a substance that makes another substance active or reactive, induces a chemical reaction, or combines with an enzyme to increase its catalytic activity.
tissue plasminogen activator
(TPA, t-PA) (t-plasminogen activator
) a serine endopeptidase synthesized by endothelial cells, the major physiologic activator of plasminogen
; when bound to fibrin
clots it catalyzes the conversion of plasminogen to plasmin
by hydrolysis of a specific arginine-valine bond. It can be produced by recombinant technology for use in thrombolytic therapy
. It acts directly on blood clots and therefore presents a small risk of systemic bleeding; occasionally allergic reactions may occur.
(urinary plasminogen activator
) a serine endopeptidase that acts as a plasminogen activator by catalyzing the preferential cleavage of plasminogen at the same arginine-valine bond where t-plasminogen activator
cleaves. It is produced in the kidney and excreted in the urine and is used in thrombolytic therapy
(when used as a pharmaceutical, it is usually called urokinase
). Unlike t-plasminogen activator or prourokinase, it does not require fibrin
for activity. Called also urokinase
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
1. A substance that renders another substance (for example, a catalyst) active, or that accelerates a process or reaction.
2. The fragment produced by chemical cleavage of a proactivator, that induces the enzymic activity of another substance.
3. An apparatus for making substances radioactive (for example, a neutron generator or a cyclotron).
4. A removable type of myofunctional orthodontic appliance that acts as a passive transmitter of force, produced by the function of the activated muscles, to the teeth and alveolar process that are in contact with it.
5. A protein that binds to a DNA sequence before RNA polymerase transcription, sometimes referred to as coactivator.
Farlex Partner Medical Dictionary © Farlex 2012
Activator A protein that binds DNA at transcription control or enhancer sites—e.g., for an allosteric enzyme—and upregulates—i.e., positively regulates—gene transcription. Activators either increase binding of RNA polymerase to the promoter site or stimulate RNA polymerase to begin transcription.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
1. A substance that renders another substance active, or one that accelerates a process or reaction.
2. The fragment, produced by chemical cleavage of a proactivator, which induces the enzymatic activity of another substance.
3. An apparatus for making substances radioactive.
4. A removable type of myofunctional orthodontic appliance that acts as a passive transmitter of force, which is produced by the function of the activated muscles, to the teeth and alveolar process that are in contact with it.
5. A protein that binds to a DNA sequence before DNA polymerase transcription.
6. Manually assisted thrust instrument that activates mechanoreceptors; used by many chiropractors.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
activator any drug that increases the activity level of the person being treated.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
1. A substance that renders another substance active, or accelerates a process or reaction.
A removable type of myofunctional orthodontic appliance that acts as a passive transmitter of force, produced by the function of the activated muscles, to the teeth and alveolar process that are in contact with it.
See also: accelerator
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about activator
Q. Are there any nice activities for adults with autism? I've been helping a very nice man of 45 of years old and I'm looking for some new things I can do with him in our time together. any ideas?
A. Autistic people react wonderfully with animals. for instance- i saw a group of severe Autistic teenagers going to swim with dolphins. the effect was amazing! taking him to the zoo, or even to the park to feed ducks, pet dogs, whatever.. could have a great effect on him.
hope i helped!
tell me how it went.
Q. what is a passive smoking? and is it dangerous as an active?
A. Passive smoking is the exposure to cigarettes smoke emitted from cigarettes smoke by other person. It's dangerous and may increase the risk to several diseases similar to active smoking (one's exposure to smoke emitted from the cigarettes he or she is smoking) although the risk is of lower magnitude. Example for passive smoking is children of smokers etc.
You may read more here:http://www.nlm.nih.gov/medlineplus/secondhandsmoke.html
Q. i swim a lot ! what are the advantages of swimming over other sport activities? on what part of the body does it work the most ?
A. its a good workout but your not really going to burn as much calories as a regular work out.More discussions about activator
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