BACKGROUND:Primates are considered to be the most appropriate animal model of lumbar intervertebraldisc degeneration, but the disc degenerated characteristics of monkeys were rarely reported. OBJECTIVE:To verify the degenerated regularity and characteristics of lumbar intervertebral disks in rhesus monkeys with magnetic resonance T2 mapping and T1ρimaging technology. METHODS:The sagittal lumbar intervertebral disc magnetic resonance T2 weighted imaging,T2 weighted mapping imaging and T1ρweighted imaging of 63 adult rhesus monkeys were acquired on 1.5T magnetic resonance equipment. The T2-map value and T1ρvalue of lumbar intervertebral disc regions of interest were calculated on the post-processing workstation. RESULTS AND CONCLUSION:(1) This study obtained 425 better magnetic resonance images of lumbar intervertebral disks in adult rhesus monkeys. T2-map value and T1ρvalue of nucleus pulposus were most consistent by different persons, and the Kappa coefficient was more than 0.93. (2) The T2-map value and T1ρvalue of nucleus pulposus were both negatively correlated significantly with Pfirrmann grades (r=-0.842, P<0.01;r=-0.896, P<0.01). The T1ρvalue and T2-map value of nucleus pulposus were significantly statistical y different between Pfirrmann grades I-IV (P<0.001, P<0.001). The T1ρvalue of nucleus pulposus was negatively correlated significantly with Pfirrmann grade II-III (r=-0.517, P<0.01) and Pfirrmann grade IV-V (r=-0.499, P<0.01). The T2-map value of nucleus pulposus was also negatively correlated significantly with Pfirrmann grade II-III (r=-0.617, P<0.01) and Pfirrmann grade IV-V (r=-0.652, P<0.01). (3) The T2-map value of L1-2 and L2-3 segments nucleus pulposus were significantly lower than that in L6-7 and L7-S1 segments (P<0.05). (4) There were significant differences in age among the T1ρvalue and T2-map value of nucleus pulposus (r=-0.702, P<0.001, r=-0.730, P<0.001). (5) It is concluded that magnetic resonance T2 mapping and T1ρimaging technology can objectively and sensitively assess the degenerated process of nucleus pulposus in rhesus monkeys. The degeneration in upper lumbar segments (L1-2 and L2-3) was earlier and more severe than that in lower lumbar segments (L6-7 and L7-S1) in rhesus monkeys. Age is one of the most important factors in lumbar intervertebral disc degeneration of adult rhesus monkeys.

Objective To evaluate the short-term prediction of high-sensitivity cardiac troponin T (hs-cTnT) and other cardiovascular risk biomarkers in patients undergoing maintenance hemodialysis (MHD).Methods We conducted a cohort survey in 296 consecutive MHD patients whose clinical data were retrospectively analyzed.Before MHD,hs-cTnT and other relative cardiovascular biomarkers were detected.The end point (all-cause death) and time of occurring were recorded in the next 13 months.The differences between survival and all-cause death were analyzed by t-test,Mann-Whitney test and x2 test.The best two percentile cutoff point was calculated by X-tile and the survival rate was calculated by Kaplan-Meier Logistic regression analysis was applied to analyze the odd ratio between high risk and non-high risk hs-cTnT group.Non-high risk group was divided into intermediate risk and low risk group based on the 99th percentile of hs-cTnT in healthy population,to further evaluate its short-term prediction value for MHD patients.The short-term significance of hs-cTnT was proved to be independently associated with all-cause death by Logistic regression analysis.Results The mean value of serum hs-cTnT in survival group was 0.05 (0.03～0.07) ng/mL,while in the death group it was 0.07 (0.04～0.14) ng/mL,which had statistical significance (P =0.027).The best two percentile cutoff of hs-cTnT in MHD patients was 0.1 ng/mL.The survival rate in high risk group (hs-cTnT＞0.1 ng/mL) is lower than it in non-high risk group (hs-cTnT≤0.1 ng/mL) (76.67％ vs.96.62％,P ＜0.05).The odd ratios for high risk group and non-high risk group was 7.288 (P＜ 0.001).Moreover,further grouping the non-high risk group by hs-cTnT =0.014 ng/mL,intermediate risk group (hs-cTnT＞0.014 ng/mL) group has lower survival rate than low risk group (hs-cTnT≤0.014ng/mL),while there wasn't any death case occurred in the low risk group.Conclusions Hs-cTnT is an independent risk factor to all-cause death.Thus hs-cTnT can be a strong indicator of short-term prediction and prognostic evaluation.