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hemolysis

(hĭmŏl`ĭsĭs), destruction of red blood cells in the bloodstream. Although new red blood cells, or erythrocytes, are continuously created and old ones destroyed, an excessive rate of destruction sometimes occurs. The dead cells, in sufficiently large numbers, overwhelm the organ that destroys them, the spleen, so that serum pigments resulting from hemoglobin breakdown appear in the blood serum. Jaundicejaundice
, abnormal condition in which the body fluids and tissues, particularly the skin and eyes, take on a yellowish color as a result of an excess of bilirubin. During the normal breakdown of old erythrocytes (red blood cells), their hemoglobin is converted into bilirubin.
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 is caused by overloading the liver with pigment. Large-scale destruction of red blood cells, from any of a variety of causes, results in anemiaanemia
, condition in which the concentration of hemoglobin in the circulating blood is below normal. Such a condition is caused by a deficient number of erythrocytes (red blood cells), an abnormally low level of hemoglobin in the individual cells, or both these conditions
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. Rh disease, or erythroblastosis fetaliserythroblastosis fetalis
, hemolytic disease of a newborn infant caused by blood group incompatibility between mother and child. Although the Rh factor is responsible for the most severe cases of erythroblastosis fetalis, the disease may be produced by any of the other blood
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, is a hemolytic disease of newborns caused by an immune reaction between fetal red blood cells and maternal antibodies to them. Some hemolytic conditions, e.g., those in which red blood cells are fragile and rupture easily, are treated by removal of the spleen to slow cell breakdown or by administration of steroidssteroids,
class of lipids having a particular molecular ring structure called the cyclopentanoperhydro-phenanthrene ring system. Steroids differ from one another in the structure of various side chains and additional rings. Steroids are common in both plants and animals.
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. Autoimmune hemolytic conditions result from splenomegaly. The spleen not only sequesters red blood cells, but produces antibodies against the body's red blood cells. This is a potentially lethal condition that occurs more often in women than men.

Hemolysis

 

(hematolysis, erythrocytolysis), the destruction of erythrocytes, accompanied by the release of hemoglobin into the surrounding medium.

Physiological hemolysis, a process that completes the 120-day life cycle of the erythrocyte, takes place continuously in man and animals. Under normal physiological conditions 0.8 percent of all the erythrocytes—usually the “aging” ones—undergo lysis. The final decomposition of these aging erythrocytes takes place primarily in the spleen. When the erythrocytes are decomposed bilirubin, one of the bile pigments, is formed from the liberated hemoglobin through a series of complex transformations; the extent of hemolysis can therefore be judged from the amount of bilirubin in the blood and bilirubin derivatives in the feces and urine. The iron liberated in the breakdown of hemoglobin is deposited in the reticuloendothelial cells of the liver and spleen. After complex transformations, this iron is bound to the beta globulin fraction of blood albumin and then takes part in the formation of new hemoglobin.

Disruption of the balance between the lytic agent and the inhibitor may lead to the predominance of blood destruction over blood formation—in other words, to pathological hemolysis. Pathological hemolysis occurs in hemolytic anemias and hemoglobinopathies. It may result from hemolytic poisons (such as certain bacterial toxins, lead, arsenic, nitrobenzene, and morel toxin), from the formation of autoimmune and isoerythrocytic antibodies following the transfusion of incompatible blood, from Rh conflict in the newborn, from the action of certain chemical agents and cold, and, in sensitive individuals, after taking certain drugs or inhaling some types of pollen. In pathological hemolysis, erythrocytes are destroyed in all cells of the reticuloendothelial system (for example, in the liver, bone marrow, or lymph nodes) and also possibly in the bloodstream. In this case most of the hemoglobin of the destroyed erythrocytes is bound to a specific protein (haptoglobin) while the excess passes through the renal filter into the urine (hemoglobinuria). The destruction of a large mass of erythrocytes at once, such as in hemolytic anemias, may be accompanied by a serious condition (hemolytic shock) which may result in death.

Hemolysis may occur in blood that has been stored for a long time, rendering it no longer suitable for ordinary transfusions.

A. M. POLIANSKAIA

hemolysis

[hē′mäl·ə·səs]
(physiology)
The lysis, or destruction, of erythrocytes with the release of hemoglobin.
References in periodicals archive ?
Jaundice may be present; serum bilirubin levels rise as a result of haemolysis (6).
Increased oxidant stress caused by exposure to aniline, its metabolites, methylene blue and the lack of G6PD protective effect against this oxidant stress may have contributed towards inducing haemolysis in our patient.
Assay for phenylhydrazine induced haemolysis of erythrocytes (membrane stabilization study): 20% PCV (packed cell volume) of erythrocyte suspension (from human blood) was prepared according to the procedure described by Hill and Thornalley (1983).
Of the more than 60% of appropriately transfused units, disseminated intravascular haemolysis and massive transfusions accounted for more than 60%.
Approach to anaemia in HIV Reduced red cell production Increased red cell loss Related to HIV Related to HIV Infection Haemolysis HIV itself, mycobacteriae, TTP, autoimmune haemolytic anaemia parvovirus, fungi Malignancy Blood loss High-grade NHL, HL Gastrointestinal, high-grade NHL, Kaposi sarcoma, infection (CMV, Drugs Candida) Zidovudine, co-trimoxazole, isoniazid Hypersplenism Anaemia of chronic disease Infection, lymphoma Unrelated to HIV Unrelated to HIV Haematinic deficiencies Haemolysis Iron, vitamin [B.
On postoperative day three, in addition to deteriorating renal function, blood analysis showed anaemia (haemoglobin 80 g/1) and intravascular haemolysis (serum haptoglobin lower than 0.
Discrepancy between visual and spectrophotometric assessment of sample haemolysis.
1-5) The aetiopathogenesis of HIV-related anaemia is complex and multifactorial, including HIV itself, co-morbid opportunistic infections, AIDS-associated malignancies, drugs, haemolysis, malnutrition, malabsorption or myelodysplasia.
It is more valuable in the diagnosis of haemolysis and haemochromatosis (when significant elevation can occur) than in the diagnosis of iron deficiency.
It is believed that iron released by haemolysis is available for reutilization and that iron deficiency is uncommon in theses conditions.
Up-regulation of the expression of cellular TfR occurs as a result of an inadequate tissue supply of iron or increased cellular demand for iron, therefore, elevation of soluble form of TfR (sTfR) can be detected in any disease causing alteration of iron metabolism especially for the anaemia and haemolysis.
Severe inclusion body /3-thalassaemia with haemolysis in a patient double heterozygous for R[degrees]-thalassaemia and quadruplicated [alpha]-globin gene arrangement of the anti-4.