Kids Research Express

Lupus Erythematosus, chronic autoimmune disease in which the immune system treats the body’s own tissue as a foreign substance and produces antibodies to fight it. The damage caused by these antibodies may produce symptoms such as a characteristic butterfly-shaped rash on the face, headache, fatigue, arthritic joint disease, heart damage, shortness of breath, and impaired kidney function. Commonly known as lupus, the disease follows an irregular course of remissions and flare-ups, and may often be incapacitating Diagnosis of lupus is difficult and can take years because symptoms are intermittent or may mimic other disorders. Diagnosis begins with a complete medical history, a physical examination, blood tests, and other studies that may be necessitated by the patient’s symptoms. The physician, normally a rheumatologist (an expert on musculoskeletal and immune system conditions) must consider and rule out other disorders such as chronic fatigue syndrome or mononucleosis before confirm...

Transient Ischemic Attack (TIA), medical term for a ministroke, a sudden loss of function in one region of the brain. Symptoms may include double vision or temporary loss of vision, speech difficulties, vomiting, loss of sensation and movement on one side of the body, dizziness, unsteadiness, and loss of memory. Loss of consciousness is rare. Symptoms usually reach a peak within seconds and last for minutes or hours. Recovery is complete, but TIAs tend to recur. A TIA is caused by the obstruction of small blood vessels by tiny blood clots or, less often, by reduced blood supply to the brain associated with diseases of the heart or blood vessels, such as narrowing of the arteries due to atherosclerosis. Aspirin, because of its anticlotting properties, may reduce the risk of TIAs in some patients. Other cases may be helped by an operation known as carotid artery endarterectomy, used to clear blockage of the carotid artery in the neck.

Yellow Fever, noncontagious, infectious disease, caused by a virus, and characterized in severe cases by high fever and jaundice. Originally yellow fever was believed to be exclusively a disease of humans, but research has revealed that it also affects monkeys and other animals. It is believed that diseased monkeys of Africa and tropical America are the primary source of infection and that carrier mosquitoes transmit the infection to humans. This type of the disease, which occurs only sporadically in human beings, is known as jungle yellow fever. If infected individuals move into a populated area, they may be bitten by a semidomestic species of mosquito, such as Aëdes aegypti, which lives close to human habitations. These feed on the blood of humans and are the chief transmitting agents in epidemics of urban yellow fever.

Whooping Cough, also known as pertussis, common name applied to an acute, infectious disease of the respiratory tract, caused by the bacillus Bordetella pertussis. The disease is characterized in its late stages by a deep cough ending in a peculiar high-pitched whooping sound. Whooping cough occurs worldwide, periodically in epidemics. Infection with pertussis usually occurs by inhaling droplets sprayed into the air during coughing or sneezing spells by an infected person. Once inside the respiratory tract, pertussis bacteria produce toxins (poisonous chemicals) that interfere with the respiratory tract’s ability to eliminate microbial infections. Pertussis bacteria also produce chemicals that cause inflammation of the lining of the respiratory tract. The disease begins with a runny nose, a harsh cough, and a slight fever. The characteristic whoop develops one to two weeks later. Coughing spells, which usually occur at night and often end in vomiting, can continue to occur for four wee...

This vitamin is necessary mainly for the coagulation of blood. It aids in forming prothrombin, an enzyme needed to produce fibrin for blood clotting. The richest sources of vitamin K are alfalfa and fish livers, which are used in making concentrated preparations of this vitamin. Dietary sources include all leafy green vegetables, egg yolks, soybean oil, and liver. For a healthy adult, a normal diet and bacterial synthesis in the bowels usually are sufficient to supply the body with vitamin K and prothrombin. Digestive disturbances may lead to defective absorption of vitamin K and hence to mild disorders in blood clotting.

The role of vitamin E in the human body is known to be an essential nutrient in more than 20 vertebrate species. The vitamin plays some role in forming red blood cells and muscle and other tissues and in preventing the oxidation of vitamin A and fats. It is found in vegetable oils, wheat germ, liver, and leafy green vegetables. Vitamin E is popularly advocated for a wide range of diseases, but no substantial evidence has been found to back these claims. Although vitamin E is stored in the body, overdoses appear to have lower toxic effects than do overdoses of other fat-soluble vitamins.

This vitamin is necessary for normal bone formation and for retention of calcium and phosphorus in the body. It also protects the teeth and bones against the effects of low calcium intake by making more effective use of calcium and phosphorus. Also called the sunshine vitamin, vitamin D is obtained from egg yolk, liver, tuna, and vitamin-D fortified milk. It is also manufactured in the body when sterols, which are commonly found in many foods, migrate to the skin and become irradiated. Vitamin D deficiency, or rickets, occurs only rarely in tropical climates where sunlight is abundant, but it was once common among children of other areas before the use of vitamin D-fortified milk. Rickets is characterized by deformities of the rib cage and skull and by bowlegs, due to failure of the body to absorb calcium and phosphorus. Because vitamin D is fat-soluble and stored in the body, excessive consumption can cause vitamin poisoning, kidney damage, lethargy, and loss of appetite.

Vitamin C or ascorbic acid, a well-known vitamin is important in the formation and maintenance of collagen, the protein that supports many body structures and plays a major role in the formation of bones and teeth. It also enhances the absorption of iron from foods of vegetable origin. Scurvy is the classic manifestation of severe ascorbic acid deficiency. Its symptoms are due to loss of the cementing action of collagen and include hemorrhages, loosening of teeth, and cellular changes in the long bones of children. Assertions that massive doses of ascorbic acid prevent colds and influenza have not been borne out by carefully controlled experiments. In other experiments, however, ascorbic acid has been shown to prevent the formation of nitrosamines—compounds found to produce tumors in laboratory animals and possibly also in humans. Although unused ascorbic acid is quickly excreted in the urine, large and prolonged doses can result in the formation of bladder and kidney stones, interfere...

Known also as vitamin B complex, these are fragile, water-soluble substances, several of which are particularly important to carbohydrate metabolism. Vitamin B1 Thiamine , or vitamin B1, a colorless, crystalline substance, acts as a catalyst in carbohydrate metabolism, enabling pyruvic acid to be absorbed and carbohydrates to release their energy. Thiamine also plays a role in the synthesis of nerve-regulating substances. Deficiency in thiamine causes beriberi, which is characterized by muscular weakness, swelling of the heart, and leg cramps and may, in severe cases, lead to heart failure and death. Foods richest in thiamine are pork, organ meats (liver, heart, and kidney), brewer's yeast, lean meats, eggs, leafy green vegetables, whole or enriched cereals, wheat germ, berries, nuts, and legumes. Milling of cereal removes those portions of the grain richest in thiamine; consequently, white flour and polished white rice may be lacking in the vitamin. Widespread enrichment of flour ...

Vitamin A is a pale yellow primary alcohol derived from carotene. It affects the formation and maintenance of skin, mucous membranes, bones, and teeth; vision; and reproduction. An early deficiency symptom is night blindness (difficulty in adapting to darkness); other symptoms are excessive skin dryness; lack of mucous membrane secretion, causing susceptibility to bacterial invasion; and dryness of the eyes due to a malfunctioning of the tear glands, The body obtains vitamin A in two ways. One is by manufacturing it from carotene, a vitamin precursor found in such vegetables as carrots, broccoli, squash, spinach, kale, and sweet potatoes. The other is by absorbing ready-made vitamin A from plant-eating organisms. In animal form, vitamin A is found in milk, butter, cheese, egg yolk, liver, and fish-liver oil. Excess vitamin A can interfere with growth, stop menstruation, damage red blood corpuscles, and cause skin rashes, headaches, nausea, and jaundice.

Undulant Fever, also known as brucellosis, infectious disease caused by various species of bacteria of the genus Brucella, transmitted to humans from lower animals, especially cattle, hogs, and goats. Human beings acquire the disease through contact with infected animals or by drinking their raw milk. The disease has been known as Malta fever, Bang's disease, Mediterranean fever, rock fever, and goat fever. In animals the disease generally can cause partial sterility, decreased milk supply, and abortion of a fetus. In humans undulant fever assumes acute and chronic forms. The acute form is characterized by weakness, chills, and high night fevers and often results in central nervous system disorders, painful joints, and miscarriage. Chronic undulant fever is difficult to diagnose, as the symptoms are exceedingly varied and vague. A diagnostic blood agglutination test is available. As a rule human beings suffering from undulant fever respond favorably to the administration of broad-...

Ulcerative Colitis, a chronic disease of unknown cause in which the lining of the colon and rectum becomes severely inflamed and eventually wears away, forming shallow sores known as ulcers. Frequently the colon is permanently damaged. Ulcerative colitis, together with a related condition called Crohn’s disease, are generally referred to as inflammatory bowel diseases (IBDs). Most people with ulcerative colitis have inflammation in their descending colon, the section of the large intestine stretching from the left side of the abdomen to the pelvis, and in the sigmoid colon, the section of the intestine that is joined to the rectum. Some people have inflammation and ulceration in all of the large intestine. The disease does not affect the small intestine. Most people have only mild or moderate forms of the disease, with symptoms that include rectal bleeding, diarrhea, and feces that contains mucus, all of which are easily controlled with medication. People with a more severe form of the...

Tumor, broadly interpreted, any abnormal local increase in size of a tissue or organ. Medical research at the microscopic level, however, has made clear that swelling can be due either to the infiltration of cells from another part of the body or to the proliferation of cells originating within the affected site itself; only the latter circumstance is called a tumor. Tumors are classified as either benign or malignant, although the benign-malignant distinction is not universally useful. The most important property rendering a tumor malignant is the ability to invade nearby or distant tissues; this spread to distant tissues is called metastasis, and it usually occurs by means of the blood or lymph vessels. Some so-called benign tumors can kill without metastasizing. Chief among these are brain tumors called gliomas, which can grow large enough to exert substantial pressure on nearby brain structures and destroy respiratory function. A liver tumor can kill by destroying the vital functio...

Trypanosomiasis, also sleeping sickness, endemic, and sometimes epidemic, chronic disease caused by a protozoan blood parasite, genus Trypanosoma. In cattle and other animals, which serve as the reservoir for the protozoa, the disease is called nagana. Two variations of the disease occur in central and western Africa, both of them transmitted in the salivary glands of infected tsetse flies. The most common is caused by T. brucei gambiense, whereas a more local version is caused by T. brucei rhodesiense. African sleeping sickness begins with a chancre at the site of the insect bite, an accelerated heartbeat, an enlargement of the spleen, and rash and fever. Over the next few months the nervous system is attacked, with accompanying mood changes, sleepiness, lack of appetite, eventual coma, and, frequently, death. Chagas' disease, which more frequently attacks children, also involves fever and damage to the spleen and nervous system, as well as to the liver and the heart muscles. It i...

Trench Mouth, acute infectious disorder of the mucous membranes of the mouth and throat, so called from its prevalence among World War I soldiers. It is characterized by painful ulcerations. Predisposing factors for infection include poor oral hygiene. The main causative organisms are the bacillus Fusiformis dentium and the spirillum Borrelia vincenti. Painful and bleeding gums are the chief symptoms, and they are usually accompanied by malodorous breath and an unpleasant taste in the mouth. Treatment consists of relieving the painful symptoms of the acute bacterial state and correcting local and systemic predisposing causes of the disease. Antibiotics are usually effective in controlling the infection.

Toxic Shock Syndrome (TSS), rare disease associated with strains of the bacterium Staphylococcus aureus, a common inhabitant of the skin, oral cavity, and vagina. Under certain conditions the bacterium produces a toxin that apparently attacks the immune system through the bloodstream, in turn permitting more toxin to be produced. Liver function is also altered, resulting in liver and kidney damage. Symptoms of TSS include rash, high fever, lowered blood pressure, diarrhea, and vomiting. TSS has caused death in about 3 percent of reported cases. The disease can be treated with antibiotics.

Toxemia, poisoned condition of the blood caused by the presence of toxic materials, usually bacterial but occasionally chemical or hormonal in nature. When bacteria themselves find entrance into the bloodstream, the condition is known as bacteremia. Toxins are not due to absorption of putrefied or fermented foodstuffs, nor are they absorbed from the colon in conditions of constipation. The term toxemia is also sometimes applied to preeclampsia, a condition that occasionally occurs in late pregnancy and is characterized by high blood pressure and kidney malfunction.

Thrush (medicine), fungal infection characterized by creamy-white, curdlike patches on the tongue and other mucosal surfaces of the mouth. The disease is caused by an overgrowth of Candida albicans, a species of yeast that normally inhabits the mucous membranes as a benign saprophyte. Those most susceptible to thrush include adults whose immune systems have been weakened by antibiotics, steroids, or, most commonly, acquired immunodeficiency syndrome (AIDS). Infants can become infected during birth if the mother has a vaginal yeast infection. When the curdlike discharge is removed from patches of thrush, raw and bleeding areas are visible and can be especially painful. If left untreated, these superficial lesions may allow the yeast to spread to other areas of the body. In cases of severe immunosuppression or prolonged antibiotic therapy, the organism can invade the major organs, causing serious complications. Diagnosis requires microscopic identification of the pseudomycelial (branchin...

Thiamine, also called vitamin B1, a substance that enables carbohydrates in the body to release the energy required for cellular function, known as metabolism. Thiamine also plays a vital role in the activities of enzymes, proteins that are involved in bodily processes such as digestion. Good sources of thiamine include wheat germ, dry beans, peas, enriched cereals and breads, pasta, nuts, eggs, and most vegetables. Lean pork is one of the best sources of the vitamin, as are organ meats, such as liver. Thiamine deficiency is a risk for the elderly, for people of all ages who participate in strenuous exercise, and for those who are severely ill. A severe lack of thiamine causes the vitamin-deficiency disease known as beriberi, a neurological and cardiovascular disorder characterized by muscular weakness, swelling of the heart, leg cramps, and, in severe cases, heart failure and death. Thiamine deficiency in severe alcoholics (a result of malnutrition) may lead to a central nervous syste...

Tetanus, serious infectious disease of the nervous system, in which a bacterial toxin causes severe muscle spasm. Also called lockjaw, the bacterial infection occurs when wounds are contaminated with a bacillus, Clostridium tetani, which is found everywhere but which is especially likely to be present in street dirt. It is an anaerobic bacillus—that is, one that lives without oxygen, and thus when introduced into human tissue, usually at the time of an injury, it can multiply where the oxygen is deficient. This occurs both in deep, penetrating wounds and in crushing wounds with extensive tissue destruction. As the bacillus multiplies, large amounts of exotoxin are released into the surrounding tissues. The incubation period varies from two weeks to several months, but generally is about two weeks. The first symptoms are usually headache and depression, followed by difficulty in swallowing and in opening the jaws. Stiffness of the neck develops and gradually a spasm of the cheek muscles...

Syphilis, infectious disease caused by the spirochete Treponema pallidum and usually transmitted by sexual contact or kissing. Infection from contaminated objects is infrequent, because drying quickly kills the organisms. A fetus carried by a woman with syphilis may contract the disease, a condition called congenital syphilis. Syphilis is detected by symptoms and verified by one of several tests performed on the blood or spinal fluid, the most common of which is the VDRL (venereal disease research laboratory) test. The preferred drug for treatment is benzathine penicillin, which is given in two injections one week apart for all stages but neurosyphilis. For this advanced stage, the antibiotic is given three times at weekly intervals. Syphilis control includes tracking down all sexual contacts of infected persons and treating those who had contact during the infectious period. Use of condoms offers some protection against contracting syphilis.

Streptococcus, genus of spherical, gram-positive, aerobic bacteria. The streptococci occur in pairs or chains, and some species are pathogenic in humans. Streptococcal infections include strep throat, scarlet fever, erysipelas, puerperal fever, and some pneumonias. The drugs of choice for treating such infections are penicillin and erythromycin. Cultures of nonpathogenic lactic streptococci are used in the fermentation of dairy products such as cheese and buttermilk.

Smallpox, highly contagious viral disease that is often fatal. The disease is chiefly characterized by a skin rash that develops on the face, chest, back, and limbs. Over the course of a week the rash develops into pustular (pus-filled) pimples resembling boils. In extreme cases the pustular pimples run together—usually an indication of a fatal infection. Death may result from a secondary bacterial infection of the pustules, from cell damage caused by the viral infection, or from heart attack or shock. In the latter stages of nonfatal cases, smallpox pustules become crusted, often leaving the survivor with permanent, pitted scars. Smallpox is caused by a virus. An infected person spreads virus particles into the air in the form of tiny droplets emitted from the mouth by speaking, coughing, or simply breathing. The virus can then infect anyone who inhales the droplets. By this means, smallpox can spread extremely rapidly from person to person.

Sickle-Cell Anemia, genetic disorder of the blood leading to frequent and severe infections, damage to major organs, and episodes of unpredictable pain in the back, chest, abdomen, and extremities. Early symptoms appear at about six months of age and may include serious infections, pain and swelling in the hands and feet, and enlargement of the abdomen and heart. Sickle-cell anemia is caused by a defective gene that produces an abnormal form of hemoglobin, the component of red blood cells responsible for transporting oxygen from the lungs to the tissues. The abnormal hemoglobin, called hemoglobin S, distorts red blood cells after they release oxygen in the tissues. These distorted cells are called sickled cells because of their resemblance to the sickle, a type of crescent-shaped cutting blade used in agriculture. The sickled shape makes it difficult for these cells to pass through tiny blood vessels, resulting in intensely painful blockages that prevent vital oxygen and nutrients in t...

Scurvy, disease of human beings caused by a prolonged deficiency of vitamin C, or ascorbic acid, in the diet. It is characterized by progressive bodily weakness, spongy and inflamed gums, loose teeth, swollen and tender joints, and a tendency toward ecchymosis, or absorption by the tissues of blood from ruptured blood vessels. Anemia often occurs as a direct result of such hemorrhage. Lack of vitamin C in the diet prevents the formation of connective tissues that hold the body's structures together, such as tendons, ligaments, bone, dentin, and cartilage. The disease may appear in adults after about six months of complete lack of vitamin C.

Schistosomiasis or Bilharziasis, widespread disease caused by the infestation of the human body by (flukes) commonly called blood flukes, of the genus Schistosoma. Blood flukes spend most of their life cycle in two hosts; the adult stage is spent in a mammal, usually humans, and the immature stages are spent in certain snails. Eggs discharged from the host hatch into larval forms in fresh water; from the water, the larvae, miracidia, invade the snail that acts as an intermediate host. The larval form of the parasite undergoes partial maturation in the snail, then escapes back into the water, as mature larvae called cercariae. At this stage they penetrate the skin of the host from the water and then migrate through the blood vessels to specific capillaries as maturation completes. There they remain and lay eggs.

Rickets, nutritional disorder characterized by skeletal deformities. Rickets is caused by a decreased concentration of the mineral hydroxyapatite in bones and cartilage due to low levels of calcium and phosphorus in the blood. Vitamin D is essential for the maintenance of normal calcium and phosphorus levels. Classic rickets, a deficiency disease of children characterized by improper development or hardening of bones, is due to lack of sufficient vitamin D in the diet, or to insufficient ultraviolet radiation from direct sunlight, a lack that prevents conversion of the element 7-dehydrocholesterol in the skin to vitamin D. The type of skeletal deformities depends largely on the child's age when the vitamin-D deficiency occurs. A child who has not yet learned to walk develops vertebral curvatures; a walking child develops leg curvatures.

Riboflavin, also called vitamin B2 or vitamin G, a substance essential for the breakdown and utilization of carbohydrates, fats, and proteins in the body, and in the production of energy. Riboflavin plays a vital role in the health of the skin and is needed for production of certain hormones by the adrenal glands, the pair of hormone-secreting organs that sit on top of each kidney. Because it is a water-soluble vitamin—that is, it is not stored in the body, but is excreted in sweat or urine—riboflavin needs to be constantly replaced in the body. Rich sources of riboflavin include milk, cheese and yogurt, lean meat, liver, green leafy vegetables, eggs, and enriched breads and cereals. Because cheese and milk are such good dietary sources of the vitamin, lactose-intolerant people, including many of the elderly, are vulnerable to deficiency problems. Individuals who exercise often, especially women, are also at risk for riboflavin deficiency. A lack of riboflavin in the diet may result in...

Tracheotomy, surgical operation in which an incision, or opening, is cut through the front of the neck and into the trachea , or windpipe. The oldest mention of the operation in medical literature is found in the writings of the Greek physician Galen (2nd century ad). A tracheotomy creates an alternate passage to the lungs for air that cannot flow from the nose and mouth through the trachea because of an obstruction. Obstructions may occur when a foreign body lodges in the larynx , or voice box, above the trachea; as a result of swelling or spasm of the larynx or vocal cords; or from infection and swelling of the epiglottis , the thin flap of cartilage covering that keeps food and liquid out of the trachea. The purpose of a tracheostomy is to keep the airway from closing prematurely and to enable the physician to take further measures, if necessary, to ensure that the patient has a patent airway. When a tracheotomy is performed on a patient suffering from severe bronchial or lung co...

Syringe, device used to eject or collect fluids. A syringe consists of a hollow barrel made of glass, plastic, or metal with a close-fitting plunger or a rubber bulb on one end. The other end of the barrel has a nozzle which may be designed to accept a needle or other attachment. The barrel fills by suction when the plunger is pulled out, or when the bulb is compressed and subsequently allowed to inflate. Pushing in the plunger or squeezing the bulb forces the fluid out through the needle or nozzle. Syringes come in many sizes and serve many purposes. The small syringe used in medicine to give hypodermic injections (forceful introduction of medication or fluid beneath the skin) has a plunger and a fine hollow needle. Its barrel is calibrated, featuring a set of equally spaced marks that measure the volume of its contents. The larger medical syringes used to cleanse wounds or body cavities, or to extract unwanted fluids from the body, have wider, flexible nozzles on one end and rubber b...