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Necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is often regarded as one of the founders of modern pathology. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated digestion of cell components. In contrast, ''apoptosis'' is a naturally occurring programmed and targeted cause of cellular death. While apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal. Cellular death due to necrosis does not follow the apoptotic signal transduction pathway, but rather various receptors are activated and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates an inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coagulative Necrosis
Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction. In coagulative necrosis, the architectures of dead tissue are preserved for at least a couple of days. It is believed that the injury denatures structural proteins as well as lysosomal enzymes, thus blocking the proteolysis of the damaged cells. The lack of lysosomal enzymes allows it to maintain a "coagulated" morphology for some time. Like most types of necrosis, if enough viable cells are present around the affected area, Regeneration (biology), regeneration will usually occur. Coagulative necrosis occurs in most bodily organs, excluding the brain. Different diseases are associated with coagulative necrosis, including acute tubular necrosis and acute myocardial infarction. Coagulative necrosis can also be induced by high local temperature; it is a desired effect of treatments such as high intensity focused ultrasound applied to cancerous cells. Causes Coagulative necrosis is mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Injury
Cell damage (also known as cell injury) is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors. Cell damage can be reversible or irreversible. Depending on the extent of injury, the cellular response may be adaptive and where possible, homeostasis is restored. Cell death occurs when the severity of the injury exceeds the cell's ability to repair itself. Cell death is relative to both the length of exposure to a harmful stimulus and the severity of the damage caused. Cell death may occur by necrosis or apoptosis. Causes * Physical agents such as heat or radiation can damage a cell by literally cooking or coagulating their contents. * Impaired nutrient supply, such as lack of oxygen or glucose, or impaired production of adenosine triphosphate (ATP) may deprive the cell of essential materials needed to surv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biology), morphology) and death. These changes include Bleb (cell biology), blebbing, Plasmolysis, cell shrinkage, Karyorrhexis, nuclear fragmentation, Pyknosis, chromatin condensation, Apoptotic DNA fragmentation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 1,000,000,000, billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Death
Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as diseases, localized injury, or the death of the organism of which the cells are part. Apoptosis or Type I cell-death, and Autophagy (cellular), autophagy or Type II cell-death are both forms of programmed cell death, while necrosis is a non-physiological process that occurs as a result of infection or injury. The term "cell necrobiology" has been used to describe the life processes associated with morphological, biochemical, and molecular changes which predispose, precede, and accompany cell death, as well as the consequences and tissue response to cell death. The word is derived from the Greek language, Greek νεκρό meaning "death", βìο meaning "life", and logos, λόγος meaning "the study of". The term was initially coined to bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infarction
Infarction is tissue death (necrosis) due to Ischemia, inadequate blood supply to the affected area. It may be caused by Thrombosis, artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct (from the Latin ''infarctus'', "stuffed into"). Causes Infarction occurs as a result of prolonged ischemia, which is the insufficient supply of oxygen and nutrition to an area of tissue due to a disruption in blood supply. The blood vessel supplying the affected area of tissue may be blocked due to an obstruction in the vessel (e.g., an arterial embolus, thrombus, or atherosclerotic plaque), compressed by something outside of the vessel causing it to narrow (e.g., tumor, volvulus, or hernia), ruptured by trauma causing a loss of blood pressure downstream of the rupture, or vasoconstricted, which is the narrowing of the blood vessel by contraction of the muscle wall rather than an external force (e.g., cocaine vaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', ''dolor'', ''rubor'', ''tumor'', and ''functio laesa''). Inflammation is a generic response, and therefore is considered a mechanism of innate immunity, whereas adaptive immunity is specific to each pathogen. Inflammation is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and initiate tissue repair. Too little inflammation could lead to progressive tissue destruction by the harmful stimulus (e.g. bacteria) and compromise the survival of the organism. However inflammation can also have negative effects. Too much inflammation, in the form of chronic inflammation, is associated with variou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocyte
Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ''kutos,'' "hollow vessel". They are essential for fighting infections and for subsequent immunity. Phagocytes are important throughout the animal kingdom and are highly developed within vertebrates. One litre of human blood contains about six billion phagocytes. They were discovered in 1882 by Ilya Ilyich Mechnikov while he was studying starfish larvae.Ilya Mechnikov retrieved on November 28, 2008. Fro ''Physiology or Medicine 1901–192 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (medical)
Hypoxia is a condition in which the body or a region of the body is deprived of an adequate oxygen supply at the tissue (biology), tissue level. Hypoxia may be classified as either ''Generalized hypoxia, generalized'', affecting the whole body, or ''local'', affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise. Hypoxia differs from hypoxemia and anoxemia, in that hypoxia refers to a state in which oxygen present in a tissue or the whole body is insufficient, whereas hypoxemia and anoxemia refer specifically to states that have low or no Oxygen saturation (medicine), oxygen in the blood. Hypoxia in which there is complete absence of oxygen supply is referred to as anoxia. Hypoxia can be due to external causes, when the breathing gas is hypoxic, or internal causes, such as reduced effectiveness of gas transfer in the lung ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gangrene
Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the gangrene is caused by an infectious agent, it may present with a fever or sepsis. Risk factors include diabetes, peripheral arterial disease, smoking, major trauma, alcoholism, HIV/AIDS, frostbite, influenza, dengue fever, malaria, chickenpox, plague, hypernatremia, radiation injuries, meningococcal disease, Group B streptococcal infection and Raynaud's syndrome. It can be classified as dry gangrene, wet gangrene, gas gangrene, internal gangrene, and necrotizing fasciitis. The diagnosis of gangrene is based on symptoms and supported by tests such as medical imaging. Treatment may involve surgery to remove the dead tissue, antibiotics to treat any infection, and efforts to address the underlying cause. Surgical efforts may include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carina Kern
Carina Kern is a geneticist and biotechnology executive known for her work on the biology of aging, the molecular mechanisms of chronic disease and space biology. She is founder and CEO of LinkGevity Limited, a biotechnology company based at the Babraham Research Campus, affiliated with the University of Cambridge. Her work focuses on the development of therapeutics targeting degenerative processes, using artificial intelligence to guide drug discovery and molecular modeling. Kern was previously at the Department of Genetics, Evolution and Environment in the University College London. She has held academic and leadership roles in interdisciplinary networks, including serving as President of the London Evolutionary Research Network and Co-Chair of the CleanTech Business Challenge, an initiative co led by University College London and the London Business School. Early research Her early work on C. elegans has been regarded to challenge several decades of orthodoxy on the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischemia
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue, i.e., hypoxia and microvascular dysfunction. It also implies local hypoxia in a part of a body resulting from constriction (such as vasoconstriction, thrombosis, or embolism). Ischemia causes not only insufficiency of oxygen but also reduced availability of nutrients and inadequate removal of metabolic wastes. Ischemia can be partial (poor perfusion) or total blockage. The inadequate delivery of oxygenated blood to the organs must be resolved either by treating the cause of the inadequate delivery or reducing the oxygen demand of the system that needs it. For example, patients with myocardial ischemia have a decreased blood flow to the heart and are prescribe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
