45 research outputs found

    Fermi surface reconstruction due to the orthorhombic distortion in Dirac semimetal YbMnSb2_2

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    Dirac semi-metal with magnetic atoms as constituents delivers an interesting platform to investigate the interplay of Fermi surface (FS) topology, electron correlation, and magnetism. One such family of semi-metal is YbMnPn2Pn_2 (PnPn = Sb, Bi), which is being actively studied due to the intertwined spin and charge degrees of freedom. In this Letter, we investigate the relationship between the magnetic/crystal structures and FS topology of YbMnSb2_2 using single crystal x-ray diffraction, neutron scattering, magnetic susceptibility, magnetotransport measurement and complimentary DFT calculation. Contrary to previous reports, the x-ray and neutron diffraction reveal that YbMnSb2_2 crystallizes in an orthorhombic PnmaPnma structure with notable anti-phase displacement of the magnetic Mn ions that increases in magnitude upon cooling. First principles DFT calculation reveals a reduced Brillouin zone and more anisotropic FS of YbMnSb2_2 compared to YbMnBi2_2 as a result of the orthorhombicity. Moreover, the hole type carrier density drops by two orders of magnitude as YbMnSb2_2 orders antiferromagnetically indicating band folding in magnetic ordered state. In addition, the Landau level fan diagram yields a non-trivial nature of the SdH quantum oscillation frequency arising from the Dirac-like Fermi pocket. These results imply that YbMnSb2_2 is an ideal platform to explore the interplay of subtle lattice distortion, magnetic order, and topological transport arising from relativistic quasiparticles.Comment: 11 pages, contains 4 figures and 7 Supplemental Figure

    Hybrid Brachytherapy of Cervical Cancer

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    High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in cervical cancer disclosed that the traditional intracavitary brachytherapy by Manchester method cannot deliver an adequate dose to the large tumor with resulting local recurrence. To improve the local control rate, combined interstitial and intracavitary (hybrid) brachytherapy can increase the dose to the large parametrial involvement without increasing the dose to the rectum and bladder. Whether hybrid brachytherapy can be performed safely on a multi-institutional basis remains to be studied. From 2015, phase I/II study of hybrid brachytherapy was launched in Japan, and it was revealed that hybrid brachytherapy can be performed safely and with a high quality of radiation dose distribution in a multi-institutional study. In Japan, the number of patients undergoing hybrid brachytherapy in cervical cancer is rapidly rising. Education and clinical trial are very important to establish hybrid brachytherapy in the management of cervical cancer

    Two cases of Taeniasis Infection.

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    We report two cases of taeniasis caused by tapeworm infection. The first was a Japanese female, 23 years old, who had a history of eating raw meat during a visit to Thailand. She was referred to our hospital with a history of passing proglottids in feces. Taenia saginata or T. asiatica was suspected based on the proglottid morphologic features in addition to supportive information regarding her travel and dietary history. The patient was given praziquantel and the tapeworm was excreted. The second was a 35-year-old Thai male who had lived in Japan since 2000 and not left the country since that time. He had consumed beef cooked in the so-called yakiniku style and also sometimes raw, because of nostalgia for that Thai custom. The patient passed proglottids several times and then came to us. The proglottids were compatible with those of T. saginata. Praziquantel was prescribed and the tapeworm was excreted. In both cases, mitochondrial DNA analysis identified the worm species as T. saginata. Since morphological discrimination of three human-infecting Taenia species, T. saginata, T. solium, and T. asiatica, is not always possible, it is necessary to employ DNA analysis for diagnosis of taeniasis to confirm the worm species

    The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

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    「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

    DOCK2 is involved in the host genetics and biology of severe COVID-19

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    「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

    Fine needle aspiration cytology of adenocarcinoma of the rectovaginal septum: a case report

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    Adenocarcinoma arising in the rectovaginal septum is exceedingly rare and is difficult to diagnose by pathologic examination prior to surgery because of the anatomic position of the tumor. CASE: A 42-year-old woman presumed to have adenocarcinoma of the rectovaginal septum underwent fine needle aspiration for diagnosis. Although a previously performed biopsy from the posterior vaginal fornix was unsuccessful, fine needle aspiration cytology via the posterior vaginal wall detected adenocarcinoma cells. The cell clusters were composed of cells with enlarged and hyperchromatic nuclei. The nuclei themselves demonstrated round and/or irregular morphologic patterns, with high nuclear/cytoplasmic ratios, and often contained an enlarged, round nucleolus and sometimes multiple ones in a single nucleus. Anisonucleosis was severe, and the chromatin patterns ranged from coarse to finely granular. The cytoplasm was narrow and lightly stained. Following fine needle aspiration, the patient underwent posterior exenteration on the basis of the cytologic diagnosis. CONCLUSION: Fine needle aspiration cytology was useful in establishing the preoperative diagnosis of adenocarcinoma of the rectovaginal septum, and curative exenterative surgery could be then performed. To our knowledge, this is the first report of fine needle aspiration cytology of adenocarcinoma at this location
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