Rapamycin is a potent immunosuppressant with antitumoral properties widely used in the field of renal transplantation. To test the hypothesis that the antiproliferative and antiangiogenic activity of rapamycin interferes with the normal structure and function of growth plate and impairs longitudinal growth, 4-week-old male rats (n=10/ group) receiving 2 mg/kg per day of intraperitoneal rapamycin (RAPA) or vehicle (C) for 14 days were compared. Rapamycin markedly decreased bone longitudinal growth rate (94±3 vs. 182±3 μm/day), body weight gain (60.2±1.4 vs. 113.6±1.9 g), food intake (227.8±2.6 vs. 287.5±3.4 g), and food efficiency (0.26±0.00 vs. 0.40± 0.01 g/g). Signs of altered cartilage formation such as reduced chondrocyte proliferation (bromodeoxiuridine-labeled cells 32.9±1.4 vs. 45.2±1.1%), disturbed maturation and hypertrophy (height of terminal chondrocytes 26±0 vs. 29±0 μm), and decreased cartilage resorption (18.7±0.5 vs. 31.0±0.8 tartrate-resistant phosphatase alkaline reactive cells per 100 terminal chondrocytes), together with morphological evidence of altered vascular invasion, were seen in the growth plate of RAPA animals. This study indicates that rapamycin can severely impair body growth in fastgrowing rats and distort growth-plate structure and dynamics. These undesirable effects must be kept in mind when rapamycin is administered to children.

Zeins are the major storage proteins in maize (Zea mays) endosperm, and their accumulation in zein bodies derived from the endoplasmic reticulum is well characterized. In contrast, relatively little is known about post-Golgi compartments or the trafficking of vacuolar proteins in maize endosperm, specifically the presence of globulins in structures resembling protein storage vacuoles that appear in early to mid-stage seed development. We investigated this pathway by expressing and analyzing a recombinant reporter glycoprotein during endosperm maturation, using a combination of microscopy and sensitive glycopeptide analysis. Specific N-glycan acceptor sites on the protein were followed through the stages of grain development, revealing a shift from predominantly paucimannosidic vacuolar glycoforms to predominantly trimmed glycan structures lacking fucose. This was accompanied by a change in the main subcellular localization of the protein from large protein storage vacuole-like post-Golgi organelles to the endoplasmic reticulum and zein bodies. The endogenous storage proteins corn a-globulin and corn legumin-1 showed a similar spatiotemporal profile both in transgenic plants expressing the reporter glycoprotein and in wild-type plants. This indicates that the shift of the intracellular trafficking route, as observed with our reporter glycoprotein, may be a common strategy in maize seed development.

Growth depression is a side effect of high-dose glucocorticoid therapy in childhood. It is partially mediated by alterations of the somatotropic hormone axis and partially by direct local effects on growth plate chondrocytes. The mechanisms of interaction of corticosteroids and somatotropic and calciotropic hormones at the cellular level were recently investigated in more detail, using experimental models of primary cultures of growth plate chondrocytes. In proliferative chondrocytes, growth hormone (GH) and the calciotropic hormones parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1alpha,25(OH)2D3] increase cell proliferation via stimulation of paracrine insulin-like growth factor-I (IGF-I) secretion. Corticosteroids decreased GH, and PTH or 1alpha,25(OH)2D3 stimulated cell growth in a dose-dependent manner. Corticosteroids in high doses reduced the expression of the GH receptor and type 1 IGF receptor. But the main antiproliferative molecular effect of corticosteroid was the reduction in basal and hormone-stimulated IGF-I secretion. The in vitro results are in accordance with the observation in animal experiments and in children treated with corticosteroids, demonstrating that the growth-depressing effect of corticosteroids can be compensated for by supraphysiological doses of GH or IGF-I.

We report a case of spinal cord neurocytoma in a 67-year-old man who had experienced a progressive numbness of the left foot during the previous 4 years. Magnetic resonance imaging showed a well-defined intramedullary tumor located at the T10-T11 level. The pathological examination revealed histological characteristics described in neurocytomas. The tumor cells showed a uniform small nucleus and clear or slightly eosinophilic cytoplasm with frequent perinuclear halos, resembling the picture of oligodendroglioma. Some tumor cells exhibited mature ganglion cell appearance. Electron microscopy showed cells with microtubules and dense-core vesicles in their cytoplasm and cytoplasmic process. Immunohistochemically, the majority of tumor cells expressed synaptophysin and neuron-specific enolase. We conclude that this tumor is an exceptional case of neurocytoma located in the spinal cord, and consider that the term neurocytoma can be applied to tumors with neuronal differentiation intermediate between neuroblastoma and ganglioneuroma, even if arising in CNS outside of the intracranial ventricular system.