Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

14 results found
Article

Alpha fetoprotein

Alpha fetoprotein (AFP) is an important plasma protein synthesized by the yolk sac and fetal liver. In adults its main utility is as a tumor marker, primarily for hepatocellular carcinoma or teratoma. Functionally it is the fetal homologue of albumin, i.e. it acts as a major carrier protein in t...
Article

Hepatoblastoma histological classification

Although hepatoblastomas can be histologically classified into a variety of sub types, it is important to remember that with the possible exception of small cell undifferentiated sub type, prognosis is independent of histology when adjusted for stage gender and age 1. major categories epitheli...
Article

Mammalian target of rapamycin

The mammalian target of rapamycin (mTOR), also known as mechanistic target of rapamycin, are two proteins that are involved in cell signaling pathways implicated in tumorigenesis. The mTOR proteins are serine/threonine protein kinases that combine with several other proteins to form two large c...
Article

Oxygen

Oxygen (chemical symbol O) is one of the basic organic elements, and is a constituent of most of the known organic molecules - and therefore all lifeforms - on earth.  Chemistry Basic chemistry Oxygen is a colourless odorless diatomic gas with an atomic number 8 and atomic weight 15.999. It h...
Article

Primary lung tumors in children

Pediatric primary lung tumors are rare in children however they must be distinguished from locally aggressive inflammatory conditions and benign disease. 1 Primary lung tumors in the neonates and infants include: pleuropulmonary blastoma (PPB) infantile fibrosarcoma of the lung fetal lung in...
Article

PSA density

The PSA density (PSAD), is a calculation performed at diagnosis and is the serum PSA level (ng/mL) divided by the volume of the prostate gland (mL)1. Prostate volume is calculated from TRUS measurements2,3.  Alternatively, PSAD may be calculated using MRI measurements3 of prostate volumes or le...
Article

Pseudocyst

A pseudocyst is an abnormal fluid-filled cavity which is not lined by epithelium.  It is this fact that distinguishes it pathologically from a cyst, which is lined by epithelium. Examples of pseudocysts are: pancreatic pseudocyst pulmonary pseudocyst pseudocysts of the germinal matrix
Article

Vitamin A

Vitamin A are a group of fat-soluble vitamers (the retinoids) required for many physiological functions, mainly vision, reproduction and epithelial maintenance. In the retina, a specific retinoid, 11-cis-retinal, is formed by photoisomerisation within the rods and cones. Related pathology Path...
Article

Vitamin B1

Vitamin B1 (thiamine) is a water-soluble vitamin, that is part of the vitamin B complex, and is an important coenzyme for two reactions in the citric acid cycle (Kreb cycle). It therefore is vital for cellular ATP production, particularly in the central nervous system. Terminology Thiamine is ...
Article

Vitamin C

Vitamin C (ascorbic acid) is a water soluble vitamin that is a coenzyme for the formation of the structure protein collagen, particularly creating cross-linking of collagen fibers which greatly increases its tensile strength. It also acts as an antioxidant. History and etymology Vitamin C was ...
Article

Vitamin D

Vitamin D (calciferol) is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D exists in two main forms (vitamers) in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).  Vitamin D3 acts by re...
Article

Vitamin D deficiency (overview)

Vitamin D deficiency (also known as hypovitaminosis D) is common, and untreated, may result in serious sequelae. Traditionally its pathological manifestations have been regarded through the lens of skeletal maturity: rickets in children osteomalacia in adults However it has become increasingl...
Article

Vitamin E

Vitamin E (the tocopherols) are a group of fat-soluble vitamins that act as antioxidants. hypovitaminosis E is rarely seen outside premature infants hypervitaminosis E is extremely rare as the toxicity of vitamin E is low except in chronic (usually >1 year) high doses. The commonest sequela is...
Article

Vitamin K

Vitamin K is not a single compound but a family of fat-soluble vitamins essential for normal blood-clotting function and comprises two vitamers that are found naturally: phytomenadione (also known as phylloquinone or K1) and menaquinone (or K2). Menaquinone (K2) is synthesized by normal flora i...

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