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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A variety of studies on neuronal death models suggest that lithium has neuroprotective properties. In the present investigation, we have examined the effect of chronic lithium treatment on hippocampus, as monitored by changes at the subcellular level of apoptosis-regulatory proteins which have been induced by the neurotoxin, aluminum maltolate. Intracisternal administration of aluminum into rabbit brain induces cytochrome c release, decreases levels of the anti-apoptotic proteins Bcl-2 and Bcl-XL, increases levels of the pro-apoptotic Bax, activates caspase-3, and causes DNA fragmentation as measured by the TUNEL assay. Pretreatment for 14 days with 7 mm of lithium carbonate in drinking water prevents aluminum-induced translocation of cytochrome c, and up-regulates Bcl-2 and Bcl-XL, down-regulates Bax, abolishes caspase-3 activity and reduces DNA damage. The regulatory effect of lithium on the apoptosis-controlling proteins occurs in both the mitochondria and endoplasmic reticulum. We propose that the neuroprotective effect of lithium involves the modulation of apoptosis-regulatory proteins present in the subcellular organelles of rabbit brain.
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 33 (1979), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The effects of altered osmolality on respiration and fine structure were studied in isolated cerebral mitochondria from mature rats (60-100 days of age) and from rat pups in the first month of postnatal life (5, 10, 20 and 30 days). In the mature cerebral mitochondria, ADP-dependent respiration was inhibited in media of decreased osmolality. There was a transient inhibition of ADP-dependent respiration and a sustained increase in ADP-independent respiration in media of increased osmolality. In contrast, cerebral mitochondria from 5-day-old rats showed both inhibition of ADP-dependent respiration and increased ADP-independent respiration in hypo-osmolal media. In these mitochondria, inhibition of ADP-dependent respiration was stable and ADP-independent respiration was unchanged in media of increased osmolality. The transition to the mature respiratory response occurring with altered osmolality took place between 10 and 30 days of age. During this same age period, cerebral mitochondria showed an increasing resistance to matrix condensation in media of normal and increased osmolality.
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  • 3
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Neurotrophin-3 (NT-3) exerts its trophic effects in brain via tyrosine kinase receptor C (trkC) signaling. TrkC splice variants produce receptors with (full-length) and without (truncated) a tyrosine kinase domain. The relative abundance of trkC isoforms and the anatomical localization of trkC in the human prefrontal cortex (PFC) in relationship to development and maturation are currently unknown. We have examined the temporo-spatial expression of trkC protein and mRNA during the development of the human PFC. We have found two major isoforms, a full-length (150 kDa) and a truncated (50 kDa) form of the trkC protein in the human PFC. We report that the full-length form is expressed at low levels throughout development while the truncated form is expressed at moderate levels early in development and increases to reach mature levels by adolescence. In contrast, trkC mRNA levels are uniformly expressed throughout most of postnatal life, but decline in ageing. TrkC protein and mRNA are expressed in both pyramidal and non-pyramidal neurons; additionally, trkC protein is detected in glia and neuropil. Our results suggest that truncated trkC is prevalent in the human PFC and that neurons and glia may be responsive to NT-3 in the PFC throughout life.
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  • 4
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The N-methyl-d-aspartate receptor plays a critical role in the formation and maintenance of synapses during brain development. In the rodent, changes in subunit expression and assembly of the heteromeric receptor complex accompany these maturational processes. However, little is known about N-methyl-d-aspartate receptor subunit expression during human brain development. We used in situ hybridization to examine the distribution and relative abundance of NR1, NR2A and NR2B subunit messenger ribonucleic acids in the hippocampal formation and adjacent cortex of 34 human subjects at five stages of life (neonate, infant, adolescent, young adult and adult). At all ages, the three messenger ribonucleic acids were expressed in all subfields, predominantly by pyramidal neurons, granule cells and polymorphic hilar cells. However, their abundance varied across ontogeny. Levels of NR1 messenger ribonucleic acid in CA4, CA3 and CA2 subfields were significantly lower in the neonate than all other age groups. In the dentate gyrus, subiculum and parahippocampal gyrus, NR2B messenger ribonucleic acid levels were higher in the neonate than in older age groups. NR2A messenger ribonucleic acid levels remained constant, leading to an age-related increase in NR2A/2B transcript ratio. We conclude that N-methyl-d-aspartate receptor subunit messenger ribonucleic acids are differentially expressed during postnatal development of the human hippocampus, with a pattern similar but not identical to that seen in the rodent. Changes in subunit composition may thus contribute to maturational differences in human hippocampal N-methyl-d-aspartate receptor function, and to their role in the pathophysiology of schizophrenia and other neurodevelopmental disorders.
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  • 5
    ISSN: 1432-2307
    Keywords: Melanin ; Teratoma ; Tyrosinase ; Tyrosine hydroxylase ; Immunofluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A pigmented tumor fraction, designated IB-9, obtained following cellular dissociation and elutriation procedures applied to the solid transplants of the OTT-6050 mouse teratoma cell line, was characterized enzymatically and by immunofluorescence for the presence of tyrosinase and tyrosine hydroxylase (TH). Enzymatic assays of the pigmented tumors were compared with those obtained on non-pigmented teratoma-derived tumors, on pigmented tumors obtained from the mouse melanoma B16 line as a control for tyrosinase activity, and on whole brains of adult 129/J mice as a control for TH activity. All the teratoma-derived tumors, including the IB-9 fraction, showed a predominance of TH over tyrosinase activity. The levels of TH activity appeared independent of the presence or the extent of melanin pigment. All pigmented teratoma-derived tumors showed low levels of tyrosinase activity. On the basis of the enzymatic assays, the IB-9 tumors were divided into two groups: group I, which showed low enzyme activity, almost certainly entirely tyrosinase; and group II, in which the enzyme activity appeared largely due to TH, with presumably a very low background of tyrosinase activity. Immunofluorescence demonstrated the localization of TH activity to non-pigmented cells of the IB-9 fraction, whereas the pigmented cells showed absence of TH activity. These findings, taken in conjunction with the presence by electron microscopy of premelanosomes and melanosomes, indicate that pigment formation associated with melanosomal differentiation in the neural cells of IB-9 with the histologic patterns of primitive CNS neuroepithelium results from tyrosinase activity only and is therefore unrelated to the metabolic pathways involved in catecholamine synthesis and degradation. It is suggested that, at this stage of differentiation and in this system, the expression of catecholamine synthesis via tyrosine hydroxylase in neuroepithelial cells, and of melanin pigment via tyrosinase, are probably mutually exclusive.
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  • 6
    ISSN: 1432-2307
    Keywords: Mouse teratoma ; Embryoid bodies ; Cerebral transplantion ; Neural differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Small embryoid bodies (EB's) from the OTT-6050 transplantable mouse teratoma, obtained by gravity filtration through a 74 μ mesh, were injected into the right cerebral hemisphere of syngeneic newborn or adult mice of both sexes in order to produce differentiating teratomas after a single passage. In subsequent experiments, two solid tumors resulting from two different EB-implants into the brains of adult hosts were used to initiate sequential tumors and were carried intracerebrally in adult mice for 12 and 18 passages respectively. The animals were sacrificed when signs of increased intracranial pressure developed. Survival times were as follows: single passages in adult mice: mean, 35 days; single passages in neonatal mice: mean, 19 days; sequential passages in adult mice: mean, 25 days. Multipotential stem cells accounted for l/2 to 3/4 of the cens in all tumors. Primitive neural cells, ependymoblastic rosettes, neuroblasts and glia were present in all; stem cells, primitive neural cells and rosettes decreased proportionately as the more differentiated neural populations became prominent. Mature ganglion cells were found only in the sequentially passaged tumors and in tumors maintained for more than one month after a single passage in adult mice. Synapses were noted in the most differentiated areas. Neuroblasts were infrequent in tumors developing in neonatal hosts, and mature ganglion cells were absent. Glial fibrillary acidic protein was present by the 24th day in tumors obtained in adult hosts after single passage and in sequential passages. Both in the OTT-6050-derived tumor fractions IB-9 and IB-21, previously reported, and in the EB-derived tumors described in the present study the cerebral microenvironment did not appear to have unique properties favoring neural differentiation and maturation, since similar neural features were found in their subcutaneous counterparts. The findings reported suggest that any accentuation of neuroepithelial differentiation elicited by injecting EB's either intracerebrally or subcutaneously is apparently directly related to the total time of in vivo maintenance of the tumor and therefore presumably to the length of time necessary for such maturation to occur.
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  • 7
    ISSN: 1432-0533
    Keywords: Cerebellar medulloblastoma in vitro ; Organ culture ; Divergent differentiation ; Astrocytic and neuroblastic ; Synaptic ribbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A cerebellar medulloblastoma from a 2-year-old boy was maintained in vitro in an organ culture system for 6.5 months, and the explants studied by light and electron microscopy at different time intervals. The tumor cells progressively demonstrated divergent differentiation into astrocytes and neuroblasts. Astrocytic differentiation, confirmed by immunohistochemistry for GFA protein, became maximal after about 7 weeks in vitro and was thereafter maintained in different areas of the explants. Concomitantly, neuroblastic differentiation was expressed in other cells, with the progressive development of cell processes filled with many microtubules, of neuroblastic rosettes, of increased numbers of densecore and clear-centered vesicles, of occasional 9+0 cilia, and of synaptic ribbons appearing in vitro. Neuroblastic differentiation was most pronounced in 4- and 6-month-old explants, but synapses were not found. The differentiating features reported are in contrast to those of the orignial tumor, which was largely undifferentiated. The alternative interpretation of a divergent glial and pineocytic differentiation is also considered. These findings support the concept of the differentiating bipotential of the cerebellar medulloblastoma.
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  • 8
    ISSN: 1432-0533
    Keywords: Hemangioendothelioma ; Endothelial cells ; Matrix culture ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two thorium dioxide-induced murine hemangioendotheliomas, 42021 TCT and 44347 TST, were grown subcutaneously (for up to 22 and 15 passages respectively) or intracranially (single passage) and were adapted to culture as a monolayer and, in a limited fashion, in an organ culture system or in rotary suspension. They remained viable and malignant following 20–21 years of storage in liquid nitrogen, and had ultrastructural similarities to human hemangioblastomas. The murine tumors were positive for Griffonia (Bandeiraea) simplicofolia isolectin B4 binding, establishing their endothelial nature; however, unlike human hemangioblastic tumors, they did not cross-react with antisera to human factor VIII or fibronectin and they did not demonstrate Ulex europaeus type I lectin (UEA I) binding (as is also the case for non-neoplastic murine vascular endothelial cells). A variety of morphological cell types in cultures derived from the tumors were also positive for Griffonia (Bandeiraea) simplicifolia isolectin B4 binding. Both murine hemangioendotheliomas, when implanted in the cerebrum, were potent inducers of reactive gliosis, but there was no evidence of uptake of glial fibrillary acidic protein. Unlike the human cerebellar hemangioblastomas, murine tumors were malignant and invasive and did not contain stromal cells, nor did they demonstrate Weibel-Palade bodies or extensive pinocytotic activity. Thus, the murine tumors appear to more closely resemble angiosarcomas or epitheloid hemangioblastomas than the cerebellar hemangioblastomas.
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  • 9
    ISSN: 1432-0533
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Licht- und elektronenoptische Untersuchungen wurden an einem menschlichen Glioblastoma multiforme durchgeführt, das 17 Jahre hindurch am heterologen Wachstum im Meerschweinchen erhalten wurde. Unterarten des Tumors im Gehirn und Auge wurden untersucht. Lichtmikroskopisch hatte der Tumor die morphologischen Merkmale des Glioblastoms verloren und baute sich fast ausschließlich aus Spongioblasten auf, wie Silberfärbungen zeigten. Die Ultrastruktur der Tumorzellen ähnelte der von Astrocyten, wie sie in Astrocytomen beschrieben wurden. Die langgestreckten, spindelförmigen Zellen zeigten einen normalen Aufbau der üblichen Zellorganellen. Sie enthielten auch reichlich hervortretende cytoplasmatische Fibrillen, deren Morphologie eine repetitive strukturelle Untergruppierung vermuten lassen, sowie häufige cytoplasmatische Vacuolen und Einschlüsse von erheblicher Variabilität. Die Morphologie der im Gehirn und im Auge wachsenden Tumorzellen war ähnlich, doch erwies sich die Architektur im Gehirntumor als lockerer und zeigte eine relative Zunahme des extracellulären Raumes.
    Notes: Summary Studies with the light and the electron microscope were carried out on a human glioblastoma multiforme maintained for 17 years in heterologous growth in the guinea pig. Sublines of the tumor growing in the brain and in the eye were studied. With the light microscope the tumor had lost the morphological characteristics of glioblastoma and was composed almost entirely of spongioblasts as judged by metallic stains. The ultrastructure of the tumor cells was similar to that of astrocytes in astrocytomas as described by others. The elongated spindle-shaped cells contained a normal complement of the usual cytoplasmic organelles. They also contained prominent cytoplasmic fibrils, whose morphology suggested a repetitive structural subunit; and frequent cytoplasmic vacuoles and inclusions displaying considerable variation. The morphology of the tumor cells growing in the brain and eye was similar, but in the brain tumor the architecture was looser and there was a relative increase in extracellular space.
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  • 10
    ISSN: 1432-0533
    Keywords: Neuronal Ceroid Lipofuscinosis ; Electron Microscopy ; Membranous and Fingerprint Inclusions ; Hypertrophied Cortical Astrocytes ; Nuclear Bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommaire Deux cas de la maladie de Batten-Spielmeyer-Vogt (idiotie amaurotique familiale juvénile) ont été étudiés en microscopie électronique, histochimiquement et biochimiquement. Le premier cas, dont l'histoire clinique a débuté à l'âge de 3 ans, a révélé des inclusions cytoplasmiques dans les cellules neuronales et gliales, composées de membranes fréquemment disposées en paires. La structure de ces inclusions était identique à l'examen du matériel autopsié six mois plus tard. Dans le deuxième cas, dont l'histoire clinique date de 4 ans et 4 mois, les inclusions étaient plus pléomorphes: elles étaient en général plus denses en électronique et comportaient fréquemment un élément à l'aspect d'«empreintes digitales». Quelques inclusions membraneuses semblables à celles du premier cas y ont également été retrouvées. En outre ont été observées une hypertrophie cytoplasmique prononcée des astrocytes corticaux, et une grande fréquence de cils, de corps basaux et de corps nucléaires dans ces astrocytes. Un paquet de filaments intranucléaires a été observé dans un neuron. Les données neurochimiques n'ont révélé aucune abnormalité dans les lipides ou les protéines du premier cas, ou dans les gangliosides du second. Malgré les différences morphologiques qui les caractérisent, la présence simultanée des deux types d'inclusions cytoplasmiques dans le même cas suggère qu'elles peuvent représenter des stages divers dans l'évolution du même processus fondamental. Il est possible que ce soit l'âge de la cellule nerveuse, lors de l'atteinte métabolique dont elle est l'object, qui détermine ces différences.
    Notes: Summary Electron microscopic, histochemical and neurochemical studies on two cases of Batten-Spielmeyer-Vogt disease (juvenile amaurotic familial idiocy) are presented. In the first case, with the clinical onset at the age of 3 years, cytoplasmic neuronal and glial inclusions consisted of membranous bodies, the membranes of which were frequently paired. The fine structure of these inclusions was unaltered when examined in autopsy material 6 months later. In case 2, with the clinical onset at 4 years and 4 months, the inclusions were more pleomorphic: they were usually more electron-dense, and frequently showed a characteristic “fingerprint” pattern component. A few membranous inclusions resembling those in case 1 were also present. Additional findings included marked cytoplasmic hypertrophy of inclusion-containing cortical astrocytes, and frequent cytoplasmic cilia, basal bodies, and nuclear bodies in the hypertrophic astrocytes. A packet of intranuclear filaments was found in one neuron. Neurochemical studies failed to reveal any abnormality of lipid or protein pattern in case 1, or of ganglioside pattern in case 2. Despite the morphological differences between the two types of cytoplasmic inclusions, the presence of both types within the same case suggests that they may represent different stages in the evolution of a single process. It is conceivable that such differences are related to the age of the neuron when the postulated intracellular defect first becomes manifest.
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