Photophobia in a blind eye after removal of a progressive orbital optic glioma with denervation.

UNLABELLED: Optic glioma (OPG) accounts for 4-8% of all brain tumors in children. En-block removal of intraorbital tumor is recommended in cases with disfiguring exophthalmos and impaired vision. Surgical resection of intraorbital optic nerve (ON) poses the risks of permanent ptosis and globe atrophy. We present here the case of a 4-year-old boy with exophthalmos and near blindness due to an intraorbital OPG. Despite chemotherapy he showed progressive exophthalmos and vision loss. Bony orbital decompression with ON transection temporally reduced his exophthalmos. OPG resection was required later for recurrence of his exophthalmos secondary to tumor progression. Post operatively, he had preserved oculomotor nerve functions but developed globe ischemia. Unusually, his ischemic globe caused him to have pain and severe photophobia, which later lead to enucleation. Photophobia has been reported in blind patients. Animal models and MRI functional imaging showed activation of trigeminal pathway during photophobia in completely transected ON. However, the exact neuro-ophthalmology pathway requires further study. CONCLUSION: This is the first described case of photophobia after excision of OPG with ON denervation. Photophobia can be a serious side effect that significantly lowers the patient's quality of life.

Lipoxygenase-catalyzed phospholipid peroxidation: preparation, purification, and characterization of phosphatidylinositol peroxides.

The importance of understanding the mechanisms of modulation of cellular signaling cascades by the peroxidized membrane phospholipids (PLs) is well recognized. The enzyme-catalyzed peroxidation of PLs, as opposed to their oxidation by air and metal catalysis, is well controlled and rapid and yields well-defined PL peroxides which are highly desirable for biological studies. Therefore, here, we chose bovine liver phosphatidylinositol (PI), a crucial membrane PL which acts as the substrate for phospholipase C in cellular signal transduction, as a model membrane PL. We successfully generated the PI peroxides with soybean type-I lipoxygenase (LOX) in the presence of deoxycholate, which facilitates the LOX-mediated peroxidation of the polyunsaturated fatty acids esterified to the PL. The LOX-peroxidized PI, after enzymatic catalysis, was separated from the unoxidized PI in the reaction mixture by normal-phase, high-performance liquid chromatography (HPLC). The extent of LOX-mediated peroxidation of PI following HPLC purification was established by the analysis of lipid phosphorus, conjugated dienes by UV spectrophotometry, peroxides, and loss of fatty acids by gas chromatography. This study established the optimal conditions yielding approximately 46% of peroxidized PI from 300 microg of neat bovine liver PI that was peroxidized by soybean type-I LOX (50 microg) for 30 min in borate buffer (0.2 M, pH 9.0) containing 10 mM deoxycholate.