Abnormal Development and Apoptosis Observed in Brains of the Trisomy 16 Mouse

We have studied morphologic characteristics and apoptosis on the fetal brain of the trisomy 16 mouse, a model for human trisomy 21 syndrome. This study was based on serial sections of the whole brain from a sample of sixteen trisomy 16 mice and forty-six age-matched control littermates from embryonic day (ED) 12 to ED 18. Trisomy 16 brains showed a reduction of telencephalic size and abnormal cortical development. At ED 13 trisomy 16 and control brains appeared similar. By ED 14 difference in the cortical thickness and telencephalic growth became evident, and by ED 16 a marked size difference had developed between the trisomy 16 and control brains. By ED 18, however, the thickness of the trisomy 16 cortex had increased considerably and was not significantly different with respect to the thickness and cross-sectional areas of the pallium and its constituent cortical layers. The cell density of the trisomy 16 cortex had persistently decreased before ED 17, when the cell density of control and trisomy 16 corteces was similar within each layer. At ED 18 cell density of trisomy 16 cortex in each layer increased. There was inverse relationship between a number of TUNEL positive apoptotic cells and cell density in the trisomy 16 brains. Our results suggest that developmental abnormalities of the trisomy 16 brain indicated developmental delay of the telencephalon growth, which may be caused by apoptosis rather than by a proliferation defect.

Primitive Neuroectodermal Tumor of the Kidney: A case report

Peripheral primitive neuroectodermal tumor (pPNET), a rare, highly aggressive neoplasm of indetermined histogenesis, occurs typically in the soft tissues of the chest wall and the paraspinal region. Comprehensive diagnostic studies including histological, ultrastructural, immunohistochemical and molecular analyses have been stressed to diagnose this entity. We report a case of primary renal PNET which was incidentally found in a 59-year-old man who presented with generalized weakness for 4 months. He was diagnosed as a non-insulin dependent diabetes mellitus 15 years ago and has been made well by oral therapy. An ill-defined mass, measuring 3.5 3 cm, located in the left kidney and perirenal fat, was incidentally found by ultrasonogram during a renal diabetic examination. The mass was resected because of the unresponsiveness against one-year chemotherapy and radiation therapy. Grossly, a homogeneously solid, gray-white mass, measuring 2.8 1.8 cm, was noted in the mid portion of renal cortex. The mass showed severe adhesion to the perirenal fatty tissue. Microscopically, tumor cells were rather uniform, small round with scanty cytoplasm and often showed rosette formation. Ultrastructurally, they showed membrane-bound dense core granules, measuring 125~150 nm, intercellular junctions and microvillous cytoplasmic projections. The tumor cells were uniformly immunoreactive for neuron-specific enolase and were focally immunoreactive for CD99 (013), chromogranin, synaptophysin and cytokeratin. They were not reactive for S-100 protein, vimentin, Leu-7, leukocyte common antigen, desmin and smooth muscle actin. To our knowledge, this is the smallest renal PNET in literature.