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- Mårtensson, Ulrika, et al.
(författare)
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Deletion of the G protein-coupled receptor 30 impairs glucose tolerance, reduces bone growth, increases blood pressure, and eliminates estradiol-stimulated insulin release in female mice.
- 2009
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 150:2, s. 687-98
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Tidskriftsartikel (refereegranskat)abstract
- In vitro studies suggest that the G protein-coupled receptor (GPR) 30 is a functional estrogen receptor. However, the physiological role of GPR30 in vivo is unknown, and it remains to be determined whether GPR30 is an estrogen receptor also in vivo. To this end, we studied the effects of disrupting the GPR30 gene in female and male mice. Female GPR30((-/-)) mice had hyperglycemia and impaired glucose tolerance, reduced body growth, increased blood pressure, and reduced serum IGF-I levels. The reduced growth correlated with a proportional decrease in skeletal development. The elevated blood pressure was associated with an increased vascular resistance manifested as an increased media to lumen ratio of the resistance arteries. The hyperglycemia and impaired glucose tolerance in vivo were associated with decreased insulin expression and release in vivo and in vitro in isolated pancreatic islets. GPR30 is expressed in islets, and GPR30 deletion abolished estradiol-stimulated insulin release both in vivo in ovariectomized adult mice and in vitro in isolated islets. Our findings show that GPR30 is important for several metabolic functions in female mice, including estradiol-stimulated insulin release.
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| 2. |
- Li, Lizhen, 1977, et al.
(författare)
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Protective role of reactive astrocytes in brain ischemia.
- 2008
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Ingår i: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 28:3, s. 468-81
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Tidskriftsartikel (refereegranskat)abstract
- Reactive astrocytes are thought to protect the penumbra during brain ischemia, but direct evidence has been lacking due to the absence of suitable experimental models. Previously, we generated mice deficient in two intermediate filament (IF) proteins, glial fibrillary acidic protein (GFAP) and vimentin, whose upregulation is the hallmark of reactive astrocytes. GFAP(-/-)Vim(-/-) mice exhibit attenuated posttraumatic reactive gliosis, improved integration of neural grafts, and posttraumatic regeneration. Seven days after middle cerebral artery (MCA) transection, infarct volume was 210 to 350% higher in GFAP(-/-)Vim(-/-) than in wild-type (WT) mice; GFAP(-/-), Vim(-/-) and WT mice had the same infarct volume. Endothelin B receptor (ET(B)R) immunoreactivity was strong on cultured astrocytes and reactive astrocytes around infarct in WT mice but undetectable in GFAP(-/-)Vim(-/-) astrocytes. In WT astrocytes, ET(B)R colocalized extensively with bundles of IFs. GFAP(-/-)Vim(-/-) astrocytes showed attenuated endothelin-3-induced blockage of gap junctions. Total and glutamate transporter-1 (GLT-1)-mediated glutamate transport was lower in GFAP(-/-)Vim(-/-) than in WT mice. DNA array analysis and quantitative real-time PCR showed downregulation of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of tissue plasminogen activator. Thus, reactive astrocytes have a protective role in brain ischemia, and the absence of astrocyte IFs is linked to changes in glutamate transport, ET(B)R-mediated control of gap junctions, and PAI-1 expression.
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| 3. |
- Ning, Tong, 1975, et al.
(författare)
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Atmospheric Water Vapor Content Inferred From GPS Data and Compared to a Global NWP Model and a Regional Climate Model
- 2008
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Ingår i: 2008.10.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Radio based space geodetic methods are affected by the water vapor in the atmosphere.The velocity of the propagating signal is reduced, depending on the value of the refractiveindex. The atmospheric water vapor content, sometimes also called Integrated WaterVapor (IWV), can be inferred from the estimated propagation delay, or the excess propagationpath often expressed in units of length. The observations are relative measurementsof time, which makes the methods interesting from a calibration point of view - since timeis the physical parameter that we can measure with the highest accuracy.Since water vapor is difficult, and costly, to measure with a high temporal and spatialresolution, given its characteristics of variability, researchers in the atmospheric scienceshave shown interest in using data from already existing ground-based continuously operatingGPS receivers. Time series of the IWV from specific sites are now longer than tenyears. For example, 20 sites in the Swedish GPS network have produced continuous datasince 1993/1994. In addition to GPS also additional global navigational satellite systems(GNSS), such as the European Galileo and the finalization of the Russian GLONASS, willin the future significantly improve the spatial sampling of the atmosphere, and also reducethe relative influence of orbit errors for individual satellites.We have analyzed ground-based GPS data acquired in Europe and Africa over the period2001-2006. IWV results from the GPS data analysis are compared to the global NumericalWeather Prediction (NWP) models from the European Center for Medium RangeWeatherForecasting (ECMWF) as well as the regional climate model of the Rossby Center.The overall goal for the possible use of GNSS data in climate research is to determine towhich extent these independent data can be used to discriminate between different climatemodels - both in terms of absolute values as well as long term trends - thereby improvingthe quality of the models and increasing the probability to produce realistic scenarios ofthe future climate.
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