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Biomedical subjects

N Yamagata

Publications and source records attributed to N Yamagata.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Gallbladder torsion: case report.

Torsion of the gallbladder (GB) is a rare, acute abdominal condition. The treatment of choice is cholecystectomy. Even with recent advances in radiologic imaging modalities, it is difficult to make a correct preoperative diagnosis of GB torsion. We report a case of GB torsion with a retrospective review of the radiologic findings of magnetic resonance imaging, computed tomography, and ultrasonography. Those findings were compared with the histopathologic findings of the surgical specimen. The radiologic findings in our case were useful for making a preoperative diagnosis of GB torsion. We postulate the characteristic magnetic resonance findings and discuss discrepancies in the evaluations of the GB wall.

Adult↗
PubMedDate not supplied

Modulation of granuloma formation in vitro by endogenous mediators.

We have reported previously that in vitro granulomas are inducible by culturing murine spleen cells in the presence of artificial microparticles, dextran beads, and that macrophages and macrophage-derived cytokines (monokines) including interleukin 1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) play a critical role in the initiation of bead-induced granulomas in vitro. To investigate regulatory mechanisms of granuloma formation, we examined the modulatory effects of various mediators such as IL-1, TNF-alpha, interferon-gamma (IFN-gamma), IL-4, IL-6, transforming growth factor-beta (TGF-beta), dexamethasone and prostaglandin E2 (PGE2) on the development of lesions, because these mediators are known to play a pivotal role in inflammatory responses. The lesions were suppressed by the addition of dexamethasone, PGE2 or certain T cell-derived lymphokines such as IL-4 and IFN-gamma. These results suggest that suppressive signals are different from granulomatogenic cytokines including IL-1 and TNF-alpha and that granulomas are regulated by multi-factor dependent mechanisms.

Animals↗
PubMedDate not supplied

Suppression of pulmonary hypersensitivity granulomas in mice by superoxide dismutase.

Pulmonary hypersensitivity granulomas were induced in immunized mice by the intratracheal injection of antigen-coupled agarose beads. Foreign body lung granulomas were induced in mice by the intratracheal injection of dextran beads. Both lesions developed within 1 day, reached peak intensity within 3 days, and gradually declined in size thereafter. Hypersensitivity granulomas were much larger than foreign body lesions. The lung extracts prepared from mice with hypersensitivity lung granulomas, but not foreign body lesions, contained high levels of superoxide dismutase (SOD) and thiobarbiturate-reactive substances including lipid peroxides. SOD activity and levels of thiobarbiturate-reactive substances in the extracts correlated with sizes of hypersensitive lesions. Hypersensitivity granulomas, but not foreign body lesions, were inhibited by the administration of recombinant human SOD (rh-SOD). Thiobarbiturate-reactive substances were decreased in the lung extracts of mice bearing hypersensitivity granulomas injected with rh-SOD. These results suggest that reactive oxygen intermediates such as superoxide anion may play an important role in the development of hypersensitivity granulomas and that rh-SOD is capable of inhibiting the lesions by its antioxidant action.

Acetylglucosaminidase↗