2,976 research outputs found
Predictive value of CHA(2)DS(2)-VASc and CHA(2)DS(2)-VASc-HS scores for failed reperfusion after thrombolytic therapy in patients with ST-segment elevation myocardial infarction
No full textBackground: Thrombolytic therapy is recommended for patients with acute ST-segment elevation myocardial infarction (STEMI) who cannot undergo primary percutaneous coronary intervention within the first 120 min. The aim of this study was to demonstrate the value of CHA(2)DS(2)-VASc and CHA(2)DS(2)-VASc-HS scores in predicting failed reperfusion in STEMI patients treated with thrombolytic therapy. Methods: A total of 537 consecutive patients were enrolled in the study; 139 had failed thrombolysis while the remaining 398 fulfilled the criteria for successful thrombolysis. Thrombolysis failure was defined with the lack of symptom relief = 2 with a sensitivity of 80.90% and a specificity of 41.01% (area under curve IAUC] 0.660; 95% confidence interval [CI] 0.618-0.700; p < 0.001) and the cut-off value of CHA(2)DS(2)-VASc-HS score was 3 with a sensitivity of 76.13% and a specificity of 67.63% (AUC 0.764; 95% CI 0.725-0.799; p < 0.001). The CHA,DS r VASc-HS score was found to be statistically and significantly better than CHA(2)DS(2)-VASc score to predict failed reperfusion (p < 0.001). Conclusions: The findings suggest that the CHA(2)DS(2)-VASc and especially CHA(2)DS(2)-VASc-HS scores could be considered as predictors of risk of failed repolusion in STEMI patients
Statistical optimization for immobilized metal affinity purification of secreted human erythropoietin from Drosophila S2 cells
No full textWe used a novel approach to affinity purify human erythropoietin (hEPO) following its secretion from Drosophila melanogaster S2 cells. Immobilized metal affinity purification of hEPO was optimized using a two-step serial statistical optimization strategy. After determining the elution conditions (based on preliminary batch-type purification experiments), the first optimization step considered three purification factors; resin, equilibrium, and washing. The results of this analysis showed that the resin amount was the major factor influencing yield and purity in both model equations and the washing factor lowered the confidence limits of the acquired model equations. The washing conditions were then set based on the results of the first step optimization and the second step then optimized three factors; resin, equilibrium, and elution. The yield and purity of hEPO were then compared following purification using three different approaches; batch-type purification based upon the conditions determined by serial statistical optimization, batch-type purification performed in preliminary experiments, and FPLC column chromatography-type purification. We found that the serial statistical optimization approach provided the best combination of yield and purity. These findings indicate that serial statistical optimization strategies can be successfully employed for immobilized metal affinity protein purification using either batch-type or column approaches. (C) 2002 Elsevier Science (USA). All rights reserved.X1118sciescopu
Facile and statistical optimization of transfection conditions for secretion of foreign proteins from insect Drosophila S2 cells using green fluorescent protein reporter
No full textInsect Drosophila melanogaster S2 cells were developed as a plasmid-based and therefore nonlytic expression system for functional foreign proteins. Transfection is an important step to introduce foreign target DNA into cells and should be properly optimized to obtain maximum production yield. Single factor search (SFS) methodology is still generally used to determine optimal condition in a biological system. Although this method is relatively simple to perform it has many disadvantages such as not considering interactions between several factors and not covering the entire region of the solution pool. Therefore, we approached this optimization problem statistically with response surface (RSM) and evolutionary operation (EVOP) methodologies and compared the transfection efficiencies with the traditional SFS method. We employed secreted green fluorescent protein (GFP) as a reporter for determination of optimal transfection condition and secreted human erythropoietin (hEPO) as a confirming foreign model protein. Consequently, we arrived at the best optimal transient transfection condition (1 mug of plasmid DNA, 5 mug of lipofectin, 2 x 10(6) cells of initial cell number, and 18 h of transfection duration time) through a systematic access in a series of SFS, RSM, and EVOP. The secreted hEPO yield using optimal transient transfection condition by EVOP methodology was enhanced by about 1.8-fold compared to that of traditional SFS. This optimized transient transfection condition can be used as a basis for optimal stable transfections. A linear relationship between secreted GFP fluorescence intensity and secreted hEPO concentration indicated that facile and noninvasive determination of optimal transfection. conditions for expression and secretion of foreign proteins in S2 cell cultures was made possible by simple measurement of GFP fluorescence.X111721sciescopu
Thermal and electrochemical properties of morpholinium salts with bromide anion
No full textThe present work is a study of the thermal properties and electrochemical stabilities of N-ethyl-N-methyl-morpholinium bromide ([Mor(1.2)][Br]), N-butyl-N-methylmorpholinium bromide ([Mor(1.4)][Br]), N-butyl-N-methylmorpholinium bromide ([Mor(1.8])[Br]), N-dodecyl-N-methylmorpholinium bromide ([Mor(1,12)] [Br]), and N,N-dihydroxyethylmorpholinium bromide ([DHEMor][Br]). The melting points, decomposition temperatures, and electrochemical stabilities of the salts were measured by DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), and CV (cyclic voltammogram), respectively. All salts were decomposed below approximately 230.00 degrees C and their melting points were above 100.00 degrees C except [DHEMor][Br], which melted at 75.17 degrees C. [DHEMor][Br] appeared to possess the most wide liquid-phase range between melting point and decomposition temperature. The electrochemical windows of salts ranged from 3.3 V for [Mor(1)(8)(.)][Br] to 3.6 V for [Mor(1.4)][Br] and thus did not show any noticeable variation with cations used for salt synthesis
Analysis of polymorphism of the GLUT2 promoter in NIDDM patients and its functional consequence to the promoter activity
No full textGlucose transporter type 2 (GLUT2), along with glucokinase, has been implicated to participate in glucose-induced insulin secretion in pancreatic beta-cells. Recently, several sequence variations in the promoter of GLUT2 have been identified in patients with non-insulin dependent diabetes mellitus (NIDDM), but the functional effects of these polymorphisms on promoter activity have not previously been studied. We compared the incidence of sequence variations in the GLUT2 promoter in 100 normal subjects and 100 NIDDM patients. Sequencing of the promoter region (-294 to +301) revealed that an A-->G variant at position -44 was found in 45 of 100 NIDDM patients, but only in 23 of 100 normal subjects. In addition, -269 A-->C and +103 A-->G mutations were identified in a single diabetic patient. Electrophoretic mobility shift assays using double-stranded oligonucleotide containing -44A as a probe showed a clearly shifted band of DNA-protein. To examine whether the sequence variation at position -44 affects the promoter activity, we carried out in vitro transfection experiments. Site-specific mutagenesis at position -44 region from A to C, T or G resulted in reductions of CAT activity by 52.3%, 63.8%, and 63.6%, respectively. The -269 A-->C and +103 A-->G mutations also decreased the promoter activity. These results suggest that polymorphisms at positions -269, -44, or +103 may affect GLUT2 gene transcription, possibly associated with reduced expression of the GLUT2 gene in NIDDM patients
Partial recovery of cell membrane-bounded human interleukin-2 fusion protein from insect cell debris by using various detergent extractions
No full textWe previously found that the human interleukin-2 (hIL-2) fused with green fluorescent protein (GFP) mainly remained in the insect cell debris after disruption due to the highly hydrophobic property of hIL-2 itself. Even though the significant GFPuv/hIL-2 fusion proteins were associated with cell membrane fractions, these were still functionally active. Therefore, to increase the total product yield, we performed partial recovery of the cell membrane-bounded hIL-2 fusion protein from the insoluble cell debris using several non-ionic, zwitterionic, and anionic detergents.X111sciescopu
Crystallization and Preliminary X-ray crystallographic Analyses of the Helicase Domain of Hepatitis C Virus NS3 Protein
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