Browsing by Subject "Pineal"

Now showing 1 - 5 of 5
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    Age-related morphometric changes in the pineal gland. A comparative study between C57BLI6J and CBA mice
    (Murcia : F. Hernández, 2000) Cernuda-Cernuda, R.; Huerta, J.J.; Muñoz Llamosas, M.; Alvarez-Uría, M.; García-Fernández, J.M.
    Relatively little is known about the effects of melatonin on the aging of the pineal, the organ which is the main place for synthesis of this hormone. Using simple morphometric methods, some parameters of the pineal gland, such as total volume, number of pinealocytes and pinealocyte volume were estimated in two mice strains: normal CBA and melatonin-deficient C57BLl6J. Two age groups, 6 weeks and 10 months, were studied in order to evaluate possible differential age-related changes between both strains. Pineals of both strains have similar morphometric and morphological features at 6 weeks of age. This suggests that pineal development, which has already concluded at 6 weeks of age, is not affected by the absence of melatonin synthesis in the pinealocytes. Later on, CBA pineal showed an increase in size caused by cellular hypertrophy. In contrast, the C57BLl6J pineal volume decreased by loss of pinealocytes in the same period of time. Semithin sections analysed by light microscopy did not show that this cell death was evident in the C57BL16J strain at any of the ages studied. Thus, a gradual loss of pinealocytes could be hypothesised in these pineals. These results suggest that pineal melatonin could have a role in the maintenance of pinealocyte viability and the increase of pineal size which takes place after development. The abnormal pattern observed in the C57BL16J pineal should be taken into account in future studies on this gland.
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    Cell populations in the pineal gland of the viscacha (Lagostomus maximus). Seasonal variations
    (Murcia : F. Hernández, 2003) Cernuda-Cernuda, R.; Piezzi, R.S.; Domínguez, S.; Alvarez-Uría, M.
    Pineal samples of the viscacha, which were taken in winter and in summer, were analysed using both light and electron microscopy. The differences found between the two seasons were few in number but significant. The parenchyma showed two main cell populations. Type I cells occupied the largest volume of the pineal and showed the characteristics of typical pinealocytes. Many processes, some of which were filled with vesicles, could be seen in intimate contact with the neighbouring cells. The presence in the winter samples of “synaptic” ribbons and spherules, which were almost absent in the summer pineals, suggests a seasonal rhythm. These synaptic-like structures, as well as the abundant subsurface cisterns present in type I cells, appeared as basic differential features which allowed these cells to be distinguished from type II cells. These latter cells, which can be classified as interstitial cells, showed some other distinguishing features, such as irregular-shaped nuclei, abundant deposits of glycogenlike particles and structures of unknown function consisting of concentric cisterns surrounding a dense body. In the summer, interstitial cells displayed numerous large round bodies, which contributed to increase the cellular volume slightly. Regarding other constituents, like glial cell processes, vessels of nonfenestrated endothelium and sympathetic innervation, no qualitative differences were observed between the two seasons studied. We have presented here some morphological evidences of the circannual rhythm of the viscacha pineal, as well as ultrastructural criteria for distinguishing the main cell populations of this organ, which could be useful for studies carried out in other mammals.
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    Correlative study of squash smear cytology with histopathology in a rare case of anaplastic giant cell ependymoma of the pineal
    (2014) Toscano, Marzia; Butorano, Aimée Gloria Munezero; Cerase, Alfonso; Miracco, Clelia
    Anaplastic giant cell ependymoma (AGCE) is a very rare neoplasm. Its cytological features, helpful for the intraoperative diagnosis, have been reported only once. AGCE is characterized by giant cells with intranuclear inclusions, besides other findings, observable in ependymal neoplasms, such as intracytoplasmic vacuoles, epithelial and glial features of the tumor cells and ependymal pseudorosettes. These findings can be detected also in intraoperative squash smear. Herein we describe a pineal AGCE, highlighting the cytological and histological correlations and underlining some useful diagnostic clues of this unusual entity.
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    Melatonin and cancer: a polyhedral network where the source matters
    (MDPI, 2021-02-01) Tomas-Loba, Antonia; Bonmatí Carrión, María de los Ángeles; Anatomía Humana y Psicobiología
    Melatonin is one of the most phylogenetically conserved signals in biology. Although its original function was probably related to its antioxidant capacity, this indoleamine has been “adopted” by multicellular organisms as the “darkness signal” when secreted in a circadian manner and is acutely suppressed by light at night by the pineal gland. However, melatonin is also produced by other tissues, which constitute its extrapineal sources. Apart from its undisputed chronobiotic function, melatonin exerts antioxidant, immunomodulatory, pro-apoptotic, antiproliferative, and anti-angiogenic effects, with all these properties making it a powerful antitumor agent. Indeed, this activity has been demonstrated to be mediated by interfering with various cancer hallmarks, and different epidemiological studies have also linked light at night (melatonin suppression) with a higher incidence of different types of cancer. In 2007, the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption, where melatonin plays a central role. Our aim is to review, from a global perspective, the role of melatonin both from pineal and extrapineal origin, as well as their possible interplay, as an intrinsic factor in the incidence, development, and progression of cancer. Particular emphasis will be placed not only on those mechanisms related to melatonin’s antioxidant nature but also on the recently described novel roles of melatonin in microbiota and epigenetic regulation.
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    Postnatal neurogenesis in the cow pineal gland: an immunohistochemical study
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Gómez Esteban, M.B.; Muñoz Mosqueira, Mª.I.; Arroyo, A.A.; Muñoz Barragán, L.
    In the pineal gland of cows and rats structures designated rosettes have been described both during embryonic development and in adult animals. In order to investigate the possible nature of the cells comprising such structures, in the present work we studied the pineal glands from 10 cows of one- or fouryears-old using conventional immunocytochemical and confocal microscopy techniques. As markers of glial cells, we used anti-vimentin (Vim) and glial fibrillary acidic protein (GFAP) and anti-S-100 sera, and the pinealocytes were labelled with ß-III tubulin. As a marker of stem cells, we used an antinestin serum, while an anti-PCNA serum was employed to label proliferating cells. To explore the neuronal nature of some cells of the rosettes, we used an anti-SRIF serum. The rosettes were seen to be present throughout the glandular parenchyma and displayed a central cavity surrounded by cells, most of which expressed all or just some of the above glial labels and nestin, although there were also some rosettes with cells that expressed ß-III tubulin and other cells that expressed SRIF. Likewise, in the cells of the rosettes the cell nucleus showed strong expression of PCNA. Confocal microscopy revealed that the walls of the rosettes contained cells that coexpressed Vim/S-100, Vim/GFAP and Vim/nestin. The number of rosettes was significantly greater in the animals of one year of age with respect to the four-year-old cows. The present findings allow us to suggest that rosettes are evolving structures and that most of the cells present in their walls should be considered stem cells, and hence responsible for the postnatal neurogenesis occurring in the pineal gland of cows.