Drugs Classification

Haemopoietic system and blood

Haemopoietic system consists of two main parts - the bone marrow and peripheral blood. The bone marrow is located in the bones, mainly in the flat bones - the sternum, ribs, ilium. Here takes place a very difficult process of formation of all blood elements.

All blood cells originate from a single stem cell that multiplies in the bone marrow, and the development goes in four directions - formation of red blood cells (erythropoiesis), leukocytes (myelopoiesis), lymphocytes (lymphopoiesis) and platelets (thrombocytopoiesis). Only mature cells capable of performing well-defined functions enter the peripheral blood.

What are these mature cells and what functions they perform in the body?

Erythrocytes (often called red blood cells) make up the vast majority of peripheral blood cells. Virtually the entire cell made up of hemoglobin, the substance by which erythrocyte performs its primary task - to bring oxygen into every cell of the body and then to carry away carbon dioxide. Passing through the lungs, red blood cells give way carbon dioxide and receive oxygen. For normal development of red blood cells, the bone marrow must have sufficient iron and vitamin B12.

Leucocytes, or white blood cells are a heterogeneous group of blood cells. They are divided into neutrophils, eosinophils and basophils. The main function of neutrophils is protection through implementation of phagocytosis: they absorb microorganisms and foreign bodies. Eosinophils play a central role in protecting the body against parasitic infections. They are actively involved in the mechanism of development of some diseases bronchial asthma, allergic skin reactions. The importance of basophils in normal conditions is not known. Their functions are associated mainly with allergic reactions.

Lymphocytes are a diverse group of cells. By their origin and functions, lymphocytes are divided into 2 groups: T-lymphocytes and B-lymphocytes. T-lymphocyte include memory cells that recognize foreign proteins and give the signal for the beginning of the protective (immune) response; T-helpers that stimulate deployment of immunological processes, such as B cells; T-suppressors that inhibit maturation of effector cells, and T-killers- cells-effectors of cellular immunity. B-lymphocytes are differentiated into plasma cells which produce antibodies effecting humoral immunity.

Thrombocytes are blood platelets, the primary function of which is participation in the process of blood clotting. There is evidence that platelets play a role also in the metabolism of cells of blood vessels.

Very often, the lesions of the hemopoietic system are characterized by general non-specific symptoms. Patients complain on fever, weakness, malaise, decreased performance, increased fatigue. Particular attention should attract complaints of shortness of breath and palpitations in the absence of any sign of violation of the cardiovascular and respiratory systems.

A number of patients experience more characteristic symptoms of the hemopoietic system lesions: taste perversions, burning sensation in the tongue, sometimes in combination with swallowing disorders, sensitivity violation, paralysis, itching, lymph-node hyperplasia, hemorrhage in the skin and joints, bleeding gums, nose, intestine and uterus.

In taste perversion, patients experience a strong, sometimes irresistible urge to eat products which are usually not used as food - chalk, clay, vinegar, raw cereals, etc. or they begin to like specific odors - gasoline, nitrocellulose enamel. Such symptoms are typical for patients with iron deficiency anemia and latent iron deficiency.

Burning sensation in the tongue, complaints of violations of sensitivity and sometimes paralysis are characteristic to patients with B12-deficiency anemia and are explained by onset of tongue inflammation and disorders of the peripheral nervous system. Unpleasant feelings in the tongue combined with swallowing disorders may also be in iron deficiency anemia.

Increased bleeding (hemorrhagic phenomena) indicate irregularities in the blood coagulation system - primary or secondary, complicating diseases of other organs and systems. Swollen lymph nodes are a manifestation of lymphoproliferative changes.

Itching is a frequent symptom of skin diseases, however, if there is no skin rash and skin color changes, it could be a manifestation of a hematopoietic system disorder, in particular Hodgkin's lymphoma. This assumption is justified if itching is combined with fever and night sweats.

Characteristic signs of the hematopoietic system lesions are changes in skin color, bleeding, diarrhea and bleeding gums, bleeding in the joints, changes in the palatine tonsils and in the mucosa of the cheeks, tongue changes, and lymph nodes enlargement.

Patients with blood diseases often have enlarged liver and spleen.

In the therapy of haemopoietic system disorders mainly are used medicinal agents that regulate hematopoiesis, stimulate or inhibit the formation of blood cells (erythrocytes and leukocytes) and / or stimulate the formation of hemoglobin. There are two main groups of medicines for hematopoiesis regulation:

In leucopenia caused by X-ray and radiotherapy, chemotherapy of malignant neoplasms, as well as in leucopenia accompanying various diseases, are used drugs for leukopoiesis stimulation. For this purpose, specialists use colony-stimulating factors of the human granulocytes, e.g. Lenograstim that is a recombinant human granulocyte colony stimulating factor, similar to the action of the corresponding endogenous substance. Represents glycosylated protein. It stimulates the proliferation and differentiation of precursor cells of neutrophilic series, causes an increase in the number of neutrophils in peripheral blood, increases functional activity of neutrophils.

For stimulation of erythropoiesis in anemias is used recombinant human erythropoietin sold under brand names Epogen, Epotin, Procrit, Eprex etc. It represents a purified glycoprotein that affects cell division and differentiation of precursor cells. Epoetin alfa is produced by mammalian cells with built-in gene encoding the human erythropoietin synthesis. After administration of this drug, the quantity of red blood cells, reticulocytes, hemoglobin level and rate of iron absorption increase. Eprex has a pronounced effect on anemia caused by chronic kidney disease.

For the treatment of anemia, depending on their etiology, are used various antianemic drugs affecting erythropoiesis. For example, for the treatment of iron deficiency anemia are used iron supplements (iron gluconate, sulfate, furamat, Ferrum Lek for parenteral administration), and ascorbic acid that enhances iron absorption, drugs containing cobalt that promotes the absorption of iron. For the treatment of B12-deficiency anemia is used vitamin B12 (cyanocobalamin), for the treatment of anemia caused by deficiency of folic acid - folic acid.

In various areas of medicine used drugs decreasing (anticoagulant) or increasing (antihemorrhagic) blood clotting.

Anticoagulant and antithrombotic drugs. To prevent thrombus formation and development of thromboembolism often occurred after surgical intervention, myocardial infarction, as well as other diseases, are used substances that inhibit blood clotting. Anticoagulant drugs include anticoagulants, fibrinolytic preparations and antiplatelet drugs.

Anticoagulants are mainly used to prevent the formation of fibrin strands and thrombus formation. They promote cessation of growth of blood clots that have already arisen. They are divided into 2 groups: anticoagulants of direct and indirect action. Direct anticoagulants include various natural anticoagulant factors - heparin and antithrombin III. Indirect anticoagulants include acenocoumarol (Syncumar), phenindione, etc. All of them are antagonists of vitamin K, necessary for the formation of prothrombin in the liver.

Fibrinolytic agents cause destruction of the formed fibrin strands, and they contribute mostly to the resorption of fresh blood clots.

Antiplatelet agents inhibit aggregation of platelets and red blood cells, reduces their ability to stick to the endothelium of blood vessels. A pronounced antiplatelet effect posses non-steroid anti-inflammatory drugs, among which is widely used acetylsalicylic acid.

Antihemorrhagic and haemostatic drugs

Bleeding associated with increased fibrinolytic activity of blood, is relieved by inhibitors of fibrinolysis.

In the hemorrhagic syndrome with hypoprothrombinemia caused by, for example, abnormal liver function, are used vitamin K preparations. Ethamsylate is used to activate thromboplastin formation.

In the shortage of blood clotting factors (eg, hemophilia) is coagulation factor VIII and von Willebrand factor in hemophilia A and human coagulation factor IX in hemophilia B.

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