Terminology

Terminology

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Acute interstitial nephritis
(AIN)
A kidney disease characterized by acute onset, a decreased renal function and microscopic changes mainly located to the renal interstitium (edema and/or infiltration of white blood cells).
Acute tubular nephritis
(ATN)
A kidney disease characterized by acute onset, a decreased renal function and microscopic changes mainly located to the renal tubules.
Acute tubulo-interstitial nephritis (ATIN) A kidney disease characterized by acute onset, a decreased renal function and microscopic changes located to the tubules and the renal interstitium
Albumin The dominating protein in the plasma. The normal level of albumin in the plasma of healthy individuals is about 4 gram per liter.
Antigen A substance, foreign to the body, that stimulates the immune system to produce antibody or to elicit a response from white blood cells. The resulting antibodies and the reacting cells are specific for the stimulating antigen
Antibody A plasma protein (immunoglobulin) that has the ability to combine with the antigen that caused its production (see above)
Atrioventricular shunt A device for drainage of the cerebral ventricular fluid (“water on the brain”) inoperated between the ventricles of the brain and the right atrium of the heart.
Auto-immune disease A condition where the immune system reacts against the body’s own constituents
Casts Cylindric formations in the urine produced by protein that has coagulated inside the renal tubules. Casts may contain various blood cells or tubular epithelial cells.
Complement A complex system of more than 30 various enzymes in serum and on the surface of cells. They are activated for instance by contact with immune complexes and microorganisms. Being activated they will start various types of  inflammatory reactions in the tissue and thus contribute to an elimination of  microorganisms or damaged cells.
Electron microscope With a (transmission) electron microscope it is possible to reveal the ultrastructure of the interior of cells. An electron microscope may enlarge by almost 500,000 times.
Eosinophilia An increased number of a certain type of white blood cells, the eosinophilic leucocytes. An abnormally high number of eosinophils is a common finding in patients with an allergic disease.
Focal, segmental glomerulonephritis Glomerulonephritis localized to a few glomeruli only (focal) and in these glomeruli only to segments of the glomerulus (segmental). One of the many unanswered questions about glomerulonephritis is how an immunological disease can be focal and segmental. The phenomenon is easily explained by the toxic-allergic hypothesis (Ravnskov 1988).
Glomerular basement membrane (GBM) The membrane that separate the capillary walls in the glomerulus from the urinary space. The primary urine is produced by blood filtered through the GBM
Glomerulus
(plural: glomeruli)
A glomerulus is composed of 5-6 capillary loops that spring from the afferent arteriole (the arteriole that leds to the glomeruli) and end in the efferent arteriole (the arteriole that leads away from the glomerulus), surrounded by Bowman’s capsule. The wall of a glomerular capillary is composed of three layers, the endothelial cells that line the inside of the capillary wall, the glomerular basement membrane, and the glomerular epithelial cells (also named podocytes) that are continuous with the cells lining the inside of Bowman’s capsule which again are continuous with the tubular cells. Each kidney has about 1 million glomeruli.
Goodpasture’s syndrome A rare disease characterized by anti-GBM nephritis and bleedings from the lungs
Haematuria Blood in the urine
Hydrocarbon A chemical compund the core of which is composed by carbon and hydrogen atoms. In an aliphatic hydrocarbon the carbon atoms are put together  as a chain; in an aromatic hydrocarbon they are put together as a ring or as several rings (polyaromatic hydrocarbons). The most important sources of hydrocarbon exposure are mineral oil, petroleum distillates and combustion fumes. Most fuels and solvents are produced by distillation of mineral oil at different temperatures. As it is extremely difficult to isolate a pure hydrocarbon by distillation all hydrocarbon products are composed of hundreds or thousands of different hydrocarbon molecules.
Immune complex The union of antigen , antibody and complement
Immunofluorescence microscopy A technique used to localize specific constituents in tissue sections. Specific antibodies against the constituent in question are tagged with fluorescent chemicals. In the microscope it is thus possible to recognize the localization in the tissue of any constituent provided a specific antibody is available. In glomerulonephritis the technique is primarily used to identify various immunoglobulins and complement components in the glomeruli.
Immunoglobulin A group of plasma proteins, produced by the immune system and functioning as antibodies. There are five types of immunoglobulins, immunoglobulin G (IgG), A (IgA), M (IgM), D (IgD) and E (IgE)
Inflammation An influx into the tissue of blood cells and fluid caused by reactions of the immune system against injury or foreign substances, for instance microorganisms or chemicals.
Interstitium, renal The connective tissue that binds together the glomeruli and the tubules
Lymphokine A substance produced by lymphocytes (a kind of white blood cells) when the lymphocyte is stimulated by an antigen. Lymphokines are released to the blood circulation and they can thus exert their effect far away from the cells that produced it
Membranous glomerulonephritis A subgroup of glomerulonephritis characterized by granular deposits of immunoglobulins and complement lying on the outside of the glomerular basement membrane beneath the epithelial cells. They have a typical appearance on electron microscopy.  Membranous glomerulonephritis is thought to be caused by auto-immunity, eg. the antibodies áttack some of the body’s own components located in the glomerulus.
Minimal change nephropathy A subgroup of glomerulonephritis characterized by heavy proteinuria but with no or minimal changes seen by light microscopy and no deposits of immunoglobulins or complement factors are seen by immunofluorescence microscopy. Electron microscopy shows fusion of the podocytes. Minimal change nephropathy is the most common type of glomerulonephritis in children and there is much evidence that the increased permeability of the glomerular filter and the resulting  proteinuria and podocyte fusion is caused by lymphokines
Nephrotic syndrome  A combination of heavy proteinuria, low plasma albumin and fluid retention in the body.
Nephrotoxic Toxic to the kidneys
Plasma  The fluid that remains when all cells of the blood (red and white blood cells and platelets) have been eliminated (by centrifugation).
Podocyte Another name for the glomerular epithelial cell, see glomerulus
Primary urine The fluid that is produced after filtration of the blood in the glomeruli. Almost 200 liter primary urine is produced by the glomeruli every 24 hour. After having passed the renal tubules this amount is reduced to 1-3 liter urine
Proteinuria An increased amount of plasma proteins in the urine. Normal urine has less than 25 mg protein per liter. Urine from patients with the nephrotic syndrome has 4 gram protein per liter or more
Systemic Lupus Erythematosus (SLE) A chronic, autoimmune, inflammatory disease, most commonly affecting the skin, the joints (arthritis) and the kidneys (glomerulonephritis), but many other organs may be affected as well.
Serum The fluid that remains when blood has coagulated and the clot has been removed, eg. serum is plasma without fibrinogen.
T-cell A white blood cell produced in the thymus. T-cells have important functions in the body’s defense against microorgaanisms
Tubules Microscopic channels that lead the primary urine through the kidney to the pelvis of the kidney from where it goes down to the urinary bladder. During the passage through the tubules, salt, water and other useful substances are reabsorped from the primary urine and toxic substances are excreted into it. The tubules also maintain the body’s acid-base balance.
Tubulointerstitial tissue The tissue that surrounds the glomeruli, composed of the tubules (normally by far the major part) and the interstitial tissue. In inflammatory states the interstitial tissue is increased and may be dominated by white blood cells and/or edema and/or connective or fibrous tissue, a condition called interstitial nephritis. In case the tubules are abnormal also, it is called tubulointerstitial nephritis.
Wegener Granulomatosus Wegener’s granulomatosis is a rare type of autoimmune inflammation of small arteries and veins (vasculitis). Most often the disease is located to the lungs, the nasal cavities and the kidneys. If the kidneys are engaged the clinical picture is glomerulonephritis.

 

 

 

 

 

 

 

 

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