FAS and periventricular leukomalacia: Flow cytometric analysis of primary myeloid and epithelial cells isolated from SO- and PVL-treated mice represented a similar condition (41.8% of the primary myeloid cells were FasL-positive in PVL-treated mice, while 27.6% of the primary epithelial cells were Fas-positive in PVL-treated mice) (Fig. 5d).