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Drug Overdose

Drug overdose

A drug overdose occurs when a chemical substance (i.e. drug) is ingested in quantities and/or concentrations large enough to overwhelm the homeostasis of a living organism, causing severe illness or death. Essentially it is a type of poisoning.

Types

The word "overdose" implies that there is a safe dosage and therefore the term overdose is commonly only applied to drugs, not poisons. Drug overdoses are often used to commit suicide, but many drug overdoses are unintentional and are usually the result of either irresponsible behavior (such as overindulging at a college keg party), or the misreading of product labels (such as taking 4 pills every 1 hour instead of 1 pill every 4 hours). Other causes of overdose (esp. heroin) include poly drug use with contra-indications (cocaine/amphetamines/alcohol) and use after a period of abstinence. A common unintentional overdose in young children involves multi-vitamins containing iron. Iron is component of the hemoglobin molecule in blood, used to transport oxygen to living cells. When taken in small amounts, iron allows the body to replenish hemoglobin, but in large amounts it causes severe pH imbalances in the body. If this overdose is not treated with chelation therapy, it can lead to death.

Symptoms

Symptoms of overdose occur in various forms:
- Exaggerated form of normal action (sleepiness on antiepileptics, hypoglycemia on insulin)
- Other effects due to chemical properties of the medication (metabolic acidosis in aspirin, liver failure due to paracetamol)
- Non-specific symptoms due to central nervous system irritation (confusion, vertigo, nausea, vomiting)

Diagnosis and management

Diagnosis and management are generally straightforward if the drug is known. The diagnosis can be very difficult if the patient cannot (or refuses to) state which medication has been overdosed. At times, certain symptoms and signs exhibited by the patient, or blood tests, can reveal the drug in question. Even without knowing the drug, most patients can be treated with general supportive measures. In some instances, empirical antidotes may be administered if there is sufficient indication that the patient has overdosed on a particular type of medication: naloxone in opioids and flumazenil in benzodiazepines. Rapid reversal of symptoms may serve as proof in these cases.

Common causes

Common types of drugs that are overdosed on:
- Barbiturates
- Seconal
- Nembutal
- Narcotics
- Heroin
- Stimulants
- Cocaine
- Ethyl Alcohol
- Alcoholic beverages

Chemical

A chemical substance is any material substance used in or obtained by a process in chemistry:
- A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions.
- A chemical element is a substance that cannot be divided or changed into different substances by ordinary chemical methods. The smallest particle of such an element is an atom, which consists of electrons centered on a nucleus of protons and neutrons.
- A molecule is the smallest particle of an element or compound that retains the characteristics of the element or compound.
- An ion is an atom or group of atoms with a net electric charge, having lost (cation) or gained (anion) an electron.
- A chemical reaction is a process involving one, two or more substances (called reactants), characterized by a chemical change and yielding one or more product(s) which are different from the reactants. Category:Chemistry ja:薬品 th:สารเคมี

Concentration

:For the psychological concept, see attention. For the game, see Concentration (game), for the game show, see Concentration (game show). In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance. This can apply to any sort of chemical mixture, but most frequently is used in relation to solutions, where it refers to the amount of solute dissolved in a solvent. To concentrate a solution, one must add more solute, or reduce the amount of solvent (for instance, by selective evaporation). By contrast, to dilute a solution, one must add more solvent, or reduce the amount of solute. There exists a concentration at which no further solute will dissolve in a solution. At this point, the solution is said to be saturated. If additional solute is added to a saturated solution, it will not dissolve. Instead, phase separation will occur, leading to either coexisting phases or a suspension. The point of saturation depends on many variables such as ambient temperature and the precise chemical nature of the solvent and solute. Concentration may be expressed both qualitatively ('informally') or quantitatively ('numerically').

Qualitative notation

Qualitatively, solutions of relatively low concentration are described using adjectives such as "dilute," or "weak," while solutions of relatively high concentration are described as "concentrated," or "strong." As a rule, the more concentrated a chromatic solution is, the more intensely coloured it is. chromatic

Quantitative notation

Quantitative notation of concentration is far more informative and useful from a scientific point of view. There are a number of different ways to quantitatively express concentration; the most common are listed below. Note: Many units of concentration require measurement of a substance's volume, which is variable depending on ambient temperature and pressure. Unless otherwise stated, all the following measurements are assumed to be at standard state temperature and pressure (that is, 25 degrees Celsius at 1 atmosphere or 101.325 kPa).

Mass percentage

Mass percentage denotes the mass of a substance in a mixture as a percentage of the mass of the entire mixture. For instance: if a bottle contains 40 grams of ethanol and 60 grams of water, then it contains 40% ethanol by mass. Commercial concentrated aqueous reagents such as acid and bases are often labeled in concentrations of weight percentage with the specific gravity also listed. In older texts and references this is sometimes referred to as weight-weight percentage (abbreviated as w/w).

Mass-volume percentage

Mass-volume percentage, (sometimes referred to as weight-volume percentage and often abbreviated as % m/v or % w/v) denotes the mass of a substance in a mixture as a percentage of the volume of the entire mixture. Mass-volume percentage is often used for solutions made from solid reagents. It is the mass of the solute in grams multiplied by one hundred divided by the volume of solution in milliliters.

Volume-volume percentage

Volume-volume percentage or % (v/v) describes the volume of the solute in mL per 100 mL of the resulting solution. This is most useful when a liquid - liquid solution is being prepared. For example, beer is about 5% ethanol by volume. This means every 100 mL beer contains 5 mL ethanol (ethyl alcohol).

Molarity

Molarity (M) denotes the number of moles of a given substance per litre of solution. For instance: 4.0 litres of liquid, containing 2.0 moles of dissolved particles, constitutes a solution of 0.5 M. Such a solution may be described as "0.5 molar." (Working with moles can be highly advantageous, as they enable measurement of the absolute number of particles in a solution, irrespective of their weight and volume. This is often more useful when performing stoichiometric calculations.). See molar solution for further information.

Molality

Molality (m) denotes the number of moles of a given substance per kilogram of solvent. For instance: 2.0 kilograms of solvent, containing 1.0 moles of dissolved particles, constitutes a molality of 0.5 mol/kg. Such a solution may be described as "0.5 molal." The advantage of molality is, it does not change with the temperature, as it deals with the mass of solvent rather than the volume of solution. Volume typically increases with increase in temperature resulting in decrease in molarity. Molality of a solution is always constant irrespective of the physical conditions like temperature and pressure.

Molinity

Molinity is a rarely-used term that denotes the number of moles of a given substance per kilogram of solution. For instance: imagine 2.0 kg of solvent, plus 1.0 mol of dissolved particles, weighs a total of 2.5 kg. The molinity of the solution is therefore 1 mol / 2.5 kg = 0.4 mol/kg. :Note: molarity and molinity are calculated using the volume of the entire solution, but molality is calculated using the mass of solvent only. :Warning: There may be confusion between above terms, which look and sound very similar; also, the abbreviations 'M' (denoting molarity) and 'm' (denoting molality) can be ambiguous. Special care should be exercised; if there is any risk of confusion, one should fully describe the measure being used.

Normality

Normality is a concept related to molarity, usually applied to acid-base solutions and reactions. For acid-base reactions, the equivalent is the mass of acid or base that can accept or donate exactly one mole of protons (H⁺ ions). Normality is also used for redox reactions. In this case the equivalent is the quantity of oxidizing or reducing agent that can accept or furnish one mole of electrons. Whereas molarity measures the number of particles per litre of solution, normality measures the number of equivalents per litre of solution. In practice, this simply means one multiplies the molarity of a solution by the valence of the ionic solute. A bit more complex for redox reactions. Note: The normality is always equal to, or greater than the molarity for acid-base reactions. However, for redox reactions the normality is typically equal to or less than the molarity.

Mole fraction

The mole fraction χ, chi (also called molar fraction) denotes the number of moles of solute as a proportion of the total number of moles in a solution. For instance: 1 mole of solute dissolved in 9 moles of solvent would have a mole fraction of 1/10 or 0.1.

Formal

The formal (F) is yet another measure of concentration similar to molarity. It is used rarely. It is calculated based on the formula weights of chemicals per litre of solution. The difference between formal and molar concentrations is that the formal concentration indicates moles of the original chemical formula in solution, without regard for the species that actually exist in solution. Molar concentration, on the other hand, is the concentration of species in solution. For example: if one dissolves sodium carbonate (Na₂CO₃) in a litre of water, the compound dissociates into the Na⁺ and CO₃^2- ions. Some of the CO₃^2- reacts with the water to form HCO₃^- and H₂CO₃. If the pH of the solution is low, there is practically no Na₂CO₃ left in the solution. So, although we have added 1 mol of Na₂CO₃ to the solution, it does not contain 1 M of that substance. (Rather, it contains a molarity based on the other constituents of the solution.) However, one can still say that the solution contains 1 F of Na₂CO₃.

"Parts-per" notation

The parts-per notation is used for extremely low concentrations. This is often used to denote the relative abundance of trace elements in the Earth's crust, trace elements in forensics or other analyses, or levels of pollutants in the environment.
- Parts per hundred (denoted by '%' and very rarely 'pph') - denotes one particle of a given substance for every 99 other particles. This is the common percent. 1 part in 10².
- Parts per thousand (denoted by '‰' [the per mil symbol], and occasionally 'ppt') denotes one particle of a given substance for every 999 other particles. This is roughly equivalent to one drop of ink in a cup of water, or one second per 17 minutes. 'Parts per thousand' is often used to record the salinity of seawater. 1 part in 10³.
- Parts per million ('ppm') denotes one particle of a given substance for every 999,999 other particles. This is roughly equivalent to one drop of ink in a 40 gallon drum of water, or one second per 280 hours. 1 part in 10⁶.
- Parts per billion ('ppb') denotes one particle of a given substance for every 999,999,999 other particles. This is roughly equivalent to one drop of ink in a canal lock full of water, or one second per 32 years. 1 part in 10⁹.
- Parts per trillion ('ppt') denotes one particle of a given substance for every 999,999,999,999 other particles. This is roughly equivalent to one drop of ink in an Olympic-sized swimming pool, or one second every 320 centuries. 1 part in 10¹².
- Parts per quadrillion ('ppq'?) denotes one particle of a given substance for every 999,999,999,999,999 other particles. This is roughly equivalent to a drop of ink in a medium-sized lake, or one second every 32,000 millennia. There are no known analytical techniques that can measure with this degree of accuracy; nevertheless, it is still used in some mathematical models of toxicology and epidemiology. 1 part in 10¹⁵. Warning: although 'ppt' is usually used to denote 'parts per trillion', it is also on occasion used to denote 'parts per thousand'. If there is any chance of ambiguity, one should describe the abbreviation in full. According to the U.S. National Institute of Standards and Technology (NIST) Guide for the Use of the International System of Units (SI), "the language-dependent terms part per million, part per billion, and part per trillion ... are not acceptable for use with the SI to express the values of quantities." [http://physics.nist.gov/Pubs/SP811/sec07.html#7.10.3] which lists examples of alternative expressions. Notes for clarity: :The indication given above is that parts per notation refers to numbers of particles (equivalent to moles), whereas in the last column of the chart below it is given by mass (grams per kilogram). Those using the notation need to state their usage to avoid confusion. :In atmospheric chemistry the parts per notation is commonly expressed with a v following, such as ppmv (or ppvm is some usages), to indicate parts per million by volume. In gases ppmv is equivalent to ppm by particles (Avogadro's law). This works fine for gases, but may have problems with cloud droplets and smoke or other atmospheric particulate matter.

Techniques used to determine concentration

- Spectrophotometry
- Chromatography
- Various titration methods

Table of concentration measures

Frequently used standards of concentration
Measurement	Notation	Generic formula	Typical units
Mass percentage	-	$\left ( \frac \right )$	%
Mass-volume percentage	-	$\left ( \frac \right )$	% though strictly %kg/L
Volume-volume percentage	-	$\left ( \frac \right )$	%
Molarity	M	$\left ( \frac \right )$	mol/L (or M)
Molinity	-	$\left ( \frac \right )$	mol/kg
Molality	m	$\left ( \frac \right )$	mol/kg (or m)
Molar fraction	χ (chi)	$\left ( \frac \right )$	(fraction)
Formal	F	$\left ( \frac \right )$	mol/L (or F)
Normality	N	$\left ( \frac \times valence\ of\ solute \right )$	N
Parts per hundred	% (or pph)	$\left ( \frac \right )$	da.g/kg
Parts per thousand	‰ (or ppt - )	$\left ( \frac \right )$	g/kg
Parts per million	ppm	$\left ( \frac \right )$	mg/kg
Parts per billion	ppb	$\left ( \frac \right )$	μg/kg
Parts per trillion	ppt -	$\left ( \frac \right )$	ng/kg
Parts per quadrillion	ppq	$\left ( \frac \right )$	pg/kg

- Although 'ppt' is usually used to denote 'parts per trillion', it is on occasion used for 'parts per thousand'. Sometimes 'ppt' is also used as an abbreviation for precipitate. Note (1) : The table above is described in terms of solvents and solutes; however the units given often also apply to other types of mixture. Note (2) : The use of billion, trillion, quadrillion above follows the short scale usage of these words. Category:Analytical chemistry ja:モル濃度

Living

:For other uses, see Life and Living Life is a multi-faceted concept. Life may refer to the ongoing process of which living things are a part, the period between the conception (or a point at which the entity can be considered to be an individualized being) and death of an organism, the condition of an entity that has been born (or reached the point in its existence at which it can be established to be alive) and has yet to die, and that which makes a living thing alive.

Defining the concept of life

How can one tell when an entity is a lifeform? It would be relatively straightforward to offer a practical set of guidelines if one's only concern were life on Earth as we know it (see biosphere), but as soon as one considers questions about life's origins on Earth, or the possibility of extraterrestrial life, or the concept of artificial life, it becomes clear that the question is fundamentally difficult and comparable in many respects to the problem of defining intelligence. Also, loosely speaking, some theories are grounded in the basic assumption that "ideas have a life of their own".

A conventional definition

In biology, a lifeform has traditionally been considered to be a member of a population whose members can exhibit all the following phenomena at least once during their existence: #Growth, full development, maturity #Metabolism, consuming, transforming and storing energy/mass; growing by absorbing and reorganizing mass; excreting waste #Motion, either moving itself, or having internal motion #Reproduction, the ability to create entities that are similar to, yet separate from, itself or consisting solely of entities that exhibit the quality of reproduction. #Response to stimuli - the ability to measure properties of its surrounding environment, and act upon certain conditions. This property is also called homeostasis.

Exceptions to the conventional definition

These criteria are not without their uses, but their disparate nature makes them unsatisfactory from a number of perspectives; in fact, it is not difficult to find counterexamples and examples that require further elaboration. For example, according to the above definition, one could say:
- (most) mules and people who are infertile cannot reproduce and thus would not qualify as lifeforms. Also worker bees and other organisms living in colonies would not qualify; only the queen and the drones (or the whole colony) can be considered 'alive'.
- Fire and stars could be considered lifeforms.
- A virus does not grow and cannot reproduce outside of a host cell and thus would not qualify as a lifeform. Many individual organisms are incapable of reproduction and yet are still considered to be lifeforms; see mules and ants for examples. This is because the term "lifeform" applies on the level of entire species or of individual genes. (For example, see kin selection for information about one way by which non-reproducing individuals can still enhance the spread of their genes and the survival of their species.) It is important to keep in mind the difference between a "lifeform" and "a being that is alive." One example of sterility does not render the rest of the species a non-lifeform, any more than one dead animal renders the rest of the species dead. Note also that the two cases of fire and stars fitting the definition of life can be simply remedied by defining metabolism in a more biochemically exact way. Fundamentals of Biochemistry by Donald Voet and Judith Voet (ISBN 0471586501) defines metabolism as follows: "Metabolism is the overall process through which living systems acquire and utilize the free energy they need to carry out their various functions. They do so by coupling the exergonic reactions of nutrient oxidation to the endergonic processes required to maintain the living state, such as the performance of mechanical work, the active transport of molecules against concentration gradients, and the biosynthesis of complex molecules." This definition, in use by most biochemists, makes it clear that fire is not alive, because fire releases all the oxidative energy of its fuel as heat. (Note: Actually, the definition does not help much at all, for it is circular. What we are looking for, after all, is a definition of "living entity." We agreed that part of the definition is "capable of metabolism." We then tried to define "metabolism" in order to get clear on which entities are capable of it and which not. But the definition of "metabolism" just offered is in terms of living systems, and those are exactly what we are trying to define!) This could also be remedied by adding the requirement of locality, where there is an obvious structure that delineates the spatial extension of the living being, such as a cell membrane. A conceptual problem with saying that fire is life is that it collapses the distinction between "growth" and "reproduction." It is possible to think of a spreading flame as either growing or reproducing, but what would it mean to say that the same act is both growth and reproduction? Viruses reproduce, flames grow, some software programs mutate and evolve, future software programs will probably evince (even high-order) behavior, machines move, and some form of proto-life consisting of metabolizing cells without the ability to reproduce presumably existed. Still, some would not call these entities alive. Generally, all five characteristics are required for a population to be considered a lifeform.

Other definitions

Biologists who are content to focus on terrestrial organisms often note some additional signs of life, including these: # Living organisms contain molecular components such as: carbohydrates, lipids, nucleic acids, and proteins. # Living organisms require both energy and matter in order to continue living. # Living organisms are composed of at least one cell. # Living organisms maintain homeostasis for some period of time. # Species of living organisms will evolve. All life on Earth is based on the chemistry of carbon compounds. Some assert that this must be the case for all possible forms of life throughout the universe; others describe this position as 'carbon chauvinism'. The systemic definition is that living things are self-organizing and autopoietic (self-producing). These objects are not to be confused with dissipative structures (e.g. fire). Variations of this definition include:
- Francisco Varela and Humberto Maturana's definition of life (also widely used by Lynn Margulis) as an autopoietic (self-producing), water based, lipid-protein bound, carbon metabolic, nucleic acid replicated, protein readout system
- "a system of inferior negative feedbacks subordinated to a superior positive feedback" ([http://www.mol.uj.edu.pl/~benio/cyber_def_life.pdf J. theor Biol. 2001])
- Tom Kinch's definition of life as a highly organized auto-cannibalizing system naturally emerging from conditions common on planetary bodies, and consisting of a population of replicators capable of mutation, around each set of which a homeostatic metabolizing organism, which actively helps reproduce and/or protect the replicator(s), has evolved
- Stuart Kauffman's definition of life as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle
- Robert Pirsig's definition of life, found in his book Lila: An Inquiry into Morals, as that which maximizes its range of possible futures, in other words, that which makes decisions that result in the most future choices, or that which strives to keep its options open.
- A system converting entropy to negentropy, using flow of energy. Other definitions:
- That which seeks to continue its own existence (attributed to Clifford A. Schaffer).
- A self-replicating system that evolves through mutation.

Descent with modification: a "useful" characteristic

A useful characteristic upon which to base a definition of life is that of descent with modification: the ability of a life form to produce offspring that are like its parent or parents, but with the possibility of some variation due to chance. Descent with modification is sufficient by itself to allow evolution, assuming that the variations in the offspring allow for differential survival. The study of this form of heritability is called genetics. In all known life forms (assuming prions are not counted as such), the genetic material is primarily DNA or the related molecule, RNA. Another exception might be the software code of certain forms of viruses and programs created through genetic programming, but whether computer programs can be alive even by this definition is still a matter of some contention.

Origin of life

Main article: Origin of life There is no truly "standard" model of the origin of life, but most currently accepted scientific models build in one way or another on the following discoveries, which are listed roughly in order of postulated emergence: #Plausible pre-biotic conditions result in the creation of the basic small molecules of life. This was demonstrated in the Urey-Miller experiment. #Phospholipids spontaneously form lipid bilayers, the basic structure of a cell membrane. #Procedures for producing random RNA molecules can produce ribozymes, which are able to produce more of themselves under very specific conditions. There are many different hypotheses regarding the path that might have been taken from simple organic molecules to protocells and metabolism. Many models fall into the "genes-first" category or the "metabolism-first" category, but a recent trend is the emergence of hybrid models that do not fit into either of these categories.

The possibility of extraterrestrial life

Main articles: Extraterrestrial life, Astrobiology As of 2005, Earth is the only planet in the universe known by humans to support life. The question of whether life exists elsewhere in the universe remains open, but analyses such as the Drake equation have been used to estimate the probability of such life existing. There have been a number of claims of the discovery of life elsewhere in the universe, but none of these have yet survived scientific scrutiny. Today, the closest that scientists have come to finding extraterrestrial life is fossil evidence of possible bacterial life on Mars (via the ALH84001 meteorite). Searches for extraterrestrial life are currently focusing on planets and moons believed to possess liquid water, at present or in the past. Recent evidence from the NASA rovers Spirit and Opportunity supports the theory that Mars once had surface water. See Life on Mars for further discussion. Jupiter's moons are also considered good candidates for extraterrestrial life, especially Europa, which seems to possess oceans of liquid water. Other highly speculative and somewhat doubtful places for present or past life include the atmosphere of Venus, Titan cryovolcanoes, or even Enceladus.

References

- Kauffman, Stuart. The Adjacent Possible: A Talk with Stuart Kauffman. Retrieved Nov. 30, 2003 from [http://www.edge.org/3rd_culture/kauffman03/kauffman_index.html]

External links

- [http://www.lifetheory.com Express your theory and meaning of life]
- [http://www.edge.org/3rd_culture/kauffman03/kauffman_index.html "The Adjacent Possible: A Talk with Stuart Kauffman"]
- [http://www.quotesandpoem.com/poems/SelectedPoetryTopic/Life Poems and Quotes about life and living]
- [http://www.angelfire.com/linux/vjtorley/ Animals and other living things: their interests, mental capacities and moral entitlements]
- [http://tolweb.org/tree?group=life Tree of Life Web Project - Life on Earth]
- [http://plato.stanford.edu/entries/life/ Stanford Encyclopedia of Philosophy entry]
- [http://web.archive.org/web/20041030074958/http://people.cornell.edu/pages/tg21/DHB.html The Deep Hot Biosphere Theory (Thomas Gold)] Category:Biology ja:生命 ko:생명 ms:Benda hidup simple:Life

Organism

In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. The origin of life and the relationships between its major lineages are controversial. Two main grades may be distinguished, the prokaryotes and eukaryotes. The prokaryotes are generally considered to represent two separate domains, called the Bacteria and Archaea, which are not closer to one another than to the eukaryotes. The gap between prokaryotes and eukaryotes is widely considered a major missing link in evolutionary history. Two eukaryotic organelles, namely mitochondria and chloroplasts, are generally considered to be derived from endosymbiotic bacteria. The phrase complex organism describes any organism with more than one cell.

Organizational terminology

Biological Organization

Viruses

Viruses are not typically considered to be organisms because they are not capable of independent reproduction or metabolism. However, according to the United States Code, they are considered to be microorganisms in the sense of biological weaponry and malicious use. This controversy is problematic, though, since some parasites and endosymbionts are incapable of independent life either. Although viruses do have enzymes and molecules characteristic of living organisms, they are incapable of surviving outside a host cell and most of their metabolic processes require a host and its 'genetic machinery'. The origin of such parasites is uncertain, but it appears most likely that they are derived from their host.

Life span

One of the basic parameters of organism is its life span. Some animals live as short as one day, while some plants can live thousands of years. Aging is important when determining life span of most organisms, bacterium, a virus or even a prion.

External links

- [http://news.bbc.co.uk/1/hi/sci/tech/944790.stm BBCNews: 27 September, 2000, When slime is not so thick] Citat: "...It means that some of the lowliest creatures in the plant and animal kingdoms, such as slime and amoeba, may not be as primitive as once thought...."
- [http://www.spaceref.com/news/viewpr.html?pid=4742 SpaceRef.com, July 29, 1997: Scientists Discover Methane Ice Worms On Gulf Of Mexico Sea Floor]
- [http://www.science.psu.edu/iceworms/iceworms.html The Eberly College of Science: Methane Ice Worms discovered on Gulf of Mexico Sea Floor] download Publication quality photos
- [http://www.sb-roscoff.fr/Ecophy/PDF/00-Fisher-NatWis.pdf Artikel, 2000: Methane Ice Worms: Hesiocaeca methanicola. Colonizing Fossil Fuel Reserves]
- [http://www.spaceref.com/news/viewnews.html?id=339 SpaceRef.com, May 04, 2001: Redefining "Life as We Know it"] Hesiocaeca methanicola In 1997, Charles Fisher, professor of biology at Penn State, discovered this remarkable creature living on mounds of methane ice under half a mile of ocean on the floor of the Gulf of Mexico.
- [http://news.bbc.co.uk/1/hi/sci/tech/2585235.stm BBCNews, 18 December, 2002, 'Space bugs' grown in lab] Citat: "...Bacillus simplex and Staphylococcus pasteuri...Engyodontium album...The strains cultured by Dr Wainwright seemed to be resistant to the effects of UV - one quality required for survival in space...."
- [http://news.bbc.co.uk/1/hi/sci/tech/3003946.stm BBCNews, 19 June, 2003, Ancient organism challenges cell evolution] Citat: "..."It appears that this organelle has been conserved in evolution from prokaryotes to eukaryotes, since it is present in both,"..."
- [http://www.anselm.edu/homepage/jpitocch/genbios/bi04syllabsu03.html Interactive Syllabus for General Biology - BI 04, Saint Anselm College, Summer 2003]
- [http://www.personal.psu.edu/users/j/s/jsf165/Bio110.html Jacob Feldman: Stramenopila]
- [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Root NCBI Taxonomy entry: root] (rich)
- [http://www.anselm.edu/homepage/jpitocch/genbios/surveybi04.html Saint Anselm College: Survey of representatives of the major Kingdoms] Citat: "...Number of kingdoms has not been resolved...Bacteria present a problem with their diversity...Protista present a problem with their diversity...",
- [http://www.species2000.org/ Species 2000 Indexing the world's known species]. Species 2000 has the objective of enumerating all known species of plants, animals, fungi and microbes on Earth as the baseline dataset for studies of global biodiversity. It will also provide a simple access point enabling users to link from here to other data systems for all groups of organisms, using direct species-links.
- [http://www.abc.net.au/science/news/enviro/EnviroRepublish_828525.htm The largest organism in the world may be a fungus carpeting nearly 10 square kilometers of an Oregon forest, and may be as old as 8500 years.]
- [http://tolweb.org/tree/phylogeny.html The Tree of Life]. zh-min-nan:Seng-bu̍t ko:생물 ja:生物 th:สิ่งมีชีวิต

Illness

Illness can be a synonym for disease or it can be a person's perception of having poor health. Disease is an actual physical, pathophysiological process which can cause an abnormal condition of the body or mind. Illness and disease are not necessarily the same. Most people who have a disease will feel they have an illness, while others will feel perfectly healthy. A third group (although small) may claim illness although they do not actually have a disease. People could have dangerously high blood pressure (hypertension) and be in danger of having a fatal heart attack or stroke, yet they feel perfectly well and believe they do not have an illness. The biopsychosocial model draws a distinction between the actual pathological processes that cause disease, and the patient's perception of their health and the effects on it, called the illness. Category:Medical terms Category:Personal life

Death

:For other uses, see Death (disambiguation) or Dead (disambiguation). Death is the cessation of physical life in a living organism or the state of the organism after that event.

Interpretations of "death"

In almost all societies, death has one or several symbols associated with it. Common symbols of death in Western cultures include the grim reaper and the color black; conversely, in certain Eastern cultures, the color white is considered symbolic of death. The grave is a metonym for death. Biologically, death can occur to wholes, to parts of wholes, or to both. For example, it is possible for individual cells and even organs to die, and yet for the organism as a whole to continue to live; many individual cells can live for only a short time, and so most of an organism's cells are continually dying and being replaced by new ones. Conversely, when organisms die their cells can live for some time afterward. Organs, for instance, can be removed for transplantation. They must be removed and transplanted quickly, or they too will soon die without the support of their host. Rarely, cell cultures can be "immortal" as in the case of Henrietta Lacks' HeLa cell line. Fingernails and hair appear to grow after a person's death, as, due to bodily dehydration, the flesh pulls away from the hair and nails. In ancient times, this led to confusion about whether a body was actually dead, and added to the myth of vampires. Irreversibility is often cited as a key feature of death. By definition, a dead organism cannot be brought back to life; if it were to be, that would indicate that it had never been dead. Nonetheless, many people do not believe that death is necessarily irreversible; thus some have a religious belief in bodily or spiritual resurrection, while others have hope for the eventual prospects of cryonics or other technological means of reversing what is currently thought of as death. It has been hypothesized that a limited lifespan is a consequence of evolution not selecting for extreme longevity in most species, as evolutionary selection only need apply to the organism up to the point of reproduction; after that, except for caring for kin, the continued existence of an individual can have little effect on the survival of its gene line. A common assumption is that the Second Law of Thermodynamics dictates that all complex systems must eventually deteriorate, so it is not likely that any species could ever be immortal. However, this aspect of the Second Law of Thermodynamics only applies to closed systems, which organisms are not.

Ways of defining human death: medical, religious, and legal

Human death can be defined by three dramatically different but overlapping domains: medical, religious, and legal. These different domains and their importance have evolved over time and can vary from person to person. So when talking about death, it is important to differentiate which domain we are speaking of and to have a general understanding of how each defines death. There are various ways of defining medical death. Early in western culture, death was connected to the heart first and then later the lungs. When these stopped working, a person was dead. It was sometime later that the brain came into the definition. In 1963 a device called an electroencephalogram (EEG) was invented that could very accurately measure the electrical output of the brain. The test showed that when the machine registered zero electrical output from a person's brain (also known as a flat EEG) for 36 hours, the patient could be considered dead. We now know that a person can continue to be medically alive until their brain stem dies. Patients in a persistent vegetative state still have an active brain stem. Legally, a person can be pronounced dead in three different ways. By far the most common is pronouncement by a medical doctor. The second most common is pronouncement by a coroner or a state medical examiner. The third way a person can be pronounced legally dead is by the courts; after a person has disappeared for some time, the courts will pronounce them dead so that their property can be distributed appropriately. A death certificate is a legal document which states how and when a person died, and who pronounced them dead. In religous terms, death is believed to refer to the departure from the body of the soul, or essence.

When is a person dead?

Identifying the exact moment of death is important for a number of reasons. It allows for the correct time on death certificates, and helps ensure that a person's will is enacted only after they are truly deceased. In particular, identifying the moment of death is important in cases of transplantation, as organs must be harvested as quickly as possible after death. Historically, attempts to define the exact moment of death have been problematic. Death was once defined as the cessation of heartbeat (cardiac arrest) and of breathing, for example, but the development of CPR and early defibrillation posed a challenge: either the definition of death was incorrect, or techniques had been discovered that really allowed one to reverse death (because, in some cases, breathing and heartbeat can be restarted). Generally, the first option was chosen. (Today this definition of death is known as "clinical death".) Today, where a definition of the moment of death is required, doctors and coroners usually turn to "brain death" or "biological death": people are considered dead when the electrical activity in their brain ceases (cf. persistent vegetative state). It is presumed that a stoppage of electrical activity indicates the end of consciousness. Brain activity is a necessary condition to legal personhood, and, perhaps with the exception of the fetus, it is a sufficient condition for legal personhood. "It appears that once brain death has been determined … no criminal or civil liability will result from disconnecting the life-support devices." Dority v. Superior Court of San Bernardino County, 193 Cal.Rptr. 288, 291 (1983) However, those maintaining that only the neo-cortex of the brain is necessary for consciousness sometimes argue that only electrical activity there should be considered when defining death. In most places the more conservative definition of death (cessation of electrical activity in the whole brain, as opposed to just in the neo-cortex) has been adopted (for example the Uniform Determination Of Death Act in the United States). In 2005, the case of Terri Schiavo brought the question of brain-death and artificial sustainment to the front of American politics. However, in all cases the common cause of death is anoxia. Even in these cases, the determination of death can be difficult. EEGs can detect spurious electrical impulses when none exists, while there have been cases in which electrical activity in a living brain has been too low for EEGs to detect. Because of this, hospitals often have elaborate protocols for determining death involving EEGs at widely separated intervals. Medical history contains many anecdotal references to people being declared dead by physicians and coming back to life, sometimes days later in their own coffin or when embalming procedures are about to get underway. Stories of people actually being buried alive (which must assume embalming has not occurred) led at least one inventor in the early 20th century to design an alarm system that could be activated from within the coffin. Because of the difficulties in determining death, under most emergency protocols, a first responder is not authorized to pronounce a patient dead; some EMT training manuals, for example, specifically state that a person is not to be assumed dead unless there are clear and obvious indications that death has occurred, such as mortal decapitation, rigor mortis (the stiffening of the body), livor mortis (blood pooling in the lowest part of the body), decomposition, or incineration. If there is any possibility of life and in the absence of a do not resuscitate order, emergency workers must begin rescue and not end it until a patient has been brought to a hospital to be examined by a physician. This frequently leads to situation of a patient being pronounced dead on arrival.

The process of dying

Cell death

A. Normal cellular function :1. Production of energy required for vital cellular processes :2. Production of enzymatic and structural protein :3. Maintenance of chemical and osmotic homeostasis of cell :4. Cell reproduction B. Needs of cell :1. Oxygen, phosphate, calcium :2. Nutritional substrates :3. ADP - needed to produce ATP :4. Intact cell membranes :5. Steady state of activity enhances 02 consumption

Physiological changes during the process of dying

A. Events leading to death: :1. Brain ceases to supply information vital for controlling ventilation, heart rhythm, and/or vasodilation :2. Lungs unable to supply 0₂ exchange with blood stream :3. Heart and blood vessels unable to maintain adequate circulation of blood to vital tissues B. Cerebrovascular system: :1. Hemorrhage :2. Pump failure :3. Decreased CO₂ leads to decreased PCO2 leads to Cheyne-Stokes respiration C. CNS problems: :1. Infection :2. Blood vessel disruption :3. Malignant tumors :4. Metabolic changes ::a. Renal failure ::b. Hepatic failure ::c. Pancreatic failure D. CNS decompensation: :1. Early signs: ::a. Sluggish pupils :::(1) Non reactive :::(2) Dilated and fixed - drugs also affect this ::b. Confusion ::c. Inability to orient :2. Later signs: ::a. Lethargy ::b. Decreased ability to perform simple cognitive functions ::c. Attention only by tactile, auditory or visual stimuli :3. Late signs: ::a. Stupor, sleep ::b. Withdrawal of purposeless involvement to stimuli without wakefulness or arousal :4. Semicomatose - movement only with pain :5. Deep coma - no response E. Respiratory system: :1. CBF :2. COPD :3. Infections :4. Cancer metutasis :Changes after death: :A. Body cools 1.5 degrees/hr :B. Rigor mortis begins prior to decomposition and liver mortis begins with death :C. Rigor mortis: ::1. Muscles gradually become hard due to decreased ATP and lactic acidosis within muscle febrils ::2. Begins 2-4 hours after death but may be sooner ::3. May disappear 9-12 hours in hot climate :D. Liver mortis: ::1. Body becomes distended ::2. Skin color changes from green to purple to black ::3. Dependent areas fust due to pooling of blood ::4. Seen within 2 hours of death, maximum at 8-12 hours

Signs of approaching death

When death is imminent

• Physical death is a progressive process, during which there are some signs that usually indicate that death is imminent. Not all of the following changes occur, nor do they necessarily occur in any particular order, as the body shuts down during the dying process. In general, the following information may help anticipate and understand changes that appear as an individual approaches death and is “actively dying.” • The dying individual may become increasingly tired and sleepy, and may be difficult to arouse. • The dying individual may become confused much of the time and may no longer recognize familiar persons, places, or objects. • Hearing and vision may become impaired, and speech may be slurred, difficult to understand, or nonsensical. • A few patients become restless or very anxious and move about frequently in the bed, pull at the bed clothes or bedding (linen clutch), and reach out. • The person may hallucinate, seeing things or people which may not appear to anyone else. • Less nourishment will be required, and the person’s intake of food and water will diminish. Difficulty in swallowing (dysphagia) may also occur. • The person may sweat profusely. • The dying individual may lose control of his/her urine or bowels ( incontinence), necessitating that the dying individual be kept especially clean and dry in order to prevent bed sores (decubitis ulcers). • Urination may become darker and diminish or stop. • The mouth of the dying individual may become dry, and then secretions may accumulate in the back of the throat. Breathing may become noisy because of the gurgling or rattling of the secretions in the mouth or chest (“death rattle”). • The pattern of breathing may change; become slower or faster, deeper or shallower, or irregular. Often the patient will have periods of rapid breathing followed by periods in which breathing is very slow or is even absent for as long as 15 seconds. • The legs, and then arms, may become cold and nonreflexive as the circulation slows down. • The skin may be pale or mottled, and some parts, particularly the underside of the body, may become a dark color as the blood pools, usually a deep blue or purple.

When death occurs

• Breathing ceases entirely. • Heartbeat and pulse stop. • The person is entirely unresponsive to stimulus. • The eyes may be fixed in directions. The pupils are dilated and fixed to light. The eyelids may be open or closed. • A loss of control of urine and/or bowels may occur. • The person becomes progressively mottled and cold and stiff (known as rigor mortis) • The skin may become pale; there may be signs of blood buildup on the side the person is laying on.

Cause of death in the United States

The cause of death varies by area and age group. In 2002 in the U.S. the top 10 causes of death were:
- Heart Disease: 696,947
- Cancer: 557,271
- Stroke: 162,672
- Chronic lower respiratory diseases: 124,816
- Accidents (unintentional injuries): 106,742
- Diabetes: 73,249
- Influenza/Pneumonia: 65,681
- Alzheimer's disease: 58,866
- Nephritis, nephrotic syndrome, and nephrosis: 40,974
- Septicemia: 33,865

Other notable causes of death in the United States (2002)

- Murder: 16,110
- Execution: 71
- Intentional Abortion: 1,293,000
- Note that there is much debate as to when a fetus should be considered "human." The death of a human zygote — a one-celled combination of a sperm and an egg — is counted by some as the death of a human, and by others as simply the death of a cell. The above number would apparently include abortions to save the life of the mother, abortions of obviously highly defective fetuses, and abortions of fetuses unlikely to reach term. Statistical data from [http://www.cdc.gov/nchs/fastats/lcod.htm U.S. Department of Health & Human Services] [http://www.deathpenaltyinfo.org/ Death Penalty Information Center] [http://www.nrlc.org/abortion/facts/abortionstats.html National Right To Life], and [http://www.agi-usa.org/media/presskits/2005/06/28/abortionoverview.html The Alan Guttmacher Institute]

What happens to humans after death?

The second question is of what, apart from the cessation of metabolism and the onset of physiological processes of decay, happens, especially to humans, during and after death (or "once dead", thinking of death as a permanent state). In particular, there is the question of what becomes of consciousness or the soul. Such questions are of long standing, and belief in an afterlife (such as an underworld), or in reincarnation, are common and ancient. The belief that any and all consciousness ceases to exist at death, and that death ("after-life") itself is ultimately the exact same experience as prior to conception ("before life"), is common in atheism/agnosticism. Conversely, religious belief in and information about an afterlife is a consolation in connection with the death of a beloved one or the prospect of one's own death. On the other hand, fear of hell or other negative consequences may make death worse. Human contemplation about death is an important motivation for the development of organized religion. Traditions exist across most cultures to mourn the death of loved ones. Many archaeologists feel that the careful burials among Homo neanderthalensis, where ochre ornamented bodies were laid in carefully dug graves, is evidence of ritualised burial. This may indicate early religious belief which, furthermore, might include a concept of an afterlife.

Physiological consequences of human death

For the human body, the physiological consequences of death follow a recognized sequence through early changes into bloating, then decay to changes after decay and finally skeletal remains. The changes in the immediate post-death stage have received the most attention for two reasons—firstly it is the stage mostly likely to be seen by the living and secondly because of the research of forensics in potential crimes. Soon after death (15–120 minutes depending on various factors), the body begins to cool (algor mortis), becomes pallid (pallor mortis), and internal sphincter muscles relax, leading to the release of urine, feces, and stomach contents if the body is moved. The blood moves to pool in the lowest parts of the body, livor mortis (dependent lividity), within 30 minutes and then begins to coagulate. The body experiences muscle stiffening (rigor mortis) which peaks at around 12 hours after death and is gone in another 24, depending on temperature. Within a day, the body starts to show signs of decomposition (decay), both autolytic changes and from 'attacking' organisms—bacteria, fungi, insects, mammalian scavengers, etc. Internally, the body structures begin to collapse, the skin loses integration with the underlying tissues, and bacterial action creates gases which cause bloating and swelling. The rate of decay is enormously variable; a body can be reduced to skeletal remains in days, or remain largely intact for thousands of years.

Settlement of dead human bodies

In most cultures, before the onset of significant decay, the body undergoes some type of ritual disposal, usually either cremation or deposition in a tomb that is often a hole in the ground called a grave, but may also be a sarcophagus, crypt, sepulchre, or ossuary, a mound or barrow, or a monumental surface structure such as a mausoleum (exemplified by the Taj Mahal). In Tibet, one method of corpse disposal is sky burial, which involves placing the body of the deceased on high ground (a mountain) and leaving it for birds of prey to dispose of. Sometimes this is because in some religious views, birds of prey are carriers of the soul to the heavens, but at other times this simply reflects the fact that when terrain (as in Tibet) makes the ground too hard to dig, there are few trees around to burn and the local religion (Buddhism) believes that the body after death is only an empty shell, there are more practical ways of disposing of a body, such as leaving it for animals to consume. On the other hand, in certain cultures, efforts are made to retard the decay processes before burial (resulting even in the retardation of decay processes after the burial), as in mummification or embalming. This happens during or after a funeral ceremony. Many funeral customs exist in different cultures. In some fishing or navy communities, the body is sent into the water aquatic burial. Several mountain villages have a tradition of hanging the coffin in woods. A new alternative is ecological burial. This is a sequence of deep-freezing, pulverisation by vibration, freeze-drying, removing metals, and burying the resulting powder, which has 30% of the body mass. Space burial is also talked about, using rocket to launch part of the cremated body. Graves are usually grouped together in a plot of land called a cemetery or graveyard, and burials can be arranged by a funeral home, mortuary , undertaker or by a religious body such as a church or (for some Jews) the community's Burial Society, a charitable or voluntary body charged with these duties.

Personification of death

Main article: Death (personification) Death is also a mythological figure who has existed in popular culture since the earliest days of storytelling. The traditional Western image of Death, known as the Grim Reaper - usually resembling a skeleton, wearing black robes and carrying a scythe - is employed on a tarot card and in various television shows and films. Some examples:
- Death is a major character in the Discworld series by Terry Pratchett.
- Humorous depictions of Death, often with a Grim Reaper-esque feel, are common during the Día de los Muertos in Mexico, especially in the state of Michoacán.
- An unusual personification of Death appears in Neil Gaiman's Sandman graphic novels.
- In Ingmar Bergman's The Seventh Seal, a knight plays a game of chess against Death.
- Death is also portrayed as a Grim Reaper-esque character in TV shows such as Family Guy and video and computer games such as The Sims.
- In the film, Meet Joe Black, a remake of Death Takes a Holiday, Death inhabits the body of a young man to experience life firsthand.
- In the film, Bill & Ted's Bogus Journey, Death is the bassist for Wyld Stallyns.
- In the TV series Dead Like Me, the main characters are all Grim Reapers as part of a post-life bureaucracy.
- The series Touched by an Angel featured the Angel of Death as a regular character, depicted as a kindly, soft-spoken man in his mid-30s.
- The Angel of Death also appeared in the show Charmed as a man that appeared before those who had died to take them to the afterlife. He was neither good nor evil.
- Death is also a recurring character in the Castlevania video games. He is usually described as Dracula's servant, and is therefore evil. He is almost always a boss, and appears usually near the end of the game. He uses the scythe, and often transforms into more hideous forms.
- Death 'stalks' people who avoided their demise in the Final Destination series.
- Death appears as a character in a sketch in the Monty Python film The Meaning of Life.
- In the cartoon Futurama, Death is represented by the "Sunset Squad", a group of robots who take people away to an unknown destination when they reach the age of 160.
- In the book On a Pale Horse the main character becomes Death himself after killing the previous Death.

External links

- [http://www.disastercenter.com/cdc/111riska.html Deaths and death rates for the 10 leading causes of death in specified age groups: United States, preliminary 1996]
- [http://www.nsc.org/lrs/statinfo/odds.htm Odds of dying due to various injuries or accidents] Source: National Safety Council, United States, 2001
- [http://www.veda.harekrsna.cz/encyclopedia/dying.htm Dying, Yamaraja and Yamadutas + terminal restlessness] (Vedic/Hindu view)
- [http://www.quranichealing.com/bp.asp?caid=65 Death & Dying in Islam]What does a man feel at the time of death? and Is death something to be feared?
- [http://www.zyworld.com/jamus/LifeCycle.htm The Cycle of Life] In context of the page New Age of Aquarius.
- [http://samvak.tripod.com/death.html Death, life, and personal identity] In regard to memetics.
- [http://www.quotesandpoem.com/poems/SelectedPoetryTopic/Death Poems on Death and Dying]
- [http://www.answersingenesis.org/docs2002/death_suffering.asp Why is there death and suffering?] From a creationist point of view.
- [http://www.ogrish.com Deaths and death scenes. WARNING: very explicit]
- [http://www.elijahwald.com/origin.html George Wald: The Origin of Death] A biologist explains life and death in different kinds of organisms in relation to evolution.
- [http://plato.stanford.edu/entries/death/ Stanford Encyclopedia of Philosophy entry on death]
- [http://www.deathclock.com Death Clock] A little joke telling how much time remains for your death
- [http://www.autopsyvideo.com www.autopsyvideo.com] - This site offers documentaries about autopsy, one produced with the cooperation of the Los Angeles County Coroner's Office.
- [http://www.chabad.org/article.asp?AID=281541 The Jewish Way in Death and Mourning] By Maurice Lamm Category:Biology
- ms:Ajal ja:死 simple:Death

Drug

Drug may refer to:
- Medication
- Psychoactive drug
- substances used for recreational drug use
- substances used in drug abuse
- Hard and soft drugs
- A drug or demon in ancient Vedic Hinduism, from the Vedic Sanskrit root druh = "be hostile"
- The Drûg or Drúedain, a race of Men from Middle-earth in the fiction of J. R. R. Tolkien

Poison

In the context of biology, poisons are substances that cause injury, illness, or death to organisms, usually by chemical reaction or other activity on the molecular scale. Some poisons are also toxins, usually referring to naturally produced substances that kill rapidly in small quantities, such as the bacterial proteins that cause tetanus and botulism. A distinction between the two terms is not always observed, even among scientists. Animal toxins that are delivered subcutaneously (e.g. by sting or bite) are also called venom. In normal usage, a poisonous organism is one that is harmful to consume, but a venomous organism uses poison to defend itself while still alive. A single organism can be both venomous and poisonous.The derivative forms "toxic" and "poisonous" are synonymous. Within chemistry and physics, a poison is a substance that obstructs or inhibits a reaction, for example by binding to a catalyst. Poisons have been known to be symbolized by the skull and crossbones (shown beside), although since this attracts children (being linked to pirates) it is gradually being replaced by Mr. Yuk in the United States. In the United Kingdom and some parts of Europe, irritant poisons are symbolised by a large "X" on an orange background. Deliberate application of poison has throughout the ages been used as method of murder, suicide and execution. As a method of execution, the poison can be administered as ingested, as the ancient Athenians did (see Socrates), breathed, such as carbon monoxide or hydrogen cyanide (see gas chamber) or intravenously (see lethal injection). Many non-English languages call lethal injection with their corresponding words for "poison shot".

Biological poisoning

Contact or absorption of poisons can cause rapid death or impairment. Agents that act on the nervous system can paralyze in seconds or less, and include both biologically derived neurotoxins and so-called nerve gases, which may be synthesized for warfare or industry. Inhaled or ingested cyanide as used as method of execution on US gas chambers almost instantly starves the body of energy by poisoning mitochondria and the synthesis of ATP. Intravenous injection of an unnaturally high concentration of potassium chloride, such as in the execution of prisoners in parts of the United States, quickly stops the heart by eliminating the cell potential necessary for muscle contraction. Such rapid reactions are often called acute poisoning. Most (but not all) pesticides are created to act as poisons to target organisms, although acute or less observable chronic poisoning can also occur to non-target organism, including the humans who apply the pesticides and other beneficial organisms. A poison may also act slowly. This is known as chronic poisoning and is most common for poisons that bioaccumulate. Examples of these types of poisons are mercury and lead. Many substances regarded as poisons are toxic only indirectly. An example is "wood alcohol" or methanol, which is not poisonous itself, but is chemically converted to toxic formaldehyde in the liver. Many drug molecules are made toxic in the liver, and the genetic variability of certain liver enzymes makes the toxicity of many compounds differ between one individual and the next. The study of the symptoms, mechanisms, treatment and diagnosis of biological poisoning is known as toxicology. Exposure to radioactive substances can produce radiation poisoning, an unrelated phenomenon.

Classification of biological poisons by mechanism

Corrosives

Corrosives mechanically damage biological systems on contact. Both the sensation and injury caused by contact with a corrosive resembles a burn injury.

Acids

Strong inorganic acids, such as concentrated sulfuric acid, nitric acid or hydrochloric acid, destroy any biological tissue with which they come in contact within seconds.

Bases

Strong inorganic bases, such as lye, gradually dissolve skin on contact but can cause serious damage to eyes or mucous membranes much more rapidly. Ammonia is a far weaker base than lye, but has the distinction of being a gas and thus may more easily come into contact with the sensitive mucous membranes of the respiratory system. Quicklime, which has household uses, is a particularly common cause of poisoning. Some of the light metals, if handled carelessly, can not only cause thermal burns, but also produce very strongly basic solutions in sweat.

Oxidizers

Poisons of this class are generally not very harmful to higher life forms such as humans (for whom the outer layer of cells are more or less disposable), but lethal to microorganisms such as bacteria. Typical examples are ozone and chlorine, either of which is added to nearly every municipal water supply in order to kill any harmful microorganisms present. All halogens are strong oxidizing agents, fluorine being the strongest of all. :See also: Free radical

Reducing agents

The most notable substance in this class is phosphorus.

Metabolic poisons (energy)

Metabolic poisons act by adversely disrupting the normal metabolism of an organism.

Specific biochemical inhibitors

- By far the most notable substance in this class is carbon monoxide, which blocks the ability of red blood cells to transport oxygen.
- Fluoroacetate blocks a vital step in the citric acid cycle.
- Cyanide bonds with an enzyme involved in ATP production.
- Rotenone - disrupts electron transport in cellular respiration
- Antimycin - disrupts electron transport in cellular respiration
- Malonate - inhibits cellular respiration
- 2,4-Dinitrophenol - disrupts cellular proton gradient

Heavy metals

A common trait shared by heavy metals is the chronic nature of their toxicity (a notable exception would be bismuth, which is considered entirely non-toxic). Low levels of heavy metal salts ingested over time accumulate in the body until toxic levels are reached. Heavy metals are generally far more toxic when ingested in the form of soluble salts than in elemental form. For example, metallic mercury passes through the human digestive tract without interaction and is commonly used in dental fillings—even though mercury salts and inhaled mercury vapor are highly toxic. Notable examples:
- arsenic (see arsenic poisoning)
- antimony
- barium
- cadmium
- chromium
- lead
- mercury
- thallium
- uranium
- beryllium (a highly but subtly toxic light metal)

Neurotoxins

Neurotoxins interfere with nervous system functions and often lead to near-instant paralysis followed by rapid death. They include most spider and snake venoms, as well as many modern chemical weapons. One class of toxins of interest to neurochemical researchers are the various cone snail toxins known as conotoxins.

Anticholinesterases

- Fasciculin

Acetylcholine antagonists

- Curare
- Pancuronium

Cell membrane disrupters

Others

- Nicotine - not strictly a neurotoxin, but capable in large doses of causing heart attack

Teratogens (birth defects)

- Thalidomide

Mutagens (DNA damage)

- Ultraviolet Rays - Long term exposure may cause skin cancer such as Melanoma
- Other Ionizing Radiation - Causes radiation sickness and cancer
- ethidium bromide

Carcinogens (cancer)

A carcinogen is a chemical substance which is believed to cause cancer. There are an enormous variety of possible carcinogens. Some of the better known or more controversial examples are listed below.
- Some artificial sweeteners (e.g. Aspartame and Saccharin) have been alleged to be carcinogenic or neurotoxic (however these research behind these claims is highly controversial and inconclusive; the FDA believes aspartame is safe for humans in dietary doses).
- Asbestos - a widely used insulating material that causes mesothelioma and other cancers especially in the respiratory tract.
- Benzene (lab solvent, used in various chemical reactions).
- Carbon tetrachloride (formerly used in fire extinguishers).
- Dioxin - actually a group of many chemicals - has carcinogenic and other toxic effects. Tobacco, whether chewed or smoked, is also carcinogenic.

Examples of biological poisons by source

::Unfinished task: Items below should be added as examples under the appropriate poison class above.

Non-radioactive inorganic poisons

- Arsenic compounds
- arsenic trioxide
- Fowler's solution
- inorganic compounds
- phosgene
- phosphine
- hydrogen sulfide
- Acids and bases, corrosives
- various light metal oxides, hydroxides, superoxides
- Bleach, some pool chemicals, other hypochlorates (acidic and oxydizing effect)
- hydrofluoric acid

Organic poisons

- formaldehyde

Naturally produced poisons and toxins

- Microorganisms
- ethanol
- botulin toxin
- Tetrodotoxin
- domoic acid (or Amnesic Shellfish Poison, ASP)
- Shellfish toxins (PSP, DSP, NSP, ASP )
- snake and spider venoms
- plant toxins (including many alkaloids)
- strychnine
- solanine
- atropine
- hyoscyamine
- aconite
- curare
- digitoxin
- digoxin
- poison hemlock
- hemlock water dropwort
- Phytohaemagglutinin (Red kidney bean poisoning)
- Grayanotoxin (Honey intoxication)
- fungal toxins
- amanita toxin, see Amanita phalloides
- muscarine
- aflatoxins
- Ciguatera poisoning
- Scombroid poisoning
- Ouabain
- Pyrrolizidine alkaloids

Famous poisonings

See also victims of poisoning

Confirmed poisonings

- Bhopal Disaster — An accidental release of poisonous gas from a pesticide plant in India that killed over 2,000 people and injured many more.
- Jonestown inhabitants — died from a poisoned drink in a mass suicide/murder: see Jonestown mass suicide
- Love Canal — Buried toxic waste was covered and used as a building site for housing and school in Niagara Falls, New York, resulting in claims of chronic poisoning and a massive environmental cleanup.
- Clare Boothe Luce — Fell ill but did not die; arsenic poisoning
- Georgi Markov — Assassinated in London with ricin
- Socrates — According to Plato, killed by drinking Hemlock (water hemlock, not hemlock the evergreen tree)
- Alan Turing — Apparently committed suicide by painting an apple with Cyanide and taking a bite.
- Viktor Yushchenko — poisoned with dioxin during the Ukrainan elections.

Suspected or rumoured poisonings

- Yasser Arafat — Arafat reputedly died from liver cirrhosis, which may be a consequence of chronic alcohol use or poisoning. Some Arafat supporters feel it is unlikely that Arafat habitually used alcohol (forbidden by Islam), and so suspect poisoning. However, it is also important to note that cirrhosis is not necessarily caused by alcohol use, or indeed any poison at all.
- Napoleon Bonaparte — some claim he was killed by someone on his staff with arsenic. Evidence is inconclusive.
- Charles Darwin — possibly died due to self-medication with Fowler's solution, one percent potassium arsenite
- Jamestown colonists — Standard historical accounts claim deaths by starvation, but the possibility of arsenic poisoning by rat poison (or of death by Bubonic plague) has also been reported (see [http://www.pbs.org/wnet/secrets2/case3_clues.html here])
- Joseph Stalin — Officially cerebral hemorrhage; but, according to Vyacheslav Molotov's memoirs, Lavrenty Beria claimed to have poisoned Stalin.

Poisons in crime fiction

This list is incomplete, given that poisoning is a frequent plot twist in crime fiction.

Novels

- Anthony Berkeley: The Poisoned Chocolates Case
- John Dickson Carr: The Burning Court
- Agatha Christie: Three Act Tragedy
- Agatha Christie: A Pocket Full of Rye
- Agatha Christie: Crooked House
- Agatha Christie: And Then There Were None
- Sir Arthur Conan Doyle: A Study in Scarlet
- Sir Arthur Conan Doyle: The Adventure of the Devil's Foot
- Freeman Wills Crofts: The 12.30 from Croydon
- Ann Granger: Say It With Poison
- Francis Iles: Before the Fact (filmed as Suspicion)
- Francis Iles: Malice Aforethought
- Raymond Postgate: Verdict of Twelve
- Dorothy Sayers: The Unpleasantness at the Bellona Club
- Dorothy Sayers: Strong Poison
- Rex Stout: Fer-de-Lance
- Rex Stout: The Red Box
- Rex Stout: Black Orchids
- Cornell Woolrich: Waltz into Darkness (filmed as Mississippi Mermaid and Original Sin)

Plays

- Joseph Kesselring: Arsenic and Old Lace
- Shakespeare: Hamlet
- Shakespeare: Romeo and Juliet

Films

- D.O.A.
- Arsenic and Old Lace

Poison in other literary works

This list is incomplete.

Novels

- Alexandre Dumas (père): The Count of Monte Cristo and The Three Musketeers
- Gustave Flaubert: Madame Bovary

External links

- [http://www.atsdr.cdc.gov/ Agency for Toxic Substances and Disease Registry] Category:Toxicology ja:毒 simple:Poison

Suicide

Suicide (from Latin sui caedere, to kill oneself) is the act of willfully ending one's own life; it is sometimes a noun for one who has committed or attempted the act. Suicide is viewed in highly varying ways among the cultures, religions, legal and social systems of the world. It is considered a sin or immoral act in many religions, and a crime in some jurisdictions. On the other hand, some cultures have viewed it as an honorable way to exit certain shameful or hopeless situations. Persons attempting or dying by suicide sometimes leave a suicide note. According to stricter definitions of suicide, to be considered suicide, the death must be a central component and intention of the act, not just a certain consequence; hence, suicide bombing is considered a kind of bombing rather than a kind of suicide, and martyrdom usually escapes religious or legal proscription. Generally, there are only legal consequences when there is death and proof of intent. However, not all follow this narrower definition. Certainly, a suicide bomber knows that death will be part of the outcome of his or her actions.

Medical views on suicide

Modern medical views on suicide consider suicide to be a mental health issue. Severe suicidal thoughts are considered a medical emergency. Mental health practitioners consistently advise suicidal people to seek help. This is especially true if the means (weapons, drugs, or other methods) are available, or if a detailed plan is in place. Suicidal patients in mental hospitals may be temporarily bound, placed in padded rooms, or incapacitated with drugs to limit access to means of suicide.

Suicide as the form of fight and protest

Heroic suicide, for the greater good of others, is often celebrated. For instance, Gandhi went on a hunger strike to prevent fighting between Hindus and Muslims, and although they stopped before he died, if they hadn't, he may have indeed killed himself. For this, he earned the respect of many. Monks in the Communist Vietnam of the 1960s drew Western praise with their protests based on self-immolation (burning themselves to death). Similar events were reported in the previously independent Eastern Europe during the Soviet occupation (see Jan Palach). Not everybody would count all these actions as suicides, as the personal death was clearly not the primary purpose. The opponents argue that these persons would probably achieve the comparable result by spending the rest of their life in the active fight.

Arguments for Pro-Choice and Pro-Euthanasia

There are arguments in favor of allowing an individual to choose between life and suicide. This view sees suicide as a valid option. This line rejects the widespread belief that suicide is always or usually irrational, saying instead that it is a genuine, albeit severe, solution to real problems – a line of last resort that can legitimately be taken when the alternative is considered worse. No being should be made to suffer unnecessarily, and suicide provides an escape from suffering in certain circumstances, such as incurable disease and old age. In the past, the Japanese were often ordered to commit seppuku, a form of ritual disembowelment suicide, by their superiors, and were expected to do so as a matter of honor. They may also have done it as a matter of free choice, also for the sake of honor, and it was considered better than being taken prisoner. A few rare groups say that people should kill themselves for the greater good. For example, the Church of Euthanasia says that people should kill themselves in order to reduce mankind's stress on the environment.

Epidemiology

It is probable that the incidence of suicide is widely under-reported due to both religious and social pressures, and possibly completely unreported in some areas. Nevertheless, from the known suicides, certain trends are apparent: for example, in the Western world, males die much more often than females by suicide, while females attempt suicide more often. Suicide rates in various nations have followed significant patterns over time, and it's often possible to anticipate suicides based on a person's social, economic, and psychological condition. The radical view would be that in the countries with the extremely high rate this may reflect the psychological problems of the whole society rather than the problems of that particular individual. However, there is insufficient data to adequately compare suicide rates among nations.

Combination of homicide and suicide

Since crime just prior to suicide is often perceived as being without consequences, it's not uncommon to combine homicide with suicide. Motivations range from wishing to be with one's family in an expected afterlife to avoiding punishment to killing others as part of a suicide pact.

Attempted suicide and parasuicide

Many suicidal people participate in suicidal activities which do not result in death. These activities fall under the designation attempted suicide or parasuicide. Generally, those with a history of such attempts are almost 23 times more likely to eventually end their own lives than those without. Sometimes, a person will make actions resembling suicide attempts while not being fully committed, or in a deliberate attempt to have others notice. This is called a suicidal gesture (also known as a "cry for help"). Prototypical methods might be a non-lethal method of self-harm that leaves obvious signs of the attempt, or simply a lethal action at a time when the person considers it likely that they will be rescued or prevented from fully carrying it out. On the other hand, a person who genuinely wishes to die may fail, due to lack of knowledge about what they are doing; unwillingness to try methods that may end in permanent damage if they fail or harm to others; or an unanticipated rescue, among other reasons. This is referred to as a suicidal attempt. Distinguishing between a suicidal attempt and a suicidal gesture may be difficult. Intent and motivation are not always fully discernable since so many people in a suicidal state are genuinely conflicted over whether they wish to end their lives. One approach, assuming that a sufficiently strong intent will ensure success, considers all near-suicides to be suicidal gestures. This however does not explain why so many people who fail at suicide end up with severe injuries, often permanent, which are most likely undesirable to those who are making a suicidal gesture. Another possibility is those wishing merely to make a suicidal gesture may end up accidentally killing themselves, perhaps by underestimating the lethality of the method chosen or by overestimating the possibility of external intervention by others. Suicide-like acts should generally be treated as seriously as possible since if there is an insuffic