Erythrocytes: From 1 Different Sources
The biconcave red blood cells that carry oxygen from the lungs to the tissues, and return carbon dioxide (see also RESPIRATION). They have an excess of membrane, some of which may be lost in various disorders, as a result of which they become progressively more spherical and rigid. Erythrocytes, which have no nuclei, are formed during ERYTHROPOEISIS from ERYTHROBLASTS in the BONE MARROW, and each mm3 of blood contains 5 million of them. They are by far the largest constituent among the blood cells and they contain large amounts of the oxygen-carrier HAEMOGLOBIN. They have a life of about 120 days after which they are absorbed by macrophages (see MACROPHAGE), the blood’s scavenging cells. Most components of the erythrocytes, including the red pigment haemoglobin, are re-used, though some of the pigment is broken down to the waste product BILIRUBIN.
The abbreviation for erythrocyte sedimentation rate, which is the rate at which erythrocytes (red blood cells) sink to the bottom of a test tube. The is increased if the level of fibrinogen (a type of protein) in the blood is raised. Fibrinogen is raised in response to a range of illnesses, including inflammation, especially when this is caused by infection or by an autoimmune disease. The is also increased if levels of immunoglobulins are very high, as occurs in multiple myeloma. is therefore useful for helping to diagnose these conditions as well as in monitoring their treatment.... esr
Linn.
Family: Papilionaceae; Fabaceae.
Habitat: Throughout the country, ascending to an altitude of about 1,050 m in the outer Himalayas.
English: Indian Wild Liquorice, Jequirity, Crab's Eye, Precatory Bean.
Ayurvedic: Gunjaa, Gunjaka, Chirihintikaa, Raktikaa, Chirmi- ti, Kakanti, Kabjaka, Tiktikaa, Kaakananti, Kaakchinchi. (Not to be used as a substitute for liquorice.)
Unani: Ghunghchi, Ghamchi.
Siddha/Tamil: Kunri.
Folk: Chirmiti, Ratti.
Action: Uterine stimulant, abortifa- cient, toxic. Seeds—teratogenic. A paste of seeds is applied on vitiligo patches.
Along with other therapeutic applications, The Ayurvedic Pharmacopoeia of India has indicated the use of seeds in baldness.Seeds contain abrin, a toxalbumin, indole derivatives, anthocyanins, ste- rols, terpenes. Abrin causes agglutination of erythrocytes, haemolysis and enlargement of lymph glands. A non- toxic dose of abrin (1.25 mcg/kg body weight), isolated from the seeds of red var., exhibited a noticeable increase in antibody-forming cells, bone marrow cellularity and alpha-esterase-positive bone marrow cells.Oral administration of agglutinins, isolated from the seeds, is useful in the treatment of hepatitis and AIDS.The seed extract exhibited antischis- tosomal activity in male hamsters.The methanolic extract of seeds inhibited the motility of human spermatozoa.The roots contain precol, abrol, gly- cyrrhizin (1.5%) and alkaloids—abra- sine and precasine. The roots also contain triterpenoids—abruslactone A, methyl abrusgenate and abrusgenic acid.Alkaloids/bases present in the roots are also present in leaves and stems.A. fruticulosus Wall. Ex Wight and Arn. synonym A. pulchellus Wall., A. laevigatus E. May. (Shveta Gunjaa) is also used for the same medicinal purposes as A. precatorius.
Dosage: Detoxified seed—1-3 g powder. Root powder—3-6 g. (API Vols. I, II.)... abrus precatorius
This means inequality in the size of erythrocytes (red blood cells); it occurs in many forms but is prominent in megaloblastic ANAEMIA.... anisocytosis
A blood clot arises when blood comes into contact with a foreign surface – for example, damaged blood vessels – or when tissue factors are released from damaged tissue. An initial plug of PLATELETS is converted to a de?nitive clot by the deposition of FIBRIN, which is formed by the clotting cascade and erythrocytes. (See COAGULATION.)... blood clot
See ERYTHROCYTES and LEUCOCYTES.... blood corpuscle
Bone marrow is the soft substance occupying the interior of bones. It is the site of formation of ERYTHROCYTES, granular LEUCOCYTES and PLATELETS.... bone marrow
A drug that curbs the action of an ENZYME in the blood controlling the production of carbonic acid or bicarbonate from CARBON DIOXIDE (CO2). Called carbonic anhydrase, the enzyme is present in ERYTHROCYTES and it has a key part in maintaining the acid-base balance in the blood. Inhibiting drugs include ACETAZOLAMIDE and DORZOLAMIDE, and these are used as weak DIURETICS to reduce the increased intraocular pressure in ocular hypertension or open-angle GLAUCOMA (see EYE, DISORDERS OF).... carbonic anhydrase inhibitor
A series of nucleated cells in the bone marrow that go through various stages of development until they form ERYTHROCYTES. They may appear in the blood in certain diseases.... erythroblasts
The process by which ERYTHROCYTES or red blood cells are produced. The initiating cell is the haemopoietic stem cell from which an identi?able proerythroblast develops. This goes through several stages as a normoblast before losing its nucleus to become an erythrocyte. This process takes place in the blood-forming bone-marrow tissue.... erythropoeisis
The protein, produced mainly in the kidney, that is the major stimulus for the production of ERYTHROCYTES, or red blood corpuscles. It is used when treating ANAEMIA dure to end-stage kidney failure and in premature newborns with anaemia. (See also BLOOD.)... erythropoietin
The feral and congested fluids built up in a bruise or infection. Unlike a transudate, which is merely edema from lymphatic congestion, exudates contain dead cells, erythrocytes, white blood cells and often pus.... exudates
People are divided into four main groups in respect of a certain reaction of the blood. This depends upon the capacity of the serum of one person’s blood to cause the red cells of another’s to stick together (agglutinate). The reaction depends on antigens (see ANTIGEN), known as agglutinogens, in the erythrocytes and on ANTIBODIES, known as agglutinins, in the serum. There are two of each, the agglutinogens being known as A and B. A person’s erythrocytes may have (1) no agglutinogens, (2) agglutinogen A, (3) agglutinogen B, (4) agglutinogens A and B: these are the four groups. Since the identi?cation of the ABO and Rhesus factors (see below), around 400 other antigens have been discovered, but they cause few problems over transfusions.
In blood transfusion, the person giving and the person receiving the blood must belong to the same blood group, or a dangerous reaction will take place from the agglutination that occurs when blood of a di?erent group is present. One exception is that group O Rhesus-negative blood can be used in an emergency for anybody.
| Agglutinogens | Agglutinins | Frequency |
| in the | in the | in Great |
| Group | erythrocytes | plasma | Britain |
| AB | A and B | None | 2 per cent |
| A | A | Anti-B | 46 per cent |
| B | B | Anti-A | 8 per cent |
| O | Neither | Anti-A and | 44 per cent |
| A nor B | Anti-B | |
| | | |
Rhesus factor In addition to the A and B agglutinogens (or antigens), there is another one known as the Rhesus (or Rh) factor – so named because there is a similar antigen in the red blood corpuscles of the Rhesus monkey. About 84 per cent of the population have this Rh factor in their blood and are therefore known as ‘Rh-positive’. The remaining 16 per cent who do not possess the factor are known as ‘Rh-negative’.
The practical importance of the Rh factor is that, unlike the A and B agglutinogens, there are no naturally occurring Rh antibodies. However, such antibodies may develop in a Rh-negative person if the Rh antigen is introduced into his or her circulation. This can occur (a) if a Rh-negative person is given a transfusion of Rh-positive blood, and (b) if a Rh-negative mother married to a Rh-positive husband becomes pregnant and the fetus is Rh-positive. If the latter happens, the mother develops Rh antibodies which can pass into the fetal circulation, where they react with the baby’s Rh antigen and cause HAEMOLYTIC DISEASE of the fetus and newborn. This means that, untreated, the child may be stillborn or become jaundiced shortly after birth.
As about one in six expectant mothers is Rh-negative, a blood-group examination is now considered an essential part of the antenatal examination of a pregnant woman. All such Rh-negative expectant mothers are now given a ‘Rhesus card’ showing that they belong to the rhesus-negative blood group. This card should always be carried with them. Rh-positive blood should never be transfused to a Rh-negative girl or woman.... blood groups
An ENZYME that performs an essential function in the metabolism of CARBOHYDRATE. A de?ciency in this enzyme – acronym G6PD – results in the breakdown of ERYTHROCYTES (HAEMOLYSIS), usually in the presence of oxidants (see OXIDANT) such as infections or drugs. The de?ciency disorder is a hereditary condition in which the enzyme is absent. The condition, characterised by pallor, rigors and pain in the loin, is divided into African, European (including FAVISM) and Oriental types. Sufferers should avoid substances that trigger haemolysis. Acute episodes are best treated symptomatically.... glucose-6-phosphate dehydrogenase
An iron-containing porphyrin (see PORPHYRINS) compound that combines with the protein GLOBULIN to make HAEMOGLOBIN, a constituent of erythrocytes (red blood cells).... haem
Also known as packed cell volume, this is an expression of the fraction of blood volume occupied by the ERYTHROCYTES. It is determined by centrifuging a sample of blood in a capillary tube and measuring the height of the resulting packed cells as a percentage of the total sample height. Normal values: males 42–53 per cent or 0.42–0.53 mL/dL females 32–48 per cent or 0.36–0.48 mL/dL... haematocrit
Promoting the breakdown of red blood cells; a normal process, hectic and skillfully balanced, the term is usually applied to excess conditions or toxic substances that degrade the bonds between healthy red blood cells and their hemoglobin coat or cause the liver and spleen to hypercatabolize otherwise healthy erythrocytes.... hemolytic
The latent liver forms in Plasmodium vivax and P.ovale which give rise to clinical relapses of malaria byinvasion of the circulating erythrocytes.The hypnozoites are not eliminated by the usual chemotherapeutic drugs used in the treatment of malaria (chloroquine, quinine etc) and to achieve a radical cure in these relapsing malarias an antirelapse drug must be added to the treatment regime (e.g. primaquine or etaquine/Tefanoquine).... hypnozoite
This forms a small proportion of the total HAEMOGLOBIN in the blood. It di?ers from the major component, HbA, in that it has a glucose group attached. The rate of synthesis of HbA1c is a function of the blood-glucose concentration, and since it accumulates throughout the life span of the red blood cell – normally 120 days – the concentration of HbA1c is related to the mean blood-glucose concentration over the past 3–4 months. It is thus a useful indicator of medium-term diabetic control (see DIABETES MELLITUS) – a good target range would be a concentration of 5–8 per cent. When interpreting the HbA1c level, however, it is important to remember that wide ?uctuations in blood-glucose concentration, together with ANAEMIA or a reduced ERYTHROCYTES life span, may give misleading results.... glycosylated haemoglobin (hba1c)
Macrocyte is an unusually large red blood cell (see ERYTHROCYTES) especially characteristic of the blood in PERNICIOUS ANAEMIA.... macrocyte
A type of white blood cell which has a single kidney-shaped nucleus. Present in the tissues and lymphatic system as well as in the circulation, it ingests foreign particles such as tissue debris and bacteria. Monocytes are about 20 µm in diameter and 1 mm3 of blood contains around 7,500 of them, many times fewer than the ?ve million erythrocytes (red blood cells).... monocyte
The precursor of an erythrocyte (see ERYTHROCYTES; BLOOD) which still contains the remnant of a NUCLEUS.... normoblast
The compound formed when the pigment HAEMOGLOBIN in the ERYTHROCYTES (red blood cells) combines with OXYGEN (a reversible reaction). The oxygen is carried in this way from the lungs to the body’s tissues where it is released to take part in metabolic activities.... oxyhaemoglobin
A fall in the number of red ERYTHROCYTES and white LEUCOCYTES, as well as of platelets (see BLOOD – Composition). The condition is found in aplastic ANAEMIA, tumours of the BONE MARROW, enlarged SPLEEN, and other disorders.... pancytopenia
Leukaemia is an umbrella term for several malignant disorders of white blood cells in which they proliferate in a disorganised manner. The disease is also characterised by enlargement of the SPLEEN, changes in the BONE MARROW, and by enlargement of the LYMPH glands all over the body. The condition may be either acute or chronic.
According to the type of cells that predominate, leukaemia may be classi?ed as acute or chronic lymphoblastic leukaemia or myeloid leukaemia. Acute lymphoblastic leukaemia (ALL) is mostly a disease of childhood and is rare after the age of 25. Acute myeloid leukaemia is most common in children and young adults, but may occur at any age. Chronic lymphatic leukaemia occurs at any age between 35 and 80, most commonly in the 60s, and is twice as common in men as in women. Chronic myeloid leukaemia is rare before the age of 25, and most common between the ages of 30 and 65; men and women are equally affected. Around 2,500 patients with acute leukaemia are diagnosed in the United Kingdom, with a similar number annually diagnosed with chronic leukaemia.
Cause Both types of acute leukaemia seem to arise from a MUTATION in a single white cell. The genetically changed cell then goes through an uncontrolled succession of divisions resulting in many millions of abnormal white cells in the blood, bone marrow and other tissues. Possible causes are virus infection, chemical exposure, radiation and genetic background. The cause of chronic lymphocytic leukaemia is not known; the chronic myeloid version may have a genetic background.
Symptoms In acute cases the patient is pale due to anaemia, may have a purpuric rash due to lack of platelets, and may have enlarged lymphatic glands and spleen. The temperature is raised, and the condition may be mistaken for an acute infection (or may ?rst become apparent because the patient develops a severe infection due to a lack of normal white blood cells).
In the chronic type of the disease the onset is gradual, and the ?rst symptoms which occasion discomfort are either swelling of the abdomen and shortness of breath, due to painless enlargement of the spleen; or the enlargement of glands in the neck, armpits and elsewhere; or the pallor, palpitation, and other symptoms of anaemia which often accompany leukaemia. Occasional bleeding from the nose, stomach, gums or bowels may occur, and may be severe. Generally, there is a slight fever.
When the blood is examined microscopically, not only is there an enormous increase in the number of white cells, which may be multiplied 30- or 60-fold, but various immature forms are also found. In the lymphatic form of the disease, most white cells resemble lymphocytes, which, in healthy blood, are present only in small numbers. In the myeloid form, myelocytes, or large immature cells from the bone marrow, which are never present in healthy blood, appear in large numbers, and there may also be large numbers of immature, nucleated erythrocytes.
Treatment This varies according to the type of leukaemia and to the particular condition of the patient. Excellent results are being obtained in the control of ALL using blood transfusions, CHEMOTHERAPY, RADIOTHERAPY and bone-marrow TRANSPLANTATION. In the case of acute leukaemia, the drugs now being used include MERCAPTOPURINE, METHOTREXATE and CYCLOPHOSPHAMIDE. Blood transfusion and CORTICOSTEROIDS play an important part in controlling the condition during the period before a response to chemotherapy can be expected. Chemotherapy has almost completely replaced radiotherapy in the treatment of chronic leukaemia. For the myeloid form, BUSULFAN is the most widely used drug, replaced by hydroxyurea, mercaptopurine, or one of the nitrogen mustard (see NITROGEN MUSTARDS) derivatives in the later stages of the disease. For the lymphatic form, the drugs used are CHLORAMBUCIL, CYCLOPHOSPHAMIDE, and the nitrogen mustard derivatives.
Prognosis Although there is still no guaranteed cure, the outlook in both acute and chronic leukaemia has greatly improved – particularly for the acute form of the disease. Between 70 and 80 per cent of children with acute lymphoblastic leukaemia may be cured; between 20 and 50 per cent of those with acute myeloid leukaemia now have much-improved survival rates. Prognosis of patients with chronic lymphocytic leukaemia is often good, depending on early diagnosis.... leukaemia
Red blood cells or erythrocytes... rbc
See ERYTHROCYTES; BLOOD.... red blood cell
The term applied to the heaps into which red blood corpuscles (ERYTHROCYTES) collect as seen under the microscope.... rouleaux
(blood corpuscle) any of the cells that are present in the blood in health or disease. The cells may be subclassified into three major categories, namely red cells (*erythrocytes); white cells (*leucocytes), which include granulocytes, lymphocytes, and monocytes; and *platelets (see illustration). The blood cells account for approximately 40% of the total volume of the blood in health; red cells comprise the vast majority.... blood cell
(erythro-) combining form denoting 1. redness. Example: erythuria (excretion of red urine). 2. erythrocytes.... erythr
n. any of a series of nucleated cells (see normoblast; proerythroblast) that pass through a succession of stages of maturation to form red blood cells (*erythrocytes). Erythroblasts are normally present in the blood-forming tissue of the bone marrow, but they may appear in the circulation in a variety of diseases (see erythroblastosis). See also erythropoiesis.... erythroblast
(red blood cell) n. a *blood cell containing the red pigment *haemoglobin, the principal function of which is the transport of oxygen. A mature erythrocyte has no nucleus and its shape is that of a biconcave disc, approximately 7 ?m in diameter. There are normally about 5 ×1012 erythrocytes per litre of blood. See also erythropoiesis.... erythrocyte
Cells, also called blood corpuscles, present in blood for most or part of their lifespan. They include red blood cells, which make up about 45 per cent by volume of normal blood, white blood cells, and platelets. Blood cells are made in the bone marrow by a series of divisions from stem cells.
Red blood cells (also known as RBCs, red blood corpuscles, or erythrocytes) transport oxygen from the lungs to the tissues (see respiration). Each is packed with haemoglobin, enzymes, minerals, and sugars. Abnormalities can occur in the rate at which RBCs are either produced or destroyed, in their numbers, and in their shape, size, and haemoglobin content, causing forms of
anaemia and polycythaemia (see blood, disorders of).
White blood cells (also called WBCs, white blood corpuscles, or leukocytes) protect the body against infection and fight infection when it occurs. The 3 main types of are granulocytes (also called polymorphonuclear leukocytes), monocytes, and lymphocytes. Granulocytes are further classified as neutrophils, eosinophils, or basophils, and each type of granulocyte has a role in either fighting infection or in inflammatory or allergic reactions. Monocytes and lymphocytes also play an important part in the immune system. Lymphocytes are usually formed in the lymph nodes. One type, a T-lymphocyte, is responsible for the delayed hypersensitivity reactions
White (see allergy) and Red blood blood cell is also involved in cell (neutrophil) protection against cancer. T-lymphocytes manufacture chemicals, known as lymphokines, which affect the function of other cells. In addition, the T-cells moderate the activity of B-lymphocytes, which form the antibodies that can prevent a second attack of certain infectious diseases. Platelets (also known as thrombocytes), are the smallest blood cells and are important in blood clotting.
The numbers, shapes, and appearance of the various types of blood cell are of great value in the diagnosis of disease (see blood count; blood film).... blood cells
n. a reduction in the number of red blood cells (*erythrocytes) in the blood. This usually, but not invariably, occurs in *anaemia.... erythropenia
n. a substance contained within the red blood cells (*erythrocytes) and responsible for their colour, composed of the pigment haem (an iron-containing *porphyrin) linked to the protein globin. Haemoglobin has the unique property of combining reversibly with oxygen and is the medium by which oxygen is transported within the body. It takes up oxygen as blood passes through the lungs and releases it as blood passes through the tissues. Blood normally contains 115 to 180 g/l of haemoglobin. See also myoglobin; oxyhaemoglobin.... haemoglobin
n. the destruction of red blood cells (*erythrocytes). Within the body, haemolysis may result from defects within the red cells or from poisoning, infection, or the action of antibodies; it may occur in mismatched blood transfusions. It usually leads to anaemia. Haemolysis of blood specimens may result from unsatisfactory collection or storage or be brought about intentionally as part of an analytical procedure (see laking).... haemolysis
adj. causing, associated with, or resulting from destruction of red blood cells (*erythrocytes). For example, a haemolytic antibody is one that causes destruction of red cells; a haemolytic anaemia is due to red-cell destruction (see anaemia).... haemolytic
(haematocrit) the volume of the red cells (erythrocytes) in blood, expressed as a fraction of the total volume of the blood. The packed cell volume is determined by centrifuging blood in a tube and measuring the height of the red-cell column as a fraction of the total. Automated instruments calculate packed cell volume as the product of the erythrocyte count and the measured mean red cell volume (mean corpuscular volume; MCV).... packed cell volume
(polychromatophilia) n. the presence of certain blue red blood cells (*erythrocytes) seen in blood films stained with *Romanowsky stains, as well as the normal pink cells. The cells that appear blue are juvenile erythrocytes (see reticulocyte).... polychromasia
n. the connective tissue basis of an organ, as opposed to the functional tissue (parenchyma). For example, the stroma of the erythrocytes is the spongy framework of protein strands within a red blood cell in which the blood pigment haemoglobin is packed; the stroma of the cornea is the transparent fibrous tissue making up the main body of the cornea.... stroma
Health Encyclopedia