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BACKGROUND:The principle of lyophilization is to sublimate the solvent of frozen materials in vacuum and retain the solute, thus making a pore structure. OBJECTIVE: To produce a chitosan tubular scaffold by lyophilization, and to test its physicochemical properties. METHODS: The chitosan tubular material was prepared by lyophilization method, folowed by gross observation and electron microscopic observation. The chitosan tubular material samples were placed into PBS solution and pure water for 50 days, respectively, and then immersed in trypsin liquid for 1 day folowed by embedded into the muscle and dorsal skin of neonatal Sprague-Dawley rats for 30 days. The degradation rate and porosity of the material were observed and calculated. The breaking strength and compressive strength of the material were determined both under drying and soaking conditions using tensile instrument and pressure meter, respectively. RESULTS AND CONCLUSION:The external form of the chitosan tubular material was normaly tubular. Under the electron microscope, it was composited by different size pores, and the pore size was 50-200μm. The degradation rates of the material were (5.33±0.12)% in PBS, (11.26±0.15) in water, 0.012% in the trypsin liquid and (35.2±3.7)in vivo. The porosity rate was (97.5±1.5)%. The breaking strength and compressive strength of the material was higher under the drying state than under the soaking state (P < 0.05). These findings indicate that the lyophilization method can produce the chitosan tubular material with good porosity rate and degradation rate as wel as good tensile ability and compressive capability.
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ObjectiveTo evaluate the efficacy of mini-incisional double-tsuge suture method with 0-0 absorbable polydioxanone-cord (PDS-Ⅱ)in repair of acute achilles tendon rupture.MethodsA total of 34 patients were subjected to acute closed achilles tendon ruptures,including 25 males and 9 females at a mean age of 32 years ( range,20-45 years).Injury causes included sports injuries in 27 patients,falling injuries in six and heavy object impingement injury in one.The time from injury to operation was average 3 days (range,1-6 days).All patients underwent minimally invasive repair with double-tsuge suture method by using PDS-Ⅱ.The ankle joint was fixed with short leg plaster cast at 30° plantar flexion position and the cast was removed six weeks later to take functional exercise.The patients could walk with full weight-bearing 8-10 weeks later and could gradually return to activity 3-4 months later.Results There was one patient with poor incision healing and one patient with reflex sympathetic dystrophy postoperatively.The rest patients had stage Ⅰ incision healing without skin adhesions.No complications such as infection,lower extremity deep venous thrombosis or sural nerve injury occurred postoperatively.All the patients received follow-up of 12-24 months (average 15 months),which showed no complications like tendon rerupture occurred.According to clinical evaluation criterion of Termann,the average score was 92 points (range,76-96 points).The result was excellent in 28 patients,good in five and fair in one,with excellence rate of 97％.ConclusionsSmall incisional double-tsuge suture method achieves low rate of complications and good outcomes for repairing acute achilles tendon rupture and is an ideal tendon surgery approach.
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BACKGROUND: Secretion of various neurotrophic factors by Schwann cells plays important roles in neural regeneration. However, the secretion capability is affected by many factors. To seek a feasible method for promoting nerve growth factor secretion by Schwann cells is a key of regeneraion following neurologic defect.OBJECTIVE: To explore the effects of methylprednisolone(solu-medrol) on the secreted function of Schwann cells of cultured rats.METHODS: Schwann cells were isolated and cultured by enzyme digestion method. Cell growth was observed under an inverted phase contrast microscope. Following passage, purity of some Schwann cells was identified using S-100 protein immunity. Other Schwann cells were regulated using cell counting plate into 1×10~9/L, and incubated in a 6-well culture plate (15 wells) for further incubation. Following 4 days of culture, different concentrations of solu-medrol (10~(-3), 10~(-4), 10~(-6), 10~(-8) mol/L) were administrated to the cell, while blank control group (1 well) was given no drug. 24, 48 and 72 hours after administration, reverse trancription-polymerase chain reaction (RT-PCR) was used in the detection of the levels of nerve growth factor mRNA.RESULTS AND CONCLUSION: Number of primarily cultured cells was significantly increased at day 7, and 80% cells were confluent. Subcultured cells were spindle-shaped, with 2 thin long processes, showing positive fluorescence staining. Fibroblasts were round or flat, showing negative reaction of fluorescence staining. Reserve transcription-polymerase chain reaction demonstrated that nerve growth factor number at 72 hours affected by 10~(-8) mol/L radiosone was increased compared with the blank control group and other concentrations and other time points (P < 0.05). Number of nerve growth factor was reduced following treatment of 10~(-3) mol/L radiosone compared with the blank control group and other concentrations (P < 0.05). These results suggested that high concentration of solu-medrol prohibits secreted function of Schwann's cells, but long time and low dosage solu-medrol promotes secreted function of Schwann's cells.
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Clinically,peripheral nerve injury is common,treatment is still a clinical problem.Because of the peripheral nerve's particular dissection and the function,repair of its damage is a complex process,meticulous microsurgical technique can be used to restore nerve continuity,but the restoration of nerve function is still not satisfactory.Recently,the domestic and foreign scholars has made effort and achieved some success,particularly,the allograft nerve transplant has applied in clinical.
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Objective To study the effects of CD2-associated protein (CD2AP) on podocyte adhesion and extension ability and to explore its possible mechanism. Methods Conditionally immortalized murine podocyte cell line was cultured in RPMI 1640 medium at 33℃permissive conditions. The podocytes were transfected with CD2AP small interfering RNA (siRNA) and serambing sequences labeled with fluorescein were taken as control. The transfected podocytes were trypsinized and seed into collagen IV coated plates. The relative cell adhesion and cell area were examined 90 min later. Apoptotic rates of CD2AP siRNA transfected podoeytes and different PAN concentrations incubated podoeytes were detected by flow cytometer. The distribution of F-actin was observed under laser scanning confoeal microscope. Nephrin protein expression and its phosphorylation level were examined by immunofluorescence and Western blot. Results The relative ceil adhesion of CD2AP siRNA transfected podocytes was apparently lower than that of control group[(41.72±6.07)% vs (64.46±8.53)%, P<0.05]. The cell area analysis had the similar result. The apoptotic rate of CD2AP siRNA transfected podocytes was significantly higher than that of the controls [(5.73±0.61)% vs (3.26±0.45)%, P<0.05]. 100 mg/L PAN could markedly induce podocytes to apoptosis and impair cell adhesion ability (P<0.05). Nevertheless, no significant difference was found in cell body spreading (P>0.05). The distribution of F-actin in CD2AP depletion podocytes was apparently altered. The expression of nephrin protein and its phosphorylation level was conspicuously descended to some degree (P<0.05). Conclusions CD2AP depletion facilitates podocyte apoptosis and impairs cell adhesion function. Cytoskeleton confusion and nephrin signaling weakness caused by CD2AP depletion may he partly responsible for the decline of cell adhesion and spreading.
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Objective To study the effect of overexpression of TRPC6 on Ang Ⅱ-induced apoptosis of mouse podocytes in vitro and to explore the possible mechanisms. Methods Mouse TRPC6 cDNA eukaryotie expression vector pEGFP-NI-mTRPC6 was transfected to conditionally immortalized routine podocyte cell line by liposome. The fluorescent microscopy was used to examine the expression of EGFP after 24 hours. The change of TRPC6 protein expression was observed by Western-blot. Podocytes were treated by different concentrations of Ang Ⅱ. The podocyte intracellular calcium concentration was measured with laser-scanning con_focal microscope. The expression of Bax and Bcl-2 mRNA was assessed by RT-PCR and the expression of Bax and Bcl-2 protein was measured by Western-blot. The apoptotic ratio of podocytes was monitored by flow cytometry and Hoechst staining. Results About 35% of the cells expressed EGFP. An up-regulation of protein expression of TRPC6 was detected in podocytes when transfected with pEGFP-N1-mTRPC6 (P<0.01). The overexpression of TRPC6 promoted the Ang Ⅱ-induced influx of extracellular calcium and elevated the expression of Bax but decreased the expression of Bcl-2 (P<0.01, P<0.05). The apoptotic ratio of podocyte was (2.50±0.72)% when treated by low-dose Ang Ⅱ (10-10 mol/L), and it was increased to (4.33±0.45)% when transfected with pEGFP-N1-mTRPC6 (P <0.05 ). Transfection with pEGFP-NI-mTRPC6 increased apoptosis rate from (15.46± 1.40)% to (18.33±0.87)%(P<0.01) by high-dose Ang Ⅱ (10-6 mol/L). Conclusion TRPC6 plays an important role in the Ang Ⅱ-induced apoptosis of podocytes by promoting the influx of extraeellular calcium, which leads to the apoptosis cascade initiation.