ABSTRACT
【Objective】 To study the technology of separating and purifying C1 esterase inhibitor (C1-INH) by using the waste washing liquid as raw materia during the preparation of human prothrombin complex (PCC) l. 【Methods】 C1-INH was isolated and purified by a two-step method of polyethylene glycol (PEG) 4000 precipitation and cation chromatography. The pH of raw materials and the concentration of PEG4000 were adjusted to investigate the optimal conditions of PEG4000 precipitation method. After PEG was precipitated and centrifuged, the supernatant is treated as the loading solution for cation exchange chromatography, using Fractogel EMD SE HiCap(M) gel and CM Sepharose FF gel for ion exchange chromatography. The most suitable gel and separation conditions were selected by comparing the C1-INH antigen yield, activity yield and specific activity. 【Results】 Under the condition of pH 6.1, when the mass fraction of PEG4000 was 14%, the recovery rate of C1 esterase inhibitor was close to 70%, and the removal rate of ceruloplasmin was more than 95% after stirring for 10 minutes. As fractogel EMD SE HiCap(M) gel was used for cation exchange chromatography, when the eluent salt concentration was 0.25 M sodium chloride, the activity yield of C1 esterase inhibitor was greater than 80%, and the specific activity was greater than 5 IU/mg. 【Conclusions】 Using the waste washing liquid as the raw material during the preparation of PCC, the C1 esterase inhibitor with high specific activity can be prepared through PEG precipitation and purification by Fractogel EMD SE HiCap(M) ion exchange chromatography.
ABSTRACT
Objective:To assess the clinical effects of carbon fiber reinforcement on the“All-on-Four”provisional prostheses.Methods:Provisional prostheses were divided into control group and carbon fiber reinforcing group according to whether carbon fiber reinforcement was used in the provisional prostheses base resin.In our study,a total of 60 patients (32 males and 28 females)with 71 provisional prostheses (28 maxilla and 43 mandible)were enrolled between April 2008 and December 201 2 for control group;a total of 23 patients (1 3 males and 1 0 females)with 28 provisional prostheses (9 maxillas and 1 9 mandi-bles)were enrolled between January 201 3 and March 201 4 for carbon fiber reinforcing group.The infor-mation of provisional prostheses in the patients was recorded according to preoperative examination.We used the date of definitive prosthesis restoration as the cut-off point,observing whether fracture occurred on the provisional prostheses in the two groups.Additionally we observed whether fiber exposure occurred on the tissue surface of the provisional prostheses and caused mucosal irritation.The interface between the denture base resin and the fibers was examined using scanning electron microscopy (SEM).Results:The age [(57.3 ±1 0.1 )years vs.(55.1 ±1 1 .4)years],gender (32 males and 28 females vs.1 3 males and 1 0 females),maxilla and mandible distributions (28 maxillas and 43 mandibles vs.9 maxillas and 1 9 mandibles),the number of extraction jaws (46 vs.23 ),the average using time [(7 .8 ±1 .3 ) months vs.(7 .5 ±1 .1 )months],and the opposing dentition distributions of provisional prostheses of the patients showed no significant differences between the control and reinforcing groups.There were 21 (29 .6%)fractures that occurred on the 71 provisional prostheses in the control group;there was no frac-ture that occurred on the 28 provisional prosthesesin the carbon fiber reinforcing group.The fracture rate of the carbon fiber reinforcing group was significantly lower than that of the control group (P=0.001 ). No carbon fiber exposure and mucosal irritation were observed from clinical examination.SEM revealed relatively continuous contact between the fiber and acrylic resin,and the resin particles adhered on the surface of the carbon fibers.Conclusion:The addition of carbon fibers between abutments placed on“All-on-Four”provisional fixed denture base resin may be clinically effective in preventing “All-on-Four”denture fracture and can provide several advantages for clinical use.
ABSTRACT
<p><b>OBJECTIVE</b>To study the radiobiological characteristics of a HepG2 cell line with mitochondrial DNA (mtDNA) deletion.</p><p><b>METHODS</b>HepG2 cells were cultured in a medium containing ethidium bromide, acetylformic acid and uracil. The HepG2 cell line with mtDNA deletion (ρ(0)HepG2 cells) were acquired after 30 subcultures by limited dilution cloning. The cell survival was then observed in the absence of acetylformic acid and uracil, and the total mtDNA deletion in the cells was confirmed by PCR. The radiosensitivity of HepG2 and ρ(0)HepG2 cells was evaluated by exposure to gradient doses of 6 MV X ray irradiation. The cell apoptosis was assessed following a 2 Gy X-ray exposure with Hochest33342 staining, and the invasiveness of ρ(0)HepG2 cells was measured by Transwell assay.</p><p><b>RESULTS</b>HepG2 cells could survive 30 subcultures in the presence of ethidium bromide, and massive cell death occurred after removal of acetylformic acid and uracil from the medium. PCR confirmed total mtDNA deletion from ρ(0)HepG2 cells, whose α/β value was significantly lower than that of HepG2 cells. ρ(0)Hep-G2 cells showed an obviously lowered cell apoptosis rate following X-ray exposure with enhanced cell invasiveness.</p><p><b>CONCLUSION</b>HepG2 cells can be induced by ethidium bromide into ρ(0)HepG2 cells with an increased radiation resistance, anti-apoptosis ability and cell invasiveness.</p>