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.
21 results found
Article
Erythrocyte sedimentation rate
Erythrocyte sedimentation rate (ESR) is a non-specific marker of acute inflammation which is seen in a very wide spectrum of pathologies. It has been sidelined by the use of C-reactive protein and other acute phase markers but it still has an important role to play in the management of some cond...
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
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
Hemoglobin
Hemoglobin (Hb) is the oxygen-carrying molecule in red blood cells.
Structure
Hemoglobin is a tetrameric protein molecule composed of four subunits. Each subunit consists of an iron-containing cyclic heme component linked to a polypeptide chain, the polypeptides are together known as globin. E...
Article
Red blood cells
Red blood cells (RBCs), also known as erythrocytes (or rarely haematids), are cells that carry oxygen by means of hemoglobin, and form part of the cellular component of blood as it circulates throughout the body. These extremely common cells are typically made in the bone marrow in a process cal...
Article
Birbeck granules
Birbeck granules refer to unusual rod-shaped structures specific to Langerhans cells. Their origin and function remain undetermined. Langerin is a crucial component within Birbeck granules.
History and etymology
Birbeck granules were first described by Michael S Birbeck in 1961 3.
Related pat...
Article
CD34
CD34 or hematopoietic progenitor cell antigen CD34 is an intercellular adhesion protein and cell surface glycoprotein and a frequently used marker of hematopoietic progenitor cells and endothelial cells. It is also expressed by many other non-hematopoietic cell types including multipotent mesenc...
Article
Eosinophil
Eosinophils, also less commonly known as acidophils, are myeloid granulocytes and form one of the main types of white blood cells. Their counts are routinely measured as part of a full blood count. They have important roles in fighting parasitic infections, but are increasingly recognized as hav...
Article
Platelets
Platelets, also known as thrombocytes, are an essential constituent of the cellular component of blood. They play a key role in normal hemostasis. Normal platelet levels in adult patients are 150-400 x 109/L.
Physiology
Platelets are tiny (2-4 μm) cells that lack nuclei 1-3. They are mass prod...
Article
Thrombocytosis
Thrombocytosis (plural: thrombocytoses) is a general term and is defined as a rise in platelet count to over two standard deviations above the normal range. Its exact quantitative definition is variable, but generally equates to a platelet count greater than 400-450x109 cells/L.
Although there...
Article
Immunity
The human body regularly encounters harmful micro-organisms, and because of this it has developed a system of defenses to help identify and eliminate infective pathogens in the body, known as immunity, executed by the immune system. This system also contributes to antioncogenic mechanisms.
Type...
Article
Hypersensitivity reaction
Hypersensitivity reactions are the immunological response to both exogenous and endogenous antigens, and form the basis for many diseases.
Pathology
Classification
Using the Gell and Coombs' classification, there are four types of hypersensitivity reactions, each mediated by a different mech...
Article
Anaplastic lymphoma kinase (ALK) gene rearrangements
Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumors. The genes code for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor (also known as CD246) which is thought to play a role in brain development and exerts i...
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...
Article
Blood
Blood is a connective tissue usually found in a liquid phase; it comprises a fluid component called plasma (about 55% of the total volume), in which lies the cellular component, comprising several cell lineages, primarily the white blood cells, red blood cells and platelets. In an average adult ...
Article
White blood cell
White blood cells or leukocytes are one of the main cell types found in normal human blood. They are actually colourless (but appear white on light microscopy) and are divided into granular and non-granular types.
Types of white blood cell:
granular
neutrophils
eosinophils
basophils
non-gr...
Article
Iron
Iron (chemical symbol Fe) is one of the trace elements that is essential for normal human health due to its central importance in the structure and function of hemoglobin and the cytochromes.
Chemistry
Basic chemistry
Iron is a transition metal with atomic number 26 and an atomic weight of 55...
Article
Lactate dehydrogenase
Lactate dehydrogenase (LDH or LD) is a key enzyme in most cells, catalyzing the reversible conversion of pyruvate to L-lactate. Its contemporaneous main clinical uses are limited primarily to the investigation of hemolysis, serous collections and as a tumor marker.
Physiology
L-lactate dehydro...
Article
Hematinics
The hematinics are nutrients that are required by the body for erythropoiesis, i.e. the production of red blood cells 1,2.
List of hematinics
Clinically, the most important hematinics are vitamin B12, iron and folic acid because deficiency states of these three substances are much more common ...
Article
Extranodal extension
Extranodal extension refers to the growth of a nodal cancer metastasis beyond the confines of the capsule of a lymph node into adjacent tissues. Less preferred synonyms include extranodal spread, extracapsular extension, or extracapsular spread.
This finding holds prognostic implications. For e...
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