Publications by authors named "Kentaro Abe"

32 Publications

Bilirubin is inversely related to diabetic peripheral neuropathy assessed by sural nerve conduction study.

J Diabetes Investig 2021 May 5. Epub 2021 May 5.

Fukuoka City Health Promotion Support Center, Fukuoka, Japan.

Aims/introduction: Diagnosis of diabetic peripheral neuropathy (DPN) depends on subjective findings, certain investigations for DPN risks have not been performed enough. Bilirubin protects against vascular complications by reducing oxidative stress in diabetes, but is not fully tested for DPN. This study aimed to evaluate sural nerve conduction impairments (SNCI) as an objective DPN marker and the contribution of bilirubin to SNCI.

Materials And Methods: Using DPN-Check , SNCI was defined as a decline of amplitude potential or conduction velocity below the normal limit in 150 inpatients with diabetes. The correlations between SNCI and conventional DPN diagnosis criteria, the incidence of diabetic retinopathy/nephropathy, biomarkers for atherosclerosis, cardiac function by ultrasonic cardiogram, and bilirubin were statistically tested, followed by the comparison of logistic regression models for SNCI to find confounders with bilirubin.

Results: The incidence of SNCI was 72.0%. The sensitivity and specificity of SNCI for DPN prediagnosis by simplified criteria were 54.6 and 90.5%, respectively, and similarly corresponded with diabetic retinopathy and nephropathy (sensitivity 57.4 and 50.0%, respectively). SNCI significantly related to diabetes duration, declined estimated glomerular filtration rate, albuminuria and total bilirubin. SNCI incidence was attenuated in the higher bilirubin tertiles (89.8/65.3/54.8%, P < 0.001). Bilirubin was an independent inverse risk factor for SNCI, even after adjustment by known risk factors for DPN and markers for microvascular complications.

Conclusions: SNCI is a comprehensive marker for diabetic complications. We first showed the independent inverse relationship between bilirubin and SNCI through the independent pathway with other complications, provably reducing oxidative stress, as previously reported.
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http://dx.doi.org/10.1111/jdi.13568DOI Listing
May 2021

Performance evaluation of case definitions of type 1 diabetes for health insurance claims data in Japan.

BMC Med Inform Decis Mak 2021 02 11;21(1):52. Epub 2021 Feb 11.

Medical Information Center, Kyushu University Hospital, Maidashi 3-1-1 Higashi-ku, Fukuoka City, Fukuoka Prefecture, 812-8582, Japan.

Background: No case definition of Type 1 diabetes (T1D) for the claims data has been proposed in Japan yet. This study aimed to evaluate the performance of candidate case definitions for T1D using Electronic health care records (EHR) and claims data in a University Hospital in Japan.

Methods: The EHR and claims data for all the visiting patients in a University Hospital were used. As the candidate case definitions for claims data, we constructed 11 definitions by combinations of International Statistical Classification of Diseases and Related Health Problems, Tenth Revision. (ICD 10) code of T1D, the claims code of insulin needles for T1D patients, basal insulin, and syringe pump for continuous subcutaneous insulin infusion (CSII). We constructed a predictive model for T1D patients using disease names, medical practices, and medications as explanatory variables. The predictive model was applied to patients of test group (validation data), and performances of candidate case definitions were evaluated.

Results: As a result of performance evaluation, the sensitivity of the confirmed disease name of T1D was 32.9 (95% CI: 28.4, 37.2), and positive predictive value (PPV) was 33.3 (95% CI: 38.0, 38.4). By using the case definition of both the confirmed diagnosis of T1D and either of the claims code of the two insulin treatment methods (i.e., syringe pump for CSII and insulin needles), PPV improved to 90.2 (95% CI: 85.2, 94.4).

Conclusions: We have established a case definition with high PPV, and the case definition can be used for precisely detecting T1D patients from claims data in Japan.
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http://dx.doi.org/10.1186/s12911-021-01422-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7879626PMC
February 2021

The potential role of Arhgef33 RhoGEF in foveal development in the zebra finch retina.

Sci Rep 2020 12 8;10(1):21450. Epub 2020 Dec 8.

Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.

The fovea is a pit formed in the center of the retina that enables high-acuity vision in certain vertebrate species. While formation of the fovea fascinates many researchers, the molecular mechanisms underlying foveal development are poorly understood. In the current study, we histologically investigated foveal development in zebra finch (Taeniopygia guttata) and found that foveal pit formation begins just before post-hatch day 14 (P14). We next performed RNA-seq analysis to compare gene expression profiles between the central (foveal and parafoveal) and peripheral retina in zebra finch at P14. We found that the Arhgef33 expression is enriched in the middle layer of the inner nuclear layer at the parafovea, suggesting that Arhgef33 is dominantly expressed in Müller glial cells in the developing parafovea. We then performed a pull-down assay using Rhotekin-RBD and observed GEF activity of Arhgef33 against RhoA. We found that overexpression of Arhgef33 in HEK293 cells induces cell contraction and that Arhgef33 expression inhibits neurite extension in Neuro 2A cells, which is partially recovered by a Rho-kinase (ROCK) inhibitor. Taken together, we used zebra finch as a model animal to investigate foveal development and identified Arhgef33 as a candidate protein possibly involved in foveal development through modulating RhoA activity.
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http://dx.doi.org/10.1038/s41598-020-78452-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722920PMC
December 2020

Panophthalmitis after Pecking by a Great Egret ().

Case Rep Ophthalmol 2020 May-Aug;11(2):466-472. Epub 2020 Aug 11.

Department of Ophthalmology, Miyata Eye Hospital, Miyazaki, Japan.

We report a case of open globe injury caused by pecking that resulted in panophthalmitis. A woman in her 70s complaining of ocular pain was referred to our hospital because her right eye had been pecked by an 2 days earlier. Visual acuity in her right eye was reduced to light sensation. The right conjunctiva became hyperemic and edematous with swelling of the right upper eyelid. The upper side of the right cornea was densely cloudy with focal defect. Ultrasonography showed a thick sclera and choroid-like structure. Pathological investigation of a scraped sample from the infected site revealed gram-negative rods; was isolated. She had fever with elevated serum C-reactive protein levels and leukocytosis confirmed by laboratory examination. Topical levofloxacin and cefmenoxime and intravenous fosfomycin and aspoxicillin were initiated, but the right cornea melted near the perforated site with leakage of the eyeball contents on the next day. We decided to perform eye evisceration because of difficulty in controlling corneal melting and panophthalmitis. Her general state recovered the day after surgery. Orbital cellulitis improved gradually with normal C-reactive protein levels and white blood cell counts. As ocular injury caused by birds could become severe and cause ocular infection and visual dysfunction, it is important to exercise caution in the vicinity of wild birds, especially when they are aggressive.
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http://dx.doi.org/10.1159/000509340DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7506268PMC
August 2020

Long-term changes and effect of pterygium size on corneal topographic irregularity after recurrent pterygium surgery.

Sci Rep 2020 05 21;10(1):8398. Epub 2020 May 21.

Miyata Eye Hospital, Miyazaki, Japan.

This retrospective observational study compared long-term topographic changes after recurrent- and primary-pterygium surgery depending on pterygium size. Patients who underwent recurrent-pterygium excision between 2002-2013 and age, sex, and pterygium size-matched controls who underwent primary-pterygium surgery were included (33 eyes of 33 patients in each group). Pterygium size was graded per advancing edge position: <1/3 of corneal diameter (grade 1), outside the pupil (grade 2), and within the pupillary area (grade 3). Surface asymmetry index (SAI), surface regularity index (SRI) in corneal topography, and uncorrected and best-spectacle-corrected visual acuity were compared before and 1, 3, 6, and 12 months postoperatively. Three, 17, and 13 eyes had grades 1, 2, and 3, respectively. In grade 2, the SAI and SRI were respectively significantly larger at all observation points (p = 0.01, 0.03, 0.02, 0.02, and 0.004) and before and 6 and 12 months postoperatively (p = 0.02, 0.04, and 0.03) in recurrent pterygium. In grade 3, the SAI was significantly larger before and 1, 3, and 12 months postoperatively (p = 0.04, 0.01, 0.01, and 0.02) and the SRI was significantly larger before and 12 months postoperatively (p < 0.001, 0.02) in recurrent pterygium. Corneal irregularity persisted 12 months after recurrent-pterygium surgery compared with that in same-size primary pterygium.
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http://dx.doi.org/10.1038/s41598-020-65376-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7242432PMC
May 2020

Serum KL-6 elevation in a uveitis patient with Behçet's disease treated with adalimumab.

Am J Ophthalmol Case Rep 2020 Jun 13;18:100660. Epub 2020 Mar 13.

Miyata Eye Hospital, Miyazaki, Japan.

Purpose: To report a case of uveitis with Behçet's disease in which serum levels of Krebs von den Lungen (KL)-6, a marker of interstitial lung disease, were elevated during treatment with adalimumab and returned to baseline after discontinuation of the agent.

Observations: A 67-year-old man complaining of vision disturbance was referred to our hospital. The patient had a history of recurrent episodes of bilateral uveitis and oral ulcers, and had been diagnosed with Behçet's disease. While uveitis activity was not well controlled under administration of oral prednisolone and cyclosporin, cataract of the right eye developed and required surgery. Biweekly administration of adalimumab 40 mg was therefore initiated with prednisolone at 15 mg/day. Uveitis became well controlled and cataract surgery was successfully carried out for the right eye. However, serum KL-6 gradually elevated to 1002 U/ml by 6 months after adalimumab initiation and 1277 U/ml at 9 months. Because serum KL-6 >1000 U/ml has been reported to predict interstitial lung disease, we discontinued adalimumab and started cyclosporine at 100 mg/day. Serum KL-6 gradually decreased and returned to baseline levels, no interstitial lung disease developed and exacerbation of uveitis was avoided.

Conclusions And Importance: This case implies the clinical importance of monitoring serum KL-6 in patents with non-infectious uveitis being treated with adalimumab.
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http://dx.doi.org/10.1016/j.ajoc.2020.100660DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083778PMC
June 2020

Insect Cuticle-Mimetic Hydrogels with High Mechanical Properties Achieved via the Combination of Chitin Nanofiber and Gelatin.

J Agric Food Chem 2019 May 2;67(19):5571-5578. Epub 2019 May 2.

Research Institute for Sustainable Humanosphere , Kyoto University , Uji , Kyoto 611-0011 , Japan.

By mimicking the natural sclerotization process of insect cuticles, a novel nanofiber-reinforced gelatin hydrogel was developed with improved mechanical properties, which was further strengthened through quinone cross-linking. Because quinone cross-linking reacts between amino groups by increasing the amino group content on the chitin crystalline surface through alkali treatment, surface-deacetylated chitin nanofibers (SD-ChNFs) were prepared to facilitate the cross-linking reaction between SD-ChNF and gelatin. This technique resulted in a tough hydrogel with a dark color. In comparison to a non-cross-linked version, the quinone-cross-linked SD-ChNF/gelatin hydrogel exhibited significantly improved tensile performance. Notably, by controlling the cross-linking reaction time from 6 to 48 h, the tensile strength of the quinone-cross-linked hydrogels can be modified and can reach as high as 2.96 MPa while displaying a variable brown color. Given the eco-friendly, biocompatible, and sustainable properties of chitin and gelatin, these bioinspired hydrogels provide potential applications in the agricultural and biomedical fields.
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http://dx.doi.org/10.1021/acs.jafc.9b00984DOI Listing
May 2019

Bioinspired hydrogels: Quinone crosslinking reaction for chitin nanofibers with enhanced mechanical strength via surface deacetylation.

Carbohydr Polym 2019 Mar 5;207:411-417. Epub 2018 Dec 5.

Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan.

Suffering weak mechanical properties, hydrogels are generally limited to be applied as load-bearing materials. Previously, we introduced methods to fabricate high-strength hydrogels using chitin nanofibers (ChNFs) under alkali or calcium chloride conditions. This work provides an alternative approach for the preparation of quinone-crosslinked ChNF-based hydrogels using amino groups, which inspired by the quinone hardening process during insect cuticle sclerotization. By increasing the number of amino groups on the chitin crystalline surface through deacetylation, the resulting surface-deacetylated chitin nanofiber (S-ChNF) transformed to a dark hydrogel when reacted in hydroquinone (HQ)/copper (Cu(II)) solutions. The results show that the S-ChNF-based hydrogel displayed almost 10-fold higher tensile strength than the ChNF-based hydrogel due to the extended crosslinking effect between quinone and amino groups. Given the natural sustainability of chitin and the demonstrated improved mechanical strength, this work offers a promising strategy to fabricate a bioinspired S-ChNF-based hydrogel for potential applications in bio-medical engineering fields.
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http://dx.doi.org/10.1016/j.carbpol.2018.12.007DOI Listing
March 2019

Novel fabrication of high-modulus cellulose-based films by nanofibrillation under alkaline conditions.

Authors:
Kentaro Abe

Carbohydr Polym 2019 Feb 30;205:488-491. Epub 2018 Oct 30.

Research Institute for Sustainable Humanosphere, Kyoto University, Japan. Electronic address:

We herein propose a novel continuous process for fabricating high-modulus films based on cellulose nanofibers. In place of a dissolution process, the pulps were mechanically disintegrated into nanofibers by ball-milling in an 8% NaOH solution. NaOH treatment loosened the hydrogen bonding between the cellulose microfibrils in the pulps, and a highly concentrated suspension (8%) of cellulose nanofibers with a uniform diameter of approximately 20-50 nm was prepared after ball-milling for 90 min. The resulting nanofiber suspensions prepared in the NaOH solution exhibited the crystal forms of both Cellulose I and Cellulose II, although the Cellulose II content gradually increased upon increasing the milling time. Finally, hydrogels were formed following neutralization of the suspensions, and the hydrogel sheets were hot-pressed into thin films at 120 °C. The Young's moduli of the films were significantly higher than those of typical regenerated cellulose films due to the presence of some remaining Cellulose I and a high crystallinity.
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http://dx.doi.org/10.1016/j.carbpol.2018.10.069DOI Listing
February 2019

Carrier Transport Mechanism in Single Crystalline Organic Semiconductor Thin Film Elucidated by Visualized Carrier Motion.

J Nanosci Nanotechnol 2016 Apr;16(4):3388-93

Time-resolved microscopic second harmonic generation (TRM-SHG) measurement was conducted to evaluate temperature dependence of the anisotropic carrier transport process in 6,13-Bis(triisopropylsilylethynyl) (TIPS) pentacene single crystalline domains for two orthogonal directions. Enhancement of the electric field induced SHG (EFI-SHG) signal at the electrode edge at low temperature suggests the presence of potential drop in the injection process. We directly evaluated temperature dependence of the carrier mobility by taking into account the potential drop, and concluded that the Marcus theory is appropriate to interpret the carrier transport in anisotropic TIPS pentacene thin film. TRM-SHG method is a facile and effective way to directly visualize transport process in anisotropic materials and to evaluate injection and transport processes simultaneously.
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http://dx.doi.org/10.1166/jnn.2016.12321DOI Listing
April 2016

Silent myocardial ischemia in asymptomatic patients with type 2 diabetes mellitus without previous histories of cardiovascular disease.

Int J Cardiol 2016 Aug 11;216:151-5. Epub 2016 Apr 11.

Cardiovascular Center, Munakata Suikokai General Hospital, Fukutsu, Japan.

Background: The number of patients with type 2 diabetes mellitus (T2DM) continues to increase all over the world. Cardiovascular disease (CVD), especially coronary artery disease (CAD), is a major cause of the morbidity and mortality in patients with T2DM. The prognosis of patients with silent myocardial ischemia (SMI) is worse than that in those without.

Methods And Results: Thus, to assess how many patients with SMI existed among those patients, CVD screening tests were performed in 128 asymptomatic patients with T2DM without previous histories of CVD. SMI could be detected in 24 patients (19%) by exercise stress tests and/or the coronary fractional flow reserve. Their 12-lead electrocardiogram and cardiac ultrasonography were both normal. Compared to those without SMI, those with had a statistically significant longer history of T2DM (17±1 versus 11±1years, p=0.006), and the co-existence of a family history of CVD (42% versus 21%, p=0.037). Furthermore, these factors were demonstrated as independent risk factors of SMI by a multivariate analysis (Odds ratio 1.060 and 4.000, respectively), and in accordance with the disease duration of T2DM, the prevalence of patients with SMI has been increasing (p=0.019).

Conclusions: Physicians should be aware of these conditions when examining patients with T2DM, especially with a family history of CVD and/or long disease duration (>11years) of T2DM, even though they have no symptoms, previous histories of CVDs, and/or abnormal findings on the 12-lead electrocardiogram and cardiac ultrasonography. This may be an effective, safe, and attractive diagnostic strategy for those asymptomatic patients with T2DM.
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http://dx.doi.org/10.1016/j.ijcard.2016.04.008DOI Listing
August 2016

Time-dependent localization of high- and low-sulfated keratan sulfates in the song nuclei of developing zebra finches.

Eur J Neurosci 2015 Nov 26;42(9):2716-25. Epub 2015 Oct 26.

Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.

Keratan sulfate proteoglycans (KSPGs) and chondroitin sulfate proteoglycans (CSPGs) consist of a protein core with covalently attached glycosaminoglycan side chain. Although CSPGs are known to regulate the end of the critical period, the role of KSPGs in brain development remains unclear. Young male zebra finches memorise song templates during development. The brain regions that are responsible for song learning, known as song nuclei, are recognized as a suitable model for the study of brain development. To understand the potential role of KSPGs, here we examined the localization of KSs with different degrees of sulfation in the brain of developing male zebra finches. Exclusively in the song nuclei, an increase in expression of 5-D-4-positive (5-D-4(+)) high-sulfated KS started after hatching, and reached a plateau at the end of the sensory period, during which the young bird listens to and memorises the song of an adult tutor. By contrast, weak and ubiquitous expression of BCD-4(+) low-sulfated KS remained unchanged until the end of the sensory period, and first increased in the song nuclei at the end of the sensorimotor period, during which the young bird produces plastic songs. Immunoblot analysis showed that phosphacan was a common core protein of 5-D-4(+) KS and BCD-4(+) KS. Finally, we confirmed that the sulfotransferase responsible for the synthesis of high-sulfated KS was exclusively localised in the song nuclei. Our observations suggest that time-dependent localization of KSPGs with different sulfation patterns in the song nuclei may underlie song learning in developing male zebra finches.
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http://dx.doi.org/10.1111/ejn.13073DOI Listing
November 2015

Perospirone Exhibits Antiemetic Efficacy against Opioid-Induced Nausea in Patients with Advanced Cancer.

J Palliat Med 2015 Oct 24;18(10):823-4. Epub 2015 Aug 24.

1 Department of Palliative Medicine, National Cancer Center Hospital , Tokyo, Japan .

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http://dx.doi.org/10.1089/jpm.2015.0219DOI Listing
October 2015

Transgenic songbirds with suppressed or enhanced activity of CREB transcription factor.

Proc Natl Acad Sci U S A 2015 Jun 5;112(24):7599-604. Epub 2015 Jun 5.

Department of Biological Sciences, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan;

Songbirds postnatally develop their skill to utter and to perceive a vocal signal for communication. How genetic and environmental influences act in concert to regulate the development of such skill is not fully understood. Here, we report the phenotype of transgenic songbirds with altered intrinsic activity of cAMP response element-binding protein (CREB) transcription factor. By viral vector-mediated modification of genomic DNA, we established germ line-transmitted lines of zebra finches, which exhibited enhanced or suppressed activity of CREB. Although intrinsically acquired vocalizations or their hearing ability were not affected, the transgenic birds showed reduced vocal learning quality of their own songs and impaired audio-memory formation against conspecific songs. These results thus demonstrate that appropriate activity of CREB is necessary for the postnatal acquisition of learned behavior in songbirds, and the CREB transgenic birds offer a unique opportunity to separately manipulate both genetic and environmental factors that impinge on the postnatal song learning.
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http://dx.doi.org/10.1073/pnas.1413484112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4475973PMC
June 2015

Polymethylsilsesquioxane-cellulose nanofiber biocomposite aerogels with high thermal insulation, bendability, and superhydrophobicity.

ACS Appl Mater Interfaces 2014 Jun 6;6(12):9466-71. Epub 2014 Jun 6.

Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.

Polymethylsilsesquioxane-cellulose nanofiber (PMSQ-CNF) composite aerogels have been prepared through sol-gel in a solvent containing a small amount of CNFs as suspension. Since these composite aerogels do not show excessive aggregation of PMSQ and CNF, the original PMSQ networks are not disturbed. Composite aerogels with low density (0.020 g cm(-3) at lowest), low thermal conductivity (15 mW m(-1) K(-1)), visible light translucency, bending flexibility, and superhydrophobicity thus have been successfully obtained. In particular, the lowest density and bending flexibility have been achieved with the aid of the physical supporting effect of CNFs, and the lowest thermal conductivity is comparable with the original PMSQ aerogels and standard silica aerogels. The PMSQ-CNF composite aerogels would be a candidate to practical high-performance thermal insulating materials.
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http://dx.doi.org/10.1021/am501822yDOI Listing
June 2014

Preparation using pectinase and characterization of nanofibers from orange peel waste in juice factories.

J Food Sci 2014 Jun 7;79(6):N1218-24. Epub 2014 May 7.

Paper Industry Innovation Center, Ehime Univ, 127 Mendori-cho, Shikokuchuo, Ehime, 799-0113, Japan.

Unlabelled: This study reports the preparation and characterization of nanofibers consisting mainly of cellulose microfibrils from orange peel (OP), which is a significant byproduct of orange juice production. Three treatments (boiling, alkaline, and pectinase) were investigated with and without subsequent grinding treatment. It was possible to prepare the cellulose nanofibers (CNFs) using these methods, except for the boiling treatment with grinding. Interestingly, only pectinase and a mild-physical blender treatment without grinding produced nanofibers. The width of the nanofibers from OP was approximately 10 to 50 nm. The microfibril bundles of OP were considered to be thinner than those of commercial CNFs. Our data indicated that the removal of pectic polysaccharides and hemicelluloses covering the cellulose microfibrils was important for the preparation of nanofibers from OP. These nanofibers from OP using pectinase are proposed to be applicable as food materials, pharmaceuticals, and filters for the tractive characteristics of the sheet.

Practical Application: This study demonstrates: (1) it was possible to prepare the nanofibers from orange peel using pectinase and (2) the width of the nanofibers from orange peel was approximately 10 to 50 nm. (3) Removal of polysaccharides such as pectin and hemicelluloses covering cellulose microfibrils was very important for preparation of nanofibers from OP. Considering the tractive characteristics of the sheets from nanofibers and the origin of orange peel, they are suitable for application of food materials, pharmaceuticals, and filters.
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http://dx.doi.org/10.1111/1750-3841.12471DOI Listing
June 2014

An autoinhibited structure of α-catenin and its implications for vinculin recruitment to adherens junctions.

J Biol Chem 2013 May 15;288(22):15913-25. Epub 2013 Apr 15.

Campbell Family Cancer Research Institute, Ontario Cancer Institute, Toronto, Ontario M5G 1L7, Canada.

α-Catenin is an actin- and vinculin-binding protein that regulates cell-cell adhesion by interacting with cadherin adhesion receptors through β-catenin, but the mechanisms by which it anchors the cadherin-catenin complex to the actin cytoskeleton at adherens junctions remain unclear. Here we determined crystal structures of αE-catenin in the autoinhibited state and the actin-binding domain of αN-catenin. Together with the small-angle x-ray scattering analysis of full-length αN-catenin, we deduced an elongated multidomain assembly of monomeric α-catenin that structurally and functionally couples the vinculin- and actin-binding mechanisms. Cellular and biochemical studies of αE- and αN-catenins show that αE-catenin recruits vinculin to adherens junctions more effectively than αN-catenin, partly because of its higher affinity for actin filaments. We propose a molecular switch mechanism involving multistate conformational changes of α-catenin. This would be driven by actomyosin-generated tension to dynamically regulate the vinculin-assisted linkage between adherens junctions and the actin cytoskeleton.
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http://dx.doi.org/10.1074/jbc.M113.453928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668747PMC
May 2013

Songbirds possess the spontaneous ability to discriminate syntactic rules.

Nat Neurosci 2011 Jun 26;14(8):1067-74. Epub 2011 Jun 26.

Department of Molecular and Systems Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.

Whether the computational systems in language perception involve specific abilities in humans is debated. The vocalizations of songbirds share many features with human speech, but whether songbirds possess a similar computational ability to process auditory information as humans is unknown. We analyzed their spontaneous discrimination of auditory stimuli and found that the Bengalese finch (Lonchura striata var. domestica) can use the syntactical information processing of syllables to discriminate songs). These finches were also able to acquire artificial grammatical rules from synthesized syllable strings and to discriminate novel auditory information according to them. We found that a specific brain region was involved in such discrimination and that this ability was acquired postnatally through the encounter with various conspecific songs. Our results indicate that passerine songbirds spontaneously acquire the ability to process hierarchical structures, an ability that was previously supposed to be specific to humans.
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http://dx.doi.org/10.1038/nn.2869DOI Listing
June 2011

Genome comparison and context analysis reveals putative mobile forms of restriction-modification systems and related rearrangements.

Nucleic Acids Res 2010 Apr 12;38(7):2428-43. Epub 2010 Jan 12.

Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan.

The mobility of restriction-modification (RM) gene complexes and their association with genome rearrangements is a subject of active investigation. Here we conducted systematic genome comparisons and genome context analysis on fully sequenced prokaryotic genomes to detect RM-linked genome rearrangements. RM genes were frequently found to be linked to mobility-related genes such as integrase and transposase homologs. They were flanked by direct and inverted repeats at a significantly high frequency. Insertion by long target duplication was observed for I, II, III and IV restriction types. We found several RM genes flanked by long inverted repeats, some of which had apparently inserted into a genome with a short target duplication. In some cases, only a portion of an apparently complete RM system was flanked by inverted repeats. We also found a unit composed of RM genes and an integrase homolog that integrated into a tRNA gene. An allelic substitution of a Type III system with a linked Type I and IV system pair, and allelic diversity in the putative target recognition domain of Type IIG systems were observed. This study revealed the possible mobility of all types of RM systems, and the diversity in their mobility-related organization.
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http://dx.doi.org/10.1093/nar/gkp1226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2853133PMC
April 2010

Analysis of exposed cellulose surfaces in pretreated wood biomass using carbohydrate-binding module (CBM)-cyan fluorescent protein (CFP).

Biotechnol Bioeng 2010 Feb;105(3):499-508

Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Japan.

In enzymatic saccharification of lignocellulosics, the access of the enzymes to exposed cellulose surfaces is a key initial step in triggering hydrolysis. However, knowledge of the structure-hydrolyzability relationship of the pretreated biomass is still limited. Here we used fluorescent-labeled recombinant carbohydrate-binding modules (CBMs) from Clostridium josui as specific markers for crystalline cellulose (CjCBM3) and non-crystalline cellulose (CjCBM28) to analyze the complex surfaces of wood tissues pretreated with NaOH, NaOH-Na(2)S (kraft pulping), hydrothermolysis, ball-milling, and organosolvolysis. Japanese cedar wood, one of the most recalcitrant softwood species was selected for the analysis. The binding analysis clarified the linear dependency of the exposure of crystalline and non-crystalline cellulose surfaces for enzymatic saccharification yield by the organosolv and kraft delignification processes. Ball-milling for 5-30 min increased saccharification yield up to 77%, but adsorption by the CjCBM-cyan fluorescent proteins (CFPs) was below 5%. Adsorption of CjCBM-CFPs on the hydrothermolysis pulp were less than half of those for organosolvolysis pulp, in coincidence with low saccharification yields. For all the pretreated wood, crystallinity index was not directly correlated with the overall saccharification yield. Fluorescent microscopy revealed that CjCBM3-CFP and CjCBM28-CFP were site-specifically adsorbed on external fibrous structures and ruptured or distorted fiber surfaces. The assay system with CBM-CFPs is a powerful measure to estimate the initiation sites of hydrolysis and saccharification yields from chemically delignified wood pulps.
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http://dx.doi.org/10.1002/bit.22550DOI Listing
February 2010

Preparation of chitin nanofibers with a uniform width as alpha-chitin from crab shells.

Biomacromolecules 2009 Jun;10(6):1584-8

Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Minami, Tottori, Japan.

Chitin nanofibers were prepared from dried crab shells by a simple grinding treatment in a never-dried state under an acidic condition after the removal of proteins and minerals. The obtained nanofibers were observed by FE-SEM and found to have a uniform width of approximately 10-20 nm and high aspect ratio; both these findings were similar to those for nanofibers from prawns. Furthermore, it was confirmed that the nanofibers were extracted from the natural chitin/protein/mineral composites of crab shell in their original state. That is, the N-acetyl group was not removed and the alpha-chitin crystal structure was maintained, as confirmed by elemental analysis data, FT-IR spectra, and X-ray diffraction profiles.
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http://dx.doi.org/10.1021/bm900163dDOI Listing
June 2009

Neural activity-dependent regulation of gene expression in developing and mature neurons.

Authors:
Kentaro Abe

Dev Growth Differ 2008 May 10;50(4):261-71. Epub 2008 Mar 10.

RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.

Neurons can change their gene expression patterns according to the inputs they have received. This activity-dependent gene regulation mechanism plays an important role in the formation of neural circuits during development. Further, by regulating the synaptic plasticity, this mechanism may function as an essential one for each organism to adapt flexibly to its environment. This review summarizes our current knowledge about the activity-dependent gene regulation mechanism in neurons, focusing on the transcription factors and signaling pathways involved in this mechanism.
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http://dx.doi.org/10.1111/j.1440-169X.2008.00999.xDOI Listing
May 2008

The effect of hemicelluloses on wood pulp nanofibrillation and nanofiber network characteristics.

Biomacromolecules 2008 Mar 5;9(3):1022-6. Epub 2008 Feb 5.

Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.

Hemicelluloses as matrix substances showed an important role in nanofibrillation of wood pulp. Never-dried and once-dried pulps with different amounts of hemicelluloses were fibrillated using a grinding treatment. The degree of fibrillation was evaluated by scanning electron microscopy observation of the fibrillated pulps and light transmittance measurements of the fibrillated pulp/acrylic resin composites. With a one-pass grinding treatment, the once-dried pulp with higher hemicellulose content was fibrillated into 10-20 nm wide fibers as easily as the never-dried pulps, while the once-dried pulp with lower hemicellulose content was not fibrillated into uniform nanosized fibers. This result indicates that hemicelluloses act as inhibitors of the coalescence of microfibrils during drying and facilitate the nanofibrillation of once-dried pulp. Furthermore, hemicelluloses provide adhesion between nanofibers, contributing to reduction of thermal expansion and enhancement of mechanical properties in the composites.
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http://dx.doi.org/10.1021/bm701157nDOI Listing
March 2008

EPLIN mediates linkage of the cadherin catenin complex to F-actin and stabilizes the circumferential actin belt.

Proc Natl Acad Sci U S A 2008 Jan 18;105(1):13-9. Epub 2007 Dec 18.

RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.

The cadherin-catenin complex is the major machinery for cell-cell adhesion in many animal species. This complex in general associates with actin fibers at its cytoplasmic side, organizing the adherens junction (AJ). In epithelial cells, the AJ encircles the cells near their apical surface and forms the "zonula adherens" or "adhesion belt." The mechanism as to how the cadherin-catenin complex and F-actin cooperate to generate these junctional structures, however, remains unknown. Here, we show that EPLIN (epithelial protein lost in neoplasm; also known as Lima-1), an actin-binding protein, couples with alpha-catenin and, in turn, links the cadherin-catenin complex to F-actin. Without EPLIN, this linkage was unable to form. When EPLIN had been depleted in epithelial cells, the adhesion belt was disorganized and converted into zipper-like junctions in which actin fibers were radially arranged. However, nonjunctional actin fibers were not particularly affected by EPLIN depletion. As EPLIN is known to have the ability to suppress actin depolymerization, our results suggest that EPLIN functions to link the cadherin-catenin complex to F-actin and simultaneously stabilizes this population of actin fibers, resulting in the establishment of the adhesion belt.
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http://dx.doi.org/10.1073/pnas.0710504105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2224173PMC
January 2008

Obtaining cellulose nanofibers with a uniform width of 15 nm from wood.

Biomacromolecules 2007 Oct 5;8(10):3276-8. Epub 2007 Sep 5.

Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan.

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http://dx.doi.org/10.1021/bm700624pDOI Listing
October 2007

Excellent thermal conductivity of transparent cellulose nanofiber/epoxy resin nanocomposites.

Biomacromolecules 2007 Sep 14;8(9):2976-8. Epub 2007 Aug 14.

Materials Research Laboratory, HITACHI, Ltd., 7-1-1, Omika-cho, Hitachi 319-1292, Japan, Hitachi Chemical Company, Ltd., 48 Wadai, Tsukuba 300-4247, Japan. [email protected] hitachi.com

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http://dx.doi.org/10.1021/bm7004998DOI Listing
September 2007

Surface modification of bacterial cellulose nanofibers for property enhancement of optically transparent composites: dependence on acetyl-group DS.

Biomacromolecules 2007 Jun 26;8(6):1973-8. Epub 2007 Apr 26.

Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan.

Bacterial cellulose (BC) nanofibers were acetylated to enhance the properties of optically transparent composites of acrylic resin reinforced with the nanofibers. A series of BC nanofibers acetylated from degree-of-substitution (DS) 0 to 1.76 were obtained. X-ray diffraction profiles indicated that acetylation proceeded from the surface to the core of BC nanofibers, and scanning electron microscopy images showed that the volume of nanofibers increases by the bulky acetyl group. Since acetylation decreased the refractive index of cellulose, regular transmittance of composites comprised of 63% BC nanofiber was improved, and deterioration at 580 nm because of fiber reinforcement was suppressed to only 3.4%. Acetylation of nanofibers changed their surface properties and reduced the moisture content of the composite to about one-third that of untreated composite, although excessive acetylation increased hygroscopicity. Furthermore, acetylation was found to reduce the coefficient of thermal expansion of a BC sheet from 3 x 10(-6) to below 1 x 10(-6) 1/K.
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http://dx.doi.org/10.1021/bm070113bDOI Listing
June 2007

NMDA-receptor activation induces calpain-mediated beta-catenin cleavages for triggering gene expression.

Neuron 2007 Feb;53(3):387-97

Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.

The canonical Wnt-beta-catenin signaling pathway is important for a variety of developmental phenomena as well as for carcinogenesis. Here, we show that, in hippocampal neurons, NMDA-receptor-dependent activation of calpain induced the cleavage of beta-catenin at the N terminus, generating stable, truncated forms. These beta-catenin fragments accumulated in the nucleus and induced Tcf/Lef-dependent gene transcription. We identified Fosl1, one of the immediate-early genes, as a target of this signaling pathway. In addition, exploratory behavior by mice resulted in a similar cleavage of beta-catenin, as well as activation of the Tcf signaling pathway, in hippocampal neurons. Both beta-catenin cleavage and Tcf-dependent gene transcription were suppressed by calpain inhibitors. These findings reveal another pathway for beta-catenin-dependent signaling, in addition to the canonical Wnt-beta-catenin pathway, and suggest that this other pathway could play an important role in activity-dependent gene expression.
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http://dx.doi.org/10.1016/j.neuron.2007.01.016DOI Listing
February 2007

Synaptic contact dynamics controlled by cadherin and catenins.

Trends Cell Biol 2005 Apr;15(4):216-21

RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.

A synapse is the connection between neurons that joins an axon of one neuron to the dendrite of another. One class of synapses is formed at the contact point between an axon and a small protrusion from a dendrite, called a dendritic spine. These spines are motile and deformable, which indicates that synaptic functions are controlled, at least in part, by their morphological changes. Recent studies show that the cadherin cell-adhesion molecules and their cytoplasmic partners, catenins, can modulate axon-spine contacts in a manner that responds to neural activity. These observations indicate that cadherins, which are essential for general cell-cell adhesion, also play a role in the control of synaptic dynamics.
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http://dx.doi.org/10.1016/j.tcb.2005.02.002DOI Listing
April 2005