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  • 1
    ISSN: 0942-0940
    Keywords: Malignant rhabdoid tumour ; atypical teratoid/rhabdoid tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of primary rhabdoid tumour of the CNS (RT-CNS) are presented. In case 1 a hemispheric tumour developed in a 10.5 months old girl, who survived for 6 months after incomplete resection, radio- and polychemotherapy. Case 2 was a 4 years and 8 months old boy with a large IIIrd ventricle tumour, who died of leptomeningeal tumour dissemination 7 months after diagnosis despite radiotherapy. In case 3 a pineal mass occurring in a 14 month old female was radioresistant and totally exstirpated. The child died due to tumour recurrence two months later. Autopsy examination revealed widespread leptomeningeal dissemination. All three cases fulfilled light and electron microscopic criteria of RT-CNS including abundant eosinophilic cytoplasm, vesicular nuclei with large nucleoli and conspicuous anti-vimentin positive filaments. Extensive immunohistochemical studies showed expression of epithelial (EMA, KL1), macrophage (alpha-1 antichymotrypsin), neuro-ectodermal (GFAP, NSE, β-tubulin III) and myogenic markers (desmin, actin). Different stress proteins (alpha-B crystallin, HSP70) were also expressed. Tumour cells showed a proliferation (MIB1) index of 28.4% (case 1) and 33.4% (case 2). From our study it can be concluded that RT-CNS reveals significant immuno-morphological heterogeneity thus supporting the view that it is not a specific pathological entity but merely a phenotypic appearance of different neoplasms, some of which are linked to primitive neuro-ectodermal tumours.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: GTP-binding rab proteins, present in synaptic vesicles and endocrine secretory granules, have been shown to be involved in the control of regulated exocytosis. We found rab3 proteins in immunoblots of diverse areas of the mouse central nervous system (spinal cord, olfactory bulb, hippocampus, cerebellum and neocortex). Immunohistochemical observations at light- and electron-microscopical levels in the hippocampus and other areas revealed rab3 proteins in virtually all synaptic fields and terminals of the areas investigated. In the retina, rab3A immunoreactivity was confined to the inner and outer plexiform layers. Ultrastructural examination revealed that rab3A was present in conventional terminals in the inner plexiform layer and in horizontal cell processes of the outer plexiform layer. In contrast ribbon synapses, which play a key role in transferring information from the photoreceptor cells to the central nervous system, were immunonegative. We also tested whether other proteins of the rab3 family are present in ribbon synapses. However, using an antibody recognizing rab3B and rab3C in addition to rab3A, we found no immunoreactivity in these synapses. Interestingly, we observed also no immunoreactivity for synaptosomal-associated protein 25 (SNAP-25) in ribbon synapses, but conventional synapses and horizontal cell processes were heavily stained. Our data show that the known rab3 and SNAP-25 isoforms, which are components of the secretory apparatus of conventional synapses, are absent from ribbon synapses of the retina. Our observations suggest different mechanisms of transmitter exocytosis in conventional and ribbon terminals.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 29 (1996), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The biological behaviour of meningeal haemangiopericytomas was retrospectively studied using immunohistochemical staining with MIB1, a monoclonal antibody against the Ki-67 antigen, a nuclear protein related to cell proliferation. Paraffin-embedded material from 62 tumours from 40 patients were investigated. The proliferating compartment of the tumours was estimated by evaluating the MIB1 staining index, i.e. the percentage of MIB1 positive nuclei in at least 1000 counted tumour cells in representative areas. The staining index ranged from 1.24% to 39.01%. Statistical analysis revealed no significant correlation between the staining index and recurrence-free survival (χ2 = 0.3922, P = 0.5311). Long-term observation (〉100 months), however, revealed a tendency to longer survival in the group with a staining index less than 5%. According to our results, the MIB1 staining index does not contribute to the accuracy of predicting the clinical outcome of meningeal haemangiopericytomas.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 67-69 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Dispersion of the ordinary and extraordinary indices of refraction for wurtzite AlxGa1−xN epitaxial layers with x=0.00, 0.04, 0.08, 0.11, and 0.20 in the range of wavelengths 457〈λ〈980 nm were measured via a prism-coupled waveguide technique. The quantitative accuracy of x is ±10% and the accuracy of the refractive indices is ∼±0.01. The dispersion is found to be well described by a 1st-order Sellmeier dispersion formula. A simple functional form is presented that allows calculation of the refractive indices as functions of x and λ. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3188-3190 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The room-temperature absorption coefficient and ordinary refractive index for a ∼0.4-μm-thick p-type wurtzite Al0.09Ga0.91N epitaxial layer were determined via optical transmission measurements. The layer was grown by metal organic chemical vapor deposition and heavily doped (∼5×1019 cm−3) with Mg. Additional measurements of the refractive index by prism coupling to the layer confirmed the transmission results. The low-temperature AlN buffer layer altered the expected interference fringes of the transmission spectrum below the band-gap energy and had to be accounted for in the analysis. The absorption coefficient exhibited band-tail effects and had a reduced slope near band-gap energy as compared to undoped GaN. Using a detailed balance argument, the reduced slope was consistent with the lack of a peak in the continuous-wave photoluminescent emission. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 1196-1203 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optical-field profiles in wide-band-gap AlxGa1−xN/InxGa1−xN multiple-quantum well (MQW) separate-confinement heterostructure (SCH) laser diodes (LDs) were calculated using a 2×2 transfer-matrix approach that accommodates complex refractive indices. The refractive indices of AlxGa1−xN and InxGa1−xN were approximated by shifting the refractive index of GaN according to the band-gap energy of the solid solution. Current LDs were analyzed and show reasonable optical confinement. Optimization of the SCH waveguide for a three MQW active region was performed by varying the waveguide and cladding layer thicknesses. For 0.8μm thick Al0.10Ga0.90N cladding layers, waveguides on sapphire and SiC substrates had a maximum confinement factor of ∼3.3%. Layers outside of the waveguide strongly affected the optical field for thin (∼0.4 μm) cladding layer thicknesses and resulted in resonant coupling of the light out of the waveguide. Sapphire substrates were found to enhance light confinement, while SiC substrates were found to reduce optical confinement as the cladding layer thickness is reduced. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1439-0973
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epididymal, testicular, and prostatic tissue penetration of sparfloxacin, a new quinolone, was assessed in a rat model of acute epididymitis. Seventy-two hours after injection of 0.1 ml (106 cfu/ml) of anEscherichia coli suspension into the right epididymis via the right ductus deferens, a single oral dose of sparfloxacin 50 mg/kg body weight was administered. One, 2, 4, 8, 12, and 24 h after administration the animals were sacrificed and the sparfloxacin concentrations and “areas under the curve” (AUC0–24) in both epididymides, both testes, the prostate gland and in the serum were measured by bioassay. The highest mean AUC0–24 was found in the prostate gland, followed by left epididymis, right epididymis, serum, right testis, and left testis (190, 79, 60, 28, 12, and 9 mg/kg×h, respectively). Though there was no statistically significant difference in the sparfloxacin concentration of both epididymides (p=0.09), the mean AUC0–24 was significantly higher in the non-infected left epididymis (p〈0.0001). The AUC0–24 and sparfloxacin concentrations of the right infected epididymis were significantly higher than those observed in the serum (p〈0.0001). In both testes, the AUC0–24 and sparfloxacin concentrations were lower than in the serum (p〈0.0001), however, the concentration exceeded the MIC tenfold for approximately 20 h. It is concluded that the pharmacokinetic properties of sparfloxacin (goodin vitro activity, high penetration into the prostate gland, testes, infected and non-infected epididymides) make this drug a recommendable choice for the initial treatment of acute epididymitis caused byE. coli.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2013
    Keywords: Key words Isotopic analysis ; Overall fractionation factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In this study we investigated the contribution of diffusion limitation to the exercise-induced hypoxaemia in interstitial lung disease (ILD). We applied isotopic analysis to the composition of the stable isotopic oxygen molecules 16O2 and 16O18O in expiratory gas mixtures obtained from six ILD patients and six healthy subjects at rest and during ergometer work (60 W). The changes in the 16O18O/16O2 ratios were interpreted by using the overall fractionation factor of respiration (α O) which would be increased towards 1.03 on increasing diffusion limitation. In addition, the O2 partial pressures of alveolar gas and arterial blood (P AO2, P aO2) were determined. In the patients, α O was significantly reduced from 1.0066 ± 0.0004 (mean ± SD) at rest to 1.0035 ± 0.0004 during exercise and in the healthy subjects from 1.0072 ± 0.0008 to 1.0044 ± 0.0004. Furthermore, the exercise-induced reduction of P aO2 (from 77 to 69 mmHg) was due to a drop of alveolar PO2 found in each patient, whereas in each healthy subject P aO2 was increased on exercise. On the basis of a resistance model we conclude that the patients’ data were inconsistent with increasing diffusion limitation but showed an increasing impairment of O2 transport by ventilation.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0533
    Keywords: Key words Frontotemporal dementia ; Dementia of ; frontal lobe type ; Pick’s disease ; Motor neuron disease ; with dementia ; Pick bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Histological and immunohistochemical findings in 20 cases of frontotemporal dementias – 8 cases of dementia of frontal lobe type (DFT), 7 cases of Pick’s disease (PD), and 5 cases of motor neuron disease with dementia (MND/D) – are presented. Common features of all three syndromes were: frontotemporal atrophy, involvement of subcortical nuclei, and swollen chromatolytic cells. Ubiquitin (Ub)-positive and tau-negative inclusions in cortical, hippocampal, and motor neurons were found in MND/D and DFT cases, suggesting a common pathogenesis of MND/D and DFT. MND/D showed the same cytoskeletal alterations in motor nuclei as MND without dementia: Bunina bodies and skein-like, Ub-positive inclusions. DFT differed from PD in the preponderance of histopathological changes in upper cortical layers, the sparseness of chromatolytic cells, and the absence of tau-positive Pick bodies (PBs). There were, however, two transitional cases showing Pick-type histology but no PBs, thus linking DFT and PD. PBs expressed chromogranin B and secretoneurin strongly, but chromogranin A only weakly. They were negative for the 70-kDa heat-shock protein, metallothionein, and glutathione-S-transferase.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0533
    Keywords: Key words Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) ; Hereditary multi-infarct dementia ; Skin biopsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized clinically by recurrent cerebral infarcts, subcortical dementia and pseudobulbar palsy, and morphologically by a granular degeneration of cerebral and, to a lesser degree, extracerebral blood vessels. We present morphological findings in a further German family affected by CADASIL. The index case showed the typical periodic acid-Schiff-positive granular degeneration of vascular smooth muscle cells (VSMC) in cerebral vessels, which did not react with antibodies against various immunoglobulins or complement factors. Ultrastructurally, granular osmiophilic material (GOM) covered the VSMC in different cerebral regions as well as in extracerebral organs (muscle, nerve, skin, small and large intestine, liver, kidney and heart). Skin biopsy samples from other family members of the last two generations also revealed GOM irrespective of the clinical symptomatology (CADASIL, migraine only or asymptomatic). Patients in the third generation had higher amounts of GOM in skin vessels than did asymptomatic or migraine patients in the fourth generation. We conclude that skin biopsy is a useful and less-invasive screening method for the differential diagnosis of CADASIL.
    Type of Medium: Electronic Resource
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