Association between HLA class Ⅱ gene and susceptibility or resistance to chronic hepatitis B

AIM: To investigate the association between the polymorphism of HLA-DRB1, -DQA1 and -DQB1 alleles and viral hepatitis B.METHODS: HLA-DRB1, -DQA1 and -DQB1 alleles in 54patients with chronic hepatitis B, 30 patients with acute hepatitis B and 106 normal control subjects were analyzed by using the polymerase chain reaction/sequence specific primer (PCR/SSP) technique.RESULTS: The allele frequency of HLA-DRB1*0301 in the chronic hepatitis B group was markedly higher than that in the normal control group (17.31% VS 5.67%), there was a significant correlation between them (χ2= 12.3068,Pc=0.0074, RR=4.15). The allele frequency of HLADQA1*0501 in the chronic hepatitis B group was significantly higher than that in the normal control group (25.96% VS 13.68%), there was a significant correlation between them (χ2=9.2002, PC＝0.0157, RR=2.87). The allele frequency of HLA-DQB1*0301 in the chronic hepatitis B group was notably higher than that in the normal control group (35.58%vs 18.87%), there was a significant correlation between them (χ2=15.5938, PC=0.0075, RR=4.07). The allele frequency of HLA-DRB1*1101/1104 in the chronic hepatitis B group was obviously lower than that in the normal control group (0.96% VS 13.33%), there was a significant correlation between them (χ2=11.9206, PC=0.0145, RR=18.55). The allele frequency of HLA-DQA1*0301 in the chronic hepatitis B group was remarkably lower than that in the normal control group (14.42% VS30%), there was a significant correlation between them (χ2=8.7396, Pc=0.0167, RR=0.35).CONCLUSION: HLA-DRB1*0301, HLA-DQA1*0501 and HLA-DQB1*0301 are closely related with susceptibility to chronic hepatitis B, and HLA-DRB1*1101/1104 and HLADQA1*0301 are closely related with resistance to chronic hepatitis B. These findings suggest that host HLA class Ⅱ gene is an important factor determining the outcome of HBV infection.

Targeted ribonuclease can inhibit replication of hepatitis B virus

AIM: To study the effect of a novel targeted ribonuclease(TN), the fusion protein of HBVc and human eosinophil-derived neurotoxin (hEDN), on the HBV replication in vitro.METHODS: The gene encoding the targeted ribonucleasewas cloned into pcDNA3.1 (-) to form recombinant eukaryoticexpression vector p/TN. Control plasmids, including p/hEDN,p/HBVc, and p/TNmut in which a Lys113→Arg mutation wasintroduced by sequential PCR to eliminate the ribonucleaseactivity of hEDN, were also constructed. Liposome-mediatedtransfection of 2.2.15 cells by p/TN, p/TNmut, p/hEDN, p/HBVc, and pcDNA3.1 (-), or mock transfection wasperformed. After that, RT-PCR was used to verify thetransgene expression. Morphology of the transfected cellswas observed and MTT assay was performed to detect thecytotoxicity of transgene expression. Concentration of HBsAgin the supernatant of the transfected cells was measuredusing solid-phase radioimmunoassay.RESULTS: Transgenes were successfully expressed in 2.2.15cells. No obvious cytotoxic effect of transgene expressionon 2.2.15 cells was found. The HBsAg concentration in thep/TN transfected cells was reduced by 58 % compared withthat of mock transfected cells. No such an effect was foundin all other controls.CONCLUSION: The targeted ribonuclease can inhibit HBVreplication in vitro while it has no cytotoxicity on host cells.The targeted ribonuclease may be used as a novel antiviralagent for human HBV infection.

Stable transfection of extrinsic Smac gene enhances apoptosis-inducing effects of chemotherapeutic drugs on gastric cancer cells

AIM: TO explore the feasibility of enhancing apoptosis-inducing effects of chemotherapeutic drugs on human gastric cancer cells by stable transfection of extrinsic Smac gene. METHODS: After Smac gene was transferred into gastric cancer cell line MKN-45, subclone cells were obtained by persistent G418 selection. Cellular Smac gene expression was determined by RT-PCR and Western blotting. After treatment with mitomycin (MMC) as an apoptotic inducer, in vitro cell growth activities were investigated by trypan blue-staining method and MI-I colorimetry. Cell apoptosis and its rates were determined by electronic microscopy, annexin V-FITC and propidium iodide staining flow cytometry. Cellular caspase-3 protein expression and its activities were assayed by Western blotting and colorimetry. RESULTS: When compared with MKN-45 cells, the selected subclone cell line MKN-45/Smac had significantly higher Smac mRNA (3.12±0.21 vs0.82:1:0.14, t=7.52, P<0.01) and protein levels (4.02±0.24 vs0.98:1:0.11, t=8.32, P<0.01). After treatment with 10μg/mL MMC for 6-24 h, growth inhibition rate of MKN-45/Smac (15.8±1.2-54.8±2.9%) was significantly higher than that of MKN-45 (5.8±0.4-24.0±1.5%, t = 6.42, P<0.01). Partial MKN-45/Smac cancer cells presented characteristic morphological changes of apoptosis under the electronic microscope with an apoptosis rate of 36.4=1=2.1%, which was significantly higher than that of MKN-45 (15.2±0.8%, t = 9.25, P<0,01). Compared with MKN-45, caspase-3 expression levels in MKN-45/Smac were improved significantly (3.39±0.42 vs 0.96:1:0.14, t=8.63,P<0.01), while its activities were 3.25 times as many as those of MKN-45 (0.364±0.010 vs 0.112:1:0.007, t= 6.34, P<0.01). CONCLUSION: Stable transfection of extrinsic Smac gene and its over-expression in gasbic cancer cell line can significantly enhance cellular caspase-3 expression and activities, ameliorate apoptosis-inducing effects of mitomycin C on cancer cells, which is a novel strategy to improve chemotherapeutic effects on gastric cancer.

Effect of vector-expressed siRNA on HBV replication in hepatoblastoma cells

AIM: To study the effect of siRNA expressed from DNA vector on HBV replication.METHODS: Human U6 promoter was amplified from genomic DNA and cloned into plasmid pUC18 to construct a mammalian siRNA expression vector pUC18U6. Then oligonucleotides coding for a short hairpin RNA against HBV were cloned into pUC18U6 to form pUC18U6HBVsir which was introduced into 2.2.15 cells by using liposome-mediated transfection.2.2.15 cells transfected by pUC18U6 and pUC18U6GFPsir which expressed siRNA against green fluorescent protein and mock-transfected 2.2.15 cells were used as controls.Concentration of HBsAg in the supernatant of the transfected cells was measured by using solid-phase radioimmunoassay.RESULTS: A mammalian siRNA expression vector pUC18U6 was constructed successfully. Compared with controls,pUC18U6HBVsir which expressed siRNA against HBV decreased concentration of HBsAg significantly by 44%(P<0.05).CONCLUSION: HBV replication in 2.2.15 cells is inhibited by siRNA expressed from the DNA vector.

Effect of vector-expressed shRNAs on hTERT expression

AIM: To study the effect of short hairpin RNAs (shRNAs)expressed from DNA vector on hTERT expression.METHODS: Oligonucleotides coding for four shRNAs against hTERT were cloned into a mammalian shRNA expressionvector pUC18U6 to form pUC18U6ht1-4, which were thenintroduced into HepG2 cells by using liposome-mediated transfection. HepG2 cells transfected by pUC18U6 and pUC18U6GFPsir, which expressed shRNA against green fluorescent protein (GFP), were used as controls. hTERT mRNA in the transfected cells were quantified by using real-time fluorescent RT-PCR.RESULTS: Among the four shRNAs against hTERT, two decreased the hTERT mRNA level. Compared with the controls, pUC18U6ht which expressed the two shRNAs reduced hTERT mRNA by 39% and 49% (P＜0.05).CONCLUSION: hTERT expression is inhibited by the shRNAs expressed from the DNA vector.

Anti-HBV activity of TRL mediated by recombinant adenovirus

AIM: To investigate the inhibitive effect of hepatitis B virus (HBV)-TRL on HBV replication. METHODS: Based on previously constructed pcDNA3.1 (-)/TRL, TR, TRmut, HBV core protein (HBVc) and hEDN, interest gene sequences TRL, TR, HBVc and hEDN were inserted into adenovirus shuttle plasmid pDC316 respectively and co-transfected HEK293 cells with rescue plasmid pBHGlox(delta)E1,3Cre to acquire RAd/TRL, TR, HBVcand hEDN. And then RAds were identified, amplified and the titers in HEK293 cells were determined. RAd/TRL and TR were named as the experimental groups, and others were control ones. After HepG2.2.15 cells were infected, RAd/TRL expression was identified by indirect immunofluorescence staining. Supernatant HBV-DNA content was determined by fluorescent quantification PCR. Meanwhile, metabolism of HepG2.2.15 cells was evaluated by MTT colorimetry.RESULTS: RAd vectors with distinct interest gene sequence were successfully constructed. Effective expression of RAd/TRL in HepG2.2.15 cells resulted in a significant decrease of supernatant HBV-DNA content compared to RAd/TR (0.63±0.14 vs 1.60±0.47, P = 0.0266, ＜0.05) andother control groups (0.63±0.14 vs 8.50±2.78, 8.25±2.26,8.25±2.29, 8.50±1.51, 8.57±1.63, P＜0.01). MTT assaysuggested that there were no significant differences in cell metabolic activity between groups (P＞0.05).CONCLUSION: The construction and expression of RAd/TRL has been achieved and it could inhibit HBV replication successfully, which has laid the foundation for further research on anti-HBV activity in vivo.

Nanosized SnO_2 Particles Dispersed on a Graphite Electrode for Selective Detection of Dopamine and Ascorbic Acid

A novel nano-SnO2/graphite electrode has been prepared via polishing procedure to produce active and stable surface. The modified electrode resolves the overlapping voltammetric response of dopamine and ascorbic acid into two well-defined peaks by 230 mV. The mechanism of discrimination of dopamine from ascorbic acid is discussed. Dopamine and ascorbic acid can be determined simultaneously with the modified electrode. The electrode shows good sensitivity, selectivity and stability.

Cryopreservation and gel collagen culture of porcine hepatocytes

AIM: To study the method of cryopreserving porcine hepatocytes and gel collagen culture measure after its cryopreservation. METHODS: Hepatocytes, isolated from Chinese expedmental suckling mini-pigs by two-step perfusion with collagenase using an extra corporeal perfusion apparatus, were cryopreserved with 50 mL/L to 200 mL/L DMSO in liquid nitrogen for 4 mo, then thawed and seeded in 1 or between 2 layers of gel collagen. The expression of porcine albumin message RNA, cellular morphology and content of aspartate aminotransferase (AST) and urea nitrogen (UN) were examined during culture in gel. RESULTS: Viability of 150 mL/L DMSO group thawed hepatooltes was (83±4)%, but after purification, its viability was (90±5)%, attachment efficiency was (86±7)%, the viability of thawed hepatocytes was near to fresh cells. When the thawed hepatooltes were cultivated in gel collagen with culture medium adding epidermal growth factor, the hepatocytes grew in various administrative levels in mixed collagen gel, and bunchy in the sandwich configuration cultures. For up to 10 days' culture, the typical cellular morphological characteristics of cultivated hepatocytes could be observed. The leakage of AST was lower during culture in gel than that in common culture. At the same time, the UN synthesized by cells cultivated in mixed gel collagen was higher than that in other groups. CONCLUSION: Storage in liquid nitrogen can long keep hepatocytes' activities, the concentration of 150 mL/L DMSO is fit for porcine hepatooltes' cryopreservation. Thawed hepatocytes can be cultivated with collagenous matrix, which provides an environment that more closely resembles that in vivo and maintain the expression of certain liver-specific function of hepatocytes.

Scheduling and control of failure prone systems with demand uncertainty and job overlaps

Given that the overlapping of jobs is permitted, the paper studies the scheduling and control of failure prone production systems, i.e. so-called settings with demand uncertainty and job overlaps. Because a variable demand resource is involved in the production and corrective maintenance control problems of the system, which switched randomly between zero and a maximum level, it is difficult to obtain the analytical solutions of the optimal single hedging point policy. An asymptotic optimal scheduling policy is presented and a double hedging point policy is offered to control simultaneously the production rate and the corrective maintenance rate of the system. The corresponding analytical solutions and approximate solutions are obtained. Considering the relationship of production, corrective maintenance and demand variable, an approximate optimal single hedging point control policy is proposed. Numerical results are presented.

Effect of Gas Antisolvent on Conformation of Polystyrene in Tolene：Viscosity and Small—Angle X—ray Scattering Study

Synchrotron radiation small-angle X-ray scattering(SAXS) and the viscosity technique were used to investigate the effect of dissolved CO2 in toluene on the conformation of polystyrene(PS) in the solution.The viscosity of PS solution decreases faster with increasing antisolvent CO2 pressure than that of the solvent in the absence of the polymer.the intrinsic viscosity [η] calculated using the wellknown Huggins equation decreases with antisolvent pressure.It was found that the second virial coefficient A2 and the apparent mean-square radius of gyration<Rg^2>^1/2 decreases with pressure of antisolvent CO2.All these phenomena can be attributed to the shrink of PS chain in the course of adding the gas antisolvent because the intercation between the polymer and solvent becomes weaker.The values<Rg^2>^1/2 at different pressures obtained from SAXS data agree reasonably with those calculated from Flory theory using the viscosity data determined in this work.This implies that Flory theory,which has been used widely for the solutions of polymers in liquid solvents,is also applicable to the polymer solution with gas antisolvent.