Psoralens Health Dictionary

Psoralens: From 1 Different Sources


See PHOTOCHEMOTHERAPY; PHOTODERMATOSES.
Health Source: Medical Dictionary
Author: Health Dictionary

Celery

Nutritional Profile Energy value (calories per serving): Low Protein: Moderate Fat: Low Saturated fat: Low Cholesterol: None Carbohydrates: High Fiber: Moderate Sodium: High Major vitamin contribution: Folate Major mineral contribution: Potassium, phosphorus

About the Nutrients in This Food Celery has moderate amounts of dietary fiber and small amounts of the B vitamin folate. One-half cup diced raw celery has one gram dietary fiber and 17 mcg folate (4 percent of the R DA).

The Most Nutritious Way to Serve This Food Fresh, filled with cheese to add protein.

Diets That May Restrict or Exclude This Food Low-fiber diet Low-sodium diet

Buying This Food Look for: Crisp, medium-size pale green celery with fresh leaves. Darker stalks have more vitamin A but are likely to be stringy. Avoid: Wilted or yellowed stalks. Wilted stalks have lost moisture and are low in vitamins A and C. Yellowed stalks are no longer fresh; their chlorophyll pigments have faded enough to let the yellow carotenes show through. Avoid bruised or rotten celery. Celery cells contain chemicals called furocoumarins (pso- ralens) that may turn carcinogenic when the cell membranes are damaged and the furocou- marins are exposed to light. Bruised or rotting celery may contain up to a hundred times the psoralens in fresh celery.

Storing This Food Handle celery carefully to avoid damaging the stalks and releasing furocoumarins. Refrigerate celery in plastic bags or in the vegetable crisper to keep them moist and crisp. They will stay fresh for about a week.

Preparing This Food R inse celery under cold running water to remove all sand and dirt. Cut off the leaves, blanch them, dry them thoroughly, and rub them through a sieve or food mill. The dry powder can be used to season salt or frozen for later use in soups or stews.

What Happens When You Cook This Food When you cook celery the green flesh will soften as the pectin inside its cells dissolves in water, but the virtually indestructible cellulose and lignin “strings” on the ribs will stay stiff. If you don’t like the strings, pull them off before you cook the celery. Cooking also changes the color of celery. Chlorophyll, the pigment that makes green vegetables green, is very sensitive to acids. When you heat celery, the chlorophyll in its stalks reacts chemically with acids in the celery or in the cooking water to form pheophytin, which is brown. The pheophytin will turn the celery olive-drab or, if the stalks have a lot of yellow carotene, bronze. You can prevent this natural chemical reaction and keep the celery green by cooking it so quickly that there is no time for the chlorophyll to react with the acids, or by cooking it in lots of water (which will dilute the acids), or by cooking it with the lid off the pot so that the volatile acids can float off into the air.

Adverse Effects Associated with This Food Contact dermatitis. Celery contains limonene, an essential oil known to cause contact der- matitis in sensitive individuals. (Limonene is also found in dill, caraway seeds, and the peel of lemon and limes.) Photosensitivity. The furocoumarins (psoralens) released by damaged or moldy celery are photosensitizers as well as potential mutagens and carcinogens. Constant contact with these chemicals can make skin very sensitive to light, a problem most common among food work- ers who handle large amounts of celery without wearing gloves. Nitrate/nitrite poisoning. Like beets, eggplant, lettuce, radish, spinach, and collard and turnip greens, celery contains nitrates that convert naturally into nitrites in your stomach and then react with the amino acids in proteins to form nitrosamines. Although some nitro- samines are known or suspected carcinogens, this natural chemical conversion presents no known problems for a healthy adult. However, when these nitrate-rich vegetables are cooked and left to stand at room temperature, bacterial enzyme action (and perhaps some enzymes in the plants) convert the nitrates to nitrites at a much faster rate than normal. These higher-nitrite foods may be hazardous for infants; several cases of “spinach poison- ing” have been reported among children who ate cooked spinach that had been left standing at room temperature.... celery

Photodermatoses

Diseases of the SKIN for which sunlight is partially or wholly responsible. In su?cient dosage, short-wave ultraviolet light (UVB – see ULTRAVIOLET RAYS (UVR)) always causes ERYTHEMA. Higher doses progressively cause OEDEMA and blistering; this is acute sunburn. Graduated exposure to UVB causes pigmentation (tanning). Prolonged chronic exposure to sunlight eventually accelerates ageing of the exposed skin with LENTIGO formation and loss of COLLAGEN and elastic tissue. After decades of such exposure, epidermal DYSPLASIA and CANCER may supervene.

Drugs given orally or topically may induce phototoxic reactions of various types. Thus, TETRACYCLINES exaggerate sunburn reactions. and the diuretic FRUSEMIDE may cause blistering reactions. Psoralens induce erythema and pigmentation. AMIODARONE also induces pigmentation. (See also PHOTOCHEMOTHERAPY.)

Phytophotodermatitis is a streaky, blistering photodermatosis typically seen on the limbs of children playing in grassy meadows in summer. The phototoxic reaction is caused by psoralens in weeds.

Berlocque dermatitis is a pattern of streaky pigmentation usually seen on women’s necks, caused by a reaction to psoralens in perfumes.

Certain rare metabolic diseases may lead to photosensitisation. They include the PORPHYRIAS and PELLAGRA. Other skin diseases such as lupus erythematosus (see under LUPUS) and ROSACEA may be aggravated by light exposure. Sometimes, in the absence of any of these factors, some people spontaneously develop a sensitivity to light causing various patterns of DERMATITIS or URTICARIA. The most common pattern is ‘polymorphic light eruption’ which typically appears within a day or two of arrival at a sunny holiday destination and persists until departure. Continuously exposed areas, such as the hands and face, may be ‘hardened’ and unaffected.

Treatment Appropriate clothing and headgear, sunscreen creams and lotions are the main preventative measures.... photodermatoses

Psoralen Drugs

Drugs containing chemicals called psoralens, which occur in some plants and are present in some perfumes.

When absorbed into the skin, psoralens react with ultraviolet light to cause skin darkening or inflammation.

Psoralen drugs may be used in conjunction with ultraviolet light (a combination called PUVA) to treat psoriasis and vitiligo.

Overexposure to ultraviolet light during treatment, or to too high a dose of a psoralen drug, may cause redness and blistering of the skin.

Psoralens in perfumes may cause photosensitivity.... psoralen drugs




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