Comparison of the toxicokinetics of daidzein and bisphenol A in pregnant and non-pregnant DA/Han rats

Potentially adverse human and environmental effects due to hormone mimicry of environmental estrogens are a matter of current concern. Environmental estrogens belong to the socalled endocrine active compounds (EAC) and may alter signalling processes of the endocrine system leading to a broad range of effects during fetal and postnatal development, puberty, adulthood, and aging. A number of synthetic chemicals as well as several plant-derived compounds, socalled phytoestrogens, are known to have weak estrogenic activity. The present study is part of the risk assessment of the weak environmental estrogens daidzein and bisphenol A. The isoflavone daidzein is an important phytoestrogen with respect to dietary exposure (soy beans and soy products) whereas bisphenol A is an industrial chemical that occurs at much lower concentrations as a contaminant in food. The toxicokinetics of these compounds in female pregnant and non-pregnant DA/Han rats after single intravenous application were compared by the use of the Mann-Whitney- U-statistic. --Bisphenol A,daidzein,xenoestrogens,phytoestrogens,endocrine active compounds,Mann-Whitney-U-test

Cellular and extracellular siderophores of Aspergillus nidulans and Penicillium chrysogenum

Aspergillus nidulans and Penicillium chrysogenum produce specific cellular siderophores in addition to the well-known siderophores of the culture medium. Since this was found previously in Neurospora crassa, it is probably generally true for filamentous ascomycetes. The cellular siderophore of A. nidulans is ferricrocin; that of P. chrysogenum is ferrichrome. A. nidulans also contains triacetylfusigen, a siderophore without apparent biological activity. Conidia of both species lose siderophores at high salt concentrations and become siderophore dependent. This has also been found in N. crassa, where lowering of the water activity has been shown to be the causal factor. We used an assay procedure based on this dependency to reexamine the extracellular siderophores of these species. During rapid mycelial growth, both A. nidulans and P. chrysogenum produced two highly active, unidentified siderophores which were later replaced by a less active or inactive product--coprogen in the case of P. chrysogenum and triacetylfusigen in the case of A. nidulans. N. crassa secreted coprogen only. Fungal siderophore metabolism is varied and complex

Trade and Welfare Impacts of Partial Liberalization of U.S. Sugar TRQs: The Application of a PE/GE Modeling Approach

The sugar sector is one of the most heavily protected commodities in agriculture using a system of tariff rate quotas (TRQs) with a complex set of administration procedures. General equilibrium models are not suitable to analyze trade liberalization scenarios that involve numerous tariff-rate quotas across narrowly defined product lines. We use the Rutherford/Grant/Hertel modeling approach by embedding a detailed, partial equilibrium (PE) model into a standard, global general equilibrium (GE) framework. We use this PE/GE model to compare trade and welfare outcomes of two liberalization scenarios: Increasing quota levels by 25% and cutting over tariffs by 50%, versus increasing quota levels by 50% and cutting over-quota tariffs by 25%. We find that lowering over-quota tariffs relatively more has more positive welfare effects than increasing quota levels relatively more.International Relations/Trade,

Estimation of the Mean AUC of the Xenoestrogens Daidzein, Bisphenol A, and p-tert-Octylphenol

Potentially adverse human and environmental effects due to hormone mimicry of environmental estrogens are a matter of current concern. Environmental estrogens belong to the so-called endocrine active compounds (EAC), which alter signalling processes of the endocrine system leading to a broad range of effects during foetal and postnatal development, puberty, adulthood, and aging. A number of synthetic chemicals as well as several plant-derived compounds, so-called phytoestrogens, are known to have weak estrogenic activity. The present study is part of the risk assessment of the weak environmental estrogens daidzein, p-tert-octylphenol, and bisphenol A. The isoflavone daidzein is an important phytoestrogen with respect to dietary exposure (soy beans and soy products). p-tert-Octylphenol and bisphenol A are industrial chemicals. The toxicokinetics and the bioavailability of these three substances in female DA/Han rats after oral and single intravenous application were investigated by the use of population models accounting for the differences in the individual metabolism. Furthermore, populations of pregnant and non-pregnant rats are compared

From Great Depression to Great Credit Crisis: Similarities, Differences and Lessons

The Great Depression of the Thirties and the Great Credit Crisis of the "Noughties had similar causes but elicited strikingly different policy responses. It may still be too early to assess the effectiveness of current policy responses, but it is possible to analyze monetary and fiscal policies in the 1930s as a "natural experiment" or "counterfactual" capable of shedding light on the impact of recent policies. We employ vector autoregressions, instrumental variables, and qualitative evidence for a panel of 27 countries in the period 1925-1939. The results suggest that monetary and fiscal stimulus was effective – that where it did not make a difference it was not tried. The results also shed light on the debate over fiscal multipliers in episodes of financial crisis. They are consistent with multipliers at the higher end of those estimated in the recent literature, consistent with the idea that the impact of fiscal stimulus will be greater when banking system are dysfunctional and monetary policy is constrained by the zero bound.

RCS043938-2904.9: A New Rich Cluster of Galaxies at z=0.951

We present deep I, J_s, K_s imaging and optical spectroscopy of the newly discovered Red-Sequence Cluster Survey cluster RCS043938-2904.9. This cluster, drawn from an extensive preliminary list, was selected for detailed study on the basis of its apparent optical richness. Spectroscopy of 11 members places the cluster at z=0.951 +- 0.006, and confirms the photometric redshift estimate from the (R-z) color-magnitude diagram. Analysis of the infrared imaging data demonstrates that the cluster is extremely rich, with excess counts in the Ks-band exceeding the expected background counts by 9 sigma. The properties of the galaxies in RCS043938-2904.9 are consistent with those seen in other clusters at similar redshifts. Specifically, the red-sequence color, slope and scatter, and the size-magnitude relation of these galaxies are all consistent with that seen in the few other high redshift clusters known, and indeed are consistent with appropriately evolved properties of local cluster galaxies. The apparent consistency of these systems implies that the rich, high-redshift RCS clusters are directly comparable to the few other systems known at z ~ 1, most of which have been selected on the basis of X-ray emission.Comment: 12 pages, 1 color figure. Accepted for publication on The ApJ Letter

Novi aspekti u klasifikaciji kancerogena

The existing systems of classification of carcinogens should include a distinction between genotoxic and non-genotoxic chemicals. For non-genotoxic chemicals, permissible exposure levels can be derived at which no relevant human cancer risks are anticipated. While genotoxic carcinogens can induce chromosomal effects without mutagenic action, non-DNA-reactive genotoxins affecting topoisomerase or the spindle, or those having an exclusively aneugenic effect can be carcinogenic only at high, toxic doses. Specific mechanisms of clastogenicity and processes of carcinogenesis based on reactive oxygen have practical thresholds. Since reactive oxygen species (ROS) are generally genotoxic, the question is whether chemicals that increase ROS production will add to endogenously produced background levels and lead to nonlinear dose-effect relationships. Taking into account the presence of endogenous carcinogens, it is now becoming evident that carcinogenic risk extrapolation to low doses must be considered according to the mode of action.U postojećem sistemu klasifikacije kancerogenih tvari utvrđena je razlika između genotoksičnih i negenotoksičnih kemikalija. Za negenotoksične kemikallije mogu se izvesti pretpostavljeni stupnjevi izlaganja kod kojih ne postoji značajan rizik od pojave raka kod ljudi. Za genotoksične kancerogene mogući su na primjer inducirani kromosomski efekti bez početka procesa mutageneze, dok genotoksični toksini koji se ne vežu za DNA-molekulu, a djeluju na topoizomere ili diobeno vreteno ili su aneugeni, izazivaju kancerogene efekte jedino u visokim, toksičnim dozama. Za specifične mehanizme klastrogenog djelovanja i procesa kancerogeneze koji se baziraju na reaktivnom kisiku postoji prag početka procesa. Kako su vrste kemikalija reaktivne na kisik (ROS) u načelu genotoksične, pojavljuju se pitanja da li kemikalije koje povećavaju produkciju ROS-vrsta treba pridodati endogenim kancerogenima pozadinskog stupnja koji uzrokuju nelinearni odnos doze i učinka. Uzimajući u obzir rasprave o prisutnosti endogenih kancerogena, sada postaje jasno da se kancerogeni rizik od niskih doza mora uzeti u obzir sukladno načinu njihova djelovanja