Entity

Time filter

Source Type


Crossley D.A.,University of North Texas | Wearing O.H.,University of Manchester | Platzack B.,Swedish Toxicology Science Research Center Swetox | Hartzler L.K.,Wright State University | Hicks J.W.,University of California at Irvine
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology | Year: 2015

Acute and chronic changes in ambient temperature alter several aspects of reptilian physiology. We investigated the effects of each type of temperature change on reptilian cardiovascular regulation in red-eared slider turtles (Trachemys scripta), a species known to experience marked seasonal changes in ambient temperature. Turtles were instrumented with occlusive catheters in the femoral artery and vein. Following an acclimation period of 10 days at 13 °C (131), cardiovascular responses to adrenaline, and the cardiac limb of the baroreflex were quantified. Ambient temperature was then reduced 1 °C day−1 until 3 °C was reached (31). Turtles were maintained at this temperature for 1-week before cardiovascular responses were reassessed. Turtles were then gradually (1 °C day−1) returned to an ambient temperature of 13 °C, (132). After a 1-week re-acclimation period, cardiovascular responses were again determined. Finally, 1-week post-pharmacological manipulation of turtles in the 132 treatment, ambient temperature was reduced to 3 °C over 24 h (32), and cardiovascular responses were again assessed. Temperature reduction from 131 to 31 decreased mean arterial blood pressure (Pm) and heart rate (fH) by ~38 and ~63 %, respectively. Acute temperature reduction, from 132 to 32, decreased fH similarly, ~66 %; however, while Pm decreased ~28 %, this was not significantly different than Pm at 132. The adrenaline injections increased fH ranging from 90 to 170 % at 13 °C which was a greater change than that observed at 3 °C ranging from a 40 to 70 % increase. The increase in Pm at the lowest dose of adrenaline did not differ across the temperature treatment groups. The operational point (set-point) Pm of the baroreflex was decreased similarly by both methods of temperature reduction (31 or 32). Further, a hypertensive cardiac baroreflex was absent in the majority of the animals studied independent of temperature. Baroreflex gain and normalized gain based on individual estimates of the relationship were decreased by temperature reduction similarly. Collectively, the data suggest that red-eared slider turtles modulate (down-regulate) some cardiovascular control mechanisms during reduced ambient temperature. © Springer-Verlag Berlin Heidelberg 2015. Source


Gocht T.,University of Tubingen | Berggren E.,EU Joint Research Centre | Ahr H.J.,Bayer AG | Cotgreave I.,Swedish Toxicology Science Research Center Swetox | And 14 more authors.
Altex | Year: 2015

SEURAT-1 is a European public-private research consortium that is working towards animal-free testing of chemical compounds and the highest level of consumer protection. A research strategy was formulated based on the guiding principle to adopt a toxicological mode-of-action framework to describe how any substance may adversely affect human health. The proof of the initiative will be in demonstrating the applicability of the concepts on which SEURAT-1 is built on three levels: (i) Theoretical prototypes for adverse outcome pathways are formulated based on knowledge already available in the scientific literature on investigating the toxicological modes-of-action leading to adverse outcomes (addressing mainly liver toxicity); (ii) adverse outcome pathway descriptions are used as a guide for the formulation of case studies to further elucidate the theoretical model and to develop integrated testing strategies for the prediction of certain toxicological effects (i.e., those related to the adverse outcome pathway descriptions); (iii) further case studies target the application of knowledge gained within SEURAT-1 in the context of safety assessment. The ultimate goal would be to perform ab initio predictions based on a complete understanding of toxicological mechanisms. In the near-term, it is more realistic that data from innovative testing methods will support read-across arguments. Both scenarios are addressed with case studies for improved safety assessment. A conceptual framework for a rational integrated assessment strategy emerged from designing the case studies and is discussed in the context of international developments focusing on alternative approaches for evaluating chemicals using the new 21st century tools for toxicity testing. Source


Lindsjo J.,Swedish University of Agricultural Sciences | Fahlman A.,Swedish University of Agricultural Sciences | Tornqvist E.,Swedish Toxicology Science Research Center Swetox | Tornqvist E.,Karolinska Institutet
Journal of Wildlife Diseases | Year: 2016

The concept of the 3Rs (replacement, reduction, and refinement) was originally developed for improving laboratory animal welfare and is well known in biomedical and toxicologic research. The 3Rs have so far gained little attention in wildlife research, and there could be several reasons for this. First, researchers may prioritize the welfare of populations and ecosystems over the welfare of individual animals. The effects of research on individual animals can, however, impact welfare and research quality at group and population levels. Second, researchers may find it difficult to apply the 3Rs to studies of free-living wildlife because of the differences between laboratory and wild animals, species, research environment, and purpose and design of the studies. There are, however, several areas where it is possible to transfer the 3R principles to wildlife research, including replacement with noninvasive research techniques, reduction with optimized experimental design, and refinement with better methods of capture, anesthesia, and handling. Third, researchers may not have been trained in applying the 3Rs in wildlife research. This training is needed since ethics committees, employers, journal publishers, and funding agencies increasingly require researchers to consider the welfare implications of their research. In this paper, we compare the principles of the 3Rs in various research areas to better understand the possibilities and challenges of the 3Rs in wildlife research. We emphasize the importance of applying the 3Rs systematically throughout the research process. Based on experiences from laboratory research, we suggest three key factors to enhance implementation of the 3Rs in wildlife research: 1) organizational structure and management, 2) 3R awareness, and 3) research innovation, validation, and implementation. Finally, we encourage an interdisciplinary approach to incorporate the 3R principles in wildlife research. For improved animal welfare and increased research quality, researchers have moral obligations to include the 3Rs into all research areas, including wildlife research. © Wildlife Disease Association 2016. Source


Dahlberg A.-K.,University of Stockholm | Lindberg Chen V.,University of Stockholm | Larsson K.,Linnaeus University | Bergman A.,University of Stockholm | And 2 more authors.
Chemosphere | Year: 2016

Long-tailed ducks (Clangula hyemalis) that breed in northern Europe and western Siberia and commonly winter in the Baltic Sea, are threatened by a significant population decrease. The ducks are, by primarily feeding on Baltic blue mussels (Mytilus trossulus × Mytilus edulis) while wintering in the Baltic Sea, potentially subjected to high levels of toxic hydroxylated polybrominated diphenyl ethers (OH-PBDEs). To assess long-tailed ducks exposure to polybrominated phenols (PBPs), polybrominated anisoles (PBAs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs), their methylated counterparts (MeO-PBDEs) and polybrominated diphenyl ethers (PBDEs), livers of ten long-tailed ducks wintering in the Baltic Sea were analysed. Pattern and levels of analytes in long-tailed ducks (liver) and blue mussels sampled in March and May at nine sites in the Baltic Sea were compared. The geometric mean concentration (ng/g l.w.) in livers of long-tailed ducks and Baltic blue mussels were: σ2PBPs: 0.57 and 48; σ2PBAs: 0.83 and 11; σ7OH-PBDEs: 6.1 and 45; σ7MeO-PBDEs: 3.8 and 69; σ7PBDEs: 8.0 and 7.2, respectively. Based on an estimated daily intake of 450 g fresh blue mussel meat, long-tailed ducks daily dietary intake of brominated substances while foraging in the Baltic Sea in March-May was estimated to; 390 ng σ2PBPs, 90 ng σ2PBAs, 370 ng σ7OH-PBDEs, 590 ng σ7MeO-PBDEs and 59 ng σ7PBDEs. The low levels of PBPs, PBAs, OH-PBDEs and MeO-PBDEs in the long-tailed duck livers compared to blue mussel, despite a continuous daily intake, suggest that these compounds are poorly retained in long-tailed ducks. © 2015 The Authors. Source


Fang J.,University of Stockholm | Fang J.,Swedish Museum of Natural History | Nyberg E.,Swedish Museum of Natural History | Winnberg U.,University of Stockholm | And 3 more authors.
Environmental Science and Pollution Research | Year: 2015

Persistent organic pollutants (POPs) have been of environmental and health concern for more than half a century and have their own intergovernmental regulation through the Stockholm Convention, from 2001. One major concern is the nursing child’s exposure to POPs, a concern that has led to a very large number of scientific studies on POPs in mothers’ milk. The present review is a report on the assessment on worldwide spatial distributions of POPs and of their temporal trends. The data presented herein is a compilation based on scientific publications between 1995 and 2011. It is evident that the concentrations in mothers’ milk depend on the use of pesticides and industrial chemicals defined as POPs. Polychlorinated biphenyls (PCBs) and “dioxins” are higher in the more industrialized areas, Europe and Northern America, whereas pesticides are higher in Africa and Asia and polybrominated diphenyl ethers (PBDEs) are reported in higher concentrations in the USA. POPs are consequently distributed to women in all parts of the world and are thus delivered to the nursing child. The review points out several major problems in the reporting of data, which are crucial to enable high quality comparisons. Even though the data set is large, the comparability is hampered by differences in reporting. In conclusion, much more detailed instructions are needed for reporting POPs in mothers’ milk. Temporal trend data for POPs in mothers’ milk is scarce and is of interest when studying longer time series. The only two countries with long temporal trend studies are Japan and Sweden. In most cases, the trends show decreasing concentrations of POPs in mothers’ milk. However, hexabromocyclododecane is showing increasing temporal concentration trends in both Japan and Sweden. © 2015, The Author(s). Source

Discover hidden collaborations