Blood thrombocytes

The formed elements consist primarily of red blood cells, ie, erythrocytes. Less than 1 /600 of the total volume of the formed elements is composed of white blood cells, ie, leukocytes, and less than 1/800 are platelets, ie, thrombocytes. Table 1 gives the typical constitution of human blood. 

Primary blood components iaclude plasma, red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes), and stem cells. Plasma consists of water dissolved proteias, ie, fibrinogen, albumins, and globulins coagulation factors and nutrients. The principal plasma-derived blood products are siagle-donor plasma (SDP), produced by sedimentation from whole blood donations fresh frozen plasma (FFP), collected both by apheresis and from whole blood collections cryoprecipitate, produced by cryoprecipitation of FFP albumin, collected through apheresis and coagulation factors, produced by fractionation from FFP and by apheresis (see Fractionation, blood-plasma fractionation). 

There are undifferentiated stem cells of the blood elements in the bone marrow that differentiate and mature into erythrocytes, (red blood cells), thrombocytes (platelets), and white blood cells (leukocytes and lymphocytes). The production of erythrocytes is regulated by a hormone, erythropoietin (see the section on kidney toxicity), that is synthetized and excreted by the kidney. An increase in the number of premature erythrocytes is an indication of stimulation of erythropoiesis, i.e., increased production of erythrocytes in anemia due to continuous bleeding. 

Animal cells can modify arachidonic acid and other polyunsaturated fatty acids, in processes often involving cyclization and oxygenation, to produce so-called local hormones that (1) exert their effects at very low concentrations and (2) usually act near their sites of synthesis. These substances include the prostaglandins (PG) (Figure 25.27) as well as thromboxanes (Tx), leukotrienes, and other hydroxyeicosanoic acids. Thromboxanes, discovered in blood platelets (thrombocytes), are cyclic ethers (TxBg is actually a hemiacetal see Figure 25.27) with a hydroxyl group at C-15. 

MANAGING HONE MARROW SUPPRESSION. Bone marrow suppression is a potentially dangerous adverse reaction resulting in decreased production of blood cells. Bone marrow suppression is manifested by abnormal laboratory test results and clinical evidence of leukopenia, thrombocytopenia, or anemia For example, there is a decrease in the white blood cells or leukocytes (leukopenia), a decrease in the thrombocytes (thrombocytopenia), and a decrease in the red blood cells, resulting in anemia Fhtients with leukopenia have a decreased resistance to infection, and the nurse must monitor them closely for any signs of infection. 

In Section 24.3, use of electrosorption for effluent purification was mentioned. The same principle of an electrochemically controlled hemosorption (sorptive blood purification) is used in modem toxicology to extract toxins from blood. By appropriate potential control of the carbon sorbent, particular toxins can be removed selectively without traumatizing the blood, that is, without removing essential blood components such as the thrombocytes. 

The third of the cellular elements within the blood are the platelets (thrombocytes). Platelets are actually small, round or oval cell fragments. They are about 2 to 4 pm in diameter and have no nuclei. Platelets are formed in the red bone marrow as pinched-off portions of the very large megakaryocytes. Each megakaryocyte, which is confined to the bone marrow, can produce... 

Hematological Effects. Routine blood parameters (hemoglobin, erythrocyte, leukocyte and thrombocyte levels) measured in 11 hexachloroethane workers did not differ from those of the controls (Selden et al. 1994). Plasma hexachloroethane levels in these workers, who wore protective equipment, were 7.3 + 6.04 pg/L at the time of the hematological analysis and 0.08 0.14 gg/L before production resinned (Selden et al. 1993). Mild skin and mucous membrane irritation were reported in the exposed group, suggesting that exposure may have been through either the inhalation or dermal routes of exposure. 

Blood is the transport medium of the body. Plasma, which accounts for approximately 60% of the total volume, carries a wide range of small and medium-sized metabolites some are simply dissolved in solution (93% of the plasma is water), others are carried by specific carrier proteins. The chemical composition of the plasma is complex and reflects the chemical composition inside cells, which is why blood tests are so commonly used in diagnosis to see the biochemical events occurring in tissues. The formed cellular elements of the blood perform several functions defence against blood loss from bleeding (platelets, also called thrombocytes), defence against infection and immune surveillance (white cells, leucocytes), and gas transport and pH buffering (red cells, erythrocytes). 

Platelets (also called thrombocytes), the smallest of the formed elements of the blood, are formed by fragmentation of megakaryocytes. Each megakaryocyte (mega = big , karyo = nucleus ) can produce approximately 3000 individual platelets and a total of about 2 x 1011 platelets are formed each day. 

In addition to erythrocytes, blood contains white blood cells, called leukocytes, of several types, and platelets, also called thrombocytes, which control blood clotting. Hematopoiesis (from the Greek, haimo, for blood, and poiein for to make ) is the process by which the elements of the blood are formed. The marrow of bone contains so-called stem cells which are immature predecessors of these three types of blood cells. Chemicals that are toxic to bone marrow can lead to anemia (decreased levels of erythrocytes), leukopenia (decreased numbers of leukocytes), or thrombocytopenia. Pancytopenia, a severe form of poisoning, refers to the reduction in circulatory levels of all three elements of the blood. One or more of these conditions can result from sufficiently intense exposure to chemicals such as benzene, arsenic, the explosive trinitrotoluene (TNT), gold, certain drugs, and ionizing radiation. Health consequences can range... 

Medicinal thrombocytopenia can emerge under the use of different medicines, including interferon. The main mechanism of medicinal thrombocytopenia pathogenesis is assisted by the destruction of thrombocytes by the complement which is activated during antibody preparation. On withdrawal, the content of thrombocytes in blood is normalized. The formation of antibodies to thrombocytes in patients with viral hepatitis C occurs due to the destruction of membrane glycoproteins by the viruses. 

Variant 2. The patients with small thrombocyte number in the blood (not less than 100 x 10 in liter) are recommended, during the antiviral therapy, medium doses of Grinization (Grin Mix — 15 mL per day. Grin Pro — 10 capsules per day, or 7 g of the powder per day). With the tendency of decreasing thrombocyte number, the dose should be diminished to the prophylactic level. 

Variant 3. The patients with a serious decrease of thrombocytes number in blood (less than 90 x 10 in 1 L) before antiviral therapy application during 14 days are recommended to use high doses of Grinization (Grin Mix — from 25 to 33 mL, Grin Pro — from 12 to 16 g per day), till the number of thrombocytes is increased up to 100 x 10 in liters or more. For the period of antiviral therapy application, Grinization is recommended in medium doses. While the thrombocyte number is stabilized, the Grinization doses should be diminished up to the prophylactic ones. 

Massive use of diuretics entails a hazard of adverse effects (A) (1) the decrease in blood volume can lead to hypotension and collapse (2) blood viscosity rises due to the increase in eryth-ro- and thrombocyte concentration, bringing an increased risk of intravascular coagulation or thrombosis. 

The solid elements in the blood are the erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets). 

Following injury to blood vessels, hemostasis ensures that blood loss is minimized. Initially, thrombocyte activation leads to contraction of the injured vessel and the formation of a loose clot consisting of thrombocytes (hemostasis). Slightly later, the action of the enzyme thrombin leads to the formation and deposition in the thrombus of polymeric fibrin (coagulation, blood clotting). The coagulation process is discussed here in detail. 

Dipyridamole increases coronary blood circulation, increases oxygen flow to the myocardium, potentiates adenosine activity, and impedes its metabolization. It inhibits aggregation of thrombocytes, blocks phosphodiesterase, increases microcirculation, and inhibits the formation of thrombocytes. 

Thrombocytes Initiate blood clotting 3X10 1 week... 

IgG or IgM antibodies direct the immune response toward the antigen located on a cell (e.g., a red blood cell or thrombocyte). Macrophages, NK cells, and neutrophils are recruited by the antibodies to the site of the antigen on the cell surface and destroy the cell by phagocytosis or lysis. Additionally, complement activation will damage the cell (Fig. 6.32). The result, for example, where red cells are the targets is hemolytic anemia. 

The thromboxanes have a six-membered ring containing an ether. They are produced by platelets (also called thrombocytes) and act in the formation of blood clots and the reduction of blood flow to the site of a clot. The nonsteroidal antiinflammatory drugs (NSAIDs)— aspirin, ibuprofen, and meclofenamate, for example— were shown by John Vane to inhibit the enzyme prostaglandin H2 synthase (also called cyclooxygenase or COX), which catalyzes an early step in the pathway from arachidonate to prostaglandins and thromboxanes (Fig. 10-18 see also Box 21-2). 

Thromboxane synthase, present in blood platelets (thrombocytes), converts PGH2 to thromboxane A2, from which other thromboxanes are derived (Fig. 21-15a). Thromboxanes induce constriction of blood vessels and platelet aggregation, early steps in blood clotting. Low doses of aspirin, taken regularly, reduce the probability of heart attacks and strokes by reducing thromboxane production. ... 

AUTOMATED INSTRUMENTATION HEMATOLOGY. Hematology analyzers provide information about blood cells and their constituents. The three basic blood cell types are erythrocytes or red blood cells, leukocytes or white blood cells, and thrombocytes or platelets. Hemoglobin is die principal nonaqueous component of red blood cells. Its physiological importance gives it the status of a primary hematological constituent. 

Small blood constituents formed from APUD cells which are involved in blood clotting. Platelets are also called thrombocytes. 

Hematological Effects. Low serum potassium level was observed in a 22- year-old factory worker accidentally exposed by acute inhalation to barium carbonate powder (Shankle and Keane 1988). Altered hematological parameters were observed in rats following inhalation for an intermediate exposure period to 3.6 mg barium/m as barium carbonate dust (Tarasenko et al. 1977). Reported changes included decreased blood hemoglobin, decreased thrombocyte count, decreased blood glucose, decreased albumin, increased leukocyte count, and increased blood phosphorus. 

Normal values for total blood volume vary depending on the methods used for its determination and the basis of reference (sex, age, weight, surface area). In a healthy adult or normal body habitus, the circulating blood comprises 6-8% of the body weight, or 63-80 mL/kg. Blood consists of cellular elements suspended in a solution containing a host of proteins and low molecular weight substances. There are three types of cells in blood the red cells (erythrocytes), the white cells (leukocytes), and platelets (thrombocytes). Only the white cells possess... 

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