Red blood cell - Knowledge

327: 6757: 2197: 2185: 2377: 947: 572: 997: 318: 743: 31: 551: 6821: 580: 464: 2480:: first about 1 litre of their blood is extracted, then the red blood cells are isolated, frozen and stored, to be reinjected shortly before the competition. (Red blood cells can be conserved for 5 weeks at −79 °C or −110 °F, or over 10 years using cryoprotectants) This practice is hard to detect but may endanger the human 688:. The argument runs as follows: Efficient gas transport requires red blood cells to pass through very narrow capillaries, and this constrains their size. In the absence of nuclear elimination, the accumulation of repeat sequences is constrained by the volume occupied by the nucleus, which increases with genome size. 1155:– The following membrane proteins establish linkages with skeletal proteins and may play an important role in regulating cohesion between the lipid bilayer and membrane skeleton, likely enabling the red cell to maintain its favorable membrane surface area by preventing the membrane from collapsing (vesiculating). 961:

The proteins of the membrane skeleton are responsible for the deformability, flexibility and durability of the red blood cell, enabling it to squeeze through capillaries less than half the diameter of the red blood cell (7–8 μm) and recovering the discoid shape as soon as these cells stop receiving

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acts as a reservoir of red blood cells, but this effect is somewhat limited in humans. In some other mammals such as dogs and horses, the spleen sequesters large numbers of red blood cells, which are dumped into the blood during times of exertion stress, yielding a higher oxygen transport capacity.

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Typical mammalian red blood cells: (a) seen from surface; (b) in profile, forming rouleaux; (c) rendered spherical by water; (d) rendered crenate (shrunken and spiky) by salt. (c) and (d) do not normally occur in the body. The last two shapes are due to water being transported into, and out of, the

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There are currently more than 50 known membrane proteins, which can exist in a few hundred up to a million copies per red blood cell. Approximately 25 of these membrane proteins carry the various blood group antigens, such as the A, B and Rh antigens, among many others. These membrane proteins can

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alone is straw-colored, but the red blood cells change color depending on the state of the hemoglobin: when combined with oxygen the resulting oxyhemoglobin is scarlet, and when oxygen has been released the resulting deoxyhemoglobin is of a dark red burgundy color. However, blood can appear bluish

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Animation of a typical human red blood cell cycle in the circulatory system. This animation occurs at a faster rate (~20 seconds of the average 60-second cycle) and shows the red blood cell deforming as it enters capillaries, as well as the bars changing color as the cell alternates in states of

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Blood is often transfused when there is known anaemia, active bleeding, or when there is an expectation of serious blood loss, such as prior to an operation. Before blood is given, a small sample of the recipient's blood is tested with the transfusion in a process known as

829:" proteins that move phospholipids in both directions at the same time, down their concentration gradients in an energy-independent manner. There is still considerable debate ongoing regarding the identity of these membrane maintenance proteins in the red cell membrane. 726:, besides its lipidic main constituents; and the membrane skeleton, a structural network of proteins located on the inner surface of the lipid bilayer. Half of the membrane mass in human and most mammalian red blood cells are proteins. The other half are lipids, namely 862:

An exposure of PS can potentiate adhesion of red cells to vascular endothelial cells, effectively preventing normal transit through the microvasculature. Thus it is important that PS is maintained only in the inner leaflet of the bilayer to ensure normal blood flow in

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Thus, the function of the circulatory system is as much about the transport of carbon dioxide as about the transport of oxygen. As stated elsewhere in this article, most of the carbon dioxide in the blood is in the form of bicarbonate ion. The bicarbonate provides a

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Adult humans have roughly 20–30 trillion red blood cells at any given time, constituting approximately 70% of all cells by number. Women have about 4–5 million red blood cells per microliter (cubic millimeter) of blood and men about 5–6 million;

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of carbon dioxide in the alveoli causes carbon dioxide to diffuse rapidly from the capillary into the alveoli. The carbonic anhydrase in the red cells keeps the bicarbonate ion in equilibrium with carbon dioxide. So as carbon dioxide leaves the capillary, and

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in equal proportions by weight. The lipid composition is important as it defines many physical properties such as membrane permeability and fluidity. Additionally, the activity of many membrane proteins is regulated by interactions with lipids in the bilayer.

634:. Each hemoglobin molecule carries four heme groups; hemoglobin constitutes about a third of the total cell volume. Hemoglobin is responsible for the transport of more than 98% of the oxygen in the body (the remaining oxygen is carried dissolved in the 966:

perform a wide diversity of functions, such as transporting ions and molecules across the red cell membrane, adhesion and interaction with other cells such as endothelial cells, as signaling receptors, as well as other currently unknown functions. The

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was mixed with red blood cells, thus identifying compatible and conflicting combinations between these blood groups. A year later Alfred von Decastello and Adriano Sturli, two colleagues of Landsteiner, identified a fourth blood group—AB.

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is a genetic disease that results in abnormal hemoglobin molecules. When these release their oxygen load in the tissues, they become insoluble, leading to mis-shaped red blood cells. These sickle shaped red cells are less deformable and

508:). Members of this order have clearly evolved a mode of red blood cell development substantially different from the mammalian norm. Overall, mammalian red blood cells are remarkably flexible and deformable so as to squeeze through tiny 1946:, red blood cell programmed death. This process normally occurs at the same rate of production by erythropoiesis, balancing the total circulating red blood cell count. Eryptosis is increased in a wide variety of diseases including 3864:

Acid Base Status: The transport of CO2 has a profound effect on the acid-base status of blood and the body as a whole. The lung excretes over 10,000 mEq of carbonic acid per day compared to less than 100 mEq of fixed acids by the

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There is an immense size variation in vertebrate red blood cells, as well as a correlation between cell and nucleus size. Mammalian red blood cells, which do not contain nuclei, are considerably smaller than those of most other

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blood, higher concentrations of oxygen, and better diffusion of oxygen from the blood to the tissues. The size of red blood cells varies widely among vertebrate species; red blood cell width is on average about 25% larger than

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The maintenance of an asymmetric phospholipid distribution in the bilayer (such as an exclusive localization of PS and PIs in the inner monolayer) is critical for the cell integrity and function due to several reasons:

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is an electrochemical property of cell surfaces that is determined by the net electrical charge of molecules exposed at the surface of cell membranes of the cell. The normal zeta potential of the red blood cell is

443:, forming carboxyhemoglobin which is a very bright red in color. Flushed, confused patients with a saturation reading of 100% on pulse oximetry are sometimes found to be suffering from carbon monoxide poisoning. 4054:

carbon dioxide diffuses out of the tissue cells in the gaseous form (but not to a significant effect in the bicarbonate form because the cell membrane is far less permeable to bicarbonate than to the dissolved

1013:– Anion transporter, also an important structural component of the red blood cell membrane, makes up to 25% of the cell membrane surface, each red cell contains approximately one million copies. Defines the 2314:

to ensure that donors do not contain risk factors for the presence of blood-borne diseases, or will not suffer themselves by giving blood. Blood is usually collected and tested for common or serious

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provided another microscopic description in 1674, this time providing a more precise description of red blood cells, even approximating their size, "25,000 times smaller than a fine grain of sand".

484:-shaped rim on the edge of the disk. This shape allows for a high surface-area-to-volume (SA/V) ratio to facilitate diffusion of gases. However, there are some exceptions concerning shape in the 446:

Having oxygen-carrying proteins inside specialized cells (as opposed to oxygen carriers being dissolved in body fluid) was an important step in the evolution of vertebrates as it allows for less

1739:, a signalling gas that acts to relax vessel walls. It is believed that the cardioprotective effects of garlic are due to red blood cells converting its sulfur compounds into hydrogen sulfide. 1401: 5029:

A team of researchers led by the National Health Service (NHS) Blood and Transplant unit recently launched the first clinical trial to transfuse lab-grown red blood cells into a live human.

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red cells that expose PS at their outer surface. Thus the confinement of PS in the inner monolayer is essential if the cell is to survive its frequent encounters with macrophages of the

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in mammals consist of two forms: normoblasts, which are normal erythropoietic precursors to mature red blood cells, and megaloblasts, which are abnormally large precursors that occur in

352:); they live in very oxygen-rich cold water and transport oxygen freely dissolved in their blood. While they no longer use hemoglobin, remnants of hemoglobin genes can be found in their 286:. Each circulation takes about 60 seconds (one minute). Approximately 84% of the cells in the human body are the 20–30 trillion red blood cells. Nearly half of the blood's volume ( 5201: 1665:

In summary, carbon dioxide produced by cellular respiration diffuses very rapidly to areas of lower concentration, specifically into nearby capillaries. When it diffuses into a RBC, CO

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and humans, have red blood cells. Red blood cells are cells present in blood to transport oxygen. The only known vertebrates without red blood cells are the crocodile icefish (family

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Gulliver G (1875). "On the size and shape of red corpuscles of the blood of vertebrates, with drawings of them to a uniform scale, and extended and revised tables of measurements".

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had been successfully coaxed into becoming red blood cells in the lab. The difficult step was to induce the cells to eject their nucleus; this was achieved by growing the cells on

2060:(or anaemias) are diseases characterized by low oxygen transport capacity of the blood, because of low red cell count or some abnormality of the red blood cells or the hemoglobin. 1852:

to mature red blood cells in about 7 days. When matured, in a healthy individual these cells live in blood circulation for about 100 to 120 days (and 80 to 90 days in a full term

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that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The

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on the cell's surface. After this process, the blood is stored, and within a short duration is used. Blood can be given as a whole product or the red blood cells separated as

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is rapidly converted by the carbonic anhydrase found on the inside of the RBC membrane into bicarbonate ion. The bicarbonate ions in turn leave the RBC in exchange for

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In plasma about 5% of CO2 is in physical solution 94% as bicarbonate and 1% as carbamino compounds; in the erythrocytes the corresponding figures are 7%, 82% and 11%.

5937: 6119: 5247: 638:). The red blood cells of an average adult human male store collectively about 2.5 grams of iron, representing about 65% of the total iron contained in the body. 5194: 5982: 106: 5252: 3543:

Yazdanbakhsh K, Lomas-Francis C, Reid ME (October 2000). "Blood groups and diseases associated with inherited abnormalities of the red blood cell membrane".

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The second major contribution of RBC to carbon dioxide transport is that carbon dioxide directly reacts with globin protein components of hemoglobin to form

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Unlike cholesterol, which is evenly distributed between the inner and outer leaflets, the 5 major phospholipids are asymmetrically disposed, as shown below:

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Tilton WM, Seaman C, Carriero D, Piomelli S (August 1991). "Regulation of glycolysis in the erythrocyte: role of the lactate/pyruvate and NAD/NADH ratios".

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is the process by which new red blood cells are produced; it lasts about 7 days. Through this process red blood cells are continuously produced in the red

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is the most common anemia; it occurs when the dietary intake or absorption of iron is insufficient, and hemoglobin, which contains iron, cannot be formed.

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The functional lifetime of a red blood cell is about 100–120 days, during which time the red blood cells are continually moved by the blood flow push (in

2570: 593: 5543: 5187: 2146:, causing the cells to be small, sphere-shaped, and fragile instead of donut-shaped and flexible. These abnormal red blood cells are destroyed by the 492:

including cattle, deer, and their relatives), which displays a wide variety of bizarre red blood cell morphologies: small and highly ovaloid cells in

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plays many roles in this. These functions are highly dependent on the membrane composition. The red blood cell membrane is composed of 3 layers: the

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Ulker P, Sati L, Celik-Ozenci C, Meiselman HJ, Baskurt OK (2009). "Mechanical stimulation of nitric oxide synthesizing mechanisms in erythrocytes".

2241:(or erythrocytoses) are diseases characterized by a surplus of red blood cells. The increased viscosity of the blood can cause a number of symptoms. 1454:

is transported as bicarbonate. At physiological pH the equilibrium strongly favors carbonic acid, which is mostly dissociated into bicarbonate ion.

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The most common red blood cell membrane lipids, schematically disposed as they are distributed on the bilayer. Relative abundances are not at scale.

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The H+ ions released by this rapid reaction within RBC, while still in the capillary, act to reduce the oxygen binding affinity of hemoglobin, the

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and a thickness at the thickest point of 2–2.5 μm and a minimum thickness in the centre of 0.8–1 μm, being much smaller than most other

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colocated in the RBC membrane. The bicarbonate ion does not diffuse back out of the capillary, but is carried to the lung. In the lung the lower

1978:. Excessive eryptosis is observed in red blood cells lacking the cGMP-dependent protein kinase type I or the AMP-activated protein kinase AMPK. 1162:-based macromolecular complex – proteins linking the bilayer to the membrane skeleton through the interaction of their cytoplasmic domains with 5581: 2426:, which are variations in red blood cell shape. When red blood cells sometimes occur as a stack, flat side next to flat side. This is known as 1974:. Eryptosis can be elicited by osmotic shock, oxidative stress, and energy depletion, as well as by a wide variety of endogenous mediators and 608:

with low oxygen tension will have more. Red blood cells are thus much more common than the other blood particles: there are about 4,000–11,000

1856:). At the end of their lifespan, they are removed from circulation. In many chronic diseases, the lifespan of the red blood cells is reduced. 1662:. That is, there is always an abundance of bicarbonate in blood, both venous and arterial, because of its aforementioned role as a pH buffer. 2001:

Much of the resulting breakdown products are recirculated in the body. The heme constituent of hemoglobin are broken down into iron (Fe) and

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This asymmetric phospholipid distribution among the bilayer is the result of the function of several energy-dependent and energy-independent

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Red blood cells in mammals are unique amongst vertebrates as they do not have nuclei when mature. They do have nuclei during early phases of

504:), and cells which assume fusiform, lanceolate, crescentic, and irregularly polygonal and other angular forms in red deer and wapiti (family 326: 6112: 1967: 1791: 519:, but extrude them during development as they mature; this provides more space for hemoglobin. The red blood cells without nuclei, called 6626: 6239: 5819: 2523:

in Bologna was able to demonstrate the presence of iron by passing magnets over the powder or ash remaining from heated red blood cells.

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Jiang N, Tan NS, Ho B, Ding JL (October 2007). "Respiratory protein-generated reactive oxygen species as an antimicrobial strategy".

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parasite spends part of its life-cycle in red blood cells, feeds on their hemoglobin and then breaks them apart, causing fever. Both

1240:– defines the Kell Blood Group and the Mcleod unusual phenotype (lack of Kx antigen and greatly reduced expression of Kell antigens); 4026:

Despite being a heavier molecule, because it is more soluble, the relative rate of diffusion of CO2 is about 20 times the rate of O2

1906:) and a combination of the two as they squeeze through microvessels such as capillaries. They are also recycled in the bone marrow. 669:, where five different clades has evolved various degrees of enucleated red blood cells (most evolved in some species of the genus 6746: 3238:

McLaren CE, Brittenham GM, Hasselblad V (April 1987). "Statistical and graphical evaluation of erythrocyte volume distributions".

6105: 1812:(although it does contain RNAs), and consequently cannot divide and have limited repair capabilities. The inability to carry out 3168:

Goodman SR, Kurdia A, Ammann L, Kakhniashvili D, Daescu O (December 2007). "The human red blood cell proteome and interactome".

878:. Recent studies have shown that binding of spectrin to PS promotes membrane mechanical stability. PIP2 enhances the binding of 706:

Red blood cells are deformable, flexible, are able to adhere to other cells, and are able to interface with immune cells. Their

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as the sack. Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the

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Denomme GA (July 2004). "The structure and function of the molecules that carry human red blood cell and platelet antigens".

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very rapidly, while the red cells are still moving through the capillary. Thus it is the RBC that ensures that most of the CO

867: 512:, as well as to maximize their apposing surface by assuming a cigar shape, where they efficiently release their oxygen load. 6736: 1426:

transport process, for two reasons. First, because, besides hemoglobin, they contain a large number of copies of the enzyme

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are typically shaped as biconcave disks: flattened and depressed in the center, with a dumbbell-shaped cross section, and a

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on the inside of their cell membrane. Carbonic anhydrase, as its name suggests, acts as a catalyst of the exchange between

825:" do the opposite operation, against a concentration gradient in an energy-dependent manner. Additionally, there are also " 575:

Two drops of blood are shown with a bright red oxygenated drop on the left and a darker red deoxygenated drop on the right.

5127: 3725:"Clinical and Functional Relevance of the Monocarboxylate Transporter Family in Disease Pathophysiology and Drug Therapy" 2330:(A, B, AB, or O) or the blood product is identified and matched with the recipient's blood to minimise the likelihood of 1067:– gas transporter, probably of carbon dioxide, defines Rh Blood Group and the associated unusual blood group phenotype Rh 987: 3998:

from figure 41-5 Hgb.CO2 is about 23% and bicarbonate is about 70% of the total carbon dioxide transported to the lungs.

2534:—A, B, and C (which he later renamed to O). Landsteiner described the regular patterns in which reactions occurred when 859:

and sickle red cells has been linked to disruptions of lipid asymmetry leading to exposure of PS on the outer monolayer.

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with a surface area of about 136 μm, and can swell up to a sphere shape containing 150 fL, without membrane distension.

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from the bone marrow. It is hoped that these artificial red blood cells can eventually be used for blood transfusions.

1447: 1319:, as illustrated schematically here with a unit of carbohydrate, produces about as many molecules of carbon dioxide, CO 951: 926:

that have been implicated in cell signaling events in nonerythroid cells have been shown in erythroid cells to mediate

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Gregory TR (2001). "The bigger the C-value, the larger the cell: genome size and red blood cell size in vertebrates".

1333: 6791: 5857: 4651: 4495: 4416:"Red blood cells do more than just carry oxygen; New findings by NUS team show they aggressively attack bacteria too" 4136: 4104: 4076: 4047: 4019: 3991: 3945: 3917: 3889: 3857: 3829: 3222: 6824: 6771: 6731: 6694: 1886:(EPO), synthesised by the kidney. Just before and after leaving the bone marrow, the developing cells are known as 684:

The elimination of the nucleus in vertebrate red blood cells has been offered as an explanation for the subsequent

113: 2118:, meaning that they have become rigid and can cause blood vessel blockage, pain, strokes, and other tissue damage. 3806:

Tokumasu F, Ostera GR, Amaratunga C, Fairhurst RM (2012) Modifications in erythrocyte membrane zeta potential by

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Rodi PM, Trucco VM, Gennaro AM (June 2008). "Factors determining detergent resistance of erythrocyte membranes".

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diameter, and it has been hypothesized that this improves the oxygen transfer from red blood cells to tissues.

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The Respiratory Exchange Ratio is 1:1 when carbohydrate is consumed, it is as low as 0.7 when fat is consumed.

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is the general term for excessive breakdown of red blood cells. It can have several causes and can result in

1713:, which also act to dilate blood vessels, thus directing more blood to areas of the body depleted of oxygen. 974:

of red blood cells. Disorders of the proteins in these membranes are associated with many disorders, such as

101: 3037: 2017:. Almost all red blood cells are removed in this manner from the circulation before they are old enough to 6509: 6317: 5892: 5746: 2422:(or peripheral blood smear), where a thin layer of blood is smeared on a microscope slide. This may reveal 2268: 1927: 1133: 870:(PIP2) can regulate membrane mechanical function, due to their interactions with skeletal proteins such as 754:, similar to what can be found in virtually all human cells. Simply put, this lipid bilayer is composed of 1690:

on hemoglobin, sufficient bicarbonate ion converts rapidly to carbon dioxide to maintain the equilibrium.

5762: 5173: 2196: 1044: 898:" in the red blood cell membrane have been described by recent studies. These are structures enriched in 5101: 3677:

Hempelmann E, Götze O (1984). "Characterization of membrane proteins by polychromatic silver staining".

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the Iceman, a natural mummy of a man who died around 3255 BCE. These cells were discovered in May 2012.

2433:, and it occurs more often if the levels of certain serum proteins are elevated, as for instance during 4638:

Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter (2002).

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are more common in malaria areas, because these mutations convey some protection against the parasite.

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Wingstrand KG (1956). "Non-nucleated erythrocytes in a teleostean fish Maurolicus mülleri (Gmelin)".

2595: 1787: 1408: 1092: 983: 979: 659:. In comparison, the red blood cells of other vertebrates have nuclei; the only known exceptions are 244: 3283:

Bianconi E, Piovesan A, Facchin F, Beraudi A, Casadei R, Frabetti F, et al. (1 November 2013).

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A human trial is conducted in 2022, using blood cultured from stem cells obtained from donor blood.

1824:) can affect erythroid precursors while they still have DNA, as recognized by the presence of giant 1446:

transport by hemoglobin. In the presence of this catalyst carbon dioxide and carbonic acid reach an

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from another person, or stored by the recipient at an earlier date. Donated blood usually requires

2139: 1942:), thus removing old and defective cells and continually purging the blood. This process is termed 1779: 1316: 975: 927: 919: 794: 691: 89: 77: 5179: 5047:. American Association of Blood Banks, American Red Cross, America's Blood Centers. Archived from 6717: 6673: 6592: 6461: 6086: 6037: 6017: 5664: 5517: 2473:, the red blood cells are pumped back into the body right away and only the plasma is collected. 1766:, red blood cells use none of the oxygen they transport; instead they produce the energy carrier 1141: 1137: 330:

Mature red blood cells of birds have a nucleus, however in the blood of adult females of penguin

274:, to accommodate maximum space for hemoglobin; they can be viewed as sacks of hemoglobin, with a 4038: