Expression of β-nerve growth factor mRNA in rat glioma cells and astrocytes from rat brain

AbstractA 50-base synthetic oligodeoxynucleotide complementary to a portion of mouse nerve growth factor (NGF) mRNA was used as a probe for analysis of the expression of NGF gene. Northern blot analysis showed the presence of a major 1.3 kb transcript, which was identical in size to mouse NGF mRNA, in both C6Bu1 cells and rat astrocytes cultured from newborn rat brain. Further, the rearrangement of DNA sequence in and around the NGF gene locus of C6Bu1 cells was not detected by Southern blot analysis. These results indicate the expression of NGF mRNA in both C6Bu1 cells and astrocytes from rat brain, suggesting that astrocytes may produce NGF protein in the rat brain, especially in developing rat brain

Comparative Evaluation of Plasma Metabolomic Data from Multiple Laboratories

In mass spectrometry-based metabolomics, the differences in the analytical results from different laboratories/machines are an issue to be considered because various types of machines are used in each laboratory. Moreover, the analytical methods are unique to each laboratory. It is important to understand the reality of inter-laboratory differences in metabolomics. Therefore, we have evaluated whether the differences in analytical methods, with the exception sample pretreatment and including metabolite extraction, are involved in the inter-laboratory differences or not. In this study, nine facilities are evaluated for inter-laboratory comparisons of metabolomic analysis. Identical dried samples prepared from human and mouse plasma are distributed to each laboratory, and the metabolites are measured without the pretreatment that is unique to each laboratory. In these measurements, hydrophilic and hydrophobic metabolites are analyzed using 11 and 7 analytical methods, respectively. The metabolomic data acquired at each laboratory are integrated, and the differences in the metabolomic data from the laboratories are evaluated. No substantial difference in the relative quantitative data (human/mouse) for a little less than 50% of the detected metabolites is observed, and the hydrophilic metabolites have fewer differences between the laboratories compared with hydrophobic metabolites. From evaluating selected quantitatively guaranteed metabolites, the proportion of metabolites without the inter-laboratory differences is observed to be slightly high. It is difficult to resolve the inter-laboratory differences in metabolomics because all laboratories cannot prepare the same analytical environments. However, the results from this study indicate that the inter-laboratory differences in metabolomic data are due to measurement and data analysis rather than sample preparation, which will facilitate the understanding of the problems in metabolomics studies involving multiple laboratories