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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Haemochromatosis - Hairy Root Culture
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Haematemesis
Vomiting of blood.
Haematin
Oxidised haem (Fe3+) released from haemolysed red cells containing methaemoglobin or from free haem during intravascular haemolysis. Haematin combines with albumin in circulation to form methaemalbumin.
Haematoma
Localised collection of clotted blood in a space, tissue or organ.
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Haematopoietic stem cells
Precursor cells in the bone marrow that develop into mature blood cells.
Haematuria
Presence of blood or red blood cells in urine.
Haemochromatosis
A clinical condition characterised by deposition of hawmosiderin that disrupts normal cellular and organ function due to iron-induced parenchymal damage.
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Haemoconcentration
Decrease in the fluid content of blood with resultant increase in the concentration of formed elements.
Haemodialysis
The process of removing blood from an artery to remove waste product through dialysis, and returning the blood into the body through a vein.
Haemodialysis is used to treat end stage renal failure.
Haematopoiesis
The process of blood cell formation. This occurs in the yolk sac and the liver during early foetal development and in the bone marrow in adults.
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Haemodilution
Increase in the fluid content of blood leading to decreased concentration of formed elements.
Haemoglobin
A red pigment found in the erythrocytes of vertebrates. It is a conjugated protein containing four molecules of haem and the protein globin. The haem moiety in haemoglobin is Protoporphyrin IXa, a tetrapyrrole ring system linked to ferrous iron. The globin moiety consists of two pairs of polypeptide chains –two α and two β chains. Each of the polypeptide chains binds one molecules of haem. Haemoglobin plays an important role in the transport role in the transport of gases (oxygen, carbon dioxide) and protons in blood.
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Haemolymph
The fluid present in the body cavity of insects that functions in gas exchange.
Haemolysins
A group of bacterial toxins that cause haemolysis by attacking red blood cell membranes.
Haemolysis
Release of haemoglobin from the red cells into the plasma.
Haemolytic anemia
Anaemia that results from lysis of red blood cells.
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Haemoglobinuria
Presence of haemoglobin in urine. This occurs when there I intravascular haemolysis as in sickle cell anaemia, thalassaemia, haemolytic anaemia, paroxysmal haemoglobinuria dueto cold and stress, and due to chemicals such as sulphonamides or arsenicals. Haemoglobinuria can be detected by spectroscopic examination for haemoglobin. This can be distinguished from haematuria in which red cells are present.
Haemolytic jaundice
Also called prehepatic jaundice. There is excessive breakdown of haemoglobin and overproduction of bilirubin at a rate far exceeding the capacity if the liver for conjugation and excretion. Increased haemolysis occurs in congenital erythrocyte abnormalities such as hereditary haemoglobinopathies, deficiency of glucose -6- phosphate dehydrogenase (G6PD), ineffective erythropoiesis, incompatible blood transfusions, resorption of haematomas, infections by haemolytic organisms such as Plasmodium species and drugs such as sulphonamides and salicylates which displace bilirubin from plasma albumin.
Haemopexin
A β-globulin that binds haem and prevents its excretion in urine. This complex is removed from the circulation by the liver and the iron is reutilized. Haemopexin levels are increased in patients with haemolytic anaemia.
Haemophilia
An inherited disorder characterised by bleeding tendency due to a defect in the blood clotting mechanism. This occurs due to a deficiency of a normal blood protein, factor VIII (antihaemopilic globulin). It may also arise due to a deficiency of factor IX (Christmas disease, haemophilia B).
Haemopoiesis
The formation of blood cells in the bone marrow.
Haemorrhage
Bleeding.
Haemorrhagic stroke
Stroke that occurs when a blood vessel ruptures and bleeds into the brain.
Haemosiderin
A storage form of iron found mainly in the reticuloendothelial system.
Haemosiderosis
An increase in iron stores as haemosiderin that can be identified by histopathology. When haemosiderin deposits disrupt normal cellular and organ function due to iron-induced parenchymal damage, a clinical condition known as haemochromatosis develops.
Hair
A single or multicellular, absorptive (root hair), secretory (glandular hair) or a superficial outgrowth (covering hair) of he epidermal cells. The term trichome includes outgrowths from tissue below the epidermal layer. While richomes are generally connected to the vascular system, hair lacks vascular connection.
Hairpin
Double helical region formed by base pairing between adjacent complementary sequences in a single-stranded RNA or DNA. Similar to stem-loop structure.
Hairpin
β – Hairpin
A supersecondary structure in proteins in which two antiparallel β-strands are joined by a loop.
Hairpin ribozymes
Trans-cleaving molecules of 70 nucleotides in length whose conserved domains form a hairpin-like shape. They catalyse simple self-cleaving reactions of phosphodiester bonds and can be produced naturally or synthetically.
Hairy root culture
A recent development in plant culture consisting of highly branched roots of a plant. When a plant tissue is treated with a culture of the bacterium Agrobacterium rhizogenes, part of the plasmid DNA is transferred to the plant cells. This causes metabolic changes in the plant, including alterations in hormone levels. As a consequence of these changes, highly branched much more extensively than the usual root system of that plant, and are also covered with a mass of tiny root hairs. The most significant feature is the production of secondary metabolites at levels similar to those made in the original plant. These are therefore used as replacement plants for making compounds such as food flavours of fragrances.
Half-life
The time required for the decay or disappearance of fifty per cent of a given component system.
Half-register
A repeat unit that can be divided into two halves. This refers to a misalignment of the two chromosomal copies such that the first half of a repeat is aligned with the second half of the other chromosomal copy.
Halophile
Bacteria that require sodium chloride as an essential nutrient.
Halothane
A volatile anaesthetic.
HAMA response
Human Anti-Mouse Antibody. An antibody made by humans against mouse monoclonal antibodies that is used in the treatment of autoimmunity or cancer.
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