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115 results on '"OHARA, Susumu"'

33. Characterization of dense artificial connective tissues generated in a newly designed bioreactor.

Author

Iwashiro, Hironobu, Hosoya, Satoshi, Hirai, Kazuya, Mima, Takehiko, Ohashi, Shihoka, Aihara, Takashi, Ito, Shuhei, Ohara, Susumu, and Adachi, Eijiro

Subjects
BIOREACTORS, ELECTRON microscopy, FIBROBLASTS, DERMIS, METALLOPROTEINASES, ENZYME inhibitors, TRANSPLANTATION of organs, tissues, etc.
Abstract

Dense connective tissues were generated simultaneously by accumulating collagen fibrils and fibroblasts on stainless steel mesh using a bioreactor system that we designed. The advantage of our system is that the artificial connective tissues can be generated within 24 hr in the absence of inhibitors against matrix metalloproteinases. The fibroblasts were suspended in 200 mL of Dulbecco's modified Eagle's medium containing 10%% fetal bovine serum and 0.5 mg//mL type I collagen. The mixed solution was circulated in two types of bioreactors with cylindrical or vertical configurations to generate luminal or parenchymal tissues, respectively. The gelatin zymography showed that MMPs were first detected in the media after 8 hr from the start of circulation and reached the highest levels on day 3. Glossy white aggregates, 1--3 mm in thickness, depending on the circulation period, accumulated on mesh grids. Fibroblasts were embedded in the network of collagen fibrils and possessed oval nuclei with or without prominent cell processes to form a bipolar shape. We could not observe distended cisternae of the endoplasmic reticula, the Golgi apparatus, or exploded mitochondria, showing hypoxic degenerative alterations of fibroblasts in dense connective tissues. The artificial tissues generated by our system will be useful for biological studies and transplantation therapy. [ABSTRACT FROM AUTHOR]

Published
2011
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36. Augmentative effects of L-cysteine and methylmethionine sulfonium chloride on mucin secretion in rabbit gastric mucous cells.

Author

Fujita, T, Watanabe, Tomoe, Ohara, Susumu, Miyazawa, Shitirou, Saigenji, Katunori, and Hotta, Kyoko

Subjects
MUCINS, GASTRIC mucosa, LABORATORY rabbits, TRANSMISSION electron microscopes, ADENOSINE triphosphate, CYTOCHEMISTRY
Abstract

AbstractBackground: Our previous study showed that L-cysteine (Cys) and methylmethionine sulfonium chloride (MMSC) inhibited ethanol-induced gastric mucosal damage and increased the amount of surface mucin in rats. This study examined whether Cys and MMSC augmented mucin secretion and changed distribution of mucin vesicles ultrastructurally in mucous cells by using primary cultured mucous cells from rabbit glandular stomach. Changes in intracellular cyclic adenosine 3′,5′-monophosphate (cAMP) and in levels of cytosolic free Ca2+ were investigated by treatment with Cys and MMSC. Methods: Mucin content was measured by an enzyme-linked lectin assay. Transmission electron micrography was used to examine ultrastructural distribution of mucin granules. The amount of cAMP or levels of free Ca2+ were measured by enzyme immunoassay or by fura-2. 16,16-Dimethyl prostaglandin E2 (dmPGE2) or ATP was used as the positive control. Results: L-Cysteine and MMSC increased mucin secretion and decreased cellular mucin content. The same was noted for dmPGE2. Accelerated mucin granule movements toward the plasma membrane were shown by these agents. Intracellular cAMP increased with exposure to dmPGE2 for 20 min, while neither Cys nor MMSC increased cAMP. No increase in cytosolic free Ca2+ levels occurred after treatment with Cys or MMSC, but an increase was induced 10 s after the addition of ATP. Conclusions: The present findings indicate that the increase in mucin secretion by Cys and MMSC was not mediated through the cAMP or Ca2+ signal transduction pathway, but might occur through non-receptor-mediated mechanisms. [ABSTRACT FROM AUTHOR]

Published
2000
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