Search Results

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 a group of drugs of diverse chemical structure and physiological effects that are used for the relief of pain. Analgesics are drugs, including opiates, synthetic opioids, and salicylates, that are used primarily for pain relief (see…

A chemical substance, produced by microorganisms, plants, marine organisms, and synthetically, that has the capacity in dilute solutions to inhibit the growth of bacteria or destroy bacteria. Antibiotics are important antibacterial agents. Most are…

The capability that a bacterium acquires to counteract an inhibitory chemical molecule or compound that was formerly effective in killing it or preventing its growth. Antibiotic resistance in bacteria (Fig. 1) is a hot topic in the media and in…

Chemical compounds biosynthetically or synthetically produced that destroy or usefully suppress the growth or metabolism of a variety of microscopic or submicroscopic forms of life. On the basis of their primary activity, antimicrobial agents (see…

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…

The most common type of arrhythmia (any disorder of the heart rate or rhythm). Atrial fibrillation, often abbreviated AFib or AF, is a heart condition that can lead to potentially serious complications. It is associated with decreased quality of…

A genus of pathogenic gram-negative bacteria that are coccobacilli and obligate aerobes, and fail to ferment carbohydrates. Bordetella bacteria are respiratory pathogens. Bordetella pertussis, B. parapertussis, and B. bronchiseptica share greater…

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 more than…

A genus comprising yeasts that cause a variety of human diseases referred to as candidiasis. All Candida species are single-celled yeasts (fungal organisms) that are ovoid in shape and 3–5 μm in size, and they multiply by a process called budding.…

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 genus of bacteria, including a number of important human pathogens, comprising large anaerobic spore-forming rods that usually stain Gram-positive. Most species of the genus Clostridium are anaerobes, but a few will grow minimally in air at…

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 ability of an organism to resist the action of an inhibitory molecule or compound. Drug resistance is the decreased reactivity of living organisms to the injurious actions of certain drugs and chemicals. Examples of drug resistance include…

A subdiscipline in the field of microbiology concerned with the study of bacteria, fungi, and viruses that grow in or are transmitted by foods. Food microbiology is a broad field that can include not only microbiology, but also sanitation,…

An organism that has had its genetic material manipulated or altered in a laboratory setting through the use of genetic or genomic engineering techniques. Genetically modified organisms (GMOs) are microorganisms, plants, or animals that have been…

Pathologies of the heart and its blood vessels. The heart is the muscular pumping organ of the cardiovascular system of vertebrates (Fig. 1). However, a diseased or defective heart can have serious consequences. Almost all cardiovascular or heart…

A type of human cancer cell maintained in tissue culture since 1951, originally excised from the cervical carcinoma of a patient named Henrietta Lacks. The first immortal human cells to grow successfully outside the human body were labeled HeLa…

The study of bacteria that cause human disease. The field of medical bacteriology encompasses the detection and identification of bacterial pathogens (Fig. 1), the determination of the sensitivity and mechanisms of resistance of bacteria to…

A type of skin cancer caused by the uncontrolled proliferation of epidermal melanocytes (cells containing dark pigments). Melanoma (see illustration) is well known for its rapid progression, metastasis, and poor prognosis. Statistics from the United…

The collective term for the microorganisms or microbes that inhabit an environment, creating an ecological community or ecosystem; also the collective genetic material of these microorganisms or microbes. The term microbiome has a dual meaning.…

A disease or infection acquired in a hospital or other health-care facility. Nosocomial diseases are pathological disorders that occur in patients during the course of a hospital stay. They also can occur in other health-care facilities, such as a…

An experience of discomfort, primarily associated with tissue damage. Pain involves somesthetic sensations that are generally unpleasant and often cause suffering or distress. Pain (see illustration) is more complex than other sensory systems, such…

An inherited disorder of red blood cells characterized by lifelong anemia and recurrent painful episodes. Sickle cell disease, also termed sickle cell anemia, is a chronic, hereditary hemolytic and thrombotic disease in which hypoxia (oxygen…

Disorders or disturbances of the reversible state during which an individual's voluntary functions are suspended, but the involuntary functions (such as circulation and respiration) are uninterrupted. Sleep is a state of rest in which consciousness…

A branch of medicine concerned with the effects of exercise and sports on the human body, including treatment of injuries. Sports medicine investigates the functioning and conditioning of the human body during physical activity. It can be divided…

A potentially fatal infectious disease caused by protozoan parasites of the genus Trypanosoma. Trypanosomiasis, or sleeping sickness, is the term used to describe a number of diseases affecting vertebrate animals. The causal agents of…

Two babies born to a mother at one birth. There are two types of twins—monozygotic and dizygotic. Members of a twin pair are called co-twins (Fig. 1). Controversy surrounding the definition of a twin arose with the advent of reproductive…

An abnormal metabolic condition in which the pancreas produces little or no insulin and characterized by excessive levels of sugar glucose in the blood and tissues of the body. Type 1 diabetes (T1D; formerly termed insulin-dependent or juvenile…

A metabolic disorder characterized by the presence of excess glucose in the blood and tissues of the body, occurring as a result of resistance to insulin action coupled with an inadequate compensatory insulin secretory response. Type 2 diabetes…

A group of closely related polypyrrole compounds containing trivalent cobalt. Vitamin B12 has a chemical formula of C63H88CoN14O14P (see illustration). It is formed by the polymerization of pyrrole (an organic compound containing a doubly…