Olalekan Bukunmi Ogunro

By Olalekan Bukunmi Ogunro, Aderonke Elizabeth Fakayode and Gaber El-Saber Batiha

Oxidative stress occurs when the body’s enzymatic or non-enzymatic antioxidants are outweighed by endogenous or exogenous free radicals. Oxidative radicals, reactive oxygen species, and other biomolecule-damaging free radicals can be generated during normal cellular metabolism and react with proteins, lipids, and DNA. In the domains of biology and medicine, free radicals have become increasingly important. They can accumulate in a variety of ways, both endogenously and exogenously. Mitochondria are the primary source of cell-level endogenous reactive oxygen species. In several chronic and degenerative disorders, this results in tissue destruction. In addition to being produced endogenously, antioxidants can also be delivered exogenously to the biological system, most frequently through nutrition. Antioxidants are generally used to counteract the effects of free radicals produced by metabolic processes. In this chapter, the crucial function of reactive oxygen species in human health, as well as exploring the functioning of antioxidative defense systems in reducing toxicity caused by excess reactive oxygen species were discussed.

Part of the book: Importance of Oxidative Stress and Antioxidant System in Health and Disease

By Olalekan Bukunmi Ogunro and Oladimeji Taiwo Babatunde

Epigenetic alterations are one of the distinctive characteristics of aging. Epigenetics changes throughout the reproductive life of humans. The major epigenetic parameters viz. DNA methylation, histone modification, and chromatin modeling are altered in the oocyte and sperm due to aging. Also, aging is accompanied by oxidative stress resulting in oocyte and sperm DNA damage. Oxidative stress occurs when the body’s antioxidant defense mechanism is overwhelmed by free radicals or pro-oxidant molecules such as nitrogen and reactive oxygen species, which are generated during normal cellular metabolism. This phenomenon is accompanied by a decline in the cell repair machinery, resulting in a wide range of DNA damage and distortion in cellular epigenetics. Still more, free radicals can directly or indirectly interfere with some epigenetic processes of the cell. For example, free radicals can impart the genome methylation profile by forming oxidized DNA lesions. Given the deleterious impact of oxidative stress on aging and cellular epigenetic profile, the ingestion of external antioxidants is encouraged to circumvent its side effects. This chapter provides insight into the interconnection between epigenetic alterations (histone modification, chromatin remodeling, DNA methylation and miRNA), reproductive aging, and oxidative stress.

Part of the book: Epigenetics

By Olalekan Bukunmi Ogunro and Oluwaseun Ruth Olasehinde

Respiratory failure, characterized as the unsuccessful maintenance of adequate gas exchange, is associated with abnormalities of arterial blood gas tensions. The coronavirus disease-2019 (COVID-19) is majorly a respiratory disease capable of causing infection caused by the newly discovered coronavirus (SARS-CoV-2) with a consequential effect on respiratory failure. Simply put, respiratory failure is the major clinical demonstration of COVID-19 and the frontline cause of the associated mortality. Respiratory failure instigated by COVID-19 has some clinical features in affected patients. Disorders of the respiratory neuromuscular, airway, pulmonary vesicles, and lung parenchyma all manifest in COVID-19. These features are heterogeneous and categorized into progressive respiratory distress and unique “silent hypoxemia” as two phenotypes. Knowing the exact phenotype in patients with COVID-19 has been of important clinical significance in seeking the right treatment strategies for treating respiratory failure. The chapter will, therefore, provide more insights into the pathophysiology, clinical attributes, pathogenesis, and treatment approach of respiratory failure in COVID-19 conditions, as well as evaluate any similarities and differences that may exist.

Part of the book: Respiratory Insufficiency