Objective To prospectively evaluate changes in T2 relaxation times in the meniscus with warm-up excise using MRI in healthy knees,and explore the feasibility of evaluating the morphological changes of meniscus after acute warming-up by T2 time response.Methods A total of 40 healthy adult volunteers were enrolled,which included 15 males and 25 females;aged 22-30 years old with mean age of 26.32 ± 2.1.T2 mapping sequential imaging was performed to measure the T2 time of medial and lateral anterior,body,posterior before and after warm-up exercise.A paired Student's t test was used to determine the effects of warm-up exercise on T2 times.Results All volunteers showed a significant increase in T2 values after warm-up exercise in all meniscus compartments (P =0.000),which may indicate changes in the biochemical composition of meniscal tissue.The lateral body compartment experienced more increment than medial anterior (P ＜ 0.05),medial posterior (P ＜ 0.05) and lateral posterior parts (P ＜ 0.05) after warm-up exercise.Conclusion Longer T2 values after warm-up exercise suggest increment in the water content of knee meniscus,which may indicate improvements in the physiological activity and protection of meniscus.T2 values in menisci have the potential to be used as biomarkers for identifying meniscus changes after exercise.

Objective:To explore the long-term preservation value and repair effect of normothermic machine perfusion (NMP) on clinically discarded kidneys.Methods:A case of clinical discarded donor kidney was collected, and NMP was carried out in vitro for 9 hours with recovered blood. The dynamic changes of renal appearance, blood gas and biochemistry analysis of perfusate and renal pathology were recorded. Results:In the second to fifth hour of NMP, the appearance of renal was pink and ex vivo normothermic perfusion assessment score (EVNP) was grade Ⅰ. While, the sixth hour and beyond of NMP, the appearance of kidney turned to dark red and EVNP was grade Ⅲ. The renal perfusion blood flow maintained above 150 ml/min in the first 6 hours and decreased significantly after that, and at the end, was only 50 ml/min. During the whole process of perfusion, urine output was maintained at about 100 ml/h. PO 2 remained above 100 mmHg in the first 5 hours of perfusion and from the 6th hour, was lower than 80 mmHg and continued to decline, and was close to 0 at the end of perfusion. The results showed that although the K + concentration changes in blood and urine in the first 5 hours of NMP had a good consistency, the lactic acid level had been rising. In addition, there was no significant change in the histopathology at the fourth hour of perfusion compared with that before zero-point puncture, and the fibrinous thrombus in glomeruli was improved compared with that before perfusion. However, at the sixth hour after perfusion and before the end of perfusion, the pathological changes of renal tissue were significantly worse. There were a large of thrombosis in glomerular blood vessels, renal tubular atrophy and acute tubular necrosis. Conclusions:NMP can realize the evaluation of extended criteria donors before transplantation, and it proves the feasibility and repair potential of NMP in kidney to a certain extent. At the same time, NMP also provides a new way to expand the source of donor kidney and to pre-treat organ in vitro.