| 1. |
- Farman, H. H., et al.
(författare)
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Female mice lacking estrogen receptor-α in hypothalamic proopiomelanocortin (POMC) neurons display enhanced estrogenic response on cortical bone mass
- 2016
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 157:8, s. 3242-3252
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor(ER)α.CentralERα exertsaninhibitoryroleonbonemass.ERα ishighlyexpressedinthearcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα -/- ). Female POMC-ERα -/- and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα -/- mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P < .01) and mechanical strength (+193 ± 38%, P < .01). To test whether ERα in VMN is involved in the regulation of bone mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERaα-mediated effects in bone determines cortical bone mass in female mice.
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| 2. |
- Tjernström, Michael, et al.
(författare)
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The Arctic Summer Cloud Ocean Study (ASCOS) : overview and experimental design
- 2014
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:6, s. 2823-2869
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Tidskriftsartikel (refereegranskat)abstract
- The climate in the Arctic is changing faster than anywhere else on earth. Poorly understood feedback processes relating to Arctic clouds and aerosol-cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in situ in this difficult-to-reach region with logistically demanding environmental conditions. The Arctic Summer Cloud Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007-2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait: two in open water and two in the marginal ice zone. After traversing the pack ice northward, an ice camp was set up on 12 August at 87 degrees 21' N, 01 degrees 29' W and remained in operation through 1 September, drifting with the ice. During this time, extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first-ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggests the possibility of primary marine organically derived cloud condensation nuclei in Arctic stratocumulus clouds. Direct observations of surface fluxes of aerosols could, however, not explain observed variability in aerosol concentrations, and the balance between local and remote aerosols sources remains open. Lack of cloud condensation nuclei (CCN) was at times a controlling factor in low-level cloud formation, and hence for the impact of clouds on the surface energy budget. ASCOS provided detailed measurements of the surface energy balance from late summer melt into the initial autumn freeze-up, and documented the effects of clouds and storms on the surface energy balance during this transition. In addition to such process-level studies, the unique, independent ASCOS data set can and is being used for validation of satellite retrievals, operational models, and reanalysis data sets.
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| 3. |
- Hardell, L, et al.
(författare)
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Testicular cancer and occupational exposure to polyvinyl chloride plastics: A case-control study
- 2004
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 109:3, s. 425-429
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to polyvinyl chloride. (PVC) plastics as a risk factor for testicular cancer was investigated. In total, 981 cases who were 20-75 years old and had reported to the Swedish Cancer Registry during 1993-1997 were included. One matched control from the population registry was used. Exposure was assessed by a questionnaire that was supplemented over the phone. Furthermore, an occupational hygienist qualified all exposures. In all, 791 matched pairs completed the questionnaire. Overall exposure to PVC plastics gave the odds ratio (OR)= 1.35, 95% confidence interval (Cl)= 1.06-1.71, increasing with > 10 year latency period to OR= 1.45, 95% Cl = 1.06-1.98. No dose-response relationships were found but rather an inverse relationship with the highest odds ratios in the lowest exposure category. In conclusion, no clear association with testicular cancer and exposure to PVC could be found in our study in contrast to a previous observation.
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