Influence of Genetic Background and Tissue Types on Global DNA Methylation Patterns

Recent studies have shown a genetic influence on gene expression variation, chromatin, and DNA methylation. However, the effects of genetic background and tissue types on DNA methylation at the genome-wide level have not been characterized extensively. To study the effect of genetic background and tissue types on global DNA methylation, we performed DNA methylation analysis using the Affymetrix 500K SNP array on tumor, adjacent normal tissue, and blood DNA from 30 patients with esophageal squamous cell carcinoma (ESCC). The use of multiple tissues from 30 individuals allowed us to evaluate variation of DNA methylation states across tissues and individuals. Our results demonstrate that blood and esophageal tissues shared similar DNA methylation patterns within the same individual, suggesting an influence of genetic background on DNA methylation. Furthermore, we showed that tissue types are important contributors of DNA methylation states

In-beam investigation and the structure of states in "1"1"3Sn

The results of in-beam investigations of "1"1"3Sn using the (p,n), (p,3n), (#alpha#,n) and (#alpha#,2n) reactions are summarized. Excited states have been identified until E_x=4715 MeV and J"#pi#=(27/2"-). For a large number of levels mean lifetimes #tau# have been determined with the DSA method. For the J"#pi#=25/2"+ state at E_x=4059 MeV, #tau#=1.0(4) ns has been measured with the #gamma#-RF method. The experimental results are compared with the predictions of shell-model calculations. Most of the positive-parity states may be considered as one- or three-quasiparticle neutron excitations of the 2d_5_/_2, 1g_7_/_2, 3s_1_/_2 and 2d_3_/_2 shells, the negative-parity states as the coupling of one 1h_1_1_/_2 neutron to the two- or four-quasiparticle neutron excitations in the even-mass "1"1"2Sn core. For the 25/2"+ isomer the three-quasiparticle neutron configuration #nu#(h"2_1_1_/_2g"-"1_7_/_2) has been proposed on the basis of a shell-model analysis using the mass formula formalism. The experimentally observed yrast states in _5_0"1"1"3Sn_6_3 are compared with the corresponding states in the valence-mirror nucleus _6_3"1"4"5Eu_8_2 giving remarkable similarities although the parameters for the shell-model calculations differ considerably. The analysis of nearest-neighbour spacing distributions of 5/2"+ states in "1"1"3Sn does not allow definite conclusions about regularity or chaos. (orig.)59 refs.Available from TIB Hannover: RR 1847(95) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman