Cell-cycle progression of rat thymocytes stimulated with concanavalin A and interleukin 2 was monitored at 12-h intervals by pulse labeling aliquots of the cell culture with [3H]thymidine, by measuring cellular DNA and protein content and by counting the number of cells in the cultures. The cell cycle was completed after 96 h of culture with the S phase peaking at 48 h. Early events in thymocyte activation were enhanced phosphatidylinositol turnover and the induction of ornithine decarboxylase. Concomitant changes were observed in the rates of DNA synthesis and glycolysis accompanied by a 20-fold increase in glucose uptake 48 h after stimulation. However, the maximal increment in the glycolytic rate preceded that of DNA synthesis by 12 h. Apart from the quantitative changes which occurred during the cell-cycle progression, there was also a change from partial aerobic glucose degradation to COz (26%) to almost complete anaerobic conversion of glucose to lactate (85%) and less than 3% to COz. Glycolytic enzyme levels increased fourfold to tenfold and reached their maxima 48 h after mitogenic stimulation. Maximal increments of glycolytic enzyme activities preceded or coincided with the maximal increments of the glycolytic rate. Actinomycin D (1.5 ng/ml) completely inhibited DNA and RNA synthesis but did not show any inhibitory effect either on glycolytic enzyme induction or on enhanced glycolysis. During mitosis and return of the cells to the non-proliferative state, all of the enhanced metabolic rates returned to their initial levels and the elevated enzyme activities were decreased also. The marked changes of metabolic rates and enzyme activities observed at the various phases of the cell cycle suggest that these biochemical events may also serve as suitable parameters for evaluating the response of lymphocytes towards mitogens and lymphokines.Activation of quiescent rat thymocytes by polyclonal mitogens such as concanavalin A (ConA) involves a complex cascade of biochemical reactions which result in promoting cell-cycle entry and expression of receptors for interleukin 2 (11-2). On addition of 11-2, progression through GI to DNA synthesis in S phase and final proliferation of thymocytes occurs. Recent studies of lymphocyte activation have implicated an increased conversion of phosphatidylinositol into inositol trisphosphate and diacylglycerol already as an early event [l -71. Subsequently the phospholipid/Ca2 '-dependent protein kinase C [8] is activated and intracellular Ca2+ concentration as well as pH [9 -171 increases. Cell-cycle advancement from the resting Go to the activated G I stage also inCorrespondence to K. Brand,

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Conceptualising heritage as a contested process of past-based meaning production in the present, this paper analyses the ongoing dispute over street names in Berlin's Afrikanisches Viertel. In 1899, Berlin named two of its newly-built streets Togo Street and Cameroon Street. Togo and Cameroon had been proclaimed the first German colonies in 1884. By 1958, 22 Berlin streets had been named after African regions that had been colonised by the German Empire or after German colonial protagonists. In 2004, several NGOs called for the renaming of some of these streets, igniting a fierce dispute over the heritage status of the German colonial past. Drawing on guided interviews and document analyses, we analyse this debate on three levels, showing how the NGOs and their claims have been marginalised on each level. While the level of agency can be traced back to the different positioning of the actors in the political field, the levels of temporality and spatiality belong to the realm of ideas about the world and one's place in it. By exploring the authoritative power of traditional notions of permanence, and of place and space, this paper seeks to bring temporality and spatiality into the focus of those studying heritage-making practices.

verzeichnet diese Publikation in der Deutschen Nationalbibliografi e; detaillierte bibliografi sche Daten sind im Internet über abrufbar.Dieses Werk ist urheberrechtlich geschützt. Die dadurch begründeten Rechte, insbesondere die der Übersetzung, des Nachdruckes, des Vortrags, der Entnahme von Abbildungen und Tabellen, der Funksendung, der Mikroverfi lmung oder der Vervielfältigung auf anderen Wegen und der Speicherung in Datenverarbeitungsanlagen, bleiben, auch bei nur auszugsweiser Verwertung, vorbehalten. Eine Vervielfältigung dieses Werkes oder von Teilen dieses Werkes ist auch im Einzelfall nur in den Grenzen der gesetzlichen Bestimmungen des Urheberrechtsgesetzes der Bundesrepublik Deutschland vom 9. September 1965 in der jeweils geltenden Fassung zulässig. Sie ist grundsätzlich vergütungspfl ichtig. Zuwiderhandlungen unterliegen den Strafbestimmungen des Urheberrechtsgesetzes.

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