Some biological characteristics of hybridomas and parental myelomas cultivated in serum-free medium for long-term period

It has been developed in this laboratory that a serum-free medium, designated asDMI,is adaptive for long-term culture,freezing and resurgence in liquid nitrogen,and cloningof hybridoma and parental myelomas as well as for cell fusions.In this report,it is describedthat the myeloma cells grown in DMI for more than 3 months maintained their biological charac-teristics such as induction of aseites and subcutaneous somatic tumor in BALB/c mice and toler-ance toward 8-azaguanine,ete..However,the ability of the tumor cells to attach to glass wallwas decreased.The selecting assay of these cells in HAT medium(medium containing hypoxan-thine,aminopterin and thymidine)showed that the death time in DMI was similar to that in theconventional 15％ newborn calf serum-supplemented medium(RPS15).The hybridoma cellsadapted in DMI secrete monoclonal antibodies in quantities comparable to those produced inRPS15.

Cholesterol requirement for growth of rodent parental myeloma cells in serum-free medium

Cholesterol,a major lipid component of plasma membrane,is thoughtto have profound effects on the structure and function of cells.Mostanimal tis-sues are capable of synthesizing cholesterol de novo from acetate;however,thereare relatively few mammalian cells in vitro expressing an absolute requirement foran exogenous source of cholesterol.In this paper,it was shown that IR983F(983)rat myeloma cells and P3X63-AgS-U1(P3U1)and P3X63-Ag8.653(653)mousemy eloma cells which had been cultivated in serum-free medium for more than 6months required cholesterol in vitro for growth in serum-free medium.Optimalgrowth of P3U1,653 and 983 occurred in cholesterol concentration of 5,10 and15μg/ml,respectively.Moreover,it was demonstrated that the cholesterol couldbe replaced by human low density lipoprotein in a concentration of 10μg/ml butnot by mevalonic acid lactone.In contrast to the parental myeloma cells,hybridoma cells derived from the mouse myeloma cells which had been cultivatedin serum-free medium for more than 6 months did not require cholesterol.

Novel sericin-based hepatocyte serum-free medium and sericin's effect on hepatocyte transcriptome

AIM To develop a novel hepatocyte serum-free medium based on sericin,and to explore the effect of sericin on the hepatocyte transcriptome.METHODS A controlled trial comparing novel serum-free medium and other media: C3 A cells were cultured in our novel serum-free medium,Hepato ZYME,complete medium(DMEM/F12 with 100 m L/L FBS),and DMEM/F12,andthen cell attachment,proliferation,and function as well as the biocompatibility of the media were assessed.A comparative study of serum-free media with or without 2 mg/m L sericin: the effect of sericin on C3 A growth was assessed by cell viability and proliferation,the effect of sericin on C3 A cell cycle distribution was determined by flow cytometry,and the effect of sericin on the C3 A transcriptome was assessed by gene-chip array and RT-q PCR.RESULTS More C3 A cells attached to the plate containing our serum-free medium than to those containing Hepato ZYME and DMEM/F12 at 24 h post-seeding.Both the viability and proliferation rate of C3 A cells in sericin-based serum-free medium were superior to those of cells in Hepato ZYME and DMEM/F12(P < 0.001).The content of albumin and urea in our serum-free medium was significantly higher than that in Hepato ZYME and DMEM/F12 throughout the whole culture period(P < 0.001) and was similar to that in complete medium at day 3,4,and 5.In part 2,cell viability and proliferation were greater in the presence of 2 mg/m L sericin(P < 0.001),as was the proportion of cells in S phase(16.21% ± 0.98% vs 12.61% ± 0.90%,P < 0.01).Gene-chip array analysis indicated that the expression of CCR6,EGFR,and FOS were up-regulated by 2 mg/m L sericin,and RT-q PCR revealed that the expression of CCR6,EGFR,FOS,AKT1,JNK1,NFk B1,MMP-9,MEK2,ERK1/2 and MYC was upregulated by 2 mg/m L sericin(P < 0.05).CONCLUSION We developed a novel hepatocyte serum-free medium.Sericin probably enhances cell attachment through the CCR6-Akt-JNK-NF-κB pathway and promotes cell proliferation through CCR6-mediated activation of the ERK1/2-MAPK pathway.

A PRIMARY OBSERVATION OF TPA EFFECT ON SSV-NIH3T3 CELLS IN SERUM-FREE MEDIUM

The effect of TPA, a potent tumor promoter, on SSV-NIH3T3 cells in serum-free medium was investigated. TPA stimulated DNA synthesis of SSV-NIH3T3 cells on the third day of culture in SFM. In SDS-PAGF of medium conditioned by TPA-treated SSV-NIH3T3 cells (in SFM+TPA), the amounts of four proteins of 31.0 Kd, 28.5 Kd, 25.5 Kd and 13.5 Kd strikingly increased over that of non-TPA-treated counterpart (in SFM). The PDGF-like activity was also detected in CM of SFM+TPA. When insulin and EGF were drown off the SFM+TPA (SFM-Ins-EGF+TPA), TPA lost its ability to stimulate DNA synthesis of SSV-NIH3T3 cells on the third day and SDS-PAGE of the conditioned medium showed that the amounts of the four proteins noted above grately reduced. However, cells in SFM-Ins-EGF+TPA were in almost the same growth condition as cells in complete SFM+TPA on the third day of culture. Results were discussed in the paper.

陶瓷滤管基体粉尘沉积状况SEM分析

将树脂包埋、固化技术成功应用在陶瓷滤管基体的SEM分析上,能够在不破坏基体和粉尘沉积结构的情况下对滤材内的孔隙率、孔隙直径、颗粒直径、沉积量等微观参数进行测量和分析。使用压汞仪和X-射线衍射仪(XRD)对测量和计算结果进行了验证和分析,证明实验方法可靠,测量结果准确。SEM测量结果表明尽管陶瓷滤管基体由相同尺寸的陶瓷颗粒制成,由于颗粒本身的不规则和堆积结构的随机性,基体内孔隙差别很大,这会导致局部的速度场和浓度场分布不均,引起粉尘沉积和阻力增加。随着脉冲反吹循环次数的增加,粉尘沉积有加剧并向内部延伸的趋势。

基于SEM的科技型中小企业技术创新能力评价

论文以科技型中小企业为研究对象,首先,根据科技型中小企业的特性,构建以创新投入能力、创新产出能力、外部资源获取能力为一级指标的技术创新能力评价指标体系,并通过问卷调查确定14个观测变量;其次,构建基于SEM的技术创新能力评价模型,并运用AMOS软件进行验证性因子分析和路径分析,通过归一化系数得到指标权重;最后,对科技型中小企业技术创新能力各指标进行测量,在此基础上对湖南省科技型中小企业的创新能力进行综合评价,得出该类企业当前整体技术创新能力一般。研究结论对提高我国中小企业创新能力具有一定的指导价值和决策参考。论文研究为我国中小企业的创新能力的评价提供了一种新思路、新方法。

Investigate the Corrosion Inhibition of Mild Steel in Sulfuric Acid Solution by Thiosemicarbazide

Corrosion inhibition of mild steel in 0.5 mol/L H2SO4 was investigated in the absence and presence of different concentrations of thiosemicarbazide. The inhibition efficiency of thiosemicarbazide was studied by electrochemical impedance methods, potentiodynamic polarization and scanning electron microscopy at different inhibitor concentrations. Inhibition efficiency, corrosion rate and surface coverage were evaluated at different concentrations of thiosemicarbazide. Electrochemical impedance plots indicated that the presence of the inhibitors increased the charge transfer resistance of the corrosion process, increasing the inhibition efficiency. Polarization curves showed that this compound acted as mixed type inhibitor. The results of the investigation showed that this compound had good inhibiting properties for mild steel corrosion in 0.5 M sulfuric acid. The adsorption isotherm studies showed that Thiosemicarbazide adsorbed chemisorbed and formed a stable surface complex on the mild steel surface. And Langmuir obeyed the adsorption isotherm. Scanning electron microscopy analysis shows that, the surface morphology of the polished mild steel in the presence of thiosemicarbazide as inhibitor is smoother surface as compared with polished mild steel specimen in the absence of inhibitor.

STUDY ON REPRODUCTIVE ENDOCRINOLOGY OF HUMAN PLACENTA--CULTURE OF HIGHLY PURIFIED CYTOTROPHOBLAST CELL IN SERUM-FREE HORMONE SUPPLEMENTED MEDIUM

A new method of long-term culture of cytotrophoblast cells in serum-free medium has been developed. Cytotrophoblast cells were isolated with cold trypsin and purified by unit gravity sedimentation through BSA density gradients. The cells were cultured in the FD medium with supplement of EGF, insulin, transferrin and sodium selenite. They could survive over three weeks. The results showed that both EGF and insulin stimulated hCG and progesterone secretion and that sodium selenite elevated hCG output but not progesterone secretion. Transferrin produced synergistic effect with EGF and insulin on hCG and progesterone secretion but it was ineffective when used alone. This study demonstrates that the four growth factors mentioned above are essential for the survival of cytotrophoblast cells in vitro. It is therefore suggested that EGF, insulin and selenium may possibly be involved in the regulation of hCG and progesterone secretion in the human placenta.

中小企业融资现状、影响因素及对策研究

通过实地考察和问卷调研的方式对获取的数据资料进行实证分析,剖析制约中小企业融资的因素,从而有针对性地从政府、金融和企业不同角度提出解决融资困境的措施和建议,提出了完善政府支持体系建设,包括建立促进中小企业发展的专项基金,构建中小企业融资的专门机构,完善政府服务支持体系;建立多元融资体系,包括降低银行融资成本与条件,合理发展非传统融资渠道,完善融资供给体系,促进数字金融的发展;提升中小企业自身融资能力,包括提升中小企业盈利能力,加强企业信用和个人信用意识,规范中小企业信息披露。

Enrichment of breast cancer stem cells using a keratinocyte serum-free medium

Background Keratinoyte serum-free medium （K-SFM） is a defined medium used to support the growth of primary keratinocytes and embryonic stem cell. The aim of this research was to optimize enrichment of breast cancer stem cells （CSCs） using K-SFM. Methods＇ A K-SFM was used to enrich CSCs from two breast cancer cell lines and a primary culture of breast cancer. RPMI-1640 supplemented with 10% fetal calf serum （FCS） was used as a control. CSCs were identified with flow cytometry using CD44＋/CD24-as molecular markers. The expression of a variety of CSC markers （Oct-4, ABCG2, Nanog, N-cadherin, and E-cadherin） was analyzed with real-time PCR. Results Much higher percentage of CSCs was achieved with K-SFM： 17.3% for MCF-7 cells, 17.4% for SKBR-3, and 20.0% for primary breast cancer culture. Less than 1% CSC was achieved using RPMI-1640 supplemented with 10% FCS. In comparison to the CSCs obtained with RPMI-1640, CSCs in the K-SFM expressed higher levels of Oct-4, ABCG2, Nanog and N-cadherin, and lower level of E-cadherin. Conclusion K-SFM is an optimal culture medium to maintain and to enrich breast CSCs.

Application of Serum-Free Culture Medium for Preparation of A-NK Cells

To compare the differences between proliferation and cytotoxicity of adherent natural killer （A-NK） cells cultured with serum-free medium AIMV and standard serum-containing medium in vitro, and also observe the assisting effect of IL-12 on the activation and the morphology character of IL-2-treated A-NK cells, cellular proliferation was evaluated by MTT method in vitro. The morphology of the target cells killed by A-NK cells was observed through electroscope. All of the A-NK cells cultured in serum-free medium AIMV could rapidly proliferate and keep high cytotoxicity compared with that in standard serum-containing medium. A-NK cells activated by both moderate-dose IL-2 and IL-12 were superior to the high-dose IL-2-treated A-NK cells. These data indicated that serum-free medium AIMV could replace standard serum-containing medium for culturing A-NK cells, and moderate-dose IL-2 and IL-12 could reduce side effects caused by high-dose IL-2. The study provided a new experimental basis for experimental and clinical preparation of A-NK cells. Cellular ＆ Molecular Immunology.

中小企业安全管理员胜任力影响因素分析

为研究中小企业(SMEs)安全管理员胜任力的影响因素,采用问卷法对201名长三角地区中小企业的安全管理员开展调查。通过结构方程模型(SEM)分析岗位特征、工作氛围、个人特质的影响作用,探究知识技能的中介效应。结果表明:工作氛围、个人特质对中小企业安全管理员胜任能力有正向影响,其中工作氛围的影响更为显著(其路径系数为0.43);个人特质直接正向影响安全管理员胜任力,工作氛围对安全管理员胜任力有间接正向影响。

企业文化、人力资源与中小型科技企业成长关系研究

企业文化、人力资源及其相互关系是影响中小型科技企业绩效的重要因素。为此,以中小型科技企业为样本,运用多元统计分析方法和结构方程模型,对企业文化、人力资源对中小型科技企业成长的影响进行实证研究。检验结果表明,企业文化对科技与管理人才结构、人才流动和能力培训等有积极作用。同时,人力资源对中小型科技企业成长潜力、生存状态等有显著的正效应。结构关系检验结果进一步说明,企业文化与人力资源之间存在显著的正相关关系,并对中小型科技企业绩效产生影响。

不同硫含量石油焦中低温煅烧性能及脱硫机理研究

在实验室煅烧炉内对三种不同品种石油焦进行了700~1100℃阶段热处理,并对煅烧后的石油焦真密度、粉末电阻率、Lc值、气孔率等进行了检测分析,同时将煅烧后的石油焦颗粒进行了扫描电镜分析。通过分析研究发现,随着煅烧温度的增加,低硫、中硫、高硫石油焦TG和DTG曲线、煅烧后的性能、脱硫率、碳晶格的生长、气孔率等区别明显,这可为生产使用这三种类型硫含量的石油焦提供试验依据。

家兔甲状腺内淋巴管铸型扫描电镜观察

用自行研制的水溶性淋巴管铸型剂（合成树脂三元共聚体的乳状溶液，共聚体含量占５０％），作器官实质注射，得到完整的兔甲状腺淋巴管铸型。甲状腺内淋巴管比相应的血管粗大，形状不规则。最显著的特点是许多淋巴管呈囊状膨大，且多位于小叶之间，称淋巴小囊，其大小与形状变化较大。这些淋巴小囊与其他淋巴管相互连接，构成三维的淋巴管系统，淋巴管铸型中呈盲端的淋巴管及一些淋巴小囊属于起始淋巴管（ｉｎｉｔｉａｌｌｙｍｐｈａｔｉｃｓ）。

中小企业安全投入行为决策研究

为探究影响中小企业(SME)安全投入行为决策的因素,进而促进投入行为,改善其安全水平,基于计划行为理论(TPB),增加企业过去行为变量,构建决策模型。以江苏某市部分中小企业为样本,运用结构方程模型(SEM),研究安全投入行为决策影响因素及其影响程度。实证研究表明:企业安全投入态度、主观规范、过去安全投入行为等因素影响其投入意向,并通过意向变量间接影响企业实际安全投入行为。安全投入态度对安全投入行为影响最大,企业过去行为对其安全投入行为有延续影响。

中小型科技企业成长的外部环境因素模型研究

外部环境是中小型科技企业生存与成长的重要基础。首先,在运用生态学理论界定中小型科技企业外部环境内涵的基础上识别影响其成长的外部环境因子。然后,分析外部环境因子对其成长影响的作用机理,并以山东地区的中小型科技企业为样本,设计测量指标体系,运用结构方程方法构建中小型科技企业成长外部环境因素模型,从而为优化中小型科技企业成长的外部环境提供有益的启示。

产业集群内中小企业技术创新与政府行为

技术创新是企业保持持续竞争力的关键因素。产业集群内的中小企业与孤立于集群外的中小企业相比,由于集群效应获得提高自身创新能力和拓宽创新途径的机会,但仍处于技术创新滞后的状况。基于此,本文分析了集群内中小企业技术创新的障碍,并通过政府在促进集群内中小企业技术创新活动中行为定位的探讨,提出了政府应从财税激励、政府采购、共享机制、融资支持、中介服务机构等方面对中小企业技术创新活动进行有效支持。

区域中小企业创新系统竞争优势研究

基于企业能力理论、交易费用理论、组织信息处理理论,以区域中小企业创新能力、交易成本、信息能力与信息需求的适配性为中间变量,分析了区域中小企业创新系统获取竞争优势的内在机理,并运用结构方程模型进行了实证研究。

中小企业金融支持体系及其运作绩效的实证分析

基于在浙江省所做的调查问卷,以系统论和过程论为理论工具,采用结构方程模型剖析了中国中小企业融资支持体系的主体的职能和作用,并从整体及其构成维度两个视角评析了融资支持体系的运作绩效,梳理了其有效运作的制约因素。研究发现,政府和中小企业的职能履行对中小企业融资支持体系运作绩效影响最大,其次是金融机构、风险投资公司,中小企业管理局的职能履行效果最差。作为中小企业融资支持体系的直接受益者,中国中小企业的职能达成度还较低。虽然各职能部门的建立和不断完善对中小企业融资支持体系的运作过程和信息沟通均有相当的促进作用,但体系内主体之间缺乏内部沟通,各主体的相应职能履行不能实现无缝衔接,内部结构上没有形成互相促进的良性循环,从而影响了整体的运作效果。