Objective To study the development of a physiologic fixation method and investigate the effect of physiologic fixation method on porcine aortic root and aortic valve leaflets. Methods Physiological fixer of aortic root was manufactured in a factory. The fixers with different diameter were made of organic glass. Porcine aortic root with ascending aorta and anterior leaflet of mitral valve and partial ventricular septum were dissected out from the fresh heart. The roots were attached to appropriately sized inflow and outflow spigots. Physiologic fixation was utilized to maintain aortic root and leaflets natural anatomical shape, the aortic root was pressurized to the inflow and outflow portions simultaneously, and the leaflets floated freely at zero-pressure differential with in the pressurized root. Results The process of physiologic fixation retained the properties of a native valve. The leaflets were much softer and extensible than those from valves fixed under low pressure. The results of pulsatile flow testing indicated that the effective orifice areas of predilation at 80mmHg were significantly greater than those of predilation at 40 mmHg（P〈0.05）, while mean pressure differences were found to be lower comparatively（P〈0.05）. This difference translates into a mode of valve function that more closely approximates that of the native aortic valve. Conclusion Physiologic fixation process retains the valve＇s natural anatomical shape as well as the underlying structure of the leaflets, providing improved flow characteristics.
Objective To compare the characteristics of gelatin microspheres crossl inked by glutaraldehyde (GA) or geni pin (GP). Methods Gelatin microspheres, prepared by the improved emulsified cold-condensation method, were crossl inked by GP and GA, respectively. After being dispersed in PBS, two kinds of microspheres with 60% degree of cross l inking were compared in terms of morphology, swell ing and degrading properties. rhBMP-2 were loaded into the GP and GAmicrospheres, and the encapsulation rate, drug loading and releasing capacity were measured; 100%, 50% and 25% leaching l iquid of GP and GA microspheres were respectively cultured with rat osteoblast (DMEM group as the control), and cell prol iferation was measured by MTT method to grade the cell cytotoxicity. Results GP and GA microspheres were both spherical with the diameters of (78 ± 18) μm and (65 ± 10) μm, and there were no difference between both microspheres in drug loading and encapsulation rate. But, GP microspheres, with long degrading period (28 days) compared to GA microspheres (21 days), had better dispersibil ity, and swell ing rate (89.0% ± 4.8%), the percentage of cumulative drug releasing at 10 days (78.80% ± 4.96%) were both lower than GA microsphere (118.0% ± 7.6%, 90.50% ± 5.12%). The percentages of drug loading of GP and GA were (921 ± 73) and (965 ± 62) ng/g, and the encapsulation rates were 88.5% ± 2.1% and 89.7% ± 1.8%; showing no significant difference (P gt; 0.05). The cell cytotoxicity of 100%, 50% and 25% leaching l iquid of GP microspheres was all at the level I, but leaching l iquid of GA microspheres with corresponding concentration were at the levels of III, III and II. Conclusion GP crossl inked gelatin microspheres are superior to GA crossl inked gelatin microspheres and can be widely used in tissue engineering field.
ObjectiveTo compare the disinfection effect of peracetic acid versus glutaraldehyde in disinfection of flexible endoscope, and provide suggestions for choosing endoscopic disinfectant.MethodsWe searched literatures in PubMed, Embase, Cochrane Central Library, China National Knowledge Infrastructure, Wanfang database and VIP database, with the retrieval time from the establishment of each database to July 2017, screening and comparing the disinfection qualification rate of peroxyacetic acid versus glutaraldehyde in immersion disinfection of flexible endoscope. The number of flexible endoscopies after disinfection was the main effect index, and a fixed effect model analysis was performed.ResultsSix comparative studies were enrolled in this Meta-analysis, with a total of 786 flexible endoscopes. The result of Meta-analysis showed that the qualification rate of disinfection of peracetic acid was higher than that of glutaraldehyde with the same disinfection time [relative risk=1.09, 95% confidence interval (1.06, 1.13), P<0.000 01].ConclusionThe disinfection effect of peroxyacetic acid immersion method is better than that of glutaraldehyde.