[Psychotic picture of long duration and tumors of the posterior cranial fossa (medulloblastoma of the vermis)].
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The authors describe the magnetic resonance (MR) findings in seven patients who developed severe cerebellar symptoms and atrophy of the contralateral red nucleus following removal of unilateral neoplasms in the deep nuclei of the cerebellum. For most patients, pre- and postoperative spin-echo MR images were obtained with long repetition times (TRs) at 1.5 T. The long TR images obtained before surgery demonstrated unilateral masses involving the dentate nucleus. Long TR images obtained after surgical resection of the dentate nucleus showed increased signal intensity in all of seven contralateral red nuclei, three of seven ipsilateral superior cerebellar peduncles, and two of seven contralateral inferior olivary nuclei. Three other patients who underwent surgery for cerebellar neoplasms without resection of the dentate nuclei showed no postoperative brain stem changes on MR images. The authors speculate that the changes in the contralateral red nuclei are due to cerebellorubral degeneration (since well-described neural tracts interconnect the dentate nucleus and the contralateral red nucleus). Injury of the dentate nucleus may result in degeneration of distant neural connections.
Medulloblastoma represents greater than 25% of childhood intracranial neoplasms and is considered a highly malignant tumor. This tumor, which arises predominantly in the cerebellar vermis, preferentially affects children between the ages of 5 and 15. Although the etiology of medulloblastomas in humans remains unknown, results from several experiments have indicated that the human neurotropic JC virus (JCV) is able to induce cerebellar neoplasms in rodents that exhibit a phenotype similar to that of human medulloblastomas. JCV is a polyomavirus that is widespread in the human population, with infection occurring most frequently in early childhood. In this study, we have examined the possible association of JCV with human medulloblastomas. By using PCR techniques we demonstrate that 11 of 23 samples of tumor tissue contain DNA sequences corresponding to three different regions of the JCV genome. More importantly, we demonstrate the presence of DNA sequences encoding the N- and C-terminal regions of the JCV oncogenic protein, T antigen, in 11 of 23 samples and the production of T antigen in the nuclei of 4 samples of tumor tissue. These observations provide evidence for a possible association of JCV with human medulloblastomas.
Fowl glioma-inducing virus (FGV), which belongs to subgroup A of avian leukosis virus (ALV), shows tumorigenicity and pathogenicity, mainly in the nervous system, and causes astrocytoma and perineurioma. Apart from these neoplasms, cerebellar anomaly was found in chickens infected with FGV in ovo. The study reported here describes the morphologic characteristics of the affected cerebellum. Specific-pathogen-free chickens (C/O) were inoculated with FGV through the yolk sac on the 7th day of incubation. The cerebellar anomaly included diffuse depletion of granular cells of the internal granular layer (IGL), remnants of the external granular layer (EGL), and disorganization of the Purkinje cell layer. These cerebellar changes were observed in all birds except one. In the infected embryos, the EGL was thicker and had an irregular arrangement with a thin molecular layer (ML) and IGL, compared with the control. The granular cells were immunohistochemically positive for ALV common antigen. Immunohistochemical analysis for vimentin revealed disarrangement and decreased number of Bergmann's fibers. Use of the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method and electron microscopy indicated that apoptotic granular cells were frequently observed in the EGL and ML. These results suggested that the cerebellar anomaly was hypoplasia, principally resulting from the apoptosis of granular cells in the EGL and ML caused by FGV infection and that the cell loss induced obstruction of granular cell migration and disarrangement of Bergmann's fibers in the ML.
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As a general trend, the diagnosis in medical clinics often depends on laboratory test results. Neurotological diagnosis, however, requires detailed neurological examinations on a patient by a neurotologist. Therefore, there are differing diagnostic skills among physicians, and there is a kind of "man-made flavor" in neurotological diagnostic procedure. In the present study, current development in the knowledge on the clinical diagnostic significance of pathological eye movement during the last 2-3 years is summarized. Acquired pendular wondering eye-movement. Fixation jerks. Spontaneous and transitory eyeball burst or seizure. Vertical rebound nystagmus. Optokinetic vertical ocular dysmetria. Divergence nystagmus. Counterolling, pure rotatory positioning nystagmus. Inversion of optokinetic after-nystagmus (OKAN). Vertical congenital nystagmus and inversion of optokinetic nystagmus (OKN). Treatment of congenital nystagmus. Vertical spontaneous nystagmus to lower eyelid or so-called "downbeat nystagmus." Downbeat nystagmus seen in bilateral labyrinthine dysfunction. The significance of bilateral vestibular lesion, or symmetric lesion in other is emphasized in the present report for reader's reference and criticism. Our experience on the clinical significance of the abnormal eye movement was reported. It is our wish that accumulation of data on important cases along with the results of experimental studies directly connected with clinical medicine may contribute to the progress of our neurotology in the right direction as "neurology of the posterior fossa."
The use of CSF polyamine levels for the detection of brain tumors is discussed, with special emphasis on the use of CSF polyamine levels for the diagnosis and care of patients with medulloblastoma.
If acute onset of esotropia is comitant, its cause is generally believed to be benign. Although this is, by and large, true, it is now clear that acute comitant esotropia may be associated infrequently with central nervous system illness. We describe six children who presented with acute onset of comitant esotropia, and who were found to have tumors of the brain stem or cerebellum. Four of the patients underwent strabismus surgery after appropriate neurologic and neurosurgical treatment was completed. In none of these patients was ocular motor fusion reestablished.
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While several genetic alterations associated with the evolution of the astrocytomas have been identified, the molecular basis of non-astrocytic brain tumors has remained largely unknown. In this study, p15, p16, CDK4 and cyclin D1 genes were analyzed in 69 nonastrocytic human brain tumors, including 17 oligodendrogliomas, 16 medulloblastomas/primitive neuroectodermal tumors (PNETs), 14 ependymomas and 22 meningiomas. Southern blot analysis of DNA from frozen samples showed no homozygous deletions in p15 or p16 genes in any of these tumors. No mobility shift was found by PCR-single-strand conformation polymorphism (PCR-SSCP) analysis in exons 1 and 2 of the p15 gene and exons 1 and 2 of the p16 genes, except for one oligodendroglioma. Direct sequencing of DNA from this tumor showed a G --> A transition at nucleotide 436 (codon 140) in exon 2 of the p16 gene, which is a common polymorphism. Southern blot analyses revealed no amplification of CDK4 and cyclin D1 genes in any of the neoplasms analyzed. In contrast to astrocytic brain tumors, which show frequent loss of the p16 gene and amplification of the CDK4 gene, alteration of these genes appears to be rare in other neoplasms of the human nervous system.
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As the most frequent solid tumor occurring in childhood, brain tumors constitute an important segment of pediatric oncology. Neurologic manifestations may be deceptively mild and easily overlooked or misinterpreted, particularly in the very young, because of the remarkable resiliency of the immature central nervous system and the skull's ability to expand throughout the pre-adolescent years. The majority of childhood tumors produce increased intracranial pressure, usually the consequence of obstructive hydrocephalus. Specific neurologic deficits correspond to the tumor's location. The posterior fossa harbors two-thirds of childhood tumors, and each of the four common tumors in this location produces a characteristic syndrome. Supratentorial tumors occupy the cerebral hemisphere, the suprasellar area, and the pineal gland. Diagnostic studies have reached a state of great sophistication and precise anatomical localization. Surgery, either alone or with adjuvant radiotherapy, cures no more than one-third of all tumors; for the remainder, it has a diagnostic and palliative role. The introduction of operative microsurgery has advanced the art, particularly in the surgical treatment of craniopharyngiomas and pinealomas, but any significant improvement in the treatment of brain tumors as a group seems unlikely to be achieved by surgery alone.