metrorrhagia Uterine bleeding at irregular intervals, particularly between periods. Metrorrhagia can cause significant anemia. It may also be a sign of underlying disease, such as hormone disorder, uterine fibroids, or cancer of the uterus. See also menometrorrhagia; menorrhagia.
methotrexate An immune-suppressing drug (brand names: Rheumatrex, Trexall) that is used to treat rheumatoid arthritis, severe psoriasis, reactive arthritis, and severe asthma. In high doses it is also used as a part of cancer chemotherapy programs. Methotrexate is an effective but potentially dangerous medication. People taking methotrexate must have their lung, liver, and kidney function…
methimazole An antithyroid medication (brand name: Tapazol) that is prescribed to treat hyperthyroidism. Also known as thiamazole.
methicillin-resistant Staphylococcus aureus Staphylococcus aureus (a type of staph bacteria) resistant to the antibiotic methicillin. Abbreviated MRSA. MRSA first appeared among people in hospitals and other health facilities, especially among the elderly, the very sick, and those with an open wound, an IV catheter, or a urinary catheter. MRSA has since been found to cause…
methemoglobin A form of hemoglobin that is incapable of carrying oxygen, sometimes found in the blood after certain poisonings, such as with aniline, nitrates, and other compounds.
methadone A synthetic opiate. The most common medical use for methadone is as a legal substitute for heroin in treatment programs for drug addiction.
metatarsal One of the five cylindrical bones that extend from the heel to the toes.
metastasize The process cancer cells go through in spreading from one part of the body to another. See also metastasis.
metastasis 1 The spread of cancerous cells from one part of the body to another. The cells may be carried by the lymphatic system or in the blood. Cells that have metastasized are like those in the original (primary) tumor. For example, if the cancer begins in the stomach and spreads to the lung, the…
metastases, meningeal See meningitis, neoplastic.
metaphase chromosome A chromosome in the stage of its cell life in which it is most condensed and easiest to see separately. Because metaphase chromosomes are easier to study than others, they are often chosen for karyotyping and chromosome analysis.
metacarpal One of the five cylindrical bones that extend from the wrist to the fingers.