Friday, June 19, 2009
Acanthamoeba keratitis
Acanthamoeba keratitis: Infection of the cornea by acanthamoeba, a microscopic water-borne ameba. The disease tends to occur in people who wear contact lens. It can accompany a bacterial infection of the eye. Acanthamoeba keratitis can produce corneal ulceration and result in severe loss of vision and even blindness. Signs and symptoms are persistent redness and pain in the eye. Treatment is with multiple antibiotics, often including antifungal drugs, and sometimes surgery after the infection has subsided.
Abused inhalant
Abused inhalant: A breathable chemical vapor that is abused. All abused inhalants produce psychoactive (mind-altering) effects. Abused inhalants fall into the following categories:
Solvents
Industrial or household solvents or solvent-containing products, including paint thinners or removers, degreasers, dry-cleaning fluids, gasoline, and glue
Art or office supply solvents, including correction fluids, felt-tip-marker fluid, and electronic contact cleaners
Gases
Gases used in household or commercial products, including butane lighters and propane tanks, whipping cream aerosols or dispensers (whippets), and refrigerant gases
Household aerosol propellants and associated solvents in items such as spray paints, hair or deodorant sprays, and fabric protector sprays
Medical anesthetic gases, such as ether, chloroform, halothane, and nitrous oxide ("laughing gas")
Nitrites
Aliphatic nitrites, including cyclohexyl nitrite, an ingredient found in room odorizers; amyl nitrite, which is used for medical purposes; and butyl nitrite (previously used to manufacture perfumes and antifreeze), which is now an illegal substance.
Nearly all abused inhalants produce short-term effects similar to anesthetics, which act to slow down the body's functions. When inhaled via the nose or mouth into the lungs in sufficient concentrations, inhalants can cause intoxicating effects. Intoxication usually lasts only a few minutes. However, sometimes users extend this effect for several hours by breathing in inhalants repeatedly. Initially, users may feel slightly stimulated. Successive inhalations make them feel less inhibited and less in control. If use continues, users can lose consciousness.
Sniffing highly concentrated amounts of the chemicals in solvents or aerosol sprays can directly induce heart failure and death within minutes. This syndrome, known as "sudden sniffing death," can result from a single session of inhalant use by an otherwise healthy young person. Sudden sniffing death is particularly associated with the abuse of butane, propane, and chemicals in aerosols.
High concentrations of inhalants also can cause death from suffocation by displacing oxygen in the lungs and then in the central nervous system so that breathing ceases. Deliberately inhaling from an attached paper or plastic bag or in a closed area greatly increases the chances of suffocation. Even when using aerosols or volatile products for their legitimate purposes (such as painting, cleaning), it is wise to do so in a well-ventilated room or outdoors.
Chronic abuse of solvents can cause severe, long-term damage to the brain, the liver, and the kidneys. Other harmful irreversible effects may be caused by abuse of specific solvents.
Solvents
Industrial or household solvents or solvent-containing products, including paint thinners or removers, degreasers, dry-cleaning fluids, gasoline, and glue
Art or office supply solvents, including correction fluids, felt-tip-marker fluid, and electronic contact cleaners
Gases
Gases used in household or commercial products, including butane lighters and propane tanks, whipping cream aerosols or dispensers (whippets), and refrigerant gases
Household aerosol propellants and associated solvents in items such as spray paints, hair or deodorant sprays, and fabric protector sprays
Medical anesthetic gases, such as ether, chloroform, halothane, and nitrous oxide ("laughing gas")
Nitrites
Aliphatic nitrites, including cyclohexyl nitrite, an ingredient found in room odorizers; amyl nitrite, which is used for medical purposes; and butyl nitrite (previously used to manufacture perfumes and antifreeze), which is now an illegal substance.
Nearly all abused inhalants produce short-term effects similar to anesthetics, which act to slow down the body's functions. When inhaled via the nose or mouth into the lungs in sufficient concentrations, inhalants can cause intoxicating effects. Intoxication usually lasts only a few minutes. However, sometimes users extend this effect for several hours by breathing in inhalants repeatedly. Initially, users may feel slightly stimulated. Successive inhalations make them feel less inhibited and less in control. If use continues, users can lose consciousness.
Sniffing highly concentrated amounts of the chemicals in solvents or aerosol sprays can directly induce heart failure and death within minutes. This syndrome, known as "sudden sniffing death," can result from a single session of inhalant use by an otherwise healthy young person. Sudden sniffing death is particularly associated with the abuse of butane, propane, and chemicals in aerosols.
High concentrations of inhalants also can cause death from suffocation by displacing oxygen in the lungs and then in the central nervous system so that breathing ceases. Deliberately inhaling from an attached paper or plastic bag or in a closed area greatly increases the chances of suffocation. Even when using aerosols or volatile products for their legitimate purposes (such as painting, cleaning), it is wise to do so in a well-ventilated room or outdoors.
Chronic abuse of solvents can cause severe, long-term damage to the brain, the liver, and the kidneys. Other harmful irreversible effects may be caused by abuse of specific solvents.
Thursday, June 18, 2009
Abductor muscle
Abductor muscle: Any muscle used to pull a body part away from the midline of the body. For example, the abductor muscles of the legs spread the legs away from the midline and away from one another.
The word "abductor" comes from the Latin prefix "ab-" meaning "away from" + "ducere" meaning "to draw or lead" = "to draw away from."
The prefix "ab-" is opposed to the prefix "ad-". Therefore, the opposite of "abductor" is "adductor." An abductor muscle opposes an adductor muscle.
The word "abductor" comes from the Latin prefix "ab-" meaning "away from" + "ducere" meaning "to draw or lead" = "to draw away from."
The prefix "ab-" is opposed to the prefix "ad-". Therefore, the opposite of "abductor" is "adductor." An abductor muscle opposes an adductor muscle.
Abduction
Abduction: In medicine, the movement of a limb away from the midline of the body. Abduction of both legs spreads the legs. The opposite of abduction is adduction. Adduction of the legs brings them together.
From the Latin "ab-" meaning "away from" + "ducere" meaning "to draw or lead" = "to draw away from."
From the Latin "ab-" meaning "away from" + "ducere" meaning "to draw or lead" = "to draw away from."
Abducent nerve
Abducent nerve: A small motor nerve that has one task: to supply a muscle called the lateral rectus muscle that moves the eye outward.
Paralysis of the abducent nerve causes inward turning of the eye (internal strabismus) leading to double vision.
The abducent nerve is the sixth cranial nerve. All 12 cranial nerves, the abducent nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column.
The word "abducent" comes from the Latin "ab-", away from + "ducere", to draw = to draw away. The abducent (or abducens) operates the lateral rectus muscle that draws the eye toward the side of the head. The abducent nerve is also called the abducens nerve.
Paralysis of the abducent nerve causes inward turning of the eye (internal strabismus) leading to double vision.
The abducent nerve is the sixth cranial nerve. All 12 cranial nerves, the abducent nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column.
The word "abducent" comes from the Latin "ab-", away from + "ducere", to draw = to draw away. The abducent (or abducens) operates the lateral rectus muscle that draws the eye toward the side of the head. The abducent nerve is also called the abducens nerve.
Abdominal pain
Definition of Abdominal pain
Abdominal pain: Pain in the belly (the abdomen). Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone (pubic ramus) below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (the skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (from beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.
Occasionally, pain may be felt in the abdomen even though it is arising from organs that are close to but not within the abdominal cavity, for example, the lower lungs, the kidneys, and the uterus or ovaries. This latter type of pain is called "referred" pain because the pain, though originating outside the abdomen, is being referred to (felt) in the abdominal area.
Abdominal pain can be acute and sudden in onset, or the pain can be chronic and longstanding. Abdominal pain may be minor and of no great significance, or it can reflect a major problem involving one of the organs in the abdomen. The characteristics of the pain--location, timing, duration, etc. are important in diagnosing its cause. Persistent or severe abdominal pain should be evaluated by a physician.
Acute abdominal pain may require urgent surgery such as for a twisted ovarian cyst, ectopic pregnancy, intestinal obstruction, appendicitis, peritonitis, perforated peptic ulcer, perforated diverticulitis, or abdominal aortic aneurysm. Patients with gallbladder disease, pancreatitis, or a kidney stone may also need urgent treatment. Acute or chronic abdominal pain may also call for medical (nonsurgical) therapy.
The causes of abdominal pain depend on sex and age of the patient. A woman may have a twisted ovarian cyst while a man may have testicular torsion with a twisted testis. Abdominal pain in infants and small children may be due to intestinal obstruction from atresia or stenosis of the intestine, esophageal webs, intussusception, volvulus, imperforate anus, and Hirschsprung disease. These causes of abdominal pain are rarely, if ever, encountered in adults
Abdominal pain: Pain in the belly (the abdomen). Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone (pubic ramus) below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (the skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (from beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.
Occasionally, pain may be felt in the abdomen even though it is arising from organs that are close to but not within the abdominal cavity, for example, the lower lungs, the kidneys, and the uterus or ovaries. This latter type of pain is called "referred" pain because the pain, though originating outside the abdomen, is being referred to (felt) in the abdominal area.
Abdominal pain can be acute and sudden in onset, or the pain can be chronic and longstanding. Abdominal pain may be minor and of no great significance, or it can reflect a major problem involving one of the organs in the abdomen. The characteristics of the pain--location, timing, duration, etc. are important in diagnosing its cause. Persistent or severe abdominal pain should be evaluated by a physician.
Acute abdominal pain may require urgent surgery such as for a twisted ovarian cyst, ectopic pregnancy, intestinal obstruction, appendicitis, peritonitis, perforated peptic ulcer, perforated diverticulitis, or abdominal aortic aneurysm. Patients with gallbladder disease, pancreatitis, or a kidney stone may also need urgent treatment. Acute or chronic abdominal pain may also call for medical (nonsurgical) therapy.
The causes of abdominal pain depend on sex and age of the patient. A woman may have a twisted ovarian cyst while a man may have testicular torsion with a twisted testis. Abdominal pain in infants and small children may be due to intestinal obstruction from atresia or stenosis of the intestine, esophageal webs, intussusception, volvulus, imperforate anus, and Hirschsprung disease. These causes of abdominal pain are rarely, if ever, encountered in adults
Abdominal muscles
Abdominal muscles: A large group of muscles in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as the intestines in place. Abdominal muscles play a key role in exercises such as "sit-ups." They are informally called the "abs".
Abdominal hysterectomy
Abdominal hysterectomy: Surgical removal of the uterus (a hysterectomy) done through an incision made in the abdominal wall. As opposed to a vaginal hysterectomy in which the incision is made within the vagina.
Abdominal guarding
Abdominal guarding: Tensing of the abdominal wall muscles to guard inflamed organs within the abdomen from the pain of pressure upon them. The tensing is detected when the abdomen wall is pressed.
Guarding is a characteristic finding in the physical examination for an abruptly painful abdomen (an acute abdomen) with inflammation of the inner abdominal (peritoneal) surface due, for example, to appendicitis or diverticulitis. The tensed muscles of the abdominal wall automatically go into spasm to keep the tender underlying tissues from being touched.
Guarding is a characteristic finding in the physical examination for an abruptly painful abdomen (an acute abdomen) with inflammation of the inner abdominal (peritoneal) surface due, for example, to appendicitis or diverticulitis. The tensed muscles of the abdominal wall automatically go into spasm to keep the tender underlying tissues from being touched.
Abdominal cavity
Abdominal cavity: The cavity within the abdomen, the space between the abdominal wall and the spine.
The abdominal cavity is hardly an empty space. It contains a number of crucial organs including the lower part of the esophagus, the stomach, small intestine, colon, rectum, liver, gallbladder, pancreas, spleen, kidneys, and bladder.
The abdominal cavity is hardly an empty space. It contains a number of crucial organs including the lower part of the esophagus, the stomach, small intestine, colon, rectum, liver, gallbladder, pancreas, spleen, kidneys, and bladder.
Abdominal aortic aneurysm
Abdominal aortic aneurysm: A ballooning or widening of the main artery (the aorta) as it courses down through the abdomen. At the point of the aneurysm, the aneurysm usually measures 3 cm or more in diameter. The aneurysm weakens the wall of the aorta and can end in the aorta rupturing with catastrophic consequences. As the diameter of the aorta increases, the chances of an abdominal aortic aneurysm rupturing rise. A measurement of 5 cm is often used to recommend surgery. Persons with AAA tend to be 60 or over. Men are 5 times more likely than women to have an AAA.
Abdominal aorta
Abdominal aorta: The abdominal aorta is the final section of the aorta, the largest artery in the body. It is a continuation of the thoracic aorta. It begins at the diaphragm, and runs down to the point where it ends (by splitting in two to form the common iliac arteries).
The abdominal aorta supplies oxygenated blood to all of the abdominal and pelvic organs and the legs.
Like the other sections of the aorta (the ascending aorta, aortic arch and thoracic aorta), the abdominal aorta is an arbitrary anatomic entity. The aorta is one continuous conduit that arises out of the left ventricle of the heart to carry blood to the body. Nonetheless, the abdominal aorta is a hallowed and convenient subdivision of the aorta.
The abdominal aorta is also known in medical Latin as the aorta abdominalis or the pars abdominalis aortae (under which it is often hidden in standard print medical dictionaries).
The abdominal aorta supplies oxygenated blood to all of the abdominal and pelvic organs and the legs.
Like the other sections of the aorta (the ascending aorta, aortic arch and thoracic aorta), the abdominal aorta is an arbitrary anatomic entity. The aorta is one continuous conduit that arises out of the left ventricle of the heart to carry blood to the body. Nonetheless, the abdominal aorta is a hallowed and convenient subdivision of the aorta.
The abdominal aorta is also known in medical Latin as the aorta abdominalis or the pars abdominalis aortae (under which it is often hidden in standard print medical dictionaries).
Abdominal aneurysm
Abdominal aneurysm: An aneurysm situated within the abdomen (belly). An aneurysm is a localized widening (dilatation) of an artery, vein, or the heart. At the area of an aneurysm, there is typically a bulge and the wall is weakened and may rupture. The word "aneurysm" comes from the Greek "aneurysma" meaning "a widening." An aneurysm may involve the aorta, the largest artery in the body, as it courses down through the abdomen. Because of the great volume of blood flowing under high pressure in the aorta, rupture of an abdominal aortic aneurysm is a surefire catastrophe.
Abdominal
Abdominal: Relating to the abdomen, the belly, that part of the body that contains all of the structures between the chest and the pelvis. The abdomen is separated anatomically from the chest by the diaphragm, the powerful muscle spanning the body cavity below the lungs.
The abdomen includes a host of organs including the stomach, small intestine, colon, rectum, liver, spleen, pancreas, kidneys, appendix, gallbladder, and bladder.
The word "abdomen" has a curious story behind it. It comes from the Latin "abdodere", to hide. The idea was that whatever was eaten was hidden in the abdomen
The abdomen includes a host of organs including the stomach, small intestine, colon, rectum, liver, spleen, pancreas, kidneys, appendix, gallbladder, and bladder.
The word "abdomen" has a curious story behind it. It comes from the Latin "abdodere", to hide. The idea was that whatever was eaten was hidden in the abdomen
acute
Abdomen, acute:The abrupt (acute) onset of abdominal pain. A potential medical emergency, an acute abdomen may reflect a major problem with one of the organs in the abdomen such as the appendix (being inflamed = appendicitis), the gallbladder (inflamed = cholecystitis), the intestine (an ulcer that has perforated), the spleen (that has ruptured), etc. The term "acute abdomen" is medical shorthand. It has nonetheless come into common usage in medical parlance.
Abdomen
Abdomen: The belly, that part of the body that contains all of the structures between the chest and the pelvis. The abdomen is separated anatomically from the chest by the diaphragm, the powerful muscle spanning the body cavity below the lungs.
The abdomen includes a host of organs including the stomach, small intestine, colon, rectum, liver, spleen, pancreas, kidneys, appendix, gallbladder, and bladder.
The word "abdomen" has a curious story behind it. It comes from the Latin "abdodere", to hide. The idea was that whatever was eaten was hidden in the abdomen.
The abdomen includes a host of organs including the stomach, small intestine, colon, rectum, liver, spleen, pancreas, kidneys, appendix, gallbladder, and bladder.
The word "abdomen" has a curious story behind it. It comes from the Latin "abdodere", to hide. The idea was that whatever was eaten was hidden in the abdomen.
Abbreviations
Abbreviations, prescription: A prescription, as is well known, is a physician's order for the preparation and administration of a drug or device for a patient. What may be less well known is that a prescription has several parts:
The superscription (or heading) with the symbol R or Rx which stands for the word Recipe, meaning (in Latin) to take;
The inscription which contains the names and quantities of the ingredients;
The subscription or directions for compounding the drug; and
The signature which is often preceded by the sign s. standing for signa, mark, giving the directions to be marked on the container.
You may see some chicken scrawl marks on a prescription. For example, b.i.d. It means twice (two times) a day and is an abbreviation for "bis in die" which in Latin means, not too surprisingly, twice a day. It is one of a number of hallowed abbreviations of Latin terms that have been traditionally used in prescriptions to specify the frequency with which medicines should be taken.
Some of the abbreviations of terms commonly used in prescriptions with their meanings are:
a.c. = before meals (from "ante cibum," before meals)
ad lib: use as much as one desires (from "ad libitum")
b.i.d. = twice a day
caps = capsules
da or daw = dispense as written
g (or gm or GM) = gram
gtt. = drops (from "guttae," drops)
h. = hour
mg = milligram
ml = milliliter
p.c. = after meals (from "post cibum," after meals)
p.o. = by mouth, orally (from "per os," by mouth)
p.r.n. = when necessary (from "pro re nata," for an occasion that has arisen, as circumstances require, as needed)
q.d. = once a day (from "quaque die," once a day)
q.i.d. = four times a day (from "quater in die," 4 times a day)
q._h.: If a medicine is to be taken every so-many hours (from "quaque," every and the "h" indicating the number of hours)
q.h. = every hour
q.2h. = every 2 hours
q.3h. = every 3 hours
q.4h. = every 4 hours
t.i.d. = three times a day (from "ter in die," 3 times a day)
ut dict. = as directed (from "ut dictum," as directed)
The word "prescription" also comes from the Latin "praescriptus" and is made up of "prae," before + "scribere," to write, so that prescription meant "to write before." This reflected the historic fact that a prescription had traditionally to be written before a drug could be prepared and then administered to a patient.
The superscription (or heading) with the symbol R or Rx which stands for the word Recipe, meaning (in Latin) to take;
The inscription which contains the names and quantities of the ingredients;
The subscription or directions for compounding the drug; and
The signature which is often preceded by the sign s. standing for signa, mark, giving the directions to be marked on the container.
You may see some chicken scrawl marks on a prescription. For example, b.i.d. It means twice (two times) a day and is an abbreviation for "bis in die" which in Latin means, not too surprisingly, twice a day. It is one of a number of hallowed abbreviations of Latin terms that have been traditionally used in prescriptions to specify the frequency with which medicines should be taken.
Some of the abbreviations of terms commonly used in prescriptions with their meanings are:
a.c. = before meals (from "ante cibum," before meals)
ad lib: use as much as one desires (from "ad libitum")
b.i.d. = twice a day
caps = capsules
da or daw = dispense as written
g (or gm or GM) = gram
gtt. = drops (from "guttae," drops)
h. = hour
mg = milligram
ml = milliliter
p.c. = after meals (from "post cibum," after meals)
p.o. = by mouth, orally (from "per os," by mouth)
p.r.n. = when necessary (from "pro re nata," for an occasion that has arisen, as circumstances require, as needed)
q.d. = once a day (from "quaque die," once a day)
q.i.d. = four times a day (from "quater in die," 4 times a day)
q._h.: If a medicine is to be taken every so-many hours (from "quaque," every and the "h" indicating the number of hours)
q.h. = every hour
q.2h. = every 2 hours
q.3h. = every 3 hours
q.4h. = every 4 hours
t.i.d. = three times a day (from "ter in die," 3 times a day)
ut dict. = as directed (from "ut dictum," as directed)
The word "prescription" also comes from the Latin "praescriptus" and is made up of "prae," before + "scribere," to write, so that prescription meant "to write before." This reflected the historic fact that a prescription had traditionally to be written before a drug could be prepared and then administered to a patient.
Abate
Abate: To lessen or decrease. After a boil is lanced, the pus can drain and the pain and tenderness abate. From the French abbatre, to beat down.
Abatement
Abatement: A diminution, decrease or easing. In medicine there may be abatement of pain or any other symptom or sign. In the environment there may abatement in the degree of pollution. See also: Abate.
Smith syndrome
syndrome of congenital malformations (birth defects) characterized by hydrocephalus, cleft palate, and severe arthrogryposis (joint contractures). Other anomalies may include deformed ears, ptosis (drooping) of the eyelids, inability to open the mouth fully, heart defects, and clubfoot. The fingers are thin with absent knuckles, reduced creases over the joints and inability to make a full fist.
The syndrome is inherited as an autosomal dominant trait, transmitted from generation to generation, affecting both males and females. It is named for the American dysmorphologists (birth-defect experts) Jon Aase and David W. Smith.
The syndrome is inherited as an autosomal dominant trait, transmitted from generation to generation, affecting both males and females. It is named for the American dysmorphologists (birth-defect experts) Jon Aase and David W. Smith.
Scott syndrome
Aarskog-Scott syndrome: A syndrome of wide spaced eyes (ocular hypertelorism), front-facing (anteverted) nostrils, a broad upper lip, a malformed ("saddle-bag") scrotum, and laxity of the ligaments resulting in bending back of the knees (genu recurvatum), flat feet, and overly extensible fingers. There are X-linked and autosomal forms of the disease. The gene for the X-linked form has been mapped to chromosome band Xp11.21 and identified as the FGD1 gene.
The disease is named for DJ Aarskog (1928-) and CI Scott, Jr. (1934-), Norwegian and American pediatricians, who described it in 1970 and 1971. It is also known as Aarskog syndrome, faciodigitogenital dysplasia, and faciogenital dysplasia
The disease is named for DJ Aarskog (1928-) and CI Scott, Jr. (1934-), Norwegian and American pediatricians, who described it in 1970 and 1971. It is also known as Aarskog syndrome, faciodigitogenital dysplasia, and faciogenital dysplasia
Aarskog syndrome
Aarskog-Scott syndrome: A syndrome of wide spaced eyes (ocular hypertelorism), front-facing (anteverted) nostrils, a broad upper lip, a malformed ("saddle-bag") scrotum, and laxity of the ligaments resulting in bending back of the knees (genu recurvatum), flat feet, and overly extensible fingers. There are X-linked and autosomal forms of the disease. The gene for the X-linked form has been mapped to chromosome band Xp11.21 and identified as the FGD1 gene.
The disease is named for DJ Aarskog (1928-) and CI Scott, Jr. (1934-), Norwegian and American pediatricians, who described it in 1970 and 1971. It is also known as Aarskog syndrome, faciodigitogenital dysplasia, and faciogenital dysplasia.
The disease is named for DJ Aarskog (1928-) and CI Scott, Jr. (1934-), Norwegian and American pediatricians, who described it in 1970 and 1971. It is also known as Aarskog syndrome, faciodigitogenital dysplasia, and faciogenital dysplasia.
adenine
A (adenine): In genetics, A stands for adenine, one member of the A-T (adenine-thymine) base pair in DNA. The other base pair in DNA is G-C (guanine-cytosine).
Each base pair forms a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In DNA base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.
Adenine is also one of the bases in RNA. There it always pairs with uracil (U). The base pairs in RNA are therefore A-U and G-C.
Each base pair forms a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In DNA base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.
Adenine is also one of the bases in RNA. There it always pairs with uracil (U). The base pairs in RNA are therefore A-U and G-C.
Monday, May 18, 2009
Absorb
Absorb: 1. To take something in, as through the skin or the intestine.2. To react with radiation and reduce it in intensity, as with a dose of radiation or transmitted light
Absinthism
Absinthism: The disorder associated with the habitual abuse of absinthe. The symptoms included hallucinations, sleeplessness, tremors, and convulsions. There has been debate over whether absinthism was due to absinthe or the alcohol contained therein. For more information,
Absinthe
Absinthe: Once a major medical hazard, absinthe is an emerald-green liqueur flavored with extracts of the wormwood plant, licorice and aromatic flavorings in a alcohol base. Absinthe was manufactured, commercialized and popularized in France in the late 1700s by Henri-Louis Pernod. It became an extremely popular and addictive drink. Among the famous figures who made absinthe a symbol of decadence were the writer Oscar Wilde, the poet Charles Baudelaire, and the artists Edouard Manet, Vincent Van Gogh, Henri de Toulouse-Lautrec and Pablo Picasso.
The first important medical research on absinthe was initiated in 1864 by a psychiatrist, Valentin Jacques Joseph Magnan, who exposed a veritable Noah's arkful of animals to wormwood oil (the essence of absinthe) and alcohol (the base of absinthe). He put cats, rabbits, and guinea pigs under an individual glass case next to a saucer of either wormwood oil or alcohol. The animals that breathed the alcohol fumes became drunk while those that inhaled the vapors of wormwood had epileptic seizures, reported Dr. Magnan in the medical journal The Lancet.
Prolonged drinking of absinthe causes convulsions, blindness, hallucinations, and mental deterioration. Absinthe has been banned but something of its taste of absinthe is still available in such drinks as ouzo in Greece and in France, pastis, long considered "the mother's milk of Provence."
The first important medical research on absinthe was initiated in 1864 by a psychiatrist, Valentin Jacques Joseph Magnan, who exposed a veritable Noah's arkful of animals to wormwood oil (the essence of absinthe) and alcohol (the base of absinthe). He put cats, rabbits, and guinea pigs under an individual glass case next to a saucer of either wormwood oil or alcohol. The animals that breathed the alcohol fumes became drunk while those that inhaled the vapors of wormwood had epileptic seizures, reported Dr. Magnan in the medical journal The Lancet.
Prolonged drinking of absinthe causes convulsions, blindness, hallucinations, and mental deterioration. Absinthe has been banned but something of its taste of absinthe is still available in such drinks as ouzo in Greece and in France, pastis, long considered "the mother's milk of Provence."
Absenteeism
Definition of Absenteeism
Absenteeism: The frequent absence from work or other duty without good reason
Absenteeism: The frequent absence from work or other duty without good reason
Absent eye
Absent eye: Also called anophthalmia, a congenital malformation (birth defect) of the globe.
Anophthalmia refers, strictly speaking, to absence of the globe and ocular tissue from the orbit. However, in most cases of anophthalmia, CT scans show some remnants of the globe, indicating they represent severe microphthalmia (small eyes).
Anophthalmia/microphthalmia may involve one or both eyes. It may occur in isolation with no associated malformations or it may be part of a multiple congenital malformation syndrome as, for example, the congenital rubella syndrome, the triploidy syndrome (due to the presence of 69 chromosomes), the trisomy 13 syndrome (Patau syndrome, due to an extra chromosome 13), and the Wolf-Hirschorn syndrome (which is due to deletion of part of the short arm of chromosome 4).
Anophthalmia comes from the Greek an-, absence + ophthalmos, eye + absence of the eye.
Anophthalmia refers, strictly speaking, to absence of the globe and ocular tissue from the orbit. However, in most cases of anophthalmia, CT scans show some remnants of the globe, indicating they represent severe microphthalmia (small eyes).
Anophthalmia/microphthalmia may involve one or both eyes. It may occur in isolation with no associated malformations or it may be part of a multiple congenital malformation syndrome as, for example, the congenital rubella syndrome, the triploidy syndrome (due to the presence of 69 chromosomes), the trisomy 13 syndrome (Patau syndrome, due to an extra chromosome 13), and the Wolf-Hirschorn syndrome (which is due to deletion of part of the short arm of chromosome 4).
Anophthalmia comes from the Greek an-, absence + ophthalmos, eye + absence of the eye.
Abscess
Abscess: A local accumulation of pus anywhere in the body. The following are some examples of abscesses:
A skin abscess is better known as a common boil;
A peritonsillar abscess is a persistent collection of pus behind the tonsils; and
A perianal abscess is a pool of pus that forms next to the anus, often causing considerable tenderness and swelling in that area and pain on sitting down and on defecating.
A skin abscess is better known as a common boil;
A peritonsillar abscess is a persistent collection of pus behind the tonsils; and
A perianal abscess is a pool of pus that forms next to the anus, often causing considerable tenderness and swelling in that area and pain on sitting down and on defecating.
Abs
Abs: Commonly used slang for the abdominal muscles, the muscles running up and down in the abdominal wall. The "abs" contain the rectus abdominus muscle, "rectus" meaning straight
Abruption
Abruption: A sudden breaking off or away. Abruption of the placenta (abruptio placentae) is the premature separation of the placenta from the wall of the uterus, a potentially very serious situation for the mother and baby.
Abruptio
Abruptio (abruptio placentae): Premature separation of the placenta from the wall of the uterus. Abruption is a potentially serious problem both for the mother and baby
Abrin
Abrin: A phytotoxin (plant poison) found in the seeds of a plant called the rosary pea or jequirity pea. These seeds are red with a black spot covering one end. Abrin is similar to ricin, a toxin that is also found in the seeds of a plant (the castor bean plant), although abrin is much more poisonous than ricin. Abrin can be made in the form of a powder, a mist, or a pellet, or it can be dissolved in water. Powdered abrin is yellowish-white in color. Abrin is a stable substance, meaning that it can last for a long time in the environment despite extreme conditions such as very hot or very cold temperatures. The seeds of the rosary pea have been used to make beaded jewelry, which can lead to abrin poisoning if the seeds are swallowed. Abrin is currently of concern as a possible agent of bioterrorism.
Abrin works by getting inside the cells of a person's body and preventing the cells from making the proteins they need. Without the proteins, cells die. Eventually this is harmful to the whole body, and death may occur. The major symptoms of abrin poisoning depend on the route of exposure and the dose received, though many organs may be affected in severe cases.
Initial symptoms of abrin poisoning by inhalation may occur within 8 hours of exposure. The likely symptoms are respiratory distress (difficulty breathing), fever, cough, nausea, and tightness in the chest. Heavy sweating may follow as well as fluid building up in the lungs (pulmonary edema). This would make breathing even more difficult, and the skin might turn blue. Excess fluid in the lungs would be diagnosed by x-ray or by listening to the chest with a stethoscope. Finally, low blood pressure and respiratory failure may occur, leading to death.
Following ingestion of abrin, initial symptoms may occur in less than 6 hours but usually are delayed for 1 to 3 days. Symptoms would include vomiting and diarrhea that may become bloody. Severe dehydration may be the result, followed by low blood pressure. Other signs or symptoms may include hallucinations, seizures, and blood in the urine. Within several days, the person's liver, spleen, and kidneys might stop working, and the person could die.
Abrin in the powder or mist form can cause redness and pain of the skin and the eyes. Death from abrin poisoning could take place within 36 to 72 hours of exposure, depending on the route of exposure (inhalation, ingestion, or injection) and the dose received. If death has not occurred in 3 to 5 days, the victim usually recovers.
Because no antidote exists for abrin, the most important factor is avoiding abrin exposure in the first place. If exposure cannot be avoided, the most important factor is then getting the abrin off or out of the body as quickly as possible. Abrin poisoning is treated by giving victims supportive medical care to minimize the effects of the poisoning. The types of supportive medical care would depend on several factors, such as the route by which victims were poisoned (that is, whether poisoning was by inhalation, ingestion, or skin or eye exposure). Care could include such measures as helping victims breathe, giving them intravenous fluids (fluids given through a needle inserted into a vein), giving them medications to treat conditions such as seizure and low blood pressure, flushing their stomachs with activated charcoal (if the abrin has been very recently ingested), or washing out their eyes with water if their eyes are irritated.
Abrin works by getting inside the cells of a person's body and preventing the cells from making the proteins they need. Without the proteins, cells die. Eventually this is harmful to the whole body, and death may occur. The major symptoms of abrin poisoning depend on the route of exposure and the dose received, though many organs may be affected in severe cases.
Initial symptoms of abrin poisoning by inhalation may occur within 8 hours of exposure. The likely symptoms are respiratory distress (difficulty breathing), fever, cough, nausea, and tightness in the chest. Heavy sweating may follow as well as fluid building up in the lungs (pulmonary edema). This would make breathing even more difficult, and the skin might turn blue. Excess fluid in the lungs would be diagnosed by x-ray or by listening to the chest with a stethoscope. Finally, low blood pressure and respiratory failure may occur, leading to death.
Following ingestion of abrin, initial symptoms may occur in less than 6 hours but usually are delayed for 1 to 3 days. Symptoms would include vomiting and diarrhea that may become bloody. Severe dehydration may be the result, followed by low blood pressure. Other signs or symptoms may include hallucinations, seizures, and blood in the urine. Within several days, the person's liver, spleen, and kidneys might stop working, and the person could die.
Abrin in the powder or mist form can cause redness and pain of the skin and the eyes. Death from abrin poisoning could take place within 36 to 72 hours of exposure, depending on the route of exposure (inhalation, ingestion, or injection) and the dose received. If death has not occurred in 3 to 5 days, the victim usually recovers.
Because no antidote exists for abrin, the most important factor is avoiding abrin exposure in the first place. If exposure cannot be avoided, the most important factor is then getting the abrin off or out of the body as quickly as possible. Abrin poisoning is treated by giving victims supportive medical care to minimize the effects of the poisoning. The types of supportive medical care would depend on several factors, such as the route by which victims were poisoned (that is, whether poisoning was by inhalation, ingestion, or skin or eye exposure). Care could include such measures as helping victims breathe, giving them intravenous fluids (fluids given through a needle inserted into a vein), giving them medications to treat conditions such as seizure and low blood pressure, flushing their stomachs with activated charcoal (if the abrin has been very recently ingested), or washing out their eyes with water if their eyes are irritated.
Abrasion
Abrasion: An abrasion or "excoriation" is a wearing away of the upper layer of skin as a result of applied friction force. In dentistry an "abrasion" is the wearing away of the tooth substance
Abraham man
Abraham-man: Also abram-man. One of a class of beggars who once wandered over England after the dissolution of the religious houses in the 16th century, pretending lunacy for the sake of obtaining alms.
To sham Abraham (or sham Abram) now means to feign sickness, to fake illness.
To sham Abraham (or sham Abram) now means to feign sickness, to fake illness.
ABR test
ABR test: Auditory brainstem response test. A test for hearing and brain (neurological) functioning. ABR may be used in the evaluation of:
Hearing integrity (and neurologic normalcy) in infants and young children.
Neurologic integrity (and hearing) in patients who are comatose, unresponsive, or impaired due to a stroke, an acoustic neuroma (tumor on the hearing nerve), Meniere's disease, etc.
The ABR test involves attaching electrodes to the head to record electrical activity from the auditory nerve (the hearing nerve) and other parts of the brain. Also known as brainstem auditory evoked potentials (BAEP).
Hearing integrity (and neurologic normalcy) in infants and young children.
Neurologic integrity (and hearing) in patients who are comatose, unresponsive, or impaired due to a stroke, an acoustic neuroma (tumor on the hearing nerve), Meniere's disease, etc.
The ABR test involves attaching electrodes to the head to record electrical activity from the auditory nerve (the hearing nerve) and other parts of the brain. Also known as brainstem auditory evoked potentials (BAEP).
Abortive polio
Abortive polio: Abortive polio is a minor illness. It accounts for 80-90% of clinically apparent cases of polio infection, chiefly in young children. It does not involve the CNS. The usual symptoms are slight fever, malaise, headache, sore throat and vomiting which hit 3-5 days after exposure to the polio virus. Full recovery occurs in 24-72 hours. There are no permanent disabilities of any kind.
Polio as a major illness is in contrast to abortive polio. Symptoms appear usually with no sign of a prior illness 7-14 days after exposure to the virus, particularly in older children and adults, and may include fever, severe headache, stiff neck and back, deep muscle pain, and sometimes areas of hyperesthesia (increased sensation) and paresthesia (altered sensation). There may be no further progression from this picture of viral meningitis (called "aseptic" meningitis) or there be loss of tendon reflexes and weakness or paralysis of muscle groups.
Polio can thus take one of two main avenues: that of minor ("abortive") illness or that of major illness. And polio as a major illness can then take one of two branching roads: that of aseptic meningitis without paralysis or that of paralytic polio.
In abortive polio, recovery is complete. Recovery is also complete in polio with only aseptic meningitis. In paralytic polio, about 50% of patients recover with no residual paralysis, about 25% are left with mild disabilities, and the remaining patients have severe permanent disability.
The word "abortive" here means "tending to cut short" so that abortive polio is polio cut short.
Polio as a major illness is in contrast to abortive polio. Symptoms appear usually with no sign of a prior illness 7-14 days after exposure to the virus, particularly in older children and adults, and may include fever, severe headache, stiff neck and back, deep muscle pain, and sometimes areas of hyperesthesia (increased sensation) and paresthesia (altered sensation). There may be no further progression from this picture of viral meningitis (called "aseptic" meningitis) or there be loss of tendon reflexes and weakness or paralysis of muscle groups.
Polio can thus take one of two main avenues: that of minor ("abortive") illness or that of major illness. And polio as a major illness can then take one of two branching roads: that of aseptic meningitis without paralysis or that of paralytic polio.
In abortive polio, recovery is complete. Recovery is also complete in polio with only aseptic meningitis. In paralytic polio, about 50% of patients recover with no residual paralysis, about 25% are left with mild disabilities, and the remaining patients have severe permanent disability.
The word "abortive" here means "tending to cut short" so that abortive polio is polio cut short.
Abortive
Abortive: The word "abortive" has a number of meanings including prematurely born; fruitless or unsuccessful; imperfectly formed or developed; tending to cut short.
In everyday language, the sense of "abortive" to mean prematurely born, as "an abortive child," is largely obsolete today. The main meaning of "abortive" in ordinary English is fruitless or unsuccessful, as an "abortive enterprise" or an "abortive effort."
In biology, "abortive" means imperfectly formed or developed or rudimentary as, an "abortive organ."
In medicine, "abortive" has two meanings: one, causing abortion, as an "abortive medicine," is rarely used nowadays; the other meaning, that of tending to cut short is quite commonly used in medicine, as in the "abortive treatment of typhoid fever" or "abortive polio": polio cut short.
In everyday language, the sense of "abortive" to mean prematurely born, as "an abortive child," is largely obsolete today. The main meaning of "abortive" in ordinary English is fruitless or unsuccessful, as an "abortive enterprise" or an "abortive effort."
In biology, "abortive" means imperfectly formed or developed or rudimentary as, an "abortive organ."
In medicine, "abortive" has two meanings: one, causing abortion, as an "abortive medicine," is rarely used nowadays; the other meaning, that of tending to cut short is quite commonly used in medicine, as in the "abortive treatment of typhoid fever" or "abortive polio": polio cut short.
Abortifacient
Abortifacient: A substance that causes pregnancy to end prematurely and causes an abortion
Abortion
Abortion: In medicine, an abortion is the premature exit of the products of conception (the fetus, fetal membranes, and placenta) from the uterus. It is the loss of a pregnancy and does not refer to why that pregnancy was lost.
A spontaneous abortion is the same as a miscarriage. The miscarriage of 3 or more consecutive pregnancies is termed habitual abortion.
A spontaneous abortion is the same as a miscarriage. The miscarriage of 3 or more consecutive pregnancies is termed habitual abortion.
Abnormal
Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant
Ablation
Ablation: Removal or excision. Ablation is usually carried out surgically. For example, surgical removal of the thyroid gland (a total thyroidectomy) is ablation of the thyroid. The word ablation comes from the Latin ablatum meaning to carry away.
Historically, the word ablation once had mainly a general meaning so that in 1671 the ablation (removal) of a disease was a matter for consideration. But by 1846 "ablation" had taken on a specifically surgical edge and today it applies principally to the surgical removal of any part of the body.
Historically, the word ablation once had mainly a general meaning so that in 1671 the ablation (removal) of a disease was a matter for consideration. But by 1846 "ablation" had taken on a specifically surgical edge and today it applies principally to the surgical removal of any part of the body.
Ablate
Ablate: To remove. A tumor may be ablated. To ablate the thyroid gland is to remove it. The word "ablation" came from the Latin "ablatum" meaning to carry away.
In 1671 the ablation (removal) of a disease was a matter for consideration. But by 1846 "ablation" had taken on a specifically surgical edge and today it applies principally to the surgical removal of any part of the body.
In 1671 the ablation (removal) of a disease was a matter for consideration. But by 1846 "ablation" had taken on a specifically surgical edge and today it applies principally to the surgical removal of any part of the body.
Sunday, April 19, 2009
Accoucheuse
Accoucheuse: French for a woman who is an obstetrician (a physician skilled in the art and science of managing pregnancy, labor and the time after delivery) or a midwife (today a non-physician trained to assist a woman during childbirth). The ending "-euse" is feminine and indicates that the accoucheuse is a woman
Accoucheur
Accoucheur: French for a male obstetrician, a physician skilled in the art and science of managing pregnancy, labor and the puerperium (the time after delivery).
Accommodation
Accommodation: In medicine, the ability of the eye to change its focus from distant to near objects (and vice versa). This process is achieved by the lens changing its shape.
Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies. It is the process of adjusting the focal length of a lens.
Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies. It is the process of adjusting the focal length of a lens.
Acclimatization to altitude
Acclimatization to altitude: The main cause of altitude sickness is going too high too fast. Given time, the body can adapt to the decrease in oxygen concentration at a specific altitude, process known as acclimatization.
To acclimatize, a number of changes take place in the body occur to allow it to operate with decreased oxygen:
The depth of respiration increases;
The pressure in the pulmonary arteries increases, forcing blood into portions of the lung which are normally not used at sea level;
We make more red blood cells to carry oxygen;
We make more of a specific substance (called 2,4-DPG)that facilitates the release of oxygen from hemoglobin to the body tissues.
Acclimatization generally takes 1 to 3 days at a given altitude. For example, if a person hikes to 10,000 feet (3,048 meters) and spends several days at that altitude, their body acclimatizes to 10,000 feet (3,048 meters). If the person then climbs to 12,000 feet (3,658 meters), the body needs to acclimatize once again and it takes another 1 to 3 days.
To acclimatize, a number of changes take place in the body occur to allow it to operate with decreased oxygen:
The depth of respiration increases;
The pressure in the pulmonary arteries increases, forcing blood into portions of the lung which are normally not used at sea level;
We make more red blood cells to carry oxygen;
We make more of a specific substance (called 2,4-DPG)that facilitates the release of oxygen from hemoglobin to the body tissues.
Acclimatization generally takes 1 to 3 days at a given altitude. For example, if a person hikes to 10,000 feet (3,048 meters) and spends several days at that altitude, their body acclimatizes to 10,000 feet (3,048 meters). If the person then climbs to 12,000 feet (3,658 meters), the body needs to acclimatize once again and it takes another 1 to 3 days.
Accessory placenta
Accessory placenta: An extra placenta separate from the main placenta. Also called a succenturiate or supernumerary placenta. The placenta is the organ joining the mother and fetus, the organ that permits the provision of oxygen and nutrients to the fetus and the release of carbon dioxide and waste products from the fetus to the mother. The word "placenta" means a flat cake. The main placenta is disk-shaped and at full term measures about 7 inches (18 cm) in diameter and a bit less than 2 inches (4 cm) thick. The upper surface of the placenta is smooth while the under surface is rough. The placenta and the fetal membranes are the afterbirth.
Accessory-neuropathy
Accessory neuropathy: Disease of the accessory nerve which is the eleventh cranial nerve. The accessory nerve supplies the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is in the front of the neck and turns the head. The trapezius muscle moves the scapula (the wingbone), turns the face to the opposite side, and helps pull the head back.
Damage to the accessory nerve can be confined to the accessory nerve or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy can sometimes occur and recur for unknown reasons. Most patients recover.
Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.
Damage to the accessory nerve can be confined to the accessory nerve or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy can sometimes occur and recur for unknown reasons. Most patients recover.
Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.
Accessory-nerve
Accessory nerve: The eleventh cranial nerve, which emerges from the skull and receives an additional (accessory) root from the upper part of the spinal cord. It supplies the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is in the front of the neck and turns the head. The trapezius muscle moves the scapula (the wingbone), turns the face to the opposite side, and helps pull the head back. The accessory nerve is so-called because, although it arises in the brain, it receives an additional (accessory) root from the upper part of the spinal cord.
Damage to the accessory nerve can be isolated (confined to the accessory nerve) or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy (nerve disease) can sometimes occur and recur for unknown reasons. Most patients recover.
Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.
Damage to the accessory nerve can be isolated (confined to the accessory nerve) or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy (nerve disease) can sometimes occur and recur for unknown reasons. Most patients recover.
Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.
Accessory dwelling unit
Accessory dwelling unit: (ADU) A separate housing arrangement within a single-family home. The ADU is defined by Medicare as a complete living unit and includes a private kitchen and bath.
Accessory digestive organ
Accessory digestive organ: An organ that helps with digestion but is not part of the digestive tract. The accessory digestive organs are the tongue, salivary glands, pancreas, liver, and gallbladder.
Accessory
Accessory: Additional, extra, supplementary, subsidiary to the main thing. An accessory digestive organ is an organ that helps with digestion but is not part of the digestive tract. The accessory nerve is so-called because it receives an additional (accessory) root from the upper part of the spinal cord. An accessory placenta is an extra placenta separate from the main placenta.
Accessibility of services
Accessibility of services: The ability to get medical care and services when needed.
Access
Access: 1. In general, a means of approaching something. 2. In health care, the opportunity or right to receive health care. 3. In dialysis, the point on the body where a needle or catheter is inserted to gain entry to the bloodstream.
Acceptable daily intake
Acceptable daily intake: Estimate of the amount of a substance in food or drinking water, expressed on a body mass basis (usually mg/kg body weight), which can be ingested daily over a lifetime by humans without appreciable health risk. For calculation of the daily intake per person, a standard body mass of 60 kg is used. The acceptable daily intake is normally used for food additives (tolerable daily intake is used for contaminants). Abbreviated ADI.
Acaricide
Acaricide: An agent, usually a chemical, that kills mites. This class of pesticides is large and includes antibiotic acaricides, carbamate acaricides, formamidine acaricides, mite growth regulators, organophosphate acaricides, and many others. From the Latin acarus, a mite + -cide, to kill.
Acapnia
Acapnia: Less than the normal level of carbon dioxide in the blood. The opposite of hypercapnia. The origin of the word "acapnia" is curious. It comes from the Greek "a-" meaning "without" + "kapnos" meaning "smoke" so acapnia literally means "smokeless" referring to carbon dioxide which is a principal part of smoke.
Acanthosis nigricans
Acanthosis nigricans: A skin condition characterized by dark thickened velvety patches, especially in the folds of skin in the axilla (armpit), groin and back of the neck. The condition is complex. It can occur with endocrine diseases such as Cushing disease, tumors of the pituitary, and diabetes mellitus. It is common in people who have insulin resistance -- whose body is not responding correctly to the insulin that they make in their pancreas. Acanthosis nigricans also occurs with underlying malignancies (especially carcinomas of the vicera), administration of certain drugs, and as a genetic disorder inherited in an autosomal dominant manner.
Acanthamoeba
Acanthamoeba: A microscopic organism, an amoeba, found in soil, dust and fresh water (lakes, rivers, hot springs and hot tubs). Acanthamoeba also occur in brackish water and sea water as well as in heating, venting, and air conditioner units, humidifiers, and dialysis units.
Acanthamoeba can enter the skin through a cut, wound, or through the nostrils and, once inside the body, can travel to the lungs and through the bloodstream to other parts of the body, especially to the central nervous system (the brain and spinal cord). Through improper storage, handling, and disinfection of contact lenses, Acanthamoeba can enter the eye and there cause infection.
A particularly dire infection caused by Acanthamoeba called granulomatous amebic encephalitis is characterized by headache, stiff neck, nausea, vomiting, confusion, loss of balance, seizures, and coma that can progress over several weeks and end in death. Acanthamoeba infections occur more frequently in people with compromised immune systems and the chronically ill. Eye and skin infections are generally treatable while infections of the brain are almost always fatal.
Acanthamoeba can enter the skin through a cut, wound, or through the nostrils and, once inside the body, can travel to the lungs and through the bloodstream to other parts of the body, especially to the central nervous system (the brain and spinal cord). Through improper storage, handling, and disinfection of contact lenses, Acanthamoeba can enter the eye and there cause infection.
A particularly dire infection caused by Acanthamoeba called granulomatous amebic encephalitis is characterized by headache, stiff neck, nausea, vomiting, confusion, loss of balance, seizures, and coma that can progress over several weeks and end in death. Acanthamoeba infections occur more frequently in people with compromised immune systems and the chronically ill. Eye and skin infections are generally treatable while infections of the brain are almost always fatal.
Saturday, April 18, 2009
Abstemious
Abstemious: Marked by restraint, especially in the consumption of food or alcohol.
From the Latin prefix "abs-," meaning "from" or "away," and the Latin noun "temetum," meaning "intoxicating drink."
From the Latin prefix "abs-," meaning "from" or "away," and the Latin noun "temetum," meaning "intoxicating drink."
Abstinence
Abstinence: The voluntary self-denial of food, drink, or sex. Today, abstinence most commonly refers to denial of one's sexual activity.
Absorption
Absorption: Uptake. In the biomedical sciences, absorption has diverse specific meanings.
In the body, absorption is the process whereby a cell, tissue or organ takes up a substance.
In the intestinal tract, absorption is the uptake of food (or other substances) from the digestive tract.
In radiology, absorption refers to the taking up of energy by matter with which the radiation interacts.
In immunology, absorption is the process by which an antibody or antigen is used to remove a corresponding antigen or antibody from a mixture.
In the body, absorption is the process whereby a cell, tissue or organ takes up a substance.
In the intestinal tract, absorption is the uptake of food (or other substances) from the digestive tract.
In radiology, absorption refers to the taking up of energy by matter with which the radiation interacts.
In immunology, absorption is the process by which an antibody or antigen is used to remove a corresponding antigen or antibody from a mixture.
Absence seizure
Absence seizure: A seizure that takes the form of a staring spell. The person suddenly seems to be "absent." An absence seizure involves a brief loss of awareness, which can be accompanied by blinking or mouth twitching. Absence seizures have a very characteristic appearance on an electroencephalogram (EEG).
Also called a petit mal seizure
Also called a petit mal seizure
Abiotrophy
Abiotrophy: Loss of function or degeneration for reasons unknown. For example, cerebellar abiotrophy may affect coordination while cone-rod abiotrophy may cause blindness at birth
Aberration
Aberration: (1) A deviation or irregularity. For example, a chromosome aberration is a deviation from the normal chromosome number or the normal chromosome structure. In this sense, aberration is also synonymous with deflection, departure, divergence, diversion, turning. (2) A mental aberration is a significant deviation from normal mental activity. In this sense, aberration is synonymous with mental derangement, mental illness, psychopathy.
Abiotic
Abiotic: 1. Not associated with living organisms.2. Anything in the environment incapable of life, such as the soil or weather.3. Incompatible with life or antagonist to it.Also called abiological.
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