Many of the scientific terms found in the abstracts, articles and lay translations presented on our site are included in this section. We are continually adding terminology found in both new and existing documents.
| K and K | kilobase pairs |
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As K - Symbol for kelvin , lysine , and potassium .
As K - Symbol for equilibrium constant (subscripts may be used to denote the method of measurement, e.g., Kc, Kp).
Indicating one or more groups of two units each of a nucleic acid sequence, each unit being 1000 nucleotides long.
As K - Symbol for kelvin , lysine , and potassium .
As K - Symbol for equilibrium constant (subscripts may be used to denote the method of measurement, e.g., Kc, Kp).
The SI unit of thermodynamic temperature equal to 1/273.15 of the absolute temperature of the triple point of water. Abbreviated K.
Kidney collecting duct cells are cells which are mainly located in the medulla of the kidney. In the kidney, the blood fluid is filtered into tubules (nephrons) where electrolytes, water, and many other components are reabsorbed or even secreted. Collecting duct cells are at the end of such nephrons. Here, water is reabsorbed from the urine, and therefore, urine becomes concentrated. Reabsorption of water in collecting duct cells is regulated by the V2 vasopressin receptor. Inactivating mutations of V2 vasopressin receptor result in a loss of water reabsorption in collecting duct cells—the cause of nephrogenic diabetes insipidus (Schöneberg).
1. Killer cells; cells mediating antibody-dependent cell-mediated cytotoxicity (ADCC). They are small lymphocytes without T or B cell surface markers. K cells recognize IgG antibody coating the target cell by means of Fc receptors. Lysis of the target cell is extracellular, requires direct cell-to-cell contact, and does not involve complement.
2. Cells located predominantly in the midzone of the duodenal and jejunal mucosa that synthesize gastric inhibitory polypeptide.
An absolute temperature scale whose unit of measurement, the kelvin, is equivalent to the degree Celsius, the ice point therefore being at 273.15 kelvins.
Renal cortex (cortex renalis). The outer part of the substance of the kidney, composed mainly of glomeruli and convoluted tubules.
The excretion of potassium in the urine.
Any of a family of scleroproteins that form the primary constituents of epidermis, hair, nails, and horny tissues. Included are the cytokeratins of epithelial tissue and the hard keratins of ectodermally derived structures such as hair and nails. Because it is insoluble in gastric juice, keratin is sometimes used to coat pills designed to dissolve in the intestine.
Any deviation from or interruption of the normal structure or function of the kidney, manifested by characteristic symptoms and signs (e.g., polycystic kidney disease); the etiology, pathology, and prognosis may be known or unknown.
1. Pertaining to, characterized by, or promoting kaliuresis.
2. An agent that promotes kaliuresis.
Intermediate filaments composed of cytokeratins; they are usually heteropolymers formed from one acidic and one basic cytokeratin and are present in most epithelial cells. The cytokeratin composition varies in different types, states, and degrees of differentiation of the epithelia and has been used as an immunohistochemical marker. Keratin filaments form a cytoskeletal framework, anchoring other elements and inserting into sites of cell-to-cell contact and are thus tonofilaments.
The kidneys are susceptible to a wide range of disorders. However, only one normal kidney is needed for good health, so disease is rarely life-threatening unless it affects both kidneys and has reached an advanced stage.
Hypertension (high blood pressure) can be both a cause and effect of kidney damage. Other effects of serious disease or damage include the nephrotic syndrome (in which large amounts of protein are lost in the urine and fluid collects in body tissues) and acute or chronic renal failure.
Congenital and Genetic Disorders
Congenital abnormalities of the kidneys are fairly common. In horseshoe kidney, the two kidneys are joined at their base. Some people are born with one kidney missing, both kidneys on one side, or a kidney that is partially duplicated and gives rise to two ureters (duplex kidney). These conditions seldom cause problems. In rare cases, a baby is born with kidneys that are so underdeveloped that they are barely functional.
Polycystic disease of the kidneys is a serious inherited disorder in which multiple cysts develop on both kidneys. In Fanconi's syndrome and renal tubular acidosis (which are rare), there are subtle abnormalities in the functioning of the kidney tubules, so that certain substances are inappropriately lost in the urine.
Impaired Blood Supply
Various diseases may cause damage to, or lead to obstruction of, the small blood vessels within the kidneys, impairing blood flow. Diabetes mellitus and hemolytic-uremic syndrome are examples. In physiological shock, blood pressure and flow through the kidneys are seriously reduced; this can cause a type of damage known as acute tubular necrosis. The larger blood vessels in the kidney may be affected by periarteritis nodosa and systemic lupus erythematosus. In rare cases, there is a defect of the renal artery supplying a kidney, which may lead to hypertension and tissue damage.
Autoimmune Disorders
Glomerulonephritis refers to an important group of autoimmune disorders in which the glomerular filtering units of the kidneys become inflamed. It sometimes develops after infection with streptococcal bacteria.
Tumors
Benign kidney tumors are rare. They may cause hematuria (blood in the urine), although most cause no symptoms. Malignant tumors are also rare. Renal cell carcinoma, the most common type, occurs mostly in adults over 40; nephroblastoma (Wilms' tumor) affects mainly children under 4. (See also kidney cancer.)
Metabolic Disorders
Kidney stones are common in middle age. They are usually caused by excessive concentrations of various substances (such as calcium) or lack of inhibitors of crystallization in the urine. In hyperuricemia, there is a tendency for uric acid stones to form. (See also calculi.)
Infection
Infection of a kidney is called pyelonephritis. An important predisposing factor is obstruction of the flow of urine through the urinary tract, leading to stagnation and subsequent infection spreading up from the bladder. The cause of the obstruction may be a congenital defect of the kidney or ureter, a kidney or ureteral stone, a bladder tumor, or, in a man, enlargement of the prostate gland.
Tuberculosis of the kidney is caused by infection carried by the blood from elsewhere in the body, usually the lungs.
Drugs
Allergic reactions to certain drugs can cause an acute kidney disease, with most of the damage affecting the kidney tubules. Other drugs may directly damage the kidneys if taken in large amounts for prolonged periods. For example, renal failure can develop after many years of taking excessive amounts of analgesics. Some potent antibiotics can damage the kidney tubules, producing acute tubular necrosis.
Other Disorders
Hydronephrosis refers to a kidney swollen with urine as a result of obstruction further down the urinary tract. In the crush syndrome, kidney function is disrupted by proteins (released into the blood from severely damaged muscles) that block the filtering mechanisms.
See also nephrogenic diabetes insipidus.
Investigation
Kidney disorders are investigated by kidney imaging techniques such as ultrasound scanning, intravenous or retrograde pyelography, angiography, and CT scanning; by renal biopsy (removal of a small amount of tissue for analysis); by blood tests; and by kidney function tests, such as urinalysis.
Any of several serine proteinases that cleave kininogens to form kinins (bradykinin, kallidin).
To make, or become, keratinous.
Renal failure.
Kinin system.
The epidermal cell which synthesizes keratin; constituting 95 percent of the epidermal cells and, with the melanocyte, forming the binary cell system of the epidermis. In its various successive stages it is known as basal cell, prickle cell, and granular cell. Called also "malpighian cell."
Tests performed to investigate urinary symptoms and kidney disorders. Kidney function tests may also be performed as part of a routine investigation before major surgery, or before prescribing drugs that are eliminated by the kidney. The tests are also performed to determine the function of a transplanted kidney.
Types
Urinalysis is a simple kidney function test. Collected urine is examined under the microscope for blood cells, pus cells, and casts (cells and mucuslike material that accumulate within the tubules and pass into the urine). Urine may also be cultured to confirm the presence of infection. It also may be tested for substances that are present only when the kidneys are diseased or damaged.
Kidney function can be assessed by measuring the concentration of substances in the blood (such as urea and creatinine) normally eliminated from the body via healthy kidneys. The creatinine clearance test provides an assessment of kidney function by comparing the amount of creatinine in the blood with the amount excreted in the urine over a timed interval, usually 24 hours.
Kidney function may also be assessed by kidney imaging techniques, which can help identify whether one or both kidneys are diseased.
1. The tenth letter of the Greek alphabet.
2. A statistic calculated to quantify the extent to which agreement between observers exceeds that expected on the basis of chance alone.
See also kappa light chains .
Containing or of the nature of keratin.
The inner part of the substance of the kidney, composed chiefly of collecting tubule elements, loops of Henle, and vasa recta, organized grossly into pyramids.
A type of light polypeptide chain found in immunoglobulin molecules. See light chain .
Acidosis accompanied by the accumulation of ketone bodies (ketosis) in the body tissues and fluids, as in diabetic acidosis and starvation acidosis.
See "renal medulla."
A type of light polypeptide chain of immunoglobulin molecules. See light chain.
Any ketose containing six carbon atoms, such as fructose.
Renal calculus.
The nucleoplasm, or protoplasm of the nucleus of a cell.
The substances ß-hydroxybutyric acid, acetoacetic acid, and acetone, which are produced by fatty acid and carbohydrate metabolism in the liver in approximately a 78:20:2 ratio. Acetoacetate is produced from acetyl-CoA; most is enzymatically converted to ß-ketobutyrate, but a small amount is spontaneously decarboxylated to acetone. The ketone bodies can be used as fuels by muscle and brain tissue. In starvation and uncontrolled diabetes mellitus, large quantities are produced causing metabolic acidosis and elevated blood and urine levels of all three ketone bodies.
See renal tubules .
Any of the condensed irregular clumps of chromatin dispersed in the chromatin network of a cell.
Abnormally elevated concentration of ketone bodies in the body tissues and fluids when fatty acids are incompletely metabolized, a complication of diabetes mellitus, starvation, and alcoholism.
A pair of vertebrate organs situated in the body cavity near the spinal column that excrete waste products of metabolism, in man are bean-shaped organs about 4-1/2 inches long lying behind the peritoneum in a mass of fatty tissue, and consist chiefly of nephrons by which urine is secreted, collected, and discharged into a main cavity whence it is conveyed by the ureter to the bladder.
As "kb" - In genetics, kilobase (1000 bases); sometimes used incorrectly to denote kilobase pairs in double-stranded nucleic acid.
As Kb - Symbol for base dissociation constant .
Kilogram.
1. K cells.
2. Cytotoxic T lymphocytes.
Also kD. Abbreviation for kilodalton .
One of a pair of vertebrate organs situated in the body cavity near the spinal column that excrete waste products of metabolism, in man are bean-shaped organs about 4-1/2 inches long lying behind the peritoneum in a mass of fatty tissue, and consist chiefly of nephrons by which urine is secreted, collected, and discharged into a main cavity whence it is conveyed by the ureter to the bladder.
Cytotoxic T lymphocytes.
Also kD. Kilodalton.
Cancers that have their origins in the kidneys themselves are not rare. Cancer that starts in other organs rarely spreads to the kidneys.
TYPES
There are three main types of cancer arising in the kidneys.
Renal Cell Carcinoma This is the most common type of kidney cancer, accounting for about 75 percent of all kidney growths. The tumor usually occurs after the age of 40 and affects twice as many men as women. The most common symptom is hematuria (blood in the urine). There may be pain in the loins, a lump in the abdomen, fever, or weight loss. About 25 percent of patients survive five years or more because the tumor often has spread to the lungs, bone, liver, and brain by the time treatment is started.
Nephroblastoma Also called Wilms' tumor, this cancer accounts for about 20 percent of all cancers in children. It is found mainly in children under the age of 4 years and occurs almost twice as often in males. Nephroblastoma grows rapidly and is often felt as a lump in the abdomen. This cancer occasionally causes abdominal pain. Nephroblastoma frequently spreads to the lungs, liver, and brain. If treatment is started early, about 50 to 80 percent of children survive.
Transitional Cell Carcinoma This type arises from cells lining the renal pelvis. It develops in tobacco smokers and in people who have consumed very large quantities of analgesics (painkillers) over the course of many years. Hematuria is a common symptom; hydronephrosis (distention of the kidney with urine) may occur due to blockage of the ureter. Survival rates vary greatly, depending in part on early detection and treatment of the tumor.
DIAGNOSIS AND TREATMENT
Diagnosis is made by intravenous pyelography or by renal angiography. Treatment consists of nephrectomy (removal of the kidney) and sometimes removal of the ureter as well. In the case of a nephroblastoma, nephrectomy is followed by radiation therapy and chemotherapy.
A unit used in designating the length of a nucleic acid sequence; e.g., 7 kb indicates a sequence 7000 nucleotides long. Abbreviated kb.
1. Sharp.
2. Severe.
3. Enthusiastic.
4. Mentally alert.
5. Strong, acute.
6. Wonderful, excellent.
7. A lamentation for the dead uttered in a loud wailing voice or in a wordless cry.
Also known as the tubulus renalis colligens , or renal collecting tubule: that structure of the kidney consisting of the arcuate renal tubule, straight collecting tubule, and papillary duct considered together.
Indicating one or more groups of two units each of a nucleic acid sequence, each unit being 1000 nucleotides long.