Publications by authors named "Ryotaro Yamamoto"

Background: Intraductal papillary mucinous neoplasm is occasionally detected in the preoperative images of patients with gastrointestinal malignancies. Despite numerous studies examining the incidence of extrapancreatic malignancies in patients with intraductal papillary mucinous neoplasm, limited data exist on the prevalence of intraductal papillary mucinous neoplasm in those with gastrointestinal malignancies. Given that intraductal papillary mucinous neoplasm is a known risk factor for pancreatic cancer, this study aimed to evaluate the prevalence of intraductal papillary mucinous neoplasm in patients who underwent radical surgery for extrapancreatic gastrointestinal malignancies and its impact on pancreatic cancer development.

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Nonocclusive mesenteric ischemia (NOMI) is a life-threatening disorder. Early diagnosis is challenging because NOMI lacks specific symptoms. A 52-year-old man who received extended cholecystectomy with Roux-en-Y hepaticojejunostomy for gallbladder cancer (GBC) presented to our hospital with nausea and vomiting.

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Article Synopsis
  • The study investigates gallbladder fossa nodularity (GBFN) in patients with alcoholic liver disease (ALD), proposing that reduced blood flow from portal veins due to cholecystic venous drainage (CVD) may cause this nodularity to arise, sparing affected liver tissue from alcohol-related damage.
  • Researchers analyzed CT scans from 45 ALD patients and 46 with chronic hepatitis C (CHC), noting that GBFN was more common and higher in grade among ALD patients; they also found significant correlations with alcohol consumption and liver function indicators.
  • The findings suggest GBFN could indicate liver tissue that avoids alcohol exposure, offering a specific but low-sensitivity marker for
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Methods for intracellular protein photoactivation have been studied to elucidate the spatial and temporal roles of proteins of interest. In this study, an intracellular protein photoactivation method was developed using sterically bulky caging. The protein of interest was modified with biotin via a photocleavable linker, and then conjugated with streptavidin to sterically block the protein surface for inactivation.

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  • This study aimed to determine if extracellular volume fraction (ECV) from iodine-based imaging during dual-energy liver CT (DECT) can effectively estimate liver fibrosis severity.
  • Researchers analyzed data from 52 patients with chronic liver disease, comparing ECV results from different methods to liver stiffness measurements obtained through MRI.
  • The results showed that ECV values derived from DECT images correlated well with liver stiffness and histological fibrosis grades, indicating that ECV is a valuable tool for assessing liver fibrosis.
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In recent years, photodynamic therapy (PDT) has been approved for treating various medical conditions, including cancer. PDT is a treatment that employs a particular drugs, called photosensitizers which work along with specific light source. The growth of this medical industry is expanding as it is another promising alternative to treat cancer which lessen the burden of treatments in patients.

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Coumarins are derived via the phenylpropanoid pathway in plants. The 2H-1-benzopyran-2-one core structure of coumarins is formed via the ortho-hydroxylation of cinnamates, trans/cis isomerization of the side chain, and lactonization. Ortho-hydroxylation is a key step in coumarin biosynthesis as a branch point from lignin biosynthesis; however, ortho-hydroxylation of cinnamates is not yet fully understood.

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In the present paper, we systematically examined the ion-pairing effect in low-water-content charged membranes. Cation- and anion-exchange membranes with various water contents and homogeneous fixed-charge distribution were prepared by radical copolymerization and then characterized by membrane potential measurements. The experimental results were analyzed by our recently developed theoretical model (Yamamoto, R.

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The membrane potential across anion-exchange membranes in H2SO4 and Na2SO4 solutions was measured, and the experimental results were fitted to the theory in the 2-1 electrolyte system based on the Donnan equilibrium and the Nernst-Planck flux equations. For the Na2SO4 solution, the Donnan potential makes a significant contribution to the membrane potential, but for the H2SO4 solution, the diffusion potential significantly contributes to the membrane potential. The diffusion potential has a greater contribution to the membrane potential across AEM-2 with a high water content than that across AEM-1.

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