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171.
大鼠肝癌模型CBRH—3的建立及其生物学特性 总被引:8,自引:0,他引:8
用DENA诱发近交系Wistar大鼠,经三个月后得原发性肝癌,移植于同品系幼鼠,从而建立了 一株染色体众数正常,AEP阳性的大鼠移植性肝癌模型,命名为CBRH-3,病理鉴定为肝细胞型肝 癌。至今已传至60余代,目前生长稳定。 相似文献
172.
173.
M. C. Léglise P. Darodes de Tailly J. L. Vignot M. A. Le Bot A.-M. Le Roux C. Riché 《Cell biology and toxicology》1996,12(1):39-53
A cellular model of hematopoiesis which would be more convenient than bone marrow (BM) progenitors and directly relevant to human pathology is needed in order to investigate xenobiotic toxicity. Human umbilical cord blood (HCB), previously shown to be able to repopulate BM, provides a powerful in vitro model of normal human hematopoiesis. In order to validate the use of normal HCB progenitors as targets for dose-related myelosuppression, we used clonogenic assays and expansion in a liquid culture of progenitor-enriched cell suspensions from HCB. A series of 8 reference molecules, doxorubicin, cytosine-arabinoside, 5-fluorouracil, 3-azido-3-deoxythymidine, acetylsalicyclic acid, sodium valproate and two cephalosporin antibiotics, were tested. In vitro 50% inhibition concentrations (IC50) were compared to those observed or reported with BM progenitors, and to the values of plasma concentrations from treated patients. HCB progenitors as in vitro targets for cytotoxic molecules were easy to access and handle, and their use was sensitive, specific and reproducible. They gave results similar to BM progenitors and allowed a qualitative approach to cellular metabolism and toxicity using morphological, flow cytometric and chromatographic methods.Abbreviations ARA-CC
cytosine arabinoside
- AS
acetylsalicylic acid
- AZTT
3-azido-3-deoxythymidine
- BFUU
burst-forming units
- BM
bone marrow
- CFU
colony-forming units
- DOXX
doxorubicin
- FU
5-fluorouracil
- glyAA
glyAcophorin A
- HCB
human umbilical cord blood
- IU
international units
- PCMEM
human placenta-conditioned medium
- VA
sodium valproate 相似文献
174.
Seiji Sonobe 《Journal of plant research》1996,109(4):437-448
Vacuoles in plant cells can be eliminated by centrifugation of protoplasts through a density gradient. In this review, properties
of evacuolated protoplasts, named ‘miniprotoplasts’, and the significant roles in plant cytoskeleton studies are described.
Miniprotoplasts, prepared from tobacco BY-2 cells whose cell-cycle had been synchronized at late anaphase, continued to divide
to form two daughter cells. In the presence of cytochalasin B cytokinetic cleavage was enhanced, suggesting a role of actin
filaments in plant cytokinesis. In the cytoplasmic extract of miniprotoplasts both tubulin and actin could be polymerized
to form microtubules (MTs) and actin filaments (AFs), respectively. A purification method for tubulin, actin and related proteins
was developed using the extract. To investigate the interaction between cortical microtubules and the plasma membrane, an
experimental system in which MTs were reconstructed on membrane ghosts was developed by combination of membrane ghosts and
the extract. 相似文献
175.
Taro Q. P. Uyeda 《Journal of plant research》1996,109(3):231-239
Recent breakthroughs and technological improvements are rapidly generating evidence supporting the “swinging lever arm model”
for force production by myosin. Unlike previous models, this model posits that the globular domain of the myosin motor binds
to actin with a constant orientation during force generation. Movement of the neck domain of the motor is hypothesized to
occur relative to the globular domain much like a lever arm. This intramolecular conformational change drives the movement
of the bound actin. The swinging lever arm model is supported by or consistent with a large number of experimental data obtained
with skeletal muscle or slime mold myosins, all of which move actin filaments at rates between 1 and 10 μm/sin vitro. Recently myosin was purified, fromChara internodal cells.In vitro the purifiedChara myosin moves actin filaments at rates one order of magnitude faster than the “fast” skeletal muscle myosin. While this ultra
fast movement is not necessarily inconsistent with the swinging lever arm model, one or more specific facets of the motor
must be altered in theChara motor in order to accommodate such rapid movement. These characteristics are experimentally testable, thus the ultra fast
movement byChara myosin represents a powerful and compelling test of the swinging lever arm model. 相似文献
176.
不同森林群落结构与光能利用率的关系 总被引:1,自引:0,他引:1
本文在人工落叶松纯林及人工落叶松与水典柳混交林的林冠观测数据的基础上建立了落叶松松和水曲柳的树冠锥体模型。通过对上述两种森林群落结构的太阳辐射的观测,利用电磁波的吸收,反射和透射理论分别对以上两种森林群落的光能利用率进行了计算。结果表明理论计算值与实测结果基本一致;双层次混交林的光能利用率高于单层纯林的光能利用率。 相似文献
177.
178.
大鹏湾反曲原甲藻种群动态机理模型辨识 总被引:7,自引:0,他引:7
建立了我国南海大鹏湾反曲原甲藻种群动态机理模型,在温度、盐度、溶解氧(DO)、可溶性无机磷(DIP)、可溶性亚硝态氮、可溶性硝态氮和酸碱度(PH值)等7个因子的分析中,辨识出温度为反曲原甲藻的限制因子;种群数量变动中引入自回归平稳随机模拟,并建立3个站位6个层面的6个自回归与非线性回归联立模型,以动态递阶的方式对反曲原甲藻种群动态进行回代,研究模型对实测值的拟合结果,拟合率达81.7%。 相似文献
179.
用二次回归旋转组合设计研究了基本亩数(X_1)、基苗氮肥(X_2)、孕穗期氮肥(X_3)、过磷酸钙(X_4)和氯化钾(X_5)用量对小麦籽粒蛋白质含量的影响.结果表明,X_4、X_1和X_2对蛋白质含量有显著作用,因素之间存在着复杂的互作效应.利用计算机模拟选优,获得了本试验条件下蛋白质含量大于13%的5个农艺因素组合方案,X_1=172.35~186.75万/ha;x_2=116.6~123.6kg/ha;x_3=33.75~39.15kg/ha;x_4=333.9~448.8kg/ha;x_5=190.65~233.10kg/ha. 相似文献
180.
经过推导,得出小麦赤霉病的两类药剂防治指标模型.在保证品质、收支有余的条件下,第一类模型附加产投比较佳、净收益最佳原则,第二类模型附加产投比最佳原则.灵敏度分析和合理性分析证明了模型的正确性.模型可做为小麦赤霉病药剂防治的决策工具.同时,给出了两类模型的BASIC计算程序. 相似文献