Publications by authors named "Hirofumi Doi"

Background: This study aimed to investigate the association between the drainage quantity of pelvic drains and postoperative complications in colorectal surgery.

Materials And Methods: This retrospective single-center study enrolled 122 colorectal surgery patients between January 2017 and December 2020. After restorative proctectomy or proctocolectomy with gastrointestinal anastomosis, a continuous, low-pressure suction pelvic drain was placed and its contents measured.

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Background: Acute ischemic stroke (AIS) is a serious cause of mortality and disability. AIS is a serious cause of mortality and disability. Early diagnosis of atherosclerosis, which is the major cause of AIS, allows therapeutic intervention before the onset, leading to prevention of AIS.

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The prognosis of unresectable gastric cancer remains poor. Multidisciplinary treatment of unresectable gastric cancer is, therefore, thought to be essential for improving patients' outcomes. Here, we report a successful case of multidisciplinary therapy for unresectable gastric cancer.

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Nivolumab is one of the immune checkpoint inhibitors available for chemotherapy-resistant gastric cancer. There have been few reports of confirmed prominent shrinkage of the primary tumor and some reports of prolonged antitumor effect after discontinuance of the drug, but it is not universal. A 67-year-old male was admitted to our hospital and diagnosed with metastatic gastric cancer that had spread to the bilateral lobe of the liver, distant lymph nodes, and peritoneum.

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In advanced cancer patients, malignant cells invade and disseminate within normal cells and develop resistance to therapy with additional genetic mutations, which makes radical cure very difficult. Precision medicine against advanced cancer is hampered by the lack of systems aimed at multiple target molecules within multiple loci. Here, we report the development of a versatile diagnostic and therapeutic system for advanced cancer, named the Cupid and Psyche system.

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Epiregulin (EPR) is a ligand of the epidermal growth factor (EGF) family that upon binding to its epidermal growth factor receptor (EGFR) stimulates proliferative signaling, especially in colon cancer cells. Here, we describe the three-dimensional structure of the EPR antibody (the 9E5(Fab) fragment) in the presence and absence of EPR. Among the six complementarity-determining regions (CDRs), CDR1-3 in the light chain and CDR2 in the heavy chain predominantly recognize EPR.

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Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps).

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For a multistep pre-targeting method using antibodies, a streptavidin mutant with low immunogenicity, termed low immunogenic streptavidin mutant No. 314 (LISA-314), was produced previously as a drug delivery tool. However, endogenous biotins (BTNs) with high affinity (Kd < 10(-10) M) for the binding pocket of LISA-314 prevents access of exogenous BTN-labelled anticancer drugs.

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The streptavidin/biotin interaction has been widely used as a useful tool in research fields. For application to a pre-targeting system, we previously developed a streptavidin mutant that binds to an iminobiotin analog while abolishing affinity for natural biocytin. Here, we design a bivalent iminobiotin analog that shows 1000-fold higher affinity than before, and determine its crystal structure complexed with the mutant protein.

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We previously created a low-immunogenic core streptavidin mutant No. 314 (LISA-314) by replacing six amino-acid residues for use as a delivery tool for an antibody multistep pre-targeting process (Yumura et al., Protein Sci.

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Growth factors are implicated in several processes essential for cancer progression. Specifically, epidermal growth factor (EGF) family members, including epiregulin (EREG), are important prognostic factors in many epithelial cancers, and treatments targeting these molecules have recently become available. Here, we constructed and expressed humanized anti-EREG antibodies by variable domain resurfacing based on the three-dimensional (3D) structure of the Fv fragment.

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Cyclin-dependent kinase 5 (Cdk5) is a brain-specific membrane-bound protein kinase that is activated by binding to the p35 or p39 activator. Previous studies have focused on p35-Cdk5, and little is known regarding p39-Cdk5. The lack of functional understanding of p39-Cdk5 is due, in part, to the labile property of p39-Cdk5, which dissociates and loses kinase activity in nonionic detergent conditions.

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Hetero- and homodimerization of 14-3-3 proteins demonstrate distinctive functions in mammals and plants. Trypanosoma brucei 14-3-3I and II (Tb14-3-3I and II) play pivotal roles in motility, cytokinesis and the cell cycle; however, the significance and the mechanism of Tb14-3-3 dimerization are remained to be elucidated. We found that ectopically expressed epitope-tagged Tb14-3-3I and II proteins formed hetero- and homodimers with endogenous Tb14-3-3I and II proteins.

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The defining property of core streptavidin (cSA) is not only its high binding affinity for biotin but also its pronounced thermal and chemical stability. Although potential applications of these properties including therapeutic methods have prompted much biological research, the high immunogenicity of this bacterial protein is a key obstacle to its clinical use. To this end, we have successfully constructed hypoimmunogenic cSA muteins in a previous report.

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The posttranslational regulation of mammalian clock proteins has been assigned a time-keeping function, but seems to have more essential roles. Here we show that c-Jun N-terminal kinase (JNK), identified by inhibitor screening of BMAL1 phosphorylation at Ser 520/Thr 527/Ser 592, confers dynamic regulation on the clock. Knockdown of JNK1 and JNK2 abrogates BMAL1 phosphorylation and lengthens circadian period in fibroblasts.

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We found a novel protein-protein interaction between ubiquitin-specific protease 15 (USP15) and skeletal muscle LIM protein 1 (SLIM1): USP15 and SLIM1 directly bound under cell-free conditions and co-immunoprecipitated from the lysates of the cells, where they were co-expressed; and USP15 deubiquitinated SLIM1, resulting in the increase of protein levels of SLIM1. Because SLIM1 is strongly implicated in the pathogenesis of myopathies and cardiomyopathies, we generated transgenic (TG) mice with cardiac-specific overexpression of human USP15. Heart weight to body weight ratios and mRNA levels of fetal gene markers in the heart were significantly higher in USP15-TG mice than in wild-type (WT) mice.

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Cyclin-dependent kinase 5 (Cdk5) is a proline-directed Ser/Thr kinase that plays important roles in various neuronal activities, including neuronal migration, synaptic activity, and neuronal cell death. Cdk5 is activated by association with a neuron-specific activator, p35 or its isoform p39, but little is known about the kinase activity of Cdk5--p39. In fact, kinase-active Cdk5--p39 was not prepared from rat brain extracts nor from HEK293 cells expressing Cdk5 and p39 by immunoprecipitation in the presence of non-ionic detergent, under conditions with which active Cdk5--p35 could be isolated.

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Our research activity of making the lexicon of relatively short oligopeptides has been one of the first steps to view the world of proteome from the perspective of oligopeptides. We propose a new method for the prediction of protein function, especially GeneOntology terms (GO terms), based on statistical characteristics of oligopeptides as an application of the lexicon. In the lexicon, a known function of a protein is inherited to its oligopeptides, and the correspondence between oligopeptides and the function is calculated in the whole proteins.

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Cathepsin A (CathA) is a lysosomal serine carboxypeptidase that exhibits homology and structural similarity to the yeast and wheat serine carboxypeptidases (CPY and CPW) belonging to the alpha/beta-hydrolase fold family. Human CathA (hCathA) and CPW have been demonstrated to be inhibited by a proteasome (threonine protease) inhibitor, lactacystin, and its active derivative, omuralide (clasto-lactacystin beta-lactone), as well as chymostatin. A hCathA/omuralide complex model constructed on the basis of the X-ray crystal structures of the CPW/chymostatin complex and the yeast proteasome beta-subunit (beta5/PRE2)/omuralide one predicted that the conformation of omuralide in the active-site cleft of proteasome beta5/PRE2 should be very similar to that of chymostatin at the S1 catalytic subsites in the hCathA- and CPW-complexes.

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Fabry disease comprises classic and variant phenotypes. The former needs early enzyme replacement therapy, and galactose infusion is effective for some variant cases. Attempts of early diagnosis before manifestations appear will begin in the near future.

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Melanin-concentrating hormone (MCH) receptor 1 (MCH1R) is a class A G protein-coupled receptor. The MCH system has been linked to a variety of physiological functions, including the regulation of feeding and energy metabolism. We recently reported the importance of a dibasic motif in the membrane-proximal C-terminal region for MCH1R function.

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The actions of peptidase inhibitors derived from Streptomycete on human cathepsin A (hCath A), yeast carboxypeptidase Y (CPY), and wheat carboxypeptidase II (CPW) were analyzed comparatively. Lactacystin and omuralide (clasto-lactacystin beta-lactone), well-known cytoplasmic proteasome inhibitors, both had a potent and non-competitive inhibitory effect on these homologous serine carboxypeptidases, although they inhibited CPW and hCath A more effectively than CPY in vitro. Ebelactone B exhibited a mixed non-competitive inhibitory effect and selectivity for CPY.

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Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that plays a key role in food intake. It acts through two G protein-coupled receptors (GPCRs), MCH1R and MCH2R, of which MCH1R is the primary regulator of food intake. We have previously reported that N-linked glycosylation of the extracellular domain of MCH1R is necessary for cell surface expression and signal transduction.

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Alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency (Schindler/Kanzaki disease) is a clinically and pathologically heterogeneous genetic disease with a wide spectrum including an early onset neuroaxonal dystrophy (Schindler disease) and late onset angiokeratoma corporis diffusum (Kanzaki disease). In alpha-NAGA deficiency, there are discrepancies between the genotype and phenotype, and also between urinary excretion products (sialyl glycoconjugates) and a theoretical accumulated material (Tn-antigen; Gal NAcalpha1-O-Ser/Thr) resulting from a defect in alpha-NAGA. As for the former issue, previously reported genetic, biochemical and pathological data raise the question whether or not E325K mutation found in Schindler disease patients really leads to the severe phenotype of alpha-NAGA deficiency.

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