Decreases in blood perfusion of the anterior cingulate gyri in Anorexia Nervosa Restricters assessed by SPECT image analysis

BACKGROUND: It is possible that psychopathological differences exist between the restricting and bulimic forms of anorexia nervosa. We investigated localized differences of brain blood flow of anorexia nervosa patients using SPECT image analysis with statistic parametric mapping (SPM) in an attempt to link brain blood flow patterns to neurophysiologic characteristics. METHODS: The subjects enrolled in this study included the following three groups: pure restrictor anorexics (AN-R), anorexic bulimics (AN-BP), and healthy volunteers (HV). All images were transformed into the standard anatomical space of the stereotactic brain atlas, then smoothed. After statistical analysis of each brain image, the relationships among images were evaluated. RESULTS: SPM analysis of the SPECT images revealed that the blood flow of frontal area mainly containing bilateral anterior cingulate gyri (ACC) was significantly decreased in the AN-R group compared to the AN-BP and HV groups. CONCLUSIONS: These findings suggest that some localized functions ofthe ACCare possibly relevant to the psychopathological aspects of AN-R

Biochemical behavior of N-oxidized cytosine and adenine bases in DNA polymerase-mediated primer extension reactions

To clarify the biochemical behavior of 2′-deoxyribonucleoside 5′-triphosphates and oligodeoxyribonucleotides (ODNs) containing cytosine N-oxide (Co) and adenine N-oxide (Ao), we examined their base recognition ability in DNA duplex formation using melting temperature (Tm) experiments and their substrate specificity in DNA polymerase-mediated replication. As the result, it was found that the Tm values of modified DNA–DNA duplexes incorporating 2′-deoxyribonucleoside N-oxide derivatives significantly decreased compared with those of the unmodified duplexes. However, single insertion reactions by DNA polymerases of Klenow fragment (KF) (exo−) and Vent (exo−) suggested that Co and Ao selectively recognized G and T, respectively. Meanwhile, the kinetic study showed that the incorporation efficiencies of the modified bases were lower than those of natural bases. Ab initio calculations suggest that these modified bases can form the stable base pairs with the original complementary bases. These results indicate that the modified bases usually recognize the original bases as partners for base pairing, except for misrecognition of dATP by the action of KF (exo−) toward Ao on the template, and the primers could be extended on the template DNA. When they misrecognized wrong bases, the chain could not be elongated so that the modified base served as the chain terminator