Mitotic catastrophe

Mitotic catastrophe refers to a mechanism of delayed mitosis-linked cell death, a sequence of events resulting from premature or inappropriate entry of cells into mitosis that can be caused by chemical or physical stresses.[1] Mitotic catastrophe is unrelated to programmed cell death or apoptosis and is observed in cells lacking functional apoptotic pathways.[2] It has been observed following delayed DNA damage induced by ionizing radiation.[3] It can also be triggered by agents influencing the stability of microtubule spindles, various anticancer drugs and mitotic failure caused by defective cell cycle checkpoints.[4] Mitotic catastrophe is the primary mechanism underlying reproductive cell death in cancer cells treated with ionizing radiation.[2]

Not all cells die immediately following abnormal mitosis caused by mitotic catastrophe, but many do. Cells that do not immediately die are likely to create aneuploid cells following subsequent attempts at cell division posing a risk of oncogenesis (i.e. potentially leading to cancer). A very small fraction of these aneuploid cells produced by mitotic catastrophe might later reduce DNA ploidy by reductive division involving meiotic cell division pathways.[5][6][7]

External links

  1. ^ Ianzini F, Mackey MA (October 1997). "Spontaneous premature chromosome condensation and mitotic catastrophe following irradiation of HeLa S3 cells". International Journal of Radiation Biology. 72 (4): 409–21. doi:10.1080/095530097143185. PMID 9343106.
  2. ^ a b Ianzini F, Mackey MA (2007). "Mitotic Catastrophe". Apoptosis, Senescence, and Cancer. Humana Press. pp. 73–91. ISBN 978-1-58829-527-9.
  3. ^ Ianzini F, Mackey MA (July 1998). "Delayed DNA damage associated with mitotic catastrophe following X-irradiation of HeLa S3 cells". Mutagenesis. 13 (4): 337–44. doi:10.1093/mutage/13.4.337. PMID 9717169.
  4. ^ Castedo M, Perfettini JL, Roumier T, Andreau K, Medema R, Kroemer G (April 2004). "Cell death by mitotic catastrophe: a molecular definition". Oncogene. 23 (16): 2825–37. doi:10.1038/sj.onc.1207528. PMID 15077146.
  5. ^ Prieur-Carrillo G, Chu K, Lindqvist J, Dewey WC (June 2003). "Computerized video time-lapse (CVTL) analysis of the fate of giant cells produced by X-irradiating EJ30 human bladder carcinoma cells". Radiation Research. 159 (6): 705–12. doi:10.1667/rr3009. PMID 12751952.
  6. ^ Erenpreisa J, Kalejs M, Ianzini F, Kosmacek EA, Mackey MA, Emzinsh D, Cragg MS, Ivanov A, Illidge TM (December 2005). "Segregation of genomes in polyploid tumour cells following mitotic catastrophe". Cell Biology International. 29 (12): 1005–11. doi:10.1016/j.cellbi.2005.10.008. PMID 16314119.
  7. ^ Ianzini F, Kosmacek EA, Nelson ES, Napoli E, Erenpreisa J, Kalejs M, Mackey MA (March 2009). "Activation of meiosis-specific genes is associated with depolyploidization of human tumor cells following radiation-induced mitotic catastrophe". Cancer Research. 69 (6): 2296–304. doi:10.1158/0008-5472.can-08-3364. PMC 2657811. PMID 19258501.
Algor mortis

Algor mortis (Latin: algor—coldness; mortis—of death), the second stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body acclimates to the warmer environment. External factors can have a significant influence.

The term was first used by Dowler in 1849. The first published measurements of the intervals of temperature after death were done by Dr John Davey in 1839.

Anticancer gene

Anticancer genes are genes that, when ectopically overexpressed, specifically destroy tumour cells without harming normal cells. This cell destruction can be due to a variety of mechanisms, such as apoptosis, mitotic catastrophe followed by apoptosis or necrosis, and autophagy. Anticancer genes emerged from studies on cancer cells in the late 1990s.

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, or may result from such factors as disease, localized injury, or the death of the organism of which the cells are part. Apoptosis or Type I cell-death, and 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.

Chromosome

A chromosome is a deoxyribonucleic acid (DNA) molecule with part or all of the genetic material (genome) of an organism. Most eukaryotic chromosomes include packaging proteins which, aided by chaperone proteins, bind to and condense the DNA molecule to prevent it from becoming an unmanageable tangle.Chromosomes are normally visible under a light microscope only when the cell is undergoing the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, every chromosome is copied once (S phase), and the copy is joined to the original by a centromere, resulting either in an X-shaped structure (pictured to the right) if the centromere is located in the middle of the chromosome or a two-arm structure if the centromere is located near one of the ends. The original chromosome and the copy are now called sister chromatids. During metaphase the X-shape structure is called a metaphase chromosome. In this highly condensed form chromosomes are easiest to distinguish and study. In animal cells, chromosomes reach their highest compaction level in anaphase during chromosome segregation.Chromosomal recombination during meiosis and subsequent sexual reproduction play a significant role in genetic diversity. If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation, the cell may undergo mitotic catastrophe. Usually, this will make the cell initiate apoptosis leading to its own death, but sometimes mutations in the cell hamper this process and thus cause progression of cancer.

Some use the term chromosome in a wider sense, to refer to the individualized portions of chromatin in cells, either visible or not under light microscopy. Others use the concept in a narrower sense, to refer to the individualized portions of chromatin during cell division, visible under light microscopy due to high condensation.

Dead on arrival

Dead on arrival (DOA), also dead in the field and brought in dead (BID), indicates that a patient was found to be already clinically dead upon the arrival of professional medical assistance, often in the form of first responders such as emergency medical technicians, paramedics, or police.

In some jurisdictions, first responders must consult verbally with a physician before officially pronouncing a patient deceased, but once cardiopulmonary resuscitation is initiated, it must be continued until a physician can pronounce the patient dead.

Death hoax

A death hoax is a deliberate or confused report of someone's death that turns out to be incorrect and murder rumors. In some cases it might be because the person has intentionally faked death.

Death messenger

Death messengers, in former times, were those who were dispatched to spread the news that an inhabitant of their city or village had died. They were to wear unadorned black and go door to door with the message, "You are asked to attend the funeral of the departed __________ at (time, date, and place)." This was all they were allowed to say, and were to move on to the next house immediately after uttering the announcement. This tradition persisted in some areas to as late as the mid-19th century.

Death rattle

Terminal respiratory secretions (or simply terminal secretions), known colloquially as a death rattle, are sounds often produced by someone who is near death as a result of fluids such as saliva and bronchial secretions accumulating in the throat and upper chest. Those who are dying may lose their ability to swallow and may have increased production of bronchial secretions, resulting in such an accumulation. Usually, two or three days earlier, the symptoms of approaching death can be observed as saliva accumulates in the throat, making it very difficult to take even a spoonful of water. Related symptoms can include shortness of breath and rapid chest movement. While death rattle is a strong indication that someone is near death, it can also be produced by other problems that cause interference with the swallowing reflex, such as brain injuries.It is sometimes misinterpreted as the sound of the person choking to death, or alternatively, that they are gargling.

Dignified death

Dignified death is a somewhat elusive concept often related to suicide. One factor that has been cited as a core component of dignified death is maintaining a sense of control. Another view is that a truly dignified death is an extension of a dignified life. There is some concern that assisted suicide does not guarantee a dignified death, since some patients may experience complications such as nausea and vomiting. There is some concern that age discrimination denies the elderly a dignified death.

Dysthanasia

In medicine, dysthanasia means "bad death" and is considered a common fault of modern medicine.Dysthanasia occurs when a person who is dying has their biological life extended through technological means without regard to the person's quality of life. Technologies such as an implantable cardioverter defibrillator, artificial ventilation, ventricular assist devices, and extracorporeal membrane oxygenation can extend the dying process.

Dysthanasia is a term generally used when a person is seen to be kept alive artificially in a condition where, otherwise, they cannot survive; sometimes for some sort of ulterior motive. The term was used frequently in the investigation into the death of Formula One driver Ayrton Senna in 1994.

Lazarus sign

The Lazarus sign or Lazarus reflex is a reflex movement in brain-dead or brainstem failure patients, which causes them to briefly raise their arms and drop them crossed on their chests (in a position similar to some Egyptian mummies). The phenomenon is named after the Biblical figure Lazarus of Bethany, whom Jesus raised from the dead in the Gospel of John.

Maceration (bone)

Maceration is a bone preparation technique whereby a clean skeleton is obtained from a vertebrate carcass by leaving it to decompose inside a closed container at near-constant temperature. This may be done as part of a forensic investigation, as a recovered body is too badly decomposed for a meaningful autopsy, but with enough flesh or skin remaining as to obscure macroscopically visible evidence, such as cut-marks. In most cases, maceration is done on the carcass of an animal for educational purposes.

Megadeath

Megadeath (or megacorpse) is one million human deaths, usually caused by a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.

Necronym

A necronym (from the Greek words νεκρός, nekros, "dead" and ὄνομα ónoma, "name") is a reference to, or name of, a person who has died. Many cultures have taboos and traditions associated with referring to such a person. These vary from the extreme of never again speaking the person's real name, often using some circumlocution instead, to the opposite extreme of commemorating it incessantly by naming other things or people after the deceased.

For instance, in some cultures it is common for a newborn child to receive the name (a necronym) of a relative who has recently died, while in others to reuse such a name would be considered extremely inappropriate or even forbidden. While this varies from culture to culture, the use of necronyms is quite common.

Necrophobia

Necrophobia is a specific phobia which is the irrational fear of dead things (e.g., corpses) as well as things associated with death (e.g., coffins, tombstones, funerals, cemeteries). With all types of emotions, obsession with death becomes evident in both fascination and objectification. In a cultural sense, necrophobia may also be used to mean a fear of the dead by a cultural group, e.g., a belief that the spirits of the dead will return to haunt the living.Symptoms include: shortness of breath, rapid breathing, irregular heartbeat, sweating, dry mouth and shaking, feeling sick and uneasy, psychological instability, and an altogether feeling of dread and trepidation. The sufferer may feel this phobia all the time. The sufferer may also experience this sensation when something triggers the fear, like a close encounter with a dead animal or the funeral of a loved one or friend. The fear may have developed when a person witnessed a death, or was forced to attend a funeral as a child. Some people experience this after viewing frightening media.The fear can manifest itself as a serious condition. Treatment options include medication and therapy.The word necrophobia is derived from the Greek nekros (νεκρός) for "corpse" and the Greek phobos (φόβος) for "fear".

Pallor mortis

Pallor mortis (Latin: pallor "paleness", mortis "of death"), the first stage of death, is an after-death paleness that occurs in those with light/white skin.

Post-mortem interval

Post-mortem interval (PMI) is the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it. This also can refer to the stage of decomposition of the body.

Skeletonization

Skeletonization refers to the final stage of decomposition, during which the last vestiges of the soft tissues of a corpse or carcass have decayed or dried to the point that the skeleton is exposed. By the end of the skeletonization process, all soft tissue will have been eliminated, leaving only disarticulated bones. In a temperate climate, it usually requires three weeks to several years for a body to completely decompose into a skeleton, depending on factors such as temperature, humidity, presence of insects, and submergence in a substrate such as water. In tropical climates, skeletonization can occur in weeks, while in tundra areas, skeletonization may take years or may never occur, if subzero temperatures persist. Natural embalming processes in peat bogs or salt deserts can delay the process indefinitely, sometimes resulting in natural mummification.The rate of skeletonization and the present condition of a corpse or carcass can be used to determine the time of death.After skeletonization, if scavenging animals do not destroy or remove the bones, acids in many fertile soils take about 20 years to completely dissolve the skeleton of mid- to large-size mammals, such as humans, leaving no trace of the organism. In neutral-pH soil or sand, the skeleton can persist for hundreds of years before it finally disintegrates. Alternately, especially in very fine, dry, salty, anoxic, or mildly alkaline soils, bones may undergo fossilization, converting into minerals that may persist indefinitely.

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