**6.2 Free radical cause nitric oxide**

The rate of whole body NO synthesis was increased in the end stage renal disease (ESRD) patients [108]. In several animal models of renal disease, the increase in NO synthesis is associated with reduced degree of glomerulosclerosis, infiltration of the kidney by invading macrophages [109]. The relations between endothelial and inducible nitric oxide synthases are perturbed in renal ischemia primarily as a result of endothelial dysfunction [110]. The nitric oxide is highly reactive and exerts its chronic effects only at high concentrations which are responsible for the complications of dialysis of patients with chronic kidney disease [111]. Patients with chronic kidney disease (CKD) have been found the decreased levels in all stages of CKD [112]. Intracellular nitric oxide (iNO) substantially increased the risk of renal

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*Diseases Related to Types of Free Radicals DOI: http://dx.doi.org/10.5772/intechopen.82879*

the incidence of acute kidney injury [115].

**7. Some other type of free radicals**

5-(hydroxymethyl) uracil [118].

cell membranes. [120].

creates other free radicals.

**7.4 Singlet oxygen**

Singlet oxygen (1

**7.2 Free radical cause lipid peroxidation**

**7.3 Superoxide oxygen (O2∙—one electron)**

**7.1 Hydroxyl radicals**

dysfunction in patients with acute respiratory distress syndrome (ARDS) [113]. The process of oxidative stress affects kidney function by elevated the damage in renal vessels, glomeruli, and tubules [114]. In patients with multiple valve replacement and prolonged cardiopulmonary bypass, administration of nitric oxide decreased

It is the most reactive of the free radical molecules. It damages cell membranes

and lipoproteins by lipid peroxidation. Damage to lipoproteins in low density lipoprotein plays an important role in atherosclerosis. ∙OH is formed by radiolysis of water and by reaction of H2O2 with ferrous (Fe2+) ions; the latter process is termed as Fenton reaction [116, 117]. The reactive oxygen species, hydroxyl (∙OH) radical is one of the potential inducers of DNA damage. A variety of adducts are formed on reaction of ∙OH radical with DNA. The ∙OH radical can attack purine and pyrimidine bases to form ∙OH radical adducts, which are both oxidizing and reducing in nature which in turn can induce base modifications and sometimes release of bases. Some of the important base modifications include 8-hydroxydeoxyguanosine (8-OHdG), 8 (or 4-,5-)-hydroxyadenine, thymine peroxide, thymine glycols, and

Lipids that contain phosphate groups (i.e., phospholipids) are essential components of the membranes that surround the cells and cell structures. Free radicals in the presence of oxygen may cause degradation (peroxidation) of lipids within plasma and organellar membranes. Oxidative damage is initiated when the double bonds in unsaturated fatty acids of membrane lipids are attacked by oxygen derived free radicals particularly by OH. The lipid free radical interactions yield peroxides, which are themselves unstable and reactive, and an autocatalytic chain reaction called propagation ensues which can result in extensive membrane, organellar, and cellular damage [116, 119]. Oxidative destruction of polyunsaturated fatty acids by lipid peroxidation is damaging because it may alter the integrity of

It is generated by direct auto-oxidation of O2 during mitochondrial electron transport reaction. Alternatively, O2∙ is produced enzymatically by xanthine oxidase and cytochrome P450 in the mitochondria or cytosol [121]. O2∙ so formed is catabolized to produce H2O2 by superoxide dismutase (SOD), a metalloprotein. It is considered to be the least reactive type of ROS and the most commonly produced free radical in humans. Once it is produced, it triggers a rapid cascade of events that

known to be formed when photosensitizers such as chlorophyll or the aromatic dye rose Bengal absorb light energy and transfer some of that energy to molecular oxygen

O2) is an electronically excited form of oxygen which is well

dysfunction in patients with acute respiratory distress syndrome (ARDS) [113]. The process of oxidative stress affects kidney function by elevated the damage in renal vessels, glomeruli, and tubules [114]. In patients with multiple valve replacement and prolonged cardiopulmonary bypass, administration of nitric oxide decreased the incidence of acute kidney injury [115].
