Glossary
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.
- GallbladderThe gallbladder is a pear-shaped thin-walled mucosal sack, in which bile is stored. It lies under the liver and is about 10 cm long and 4 cm wide. The gallbladder contains ca. 40-80 ml fluid when it is full, which corresponds to about a quarter to a third of a full glass of juice.
- Gastric bypassNow very rarely used operative technique to reduce weight in cases of extreme overweight when all other methods have failed. The stomach reservoir is reduced to a fifth by lateral separation, followed by restoration of the stomach-intestinal passage.
- Gastric CarcinomaMalignant tumour of the stomach, which originates in the cells of the mucous membrane of the stomach. It mostly occurs between 60 and 70 years of age and is somewhat more frequent in men than in women (ratio of 1.5 to 1).
Causes: Unclear, possible predisposing factors include: 1. Environmental and nutritional factors (nitrosamines, benzpyrene, deficiency of vitamin A or of ascorbic acid); 2. Genetic factors; 3. Gastritis with infections from Helicobacter pylori; 4. Partial gastric resection; 5. Mènètrier syndrome; 6. Certain gastric polyps.
Spread:
1. The carcinoma can spread in the vicinity, into the suspensory ligaments and into neighbouring organs, such as the oesophagus, liver, spleen, pancreas, colon and diaphragm;
2. Spread into the abdominal cavity and ovaries;
3. Through the lymph ducts into the neighbouring lymph nodes;
4. Through the blood vessels into the liver, lungs, skeleton and brain.
Symptoms: Unspecific symptoms such as the so-called sensitive stomach, lack of appetite, intolerance for certain foods, nausea, vomiting, feelings of pressure and fullness, problems in swallowing, bleeding.
Diagnosis: Gastroscopy with biopsy (tissue sample), X-rays with contrast medium, ultrasound investigation (can be through the oesophagus), computer tomography (CT), X-ray investigation of the lungs (for possible metastases), possible operation to evaluate the tumour.
Therapy: Gastric carcinoma is treated with an operation for partial removal of the stomach (partial gastric resection), possibly also with partial removal of the diaphragm and the surrounding lymph nodes. Even if cure is not possible, an operation can alleviate the symptoms (palliative operation). Possibly chemotherapy or radiotherapy after the operation.
Prognosis: The 5-year survival rate after the operation is between 20 and 30%. - Gastric plastic surgerysee gastroplasty
- Gastric SarcomaMalignant tumour which originates in the connective tissue in the stomach 8cf. sarcoma). This is a rare malignant tumour of the stomach, making up about 1% of all stomach tumours. Gastric carcinoma is more frequent. The symptoms, diagnosis and therapy are as with gastric carcinoma.
- Gastric Tumours1. Benign gastric tumours: relatively rare tumours of the stomach, which form no metastases, only grow slowly and which do not spread in the vicinity. These are mostly tumours of the fat tissue (lipomas), connective tissue (fibromas), nervous tissue (neurinomas), muscle tissue (leiomyomas) or glandular tissue (adenomas).
2. Malignant tumours: Frequently gastric carcinoma, more rarely gastric sarcoma and carcinoid. - Gastroplastyalso known as gastric plastic surgery
Operative procedure which is only used in cases of extreme overweight and only when other conventional methods to reduce weight have been exhausted. The mechanical reduction of the gastric reserve rapidly produces a feeling of fullness or satiety.
Methods
1. Vertically bandaged gastric plastic surgery with a vertical row of stitches; a plastic band or ring hinders the expansion of the newly created stomach outlet. 2. Gastric banding: Placement of a flexibly silicon band by gastroscopy. The band is wound and closed a small distance below the stomach outlet. The extension of the band and the resulting changes in gastric passage may be adjusted with a subcutaneous port.
Prognosis
If accompanied by dietetic advice and psychotherapeutic support weight losses of 30-70 kg are possible. - Genealso know as hereditary factor, hereditary unit or hereditary trait
A gene is the functional unit which contains the genetic information for a gene product such as an enzyme. Genes are contained in the chromosomes in a linear sequence. Several genes can participate together in the formation of a characteristic or a gene can influence the degree of different characteristics. Cf. DNA
- Genetic diseasesalso known as hereditary diseases or conditions
Hereditary diseases which either occur more frequently than expected in a family or, as a result of spontaneous mutation, occur for the first time in a family which has previously been unaffected. Genetic diseases are observed as physical, mental or combined abnormalities. Depending on their extent, they cannot always be distinguished from acquired conditions. Genetic changes which do not necessarily lead to diseases are probably very much more frequent. These may cause a disease only when there are additional external factors, such as drugs, infections or factors linked to nutrition. Genetic diseases are often due to the lack of or changes in a single enzyme which is involved in metabolism. Genetic diseases may become evident at an early age or only late in life. Aside from enzyme deficiencies, changes in other important proteins can lead to genetic diseases, such as those related to haemoglobin and the transport and receptor proteins in cell membranes (cholesterolaemias), or blood coagulation factors. - GenomeSum total of the genetic material (cf. gene) in a cell or organism.
- GenomicsStudy of the structure and the function of the genome and all genes.
- GestagensGroup of hormones which have some properties like progesterone. Nearly all the biological actions of gestagens are related to the actions of oestrogens and then depend on both the ostrogen/gestagen ratio and the time sequence of the interactions.
Biological actions
Significance of the gestagens in the regulation of the menstrual cycle and pregnancy: development and regression of the mucous membrane of the womb, maintenance of pregnancy, influence on the ability of the sperm to penetrate into the egg cell, transport of the egg, influence on the environment of the mucous membrane in the oviduct and womb. Every gestagen possesses additional activities, such as oestrogenic or anti-ostrogenic activities.
Clinical Uses
Predominantly in contraception, the so-called hormonal contraception , alone or in combination with oestrogens. Also in combination with oestrogens in hormone replacement therapy after the onset of the menopause, in particular to prevent osteoporosis. Also for disturbances in the menstrual cycle. - Gestational diabetesDiabetes mellitus which first occurs during pregnancy. Occurs in about 1-2% of all pregnancies. There is increased risk for women with overweight or with frequent diabetes mellitus in the family. Gestational diabetes requires insulin (no oral antidiabetic drugs. Cf. embryofetopathia diabetica.
- Glandula thyroideasee thyroid gland
- Glass bone diseasesee osteogenesis imperfecta
- GlaucomaCollective term for various diseases of the eye in which the site of entry of the optical nerve into the retina is expanded and there is usually an increase in intraocular pressure. Glaucoma is one of the most frequent causes of blindness in industrial countries.
Forms
1. Primary glaucoma with open chamber angle: This chronic disease mostly occurs at an advanced age and, if untreated, gradually leads to loss of the function of the eye. 2. Primary glaucoma with closed chamber angle: This mostly occurs as an acute attack with a massive increase in intraocular pressure. Symptoms: In the early stages fog and rainbow colours are seen and there is intense headache, with nausea or even vomiting. The eyeball feels as hard as stone. The conjunctiva is often inflamed, the cornea is swollen and the pupil does not react to light. 3. Secondary glaucoma: Increase in intraocular pressure as a result of another disease. Cause: Regeneration of abnormal blood vessels as a result of inadequate perfusion, for instance in type 2 diabetes or type 1 diabetes, occlusion of the central arteries or veins, injury to the chamber angle tissue as the result of force, occlusion of the runoff paths by metabolic products (e.g. during long term treatment with cortisone) or by pigments (pigment glaucoma) or inflammation or tumours in the eye. 4. In-born glaucoma - Glaucomasee glaucoma
- GlinidesThese are oral antidiabetic drugs which increase the release of the hormone insulin into the body after glucose intake and thus lower concentrations of blood sugar. Glinides bind to the B-cells of the islets of Langerhans in the pancreas, which causes the bubbles which contain insulin (vesicles) to empty. Glinides are used in type 2 diabetes.
- Glitazonessee Thiazolidindiones
- globulinsa diverse group of plasma proteins; alpha- and beta-globulins serve as carriers for certain substances in the blood; gamma-globulins constitute the antibodies of the immune system
- glomerular filtration rate (GFR)the quantity of filtrate produced by the glomerular capillaries in nephrons of both kidneys each minute; GFR is an important index of kidney function; normal values for GFR for adults are 100 ml/min for women and 120 ml/min for men
- GlucagonHormone which is formed in the A-cells of the islets of Langerhans in the pancreas and which counteracts insulin. The main factors increasing glucagon's release are low levels of blood sugar (hypoglycaemia), raised blood concentrations of certain aminoacids, the hormone gastrin (which stimulates acid production in the stomach), adrenalin and TRH (which regulates the thyroid hormones). Glucagons release is inhibited by the hormone somatostatin and by increases in blood sugar concentration.
Actions
Glucagon increases blood sugar concentrations by increasing the breakdown of starch in the liver (glycogenolysis), by increasing the regeneration of glucose (gluconeogenesis) and reducing glucose oxidation. It increases the breakdown of fat (lipolysis) by activating enzymes and increases protein breakdown. Glucagon also raises the heart rate. - Glucocorticoidsalso known as glucosteroids
These are either formed in the adrenal cortex or produced artificially as drugs. The formation and release are stimulated by a hormone (ACTH) from the pituitary (hypophysis). Glucocorticoids are also called stress hormones, as stress factors cause a rapid increase in ACTH and consequently of glucocorticoids. The most important glucocorticoids are cortisol (hydrocortisone), cortisone and corticosterone.
Mechanism of action
Glucocorticoids act through cellular receptors, although there are probably also receptor-independent mechanisms. In this way they stimulate sugar regeneration (gluconeogenesis), fat breakdown (lipolysis) and increase blood concentrations of glucose, aminoacids, free fatty acids and urea. - GluconeogenesisNew formation of glucose in the liver (90 %) and kidneys from non-carbohydrate precursors. Non-carbohydrates include, for example, aminoacids, protein building blocks, which mostly come from the break down of muscle proteins. Other non-carbohydrates which can be used to form glucose are lactate, from red blood cells (erythrocytes) and muscular metabolism and glycerol, a product of the hydrolysis of fats (lipolysis). Gluconeogenesis is formally the reversal of glycolysis.
- Glucosealso known as grape sugar, dextrose and D-glucopyranose
Glucose is the most important sugar in (monosaccharide) in animal and plant carbohydrate metabolism and can be used directly to produce metabolic energy (see glycolysis). It occurs in sweet fruits, sap, honey, animal tissue and blood (blood sugar). Glucose is a component of oligo- and polysaccharides (e.g. starch, glycogen, cellulose), of disaccharides (e.g. saccharose, maltose) and of many other biomolecules. Glucose may be used therapeutically, for example, as an intravenous infusion to ensure nutrition from outside the digestive tract, for the therapy and prevention of dehydration by water loss and the treatment of hypoglycaemic shock.
- Glucose determinationsee methods to determine blood sugar
- Glucose thresholdThe glucose threshold is the blood sugar concentration above which there is increased elimination of glucose in the urine (glucosuria). The glucose threshold depends on age. The average for the healthy population is 180 mg/dl blood (10 mmol/l). Cf. renal threshold
- Glucose toleranceGlucose tolerance is the ability of the body to take up glucose without giving pathologically high blood sugar concentrations (hyperglycaemia) or eliminating sugar through the kidneys (glucosuria)
- Glucose tolerance factorAbbreviation GTF
Biologically active organic complex which stimulates cellular insulin receptors and thus increases cellular uptake of glucose. GTF deficiency is believed to lead to reduced glucose tolerance. The lower the glucose tolerance, the more probable are pathological blood and urine sugar values. Yeast is particularly rich in GTF. - Glucose tolerance testAbbreviation GTT
Procedure for the early recognition of transitional stages between normal carbohydrate metabolism and type 2 diabetes or type 1 diabetes. Glucose tolerance is the ability of the body to take up glucose, without this leading to pathologically raised blood sugar levels (hyperglycaemia) or to elimination of sugar in the kidneys (glucosuria). Abnormal glucose tolerance can be detected with the glucose tolerance test.
Principle
After three days of carbohydrate-rich nutrition (ca. 200 g carbohydrate/day), the subject is made to drink a glucose solution containing 75 or 100 g glucose on an empty stomach. Sugar concentrations in blood and urine are then measured after 1, 2 and (perhaps) 3 hours. The values measured permit a distinction between normal subjects, those with abnormal glucose tolerance and those with diabetes of types 1 or 2. For normal subjects the blood sugar concentration on an empty stomach is under 110 mg/dl and under 140 mg/dl two hours after glucose intake. With type 1 or 2 diabetes the blood sugar concentration on an empty stomach is ca. 126 mg/dl and ca. 200 mg/dl two hours after glucose intake. - Glucose-fatty acid cyclesee Randle cycle
- Glucose-insulin tolerance testsee insulin-glucose tolerance test
- GlucosuriaIncreased urinary elimination of glucose. Glucosuria can be detected by methods to determine blood sugar. The normal value is ca. 70 mg in 24 hours.
Occurrence
In type 2 diabetes, type 1 diabetes and after high-carbohydrate meals when the glucose threshold has been exceeded; also when there is functional kidney damage or after certain drugs. - glucosuriaan abnormally high amount of sugar in the urine; also called glycosuria
- Glycerolalso known as glycerin
Glycerol is a trivalent alcohol which combines with fatty acids to form triglycerides. It is a viscous, colourless sweet tasting liquid which is a side-product of alcoholic fermentation. Glycerol stimulates the mobility of the rectum and stimulates defaecation in this way. It is used therapeutically in constipation as a laxative. - GlycogenGlycogen is a carbohydrate. The so-called animal starch (cf. plant starch) is a highly branched water soluble large molecule (macromolecule) made up of glucose subunits. It is the short term storage form of glucose when there is more glucose than necessary in the body. Ca. 150 g of glycogen are stored in the liver and ca. 300 g in the muscles. The main role of liver glycogen is to regulate blood sugar concentration; muscle glyogen is an energy reserve. Glycogen is broken down by glycogenolysis.
- GlycogenolysisBreakdown of glycogen (short term storage form of glucose) in the cell. It is stimulated by the hormones adrenaline (in liver and muscle) and glucagon (in the liver). A series of biochemical processes leads to glucose, which is released into the blood and is directly available for metabolism.
- GlycohaemoglobinsCertain derivatives of haemoglobin (the red blood dye), haemoglobin-HbA1 derivatives, to which glucose is bound. These are formed in red blood cells (erythrocytes), The diagnostic determination of the glycohaemoglobin HbA1c gives information about the blood sugar concentration. The proportion of HbA1c in total haemoglobin is 4-6% in healthy subjects. In patients with type 2 diabetes or type 1 diabetes, HbA1c can rise proportionally to blood sugar, to up to 12% within 6-8 weeks. The determination of HbA1c serves as quality control for the regulation of blood sugar, the so-called blood sugar memory. The aim of antidiabetic therapy is an HbA1c value of under 6.5%. Cf. haemoglobin.
- GlycolysisBreakdown of glucose to pyruvate in cell plasma. The function of glycolysis is to produce energy from glucose in the form of the energy-rich compound ATP (abbreviation for adenosine triphosphate). If enough oxygen is available, pyruvate is formed during glycolysis. Through further intermediate steps this is introduced into the citrate cycle, some of the products of which are used to give further energy in the respiratory chain. When the levels of oxygen are low, lactate is formed. This leads to the regeneration of coenzymes required for glycolysis, so that glycolysis can continue. The resulting lactate is transported through the circulation to the liver, where it is introduced to the Cori cycle or can participate in gluconeogenesis. The resulting glucose can then be used to form glycogen. Lactate formation occurs in cells and tissues, such as skeletal muscle, cartilage and the mucous membrane of the small intestine, which require energy in spite of short term low levels of oxygen. If there is adequate oxygen much more energy can be produced from pyruvate with the citrate cycle and the respiratory chain than through lactate, so that lactate is generally not formed.
- glycosylationthe addition of sugar molecules to a polypeptide or protein, which alters its shape and improves stability
- GoutGout
Purines are components of DNA. Gout is a disturbance in purine metabolism and may either occur as acute episodes or have a chronic course. It leads to increased blood concentrations of uric acid, which is the final product in purine metabolism, and to deposition of uric acid crystals in various parts of the body, particularly the joints.
Forms
1. Primary gout; in-born metabolic disease. 95% of patients are men. Triggering factors include foods which are rich in purines and aminoacids, such as meat, alcohol consumption and undercooling. 2. Secondary gout; This can occur during diseases of blood formation, when cell breakdown is increased, or when there are disturbances in kidney function, when the elimination of uric acid is decreased.
Symptoms
An acute attack of gout often starts at night, with intense pain, mostly in the joint at the base of the big toe. This becomes very red, is often swollen and doughy, is hot and is very sensitive to pressure. These symptoms are accompanied by shivering and moderate fever (38.5 to 39 0C). In the following nights there are frequently renewed episodes and several different joints can be afflicted in sequence. An asymptomatic phase may then follow, during which the concentrations of uric acid remain high. In more than half of cases however there are further episodes within the following ten years.
Complications
Formation of kidney stones, high blood pressure, painful inflammation of the iris. Other secondary disease can also develop, including abnormalities in lipid metabolism, diabetes mellitus, overweight and liver damage.
Diagnosis
The symptoms are typical. Biochemical proof is provided by the determination of blood uric acid, particularly during an episode. This is followed by punctation of the joint and X-rays.
Therapy
Anti-inflammatory drugs are used during an episode. Further measures are rest, moist and cold compresses and foot baths. There are specific drugs available to lower uric acid concentrations in the long term. There are also several medicines from plants. - GradingComes from the English to grade. Classification of malignant tumours according to their degree of malignancy. Four stages are distinguished (G1-G4). The higher the grade, the higher is the malignity. The grade GX is awarded if the degree of malignity cannot be established.
- Granuloma, EosinophilicA clinical form of a blood disease which is localised in the bone and in which specific types of white blood cells (histiocytes and eosinophilic granulocytes) destroy the bone. The bone disease centres are mostly in the skull, in the femur near the pelvis, in the pelvis or in the spinal column. The disease occurs mostly in children and is often accompanied by pain at night, sometimes with swelling and fever. In some cases, the affected bones may break.
Diagnosis: The diagnosis is made on the basis of typical changes in the X-rays.
Therapy: The treatment is operative removal of the disease centres, sometimes with chemotherapy or radiotherapy.
Prognosis: The chances of a cure lie at above 90%. Relapses, dispersion of the tumour and involvement of other organs are all rare. - Grape sugarsee glucose
- Growth hormonesee STH
- Guillan-Barré SyndromeInflammation of the nerves which leads to flabby paralysis and from which the patient usually recovers.
Causes: The causes are not known with certainty. The condition is probably related to an infection with viruses (cytomegaly, varicella zoster (shingles), measles, mumps, HIV, hepatitis viruses) or with bacteria (Campylobacter, Salmonella, Brucella, Shigella, Spirochetes) or to disturbances in the immune system.
Two forms are distinguished:
Acute Guillan-Barré syndrome: A sudden attack of flabby paralysis with disturbances to the senses in the legs. Can also extend to the arms. Peaks after 2 to 4 weeks.
Chronic Guillan-Barré syndrome: Slower clinical course of the paralysis. May occur in phases, with increases and decreases in the paralysis.
Diagnosis: Examination of the fluid from the spinal chord (liquor). Measurement of the rate of transmission of impulses in the nerves, investigation of samples of nerve tissue
Complications: If certain nerves are attacked, respiratory paralysis or cardiac arrhythmia may develop. Blood clots (thromboses) may develop in paralysed legs. These may come free and lead to obstruction of blood vessels in the lung (pulmonary emboli). If the disease lasts for a protracted period, the size of the muscles may decrease.
Prognosis: The disease mostly clears up spontaneously. There are no consequences, if possible complications are treated.
Glossary entries: Roche and Walter de Gruyter, Berlin