haem


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heme

(hēm)
1. The porphyrin chelate of iron in which the iron is Fe(II) (Fe2+); the oxygen-carrying, color-furnishing, prosthetic group of hemoglobin.
2. Iron complexed with nonporphyrins but related tetrapyrrole structures (e.g., biliverdin heme).
Synonym(s): reduced hematin, haem.
[G. haima, blood]

haem

or

heme

a ring-like chemical structure containing an atom of ferrous iron that is bound as a PROSTHETIC GROUP to each POLYPEPTIDE CHAIN within HAEMOGLOBIN and MYOGLOBIN, giving blood and muscle their characteristic red colour.

heme

(hēm)
1. The oxygen-carrying, color-furnishing, prosthetic group of hemoglobin.
2. Iron complexed with nonporphyrins but related tetrapyrrole structures.
Synonym(s): reduced hematin, haem.
[G. haima, blood]
References in periodicals archive ?
Although irrelevant in this case, if there is the potential for significant blood loss, circulating haemoglobin levels should be rigidly maintained with transfusions, avoiding the risk of intra-operative stimulation of haem synthesis precipitating a porphyric crisis (1).
Vitamin B6 is required for haem synthesis and therefore for erythropoiesis.
The porphyrias are a heterogeneous group of inherited metabolic disorders associated with defects in haem biosynthesis.
Primary acquired sideroblastic anaemia, which involves abnormal haematopoiesis, is idiopathic, as it is not clear what the cause of defective haem synthesis is in the abnormal erythroid clone (3) This type of sideroblastic anaemia is the one most commonly seen in the haematology laboratory, as it is part of the myelodysplastic syndromes--a series of clonal haematopoietic stem cell diseases.
Haem iron is readily absorbed by the body whereas non-haem iron is less soluble in the gut and therefore less is absorbed.
Diets that are low in iron, high in inhibitors, with little haem iron intake, are the most common causes of iron deficiency.
Agents like nitrates, nitrites, chlorates and quinones oxidise haem iron directly.
In December 2003, I reported on a study that found that doses of the GBE extract EGb761 as high as 480 mg/day had no effect on bleeding time, platelet aggregation, and coagulation in a group of healthy male volunteers (Clin Lab Haem, 2003; 25:251-53).
"Vegetable sources of iron include prunes and spring greens, but they contain a form that is less well absorbed than the haem iron found in animal products, so don't over-boil vegetables as this decreases their iron availability.
Suffering from a rare blood disease known as porphyria, Raven's blood lacks a key ingredient called haem. Although doctors insist that drinking blood doesn't curb the disease, Raven, 29, is adamant it alleviates his painful symptoms.
The type of iron found in meat is known as haem iron, which is the same as the iron found in the blood and is therefore easy to absorb into the body.
N Naidoo, (1) MB BCh, MPH; A Abayomi, (1) MBBS, MRCP, FCPath, MPhil, DHSM; C Locketz, (2) MB ChB, FC Path (Anat), MMed (Anat Path); F Musaigwa, (1) MPath (Haem Path); R Grewal, (1) MB ChB, FC Path (Haem), MMed (Haem Path)