Background: Pulmonary hypertension (PH) is characterized by profound vascular remodeling and alterations in Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Multiple transient receptor potential melastatin-related (TRPM) subtypes have been identified in vascular tissue. However, the changes in the expression and function of TRPM channels in pulmonary hypertension have not been characterized in detail. Methods: We examined the expression of TRPM channels and characterized the functions of the altered TRPM channels in two widely used rat models of chronic hypoxia (CH)- and monocrotaline (MCT)-induced PH. Results: CH-exposed and MCT-treated rats developed severe PH and right ventricular hypertrophy, with a significant decrease in TRPM8 mRNA and protein expression in pulmonary arteries (PAs). The downregulation of TRPM8 was associated with significant reduction in menthol-induced cation-influx. Time-profiles showed that TRPM8 down-regulation occurred prior to the increase of right ventricular systolic pressure (RVSP) and right ventricular mass index (RVMI) in CH-exposed rats, but these changes were delayed in MCT-treated rats. The TRPM8 agonist menthol induced vasorelaxation in phenylephrine-precontracted PAs, and the vasorelaxing effects were significantly attenuated in PAs of both PH rat models, consistent with decreased TRPM8 expression. Conclusion: Downregulation of TRPM8 may contribute to the enhanced vasoreactivity in PH.
Because of the rapid economy development and the enormous society evolution, large scale changes of land use and land cover had occurred in areas of Beijing and Hungary in the past two decades. This paper focused on monitoring on LUCC(land use and land cover change) in Changping,Beijing, China and Lake Velence watershed area in Szekesfehervar, Hungary based on Multi-Temporal, Multi-Spatial and multi-source remotely sensed images and Geographic Information System( GIS).
As a rapid developing area, Changping in Beijing, China, the change of land use and land cover(LUCC) had occurred at large scale in the recent 20 years. Remote sensing had provided the approach to monitoring LUCC and the environment response. The paper focus on monitoring LUCC and quantitative analysis of the thermal environment response. Based on the multi-temporal LandsatETM remote sensing images in 1999 and 2006, the earth surface brightness tempreture had been obtained by retrieving from LandsatTM6. The regional land use change and its spatio-temporal thermal environment evolution were analyzed with ENVI4.7 and Arc GIS 9.2. The research results showed that the land use changed evidently from 1999 to 2006. The regional urban expanding and the spatio-temporal thermal environment evolution was consistent from 1999 to 2006. By comparing the contrbution from the different land use types to the urban thermal environment effect, it was discovered that forest land was the largest contributor for the low area. The proportion of forest land decreased in the low temperature areas, and the proportion of urban land increased in high temperature area from 1999 to 2006. The urban heat island effect was obvious. The nakes arable land resulted the high temperature areas. The forest land and the agricultural land with the crop was helpful for the lower temperature areas.
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