Expression phenotype changes of EBV-transformed lymphoblastoid cell lines during long-term subculture and its clinical significance.

OBJECTIVES: The EBV-transformed lymphoblastoid cell line (LCL) is a useful resource for population-based human genetic and pharmacogenetic studies. The principal objective here was to assess expression phenotype changes during long-term subculture of LCLs, and its clinical significance. MATERIALS AND METHODS: We searched for genes that were differentially expressed in 17 LCLs at late (p161) passage compared to early passage (p4) using microarray assay, then validated them by real-time RT-PCR analysis. In addition, we estimated correlations between expression phenotypes of 20 LCL strains at early passage and 23 quantitative clinical traits from blood donors of particular LCL strains. RESULTS: Transcript sequences of 16 genes including nuclear factor-kappaB (NF-kappaB) pathway-related genes (such as PTPN13, HERC5 and miR-146a) and carcinogenesis-related genes (such as XAF1, TCL1A, PTPN13, CD38 and miR-146a) were differentially expressed (>2-fold change) in at least 15 of the 17 LCL strains. In particular, TC2N, FCRL5, CD180, CD38 and miR-146a were downregulated in all 17 of the evaluated LCL strains. In addition, we identified clinical trait-associated expression phenotypes in LCLs. CONCLUSION: Our results showed that LCLs acquired expression phenotype changes involving expression of NF-kappaB pathway- and carcinogenesis-related genes during long-term subculture. These differentially expressed genes can be considered to be a gene signature of LCL immortalization or EBV-induced carcinogenesis. Clinical trait-associated expression phenotypes should prove useful in the discovery of new candidate genes for particular traits.

Identification of tumor necrosis factor signaling-related proteins during Epstein-Barr virus-induced B cell transformation.

Epstein-Barr virus (EBV) infection in vitro transforms primary B cells into continuously proliferating lymphoblastoid cell lines (LCLs) that have been widely used as a genomic resource for variety of immunological and genetic studies. However, the biochemical and biological characteristics that distinguish LCLs from the B cells have not been thoroughly investigated. Our proteomic approach showed that EBV infection induced changes in the profiles of tumor necrosis factor (TNF) signaling-related proteins in LCLs including heat shock protein family members TNF receptor-associated protein 1 (TRAP-1), heat shock 70-kDa protein 9 (HSPA9)) and superoxide dismutase 2 (SOD2). In addition, our literature co-occurrence study placed TNF at the center of a gene cluster network of differentially expressed proteins in LCLs. This study suggested that deregulation of TNF signaling pathway could contribute to the cellular transformation and immortalization of the EBV-infected B cells.

Analysis of mercury in sportfish tissue by thermal decomposition, amalgamation/atomic absorption spectrophotometry.

Sportfish samples (n = 133) that originated from Indiana waters were analyzed for total mercury using inductively coupled plasma/mass spectrometry (ICP/MS) and thermal decomposition, amalgamation/atomic absorption spectrophotometry (TDA/ AAS). Total mercury concentrations obtained by the two methods were not significantly different (P > 0.05). The correlation coefficient for total mercury obtained for the two methods was 0.94. The limit of detection using TDA/AAS was 0.1 ppm. TDA/AAS is a preferred technique for the analysis of total mercury in fish tissue because it is rapid (6 min per sample) and easy to use and requires little sample preparation.

Mercury and omega-3 fatty acids in retail fish sandwiches.

Mercury and fatty acids were measured in fish sandwiches from six retail restaurant chains. Average mercury concentrations ranged from 5 to 132 ppb and were well below the Food and Drug Administration action level (1,000 ppb). The average concentrations of eicosapentaenoic acid plus docosahexaenoic acid ranged from 91 to 620 mg per sandwich. Consuming one or two fish sandwiches per week could result in the consumption of 2 to 40% of the reference dose for mercury for a 60-kg individual and would provide 18 to 126% of the adequate intake for eicosapentaenoic acid plus docosahexaenoic acid as recommended for a pregnant or lactating woman.

Prediction of PCB content in sportfish using semipermeable membrane devices (SPMDs).

Triolein-filled semipermeable membrane devices (SPMDs) were immersed at three locations along the St. Joseph River in northern Indiana for 30 days to see if the PCB content of fish from the same location could be predicted with this model device. Triolein from the SPMD's was analyzed for PCB using enzyme-linked immunosorbent assay (ELISA) and compared to residues detected in fish collected from the same locations. There was a significant difference (p < 0.05) in total PCB concentrations between SPMD samples. However, due to variability in PCB residues between species and low PCB residues in SPMDs, a direct correlation between PCBs in sportfish and SPMDs could not be determined.