From the analysis of the 13-color photometry and spectroscopy of
HD 184279 (V 1294 Aql), we have found that for the last 10 years, this atar presents a pseudo period of 5.0 years both in light and radial velocity. There is a phase difference of 0.148 P (8.9 months) between the maximum of light and the minimum of radial velocity. The magnitude of the star changes by 0.4 mag. and the radial velocity shows a range ef 185 km/sec. A comparison with theoretical models give ua an Teff.<=28, 700 K with log.g<=4.0 in agreement with spectroscopic determinations.
The atar is reaching the maximum of light and some of their shell features are decreasing, a probable indication that the atar may return to a quiesent stage on its evolution, or it will continue the cyclic behaviour that has characterize it for the last 10 years. Its observation in UV and IR wavelenghts should be very important to measure the wind that may be present in the well developed shell surrounding the atar.
Our own study as well as others have previously reported that hypoxia activates 15-lipoxygenase (15-LO) in the brain, causing a series of chain reactions, which exacerbates ischemic stroke. 15-hydroxyeicosatetraenoic acid (15-HETE) and 15-oxoeicosatetraenoic acid (15-oxo-ETE/15-KETE) are 15-LO-specific metabolites of arachidonic acid (AA). 15-HETE was found to be rapidly converted into 15-oxo-ETE by 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in some circumstances. We have demonstrated that 15-HETE promotes cerebral vasoconstriction during hypoxia. However, the effect of 15-oxo-ETE upon the contraction of cerebral vasculature remains unclear. To investigate this effect and to clarify the underlying mechanism, we performed immunohistochemistry and Western blot to test the expression of 15-PGDH in rat cerebral tissue, examined internal carotid artery (ICA) tension in isolated rat ICA rings. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of voltage-gated potassium (Kv) channels (Kv2.1, Kv1.5, and Kv1.1) in cultured cerebral arterial smooth muscle cells (CASMCs). The results showed that the levels of 15-PGDH expression were drastically elevated in the cerebral of rats with hypoxia, and 15-oxo-ETE enhanced ICA contraction in a dose-dependent manner. This effect was more significant in the hypoxic rats than in the normoxic rats. We also found that 15-oxo-ETE significantly attenuated the expression of Kv2.1 and Kv1.5, but not Kv1.1. In conclusion, these results suggest that 15-oxo-ETE leads to the contraction of the ICA, especially under hypoxic conditions and that specific Kv channels may play an important role in 15-oxo- ETE-induced ICA constriction., Di Wang, Yu Liu, Ping Lu, Daling Zhu, Yulan Zhu., and Obsahuje bibliografii