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  • 1
    ISSN: 1432-0533
    Keywords: Astrocyte ; Macrophage ; Lymphocyte ; Major histocompatibility complex antigens ; Cellular immunity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Frozen samples from 23 low grade (grade I and II) astrocytomas were studied by means of a panel of monoclonal antibodies to macrophages, lymphocytes (and their subsets) and HLA-DR antigens. Macrophages were present in low to moderate numbers in 38%–86% of cases, the variance in figures depending on the antibody used. T lymphocytes, the majority of CD8 phenotype, were detected in low numbers in 78% of tumours. B lymphocytes were scanty in 22% (5/22) and totally absent in the remaining cases. HLA-DR antigen was expressed by tumour cells in 35% (6/17) of cases. These findings indicate that in some low grade astrocytomas there is a mononuclear cell infiltrate with macrophages and secondarily CD8+lymphocytes playing the major role. The significance of these findings remains speculative at present.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 79 (1989), S. 205-210 
    ISSN: 1432-0533
    Keywords: Medulloblastoma ; Immunohistology ; Primitive neuroectodermal tumour ; Brain tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fifty paraffin-embedded medulloblastomas (31 in children and 19 in adults) were reacted with a panel of ten antibodies to glial, neuronal, mesodermal and epithelial antigens. The tumours were divided according to their histological features into three groups: classic, desmoplastic and highly vascular. Reactivity for glial fibrillary acidic protein was observed in 20 cases. Forty tumours reacted with PGP9.5 (neuronal marker) in clusters of poorly differentiated cells, cell cords and some scattered cells. Cells forming rosettes were mostly negative except for slight central reactivity. Eight of the 40 tumours contained neurofilaments. In scattered cells somatic reactivity for vimentin was found in 14 tumours. Ten cases showed positivity for S-100 with a nuclear and perinuclear pattern. No difference in reactivity in relation with age was observed. Desmoplastic medulloblastomas showed less reactivity for glial and neural markers. It was concluded that medulloblastoma shows degrees of differentiation as evidenced by the expression of various proteins. Differentiation occurs along two lines: glial and/or neuronal. Most tumours also contain a component of poorly differentiated cells which may differentiate into one of these two lines or act as primarily stem cells.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Glioma ; Macrophage ; Lymphocyte ; Cellular immunity ; Major histocompatibility complex antigens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sixty-five malignant gliomas (astrocytomas grade 3 and 4 and glioblastomas) were examined by means of immunoperoxidase staining on frozen tissue using various monoclonal antibodies directed against macrophages, lymphocytes and natural killer cells. Depending on the antibody used, the presence of macrophages in tumours ranged from 85%–100%. Many of the tumours contained substantial numbers of macrophages not only, as expected, in necrotic areas but also in intact tumour tissue. Eighty-nine percent of 39 tumours tested contained Fc receptorbearing mononuclear cells in viable tumour. In 100% of 44 tumours tested for HLADR class 2 major histocompatibility complex antigen this antigen was detected in the macrophages. In 40% of these 44 cases, HLADR antigen was also present on the tumour cells. Eighty-eight percent of 53 tumours tested contained T cells in viable tumour and the majority of these cells were T cytotoxic/suppressor (T8). Twenty-four percent of 33 tumours contained no T helper/inducer (T4) lymphocytes and in the other 76% there were few positive cells. Only 9% of 21 tumours contained natural killer cells (NK). B cells were absent from 88% of 61 tumours and almost all of the remainder contained only a small number of B cells. The findings are discussed with reference to a possible host immune response to gliomas and relevant literature is reviewed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 62 (1986), S. 312-320 
    ISSN: 1432-1106
    Keywords: Isolated frog labyrinth ; Excitatory-inhibitory rotational stimuli ; First order canal neuron dynamics ; Non-linearities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary EPSPs and spikes were recorded at rest and during rotation from single fibres of the posterior nerve in the isolated frog labyrinth. The spike discharge properties of 57 units were examined at rest and during repetitive acceleratory-velocity steps. Forty of these units were subjected to excitatory steps of 5–12 s duration and 45% displayed an evident discharge adaptation. In the non-adapting units, the excitatory response also deviated from that expected on the basis of the torsion-pendulum model and exhibited an exponential time-course in only 36% of the fibres examined. The time constant T2 of the response rising phase was significantly longer than that of the decay (2.5 s versus 1.7 s). When all the 57 units were considered, a linear behaviour was found in 67%. The average gain in these linear units was 1.9 ± 1.4 spikes · s−1/deg · s−2. Adaptive fibres exhibited a lower resting firing rate and a higher gain (3.8 spikes/s and 2.3 spikes · s−1/deg · s−2, respectively) when compared with the non-adapting ones (7.1 spikes/s and 1.5 spikes · s−1/deg · s−2). An undershoot was present in 57% of the units; it increased with acceleration and was not strictly related to adaptation. Fifteen of the 40 units tested with the 5–12 s duration excitatory steps survived repeated inhibitory accelerations of the same duration. In these units a marked response asymmetry was evident since their resting activity could be abolished by accelerations not larger than 10 deg/s2. In 40% of the units inhibited by acceleration the mean response was proportional to the stimulus logarithm, while the others saturated for weak stimulations. A consistent overshoot of the discharge was evident in most of the units (60%). Analysis of the EPSP emission rates demonstrates that even a 10–20% increase in their frequency during excitation results in a two-three fold increase in the corresponding spike frequency. Similarly, a decrease of 15–35% in their numbers during inhibition is sufficient to completely block the spike firing. These findings reveal the high sensitivity of the afferent synapse, spike discharge being modulated by slight modifications in the release of the excitatory transmitter.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Histopathology 15 (1989), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eleven benign and five malignant choroid plexus papillomas in children and adults were studied immunohistologically with a panel of antibodies against glial fibrillary acidic protein, S-100 protein, vimentin, desmin, epithelial membrane antigen and two different cytokeratins (LP34 and CAM 5.2). Glial fibrillary acidic protein was focally present in epithelial tumour cells, in cells within solid areas and in clusters of cells within the stroma. S-100 protein was diffusely present in tumour cells with focal accentuation. Vimentin was present in all cases, the epithelial tumour cells demonstrating strong and diffuse positivity with perinuclear accentuation; malignant tumours, however, showed stronger positivity than benign ones. Desmin was negative in all tumours. Epithelial membrane antigen and cytokeratin (LP34) were demonstrated in four of five malignant tumours but were absent in the benign ones; CAM 5.2 reacted with four of five malignant tumours and also reacted with eight of the 11 benign ones. The significance of these findings is discussed in respect of the ontogeny of these tumours.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Histopathology 13 (1988), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Sixty-six ependymomas were examined immunohistologically to determine their distribution of glial fibrillary acidic proteins, S-100 protein and vimentin. The neoplasms were subdivided into four groups: (1) ependymomas from the cauda equina, predominantly of the myxopapillary type; (2) benign ependymomas; (3) malignant ependymomas; and (4) ependymoblastomas. Marked differences in antigen reactivity were observed between each group. The intensity of the reaction with the three antibodies was strongest in malignant ependymomas. Ependymomas from the cauda equina showed a patchy distribution of positivity for the three antigens in cells surrounding blood vessels but there was no staining of collagenous septa or the myxoid areas. In ependymoblastomas, the cells of the rosettes were negative for glial fibrillary acidic protein, but there was focal positivity for vimentin and S-100. Other areas showed tumour cells containing moderate amounts of vimentin and small amounts of S-100, and a few bands of filaments positive for glial fibrillary acidic protein. The cytogenetic and biological implications of these findings are discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 16 (2002), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We investigated the possibility that, in hair cells mechanically isolated from frog semicircular canals, Ca2+ extrusion occurs via a Na+ : Ca2+ (cardiac type) or a Na+ : Ca2+,K+ (retinal type) exchanger. Cells concurrently imaged during whole-cell patch-clamp recordings using the Ca2+ sensitive fluorescent dye Oregon Green 488 BAPTA-1 (100 µm) showed no voltage dependence of Ca2+ clearance dynamics following a Ca2+ load through voltage-gated Ca2+ channels. Reverse exchange was probed in hair cells dialyzed with a Ca2+- and K+-free solution, containing a Na+ concentration that saturates the exchanger, after zeroing the contribution to the whole-cell current from Ca2+ and K+ conductances. In these conditions, no reverse exchange current was detected upon switching from a Ca2+-free external solution to a solution containing concentrations of Ca2+ alone, or Ca2+ + K+ that saturated the exchanger. By contrast, the same experimental protocol elicited peak exchange currents exceeding 100 pA in gecko rod photoreceptors, used as positive controls. In both cell types, we also probed the forward mode of the exchanger by rapidly increasing the intracellular Ca2+ concentration using flash photolysis of two novel caged Ca2+ complexes, calcium 2,2′-{[1-(2-nitrophenyl)ethane-1,2-diyl]bis(oxy)}bis(acetate) and calcium 2,2′-{[1-(4,5-dimethoxy-2-nitrophenyl)ethane-1,2-diyl]bis(oxy)} bis(acetate), in the presence of internal K+ and external Na+. No currents were evoked by UV-triggered Ca2+ jumps in hair cells, whereas exchanger conformational currents up to 400 pA, followed by saturating forward exchange currents up to 40 pA, were recorded in rod photoreceptors subjected to the same experimental conditions. We conclude that no functional electrogenic exchanger is present in this hair cell population, which leaves the abundant plasma membrane Ca2+-ATPases as the primary contributors to Ca2+ extrusion.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd.
    Child 28 (2002), S. 0 
    ISSN: 1365-2214
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Detailed stereological analyses of specific regions of brains of children who had died from Sudden Infant Death Syndrome (SIDS) was undertaken to determine whether global evidence of an underlying pathology exists, contributing to an increased susceptibility to SIDS. A significant reduction in the total number of neocortical neurones and neurone volume was observed in SIDS normal birth weight (NBW) infants in comparison to controls. A significant reduction in both volume and total neurone number were also noted in the dorsal motor nucleus of the vagus in SIDS NBW group when compared with controls. Anomalies in regions of the brain involved with cardiorespiratory control (brainstem) and arousal (brainstem and neocortex) may play a crucial role in the chain of events resulting in a SIDS event.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1435-1463
    Keywords: Aging ; amyotrophic lateral sclerosis ; synaptophysin ; brain aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Aged-related spinal cord changes such as neuronal loss have been related to the degree of clinical severity of amyotrophic lateral sclerosis (ALS); morphological data on synapses are, however, wanting. Variations in synaptophysin (Sph) expression in aging and ALS were thus studied at the level of lower motor neurons in 40 controls with non-neurological diseases and 11 cases of ALS. Control sections of formalin fixed paraffin embedded cervical (C7/8), thoracic (T10) and lumbar spinal cord (L5) and C6, C7, C8 and L5 of ALS cases were stained with haematoxylin and eosin, luxol fast blue (LFB), and immunostained with a mouse monoclonal antibody against Sph. The neuropil of the anterior horn (AH) in all control cases demonstrated Sph positivity. A dot-like pattern of positivity of presynaptic terminals on soma of motor neurons and fine immunoreactivity along neuronal processes were observed. A significant reduction of Sph immunostaining was observed in the neuropil with increasing age and 3 different somatic patterns were seen: a-well preserved Sph reactivity around the soma and the proximal dendrites of histologically normal neurons; b-few chromatolytic neurons showing large numbers of dot-like presynaptic terminals around the cell body and in a “fused” pattern; c-intense, diffuse, and homogeneous reactivity of some neurons. Attenuation of Sph reactivity in the AH neuropil, to its complete loss, was observed in all ALS cases. In addition to patterns a-c, two additional microscopic findings were noted in ALS: d-chromatolytic neurons showing complete absence of Sph reactivity; e-absence of Sph reactivity around the soma and the proximal dendrites of histologically normal surviving neurons. Our findings demonstrate that there is a decrease in Sph immunostaining with aging, thus suggesting an alteration in dendritic networks of the AH with aging. Changes in the pattern of Sph immunoreactivity in cell bodies may represent synaptic plasticity and/or degeneration. Reinnervation may also be a possible mechanism as a response to neuronal loss in oldest control cases. Sph reactivity results may thus lend support to the presence of superimposed aging components in ALS cases which may give an insight into explaining the increasing severity of the disease which is encountered with advancing age.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1435-1463
    Keywords: Keywords: Aging ; motor neuron ; cytoskeletal abnormalities ; amyotrophic lateral sclerosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary. In order to identify possible morphological changes which occur in the anterior horn of normal individuals during aging, 40 controls with no neurological disease were studied. Brain and spinal cord tissue was processed according to a brain banking protocol. Controls were grouped according to age in 10 year intervals. Serial sections (20 μm) of formalin fixed, paraffin-embedded tissue were obtained, from each cervical, thoracic and lumbar spinal cord segment. Every 5th section (until 2mm) was stained with haematoxylin and eosin and the numbers of motor neurons in the anterior horn counted at ×400 magnification. Descriptive statistical analysis was performed using the SPSS program. Parallel sections (5 μm) of the same spinal segments were immunostained with a panel of antibodies including glial fibrillary acidic protein (GFAP), tau, ubiquitin and two phosphorylated neurofilaments subunits. Significant neuronal loss with aging was found by regression line analysis where three equations were used to calculate the number of motor neurons by age in each spinal segment. In 24/40 cases spheroids were observed and they were more numerous in the lumbar segment. GFAP staining revealed a distinctive cellular pattern in the anterior horn of oldest cases. Large and intensely stained astrocytes were seen in the anterior horn of cases aged over 75 years. The number of astrocytes increased progressively with age up to 70 years. Some of the changes observed in the present study may be the result of a selective vulnerability of large motor neurons to aging which could play an important role in the progression of MND. Most of these changes may also have similar pathophysiological mechanisms.
    Type of Medium: Electronic Resource
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