Prussic Acid Poisoning: From 1 Different Sources
See CYANIDE POISONING.
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
This illness is characterised by vomiting, diarrhoea and abdominal pain, and results from eating food contaminated with metallic or chemical poisons, certain micro-organisms or microbial products. Alternatively, the foods – such as undercooked red kidney beans or ?sh of the scombroid family (mackerel and tuna) – may contain natural posions. Food poisoning caused by chemical or metallic substances usually occurs rapidly, within minutes or a few hours of eating. Among micro-organisms, bacteria are the leading cause of food poisoning, particularly Staphylococcus aureus, Clostridium perfringens (formerly Cl. welchii), Salmonella spp., Campylobacter jejuni, and Escherichia coli O157.
Staphylococcal food poisoning occurs after food such as meat products, cold meats, milk, custard and egg products becomes contaminated before or after cooking, usually through incorrect handling by humans who carry S. aureus. The bacteria produce an ENTEROTOXIN which causes the symptoms of food poisoning 1–8 hours after ingestion. The toxin can withstand heat; thus, subsequent cooking of contaminated food will not prevent illness.
Heat-resistant strains of Cl. perfringens cause food poisoning associated with meat dishes, soups or gravy when dishes cooked in bulk are left unrefrigerated for long periods before consumption. The bacteria are anaerobes (see ANAEROBE) and form spores; the anaerobic conditions in these cooked foods allow the germinated spores to multiply rapidly during cooling, resulting in heavy contamination. Once ingested the bacteria produce enterotoxin in the intestine, causing symptoms within 8–24 hours.
Many di?erent types of Salmonella (about 2,000) cause food poisoning or ENTERITIS, from eight hours to three days after ingestion of food in which they have multiplied. S. brendeny, S. enteritidis, S. heidelberg, S. newport and S. thompson are among those commonly causing enteritis. Salmonella infections are common in domesticated animals such as cows, pigs and poultry whose meat and milk may be infected, although the animals may show no symptoms. Duck eggs may harbour Salmonella (usually S. typhimurium), arising from surface contamination with the bird’s faeces, and foods containing uncooked or lightly cooked hen’s eggs, such as mayonnaise, have been associated with enteritis. The incidence of human S. enteritidis infection has been increasing, by more than 15-fold in England and Wales annually, from around 1,100 a year in the early 1980s to more than 32,000 at the end of the 1990s, but has since fallen to about 10,000. A serious source of infection seems to be poultry meat and hen’s eggs.
Although Salmonella are mostly killed by heating at 60 °C for 15 minutes, contaminated food requires considerably longer cooking and, if frozen, must be completely thawed beforehand, to allow even cooking at a su?cient temperature.
Enteritis caused by Campylobacter jejuni is usually self-limiting, lasting 1–3 days. Since reporting of the disease began in 1977, in England and Wales its incidence has increased from around 1,400 cases initially to nearly 13,000 in 1982 and to over 42,000 in 2004. Outbreaks have been associated with unpasteurised milk: the main source seems to be infected poultry.
ESCHERICHIA COLI O157 was ?rst identi?ed as a cause of food poisoning in the early 1980s, but its incidence has increased sharply since, with more than 1,000 cases annually in the United Kingdom in the late 1990s. The illness can be severe, with bloody diarrhoea and life-threatening renal complications. The reservoir for this pathogen is thought to be cattle, and transmission results from consumption of raw or undercooked meat products and raw dairy products. Cross-infection of cooked meat by raw meat is a common cause of outbreaks of Escherichia coli O157 food poisoning. Water and other foods can be contaminated by manure from cattle, and person-to-person spread can occur, especially in children.
Food poisoning associated with fried or boiled rice is caused by Bacillus cereus, whose heat-resistant spores survive cooking. An enterotoxin is responsible for the symptoms, which occur 2–8 hours after ingestion and resolve after 8–24 hours.
Viruses are emerging as an increasing cause of some outbreaks of food poisoning from shell?sh (cockles, mussels and oysters).
The incidence of food poisoning in the UK rose from under 60,000 cases in 1991 to nearly 79,000 in 2004. Public health measures to control this rise include agricultural aspects of food production, implementing standards of hygiene in abattoirs, and regulating the environment and process of industrial food production, handling, transportation and storage.... food poisoning
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
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
See SEPTICAEMIA.... blood-poisoning
See DNA.... deoxyribonucleic acid
A valuable antistaphylococcal antibiotic used both orally and topically. It is particularly useful in osteomyelitis (see BONE, DISORDERS OF).... fusidic acid
Lead and lead compounds are used in a variety of products including petrol additives (in the UK, lead-free petrol is now mandatory), piping (lead water pipes were once a common source of poisoning), weights, professional paints, dyes, ceramics, ammunition, homeopathic remedies, and ethnic cosmetic preparations. Lead compounds are toxic by ingestion, by inhalation and, rarely, by skin exposures. Metallic lead, if ingested, is absorbed if it remains in the gut. The absorption is greater in children, who may ingest lead from the paint on old cots
– although lead-containing paints are no longer used for items that children may be in contact with.
Acute poisonings are rare. Clinical features include metallic taste, abdominal pain, vomiting, diarrhoea, ANOREXIA, fatigue, muscle weakness and SHOCK. Neurological effects may include headache, drowsiness, CONVULSIONS and COMA. Inhalation results in severe respiratory-tract irritation and systemic symptoms as above.
Chronic poisonings cause gastrointestinal disturbances and constipation. Other effects are ANAEMIA, weakness, pallor, anorexia, insomnia, renal HYPERTENSION and mental fatigue. There may be a bluish ‘lead line’ on the gums, although this is rarely seen. Neuromuscular dysfunction may result in motor weakness and paralysis of the extensor muscles of the wrist and ankles. ENCEPHALOPATHY and nephropathy are severe effects. Chronic low-level exposures in children are linked with reduced intelligence and behavioural and learning disorders.
Treatment Management of patients who have been poisoned is supportive, with removal from source, gastric decontamination if required, and X-RAYS to monitor the passage of metallic lead through the gut if ingested. It is essential to ensure adequate hydration and renal function. Concentrations of lead in the blood should be monitored; where these are found to be toxic, chelation therapy should be started. Several CHELATING AGENTS are now available, such as DMSA (Meso-2,3dimercaptosuccinic acid), sodium calcium edetate (see EDTA) and PENICILLAMINE. (See also POISONS.)... lead poisoning
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
See FUNGUS POISONING.... mushroom poisoning
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
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
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
Around 2,000 mushrooms (toadstools) grow in England, of which 200 are edible and a dozen are classi?ed as poisonous. Not all the poisonous ones are dangerous. It is obviously better to prevent mushroom poisoning by ensuring correct identi?cation of those that are edible; books and charts are available. If in doubt, do not eat a fungus.
Severe poisoning from ingestion of fungi is very rare, since relatively few species are highly toxic and most species do not contain toxic compounds. The most toxic species are those containing amatoxins such as death cap (Amanita phalloides); this species alone is responsible for about 90 per cent of all mushroom-related deaths. There is a latent period of six hours or more between ingestion and the onset of clinical effects with these more toxic species. The small intestine, LIVER and KIDNEYS may be damaged – therefore, any patient with gastrointestinal effects thought to be due to ingestion of a mushroom should be referred immediately to hospital where GASTRIC LAVAGE and treatment with activated charcoal can be carried out, along with parenteral ?uids and haemodialysis if the victim is severely ill. In most cases where effects occur, these are early-onset gastrointestinal effects due to ingestion of mushrooms containing gastrointestinal irritants.
Muscarine is the poisonous constituent of some species. Within two hours of ingestion, the victim starts salivating and sweating, has visual disturbances, vomiting, stomach cramps, diarrhoea, vertigo, confusion, hallucinations and coma, the severity of symptoms depending on the amount eaten and type of mushroom. Most people recover in 24 hours, with treatment.
‘Magic’ mushrooms are a variety that contains psilocybin, a hallucinogenic substance. Children who take such mushrooms may develop a high fever and need medical care. In adults the symptoms usually disappear within six hours.
Treatment If possible, early gastric lavage should be carried out in all cases of suspected poisoning. Identi?cation of the mushroom species is a valuable guide to treatment. For muscarine poisoning, ATROPINE is a speci?c antidote. As stated above, hospital referral is advisable for people who have ingested poisonous fungi.... fungus poisoning
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
The toxic effect of mercury has been known since days of the medieval alchemists. Charles II presented all the symptoms we now recognise as mercurial poisoning, presumably the result of medication received over many years. Its symptoms simulate multiple sclerosis, when chronic. They are: constant fatigue, pins and needles in the limbs, resting tremor, nausea, dizziness, ataxia, pains in the bones and joints, drooling (excessive salivation), blue line along the gums. In children they may include all kinds of vague aches and pains, chorea, hyperthyroidism and facial neuralgia. Weakness, walking difficulties, metallic taste in the mouth, thirst, mental deterioration. It is now known to cause a number of serious nerve dystrophies.
Mercury has an affinity for the central nervous system. Soon it concentrates in the kidney causing tubular damage. A common cause is the mercurial content (50 per cent) in the amalgam fillings in teeth which, under certain conditions, release a vapour. Fortunately, its use in dentistry is being superceded by an alternative composite filling.
A common cause of poisoning was demonstrated in 1972 when 6,000 people became seriously ill (600 died) from eating bread made from grain treated with a fungicide containing methylmercury. For every fungus in grain there is a mercuric compound to destroy it. The seed of all cereal grain is thus treated to protect its power of germination.
Those who are hypersensitive to the metal should as far as possible avoid button cells used in tape recorders, cassette players, watch and camera mechanisms. As the mercury cells corrode, the metal enters the environment and an unknown fraction is converted by micro organisms to alkylmercury compounds which seep into ground waters and eventually are borne to the sea. When cells are incinerated, the mercury volatilises and enters the atmosphere. (Pharmaceutical Journal, July 28/1984)
Mercury poisoning from inhalation of mercury fumes goes directly to the brain and pituitary gland. Autopsies carried out on dentists reveal high concentrations of mercury in the pituitary gland. (The Lancet, 5-27-89,1207 (letter))
Treatment. For years the common antidote was sulphur, and maybe not without reason. When brought into contact sulphur and mercury form an insoluble compound enabling the mercury to be more easily eliminated from the body. Sulphur can be provided by eggs or Garlic.
Old-time backwoods physicians of the North American Medical School used Asafoetida, Guaiacum and Echinacea. German pharmacists once used Bugleweed and Yellow Dock. Dr J. Clarke, USA physician recommends Sarsaparilla to facilitate breakdown and expulsion from the body.
Reconstructed formula. Echinacea 2; Sarsaparilla 1; Guaiacum quarter; Asafoetida quarter; Liquorice quarter. Dose: Liquid Extracts: 1 teaspoon. Tinctures: 2 teaspoons. Powders: 500mg (two 00 capsules or one-third teaspoon). Thrice daily.
Chelation therapy.
Formula. Tinctures. Skullcap 2-15 drops; Pleurisy root 20-45 drops; Horehound 5-40 drops. Mercurial salivation. Thrice daily. (Indian Herbology of North America, by Alma Hutchens) Dental fillings: replace amalgam with safe alternative – ceramic, etc. Evidence of a link between tooth fillings containing mercury and ME has caused the use of dental amalgam to be banned in Sweden. ... mercury poisoning
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
See ASPIRIN.... acetylsalicyclic acid
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
ASPIRIN is a commonly available analgesic (see ANALGESICS) which is frequently taken in overdose. Clinical features of poisoning include nausea, vomiting, TINNITUS, ?ushing, sweating, HYPERVENTILATION, DEHYDRATION, deafness and acid-base and electrolyte disturbances (see ELECTROLYTES). In more severe cases individuals may be confused, drowsy and comatose. Rarely, renal failure (see KIDNEYS, DISEASES OF), PULMONARY OEDEMA or cardiovascular collapse occur. Severe toxicity may be delayed, as absorption of the drug may be prolonged due to the formation of drug concretions in the stomach. Treatment involves the repeated administration of activated CHARCOAL, monitoring of concentration of aspirin in the blood, and correction of acid-base and electrolyte imbalances. In more severely poisoned patients, enhanced excretion of the drug may be necessary by alkalinising the urine (by intravenous administration of sodium bicarbonate – see under SODIUM) or HAEMODIALYSIS.... aspirin poisoning
See ATROPINE; BELLADONNA POISONING.... atropine poisoning
Atropa belladonna (deadly nightshade) is a relatively rare plant and severe poisoning is not common. The berries, which are black, ripen from August to October and are the most commonly ingested part of the plant. However, all parts of the plant are toxic. The berries contain ATROPINE and other unidenti?ed ALKALOIDS, the leaves HYOSCINE and atropine, and the roots hyoscine. All these alkaloids have an ANTICHOLINERGIC e?ect which may cause a dry mouth, dilated pupils with blurred vision, TACHYCARDIA, HALLUCINATIONS and PYREXIA. There may also be ATAXIA, agitation, disorientation and confusion. In severe cases there may be CONVULSIONS, COMA, respiratory depression and ARRHYTHMIA. Clinical effects may be delayed in onset for up to 12 hours, and prolonged for several days. Treatment is supportive.... belladonna poisoning
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
Ergot poisoning, or ergotism, occasionally results from eating bread made from rye infected with the fungus, Claviceps purpurea. Several terrible epidemics (St Anthony’s Fire), characterised by intense pain and hallucinations, occurred in France and Germany during the Middle Ages (see ERYSIPELAS). Its symptoms are the occurrence of spasmodic muscular contractions, and the gradual production of gangrene in parts like the ?ngers, toes and tips of the ears because of constriction of blood vessels and therefore the blood supply.... ergot poisoning
A potent diuretic, with a rapid onset, and a short duration (4–6 hours), of action. (See THIAZIDES; DIURETICS.)... ethacrynic 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
Poisoning by saxitoxin, a toxin present in some shellfish, usually in tropical or subtropical seas. Symptoms of respiratory arrest, or brain involvement occur in some 8% of cases, resulting in death. Saxitoxin is related to tetrodotoxin.... paralytic shellfish poisoning
This occurs from eating poorly preserved scromboid ?sh such as tuna, mackerel and other members of the mackerel family. In such ?sh, a toxic histamine-like substance is produced by the action of bacteria or histidine, a normal component of ?sh ?esh. This toxin produces nausea, vomiting, headache, upper abdominal pain, di?culty in swallowing, thirst, itching and sometimes URTICARIA. The condition settles as a rule in 12 hours. ANTIHISTAMINE DRUGS sometimes ameliorate the condition.... scrombotoxin poisoning
See POISONS.... self-poisoning
In the United Kingdom this occurs in two main forms. Shell?sh may be the cause of typhoid fever (see ENTERIC FEVER) as a result of their contamination by sewage containing the causative organism. They may also be responsible for what is known as paralytic shell?sh poisoning. This is caused by a toxin, or poison, known as saxotoxin, which is present in certain planktons which, under unusual conditions, multiply rapidly, giving rise to what are known as ‘red tides’. In these circumstances the toxin accumulates in mussels, cockles and scallops which feed by ?ltering plankton. The manifestations of such poisoning are loss of feeling in the hands, tingling of the tongue, weakness of the arms and legs, and di?culty in breathing. There is also growing evidence that some shell?sh poisoning may be due to a virus infection. (See also FOOD POISONING.)... shellfish poisoning
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
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)
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
The toxic effects of chemicals present in some defoliant weedkillers. Ingesting chlorates can cause kidney and liver damage, corrosion of the intestine, and methaemoglobinaemia (a chemical change in haemoglobin in the blood). Small doses of chlorates can prove fatal. Symptoms of poisoning include ulceration in the mouth, abdominal pain, and diarrhoea.... chlorate poisoning
The toxic effects that occur as a result of swallowing the cleaning agents in shampoos, laundry powders, and cleaning liquids.... detergent poisoning
The active ingredient of many sunscreen preparations. Its abbreviation is.... para-aminobenzoic acid
See food poisoning.... shellfish poisoning
See mushroom poisoning.... toadstool poisoning
see aspirin.... acetylsalicylic acid
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
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
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
(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
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
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
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