Comparison Thigh Skeletal Muscles between Snowboarding Halfpipe Athletes and Healthy Volunteers Using Quantitative Multi-Parameter Magnetic Resonance Imaging at Rest.

BACKGROUND: Magnetic resonance (MR) imaging provides a unique, noninvasive diagnostic platform to quantify the physiological and biochemical variables of skeletal muscle at rest. This study was to investigate the difference in thigh skeletal muscles between snowboarding halfpipe athletes and healthy volunteers via multiparametric MR imaging. METHODS: A comparative study was conducted between 12 healthy volunteers and 14 snowboarding halfpipe athletes. MR scanning targeted the left leg at the level of the proximal thigh on a 3.0T MR system. The measured parameters compared between the two groups included T1, T2, T2* relaxation times, fat fraction (FF), and cross-sectional area (CSA) of the quadriceps femoris and the hamstring muscles. Statistical analysis was carried out using independent sample t-test. Interrater reliability was also assessed with intraclass correlation coefficients (ICCs). RESULTS: It was statistically equivalent between two groups in age, body mass index, thigh circumference, calf circumference, systolic blood pressure, and resting heart rate (all P > 0.05). However, the T1 and T2 values of the hamstring muscles in the athlete group were found to be significantly shorter than those in control group (T1: 1063.3 ± 24.1 ms vs. 1112.0 ± 38.2 ms in biceps femoris, 1050.4 ± 31.2 ms vs. 1095.0 ± 39.5 ms in semitendinosus, 1053.1 ± 31.7 ms vs. 1118.4 ± 40.0 ms in semimembranosus, respectively; T2: 33.4 ± 0.7 ms vs. 36.1 ± 1.9 ms in biceps femoris, 34.6 ± 2.0 ms vs. 37.0 ± 1.9 ms in semitendinosus, 36.9 ± 1.5 ms vs. 38.9 ± 2.4 ms in semimembranosus, respectively; all P < 0.05) although T2* relaxation time was detected with no significant difference. The FF of the hamstring muscles was obviously less than the control group (5.5 ± 1.9% vs. 10.7 ± 4.7%, P < 0.001). In addition, the quadriceps' CSA in the athlete group was substantially larger than the control group (8039.0 ± 1072.3 vs. 6258.2 ± 852.0 mm2, P < 0.001). Interrater reliability was excellent (ICC: 0.758-0.994). CONCLUSION: Multiple MR imaging parameters indicated significant differences between snowboarding halfpipe athletes and healthy volunteers in the thigh skeletal muscles.

[A case-control study on the risk factors for attempted suicide in patients with major depression].

OBJECTIVE: To understand the environmental risk factors on attempted suicide in patients with major depression, and to study the interaction between factors as single nucleotide polymorphism(SNP) of TPH2 gene rs7305115 associated to attempted suicide in major depression. METHODS: Paired case-control study on 215 suicide attempters with major depression (92 male, 123 female) and molecular biological techniques were used to study the relation between TPH2 gene rs7305115 SNP,interrelated environmental factors and the rate of attempted suicide. Controls were paired with cases according to the same gender, similar age (no more than 3 years) and from the same district. RESULTS: There were remarkably significant differences in gene types and gene frequency between case and control groups (P < 0.001). Data from multivariate conditional logistic regression model analysis showed that hopelessness, negative life-events and family history of suicide were relationship of attempted suicide in patients with major depression with OR values as 0.33 (95% CI: 0.22-0.99), 7.68 (95% CI: 5.79-13.74), 6.64 (95% CI: 2.48-11.04), 2.98 (95% CI: 1.17-5.04) respectively. There was no first level interaction between any of the two risk factors. CONCLUSION: Results from the study supported the idea that hopelessness, negative life-events and family history of suicide were risk factors of attempted suicide in major deprbssion while TPH2 gene rs7305115 A/A might be the protective factor.

Alterations of trace elements (Zn, Se, Cu, Fe) and related metalloenzymes in rabbit blood after severe trauma.

To investigate the status of the trace elements (TEs) and related metalloenzymes activities in the injury and repair process after severe trauma, we established a rabbit model of severe trauma whose Injury Severity Score (ISS) was 22. Concentrations of blood selenium (Se) and serum copper (Cu), zinc (Zn), iron (Fe), and ferritin were measured on D0 (before injury), and day (D) 1, D2, D3, D6, D9, D14, D21, D28 after trauma, respectively. The activities of glutathione peroxidase (GPx), Cu/Zn superoxide dismutase (Cu/Zn-SOD), myeloperoxidase (MPO), the contents of lipid peroxidation product malondialdehyde (MDA) and serum biochemical profile were detected synchronously. In addition, the morphologic changes of major organs were observed at different time intervals. Results showed that blood Se and serum Zn, Fe contents decreased significantly within 2 weeks after injury. Serum Cu concentration was significantly reduced on D1 but normalized quickly. Serum ferritin level increased during the first week while following an obvious decrease thereafter. The blood GPx activity dropped markedly from D1 to D6, the serum Cu/Zn-SOD activity decreased on D1 and then increased significantly within 2 weeks, and the blood MPO-positive stained cells increased within a week after trauma and followed by a decrease from D14 to D21. The serum MDA increased significantly on D6. Seven of 34 rabbits died in 4-6 days after injury. Biochemistry values and pathological features revealed these rabbits died of multiple organ dysfunction syndrome (MODS). Our experiment suggested that the circulating TEs status is dramatically modified in response to trauma, which might be a factor in MODS.

Reversal MDR in breast carcinoma cells by transfection of ribozyme designed according the secondary structure of mdr1 mRNA.

Multidrug resistance (MDR) is a major obstacle in cancer chemotherapy. The present study aims to investigate whether the ribozyme could reverse MDR in breast carcinoma cells. In this study, two GUC sites (GUC106 and GUC135) on the surface of mdr1 mRNA were selected according to the secondary structure of the 5'-region of mdrl mRNA. The ribozyme gene RZ106 and RZ135 complementary to two sides bases of the target GUC were synthesized and cloned into the plasmid pEGFP -C1 which has EGFP (Enhanced Green Fluorescence Protein) as report gene and Kan/Neo as selection gene. After transfection with the recombinant plasmid and selected by G418, the stable cell clones were produced and used for detection. The alteration of mdr1 mRNA and P-gp in the treated cells was detected by RT-PCR, flow cytometry and Rh123 retention. The reversal efficiency of the drug resistance for adriamycin was determined by MTT assay. The results showed that after transfection with RZ106 and RZ135, the amount of the mdr1 mRNA and P-gp decreased significantly and the efflux function of P-gp was inhibited accordingly. Nine-fold and 16-fold reduction of resistance for adriamycin was observed in the two groups of treated cells. These results suggested that both ribozymes can reverse the MDR phenotype by inhibiting the expression of mdr1 mRNA and P-gp, and the RZ135 showed the better cleavage efficiency. The ribozyme strategy designed according the secondary structure of the target RNA could be a useful therapy for reversal of MDR.