Histone variant H2A.B-H2B dimers are spontaneously exchanged with canonical H2A-H2B in the nucleosome

精子形成に重要なヒストンによるDNAの新たな折りたたみを解明. 京都大学プレスリリース. 2021-02-22.H2A.B is an evolutionarily distant histone H2A variant that accumulates on DNA repair sites, DNA replication sites, and actively transcribing regions in genomes. In cells, H2A.B exchanges rapidly in chromatin, but the mechanism has remained enigmatic. In the present study, we found that the H2A.B-H2B dimer incorporated within the nucleosome exchanges with the canonical H2A-H2B dimer without assistance from additional factors, such as histone chaperones and nucleosome remodelers. High-speed atomic force microscopy revealed that the H2A.B nucleosome, but not the canonical H2A nucleosome, transiently forms an intermediate “open conformation”, in which two H2A.B-H2B dimers may be detached from the H3-H4 tetramer and bind to the DNA regions near the entry/exit sites. Mutational analyses revealed that the H2A.B C-terminal region is responsible for the adoption of the open conformation and the H2A.B-H2B exchange in the nucleosome. These findings provide mechanistic insights into the histone exchange of the H2A.B nucleosome

Postoperative Swallowing Function in Patients with Deep Neck Infection

Introduction: Early detection of dysphagia risk, initiating rehabilitation, and resumption of appropriate diet based on swallowing function is important during deep neck infection (DNI) control. This study aimed to evaluate the extent of cervical abscess development, particularly in the deep neck space, and its relationship to postoperative swallowing function. Methods: A retrospective chart review was performed for all DNI cases treated between April 2015 and April 2021. Deep neck spaces were divided into categories based on computed tomography findings. Functional Oral Intake Scale (FOIS) scores of 4 or higher was defined as normal or slight swallowing disorder and 3 or lower as dysphagia. Results: Seventeen cases were included in the analysis. Based on FOIS, 14 cases were classified into the dysphagia group at 2 weeks after surgery, 11 cases at 4 weeks, and 8 cases at 8 weeks. There was no significant difference between the location of the abscess and dysphagia at 2 weeks after surgery. Patients with anterior cervical space abscess significantly increased dysphagia 4 weeks (p = 0.018) and 8 weeks (p = 0.036) after surgery. Conclusion: Abscess formation in the anterior cervical space may be associated with prolonged dysphagia after treatment due to inflammation and scarring of the muscles associated with swallowing

Integral approach to biomacromolecular structure by analytical-ultracentrifugation and small-angle scattering

溶液中の蛋白質構造を正確に評価するための新規解析法を開発 --構造評価の妨げとなる凝集の影響を実験データから除去--. 京都大学プレスリリース. 2020-06-09.Currently, a sample for small-angle scattering (SAS) is usually highly purified and looks monodispersed: The Guinier plot of its SAS intensity shows a fine straight line. However, it could include the slight aggregates which make the experimental SAS profile different from the monodispersed one. A concerted method with analytical-ultracentrifugation (AUC) and SAS, named as AUC-SAS, offers the precise scattering intensity of a concerned biomacromolecule in solution even with aggregates as well that of a complex under an association-dissociation equilibrium. AUC-SAS overcomes an aggregation problem which has been an obstacle for SAS analysis and, furthermore, has a potential to lead to a structural analysis for a general multi-component system

Quasispecies variant of pre-S/S gene in HBV-related hepatocellular carcinoma with HBs antigen positive and occult infection

Abstract Background Hepatocellular carcinoma (HCC) can develop in patients who are negative for the hepatitis B surface antigen (HBsAg) in serum but positive for hepatitis B virus (HBV) DNA in the liver, referred to as occult HBV infection (OBI). Previous reports showed that HBV variants in OBI-related HCC are different from those in HBsAg-positive HCC. In the present study, HBV quasispecies based on the pre-S/S gene in OBI-related HCC patients were examined by high throughput sequencing and compared with those in HBsAg-positive HCC. Methods Nineteen tissue samples (9 OBI-related and 10 HBsAg-positive non-cancerous tissues) were collected at the time of surgery at Kobe University Hospital. The quasispecies with more than 1% variation in the pre-S/S region were isolated and analysed by ultra-deep sequencing. Results There were no significant differences in the major HBV populations, which exhibit more than 20% variation within the entire pre-S/S region, between OBI-related HCC and HBsAg-positive HCC. However, the prevalences of major populations with pre-S2 region mutations and of minor populations with polymerized human serum albumin-binding domain mutations were significantly higher in OBI-related HCC than in HBsAg-positive HCC. Moreover, the major variant populations associated with the B-cell epitope, located within the pre-S1 region, and the a determinant domain, located in the S region, were detected frequently in HBsAg-positive HCC. The minor populations of variants harbouring the W4R, L30S, Q118R/Stop, N123D and S124F/P mutations in the pre-S region and the L21F/S and L42F/S mutations in the S region were detected more frequently in OBI-related HCC than in HBsAg-positive HCC. Conclusions Ultra-deep sequencing revealed that the B-cell epitope domain in the pre-S1 region and alpha determinant domain in the S region were variable in HBsAg-positive HCC, although the quasispecies associated with the pre-S2 region were highly prevalent in OBI-related HCC. Trial registration Ref: R000034382/UMIN000030113; Retrospectively registered 25 November 2017

Effect of Ezetimibe on LDL-C Lowering and Atherogenic Lipoprotein Profiles in Type 2 Diabetic Patients Poorly Controlled by Statins

<div><p>Background</p><p>There exists a subpopulation of T2DM in whom first-line doses of statin are insufficient for optimally reducing LDL-C, representing a major risk of CVD. The RESEARCH study focuses on LDL-C reduction in this population along with modifications of the lipid profiles leading to residual risks.</p><p>Methods</p><p>Lipid changes were assessed in a randomized, multicenter, 12-week, open-label study comparing a high-potency statin (10mg of atorvastatin or 1mg of pitavastatin) plus ezetimibe (EAT: n = 53) with a double dose of statin (20mg of atorvastatin or 2mg of pitavastatin) (DST: n = 56) in DM subjects who had failed to achieve the optimal LDL-C targets. Lipid variables were compared with a primary focus on LDL-C and with secondary focuses on the percentage of patients who reached the LDL-C targets and changes in the levels of RLP-C (remnant like particle cholesterol) and sd-LDL-C, two characteristic atherogenic risks of DM.</p><p>Results</p><p>The reduction of LDL-C (%), the primary endpoint, differed significantly between the two groups (-24.6 in EAT vs. -10.9 in DST). In the analyses of the secondary endpoints, EAT treatment brought about significantly larger reductions in sd-LDL-C (-20.5 vs. -3.7) and RLP-C (-19.7 vs. +5.5). In total, 89.4% of the patients receiving EAT reached the optimized treatment goal compared to 51.0% of the patients receiving DST. The changes in TC (-16.3 vs. -6.3) and non-HDL-C (-20.7 vs. -8.3) differed significantly between the two groups.</p><p>Conclusion</p><p>Ezetimibe added to high-potency statin (10 mg of atorvastatin or 1 mg of pitavastatin) was more effective than the intensified-dose statin (20 mg of atorvastatin or 2 mg of pitavastatin) treatment not only in helping T2DM patients attain more LDL-C reduction, but also in improving their atherogenic lipid profiles, including their levels of sd-LDL-C and RLP-C.</p><p>We thus recommend the addition of ezetimibe to high-potency statin as a first line strategy for T2DM patients with insufficient statin response.</p><p>Trial Registration</p><p>The UMIN Clinical Trials Registry <a href="https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000003155&language=E/UMIN000002593" target="_blank">UMIN000002593</a></p></div