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  • 1
    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
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  • 2
    ISSN: 1433-0423
    Keywords: Key words Lattice dystrophy • Cornea • ; βig-h3-mutation-kerato-epitheline gene ; Schlüsselwörter Gittrige Hornhautdystrophie • ; βig-h3-Keratoepithelin-Gen-Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Hintergrund: Die gittrige Hornhautdystrophie ist eine autosomal dominant vererbte Erkrankung, verursacht durch eine Mutation des Nukleotid 417 im Kodon 124 des Keratoepithelin-Gens. Wir untersuchten, ob bei einer von uns betreuten Familie mit gittriger Hornhautdystrophie, diese Punktmutation des Nukleotids 417 nachweisbar ist. Patienten und Methoden: Bei an gittriger Hornhautdystrophie erkrankten Patienten wurden Lymphozyten extrahiert, RNA präpariert, cDNA synthetisiert und mittels Polymerase-Ketten Reaktion (PCR) amplifiziert. Die PCR-Produkte wurden sequenziert. Als Kontrolle wurde Blut eines nicht an einer Hornhautdystrophie erkrankten Patienten verwendet. Ergebnisse: Ein Austausch des sich normalerweise auf Position 417 befindlichen Guanin gegen ein Adenin konnte nachgewiesen werden. Schlußfolgerung: Auch bei unseren Patienten konnte die beschriebene Mutation von Guanin zu Adenin im Kodon 124 im Keratoepithelin-Gen gefunden werden. Damit scheint diese Punktmutation des Nukleotid 417 die für die Entwicklung der gittrigen Hornhautdystrophie verantwortliche Veränderung darzustellen.
    Notes: Background: Lattice dystrophy is an autosomal-dominantly inherited disease. A mutation of the gene coding for kerato-epitheline has been found in patients with this stromal dystrophy. In codon 124 a Guanine to Adenine mutation of the nucleotide 417 has been described. We looked for this mutation in a family with lattice dystrophy treated in our clinic. Patients and methods: Using primers specific for kerato-epitheline gene, we amplified the cDNA extracted from lymphocytes of two patients suffering from lattice dystrophy. The polymerase chain reaction (PCR) products were subcloned and sequenced. Results: Guanine to Adenine mutations, as published were detected in both of our patients at codon 124. Conclusion: We found the published mutation in both of our patients, indicating that this Guanine to Adenine exchange is pathognomonic for lattice dystrophy.
    Type of Medium: Electronic Resource
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