Glossary - A

Acne vulgaris

Acne vulgaris is an androgenically stimulated, inflammatory disorder of the sebaceous glands, resulting in comedones, papules, inflammatory pustules and occasionally, scarring. The disease affects the skin/exocrine system. Virtually 100% of adolescents in the USA are affected to some degree. 15% will seek medical advice. The predominant ages affected are those in between early to late puberty, although some cases will persist into the third and fourth decade. Males and females are equally susceptible to the disease. Signs and symptoms include, closed comedones, open comedones, nodules or papules, pustules and scars. The lesions occur over the forehead, cheeks and nose, and may extend over the central chest and back. Androgens stimulate the rate of keratin turnover in the sebaceous gland. The keratin plug, visible as a comedone, causes an accumulation of sebum in the gland. The presence of Propionibacterium acnes stimulate inflammatory response to the sebum, which results in papule and pustule formation. Risk factors include, adolescence, male sex, androgenic steroids, oily cosmetics, rubbing or occluding the skin surface, drugs (iodides or bromides, lithium, phenytoin), systemic corticosteroid, virilization disorders, and hot, humid climates

Acromegaly

Acromegaly is a disorder due to excessive secretion of pituitary growth hormone, characterized by progressive enlargement of the head and face, hands and feet, and thorax. Its usual course is progressive. The cause of the disease is a growth hormone excess from a pituitary adenoma.

Adenocarcinoma of the gallbladder

Adenocarcinoma of the gallbladder is the most frequent cause of extrabiliary obstruction. Characteristics include nausea, vomiting, abdominal pain, anorexia, jaundice, hepatomegaly and enlarged gallbladder Causes include cholelithias and/or calcified gallbladder.

Adenocarcinoma of the rectum

Adenocarcinoma of the rectum is a slow- growth rate malignancy that depends on routine examination to discover before it reaches symptom producing size. The most common symptom is blood passage at the time of bowel movement. Causes include ulcerative colitis, previous rectal cancer and/or familial polyposis.

Alcoholism

Alcoholism is an illness which is characterized by significant physiologic, and/or social dysfunctions associated with persistent and excessive use of alcohol. The disease affects the nervous and gastrointestinal systems. Studies of twins and adoption support a genetic influence. Ten percent of men and three and a half percent of women in the United States have the disease. It is most common in adults between the ages of 18 and 29. Psychological and social dysfunction, marital problems, anxiety, depression, insomnia, social isolation, child or spouse abuse, alcohol-related arrests, legal problems, preoccupation with recreational drinking, repeated attempts to stop or reduce drinking, loss of interest in non-drinking activities, employment problems, blackouts and complaints by family members or friends about alcohol-related behavior, are the known symptoms of the disease. The causes of the alcoholism are multifactorial, including biological, psychological and sociocultural factors. The biological factors include deficiencies in the brain neuro- transmitters and/or cell membrane receptors and enzyme system malfunctions. There is no evidence for a characteristic disposition for the disease. Risk factors include: alcohol use, use of other psychoactive drugs, a family history of alcohol abuse, young age, single, male, peer group pressure, heavy drinking and increased accessibility of alcohol.

Allele

Allele- different forms of the same gene at a given location.

Alzheimer disease

Alzheimer disease is a degenerative organic mental disease, characterized by progressive brain deterioration and dementia; frequently occurring after the age of 65. The diagnosis is made on clinical grounds after ruling out treatable disorders with similar characteristics. Long-term care costs to the nation is approximately 40 billion dollars annually.The disease affects the nervous system. Two of every 350 individuals in the United States have the disease. The predominant age range is between ages 40 and 75. Females are more likely than males to have the disease. Symptoms of the disease include: abnormal space perception, amnesia, anhedonia, anxiety, confabulation, dementia, depression, intellectual decline, loss of interest, recent memory loss, restlessness and/or progressive cognitive impairment. Causes are unknown, but aging is the greatest risk factor for the disease.

Amniocentesis

Amniocentesis- a diagnostic procedure performed during the second trimester of pregnancy, where amniotic fluid is withdrawn from the amniotic sac surrounding the fetus.

Amplification

Amplification-the production of multiple copies of a DNA sequence.

Anorexia Nervosa

Anorexia nervosa is a disease that produces body dissatisfaction, significant weight loss, and amenorrhea (in females), not accounted for any physical illness. Approximately 1% of females and between 5 and 10% of males in the United States is afflicted with the disease which affects the nervous, metabolic, gastrointestinal, cardiovascular and reproductive systems. It is more predominant in adolescents and young adults. The signs and symptoms, are usually insidious in onset, and the onset, which in turn, is usually stress related. Pronounced weight loss, denial, feelings of gluttony even when emaciated, preoccupation with weight, reduction in food intake, elaborate food rituals, extensive exercise, depression, dry skin, fine, lanugo hair on extremities, hypotension and bradycardia, hypothermia and peripheral edema are other known symptoms. The causes of the disease are unknown, although emotion plays a large role. There is an obsessive compulsive disorder in 10-13% of the patients, and in 50-75% there is major depression and/or dysthymia. Those at risk include someone with a perfectionist personality, low self esteem, high achievement standards, ambivalence regarding dependence and independence, someone has a lot of stress, and an unstable body image.

Arteriosclerotic heart disease (AHD)

Arteriosclerotic heart disease is the thickening of the arterial wall, along with the loss of elasticity, that progressively blocks the coronary arteries and their main branches. The process is chronic, occurring over many years, and is the most common cause of cardiovascular disability and death in the United States. Elevated total serum cholesterol and low density lipoproteins are involved in the development of arteriosclerosis, as is the process of aging and anatomic changes. The disease affects the cardiovascular system, and is hereditary. AHD is responsible for 35% of the deaths of males between the ages of 35 and 50. The predominant ages which are affected by this disease range between 50-60 for males and between 60-70 for females. The signs and symptoms of the disease may remain critically silent, and, in some instances of ischemia, may be clinical manifestations which include substernal chest pain, exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, extrasystoles, irregular rhythm, tachycardia, systolic murmur, cardiomegaly and pedal edema. Causes of AHD include atherosclerosis, narrowing of coronary arteries, embolism comprising coronary arteries at orifices and subintimal atheromas in large and medium vessels. Risk factors include elevated low density lipoproteins (LDL), decreased high density lipoproteins (HDL), elevated triglycerides, smoking, family history of premature arteriosclerosis, obesity, hypertension, stress, sedentary life style, increasing age, male sex, female postmenopausal status and diabetes mellitus.

Aplastic anemia

Aplastic anemia is a form of anemia in which the bone marrow fails to produce adequate numbers of peripheral blood elements. The usual course is insidious. Pure red cell aplasia is a related syndrome that is caused by a selective failure of the production of erythroid elements. It can be associated with thymomas. Constitutional (Fanconi's) anemia is associated with congenital anomalies. In a constitutional, the autosomal recessive gene is the culprit. In the acquired form the genetic pattern is undetermined. It affects the Hemic/Lymphatic/Immunologic system and is not very prevalent in the United States. Males and females have an equal chance of contracting the disorder. Constitutional affects children and young adults, while the acquired form affects all ages. Signs and symptoms of the disease include: dyspnea, fatigue, fever, pallor, palpitations, progressive weakness, retinal flame hemorrhages, systolic ejection murmur and/or weight loss. In the constitutional form, additional symptoms include short stature, microcephaly radius and thumb anomalies, renal anomalies and hypospadias. Causes of the disease can be idiopathic, injury to pleuripotential stem cells, destruction of pleuripotential stem cells, toxic exposure, infectious hepatitis, radiation treatment, drugs, pregnancy, inherited, and/or immunologic injury. The risk factors include: viral illness, toxin exposure, and/or tumors of thymus.

Assortive Mating

Assortive Mating-nonrandom mating in which a member of a particular subpopulation is more likely to mate with other members of that subpopulation.

Asthma

Asthma is a disorder of the tracheobronchial tree, characterized by mild to severe obstruction to airflow. Symptoms vary from coughing to dyspnea, and are generally episodic or paroxysmal, but may be persistent. The clinical hallmark is wheezing, but cough may be the predominant symptom. It is commonly misdiagnosed as "recurrent pneumonia" or "chronic bronchitis." The acute symptoms are characterized by a narrowing of the large and small airways because of the spasm of bronchial mucosa and the production of mucus. There is a familial association of reactive airway disease, ectopic dermatitis, and allergic rhinitis. 10 million new cases of asthma are diagnosed annually. It is a leading cause of missed school days (7.5 million annually), and is prevalent between 7-19% of the children in the United States.

Though the disease may affect any age, one half of the cases are among children below the age of 10, with more males than females contracting the disease. The main symptoms of asthma include wheezing, coughing, prolonged expiration, hyperresonance, decreased breath sounds, nocturnal attacks, pulsus paradoxes, cyanosis, tachycardia, accessory respiratory muscle use, flattened diaphragms and nasal polyp. Growth is usually normal and clubbing is not seen in the disease.

Atelectasis

Atelectasis is the portion of the lung which is nonaerated, but otherwise normal. It may be an asymptomatic finding on chest roentgenogram or associated with symptoms. Pulmonary blood flow to the area of the atelectasis is usually reduced, thereby limiting shunting and hypoxia. Diagnosis and therapy are directed at the basic cause. The disease affects both pulmonary as well as the cardiovascular systems. The genetics of the disease depend on general anesthesia and in intensive care, with high inspired oxygen concentrations. It affects all ages, including male and female equally. Signs and symptoms of a small atelectasis is commonly asymptomatic and produces no change in the overall clinical presentation. In a large atelectasis, symptoms include tachypnea, coughing, hypoxia, dullness to percussion, absent breath sounds as if airway is occluded, bronchial breathing if airway is patent, diminished chest expansion, tracheal displacement, and wheezing.

The causes include an increased alveolar surface tension because of cariogenic or non-cardiogenic pulmonary edema, primary surfactant deficiency, or infection. Resorptive atelectasis due to airway obstruction from lumenal obstruction, compression of the lung, increased pleural space, chest wall restriction because of skeletal deformity and/or muscular weakness, are other causes of the disease. Those who are at risk include smokers, the obese as well as individuals with short, wide thoraces.

Atherosclerosis

Atherosclerosis occurs when the deposits of yellowish plaques(atheromas) containing cholesterol, lipid material, and lipophages form within the intima and the inner media of large and medium sized arteries. It affects the cardiovascular system and is genetically link. The prevalence in the United States is large, but it is declining steadily. The effects upon the brain, kidneys, extremities and other vital organs, form the leading cause of morbidity and mortality in the United States and as well as most Western countries. Complications of atherosclerosis account for one-half of all deaths and one-third of deaths in individuals between the ages 35 and 65. The predominant age for this disease is 35 and older, and it is more common in males. The signs and symptoms include: stenosis, thrombosis, aneurism, and embolus, while the causes include biochemical, physiologic, environmental factors that lead to the thickening and occlusion of the lumen of arteries and aging. The risk factors for the disease include hypertension, tobacco smoking, diabetes, obesity, increasing age, type A behavior, male gender, hard drinking water, family history of the disease, decreased HDL and decreased LDLs.

Autoimmune Disorder

Autoimmune Disorder-a disorder in which antibodies are directed against the individuals own antigens.

Autoimmune Hemolytic anemia

Autoimmune Hemolytic anemia, is an acquired anemia induced by the binding of auto antibodies and/or a complement to the red cells. There are three main types: warm antibody, cold reacting antibody and drug induced. It affects the Hemic/Lymphatic/Immunologic systems. The genetic factors are unknown. The incidence is less than 50 years of age. Females are more predisposed to the disease. The signs and symptoms include weakness, fatigue, exertional dyspnea, dizziness, palpitations, malaise dyspnea, pallor jaundice splenomegaly, hepatomegaly, tachycardia, and/or anemia. The causes in a warm antibody can be: idiopathic, neoplasia, collagen vascular disease, and/or viral infection. In a cold antibody the cause can be idiopathic, infection, neoplasia, cold agglutinin disease.

Autosome

Autosome-any chromosome other than the sex chromosomes.

Autosomal Disease

Autosomal Disease-a disease encoded by a gene on one of the 22 pairs of autosomes.

 

 

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