Medications

Mast cell tumor: A mastocytoma.Last Editorial Review: 5/26/2004 Mastocytoma: A form of mastocytosis characterized by a benign nodular skin tumor infiltrated by mast cells. Usually present at birth or in early childhood and resolves spontaneously. Al...

Mast cell - Medical

Mast cell: A connective tissue cell whose normal function is unknown but which is frequently injured in allergic reactions, releasing chemicals including histamine that are very irritating and cause itching, swelling, and fluid leakage from cells. Th...

Masseter - Medical

Masseter: The muscle that raises the lower jaw. Last Editorial Review: 4/27/2011 5:27:15 PM...

MASS syndrome - Medical

MASS syndrome: A heritable disorder of connective tissue characterized by involvement of the mitral valve, aorta, skeleton, and skin. Hence, the acronym MASS (Mitral valve, Aorta, Skeleton, Skin). The MASS syndrome is due to a mutation in FBN1, t...

Mass spectrometry - Medical

Mass spectrometry: An instrument used to identify chemicals in a substance by their mass and charge. Mass spectrometers are instruments that essentially weigh molecules. A mass spectrometer also can measure how much of a compound is present in a mixt...

Masochism - Medical

Masochism: Pleasure from one's own pain. Masochism is considered a sexual disorder, or paraphilia. Named after the 19th-century Austrian writer Leopold von Sacher-Masoch (masoch-ism). Last Editorial Review: 4/27/2011 5:27:15 PM...

Masklike face - Medical

Masklike face: An expressionless face with little or no sense of animation, a face more like a mask than a real face. A masklike face is seen in a number of disorders including Parkinson's disease and myotonic dystrophy. Also called masklike fac...

Mask, oxygen - Medical

Mask, oxygen: A mask that covers the mouth and nose, and is hooked up to an oxygen tank. It delivers oxygen directly to the patient. Oxygen can also be delivered directly through a nasal catheter, a tube that divides into two smaller tubes that g...

Mask of pregnancy - Medical

Mask of pregnancy: Muddy-brown pigmentation on the cheeks or elsewhere on the face that develops in about half of all women during pregnancy. Some women also develop it outside pregnancy, as do some women on hormone therapy. The pigmentation is wors...

MASA syndrome - Medical

MASA syndrome: MASA stands for mental retardation, aphasia, shuffling gait, and adducted thumbs. Features of the syndrome include: neurologically: mental retardation and aphasia (lack of speech); limbs: adducted (clasped) thumbs, abse...

Marx, Gertie F. - Medical

Marx, Gertie F.: Distinguished German-born American physician known as the "mother of obstetric anesthesia." She almost singlehandedly developed obstetric anesthesiology as a specialty. She advanced the use of epidural injections to ease women's pain...

Marx - Medical

Marx: See: Marx, Gertie F. Last Editorial Review: 1/29/2004 Marx, Gertie F.: Distinguished German-born American physician known as the "mother of obstetric anesthesia." She almost singlehandedly developed obstetric anesthesiology as a specialty. Sh...

Martorell syndrome - Medical

Martorell syndrome: Named after Fernando Martorell Otzet, Spanish cardiologist (1906-1984). In 1944 Martorell provided an excellent description of a syndrome also known today as Takayasu disease. See: Takayasu disease. Last Editorial Review: 8/30/...

Martinus W. Beijerinck - Medical

Martinus W. Beijerinck: See: Beijerinck, Martinus W.Last Editorial Review: 9/12/2004 Beijerinck, Martinus W.: (1851-1931) Dutch microbiologist who was the first person to use the term "virus" for the invisible disease-causing material that he show...

Martin Rodbell - Medical

Martin Rodbell: See: Rodbell, Martin. Last Editorial Review: 1/16/2004 Rodbell, Martin: (1925-1998) American biochemist and molecular endocrinologist who shared the Nobel Prize in 1994 in Physiology or Medicine for his discovery of G-proteins and th...

Marshall-Smith syndrome - Medical

Marshall-Smith syndrome: A disorder characterized by advanced bone age at birth, broad forehead, prominent eyes, and small chin. There is difficulty feeding, failure to thrive, retarded psychomotor development, and predisposition to respiratory infec...

Marshall W. Nirenberg - Medical

Marshall W. Nirenberg: See: Nirenberg, Marshall W.Last Editorial Review: 1/16/2004 Nirenberg , Marshall W.: (b. 1927) American biochemist who shared the 1968 Nobel Prize in Physiology or Medicine for his work in deciphering the genetic code. Marsha...

Nasal prosthesis - Medical

Nasal prosthesis: An artificial device to replace part or all of a missing nose. Last Editorial Review: 10/4/2003...

Marsh fever - Medical

Marsh fever: See malaria.Last Editorial Review: 4/27/2011 5:27:15 PM Medical Author: Charles Patrick Davis, MD, PhD Charles Patrick Davi...

Nasal polyps - Medical

Nasal polyps: Benign growths that originate in the mucous membranes lining the nasal passages or paranasal sinuses. Polyps are believed to arise in the nasal mucosa as a result of chronic inflammation. Up to 4% of adults have nasal polyps; they can a...

Marrow - Medical

Marrow: The bone marrow.Last Editorial Review: 4/27/2011 5:27:15 PM Bone marrow: The soft blood-forming tissue that fills the cavities of bones and contains fat and immature and mature blood cells, including white blood cells, red blood cells, and...

Marriage, cousin - Medical

Marriage, cousin: A form of consanguinity. Everyone carries recessive alleles, genes that are generally innocuous in the heterozygous state but that in the company of another gene of the same type are capable of causing disease. We are all genetic...

Nasal polyp - Medical

Nasal polyp: Benign growths that originate in the mucous membranes lining the nasal passages or paranasal sinuses. Polyps are believed to arise in the nasal mucosa as a result of chronic inflammation. Up to 4% of adults have nasal polyps; they can al...

Maroteaux-Lamy syndrome - Medical

Maroteaux-Lamy syndrome: A form of mucopolysaccharidosis with the clinical onset before age 3 that is characterized by an inability to metabolize dermatan sulfate. This leads to abnormal accumulation of dermatan sulfate, resulting in mild to severe c...

Marmoreal - Medical

Marmoreal: Resembling marble. For example, the bone in osteoporosis appears marmoreal. From the Latin noun "marmor" meaning "marble."Last Editorial Review: 12/10/2002 Medical Author: William C. Shiel Jr., M...

Nasal passage - Medical

Nasal passage: The walls of the nasal passages are coated with respiratory mucous membranes which contain innumerable tiny hair-like cells that act to move waves of mucus toward the throat. Dust, bacteria, and other particles inhaled from the air are...

Marker, tumor - Medical

Marker, tumor: Tumor markers are substances that can be detected in higher-than-normal amounts in the blood, urine, or body tissues of some patients with certain types of cancer. A tumor marker may be made by a tumor itself or by the body in response...

Nasal mucus - Medical

Nasal mucus: A slippery fluid produced by the membranes lining the nose. Excessive nasal mucus is the basis of a runny nose. Mucus is the Latin word for "a semifluid, slimy discharge from the nose." Last Editorial Review: 1/18/2004...

Nasal flu vaccine - Medical

Nasal flu vaccine: A live attenuated (weakened) influenza virus vaccine that is administered as a nasal spray. The brand name for this vaccine is FluMist. The nasal flu vaccine is recommended only for healthy people between 5 and 49 years of age....

Marker, blood - Medical

Marker, blood: A sign of a disease or condition that can be isolated from a blood sample. For example, the monoclonal antibody D8/17 is a diagnostic sign of Pediatric Autoimmune Disorders associated with Strep.Last Editorial Review: 4/27/2011 5...