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722 results on '"SEKIZAWA, KIYOHISA"'

10. Erythromycin increases bactericidal activity of surface liquid in human airway epithelial cells

Author

Ishizawa, Kota, Suzuki, Tomoko, Yamaya, Mutsuo, Jia, Yu Xia, Kobayashi, Seiichi, Ida, Shiro, Kubo, Hiroshi, Sekizawa, Kiyohisa, and Sasaki, Hidetada

Subjects
Epithelial cells -- Research, Erythromycin -- Research, Biological sciences
Abstract

Macrolide antibiotics have clinical benefits in patients with diffuse panbronchiolitis and in patients with cystic fibrosis. Although many mechanisms have been proposed, the precise mechanisms are still uncertain. We examined the effects of erythromycin on bactericidal activity of airway surface liquid secreted by cultured human tracheal epithelial cells. Airway surface liquid was collected by washing the surface of human tracheal epithelial cells with a sodium solution (40 meq/l). Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa were incubated with airway surface liquid, and the number of surviving bacteria was examined. The number of bacteria in airway surface liquid from the cells cultured in medium alone was significantly lower than that in the sodium solution. Furthermore, the number of bacteria in airway surface liquid from the cells treated with erythromycin was significantly lower than that in airway surface liquid from the cells treated with solvent alone. The production of mRNA and protein of human [beta]-defensin-1 and human [beta]-defensin-2 was significantly increased by erythromycin. Bactericidal activity of airway surface liquid was observed at low concentrations (40 meq/1) of sodium but not at higher concentrations ([greater than or equal to] 80 meq/l). Airway surface liquid did not contain significant amounts of antibiotics supplemented in the culture medium. Erythromycin at the levels in airway surface liquid and in culture medium did not inhibit bacterial growth. These results suggest that erythromycin may increase bactericidal activity of airway surface liquid in human airway epithelial cells through human [beta]-defensins production and reduce susceptibility of the airway to bacterial infection. defensin; airway surface liquid

Published
2005

22. Dopamine D1 receptor antagonist inhibits swallowing reflex in guinea pigs

Author

Jia, Yu Xia, Sekizawa, Kiyohisa, Ohrui, Takashi, Nakayama, Katsutoshi, and Sasaki, Hidetada

Subjects
Dopamine receptors -- Physiological aspects, Deglutition -- Physiological aspects, Guinea pigs -- Physiological aspects, Substance P -- Physiological aspects, Biological sciences
Abstract

Research was conducted to test whether dopamine D1 receptor antagonist influences the swallowing reflex and reduces substance P in the peripheral organs of guinea pigs. A catether was inserted through the mouth of the pigs so that the tip of the catheter lays in the pharynx. The animals were treated with subcutaneous injections of a selective dopamine D1 receptor antagonist. Results suggested that inhibition of the dopamine D1 receptor may impair the swallowing reflex and reduce substance P content in the peripheral organs.

Published
1998

28. Rhinovirus infection of primary cultures of human tracheal epithelium: role of ICAM-1 and IL-1Beta

Author

Terjima, Masanori, Yamaya, Matsuo, Sekizawa, Kiyohisa, Okinaga, Shoji, Suzuki, Tomoko, Yamada, Norihiro, Nakayama, Katsutoshi, Ohrui, Takashi, Oshima, Takeko, Numazaki, Yoshio, and Sasaki, Hidetada

Subjects
Rhinoviruses -- Research, Tracheitis -- Research, Epithelial cells -- Research, Virus diseases -- Research, Biological sciences
Abstract

Primary cultures of human tracheal epithelial cells were infected with human rhinovirus (HRV)-2 and HRV-14 to examine how rhinovirus infection influence respiratory epithelium. Viral titers of of supernatants and intracellular adhesion molecule-1 mRNA were reduced by a interleukin-1Beta neutralizing antibody. Results offer insights on airway inflammation caused by asthma-related viral infections.

Published
1997

36. P(sub 2u)-purinoceptor regulation of chloride secretion in cultured human tracheal submucosal glands

Author

Yamaya, Mutsuo, Sekizawa, Kiyohisa, Kakuta, Yasunori, Ohrui, Takashi, Sawai, Takashi, and Sasaki, Hidetada

Subjects
Purines -- Physiological aspects, Chlorides in the body -- Analysis, Respiratory mucosa -- Physiological aspects, Biological sciences
Abstract

Extracellular nucleotides evoke chloride secretion in cultured human tracheal submucosal glands through a P(sub 2u)-purinoceptor. This secretion is dependent on Ca2+ increase and activation of calcium-dependent potassium channels. Adenosine, AMP, ADP, ATP and uridine 5'-triphosphate evoke transient concentration-dependent short-circuit responses. These responses are suppressed by diphenylamine-2-carboxylic acid, quinidine and diisothiocyano-2,2'-stilbene disulfonate. Extracellular nucleotides increase Ca2+ intake. Ca2+'s rank order responses were similar to the short-circuit current responses.

Published
1996

42. Viral respriratory infection increases alveolar macrophage cytoplasmic motility in rats: role of NO

Author

Fukushima, Takeyasu, Sekizawa, Kiyohisa, Yamaha, Mutsuo, Okinaga, Sohji, Satoh, Masaru, and Sasaki, Hidetada

Subjects
Viral pneumonia -- Research, Cell membranes -- Research, Biological sciences
Abstract

The movement of organelles in alveolar macrophages (AM) in intact rats is investigated using ingested ferrimagnetic particles. The movement is predominant during viral respiratory infection by parainfluenza virus. The investigation reveals that the nitric oxide is involved in the AM cytoplasmic motility during the viral infection.

Published
1995

43. Oxidants affect permeability and repair of the cultured human tracheal epithelium

Author

Yamaya, Mutsuo, Sekizawa, Kiyohisa, Masuda, Tohru, Morikawa, Masatoshi, Sawai, Takashi, and Sasaki, Hidetada

Subjects
Airway (Medicine) -- Research, Epithelial cells -- Physiological aspects, Oxidizing agents -- Physiological aspects, Biological sciences
Abstract

A study of the influence of oxidants on the barrier functions of airway epithelium in human tracheal epithelial cells grown on porous filter membrane reveals that tracheal epithelial cell barrier function attenuation by oxidants occurs through tight junction damage and cell proliferation inhibition. H2O2 mediates the oxidant effects on epithelial cells. Ussing's chamber measurements reveal that xanthine plus xanthine oxidase, H2O2 and glucose oxidase enhance short-circuit current, electrical conductance across the membrane and mannitol flux through the epithelium.

Published
1995

45. Sputum E-cadherin and asthma severity

Author

Masuyama, Kuniko, Morishima, Yuko, Ishii, Yukio, Nomura, Akihiro, Sakamoto, Tohru, Kimura, Toru, Mochizuki, Mie, Uchida, Yoshiyuki, and Sekizawa, Kiyohisa

Published
2003

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