Cytoskeleton reorganization and FAK phosphorylation are involved in lanthanum （Ⅲ）-promoted proliferation and differentiation in rat osteoblasts

The effect of lanthanum ion (La³⁺) on osteoblast function and cytoskeleton is assessed in vitro. Osteoblasts were isolated from Sprague-Dawley fetal neonatal rats. Cell proliferation and gene expression levels of cbfa-1, alkaline phosphatase (ALP), osteocalcin (OC), bone sialoprotein (BSP) and osteopontin (OPN) were examined by cell counting and RT-PCR. Cytoskeleton F-actin was stained with rhodamine-conjugated phalloidin and was visualized by a confocal microscope. As the results, 10⁻⁸-10⁻⁴ M La³⁺-induced osteoblast proliferation on day 2. Data from the RT-PCR assay revealed that 10⁻⁶ M La³⁺ up-regulated the expression levels of ALP, BSP, and cbfa-1 on day 4, while it enhanced the expressions of OC and OPN on day 21. The F-actin cytoskeleton was strengthened and reorganized under the exposure of La³⁺. In addition, the phosphorylation of focal adhesion kinase (FAK) was significantly promoted in 24 h evaluated by Western blot analysis. These findings indicate that La³⁺ promotes osteoblast activity through the phosphorylation of FAK and reorganization of the cytoskeleton.     

A new class of antimagic join graphs

A labeling/of a graph G is a bijection from its edge set E(G) to the set {1,2,…,|E(G)|},which is antimagic if for any distinct vertices x anAy,the sum of the labels on edges incident to x is different from the sum of the labels on edges incident to y.A graph G is antimagic if G has an f which is antimagic.Hartsfield and Ringel conjectured in 1990 that every connected graph other than K_2 is antimagic.In this paper,we show that if G_1 is an m-vertex graph with maximum degree at most 6r+l,and G_2 is an n-vertex(2r)-regular graph(m≥n≥3),then the join graph G_1 v G_2 is antimagic.     

Fabrication of PLGA coated silica nanorattle for controlling the drug release behavior

Silica nanorattle with hollow and mesoporous structure has been proven to be an excellent drug carrier.However,how to control the drug release from silica nanorattle is still a challenge.In this study,we designed two methods,in-situ polymerization method and water in oil in water(W/O/W) double emulsion method,to coat a nanosized poly(lactic-co-glycolic acid)(PLGA) layer onto the surface of silica nanorattle for controlling the drug release behavior.Hydrophobic antitumor drug docetaxel was loaded into the PLGA coated silica nanorattle(PLGA@SN).The drug release profile,cellular uptake and cytotoxicity on human liver cancer HepG2 cells were evaluated to prove that the PLGA layer plays an effective role in tuning the drug delivery.     

On convergence of singular integral operators with respect to path of integration

Givenf being Hölder continuous in a regionG?C. For the Cauchy principal integral $$I(\Gamma ,f) = \frac{1}{{\pi i}} \int_\Gamma {\frac{{f(\zeta )}}{{\zeta - \zeta _0 }}d\zeta , \zeta _0 \in \Gamma } $$ where Γ?G is a smooth closed contour, it is established that, if a sequence of smooth closed contours Γn?G(n∈N) smoothly convergent to Γ, then the corresponding sequenceI(Γ _n, f)is convergent to I(Γ, f). Furthermore, when Γ is approximated by a sequence of complex cubic splines $S_{\Delta _n } (\Gamma )$ interpolatory to Γ, the error $|I(\Gamma ,f)--I(S_{\Delta _n } (\Gamma ,f)|$ is estimated.     

金铃子散的半仿生提取及抗癌活性研究

目的研究金铃子散的半仿生提取及抗癌活性。方法将金铃子散进行半仿生提取,提取物通过MTT法研究其抗癌活性。结果金铃子散用含20%乙醇的半仿生液提取效果较佳,且抗癌活性较好,尤其对人肝癌Hep G2细胞具有抗癌活性。结论金铃子散半仿生提取物均表现出一定的抗癌活性,为其临床抗癌应用提供科学依据。     

微分多项式分担公共值的惟一性

给出了几个关于函数F=fⁿ(f-1)²f^′和G=gⁿ(g-1)²g^′分担一个或两个公共值的惟一性定理.     

藏木香石油醚快速溶剂萃取物体外抑制肝癌细胞增殖活性研究

为充分开发利用藏药资源,对藏木香进行体外抗肝癌活性评价,并对活性部位的细胞毒活性及初步抗肝癌机制进行研究.运用快速溶剂萃取法制备藏木香的各溶剂提取物,采用MTT法、细胞形态学观察、Hoechst 33258荧光染色、流式细胞术和蛋白免疫印迹等分析藏木香各提取物抗肝癌活性及活性部位抗肝癌机制.藏木香石油醚提取物(IR-Pe)对HepG2和Hep3B都有良好的抗肝癌活性,其IC50值分别为21.9 ± 2.3 μg·mL－1、27.6 ± 2.5 μg·mL－1,且对正常肝细胞L-02在100 μg·mL－1未显示出毒性.IR-Pe对HepG2和Hep3B两个肝癌细胞株皆显示出显著的时效和量效关系;细胞形态学观察及流式细胞术显示IR-Pe明显的诱导肝癌细胞凋亡.IR-Pe明显地上调Bax和切割后的caspase-3蛋白的表达,同时下调Bcl-2蛋白的表达.IR-Pe具有良好的体外抗肝癌活性,其通过调控线粒体通路诱导肝癌细胞凋亡发挥抗肝癌活性,具有极大的开发应用潜力.     

以鼠腹腔微环境研究三氧化二砷对食管癌EC109细胞骨架的影响

目的:细胞骨架微丝是与肿瘤细胞生长密切相关的因素之一,本文以生物机体腹腔为免疫的微环境,研究化疗药物三氧化二砷(As2O3)对人食管癌细胞株微丝骨架的影响.方法:利用鬼笔环肽(Phalloidin)及碘化丙碇(Propidium Iodide,PI)标记,以流式细胞仪技术分析小鼠腹腔液中食管癌EC109细胞周期的各期细胞内F-actin的变化.结果:诱导肥大细胞(mast cell,MC)迁移入腹腔的同时,迅速升高G0/G1期细胞及降低S期细胞内的F-actin含量,DNA检测结果显示G0/G1期的肿瘤细胞数量迅速增加(p<0.05),S期细胞含量降低;三氧化二砷作用后,食管癌细胞各期的F-actin含量均降低,尤其S期为甚.MC和As2O3共同作用后,食管癌细胞各期的F-actin含量均也减少,但G0/G1期细胞数量却显著增加.结论:在小鼠腹腔微环境中,免疫功能改变(免疫细胞MC的聚集)引起G0/G1期细胞数量迅速升高、S期细胞的数量降低,可能促使EC109细胞G0/G1期向S期跨越的延迟;在此环境中,As2O3也可能通过抑制S期EC109细胞内F-actin的重组来延迟细胞从G0/G1期进入S期;诱导肥大细胞迁入腹腔的同时加入药物As2O3,其作用主要表现为短期效应,促进了肿瘤细胞内F-actin含量的降低,G0/G1期细胞数量较高,出现短暂的延迟G0/G1期向S期跨越,增强了对肿瘤细胞生长的抑制作用.因此,以生物机体为研究环境,可能更真实地呈现化疗药物对肿瘤细胞的治疗效果.     

Arylamine N-acetyltransferases: a new inhibitor of apoptosis in HepG2 cells

Objective: To explore how arylamine N-acetyltransferases (NATs) is related to cell apoptosis. Methods: NAT activity in apoptotic HepG2 cells was measured using high performance liquid chromatography (HPLC); the apoptosis rate of HepG2 cells acted upon by an NAT inhibitor was measured using flow cytometry. Results: NAT activity was lowered in apoptotic HepG2 cells; apoptosis rate induced by camptothecin (CAM) increased after inhibition of NAT activity in HepG2 cells. Conclusion: NAT can inhibit apoptosis in HepG2 cells.     

用于高效磁转染的鱼精蛋白修饰的铁氧磁性纳米粒研究

 功能化铁氧磁性纳米粒在生物医学中应用广泛,可用于肿瘤磁感应热疗、磁共振成像（Magnetic Resonance Imaging,MRI）、药物输送及磁转染等方面。为了探讨鱼精蛋白功能化修饰的铁氧磁性纳米粒的制备及其作为基因载体在体外磁转染中的可行性,采用共沉淀法制备Fe3O4磁性纳米粒,经表面氨基化修饰后在其表面偶联鱼精蛋白。利用透射电镜、傅里叶红外光谱仪、zeta电位与粒度分析仪等,对磁性纳米粒进行形态、粒径及zeta电位分析等表征检测。共聚焦显微镜观察磁转染方法转染报告基因绿色荧光蛋白质粒pEGFP-N1进入HepG2细胞的表达,以真核转染试剂vigofect为对照。结果显示,实验中制备的磁性纳米粒粒径10nm左右,在交变磁场下具有良好的升温性能。鱼精蛋白功能化修饰磁性纳米粒后,其zeta电位进一步增大,更利于与DNA有效结合,在HepG2细胞系,其转染pEGFP-N1质粒的效率高于vigofect。研究表明,鱼精蛋白功能化修饰的铁氧磁性纳米粒可作为磁转染的有效载体,由于其同时具备在交变磁场下升温的性能,在基因治疗联合热疗的研究领域具有一定的应用价值。     

美洲大蠊多肽和顺铂联用对HepG2细胞凋亡及自噬的影响

采用MTT法检测美洲大蠊多肽（PAP-3）与不同浓度的顺铂（DDP）单用或联合使用对人肝癌HepG2细胞增殖的影响；采用流式细胞术检测PAP-3、DDP单独或联合给药干预对HepG2细胞凋亡的影响；Western Blot检测PAP-3、DDP单独或联合给药后HepG2细胞内自噬相关蛋白p62、LC3、Beclin-1、Atg5及PI3K的表达。实验结果显示，与DDP单独给药相比，PAP-3与DDP联合给药对HepG2的细胞的抑制作用更强；PAP-3与DDP联合给药组中细胞的凋亡率与DDP和PAP-3单独给药组相比均有升高（P ＜ 0.05)。与对照组相比，DDP组中，p62蛋白水平降低，LC3II蛋白水平升高，LC3II/I的比例也升高，表现出细胞自噬流的活化；与DDP组相比，联合给药组中p62蛋白水平回升，LC3II蛋白水平和LC3II/I的比例均有回落。且联合给药组中PI3K、Atg5、Beclin-1等自噬相关蛋白的量均较DDP组减少，而凋亡相关的Caspase-3蛋白的表达量则较DDP组增加。据此推测，PAP-3和DDP的联用可以通过抑制HepG2细胞自噬相关蛋白的表达水平，抑制DDP带来的细胞自噬水平的升高，增加细胞对DDP的敏感性，从而诱导HepG2细胞凋亡。     

5DFRXXL region of long myosin light chain kinase causes F-actin bundle formation

Long myosin light chain kinase （L-MLCK） contains five DFRXXL motifs with ability to bind F-actin. Binding stoichiometry data indicated that each DFRXXL motif might bind each G-actin, but its biological significance remained unknown. We hypothesized that L-MLCK might act as an F-actin bundle peptides by its multiple binding sites of 5DFRXXL motifs to actin. In order to characterize F-actin-bundle formation properties of 5DFRXXL region of long myosin light chain kinase, we expressed and purified 5DFRXXL peptides tagged with HA in vitro. The properties of 5DFRXXL peptides binding to myofilaments or F-actin were analyzed by binding stoichiometries assays. The results indicated that 5DFRXXL peptides bound to myofilaments or F-actin with high affinity. KD values of 5DFRXXL binding to myofilaments and F-actin were 0.45 and 0.41 μmol/L, respectively. Cross-linking assay demonstrated that 5DFRXXL peptides could bundle F-actin efficiently. Typical F-actin bundles were observed morphologically through determination of confocal and electron microscopy after adding 5DFRXXL peptides. After transfection of pEGFP-5DFRXXL plasmid into eukaryocyte, spike structure was observed around cell membrane edge. We guess that such structure formation may be attributable to F-actin over-bundle formation caused by 5DFRXXL peptides. Therefore, we suppose that L-MLCK may be a new bundling protein and somehow play a certain role in organization of cell skeleton besides mediating cell contraction by it kinase activity.     

Mechanical,electrical, and thermal properties of the directionally solidified Bi-Zn-Al ternary eutectic alloy

A Bi-2.0Zn-0.2Al (wt%) ternary eutectic alloy was prepared using a vacuum melting furnace and a casting furnace. The samples were directionally solidified upwards at a constant growth rate (V = 18.4 μm/s) under different temperature gradients (G = 1.15–3.44 K/mm) and at a constant temperature gradient (G = 2.66 K/mm) under different growth rates (V = 8.3–500 μm/s) in a Bridgman-type directional solidification furnace. The dependence of microstructure parameter (λ) on the solidification parameters (G and V) and that of the microhardness (Hv) on the microstructure and solidification parameters were investigated. The resistivity (ρ) measurements of the studied alloy were performed using the standard four-point-probe method, and the temperature coefficient of resistivity (α) was calculated from the ρ-T curve. The enthalpy (ΔH) and the specific heat (C_p) values were determined by differential scanning calorimetry analysis. In addition, the thermal conductivities of samples, obtained using the Wiedemann-Franz and Smith-Palmer equations, were compared with the experimental results. The results revealed that, the thermal conductivity values obtained using the Wiedemann-Franz and Smith-Palmer equations for the Bi-2.0Zn-0.2Al (wt%) alloy are in the range of 5.2–6.5 W/Km and 15.2–16.4 W/Km, respectively.     

Dialdehyde starch nanoparticles as antitumor drug delivery system: An in vitro, in vivo, and immunohistological evaluation

Sustaining the release of therapeutic nanoparticles in a cell-, tissue-, or disease-specific manner is a potentially powerful technology. A new drug carrier-dialdehyde starch nanoparticle (DASNP) that can sustain the loading and release of 5-fluorouracil (5-Fu) antitumor drug is reported in this study. IR spectrophotometer and 1H NMR confirmed the formation of aldehyde groups, and scan electron microscope determinations showed that the dialdehyde starch nanoparticles obtained had an average diameter of 90 nm. 5-Fu, the model drug, was conjugated into nanoparticles by aldehyde groups. These 5-Fu-binding nanoparticles significantly enhanced breast cancer cell (MCF-7) inhibition in vitro compared with free 5-Fu. After subcutaneous 0 injection in the breast tumor-loaded rats, 5-Fu-DASNP exhibited remarkable tumor-inhibitory efficacy determined by measuring tumor weight in vivo. The tumor inhibition of 5-Fu-DASNP was 61%±6%, whereas that of free 5-Fu was only 42%±4%. Bcl-2/Bax immunohistochem-istry studies indicated that 5-Fu-DASNP remarkably induced tumor tissue necrosis. These results demonstrated that the DASNP prepared in this work is a potentially effective drug carrier.     

PHBV/葡聚糖纳米药物载体的制备及表征

两亲性聚合物纳米颗粒作为疏水性抗肿瘤药物载体因其能够增强化疗效率并降低毒副作用而受到广泛关注.采用双乳液溶剂挥发法制备了聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)/葡聚糖纳米颗粒,测得平均粒径为205.0±6.9nm,Zeta电势为-1.59±0.12mV,纳米颗粒具有明显的壳核结构,粒径均一,分散性良好.将疏水性化疗药物顺铂包载后,其粒径及电势均无明显变化,载药量达19.3±2.9%.顺铂在模拟肿瘤细胞环境pH=5.5的磷酸盐缓冲液(PBS)中比正常细胞环境pH=7.4时释放更快,且累计释放周期均长达7d以上,表明该药物载体具有一定的pH响应性以及优异的缓释性能.细胞集落形成实验表明PHBV/葡聚糖纳米药物载体具有良好的生物相容性,而载药纳米颗粒对肿瘤细胞的毒性明显高于正常细胞,表明该纳米颗粒对肿瘤细胞具有更强的杀伤作用.综上所述,PHBV/葡聚糖纳米颗粒具有两亲性分子结构,合适的粒径及Zeta电势,显著的缓释效果,对肿瘤细胞具有pH响应性及更强的杀伤作用等优势,有望成为一种新型纳米药物载体,在癌症化疗中显著提高药物利用率并降低毒副作用.     

Vertex disjoint cycles in intersection graphs of bases of matroids

The intersection graph of bases of a matroid M=(E, B) is a graph G=G~I(M) with vertex set V(G) and edge set E(G) such that V(G)=B(M) and E(G)={BB′:|B∩B′|≠0, B, B′∈B(M), where the same notation is used for the vertices of G and the bases of M. Suppose that|V(G~I(M))| =n and k_1+k_2+…+k_p=n, where k_i is an integer, i=1, 2,…, p. In this paper, we prove that there is a partition of V(G~I(M)) into p parts V_1 , V_2,…, V_p such that |V_i| =k_i and the subgraph H_i induced by V_i contains a k_i-cycle when k_i ≥3, H_i is isomorphic to K_2 when k_i =2 and H_i is a single point when k_i =1.     

Protection of phosphatidylcholine to photosystem Ⅱ membrane during heat treatment

Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PS Ⅱ)membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PS Ⅱ membrane and influenced CD spectra of PS Ⅱ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PS Ⅱ membrane. The results indicate that PC can protect PS Ⅱ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.     

Binding number,minimum degree and bipancyclism in bipartite graphs

Let G =(V_1,V_2,E) be a balanced bipartite graph with2 n vertices.The bipartite binding number of G,denoted by B(G),is defined to be n if G =K_n and min i∈{1,2}|N(S)|n min |N(S)|/|S|otherwise.We call G bipancyclic if it contains a cycle of every even length m for 4 ≤ m ≤ 2n.A theorem showed that if G is a balanced bipartite graph with 2n vertices,B(G) 3 / 2 and n 139,then G is bipancyclic.This paper generalizes the conclusion as follows:Let 0 c 3 / 2 and G be a 2-colmected balanced bipartite graph with 2n(n is large enough) vertices such that B(G) c and δ(G)(2-c)n/(3-c)+2/3.Then G is bipancyclic.     

荧光标记的叶酸修饰壳聚糖纳米载体研制

制备荧光标记的叶酸偶联壳聚糖纳米粒,为抗肿瘤药物给药系统提供载体材料。通过叶酸活性酯与壳聚糖上的氨基反应,使叶酸与壳聚糖偶联。将异硫氰基荧光素与叶酸偶联壳聚糖进行化学嫁接,以离子交联法制成具有荧光的叶酸偶联壳聚糖纳米粒,并与肝癌HepG2细胞进行体外细胞实验。实验结果表明:叶酸活性酯用量和反应温度及试剂滴加速度是影响偶联比的主要因素;在叶酸活性酯与壳聚糖用量质量比为1:1,反应温度为30℃,滴加速度为2mL/min,反应时间为12h的条件下可得到偶联稳定的叶酸偶联壳聚糖;所制得的纳米粒粒径为290nm,形态规则,细胞荧光效果明显;此方法能用于制备荧光标记的叶酸修饰壳聚糖纳米粒载体。