31 research outputs found
Magnetic Phase Diagram of Ce1-xErxAl2 intermetallic compounds
The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using electrical resistivity and magnetic susceptibility measurements. The magnetic ordering temperature continuously changes with a change from antiferro-magnetism (CeAl2) to ferro-magnetism (ErAl2) appears. The magnetic ordering temperature is continuously changed as a function of Er concentration x. A spin glass behavior was found between x = 0.08 and 0.4. The magnetic phase diagram was compiled as a function of x.Embargo Period 12 month
Thermal and magnetic properties in Ce1-xErxAl2 intermetallic compounds
The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using specific heat, dc magnetization, and ac susceptibility measurements. All these compounds are isomorphic with the MgCu2 Laves phase, and the lattice parameter decreases almost linearly with the increasing Er concentration x. The dc magnetic susceptibility follows the Curie–Weiss law, and the Weiss temperature continuously changes from Θ = −24 K for x = 0 to Θ = 15 K for x = 1, indicating a change from antiferro-magnetism to ferromagnetism. Θ changes from negative to positive at around x = 0.2 where where a field-induced metamagnetic transition disappears. The magnetic ordering state continuously changes with the change in x from antiferromagnetic to ferromagnetic through a spin-glass-like behavior.Embargo Period 12 month
Defining Hypo-Methylated Regions of Stem Cell-Specific Promoters in Human iPS Cells Derived from Extra-Embryonic Amnions and Lung Fibroblasts
BACKGROUND: Human induced pluripotent stem (iPS) cells are currently used as powerful resources in regenerative medicine. During very early developmental stages, DNA methylation decreases to an overall low level at the blastocyst stage, from which embryonic stem cells are derived. Therefore, pluripotent stem cells, such as ES and iPS cells, are considered to have hypo-methylated status compared to differentiated cells. However, epigenetic mechanisms of "stemness" remain unknown in iPS cells derived from extra-embryonic and embryonic cells. METHODOLOGY/PRINCIPAL FINDINGS: We examined genome-wide DNA methylation (24,949 CpG sites covering 1,3862 genes, mostly selected from promoter regions) with six human iPS cell lines derived from human amniotic cells and fetal lung fibroblasts as well as two human ES cell lines, and eight human differentiated cell lines using Illumina's Infinium HumanMethylation27. A considerable fraction (807 sites) exhibited a distinct difference in the methylation level between the iPS/ES cells and differentiated cells, with 87.6% hyper-methylation seen in iPS/ES cells. However, a limited fraction of CpG sites with hypo-methylation was found in promoters of genes encoding transcription factors. Thus, a group of genes becomes active through a decrease of methylation in their promoters. Twenty-three genes including SOX15, SALL4, TDGF1, PPP1R16B and SOX10 as well as POU5F1 were defined as genes with hypo-methylated SS-DMR (Stem cell-Specific Differentially Methylated Region) and highly expression in iPS/ES cells. CONCLUSIONS/SIGNIFICANCE: We show that DNA methylation profile of human amniotic iPS cells as well as fibroblast iPS cells, and defined the SS-DMRs. Knowledge of epigenetic information across iPS cells derived from different cell types can be used as a signature for "stemness" and may allow us to screen for optimum iPS/ES cells and to validate and monitor iPS/ES cell derivatives for human therapeutic applications
Temporal recovery and prognostic factors for dysphagia following cardiovascular surgery: Retrospective analysis and development of predictive score
Hashida N., Hosokawa K., Kawamura A., et al. Temporal recovery and prognostic factors for dysphagia following cardiovascular surgery: Retrospective analysis and development of predictive score. Nutrition 127, 112534 (2024); https://doi.org/10.1016/j.nut.2024.112534.Objective: Dysphagia is a common complication associated with cardiovascular surgery (CVS). This study sought to better understand recovery timelines, identify risk factors, and create a prognostic model for oral intake restoration. Methods: This retrospective study included 134 patients who had CVS between April 2022 and March 2024. We assessed swallowing ability through fiberoptic endoscopic evaluation of swallowing (FEES). We randomly divided the patients’ data into a training dataset and a test dataset in a ratio of 70/30 and Kaplan–Meier analyses and Cox regression were used to assess predictors of total oral intake. We also created a scoring system using the estimated regression coefficients. Results: Most patients with CVS achieved total oral intake in 7–11 days after extubation. Over 168 h of intubation, the presence of penetration or aspiration, a poor FEES score (score > 6), and perioperative complications were significant risk factors for delayed total oral intake. The predicting score was calculated by adding the scores for each individual factor, including FEES score, penetration/aspiration, and preoperative complications. Scores ranged 0–8, categorizing patients into 0–2, 3–5, and 6–8 groups, clearly demonstrating that the higher the predicting score, the longer the time to total oral intake in both the training and the test dataset. Conclusions: All risk factors for unsuccessful or delayed total oral intake were intubation for more than a week, poor swallowing ability, and the presence of perioperative complications. The scoring system accurately predicts the restoration of oral intake following CVS
Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice
Kado T., Tomimaru Y., Kobayashi S., et al. Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice. Journal of Diabetes Research 2024, 5574968 (2024); https://doi.org/10.1155/2024/5574968.Islet transplantation (ITx) is an established and safe alternative to pancreas transplantation for type 1 diabetes mellitus (T1DM) patients. However, most ITx recipients lose insulin independence by 3 years after ITx due to early graft loss, such that multiple donors are required to achieve insulin independence. In the present study, we investigated whether skeletal myoblast cells could be beneficial for promoting angiogenesis and maintaining the differentiated phenotypes of islets. In vitro experiments showed that the myoblast cells secreted angiogenesis-related cytokines (vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and stromal-derived factor-1α (SDF-1α)), contributed to maintenance of differentiated islet phenotypes, and enhanced islet cell insulin secretion capacity. To verify these findings in vivo, we transplanted islets alone or with myoblast cells under the kidney capsule of streptozotocin-induced diabetic mice. Compared with islets alone, the group bearing islets with myoblast cells had a significantly lower average blood glucose level. Histological examination revealed that transplants with islets plus myoblast cells were associated with a significantly larger insulin-positive area and significantly higher number of CD31-positive microvessels compared to islets alone. Furthermore, islets cotransplanted with myoblast cells showed JAK-STAT signaling activation. Our results suggest two possible mechanisms underlying enhancement of islet graft function with myoblast cells cotransplantation: "indirect effects"mediated by angiogenesis and "direct effects"of myoblast cells on islets via the JAK-STAT cascade. Overall, these findings suggest that skeletal myoblast cells enhance the function of transplanted islets, implying clinical potential for a novel ITx procedure involving myoblast cells for patients with diabetes
Inhibition of microRNA-33b in humanized mice ameliorates nonalcoholic steatohepatitis
マイクロRNA-33bの阻害は非アルコール性脂肪肝炎を改善する --核酸医薬による治療応用へ--. 京都大学プレスリリース. 2023-06-13.Nonalcoholic steatohepatitis (NASH) can lead to cirrhosis and hepatocellular carcinoma in their advanced stages; however, there are currently no approved therapies. Here, we show that microRNA (miR)-33b in hepatocytes is critical for the development of NASH. miR-33b is located in the intron of sterol regulatory element–binding transcription factor 1 and is abundantly expressed in humans, but absent in rodents. miR-33b knock-in (KI) mice, which have a miR-33b sequence in the same intron of sterol regulatory element–binding transcription factor 1 as humans and express miR-33b similar to humans, exhibit NASH under high-fat diet feeding. This condition is ameliorated by hepatocyte-specific miR-33b deficiency but unaffected by macrophage-specific miR-33b deficiency. Anti-miR-33b oligonucleotide improves the phenotype of NASH in miR-33b KI mice fed a Gubra Amylin NASH diet, which induces miR-33b and worsens NASH more than a high-fat diet. Anti-miR-33b treatment reduces hepatic free cholesterol and triglyceride accumulation through up-regulation of the lipid metabolism–related target genes. Furthermore, it decreases the expression of fibrosis marker genes in cultured hepatic stellate cells. Thus, inhibition of miR-33b using nucleic acid medicine is a promising treatment for NASH
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection