Reactions of (mesityl)n(methyl)2-nsilylene complexes with pyridine-N-oxide (n = 1 and 0): formation of silanone complexes and a disiloxanyloxy complex.

Silanones (OSiR2), a heavier congener of ketones (R2CO), are highly reactive species that are readily converted to oligomeric siloxane (O-SiR2)n. Coordination of silanones to the transition-metal fragments to afford silanone-coordinated complexes is a reliable silanone stabilization method. Recently, our group reported the synthesis, structures, and reactivity of dimesityl-substituted silanone complexes Cp*(OC)2M{OSiMes2(L)}(SiMe3) (M = W, Mo, L: Lewis base, Cp*: η5-C5Me5, Mes: 2,4,6-Me3C6H2). Herein, to investigate the effect of substituents on the silicon atom during the formation of a silanone complex, we demonstrated the use of Mes and smaller Me groups. As a result, the formation of Mes(Me)-substituted silanone molybdenum complex Cp*(OC)2Mo{OSiMes(Me)(py)}(SiMe3) (5b, py: pyridine) was suggested, the silanone tungsten complex Cp*(OC)2W{OSiMes(Me)(DMAP)}(SiMe3) (4a, DMAP: 4-(dimethylamino)pyridine) was obtained, and a dimethyl-substituted disiloxanyloxy(dioxo) complex Cp*(O)2W(OSiMe2OSiMe3) (9) was formed. The reaction of 4a with PMe3 proceeded via the elimination of DMAP and migration of the SiMe3 group to the oxygen atom of the silanone ligand to afford Cp*(OC)2W(SiMes(Me)OSiMe3)(PMe3) (11a). The Mo complex Cp*(OC)2Mo(SiMes(Me)OSiMe3)(PMe3) (11b) was produced by the reaction of Cp*(OC)2Mo{SiMes(Me)}(SiMe3) (7b) with pyridine-N-oxide in the presence of PMe3.

Association Between Life Expectancy at Age 60 Years Before the COVID-19 Pandemic and Excess Mortality During the Pandemic in Aging Countries.

This cross-sectional study investigates the association between life expectancy before COVID-19 and excess mortality during the pandemic in aging countries.

Prospective study of short-term peginterferon-alpha-2a monotherapy in patients who had a virological response at 2 weeks after initiation of interferon therapy.

BACKGROUND AND AIMS: Long-term interferon (IFN) therapy is effective in eliminating hepatitis C virus (HCV). However, it carries the risk of adverse effects and reduced quality of life. To assess whether short-term IFN therapy effectively eliminates HCV, we performed a prospective pilot study of pegylated (peg)IFN-alpha-2a therapy for 8 or 24 weeks. METHODS: After excluding patients with high titers of genotype-1, 55 HCV patients received pegIFN-alpha-2a. Patients who became negative for HCV-RNA at week 2 were allocated to either an 8-week (n = 19) or 24-week (n = 15) course of IFN. We evaluated the efficacy of and tolerance to IFN therapy. RESULTS: The sustained virological response rate was excellent in the two groups (8 weeks, 89.5% [17/19]; 24 weeks, 100% [15/15], respectively,). IFN dose reduction was required in one patient of the 8-week group, but in six patients of the 24-week group (P = 0.028). Treatment was completed by all patients of the 8-week group, but discontinued in five patients of the 24-week group (P = 0.011). CONCLUSIONS: The 8-week IFN therapy is more tolerable than the 24-week therapy and had similar outcomes. Excluding the patients with high titers of genotype-1, we recommend switching to an 8-week course of pegIFN-alpha monotherapy once patients show an ultra rapid virological response at week 2 from the start of IFN therapy.

Eicosapentaenoic acid could permit maintenance of the original ribavirin dose in chronic hepatitis C virus patients during the first 12 weeks of combination therapy with pegylated interferon-alpha and ribavirin. A prospective randomized controlled trial.

OBJECTIVE: To evaluate the efficacy of eicosapentaenoic acid (EPA) against ribavirin (RBV)-associated hemolytic anemia during the first 12 weeks in chronic hepatitis C virus (HCV) combination therapy. METHODS: This study was a prospective open-label, randomized controlled trial. 100 HCV patients were randomized to either the EPA group (n = 49) or non-EPA group (n = 51) who received combination therapy with or without EPA. We compared the changes in hemoglobin level and RBV plasma concentrations at week 12 in each group with RBV dose reduction rate and performed multivariate analysis to identify independent variables associated with RBV dose reduction. RESULTS: 8 patients (17%) in the EPA group and 20 patients (29%) in the non-EPA group required RBV dose reduction, respectively. The cumulative RBV reduction rate was significantly lower in the EPA group than in the non-EPA group (p = 0.017), while the decrease of hemoglobin and RBV plasma concentrations from baseline was not significantly different. However, in the multivariate analysis, treatment with EPA showed significant variables for the reduction of RBV dose (odds ratio 3.235, p = 0.023). CONCLUSION: EPA could prevent the RBV dose reduction during the first 12 weeks in combination therapy, although further large-scale double-blind randomized controlled trials are required.

G1P3, an interferon inducible gene 6-16, is expressed in gastric cancers and inhibits mitochondrial-mediated apoptosis in gastric cancer cell line TMK-1 cell.

Expression of an interferon inducible gene 6-16, G1P3, increases not only in type I interferon-treated cells but also in human senescent fibroblasts. However, the function of 6-16 protein is unknown. Here we report that 6-16 is 34 kDa glycosylated protein and localized at mitochondria. Interestingly, 6-16 is expressed at high levels in gastric cancer cell lines and tissues. One of exceptional gastric cancer cell line, TMK-1, which do not express detectable 6-16, is sensitive to apoptosis induced by cycloheximide (CHX), 5-fluorouracil (5-FU) and serum-deprivation. Ectopic expression of 6-16 gene restored the induction of apoptosis and inhibited caspase-3 activity in TMK-1 cells. Thus 6-16 protein has anti-apoptotic function through inhibiting caspas-3. This anti-apoptotic function is expressed through inhibition of the depolarization of mitochondrial membrane potential and release of cytochrome c. By two-hybrid screening, we found that 6-16 protein interacts with calcium and integrin binding protein, CIB/KIP/Calmyrin (CIB), which interacts with presenilin 2, a protein involved in Alzheimer's disease. These protein interactions possibly play a pivotal role in the regulation of apoptosis, for which further detailed analyses are need. These results overall indicate that 6-16 protein may have function as a cell survival protein by inhibiting mitochondrial-mediated apoptosis.

Polycomb group gene mel-18 regulates early T progenitor expansion by maintaining the expression of Hes-1, a target of the Notch pathway.

Polycomb group (PcG) proteins play a role in the maintenance of cellular identity throughout many rounds of cell division through the regulation of gene expression. In this report we demonstrate that the loss of the PcG gene mel-18 impairs the expansion of the most immature T progenitor cells at a stage before the rearrangement of the TCR beta-chain gene in vivo and in vitro. This impairment of these T progenitors appears to be associated with increased susceptibility to cell death. We also show that the expression of Hes-1, one of the target genes of the Notch signaling pathway, is drastically down-regulated in early T progenitors isolated from mel-18(-/-) mice. In addition, mel-18(-/-) T precursors could not maintain the Hes-1 expression induced by Delta-like-1 in monolayer culture. Collectively, these data indicate that mel-18 contributes to the maintenance of the active state of the Hes-1 gene as a cellular memory system, thereby supporting the expansion of early T progenitors.

Polycomb group gene mel-18 modulates the self-renewal activity and cell cycle status of hematopoietic stem cells.

OBJECTIVE: Mel-18 is a member of the mammalian Polycomb group (PcG) genes. This family of genes regulates global gene expression in many biologic processes, including hematopoiesis and anterior-posterior axis formation by manipulating specific target genes, including members of the Hox family. Here, we demonstrate that mel-18 negatively regulates the self-renewal activity of hematopoietic stem cells (HSCs). MATERIALS AND METHODS: Long-term reconstitution activity was evaluated by competitive repopulating unit (CRU) and mean activity of the stem cells (MAS) assays in vivo in bone marrow cells (BMCs) derived from mel-18(-/-) and mel-18 tg mice. The expression levels of mel-18 and Hoxb4 were measured by quantitative real-time reverse transcription polymerase chain reaction. RESULTS: The Hoxb4 gene was highly expressed in HSCs derived from mel-18(-/-) mice. The observed CRUs were 3.21, 4.77, 3.32, and 1.64 CRU per 10(5) BMCs in mel-18(+/+), mel-18(-/-), C57BL/6, and mel-18 tg, respectively. MAS was 0.58, 0.18, 0.41, and 5.89 in mel-18(+/+), mel-18(-/-), C57BL/6, and mel-18 tg, respectively. The percentage in G0 phase HSCs (lin(-)flk2(-)c-Kit(+)Sca1+ cells) was increased in mel-18(-/-) mice and decreased in mel-18 tg mice. CONCLUSION: Loss or knockdown of mel-18 leads to the expression of Hoxb4, an increase in the proportion of HSCs in G0 phase, and the subsequent promotion of HSC self-renewal. These findings will enable us to develop new approaches for controlling HSC activity for hematopoietic transplantations based on ex vivo expansion of HSCs.

A case of latent primary biliary cirrhosis.

A 53-year-old housewife was the donor when living-related donor liver transplantation (LRLT) was performed in her younger sister (49-year-old) with terminal primary biliary cirrhosis (PBC). The donor's liver histology was diagnostic and compatible with PBC, although she was negative for antimitochondrial antibody (AMA: a specific marker of PBC) by immunofluorescence and had normal liver function tests as well as no symptoms of liver disease. In this patient with latent PBC, AMA was eventually detected by immunoblotting, although it was not detected by ELISA. These findings indicate that a family history of PBC is a risk factor for the development of this disease. Our patient was diagnosed before the advent of any clinical or biochemical indicators and before or at the onset of AMA positivity, so her liver histology revealed the earliest stage of PBC.

Dimerization of the Polycomb-group protein Mel-18 is regulated by PKC phosphorylation.

The Polycomb-group (Pc-G) gene products form complexes via protein-protein interactions and maintain the transcriptional repression of genes involved in embryogenesis, cell cycle, and tumorigenesis. Previously, we have shown that mouse Mel-18, a Pc-G protein, has tumor suppressor gene-like activity and negatively regulates transcription. Here, we show in vitro by pull-down assays and in vivo in transiently transfected COS-7 cells that Mel-18 forms homodimers. Deletion analysis revealed that the N-terminal RING-finger and alpha-helix domains are required for homodimer formation. In addition, we demonstrated that Mel-18 homo-dimerization is regulated by protein kinase C (PKC) and protein phosphatases, such that dephosphorylated Mel-18 is able to homo-dimerize. These results suggest that the stoichiometry and/or equilibrium of subunits of the class II Polycomb complex containing Mel-18 might be regulated by changes in phosphorylation status via the PKC signaling pathway.

Chemokine-mediated thymopoiesis is regulated by a mammalian Polycomb group gene, mel-18.

Multiple chemokines are made in the thymus, and they are likely to function in the fine control of cellular migration and regulation of thymic T cell development. Mice lacking the gene mel-18, a member of the mammalian Polycomb group genes, displayed impaired thymic T cell development. Here we report that expression of chemokine receptors CXCR4 and CCR9 are regulated by mel-18 and that CXCL12/SDF-1- and CCL25/TECK-mediated chemotactic activities are also affected by the loss of mel-18. In mel-18-/- mice, high expression of CXCR4 on CD4-CD8- cells might lead to trapping in the SDF-1 rich subcapsular region, while low expression of CCR9 on CD4+CD8+ cells might reduce cell migration to the medulla. Therefore, this member of the Polycomb group genes plays a role in thymic T cell migration and differentiation via the chemokine system.