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Reactive oxygen is closely related to the occurrence and development of tumors. Manganese superoxide dismutase (MnSOD),as an antioxidant enzyme that scavenges superoxide anion in the mitochondrial matrix,plays an important role in maintai-ning mitochondrial redox homeostasis and protecting mitochondrial DNA. Many studies have discovered that MnSOD has different ex-pression levels in different tumors,and has both anti-cancer and cancer-promoting functions,but its functional conversion mecha-nism remains unclear. This article intends to investigate the role of MnSOD in tumorigenesis and development,and to review the main regulatory mechanisms of its expression level and activity.
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Objective To detect the physico-chemical properties , cytotoxicity and antimicrobial activity of dressings containing Ag +.Methods The morphology of this dressing was shown by the scanning electron microscope ( SEM ) .The cytotoxicity was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) method.Using the shake flask test method , the antibacterial effect of dressings was studied .Result There was no significant difference in the water vapor transmission rate between the dressings (P>0.05).Compared with the alginate calcium dressing ,silver ion dressings had a stronger swelling rate .A higher ion concentration would lead to a much larger swelling rate and slower degradation . A lower cytotoxicity was exhibited among the dressings .The silver ion dressing had stronger bacteriostasis to Gram-positive ( G+) and Gram-negative ( G-) bacteria than the alginate calcium dressing .Conclusion The experiment has proved that the silver ion dressing has stronger antibacterial activity and lower cytotoxicity , and it is more effective for wound surface healing, with a shortened treatment course .
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BACKGROUND:Intraarticular hyaluronic acid (HA)has been used as one common method in the treatment of osteoarthritis. But its application in treating Kashin-Beck disease (KBD) is generalizing. The effect of HA on chondrocyte metabolism in KBD patients remains unclear.OBJECTIVE:To investigate the effects of HA on the synthesis of collagen Ⅱ and aggrecan in KBD chondrocytes cultured in vitro to understand its clinical treatment for KBD.DESIGN,TIME AND SETTING:Comparative observation. The experiment was performed in the Laboratory Center of Biomedicine and Endemic Disease Laboratory of College of Medicine,Xi'an Jiaotong University from September 2006 to January 2009.MATERIALS:Samples of KBD were from cartilage and corpus liberum excised from 6 KBD patients undergoing knee joint operation,and normal samples of fresh knee cartilages were provided by 6 people undergoing amputation or death by accident METHODS:Chondrocytes of KBD and normal control were separated and cultured in vitro. Varying dosages of HA (100,500 gm/L) were administered to normal and KBD chondrocytes cultured in vitro for 6 days. Negative control was not treated with HA.MAIN OUTCOME MEASURES:Effects of HA on collagen Ⅱ and aggrecan mRNA expression in KBD patients and normal people by RT-PCR.RESULTS:Compared with normal control group,the mRNA level of collagen Ⅱ and aggrecan were lower in KBD (P＜0.05).After administration of HA (100,500 mg/L) the mRNA level of collagen Ⅱ and aggrecan were significantly increased,and the effects of 500 mg/L was more significant.CONCLUSION:HA can increase the collagen Ⅱ and aggrecan mRNA level of KBD chondrocytes cultured in vitro. In particular,500 mg/L HA significantly promoted chondrocyte metabolism compared with 100 mg/L HA.
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Water-soluble carboxymethyl chitosan was prepared from dried shrimp shells. The intrinsic viscosities of its samples were measured to evaluate the stability of carboxymethyl chitosan. The influential factors of stability, such as heat, pH, ionic strength, ultraviolet radiation, and sterilization were studied. The results demonstrate that the intrinsic viscosities of water-soluble chitosan will be influenced, to a certain extent, by the change of pH and ionic strength. Ultraviolet radiation and sterilized processes not only exept influence on the degradation of chitosan, but also have prominent effects on the molecular structure of it. Besides, temperature will also affect the speed of degradation, and chitosan can be stored at a temperature as low as 2 degrees C-8 degrees C.
Subject(s)
Chitosan , Chemistry , Drug Stability , Hydrogen-Ion Concentration , Solubility , TemperatureABSTRACT
As a kind of biomaterial, carboxymethyl chitosan (CMC) has excellent biodegradable and bioacceptable capabilities using. This study was aimed to probe into the feasibility of CMC to prepare the implantable sustained release Ciprofloxacin Hydrochloride (CPX) microspheres(MS), and to go further into the pharmaceutic technology, the morphology and the characteristics of in vitro release of the microspheres. First, we prepared the microspheres by emulsification and cross-linking technology. Then, scanning electron microscopy (SEM), infrared spectrum (IR) and differential thermal analysis (DTA) were used to detect the structure and morphology of the MS. The in vitro release of CPX/CMC-MS and the CPX content of the MS were detected through continuous-flow releasing system. We found that the structure and morphology of the MS were affected by the conditions of preparation such as emulsification and cross-linking temperature, ionic strength and stirring speed, that the releasing time of CPX was more than 7 days, and that the releasing behaviors of the microspheres conformed to the Higuchi model. So we drew the conclusions that CMC could be used as a kind of absorbable and implantable adjuvant for sustained release, the technology of emulsification and cross-linking was proved to be feasible, stable and simple.
Subject(s)
Humans , Absorbable Implants , Biocompatible Materials , Biodegradation, Environmental , Chitin , Pharmacokinetics , Chitosan , Ciprofloxacin , Pharmacokinetics , Cross-Linking Reagents , Delayed-Action Preparations , Drug Carriers , MicrospheresABSTRACT
Objective:To study the hemostatic and adhesion-prevention properties of gelatin-chitosan crosslinked film after craniotomy. Methods: Gelatin-chitosan crosslinked film was prepared by casting the mixed solution of dialyzed chitosan and gelatin after crosslinking with glutaraldehyde in freeze dryer. Bleeding time was recorded for bilateral back incisions (5 incisions on each side) in 4 New Zealand white rabbits. Incision on one side was treated with gelatin-chitosan crosslinked film, and on the other was treated with gauze. Hemoglobin amount in films or gauzes was measured to determine the hemostatic effect after bleeding. Bilateral craniotomies were performed at calvaria in 16 adult rabbits. A piece of gelatin-chitosan crosslinked film was put in one randomized side and the other side served as a control. The scar formation was evaluated grossly and histologically on week 2,4,8,12. Results:Bleeding time and hemoglobin amounts in gelatin-chitosan crosslinked film group were superior to those in gauze group(P