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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 83 (1992), S. 308-314 
    ISSN: 1432-0533
    Keywords: Large T-antigen ; Transgenic mice ; Pineal cell tumors ; Pineal organ ; Primitive neuroectodermal tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adult transgenic mice expressing the large T-antigen of the Simian virus 40 (SV 40) under the control of the Moloney murine sarcoma virus (MSV) enhancer and the SV 40 promoter develop inheritable uniform midline brain neoplasms showing features of primitive neuroectodermal tumors. The origin and histogenesis of these tumors were investigated in the present study. The brain and pineal organ of fetal and young transgenic mice less than 3 months old displayed normal macroscopic and microscopic features. In 3.5-month-old animals, the pineal organ was considerably enlarged due to hyperplasia, finally leading to tumor formation. Immunocytochemical demonstration of large T-antigen showed that this oncoprotein was already expressed in the nuclei of certain cells in the pineal organ of fetuses (16 and 18 days old) and newborn animals, but was absent from all other parts of the brain. The immunocytochemical demonstration of S-antigen (arrestin), a highly characteristic marker for pinealocytes, was used for further characterization of the large T-antigenimmunoreactive cells. The fetal pineal organ did not contain immunoreactive S-antigen. This first occurred in certain pinealocytes of newborn mice. Double immunostaining revealed that in newborn and older transgenic mice the immunoreactive large T-antigen was exclusively found in nuclei of cells containing S-antigen immunoreaction in their cytoplasm. Thus, transformed pinealocytes appear as stem cells of the experimental tumors. The results of this study suggest that primitive neuroectodermal tumors and the normal tissue from which they originate share certain molecular and immunocytochemical features.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 15 (1993), S. 131-137 
    ISSN: 1279-8517
    Keywords: Sacroiliac joint ; Computed tomography ; Secondary ossification centres ; Os sacrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Des formations osseuses apparemment bilatérales, de formes et tailles différentes, localisées dans les parties antéro-supérieures et inférieures des articulations sacroiliaques, ont été observées sur les images de coupes axiales de la région pelvienne chez des patients jeunes. Aucune autre modification pathologique n'a été notée au niveau des articulations sacro-iliaques de ces individus. Chez l'un des patients, les structures osseuses pouvaient aussi être observées sur les radiographies standard. Nous avons aussi étudié cette articulation chez 3 sujets anatomiques juvéniles, par la radiographie, la TDM, l'étude macroscopique et histologique. Chez deux d'entre eux des formations osseuses semblables à celles observées chez les patients jeunes pouvaient être détectées sur les coupes TDM. Les recherches macroscopiques ont montré que ces structures étaient des points d'ossification secondaires localisés dans le cartilage articulaire de la partie latérale du sacrum en regard du 1er et du 3e segments sacrés. Si l'on se réfère à une littérature anatomique plus ancienne, ces points d'ossification épiphysaires contribuent à la surface auriculaire de la partie latérale du sacrum et à la surface libre latérale des parties caudales du sacrum. Ils peuvent être observés entre 12 et 25 ans et commencent à fusionner avec les parties latérales aux environs de la 18e année. Sur les bassins osseux provenant de pièces juvéniles conservées, les ossicules libres n'ont pas pu être décelés dans la région des articulations sacroiliaques. Les particularités histologiques du processus d'ossification observé sont discutés. Ces points d'ossification physiologiques doivent être distingués des altérations pathologiques apparaissant au scanner comme des structures osseuses ou assimilées.
    Notes: Summary Bilateral apparently bony structures of different forms and sizes located in the inferior and superior ventral parts of the sacroiliac joints were observed on axial CT images of the pelvic region of juvenile patients. No other pathological changes were noted in the sacroiliac joints of these individuals. In one patient the bony structures could also be seen on a conventional plain radiograph. We also examined 3 juvenile autopsy specimens of this joint using radiology, CT, macroscopical evaluation and histology. In two of them, structures could be detected on the CT scans which were similar to those observed in the young patients. Macroscopic investigations revealed the structures to be secondary ossification centres located in the articular cartilage of the lateral part of the os sacrum at the levels of the first and third sacral segments. According to older anatomical literature, these epiphysial ossification centres contribute to the auricular surface of the lateral part of the os sacrum and the free lateral surface of the inferior sacral parts. They can be observed between the ages of 12 and 25 years and begin to synostose with the lateral part around the age of 18 years. In macerated juvenile specimens of the bony pelvis, free ossicles were not detectable in the region of the sacroiliac joints. Histological peculiarities of the ossification process observed are discussed. These physiologically occurring ossification centres are to be differentiated from pathological alterations appearing as bony or bone-like structures on CT scans.
    Type of Medium: Electronic Resource
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