Cell Damage May Be Caused by Exogenous Sources Such as

Some of these sources may be so common that most humans are exposed to small amounts and it is difficult to apportion the exogenous and endogenous contributions Zhao et al. ROS are produced as.

Types Of Free Radicals Oxidants And Their Endogenous And Exogenous Download Scientific Diagram

In principle cell injury can occur due to the following factors.

. The causes of cell injury are classified as exogenous or endogenous. The damage to cells caused by free radicals especially the damage to DNA may play a role in the development of cancer and other health conditions 1 2. ROS can damage lipids DNA RNA and proteins which in theory contributes to the physiology of aging.

ROS have long been implicated in oxidative damage and. At high levels ROS can lead to impaired physiological function through cellular damage of DNA proteins lipids and other macromolecules which can lead to certain human pathologies including cancers neurodegenerative disorders and cardiovascular disease as. 101016jbbcan201711002 Abstract The DNA of all living cells undergoes continuous structural and chemical alteration which may be derived from exogenous sources or endogenous metabolic pathways such as cellular respiration replication and DNA demethylation.

Damage caused by different exogenous agents result in different damages. Action of toxins and other adverse influences that could inhibit the vital cell functions eg oxidative phosphorylation or protein synthesis. The latter may be formed endogenously from cellular precursors but they may also originate from exogenous sources such as diet tobacco smoke or environmental pollution.

Reactive oxygen species ROS with the potential to cause cellular damage are produced along with the release of energy. UV-B light causes crosslinking between adjacent cytosine and thymine bases creating pyrimidine dimers. With phototoxicity light may originate directly from exogenous sources such as the sun artificial lighting or photodynamic topical chemicals or it may emanate from endogenous sources such as photodynamic drugs or chemicals following activation or excitation by percutaneous irradiation.

Damage to these cells may be caused by clinically administered drugs such as aminoglycoside antibiotics and some chemotherapeutics eg cisplatin exposure to high levels of sound aging infections some occupational hazards. Most cases of hearing impairment are due to degeneration of sensory hair cells HCs the mechano-receptors in the inner ear. All eukaryotic cells have evolved a multifaceted response to counteract the potentially.

Oxidative damage to DNA bases occurs when an oxygen atom binds to a carbon atom in the DNA base. Cancer may be a pathway to cell survival under. DNA damage is caused by a variety of sources.

Free radical formation occurs continuously in the cells as a consequence of both enzymatic and nonenzymatic reactions. DNA damage arises from both endogenous sources such as water and oxygen and exogenous sources such as sunlight and tobacco smoke. Endogenous ROS are produced as a byproduct in subcellular organelles such as mitochondria peroxisomes and cytochrome P-450.

In human cells both normal metabolic activities and environmental factors such as radiation can cause DNA damage resulting in tens of thousands of individual molecular lesions per cell per day. For example hydroxyl radical and peroxynitrite in excess can damage cell membranes and lipoproteins by a process called lipid peroxidation. Abnormally high concentrations of free radicals in the body can be caused by exposure to ionizing.

Electron leakage that occurs from. 1 endogenous damage caused by reactive oxygen species ROS that are derived from metabolic byproducts and 2 exogenous damage caused by radiation UV X-ray gamma hydrolysis plant toxins and viruses. High-energy radiation like X-rays and gamma radiation causes exogenous oxidative DNA base damage by interacting with water molecules to create highly reactive oxygen species which then attack DNA bases at susceptible carbon atoms.

Cell injury may occur by a variety of mechanisms and sources - endogenous ischemiainflammation or exogenous drugstoxins Cell injury can be reversible or irreversible. Endogenous sources and characteristics of oxygen radicals Other than the exogenous sources such as exposure to radiation enzymatically or non-enzymatically mediated e lct ron a sf ih u d produced in the cells. The genetic information contained within the DNA molecule is highly susceptible to chemical and physical insult caused by both endogenous and exogenous sources that can generate in the order of thousands of lesions a day in each of our cells Lindahl Nature 362 6422709-715 1993.

DNA damage can be subdivided into two types. Cells are exposed to both endogenous and exogenous sources of reactive oxygen species ROS. Reversible cell injury can result in changes which may recover when the cause is removed or which may persist.

ROS and reactive nitrogen species are generated from either endogenous such as immune cell activation inflammation mental stress excessive exercise ischemia infection cancer aging or exogenous sources such as air pollution water pollution cigarette smoke alcohol heavy metals transition metals pharmaceutical substancespharmacological agents and radiation78. DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. Free radicals and other ROS are derived either from normal essential metabolic processes in the human body or from external sources such as exposure to X-rays ozone cigarette smoking air pollutants and industrial chemicals.

Excessive or overly prolonged normal stimuli. ROS could be produced endogenously by normal cellular metabolism and inflammatory process or due to exogenous exposure or ingestion of environmental toxicants. Cell damage may be caused by exogenous sources such as.

In human cells base alterations are generally removed by excision repair pathways that counteract the. This inflammatory microenvironment can cause DNA damage in hematopoietic cells. Many of these lesions cause structural damage to.

The cellular response to damage may involve activation of a cell cycle checkpoint commencement of transcriptional programs execution of DNA repair or when the damage is severe initiation of apoptosis. Oxidative stress can arise when cells cannot adequately destroy the excess of free radicals formed. ROS are produced inside the cells both by endogenous and exogenous sources.

In other words oxidative stress results from an imbalance between formation and neutralization of ROSRNS. And accumulation of such damage may con-tribute to ageing and age related diseases. Cell damage may be caused by exogenous sources such.

Endogenous And Exogenous Agents Causing Dna Damage Oxidative Stress Download Scientific Diagram

Dna Damage Response R D Systems

Reactive Oxygen Species Ros Can Be Produced By 1 Exogenous Sources Download Scientific Diagram