| As a substitute ,the cryopreserved conduit valved homograft has been used abroad in the clinical practice of the cardiovascular surgery . It is not only used for the replacement of the aortic valve , pulmonary artery valve and mitral valve ,but for the good material of the extra-cardiac conduit and mends in the treatment of the complex congenital heart disease .It has a lot of excellences ,such as large valve orifice , natural valve structure , excellent hemodynamic characteristic not easily to form thrombus , require no anticoagulation, not easily to be adhered by bacteria , low incidence of infective endocarditis of post-operation et al ,and especially its valve tissue has biological viability that it is not easily to degenerate , age and calcify .Therefore how to keep the viability of the conduit valved homograft as possible as can in the process of preparation is an important task. Tn this experiment ,through the observation to the difference of glucose utilization and the proportion of typan's dry of three methods of sterilization and cryopreservation ,discuss the mechanism of influence of sterilization and cryopreservation to the viability of the conduit valved homograft ,and seek a preparation method that has satisfying sterilization effect and minimal influence to the viability of the conduit valved homograft to keep its viability as possible as can .Material and MethodSelect 30 sheared conduit valved homografts ,include 15 valved aortas and 15 valved pulmonary arteries ,were randomly divided into 3 groups ,and each group had 10 homografts ,and germiculture was done both pre-sterilization andpost-sterilization .Each homograft was sterilized in RPMI1640 solution containing Cefoxtin 240mg/L, Lincomycin 120mg/L, Polymycin B 100mg/L, Vancomycin 50mg/L ,homografts in group A were sterilized under 37 for 24h , homografts in group B were sterilized under 37 for 6h , homografts in group C were sterilized under 4 for 24h .After sterilization the samples were obtained to examine the glucose utilization and the proportion of typan's dry .And the unsterilized tissue samples were used as control group .13conduit valved homografts were thawed ,and samples were obtained to compare the difference between pre-cryopreservation and post-cryopreservation in the glucose utilization and the proportion of typan's dry .Results(1)Culture result of 30 conduit valved homografts before sterilization: 8 were positive in group A ,6 were positive in group B, 6 were positive in group C, and the total positive rate was 66.7%. Cultured after sterilization ,none of the conduits was positive ,and the culture results of the 13 thawy conduits were all negative . (2) The glucose utilization of all experimental groups were all lower evidently than the control group(GroupA : 35.54 1.76 mg/dl 24h, GroupB : 39.44 1. 49 mg/dl 24h, Group C : 38.60 1.27 mg/dl -24h, The control group : 41.98 1.76 mg/dl -24h) , P<0.05. (3) The non-Typlan's dry rate of all experimental groups were all lower evidently than the c7%. The control group : 93.2%), P<0.05. (4) Among the experimental groups ,the glucose utilization of Group A (35.54 1.76 mg/dl 24h) was lower evi ontrol group(Group A : 79.7% , GroupB : 87.6%, Group C : 86. dently than Group B and C ( 39.44 1 .49 mg/dl 24h, 38.60 1 .27 mg/dl 24h ) , P<0.01 . But there was no evident difference between Group B and Group C, P >0.05. (5) Among the experimental groups ,the non-Typlan's dry rate of Group A ( 79.7% ) was lower evidently than Group B and C ( 87.6%, 86.7%), P<0.05. But there was no evident difference between Group B and Group C, P >0.05. (6) The viability of conduits would debase after cryopreservation, especially for those cryopreserved over 9 months. In this experiment, there was a conduit , cryopreserved over 15 months, its glucose utilization was lower than 16mg/dl 24h.CONCLUSION1. The antibiotics used in this experiment can obtain the satisfying sterilizing effect.2. The sterilizing process using antibiotics can damage th... |
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