[Difference analysis of genome-wide DNA methylation status of CpG islands between the monozygotic twins with disconcordant phenotypes of chronic hepatitis B virus infection].

OBJECTIVE: To analyse the difference of genome-wide DNA methylation status of CpG island between the monozygotic twins with disconcordant phenotype of HBV infection and to discover possible differentially methylated genes. METHODS: Modified AIMS (amplification of inter-methylated sites) method was adopted. According to the frequent sites of CpG islands (-CGCG- and -CCGG-), three groups of isochizomers with distinct methylation sensitivity (Sma I-Xma I, Hpa II-Msp I and BssH II-Pau I/BseP I) were used to modify the AIMS method. The modified AIMS method combined with Personal Molecular Imager FX system analysis and radioautographic analysis was used to make the global detection of the methylome of CpG islands. Multiple anonymous bands were compared between the twins with the Quantity One bio-soft. The different bands were cloned into T vectors and positive clones were sequenced. BLAST analysis of positive clone sequences was conducted to give the clues for the differential methylated genes between monozygotic twins with discordant phenotype of HBV infection. RESULTS: Nearly the same bands were found between one pair of twins with concordant phenotype of HBV infection. Different methylated bands were found not only between monozygotic twins with concordant phenotype but also between those with disconcordant phenotype. More differential methylated bands were found in the latter groups. By BLAST analysis with sequences of differential methylated bands, four possible genes were got. These genes might relate to the monozygotic twins with disconcordant phenotype of chronic HBV infection. CONCLUSION: Differential methylation of genes occurs in monozygotic twins with discordant phenotype of HBV infection. Whether these changes are involved in the pathogenesis of different phenotypes needs further elucidation.

[The influence of abnormally higher WBC on hemoglobin determination and its redress].

OBJECTIVE: To discuss the influence of abnormally higher white blood cell (WBC) on hemoglobin (Hb) determination and work for its redress. METHODS: High WBC concentration suspensions of 48 concentration gradients were prepared to be determined in the pre-dilution pattern of automated hematology analyzer while the changes of Hb concentration before and after removal of WBC being observed. At the same time, a regression equation was set up to correct errors and redress the Hb concentration. Then, the data from 14 whole blood samples with abnormally higher WBC were used in this regression equation to verify its utility. RESULTS: The Hb concentration of samples with abnormally higher WBC was higher than that of samples where WBC was removed (P<0.001). While WBC count > or = 40.0 x 10(9)/L, there was logarithmic linear correlation between Hb concentration difference and WBC count (r=0.9526). Using the regression equation Y (Hb difference) = -25.09 + 21.89 x lg[WBC (x 10(9)/L)], we found that there was no significant difference (P>0.05) between the "practically detected Hb difference" and the "theoretically adjusted Hb difference" in the whole blood samples with abnormally higher WBC. CONCLUSION: Abnormally higher WBC may lead to increase of error in the detection of Hb concentration; the ultimate result in close proximity to true Hb concentration of whole blood samples with abnormally higher WBC can be acquired through the linear regression equation.