Gastritis

Gastritis, acute or chronic inflammation of the mucosal lining of the stomach. The ailment was first described in 1833 by the American military surgeon William Beaumont, who was able to study the mucosa of a man who had suffered a gunshot wound in the abdomen. The wound healed with an opening in the stomach wall, through which Beaumont was able to observe the patient's digestive process. In gastritis the inflammation may be marked by the erosion of surface cells of the mucosa, formation of granular nodules, and hemorrhage. In chronic gastritis, there is a growth of fibrous tissue on the lining. Weight loss and delayed emptying of the contents of the stomach may accompany the disease. Gastritis may be caused by excessive consumption of alcohol, abnormal secretion of hydrochloric acid in the gastric juices, and various infections ranging from syphilis and tuberculosis to fungus. Psychological stress may also be involved in the development of gastritis.

Gangrene

Gangrene, mass death or necrosis of individual cells or tissues of a living organism. The immediate physiological cause of gangrene is blockage of arterial blood supply. Among the symptoms of gangrene are loss of sensation and function. The affected part, usually a limb, becomes cold, turns progressively darker in color, and finally undergoes decomposition. Gangrene may take two forms, dry gangrene or moist gangrene.

Dry, or chronic, gangrene occurs when the arteries are blocked gradually and the tissues are bloodless. It may be a result of arteriosclerosis (see Artery). It may also follow frostbite, injury, or the vascular collapse that often accompanies diabetes.

If the dead, bloodless tissue becomes infected by the anaerobic bacterium Clostridium, the condition is called moist, or acute, gangrene. It is also known as gas gangrene because of its putrid-smelling gaseous discharge. The victim's temperature rises sharply, and he or she suffers great pain, acute anemia, and prostration. Moist gangrene may follow contamination of a wound with dirt or other infected matter. It once occurred frequently with war wounds and still occurs among diabetics and after abortions performed under unsanitary conditions. Moist gangrene is fatal unless treated with antibiotics. In severe cases amputation is necessary.

Blood Transfusion

Blood Transfusion, in medicine, the procedure of introducing the blood of a donor or blood predonated by the recipient (autologous transfusion) into the bloodstream. It is a highly effective form of therapy and has saved the lives of incalculable numbers of people suffering from shock, hemorrhage, or blood diseases. Blood transfusion is employed routinely in cases of surgery, trauma, gastrointestinal bleeding, and in childbirths that involve great loss of blood.

Transfusions still tend to cause the development of sensitivity and increase the possibility that the recipient will react to any later transfusions. Transmission of viral hepatitis was a major risk until a method of screening blood for infectivity was developed in the 1960s; some other forms of hepatitis, however, are not detected by this test. In 1985 a test was introduced that screens donated blood for an antigen associated with AIDS, or acquired immunodeficiency syndrome.

Angina Pectoris

Angina Pectoris, symptom of reduced oxygen supply to the heart muscle, usually caused by narrowing or obstruction of the coronary artery. It is marked by a viselike squeezing sensation beneath the breastbone. Pain may radiate from the front of the chest, often into the arm. The attacks usually last several minutes. They may be caused by emotional stress but are more likely to result from physical activities that require an increased supply of blood to the heart. The disease occurs most commonly in middle-aged and older people, particularly those who suffer from arteriosclerosis. Relief is obtained by rest and relaxation. Patients can be treated with drugs that relax and dilate blood vessels or that slow the heart, and surgery can be performed to improve coronary circulation. The attacks themselves cause no damage.

Bone Disease

A variety of diseases affect bones. One of the most common bone diseases is osteoporosis, which is characterized by a thinning of bone tissue, causing bones to become weak, brittle, and prone to fractures. Many factors can cause osteoporosis, including menopause, lack of exercise, low calcium intake, smoking, use of steroid drugs, and excessive consumption of alcohol.

Dietary deficiencies of calcium, phosphorus, and vitamin D cause rickets, a disease characterized by abnormal bone formation and skeletal deformities. Rickets is most common in children. Dietary deficiencies of these nutrients in adults-or metabolic disorders that cause poor absorption of the nutrients-can result in an abnormal softening of bone, a condition called osteomalacia.

Infections of bones called osteomyelitis usually are caused by bacteria, especially Staphylococcus, which enters the body through open wounds and may destroy bone tissues. Tumors, or abnormal growths, occur in bone tissue, though most are benign. Cancerous tumors can be caused by excessive radiation; many radioactive substances have an affinity for bone, particularly the marrow, and are readily stored there. Most cancerous tumors in bones, however, are tumors that spread from cancer in other parts of the body. Cancers that arise in bone, cartilage, and other connective tissues are called sarcomas.