Publications by authors named "Kozuka K"

Background And Study Aims: Prophylactic clip closure after colorectal endoscopic submucosal dissection (ESD) among patients on anticoagulants is of uncertain effectiveness in reducing delayed bleeding (DB) risk. We aimed to assess the effect of prophylactic clip closure in preventing DB after colorectal ESD among patients on anticoagulants.

Patients And Methods: We used the ABCD-J study database, a large-scale multicenter study analyzing DB among 34,455 colorectal ESD cases from 47 Japanese institutions.

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Because of increased risks of cardiovascular disease and death, patients with hyperphosphatemia receiving maintenance dialysis are advised to limit phosphorus consumption and are prescribed phosphate binders in an effort to better control serum phosphate concentrations. Because of large pill size, pill burden, and tolerability issues, phosphate binder adherence is relatively poor. On ingestion, phosphate is absorbed from the intestine via transcellular or paracellular transport.

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Increased intestinal permeability has been identified as one of the many pathophysiological factors associated with the development of irritable bowel syndrome (IBS), a common disorder of gut-brain interaction. The layer of epithelial cells that lines the intestine is permeable to a limited degree, and the amount of paracellular permeability is tightly controlled to enable the absorption of ions, nutrients, and water from the lumen. Increased intestinal permeability to macromolecules can be triggered by a variety of insults, including infections, toxins from food poisoning, or allergens, which in turn cause an inflammatory response and are associated with abdominal pain in patients with IBS.

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Photochromism through excited-state intermolecular proton transfer (ESInterPT) processes based on keto-enol tautomerization was found in phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2 in a glassy matrix at 77 K: the colorless solutions of enol forms PD1-E and PD2-E at 298 K transformed into orange-colored solutions of keto forms PD1-K and PD2-K upon photoirradiation ( = 385 nm) at 77 K. Furthermore, this report is the first to achieve the single-crystal X-ray structural analyses of phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2, since the report on the synthesis of PD1 70 years ago. Indeed, it was found that PD1 and PD2 molecules exist in the keto form (PD1-K) and the enol form (PD2-E), respectively, in the crystal, and the neighboring PD1-K and PD2-E molecules are linked by one-dimensional intermolecular NH⋯O and OH⋯N hydrogen bonding, respectively.

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Background: Patients with irritable bowel syndrome with constipation (IBS-C) experience persistent abdominal pain, a common symptom leading to greater healthcare utilization and reports of treatment non-response. Clinically significant improvements in abdominal pain were observed in clinical trials of tenapanor, a first-in-class inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3), for the treatment of IBS-C in adults.

Aim: This narrative review reports the current knowledge about visceral hypersensitivity as a mechanism for abdominal pain in patients with IBS-C and explores the published evidence for hypothesized mechanisms by which tenapanor may reduce visceral hypersensitivity leading to the observed clinical response of decreased abdominal pain.

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Article Synopsis
  • The pathogenesis of irritable bowel syndrome (IBS) involves factors like increased intestinal permeability and visceral hypersensitivity, leading to symptoms like abdominal pain and severity of the condition.
  • Tenapanor, an FDA-approved treatment for IBS with constipation, has shown to improve bowel motility and alleviate IBS-related pain, though the precise mechanism of action is not fully understood.
  • Research indicates that tenapanor reduces pain by improving intestinal barrier function and decreasing permeability, which in turn decreases pain signaling in the gut.
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Article Synopsis
  • The study analyzed delayed bleeding rates after colorectal endoscopic submucosal dissection in patients taking direct oral anticoagulants (DOACs) and compared them to patients on warfarin.
  • Among different DOACs, dabigatran had the highest delayed bleeding rate, whereas rivaroxaban showed a significantly lower rate than warfarin.
  • Risk factors for delayed bleeding in the DOAC group included heparin bridging therapy, rectal lesion location, and longer procedure times.
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Aim: Phosphorus is a critical constituent of bone as a component of hydroxyapatite. Bone mineral content accrues rapidly early in life necessitating a positive phosphorus balance, which could be established by a combination of increased renal reabsorption and intestinal absorption. Intestinal absorption can occur via a transcellular pathway mediated by the apical sodium-phosphate cotransporter, Slc34a2/NaPiIIb or via the paracellular pathway.

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Objectives: No protocol for esophagogastroduodenoscopic examination of the duodenum has been established. We examined the feasibility and ability to detect neoplasms of a novel duodenal examination protocol.

Methods: This was a two-facility, prospective, observational study.

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  • Esophagogastroduodenoscopy (EGD) procedures create aerosols, posing a challenge for preventing COVID-19 spread in endoscopy units.
  • A study involving 61 patients tested the effectiveness of an extraoral suction device to reduce aerosol diffusion during EGD exams.
  • Results showed the device significantly decreased the diffusion of larger aerosols (3, 5, and 10 μm) but increased the spread of smaller aerosols (0.3 and 0.5 μm), indicating it’s only partially effective in protecting examiners.
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Background And Aim: To evaluate the efficacy and safety of a grasping-type knife, called Clutch Cutter (CC), for colorectal endoscopic submucosal dissection (C-ESD).

Methods: This was a randomized prospective study. Patients who underwent C-ESD for colorectal neoplasms >20 mm and <50 mm in size were enrolled, dividing into two groups: ESD using needle type of dual knife alone (D-group) and circumferential incision using dual knife followed by submucosal dissection using CC (CC-group).

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Sequence-based protein design approaches are being adopted to generate highly functional enzymes; however, screening the enzymes remains a time-consuming task. In this study, by analyzing the enzymatic properties of four ancestral meso-2,6-diaminopimelate dehydrogenases (AncDAPDHs), AncDAPDH-N1, -N2, -N3, and -N4, we attempted to define a new index parameter that is helpful for efficiently screening the enzymes. Biochemical and thermodynamic analyses indicated that only AncDAPDH-N4 exhibited greater thermal stability than and activity similar to those of native DAPDHs.

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Background: The management of delayed bleeding after gastric endoscopic submucosal dissection (ESD) is currently an important issue because of recent increases in the number of patients on antithrombotic therapy. Artificial ulcer closure has been shown to prevent delayed complications in the duodenum and colon. However, its effectiveness in cases involving the stomach remains unclear.

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Background: The recently developed endoscopic full-thickness resection technique requires reliable closure. The main closure methods are the purse-string suture (PSS) technique and over-the-scope clip (OTSC) technique; however, basic data on the closure strength of each technique are lacking. This study was performed to compare the closure strengths of these two methods in an ex vivo porcine model.

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Introduction: Mucosal defect closure after colorectal endoscopic submucosal dissection (ESD) may prevent post-ESD adverse events. Delayed bleeding is a particular concern in the rectum due to the presence of numerous blood vessels. However, rectal defect closure often fails due to the thick rectal wall.

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We present herein the design, synthesis, and optimization of gut-restricted inhibitors of Na/H exchanger isoform 3 (NHE3). NHE3 is predominantly expressed in the kidney and gastrointestinal tract where it acts as the major absorptive sodium transporter. We desired minimally systemic agents that would block sodium absorption in the gastrointestinal tract but avoid exposure in the kidney.

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Background: We examined the efficacy of a novel endoscopic ligation technique with O-ring closure (E-LOC) to prevent bleeding after gastric endoscopic submucosal dissection (ESD) under antithrombotic therapy.

Methods: This single-center prospective study involved consecutive patients who were taking antithrombotic agents and underwent gastric ESD. E-LOC was performed by anchoring the nylon loop with hemoclips on both defect edges and/or the exposed muscle layer, and using O-ring band ligation around these deployed clips.

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Esophagogastroduodenoscopy (EGD) has a high risk of virus transmission during the current coronavirus disease 2019 era, and preventive measures are under investigation. We investigated the effectiveness of a newly developed patient-covering negative-pressure box system (Endo barrier) (EB) for EGD. Eighty consecutive unsedated patients who underwent screening EGD with EB use were prospectively enrolled.

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Glutamate decarboxylase (GAD) catalyses the decarboxylation of L-glutamate to gamma-aminobutyric acid (GABA). Improvement of the enzymatic properties of GAD is important for the low-cost synthesis of GABA. In this study, utilizing sequences of enzymes homologous with GAD from lactic acid bacteria, highly mutated GADs were designed using sequence-based protein design methods.

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Pooled gastric residues involving blood clots and food interrupt appropriate endoscopic intervention, leading to poor outcomes in endoscopic hemostasis and lifesaving. However, procedures and devices that enable the effective removal of gastrointestinal residues remain unsatisfactory. This study aimed to evaluate the efficacy and safety of our developed suction method in ex vivo and in vivo studies.

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Consensus design (CD) is a representative sequence-based protein design method that enables the design of highly functional proteins by analyzing vast amounts of protein sequence data. This study proposes a partial consensus design (PCD) of a protein as a derivative approach of CD. The method replaces the target protein sequence with a consensus sequence in a secondary-structure-dependent manner (i.

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