Effecte of hyperoxia in bovine bronchail epithelial tissue Dissertation

Effecte of hyperoxia in bovine bronchail epithelial tissue - Dissertation Example Important Use of Hyperoxia in Intensive Care Unit Hyperoxic inspired gas is essential for patients with hypoxic respiratory failure which can be caused by oxygen deficient conditions like acute infection, neuromuscular impairment, etc. (Altemeler and Sinclair, 2007) In the context of critical care medicine, hyperoxia can be beneficial in implementing certain critical care strategies like early goal directed therapy (Calzia et al, 2010). Moreover, oxygen pressure field theory suggests that hyperoxia just before deep hypoxic circulatory arrest takes advantage of increased oxygen solubility and reduced oxygen consumption to load tissues with excess oxygen, which can effectively manage acid-base states during acute hypothermia entailed in circulatory arrest (Pearl et al, 2000) However, studies also testify that hyperoxia adversely affects cilial abundance and cause ciliary disorientation which can lead to dangerous conditions like ciliary dyskinesia (MacNaughton et al, 2007; Kay et al, 2 002; Rutman et al, 1993). Also, hyperoxia may impede the pathways of cell signalling (Lee and Choi, 2003) Side Effects of Reactive Oxygen Species (ROS) on Epithelial Tissue Reactive Oxygen Species (ROS) are oxygen containing molecules which are highly reactive. The unpaired valance shell electrons in ROS are responsible for their high reactivity. ROS are often regarded as a key factor behind cardiovascular diseases, ischemic injury, programmed cell death, etc. They can also cause damage to DNA, lipid peroxidation and critical oxidative stress. (Thannickal, 2003; Fuhrman et al 1997) ROS would cause oxidative stress on the epithelial tissue by increasing the levels of total glutathione. Since glutathione is an anti-oxidant, increased levels of ROS will increase its concentration as well. In the case of glutathione depletion, increase of ROS levels is unbridled which would lead to early activation of apoptic signalling. In vivo studies involving human B lymphoma cell line testify such possibilities (Armstrong et al, 2002). Moreover, it has also been testified that pulmonary macrophages stimulate cell proliferation of bovine bronchial epithelial cells in vitro. The process involves mediation in airway epithelial repair, which can probably be explained by a proactive role of glutathione against ROS (Takizawa et al, 1990). Another side effect of ROS is lipid peroxidation which has been studied in details through epithelial cell behaviour in vivo in rats with chronic parenchymal iron overload (Bacon et al, 1983). Hepatic and brain epithelial lipid peroxidation by ROS obtained from certain pesticides have been widely testified by both in vivo and in vitro studies in rats and humans (Bagchi et al, 1995). Besides, Fuhrman and his associates conducted in vitro and ex vivo studies in humans to testify the high extent of low-density-lipoprotein oxidation by ROS through measurement of thiobarbituric acid reactive substances (TBARS) and lipid peroxides in epithelial cells (F uhrman et al, 1997). Proteins modification is another major side effect of excess ROS generation that has been studied in vivo. The in vivo study conducted in this context further testified that oxidative protein damage could affect the activities of the DNA repair enzymes in the epithelial cells as well (Wiseman and Halliwell, 1996). Further, in vitro studies have established that generation of ROS target the function of redox-sensitive proteins that act as part of a large sub-membranous

International Theory Essay Example | Topics and Well Written Essays - 1000 words

International Theory - Essay Example s came about, and two of these theories emerged to what we presently know as the English School and the Classical Liberalism theories in international relations. These theories shall be discussed and differentiated in this paper. Classical liberalism believes that if people are given as much freedom as possible, the principles of authoritarianism shall eventually fade away, democracy shall have a chance to emerge, and wars will eventually cease to exist. Classical liberalism in international relations has four main beliefs. First and foremost, classical liberalists believe that peace can best be achieved through the more widespread application of democratic principles. Classical liberalism prescribes to the notion of institutional liberalism, in the sense that it desires for more nations to be more democratic in their political approach. They believe that democracy epitomizes the perfect breeding ground for peace within and among nations. Secondly, they believe that naturally harmonious interests will help ensure that citizens and states â€Å"make rational calculations which make national interest and international interest one and the same† (O’Connor, 2008). They advocate the belief that the state preferences, not the state capabilities determine the behaviour of the state. It therefore has a high degree of tolerance for various preferences. Thirdly, disputes should be settled by the set judicial procedures under the rule of law. Classical liberalism stresses that the rule of law is applicable to states, not just to people. It advocates that it is possible to identify aggressors and belligerents; therefore, it is also possible to come up with an effective coalition of states opposing such violators. Finally, collective security would replace notions of self-help. They agree that different states may have different preferences, and that governments actually make the decisions to go to war, not people. And they ultimately prefer adherence to the