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  • 1
    Electronic Resource
    Electronic Resource
    Tumor induction by ras and myc oncogenes in fetal and neonatal brain: modulating effects of developmental stage and retroviral dose (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 456-465 
    Details
    ISSN: 1432-0533
    Keywords: Retroviral vectors ; Oncogene-ras-myc ; Grafting ; Brain tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Introduction into fetal rat brain cells of a replication-defective retroviral vector harboring v-Ha-ras and v-gag-myc rapidly causes the induction of highly malignant undifferentiated neuroectodermal tumors following transplantation into the brains of syngeneic hosts [Wiestler, et al. (1992) Cancer Res. 52: 3760–3767]. In the present study, we have investigated the modulating effect of the developmental stage of neural target cells and of the dose of the retroviral vector used in the grafting experiments. Exposure of fetal cells from embryonic day (E)12 or E14 produced a 100% incidence of malignant neuroectodermal tumors which led to the death of recipient animals after a median latency period of 32 days. A 100-fold reduction of the virus dose from 2.062×106 to 2.062×104 focus-forming units/ml resulted in a lower tumor incidence of 25%. Of six neural grafts exposed to v-Ha-ras and v-myc at E16, only one showed evidence of tumorigenesis (low-grade astrocytoma and hemangioma). All other transplants were morphologically normal for observation periods of 26 weeks, indicating a marked loss of transforming activity of ras and myc in more advanced stages of brain development. In retrovirus-exposed donor cells which caused the development of neural tumors in recipient rats, malignant transformation was also evident during culture in vitro, usually after 9–12 days. Oncogene complementation was also studied in the newborn rat brain. After microinjection of the retroviral vector into the brain at postnatal day (P)0, P1 and P3, 5 out of 20 animals (25%) developed a total of seven brain tumors. Histopathologically, three of these neoplasms were malignant neuroectodermal tumors which, in contrast to those induced in fetal brain transplants showed evidence of focal glial and/or neuronal differentiation. In addition, we observed one oligodendroglioma, two hemangiomas and a malignant hemangioendothelioma. These data indicate that neural precursor cells and endothelia of the rat brain represent the major target cells for the complementary action of ras and myc and that the use of target cells from later developmental stages (E16 and postnatal) leads to the induction of both primitive and more differentiated neoplasms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228580
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  • 2
    Electronic Resource
    Electronic Resource
    Troyer syndrome: a combination of central brain abnormality and motor neuron disease? (1999)
    Springer
    Journal of neurology 246 (1999), S. 556-561 
    Details
    ISSN: 1432-1459
    Keywords: Key words Troyer syndrome ; Motor neuron disease ; Thin corpus ; callosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Hereditary spastic paraplegia is a group of clinically and genetically heterogeneous disorders consisting of pure and complicated forms. A variant with the additional features of severe atrophy of the small hand muscles, dysarthria, mental retardation, and short stature has been termed Troyer syndrome (MIM#275900) after the name of Old Order Amish families suffering from these symptoms. We report here an Austrian family with two individuals who exhibit all the features of Troyer syndrome, and provide additional data on this disorder. Electrophysiological studies showed chronic denervation and reduced motor nerve conduction velocities but normal sensory potentials. Muscle biopsy revealed a neurogenic pattern while the sural nerve was normal on histological examination. Brain abnormalities on magnetic resonance imaging consisted of a thin corpus callosum with a poorly developed cingulate gyrus and mild periventricular signal hyperintensities. These findings characterize the Troyer syndrome as a disorder of the first and second motor neuron with additional damage in the brain. The morphological features observed in this family may contribute to the grouping and subsequent understanding of complicated forms of hereditary spastic paraplegia, together with similar observations in other, more recently reported families.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004150050403
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  • 3
    Electronic Resource
    Electronic Resource
    Invasive Ductal Carcinoma of the Male Breast Expanding From Pacemaker Pocket Decubitus (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 22 (1999), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: After twenty-five Years of therapy with different unifocal pacemaking systems, an 84-year old male patient developed a nonseptic pacemaker decubitus. A rare incidental finding of invasive ductal carcinoma of the right mammary gland was surgically treated by a generous excision of the tumor and by consecutive modified radical mastectomy. According to published literature, the association of invasive ductal carcinoma arising from a pacemaker pocket decubitus and followed by curative treatment has not been previously reported. We do conclude that pacemaker generators in close relationship to the mammary gland should be considered with suspicion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1999.tb00484.x
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  • 4
    Electronic Resource
    Electronic Resource
    Corneal Langerhans cells during storage in organ culture medium (1997)
    Springer
    Der Ophthalmologe 94 (1997), S. 703-706 
    Details
    ISSN: 1433-0423
    Keywords: Key words Flow cytometry • HLA-DR • Langerhans cells • Organ culture ; Schlüsselwörter Flußzytometrie • HLA-DR • Langerhans-Zellen • Organkultur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Hintergrund: HLA-DR-Antigene der Kornea gehen im Rahmen einer Organkulturlagerung verloren. Diese Arbeit untersuchte, ob es sich dabei um eine Down-Regulation des HLA-DR-Antigens oder um einen Verlust der HLA-DR-positiven kornealen Langerhans-Zellen (LZ) handelt. Material und Methode: Mit Hilfe einer fluoreszierenden Immunhistochemie wurden korneale Langerhans-Zellen in situ dargestellt, und die verwendeten Organkulturmedien wurden einer flußzytometrischen Analyse auf HLA-DR-positive LZ unterzogen. Ergebnisse: Nach einer 14 tägigen Lagerzeit waren alle gelagerten Korneae HLA-DR-negativ, und das Antigen ließ sich am Ende der Lagerzeit im Kulturmedium nachweisen. Schlußfolgerung: Die flußzytometrische Darstellung zeigte, daß es während der Organkulturlagerung tatsächlich zu einem Verlust der HLA-DR-positiven Zellen und nicht nur zu einem Verlust der Antigenpräsentation kommt.
    Notes: Background: Corneal HLA-DR antigens are going to be lost during organ culture storage. This study investigated if this phenomenon is based on down-regulation of the HLA-DR antigen, or on a loss of the HLA-DR-positive corneal Langerhans cells (LCs). Material and methods: Corneal LCs were stained in situ by the method of fluorescence-associated immunohistochemistry, and the organ culture mediums underwent flow cytometric analysis for HLA-DR-positive corneal LC at the end of the storage period. Results: All stored corneas were negative for HLA-DR after 14 days and HLA-DR antigens could be detected in culture medium at the end of the storage time. Conclusion: Flow cytometry showed that organ culture storage leads to loss of HLA-DR-positive cells and not only to a loss of antigen presentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003470050188
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  • 5
    Electronic Resource
    Electronic Resource
    Microwave digestion methods for the determination of trace elements in brain and liver samples by inductively coupled plasma mass spectrometry (1996)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 355 (1996), S. 120-128 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two microwave digestion systems (open-focused and closed-pressurized) were tested for the mineralization of human brain and bovine liver (NIST SRM 1577a) as dissolution steps prior to the determination of 16 trace elements (Bi, Cd, Co, Cs, Cu, Fe, Hg, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) by inductively coupled plasma mass spectrometry (ICP-MS). Digestion parameters (mass of sample, digestion mixture, and power/time steps) were optimized using temperature and pressure sensors. Digestions with the open-focused microwave system require larger volumes of conc. HNO3 and 30% H2O2 than digestions with the closed-pressurized system. Both systems produce correct results for the bovine liver samples. The concentrations obtained for the digests of the open-focused system tend to be less precise than the concentrations from the “closed-pressurized” digests. Because the “open-focused” digests must be diluted to 50 mL to bring the acid concentration to 0.7–2.0 mol/L required by the ICP-MS (closed-pressurized digests need to be diluted to only 20 mL), the detection limits for the system with the open-focused digestion are higher than for the system with the closed-pressurized digestor. The open-focused digestor cannot handle more than 150 mg brain tissue, whereas the closed-pressurized system can mineralize 470 mg. The latter method gave better results with brain tissue than the open-focused system. The preparation of brain tissue as reference material for the determination of trace elements in brain samples is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0021663550120
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