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Biomedical subjects

Ken-ichi Hirasawa

Publications and source records attributed to Ken-ichi Hirasawa.

2 recordsLinked to original sources

Reversible restricted diffusion of entire corpus callosum.

MR imaging of a 31-year-old man with bacterial meningo-encephalitis associated with infectious endocarditis demonstrated T2 prolongation and restricted diffusion involving the entire corpus callosum and symmetrically involving the cerebral hemispheric white matter. His neurological signs and symptoms were mild, and recovery was complete within a week. Follow-up MR imaging with a 9-day interval revealed complete resolution of these lesions. The clinical and radiological courses were identical to those previously reported with a reversible lesion isolated to the splenium, or to the splenium and peripheral fronto-parietal white matter. This suggests that such reversible lesions are not necessarily restricted to the splenium, but may involve the entire corpus callosum.

Adult↗

Effects of scavengers for active oxygen species on cell death by cryptogein.

The hypersensitive reaction is a type of programmed cell death in plants. Cryptogein is a proteinaceous elicitor secreted from Phythophthora cryptogea. In one current model, active oxygen species (AOS) trigger programmed cell death in plants. In this study, we examined a variety of AOS scavengers to elucidate the function of AOS in the death program. Most of these AOS scavengers, including tiron, a scavenger for superoxide radical, catalase for hydrogen peroxide, and hydroquinone, sodium ascorbate and propyl gallate for free radicals, almost completely removed extracellular AOS. However, none of the reagents completely blocked the cell death process. Other reagents, such as histidine and dimethylfuran, scavengers for singlet oxygen, and diphenyleneiodonium chloride, an inhibitor of NADPH oxidase, showed significant toxicity in BY-2 cells. These results indicate that AOS produced in the extracellular space do not play a role in hypersensitive cell death.

Algal Proteins↗