Metal-free visible-light-driven cascade cyclization reaction to synthesize 2-oxindoles via benzoyl and phenylsulfinyl radicals with acrylamide derivatives.

A metal-free visible-light-driven cascade cyclization reaction to synthesize 3-methyl-3-acetophenone-2-oxindoles and 3-methyl-3-(methylsulfonyl)benzene-2-oxindoles in yields up to 96% and 99%, via benzoyl and phenylsulfinyl radicals with acrylamide derivatives is reported, respectively. Extensive studies, including gram-scale, radical capture and isotope experiments, were performed to indicate that the reaction may involve a radical process.

[The effect of envelope protein mutation on hepatitis B virus assemble].

OBJECTIVE: To investigate the effect of envelope protein mutation on HBV assembly. METHODS: The envelope protein mutated vectors were constructed by the molecular clone in vitro, and then transfected transiently in the cell HepG2. The expression and secretion of S protein was assay by ELISA. HBV DNA was quantitatively evaluated by PCR. After co-transfection with pHBV-mS1S and adwR9 the DNA was quantitatively evaluated by PCR. RESULTS: There was no significant difference in expression and secretion of S protein assayed by ELISA in the cytoplasm and supernatant among pHBV-mS1, pHBV-mS, pHBV-mS1S and the wild HBV adwR9 plasmid. The DNA detected by real-time fluorescence quantitative PCR from those the cytoplasm of mutants was higher than that from the wild HBV adwR9 cytoplasm, especially from the cytoplasm of pHBV-mS1S plasmid. However, the DNA detected by real-time fluorescence quantitative PCR from the supernatant of those mutants was lower than that from the wild HBV adwR9 supernatant, especially from pHBV-mS1S. The DNA detected by real-time fluorescence quantitative PCR from the supernatant co-transfected with pHBV-mS1S and adwR9 was lower than that from the supernatant co-transfected with pcDNA3 and adwR9. CONCLUSION: There was no effect of envelope protein mutation on the expression and secretion of S protein. Envelope protein mutation could interfere the assembly of HBV particle and cause reduction of secretion of HBV.

[Cloning of human telomerase reverse transcriptase promoter for targeted cancer therapy].

OBJECTIVE: An human telomerase reverse transcriptase (hTERT) promoter was cloned to investigate the effect of simplex virus-thymidine kinase (HSV-tk) gene-ganciclovir (GCV) system under control of this promoter on lung cancer cells A549. METHODS: Specific primers were designed to amplify the core hTERT promoter from HepG2 genome. A set of expression vectors encoding LacZ or tk gene under control of hTERT or hCMV promoter was constructed through standard molecular cloning methods. After the transfection with lipofectamine 2000, reverse transcriptional PCR (RT-PCR) and beta-Gal staining were performed to examine the activity of the hTERT promoter. The cytotoxic effects of GCV/tk on A549 and MRC5 cells transfected with the plasmids encoding tk gene were evaluated by MTT assay. RESULTS: The hTERT promoter containing -208-+40 bp of the upstream sequence of human telomerase was successfully cloned. beta-Gal staining and RT-PCR were used to detect the expression of Lac Z and the transcription of tk gene under control of the hTERT promoter, respectively, in A549 rather than MRC5 cells. Cyototoxic effect of GCV was observed only in the A549 but not MRC5 cells after the transfection with pDC511 hTERT/tk, and the effect was dose-dependent. The effect, however, was observed in cells transfected with pDC518 hCMV/tk. CONCLUSION: The hTERT promoter cloned in this study can specifically control the target gene expression in telomerase-positive tumor cells but not the normal cells, suggesting that the HSV-tk/GCV system under control of the hTERT promoter is a promising targeted gene therapy for malignant tumors.

[Study of mouse marrow cells differentiation into a hepatocyte lineage in vitro].

OBJECTIVE: To explore whether bone marrow stem cells (MSCs) from adult mice can be induced to differentiate into hepatocytes by hepatocyte growth factor (HGF) alone and the time phase characteristics in the differentiation progress. METHODS: Adult mouse MSCs were treated with or without 100 ng/ml HGF, on days 0, 7, 14, 21, and 28. The morphologic characteristics of the cells were examined; the albumin (ALB), AFP mRNA was analyzed sub-quantively using reverse transcription polymerase chain reaction (RT-PCR) and immumohistochemistry techniques. The expression of ALB, AFP and CK19 were detected by using anti-ALB, AFP and CK19 antibodies. RESULTS: Freshly isolated adult mouse MSCs expressed ALB and AFP mRNA weakly; in the group without HGF, no ALB mRNA was detected on day 7. The expression of AFP mRNA was reduced significantly on day 7, and could not be detected anymore after day 14. In the HGF treated group, ALB mRNA was not detected on day 7, but the positive lane appeared again on day 14, and the expression of ALB mRNA was increased on day 21 but reduced in the following days. The AFP mRNA was positive at all times, however it tended to decrease after day 14 in the HGF treated groups. The result of immumohistochemistry was consistent with that of RT-PCR, and CK19 was always negative. CONCLUSION: Adult mouse MSCs can be induced into hepatocyte differentiation in vitro. The optimal time for the induction was 2 to 3 weeks.

[Study on anti-HBV effects of genetically engineered replication-defective hepatitis B virus expressing dominant negative mutants of core protein].

BACKGROUND: To explore the possibility of using HBV as a gene delivery vector, and to test the anti-HBV effects by intracellular expression of dominant negative mutants of core protein. METHODS: Two kinds of full length mutant HBV genome, which express Core-partial P and Core-S fusion protein, were transfected into HepG 2.2.15 cell lines. Positive clones were selected and mixed in respective groups with hygromycin in the culture medium. HBsAg and HBeAg, which exist in the culture medium, were tested by ELISA and intracellular HBc related HBV DNA was examined by dot blot hybridization. The existence of recombinant HBV virion in the culture medium was examined by PCR. RESULTS: The mean inhibitory rates of HBsAg were 2.74+/-3.83%, 40.08+/-2.05% (P less than 0.01) and 52.94+/-1.93% (P less than 0.01) in group 2.2.15-pMEP4, 2.2.15-CP and 2.2.15-CS, respectively. The mean inhibitory rates of HBeAg were 4.46+/-4.25%, 52.86+/-1.32% (P less than 0.01) and 41.60+/-1.65% (P less than 0.01), respectively. The inhibitory rates of HBc related HBV DNA were 15.3%, 82.0% and 67.2%, respectively. Recombinant HBV virion was detectable in the culture medium of only group 2.2.15-CP. CONCLUSION: Dominant negative mutants of core protein can efficiently suppress wt-HBV replication and the expressions of HBV antigens. With the help of wild-type HBV, the recombinant HBV genome can form and secret HBV like particles, which provides evidence that the antiviral gene will be hepatotropic expression and the antiviral effects will be amplified.

[Development of hygromycin-resistant packaging cell line for hepatitis B virus-derived vectors].

OBJECTIVE: To cooperate with the study of HBV vector, hygromycin-resistant packaging cell line was developed that allows encapsidation of plasmids into HBV particles. METHODS: Free of packaging signal, HBV genome was inserted into plasmid pMEP4, which expresses the HBV structural proteins including core, pol and preS/S proteins. HepG2 cell lines were employed to transfect with the construct. Hygromycin selection was done at a concentration of 150 micrograms/ml in the culture medium. The hygromycin-resistant clones with the best expressions of HBsAg and HBcAg were theoretically considered as packaging cell line and propagated under the same conditions. It was infected with recombinant retrovirus vector and hen selected with G418 and hygromycin in the culture medium. The existence of recombinant HBV virion in the culture medium was examined by PCR. RESULTS: Hygromycin-resistant HBV packaging cell line was generated, which harbored an HBV mutant whose packaging signal had been deleted. Expressions of HBsAg and HBcAg were detectable. Infected with recombinant retrovirus pRV-CP, the hygromycin-resistant packaging cell line was found to secrete mutant HBV particles and no wild-type HBV was detectable in the culture medium. CONCLUSION: After the packaging signal was deleted and transfected into HepG2 cell lines, the partial HBV genome lost its ability to form wild-type HBV, but conserves cis-action providing structural proteins for the packaging of the replication-defective HBV.

[Replication and encapsidation of HBV mutants with the truncated C gene].

OBJECTIVE: To evaluate the replication and encapsidation of HBV mutants with the truncated C gene. METHODS: The HBV mutants with the truncated C gene were constructed by molecular cloning and PCR-based deletion in vitro. The replication and encapsidation of HBV mutants were investigated by Southern blotting, PCR and real-time fluorescence PCR respectively after transfecting the HBV mutants plasmid into HepG2 cells by using liposome. RESULTS: The C-truncated HBV mutant vectors were constructed successfully and confirmed exactly by clone sequencing and enzymes digestion. The C-truncated HBV mutants were replication defective, however, all types of HBV DNA could be detected positive in the cytoplasm and supernatant after co-transfecting the C-truncated HBV mutants plasmid and the helper constructs into HepG2 cells. The C-truncated HBV mutants were proved to produce 3-40 folds more progeny DNA than that of the wild-type HBV by DNA quantitative assay. CONCLUSION: The C-truncated HBV mutants are replication-deficient and could not replicate and encapsulate in the hepatocytes when transfected solely, however, the progeny HBV-variant viruses are encapsidated more effectively to secrete into supernatant when co-transfected with the helper construct which lacks part of 5 prime-proximal HBV RNA packaging signal Epsilon.

[The anti-HBV effect and mechanism of C gene truncated mutant in vitro].

OBJECTIVE: To explore the effect and mechanism on HBV replication in C gene truncated mutant. METHODS: Protein expression of C gene truncated vector and wild C gene vector were assay by SDS-PAGE Western blot. Constructed C gene truncated expression vector was cotransfected with wild HBV genome; virus load was detected by PCR in the culture medium and the cell. The formation of core particle was assay by Native western blot. RESULTS: The recombinant vectors can efficiently express. Virus load of the cotransfected group by pcDNA3-deltaC and adwR9 was lower than that of control group in the culture medium and the cell. Protein band of the co-expressed group by pcDNA3-deltaC and pcDNA3-C showed slightly weaker than that of the co-expressed group by pcDNA3 and pcDNA3-C. CONCLUSION: C gene truncated mutant could interfere with the formation of core particle and reduce of HBV replication

[Approach to transforming hepatitis B virus as a gene therapeutic vector].

OBJECTIVE: To evaluate the possibility of hepatitis B virus (HBV) as a vector in liver-targeting gene therapy. METHODS: A fragment containing the small envelope gene of HBV was replaced with the reporter gene green fluorescent protein (GFP) to construct the recombinant HBV vector, which was transfected into HepG2 cells with liposome. The expression of GFP was observed with fluorescence microscope. The HBV cccDNA was testified using semi-nest PCR. The viral particles of the recombinant HBV in culture medium were detected by PCR as well as Southern blot. RESULTS: The HBV vector carrying the interesting gene of GFP could express the functional protein in the transfected hepatocytes. However, the recombinant HBV vector was replication-deficient, which could not be packed and replicated in the hepatocytes to secrete mature recombinant HBV particles carrying the interesting gene of GFP when transfected solely but could when cotransfected with the recombinant and helper construct which lacked part of 5'-proximal HBV RNA packaging signal epsilon. CONCLUSION: It is possible that HBV is reconstructed as a liver-targeting vector for gene therapy.

[Mitogenic effects of growth and differentiation factors on rat liver stem cell WB-F344 in vitro].

OBJECTIVE: To explore the relationship between the proliferation, differentiation of rat hepatic stem like cell line WB-F344 and cytokines in vitro. METHODS: (3)H thymidine labelling of new synthesized DNA was used to examine the mitogenic responsiveness of WB-F344 cells to cytokines, western blot was used to study the expression of cytokines receptors on hepatic stem cells, and apoptotic cells were detected by Flow cytometry. RESULTS: WB-F344 cells showed a proliferative response to the cytokines of hepatocyte growth factor (HGF), epidermal growth factor (EGF), fibroblast growth factor (FGF), Insulin at the dose of 80 ng/ml, and the relative cpm values are 982.95, 906.32, 863.98 and 968.67 respectively, while non response to interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) at the same dose, and an inhibition or apoptosis response to transforming growth factor-beta (TGF-beta) at 80 ng/ml with a 26.89% apoptotic rate. Western blot showed that there were HGF, EGF, FGF, TGF-beta receptors expressed on WB-F344 cells. When WB-F344 cells were cultured in the differential system (DMEM, 10% Fcs, HGF 10 to approximately 50 ng/ml, EGF 20 ng/ml, Insulin 1 microg/ml, Dex 1 micromol/L), the cells could differentiated into hepatocytes. In addition, HGF could scattered WB-F344 cells. CONCLUSION: The proliferation and differentiation of liver stem cells are regulated by various cytokines which may play an important role when liver is damaged seriously.

[Anti-HBV effects of genetically engineered replication-defective HBV with combined expression of antisense RNA and dominant negative mutants of core protein and construction of first-generation packaging cell line for HBV vector].

OBJECTIVE: To explore the possibility of using HBV as a gene delivery vector, and to test the anti-HBV effects by intracellular combined expression of antisense RNA and dominant negative mutants of core protein. METHODS: Full length of mutant HBV genome, which expresses core-partial P fusion protein and/or antisense RNA, was transfected into HepG2.2.15 cell lines. Positive clones were selected and mixed in respective groups with hygromycin in the culture medium. HBsAg and HBeAg, which exist in the culture medium, were tested by ELISA method. Intracellular HBc related HBV DNA was examined by dot blot hybridization. The existence of recombinant HBV virion in the culture medium was examined by PCR. Free of packaging signal, HBV genome, which express the HBV structural proteins including core, pol and preS/S proteins, was inserted into pCI-neo vector. HepG2 cell lines were employed to transfect with the construct. G418 selection was done at the concentration of 400mug/ml in the culture medium. The G418-resistant clones with the best expression of HBsAg and HBcAg were theoretically considered as packaging cell lines and propagated under the same conditions. It was transfected with plasmid pMEP-CPAS and then selected with G418 and hygromycin in the culture medium. The existence of recombinant HBV virion in the culture medium was examined by PCR. RESULTS: The mean inhibitory rates of HBsAg were 2.74% 3.83%, 40.08 2.05% (t=35.5, P<0.01), 66.54% 4.45% (t=42.3, P<0.01), and 73.68% 5.07% (t=51.9, P<0.01) in group 2.2.15-pMEP4, 2.2.15-CP, 2.2.15-SAS, and 2.2.15-CPAS, respectively. The mean inhibitory rates of HBeAg were 4.46% 4.25%, 52.86% 1.32% (t=36.2, P<0.01), 26.36% 1.69% (t=22.3, P<0.01), and 59.28% 2.10% (t=39.0, P<0.01), respectively. The inhibitory rates of HBc related HBV DNA were 0, 82.0%, 59.9%, and 96.6%, respectively. Recombinant HB virion was detectable in the culture medium of all the three treatment groups. G418-resistant HBV packaging cell line, which harbored an HBV mutant whose packaging signal had been deleted, was generated. Expression of HBsAg and HBcAg was detectable. Transfected with plasmid pMEP-CPAS, it was found to secrete recombinant HB virion and no wild-type HBV was detectable in the culture medium. CONCLUSIONS: It has stronger anti-HBV effects by combined expression of antisense RNA and dominant negative mutants than by individual expression of them. With the help of wild-type HBV, the modified HBV genome can form and secret HBV like particles, which provides evidence that the antiviral gene will be hepatotropic expression and the antiviral effects will be amplified. The packaging cell line can provide packaging for replication-defective HBV, but with low efficiency.

[The development of FSCLZLY--an ascites-ultrafiltration instrument].

It's known to all that the refractory ascites treatment has so far been a very difficult clinical problem. We have extracted much experience from the practical techniques used in the refractory ascites treatments of more than 1,000 cases, and have developed the ascites ultrafiltration & concentration therapeutic instrument--FSCLZLY-A. The clinical applications show that it is very effective. Its effective rate is about 72.08%. Therefore, it is a very useful and important medical device for refractory ascites, for the improvement of renal function, and for the prevention of the infection of abdominal cavity.