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The persistence of polychlorinated biphenyls (PCBs) in the environment is of considerable concern since they accumulate in human breast tissue and may stimulate the growth of estrogen-sensitive tumors. Studies have shown that EGCG from green tea can modify estrogenic activity and thus may act as a cancer chemopreventive agent. In the present study, we evaluated the individual and combined effects of PCB 102 and EGCG on cell proliferation using an estrogen-sensitive breast cancer cell line MCF-7/BOS. PCB 102 (1–10 μM) increased cell proliferation in a dose-dependent manner. Furthermore, the proliferative effects of PCB 102 were mediated by ERα and could be abrogated by the selective ERα antagonist MPP. EGCG (10–50 μM) caused a dose-dependent inhibition of PCB 102-induced cell proliferation, with nearly complete inhibition at 25 μM EGCG. The antiproliferative action of EGCG was mediated by ERβ and could be blocked by the ERβ-specific inhibitor PHTPP. In conclusion, EGCG suppressed the proliferation-stimulating activity of the environmental estrogen PCB 102 which may be helpful in the chemoprevention of breast cancer.

Well water in karst regions is particularly susceptible to contamination by various nonpoint source pollutants such as nitrate, fecal bacteria, and endocrine disrupting chemicals (EDCs). This study analyzed 40 wells in heavily farmed karst areas of northeastern Wisconsin to determine whether these and other pollutants are present, and if so, whether their presence is (1) correlated with other contaminants and (2) exhibits seasonal variation. Nitrate, bacteria, and estrogenicity (indicating the presence of EDCs) were present in at least some of well water samples collected over the course of four time periods between the summers of 2008 and 2009. Although estrogenicity was greatest during the summer months, bacterial contamination was most prevalent during snowmelt. Levels of estrogenicity present in some well water samples approached a threshold concentration that is known to exert endocrine disruption in wildlife. Strong correlations between estrogenicity and other water quality parameters were not found.

In der Lehrerbildung fand in den letzten Jahren eine Ausweitung der Schulpraxisphasen statt. Als ein zentraler Aspekt der Professionalisierung zukünftiger Lehrkräfte gilt in diesem Zusammenhang die Reflexion der eigenen Lehrerfahrungen und der eigenen Haltung als Lehrkraft. Zwar liegen mittlerweile eine Reihe konzeptioneller Vorschläge zur Ausgestaltung der universitären Begleitung dieser Phasen vor, empiriebasierte Beschreibungen der sozialen Wirklichkeit dieser Hochschulpraxis sind jedoch noch nicht im gleichen Maße vorzufinden. Eine eigene Studie widmet sich diesem Feld und fragt aus praxistheoretischer Sicht, welche spezifischen Praktiken sich in Bezug auf die Reflexion von Unterricht beschreiben lassen. Im Rahmen einer explorativen Untersuchung wird am Beispiel eines schulpraktischen Begleitseminars nachverfolgt, wie die Anforderung der Reflexion von den Akteurinnen und Akteuren gemeinsam gestaltet wird. Der vorliegende Beitrag stellt erste Befunde vor und diskutiert forschungslogische Anschlüsse.

People with amputation are at increased risk of falling compared with age-matched, nondisabled individuals. This may partly reflect amputation-related changes to minimum toe clearance (MTC) that could increase the incidence of trips and fall risk. This study determined the contribution of an active dorsiflexing prosthesis to MTC. We hypothesized that regardless of speed or incline the active dorsiflexion qualities of the ProprioFoot would significantly increase MTC and decrease the likelihood of tripping. Eight people with transtibial amputation walked on a treadmill with their current foot at two grades and three velocities, then repeated the protocol after 4 wk of accommodation with the ProprioFoot. A mixed-model, repeated-measures analysis of variance was used to compare MTC. Curves representing the likelihood of tripping were derived from the MTC distributions and a multiple regression was used to determine the relative contributions of hip, knee, and ankle angles to MTC. Regardless of condition, MTC was approximately 70% larger with the ProprioFoot (p < 0.001) and the likelihood of tripping was reduced. Regression analysis revealed that MTC with the ProprioFoot was sensitive to all three angles, with sensitivity of hip and ankle being greater. Overall, the ProprioFoot may increase user safety by decreasing the likelihood of tripping and thus the pursuant likelihood of a fall.