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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
321 results found
Article
RNA
RNA (ribonucleic acid) is one of the two major nucleic acids in biological cells, the other being DNA; unlike DNA, RNA is single-stranded. The composition of the nucleotides and nucleosides is also partly different due to variations in the monosaccharide and base constituents: D-ribose sugar rep...
Article
Alzheimer type II glia
Alzheimer type II glia are a type of glial cell. They are a pathological reactive astrocyte seen in the brain, unrelated to Alzheimer disease. They are seen most frequently in Wilson disease, but also in other systemic metabolic disorders, particularly those with elevated ammonia levels, typical...
Article
EGFR mutation
An epidermal growth factor receptor (EGFR) mutation may be expressed in a large proportion of non-small cell lung carcinomas (NSCLC). However, certain subtypes such as invasive mucinous adenocarcinoma of the lung can have very low expression.
The presence of this mutation can be assessed on bio...
Article
WHO classification of eye tumors
The World Health Organizatiοn (WHO) classification of eye tumors is a widely used pathologic classification system of neoplasms of the orbit. The current revision, part of the 4th edition of the WHO series, was published in 2018 and is reflected in the article below 1.
Classification
Tumors of...
Article
Naming of organisms
Occasionally, we will refer to lifeforms in an article or case, and we adhere to standard scientific convention when it comes to naming of organisms, as set down by the International Commission on Zoological Nomenclature (ICZN) 1. As per the standard binomial system, the genus and species of the...
Article
Feces
Feces, also known as stool, is the solid component of human waste. Almost half of its dry mass is bacterial biomass, with the remainder comprised of undigested dietary matter, exfoliated cells of the gut, intestinal secretions, small metabolites and mucus.
Composition
Fecal matter is semisoli...
Article
Flail mandible
A flail mandible is an uncommon type of comminuted fracture through the mandibular symphysis and bilateral condyle and/or rami which can result in posterior displacement and internal rotation of the mandibular bodies, eversion of the angles of the mandible, and glossoptosis. Together with concom...
Article
Panniculitis
Panniculitis (plural: panniculitides 1) is a non-specific histopathological term referring to inflammation of adipose tissue. It most commonly affects subcutaneous fat, although internal forms, e.g., mesenteric panniculitis, are well-known 1,2.
Clinical presentation
Most panniculitides present...
Article
Peribronchiolar metaplasia
Peribronchiolar metaplasia is a partially recognized pathological entity characterized by fibrosis of the alveolar septa adjacent to terminal bronchioles and alveolar ducts, with bronchiolar-type epithelial metaplasia of the peribronchiolar alveolar walls. It is currently only accepted by some a...
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
Tumor markers
Tumor markers are a group of molecules in serum that are elevated in various malignancies and are often used to monitor treatment response as well as alert for potential progressive disease when in remission.
Commonly used markers include:
AFP (alpha fetoprotein)
beta-hCG
CA 15-3
CA 19-9
C...
Article
Sulfur
Sulfur (chemical symbol S) is one of the essential trace elements. It has an important biological role as part of sulfur-containing amino acids and other important biochemical species such as glutathione, hydrogen sulfide, and coenzyme A.
Terminology
Sulfur has been the preferred spelling of t...
Article
Septum
Septa (singular: septum) are anatomical or pathological sheet-like structures that subdivide a component of normal anatomy or a lesion.
Terminology
Septa is the plural of the Latin word septum. Septae and septi are erroneous forms and are not words in English, nor correct plurals in Latin 2. S...
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 ...
Article
Fomites
Fomites (singular: fomes) are used in medicine to refer to inanimate porous or non-porous objects, or surfaces colonized with microbes (viruses, bacteria, fungi) and serve as vehicles for transmitting many pathogenic microorganisms 1-3. Some examples of fomites are clothing, mobile phones, handr...
Article
Anemia
Anemia is the presence of reduced hemoglobin in the blood. Formally, the World Health Organizatiοn (WHO) defines anemia by the hemoglobin concentration in the blood according to age and sex 1:
adult men: <130 g/L
adult women: <120 g/L
Values for pregnant women and children are different.
Cli...
Article
Ascitic fluid cholesterol level
Ascitic fluid cholesterol level estimation is a simple and precise test for differentiating malignant ascites from non-malignant (cirrhotic) ascites 5-9.
Pathology
Ascites is the abnormal collection of fluid within the peritoneal cavity. Malignant ascites comprises ~10% and is usually seconda...
Article
Eosinophilia
Eosinophilia is defined as an abnormally high level of eosinophils in the blood, this is usually defined as >500 cells/μL (normal eosinophil level: <450 cells/μL). Hypereosinophilia is defined as >1500 cells/μL and is usually due to hematological malignancy 1,2.
This article includes recommenda...
Article
Aspergillus clavatus
Aspergillus clavatus is one of the species of Aspergillus that can cause pathology in humans. It is allergenic and causes a hypersensitivity pneumonitis called malt-workers lung.
See also
Aspergillus
Aspergillus fumigatus
Aspergillus flavus
Aspergillus clavatus
Article
Zinc
Zinc (chemical symbol Zn) is a trace element with a key role as a constituent of enzymes (e.g. carbonic anhydrase), as a part of zinc finger proteins vital for the correct folding of macromolecules (such as DNA), and as an important cellular messenger 3.
Chemistry
Basic chemistry
Zinc is a tr...
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