Search

Background Physical or psychological stress causes functional disorders in the upper gastrointestinal tract. This study aims to elucidate the ameliorating effect of exogenous acylated ghrelin or rikkunshito, a Kampo medicine which acts as a ghrelin enhancer, on gastric dysfunction during acute restraint stress in mice. Methods Fasted and postprandial motor function of the gastric antrum was wirelessly measured using a strain gauge force transducer and solid gastric emptying was detected in mice exposed to restraint stress. Plasma corticosterone and ghrelin levels were also measured. To clarify the role of ghrelin on gastrointestinal dysfunction in mice exposed to stress, exogenous acylated ghrelin or rikkunshito was administered, then the mice were subjected to restraint stress. Key Results Mice exposed to restraint stress for 60 min exhibited delayed gastric emptying and increased plasma corticosterone levels. Gastric motility was decreased in mice exposed to restraint stress in both fasting and postprandial states. Restraint stress did not cause any change in plasma acylated ghrelin levels, but it significantly increased the plasma des-acyl ghrelin levels. Administration of acylated ghrelin or rikkunshito improved the restraint stress-induced delayed gastric emptying and decreased antral motility. Ameliorating effects of rikkunshito on stress-induced gastric dysfunction were abolished by simultaneous administration of a ghrelin receptor antagonist. Conclusions & Inferences Plasma acylated/des-acyl ghrelin imbalance was observed in acute restraint stress. Supplementation of exogenous acylated ghrelin or enhancement of endogenous ghrelin signaling may be useful in the treatment of decreased gastric function caused by stress. [ABSTRACT FROM AUTHOR]

Abstract: Recently, Sazanov’s group reported the X-ray structure of whole complex I [Nature, 465, 441 (2010)], which presented a strong clue for a “piston-like” structure as a key element in an “indirect” proton pump. We have studied the NuoL subunit which has a high sequence similarity to Na+/H+ antiporters, as do the NuoM and N subunits. We constructed 27 site-directed NuoL mutants. Our data suggest that the H+/e− stoichiometry seems to have decreased from (4H+/2e−) in the wild-type to approximately (3H+/2e−) in NuoL mutants. We propose a revised hypothesis that each of the “direct” and the “indirect” proton pumps transports 2H+ per 2e−. [ABSTRACT FROM AUTHOR]

Objective: Mesenchymal stem cells (MSC) have both self-renewal and multilineage differentiation potential, and bone marrow-derived MSC have been applied for tissue regeneration and repair. Although adipose tissue-derived MSC (ASC) have emerged as an alternative cell source, little information is available regarding the biologic difference between ASC derived from visceral and subcutaneous fat. Therefore, we aimed to compare the proliferation and gene expression profile of cultured human visceral ASC (VASC) and subcutaneous ASC (SASC), and to identify a novel gene involved in proliferation and differentiation of ASC. Materials and methods: We performed microarray analysis of cultured VASC and SASC, and investigated the role of tazarotene-induced gene 1 (TIG1), a most differentially expressed gene, in the proliferation and differentiation of ASC. Results: SASC proliferated faster than VASC for over 10 passages, and TIG1 expression was consistently up-regulated in VASC of humans, rats and mice. Overexpression of the TIG1 gene in human SASC inhibited cell proliferation, whereas knockdown of TIG1 expression by siRNA promoted cell proliferation. In addition, overexpression of the TIG1 gene in SASC enhanced their differentiation into adipocytes, and promoted up-regulation of peroxisome proliferators-activated receptor γ and CCAAT/enhancer binding protein α. On the other hand, TIG1 overexpression in SASC inhibited their differentiation into osteocytes and the expression of osteocalcin. Conclusion: TIG1 plays an important role in regulating proliferation and differentiation of ASC. [ABSTRACT FROM AUTHOR]

Coenzyme Q_{10} (which is also designated as CoQ_{10}, ubiquinone-10, UQ_{10}, CoQ, UQ or simply as Q) plays an important role in energy metabolism. For NADH-Q oxidoreductase (complex I), Ohnishi and Salerno proposed a hypothesis that the proton pump is operated by the redox-driven conformational change of a Q-binding protein, and that the bound form of semiquinone (SQ) serves as its gate [FEBS Letters 579 (2005) 45–55]. This was based on the following experimental results: (i) EPR signals of the fast-relaxing SQ anion (designated as Q_{Nf}^{ -}) are observable only in the presence of the proton electrochemical potential (Δμ_{H}^{+}); (ii) iron-sulfur cluster N2 and Q_{Nf}^{ -} are directly spin-coupled; and (iii) their center-to-center distance was calculated as 12Å, but Q_{Nf}^{ -} is only 5Å deeper than N2 perpendicularly to the membrane. After the priming reduction of Q to Q_{Nf}^{ -}, the proton pump operates only in the steps between the semiquinone anion (Q_{Nf}^{ -}) and fully reduced quinone (QH_{2}). Thus, by cycling twice for one NADH molecule, the pump transports 4H^{+} per 2e^{-}. This hypothesis predicts the following phenomena: (a) Coupled with the piericidin A sensitive NADH-DBQ or Q_{1} reductase reaction, Δμ_{H}^{+} would be established; (b) Δμ_{H}^{+} would enhance the SQ EPR signals; and (c) the dissipation of Δμ_{H}^{+} with the addition of an uncoupler would increase the rate of NADH oxidation and decrease the SQ signals. We reconstituted bovine heart complex I, which was prepared at Yoshikawa's laboratory, into proteoliposomes. Using this system, we succeeded in demonstrating that all of these phenomena actually took place. We believe that these results strongly support our hypothesis. [ABSTRACT FROM AUTHOR]

The recovery of renal function following renal ischemia was studied using rats fed for 1-, 3-, and 5-week periods with an alcoholic diet (ethanol provided 36% of total calories). Renal ischemia was produced by clamping the renal artery and vein for 20 min. Renal function was determined 24 hr after the ischemia. In the absence of ischemic insult, the renal function of rats fed with an alcoholic diet for 1, 3, and 5 weeks was not significantly different from those of nonalcoholic rats. In nonalcoholic rats, renal function (24 hr postischemia) were: glomerular filtration rate (GFR) 430.4 ± 29.6 μl/min/g KW (kidney weight), renal plasma flow rate (RPFR) 1.4 ± 0.17 ml/min/g KW, and fractional sodium excretion (FENa) 2.0 ± 0.04% (mean ± SE). Postischemic renal function of rats on 1- and 3-week alcoholic diets were essentially the same as that of the control rats. However, the 24-hr postischemic renal function of 5-week alcoholic diet rats was significantly depressed. The values were only 117.2 ± 35.2 μl/min/g KW ( p < 0.05) for GFR, 0.31 ± 0.12 ml/min/g KW ( p < 0.05) for RPFR, and 7.46 ± 3.59% for FENa. The present results demonstrate that the rat kidney subjected to prolonged alcohol ingestion was more susceptible to renal insult than a nonalcoholic kidney. [ABSTRACT FROM AUTHOR]

A 17-year-old boy with X-linked inhibitor of apoptosis (XIAP) deficiency was referred to our hospital for hematopoietic stem cell transplantation (HSCT). Before HSCT, colonoscopy revealed a stricture of the ileocecal valve with an active ulcer (Fig. a), in addition to active multiple ulcers in his large intestine (Fig. b,c). Before hematopoietic stem cell transplantation (HSCT), the ileocecal valve (arrow) was mildly stenosed with an active ulcer (a), and there were multiple active ulcers in the transverse colon (b) and sigmoid colon (c). [Extracted from the article]

Background and Aims: The prognostic impact of previous-HBV-infection (pHBV) in non-HBV-related hepatocellular carcinoma (non-HBV-related-HCC) and the prevalence, characteristics and significance of recently developed high-sensitivity HBs antigen positivity (hHBsAg+) in these patients remain unclear. We aimed to close these gaps., Methods: We retrospectively screened patients with newly diagnosed non-HBV-related-HCC (standard HBsAg-test negative) at Hokkaido University. Patients with complete clinical information and preserved serum for hHBsAg+ were included. We evaluated the prevalence, characteristics and prognostic impact of pHBV and hHBsAg+ in non-HBV-related-HCC., Results: A total of 401 non-HBV-related-HCC patients were included (288 with pHBV/113 without pHBV). In non-HBV-related-HCC, pHBV did not affect overall survival (OS). Among non-HBV-related-HCC patients with pHBV, 11.8% (34/288) were hHBsAg+ and had more advanced stages of HCC, higher AFP levels, higher vascular invasion rates, and significantly shorter OS than others (OS: 19.3 vs. 61.4 months, p = 0.012). Comparison of OS among non-HBV-related-HCC patients without pHBV (group 1), those with pHBV and without hHBsAg+ (group 2), and those with pHBV and hHBsAg+ (group 3) revealed significantly shorter OS in group 3 (19.3, 56.6 and 66.4 months in groups 1, 2 and 3, respectively; p = 0.036). Multivariate Cox regression indicated that compared with group 1, only group 3 was significantly and independently associated with shorter OS (HR: 2.044, p = 0.011). Subgroup analysis revealed that this association was particularly evident in non-HBV-related-HCC patients with non-B-non-C aetiology and advanced HCC., Conclusions: In non-HBV-related-HCC patients, hHBsAg+, not pHBV, is significantly and independently associated with poor prognosis., (© 2024 John Wiley & Sons Ltd.)

Bordetella dermonecrotic toxin (DNT) affects the biological function of host cells by activating intracellular Rho GTPases. The toxin binds to unidentified receptor(s) via 54 N-terminal amino acids, undergoes intramolecular cleavage on the C-terminal side of Arg(44) by furin or furin-like protease, and eventually enters the cytoplasm where the Rho GTPases reside. The binding to the receptor(s) and intramolecular cleavage are essential for DNT to intoxicate cells, and the 54 amino-acid binding domain encompasses the cleavage site, however, it is unclear whether these two events are related. In this study, we could narrow down the cell-binding domain to the N-terminal amino acids 2-30. The region does not contain the furin-recognition site, indicating that the cell binding and the intramolecular cleavage are independent events., (© 2011 The Societies and Blackwell Publishing Asia Pty Ltd.)

Objectives: We performed a national survey in 2003, and demonstrated characteristic features of primary sclerosing cholangitis (PSC) patients in Japan. In this study, we aimed to clarify the outcome and prognostic factors of Japanese PSC patients., Methods: Questionnaires were sent to gastroenterologists in Japan, and 391 patients with PSC were registered and enrolled in the current study. The median follow-up was 5.3 years (range 0.1-20.8 years). The cumulative incidence for survival was analysed using the Kaplan-Meier method. Univariate and multivariate analyses were performed using the Cox-proportional hazards regression model for determining prognostic variables., Results: The estimated median survival of all patients was 13.1 years, with a 5-year survival rate of 74.5%. Thirty-eight patients (9.7%) who underwent liver transplantation (LT) had a 5-year survival rate of 92.0%. Both univariate and multivariate analysis demonstrated that younger age [below 49 years old; odds ratio (OR)=1.76, 1.12-2.76, P=0.0136] and lower total bilirubin (below 3.0 mg/dl; OR=2.50, 1.60-3.89, P

We have developed a reconstituted model system to study the interaction of the Golgi membranes isolated from rabbit liver with taxol-stabilized bovine-brain microtubules without microtubule-associated proteins (MAPs). The Golgi membranes are associated with microtubules. The sheets of vesicles and the membranous tubules are observed along microtubules by direct visualization using differential-interference-contrast, dark field, or fluorescence microscopy. The monoclonal antibody against Golgi membranes suggests that the Golgi membranes, but not the contaminating vesicles, are interacting with microtubules. The degree of association is assayed quantitatively using rhodamine-labeled microtubules after separation of the complex from unbound microtubules by centrifugation upon sucrose gradient. The association is inhibited by crude MAPs, purified MAP2, or 1.0 mM ATP. However, the association neither requires the cytosol from rat liver or bovine brain nor N-ethylmaleimide, brefeldin A, or GTP-gamma-S. The association is mediated by trypsin-sensitive peripheral protein(s) on the Golgi membranes.