Preliminary study of plasma vascular endothelial growth factor (VEGF) during low- and high-dose radiation therapy of dogs with spontaneous tumors

High plasma vascular endothelial growth factor (VEGF) concentrations are associated with radiation resistance and poor prognosis. After an exposure to ionizing radiation in cell culture an early phase and a late phase of increased VEGF have been documented. The activation was dependent on the radiation dose. Therefore, the purpose of this study was to measure baseline plasma VEGF and changes in VEGF over the course of fractionated radiation therapy in dogs with spontaneous tumors. Dogs with tumors had a significantly higher pretreatment plasma VEGF than did dogs without tumors. Immediately after irradiation no increased plasma VEGF was observed. Over the course of radiation therapy there was an increased plasma VEGF in dogs treated with low doses per fraction/high total dose, whereas plasma VEGF remained stable in dogs irradiated with high doses per fraction/low total dose. The regulatory mechanisms are very complex, and therefore the value of plasma VEGF measurements as an indirect marker of angiogenesis induced by radiotherapy is limited.     

Vegetational changes in the Galápagos Islands during the period 1966–1973

Analysis of 12 permanent sample plots established in the Galápagos showed that introduced mammals have had a destructive influence on the vegetation; closed forest and scrub have been changed into open vegetation. The plots provide information on the regeneration ability of various types of vegetation. Scalesia forest, dominated by the endemic Scalesia pedunculata Hook. f., might under certain circumstances regenerate rapidly. Miconia scrub, dominated by the endemic Miconia robinsoniana Cogn., regenerates slowly and is consequently more vulnerable to the activities of man and introduced mammals. Arid zone vegetation, characterised especially by endemic species of Opuntia, is able to regenerate, but it is still too early to estimate how the regeneration will proceed. The suggested conservation measures include a continuation of the programme for elimination or control of introduced mammals, and a stronger control with the National Park areas on inhabited islands. Financial support is needed for the Galápagos National Park Service and the Charles Darwin Research Station to continue and enlarge the activities necessary to preserve the unique wildlife of the Galápagos Islands.     

Die Wirkung neuartiger insektizider Mittel auf Regenwürmer

Ohne Zusammenfassung     

Der vegetabilische und animalische Nahrungsbereich des Hamsters (Cricetus cricetus L.)

Ohne Zusammenfassung     

Die Neugestaltung der Forstwissenschaft in der Ostmark im Geiste des Nationalsozialismus

Ohne Zusammenfassung