EGFR expression and EGF stimulation of proliferation in human liver carcinoma cells

Epidermal growth factor receptor (EGFR) gene expression and growth stimulation of EGF on human hepatoma cells of cell lines BEL-7404 and SMMC-7721 were studied. 125I-EGF binding assay was used to measure the binding characteristics and the amounts of EGFR on these cells. The binding time course and the binding competition assay showed that the binding of 125I-EGF to 7404 cells was saturable and specific. Scatchard analysis of EGF binding curve indicated that 7404 and 7721 cells expressed approximately 1.1 x 10(5) and 0.7 x 10(5) EGFRs per cell with binding affinity (Kd) 2.1 nM and 1.8 nM respectively. Northern hybridization and immunoblotting analysis showed the EGFR gene expression products in 7404 and 7721 cells were 5.6 Kb mRNA and 170 Kilo-dalton glycoprotein. Anchorage-dependent growth of 7404 and 7721 cells was stimulated in the presence of nanogram quantities of EGF in medium containing 10% calf serum or 0.5% calf serum. The factors in serum appeared to act synergitically in stimulating of cell proliferation. EGF also stimulated the anchorage-independent growth of 7404 and 7721 cells in soft agar. The results suggest that EGFR is actively expressed in human hepatoma 7404 and 7721 cells and EGF may be one of the mitogens needed for the growth of hepatoma cells.     

蚕豆根端细胞核中微核仁的研究

以蚕豆(Vicia faba)根端分生组织细胞为材料研究了微核仁的超微结构和细胞化学特点。结果表明;微核仁是直径0.3—0.5μm 的卵圆形或球形结构。常规染色时,微核仁与集缩染色质的电子密度相仿,但两者之间在结构上没有任何联系。细胞化学研究指出,微核仁含有 RNA 和蛋白质,其结构成分主要是与核仁颗粒组分十分相似的 RNP 颗粒。报道了植物细胞核中微核仁发生于核仁的过程并对微核仁的本质和功能进行了讨论。     

新疆准噶尔盆地三个泉地区几种始新世哺乳类

本文记述了准噶尔盆地北缘三个泉地区依希白拉组中采到的踝节类、蹠行类、全齿类和恐角类化石。根据这些化石,依希白拉组的时代可能和北美中始新世勃力吉期相当。文内,通过文献分析,认为周明镇和胡长康(1956)记述的真恐角兽的前臼齿可能产自三个泉附近的依希白拉组。     

Fragment A of diphtheria toxin causes pH-dependent lesions in model membranes

Fragment A of diphtheria toxin has been shown to insert into lipid bilayers at low pH (Montecucco, C., Schiavo, G., and Tomasi, M. (1985) Biochem. J. 231, 123-128; Zhao, J.-M., and London, E. (1988) J. Biol. Chem. 263, 15369-15377). In this report, evidence is provided which demonstrates that fragment A, like diphtheria toxin, can also cause the release of a fluorescent dye (calcein) from vesicles under acidic conditions and that this release parallels fragment A insertion into the membrane. Although the permeability changes are not as large as those obtained with whole toxin (Jiang, G.-S., Solow, R., and Hu, V. W. (1989) J. Biol. Chem. 264, 13424-13429), molecular sieving experiments indicate that the lesion induced by fragment A increases in size with decreasing pH and reaches an upper limit of 30 A at pH 4.0. In addition to size differences, the lesion induced by fragment A releases calcein in a graded manner, whereas diphtheria toxin causes an all-or-none release. One possible interpretation of this result is that the fragment A lesion is transient in comparison to that induced by whole toxin. Although the molecular bases for the observed differences are not understood, these data suggest that fragment A interaction with the lipid bilayer may play a significant role in mediating its own translocation across membranes and that fragment B may aid this process by initiating, enlarging, and stabilizing the lesion formed.     

Dose-dependent metabolic response of mammary carcinoma to photodynamic therapy

The metabolic response of mammary carcinoma in the C3H mouse to photodynamic therapy (PDT) was measured using in vivo 31P nuclear magnetic resonance (31P-NMR) spectroscopy and pH microelectrodes. Twenty-four hours after administration of Photofrin II (12.5 mg/kg), the tumor was subjected to photoactivation using an argon dye laser. Optical treatment doses were 200, 400, and 600 J/cm2 and corresponded to the following tumor control doses: TCD10/30, TCD50/30, and TCD90/30, respectively. In vivo 31P-NMR spectra and pH micro-electrode measurements were obtained prior to treatment and at 4, 24, 48, and 72 h and 1 week post-treatment. The data revealed a significant (P less than 0.0002) alkalosis as indicated by the pH measured by NMR compared to pH measured by microelectrodes at all treatment levels and time points. Spectral differences between treatment groups were apparent as early as 4 h after treatment. The ratio of beta-nucleoside triphosphate to inorganic phosphate at 4 h after treatment was significantly (P less than 0.01) smaller for 600 J/cm2 treatment than for 200 J/cm2 treatment. At curative (600 J/cm2) levels, from 48 h on, no phosphate resonances were detected in the spectra. The pH measured by NMR transiently decreased from pretreatment levels after 200 and 400 J/cm2 treatment (P less than 0.002, P less than 0.009, respectively), while no change in pH from pretreatment values was found after 600 J/cm2 treatment. The data suggest that the early metabolic response of mammary carcinoma to PDT, as indicated by 31P-NMR spectroscopy, is dose dependent, and may be a sensitive indicator of biological outcome to treatment.     

小鼠LAK细胞对红系祖细胞及多向造血祖细胞增殖的影响

小鼠脾细胞经重组人白细胞介素-2(rhIL-2)激活后对YAC-1,LP-3和WEHI-164等肿瘤细胞均有很强的杀伤活性。在CFU-E和BFU-E培养体系中,不同浓度LAK细胞与BMC直接加入或预温育4h后再培养,均能加强CFU-E和BFU-E增殖。低浓度LAK细胞(LAK/BMC为0.5)与BMC直接加入或预温育后再加入CFU-mix培养体系中,均能增强CFU-mix增殖,而高浓度LAK细胞和BMC(LAK/BMC=8.0)直接加入培养体系则抑制CFU-mix增殖;若共温育后再培养则非常明显地抑制CFU-mix增殖,CFU-mix仅为对照的17.6％。小鼠LAK细胞对造血祖细胞体外增殖具有调节作用,这种调节可能包括分泌某些细胞因子以及细胞间直接相互作用两种方式。     

五种水蛭对不同P^H值的生物效应

本文论述了使用常规试验方法研究5种水蛭:宽身舌蛭(Glossiphonia lata)、八目石蛭(Erpobdella octoculata)、光润金线蛭(Whitmania laevis)、尖细金线蛭(Whitmania acranulata)和日本医蛭(Hirudo nipponia)对12个pH值的24—96小时急性生物效应。结果表明:稻田3个种(尖细金线蛭,光润金线蛭和日本医蛭)均较湖泊近岸2个种(八目石蛭和宽身舌蛭)对pH值的变化要敏感,其中尖细金线蛭最敏感(pH6.0—7.2),八目石蛭的忍耐限度最宽(pH4.0—10.5);当pH值在9.5时,稻田3种水蛭的死亡率在40％以上,其中日本医蛭高达70％;当pH值在3.0时,湖泊近岸2种在24小时内全部死亡,日本医蛭仅死亡10％。日本医蛭是华中农村地区一种主要吸血蛭类,生石灰是一种从稻田消灭蛭类的有效手段,然而水的pH值必须不低于8.6。     

健康青少年口腔正常菌群的初步研究

本文采用非选择性培养基对22名健康青少年的唾液、沟裂菌斑、龈上菌斑及龈下菌斑中的需氧菌、兼性厌氧菌及专性厌氧菌进行了分离培养,并计算其在不同标本中占可培养菌的百分比及检出率。结果共分离到包括18个菌属的35种细菌。其中,链球菌、放线菌、奈瑟氏球菌、二氧化碳噬纤维菌、类杆菌、梭杆菌,奴卡氏菌及棒状杆菌在口腔4个部位的检出率及所占比例均较高,是健康青少年口腔中的优势菌群.通过比较还发现,其中一些菌在口腔4个部位的分布存在一定差异.本文还采用刚果红负性染色涂片法,镜下观察龈上、龈下菌斑中的螺旋体,并计算其相对比例.结果龈下菌斑中螺旋体的相对比例明显高于龈上菌斑.     

冬虫夏草多糖的分子结构与免疫活性

 冬虫夏草多糖(在本文中名为CS-81002)是由冬虫夏草菌Cordyceps sinensis(Berk)Sacc在人工发酵条件下产生的胞外多糖。用凝胶过滤法测出CS-81002的分子量Mr=43kD。CS-81002的单糖组成为Man:Gal:Glc=10.3:3.6:1。甲基化分析和部份酸水解结果表明,CS-81002是多分支的杂多糖,由→6)-Manp-(1→形成主链,大约每10个主链Man残基中,有6个在C3位上被取代(即形成→3,6)-Manp-(1→分支),有4个在位C2上被取代(即形成→2,6-Manp-(1→分支),从而形成侧链。主链中还有少许未被取代的Man残基。侧链则由→3-)-Galf-(1→,→4)-Glcf-(1→,→4)-Manp-(1→和→2)-Manp-(1→组成。位于非还原末端的,则三种单糖残基都有。CS-81002在5mg/kg体重×12剂量条件下,对正常的昆明小鼠腹腔巨噬细胞吞噬功能有显著促进作用。在同样剂量条件下,对正常LACA小鼠脾脏溶血斑形成细胞(PFC)对绵羊红细胞的溶血作用无显著影响。不同程度的部份酸水解可使CS-81002的分子量下降,分支减少,并且对巨噬细胞吞噬功能的促进作用亦有下降趋势。在所得到的各个部份酸水解级分(分子量分别为41000,40000,32000,16000和12000)中,分子量为12000的级分对巨噬细胞吞噬功能无促进作用。     

Contractile properties of bronchial smooth muscle with and without cartilage

The majority of in vitro studies on airway smooth muscle have used the trachealis (TSM) as a convenient substitute for muscle from airways that constitute the flow-limiting segment. The latter are technically difficult to work with. However, because the site of maximum resistance to airflow is at the third to seventh generations of the bronchial tree, the trachealis preparation is of limited value. Length-tension and force-velocity properties were therefore studied at optimal length (lo) of canine bronchial smooth muscle (BSM) from which cartilage had been carefully removed. Normalized maximum isometric tension or stress (Po x 10(4) N/m2) for BSM was 7.1 +/- 0.19 (SE), which was similar to that of BSM with cartilage (BSM+C, 6.8 +/- 0.21) but lower than for TSM (18.2 +/- 0.81). At length greater than lo, the BSM+C was stiffer than the BSM. The values of maximum shortening capacity (delta Lmax), obtained directly from isotonic shortening at a load equal to the resting tension at lo, were 0.76 lo +/- 0.03, 0.41 lo +/- 0.02, and 0.24 +/- 0.02 lo for TSM, BSM, and BSM+C, respectively. The BSM and BSM+C delta Lmaxs were different (P less than 0.05). Maximal shortening velocities (Vo) for BSM, elicited at 2, 4, and 8 s by quick release in the course of an isometric contraction were significantly higher than for the BSM+C. Vos showed gradual decreases in all three groups in the later phase of contraction, suggesting the operation of latch bridges.(ABSTRACT TRUNCATED AT 250 WORDS)