2000     

Correlation of pain sensitivity and the humoral immune response in mice during thermal stimulation

A hypothesis about a correlation between threshold pain sensitivity and antibody production is proposed and experimentally validated. Immunodeficient mouse strains are characterized by a higher threshold sensitivity to pain than animals with a normal immune response. A highly reliable negative correlation between threshold sensitivity to pain assessed by the hot plate test and the number of antibody-producing cells in the spleen after immunization with sheep red cells is observed in 77% of (CBA×C57B1/6) F₁ mice examined. The negative correlation is observed both in spontaneous variations of threshold pain sensitivity and during an elevation of this threshold under the effect of preceding nociceptive stimulation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 405–408, April, 1995 Presented by R. V. Petrov, Member of the Russian Academy of Medical Sciences     

Activity and inducibility of cytochrome P-450-1A in the liver of mice with different sensitivity to hepatocarcinogenic effect of o-aminoazotoluene

Specific activity of cytochrome P-450-1a is detected in the liver of 7 inbred mouse strains sensitive (SWR, C3HA, DD, and CBA) and resistant (AKR, CC57BR, and C57BL) to o-aminoazotoluene-induced hepatocarcinogenesis: 7-ethoxyresorufin-O-diethylase and 7-methoxyresorufin-O-dimethylase, induced by benzo(a)pyrene and o-aminoazotoluene. Mice sensitive (CC57BR and C57BL) and resistant (AKR) to P-450-1a induction were resistant to induction of liver tumor and, similarly, mice both resistant (SWR and DD) and sensitive (C3HA and CBA) to P-450-1a induction were sensitive to hepatic tumor induction. Therefore, there was no correlation between inducibility of cytochrome P-450-1a and sensitivity to o-aminoazotoluene-induced hepatocarcinogenesis at the initial stages of chemical carcinogenesis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 8, pp. 201–203, August, 1998     

Seasonal differences in the development of heightened resistance of the isolated heart during adaptation to physical exercise

Substantial seasonal differences are found in the development of the cardioprotective effect of adaptation to physical exercise: in winter such adaptation results in an increase of the resistance of the isolated heart to the contracture and arrhythmogenic effects of ischemia and reperfusion, while in summer the anticontracture effect is absent and the antiarrythmic effect is significantly lowered. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 299–301, September, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Differential sensitivity of selected brain areas to excitatory amino acids

The 22Na+ efflux stimulated by selected agonists of the 4 excitatory amino acid receptors, previously detected in the striatum, has been studied on 22Na+-preloaded slices prepared from 10 major areas of the rat brain. All brain areas were found to be sensitive, albeit to varying extents, to excitatory amino acids. The cerebellum was exceptional in its high sensitivity to kainate and quisqualate and in the absence of effect of N-methyl-D-aspartate. These results support the suggestion that excitatory amino acids interact with heteregenous receptors which differ from each other not only in their pharmacological properties but also in their regional distribution.     

Extremely low doses of oxytocin reduce pain sensitivity in men

The effect of extremely low doses of oxytocin (vapor) on the perception of pain (pricking of the finger) is studied on 48 healthy volunteers. Inhalation of oxytocin vapor from the standard solution in doses producing a sensation of smell lowers pain threshold by 56.5%. Inhalation of oxytocin vapor creating no sense of smell has a lower hypalgesic effect. The oxytocin-induced hypalgesia is consistent with reduction in the heart reactivity to pain. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 11, pp. 487–489, November, 1996     

Lower carcinogenicity of urethane for the lungs of athymic nude mice than for immunologically normal mice of the same litters

After two injections of urethane in a dose of 1 mg/g adenomas of the lungs developed in 2 of 10 nude mice and in 7 of 10 normal animals from the same litter. The mean number of adenomas per mouse was 0.2±0.13 and 1.2±0.36 respecitvely (p<0.05).Laboratory of Genetics of Cancer, Institute of Cytology and Genetics, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 11, pp. 574–576, November, 1978.     

Concentration of monoaminergic neurotransmitters and their major metabolites in the hippocamp and brain stem in mice after administration of adrenocorticotropic hormone (ACTH4–10)

ACTH_4–10 increases the concentration of monoaminergic neurotransmitters and the number of their metabolites in the brain of CBA and 101/HY mice. Different reactions to the peptide were revealed in both strains: the alterations were found either in brain stem (CBA strain) or in the hippocamp (101/HY strain). Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 350–352, September, 1998     

Role of brain stem in the mechanisms of individual resistance of rats to emotional stress

It is shown in rats that the structures of brain stem (medial and lateral nuclei) are involved in the mechanisms of individual resistance to emotional stress (immobilization and cutaneous electrostimulation). Bilateral destruction of brain stem structures reduces this resistance, which manifests itself as behavioral changes in the open field test (the behavior of rats resistant to stress resembles that of rats prone to it), increased adrenal hypertrophy, thymic involution, and high mortality under conditions of emotional stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 11, pp. 501–505, November, 1997     

Contribution of galaninergic structures of the brain to reaction to lipopolysaccharide

Relationship between blocking of galanine receptors in the brain and lipopolysaccharide-induced two-wave reaction and changes in neurotransmitter metabolism in the anterior and posterior hypothalamus, caused by provision of this reaction, are studied in rats. Intraventricular administration of the galanine receptor antagonist M-15 prevented the decrease in rectal temperature 3 h after intraperitoneal injection of lipopolysaccharide, thus rendering the pyrogenic reaction a prolonged single-wave pattern. Neurotransmitter changes, specifically, a decrease in the dopamine content in the anterior and increase in the posterior hypothalamus during reaction to endotoxin, are blocked by specific antagonist of the galanine receptor. These data indicate the participation of galaninergic mechanisms of the brain in central reactions to lipopolysaccharide. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 4, pp. 430–433, April, 1998     

Dissemination of human solid tumor cells in the bloodstream of immunodeficient mice

Seven human solid tumor cell lines transplanted into hereditarily immunodeficient mice (nude and beige/nude) were typed for tumor-associated surface antigens and glycoconjugates using fluorescent conjugates of 7 monoclonal antibodies, 5 lectins, and 2 ligands. With this set of 14 selected tumor markers, peripheral blood samples from mice bearing the respective tumors were examined by flow cytofluorimetry for the presence of tumor cells disseminated in their circulation. Tumor cells were detected in the blood of mice carrying a uterine tumor, indicating that the metastatic process can be followed intravitally in immunodeficient animals bearing human solid tumors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 615–618, December, 1995     

Effect of thymosin fractions on the development of toxic swelling edema of the brain

Rat experiments have shown that thymosin fractions V and VI elicit an antiedemic effect by normalizing predominantly the density of brain tissues, the effect being independent of the preparation dose. It is demonstrated that a high dose of fraction VII has a pronounced antiedemic effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, № 3, pp. 290–291, March, 1994 Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences a     

Genotypic,sex, and age differences in the clastogenic action of cyclophosphamide in mice

Interstrain genotypic, sex, and age differences in the clastogenic action of cyclophosphamide in various doses are established for C57B1/6, MRL/1, and BALB/c mice. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o , pp. 387–390, October, 1995     

Metastasizing of human melanoma on immunodeficient mice. Tumor cells in the circulation

The subline Bro of human melanoma xenograft with a high metastasizing activity is studied. The data obtained by flow fluorometry after staining with tumor-specific monoclonal antibodies indicate that free melanoma cells are present in the peripheral blood of animals; the largest number of these cells is found in mice with combined immunodeficiencies (beige/nude). Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 188–189, August, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences