Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «R»:
Ribozyme: An RNA molecule that can catalyze its own chemical reactions....
Rice genome: The first commercially important plant to have its genome sequenced. This feat, completed early in 2001, is particularly important because rice is a staple food for a large portion of the population of the world. With the rice sequence, genes can be located to improve yields and make ri...
Rice rat: A rodent capable of carrying the types of hantavirus that cause HPS (hantavirus pulmonary syndrome) in the US. The rice rat measures 5 to 6 inches for the head and body, plus a very long 4 to 7 inch tail. Rice rats sport short, soft, grayish brown fur on top, and gray or tawny underbellies...
Richard L. Varco
Richard L. Varco: See: Varco, Richard L....
Ricin: A potent protein toxin made from the waste left over from processing castor beans. The castor plant, which is called Ricinus communis, is found throughout the world. Ricin is fairly easy to extract. Worldwide a million tons of castor beans are processed annually in the production of castor o...
Ricker syndrome: See: Myotonic dystrophy type 2....
A disease of infants and children that disturbs normal bone formation (ossification). Rickets is a failure to mineralize bone. This softens bone (producing osteomalacia) and permits marked bending and distortion of bones. Up through the first third of the 20th century, rickets was largely d...
Rickets, celiac: Rickets caused by failure of the
intestines to absorb calcium and fat from foods....
Rickets, hypophosphatemic: A familial form of rickets characterized by hypophosphatemia (low blood phosphate level), defective intestinal absorption of phosphate, and rickets unresponsive to vitamin D. The basic problem is decreased resorption of phosphate by the tubules in the kidney.
There are t...
Rickets, renal: Rickets-like bone malformations
caused by prolonged inflammation of the kidneys....
Rickets, vitamin D resistant
Rickets, vitamin D resistant: A rickets-like
condition caused by an inborn defect of metabolism, usually
in males. Vitamin D cannot be absorbed, and so does not
work to treat the illness....
Ricketts, Howard T.
Ricketts, Howard T.: American pathologist and pioneering infectious disease expert (1871-1910) who was the first to establish the identity of the infectious organism that causes Rocky Mountain spotted fever. He and others characterized the basic epidemiologic features of the disease, including the r...
Rickettsia: A member of a group of
microorganisms that (like viruses) require other living cells for
growth but (like bacteria) use oxygen, have metabolic enzymes and
cell walls, and are susceptible to antibiotics. Rickettsiae cause a
series of diseases named for the American pathologist Howard R...
Rickettsial diseases: The infectious diseases caused by
the rickettsiae fall into 4 groups:(1) typhus: epidemic typhus, Brill-Zinsser disease,
murine (endemic) typhus, and scrub typhus; (2) spotted fever-Rocky Mountain spotted
fever, Eastern tick-borne rickettsioses, and rickettsialpox; (3) Q fever...
Rickettsialpox: A mild infectious disease first
observed in New York City caused by Rickettsia akari, transmitted from its mouse host by
chigger or adult mite bites. There is fever, a dark spot that becomes a small ulcer at the
site of the bite, swollen glands (lymphadenopathy) in that region, and a...