Objective:To explore the consistency of MRI fast field echo resembling a CT using restricted echo-spacing (FRACTURE) and CT in the evaluation of knee and ankle bone changes.Methods:From November 2020 to November 2021, seventeen patients who underwent CT and MRI FRACTURE examinations of knee joint or ankle joint in the First Affiliated Hospital of Dalian Medical University were retrospectively collected, including 14 patients with knee joint examinations and 3 patients with ankle joint examinations. According to the number of joint components, 80 components were included, including 14 for femur and patella, 17 for tibia and fibula, and 3 for talus, scaphoid, medial cuneiform, medial cuneiform, lateral cuneiform and calcaneus, respectively. The fracture, hyperosteogeny, and bone destruction of the joint bones were evaluated by two observers using CT and FRACTURE images, respectively. Kappa test was used to analyze the consistency of CT and FRACTURE images between observers in the evaluation of joint bone lesions.Results:The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by CT and FRACTURE images were 0.925 (0.823-1.027), 0.905 (0.799-1.011) and 0.895(0.752-1.038) respectively for observer 1, and were 0.963 (0.892-1.034), 0.933 (0.843-1.023) and 0.886 (0.731-1.041) respectively for observer 2. The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by observers 1 and 2 via CT images were 1.000 (1.000-1.000), 0.937(0.851-1.023) and 0.945 (0.839-1.051) respectively, and that by FRACTURE images were 0.962 (0.888-1.036), 0.966 (0.899-1.033) and 0.836 (0.656-1.016) respectively.Conclusion:For the evaluation of fracture, hyperosteogeny, and bone destruction of knee joint and ankle joint, MRI FRACTURE sequence is highly consistent with CT.

Objective Interleukin 6(IL-6)is an important cytokine featuring pleiotropic activity in the cardiac microenviron-ment and improves cardiomyocyte regeneration to favor cardiac repair after injury.Thereby this study aimed to investigate the effects of IL-6 on murine embryonic cardiomyocyte proliferation and unveil the possible developmental changes.Methods Single cardiomyocyte was obtained from mouse through enzyme dissociation at the early embryonic developmental stage(EDS)and late embryonic developmental stage(LDS).The cells were cultured for 24 h in 20％DMEM and then treated with 10 ng/mL IL-6 or 50 ng/mL IL-6 for 24 h.The effect of IL-6 on cardiomyocyte proliferation was comprehensively studied by tracing BrdU+α-acti-nin+nuclei and BrdU+α-actinin+mononuclear cardiomyocyte with immunofluorescence staining.Western blot was performed to unveil the changes in phosphorylation levels of the key proteins under IL-6 treatments.Results The 10 ng/mL IL-6 did not change the proliferation capacity of EDS myocardium,but significantly promoted the proliferation capacity of LDS myocardi-um.The 50 ng/mL IL-6 significantly inhibited the proportion of EDS BrdU+α-actinin+monocytes,and increased the proportion of LDS BrdU+α-actinin+nuclei and BrdU+α-actinin+monocytes.This might be related to the various effects of IL-6 at differ-ent concentrations on signal transduction pathways of EDS and LDS cardiomyocytes:10 ng/mL IL-6 and 50 ng/mL IL-6 inhibi-ted the phosphorylation of Akt in EDS cardiomyocytes,and had no significant effect on the phosphorylation of STAT3 and ERK.In LDS,10 ng/mL IL-6 and 50 ng/mL IL-6 inhibited phosphorylation of Akt and increased the phosphorylation of STAT3,but had no significant effect on the phosphorylation of ERK.Finally,the basic phosphorylation states of these three proteins were detected and the total protein amount and phosphorylation levels of STAT3,Akt and ERK showed a development-dependent decline.Conclusion IL-6 influenced the fetal cardiomyocyte proliferation in a developmental-and dose-dependent manner.It might be related to the developmental changes in the basic status of the target signaling pathways.These observa-tions provided new knowledge of cardiac proliferation and might propose new clues for the microenvironment in cell therapy.