SummaryBackground In the international, phase III, randomized, double-blind CORRECT trial, regorafenib significantly prolonged overall survival (OS) versus placebo in patients with metastatic colorectal cancer (mCRC) that had progressed on all standard therapies. This post hoc analysis evaluated the efficacy and safety of regorafenib in Japanese and non-Japanese subpopulations in the CORRECT trial. Methods Patients were randomized 2 : 1 to regorafenib 160 mg once daily or placebo for weeks 1–3 of each 4-week cycle. The primary endpoint was OS. Outcomes were assessed using descriptive statistics. Results One hundred Japanese and 660 non-Japanese patients were randomized to regorafenib (n = 67 and n = 438) or placebo (n = 33 and n = 222). Regorafenib had a consistent OS benefit in the Japanese and non-Japanese subpopulations, with hazard ratios of 0.81 (95 % confidence interval [CI] 0.43–1.51) and 0.77 (95 % CI 0.62–0.94), respectively. Regorafenib-associated hand–foot skin reaction, hypertension, proteinuria, thrombocytopenia, and lipase elevations occurred more frequently in the Japanese subpopulation than in the non-Japanese subpopulation, but were generally manageable. Conclusion Regorafenib appears to have comparable efficacy in Japanese and non-Japanese subpopulations, with a manageable adverse-event profile, suggesting that this agent could potentially become a standard of care in patients with mCRC.Electronic supplementary materialThe online version of this article (doi:10.1007/s10637-014-0154-x) contains supplementary material, which is available to authorized users.

Chronic supraventricular tachycardia has been associated with ventricular dysfunction in humans and animals. However, this ventricular failure is poorly characterized, and the ultrastructural consequences of supraventricular tachycardia are unknown. We serially examined right and left ventricular function, endomyocardial ultrastructure, and creatine kinase activity in eight pigs at base line and again at 1, 2, and 3 wk following rapid atrial pacing. Left and right ventricular ejection fractions fell significantly from base line after 1 wk of chronic tachycardia. Three weeks of chronic pacing resulted in further deterioration in ejection fractions. Significant biventricular chamber dilatation developed and was associated with a reduction in end-diastolic wall thickness after 2 wk of tachycardia. Mitochondrial injury and diminished mitochondrial cytochrome oxidase staining of subendocardial myocytes were observed after 2 wk of tachycardia. Endomyocardial creatine kinase activity fell from control levels following 2 wk of pacing. Postmortem examination revealed a reduction in left ventricular wall thickness compared with 14 control animals. Fibrosis occurred along the subendocardial layer in paced animals, and glycogen content was also reduced. In summary, chronic supraventricular tachycardia resulted in severe biventricular pump dysfunction and chamber dilatation that were associated with ultrastructural alterations and reduced enzyme activity of the subendocardial myocytes. These ultrastructural and metabolic changes may be potential mechanisms responsible for the ventricular dysfunction and dilatation observed in this model.

In the cricket Gryllus bimaculatus, missing distal parts of the amputated leg are regenerated from the blastema, a population of dedifferentiated proliferating cells that forms at the distal tip of the leg stump. To identify molecules involved in blastema formation, comparative transcriptome analysis was performed between regenerating and normal unamputated legs. Components of JAK/STAT signalling were upregulated more than twofold in regenerating legs. To verify their involvement, Gryllus homologues of the interleukin receptor Domeless (Gb’dome), the Janus kinase Hopscotch (Gb’hop) and the transcription factor STAT (Gb’Stat) were cloned, and RNAi was performed against these genes. Gb’domeRNAi, Gb’hopRNAi and Gb’StatRNAi crickets showed defects in leg regeneration. Blastema expression of Gb’cyclinE was decreased in the Gb’StatRNAi cricket compared with that in the control. Hyperproliferation of blastema cells caused by Gb’fatRNAi or Gb’wartsRNAi was suppressed by RNAi against Gb’Stat. The results suggest that JAK/STAT signalling regulates blastema cell proliferation during leg regeneration.

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-Recently, microRNAs, involved in RNA interference, were discovered as a new gene regulation, with little is known in the filed of toxicology. In this study, a toxic dose of acetaminophen or carbon tetrachloride was administered singly to male rats, and microarry analysis using mirVana TM miRNA bioarray was performed. Partial least squares-discriminant analysis of the microarray data revealed that microRNAs expression was specifically changed by treatments at 6 hr after dosing. Furthermore, we focused on miR298 and miR370 among the microRNAs commonly affected by hepatotoxicants, because they were speculated to regulate an oxidative stress-related gene. From real-time RT-PCR analysis, microRNAs expression was suppressed by hepatotoxicants at 6 and 24 hr. Regarding acetaminophen, the decreases were found even though there were no morphological changes in the liver at 6 hr. To investigate these 2 microRNAs in more detail, we measured their expression, WST-1 for mitochondrial function and LDH release for cell collapse in primary cultured hepatocytes exposed to several concentrations of acetaminophen for 3 hr. At more than 5 mM, the microRNA expression and WST-1 decreased, whereas LDH was unchanged. Therefore, the change in microRNA expression occurred at the time when mitochondrial function was damaged prior to cell collapse. From all the above findings, we conclude that microRNAs were affected by hepatotoxicants and that the changes were found in the early phase of toxicity. Thus, our data suggest microRNAs have an important role for toxicological mechanism and we proposed that the changes in microRNA expression might be key molecules for toxicity expression.