Effects of endostatin-vascular endothelial growth inhibitor chimeric recombinant adenoviruses on antiangiogenesis

AIM: To investigate the inhibitory effects of endostatinvascular endothelial growth inhibitor (VEGI151) recombinant adenoviruses on neovascularization.METHODS: We used recombinant adenoviruses to treat human vascular endothelial cell line ECV304, human hepatocellular carcinoma cell line HepG2, and murine fibroblast cell line L929, in order to study the chimeric gene expression in these cell lines. Chick choriallantic membrane(CAM) model, rabbit inflammatory corneal neovascularization(CNV) model, and liver cancer-bearing nude mice model were employed to investigate the negative biological effect of fusion molecules on neovascularization in vivo.RESULTS: Western blot showed that the molecular weight of fusion protein was about 41kD after infection of ECV304,HepG2 and L929 cells with supernatant of AdhENDO-VEGI151.The fusion protein showed a specific inhibitory effect on the proliferation of ECV304 cells, but no inhibitory effect on the growth of HepG2 and L929 cells (F=13112.13, P=0.0001). In the chick choriallantic membrane (CAM) assay, the expressed fusion protein significantly inhibited neovascularization. Rabbit inflammatory corneal neovascularization (CNV) induced by intrastromal sutures resulted in a uniform neovascular response. In this model, direct subconjunctival injection of AdhENDO-VEGI151 expressed the fusion protein in vivo and suppressed the development of CNV. Topical application of AdhENDO-VEGI151 led to a significant suppression of CNV (F=1413.11, P=0.0001),as compared with the control group of AdLacZ. Immunohistochemical staining showed the fusion protein dominantly expressed in corneal epithelium. Compared with the control group of AdLacZ (4075.9±1849.9 mm^3), the average tumor size of group AdhENDO-VEGI151 reduced in size (487.7±241.2 mm^3) (F=14.80, P=0.0085), with an inhibition rate of 88.03%. Immunohistochemical staining showed the adenoviruses carried the fusion gene expressed on liver cancer cell membrane. MVD decreased more significantly in treated mice (30.75±3.31%) than in AdLacZ control(50.25±8.65%) (F=17.72, P=0.0056) with an inhibition rate of 39%.CONCLUSION: Fusion protein expressed by recombinant adenoviruses has a significant inhibitory effect on neovascularization.

Identification of effective siRNA against K-ras in human pancreatic cancer cell line MiaPaCa-2 by siRNA expression cassette

AIM: We shall construct the small interfering RNA (siRNA) expression cassette (SEC) targeting activated K-ras gene sequence, identify more effective siRNA sequence against K-ras gene in human pancreatic cancer cell line MiaPaCa-2 by SEC and reveal the anti-cancer effects of RNA interference (RNAi) and its therapeutic possibilities. METHODS: Three different sites of SECs were constructed by PCR. K1/siRNA,K2/siRNA and K3/siRNA are located at sites 194,491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of sites 194 and 491, we detected the apoptosis in cells by FACS after they were incubated for 48 h, then we tested the alternation of K-ras gene in MiaPaCa-2 cells by RT-PCR immunofluorescence, respectively. RESULTS: Introduction of the Kl/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells leads to increased apoptosis, and the number of apoptotic cells is increased compared with control cells. The tests of RT-PCR immunofluorescence show the effects of inhibiting expression of activated K-ras gene by RNA interference in the Kl/siRNA and K2/siRNA groups. We also find that the introduction of K3/siRNA has no effect on MiaPaCa-2 cells. CONCLUSION: Kl/siRNA and K2/siRNA can inhibit the expression of activated K-ras but K3/siRNA has no effect, demonstrating that Kl/siRNA and K2/siRNA are effective sequences against K-ras gene and K3/siRNA are not. We conclude that specific siRNA against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.

Clinical and experimental study on therapeutic effect of umbilical cord blood transplantation on severe viral hepatitis

AIM: To investigate the therapeutic effect of umbilical cordblood transplantation (UCBT) on patients with severe viralhepatitis and on liver lesions in rats.METHODS: One hundred and fifty three patients with severeviral hepatitis were included in the study between April 1990and July 2002. The patients were treated with adult plasmatransfusion (control), UCBT, plasma exchange (PE) and UCBTcombined with PE (UCBT+PE) respectively. The therapeuticeffectiveness was evaluated by serial determinations of liverfunction, lipids and immune function in all patients beforeand after the treatment. The model of experimental hepaticfailure was constructed in SD rats by injecting carbontetrachloride. Then, the rats were given normal saline, adultplasma or neonate cord blood intraperitoneally. After detectionof liver function, the rats were killed and morphologicalchanges of the liver were microscopically observed.RESULTS: UCBT group and UCBT+PE group had muchbetter improvement in liver and immune functions thancontrol group and PE group. The patients in UCBT+PE grouphad the best clinical efficacy. UCBT was safe and had noside effects. The animal experiment showed significantimprovements in liver function and survival rate in neonatecord blood group as compared with adult plasma group.The histopathology of rat′s liver indicated that neonate cordblood application could decrease the liver injury and increasehepatocellular regeneration.CONCLUSION: UCBT demonstrated a good therapeuticeffect on severe viral hepatitis and no obvious side effects.Umbilical cord blood can attenuate the liver lesions andreproduce hepatocyte. The treatment of UCBT combinedwith PE was much better than that of single plasma exchange, thus UCBT can enhance the therapeutic effect of plasma exchange on severe viral hepatitis.

Numerical Simulation of Current Density Distribution in Keyhole Double-Sided Arc Welding

In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is greatly improved. To analyze the current density distribution in DSAW is beneficial to understanding of this process. Considering all kinds of dynamic factors acting on the weldpool, this paper discusses firstly the surface deformation of the weldpool and the keyhole formation in PAW+TIG DSAW process on the basis of the magnetohydrodynamic theory and variation principles. Hence, a model of the current density distribution is developed. Through numerical simulation, the current density distribution in PAW+TIG DSAW process is quantitatively analyzed. It shows that the minimal radius of keyhole formed in PAW+TIG DSAW process is 0.5 mm and 89.5 percent of current flows through the keyhole.

Synthesis of CO2 Copolymer Based Polyurethane Foams

CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.

Protective effects of scutellarin on vascular dysfunction caused by hypertension in SHR rats

OBJECTIVE To investigate the effect of scutellarin(SCU),which is the main effective component of Erigeron breviscapus(Vant.)Hand-Mazz native to Yunnan in China,on vascular dysfunction(VD)of cardiac coronary artery(CA)and cerebral basilar artery(BA)caused by hypertension in SHR rats.METHODS 1.BA and CA vesselsrings from 40 weeks of SHR rats were isolated and equilibrated in organ bath with MOPS-PSS buffer and ring tension was recorded,comparing with a normal control of WKY rats.SCU was treated accumulatively after pre-contracted with vasoconstrictor U46619(1μmol·L-1).2.ACH and SNP were treated accumulatively after pre-incubation with SCU(300μmol·L-1,100μmol·L-1)and pre-contracted by U46619(1μmol·L-1),K+60mmol·L-1,respectively.While U46619 was added accumulatively to BA/CA rings pre-incubated with SCU(300and 100μmol·L-1).ACH-induced relaxation rate was to evaluate endothelium-dependent relaxation,and SNP-induced relaxation rate to evaluate the artery non-endothelium-dependent relaxation.RESULTS SCU significantly dilated both BA and CA rings pre-contracted by U46619 in old rats.EC50 value of SCU in WKY ratswas less than that in SHR(P<0.05),which showing VD of CA and BA in SHR rats.Compared with WKY group,ACH relaxation curve of SHR group shifted to the right,suggesting that hypertension induced VD.When SCU 300μmol·L-1 pre-treated CA groups and SCU 100μmol·L-1 pre-treated BA groups,EC50 to ACH was significantly lower(P<0.05).Likewise,the vasodilatation of CA/BA rings to SNP was also improved obviously when pre-treated with SCU,and Emax to SNP was decreased significantly(P<0.05).Moreover,EC50 to U46619was significantly lower when pre-treated by SCU.CONCLUSION In SHR rats,SCU antagonized U46619 on CA/BA rings in a noncompetitive manner.Furthermore,SCU should appear to protect VD induced by hypertension.

Effects of scutellarin on PKG in HCMECs after hypoxia roxygenation

OBJECTIVE This study discusses the effects of scutellarin(SCU),which is one of effective component of Erigeron breviscapus(Vant.)Hand-Mazz,on cGMP dependent protein kinase(PKG)in human cardiac microvascular endothelial cells(HCMECs)after hypoxia roxygenation(HR).METHODS Based on a model of HCMECs cells with HR injury,cell viability is examined by MTT assay.Protein expression of PKG is analyzed by Western blotting and its enzyme activity is investigated by ELISA technology.RESULTS The results of MTT assay- indicate that SCU(1,10μmol·L1)could protect HCMECs against HR injury.SCU(0.1,1 and 10μmol·L-1)canenhance PKG-I expression in control and HR injury cells.Furthermore,SCU(1,10μmol·L-1 significantly increase PKG activity in control cells(P<0.01),and also SCU(100μmol·L-1)appears similar on enzyme activity in HR injury cells(P <0.05).CONCLUSION SCU appears protective effects on endothelial cells against HR damage.While its mechanisms may be related to the influence of SCU on PKG activity in HCMECs.

A Novel Method for Preparing Approximately Micron-sized Polymethyl Methacrylate Microspheres with Clear Surface

Polymethyl methacrylate (PMMA) microspheres with clear surface and diameter close to 1 祄 were synthesized by newly soap-free emulsion polymerization. The results showed that the presence of ethanol and NaCl made the increase of diameter and distribution, while the presence of toluene could avoid the problem of the increase of distribution, resulting a harvest of PMMA microspheres with a diameter close to 1 祄.

优质秸秆中密度纤维板的研究

在不同的蒸汽处理条件下,使用脲醛树脂将芦苇、麦秸秆压制成密度为500～700kg/m3的中密度纤维板(MDF),并研究蒸汽处理条件对板的性能的影响。对芦苇和麦秸进行蒸汽处理的蒸汽压力和处理时间分别为0.4MPa/10min和0.4MPa/5min,个别情况下,对麦秸的处理条件为0.6MPa/3min,0.6MPa/10min。蒸汽处理对麦秸的吸湿度和重量损失的影响也进行了研究。研究结果表明,秸秆中密度纤维板的机械性能随着蒸汽处理压力和时间的增加而提高;经蒸汽处理后的麦秸的秸秆吸湿性能提高;随着蒸汽处理压力和时间的增加,芦苇和麦秸重量损失增加。此外,秸秆中密度纤维板的性能明显优于秸秆刨花板,特别是内结合强度(IB),其IB值超过秸秆刨花板的IB值的10倍。除了吸水厚度膨胀率以外,麦秸MDF的所有性能都达到JIS纤维板标准要求。

The Pre-B Cell Receptor and Its Function during B Cell Development

The process of B cell development in the bone marrow occurs by the stepwise rearrangements of the V,D,and J segments of the Ig H and L chain gene loci.During early B cell genesis,productive IgH chain gene rearrangement leads to assembly of the pre-B cell receptor(pre-BCR),which acts as an important checkpoint at the pro-B/preB transitional stage.The pre-BCR,transiently expressed by developing precursor B cells, comprises the Ig μH chain,surrogate light(SL)chains VpreB and λ5,as well as the signal-transducing hetero- dimer Igα/Igβ.Signaling through the pre-BCR regulates allelic exclusion at the Ig H locus,stimulates cell proliferation,and induces differentiation to small post-mitotic pre-B cells that further undergo the rearrangement of the IgL chain genes.Recent advances in elucidating the key roles of pre-BCR in B cell development have provided a better understanding of normal B lymphopoiesis and its dysregulated state leading to B cell neoplasia.Cellular & Molecular Immunology.2004;1(2):89-94.

Novel Function of TNF Cytokines in Regulating Bone Marrow B Cell Survival

Two newly identified tumor necrosis factor (TNF) family cytokines,B cell activation factor from the TNF family (BAFF) and a proliferation-inducing ligand (APRIL),have recently been shown to enhance the maturation and survival of peripheral B cells.However,whether BAFF and APRIL are expressed in the bone marrow (BM) microenvironment and if these two cytokines modulate early B cell development remain unclear. In the present study,we have detected the abundant expression of BAFF and APRIL transcripts in BM non-lymphoid cells.Low levels of BAFF and APRIL mRNA are also found in developing B cells.Furthermore, we have determined the expression patterns of BAFF receptors during B lymphopoiesis.In cultures,both recombinant BAFF and APRIL significantly promote the survival of precursor B cells whereas only BAFF can suppress apoptosis of immature B cells.These findings suggest that BAFF and APRIL,in addition to their well established role in regulating peripheral B cell growth,can modulate the survival of developing B cells in the BM.Cellular & Molecular Immunology.2004;1(6):447-453.