ObjectiveTo explore the action of dominant-negative effect on mutant insulin gene-induced diabetes.Methods293T cells were transfected with a recombinant plasmid containing mutant preproinsulinogen complementary DNA (cDNA) and a recombinant plasmid containing human wild-type preproinsulinogen cDNA. There were 5 mutant groups which mutant preproinsulins respectively bear substitutions V(A3)L, C(A7)Y, R(SP6)H, G(B8)S or G(C28)R. Wild-type mouse preproinsulin and wild-type human preproinsulin were co-transfected as normal control group. After 48 hours, medium and cells were collected. Human proinsulin were detected by human-specific proinsulin radioimmunoassay.ResultsCompared with the control group [(135.84±1.89) pmol/L], human proinsulin levels in medium of C(A7)Y group [(29.28±6.85) pmol/L] and G(B8)S group[(33.62±10.52) pmol/L] decreased significantly (P<0.01). There was no significant difference in human proinsulin level between the other groups and the control group (P>0.05).ConclusionMutants C(A7)Y and G(B8)S induce the dominant-negative effect on co-existing wild-type proinsulin.
【Abstract】Objective To explore the differential diagnostic value of major fibrinolytic parameters in pleural fluid. Methods Tissue-type plasminogen activator( t-PA) and plasminogen activator inhibitor-1( PAI-1) in pleural fluid at the first thoracentesis were measured with ELISA and D-dimer was measured with immunoturbidimetry. Results Eighty-four patients with pleural effusion were enrolled, among which 40 with malignant effusion, 33 with infectious effusion and 11 with transudative effusion. t-PA level was higher in malignant and transudative pleural fluid than that in infectious pleural fluid[ ( 52. 49 ±31. 46) ng /mL and ( 58. 12 ±23. 14) ng /mL vs ( 37. 39 ±22. 44) ng /mL, P lt; 0. 05] , but was not statistically different between malignant pleural fluid and transudative ( P gt; 0. 05) . PAI-1 level was higher in malignant and infectious pleural fluid than that in transudative [ ( 164. 86 ±150. 22) ng/mL and ( 232. 42 ±175. 77) ng/mL vs ( 46. 38 ±16. 13) ng/mL, P lt; 0. 01] , but was not statistically different between malignant and infectious pleural fluid( P gt;0. 05) . D-dimer levels in the three types of pleural fluid were significantly different, which was ( 23. 66 ±25. 18) mg/L, ( 6. 36 ±10. 87) mg/L and ( 66. 90 ±42. 17) mg/L in malignant, transudative and infectious pleural fluid, respectively. As single-item detection for malignant pleural fluid, the cutoff of t-PA was gt; 38. 7 ng/mL( area under ROC curve was 64. 0 ) , with sensitivity of 60. 0% , specificity of 63. 6%, positive predictive value of 66. 7%, negative predictive value of 56. 8% and accuracy of 61. 6% .The cutoff of D-dimer was lt; 27. 0 mg/L( area under ROC curve was 85. 5) , with sensitivity of 84. 8% ,specificity of 72. 5% , positive predictive value of 85. 3% , negative predictive value of 71. 8% and accuracy of78.1%. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of combined examination( t-PA + D-dimer) were 92. 5% , 60. 6% , 74. 0% , 87. 0% , 78. 1% , respectively.Conclusions The t-PA, PAI-1 and D-dimer levels are significantly different in the three types of pleural fluid. The detection of fibrinolytic parameters in pleural fluid, especially the value of D-dimer,may be helpful in the differential diagnosis of pleural effusion.
The purpose of this study is to reveal the protective effect of rib cage on scoliotic spine by comparing the different effect of rib cage on the stability of normal spine and Lenke1 scoliotic spine. Firstly, according to X-ray computed tomography (CT) image data, four spinal finite element models (SFEMs), including normal spine without rib cage (N1), normal spine with normal rib cage (N2), scoliotic spine without rib cage (S1) and scoliotic spine with deformed rib cage (S2), from the first thoracic vertebrae to the sacral vertebrae (T1～S) were established. Secondly, the natural vibration characteristics of the four SFEMs were obtained by modal analysis. Finally, the maximum vibration amplitudes of the four SFEMs under external excitation were obtained by steady-state analysis. As shown in results, compared with N1, the maximum deformation of N2 segment T4～T6 in the X-axis (coronal axis), Y-axis (sagittal axis) and Z-axis (vertical axis) directions decreases by 38.44%, 53.80% and 33.72%, respectively. Compared with S1, the maximum deformation of S2 segment T4～T6 in the X-axis direction, Y-axis direction and Z-axis directions decreases by 44.26%, increases by 32.80% and decreases by 49.23%, respectively. As it can be seen, for normal spine, the rib cage can improve the stability of the whole spine in three directions; for the Lenke1 scoliotic spine, the rib cage can reduce the vibration of the scoliotic spine in the X-axis and Z-axis directions and improves the stability of the whole spine in the two directions, while in the Y-axis direction, for the serious severe anteversion of scoliotic spine, the deformed rib cage exacerbates the vibration of the scoliotic spine in this direction and destroys the stability of the scoliotic spine in the Y-axis direction. This study reveals the biomechanical characteristics of rib caged influence on the stability of the scoliotic spine and it has guiding significance for the study of daily protection methods and protective tools for scoliotic patients.