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Biomedical subjects

Y Segawa

Publications and source records attributed to Y Segawa.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Multi-layer amniotic membrane graft for pterygium in a patient with xeroderma pigmentosum.

BACKGROUND: Xeroderma pigmentosum (XP) is a rare, autosomal recessive, premalignant condition of the skin, and is reported to be associated with ocular surface disorders such as conjunctival malignancy and pterygium. Herein, we report a case of successful management of pterygium with multi-layer amniotic membrane graft (AMG) in a young XP patient. CASE: An 11-year-old Japanese girl, who had been diagnosed as having XP, was referred to us for treatment of her bilateral pterygium. Surgical intervention was attempted for a temporal, presumably fast-growing pterygium in her left eye. Multi-layer amniotic membrane grafting was performed. OBSERVATIONS: The surgery-induced pain and irritation disappeared within a day. The limbal conjunctival autograft survived on the AMG and re-epithelialization over the AMG was completed in 2 weeks. Best corrected visual acuity improved from 20/32 to 20/16 one month postoperatively. During the 1-year follow-up period, no recurrence was noted. CONCLUSIONS: The present case exemplifies that AMG as an adjunct to primary pterygium resection is effective even in a young patient with XP. In addition, multi-layer AMG, which we first demonstrated in this report, seems to be useful for protecting bare sclera and extraocular muscles from mechanical injury.

Amnion↗
PubMedDate not supplied

Retinal pigment epithelial origin of bicarbonate response.

The mechanisms of the bicarbonate-induced decrease in the ocular standing potential (bicarbonate response) were investigated in the cat. An intravenous infusion of 1.4% sodium bicarbonate solution caused a decrease in the standing potential. A high-bicarbonate solution decreased or increased the potential across the retinal pigment epithelium-choroid tissue of the excised cat eye when applied basally or apically, respectively, but did not affect the potential across the anterior portion of the excised eye or across the isolated neural retina. A high-bicarbonate solution principally depolarized the apical membrane of the retinal pigment epithelium (RPE) when applied basally, and hyperpolarized it when applied apically. These results suggest that the bicarbonate response in the cat is primarily due to the effects of an increase in bicarbonate concentration on the basal membrane of the RPE.

Animals↗