Thursday, March 31, 2011

Foods and anaphylaxis

An extreme reaction of the immune system in response to exposure to foreign substances. Insect bites, drugs, injected serum, and certain foods can create anaphylaxis. This abnormal response or immediate hypersensitivity is usually very rapid in susceptible individuals who may have been sensitized by previous exposure, and may produce shock (“anaphylactic shock”). The massive release of histamines and other inflammatory agents leads to spasming of smooth muscles, especially those of the air passageways, and to widespread swelling due to the increased water leaking out of capillaries. Symptoms range from asthma to fever, itching, hives, and flushed skin in mild cases, to chest constriction, irregular pulse, painful, labored breathing, and convulsions in severe cases. Anaphylaxis can be life-threatening and may require emergency room care.

What is anaerobic

Cellular processes that do not require oxygen. Energy can be produced in cells without oxygen. Anaerobic GLYCOLYSIS refers to an energy yielding process by which ATP, the energy currency of the cell, is produced from GLUCOSE without the participation of oxygen. As an example, skeletal muscle produces LACTIC ACID and ATP from glucose when oxygen supplied to muscle is inadequate to meet energy needs during strenuous physical exertion.
Accumulated lactic acid is then converted back to glucose during the recovery period following EXERCISE when the oxygen supply is again adequate.
Anaerobic processes are important for certain bacteria as well. Anaerobic bacteria in the intestine grow without oxygen and block the growth of potential disease-producing microorganisms. Anaerobic fermentation of SUGAR by yeast yields alcohol-containing products such as WINE and BEER.

What is anabolism (biosynthesis)?

Processes involved in synthesizing the molecules needed for cellular growth and maintenance. Thus the formation of PROTEIN, DNA, RNA, LIPID, CARBOHYDRATE, FAT, and GLYCOGEN are anabolic processes. Anabolism consumes chemical energy in the form of ATP and NADPH (a reducing agent), which are supplied by CATABOLISM, the energy-yielding oxidative processes involved in degradation. Optimal function and health rely upon a balance of anabolic and catabolic processes (homeostasis). These two branches of metabolism are controlled by the ENDOCRINE SYSTEM, which in turn responds to external influences such as diet. Anabolic processes require small building blocks supplied by breaking down STARCH, PROTEIN, and FAT in foods to build larger molecules. GLYCEROL and FATTY ACIDS are the subunits of fat; AMINO ACIDS yield proteins; and glucose yields glycogen. Fat and carbohydrate degradation provides an energized form of ACETIC ACID (acetyl CoA) to synthesize fatty acids and cholesterol. Other specialized products are also assembled from several different types of smaller precursors. For example, heme, the iron-containing pigment of the oxygen transport protein HEMOGLOBIN, is synthesized from an amino acid (GLYCINE) and SUCCINIC ACID, a common intermediate in energy-producing pathways.
Growth and an anabolic state, seen as an increase in body mass and muscle mass, occur during childhood, adolescence, pregnancy, and strenuous physical activity, such as body building. The weight gained in these situations represents increased protein, bone, or fat, not fluids. Increased fat stores and accumulated body fat represent stored surplus energy in adults and can result from too little exercise, the over-consumption of FOOD, heredity, or a combination of the above factors.