We have previously argued that unrepaired
G:T mismatches from spontaneous deamination of 5-methylcytosine at CpG sites could be converted to apparent in vivo mutations in the bacterial recovery systems because of rapid, random, mismatch repair in Escherichia coli. In this study, we have measured mutation frequencies in spleen of male mice induced by N-ethyl-N-nitrosourea (ENU) using the Phi X174 transgene, which is not subject to mismatch repair in E.coli, using single-burst analysis, a unique method to identify in vivo mutation. In order to compare our results to those using the lacI and cII transgenes, we converted all mutant frequencies to base pair Autophagy inhibitor in vitro substitution (bps) mutation frequencies per nucleotide based on mutant spectra from this study and published literature. We found this frequency in control spleen to be similar for lacI (3.8 +/- 0.7 x 10(-8)) and Phi X174 (3.1 +/- 1.2 x 10(-8)) at 6 weeks of age. We found a strong age dependence for spontaneous lacI mutation that extrapolated to a value at conception (1.8 +/- 0.9 x 10(-8)) that was not significantly different from the human germ line bps mutation frequency per nucleotide of 1.7 +/- 0.2 x 10(-8). These two transgenes provided similar
mutational responses to 40 mg/kg ENU, 7- to 9-fold. In contrast, the cII target gene in the same tissue produces both spontaneous and induced mutation frequencies similar to 10 times higher, for unknown reasons. We www.selleckchem.com/products/sbi-0206965.html conclude that the spontaneous mutant frequencies measured by the lacI and Phi X174 transgenes in this moderately dividing tissue accurately measure in vivo mutation frequencies at early ages. For these two transgenes, Wnt activation seemingly high mutant frequencies may reflect the expected accumulation of somatic mutation with age.”
“Extracellular purine and pyrimidine
compounds induce a multiplicity of cellular signal pathways that can induce multiple trophic functions. They interact with other low molecular weight messengers, growth factors, and extracellular matrix components. An increasing number of studies now provide evidence for a role of purinergic signaling in neural development, including progenitor cell proliferation, cell migration, neuronal and glial maturation and differentiation, and cell death and survival. This brief overview highlights recent developments supporting a contribution of purinergic signaling to embryonic and adult neurogenesis. (C) 2011 Elsevier Ltd. All rights reserved.”
“We report a case of bilateral ulna stress fractures following bilateral femoral fractures associated with long-term bisphosphonate use. The patient is an 84-year-old woman receiving 15 years of bisphosphonate therapy.