Hypertension is a significant risk factor for diverse cerebrovascular diseases ranging from stroke to arteriovenous malformations and saccular aneurysms. Our increasing understanding of vascular mechanobiology reveals that changes in mechanical stimuli, such as increased blood pressure, alter basic cellular functions including the production and degradation of extracellular matrix as well as proliferation, migration, and apoptosis. Understanding changes in the biomechanical properties of the vascular wall is fundamental to correlating mechanobiological responses with the altered loads. In this paper, we present the first biomechanical data on a large cerebral artery in terms of the time of development of hypertension in maturity. Specifically, we report rapid changes in both the structural and the material stiffness of the passive basilar artery in a novel aortic-coarctation model of hypertension in the mini-pig. Histological measurements reveal associated increases in fibrillar collagens in the media and adventitia as well as increased smooth muscle in the media. That such dramatic changes occur within 2 weeks of the initiation of hypertension in maturity necessitates a detailed study of the early changes as well as the potential to reverse these changes at later times.
Multiphoton laser-scanning microscopy (MPLSM) imaging in combination with advanced image analysis techniques provides unique opportunities to visualize the arrangement of cholesterol in the plasma membrane (PM) of living cells. MPLSM makes possible the use of a naturally occurring sterol, dehydroergosterol (DHE), for observing sterol-enriched areas of the PM. Pure DHE has properties similar to cholesterol as observed in model and cellular membranes but with a conjugated double-bond system that fluoresces at ultraviolet wavelengths. MPLSM enables the excitation of DHE at infrared wavelengths that many laser-scanning microscopy systems are able to transmit effectively and that are less harmful to the cell. Thus, with the incorporation of DHE into living cells and the advent of MPLSM, real-time images of the cellular distribution of DHE can be obtained. In juxtaposition, notably the application of newly advanced techniques in image analysis, aids not only the identification and segmentation of sterol-rich regions of the PM of cells, but also the elucidation of the statistical nature of the observed patterns. In studies involving murine L-cell (Larpt-+K-) fibroblasts, DHE is shown to exhibit strong cluster patterns within the PM.
Atmospheric trace phthalic esters (PAEs) carried by total suspended particulates were systematically investigated. A total of 450 air samples were collected at six typical locations and three specific micro-environmental sites (a stadium with a new plastic track, new cars, and a farming greenhouse with plastic film) in Nanjing metropolitan area of China from April 2009 to January 2010. The samples were analyzed by high-performance liquid chromatography and ultraviolet detection. The results are summarized as follows: (1) The dominant PAEs are dimethyl phthalate (DMP), dibutyl phthalate (DBP), and diethylhexyl phthalate (DEHP), which were found in the atmosphere of Nanjing. The average concentrations of DMP, DBP, and DEHP were 10.5 ± 1.2, 62.3 ± 4.5, and 33.3 ± 2.5 ng m(-3), respectively, constituting 9.9%, 58.7%, and 31.4% of total PAEs (106 ± 8.2 ng m(-3)). (2) The dynamic variations of atmospheric PAEs in the three specific micro-environmental sites showed that the PAE concentrations in the stadium with a new plastic track reduced to normal after 1 month remediation, while new cars need 6 months to remove their effect. The levels of PAEs in a farming greenhouse with plastic film were relatively high, but little PAEs accumulated in vegetables. (3) The vertical profiles from 1.5 to 40 m above ground display some fluctuations in PAE concentration, but no significant height dependence. This information will make a valuable contribution to the examination of the influence of atmospheric PAEs on the environment and human health.
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