Publications by authors named "Sassa T"

The transient dynamics of photocurrents for poly((4-diphenylamino)benzyl acrylate) (PDAA)-based photorefractive (PR) polymers sensitized with perylene bisimide derivative N,N'-diisopropylphenyl-1,6,7,12-tetrachloroperylene-3,4,9,10-tetracarboxyl bisimide (PBI) at various composition ratios were studied. The PR polymer included (4-(diphenylamino)phenyl)methanol (TPAOH) photoconductive plasticizer and (4-(azepan-1-yl)-benzylidene) malononitrile nonlinear optical dye as well, which are needed for inducing PR effects. All the photocurrents measured at 640 nm were well simulated by a two-trapping site model considering photocarrier generation and recombination processes of the charge transfer (CT) complex between PBI and PDAA.

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The photorefractive properties of triphenylamine polymer-based composites with various composition ratios were investigated via optical diffraction, response time, asymmetric energy transfer, and transient photocurrent. The composite consisted of a photoconductive polymer of poly((4-diphenylamino)benzyl acrylate), a photoconductive plasticizer of (4-diphenylamino)phenyl)methanol, a sensitizer of [6,6]-phenyl-C61-butyric acid methyl ester, and a nonlinear optical dye of (4-(azepan-1-yl)-benzylidene)malononitrile. The photorefractive properties and related quantities were dependent on the composition, which was related to the glass transition temperature of the photorefractive polymers.

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  • - Increased lactate levels from glycolysis are being studied as potential markers for metabolic changes in neurons, linked to a drop in brain pH, which has been associated with various neuropsychiatric disorders like schizophrenia and autism.
  • - Research shows that these pH and lactate changes are common across different animal models, including those for depression, epilepsy, and Alzheimer's disease, though findings vary, particularly within the autism spectrum.
  • - A large-scale analysis indicated that higher lactate levels correlate with worse working memory performance, suggesting that altered brain chemistry might reflect underlying conditions across multiple disorders.
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Chondroitin, a class of glycosaminoglycan polysaccharides, is found as proteoglycans in the extracellular matrix, plays a crucial role in tissue morphogenesis during development and axonal regeneration. Ingestion of chondroitin prolongs the lifespan of C. elegans.

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  • The epidermis relies on various ceramides to maintain skin permeability, and mutations in genes responsible for synthesizing specific ceramides can lead to conditions like ichthyosis.
  • This study focused on knockout mice with mutations in three key genes to investigate how these changes affected skin barrier function and epidermal ceramide profiles.
  • Results indicated that the severity of skin barrier impairment varied among the gene knockouts, with significant differences in the levels of acylceramides and protein-bound ceramides, suggesting a complex relationship between ceramide composition and skin barrier defects.*
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Purpose: We hypothesized that a giant left atrium may oppress  the posterior left ventricle and aggravate diastolic dysfunction and heart failure. We evaluated the effect of left atrial plication (LAP) on atrial functional mitral regurgitation.

Methods: We retrospectively reviewed patients who underwent LAP for atrial functional mitral regurgitation at our institution between January 2017 and December 2021.

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Purpose: To evaluate the early and long-term outcomes of left ventricular posterior wall plication for ischemic mitral regurgitation.

Methods: Patients with ischemic mitral regurgitation who underwent left ventricular posterior wall plication via right-sided left atriotomy at our institution between 2010 and 2020 were retrospectively reviewed. Cases with normal cardiac function, left ventricular end-systolic diameter < 50 mm, and left ventriculotomy approach were excluded.

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  • Mutations in Lamin A/C disrupt the structure of cardiomyocytes and contribute to dilated cardiomyopathy (DCM) by trapping the transcription factor TEAD1 at the nuclear membrane.
  • Advanced techniques like single-cell RNA sequencing and ATAC-seq were used to explore the molecular mechanisms behind these mutations, revealing an issue with gene expression regulation.
  • Targeting the Hippo pathway shows promise for correcting the gene dysregulation caused by these mutations, suggesting a potential treatment avenue for patients with DCM linked to this specific mutation.
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The permeability barrier present in the oral cavity is critical for protection from infection. Although lipids have properties suitable for permeability barrier formation, little is known about their role in oral barrier formation. Here, we show the presence of ω-O-acylceramides (acylceramides) and protein-bound ceramides, which are essential for the formation of permeability barriers in the epidermis, in the oral mucosae (buccal and tongue mucosae), esophagus, and stomach in mice.

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Spinocerebellar ataxias (SCAs) are autosomal dominant diseases characterized by cerebellar atrophy and ataxia. The SCA subtype SCA34 is caused by specific mutations in the gene , which encodes a fatty acid (FA) elongase that synthesizes ultra-long-chain (ULC; ≥C26) FAs. However, the pathogenesis and molecular mechanism that confers dominant inheritance remains unknown.

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  • This study investigates how the heart changes after a heart attack (myocardial infarction) by analyzing gene expression in mice.
  • Researchers discovered that genes related to mechanical stress are active in a specific area (the border zone) around the damaged tissue and are key to how the heart remodels post-MI.
  • They found that a gene called Csrp3 is particularly important, as manipulating its levels can help prevent harmful cardiac remodeling, suggesting it plays a protective role in heart recovery.
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Objectives: Our goal was to evaluate the surgical and conservative outcomes of acute type A aortic dissection with a thrombosed false lumen of the ascending aorta in elderly patients.

Methods: Patients older than 75 years with acute type A aortic dissection admitted to our hospital from October 2011 to December 2020 were reviewed retrospectively, including those with the noncommunicating type without malperfusion and low physical capacity prehospitalization.

Results: Sixty-six patients were enrolled consecutively in the medical (M, n = 30) and surgical (S, n = 36) groups.

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  • - Sjögren-Larsson syndrome (SLS) is a genetic disorder linked to the ALDH3A2 gene, characterized by skin issues like ichthyosis and problems with skin barrier formation due to disrupted ceramide levels.
  • - Genetic analysis of an SLS patient revealed mutations in the ALDH3A2 gene and significantly lower levels of acylceramides and several nonacylated ceramides in comparison to healthy controls.
  • - The study concludes that the reduced levels of acylceramides likely contribute to the skin symptoms of SLS, with other ceramide class reductions possibly playing a role as well.
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Tissue fibrosis and organ dysfunction are hallmarks of age-related diseases including heart failure, but it remains elusive whether there is a common pathway to induce both events. Through single-cell RNA-seq, spatial transcriptomics, and genetic perturbation, we elucidate that high-temperature requirement A serine peptidase 3 (Htra3) is a critical regulator of cardiac fibrosis and heart failure by maintaining the identity of quiescent cardiac fibroblasts through degrading transforming growth factor-β (TGF-β). Pressure overload downregulates expression of Htra3 in cardiac fibroblasts and activated TGF-β signaling, which induces not only cardiac fibrosis but also heart failure through DNA damage accumulation and secretory phenotype induction in failing cardiomyocytes.

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Transcatheter aortic valve implantation (TAVI) represents the standard of care for relieving aortic stenosis in high-risk patients for surgery. The transfemoral approach is preferable with respect to invasiveness, but is often difficult in patients with complex vascular structures. Recently, the clinical application of advanced visualization and guidance technology with three-dimensional computed tomography (3D-CT) during TAVI has received considerable attention.

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Introduction: Next generation sequencing technologies allow detection of very rare pathogenic gene variants and uncover cerebral palsy. Herein, we describe two siblings with cerebral palsy due to ELOVL1 splice site mutation in autosomal recessive manner. ELOVL1 catalyzes fatty acid elongation to produce very long-chain fatty acids (VLCFAs; ≥C21), most of which are components of sphingolipids such as ceramides and sphingomyelins.

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Systolic anterior motion of the anterior mitral leaflet with anterior displacement of the coaptation site of the bi-leaflets due to mitral annular calcification on the posterior side, causing left ventricular outflow tract obstruction, is rare. We report the case of a 72-year-old woman with exertional dyspnea due to systolic anterior motion who underwent surgical repair to decalcify the mitral annular calcification and mitral valve repair. Hence, the systolic anterior motion, mitral valve regurgitation, and symptoms improved significantly.

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TAVI is an established therapy for patients with severe aortic stenosis. Rapid or control pacing is necessary for TAVI, and most centers are familiar with right ventricular (RV) pacing. Although there are several reports on the efficacy and safety of LV pacing, they are still few.

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There are few reports on the current awareness and status of venous ultrasonography, including the number of specialists who perform this procedure, in a specific regional area in Japan. This cross-sectional survey study was conducted in Kumamoto Prefecture from October 2018 to March 2019. Of the 366 medical institutions providing cardiology services in Kumamoto Prefecture, 259 (101 general hospitals, 158 small clinics) responded to our questionnaire.

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Article Synopsis
  • Sjögren-Larsson syndrome (SLS) is a genetic disorder linked to the fatty aldehyde dehydrogenase gene ALDH3A2, which affects skin health.
  • Research using double-knockout (DKO) mice showed that the absence of this gene led to skin issues, including hyperkeratosis and reduced ability to maintain skin barrier function due to lower levels of important skin lipids called acylceramides.
  • The study suggests that fatty aldehydes accumulating in these mice may inhibit the enzyme responsible for producing acylceramides, shedding light on the molecular mechanisms behind SLS skin symptoms.
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A lipid layer consisting of meibum lipids exists in the tear film and functions in preventing dry eye disease. Although the meibum lipids include diverse lipid classes, the synthesis pathway and role of each class remain largely unknown. Here, we created single and double knockout (KO and DKO, respectively) mice for the two acyl-CoA wax alcohol acyltransferases ( and ) and investigated their dry eye phenotypes and meibum lipid composition.

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