Coronavirus infection induces H-2 antigen expression on oligodendrocytes and astrocytes

Infection of the central nervous system by mouse hepatitis virus strain A59, a murine neurotropic coronavirus, induces class I major histocompatibility complex antigens on mouse oligodendrocytes and astrocytes, cells that do not normally express these antigens on their surfaces. This induction, which occurs through soluble factors elaborated by infected glial cells, potentially allows immunocytes to interact with the glial cells and may play a critical role in the pathogenesis of virus-induced, immune-mediated demyelination in the central nervous system.     

Male-specific antigen: modification of potency by the H-2 locus in mice

Skin grafts from C57BL/10 (B10) male mice survive significantly longer than do B10.BR male skin grafts on (B10 x X B10.BR)F(1) females. This indicates that the H-2 locus influences the potency of the male-specific antigen in mice.     

Prevention of allogeneic bone marrow graft rejection by H-2 transgene in donor mice

Rejection of bone marrow grafts in irradiated mice is mediated by natural killer (NK) cells and is controlled by genes linked to the major histocompatibility complex (MHC). It has, however, not been possible to identify the genes or their products. An MHC class I (Dd) transgene introduced in C57BL donors prevented the rejection of their bone marrow by NK cells in irradiated allogeneic and F1 hybrid mice expressing the Dd gene. Conversely, H-2Dd transgenic C57BL recipients acquired the ability to reject bone marrow from C57BL donors but not from H-2Dd transgenic C57BL donors. These results provide formal evidence that NK cells are part of a system capable of rejecting cells because they lack normal genes of the host type, in contrast to T cells, which recognize cells that contain abnormal or novel sequences of non-host type.     

H-2 antigen on cell membranes: an explanation for the alteration of distribution by indirect labeling techniques

The distribution of H-2 isoantigens on the plasma membrane of lymphocytes and thymocytes was studied with ferritin-conjugated alloantibody. The spatial arrangement of the membrane components which possess H-2 isoantigens is markedly altered by the attachment of a second antibody, directed toward mouse gamma globulin or ferritin; the second anitibody appears to cause the aggregation of the sensitized H-2 antigens into discrete zones on the cell membrane. Other membrane antigens may be equally affected by indirect labeling techniques and, thus, topographic analysis of the antigenic structure should be done with antibody that is directly conjugated.     

H-2-linked resistance to mastocytoma in male mice: immune response to a histocompatibility antigen on the X chromosome

Male hybrids from a cross between female mice of strain C57BL/6Kh and males of strain DBA/2J lived longer after injection of P815 mastocytoma cells of DBA/2 origin than did their female siblings. Responses to the histocompatibility antigen on the X chromosome of the DBA/2 strain may be involved in resistance to the tumor. When the female parent was replaced with a C57BL/6Kh carrying one of several mutations in the H-2 region, this sex effect disappeared in some of the hybrid combinations. Thus, the H-2 complex appears to be involved in the regulation of the immune response to the X-linked histocompatibility antigen in this tumor model.     

Immune responses of inbred mice to repeated low doses of antigen: relationship to histocompatibility (H-2) type

Immunization of inbred strains of mice with repeated minute doses (0.1 to 1.0 microgram) of hapten-protein conjugates demonstrated wide differences in the magnitude of their antibody responses, which were related to the histocompatibility (H-2) type of the strains. Immunization with a single high dose (100 micrograms) of antigen failed to demonstrate these differences.     

产纤维素酶黑曲霉菌种的复壮

介绍了饲用酶制剂生产菌种黑曲霉纯化复壮的方法,并对复壮菌株、退化菌株、原始菌株的酶活力及长势进行了比较,结果表明经纯化复壮筛选出的7号菌株纤维素酶活力明显高于退化的菌株,且生长快、长势强,甚至优于原始菌株。     

Ethanol oxidation: effect on the redox state of brain in mouse

Administration of a single large dose of ethanol to mice results in increases, for concentrations in the brain, of ratios of lactate to pyruvate, of aglycerophosphate to dihydroxyacetone phosphate, of malate to oxaloacetate, and of glutamate to the product of alpha-ketoglutarate and ammonium ion. These changes are noticed as early as 5 minutes after the single dose is given. Ethanol administration for 30 days also produces these changes in metabolite concentrations in the brain. However, in contrast to the single alcohol dose, long-term alcohol administration results in a marked decrease in the concentration of adenosine triphosphate in brain and increases in those of adenosine diphosphate and adenosine monophosphate. Pyrazole, an inhibitor of alcohol dehydrogenase, prevents the effects of ethanol on the concentration of brain metabolites. These results may provide new insight into the biochemical and pharmacological effects of alcohol on brain metabolism and the importance of alcohol dehydrogenase activity in the brain.     

Streptonigrin: effect on the first meiotic metaphase of the mouse egg

Streptonigrin, an antibiotic and antitumor agent, alters the chromosomes of the mouse ovum during meiosis. Agglutination of bivalents or achromatic gaps and breaks occurred in the larger pairs both in vitro and in vivo. This newly detected cytogenetic effect suggests that such agents can gain access to developing mammalian ova and destroy the normal progress of meiosis.     

Australia antigen (hepatitis B antigen): a conformational antigen dependent on disulfide bonds

Reduction and alkylation of purified hepatitis-associated Australia antigen (hepatitis B antigen) resulted in a total loss of serologic activity. The reduced and alkylated protein formed a single band with a sedimentation coefficient of 31S on analytical ultracentrifugation, and no subunits were detected by Sephadex gel filtration. Although this preparation induced a delayed hypersensitivity response when injected into guinea pigs, it failed to stimulate humoral antibody formation. The data suggest that hepatitis B antigen is a conformational antigen critically dependent upon the disulfide bonds of the protein moiety.     

大黄素对小鼠变态反应性接触性皮炎的抑制作用

目的了解大黄素对小鼠变态反应性接触性皮炎(ACD)的抑制作用。方法30只8周龄昆明种小鼠制作成ACD模型,随机分为生理盐水组、地塞米松组和大黄素组(每组10例),分别用生理盐水、地塞米松和大黄素处理,比较各组小鼠实验部位的肿胀程度,采用ELISA法检测各组小鼠外周血肿瘤坏死因子-γ(IFN-γ)和白介素-4(IL-4)的水平。结果大黄素组小鼠右耳厚度及质量的增加均低于生理盐水组(P<0.05或0.01),地塞米松抑制小鼠右耳肿胀的效果最明显(P<0.01);大黄素组外周血IFN-γ及IL-4明显低于生理盐水组(P<0.01),而与地塞米松组比较,差异无统计学意义。结论大黄素对小鼠ACD具有抑制作用。     

程序化冷冻对小鼠胚胎发育的影响

取小鼠原核(220枚)、2～4细胞胚胎(227枚)、桑椹胚(127枚),将其分为3组,每一时期胚胎分成两半,一半取出后立即冷冻复苏并体外培养至囊胚,另一半体外培养至囊胚后冷冻复苏,子宫冲取囊胚(78枚)冷冻复苏为对照组;各组囊胚均移植至于宫,比较程序化冷冻对小鼠早期胚胎存活率的影响.结果表明:原核、2～4细胞胚胎、桑椹胚体外培养至囊胚后冷冻复苏率分别为56.4%、72.2%、81.6%,移植产仔率分别为38.1%、41.6%、56.8%,原核、2～4细胞组复苏率和产仔率极显著或显著低于对照组,桑椹胚组与对照组差异不显著,显示体外培养对早期胚胎冷冻存活有影响;原核、2～4细胞胚胎、桑椹胚冷冻后体外培养至囊胚,胚胎移植后产仔率分别为25.3%、28.2%、42.1%,与对应胚胎时期体外培养至囊胚冷冻复苏后移植产仔率相比,原核、2～4细胞组均存在显著差异,而桑椹胚组差异不显著,显示原核、2～4细胞的早期胚胎体外培养至囊胚后冷冻可提高冷冻存活率.     

GABA对小鼠离体十二指肠活动影响的研究

采用常规麦氏浴槽灌流法 ,研究了外源性γ -氨基丁酸 (GABA)及其类似物对离体小鼠十二指肠活动的影响 ,结果显示 :GABA明显抑制了离体小鼠十二指肠的自发活动 ,并明显存在剂量依赖性。GABAA 受体阻断剂印防己毒素和GABAB 受体激动剂巴氯芬均明显模拟此效应 ,增强阿托品对十二指肠的抑制作用 ,并逆转酚妥拉明对小鼠离体十二指肠的增强作用 ,所有的药物对肠段的活动频率均无影响。这些结果表明GABA对小鼠离体十二指肠的抑制作用是由GABAA 受体正性作用与GABAB 受体负性作用共同调节的 ,在生理状态下 ,以GABAB 受体的作用为主。GABAB 受体的这种作用可能是通过肠胆碱能系统介导来完成 ,也可能是独立的GABA能系统和 (或 )非胆碱能系统来完成 ,而与肾上腺素能系统无关     

双歧杆菌对正常小白鼠免疫调节及肠道菌群的影响

应用动物实验方法,研究婴儿双歧杆菌和长双歧杆菌对正常小白鼠免疫功能的调节作用以及对肠道菌群的影响。结果发现,两株菌对正常小白鼠体重、脾/体重和肾/体重比无显著性影响;对肝/体重比有增加趋势;能显著增加血液中IgA,IgG,C3,C4,IL-2,IL-6和IL-8的含量(P<0.05),婴儿双歧杆菌效果优于长双歧杆菌;婴儿双歧杆菌可极显著增加IgM的含量(P<0.01)。两株菌均可显著增加双歧杆菌(P<0.05)和乳杆菌的数量,显著降低肠杆菌的数量(P<0.05)。实验结果表明,两株菌对正常BALB/C小白鼠的免疫功能具有一定的正相调节作用,并具有良好调节肠道菌群能力,婴儿双歧杆菌效果优于长双歧杆菌。     

Genetic control of the antibody response: relationship between immune response and histocompatibility (H-2) type

The immune responses of inbred mice to a related series of three synthetic polypeptide antigens are genetically controlled traits which are closely correlated with the genotype for the major histocompatibility (H-2) locus. All strains of the same H-2 type exhibit the same pattern of immune response, independent of the remainder of a given strain's genetic background. There is marked antigen-specific polymorphism between strains of different H-2 types with respect to their patterns of response.     

Circadian activity rhythm of the deer mouse, Peromyscus: effect of deuterium oxide

Chemical modification of a vertebrate activity rhythm, the circadian (approximately 24-hour) rhythm of Peromyscus leucopus noveboracensis, has been demonstrated. Activity in a running wheel was used to measure the rhythms of mice kept individually in conditions of continuous darkness. Deuterium oxide was presented in the drinking water. The length of the periods of rhythm increased directly and linearly with the increase in concentration of deuterium oxide. There is no threshold for this effect, and the maximum concentration of deuterium oxide (30 percent) that was presented resulted in a 6 percent lengthening of the period of circadian rhythm. The mice reverted to rhythms similar in period length to control values after deuterium oxide was withdrawn from their drinking water.     

IL-6受体mRNA反义寡核苷酸抑制骨吸收的体外研究

目的：探讨IL-6RmRNA特异反义寡核苷酸(ASON)在体外对骨吸收的影响及意义。方法：采用器官培养法培养新生的小鼠颅盖骨,并分别用ASON、无义寡核苷酸(NSO)、IL-6或ASON与IL-6联合处理颅盖骨,未加药组为对照。培养一定时间后,测定培养上清液的钙含量,将实验组钙含量与对照组钙含量比值作骨吸收指数。结果：作用48h后,不同剂量的ASON均可轻度降低骨吸收指数,但无剂量依赖关系,ASON(5／μmol／L)对正常培养的颅盖骨的骨吸收的抑制率为8．6％;用IL-6培养颅盖骨使骨吸收指数呈剂量依赖关系升高,ASON(5．0／μmol／L)可能明显抑制由IL-6(40μg／L)引起的高骨吸收指数,其抑制率为58．0％;NSO对骨吸收指数无影响。ASON(5．0／μmol／L)分别作用12、24、48h的骨吸收指数则随时间延长而降低。结论：ASON阻断IL-6R表达后明显抑制IL-6刺激所致的新生小鼠颅盖骨骨吸收,而对正常培养的颅盖骨骨吸收抑制作用较弱。