467 research outputs found

    Identification of a Xenopus glutamine synthetase gene abundantly expressed in the embryonic nervous system but not in adult brain

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    AbstractWe used a PCR-based subtraction cloning procedure with concanavalin A-treated and -untreated animal caps from stage 9 Xenopus embryos to search for genes up-regulated during early neural development. One such gene was found to encode a protein homologous to several known glutamine synthetases, and we named it xGS. Molecular hybridization studies revealed that xGS mRNA is maternally transmitted and abundantly expressed in neuroectoderm-derived tissues during the gastrula and neurula stages. The expression of xGS mRNA in the nervous system continues until the larval stages, but declines thereafter and becomes undetectable in adult brain. Considering its metabolic activity and potential neuroprotective effect against the neurotoxic substances such as glutamate and ammonia, the glutamine synthetase may play an important role in the early stages of vertebrate neural development

    Abundant expression of the membrane-anchored protease-regulator RECK in the anterior pituitary gland and its implication in the growth hormone/insulin-like growth factor 1 axis in mice

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    The tumor suppressor gene Reversion-inducing cysteine-rich protein with Kazal motifs (Reck) encodes a membrane-anchored protease regulator expressed in multiple tissues in mouse embryos and is essential for embryonic development. In postnatal mice, however, physiological roles for the RECK protein remain unclear. We found in this study that Reck is abundantly expressed in growth hormone (GH)-producing cells (somatotrophs) in the anterior pituitary gland (AP). We also found that two types of viable Reck mutant mice, one with reduced RECK expression (Hypo mice) and the other with induced Reck deficiency from 10 days after birth (iKO mice treated with tamoxifen), exhibit common phenotypes including decreases in body size and plasma levels of insulin-like growth factor-1 (IGF1). To gain insights into the function of RECK in the AP, we characterized several somatotroph-associated molecules in the AP of these mice. Immunoreactivity of GH was greatly reduced in tamoxifen-treated iKO mice; in these mice, two membrane receptors involved in the stimulation of GH secretion [growth hormone secretagogue receptor (GHSR) and growth hormone releasing hormone receptor (GHRHR)] were decreased, however, their mRNAs were increased. Decrease in GHSR immunoreactivity and concomitant increase in its mRNA were also found in the other mutant line, Hypo. Furthermore, reduced immunoreactivity of growth hormone receptor (GHR) and concomitant increase in its mRNA was also found in the liver of Hypo mice. These results raise the possibility that RECK supports proper functioning of the GH/IGF1 axis in mice, thereby affecting their growth and metabolism

    Tissue factor pathway inhibitor-2 suppresses the production of active matrix metalloproteinase-2 and is down-regulated in cells harboring activated ras oncogenes

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    AbstractA human placenta cDNA expression library was screened for genes inducing flat reversion when transfected into a v-K-ras-transformed NIH3T3 cell line, DT. One such gene was found to encode a Kunitz-type serine protease inhibitor, tissue factor pathway inhibitor-2 (TFPI-2). While the TFPI-2 mRNA can be detected in normal human fibroblasts (MRC-5), it is down-regulated in MRC-5 cells expressing an activated H-ras oncogene and in the human fibrosarcoma cell line, HT1080. Restored expression of the TFPI-2 gene in HT1080 cells resulted in the suppression of matrix invasion activity in vitro with concomitant decrease in the relative amount of active matrix metalloproteinase-2 secreted from the cells. When DT cells were cultured in the presence of conditioned medium and extracellular matrix prepared from TFPI-2-transfected HT1080 cells, increased attachment and flat reversion were observed. These results suggest that TFPI-2 may be required for the maintenance of the integrity of extracellular matrix in normal tissues and its down-regulation as a result of oncogene activation may contribute to the malignant phenotypes of tumor cells

    Beyond Real-world Benchmark Datasets: An Empirical Study of Node Classification with GNNs

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    Graph Neural Networks (GNNs) have achieved great success on a node classification task. Despite the broad interest in developing and evaluating GNNs, they have been assessed with limited benchmark datasets. As a result, the existing evaluation of GNNs lacks fine-grained analysis from various characteristics of graphs. Motivated by this, we conduct extensive experiments with a synthetic graph generator that can generate graphs having controlled characteristics for fine-grained analysis. Our empirical studies clarify the strengths and weaknesses of GNNs from four major characteristics of real-world graphs with class labels of nodes, i.e., 1) class size distributions (balanced vs. imbalanced), 2) edge connection proportions between classes (homophilic vs. heterophilic), 3) attribute values (biased vs. random), and 4) graph sizes (small vs. large). In addition, to foster future research on GNNs, we publicly release our codebase that allows users to evaluate various GNNs with various graphs. We hope this work offers interesting insights for future research.Comment: Accepted to NeurIPS 2022 Datasets and Benchmarks Track. 21 pages, 15 figure

    コンピュータ カツヨウ キョウイク ナイヨウ ノ セイカ ト ヒョウカ

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    In a part of the curriculum the students of two classes learned how to manage a computer software,“EXCEL",with which they calculated their daily calorie intake and expenditure. The questionnaire to the students to evaluate the computer-aided education revealed as follows: (1) Many students felt that learning “EXCEL" was useful to improve their skill. (2) Evaluation of educational achievement was poor in improving knowledge and skill of the students by the method applied herein. (3) We must intensively revise the method to achieve educational effect

    Mechanical performances of finger jointed cross laminated timber (CLT)

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    Based on the idea of first producing small-size CLT panels and afterward connecting them using finger joints to make larger CLT panels, finger-jointed CLT test specimens were fabricated by setting experimental parameters such as the kind of finger joint (large or normal), the combination of finger joint strength (strong–strong, or weak–weak) and the number of layers, and ply (3L3P, 5L5P, and 5L7P). Destructive tests subjected to out-of-plane as well as in-plane bending and shear, and axial compression load were performed. To judge the mechanical performance of the finger-jointed CLT panels, the lower 5% strength value evaluated from the destructive tests data were used for comparison with the characteristic strength value of CLT products assigned by the Ministry of Land, Infrastructure, Transport and Tourism in Japan (MLIT). On the other hand, the lower 50% stiffness value evaluated from the destructive test data was used for comparison with the design stiffness values proposed by commercial sectors. Most of the tested finger-jointed CLT groups satisfied the requirements for the characteristic strength values although there were a few exceptional cases in the weak–weak groups. All of the tested finger jointed CLT groups satisfied the proposed design stiffness values
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