Actinic: Referring to the ultraviolet (UV) rays from sunlight and UV lamps. Sunburn is an actinic burn. An actinic keratosis is a skin lesion that is the consequence of chronic sun exposure.
- Actinic keratosis
Rough, scaly patches of skin that are considered precancerous and are due to sun exposure. Prevention is to cut sun exposure and wear sunscreen. Treatments include performing cryosurgery (freezing with liquid nitrogen), cutting the keratoses away, burning them, putting 5-fluorouracil on them, and using photodynamic therapy (injecting into the bloodstream a chemical that collects in […]
Actinomycetes: A group of gram-positive bacteria (order Actinomycetales) that produce various bioactive agents including antibiotics, enzymes, and vitamins. Streptomyces belong to this bacterial order.
- Activated charcoal
Activated charcoal: Charcoal that has been heated to increase its ability to absorb molecules. Activated charcoal is used to help relieve intestinal gas. It is also used to filter and purify liquids, to absorb poisons (as in gas mask filters), and in emergency situations to neutralize swallowed poisons.
- Active euthanasia
Active euthanasia: The active acceleration of a “good” death by use of drugs etc, whether by oneself or with the aid of a doctor. The word “euthanasia” comes from the Greek — “eu” meaning “goodly or well” + “thanatos” meaning “death.” So, euthanasia is literally the “good death.” In 18th-century England, that was what euthanasia […]
- Active immunity
Active immunity: Immunity produced by the body in response to stimulation by a disease-causing organism or other agent.