Periodic Acid–schiff Reaction: From 1 Different Sources
(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.
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
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 DNA.... deoxyribonucleic 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 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
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
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 test introduced for the diagnosis of SYPHILIS by examination of the blood. It has now been largely supplanted by other, more speci?c tests.... wassermann reaction
See AGGLUTINATION.... widal reaction
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
An inherited condition causing recurrent bouts of fever. (See familial Mediterranean fever.)... periodic fever
(PCR) A method of rapidly copying DNA sequences so that they can be analysed.... polymerase chain reaction
See ASPIRIN.... acetylsalicyclic acid
Any undesirable or unwanted consequence of a preventive, diagnostic or therapeutic procedure.... adverse event / reaction
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
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
See CYANIDE POISONING.... prussic acid 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
Herbalists, phytotherapists, other practitioners and companies are required by the Committee on Safety of Medicines to report all adverse reactions associated with herbal products used in the treatment of disease in the UK within one month. Adverse reactions to over-the-counter alternative medicines should be reported using the yellow card scheme. (CSM., Current Problems 1986, No 16:477.) ... adverse reactions
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 active ingredient of many sunscreen preparations. Its abbreviation is.... para-aminobenzoic acid
A rare, inherited condition that affects young people. Periodic paralysis is characterized by episodes of muscle weakness, which vary in frequency from daily to every few years and last from a few minutes to a few hours. In some cases, there is a drop in the potassium levels in the blood; in others, the levels rise. A carbohydraterich meal may trigger an attack. The condition often clears up without treatment by age 40.... paralysis, periodic
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 method of demonstrating the presence of DNA in cell nuclei. The tissue section under investigation is first hydrolysed with dilute hydrochloric acid and then treated with *Schiff’s reagent. A purple coloration develops in the presence of DNA. [R. Feulgen (1884–1955), German chemist]... feulgen reaction
(Eisenmenger syndrome) a condition in which *pulmonary hypertension is associated with a *septal defect, so that blood flows from the right to the left side of the heart or from the pulmonary artery to the aorta. This allows blue blood, poor in oxygen, to bypass the lungs and enter the general circulation. This reduces the oxygen content of the arterial blood in the aorta and its branches, resulting in a patient with a dusky blue appearance (*cyanosis) and an increased number of red blood cells (*polycythaemia). There is no curative treatment at this stage, but the patient may be helped by the control of heart failure and polycythaemia. The condition may be prevented by appropriate treatment of the septal defect in early childhood before irreversible pulmonary hypertension develops. [V. Eisenmenger (1864–1932), German physician]... eisenmenger reaction
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 group of rare inherited disorders characterized by recurrent attacks of fever and inflammation in the absence of infection. They include familial Mediterranean fever (see polyserositis), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), and the cryopyrin-associated periodic syndrome (CAPS). Causative gene mutations have been identified.... hereditary periodic fever syndromes
see Jarisch-Herxheimer reaction.... herxheimer reaction
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
(Herxheimer reaction) exacerbation of the symptoms of syphilis that may occur on starting antibiotic therapy for the disease. The effect is transient and requires no treatment. [A. Jarisch (1850–1902), Austrian dermatologist; K. Herxheimer (1861–1944), German dermatologist]... jarisch–herxheimer reaction
a test for syphilis, in which antibodies specific to the disease are detected in a sample of the patient’s blood by means of a *precipitin reaction. This test is not as reliable as some. [R. L. Kahn (20th century), US bacteriologist]... kahn reaction
an aggravation of lumps on the skin caused by *leprosy, accompanied by fever and malaise.... lepra reaction
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 histochemical test for proteins, in which ninhydrin (triketohydrindene hydrate) is boiled with the test solution and gives a blue colour in the presence of amino acids and proteins.... ninhydrin reaction
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
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 reaction in which antibodies against the bacterium Streptococcus pneumoniae combine with the bacterial capsule, which becomes swollen and visible to light microscopy.... quellung reaction
(in psychoanalysis) a *defence mechanism by which unacceptable unconscious ideas are replaced in consciousness by their opposites. For instance, a man might make an ostentatious show of affection to someone for whom he has an unconscious hatred.... reaction formation
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
aqueous *fuchsin solution decolourized with sulphur dioxide. A blue coloration develops in the presence of aldehydes. [H. Schiff (1834–1915), German chemist]... schiff’s reagent
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
a condition in which attacks of sudden weakness and flaccidity occur in patients with *thyrotoxicosis, seen most often in males of Asian descent. The attacks last from hours to days; they can be prevented by potassium supplements and subsequent treatment of the thyrotoxicosis.... thyrotoxic periodic paralysis
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
a diagnostic test for typhus. A sample of the patient’s serum is tested for the presence of antibodies against the organism Proteus vulgaris. Although this relatively harmless organism is not the cause of typhus, it possesses certain antigens in common with the causative agent of the disease and can therefore be used instead of it in laboratory tests. Typhus is suspected if antibodies are found to be present. [E. Weil (1880–1922), German physician; A. Felix (1887–1956), Czech bacteriologist]... weil–felix reaction
(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
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