Publications by authors named "Aya Koyama"

Hamartomas are tumor-like masses comprising disorganized normal tissue elements. To date, spontaneous hamartomas have been reported in several organs and tissues in rodents but not in the lungs. Here, we report the first case of a hamartoma in the lungs of a 108-week-old female Wistar Hannover rat.

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Ectopic pancreatic tissue can occasionally cause inflammation, hemorrhage, stenosis, and invagination, similar to normal pancreatic tissue; however, tumorigenesis is rare. This case report describes an ectopically observed pancreatic acinar cell carcinoma in the thoracic cavity of a female Fischer (F344/DuCrlCrlj) rat. Histopathologically, polygonal tumor cells with periodic acid-Schiff-positive cytoplasmic eosinophilic granules showed solid proliferation and infrequently formed acinus-like structures.

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A synthetic scheme was developed to derive a modified ribothymidine bearing a 3-(N-methylsulfamoyl)propyl group on 2'-oxygen (T). For synthesis initiation, a nucleophilic attack of 1,2-ethanediol on 5'-protected 2,2'-anhydro-ribothymidine was performed to selectively modify the 2'-position. After protection of the 3'-hydroxy group, the hydroxyethyl group was oxidized to the aldehyde, which was coupled with isobutyl (diethoxyphosphinyl)methanesulfonate through the Horner-Wadsworth-Emmons reaction to yield the sulfonate intermediate.

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Cellular heat stress can cause damage, and significant changes, to a variety of cellular structures. When exposed to chronically high temperatures, yeast cells invaginate vacuolar membranes. In this study, we found that the expression of Atg8, an essential autophagy factor, is induced after chronic heat stress.

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It has been reported that endogenous or exogenous estrogens can affect the immune system, resulting in immune disorders; however, their direct involvement in such conditions remains to be demonstrated. The purpose of this study was to investigate whether estrogen receptors (ER) are directly implicated in pro-pruritic and pro-inflammatory reactions in cutaneous allergy. Initially, enhancement of the pro-inflammatory response by several ER agonists [methoxychlor (MXC), β-estradiol (E2), propylpyrazoletriol (PPT; an ERα agonist), and diarylpropionitrile (DPN; an ERβ agonist)] was examined in vivo using a male BALB/c mouse model of allergic dermatitis induced by toluene-2,4-diisocyanate administration.

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Objective: To determine predictors for virological response to lamivudine, a retrospective-cohort study was designed.

Methods: Seventy HBV positive patients who received lamivudine were classified according to virological response into responders and non-responders. Background conditions and normalization and flare-up of hepatitis were compared using student-t test and chi-square test.

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