160 research outputs found
Performance of an Intermediate-Temperature Fuel Cell Using a Proton-Conducting Sn0.9In0.1P2O7 Electrolyte
Performance of a fuel cell using Sn0.9In0.1P2O7 as the electrolyte was evaluated in the temperature range of 150–300°C under unhumidified conditions. The IR drop and electrode overpotential of the cell were measured separately by the current interruption method. The dc conductivity values of the electrolyte between 150 and 300°C , estimated from the IR drop, were comparable to the ac conductivity values (1.48×10^−1-1.95×10^−1 Scm^−1) of the electrolyte. The cell performance was improved by forming an intermediate layer consisting of Sn0.9In0.1P2O7 and Pt/C catalyst powders at the interface between the electrolyte and cathode, which significantly reduced the cathode polarization. As a result, the peak power density reached 264mWcm^−2 at 250°C using the 0.35-mm -thick electrolyte. The present fuel cell also showed high stability at low relative humidities (pH2O≈0.0075atm) and 10% CO concentration.journal articl
A proximity biotinylation-based approach to identify protein-E3 ligase interactions induced by PROTACs and molecular glues
Proteolysis-targeting chimaeras (PROTACs) as well as molecular glues such as immunomodulatory drugs (IMiDs) and indisulam are drugs that induce interactions between substrate proteins and an E3 ubiquitin ligases for targeted protein degradation. Here, we develop a workflow based on proximity-dependent biotinylation by AirID to identify drug-induced neo-substrates of the E3 ligase cereblon (CRBN). Using AirID-CRBN, we detect IMiD-dependent biotinylation of CRBN neo-substrates in vitro and identify biotinylated peptides of well-known neo-substrates by mass spectrometry with high specificity and selectivity. Additional analyses reveal ZMYM2 and ZMYM2-FGFR1 fusion protein—responsible for the 8p11 syndrome involved in acute myeloid leukaemia—as CRBN neo-substrates. Furthermore, AirID-DCAF15 and AirID-CRBN biotinylate neo-substrates targeted by indisulam and PROTACs, respectively, suggesting that this approach has the potential to serve as a general strategy for characterizing drug-inducible protein–protein interactions in cells
Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green-photodynamic eye imaging
Background To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated. Methods ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation. Results Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%. Conclusion ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection
Extracellular vesicles from senescent hepatic stellate cells promote cell viability of hepatoma cells through increasing EGF secretion from differentiated THP?1 cells
Since the discovery of the senescence-associated secretory phenotype, the role of senescent hepatic stellate cells (HSCs) in hepatocellular carcinoma (HCC) development has gained increasing attention. Similar to cytokines, extracellular vesicles (EVs) are essential for intercellular communication. However, the function of EVs derived from senescent HSCs in HCC progression has not been extensively studied. The aims of the present study were to characterize the EVs derived from senescent HSCs and determine their role in the tumor microenvironment. Cellular senescence was induced in human hepatic stellate cells (HHSteCs) with various concentrations of etoposide. Induction was confirmed using EdU staining and 53BP1 and p21 immunostaining. EVs were isolated by ultracentrifugation and analyzed by nanoparticle tracking analysis. Multiplex immunoassays were used to compare the levels of growth factors secreted from hepatoma cell lines and macrophage cells pretreated with EVs derived from senescent HHSteCs (senescent EVs) with those pretreated with EVs derived from normal cultured HHSteCs (normal EVs). Treatment with 25 μM etoposide for 3 days was the most effective at inducing senescence in HHSteCs. This finding was confirmed by induction of irreversible cell-cycle arrest, upregulation of 53BP1 and p21 expression, and increased SA-β-gal staining. Senescent HHSteCs released increased quantities of EV particles compared with normally cultured HHSteCs. Multiplex analysis revealed that there was no difference between hepatoma cell lines treated with normal EVs and those treated with senescent EVs in growth factor secretion. In contrast, the secretion of epidermal growth factor (EGF) was increased by macrophage cells treated with senescent EVs compared with those treated with normal EVs. Furthermore, senescent EVs did not affect the viability of hepatoma cells but increased the viability of hepatoma cells co-cultured with macrophage cells. In conclusion, the release of EVs from senescent HSCs was higher compared with normal HSCs. Furthermore, senescent EVs promoted HCC development by upregulating EGF secretion from macrophages
Thyroid autoantibodies at baseline predict longer survival in non-small cell lung cancer patients treated with anti-programmed cell death-1 blockade: a prospective study
The presence of anti-thyroid antibodies (ATAs) is a biomarker for the development of thyroid dysfunction induced by anti-programmed cell death-1 antibodies (PD-1-Abs). While patients with thyroid dysfunction reportedly showed better overall survival (OS), it remains unknown if ATAs at baseline can predict OS. Therefore, in this study, we examined the association of ATAs at baseline with OS in non-small cell lung cancer (NSCLC) patients with different levels of programmed cell death-1 ligand 1 (PD-L1) positivity associated with PD-1-Ab treatment efficacy. A total of 81 NSCLC patients treated with PD-1-Abs were evaluated for ATAs at baseline and prospectively for OS. Among the 81 patients, 49 and 32 patients had ≥50% (group A) and <50% (group B) PD-L1 positivity, respectively. Median OS did not differ significantly between patients with (n = 13) and without (n = 36) ATAs at baseline in group A. In contrast, median OS was significantly longer in patients with (n = 10) versus without (n = 22) ATAs at baseline in group B (not reached vs 378 days, respectively; 95% CI, 182 to 574 days, p = 0.049). These findings suggest that the presence of ATAs at baseline is a biomarker to predict better treatment efficacy of PD-1-Abs in NSCLC patients with low PD-L1 positivity, while the difference in OS in those with high PD-L1 positivity may be masked by increased tumor expression of PD-L1.departmental bulletin pape
GABA Type B Receptor Signaling in Proopiomelanocortin Neurons Protects Against Obesity, Insulin Resistance, and Hypothalamic Inflammation in Male Mice on a High-Fat Diet
There is evidence suggesting that the GABA system in the arcuate nucleus, where orexigenic neuropeptide Y and agouti-related peptide as well as anorexigenic proopiomelanocortin (POMC) are expressed, plays an important role in energy balance. In this study, we generated POMC-specific GABABreceptor-deficient [knock-out (KO)] mice. Male KO mice on a high-fat diet (HFD) showed mild increases in body weight (BW) at the age of 9 weeks compared to wild-type (WT) mice, and the differences remained significant until 16 weeks old. However, there was no difference in BW in females between genotypes. While food intake was similar between genotypes, oxygen consumption was significantly decreased in the male KO mice. The insulin tolerance test revealed that the male KO mice were less insulin sensitive compared to WT mice at the age of 8 weeks, when there was no significant difference in BW between genotypes. Despite increased BW, POMC mRNA expression in the arcuate nucleus was significantly decreased in the KO mice compared to WT mice at the age of 16 weeks. Furthermore, the expression of TNFα as well as IL-6, proinflammatory markers in the hypothalamus, was significantly increased in the KO mice on a HFD compared to WT mice. This demonstrates that the deletion of GABABreceptors in POMC neurons in the male mice on a HFD results in obesity, insulin resistance, and hypothalamic inflammation. Furthermore, the decreased POMC expression in the obese KO mice suggests that the regulation of POMC expression through GABABreceptors is essential for proper energy balance.</jats:p
Anti-hepatitis C virus activity of geranylgeranylacetone treatment in hepatitis C-infected patients
Background. Geranylgeranylacetone (GGA), which is an isoprenoid compound, has been used orally as an antiulcer drug inJapan. GGA induces antiviral gene expression by stimulating the formation of interferon-stimulated gene factor 3 in humanhepatoma cells. This study verified the anti-hepatitis C virus (HCV) activity of GGA in chronic hepatitis C-infected patients.Methods. The present prospective study included 20 consecutive anti-HCV antibody-positive, HCV-genotype 1b, and chronicgastritis patients who visited Nagasaki University Hospital between January 1999 and December 1999. GGA (150 mg per day,which is the dose generally used for chronic gastritis) was taken orally for four weeks. We evaluated HCV-RNA titers and otherclinical parameters at pretreatment, posttreatment, and at the endpoint of the study. Pretreatment was the beginning point ofGGA treatment. Posttreatment was the termination point of GGA treatment. The endpoint was the point four weeks after theposttreatment point.Results. All patients completed four weeks of GGA treatment and four weeks of observation. HCV-RNA titers at postpointwere not significantly diminished compared to those at pretreatment. However, HCV-RNA titers were significantly diminishedat endtreatment compared to pretreatment. Unfortunately, we did not observe a case with no titer of HCV-RNA. Alanineaminotransferase values and other parameters were not affected by GGA treatment.Conclusion. GGA has anti-HCV activities in chronic hepatitis C-infected patients. In the future, it will be necessary to examinethe clinical effectiveness of the combination of treatment with both GGA and interferon in HCV patients
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Initiation of Genome Instability and Preneoplastic Processes through Loss of Fhit Expression
Genomic instability drives tumorigenesis, but how it is initiated in sporadic neoplasias is unknown. In early preneoplasias, alterations at chromosome fragile sites arise due to DNA replication stress. A frequent, perhaps earliest, genetic alteration in preneoplasias is deletion within the fragile FRA3B/FHIT locus, leading to loss of Fhit protein expression. Because common chromosome fragile sites are exquisitely sensitive to replication stress, it has been proposed that their clonal alterations in cancer cells are due to stress sensitivity rather than to a selective advantage imparted by loss of expression of fragile gene products. Here, we show in normal, transformed, and cancer-derived cell lines that Fhit-depletion causes replication stress-induced DNA double-strand breaks. Using DNA combing, we observed a defect in replication fork progression in Fhit-deficient cells that stemmed primarily from fork stalling and collapse. The likely mechanism for the role of Fhit in replication fork progression is through regulation of Thymidine kinase 1 expression and thymidine triphosphate pool levels; notably, restoration of nucleotide balance rescued DNA replication defects and suppressed DNA breakage in Fhit-deficient cells. Depletion of Fhit did not activate the DNA damage response nor cause cell cycle arrest, allowing continued cell proliferation and ongoing chromosomal instability. This finding was in accord with in vivo studies, as Fhit knockout mouse tissue showed no evidence of cell cycle arrest or senescence yet exhibited numerous somatic DNA copy number aberrations at replication stress-sensitive loci. Furthermore, cells established from Fhit knockout tissue showed rapid immortalization and selection of DNA deletions and amplifications, including amplification of the Mdm2 gene, suggesting that Fhit loss-induced genome instability facilitates transformation. We propose that loss of Fhit expression in precancerous lesions is the first step in the initiation of genomic instability, linking alterations at common fragile sites to the origin of genome instability
Interferon-alpha-induced mTOR activation is an anti-hepatitis C virus signal via the phosphatidylinositol 3-kinase-Akt-independent pathway.
OBJECT: The interferon-induced Jak-STAT signal alone is not sufficient to explain all the biological effects of IFN. The PI3-K pathways have emerged as a critical additional component of IFN-induced signaling. This study attempted to clarify that relationship between IFN-induced PI3-K-Akt-mTOR activity and anti-viral action. RESULT: When the human normal hepatocyte derived cell line was treated with rapamycin (rapa) before accretion of IFN-alpha, tyrosine phosphorylation of STAT-1 was diminished. Pretreatment of rapa had an inhibitory effect on the IFN-alpha-induced expression of PKR and p48 in a dose dependent manner. Rapa inhibited the IFN-alpha inducible IFN-stimulated regulatory element luciferase activity in a dose-dependent manner. However, wortmannin, LY294002 and Akt inhibitor did not influence IFN-alpha inducible luciferase activity. To examine the effect of PI3-K-Akt-mTOR on the anti-HCV action of IFN-alpha, the full-length HCV replication system, OR6 cells were used. The pretreatment of rapa attenuated its anti-HCV replication effect in comparison to IFN-alpha alone, whereas the pretreatment with PI3-K inhibitors, wortmannin and LY294002 and Akt inhibitor did not influence IFN-induced anti-HCV replication. CONCLUSION: IFN-induced mTOR activity, independent of PI3K and Akt, is the critical factor for its anti-HCV activity. Jak independent mTOR activity involved STAT-1 phosphorylation and nuclear location, and then PKR is expressed in hepatocytes
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