Deoxyribonucleic acid Health Dictionary

Specifically, the abnormal buildup of acids in the body, classically caused by diabetes or kidney disease. Broadly, the potential caused by increased protein intake or metabolism, coupled with inadequate intake (or loss) of alkali.... acidosis

A colourless, pungent, fuming liquid. Secreted by the parietal cells in the lining of the stomach, it aids in the digestion of the food.... hydrochloric acid

The final end product of certain native or dietary proteins, especially the nucleoproteins found in the nucleus of cells. Unlike the much smaller nitrogenous waste product urea, which is mostly recycled to form many amino acids, uric acid is an unrecyclable metabolite. It is a bent nail that won’t restraighten, and it must be excreted: nucleoprotein to purine to uric acid to the outside in the urine or the sweat. (See GOUT, PURINES.)... uric acid

Chemical compounds that are the basic building-blocks of all proteins. Each molecule consists of nitrogenous amino and acidic carboxyl groups of atoms joined to a group of carbon atoms. Polypeptides are formed by amino-acid molecules linking via peptide bonds. Many polypeptides link up in various con?gurations to form protein molecules. In humans, proteins are made up from 20 di?erent amino acids: nine of these are labelled ‘essential’ (or, as is now preferred, ‘indispensable’) amino acids because the body cannot manufacture them and is dependent on the diet for their provision. (See also INDISPENSABLE AMINO ACIDS.)... amino acids

Ascorbic acid, or vitamin C (see APPENDIX 5: VITAMINS), is a simple sugar found in living tissues – its highest concentrations being in the adrenal cortex (see ADRENAL GLANDS) and the eye. Stress and CORTICOTROPIN lead to a loss of ascorbic acid from the adrenal cortex. Fresh fruit and vegetables, particularly blackcurrants, citrus fruits, berries and green vegetables, are the richest dietary sources; it may also be synthetically prepared. Ascorbic acid is easily eliminated from the diet by traditional methods of cooking, being very soluble in water and easily destroyed by heat, alkalis, traces of copper or by an oxidase released by damage to plant tissues. De?ciency may lead to SCURVY, traditionally associated with sailors, among elderly people living alone or in poor communities living at subsistence level. It has been claimed that large doses (1–2 g daily) will prevent the common cold, but few large controlled trials have been carried out and it is inadvisable for people to dose themselves with large quantities of ascorbic acid, which may result in the formation of oxalate stones in the urinary tract. (See also VITAMIN.)... ascorbic acid

A valuable antistaphylococcal antibiotic used both orally and topically. It is particularly useful in osteomyelitis (see BONE, DISORDERS OF).... fusidic acid

One of the constituents of the vitamin B complex, folic acid derives its name from the fact that it is found in many green leaves, including spinach and grass. It has also been obtained from liver, kidney and yeasts. It has proved to be of value in the treatment of macrocytic anaemias (see ANAEMIA), particularly those associated with SPRUE and nutritional de?ciencies.

In order to prevent NEURAL TUBE defects and cleft lip or palate (see CLEFT PALATE), all women planning to become pregnant should be advised to have a diet rich in folic acid in the months before conception until 13 weeks’ gestation, or to take folic acid tablets.

Recent research has suggested that adequate levels of folic acid can prevent the build-up of homocysteine, a compound in the blood closely associated with heart attacks and strokes. It has been suggested that the o?cial recommendation of 200 micrograms a day in the diet should be doubled. (See APPENDIX 5: VITAMINS.)... folic acid

A colourless, syrupy, sour liquid, which is produced by the action of a bacterium upon lactose, the sugar found in milk. The growth of this organism and consequent formation of lactic acid cause the souring of milk, and the same change takes place to a limited extent when food is long retained in the stomach.

Lactic acid (CH3.CHOH.COOH) is produced in the body during muscular activity, the lactic acid being derived from the breakdown of GLYCOGEN. Muscle fatigue is associated with an accumulation of lactic acid in the muscle. Recovery follows when enough oxygen gets to the muscle, part of the lactic acid being oxidised and most of it then being built up once more into glycogen.... lactic acid

One of the NON-STEROIDAL ANTIINFLAMMATORY DRUGS (NSAIDS) that is an analgesic (see ANALGESICS) for mild to moderate pain in RHEUMATOID ARTHRITIS, OSTEOARTHRITIS and other musculoskeletal disorders. Also used for DYSMENNORRHOEA and MENORRHAGIA. It must be used with care as it has several side-effects, in particular diarrhoea and occasional haemolytic ANAEMIA. It must not be used in patients with INFLAMMATORY BOWEL DISEASE (IBD).... mefenamic acid

An antibiotic drug, active against gram-negative (see GRAM’S STAIN) micro-organisms, used to treat and prevent infections of the URINARY TRACT.... nalidixic acid

Nicotinic acid is a member of the vitamin B complex. It is essential for human nutrition, the normal daily requirement for an adult being about 15–20 mg. A de?ciency of nicotinic acid is one of the factors in the etiology of PELLAGRA, and either nicotine acid or NICOTINAMIDE is used in the treatment of this condition. Nicotinic acid also reduces the concentration of blood lipids (see HYPERLIPIDAEMIA).... nicotinic acid

Group of chemicals found in cells and which carry biochemical codes for heredity and day-to-dayfunctioning of cells.... nucleic acid

This is an irritant poison that is used domestically for cleaning purposes. It is also found in many plants including rhubarb and sorrel. Oxalic acid, when swallowed, produces burning of the mouth and throat, vomiting of blood, breathlessness and circulatory collapse. Calcium salts, lime water or milk should be given by mouth. An injection of calcium gluconate is an antidote.... oxalic acid

This plays an important part in the transfer of acetyl groups in the body’s METABOLISM and is one of the essential constituents of the diet. The daily requirement is probably around 10 milligrams. It is widely distributed in food stu?s, both animal and vegetable; yeast, liver and egg-yolk are particularly rich sources. (See APPENDIX

5: VITAMINS.)... pantothenic acid

A crystalline substance sparingly soluble in water that is used externally in ointments and pastes. It has antifungal properties and helps to loosen and remove scales. In high concentrations it is useful in treatment of verrucae (WARTS) and corns (see CORNS AND BUNIONS).... salicylic acid

A drug used in the control of bleeding. It inhibits the activation of PLASMINOGEN and FIBRINOLYSIS, and may be useful when bleeding cannot be stopped – for instance, dental extraction in HAEMOPHILIA. The drug is also useful in MENORRHAGIA.... tranexamic acid

A preparation used in the treatment of cholesterol gall-stones when laparoscopic CHOLECYSTECTOMY and endoscopic biliary procedures cannot be used (see GALL-BLADDER, DISEASES OF).... ursodeoxycholic acid

An organic acid produced by the LIVER when it is rapidly oxidising fatty acids – a metabolic process which occurs, for example, during starvation. The acid produced is then converted to ACETONE, which is excreted.... acetoacetic acid

In our context, a substance having a pH below that of neutral water (7.0) when in solution. Most metabolic waste products are acidic. Sour. See pH... acid

The balance between the acid and alkaline elements present in the blood and body ?uids.

The normal hydrogen ion concentration of the PLASMA is a constant pH 7·4, and the lungs and kidneys have a crucial function in maintaining this ?gure. Changes in pH value will cause ACIDOSIS or ALKALOSIS.... acid base balance

Carbolic acid, or phenol, was the precursor of all ANTISEPTICS. It paralyses and then destroys most forms of life, particularly organisms such as bacteria. It has been superseded by less penetrative and harmful antiseptics.... carbolic acid

One of the bile acids (see BILE), used in the treatment of cholesterol gall-stones for patients with mild symptoms when other modern techniques are unsuitable. (See GALL-BLADDER, DISEASES OF.)... chenodeoxycholic acid

This is responsible for the sharp taste associated with citrus fruits, such as lemons and limes, and other fruits such as currants and raspberries. Although chemically di?erent from, it is similar in action and appearance to tartaric acid, obtained from grapes and other fruits, and similar to malic acid, found in apples and pears.... citric acid

Three acids – arachidonic, linolenic and tinoleic – which are essential for life, but which the body cannot produce. They are found in natural vegetable and ?sh oils and their functions are varied. EFAs have a vital function in fat metabolism and transfer and they are also precursors of PROSTAGLANDINS.... essential fatty acids

See GABA.... gamma aminobutyric acid

An unsaturated fatty acid occurring widely in the glycerides of plants. It is an essential nutrient for mammals, including humans.... linoleic acid

The most common of naturally occurring fatty acids, being present in most fats and oils in the form of triglyceride. It is used in the preparation of OINTMENTS, but not eye ointments.... oleic acid

A yellow crystalline solid substance which is used as a ?xative for tissues being prepared for examination under a microscope; it is also used as a dye.... picric acid

See RNA.... ribonucleic acid

A bisphosphonate drug used in the treatment of osteoporosis and Paget’s disease of bone. The most common side effect is inflammation of the oesophagus, which causes heartburn or difficulty in swallowing. Other side effects can include headache and abdominal pain.... alendronic acid

One of the fatty acids in the body that are essential for growth.... arachidonic acid

A topical drug used to treat mild to moderate acne.... azelaic acid

A condition in which the kidneys are unable to excrete normal amounts of acid made by the body.

The blood is more acidic than normal, and the urine less acidic.

Causes include kidney damage due to disease, drugs, or a genetic disorder; but in many cases the cause is unknown.

The acidosis may result in osteomalacia, kidney stones (see calculus, urinary tract), nephrocalcinosis, and hypokalaemia (an abnormally low level of potassium in the blood).... renal tubular acidosis

See ASPIRIN.... acetylsalicyclic acid

Excretion of an acid URINE.... aciduria

A drug used to treat hereditary angio-oedema (see under URTICARIA) – a serious anaphylactic (see ANAPHYLAXIS) reaction of the skin and respiratory tract resulting from a de?ciency in the body’s immunological defence mechanisms (see IMMUNITY).... aminocaproic acid

Chromic acid is used in several industries, particularly in chromium plating. Unless precautions are taken it may lead to dermatitis of the hands, arms, chest and face. It may also cause deep ulcers, especially of the nasal septum and knuckles.... chromic acid

See INDISPENSABLE AMINO ACIDS.... essential amino acids

A potent diuretic, with a rapid onset, and a short duration (4–6 hours), of action. (See THIAZIDES; DIURETICS.)... ethacrynic acid

This is the new, preferred term for essential amino acids – amino acids which are essential for the body’s normal growth and development, but which the body is unable to produce. Nine essential amino acids exist – HISTIDINE, ISOLEUCINE, LEUCINE, LYSINE, METHIONINE, PHENYLALANINE, THREONINE, TRYPTOPHAN, and VALINE – and they are present in foods rich in protein: dairy products, eggs, meat, and liver.... indispensable amino acids

A preparation based on the thyroid (see THYROID GLAND) hormone triiodothyronine, which is prescribed to replace the lack of natural thyroid hormone (hypothyroidism). The drug is also used to treat goitre and cancer of the

thyroid gland. (See THYROID GLAND, DISEASES OF.)... liothyronine acid

Lysergic acid diethylamide belongs to the ergot group of ALKALOIDS. It has various effects on the brain, notably analgesic and hallucinogenic, thought to be due to its antagonism of 5hydroxytryptamine (5-HT). In small doses it induces psychic states, in which the individual may become aware of repressed memories. For this reason it may help in the treatment of certain anxiety states, if used under skilled supervision. LSD rapidly induces TOLERANCE, however, and psychological DEPENDENCE may occur, although not physical dependence. Serious side-effects include psychotic reactions, with an increased risk of suicide.... lysergic acid diethylamide (lsd)

Also known as mandelamine, a non-toxic keto-acid used in the treatment of infections of the urinary tract, especially those due to the Escherichia coli and the Streptococcus faecalis or Enterococcus. It is administered in doses of 3 grams several times daily. As it is only e?ective in an acid urine, ammonium chloride must be taken at the same time.... mandelic acid

One of the early antituberculous (see TUBERCULOSIS) antibiotics. It tended to cause DYSPEPSIA and has been replaced by newer antituberculous drugs with fewer side-effects. The ?rst-line drugs for tuberculosis are now rifampicin, isoniazid, and ethambutol.... para-amino salicylic acid

See CYANIDE POISONING.... prussic acid poisoning

... retinoic acid

A healthy bloodstream depends upon maintenance of an acid-alkaline balance. Blood is always slightly alkaline. Only slight variations on either side are compatible with life. When this delicate balance is disturbed by faulty elimination of acid wastes, carbon dioxide, etc., a condition appears known as acidosis, a known precursor of chronic disease. A change of diet is indicated.

To help restore the acid-alkaline balance, any one of the following teas may assist: Iceland Moss, Bladderwrack (fucus), Kelp, Irish Moss, Slippery Elm, Calamus, Meadowsweet, or Dandelion (which may be taken as Dandelion coffee). ... acid-alkaline balance

Foods that produce acid when metabolised. Ash from these foods contains sulphur, phosphoric acid and chlorine, all essential for efficient metabolism. Breads, cereals, cheese, chicken, chocolate, cocoa, coffee, cranberries, eggs, fish, flour, fowl, grain products, lentils, meats (lean), nuts, oats, oatmeal, oysters, pasta, peanuts, peanut butter, pearl barley, plums, prunes, rhubarb, rabbit, rice (white), sugar, sweet corn, tea, veal, wholemeal bread, wheatgerm. ... acid foods

Heartburn, with acid eructations and a sensation of distress in the stomach, chiefly associated with peptic ulcer (duodenal) or gastritis.

Symptoms: local tenderness and stomach gas. The terms hyperacidity and hyperchlorhydria refer to excessive production of hydrochloric acid in the stomach.

Alternatives. For preparation and dosage see remedy entry.

Teas: Agrimony, Balm, Black Horehound, Caraway, Catnep, Celery seeds, Centuary, Chamomile, Dandelion root coffee, Fennel, Irish Moss, Liquorice root, Meadowsweet, Parsley, Quassia, Red Sage. Tablets/capsules. Dandelion, Papaya, Goldenseal. Dosage as on bottle.

Powders: equal parts, Slippery Elm, White Poplar, Meadowsweet. Mix. 500mg (two 00 capsules or one- third teaspoon) thrice daily and when necessary.

Tinctures. Formula: Dandelion 1; Meadowsweet 1; Nettles 1; Goldenseal quarter. Dose: 1-2 teaspoons in water thrice daily before meals.

Practitioner prescription. Dec Jam Sarsae Co conc (BPC 1949) 1 fl oz (30ml); Liquid Extract Filipendula 1 fl oz (30ml); Liquid Extract Taraxacum off. Half a fl oz (15ml); Ess Menth Pip 0.05ml. Aqua to 8oz (240ml). Sig: one dessertspoon (8ml) in warm water before meals. (Barker).

Diet: lacto-vegetarian. Garlic. Celery. Dried raw oats. Regular raw food days. Low fat. Powdered kelp in place of salt. Paw paw fruit. Regulate bowels.

Note: In view of the finding of gastric carcinoid tumours in rodents subjected to long-term anti-secretory agents, caution needs to be exercised over the long-term use of antacids that powerfully suppress the gastric juices. ... acidity

A polyunsaturated fatty acid; an essential ingredient in the body’s production of prostaglandins. Present naturally in mother’s milk. The body produces GLA from linoleic acid present in food as an essential fatty acid (EFA). Vital to growth, cell structure and cardiac health. Sources: Evening Primrose oil; Sunflower seed oil, Borage and Blackcurrant. Preparations from the fermentation of rotten carrots. Helps lower blood pressure and prevent cholesterol build-up in the blood. ... gamma linolenic acid (gla)

The colourless, pungent, organic acid that gives vinegar its sour taste.

In medicine, acetic acid is an ingredient of antiseptic gels that are used for certain vaginal infections.... acetic acid

A combination of mechanisms that ensures that the body’s fluids are neither too acid nor too alkaline (alkalis are also called bases).

The body has three mechanisms for maintaining normal acid–base balance: buffers, breathing, and the activities of the kidneys. Buffers are substances in the blood that neutralize acid or alkaline wastes. Rapid breathing results in the blood becoming less acidic; slow breathing has the opposite effect. The kidneys regulate the amounts of acid or alkaline wastes in the urine.

Disturbances of the body’s acid–base balance result in either acidosis (excessive blood acidity) or alkalosis (excessive blood alkalinity).... acid–base balance

Regurgitation of acidic fluid from the stomach into the oesophagus due to inefficiency of the muscular valve at the lower end of the oesophagus. Also known as gastro-oesophageal reflux disease (GORD), acid reflux may inflame the oesophagus, resulting in heartburn due to oesophagitis. It may occur in pregnancy and often affects overweight people.... acid reflux

Acid rain air pollution is responsible for increased hospital admissions with respiratory illness when it hangs in a haze over a polluted area. The main components of acid rain are sulphates, salts of sulphur, known to cause breathing difficulties.

Alternatives. Teas: Alfalfa, Angelica leaves, Boneset, Catnep, Chamomile, Coltsfoot, Comfrey leaves, Dandelion leaves, Hyssop, Lemon Balm, Lime flowers, Milk Thistle, Mullein, White Horehound, Red Clover flowers, Sage, Violet leaves, Umeboshi tea.

Tablets/capsules. Chamomile, Echinacea, Iceland Moss, Irish Moss, Liquorice, Lobelia.

Powders. Formula. Equal parts: Echinacea, Barberry bark, Elecampane root. Dose: 500mg (two 00 capsules or one-third teaspoon) thrice daily.

Formula. Tinctures. Echinacea 2; Sarsaparilla 1; Fringe Tree half; Liquorice quarter. Mix. 1-2 teaspoons thrice daily. ... acid rain sickness

A friendly bacteria found in the digestive system which combats the activities of invading micro-organisms associated with food poisoning and other infections. The natural balance of intestinal flora can be disturbed by diets high in animal fat, dairy produce, sugar, stress and alcohol. Lactobacillus Acidophilus assists production of B vitamins, regulates cholesterol levels, enhances the immune system and helps absorption of food. Perhaps the most popular bacteria-friendly food is yoghurt.

L.A. is available in tablets and capsules. As a vaginal douche the powder can be used for thrush. It is necessary to follow the use of antibiotics of orthodox pharmacy. Of value for Candida albicans, allergies, depression and some forms of menstrual disorders. ... acidophilus

A group of unsaturated fatty acids essential for growth and body function. EFA activity requires three polyunsaturated fatty acids (linolenic, linoleic and arachidonic). The most essential are linoleic and arachidonic which are closely involved in metabolism, transport of fats, and maintenance of cell membranes. While linolenic and arachidonic acids can be synthesised in the body, linoleic cannot.

EFA deficiency may be caused by alcohol, particularly Omega-6. Deficiencies may be responsible for a wide range of symptoms from foul-smelling perspiration to psoriasis, pre-menstrual tension and colic. EFAs are precursors of prostaglandin formation.

EFAs are present in oily fish and reduce the adhesion of platelets and the risk of heart disease. They reduce blood cholesterol and increase HDLs.

Common sources: cold pressed seeds, pulses, nuts and nut oils. Evening Primrose oil (15-20 drops daily). The best known source is Cod Liver oil (1-8 teaspoons daily); (children 1 teaspoon daily to strengthen immune system against infection); bottled oil preferred before capsules. To increase palatability pour oil into honey jar half filled with orange or other fruit juice, shake well and drink from the jar.

Margarines, salad dressings, cooking and other refined vegetable oils inhibit complete absorption of EFAs and should be avoided. EFAs require the presence of adequate supply of Vitamins A, B, C, D, E and minerals Calcium, Iron, Magnesium and Selenium. ... essential fatty acids (efa)

Organic acids, containing carbon, hydrogen, and oxygen, that are constituents of fats and oils. There are more than 40 fatty acids, which are found in nature and which are distinguished by their constituent number of carbon and hydrogen atoms.

Certain fatty acids cannot be synthesized by the body and must be provided by the diet. These are linoleic, linolenic, and arachidonic acids, sometimes collectively termed essential fatty acids. Strictly speaking, only linoleic acid is essential, since the body can make the other 2 from linoleic acid obtained from food. (See also nutrition.)... fatty acids

An essential fatty acid found in evening primrose oil and starflower oil (borage oil).

Gamolenic acid may be prescribed for breast tenderness, premenstrual syndrome, and eczema.

Very large doses may cause abdominal pain and loose stools.... gamolenic acid

The active ingredient of many sunscreen preparations. Its abbreviation is.... para-aminobenzoic acid

see aspirin.... acetylsalicylic acid

n. abnormally high blood acidity. This condition may result from an increase in the concentration of acidic substances and/or a decrease in the level of alkaline substances in the blood. See also acidosis. Compare alkalaemia.... acidaemia

a technique for creating a mechanical bond between resin-based materials and the enamel of teeth; it is used to retain and seal the margins of composite fillings, to retain brackets of fixed orthodontic appliances, and to retain resin-based *fissure sealants and adhesive bridges. Phosphoric acid is used to create a porous surface into which a bonding agent can flow.... acid-etch technique

Substances found in all living matter that have a fundamental role in the propagation of life. Nucleic acids provide the inherited coded instructions (or “blueprint”) for an organism’s development.

There are 2 types of nucleic acid: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). In all plant and animal cells, including human cells, DNA permanently holds the coded instructions, which are translated and implemented by RNA. DNA is the main constituent of chromosomes, which are carried in the nucleus (central unit) of the cell.

DNA and RNA are similar in structure, both comprising long, chain-like molecules. However, DNA usually consists of 2 intertwined chains, whereas RNA is generally single-stranded.

The basic structure of DNA has been likened to a rope ladder, the chains forming the 2 sides, with interlinking structures in between forming the rungs.

The ladder is twisted into a spiral shape called a double helix.

Each DNA chain has a “backbone” consisting of a string of sugar and phosphate chemical groups. Attached to each sugar is a chemical called a base, which can be any of 4 types (adenine, thymine, guanine, and cytosine) and forms half a rung of the DNA ladder. The 4 bases can occur in any sequence along the chain. The sequence, which may be many millions of individual bases long, provides the code for the activities of the cell (see genetic code).

RNA is like a single strand of DNA; the main difference is that the base thymine is replaced by another base, uracil.When a cell undergoes mitotic (see mitosis) division, identical copies of its DNA must go to each of the 2 daughter cells. The 2 DNA chains separate, and 2 more chains are formed, side by side with the original chains. Because only certain base pairings are possible, the new double chains are identical to the original DNA molecule. Each of a person’s cells carries the same DNA replica that was present in the fertilized ovum, so the DNA message passes from one generation of cells to the next.... nucleic acids

adj. 1. describing bacteria that have been stained and continue to hold the stain after treatment with an acidic solution. For example, tuberculosis bacteria are acid-fast when stained with a *carbol fuchsin preparation. 2. describing a stain that is not removed from a specimen by washing with an acidic solution.... acid-fast

(acidophilic) adj. 1. (in histology) describing tissues, cells, or parts of cells that stain with acid dyes (such as eosin). See also adenoma. 2. (in bacteriology) describing bacteria that grow well in acid media.... acidophil

an organic compound containing an amino group (–NH2) and a carboxyl group (–COOH). Amino acids are fundamental constituents of all *proteins. They are classified as *essential amino acids, i.e. those that cannot be synthesized by the body, and nonessential amino acids, which can be synthesized by the body. Certain amino acids present in the body are not found in proteins; these include *citrulline, *ornithine, *taurine, and *gamma-aminobutyric acid.... amino acid

(aspartate) see amino acid.... aspartic acid

an antiseptic, active against fungi and bacteria, used as a preservative in foods and pharmaceutical preparations and, combined with salicylic acid, in the form of an ointment (Whitfield’s ointment) for the treatment of ringworm.... benzoic acid

the organic acids in bile; mostly occurring as bile salts (sodium glycocholate and sodium taurocholate). They are cholic acid, deoxycholic acid, glycocholic acid, and taurocholic acid.

cebile-acid sequestrant a drug that binds to bile acids, forming a complex that is excreted in the faeces. Bile acids are formed in the liver from *cholesterol and the effect of loss of bile acids is a reduction in total body cholesterol and a decrease in *low-density lipoprotein serum levels. These drugs, which include *colestyramine and *colestipol, are used to treat patients with abnormally high blood cholesterol levels who are liable to develop coronary heart disease.... bile acids

(cholalic acid) see bile acids.... cholic acid

see Krebs cycle.... citric acid cycle

a drug that interferes with the *penicillinases that inactivate *beta-lactam antibiotics, such as *amoxicillin or *ticarcillin. Combined with the antibiotic, clavulanic acid can overcome drug resistance.... clavulanic acid

see bile acids.... deoxycholic acid

an *amino acid that is essential for normal growth and development but cannot be synthesized by the body. Essential amino acids are obtained from protein-rich foods in the diet, such as meat, fish, eggs, and dairy products. Adults require eight essential amino acids: leucine, isoleucine, valine, phenylalanine, threonine, methionine, tryptophan, and lysine. Children require an additional nine, as their body’s requirement is greater than can be synthesised by it: tyrosine, glycine, cysteine, arginine, proline, histidine, glutamine, serine, and asparagine.... essential amino acid

an organic acid with a long straight hydrocarbon chain and an even number of carbon atoms. Fatty acids are the fundamental constituents of many important lipids, including *triglycerides. Some fatty acids can be synthesized by the body; others, the *essential fatty acids, must be obtained from the diet. Examples of fatty acids are palmitic acid, oleic acid, and stearic acid. See also fat; saturated fatty acid; unsaturated fatty acid.... fatty acid

a derivative of folic acid involved in purine synthesis. It is used to reverse the biological effects of methotrexate and other *dihydrofolate reductase inhibitors and so to prevent excessive toxicity. This action is termed folinic acid rescue. Folinic acid has a potentiating effect with *fluorouracil, with which it is often used.... folinic acid

a sugar acid derived from glucose. Glucuronic acid is an important constituent of *chondroitin sulphate (found in cartilage) and *hyaluronic acid (found in synovial fluid).... glucuronic acid

(glutamate) see amino acid; neurotransmitter.... glutamic acid

(GAD) a common enzyme that, because of similarities to certain bacterial proteins, can provoke an autoimmune reaction against the beta cells of the pancreas (see islet cell antibodies) progressing to type 1 *diabetes mellitus.... glutamic acid decarboxylase

see bile acids.... glycocholic acid

a derivative of *histamine that was formerly used to test for acid secretion in the stomach in conditions involving abnormal gastric acid secretion, such as *Zollinger-Ellison syndrome.... histamine acid phosphate

a product formed during the metabolism of the amino acids phenylalanine and tyrosine. In normal individuals homogentisic acid is oxidized by the enzyme homogentisic acid oxidase. In rare cases this enzyme is lacking and a condition known as *alcaptonuria, in which large amounts of homogentisic acid are excreted in the urine, results.... homogentisic acid

an acid *mucopolysaccharide that acts as the binding and protective agent of the ground substance of connective tissue. It is also present in the synovial fluid around joints and in the vitreous and aqueous humours of the eye.... hyaluronic acid

(prussic acid) an intensely poisonous volatile acid that can cause death within a minute if inhaled. It has a smell of bitter almonds. See cyanide.... hydrocyanic acid

(5-HIAA) a metabolite of *serotonin, the most common secretion product of *carcinoid tumours. Measured over 24 hours in the urine, this is the most reliable screening test for such tumours.... 5-hydroxyindoleacetic acid

excessive plasma acidity due to an accumulation of lactic acid. This may be caused by a variety of illnesses, including heart failure or severe dehydration. It can also be caused by the accumulation of *biguanide drugs used for treating type 2 *diabetes mellitus, particularly when kidney failure is present. Biguanides (see metformin) should therefore not be used to treat patients who have established kidney disease or heart failure or who are dehydrated.... lactic acidosis

see essential fatty acid.... linolenic acid

a sulphur-containing compound that can be readily interconverted to and from its reduced form, dihydrolipoic acid. Lipoic acid functions in carbohydrate metabolism as one of the *coenzymes in the oxidative decarboxylation of pyruvate and other ?-keto acids.... lipoic acid

(LSD) an illegal hallucinogenic drug that was formerly used to aid treatment of certain psychological disorders. Side-effects include digestive upsets, dizziness, tingling, anxiety, sweating, dilated pupils, muscle incoordination and tremor. Alterations in sight, hearing, and other senses occur, psychotic effects, depression, and confusion are common, and tolerance to the drug develops rapidly. Because of these toxic effects, LSD is no longer used clinically. See Appendix 12 for a list of street names for illicit drugs.... lysergic acid diethylamide

(methylmalonic acidaemia, aminoacidopathy) a defect of amino acid metabolism causing an excess of methylmalonic acid in the urine and blood. There are two types: one is an *inborn error of metabolism due to a deficiency of the enzyme methylmalonyl-CoA mutase; the other is an acquired type due to deficiency of vitamin B12, which results in defective synthesis of adenosylcobalamin (a cofactor in this metabolic process).... methylmalonic aciduria

a strong corrosive mineral acid, HNO3, the concentrated form of which is capable of producing severe burns of the skin. Swallowing the acid leads to intense burning pain and ulceration of the mouth and throat. Treatment is by immediate administration of alkaline solutions, followed by milk or olive oil.... nitric acid

(n-3 fatty acids) polyunsaturated fatty acids with a double bond at the third carbon atom in the chain. Omega-3 fatty acids are essential for brain development and are also associated with many health benefits, including protection against heart disease and possibly stroke and inflammatory conditions. There are three major types: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The main source of EPA and DHA is fish oils. Vegetarians rely on EPA and DHA being synthesized by the body from dietary sources of ALA. See also essential fatty acids.... omega-3 fatty acids

see osmium tetroxide.... osmic acid

see fatty acid.... palmitic acid

(PAS reaction) a test for the presence of glycoproteins, polysaccharides, certain mucopolysaccharides, glycolipids, and certain fatty acids in tissue sections. The tissue is treated with periodic acid, followed by *Schiff’s reagent. A positive reaction is the development of a red or magenta coloration.... periodic acid–schiff reaction

see hydrocyanic acid.... prussic acid

see folate.... pteroylglutamic acid

(pyruvate) a compound, derived from carbohydrates, that may be oxidized via a complex series of reactions in the *Krebs cycle to yield carbon dioxide and energy in the form of ATP.... pyruvic acid

a *fatty acid in which all the carbon atoms are linked by single bonds and the molecule is unable to accept additional atoms (i.e. it cannot undergo addition reactions with other molecules). These fats occur mainly in animal and dairy products, and a diet high in these foods may contribute to a high serum cholesterol level, which may increase the risk of *coronary artery disease. Compare unsaturated fatty acid.... saturated fatty acid

an amino sugar. Sialic acid is a component of some *glycoproteins, *gangliosides, and bacterial cell walls.... sialic acid

see fatty acid.... stearic acid

a powerful corrosive acid, H2SO4, widely used in industry. Swallowing the acid causes severe burning of the mouth and throat and difficulty in breathing, speaking, and swallowing. The patient should drink large quantities of milk or water or white of egg; gastric lavage should not be delayed. Skin or eye contact should be treated by flooding the area with water.... sulphuric acid

see bile acids.... taurocholic acid

an *astringent used for a variety of skin conditions. It is also applied topically to produce sloughing, especially for the removal of warts.... trichloracetic acid

an antifungal agent, applied to the skin for the treatment of athlete’s foot.... undecenoic acid

a *fatty acid in which one (monounsaturated) or many (polyunsaturated) of the carbon atoms are linked by double bonds that are easily split in chemical reactions so that other substances can connect to them. These fats occur in fish and plant-derived foods, and a diet high in unsaturated fats is associated with low serum cholesterol levels. Compare saturated fatty acid.... unsaturated fatty acid

see sodium valproate.... valproic acid

(VMA) a metabolite of *catecholamines excreted in abnormal amounts in the urine in conditions of excess catecholamine production, such as *phaeochromocytoma. The measurement of VMA levels in a 24-hour urine sample was formerly used as a screening test for this condition, but in the UK it has been largely superseded by the urinary metanephrine test (see metanephrine and normetanephrine).... vanillylmandelic acid

(zolendronate) a *bisphosphonate drug that is used to treat Paget’s disease and malignant *hypercalcaemia and is also establishing a role in treating bone metastases, both in terms of symptom relief and preventing bone fractures.... zoledronic acid