RESUMEN
Dysembryoplastic neuroepithelial tumor (DNET) is a benign mixed neuronal-glial neoplasm (WHO grade 1). DNET is most often localized in temporal lobes and found in children and young people with epilepsy. There a few cases of DNET in ventricular system with dissemination along the ependyma in the world literature. MATERIAL AND METHODS: We present a rare case of T1- and T2-negative ventricular system tumor. Only FIESTA imaging revealed dissemination with multiple focal lesions of the third ventricle, its bottom and lateral walls, anterior horns of lateral ventricles, cerebellar vermis, cervical and lumbar spinal cord. RESULTS: The patient underwent transcortical endoscopic biopsy of the third ventricle tumor with simultaneous ventriculoperitoneal shunting. DNET was diagnosed, and radiotherapy was subsequently performed. Literature data on this issue were analyzed. CONCLUSION: To date, disseminated forms of DNET are extremely rare. X-ray features and morphological results allow us to establish the correct diagnosis and determine further treatment strategy.
Asunto(s)
Neoplasias Neuroepiteliales , Humanos , Neoplasias del Ventrículo Cerebral/cirugía , Neoplasias del Ventrículo Cerebral/diagnóstico por imagen , Neoplasias del Ventrículo Cerebral/patología , Neoplasias del Ventrículo Cerebral/complicaciones , Neoplasias Neuroepiteliales/cirugía , Neoplasias Neuroepiteliales/diagnóstico por imagen , Neoplasias Neuroepiteliales/complicaciones , Neoplasias Neuroepiteliales/patologíaRESUMEN
The participation of the nerve termini growth associated protein GAP-43 in neurite outgrowth and targeting is well documented. Commonly, besides GAP-43 itself, two big fragments devoid of four (GAP-43-2, IB-50) and of about 40 (GAP-43-3, B-60) N-terminal residues were co-isolated from brain. In adult brain, GAP-43 significantly prevails over the fragments. To find their relative amounts during development, rat brain proteins were isolated on different stages of embryonal and post-natal development and subjected to gel electrophoresis in 0.9 M acetic acid-2.5 M urea system. The bands of GAP-43 protein family were detected on Western blots. We show that in developing brain (until 5th post-natal day), a proteolysis of GAP-43 near Ser(41) that results in GAP-43-3 accumulation is activated. We hypothesize that just the functions that can be performed by the GAP-43 fragments are of importance for developing brain.
Asunto(s)
Encéfalo/metabolismo , Proteína GAP-43/metabolismo , Animales , Animales Recién Nacidos , Encéfalo/embriología , Encéfalo/crecimiento & desarrollo , Femenino , Embarazo , Isoformas de Proteínas/metabolismo , Ratas , Ratas WistarRESUMEN
GAP-43 protein of nerve terminals (B-50, F1, F57, pp46, neuromodulin) is thought to be one of key proteins involved in the control of outgrowth of neurites, release of neuromediators, synapse plasticity, etc. GAP-43 is usually considered as a whole protein. Along with the intact protein, nerve cells also contain two large native fragments of GAP-43 deprived of four or of about forty N-terminal amino acid residues (GAP-43-2 and GAP-43-3, respectively). The full-length GAP-43 is predominant in the mature brain. However, the ratio of the full-length protein and its fragments can vary under different physiological conditions. Changes in the GAP-43 proteins (the full-length protein and its fragments) were studied during embryonal and postnatal development of rat brain. The GAP-43 proteins were found to be expressed not later than on the 12-13th day of embryogenesis. Then their contents increased, and, until the 10th day after birth, GAP-43-3 dominated rather than the full-length protein. It is suggested that during this period the activity of a specific protease, which cleaves the N-terminal peptide of about 40 residues from the full-length GAP-43 molecule, is increased. The cleavage occurs in the region responsible for the interaction of GAP-43 with calmodulin. In the full-length molecule, this region is responsible also for the recognition of Ser41 residue by protein kinase C during phosphorylation. Another functionally important region that determines, in particular, the attachment of GAP-43 to the plasma membrane is cleaved from the main part of the molecule together with the N-terminal peptide. Thus, the specific fragmentation of GAP-43 that depends on developmental stage should be considered as a controlled structural rearrangement fundamentally affecting the functions of this protein.