Publications by authors named "Yoshiyuki Rikitake"

The relationship between the concomitant use of immune checkpoint inhibitors (ICIs) and elevated prothrombin time-to-international standard ratio (PT-INR) in patients receiving warfarin remains unclear. In the present study, 26 patients treated with ICIs during warfarin therapy were examined for increases in PT-INR within 60 d of ICI administration. Of these patients, 13 developed Grade 2 or higher PT-INR elevations, 5 of which required the immediate administration of vitamin K.

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Article Synopsis
  • Ultraviolet B (UV-B) irradiation, particularly at the specific wavelength of 282 nm, has been found to reduce atherosclerosis by affecting immune responses and inflammation.
  • In experiments with atherosclerosis-prone mice, exposure to 282 nm UV-B led to a significant decrease in aortic plaque formation and inflammation, unlike other wavelengths (301 nm and 312 nm).
  • The beneficial effects of 282 nm UV-B were linked to an increase in regulatory T cells and a favorable shift in lipid mediators, suggesting that this form of UV-B therapy may be a promising treatment for atherosclerosis.
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Macrophage infiltration is a characteristic feature of atherosclerotic plaque progression. Since liposomes containing 1,2-distearoyl-sn-glycero-3-phosphoglycerol (DSPG) are efficiently phagocytosed by macrophages, we deduced that radiolabeled liposomes containing DSPG could potentially be used for nuclear imaging of vulnerable atherosclerotic plaques. Indium-111 (In)-labeled liposomes containing different ratios of DSPG were developed with a high labeling efficiency.

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Alzheimer's disease (AD) is among the most prevalent age-related neurodegenerative diseases. Endothelial cell (EC) senescence was discovered in the AD brain, but its function in AD pathogenesis was unidentified. Here we created an AD mouse model with EC senescence (APP/PS1;TERF2DN mice) by intercrossing APP/PS1 mice with Tie2 promoter-driven dominant negative telomeric repeat-binding factor 2 transgenic mice (TERF2DN-Tg mice).

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Article Synopsis
  • Doctors studied what causes brain bulges called intracranial aneurysms (IAs), which can lead to serious bleeding.
  • They found that many of these IAs have changes in certain genes that affect how the cells work, discovering 16 mutated genes in 92% of the cases they looked at.
  • One gene mutation was shown to make blood vessels grow bigger in mice, suggesting that these findings could help create new treatments to prevent or fix IAs.
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Aim: To clarify the incidence and risk factors of infusion-related reactions (IRRs) caused by trastuzumab in breast cancer patients and verify the preventive effects of dexamethasone.

Methods: All breast cancer patients newly treated with trastuzumab at the Osaka Medical and Pharmaceutical University Hospital from 1 January 2017 to 31 December 2020 were included. The electronic medical records were retrospectively reviewed.

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In the brain, neurons, glial cells, vascular endothelial cells (ECs), and mural cells form a functional structure referred to as the neurovascular unit (NVU). The functions of the NVU become impaired with aging. To gain insight into the mechanism underlying the aging-related changes in the NVU, we characterized in the present study the gliovascular interface in transgenic mice expressing a dominant-negative form of the telomeric repeat-binding factor 2 (TERF2) specifically in ECs using the Tie2 promoter.

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For proper intracellular vesicle transport, it is essential for transport vesicle membranes to fuse with the appropriate target membranes. Ykt6 is a SNARE protein with functions in diverse vesicle transport pathways, including secretory, endocytotic and autophagic pathways. To exert these functions, the association of Ykt6 with vesicle membranes and the change of its conformation from closed to open play key roles.

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Compelling evidence suggests a crucial role for Foxp3 regulatory T cells (Tregs) in the control of atherosclerosis. Although suppression of pro-inflammatory CD4 T cell immune responses is supposed to be important for athero-protective action of Foxp3 Tregs, few studies have provided direct evidence for this protective mechanism. We investigated the impact of Foxp3 Treg depletion on CD4 T cell immune responses and the development of atherosclerosis under hypercholesterolemia.

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Atherosclerotic diseases, including ischemic heart disease and stroke, are a main cause of mortality worldwide. Chronic vascular inflammation via immune dysregulation is critically involved in the pathogenesis of atherosclerosis. Accumulating evidence suggests that regulatory T cells (Tregs), responsible for maintaining immunological tolerance and suppressing excessive immune responses, play an important role in preventing the development and progression of atherosclerosis through the regulation of pathogenic immunoinflammatory responses.

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The efficacy of cisplatin (CDDP) has been demonstrated in the treatment of various cancers as monotherapy and combination therapy with immunotherapy. However, acquired CDDP resistance is a major obstacle to successful treatment. In the present study, the mechanisms underlying acquired CDDP resistance were examined using ACR20 cells, which are CDDP‑resistant cells derived from A549 lung cancer cells.

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Chronic inflammation caused by pathogenic immune response is crucial in the pathogenesis of kidney disease. In particular, T-cell-mediated adaptive immune responses evoke pathogenic immunoinflammatory responses and contribute to kidney injury (KI). Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), a potent negative regulator of T-cell immune responses, protects against immunoinflammatory diseases of the arteries such as atherosclerosis and abdominal aortic aneurysm.

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Objective: Chondroitin sulfate proteoglycans are the primary constituents of the macrophage glycosaminoglycan and extracellular microenvironment. To examine their potential role in atherogenesis, we investigated the biological importance of one of the chondroitin sulfate glycosaminoglycan biosynthesis gene, ChGn-2 (chondroitin sulfate -acetylgalactosaminyltransferase-2), in macrophage foam cell formation. Approach and Results: ChGn-2-deficient mice showed decreased and shortened glycosaminoglycans.

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The apelin (APJ) receptor was originally cloned as a gene encoding a putative G protein-coupled receptor related to angiotensin receptor type I. To date, two endogenous peptide ligands for APJ have been identified: apelin and elabela/Toddler. The apelin/APJ system regulates blood pressure and vascular tone.

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Background/aim: To prevent infusion-related reactions (IRRs), H1-antihistamines (HAT) are recommended as a premedication for monoclonal antibodies, such as Ramucirumab (RAM), even though there are HAT-related side effects, such as drowsiness and dizziness. Here, we investigated the safety of HAT-free RAM regimens in patients with solid cancer.

Patients And Methods: We retrospectively reviewed the patients with solid cancer receiving RAM without HAT at Osaka Medical College Hospital between 2015 and 2019.

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What Is Known And Objective: Levetiracetam is an antiepileptic drug with good tolerability that is used for focal and generalized epilepsy as well as acute treatment of status epilepticus; it is also a first-line antiepileptic drug for patients with concomitant medical conditions. The effect of blood levetiracetam concentration on its efficacy and safety in Japanese patients with epilepsy is unknown.

Methods: This retrospective cohort study compared the efficacy and safety of levetiracetam alone and in combination with other antiepileptic drugs in 255 outpatients with epilepsy treated with levetiracetam.

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Vascular inflammation via T-cell-mediated immune responses has been shown to be critically involved in the pathogenesis of abdominal aortic aneurysm (AAA). T-cell coinhibitory molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is known to act as a potent negative regulator of immune responses. However, the role of this molecule in the development of AAA remains completely unknown.

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Nonalcoholic steatohepatitis (NASH) progresses from nonalcoholic fatty liver disease (NAFLD); however, efficacious drugs for NASH treatment are lacking. Sodium alginate (SA), a soluble dietary fiber extracted from brown algae, could protect the small intestine from enterobacterial invasion. NASH pathogenesis has been suggested to be associated with enterobacterial invasion, so we examined the effect of SA on methionine- and choline-deficient (MCD) diet-induced steatohepatitis in mice (the most widely-used model of NASH).

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Here, we developed a novel in vitro co-culture model, in which process-bearing astrocytes and isolated cerebral microvessels from mice were co-cultured. Astrocytes formed contacts with microvessels from both adult and neonatal mice. However, concentrated localization of the immunofluorescence signal for aquaporin-4 (AQP4) at contact sites between perivascular endfoot processes and blood vessels was only detected with neonatal mouse microvessels.

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Cisplatin (CDDP) is widely used as an anti-cancer platinum agent but its therapeutic efficacy is limited by acquired drug resistance. To develop a new therapeutic strategy that could overcome this resistance, it is important to characterize CDDP-resistant cancer cells. Here we established human lung cancer A549 cell-derived low- and high-grade CDDP-resistant sublines, termed ACR4 and ACR20 cells, by stepwise increasing CDDP concentrations up to 4 and 20 μM, respectively.

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In the central nervous system, astrocytes extend endfoot processes to ensheath synapses and microvessels. However, the mechanisms underlying this astrocytic process extension remain unclear. A limitation of the use of 2D cultured astrocytes for such studies is that they display a flat, epithelioid morphology, with no or very few processes, which is markedly different from the stellate morphology observed in vivo.

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Objective: We previously reported that afadin, an actin filament-binding protein, regulated vascular endothelial growth factor-induced angiogenesis. However, the underlying molecular mechanisms are poorly understood. Here, we investigated the mechanisms of how Rho-associated kinase is activated in afadin-knockdown human umbilical vein endothelial cells (HUVECs) and how its activation is involved in defects of vascular endothelial growth factor-induced network formation and migration of the cells.

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Background: Exosomes, small-membrane vesicles, are secreted by cells and include several types of proteins and nucleic acids. Exosomes transfer cellular information derived from donor cells and are involved in various physiological and pathological events, such as organ-specific metastasis. Elucidating the exosome uptake mechanisms is important for understanding the progression processes of organ-specific metastasis.

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Background: Pathogenic immune responses are known to play an important role in abdominal aortic aneurysm (AAA) development. Ultraviolet B (UVB) irradiation has been demonstrated to have therapeutic potential not only for cutaneous diseases but also for systemic inflammatory diseases in mice by suppressing immunoinflammatory responses. We investigated the effect of UVB irradiation on experimental AAA.

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We have reported that knockdown of Necl-4 decreases vascular endothelial growth factor (VEGF)-induced phosphorylation of extracellular signal-regulated kinase (ERK) without affecting phosphorylation of VEGF receptor 2 (VEGFR2) in sparsely cultured human umbilical vein endothelial cells (HUVECs). However, the underlying molecular mechanism is unknown. Compared with control HUVECs, VEGF-induced phosphorylation of phospholipase Cγ (PLCγ), c-Raf, mitogen-activated protein kinase/ERK kinase (MEK) and ERK were all inhibited in Necl-4-knockdown HUVECs.

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