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Biomedical subjects

Miho Sakai

Publications and source records attributed to Miho Sakai.

7 recordsLinked to original sources
PubMed2004

Quantitative assessment of tracheal collapsibility in infants with tracheomalacia.

Infantile tracheomalacia is a potentially life-threatening disease requiring prolonged artificial respiratory support. Diagnosis and management of this disease may be further improved by establishing a suitable objective and quantitative assessment protocol for tracheal collapsibility. It is our hypothesis that tracheal collapsibility can be represented by the relationship between intraluminal pressure and the cross-sectional area of the trachea. To test this hypothesis, static pressure/area relationships of the trachea were obtained from anesthetized and paralyzed infants, who were diagnosed as having tracheomalacia by endoscopic observation. These relationships were fitted on a linear regression model, followed by calculation of the estimated closing pressure. The tracheal closing pressure ranged from -8 to -27 cm H(2)O, suggesting easy collapsibility of the trachea during crying or coughing and noncollapsibility during the spontaneous respiratory cycle, which coincided with the infants' symptoms. It is our conclusion that tracheal collapsibility of infants with tracheomalacia can be quantitatively assessed by the static pressure/area relationship of the trachea obtained under general anesthesia and paralysis.

Airway Resistance↗
PubMed2003

Expression of novel rice gibberellin 2-oxidase gene is under homeostatic regulation by biologically active gibberellins.

We have cloned two genes for gibberellin (GA) 2-oxidase from rice ( Oryza sativa L.). Expression of OsGA2ox2 was not observed. The other gene, OsGA2ox3, was expressed in every tissue examined and was enhanced by the application of biologically active GA. Recombinant OsGA2ox3 protein catalyzed the metabolism of GA(1) to GA(8) and GA(20) to GA(29)-catabolite. These results indicate that OsGA2ox3 is involved in the homeostatic regulation of the endogenous level of biologically active GA in rice.

Amino Acid Sequence↗
PubMed2002

Single-step transformation for generating marker-free transgenic rice using the ipt-type MAT vector system.

The ipt-type MAT vector uses the ipt gene for regeneration of marker-free transgenic plants. However, it was pointed out that this system was not suitable for most economically important crops that regenerated through auxin-dependent embryogenesis. We report a single-step transformation system of rice using MAT vector. When we transformed scutellum tissues of 5 days pre-cultured rice seeds, marker-free transgenic rice plants directly regenerated from 25.5% infected scutellum tissues without forming ipt-intermediates within 4 weeks after an infection. Excision of the ipt gene caused the regeneration of marker-free transgenic rice plants through embryogenic tissues. Therefore, this system needs no selective agent and no sexual crossing for identification of transgenic plants not containing a selectable marker gene. This system is highly effective for generation of marker-free transgenic plants in economically important crops.

Alkyl and Aryl Transferases↗