Irinotecan in patients with relapsed or cisplatin-refractory germ cell cancer: a phase II study of the German Testicular Cancer Study Group

Despite generally high cure rates in patients with metastatic germ cell cancer, patients with progressive disease on first-line cisplatin-based chemotherapy or with relapsed disease following high-dose salvage therapy exhibit a very poor prognosis. Irinotecan has shown antitumour activity in human testicular tumour xenografts in nude mice. We have performed a phase II study examining the single agent activity of irinotecan in patients with metastatic relapsed or cisplatin-refractory germ cell cancer. Refractory disease was defined as progression or relapse within 4 weeks after cisplatin-based chemotherapy or relapse after salvage high-dose chemotherapy with autologous stem cell support. Irinotecan was administered at a dose of 300 (−350) mg m−2 every 3 weeks. Response was evaluated every 4 weeks. Fifteen patients have been enrolled. Median age was 35 (19–53) years. Primary tumour localisation was gonadal/mediastinal in 12/3 patients. Patients had been pretreated with a median of six (4–12) cisplatin-containing cycles and 13 out of 15 patients had previously failed high-dose chemotherapy with blood stem cell support. Median number of irinotecan applications was two (1–3). Fourteen patients are assessable for response and all for toxicity. In one patient, no adequate response evaluation was performed. Toxicity was generally acceptable and consisted mainly of haematological side effects with common toxicity criteria 3° anaemia (two patients), common toxicity criteria 3° leukocytopenia (one patient) and common toxicity criteria 3° thrombocytopenia (three patients). Common toxicity criteria 3/4° non-haematological toxicity occurred in five patients (33%): 1×diarrhoea, 2×alopecia, 1×fever and in one patient worsening of pre-existing peripheral polyneuropathy from 1° to 4°. No response was observed to irinotecan therapy. Currently, 13 patients have died of the disease and two patients are alive with the disease. The patients included in our study exhibit similar prognostic characteristics as patients treated in previous trials evaluating new drugs in this setting. Irinotecan at a dose of 300–350 mg m−2 every 3 weeks appears to have no antitumour activity in patients with cisplatin-refractory germ cell cancer and, thus, further investigation in this disease is not justified

Importance and controls of anaerobic ammonium oxidation influenced by riverbed geology

Rivers are an important global sink for excess bioavailable nitrogen: they convert approximately 40% of terrestrial N runoff per year (∼47 Tg) to biologically unavailable N 2 gas and return it to the atmosphere. At present, riverine N 2 production is conceptualized and modelled as denitrification. Anaerobic ammonium oxidation, known as anammox, is an alternative pathway of N 2 production important in marine environments, but its contribution to riverine N 2 production is not well understood. Here we use in situ and laboratory measurements of anammox activity using 15 N tracers and molecular analyses of microbial communities to evaluate anammox in clay-, sand-and chalk-dominated river beds in the Hampshire Avon catchment, UK during summer 2013. Abundance of the hzo gene, which encodes an enzyme central to anammox metabolism, varied across the contrasting geologies. Anammox rates were similar across geologies but contributed different proportions of N 2 production because of variation in denitrification rates. In spite of requiring anoxic conditions, anammox, most likely coupled to partial nitrification, contributed up to 58% of in situ N 2 production in oxic, permeable riverbeds. In contrast, denitrification dominated in low-permeability clay-bed rivers, where anammox contributes roughly 7% to the production of N 2 gas. We conclude that anammox can represent an important nitrogen loss pathway in permeable river sediments

Frostmusterbedingte Seen der Polygonalen Tundra und ihre Funktion als Quellen atmosphärischen Methans

Frostmusterbedingte Seen sind ein wesentlicher Bestandteil der Polygonalen Tundren. Über ihre Bedeutung für die Methanemissionen dieser Gebiete ist bis heute nichts bekannt. Es gibt nur wenige Untersuchungen über ihre Funktion als natürliche Methanquellen. Genaue Angaben über ihre Verbreitung innerhalb der Polygonalen Tundren existieren nicht.Das Ziel der vorliegenden Arbeit war die Evaluierung der Methanflüsse frostmusterbedingter Seen anhand einer Beispielregion der Polygonalen Tundra (Insel Samoylov) im Gebiet des nordsibirischen Lena-Deltas. Die Geländearbeiten wurden während der durch das AWI Potsdam organisierten Expedition Lena-Delta Neusibirische Inseln 2002 vom 23. Juni bis zum 11. September 2002 durchgeführt.Die zentrale Aufgabe der Arbeit war die kontinuierliche Messung der Methanemissionen frostmusterbedingter Seen der Insel Samoylov während der Vegetationsperiode des Jahres 2002 mittels eigens hierfür konstruierter Emissionsmesshauben sowie Analyseverfahren der Gaschromatographie. Untersucht wurde zum einen die pflanzenvermittelte Methanemission durch emerse Vegetation im Flachwasserbereich und zum anderen die Methandiffusion an der Grenze Wasser-Luft sowie die Freisetzung methanhaltiger Gasblasen im tieferen Freiwasserbereich. Für die Evaluierung essentieller biotischer bzw. abiotischer Steuergrößen gewässergebundener Methanemissionen wurden parallel diverse Standortfaktoren untersucht. Für die Untersuchung der räumlichen Verbreitung frostmusterbedingter Seen im Untersuchungsgebiet wurden hochauflösende Satellitendaten ausgewertet

Patterned ground lakes and their function as sources of atmospheric methane

Lakes are important sources of atmospheric methane (CHANTON et al. 1989; THEBRATH1 991; MICHMERHUIZE&N STRIEGL1 996; SEMILETOV et al., 1996; PHELPS et al. 1998; DUCHEMIN et al. 1999; MAKHOV et al. 1999; HUTTUNEN et al. 2001). Permafrost landscapes of the Lena-Delta are often covered by polygonal tundra and patterned ground lakes, respectively. Up to now little is known about the contribution of those small but widespread lakes regarding their function as sources of atmospheric methane. Thus, surveying patterned ground lakes is a necessary part of investigations for estimating both global and local methane fluxes

Nitrogen transforming community in a horizontal subsurface-flow constructed wetland

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Quantifying Potential N Turnover Rates in Hypersaline Microbial Mats by Using N-15 Tracer Techniques

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