ANTITOXIN

Antitoxin are antibodies found in the gamma globulin in blood protein. They are formed to inactivate poisons, or toxins, caused by infecting bacteria or other living organism. In tetanus, for example, tetanus antitoxin can neutralized toxin that causes muscle spasm and convulsions before it is bound to nerve cells.

Antitoxins can be obtained from the blood of a human who has survived the disease; from the blood of animals (usually horses) that have been injected with either the bacterium or the toxin; and from the injection of toxoid , a bacterial culture that has been rendered noninfective but that retains enough characteristic to be antigenic, or capable of stimulating antibody production is too slow after toxoid use, and an antitoxin is injected, as in tetanus or botulism. Injections of toxoids that prevent diphtheria and tetanus are usually given in the early years of life, with ‘boosters’ at appropriate intervals, thus avoiding the need for antitoxin.

Related articles:

Vaccination

Function of Immune System

Blood Diseases

Anemia
Anemia is a deficiency of hemoglobin in the blood, generally caused by blood loss; abnormal destruction of the red cells, as in Sickle-cell disease; or inadequate red cells formation by the bone marrow, as in a plasmatic anemia and pernicious anemia. Anemia also occurs as a result of methermoglobinemia, a disorder in which methemoglobin, a nonfunctional form of hemoglobin, is present in the red cells.

In some persons, the concentration of red cells and of hemoglobin in the blood may be abnormally increased, rather than decreased, resulting in polycythemia. This is usually caused by an increased production of red cells, but in some persons it may be caused by a decreased volume of plasma.

Neutropenia
Deficiency of circulating granulocytes with poor resistance to infection, may occur in many diseases. One common cause is the use of X rays and toxic drugs to treat many malignant diseases.

LeukemiaA great increase in abnormal leukecytes or white blood cell may occur for unknown reasons, resulting in the diseases known as the leukemias. These range from the chronic lymphocytic leukemia, in which a person may live form many years, to devastating acute leukemia, often causing death within month.

Thrombocytopenia
The number of platelets can severely decrease, with danger of bleeding. Perhaps the most common cause of platelet deficiency, or thrombocytopenia, is an autoimmune disease related to autoimmune hemolytic anemia. The difference is that, in these cases, the body produces antibodies that attack only the platelets.

HemophiliaDeficiencies of one or more of the plasma coagulation factors may also cause abnormal bleeding. The existence of many of the clothing factors was recognized only when persons were found who lacked such a factor. The best known such bleeding disorder is Hemophilia.

Thromboembolic DiseasesAbnormal clotting in the blood vessels, known as thromboembolic disease, may be caused by an excess of one or more of the plasma clothing factors, or at times to a deficiency of one of the fibrinolytic factors. This group of disorders is one of the most common causes of death in middle aged and elderly persons.

Blood Clotting

The clotting process is initiated by a protein called tissue factor, which is bound to the membranes of most cells outside the bloodstream. Blood coming into contact with these membranes sets off a sequence of reactions involving various blood proteins called factors. Thus, a molecule of factor VII coming into contact with tissue factor converts to an active form that in turn converts ten molecules of factor X into thromboplastin, with the help of calcium ions. Thromboplastin in turn binds to factor Va, which then binds to the protein prothrombin to form two million molecules of the clotting enzyme thrombin. Thrombin acts as a catalyst to convert fibrinogen to billions of molecules of the insoluble protein fibrin, the basis of the final clot. The clot is made firm by factor XIII reinforced by blood platelets.

Because minor injuries often occur, the clotting process is almost constantly taking place somewhere in the body. It must be terminated quickly, however or blood would clot everywhere and death would ensue. To prevent this form happening, plasma protein known as fibrinolysins, or plasmins, dissolve old clots in the bloodstream.

Red Blood Cells

Red blood cells, or erythrocytes, as a part of Blood group are tiny, round, biconcave disks averaging7.5 microns (0.003 in) in diameter. A normal 76.5 kg (170-lb) main has about 5 l (5.3 qt) of blood, containing more than 25 trillion red cells. Because the normal life span of red cells is only about 120 days, more than 200 billion cells are normally destroyed each day by the spleen and must be replaced. Red cells are made in the bone marrow.

The main function of the red blood cells is to transport oxygen from the lungs to the tissue. Oxidations of various food substances to supply most of the energy requirements of the body results in carbon dioxide, one of the chief waste products, and red blood cells carry it to the lungs for release and to pick up more oxygen.

The substance in the red blood cells that is largely responsible for their ability to carry oxygen and carbon dioxide is hemoglobin, the material that gives the cells their red color. Produced in the bone marrow and broken down in the spleen, it is a protein complex comprising many linked amino acids, and occupies almost the entire volume of a red blood cell. Essential to its structure and function is iron.

Blood is a tissue comprising two main components; a plasma fluid (A) and freely moving blood cells, which are white (B) or red (C). Plasma, comprising 90% water, does not have cells but contains proteins and salts that buffer substances traveling through the blood vessels. White blood cells include three types of granulocytes, which are basophils (1), eosinophils (2), and neutrophils (3); small ad large lymphocytes (4, 5) and monocytes (6). White blood cells defend the body against infection by engulfing the invading bacteria and by healing wounds. Platelets (7) are cell fragments that catalyze blood cloting. Red blood cells (8), which have no nuclei, are shaped like indented disks. These cells contain hemoglobin, protein that transports oxygen to body tissues.