Comparison of Hepatitis B Virus DNA, RNA, and Core Related Antigen as Predictors of Lamivudine Resistance in Patients with Chronic Hepatitis B

The clinical usefulness of hepatitis B virus (HBV)DNA, RNA, and core related antigen (HBcrAg)assays for predicting the appearance of HBV DNA breakthrough was evaluated and compared in patients with chronic hepatitis B undergoing lamivudine therapy.Methods :Thirty six patients with chronic hepatitis B who received lamivudine therapy for more than 1 year were enrolled. HBV RNA was measured simultaneously with HBV DNA (HBV RNA/DNA) using a real-time detection polymerase chain reaction assay with a preceding step of reverse-transcription. HBV DNA was measured by an HBV AMPLICOR monitor kit. HBcrAg was measured using a chemiluminescence enzyme immunoassay. Results : Sixteen patients (44%) developed HBV DNA breakthrough during the median observation period of 48.4 months (range 7.4-87.8 months). Afterwards, HBV DNA breakthrough was prospected using the three parameters taken 6 months after starting lamivudine therapy. The cut-offlevels for predictions were determined by receiver operating characteristic curves, and were 2.6 log copies/ml for HBV DNA, 3.8 log U/ml for HBV RNA/DNA, and 4.0 log U/ml for HBcrAg.Sensitivity,specificity,and accuracy for predicting HBV DNA breakthrough were 25%, 100%,and 67% respectively for HBV DNA.Similarly,they were 50%,90%,and 72% for HBV RNA/DNA, and 100%, 40%, and 67% for HBcrAg. Conclusion : Our findings confirm that HBV DNA is useful for identifying patients who are at high risk for HBV breakthrough.HBcrAg is useful for isolating those who are at low risk, and HBV RNA/DNA showed predictive characteristics similar to HBV DNA with higher sensitivity and the highest accuracyArticle信州医学雑誌, 58(4):153-162 (2010)departmental bulletin pape

Analysis of Ribosomal Protein Gene Structures: Implications for Intron Evolution

Many spliceosomal introns exist in the eukaryotic nuclear genome. Despite much research, the evolution of spliceosomal introns remains poorly understood. In this paper, we tried to gain insights into intron evolution from a novel perspective by comparing the gene structures of cytoplasmic ribosomal proteins (CRPs) and mitochondrial ribosomal proteins (MRPs), which are held to be of archaeal and bacterial origin, respectively. We analyzed 25 homologous pairs of CRP and MRP genes that together had a total of 527 intron positions. We found that all 12 of the intron positions shared by CRP and MRP genes resulted from parallel intron gains and none could be considered to be “conserved,” i.e., descendants of the same ancestor. This was supported further by the high frequency of proto-splice sites at these shared positions; proto-splice sites are proposed to be sites for intron insertion. Although we could not definitively disprove that spliceosomal introns were already present in the last universal common ancestor, our results lend more support to the idea that introns were gained late. At least, our results show that MRP genes were intronless at the time of endosymbiosis. The parallel intron gains between CRP and MRP genes accounted for 2.3% of total intron positions, which should provide a reliable estimate for future inferences of intron evolution

Improvement of Propylene Epoxidation Caused by Silver Plasmon Excitation by UV-LED Irradiation on a Sodium-Modified Silver Catalyst Supported on Strontium Carbonate

The effect that UV-LED irradiation exerted on a sodium-modified silver catalyst supported on strontium carbonate (Ag-Na/SrCO3) was examined during an epoxidation of propylene to propylene oxide. Based on our previous study, we used Ag(56)-Na(1)/SrCO3 in this study. The numbers in parentheses refer to the weight percentage of silver and sodium. Although this catalyst system did not contain typical photocatalysts such as titanium oxide or tungsten oxide, UV-LED irradiation of Ag(56)-Na(1)/SrCO3 resulted in an evident improvement in the selectivity and yield of propylene oxide. Such an advantageous effect of UV-LED irradiation could not be discussed based on the bandgap used in photocatalysts and, therefore, we proposed a mechanism based on the plasmon excitation of silver, which could be accomplished using the irradiation wavelength of UV-LED to produce electrons. Since the lifespan of these electrons is expected to be short, it is difficult to place them into direct contact with the gas phase of oxygen. Once the generated electrons move to SrCO3, however, the lifespan is improved, which could allow suitable contact with oxygen in the gas phase to form active oxygen. If the oxygen is active for epoxidation as hydrogen peroxide, this could explain the improvement in activity from UV-LED irradiation

COOH-terminal isoleucine of lysosome-associated membrane protein-1 is optimal for its efficient targeting to dense secondary lysosomes.

Lysosome-associated membrane protein-1 (LAMP-1) consists of a highly glycosylated luminal domain, a single-transmembrane domain and a short cytoplasmic tail that possesses a lysosome-targeting signal (GYQTI(382)) at the COOH terminus. It is hypothesized that the COOH-terminal isoleucine, I(382), could be substituted with any other bulky hydrophobic amino acid residue for LAMP-1 to exclusively localize in lysosomes. In order to test this hypothesis, we compared subcellular distribution of four substitution mutants with phenylalanine, leucine, methionine and valine at the COOH-terminus (termed I382F, I382L, I382M and I382V, respectively) with that of wild-type (WT)-LAMP-1. Double-labelled immunofluorescence analyses showed that these substitution mutants were localized as significantly to late endocytic organelles as WT-LAMP-1. However, the quantitative subcellular fractionation study revealed different distribution of WT-LAMP-1 and these four COOH-terminal mutants in late endosomes and dense secondary lysosomes. WT-LAMP-1 was accumulated three to six times more in the dense lysosomal fraction than the four mutants. The level of WT-LAMP-1 in late endosomal fraction was comparable to those of I382F, I382M and I382V. Conversely, I382L in the late endosomal fraction was approximately three times more abundant than WT-LAMP-1. These findings define the presence of isoleucine residue at the COOH-terminus of LAMP-1 as critical in governing its efficient delivery to secondary lysosomes and its ratio of lysosomes to late endosomes.Lysosome-associated membrane protein-1 (LAMP-1) consists of a highly glycosylated luminal domain, a single-transmembrane domain and a short cytoplasmic tail that possesses a lysosome-targeting signal (GYQTI(382)) at the COOH terminus. It is hypothesized that the COOH-terminal isoleucine, I(382), could be substituted with any other bulky hydrophobic amino acid residue for LAMP-1 to exclusively localize in lysosomes. In order to test this hypothesis, we compared subcellular distribution of four substitution mutants with phenylalanine, leucine, methionine and valine at the COOH-terminus (termed I382F, I382L, I382M and I382V, respectively) with that of wild-type (WT)-LAMP-1. Double-labelled immunofluorescence analyses showed that these substitution mutants were localized as significantly to late endocytic organelles as WT-LAMP-1. However, the quantitative subcellular fractionation study revealed different distribution of WT-LAMP-1 and these four COOH-terminal mutants in late endosomes and dense secondary lysosomes. WT-LAMP-1 was accumulated three to six times more in the dense lysosomal fraction than the four mutants. The level of WT-LAMP-1 in late endosomal fraction was comparable to those of I382F, I382M and I382V. Conversely, I382L in the late endosomal fraction was approximately three times more abundant than WT-LAMP-1. These findings define the presence of isoleucine residue at the COOH-terminus of LAMP-1 as critical in governing its efficient delivery to secondary lysosomes and its ratio of lysosomes to late endosomes