Ultrasound-assisted HCl-NaCl leaching of lead-rich and antimony-rich oxidizing slag.

Lead-rich and antimony-rich oxidizing slag was subjected to regular HCl-NaCl leaching, with the experimental conditions optimized under which ultrasound was introduced. After only 15 min of ultrasound-assisted leaching, the leaching rate of Sb resembled that after 45 min of regular leaching. Ultrasonic treatment considerably elevated the leaching rates of Sb and Pb, and shortened the leaching time. With the decrease of particle size, the leaching rate of Sb and Pb increased gradually. Especially, as the particle size of the slag was greater than 0.217 mm, the ultrasonic leaching effects of Sb and Pb were significantly higher than that of regular leaching effects. The temperature exhibited great effect on ultrasonic leaching performance. As the temperature increased, the leaching rates of Sb and Pb increased step by step. In case the temperature was higher than 85°C, the increasing speed of the leaching rates for Sb and Pb tended to be slow. Increasing ultrasonic power could augment the leaching rate or accelerate the procedure till the same leaching rate. However, since ultrasound failed to energize the formation of new reaction pathways, the maximum leaching rates of Sb and Pb were determined by their phase compositions rather than by ultrasonic field.

EGF Suppresses the Initiation and Drives the Reversion of TGF-ß1-induced Transition in Hepatic Oval Cells Showing the Plasticity of Progenitor Cells.

Transforming growth factor-ß1 (TGF-ß1) induces hepatic progenitors to tumor initiating cells through epithelial-mesenchymal transition (EMT), thus raising an important drawback for stem cell-based therapy. How to block and reverse TGF-ß1-induced transition is crucial for progenitors' clinical application and carcinogenic prevention. Rat adult hepatic progenitors, hepatic oval cells, experienced E-cadherin to N-cadherin switch and changed to α-smooth muscle actin (α-SMA) positive cells after TGF-ß1 incubation, indicating EMT. When TGF-ß1 plus EGF were co-administrated to these cells, EGF dose-dependently suppressed the cadherin switch and α-SMA expression. Interestingly, if EGF was applied to TGF-ß1-pretreated cells, the cells that have experienced EMT could return to their epithelial phenotype. Abruption of EGF receptor revealed that EGF exerted its blockage and reversal effects through phosphorylation of ERK1/2 and Akt. These findings suggest an important attribute of EGF on opposing and reversing TGF-ß1 effects, indicating the plasticity of hepatic progenitors.

Preparation of ultrafine cubic Sb2O3 crystals under ultrasonic.

The processes and conditions for ultrasonic preparation of cubic Sb2O3 crystals under ultrasonic by neutralizing Sb4O5Cl2 with ammonium hydroxide were researched. The effects of ultrasonic power, time and temperature as well as ratio of Sb4O5Cl2 to water on the crystal form and particle size of Sb2O3 were investigated by X-ray diffraction, scanning electron microscopy and laser particle size analyzer. Cubic Sb2O3 crystals were prepared by being sonicated at 100W and 20°C for 30min. The particles were cubic-like, with the average size of 0.777µm.

Primary isolated hepatic oval cells maintain progenitor cell phenotypes after two-year prolonged cultivation.

BACKGROUND & AIMS: Although expandable hepatic progenitors provide renewable cell sources for treatment of hepatic disorders, long-term cultivation of hepatic progenitors may affect proliferation and differentiation abilities, and even initiate the formation of malignant cancer stem cells. This study aims to determine characteristics of primary cultured hepatic oval cells after prolonged cultivation in vitro. METHODS: Hepatic oval cells isolated from rats fed with a choline-deficient, ethionine-supplemented diet were continuously propagated every 5-7 days, to 100 passages over two years. Hepatocytic differentiation was induced by sodium butyrate and characterized using western blot, periodic acid Schiff assays, albumin secretion and urea production. Proliferation capacity was evaluated using growth-curve and cell-cycle analysis; anchorage-independent growth and tumorigenicity were determined using soft agar and xenograft assay. RESULTS: After 2 years of serial passages, hepatic oval cells with typical epithelial morphology continuously expressed OV-6, BD-1, BD-2, and Dlk as markers for hepatic progenitors, cytokeratin 19 as a cholangiocyte marker, and alpha-fetoprotein and albumin as hepatocyte markers. Furthermore, sodium butyrate could induce these cells to become glycogen-storage cells with the functions of albumin secretion and ureagenesis from ammonia clearance, indicating hepatocytic differentiation. Although proliferation slightly accelerated after the 50th passage, hepatic oval cells stayed diploid cells with features of chromosomal stability, which did not acquire anchorage-independent growth capacity and caused no tumor in immunodeficient mice, suggesting no spontaneous malignant transformation. CONCLUSIONS: Hepatic oval cells retain the progenitor cell features without spontaneous malignant transformation after prolonged cultivation, and thus may serve as an expandable cell source for future exploitation of stem cell technology.

[Comparison between the suppression of tissue inhibitor of metalloproteinase-1 gene expression by recombinant adeno-associated virus carrying antisense RNA and small interfering RNA (siRNA) of TIMP-1 in rat hepatic stellate cells].

OBJECTIVES: Elevated tissue inhibitor of metalloproteinase-1 (TIMP-1) expression contributes to excess extracellular matrix in liver fibrosis. This study was designed to construct two recombinant adeno-associated viruses (AAV) carrying antisense RNA and small interfering RNA (siRNA) of TIMP-1 (rAAV/ANTI-TIMP-1/neo and rAAV/siRNA-TIMP-1/neo), and then to compare the suppression of TIMP-1 gene expression on rat hepatic stellate cell (HSC)-T6 cells infected by these two types of viruses in vitro. METHODS: Antisense RNA amplified by rat HSC-T6 and U6 promoter followed by the annealing siRNA were cloned into the AAV vector (pdl6-95/neo) and packed in 293 cells to construct the recombinants rAAV/ANTI-TIMP-1/neo and rAAV/siRNA-TIMP-1/neo. Rat HSC-T6 cells were infected with these recombinant AAVs and selected by using G418, and real-time PCR after reverse transcription and Western blot were performed to detect the transcription and expression level of TIMP-1 gene in these cells. RESULTS: The results of PCR, restrictive enzyme digestion and gene sequencing confirmed that the pdl6-95/ANTI-TIMP-1/neo and pdl6-95/siRNA-TIMP-1/neo had been reconstructed successfully. After they had been packed in 293 cells to form rAAV/ANTI-TIMP-1/neo and rAAV/siRNA-TIMP-1/neo, they were used to infect HSC-T6. Thirty days after the infection, the transcription level of TIMP-1 in HSC-T6 cells infected by rAAV/siRNA-TIMP-1/neo decreased dramatically compared with the mock control and normal HSC-T6 cells (P less than 0.01), and the expression level of TIMP-1 gene in HSC-T6 cells decreased significantly (60%), while the transcription and expression level of TIMP-1 in HSC-T6 cells infected by rAAV/ANTI-TIMP-1/neo had no significant difference with mock control and normal HSC-T6 cells (P more than 0.05). CONCLUSION: RNA interference can exert a suppression of TIMP-1 gene in rat HSC, and when this function combines with AAV infection, it can suppress the specific gene expression for a long time by chromosomal integration.

[Prospective clinical study on serum immunity in IgG-antibodies positive patients convalescent from severe acute respiratory syndrome].

OBJECTIVE: To investigate the serum immunological characteristics in patients convalescent from severe acute respiratory syndrome (SARS). METHODS: In the 1 st, 3 rd, 6 th month after their discharge, eg. SARS-IgG, T cell subsets, blood routine, and the blood biochemistry were systemically determined in SARS convalescent patients. RESULTS: The SARS-antibodies could be used as the diagnostic evidence. During the 6 months after discharge, the titers of SARS-antibodies were high, but they lowered along with passage of time. At the first recheck, the CD4(+) lymphocyte count was lower than normal level in 55.9% of patients, the CD3(+) lymphocyte count was lower than normal level in 31.2% of patients, and the CD8(+) lymphocyte count was lower than normal level in 14.0% of patients. At the second recheck, the levels of T cell subsets recovered to normal level in the most patients. CONCLUSION: T cell subsets, and the number of leukocyte are abnormal in some patients convalescent from SARS. All the indexes examined recover to normal levels half year after discharge. Therefore, it is necessary to follow up the changes in the levels of SARS-antibodies.

[Binding and inhibition of adeno-associated virus Rep78 protein with hepatitis B virus C promoter].

OBJECTIVES: Adeno-associated virus (AAV) Rep78 is known for its inhibitory effects on replication of several viruses and oncogenes transformations. The study was to investigate the effect of Rep78 on hepatitis B virus C (HBV-C) gene and the mechanism of it. METHODS: HBV-C promoter and HBV-C gene with its promoter were amplified by PCR and labeled with 32P-ATP. Electrophoretic mobility shift assay (EMSA) and in vitro transcription were utilized to detect the binding of MBP-Rep78 with HBV-C promoter and the transcription of HBV-C gene. RESULTS: EMSA showed that by increasing the amount of Rep78 protein from 0.1 microg to 1.0 microg, the binding bands got stronger in a dose-dependent manner. In addition, Rep78 antibody was used to certify the specificity of this binding. The compound of Rep78, Rep78 antibody and HBV-C promoter were seen as super shift bands in EMSA. Meanwhile, HBV-C gene transcription was significantly inhibited by in vitro transcription which meant that Rep78 could not only bind with HBV-C promoter, but also could inhibit the transcription of HBV-C gene. CONCLUSION: AAV Rep78 could inhibit the transcription of HBV-C gene through its binding with HBV-C promoter.

[Recombinant adeno-associated virus carrying hepatitis B virus C gene (rAAV-HBV-C) effectively pulses dendritic cells (DC) without affecting their maturity].

OBJECTIVE: Recombinant virus pulsated dendritic cells (DCs) may affect their survival, growth and maturity. This study is to test the infection efficiency of recombinant adeno-associated virus carrying hepatitis B core antigen (rAAV-HBV-c) to DCs and the growth and maturity of them. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy blood donors. Adherent monocytes were pulsed by rAAV-HBV-c and 293 lysate as controls on the first day of isolation. DCs were cultivated in AIM-V media with 1000 u/ml granulocyte macrophage stimulating factor (GM-CSF), 1000 u/ml interleukin-4 (IL-4) and 50 ng/ml tumor necrosis factor-alpha (TNFalpha) separately in vitro. DCs were examined at different times and the expressions of several clusters of differentiations (HLADR, CD14, CD80, CD83, CD86) were studied using FACS after being cultured for 7 days. The transcription and expression of HBV-C gene were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and intracellular staining fluorescence activated cell sorter (FACS), respectively. RESULTS: The rAAV-HBV-c infected and uninfected monocytes gradually matured and their morphology had no significant differences. The CDs expressed on the surfaces of the two groups of DCs were also similar (HLADR: 96.1% vs. 94.5%; CD86: 87.7% vs. 89.8%; CD83: 75.6% vs. 78%; CD80: 52% vs. 54.3%; CD14: 6.4% vs. 4.5%). HBV-C gene mRNA expression was measured using RT-PCR and 89.5% of the rAAV-HBV-c infected DCs showed their protein expression using FACS. CONCLUSION: rAAV-HBV-c can effectively pulse DCs without affecting the growth and maturity of them.

[Sodium butyrate induces rat hepatic oval cells differentiating into mature hepatocytes in vitro].

OBJECTIVE: To elucidate the effects of sodium butyrate on rat hepatic oval cell differentiation in vitro. METHODS: Hepatic oval cells were isolated from rats fed with a choline-deficient diet supplemented with 0.1% (w/w) ethonine for 4 to 6 weeks. The cultured hepatic oval cells were identified by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). After hepatic oval cells were treated with sodium butyrate, the morphological changes were studied through Giemsa staining and the albumin expression level was tested by Western blot. RESULTS: Immunohistochemical results showed the isolated cells were positive for both mature hepatocyte marker albumin and bile duct cell marker cytokeratin-19. Furthermore, RT-PCR results showed that the cells expressed stem cell marker c-kit, but not hematopoietic stem cell marker CD34. In short, the isolated cells were rat hepatic oval cells. 0.75 mmol/L sodium butyrate induced obvious phenotype changes of hepatic oval cells, including enlargement of the oval cells, a decrease in nucleus to cytoplasm ratio, and a 50% increase in the number of binucleated cells. Western blot results showed that 0.75 mmol/L sodium butyrate markedly raised the expression of albumin. CONCLUSION: Sodium butyrate, a differentiation promoting agent, can induce rat hepatic oval cells (liver progenitor cells) to differentiate into mature hepatocytes in vitro.