Starting with A for "ACE inhibitor" and continuing through to Y for "Yolk Sac Tumour", we give you succinct explanations for scientific and medical terms in clear and simple words.
- MacroangiopathyDisease of large and intermediate blood vessels (arm or leg vessels, stomach vessels, coronary vessels, the vessels which serve the brain), mostly arteriosclerosis. Cf. microangiopathy.
- macrocyticcharacterised by cells that are larger than normal
- MacrophagesMacrophages are specialised white blood cells which are capable of, taking up, destroying and metabolising solid particles such as bacteria and other microorganisms, cell debris or foreign bodies (cf. phagocytes). The cells are formed in the bone marrow and then migrate into different tissues, where they develop into fixed macrophages which are typical of the tissue and where they are of central importance in immune defence.
- Magnetic ResonanceSee Magnetic Resonance Therapy.
- Magnetic resonance tomographysee nuclear spin tomography.
- MalaciaMalacia, softening, e.g. osteomalacia, chondromalacia (disease of cartilage tissue).
- MaldigestionDisturbance in digestion.
The most frequent causes are deficiencies in digestive enzymes (see enzymes), e.g. in diseases of the pancreas and gall bladder (e.g. when there are obstacles to bile flow). Other causes are food allergies (e.g. to milk proteins) and malformation of the lymph vessels.
Large quantities of faeces or fatty faeces
- MalignancyA broad expression for a malignant tumour.
- malignantThe opposite of benign.
- Malignant hypertensionClinical term for high blood pressure (hypertension) with constant elevation of the diastolic blood pressure to more than 120 mm Hg, independently of the cause.
- Malignant MelanomaA tumour which occurs on the skin or, more rarely, mucous membrane. Malignant melanoma originates in the pigment forming cells in the skin or, more rarely, in the mucous membrane, the choroids of the eye or the cerebral membranes. This often arises spontaneously from skin which has previously been fully normal or from a birthmark which is already present.
The number of cases of malignant melanoma has been clearly increasing in recent years. It is thought that the reason for this is greater exposure to the sun, particularly if sunburn occurs frequently.
Diagnosis: Early recognition on the basis of the following symptoms: rapid increase in the size of a birth mark, development of a raised surface, increase in pigmentation, red and inflamed area round a birthmark, formation of an ulcer, swelling of the connected lymph nodes and subjective symptoms such as pain, itch and restlessness in the tumour. Metastases are searched for using X-rays and ultrasound.
Tumour Classification: The danger from the tumour is evaluated from the degree of metastasis formation and the thickness of the tumour. The rate of growth is also determined and the involvement of vessels is evaluated.
Therapy: Surgical removal of the tumour, allowing a clear safety zone of 1-3 cm and cutting down to the muscle fibres. If metastases have formed, drug treatment (chemotherapy) and immunotherapy are necessary. Radiotherapy may be useful in severe cases.
Prognosis: The chances of cure depend on the degree of metastasis formation and on the thickness of the tumour and its site. The prognosis is regarded as unfavourable for malignant melanoma on the skin of the head, mucous membranes, retina, sexual organs (better for women) and, for example, the extremities.
- Maltosealso known as maltobiose or malt sugar
Disaccharide which is composed of two molecules of glucose chemically connected in a specific manner. Maltose is an intermediary product in the digestive metabolism of polysaccharides, e.g. of starch and glycogen.
- MammaThe scientific term for the female breast.
- Mammary BiopsyIn a mammary biopsy, an attempt is made to remove a suspicious region or knot from the mamma as completely as possible, so that the tissue can be examined in the laboratory. In this way, the malignancy of the nodule can be established, which would otherwise not have been possible with certainty.
- Mammary CarcinomaAlso breast cancer
This is the most frequent malignant tumour in women and mostly occurs between 45 and 70 years of age.
Symptoms: Mostly painless, although the nodules are clearly palpable. Early symptoms are suspicious findings on palpation, which are usually evident in cancer screening tests and in regular self-examination of the breast. There can also, for example, be changes in the skin (retraction of the skin or a hardening which cannot be displaced, coarse pores) or retraction of the nipple, secretion from the mammary glands and others.
Clinical Course: Depends on the stage of the tumour on diagnosis, particularly if the lymph nodes are affected (see metastases) and malignancy of the tumour (see grading).
Diagnosis: Palpation, ultrasound diagnosis, X-ray investigation (mammography), nuclear spin tomography and examination of tissue samples (see mammary biopsy).
Therapy: 1. Surgical removal of the affected regions. The extent of removal can depend on the localisation and the tumour stage; removal of the whole breast may sometimes be necessary. If the breast is retained (lumpectomy) additional radiotherapy is usually advisable. 2. If the tumour is malignant (from grades G2-G3), the whole body is treated, either with drugs, such as a) cytostatic drugs, b) hormones for tumours which have hormone receptors, or radiotherapy is performed.
Aftercare: In the first three years a quarterly check-up is necessary (X-ray), as most recurrences and metastases occur in this period.
- Mammary TumoursTumours of the female breast (mamma);
1. Benign mammary tumours: occur mostly in younger women, particularly fibroadenoma (originate in the connective and glandular tissue and tend to become malignant), mammary duct papilloma and adenoma.
2. Malignant mammary tumours: in particular mammary carcinoma or more rarely Pagets disease, which is adenomcarcinoma of the lactatory glands. Forms of mastopathy are regarded as precancerosis.
- Marble Bone DiseaseAlso known as osteopetrosis familiaris, osteosclerosis congenita diffusa or Albers-Schönberg disease.
Hereditary disease of the osteoclasts, the cells which break down bone substance. The disturbance in the activity of the osteoclasts is accompanied by unrestricted bone generation or regeneration and leads to a restriction in natural bone metabolism and thus to an increase in bone density (see disturbances in ossification).
The symptoms are very variable. The mildest forms of the disease are found by chance on X-rays, as a narrowing in the medullar cavity, typically as three apparent layers in the vertebral body or as osteosclerosis. Marble bone disease leads to bone pains. Spontaneous bone fractures and inflammation of the bone marrow occur frequently. Severe forms of the disease occur even in young babies, causing malfunction of the bone marrow, which then leads to anaemia and other blood diseases and to liver and spleen enlargement. The disease can also lead to blindness by pinching of the optic nerve, poor hearing and muscular spasm. This is the result of lack of calcium, as the release of ionised calcium from bone is hindered.
Bone marrow transplantation. Caution! Danger of fractured bones during operations, for example of the jaw bone during operative removal of a tooth.
- Maturity-Onset diabetesType 2 diabetes
- mean corpuscular hemoglobin (MCH)average weight of hemoglobin in red blood cells; normal MCH is 27 to 31 pg
- mean corpuscular hemoglobin concentration (MCHC)average concentration of hemoglobin in red blood cells; normal MCHC is 32% to 36%
- mean corpuscular volume (MCV)average volume of red blood cells in a blood sample; normal MCV is 80 to 100 fl
- megaloblastic anemiaa type of anemia in which the erythrocytes produced are immature and abnormally large; megaloblastic anemia is usually associated with vitamin B12 or folic acid deficiency
- MeningeomaSlowly growing and benign tumour, which originates in the cerebral membranes and in the membranes of the spine (spinal meninx). Meningeoma can become malignant . It mostly occurs between 35 and 50 years of age. About 25% of all brain tumours are meningeomas.
Symptoms: Depending on the site, headache, epileptic attacks, changes in personality, forgetfulness and other symptoms.
Diagnosis: X-rays of the skull may show changes in the skull bones, computer tomography, magnetic resonance tomography, examination of the blood vessels of the brain (angiography).
Therapy: Operation, possibly radiotherapy.
- MenopauseTime of the last spontaneous monthly bleeding in the woman. This is defined so that for one subsequent year there is no bleeding from the womb due to ovarian activity. Menopause mostly occurs between age 45 and 55.
- Menopause syndromealso known as the vegetative climacterium syndrome
Typical combination of hot flushes, giddiness and sweating attacks which usually occurs after the menopause. Psychological or nervous problems are also evident, including irritability, listlessness, lack of energy and sleep problems. Physical problems may include involution (decrease in size) of the genitals and breasts, overweight and osteoporosis. The menopause syndrome can already occur in the period immediately before the menopause or after operative removal of the ovaries from younger women.
- MesotheliomaMalignant tumour of the pleura, pericardium or the peritoneum. Cf. Pleural Mesothelioma.
- Metabolic controlEstablishment of the dose of drugs which is most effective for the individual during long term treatment for metabolic disease.
- MetabolismSum total of all chemical reactions in the organism which are necessary for life. Components of the food consumed are used for either assimilation or dissimilation. Assimilation means the assembly of body substances from components which are absorbed after digestion. Dissimilation means the use of food components or compounds produced by assimilation to produce energy to support life. Many metabolic reactions run in cycles and are regulated at different levels. In the living organism substances are continuously being broken down and built up. Together this is known as substance turnover.
- MetastasisThe general meaning of metastasis is the transfer of cells, such as tumour cells or pathogens, or poisons from a local centre or focus of disease to another site, which can be quite distant, and that a second focus of disease is initiated there. The term is used in a more restricted sense for the metastasis of tumours, particularly malignant tumours. Tumour cells are then spread and daughter tumours are formed. A distinction is made between local metastases, which are in the vicinity of the primary tumour, regional metastases, which are in the next group of lymph nodes in the lymph draining area, and distant metastases. The tumour cells can, for example, be transferred in the blood circulation or through the lymph ducts.
- Methods for determining blood sugarEnzymatic methods for the determination of the concentration of glucose in blood (cf. enzymes). The glucose content can be determined by changes in absorption or staining after enzyme reactions.
1. Semi-quantitative rapid test (test strip). Principle: Glucose oxidase-peroxidase method; 2. Quantitative methods: a) Hexokinase method: Optical test after the conversion of glucose by hexokinase and glucose-6-phosphate dehydrogenase; b) Glucose-dehydrogenase method: Optical test after conversion with glucose dehydrogenase; c) Glucose-oxidase-peroxidase method; Glucose oxidase produces hydrogen peroxide when it oxidises glucose. The hydrogen peroxide is then detected with a dye reaction which is coupled to peroxidase; d) Glucose-oxidase method: Amperometric determination of hydrogen peroxide formed from membrane bound glucose oxidase in a flow-through cell.
- microalbuminuriaalbumin excretion above the normal range but below the level of detection by routine tests for total protein
- MicroangiopathyDisease caused by the narrowing of small or terminal arteries and their occlusion by a thrombosis.
1. Diabetic microangiopathy, typical late symptoms of diabetes mellitus (type 2 diabetes and type 1 diabetes). The retina, kidneys (diabetic glomerulosclerosis) and small peripheral vessels are affected. The results include disturbances in the perfusion of terminal parts of the body, such as the hands, feet and nose, and the death of tissue, such as diabetic gangrene of the foot. The origin of the disease is unclear. Histological studies have found that the basal membrane of the capillaries is thickened, that there are bulges in the small vessels and that there is proliferation of the cells in the innermost layer of the vessels. The extent of the diabetic microangiopathy is normally related to the severity and duration of the abnormalities in fat and sugar metabolism. 2. Microangiopathy in scleroderma, which is a disease of connective tissue and blood vessels caused by overactivity of the immune system and which causes occlusion of the arteries in the fingers and hands, rarely in the feet.
- MicroarrayMicroarrays contain up to more than a million of probes, single strands of genetic material, which are arrayed on a very small surface. Each strand resides in an assigned place on the underlying grid and allows to study many different genes at the same time. Microarrays can assist in identifying inheritable genetic variations, for example the ones which may cause individuals to metabolise certain drugs more or less efficiently.
- MicrobiologyMicrobiology is concerned with the investigation of microscopic creatures i.e microorganisms. These include algae, bacteria, fungi and viruses. Purely medical microbiology focuses on pathological microorganisms and their effect on other living beings.
- microcyticcharacterised by cells that are smaller than normal
- Milk acid acidosissee lactate acidosis
- Milkman syndromealso known as the decalcification syndrome
Multiple spontaneous complete or partial fatigue fractures, with formation of an uncalcified callus (Looser transformation zones. The fractures are often symmetrical and may be accompanied by a decrease in blood phosphate, an increase in urinary phosphate excretion and an increase in serum alkaline phosphatase. The cause of the milkman syndrome may be unknown or it may be the result of rickets, osteoporosis or osteomalacia.
- Mineralsalso known as mineral substances
Minerals in the body include calcium, phosphorus, sodium, sulphur and many others. They are taken up in food and fulfil various important functions, e.g. in water and salt balance and in the formation of bones and teeth. An inadequate supply of minerals leads to symptoms of deficiency. Cf. demineralisation.
- modified intent-to-treat (MITT)refers to all randomised patients in a study except those excluded on the basis of prespecified baseline criteria
- MoleculeA molecule is the smallest particle of a chemical compound and consists of two or more atoms. The term macromolecule normally means a molecule with more than 1000 atoms.
- monogenic (monogenic disease)A monogenic disease is a condition caused by a defect in a single gene. Usually these are inherited diseases. About 6000 such monogenic inherited diseases have already been described, including severe combined immunodeficiency, muscular dystrophy and amyotrophic lateral sclerosis (motor neurone disease, Lou Gehrigs disease) . Since the same gene can undergo different mutations, even monogenic diseases can vary in severity. Conditions caused by defects in several genes are called polygenic diseases.
- Monosaccharidesalso known as simple sugars
Monosaccharides are the smallest units of the carbohydrates, which cannot be further broken down by enzymatic hydrolysis; polyvalent alcohols with ketone or aldehyde groups.
1. Aldoses: These have an aldehyde group on carbon atom 1 (C1) (e.g. glucose, ribose). 2. Ketoses: These have a ketone group on C2 (e.g. fructose, ribulose). Depending on the number of carbon atoms, trioses, tetroses, pentoses, hexoses and heptoses are distinguished. Glucose, fructose, galactose, ribose and desoxyribose are monosaccharides which are important in metabolism.
- morphologythe form and structure of an organism or any of its parts
- MRISee Nuclear Spin Tomography.
- MRTAbbreviation for magnetic resonance tomography, also known as nuclear spin tomography.
- mutagenesisthe occurrence of a genetic mutation
- myalgiadiffuse muscle pain
- myelodysplastic syndromesdiseases in which the bone marrow does not function normally, affecting the production of all three major types of blood cells: red blood cells, white blood cells and platelets
- myelosuppressiveinhibiting blood cell production
- Myocardial infarctionalso known as heart muscle infarction
Death of tissue in a region of the heart muscle. A myocardial infarction is an acute complication of inadequate perfusion of the coronary arteries, which is mostly already present.
Continuous critically deficient perfusion of the coronary arteries when the previous perfusion has also bee inadequate (coronary insufficiency). Alternatively continuous spasm of the coronary vessels. Myocardial infarction frequently occurs during or after physical or psychological stress. It is the result of an increase in the oxygen requirement of heart muscle or of an cute interruption of perfusion, particularly when the blood vessels are hardened and constricted (arteriosclerosis) and a coronary artery is occluded by a blood clot.
Severe feeling of pressure behind the breastbone, with chest pains and spreading pain, like that in angina pectoris, but usually more intense. The pain is mostly accompanied by anxiety and the fear of destruction. Frequent symptoms include low blood pressure, rapid and low pulse, pallor and cold sweat, nausea and sometimes vomiting.
1. On the basis of the symptoms; 2. Electrocardiography (ECG); 3. Detection in the blood of raised concentrations of enzymes which are specific to heart muscle; 4. Increases in the blood concentrations of the muscle proteins troponin T and troponin I; 5. other laboratory tests include increased erythrocyte sedimentation rate, increased concentrations of blood platelets and raised blood sugar.
1. First Aid: Pain is reduced with analgesics and with nitroglycerin, which also widens blood vessels (see organic nitrates). Acetylsalicylic acid inhibits platelet aggregation and heparin inhibits blood aggregation. If there are no contraindications and the infarction has occurred less than 6 hours previously, the blood clot should be dissolved as soon as possible or the occluded coronary vessel expanded with a balloon catheter. 2. After the acute therapy has been completed, a heart catheter investigation (coronary angiography) is carried out to assess further therapeutic possibilities. If the course is complicated the catheterisation can be carried out earlier.
- MyomaMyomas are benign tumours which consist predominantly of muscle fibres. There are three forms:
1. Leiomyomas, which originate in the smooth muscle fibres in the intestine and often form nodular tumours with well defined edges (e.g. in the womb).
2. Fibromyomas, which consist of muscle fibres and a lot of connective tissue.
3. Rhabdomyomas, which originate from the cross-striped (striomuscular) musculature of the locomotive system or of the heart (rare).
- MyososarcomaMalignant tumour of muscle tissue (cf. sarcoma). The muscles of the locomotor system and of the intestinal muscles may be affected.
Glossary entries: Roche and Walter de Gruyter, Berlin