Anemia
Anemia is a disorder in which the blood has less hemoglobin or fewer red cells than normal. With less hemoglobin, the blood carries less oxygen to the body's cells, which causes weakness, fatigue, and paleness in the anemic person. If hemoglobin levels drop low enough, the patient could die. Anemia can be caused by a diet deficient in iron or by heavy bleeding; these anemias are relatively simple to treat with supplemental iron and iron-rich foods. Anemia can also result from a failure of red cells to develop normally, from excessive destruction of red cells in the blood, and from a failure of the bone marrow to produce red cells. These anemias are more difficult to treat.
The first recognized anemia was chlorosis, or "the green sickness," common in girls until the early 1900s. Although the condition was recognized as early as the 1500s, the sickness itself was not understood until the 1800s. French physician Gabriel Andral is credited with introducing the term anemia around 1829
The first thoroughly studied anemia was pernicious anemia, so called because it invariably led to death. In a patient with pernicious anemia, the red blood cells fail to develop normally, and the steady decline of red blood corpuscles eventually leads to death.
English physician Thomas Addison (1793-1860) gave the first complete description of the disease--"a remarkable form of general anemia"--in 1849. Addison noted the typical symptoms, including increasing weakness and paleness of the patient, accompanied by obesity rather than weight loss. Addison expanded his description in 1855 to describe a hormone deficiency disorder, later called Addison's disease, caused by a malfunction of the adrenal glands. He distinguished between Addison's, characterized by progressive anemia caused by low blood volume, and the earlier-noted pernicious anemia (sometimes also called Addison's anemia), the cause of which remained unknown. German physician Anton Biermer (1827-1892) also described pernicious anemia in 1868 and 1872, reporting it as a newly discovered disease.
The first step toward curing pernicious anemia was taken by the American pathologist George Whipple (1878-1976). Working at the University of California, San Francisco, from 1917 to 1918 and at the University of Rochester (New York) from 1923 to 1925, Whipple induced anemia in dogs by bleeding them and experimented with various kinds of diets to see what was most effective in regenerating the dogs' hemoglobin. Liver was the answer, and Whipple further found that iron stimulated hemoglobin formation.
Whipple's study was continued by George Richards Minot (1885-1950), a Harvard-educated physician serving at two well-known Boston hospitals, Massachusetts General and Peter Bent Brigham. Suspecting that pernicious anemia might be due to a dietary deficiency, Minot in 1924 began prescribing liver to some of his private patients. When that proved effective, Minot and fellow physician William P. Murphy put hospital patients with pernicious anemia on a liver diet. By 1926, forty-five patients were on the diet, showing obvious and often rapid improvement in their previously life-threatening condition.
Worldwide use of the Minot-Murphy liver diet proved its effectiveness in treating pernicious anemia, saving thousands of lives each year. The diet, however, had a major drawback: each patient had to eat half a pound of liver every day. This problem was overcome when Edwin Cohn (1892-1953), a Harvard physical chemist, developed an extremely potent liver extract in 1928 that could be eaten in small amounts or injected.
A contemporary of Minot's, Harvard physician William Castle (1867-1962), noted that patients who lost their stomach to cancer often developed pernicious anemia, even when fed liver. In 1929 Castle suggested that normal gastric (stomach) juice must contain an "intrinsic factor" that allowed absorption into the body of an unknown "extrinsic factor" in liver. Soon, a hog-stomach extract became available that contained the missing but still unidentified factor. Finally, in 1948, two groups of researchers--a team working in an American laboratory headed by Karl Folkers and a team in England--both announced that they had isolated the liver factor, a ruby-red crystalline substance named 12vitamin B12. The liver fed to Minot and Murphy's patients had been effective because it was very high in B12. Today, patients with pernicious anemia receive monthly injections of vitamin B12 and enjoy a normal life expectancy.
Another deadly form of red blood cell disease is sickle-cell anemia. American physician James B. Herrick (1861-1954) gave the first clear description of the condition in 1910. In this inherited disorder, which afflicts 1 in 625 African Americans and often kills children, a mutated gene produces abnormal hemoglobin that deforms the red blood cells into a sickle shape. The abnormal cells slow down and decrease blood circulation. American chemist Linus Pauling showed in 1949 that a defective gene in a protein molecule caused the abnormal hemoglobin. In 1960, Max Perutz worked out the precise atomic structure of hemoglobin, which holds promise for a better understanding and treatment of sickle-cell anemia.
Other anemias discovered by medical researchers over the years include: anemia of pregnancy, first accurately described by German physician Hermann Nasse in 1836; chronic leukemia, a proliferation of white blood cells, described by Rudolf Virchow in 1845; aplastic anemia, caused by bone marrow damage or destruction, differentiated by German bacteriologist Paul Ehrlich in 1888; Fanconi anemia, an inherited anemia named after Swiss pediatrician, Guido Fanconi, and which leads to aplastic anemia; chronic infectious anemia, detailed by Adolf Edelmann, an Austrian physician, in 1925; acute hemolytic anemia, characterized by rapid destruction of red blood cells, described by American pathologist Max Lederer in 1925; and thalassemia, an inherited anemia found mostly in people of Mediterranean origin, reported by American physician Thomas B. Cooley (1871-1945) in 1927.
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