Sleep-disordered breathing with recurrent apnea produces chronic intermittent hypoxia (IH). We previously reported that IH leads to down-regulation of HIF-2α protein via a calpain-dependent signaling pathway resulting in oxidative stress. In the present study, we delineated the signaling pathways associated with calpain-dependent HIF-2α degradation in cell cultures and rats subjected to chronic...

Inflammation and ischemia--reperfusion tissue injury are important pathophysiologic processes with a wide spectrum of clinical presentations; the enzyme xanthine dehydrogenase/oxidase (XDH/XO) is thought to play a key role in ischemia--reperfusion injury. Recent studies have shown the transcriptional regulation of XDH/XO by cytokines (Dupont et al., 1992, J. Clin. Invest. 89, 197-202). In the p...

Xanthine oxidase (XO)-derived oxygen radicals are thought to play an important role in the intestinal injury resulting from ischemia and reperfusion. In vitro data shows enhanced XO activity in the presence of histamine. Histamine is known to be released during intestinal ischemia and reperfusion. The purpose of this study was to evaluate the relationship between histamine and XO in vivo in int...

of disease process & therapeutic targets Hyperuricemia, as defined by a serum urate ≥6.8 mg/dl, is necessary but not sufficient to produce the clinical manifestations of gouty arthritis (gout) [1]. Hyperuricemia develops whenever there is a relative imbalance of production and excretion of urate. There are several other risk factors associated with the development of gout, mostly related to the...

Oxidative stress may play a role in the pathogenesis of idiopathic pulmonary arterial hypertension (IPAH) [1–4]. A major contributor to oxidative stress is the endothelium-bound enzyme xanthine oxidase (XO), which is involved in the generation of superoxide anions and peroxynitrite [5]. These reactive oxygen species have been implicated in endothelial dysfunction and vascular damage [5]. In viv...

Consider the LTI system defined by the state space dual A = [ −p1 z − p2 0 −p2 ] , B = [ 1 1 ] where z = p1 and z = p2. (a) Is the system controllable? Explain your answer. Are there any pole-zero cancellations? (b) Assuming xo = 0, determine an expression for x(t) using modal analysis concepts. Determine a basis for the set of states that are reachable from xo = 0. (c) Does there exist a contr...

Der XO-Laptop ist mit einer Palette von Werkzeugen ausgestattet, die das Bearbeiten multimedialer Komponenten erlauben (Texte, Bilder, Videos), den Zugang zum Internet eröffnen und kollaboratives Arbeiten unterstützen. Ebenfalls enthalten sind mehrere Entwicklungsumgebungen zum Programmieren. Da die Adressaten primär Grundschüler sind, ist es nicht verwunderlich, dass dabei Anleihen bei der Pro...

In this study, a new method based on immobilized metal affinity chromatography (IMAC) combined with ultrafiltration-ultra performance liquid chromatography-mass spectrometry (UF-UPLC-MS) was developed for discovering ligands for xanthine oxidase (XO) in Gnaphalium hypoleucum DC., a folk medicine used in China for the treatment of gout. By IMAC, the high flavonoid content of G. hypoleucum could ...