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A common medicine used to relieve mild to moderate pain and reduce fever. Acetaminophen (N-acetyl-p-aminophenol), or paracetamol, is a white crystalline compound with the molecular formula C8H9NO2 (Fig. 1). It is a member of the aniline family of…

A disease of the nervous system characterized by a progressive dementia that leads to profound impairment in cognition and behavior. Dementia occurs in a number of brain diseases where the impairment in cognitive abilities represents a decline from…

Any of the cells within a tumor that possess the capacity to self-renew and cause the heterogeneous lineages of cancerous cells that comprise the tumor. Cancer stem cells (CSCs) typically represent a small percentage of all cells in a tumor (rarely…

The administration of chemical substances for the treatment of disease, especially cancer, or for the prevention of aberrant growth of cells or tissues (neoplasms). In general, chemotherapy is the use of chemicals to treat any disease, but the term…

A genome-engineering technique that allows precise targeting of specific stretches of genetic code and editing of DNA at designated locations. The CRISPR/Cas9 system has been used as a general tool to engineer the genomes of many different…

The interaction of the behavior and ecology of hosts with the biology of pathogens as relating to the impact of diseases on populations. Although human diseases have been studied from an ecological perspective for centuries, diseases in plant and…

The use of pollen and spore evidence in legal cases. In its broader application, the field of forensic palynology also includes legal information derived from the analysis of a broad range of microscopic organisms that can be found in both fresh and…

A plant that has altered genetic material (DNA) through recombinant DNA (rDNA) manipulation. Genetic engineering of plants allows for very specific genetic changes to be made to a plant's deoxyribonucleic acid (DNA), as opposed to the random…

A commercially grown plant that has altered genetic material through artificial recombinant manipulation. Genetic modification is the latest scientific tool for developing improved crop varieties. Such genetically modified (GM) crops can help to…

A biological organism whose genetic material has been manipulated artificially through genetic or genomic editing techniques. In contrast to the long history of artificial selection (domestication), in which humans selectively breed organisms to…

Pathologies or aberrations in structure or function of blood cells or the blood-clotting mechanism. Hematologic disorders affect the blood and blood-forming organs. Although many diseases and abnormal conditions may be reflected by the blood and its…

A procedure used to remove toxins, fluids, and other substances from the body when the kidneys are unable to handle this removal naturally. In the medical field, medical dialysis is simply referred to as dialysis. The removal of toxins, fluids, and…

An autoimmune disease resulting from an abnormality in neuromuscular transmission, characterized by a fluctuating degree of muscle weakness. Myasthenia gravis is a chronic autoimmune neuromuscular disorder (see illustration) characterized by varying…

A progressive degenerative disorder of the nervous system belonging to a group of conditions called motor system disorders. Parkinson's disease—more specifically known as idiopathic Parkinson's disease to distinguish it from the four Parkinson-plus…

In medicine and health sciences, a value expected for an individual whose state of health is known and well described, and the interval of values broadly expected for a population, respectively. Results of clinical laboratory tests and other…

A rare genetic disorder in which there is a deficiency of hexosaminidase A (a lysosomal enzyme that hydrolyzes GM2 gangliosides). Tay-Sachs disease is a severe and progressive neurodegenerative disease. Because of the deficiency of hexosaminidase A…

The process of forming a thrombus, which is a solid mass or plug in the living heart or vessels composed of the constituents of the blood. Thrombosis usually occurs in a diseased blood vessel, as a result of arteriosclerosis. The consequences of…

An aqueous solution of organic and inorganic substances—mostly waste products of metabolism—that collects in the kidneys and is removed from the body primarily through the urinary bladder and urinary tract. Urine is a liquid waste produced by the…

Diseases that are transmitted from animals to humans. Zoonoses (the singular form is zoonosis) are also termed zoonotic diseases. They are infectious diseases passed from animals (Fig. 1) to humans. Zoonotic agents are found among all major…

A plant, Musa textilis, of the banana family that is valuable for its hard fiber (also known as Manila hemp). Abaca (Musa textilis) is a flowering plant native to the Philippines and Borneo. Taxonomically, it is assigned to the order Zingiberales.…

A major plant hormone that plays an important role in plant growth and development. Abscisic acid (ABA), with a chemical formula of C15H20O4 (Fig. 1), is one of the most significant hormones found in plants. It is responsible for regulating various…

A viral disease of humans caused by the human immunodeficiency virus (HIV), which attacks and compromises the body's immune system. Individuals infected with the human immunodeficiency virus (HIV) proceed through a spectrum of stages that ultimately…

Habituation to a specific practice, such as drinking alcoholic beverages or using drugs (for example, heroin, cocaine, or amphetamines), and disorders characterized by the chronic use of a drug, alcohol, or similar substance. Addiction and addictive…

Malfunctions of the paired adrenal glands. The paired adrenal glands are complex endocrine organs in proximity to the kidneys (see illustration), and disorders of the adrenal glands can have serious consequences. Under specific circumstances,…

Mechanized systems of food and fiber production used in agriculture. The mechanized systems comprising agricultural machinery are utilized in numerous aspects of agriculture, including the initial tillage of the soil (Fig. 1), planting, cultural…

The repeated and/or excessive use of alcohol (ethanol) that continues despite negative physical, psychiatric, or social consequences. Alcoholism is characterized by consuming alcohol more often, in larger amounts, or over longer periods than…

An informal assemblage of predominantly aquatic eukaryotes that carry out oxygen-evolving photosynthesis, but lack specialized water-conducting and food-conducting tissues. Algae (Fig. 1) are eukaryotic organisms (having an organized nucleus).…

A small, tropical, evergreen tree (Pimenta dioica) and its dried, unripe fruit (berry). Allspice (Pimenta dioica; alternatively, P. officinalis) [see illustration] is a member of the myrtle family (Myrtaceae). Allspice, which is also known as…

Any of the organic compounds possessing one or more basic amino groups and one or more acidic carboxyl groups. Of the more than 80 amino acids that have been found in living organisms, approximately 20 serve as the building blocks for proteins.…

A class of steroid hormones produced in the testes and adrenal cortex that act to regulate masculine secondary sexual characteristics. The major naturally occurring androgens, such as testosterone, are C-19 steroids (that is, they each contain 19…

A synthetic manufactured drug derived from the male sex hormone testosterone. Androgenic-anabolic steroids, often termed simply as anabolic steroids, are artificially produced testosterone variants. They can provide a number of medical benefits when…

Loss of sensation with or without loss of consciousness. Anesthesia is used to prevent pain during surgery and other medical procedures. There are several ways of producing anesthesia, with the choice dependent on the type of surgery and the medical…

The use of live nonhuman animals for scientific research and experimentation. Animal testing has been a cornerstone of biomedical research, having contributed greatly to the understanding of human biology, to the unraveling of the complex underlying…

A type of drug that inhibits the combination of histamine with histamine receptors. Antihistamine drugs are termed either H-1 or H-2 receptor antagonists, depending on which type of histamine receptor is involved. H-1 receptor antagonists are used…

Any vegetable that is prevalent in Asian cuisines, but less well known in Western diets. Asian vegetables (Fig. 1), also referred to as Asian greens or oriental vegetables, are very important in Asian countries, but are not as popular in North…

Any treatment or procedure that includes the in-vitro handling of oocytes (immature ova or egg cells) and sperm or embryos for the purpose of establishing a pregnancy. Assisted reproductive technology (ART) is undertaken as a treatment of…

Any of a class of plant growth substances (phytohormones or plant hormones) that have an essential role in coordination of many growth and developmental processes during the life cycle of plants, especially the ability to increase the rate of shoot…

A class of nonflagellate unicellular algae, commonly called diatoms, with boxlike silicified walls. Members of the algal class Bacillariophyceae are commonly termed diatoms (Fig. 1). Diatoms range in maximum dimension from 4 μm (0.00004 in.) to more…

A highly contagious intestinal disease, also known as shigellosis, caused by rod-shaped bacteria of the genus Shigella. Bacillary dysentery, which also is referred to as shigellosis, is a significant intestinal infection. Rod-shaped bacteria of the…

Any of a group of drugs used for the suppression of anxiety, the induction of sleep, and the control of seizures. Barbiturates are sedative-hypnotic drugs, derived from barbituric acid, that act as central nervous system depressants (see…

Any of several leguminous plants, or their seeds, long utilized as food by humans or livestock. There are more than 40,000 varieties of beans, with only a small number of these being mass-produced for human or animal consumption. In particular,…

The drug as well as the plant known as deadly nightshade (Atropa belladonna). The belladonna plant (Atropa belladonna; see illustration) belongs to the nightshade family, Solanaceae, in the order Solanales. The plant is a coarse and poisonous…

A biological product used to induce immunity to various infectious diseases or noxious substances of biological origin. Biological products, or simply biologicals, are usually limited to immune serums, antitoxins, vaccines (see illustration), and…

Fungi that exhibit the natural phenomenon of bioluminescence (the ability of an organism to emit visible light). Bioluminescence is the emission of photons of visible light by living organisms via the chemical reaction of molecular oxygen (O2) with…

Identifying exposure sources, routes, frequency, duration, and magnitude using biomarker data combined with other approaches, such as computational models and available environmental measurement data. The goal of environmental health science is to…

The application of chemical engineering principles to the solution of medical problems due to physiological impairment. Knowledge of organic chemistry is required of all chemical engineers, and many study biochemistry and molecular biology. This…

An integrated device consisting of a biological recognition element and a transducer capable of detecting the biological reaction and converting it into a signal that can be processed. Ideally, the sensor should be self-contained, so that it is not…

A garden for the culture of plants collected chiefly for scientific, educational, and esthetic purposes. A botanical garden (see illustration) is an establishment in which various plants, including trees, are collected, cultivated, and grown for…

The branch of biological science that embraces the study of plants and plant life. Botany is the scientific study of plants (see illustration), encompassing investigations of plant anatomy, physiology, genetics, phylogeny, ecology, pathology, and…

Malignant and benign lesions of the human mammary glands. Breast cancer and other breast disorders are potentially serious medical conditions. Benign breast disorders are often symptomatic and bothersome, but do not have malignant potential.…