BACKGROUND: Under the cellular physiological condition, 15.3% N-acetylated chitosan has poor solubility which limits cellular microencapsulation process.OBJECTIVE: This study was designed to prepare 50% N-acetylated chitosan with 15.3% N-acetylated chitosan and investigate its feasibility for preparing chitosan microcapsule used for hepatocyte embedding after in conjunction with methacrylic acid-hydroxyethyl methacrylate-methyl methacrylate (MAA-HEMA-MMA) copolymer under the cellular physiological condition.DESIGN, TIME AND SETTING: This study, a control observation experiment, was performed at the Central Laboratory, First Hospital Affiliated to Jinan University, Guagnzhou, Guangdong Province, China between January and October 2006.MATERIALS: 15.3% N-acetylated chitosan was provided by Sigma-Aldrich Company, Singapore. Hepatocytes were acquired from male Wistar rats, weighing 250-300g, by two-step collagenase digestion method.METHODS: Hepatocytes were microencapsulated using 50% N-acetylated chitosan and MAA-HEMA-MMA copolymer at 25℃ under aseptic condition.MAIN OUTCOME MEASURES: Microcapsule permeability was expressed with the diffusion degree of fluorescein isothiocyanate (FITC)-dextran in the empty microcapsule. The homeostasis of microencapsulated hepatocytes was measured by mechanical shearing-crush tests. The albumin-synthesizing capability of microencapsulated hepatocytes was determined by enzyme-labeled immunosorbent assay (ELISA). Urea-synthesizing capability was tested using kits (Sigma Diagnostics, USA) at the wavelength of 540 nm by colorimetric assay. Cytochrome P450 activity was determined using confocal laser microscopes and quantitated by the fluorescence intensity of products of 0-dealkylated 7-ethoxy resorufin, a substrate of cytochrome P450IA1. The plate-cultured hepatocytes were taken as controls.RESULTS: With increasing mass concentration of 50% N-acetylated chitosan, the diffusion degree of Mr 20000 and Mr 40000 FITC-dextran presented with a decreasing tendency, while the diffusion degree of Mr 70000 FITC-dextran was low and did not alter markedly. When the microencapsulated hepatocyte density was 2×109 L-1, the broken rate of microcapsule was only about 6% after 24 hours of shaking. Under the same condition of shaking, empty microcapsules were all broken after 4 hours of shaking. After 1 day of culture, approximately 30μmol/d urea could be synthesized among 1×106 bepatocytes that was markedly higher than the plate culture experimental result, 15μmol/d. After 7 days of culture, urea-synthesizing capability was close between in the microencapsulated hepatocytes and in the plate cultured hepatocytes. In the first 3 days of culture, 10μg/d albumin was acquired from 1×106 hepatocytes, and after 7 days of culture, only about 5μg/d albumin was obtained. The albumin level in the whole culture process was higher than plate culture results. After 1 day of culture, cytochrome P450 activity in the microencapsulated hepatocytes was higher approximately 8 times compared to plate culture results. After 1 week of culture, cytochrome P450 activity still retained at 50% of 1-day culture level.CONCLUSION: Microcapsule prepared by 50% N-acetylated chitosan under the physiological condition has good permeability and structural stability during the process of culture. Compared with in vivo surface culture test, degenerated chitosan microcapsule is better favorable to in vitro function of hepatocytes.

BACKGROUND: Organ for transplantation is insufficient, and primary transplant of nonfunction caused by perfusion cryopreservation occasionally occurs. It is clinically significant to reduce organ damage caused by perfusion preservation. OBJECTIVE: To explore the protective effect of hyperoxic perfusion fluid on liver transplantation in rats. METHODS: A total of 40 Wistar rats were randomly divided two groups (n = 20) and respectively poured with Ringer lactate solution or hyperoxic ringer lactate solution. Each group comprised equal number of donors and recipients to prepare liver, kidney, and pancreas transplantation models. Hyaluronic acid (HA), alanine aminotransferase (ALT) and CD8+CD28- T cells were compared between two groups at the end of perfusion, and 1st and 3rd days after liver transplantation. The acute rejection score of liver tissues were also compared after operation. RESULTS AND CONCLUSION: The HA, ALT and CD8+CD28-T cells were no significantly different between two groups before operation (P> 0.05). The HA and ALT of hyperoxic ringer lactate solution group was significantly Ringer lactate solution group after liver transplant (P < 0.05), but the CD8+CD28-T cells were greater (P < 0.05). The acute rejection scores for liver in hyperoxia liquid group were significantly less than the common liquid group (P< 0.05). Results show that hyperoxic solution can attenuate ischemia/reperfusion injury and protect rats undergoing liver transplantation.

0.05); in with ser um condition, the transfection efficiency in Dosper group was significant hi gher than that in Lipofectamine group (P

Objective To construct the retroviral vector inserted SV40 large T antigen gene and transfect it into rat hepatocytes, analyze the status of SV40 large T antigen gene expression in rat hepatocytes, and to establish important basis for clinical hepatocytes transplanation. Methods Retroviral vector inserted SV40 large T antigen gene was(constructed) by DNA recombinant techniques in vitro, then the combinant vector was determined with enzyme(digestion) and sequencing and was transfected into the PA317 cell lines by liposome mediation and screened(anti-G4)18 positive clones. The viral titer was determined with the NIH3T3. After transfected into separated and purified rat primary hepatocytes, the SV40 large T antigen gene expression was detected by PCR and immunohistochemical (methods). Results (1)SV40 large T antigen gene fragment was inserted into retroviral vector in sense orientation. (2)The titer of pseudovirion packed by PA317 cell lines was 1.3?10~6CFU/ml. (3)SV40LT antigen gene was(integrated) into rat primary hepatocytes and its expression in transfected cells at 24 hour was higher than 96 hour (P

BACKGROUND:Bioartificial liver could partial y replace the major liver functions, including detoxification, synthesis, secretion and biotransformation. OBJECTIVE:To use bibliometric indexes to track study focuses on bioartificial liver, and to investigate the relationships among geographic origin, impact factors, and highly cited articles indexed in Web of Science. METHODS:A list of citation classics for bioartificial liver was generated by searching the database of Web of Science-Expanded using the terms“artificial liver support system”or artificial liver or“bioartificial liver”. The top 33 cited research articles which were cited more than 100 times were retrieved. RESULTS AND CONCLUSIONS:Of 4 144 articles published, the 33 top-cited articles were published between 1992 and 2010. The highest citations paper was published in 2002, with a total of 668 citations, mean cited 55.67 per year. The total citations of 33 articles were 6 094 times, with a mean of 12.64 citations per article. These top-cited papers came from 11 countries, of which 12 articles came from the United States. University of Rostock led the list of classics with five papers. Harvard University and Massachusetts General Hospital ranked the second with four papers each. The 33 top-cited articles were published in 18 journals, predominantly Annals of Surgery and Hepatology, fol owed by Artificial Organs and Biotechnology and Bioengineering. Our bibliometric analysis provides a historical perspective on the progress of bioartificial liver research. Articles originating from outstanding institutions of the United States and published in high-impact journals are most likely to be cited.

Objective To evaluate the effect and mechanism of non-steroidal anti-flammatory drags(NSAIDs) on the colon cancer cell growth by using S-nitrosoglutathione(GSNO) which can produce nitric oxide.(Methods) Apoptosis of 3 colon cell lines were evaluated by cell growth curve and flow cytometry,the PGE_2 levels in cell culture supernatants were determined by competitive enzyme immunoassay method,and the(protein) expression of COX-1 and COX-2 were analyzed by Western blot.Results The production level of PGE_2 was increased with CSNO treated concentration and time.Using 500?mol/L CSNO treatment for 48h,the expression level of COX-1 and COX-2 protein increased.NASIDs can block the production of PGE_2 but had no effect on the inhibition of cell growth induced by GSNO.Conclusions GSNO can increase PGE_2(production) and induce COX-1 and COX-2 protein expression in a dose-and time-dependent manner.Higher concentrations of GSNO also can inhibite cell growth and induced apoptosis in all 3 cell lines.NSAIDs can block production of PEG2 but NSAIDs are no effect on cell growth.

Objective To explore causes leading to and the timing of liver retransplantation. Methods Among 164 cases of liver transplantation from Jul. 1999 to Dec. 2004, 6 cases underwent retransplantation with an incidence of 3. 65%. Causes included multiple intrahepatic bile duct stricture by ischemic reperfusion injury in 3 cases, hepatic artery stricture and thrombosis, hepatitis B recurrence, outflow obstruction of hepatic veins in one each. Results Clinical symptom improved in 4 cases, and failed to improve in 2 cases. Two cases suffered from intraabdominal bleeding, one biliary leak, one bacterial infection, two mold infection. Two patients died from bacterial and mold infection in four months. Conclusion Ischemic reperfusion injury is main cause resulting in intrahepatic bile duct stricture, liver retransplantation should be performed when the function of graft deteriorates significantly and conservative therapy fails.

OBJECTIVETo compare the applied value of the pressure aggravation test and breath aggravation test in the diagnosis of early acute appendicitis.

METHODSA total of 101 cases with epigastralgia, middle or upper abdomen pain, disease duration within 6 hours undergoing pressure aggravation test and breath aggravation test respectively in our hospital between October 2010 and December 2012 were prospectively enrolled. By comparing with the postoperative pathological diagnosis (early acute appendicitis and other abdominal pain), the sensitivity and specificity of these two tests were calculated. Through analyzing the receiver operating characteristic (ROC) curve, the diagnostic value of early acute appendicitis was evaluated.

RESULTSFifty-two cases of early acute appendicitis and 49 cases of other abdominal pain were diagnosed by postoperative pathologic results. The sensitivity and specificity of the pressure aggravation test were 87.5% and 72.1% and of the breath aggravation test were 53.8% and 83.7% respectively. The area under the ROC curve of the pressure aggravation test was 0.786 (95% CI: 0.693-0.878), similar to that of the breath aggravation test (0.688, 95% CI: 0.583-0.792).

CONCLUSIONThe pressure aggravation test has higher value to diagnose early acute appendicitis, while the breath aggravation test has better specificity.

Prepared from 15.3% N-acetylated chitosan (FNC), half N-acetylated chitosan (HNC) possesses a good solubility in a weak basic solution, guaranteeing the formation of microcapsules by the coacervating reaction between HNC and methacrylic acid (MAA)-hydroxyethyl methacrylate (HEMA)-methyl methacrylate (MMA) (MAA-HEMA-MMA) terpolymer under physiological conditions. When hepatocytes were encapsulated in such 3-dimensional microenvironment, as compared to monolayer culture, cell functions, including P450 activity, urea production and albumin release, were well supported. The prepared microcapsules have good mechanical stability and permeability.
Animals ; Capsules ; Cell Culture Techniques ; methods ; Cells, Cultured ; Chitosan ; chemistry ; pharmacology ; Hepatocytes ; cytology ; drug effects ; Male ; Methacrylates ; Methylmethacrylate ; Polymers ; Rats ; Rats, Wistar ; Tissue Engineering ; methods

In this study, the general toxicity tests including acute toxicity test, haemolysis test, MTT assay of Ti-Fe-Mo-Mn-Nb-Zr alloys were carried out. The morphology of these cells was also observed under phase-contrast microscope. By using X-ray photoelectron spectroscopy(XPS), the kind and mol% of element in surface film were studied. The kind and concentration of element in dipping fluid were investigated by ICP atomic emission spectrometry. The results showed the primary component is TiO2 in surface film. The dipping fluid of Ti-Fe-Mo-Mn-Nb-Zr alloys contains Fe 0.2-1.07 mg/l and Mn 0.16-0.5 mg/l; such dental materials are beneficial to health. No cytotoxic effect was disclosed by in vitro and in vivo tests. The level of cytotoxicity was grade 0 and 1; the haemolysis degree was 0.558%-0.642%, i.e. less than 5%. The cells growing in the extract showed normal morphology. These data indicate that Ti-Fe-Mo-Mn-Nb-Zr alloy, as a dental material, has good biocompatibility.
Animals ; Biocompatible Materials ; chemistry ; toxicity ; Dental Alloys ; toxicity ; Iron ; toxicity ; Male ; Manganese ; Mice ; Molybdenum ; toxicity ; Niobium ; toxicity ; Osmotic Fragility ; Rabbits ; Random Allocation ; Spectrometry, X-Ray Emission ; Titanium ; toxicity ; Zirconium ; toxicity