Inbreeding ratio and genetic relationships among strains of the Western clawed frog, Xenopus tropicalis

The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts

N-Cadherin Expressed on Malignant T Cell Lymphoma Cells is Functional, and Promotes Heterotypic Adhesion Between the Lymphoma Cells and Mesenchymal Cells Expressing N-Cadherin

Cadherins are Ca2+-dependent cell–cell adhesion molecules, and are involved in the formation and maintenance of the organocellular architecture. Using a combination of molecular biologic and biochemical methods, we analyzed cadherins expressed on cultured human malignant lymphoma cell lines (adult T cell lymphomas, human T cell leukemia virus type 1-negative T cell lines, and thymus-derived lymphoma cell lines), and obtained evidence that N-cadherin is the major cadherin expressed on these cells. These cells were found to form cell aggregates in a Ca2+-dependent manner, and more importantly to coaggregate and adhere with cells expressing N-cadherin, suggesting that N-cadherin on lymphoma cells is functionally active. Therefore, N-cadherin expressed on lymphoma cells could underlie the frequent invasion of these cells into the mesenchymal tissue in the skin and the central nervous system

Evaluation of Seismic Safety of a Large Caisson Structure

Some centrifugal shaking tests were carried out to clarify the mechanism of seismic interaction between a large caisson foundation and soil layers. Based on the test data, two-dimensional seismic effective stress FE analysis was applied, followed by verifying its applicability. Also, to clarify the flexural and shear behavior of the caisson structure members to the ultimate state and to evaluate the flexural and shear resistance, some large-scale model failure tests of poorly reinforced concrete in caisson foundation were carried out. Based on these test results above-mentioned, seismic analyses of an existing large caisson foundation to ground motion in level 2 earthquakes were carried out, adopting the above-mentioned analysis. As the results, it was concluded that the seismic safety on the caisson foundation was confirmed

Structural Basis of the Autophagy-Related LC3/Atg13 LIR Complex: Recognition and Interaction Mechanism

SummaryAutophagy is a bulk degradation pathway that removes cytosolic materials to maintain cellular homeostasis. The autophagy-related gene 13 (Atg13) and microtubule associate protein 1 light chain 3 (LC3) proteins are required for autophagosome formation. We demonstrate that each of the human LC3 isoforms (LC3A, LC3B, and LC3C) interacts with Atg13 via the LC3 interacting region (LIR) of Atg13. Using X-ray crystallography, we solved the macromolecular structures of LC3A and LC3C, along with the complex structures of the LC3 isoforms with the Atg13 LIR. Together, our structural and binding analyses reveal that the side-chain of Lys49 of LC3 acts as a gatekeeper to regulate binding of the LIR. We verified this observation by mutation of Lys49 in LC3A, which significantly reduces LC3A positive puncta formation in cultured cells. Our results suggest that specific affinity of the LC3 isoforms to the Atg13 LIR is required for proper autophagosome formation

Metastases of soft tissue sarcoma to the liver: A Historical Cohort Study from a Hospital-based Cancer Registry

Background: Hepatic metastasis of soft tissue sarcoma is rare compared to lung metastasis, and the literature is scarce. We examined the risk of hepatic metastasis according to the site of occurrence and histological type. Methods: From a Hospital-based Cancer Registry, 658 patients registered between 2007 and 2017 with soft tissue sarcomas were evaluated. The exclusion criteria were gastrointestinal stromal tumors, tumors of unknown origin, and follow-up periods of less than 1 month. SPSS 25 was used for statistical analysis. Results: The risk of hepatic metastasis was significantly higher in the retroperitoneum (HR, 5.981; 95% CI, 2.793-12.808) and leiomyosarcoma (HR, 4.303; 95% CI, 1.782-10.390). Multivariate analysis showed that the risk of hepatic metastasis as first distant metastasis was high in leiomyosarcoma (HR, 4.546; 95% CI, 2.275-9.086) and retroperitoneal onset (HR, 4.588; 95% CI, 2.280-9.231). The 2-year survival rate after hepatic metastasis was 21.7%. Conclusions: The onset of hepatic metastasis indicates a poor prognosis. However, hepatic metastasis from retroperitoneal sarcoma and leiomyosarcoma may be the first distant metastasis in some cases. For retroperitoneal sarcoma and leiomyosarcoma, additional screening for hepatic metastasis such as contrast CT should be considered during staging and follow-up after treatment.ArticleCancer medicine 17(17) : 6159-6165(2020)journal articl

Evaluation of Infliximab Effects on Gastrointestinal Bleeding in Crohn's Disease Using Double-Balloon Endoscopy

Tumor necrosis factor α plays an important role in the pathogenesis of Crohn's disease (CD). The effects of infliximab on gastrointestinal bleeding in CD have not yet been fully evaluated. Herein we describe three CD cases who presented with gastrointestinal bleeding and received infliximab treatment. In case 1, double-balloon endoscopy showed a large ulcer with several irregularly shaped ulcers in the terminal ileum; 8 weeks after infliximab administration, complete healing of all lesions was observed. In case 2, double-balloon endoscopy showed linear ulcers and mucosal edema in the jejunum and ileum; 5 weeks after infliximab administration, all lesions were decreased in size and were healed. In case 3, double-balloon endoscopy revealed ulcerations and stenosis in the terminal ileum; 12 weeks after infliximab administration, ulcer healing and an increased diameter of the ileal stenosis were observed. These three cases have been receiving ongoing infliximab maintenance therapy and are currently symptom-free. Infliximab thus appears to be useful for treatment of gastrointestinal bleeding in CD patients