The Whereabouts of 2D Gels in Quantitative Proteomics

Two-dimensional gel electrophoresis has been instrumental in the development of proteomics. Although it is no longer the exclusive scheme used for proteomics, its unique features make it a still highly valuable tool, especially when multiple quantitative comparisons of samples must be made, and even for large samples series. However, quantitative proteomics using 2D gels is critically dependent on the performances of the protein detection methods used after the electrophoretic separations. This chapter therefore examines critically the various detection methods (radioactivity, dyes, fluorescence, and silver) as well as the data analysis issues that must be taken into account when quantitative comparative analysis of 2D gels is performed

Is the formula of Traub still up to date in antemortem blood glucose level estimation?

According to the hypothesis of Traub, also known as the 'formula of Traub', postmortem values of glucose and lactate found in the cerebrospinal fluid or vitreous humor are considered indicators of antemortem blood glucose levels. However, because the lactate concentration increases in the vitreous and cerebrospinal fluid after death, some authors postulated that using the sum value to estimate antemortem blood glucose levels could lead to an overestimation of the cases of glucose metabolic disorders with fatal outcomes, such as diabetic ketoacidosis. The aim of our study, performed on 470 consecutive forensic cases, was to ascertain the advantages of the sum value to estimate antemortem blood glucose concentrations and, consequently, to rule out fatal diabetic ketoacidosis as the cause of death. Other biochemical parameters, such as blood 3-beta-hydroxybutyrate, acetoacetate, acetone, glycated haemoglobin and urine glucose levels, were also determined. In addition, postmortem native CT scan, autopsy, histology, neuropathology and toxicology were performed to confirm diabetic ketoacidosis as the cause of death. According to our results, the sum value does not add any further information for the estimation of antemortem blood glucose concentration. The vitreous glucose concentration appears to be the most reliable marker to estimate antemortem hyperglycaemia and, along with the determination of other biochemical markers (such as blood acetone and 3-beta-hydroxybutyrate, urine glucose and glycated haemoglobin), to confirm diabetic ketoacidosis as the cause of death

Induction of NANOG expression by targeting promoter sequence with small activating RNA antagonizes retinoic acid-induced differentiation

RNAa (RNA activation) is a mechanism by which small dsRNA (double-stranded RNA), termed saRNA (small activating RNA), target promoter sequences to induce gene expression. This technique represents a novel approach to gene overexpression without the use of exogenous DNA. In the present study, we investigated whether RNAa can modulate expression of the development-related gene NANOG and manipulate cell fate. Using a lentivirus-based reporter system as a screening tool, we identified synthetic saRNAs that stimulate NANOG expression in human NCCIT embryonic carcinoma cells. Mismatch mutations to saRNA duplexes define sequence requirement for gene activation. Functional analysis of NANOG induction reveals saRNA treatment predictably modulates the expression of several known downstream target genes, including FOXH1 (forkhead box H1), REST (RE1-silencing transcription factor), OCT4 (octamer-binding protein 4) and REX1 (reduced expression protein 1). Treatment with RA (retinoic acid) triggers NCCIT cell differentiation, reducing NANOG and OCT4 expression and up-regulating several neural markers [i.e. ASCL1 (achaete-scute complex homologue 1), NEUROD1 (neuronal differentiation 1) and PAX6 (paired box 6)]. However, co-treatment with saRNA antagonizes NANOG down-regulation and RA-induced differentiation. Ectopic overexpression of NANOG via lentiviral transduction further recapitulates saRNA results, providing proof-of-concept that RNAa may be utilized to activate development-related genes and manipulate cell fate