板蓝根磷脂对内毒素血症小鼠巨噬细胞膜脂流动性的影响

目的　以小鼠内毒素血症为模型 ,观察板蓝根磷脂对内毒素血症小鼠巨噬细胞膜脂流动性的保护作用。方法　小鼠分为板蓝根氯仿提取物预处理组、磷脂脂质体预处理组、板蓝根磷脂脂质体预处理组和内毒素血症对照组。各组按照上述次序分别给予腹腔注射 5ml/kg相应药物 ,预处理 18h后腹腔注射内毒素 6mg/kg。 6h后处死小鼠 ,观察细胞膜脂流动性的变化。结果　板蓝根氯仿提取物对内毒素血症小鼠巨噬细胞膜脂流动性的保护作用没有达到具有统计学意义的程度 (P >0 .0 5 ) ,磷脂脂质体对膜脂流动性具有保护作用 (P <0 .0 5 ) ,但两者之间并没有统计学上的差别 (P >0 .0 5 ) ;板蓝根磷脂对内毒素血症小鼠细胞膜脂流动性具有明显的保护作用 (P <0 .0 1) ,优于单独使用板蓝根氯仿提取物 (P <0 .0 5 )或磷脂脂质体 (P =0 .0 5 )。结论　板蓝根磷脂脂质体对内毒素血症小鼠巨噬细胞膜脂流动性的保护作用优于单独使用板蓝根氯仿提取物或磷脂脂质体     

Leukaemia Inhibitory Factor or Related Factors Promote the Differentiation of Neuronal and Astrocytic Precursors within the Developing Murine Spinal Cord

Previously we have shown that leukaemia inhibitory factor (LIF) potentiates the development of murine spinal cord neurons in vitro , suggesting that it, or related factors, may play an important regulatory role in neuronal development. We have further investigated this role and show here that the generation of neurons in cultures of embryonic day 10 spinal cord cells is inhibited by antibodies to the β subunit of the LIF receptor. Since there are more undifferentiated precursors in antibody-treated cultures than in control and LIF-treated cultures, it is concluded that the primary action of LIF, or related molecules, is to promote neuronal differentiation, not precursor survival. In addition, the failure of LIF to support neuronal survival in the period immediately following differentiation suggests that the increased numbers of neurons generated with LIF are not attributable to its neurotrophic action. By selecting neuronal precursors on the basis of their inability to express class I major histocompatibility complex molecules, it was shown that LIF acted directly upon these cells and not via an intermediary cell. LIF also appears to be involved in regulating the differentiation of astrocytes, since it increases the number of glial fibrillary protein (GFAP)-positive cells present in the cultures and since the spontaneous production of GFAP-positive cells is blocked by antibodies to the LIF β receptor. These findings suggest that LIF or related factors promote the differentiation of neural precursors in the spinal cord, but that they are not involved in preferentially promoting precursors down a specific differentiation pathway.     

A p65/p95 Neural Surface Receptor is Expressed at the S-G2 Phase of the Cell Cycle and Defines Distinct Populations

A surface receptor complex of M _r˜65 000 (p65) and ˜95 000 (p95) is expressed in cells of the central nervous system of mice. This receptor is recognized by monoclonal antibody 87.92.6 or by reovirus type 3 haemagglutinin as unnatural ligands. The p65/p95 receptor is expressed mostly in neural embryonic precursors undergoing proliferation, especially those in the S-G₂ phase of the cell cycle. Receptor expression decreases progressively throughout embryogenesis to low but detectable levels in the adult brain. Biochemical characterization revealed that the neural p65/p95 receptor complex is indistinguishable from the p65/p95 receptor expressed in T cells, where receptor ligation leads to a mitogenic block. In neural and lymphoid tissues the p65/p95 receptor (or an associated protein) possesses a tyrosine kinase enzymatic activity. Receptor ligation in neural cells resulted in the rapid tyrosine phosphorylation of cellular proteins which are different from substrates phosphorylated in T cells. Differential substrate coupling to the receptor may account for differences in signal transduction and biology between neural cells and T cells. Further study of this receptor complex may help define important features of neural proliferation, differentiation and survival.     

MPTP对鼠肝脂质过氧化作用的影响

本文报道给C57小鼠腹腔注射不同剂量1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)后,发现组3(MPTP35 mg/kg,每天一次,共7天)鼠肝匀浆、线粒体和微粒体的膜丙二醛含量明显增加,与对照组相比分别增加70.5%,67%和51.4%(P<0.01),而组1(MPTP 35mg/kg,每4小时一次,共3次)和组2(MPTP35mg/kg,每天一次,共4天)鼠肝丙二醛含量与对照组相近。结果表明MPTP有明显地促进鼠肝脂质过氧化的作用,并与其剂量有关。     

Synergistic actions of the vitamin D analogue MC 1288 and 15-deoxyspergualin in xenotransplantation

Abstract: The vitamin D analogue MC 1288 (20-epi-1α,25-dihydroxycholecalciferol) effectively postpones rejection of cardiac, intestinal, skin, and aortic allografts. MC 1288 binds to the vitamin D receptor and is thus assumed to exert its immunosuppressive effects via the same mechanisms as 1α,25-dihydroxycholecalciferol, the active form of vitamin D. 1α,25-Dihydroxycholecalciferol has been demonstrated to inhibit the production of various cytokines (interleukin-2, interferon-γ, granulocyte macrophage colony-stimulating factor, and interleukin-12) and to prevent B lymphocyte secretion of immunoglobulins. In the present study MC 1288 was evaluated for its ability to prevent rejection of mouse-to-rat cardiac xenografts, alone and in combination with 15-deoxyspergualin (DSG). Combined treatment with MC 1288 (given days -1 to 9) and DSG (given day -1 and onward) postponed rejection from day 3.0 (untreated recipients) until day 19.5. In rats treated with MC 1288 or DSG as monotherapy, rejection occurred after 3.0 and 7.5 days, respectively. Functioning grafts, obtained on day 9 from recipients treated with MC 1288 and DSG in combination, displayed an almost normal morphology without any obvious deposition of immunoglobulins in the vessels of the grafts and with just a few infiltrating cells. Thus, we have demonstrated synergistic actions of MC 1288 and DSG in delaying rejection of xenografts. Analysis of cellular infiltration, immunoglobulin deposition and graft survival times in the various treatment groups indicate a combined inhibitory effect of these two drugs on the level of macrophage effector function, direct or indirect via T lymphocytes, as well as on antibody production.     

益气补肾汤对小鼠免疫功能的影响

目的 :研究益气补肾汤对小鼠免疫功能的影响。方法 :用药理实验的方法 ,将小鼠制成免疫抑制模型 ,灌服益气补肾汤 ,观察和测定小鼠巨噬细胞吞噬功能 ,胸腺、脾指数 ,迟发性超敏反应及溶血素抗体水平。结果 :灌服益气补肾汤的小鼠与灌服蒸馏水的免疫抑制模型小鼠相比 ,巨噬细胞吞噬能力增强 (P <0 .0 5 ) ,胸腺指数升高(P <0 .0 5 ) ,迟发性超敏反应增强 (P <0 .0 5 ) ,且血清溶血素抗体升高 ,脾指数 2组间差异无统计学意义。结论 :益气补肾汤可增强机体免疫功能     

Biochemical Modulation of 5-Fluorouracil with Murine Interferon-α/β Against Murine Renal Cell Carcinoma

Department of Urology, School of Medicine, Keio University, Tokyo, Japan
Background Conventional therapy for renal cell carcinoma using interferon (IFN) has shown limited antitumor action. The purpose of our study was to investigate synergistic antitumor effects of IFN and 5-fluorouracil (5-FU), and to elucidate the mechanisms of interaction between the 2 agents in mice.
Methods Antitumor effects and biochemical modulation of murine IFN-α/β and 5-FU were determined against the murine renal cell carcinoma cell line, Renca, in vivo. The activity of thymidylate synthetase and thymidine kinase was measured using cytosolic extracts of the tumors.
Results Combination treatment with IFN-α/β and 5-FU produced a significant enhancement of growth inhibition against Renca tumor. Treatment with 5-FU resulted in a 2.7-fold increase in the total amount of thymidylate synthetase and an 11.6-fold increase in the thymidylate synthetase inhibition rate, while the administration of IFN-α/β did not significantly reduce the 5-FU-induced increase in thymidylate synthetase. The administration of IFN-α/β decreased thymidine kinase activity to 65.5% maximally, compared with that in the control mice or the mice treated with 5-FU.
Conclusions The reduction of thymidine kinase caused by treating the mice with IFN-α/β changes the utilization of exogenous thymidine for DNA synthesis, and may represent the mechanism of the additive antitumor effect of the 2 agents, through the suppression of the salvage pathway for deoxythymidine monophosphate induction.     

Lack of Allelic Preference in Amplification and Loss of the c-myc Oncogene in Methylcholanthrene-induced Mouse Sarcomas

Sarcomas were induced in Fl mice between C57BL/6N and C3H/He strains by subcutaneous injection of methylcholanthrene. The c-myc oncogene was found to be amplified in 16 cases among 43 sarcomas of C57BL/6N × C3H/He mice and 1 case among 5 sarcomas of the reciprocal cross. The origin of the amplified allele was determined by the polymerase chain reaction single strand conformation polymorphism analysis. Among the 17 sarcomas, only one had both of the alleles amplified. The rest of the tumors carried the amplified c-myc allele coming either from C57BL/6N (9 cases) or from C3H/He (8 cases). These results indicate that the c-myc allele is amplified randomly in methylcholanthrene-induced mouse sarcomas irrespective of its origin, such as paternal or maternal allele and C57BL/6N or C3H/He allele. In addition to these changes, the unamplified c-myc oncogene was found to be lost in 12 cases out of the 17 sarcomas with the amplification.     

Passively transferable protection against Schistosoma japonicum induced in the mouse by multiple vaccination with attenuated larvae: the development of immunity, antibody isotype responses and antigen recognition

Vaccination of mice with attenuated S. japonicum cercariae induces protection against secondary infection which can be transferred to naive mice with serum (VMS). The presence of antibody does not per se impart protection as serum from mice carrying non-attenuated infections (CIS), contains high levels of specific antibody, but confers no protection. Here we describe the increased protection transferred (20 to 68%) with increased number of vaccinations (one to five) given to the donors, and its decline with time after the final vaccination. We also describe the development of IgM, IgA, IgE, total IgG and IgG subclass responses in VMS, giving different levels of protection and CIS, directed against sodium periodate-sensitive and -resistant epitopes in ‘skin-stage’, ‘lung-stage’and ‘liver-stage’schistosomula, adult worms and eggs. In addition, antibody affinity maturation, development of S. japonicum species-specific responses, and vaccination-specific responses were examined. No response developed in parallel with serum-mediated immunity, suggesting immunity may be due to responses against individual antigens. Preliminary examination of antigens recognized in Western blot showed that two schistosomal membrane antigens, of 13 and 40 kDa, were recognized by VMS from mice vaccinated five times (68% protection), but not by twice vaccinated VMS (27% protection). Neither antigen was recognized by non-protective CIS.     

Concentration-dependent metabolism of diazepam in mouse liver

Previous mouse liver studies with diazepam (DZ),N-desmethyldiazepam (NZ), and temazepam (TZ) confirmed that under first-order conditions, DZ formed NZ and TZ in parallel. Oxazepam (OZ) was generatedvia NZ and not TZ despite that preformed NZ and TZ were both capable of forming OZ. In the present studies, the concentration-dependent sequential metabolism of DZ was studied in perfused mouse livers and microsomes, with the aim of distinguishing the relative importance of NZ and TZ as precusors of OZ. In microsomal studies, theK _ms andV _maxs, corrected for binding to microsomal proteins, were 34 μM and 3.6 nmole/min per mg and 239 μM and 18 nmole/min per mg, respectively, forN-demthylation andC ₃-hydroxylation of DZ. TheK _ms andV _maxs forN-demethylation andC ₃-hydroxylation of TZ and NZ, respectively, to form OZ, were 58 μM and 2.5 nmole/min per mg and 311 μM and 2 nmole/min per mg, respectively. The constants suggest that at low DZ concentrations, NZ formation predominates and is a major source of OZ, whereas at higher DZ concentrations, TZ is the important source of OZ. In livers perfused with DZ at input concentrations of 13 to 35 μM, the extraction ratio of DZ (E{DZ}) decreased from 0.83 to 0.60. NZ was the major metabolite formed although its appearance was less than proportionate with increasing DZ input concentration. By contrast, the formation of TZ increased disporportionately with increasing DZ concentration, whereas that for OZ decreased and paralleled the behavior of NZ. Computer simulations based on a tubular flow model and thein vitro enzymatic parameters provided a poorin vitro-organ correlation. TheE{DZ}, appearance rates of the metabolites, and the extraction ratio of formed NZ (E{NZ, DZ}) were poorly predicted; TZ was incorrectly identified as the major precursor of OZ. Simulations with optimized parameters imporved the correlations and identified NZ as the major contributor of OZ. Saturation of DZN-demethylation at higher DZ concentrations increased the role of TZ in the formation of OZ. The poor aqueous solubility (limiting the concentration range of substrates usedin vitro), avid tissue binding and the coupling of enzymatic reactions in liver, favoring sequential metabolism, are possible explanations for the poorin vitro-organ correlation. This work emphasizes the complexity of the hepatic intracellular milieu for drug metabolism and the need for additional modeling efforts to adequately describe metabolite kinetics. This work was supported by the Medical Research Council of Canada (MA-9104).