Publications by authors named "Megumi Shibata"

Objectives: Phosphate (Pi) induces differentiation of arterial smooth muscle cells to the osteoblastic phenotype by inducing the type III Na-dependent Pi transporter Pit-1/solute carrier family member 1. This induction can contribute to arterial calcification, but precisely how Pi stress acts on the vascular wall remains unclear. We investigated the role of extracellular Pi in inducing microstructural changes in the arterial wall.

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  • Proglucagon-derived peptides (PDGPs) like glucagon and GLP-1 play a role in managing lipid metabolism in various body tissues, but their specific function in high-fat diet (HFD) scenarios is not fully clear.
  • In this study, researchers compared PGDP-deficient mice (GCGKO) to control mice after both were fed an HFD for 7 days, focusing on differences in lipid metabolism in the liver, adipose tissue, and intestine.
  • Results showed that GCGKO mice had lower levels of genes involved in fat oxidation, reduced fatty acids and triglyceride content in the liver and fat tissue, and increased fecal cholesterol, suggesting that lacking PGDP may protect against developing fatty
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The tau protein is a microtubule-associated protein that promotes microtubule stabilization. The phosphorylation of the tau protein has been linked to its dissociation from microtubules. Here, we examined the relationship between neuronal depolarization activity and tau protein phosphorylation by employing model systems in culture as well as in vivo.

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Sleep apnea is regarded as an important risk factor in the pathogenesis of Alzheimer disease (AD). Chronic intermittent hypoxia treatment (IHT) given during the sleep period of the circadian cycle in experimental animals is a well-established sleep apnea model. Here we report that transient IHT for 4 days on AD model mice causes Aβ overproduction 2 months after IHT presumably via upregulation of synaptic BACE1, side-by-side with tau hyperphosphorylation.

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We investigated the impact of the Coronavirus disease 2019 (COVID-19) pandemic on the management of endocrine and metabolic disorders in Japan. We conducted a cross-sectional nationwide questionnaire survey targeting board-certified endocrinologists under the auspices of the Japan Endocrine Society. The questionnaire consisted of multiple-choice questions and open-ended responses.

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Objectives: Type 1 diabetes mellitus (T1DM) patients with diabetic kidney disease-induced kidney failure have a significantly impaired quality of life (QOL), resulting in a high level of physical, mental, and social anxiety. In this study, we evaluated the QOL of T1DM patients on the list for pancreas transplantation (PTx) at their registration, and determined whether PTx improved their QOL.

Methods: There were 58 patients (men/women, 22/36; mean age, 42.

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Kidney transplant recipients are patients at high risk for coronavirus disease 2019 (COVID-19) due to being on immunosuppressive therapy. B cell depletion therapy, including rituximab, is an important strategy for ABO-incompatible transplants. However, knowledge about the effect of B cell depletion therapy on COVID-19 is lacking.

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  • Glucagon, secreted by pancreatic α-cells, is crucial for amino acid metabolism in the liver, and its absence leads to increased amino acid levels and changes in muscle fiber type in mice.
  • The study analyzed muscle tissues from GCGKO mice (lacking glucagon action) and found muscle hypertrophy and a shift from type IIA to type IIB fibers, indicating changes in muscle composition.
  • Results suggest that reduced glucagon action raises certain amino acid concentrations in muscle, leading to increased muscle weight and changes similar to those seen in high-protein diets.
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Background: To perform more pancreas transplantation (PTx), our center sometimes performs pancreas transplantation for candidates ranked sixth place or lower. In this study, we analyzed the outcomes of PTx performed in our center to compare the outcomes of higher- and lower-ranked candidates.

Methods: Seventy-two cases in which PTx was performed at our center were divided into 2 groups according to the candidate's rank.

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Background: Pure red cell aplasia (PRCA) is a hematological disorder characterized by anemia with severe reticulocytopenia caused by a marked reduction in erythroid precursors in the bone marrow. PRCA is known to be associated with pregnancy, but thymoma-associated PRCA during pregnancy is very rare, and its successful management has not been reported.

Case Presentation: A 37-year-old primiparous woman with severe anemia was referred to our center at 27 weeks' gestation.

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Objectives: Delta C-peptide derived by the glucagon stimulation test is a reliable value for the evaluation of the pancreatic endocrine function after pancreas transplantation. We examined the associations between delta C-peptide as pancreatic graft endocrine function and donor background factors.

Methods: Sixty-five cases of pancreatic transplantation from brain-dead donors, which were performed in our facility, were enrolled in this study.

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Maintenance of postoperative graft flow is important in pancreas transplantation. In Japan, reconstruction of the common hepatic artery is performed primarily to increase perfusion in the pancreatic head. We investigated the effects of common hepatic artery reconstruction on patient and graft survival and endocrine functions.

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Aims: Although skin manifestations are common in diabetic patients, its characteristics are poorly identified. This study explored the differentiation process of keratinocytes in type 2 diabetes mellitus (T2DM) in vivo.

Methods: Back skin of T2DM model KKAy/TaJcl mice (KKAy) and C57BL/6JJcl mice (control) aged 8 and 12 weeks was used.

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(1) Background: Protein stimulates the secretion of glucagon (GCG), which can affect glucose metabolism. This study aimed to analyze the metabolic effect of a high-protein diet (HPD) in the presence or absence of proglucagon-derived peptides, including GCG and GLP-1. (2) Methods: The response to HPD feeding for 7 days was analyzed in mice deficient in proglucagon-derived peptides (GCGKO).

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Oxidative stress is a well-known inducer of two major neurodegenerative pathways, neuronal cell death and neurite degeneration. We previously reported that reactive oxygen species (ROS) generated by NADPH oxidases induces EGFR-dependent phosphorylation and activation of ZNRF1 ubiquitin ligase in neurons, which promotes neuronal cell death and neurite degeneration. While these findings provide a potential therapeutic avenue for neurodegeneration, a deeper understanding of the molecular mechanisms of this pathway have emerged as key points of interest.

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We report the case of a 36-year-old woman with spontaneously conceived heterotopic pregnancy with abdominal pregnancy. She visited the hospital at 5 weeks and 4 days of gestation and transvaginal ultrasonography revealed a normal intrauterine pregnancy. Two days later, she was urgently transported to the hospital due to extreme abdominal pain.

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  • Low birth weight in Japan has slightly risen, and the link between maternal birth weight and pregnancy outcomes is not well understood.
  • A study analyzed data from 944 women, categorizing them by birth weight, to assess the risks of low birth weight and small-for-gestational-age infants, as well as hypertensive disorders during pregnancy.
  • Results showed women with lower birth weights had a higher risk of having low birth weight and small-for-gestational-age infants, but no significant link was found for hypertensive disorders or preterm birth.
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The small noncoding vault RNA (vtRNA) is a component of the vault complex, a ribonucleoprotein complex found in most eukaryotes. Emerging evidence suggests that vtRNAs may be involved in the regulation of a variety of cellular functions when unassociated with the vault complex. Here, we demonstrate a novel role for vtRNA in synaptogenesis.

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  • Mislocalization of the TDP-43 protein in neurons is a key feature in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), but its role in disease mechanisms is not well understood.
  • Researchers hypothesized that TDP-43's failure to transport mRNA to axons could contribute to neurodegeneration and found that TDP-43 binds to and helps transport ribosomal protein (RP) mRNAs necessary for local protein synthesis in axons.
  • Their study demonstrated that reduced levels of RP mRNAs in ALS cases with TDP-43 pathology could impair the function of axonal ribosomes, revealing a crucial role for TDP-43 in maintaining axonal health and its relation to neuro
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  • The study aimed to assess how many pregnant women would opt for prenatal genetic testing (GT) if given sufficient information early in their pregnancy.
  • In a sample of 5700 pregnant women, about 34.8% chose to undergo some form of GT, with older women (especially those ≥40 years) showing a higher preference for genetic counseling (GC) and testing compared to younger women.
  • Despite providing thorough information, around 50% of women with advanced maternal age still chose not to undergo GT, indicating that even well-informed patients may have reservations about testing options.
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Osteoporosis patients with chronic kidney disease (CKD) are becoming common in our superaging society. Renal dysfunction causes phosphorus accumulation in the circulating plasma and leads to the development of CKD-mineral bone disorder (MBD). We have previously reported that type III Pi transporter-overexpressing transgenic (Pit-1 TG) rats manifest phosphate (Pi)-dependent podocyte injury.

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Objectives: The aim of this study was to compare the outcomes of pancreatic transplantation from pediatric donors younger than 15 years of age to the outcomes of pancreatic transplantation from adult donors.

Methods: Sixty patients underwent pancreatic transplantation in our facility from August 2012 to June 2019. These patients were divided into two groups according to the age of the donor: Cases in which the donor was younger than 15 years of age were classified into the PD group ( = 7), while those in which the donor was older than 15 years of age were classified into the AD group ( = 53).

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Aims: The aim of this study is to investigate the effects of a low-carbohydrate staple food (i.e., low-carbohydrate bread) on glucose and lipid metabolism and pancreatic and enteroendocrine hormone secretion in comparison with meals containing normal-carbohydrate bread, without consideration of the carbohydrate content of the side dishes.

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Long-term exposure to a high starch, low-protein diet (HSTD) induces body weight gain and hyperinsulinemia concomitantly with an increase in β-cell mass (BCM) and pancreatic islets number in mice; however, the effect of short-term exposure to HSTD on BCM and islet number has not been elucidated. In the present study, we investigated changes in body weight, plasma insulin levels, BCM and islet number in mice fed HSTD for 5 weeks followed by normal chow (NC) for 2 weeks. BCM and islet number were increased in mice fed HSTD for 5 weeks compared with those in mice fed NC.

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Objective: Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is an immune-mediated condition that can affect almost any organ. We investigated the association between IgG4-RD and the main characteristics of Graves' disease (GD) at the time of diagnosis. Additionally, we evaluated whether serum IgG4 levels change during treatment.

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