Category: Ca-Ca
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Cataract
A clouding or loss of transparency of the lens in the eye as a result of tissue breakdown and protein clumping. There are many causes of cataracts, including aging, cortisone medication, trauma, diabetes, and other diseases. Cataracts affect most people who live into an old age. Symptoms include double or blurred vision and sensitivity to light and glare. A physician can diagnose…
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Cataplexy
A debilitating condition in which a person suddenly feels weak and collapses at times of strong emotion such as during laughter, anger, fear, or surprise. In so collapsing, people with cataplexy may injure themselves. For example, laughter and other emotions may trigger a reflex that can bring many of the muscles of the body to the point of collapse.…
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Cataplasm
A poultice or plaster. A soft moist mass, often warm and medicated, that is spread over the skin to treat an inflamed, aching or painful area, to improve the circulation, etc. From the Greek kataplasma, poultice, from kataplasso, to spread over. See also: Mustard plaster; Poultice.
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Catalyst
A substance that speeds up a chemical reaction but is not consumed or altered in the process. Catalysts are of immense importance in chemistry and biology. All enzymes are catalysts that expedite the biochemical reactions necessary for life. The enzymes in saliva, for example, accelerate the conversion of starch to glucose, doing in minutes what would otherwise take…
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CAT scan
Computerized axial tomography scan. CAT scanning is a painless X-ray test in which a computer generates cross-section views of a patient’s anatomy. It can identify normal and abnormal structures, and it can be used to guide procedures. Contrast material is sometimes used in CAT scanning. A patient who is allergic to iodine or contrast materials and is scheduled to have a CAT scan should notify…
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Cast
1) A protective shell of fiberglass, plastic, or plaster, and bandage that is molded to protect broken or fractured limb(s) as it heals. 2) An abnormal mass of dead cells that forms in a body cavity. For example, cases of cells that form in the tubules of the kidneys are sometimes detected in urine samples.
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Cassette
A pre-existing structure into which an insert can be moved. In molecular biology, a gene conversion process in which the old gene is replaced with a copy of a silent gene and the new copy becomes active. As the process involves replacing one ready made construct with another in an active slot, it is termed a cassette mechanism.
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Cashew allergy
An allergic reaction to cashew nuts. Cashew allergy can be isolated, meaning that the individual is only allergic to cashews and not to other nuts, or the allergy may extend to other kinds of tree nuts such as walnuts and pistachios. Isolated cashew allergy can strike children or adults. No prior exposure to cashews is required for an allergic reaction to…
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Caseous
Cheeselike. In caseous lymphadenitis, the lymph nodes turn into a soft, dry, crumbly mass resembling cheese, usually due to tuberculosis or a related infection. From caseum, the Latin word for cheese.
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Cascade
A sequence of successive activation reactions involving enzymes (enzyme cascade) or hormones (hormone cascade) characterized by a series of amplifications of an initial stimulus. In blood coagulation, for example, each enzyme activates the next until the final product, the fibrin clot, is reached.