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Toxics
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). Sometimes the word is more or less synonymous with poisoning in everyday usage. A central concept of toxicology is that the effects of a toxicant are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypass animal testing, while maintaining the concept of toxicity endpoints. Etymology In Ancient Greek medical literature, the adjective ''τοξικόν'' (meanin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cytotoxicity
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of drugs, e.g alcohol, and some venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa'') are toxic to cells. Cell physiology Treating cells with the cytotoxic compound can result in a variety of prognoses. The cells may undergo necrosis, in which they lose membrane integrity and die rapidly as a result of cell lysis. The cells can stop actively growing and dividing (a decrease in cell viability), or the cells can activate a genetic program of controlled cell death (apoptosis). Cells undergoing necrosis typically exhibit rapid swelling, lose membrane integrity, shut down metabolism, and release their contents into the environment. Cells that undergo rapid necrosis in vitro do not have sufficient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Toxicant
A toxicant is any toxic substance, whether artificial or naturally occurring. By contrast, a toxin is a poison produced naturally by an organism (e.g. plant, animal, insect, bacterium). The different types of toxicants can be found in the air, soil, water, or food. Occurrence Toxicants can be found in the air, soil, water, or food. Humans can be exposed to environmental toxicants. Fish can contain environmental toxicants. Tobacco smoke contains toxicants. E-cigarette aerosol also contains toxicants. The emissions of a heat-not-burn tobacco product contains toxicants. Most heavy metals are toxicants. Diesel exhaust contains toxicants. Pesticides, benzene, and asbestos-like fibers such as carbon nanotubes are toxicants. Possible developmental toxicants include phthalates, phenols, sunscreens, pesticides, halogenated flame retardants, perfluoroalkyl coatings, nanoparticles, e-cigarettes, and dietary polyphenols. Related terms By contrast, a toxin is a poison produced natu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Skull And Crossbones (poison)
A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under or behind the skull. The design originated in the Late Middle Ages as a symbol of death and especially as a ''memento mori'' on tombstones. Actual skulls and bones were long used to mark the entrances to Skull and crossbones (Spanish cemetery), Spanish cemeteries (campo santo). In modern contexts, it is generally used as a hazard symbol, usually in regard to poisonous substances, such as deadly chemicals. It is also associated with piracy and software piracy, due to its historical use in some Jolly Roger flags. Military use The skull and bones are often used in military insignia, such as the coats of arms of regiments. Since the mid-18th century, skull and crossbones insignia has been officially used in European armies as symbols of superiority. One of the first regiments was the Frederick the Great's Hussars in 1741, also known as the "". From this tradition, the skull ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Paradigm
In science and philosophy, a paradigm ( ) is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field. The word ''paradigm'' is Ancient Greek, Greek in origin, meaning "pattern". Etymology ''Paradigm'' comes from Greek παράδειγμα (''paradeigma''); "pattern, example, sample"; from the verb παραδείκνυμι (''paradeiknumi''); "exhibit, represent, expose"; and that from παρά (''para''); "beside, beyond"; and δείκνυμι (''deiknumi''); "to show, to point out". In classical (Greek-based) rhetoric, a paradeigma aims to provide an audience with an illustration of a similar occurrence. This illustration is not meant to take the audience to a conclusion; however, it is used to help guide them to get there. One way of how a ''paradeigma'' is meant to guide an audience would be exemplified by the role of a personal accountant. It is not the job of a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Toxin
A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from '' toxic''. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. They vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. Less strict understandings embrace naturally occurring inorganic toxins, such as arsenic. Other understandings embrace synthetic analogs of naturally occurring organic poisons as toxins, and may or may not embrace naturally oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cholera Toxin
Cholera toxin (also known as choleragen, CTX, CTx and CT) is a potent enterotoxin produced by the bacterium Vibrio cholerae which causes severe watery diarrhea and dehydration that define cholera infections. The toxin is a member of the heat-labile enterotoxin family, and exists as an AB5 multimeric toxin with one enzymatically active A subunit and five receptor-binding B subunits that facilitate host cell entry. History The cholera toxin is the causative pathogenic agent of the ancient disease cholera, thought to have emerged in the Ganges Delta. For centuries the toxin remained confined to this region, but 19th-century globalisation spread it worldwide through the course of seven subsequent pandemics. When cholera arrived in London in 1832, its transmission was poorly understood, with many blaming miasma. Physician, John Snow (1813-1858) was an advocate of water contamination as the cause of its spread - famously ending an outbreak by removing a public water pump handle in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Immune System
The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic worms, and also objects such as wood splinters, distinguishing them from the organism's own healthy biological tissue, tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use humoral immunity, molecules and cell-mediated immunity, cells to perform their functions. Nearly all organisms have some kind of immune system. Bacteria have a rudimentary immune system in the form of enzymes that protect against bacteriophage, viral infections. Other basic immune mechanisms evolved in ancien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Infection
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an Disease#Terminology, illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently pathogenic bacteria, bacteria and viruses. Hosts can fight infections using their immune systems. Mammalian hosts react to infections with an Innate immune system, innate response, often involving inflammation, followed by an Adaptive immune system, adaptive response. Treatment for infections depends on the type of pathogen involved. Common medications include: * Antibiotics for bacterial infections. * Antivirals for viral infections. * Antifungals for fungal infections. * Antiprotozoals for protozoan infections. * Antihelminthics for infections caused by parasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Worm
Worms are many different distantly related bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes. Worms vary in size from microscopic to over in length for marine polychaete worms (bristle worms); for the African giant earthworm, ''Microchaetus rappi''; and for the marine nemertean worm (bootlace worm), ''Lineus longissimus''. Various types of worm occupy a small variety of parasitism, parasitic niches, living inside the bodies of other animals. Free-living worm species do not live on land but instead live in marine or freshwater environments or underground by burrowing. In biology, "worm" refers to an obsolete taxon, ''Vermes'', used by Carl Linnaeus, Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, now seen to be paraphyletic. The name stems from the Old English word ''wikt:wyrm, wyrm''. Most animals called "worms" are invertebrates, but the term is also use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of List of virus species, virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Threshold Dose
Threshold dose is the minimum dose of drug that triggers minimal detectable biological effect in an animal. At extremely low doses, biological responses are absent for some of the drugs. The increase in dose above threshold dose induces an increase in the percentage of biological responses. Several benchmarks have been established to describe the effects of a particular dose of drug in a particular species, such as NOEL(no-observed-effect-level), NOAEL(no-observed-adverse-effect-level) and LOAEL(lowest-observed-adverse-effect-level). They are established by reviewing the available studies and animal studies. The application of threshold dose in risk assessment safeguards the participants in human clinical trials and evaluates the risks of chronic exposure to certain substances. However, the nature of animal studies also limits the applicability of experimental results in the human population and its significance in evaluating potential risk of certain substances. In toxicology, ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of disease, germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or Transmission (medicine), transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
