Publications by authors named "Masanori Nakamura"

Article Synopsis
  • Hypertension leads to thickening of the aortic wall as the body tries to restore normal stress levels.
  • Researchers proposed that stress fibers (SFs) in smooth muscle cells (SMCs) transmit this mechanical tension to the nucleus, influencing cell response.
  • By studying thoracic aortas from different rat models (Wistar Kyoto and spontaneously hypertensive), they found that SF strain varies with changes in blood pressure, confirming SFs act as mechanosensors to respond to hypertensive conditions.
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Capillary refill time (CRT) is a widely used noninvasive measure of cardiovascular health. Despite its widespread diagnostic utility, it has several limitations, particularly its low sensitivity for certain conditions, because factors such as the contraction and relaxation of distal blood vessels can influence CRT readings. This study was performed to explore the relationships between CRT and distal blood flow.

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This paper discusses the impact of pump-phase noise in the χ-based optical parametric amplification process on the phase-conjugated idler. We show that the dispersive fiber propagation of the phase-conjugated idler causes the optically enhanced pump-phase noise (OEPN) effect including a group-velocity jitter. The signal penalty caused by the OEPN in the mid-link optical phase conjugation systems was quantified analytically and proved by numerical simulations.

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The Phenotypic states of vascular smooth muscle cells (SMCs) are essential to understanding vascular pathophysiology. SMCs in vessels generally express a specific set of contractile proteins, but decreased contractile protein expression, indicating a phenotypic shift, is a hallmark of vascular diseases. Recent studies have suggested the relation of abnormally high wall shear stress (WSS) of approximately 20 Pa with the aortic disease pathogenesis.

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Article Synopsis
  • The study investigated the long-term outcomes of patients with hepatitis C virus (HCV)-related liver cancer (HCC) who underwent surgery, focusing on those who achieved sustained virologic response (SVR) from antiviral therapy versus those who didn't.
  • A total of 216 patients were analyzed, revealing that those with pre- or post-SVR had better liver health and significantly improved overall survival (OS) and recurrence-free survival (RFS) compared to the non-SVR group.
  • Results suggested that achieving SVR, particularly through direct-acting antiviral (DAA) therapy, was strongly linked to lower recurrence rates and increased survival rates after surgical resection of HCC.
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Article Synopsis
  • The study investigates distal stent graft-induced new entry (dSINE), a complication of the frozen elephant trunk (FET) procedure, and aims to understand its underlying mechanisms through simulation.
  • Using finite element analysis and computational fluid dynamics, it examines how different sizes of FET affect stress and blood flow in the aorta.
  • Findings indicate that both oversized and undersized FETs can contribute to dSINE through mechanisms like increased circumferential stress and wall shear stress, suggesting that simply choosing a smaller FET size may not prevent this complication.
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Objectives: One possible reason for the long-term patency of no-touch (NT) saphenous vein grafts (SVG) is the preservation of the vasa vasorum in the adventitia/perivascular adipose tissue (PAT). We investigated the vasa vasorum of the NT SVG in vivo using frequency-domain optical coherence tomography (FD-OCT), performed qualitative and quantitative analyses and compared them with the conventional SVG.

Methods: An FD-OCT study was performed on 14 SVG at the postoperative coronary angiography 1-2 weeks postoperatively (NT group, n = 9; conventional group, n = 5).

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Thrombus formation plays a crucial role in the clinical treatment of certain diseases. In conditions such as aortic dissection and cerebral aneurysm, complete thrombus occlusion in the affected region is desired to reduce blood flow into the false lumen or aneurysm sac, leading to a decrease in the tension exerted on the vascular wall and making it less likely to rupture. However, desired thrombosis sometimes fails to occur.

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Background And Purpose: Intracranial aneurysm growth is a significant risk factor for rupture; however, a few aneurysms remain unruptured for long periods, even after growth. Here, we identified hemodynamic features associated with aneurysmal rupture after growth.

Materials And Methods: We analyzed nine middle cerebral artery aneurysms that grew during the follow-up period using computational fluid dynamics analysis.

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Purpose: Laparoscopic hepatectomy (LH) is reported to cause less bleeding than open hepatectomy (OH) in obese patients; however, there are no reports addressing this issue in terms of body size-corrected bleeding.

Methods: The subjects of this study were 31 obese and 149 non-obese patients who underwent LH and 32 obese and 245 non-obese patients who underwent OH. Bleeding corrected for body surface area (C-BL) was compared between the obese and non-obese patients who underwent each procedure.

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Article Synopsis
  • * It is found that phase noise affects only the idler signal and not the amplified signal, with potential implications for signal quality in digital coherent fiber transmission systems.
  • * A method is proposed to mitigate this phase noise by using correlated pump lights between wavelength converters, helping to maintain signal integrity at high data rates (32, 64, and 96 Gbaud).
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Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH.

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Computational fluid dynamics was performed to simulate haemodynamics of type B aortic dissection complicated by mesenteric malperfusion caused by dynamic obstruction in a 70-year-old man. Streamline analysis showed disappearance of antegrade flow in the false lumen of the descending aorta and attenuation of intermittent flap-induced disruption of visceral vessel perfusion after entry coverage. Quantitative analysis showed endovascular repair increased perfusion volume of the coeliac artery and superior mesenteric artery by 55.

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Objective: This study aimed to clarify the association between hospital-acquired disability (HAD) and prognosis in older patients who underwent cardiac surgery.

Methods: This single-center, retrospective, observational study included 141 patients aged ≥65 years who underwent cardiac surgery at our hospital from November 2016 to August 2021. The primary endpoint of this study was the occurrence of major adverse cardiac and cerebrovascular events (MACCEs) within 2 years of hospital discharge.

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Aortic dissection (AD) is a life-threatening tear of the vascular tissue with creation of a false lumen. To explore the mechanism underlying this tissue tear, this study investigated the delamination strength of AD model rats and the histological composition of the aorta at various stages of AD development. SD rats were administrated beta-amino propionitrile for 0 (Control), 3 (Pre-dissection), and 6 (Dissection) weeks.

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Objectives: Histidine decarboxylase (HDC), a histamine synthase, is expressed in various tissues and is induced by proinflammatory cytokines such as TNFα. As they age, C57BL/6 mice show auto-antibody deposition and lymphocyte infiltration into various tissues, including salivary glands. However, the mechanism underlying cell infiltration and the change in HDC expression in salivary glands with aging remain unclear.

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The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole.

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Background: Small intestine carcinoma (SIC) cases in Japan have recently been treated with chemotherapy according to colorectal carcinoma classification, while papilla of Vater carcinoma (PVC) cases according to cholangiocarcinoma (CHC) classification. However, few research reports support the molecular genetic validity of these therapeutic choices.

Patients And Methods: Here, we investigated the clinicopathological and molecular genetic factors of SIC and PVC.

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Purpose: An animal model of laparoscopic hepatectomy showed that bleeding from the hepatic vein is influenced by airway pressure. However, there are little research reports on how airway pressure leads to risks in clinical practice. The main objective of this study was to investigate the impact of preoperative forced expiratory volume % in 1 s (FEV1.

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We sought to identify and quantitatively analyze calcium oxalate (CaOx) kidney stones on the order of micrometers, with a focus on the quantitative identification of calcium oxalate monohydrate (COM) and dihydrate (COD). We performed Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), and microfocus X-ray computed tomography measurements (microfocus X-ray CT) and compared their results. An extended analysis of the FTIR spectrum focusing on the 780 cm-1 peak made it possible to achieve a reliable analysis of the COM/COD ratio.

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Atrial fibrillation (AF) induces cardioembolic stroke due to intracardiac fibrin thrombus formation. Although it is well established that a cardioembolic stroke affects the anterior circulation more frequently than it affects the posterior circulation, the destination where the thrombi migrate when cardioembolic stroke occurs in each patient remains unclear. We present a critical case wherein a bilateral internal carotid artery (ICA) territory infarction was diagnosed in a patient with AF who apparently developed nearly simultaneous occlusion in the ICAs bilaterally.

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Maternal overnutrition affects offspring susceptibility to nonalcoholic steatohepatitis (NASH). Male offspring from high-fat diet (HFD)-fed dams developed a severe form of NASH, leading to highly vascular tumor formation. The cancer/testis antigen HORMA domain containing protein 1 (HORMAD1), one of 146 upregulated differentially expressed genes in fetal livers from HFD-fed dams, was overexpressed with hypoxia-inducible factor 1 alpha (HIF-1alpha) in hepatoblasts and in NASH-based hepatocellular carcinoma (HCC) in offspring from HFD-fed dams at 15 weeks old.

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In response to hydrostatic pressure, the cation channel transient receptor potential vanilloid 1 (TRPV1) is essential in signaling pathways linked to glaucoma. When activated, TRPV1 undergoes a gating transition from a closed to an open state that allows the influx of Ca ions. However, the gating mechanism of TRPV1 in response to hydrostatic pressure at the molecular level is still lacking.

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Article Synopsis
  • Tension in stress fibers (SFs) is crucial for various biological processes like cell movement and protein synthesis.
  • Previous research methods using live cells may have inaccurately measured contraction forces due to increased polarized light retardation.
  • This study confirmed that SF contraction leads to increased light retardation regardless of cell activity and found that the density of SFs increases as they contract, leading to a reduction in diameter while maintaining nearly constant length.
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