Characteristics of out-of-field teaching: Teacher beliefs and competencies

International audienceIn recent years, some efforts have been made to consolidate out-of-field-teaching as research field in mathematics education. Taking teachers' professional knowledge as reference frame, out-of-field-teachers seem less qualified regarding CK and PCK in mathematics than teachers that were especially trained to teach their subject. In this paper, we approach the phenomenon of out-of-field-teaching by focusing on both teachers' beliefs and competencies while the latter is operationalized as skills in designing mathematical tasks for written exams. Data was collected throughout a qualification program particularly focusing on out-of-field-teachers' domain-specific professional knowledge. We discuss in detail design aspects of our ongoing research and give first insights into the changes of out-of-field-teachers' beliefs reflecting their professional development in the course of the qualification program

Age dependent secretion of LH and ACTH in healthy persons and patients with erectile dysfunction

Bei gesunden Probanden finden sich keine altersabhängigen Veränderungen im Sekretionsmuster von LH und ACTH. Der für Patienten mit erektiler Dysfunktion signifikante Altersanstieg von LH untermauert die Bedeutung der Leydigzelldegeneration für dieses Krankheitsbild. Jedoch konnte zwischen dem Testosteronabfall der Normalgruppe und den ED-Patienten kein signifikanter Unterschied gefunden werden. Dies spricht für Kompensationsmechanismen bei der Patientengruppe und damit nicht primär für einen Testosteron-Ersatz. Die Sekretion von Nebenierenandrogenen erscheint für die ED ohne Bedeutung, wobei keine Hinweise für eine Regulation über ACTH gefunden werden konnten

Age dependent secretion of LH and ACTH in healthy persons and patients with erectile dysfunction

Bei gesunden Probanden finden sich keine altersabhängigen Veränderungen im Sekretionsmuster von LH und ACTH. Der für Patienten mit erektiler Dysfunktion signifikante Altersanstieg von LH untermauert die Bedeutung der Leydigzelldegeneration für dieses Krankheitsbild. Jedoch konnte zwischen dem Testosteronabfall der Normalgruppe und den ED-Patienten kein signifikanter Unterschied gefunden werden. Dies spricht für Kompensationsmechanismen bei der Patientengruppe und damit nicht primär für einen Testosteron-Ersatz. Die Sekretion von Nebenierenandrogenen erscheint für die ED ohne Bedeutung, wobei keine Hinweise für eine Regulation über ACTH gefunden werden konnten

Archives of Toxicology / Mesenchyme-derived factors enhance preneoplastic growth by non-genotoxic carcinogens in rat liver

Many frequently prescribed drugs are non-genotoxic carcinogens (NGC) in rodent liver. Their mode of action and health risks for humans remain to be elucidated. Here, we investigated the impact of two model NGC, the anti-epileptic drug phenobarbital (PB) and the contraceptive cyproterone acetate (CPA), on intrahepatic epithelialmesenchymal crosstalk and on growth of first stages of hepatocarcinogenesis. Unaltered hepatocytes (HC) and preneoplastic HC (HCPREN) were isolated from rat liver for primary culture. DNA replication of HC and HCPREN was increased by in vitro treatment with 10 M CPA, but not 1 mM PB. Next, mesenchymal cells (MC) obtained from liver of rats treated with either PB (50 mg/kg bw/day) or CPA (100 mg/kg bw/day), were cultured. Supernatants from both types of MC raised DNA synthesis of HC and HCPREN. This indicates that PB induces replication of HC and HCPREN only indirectly, via growth factors secreted by MC. CPA, however, acts on HC and HCPREN directly as well as indirectly via mesenchymal factors. Transcriptomics and bio-informatics revealed that PB and CPA induce extensive changes in the expression profile of MC affecting many growth factors and pathways. MC from PB-treated rats produced and secreted enhanced levels of HBEGF and GDF15, factors found to suppress apoptosis and/or induce DNA synthesis in cultured HC and HCPREN. MC from CPA-treated animals showed enhanced expression and secretion of HGF, which strongly raised DNA replication of HC and HCPREN. In conclusion, our findings reveal profound effects of two prototypical NGC on the hepatic mesenchyme. The resulting release of factors, which suppress apoptosis and/or enhance cell replication preferentially in cancer prestages, appears to be crucial for tumor promotion by NGC in the liver.(VLID)357486