Introduction With increasing automation in clinical laboratories, the requirements for quality control (QC) material have greatly increased in order to monitor performance. The constant use of commercial control material is not economically feasible for many countries because of nonavailability or the high-cost of those materials. Therefore, preparation and use of in-house QC serum will be a very cost-effective measure with respect to laboratory needs. Materials and Methods In-house internal quality control from leftover serum samples of master health checkup subjects, which have been screened negative for HIV, HCV and HBsAg antibodies was pooled in a glass jar with ethanediol as preservative and kept in deep freezer at - 20 degrees C. From the pooled serum, 100 microliter thirty aliquots were prepared. Every day along with commercial internal QC (IQC), one aliquot of pooled serum was analyzed for 30 days for the following parameters: plasma glucose, blood urea, serum creatinine, total cholesterol, triglycerides (TGL), high-density lipoprotein, calcium, total protein, albumin, total bilirubin, AST, ALT, ALP, amylase. After getting 30 values for each parameter, mean, standard deviation (SD) and CV% were calculated for both IQC commercial sample and pooled serum sample. Results The mean, SD, and CV% of glucose, cholesterol, TGL, calcium, alanine aminotransaminase (ALT), aspartate aminotransferase (AST), amylase, and alkaline phosphatase (ALP) were statistically significant between pooled serum and commercial QC. Conclusion In-house QC prepared from pooled serum is better than commercial internal QC. The biochemical parameters were stable in pooled serum due to less matrix effect; also, variation was less in pooled serum IQC.

The interaction of ferritin iron responsive element (IRE) mRNA with eIF4F was examined by fluorescence and circular dichroism spectroscopy. Fluorescence quenching data indicated that eIF4F contains one high affinity binding site for ferritin IRE RNA. The Scatchard analysis revealed strong binding affinity (K-a = 11.1 x 10(7) M-1) and binding capacity (n = 1.0) between IRE RNA and eIF4F. The binding affinity of IRE RNA for eIF4F decreased (similar to 4-fold) as temperature increased (from 5 degrees C to 30 degrees C). The van't Hoff analysis revealed that IRE RNA binding to eIF4F is enthalpy-driven (Delta H = -47.1 +/- 3.4 kJ/mol) and entropy-opposed (Delta S = -30.1 +/- 1.5 j/mol/K). The addition of iron increased the enthalpic, while decreasing the entropic contribution towards the eIF4F.IRE RNA complex, resulting in favorable free energy (Delta G = -49.8 +/- 2.8 kJ/mol). Thermodynamic values and ionic strength data suggest that the presence of iron increases hydrogen bonding and decreases hydrophobic interactions, leading to formation of a more stable complex. The interaction of IRE RNA with elF4F at higher concentrations produced significant changes in the secondary structure of the protein, as revealed from the far-UV CD results, clearly illustrating the structural alterations resulted from formation of the eIF4F.IRE RNA complex. A Lineweaver-Burk plot showed an uncompetitive binding behavior between IRE RNA and m(7)G cap for the eIF4F, indicating that there are different binding sites on the eIF4F for the IRE RNA and the cap analog; molecular docking analysis further supports this notion. Our findings suggest that the elF4F.IRE RNA complex formation is accompanied by an elevated hydrogen bonding and weakened hydrophobic interactions, leading to an overall conformational change, favored in terms of its free energy. The conformational change in the eIF4F structure, caused by the IRE RNA binding, provides a more stable platform for effective IRE translation in iron homeostasis. (C) 2020 Elsevier B.V. All rights reserved.