Objective To investigate the relationship between V-raf murine sarcoma viral oncogene homolog B1 (BRAF)v600E mutation and radioactive iodine (RAI) uptake in distant metastases from papillary thyroid cancer(PTC).Methods From January 2011 to December 2012,40 PTC patients (21 males,19 females,average age 39.8 years) with distant metastases were recruited and divided into mutation group and wild group according to the BRAFv600E mutation in primary lesions.The clinical,pathological and serological differences were compared between the two groups.The relationship between BRAFv600E mutation and RAI uptake capability in distant metastases from PTC,as well as its relationship with Tg change after 131I treatment were investigated.Statistical analysis was performed with two-sample t test,x2 test or Fisher exact test.Results The BRAFv600E mutation rate was 30.0％ (12/40) in patients with metastases from PTC.There was no significant difference in clinical,pathological and serological features between mutation group (n =12) and wild group (n=28; t:from-0.533 to 1.728,x2:from-1.951 to 1.088,all P＞0.05).Twelve PTC patients had no RAI uptake in the distant metastases,of which 10 belonged to mutation group (83.3％,10/12) and 2 belonged to wild group (7.1％,2/28; x2=19.734,P＜0.05).BRAFv600E mutation group was more likely to have no RAI uptake in the distant metastases.Tg change after 131I treatment in 30 patients were analyzed.In the wild group,Tg level decreased in 66.7％ (14/21) patients,stabilized in 19.0％ (4/21)and increased in 14.3％ (3/21)patients.While there was no decrease of Tg in the mutation group (0/9).Two patients had increased Tg level and 7 patients (with no RAI uptake) kept stable in mutation group.Conclusions Due to poor RAI uptake capability in PTC patients with BRAFv600E mutation,both primary and metastatic sites may have poor response to 131I treatment.Molecular detection of BRAFv600E mutation might be helpful for choosing PTC with distant metastases and predicting the effect of 131 I treatment.

Objective:To evaluate the acute effects of different foot-strike patterns of running on knee cartilage in amateur marathon runners using the T 2* mapping technique. Methods:From November 2021 to February 2022, 29 amateur marathon runners were recruited in Hangzhou. The gait analysis was performed to determine their landing patterns, then the runners were divided into the fore-foot strike (FFS) group (11 cases) and the rear-foot strike (RFS) group (18 cases). The MRI of the knee joint of the dominant leg was performed before and 30 min after running, and the volume, thickness, and T 2* value of each division of knee cartilage were measured. Independent samples t-tests were used to compare the differences in baseline data before running between the groups, and paired samples t-tests were used to compare the differences before and after running within the groups. Results:The difference in knee cartilage volume and thickness between the FFS and RFS groups before running was not statistically significant ( P>0.05), and the T 2* value of the femur medial posterior in the RFS group was higher than that of the FFS group ( t=-2.47, P=0.020). Compared with pre-running, cartilage thickness of the tibia lateral posterior decreased in the FFS group after running ( t=-2.96, P=0.016), and cartilage thickness of the tibia lateral posterior and patella lateral central decreased in the RFS group ( t=-3.25, -3.02, P=0.004, 0.007). Cartilage volume of the tibia lateral posterior decreased in the FFS group after running ( t=-2.58, P=0.030), and the cartilage volume of the patella lateral central decreased in the RFS group ( t=-2.74, P=0.013). The differences in T 2* values of cartilage in each region before and after running were not statistically significant in the FFS group ( P>0.05), whereas in the RFS group, the cartilage T 2* values in the femur medial posterior, femoral trochanter central, femoral trochanter lateral, femur lateral central, tibia lateral anterior, tibia medial posterior, tibia medial central, and tibia medial anterior decreased ( P<0.05). Conclusions:After running, FFS showed changes in morphology and biochemical composition only in some subregions of tibial cartilage, whereas most of the femoral cartilage, patellar cartilage, and tibial cartilage regions were altered by RFS. The RFS pattern introduces greater acute changes in cartilage in the knee joint.