Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «P»:
PRK (photorefractive keratectomy)
PRK (photorefractive keratectomy): A kind of
laser eye surgery designed to
change the shape of the cornea to eliminate (or reduce) the
need for glasses
and contact lenses. The laser is used to remove the outer
layer of the
and flatten the cornea. The flattening of the cornea is
PRKAR1A: Stands for Protein Kinase A Regulatory subunit 1-alpha. A multiple neoplasia syndrome called type I Carney complex is due to mutation of the PRKAR1A gene, which is on chromosome 17q23-q24. See also: Carney complex....
Pro: Proline. See also: Amino acid symbols....
Pro time: The pro time (or, more properly, the prothrombin time) is a test of the integrity of part of the clotting scheme. The prothrombin time is also commonly used as a method of monitoring the accuracy of blood thinning treatment (anticoagulation) with drugs such as Coumadin.
Probability: The likelihood that something will
happen. For example, a probability of less than .05 indicates that
the probability of something occurring by chance alone is less than 5
in 100, or 5 percent. This level of probability is usually taken as
the level of biologic significance, so a hi...
Proband: The family member through whom a family's
medical history comes to light. For example, a proband might be a
baby with Down syndrome. The proband may also be called the index
case, propositus (if male), or proposita (if female)....
Probe: (1) In surgery, a probe is a slender flexible rod
with a blunt end used to explore, for example, an opening to see where it goes. (2) In
molecular genetics, a probe is a labeled bit of DNA or RNA used to find its complementary
sequence or locate a particular clone like homing in on a needle i...
Probiotic: A microbe that protects its host and prevents disease. The best-known probiotic is Lactobacillus acidophilus, which is found in yogurt, acidophilus milk, and supplements. Probiotics counter the decimation of helpful intestinal bacteria by antibiotics. Probiotics given in combination with ...
Probiotics: live microorganisms (usually bacteria) that are
similar to beneficial microorganisms found in the human gut that are taken as
dietary supplements or found in foods. Most probiotics
are bacteria similar to
those naturally found in the intestine. Common examples...
PROC: Protein C ...
Procedure, Whipple: See: Whipple procedure....
Process: In anatomy, a process is a projection from a
structure. The process of
the mandible is the part of the lower jaw that projects forward. In a more general sense, a process is a series of actions or events that are part of a system or of a development, particularly one characterized by gradua...
Proclivity: An inclination or predisposition toward
something, especially a strong inherent inclination toward something
objectionable. For example, a patient might be said to have a
proclivity toward alcohol....
Procollagen: A precursor (forerunner) of collagen, the protein that adds strength and support to many body tissues....
Proctitis: Inflammation of the rectum. This may be due to a considerable number of causes, among them infectious agents and ulcerative colitis.
Infectious proctitis is often due to agents such as Chlamydia trachomatis, Neisseria gonorrheae (the bacteria that causes gonorrhea) and herpes simplex vi...