BLOOD DISEASES

Te Awamutu Courier, Volume 53, Issue 3822, 16 October 1936, Page 2

BLOOD DISEASES

DESTRUCTION OF RED BLOOD CELLS. The red celsl of our blood contain a substance called haemoglibin, which is the vehicle by which oxygen is carried from the lungs to the various celsl of the body. In adults the red cells are continually being made in the red marrow of the bones. They are celsl highly specialised for their particular purpose; during their maturation the nucleus, an essential feature during the functional life of nearly all other cells, disappears. If owing to loss of red cells in the circulating blood, new ones are hurried into the circulation of an immature stage the nuclei may be seen in various stages of disappearance. The life of a red cell in'the circulating blood is short—a period of only a few weeks. The maemoglobin escapes from tlie effete red cells, but is not wasted. Most of it is converted into bile pigment. At one time it was thought that the celsl of the liver were alone responsible for the conversion of the red coloured haemoglobin into the yellow and gren pigment of the bile. It is now known that the most important site of this change is in certain celsl lining blood channels, and that the chief cells of the liver give only the finishing touches to the final product. If for any reason an unusual numl>er of red cells is destroyed in the circulation, then an increase of the haemoglobin in the fluid portion of the blood, the plasma, can be recognised, and this increased supply may lead to an extra amount of bile pigment being produced. EXCESSIVE DESTRUCTION. The setting free of haemoglobin in small amounts from old red cells is a normal event in our circulating blood. The loss in red cells is at once made good. In a number of very different circumstances an excessive destruction of many circulating red cells may take place. These are not old ceils, no longer capable of continuing their work efficiently, but celsl still functioning well. In the recent cases in Adelaide two seamen from an overseas vessel became severely ill, and on admission to hospital the most important feature revealed was that in some way a very large number of the circulating red cells had undergone dissolution with the escape of their haemoglobin, a condition known as haemoglobinaemia. The amount of haemoglobin had been so great that large quantities had been excreted by the kidneys. This is not the place to discuss the possible cause of the condition in these patients. It is, however, of interest to consider the various ways in which a destruction of many circulating red cells may occur. Parasites may grow in the erd cells and as they mature may cause the red cels to break up. In the northern parts of Australia tick fever in cattle is due to a small animal parasite, piroplasma, which develops in the red cells. The haemoglobin liberated as a result of this parasitic infestation escapes into the urine; hence the name “red water,” by which this disease is known. Sometimes such a large quantity of bile pigment is made i'rim this haemoglobin that jaundice results. Malarial parasites in man destroy the red cells in which they grow. Most of the haemoglobin, however, is utilised in the red cells by the growing parasites, though some is liberated and occasionally jaundice occurs. BLOOD TRANSFUSION. If, during a blood transfusion in man, tlie red cells of the donor belong to an incompatible blood group, they will become aggregated into little clumps by the plasma of the recipient, and will later undergo haemolysis. One of the chief dangers of this is that, as in blackwater fever, the colouring matter may be deposited in tne kidneys, and may prevent their functioning. Before a transfusion is made, tests are carried out to see that the blood of the donor belongs to a correct blood group. One of the bacteria responsible for gas gangrene, an organism commonly spoken of Bacillus Welchii, is capable of producing a toxin which will cause dissolution of red cells. Occasionally, in puerperal cases, this organism may grow in dead tissue devoid of free oxygen, a necessary condition for its multiplication. The haemolytic toxin may escape into the blood stream and cause such a rapid destruction of red cells that death may occur in 24 hours.

Other disease producing bacteria teria may also cause haemolysis. One of the toadstools, known as Amanitaphalloides, contains a haemolytic poison. This haemolytic agent is readily destroyed by heat and by the digestive ferments, but may operate if the supposed mushrooms are insufficiently cooked.

Cases of poisoning in man however, seem usually due to another poison, amanita toxin, which resists the action of heat. Various chemical substances in gaseous farm or taken by the mouth may cause haemolysis, usually associated with other changes in tlie blood. Among these may be mentioned nitro-benzine, potassium chlorate, arseniureteed hydrogen, and even quinine. The venoms of some snakes are intensely haemolytic, the destruc-

tive agent in such cases being introduced subcutaneously. REMARKABLE FROM. A remarkable form of haemolysis is seen in a rare condition known as Paroxysmal Haemoglobinuria; in this condition no change occurs in the blood at the ordinary temperature of the body, but if certain parts are chilled, the lower temperature enables certain changes to take place, by which many red cells are destroyed. Even washing the hands in cold water is said to give rise to an attack in a susceptible person. If distilled water is added to blood, tlie colouring matter will be set free. The red cells in the circulating blodd live in a medium with a content of about 0.8 per cent of sales. This concentration of salts can be reduced to some extent before the red cells will break up. As the amount is reduced some cells will break up before others until, in normal persons, a stage is reached when all undergo haemolysis. In certain individuals in certain families, the red cells undergo haemolysis in concentrations of common salt which would not destroy the red cells of ordinary people. The dis solved colouring matter may give rise to a jaundiced tint. Tlie above short review shows how complicated are the reactions associated with the colouring matter of tlie blood, and how varied are the conditions that may give rise to the escape of haemoglobin from the circulating red corpuscles.