Multiple subpial transections: the Yale experience.

PURPOSE: Although resection of an epileptogenic region is the mainstay of epilepsy surgery, epileptogenic areas in functionally critical cortex cannot be approached in that manner. Multiple subpial transection (MST) was developed to treat those refractory seizures without causing unacceptable neurologic deficit. We review our experience with this technique. METHODS: Twelve patients who underwent MST with or without resection between 1990 and 1998 were retrospectively reviewed with regard to seizure and neurologic outcome, and predictive factors. RESULTS: Five (42%) of 12 patients obtained a significant improvement in seizure frequency, and two other patients had a marked decrease in the severity of their seizures. Resection with MST reduced seizure frequency more, but this was not a significant difference. No predictive factors for outcome were identified. Only one patient sustained any persistent neurologic deficit. CONCLUSIONS: In selected patients, MST may be a viable alternative when the epileptogenic focus lies in unresectable cortex. A multicenter study with appreciable patient numbers will be necessary to define predictive factors for success.

Protease nexin-1 activity in cultured Schwann cells.

We report that protease nexin-1 (PN-1), a serine protease inhibitor known to have neurite-promoting effects, is made by Schwann cells in tissue culture. Three modalities have been used to demonstrate the presence of PN-1 in Schwann cell cultures. Immunostaining of the cultures with anti-PN-1 antibody gives positive staining over cells and matrix. Western blots of Schwann cell conditioned medium (CM) using anti-PN-1 antibody show a band that co-migrates with the PN-1 standard at 45 kDa. Biochemical assay for protease inhibitory activity shows that CM inhibits thrombin activity in a calorimetric assay. The CM-mediated inhibition of thrombin is reversed if the CM is pre-incubated with anti-PN-1 antibody.