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Objective To classify traumatic triangular fibrocartilage complex(TFCC)injury based on 3.0T MR.Methods A total of 46 patients with definite history of wrist trauma admitted were collected.All patients underwent MRI scanning within 3 days after trauma,and the MRI findings were classified as follows according to the Palmer classification criteria:the focal structures of triangular fibro-cartilage(articular disc)(TFC)injury,the horizontal of the articular disc tear,injuries of ulnar styloid attachment and ulnar fovea attach-ment in TFC,ulnolunate and ulnotriquetral ligaments injuries,injury of the radial sigmoid notch junction,meniscal homologous inju-ry.The presence of TFCC injury was eventually confirmed by surgery in all patients.Results Of 46 patients,38 patients could be classified by Palmer,and there were 10 cases with type ⅠA,23 cases with type ⅠB,3 cases with type ⅠC and 2 cases with type ⅠD.A total of 8 patients were not suitable for Palmer type,and there were 3 patients with horizontal tears in the articular disc and 5 patients with meniscus homologous injuries.Conclusion The 3.0T MR can not only show various subtypes of Palmer classification,but also refine and supplement the classification based on the original classification,such as the injuries of ulnar styloid attachment and ulnar fovea attachment at the ulnar end of the articular disc,horizontal tear of the articular disc,meniscus homologous injury,etc.
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OBJECTIVE: To study the effect of sub-chronic aluminum exposure on synaptic plasticity in the hippocampus of rats and to explore the mechanism of phosphatidylinositol 3 kinase(PI3 K)/protein kinase B(AKT)/rapamycin target protein(mTOR) signaling pathway. METHODS: Specific pathogen free adult healthy male SD rats were randomly divided into control group and low-, medium-and high-dose groups based on body weight, with 10 rats in each group. Rats were treated with maltol aluminum solution at the concentrations of 0, 10, 20 and 40 μmol/kg body weight by intraperitoneal injection, 5 days per week for 3 months. After the exposure, rats were weighed. Morris water maze was used to test the learning and memory ability, and the two-electrode binding technique was used to record the long-term potentiation(LTP) amplitude in the hippocampus CA1 area of rats. The protein expression of PI3 K, AKT and mTOR in rat hippocampus tissues was detected by Western blot. RESULTS: After the exposure, the body weights of rats in the medium-and high-dose groups were lower than that of the control group(P<0.05). The results of the positioning navigation experiment showed that the escape latencies of the rats in the medium-and high-dose groups were shorter than that in the control group during the 2 nd to 4 th days of the experiment(P<0.05). The results of space exploration experiments showed that there was no statistical difference on the target quadrant retention time and the number of crossing the platform among the 4 groups(P>0.05). At 1, 30, and 60 min after high-frequency stimulation, the LTP amplitudes in the hippocampus CA1 area of the aluminum-treated groups were lower than that of the control group at the same time point(P<0.05), and the LTP amplitudes of hippocampus CA1 area of rats decreased with the increase of maltol aluminum exposure dose(P<0.01). The relative expression of PI3 K, AKT and mTOR protein in the hippocampus tissues of the aluminum-treated groups was lower than that of the control group(P<0.05), and the relative expression of the above three proteins decreased with the increase of the maltol aluminum exposure dose(P <0.01). CONCLUSION: Sub-chronic aluminum exposure could lead to dose-dependent inhibition of hippocampus synaptic plasticity in rats, thereby impairing the spatial learning ability of rats. This process may be related to inhibition of PI3 K/AKT/mTOR signaling pathway by aluminum.