34 research outputs found

    Roles of peptide–peptide charge interaction and lipid phase separation in helix–helix association in lipid bilayer

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    AbstractThe roles of peptide–peptide charged interaction and lipid phase separation in helix–helix association in lipid bilayers were investigated using a model peptide, P24, as a transmembrane α-helical peptide, and its four analogues. Fluorescence amino acids, tryptophan (P24W) and pyrenylalanine (P24Pya), were introduced into the sequence of P24, respectively. Association of these peptides permits the resonance excitation energy transfer between tryptophan in P24W and pyrenylalanine in P24Pya or excimer formation between P24Pya themselves. To evaluate the effect of charged interaction on the association between α-helical transmembrane segments in membrane proteins, charged amino acids, glutamic acid (P24EW) and lysine (P24KPya), were introduced into P24W and P24Pya, respectively. Energy transfer experiments indicated that the charged interaction between the positive charge of lysine residue in P24KPya and the negative charge of glutamic acid residue in P24EW did not affect the aggregation of transmembrane peptides in lipid membranes. As the content ratio of sphingomyelin (SM) and cholesterol (Ch) was increased in the egg phosphatidylcholine (PC), the stronger excimer fluorescence spectra of P24Pya were observed, indicating that the co-existence of SM and Ch in PC liposomes, that is, the raft of SM and Ch, promotes the aggregation of the α-helical transmembrane peptides in lipid bilayers. Since the increase in the contents of SM and Ch leads to the decrease in the content of liquid crystalline-order phase, the moving area of transmembrane peptides might be limited in the liposomes, resulting in easy formation of the excimer in the presence of the lipid-raft

    The Japanese Clinical Practice Guideline for acute kidney injury 2016

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    Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search

    3. Renal Replacement Therapy for Acute Kidney Injury

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    腰椎すべり症における動態X線画像を用いた不安定性評価に対する姿勢の影響

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    Study design: Prospective clinical study. Purpose: To determine the optimal posture for instability evaluation using flexion-extension X-ray imaging in patients with lumbar spondylolisthesis. Overview of literature: Currently, flexion-extension X-ray imaging is the most practical approach for the evaluation of lumbar instability. In flexion-extension X-ray imaging, achievement of the greatest segmental motion with flexion-extension movement is necessary. However, to our knowledge, currently, there is no standardized posture for determining lumbar instability. Methods: Twenty-three individuals with lumbar spondylosis related to the fourth vertebra underwent flexion-extension X-ray imaging in different postures (standing, sitting, and lateral decubitus positions), lumbar magnetic resonance imaging (MRI), and low back pain Visual Analog Scale (VAS) evaluation on the same day. Intervertebral angle, percent slippage, and intervertebral disc area ratio for different postures during flexion and extension were compared using Tukey's method. The effect of low back pain and the association between MRI facet effusion and these measurements were investigated according to posture. Results: The percent slippage during extension (p=0.036), change in the percent slippage between flexion and extension (p=0.004), and change in the intervertebral angle (p=0.042) were significantly different between the sitting and lateral decubitus positions. There were also significant differences between the standing and lateral decubitus positions in the change in intervertebral angle (p=0.010). In patients with VAS score <40, there were significant differences in the intervertebral angle (p=0.011) between the standing and lateral decubitus positions, percent slippage (p=0.048), and intervertebral disk ratio (p=0.008) between the sitting and lateral decubitus positions. We found no relationship between MRI facet effusion and posture in terms of instability. Conclusions: In this study, intervertebral instability was best evaluated in the lateral decubitus position when using flexion-extension X-ray imaging for patients with fourth lumbar vertebral spondylolisthesis.博士(医学)・甲第754号・令和2年9月30日Copyright © 2020 by Korean Society of Spine SurgeryThis is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited

    Accuracy of Lateral Mass Screw Insertion during Cervical Spine Surgery without Fluoroscopic Guidance and Comparison of Postoperative Screw Loosening Rate among Unicortical and Bicortical Screws Using Computed Tomography

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    Introduction: Pedicle screws (PSs) or lateral mass screws (LMSs) are used in posterior cervical spine fixation. The former are more firmly fixed but are associated with the risk of neurovascular injury and should be inserted using intraoperative imaging or navigation, which may prolong the surgical duration and is not feasible in all hospitals. This prospective clinical study aimed to evaluate the outcomes of LMS insertions without fluoroscopic guidance and screw loosening rates at 6 months postoperatively using computed tomography (CT). Methods: We examined 38 patients who underwent posterior cervical spine fusion using 206 LMSs in the C3-C6 range between January 2018 and July 2021. The direction of screw insertion followed the Magerl method, and we inserted screws as bicortically as possible without intraoperative imaging. The screw position was examined using CT at 1 week postoperatively. Screw insertion angles, bicortical insertion rate, facet violation, and neurovascular injury were evaluated. Screw loosening with unicortical and bicortical screws (US and BS, respectively) was investigated using CT at 6 months postoperatively. Results: The average LMS length was 14.1 mm. The average axial and sagittal angles were 33.9° and 29.2°, respectively. Among the 206 LMSs inserted, 167 were BS; of these, 94.6% had screw length protrusion of 0-2 mm. Facet violation was observed in 3.4% of all screws but without neurovascular injury. Six months postoperatively, loosening of 25 screws (12.1%) occurred, including 17 (18.3%) USs and 8 (8.39%) BSs. The screw loosening rate was significantly higher in US than for BS (43.6% [17/39] vs. 4.8% [8/167], P<0.01). Conclusions: Over 80% of LMSs were inserted bicortically without intraoperative imaging. By devising the screw length selection process, we inserted for screw loosening was more common in US and more likely at the fixed end
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