Why are oxides harmful

Indeed, prosthetic biomaterials used in medical devices were modified through covalent or noncovalent binding of two NO donors diazeniumdiolates and S-nitrosothiols. Several clinical trials have shown their usefulness in the context of preventing thrombus formation [ 87 ].

NO-donating nanoparticle systems represent a new promising tumoricidal agents, thanks to their unique properties: i strengthening NO-donor stability, ii loading a large amount of NO, and iii possibility to trigger NO releasing [ 88 ].

The modulation of NOS activity is another interesting strategy. However, since l -arginine is the common point between all NOS isoforms, these analogs represent nonselective drugs. Moreover, such therapy did not reach clinical studies on human stage despite its effects on canine vascular tone [ 89 ]. Thus, investigation on a more selective inhibition of iNOS, crucial for inflammation, was conducted through transgenic animals. Unfortunately, iNOS knockout mice exhibit an increase in mortality following polymicrobial sepsis [ 90 ].

More recently, researcher focused on increasing NO delivery within cancers. Thus, thanks to technical progress and scientific knowledge updating, iNOS-based suicide gene therapy was investigated through viral vector use. This treatment exhibits promising tumoricidal effects and appears interesting for its specific and localized iNOS expression on animal models [ 91 ].

The third strategy is the direct gaseous delivery of NO in the treatment of various infection diseases related to antibiotic resistant bacteria. Ghaffari et al.

First, they developed an ingenious delivery system usefulness for the monitoring of gNO effects on microorganisms bacteria and fungi and eukaryotic cells [ 92 ]. Then, they reported an effective concentration of gNO up to ppm in continuous 4 h delivery exhibiting bacteriostatic effects on a representative group of microorganisms Staphylococcus aureus , Pseudomonas aeruginosa , E.

Moreover, no toxic effects were observed on representative mammalian cell lines dermal fibroblasts of wound-healing pathology such as leg ulcer or burn injuries [ 93 ]. Thus, these promising results placed gNO as a potential topical antibiotic agent [ 94 ].

Later, they also investigated the potential use of inhaled gNO in the treatment of pathogenic infection in the case of cystic fibrosis. Indeed, this pathology is a threatening pulmonary disease where microbial infection could be lethal. However, a continuous exposure of gNO at such concentration can lead to severe impact on the human health, particularly through methemoglobinemia.

This phenomenon occurs when hemoglobin losses its vital function of oxygen carrier following the saturation of its iron heme with NO. An adapted lung mammalian model was also used macrophages and monocytes and pulmonary epithelial cells to appreciate the potential effects of this cure on human health [ 95 ].

This study reached phase I clinical studies using a promising NO treatment at ppm for 30 min three times daily for two periods of 5 days [ 96 ]. However, as reviewed by Petit et al. They also reported that the higher NO doses are used, the faster is the formation rate of NO 2.

In contrast, a direct gaseous NO 2 exposure could also be benefit in the struggle against undesirable microorganism because it seems to impact their metabolism, social behavior, and growth [ 84 ]. Moreover, a continuous high-dose NO 2 exposure seems to lead in membrane alteration through an increased permeability [ 98 ].

In summary, this review of the literature shows that NOx is ubiquitous and essential in our lives. We are exposed to these compounds through environmental contaminations, but they also result from physiological processes, infections, diseases, or even drugs. NO and derivatives are implicated in a large diversity of vital functions including brain functions; motricity; cardiac, vascular, and pulmonary functions; and immunity.

For these reasons, NOx is key molecules of major biochemical interest. As all active substances, NOx can exert both beneficial and adverse effects with regard to the exposition dose. The physiological adaptation to NOx results from a fine-tuned equilibrium where detoxification plays crucial roles. Myriad of finely regulated processes has emerged in response to nitrosative stress. Our knowledge still remains incomplete, and future studies are necessary to finely precise the synergy of each NOx implemented in nitrosative stress, especially when they are presented in gaseous phase that remains less explored.

However, in spite of all previously described mechanisms to counteract the nitrosative stress, abnormal NOx thresholds could trigger a wide range of pathologies and even death. These antagonists, positive and negative effects, of NOx are actually intriguing.

So, many researches are now focusing on NOx producing pathways to find the most effective treatments and drugs. More investigations are still needed to better understand the real potential of NOx as antitumor, antibacterial agents, and their safe clinical use.

We thank Dr. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Sonia Soloneski. By Shoil M. Greenberg, John J. Adamczyk and John S. We are IntechOpen, the world's leading publisher of Open Access books.

Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Abstract Nitrogen oxide NOx species represent ones of the most threatening air pollutants due to their prevalence and harmful impact on the environment and human health.

Keywords NOx pollutants signalization physiopathology treatment. Exogenous NOx: a hostile intruder inside the eukaryotic cells Much work was already performed on NOx targets at the cell scale.

Endogenous NO: an essential mediator of cellular signalization Interestingly, NO can also be produced by several living organisms: plants, animals, and bacteria, thanks to a specific enzyme called nitric oxide synthase NOS [ 27 , 28 ]. The endothelial eNOS and vasodilatation Endothelial nitric oxide synthase eNOS can be activated through calcium-dependent and independent pathways. There are all sorts of things that we can do at home, school, and in our local community to help minimise the harmful effects of pollution on our environment.

Why not investigate ways in which you can take action every day to reduce the problems that polluting substances can cause people, animals and the environment? More about reducing pollution. For more information about oxides of nitrogen see Australia's oxides of nitrogen emission report on the main NPI web site. You will also find detailed information about the remaining 92 substances that the NPI tracks across Australia in the fact sheets on the main NPI web site.

Skip to main content. Download Oxides of nitrogen PDF - What does the National Pollutant Inventory do? Spike at the power station Where do oxides of nitrogen come from? What about industry?

What about the natural environment? What about transport? Nitrogen Dioxide NO2 Pollution. Contact Us. Basic Information about NO2. NO 2 and other NO x interact with water, oxygen and other chemicals in the atmosphere to form acid rain.

Acid rain harms sensitive ecosystems such as lakes and forests. The nitrate particles that result from NO x make the air hazy and difficult to see though. Nitrogen dioxide can fade and discolour furnishings and fabrics, reduce visibility, and react with surfaces.

Typical outdoor nitrogen dioxide levels are well below the 1-hour standard and exposure at these levels does not generally increase respiratory symptoms. This particular reaction is the oxidation of nitric oxide NO to nitrogen dioxide NO 2 by ozone O 3 as shown below:. A photomultiplier tube measures the intensity of the emitted light. Since 1 NO molecule is required to form 1 NO 2 molecule, the intensity of the chemiluminescent reaction is directly proportional to the NO concentration in the sample.

The analyser measures the amount of light emitted and converts this to a concentration. A vacuum pump draws both the air supply for the ozone generator and the ambient air samples into the analyser. The green dot shows the ambient air sample path.