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Oligodendrogliomas are an important adult form of diffuse gliomas with a distinctive clinical and genetic profile. Histologically similar tumors occurring rarely in children are incompletely characterized. We studied 50 patients with oligodendrogliomas (median age at diagnosis 8 y, range 7 mo to 20 y). Tumors resembling dysembryoplastic neuroepithelial tumors or pilocytic astrocytomas or those having a "mixed" histology were excluded. Tumors at first diagnosis were low grade (n=38) or anaplastic (n=12). Histologic features included uniform round cells with perinuclear halos (100%), secondary structures (predominantly perineuronal satellitosis) (90%), calcifications (46%), and microcysts (44%). Sequential surgical specimens were obtained in 8 low-grade oligodendroglioma patients, with only 1 progressing to anaplasia. Studies for 1p19q performed in 40 cases demonstrated intact 1p19q loci in 29 (73%), 1p19q codeletion in 10 (25%), and 1p deletion with intact 19q in 1 (2%). Except for 2 young patients (3 and 11 y of age), patients with 1p19q codeletion were older than 16 years at diagnosis. Mutant IDH1 (R132H) protein immunohistochemistry was positive in 4 (of 22) (18%) cases, 3 of which also had 1p19q codeletion, whereas 1p19q status was not available on the fourth case. There was a nonsignificant trend for worse overall survival in grade III tumors, but no significant association with age, extent of resection, or 1p19q status. In summary, oligodendrogliomas with classic histology occur in the pediatric population but lack 1p19q codeletion and IDH1 (R132H) mutations in most instances. They are predominantly low grade, recur/clinically progress in a subset, but demonstrate a relatively low frequency of histologic progression.

Purpose: Renal stone formation requires the persistent retention of crystals in the kidney. Calcium oxalate monohydrate (COM) crystal binding to Madin Darby canine kidney strain I (MDCK-I), a cell line that resembles the epithelium in the renal distal tubule/collecting duct, is developmentally regulated, while LLC-PK1 cells (American Type Tissue Collection), which are widely used as a model of the renal proximal tubule, bind crystals irrespective of their stage of epithelial development. Whereas to our knowledge the binding molecules for COM at the surface of LLC-PK1 cells are still unknown, crystals adhere to the hyaluronan (HA) rich pericellular matrix transiently expressed by mobile MDCK-I cells. In the current study we investigated whether crystal binding to either cell type is influenced by urinary substances, including glycoprotein inhibitors of crystallizationMaterials and Methods: We studied crystal binding to MDCK-I cells during wound repair, to confluent LLC-PK1 cells and to HA immobilized on a ...

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