R: Commonly used
abbreviation for respiration(s). For example, in a medical
chart, you might see scrawled "BP90/60 T98.6 HR 60/reg R15",
which is short hand signifying that the blood pressure is
90/60 mm Hg, the temperature (T) is 98.6 degrees Fahrenheit,
the heart rate (HR) is 60/min and regular, and the
respirations ® 15/min. (This example would be entirely normal
for an adult or older child).
r: Symbol for a ring chromosome, a structurally abnormal
chromosome in which the end of each chromosome arm has been
lost and the broken arms have been reunited in ring formation.
Rabid: Having contracted the rabies virus. (Whereas a sports fan
can be rabid without being physically sick, in medicine a rabid
individual has rabies.)
Rabies: Virus disease of warmblooded animals transmitted to
people by a bite (or other means). Animals capable of carrying
rabies include dogs, bats, cats, racoons and skunks. In Latin,
rabies means madness or rage.
Rad: A unit of energy. A rad is like a roentgen ® but is based
on absorbed energy from an ionizing or nonionizing source.
Radial: In anatomy, radial pertains to the radius, the smaller
of the two bones on the thumb's side of the forearm. (The bigger
one is the ulna). The word radius comes unchanged from the Latin
meaning a spoke in a wheel which this bone was thought to
resemble. The word radiation is derived from the same Latin
Radial aplasia-thrombocytopenia syndrome: Aplasia (absence) of
the Radius (the long bone on the thumb-side of the forearm) and
Thrombocytopenia (low blood platelets) are key features
characterizing this syndrome. There is phocomelia (flipper-limb)
with the thumbs always present. The fibula (the smaller bone in
the lower leg) is often absent. The risk of bleeding from too
few platelets is high in early infancy but lessens with age. The
condition is inherited in an autosomal recessive trait with one
gene (on a non-sex chromosome) coming from each parent to the
child affected with the disease. Alternative names include
thrombocytopenia-absent radius syndrome, TAR syndrome, and
Radiation: The word radiation is derived from the Latin word
radius meaning a spoke in a wheel. The same Latin word radius
was given by the Romans to the smaller of the two bones in the
forearm since it was thought to look like a spoke in a wheel.
Radiation fibrosis: The formation of scar tissue as a result of
radiation therapy to the lung.
Radiation oncologist: A doctor who specializes in using
radiation to treat cancer.
Radiation therapy: Radiation therapy is the use of special high
energy x-ray beams to kill rapidly growing cells, such as cancer
cells. It is a generally a painless treatment and is given in an
outpatient setting without the need for hospitalization.
Radical cystectomy: Surgery to remove the bladder as well as
nearby tissues and organs.
Radical, free: In biochemistry, it is a group of atoms bonded
together into an entity that is extremely reactive and
shortlived. (A free radical is not a political extremist on
Radical mastectomy, modified: Breast cancer treatment involving
removal of the breast, lymph nodes (the "glands") in the armpit
and associated skin and subcutaneous tissue. It differs from
total radical mastectomy in that the pectoral (chest) muscles
Radical mastectomy, total: Breast cancer treatment involving
removal of the breast, the pectoral (chest) muscles, lymph nodes
(the "glands") in the armpit and associated skin and
Radical surgery: Surgery designed to remove all possible
diseased tissue, for example, all possible tumor tissue.
Radicle: Radicle is the diminutive derived from the Latin radix
meaning root so it is therefore a little root. A nerve radicle
is the smallest extension of a nerve.
Radiculitis: Inflammation of the root of a spinal nerve. The
Latin radix means root.
Radioactive: Giving off radiation.
Radioactive iodine: Iodine that gives off radiation. See
Radioallergosorbent test (RAST): An allergy test done on a
sample of blood. The aim with RAST, as with skin tests, is to
check for allergic sensitivity to specific substances. RAST
stands for RadioAllergoSorbent Test.
Radiograph: Medical term for an X-ray. A film produced by X-ray.
Radiography: Film records (radiographs) of internal structures
of the body. Radiography is made possible by X-rays (or gamma
rays) passing through the body to act on a specially sensitized
Radioimmunoassay: A very sensitive, specific laboratory test
(assay) using radiolabeled (and unlabeled) substances in an
immunological (antibody-antigen) reaction.
Radioinsensitive: Not sensitive to X-rays and other forms of
radiant energy. For example, a tumor may unfortunately be
radioinsensitive. The opposite of radiosensitive.
Radioiodine: A radioactive isotope of iodine. (An isotope is an
alternate version of a chemical element that has a different
atomic mass). Radioiodine can be used in diagnostic tests as
well as in radiotherapy of the thyroid. For hyperthyroidism,
radioiodine is administered in capsule form on a one-time basis.
It directly radiates thyroid tissues thereby destroying them. It
takes 8-12 weeks for the thyroid to become euthyroid (normal)
after treatment. The majority of patients undergoing this
treatment eventually become hypothyroid, which is easily treated
using thyroid hormones (levothyroxine). Radioiodine is
contraindicated during pregnancy and breast feeding.
Radioisotope: A radioactive isotope. (An isotope is an alternate
version of a chemical element that has a different atomic mass).
Radiologic: Having to do with radiology.
Radiology: The science of radiation, both ionizing (like X-ray)
and nonionizing (like ultrasound), applied to the diagnosis and
treatment of disease. Radiology is also known as roentgenology
after Wilhelm Conrad Roentgen who discovered X-rays in 1895.
Radiolucent: X-rays shine right through things that are
radiolucent ( lucere in Latin means to shine). Radiolucent
structures appear black on exposed X-ray film.
Radiopaque: X-rays cannot penetrate things that are radiopaque
(opaque to X-ray). Radiopaque structures appear white on exposed
Radionuclide scan: An exam that produces pictures (scans) of
internal parts of the body. The patient is given an injection or
swallows a small amount of radioactive material. A machine
called a scanner then measures the radioactivity in certain
Radiosensitive: Sensitive to X-rays and other forms of radiant
energy. For example, a tumor may be radiosensitive. The opposite
Radiotherapy: The treatment of disease with ionizing radiation.
Synonymous with radiation therapy.
Radium: The celebrated radioactive element discovered by Marie
and Pierre Curie in 1898.
Radius: In anatomy, the radius is the smaller of the the two
bones on the thumb's side of the forearm. (The bigger one is the
ulna). The word radius comes unchanged from the Latin meaning a
spoke in a wheel which this bone was thought to resemble. The
word radiation is derived from the same Latin word, radius.
Radon: A radioactive element formed as a gas during the
breakdown of radium.
Ragweed: Any of a number of weedy composite herbs that produce a
pollen that is a frequent cause of allergies. Of all allergy
sufferers in the United States, 75% are allergic to ragweed.
Rale: A type of abnormal lung sound heard through a stethescope.
Rales may be sibilant (whistling), dry (crackling) or wet (more
sloshy) depending on the amount and density of fluid refluxing
back and forth in the air passages. The word rale is a straight
steal from the French rale (minus the circumflex accent over the
a). In French, a rale was originally restricted to the death
rattle (le rale de mort). After Laennec invented the stethescope
in France in 1815, he borrowed the word rale to apply it to the
less ominous, albeit still abnormal, lung sounds he heard
through his newfangled instrument.
Ramus: A standard medical dictionary contains over 13 pages full
of entries to the word ramus. Why? Because ramus in Latin means
a branch and all sorts of anatomic items such as blood vessels
and nerves quite naturally have branches. So, for example,
medicine is plagued with the likes of the ramus acetabularis
arteriae circumflexae femoris medialis which is simply the
branch of an artery that goes to the acetabulum (the socket) of
the hip joint.
Ramus of the mandible: The mandible (the lower jaw bone) is
shaped like a horseshoe. The back parts of the horseshoe that
stick up are the two ramuses, or more properly, the rami of the
Random mating: Totally haphazard mating with no regard to the
genetic makeup (genotype) of the mate so that any sperm has an
equal chance of fertilizing any egg. This rarely, if ever,
occurs but the concept is impoortant in population genetics.
Also called panmixus.
Range: In medicine (and statistics), the range is the difference
between the lowest and highest numerical values. For example, if
premature infants are born weighing 2, 3, 4, 4, and 5 pounds,
the range of their birth weights is 2-5 pounds.
Range, normal: Normal results can fall outside the normal range.
By convention, the normal range is set to cover ninety-five
percent (95%) of values from a normal population. Five percent
(5%) of normal results therefore fall outside the normal range.
Range of motion: The range through which a joint can be moved,
usually its range of flexion and extension. Due to an injury,
the knee may for example lack 10 degrees of full extension.
Rash: Breaking out (eruption) of the skin. Medically, a rash is
referred to as an exanthem.
RAST: An allergy test done on a sample of blood. The aim with
RAST, as with skin tests, is to check for allergic sensitivity
to specific substances. RAST stands for RadioAllergoSorbent
Rat-flea typhus: Murine typhus, an acute infectious disease with
fever, headache, and rash, all quite similar to, but milder
than, epidemic typhus, caused by a related microoganism,
Rickettsia typhi (mooseri), transmitted to humans by rat fleas (Xenopsylla
cheopis). The animal reservoir includes rats, mice and other
rodents. Murine typhus occurs sporadically worldwide but is more
prevalent in congested rat-infested urban areas. Also known as
endemic typhus and urban typhus of Malaya.
Rate, basal metabolic: A measure of the rate of metabolism. For
example, someone with an overly active thyroid will have an
elevated basal metabolic rate.
Rate, birth: The birth rate is usually given as the number of
live births divided by the average population (or the population
at midyear). This is termed the crude birth rate. In 1995, for
example, the crude birth rate per 1,000 population was 14 in the
United States, 16.9 in Australia, etc.
Rate, death: The number of deaths in the population divided by
the average population (or the population at midyear) is the
crude death rate. In 1994, for example, the crude death rate per
1,000 population was 8.8 in the United States, 7.1 in Australia,
etc. A death rate can also be tabulated according to age or
Rate, erythrocyte sedimentation: A sedimentation rate, or "sed
rate", is a blood test that detects and is used to monitor
inflammation activity. It is measured by recording the rate at
which red blood cells (RBCs) sediment in a tube over time. It
increases (the RBCs sediment faster) with more inflammation.
Rate, fetal mortality: The ratio of fetal deaths divided by the
sum of the births (the live births + the fetal deaths) in that
year. In the United States, the fetal mortality rate plummeted
from 19.2 per 1,000 births in 1950 to 9.2 per 1,000 births in
Rate, heart: Number of heart beats per minute. The normal
resting adult heart beats regularly at an average rate of 60
times per minute. (Young children’s hearts beat faster). The
speed of the heartbeat (heart rate) is governed by the speed of
electrical signals from the pacemaker of the heart, the SA node,
located in the right atrium (upper chamber of the heart). The
electrical signals from the SA node travel across the atria and
cause these two upper heart chambers to contract, delivering
blood into the lower heart chambers, the ventricles. The
electrical signals then pass through the AV node to reach the
ventricles. Electrical signals reaching the ventricles cause
these chambers to contract, pumping blood to the rest of the
body, generating the pulse. During rest, the speed of electrical
signals originating from the SA node is slow, so the heart beats
slowly. During exercise or excitement, the speed of signals from
the SA node increases, and the heartbeat quickens.
Rate, infant mortality: The number of children dying under a
year of age divided by the number of live births that year. The
infant mortality rate in the United States, which was 12.5 per
1,000 live births in 1980, fell to 9.2 per 1,000 live births in
Rate, maternal mortality: The number of maternal deaths related
to childbearing divided by the number of live births (or by the
number of live births + fetal deaths) in that year. The maternal
mortality rate in the United States in 1993 (and 1994) was 0.1
per 1,000 live births, or 1 mother dying per 10,000 live births.
Rate, neonatal mortality: The number of children dying under 28
days of age divided by the number of live births that year. The
neonatal mortality rate in the United States, which was 8.4 per
1,000 live births in 1980, declined to 5.8 per 1,000 live births
Rate, pulse: The pulse rate is most often taken at the wrist. It
measures the number of pulsations in the radial artery each
Rate, respiratory: The number of breaths per minute (or, more
formally, the number of movements indicative of inspiration and
expiration per unit time). In practice, the respiratory rate is
usually determined by counting the number of times the chest
rises (or falls) per minute. By whatever means, the aim is to
determine if the respirations are normal, abnormally fast (tachypnea),
abnormally slow (technically termed bradypnea), or nonexistent
Rate, sed: A sedimentation rate, or "sed rate", is a blood test
that detects and is used to monitor inflammation activity. It is
measured by recording the rate at which red blood cells (RBCs)
sediment in a tube over time. It increases (the RBCs sediment
faster) with more inflammation.
Rate, sedimentation: A sedimentation rate, or "sed rate", is a
blood test that detects and is used to monitor inflammation
activity. It is measured by recording the rate at which red
blood cells (RBCs) sediment in a tube over time. It increases
(the RBCs sediment faster) with more inflammation.
Rattlesnake bite: A venomous (poisonous) snake bite. All
rattlesnakes are venomous and secrete poisonous venom.
Raynaud’s phenomenon: A condition resulting in discoloration of
fingers and/or toes when a person is exposed to changes in
temperature (cold or hot) or emotional events. Skin
discoloration occurs because an abnormal spasm of the blood
vessels causes a diminished blood supply. Initially, the digits
involved turn white because of diminished blood supply, then
turn blue because of prolonged lack of oxygen and finally, the
blood vessels reopen, causing a local "flushing" phenomenon,
which turns the digits red. This three-phase color sequence
(white to blue to red), most often upon exposure to cold
temperature, is characteristic of Raynaud’s phenomenon. Named
for the French physician Maurice Raynaud (1834-1881).
Reabsorption: Absorbing again. For example, the kidney
selectively reabsorbs substances such as glucose, proteins, and
sodium which it had already secreted into the renal tubules.
These reabsorbed substances return to the blood.
Reaction, allergic: A reaction that occurs when the immune
system attacks a usually harmless substance (an allergen) that
gains access to the body. The immune system calls upon a
protective substance called immunoglobulin E (IgE) to fight
these invading allergic substances ( allergens). Even though
everyone has some IgE, an allergic person has an unusually large
army of these IgE defenders -in fact, too many for their own
good. This army of IgE antibodies attacks and engages the
invading army of allergic substances of allergens. As is often
the case in war, innocent bystanders are affected by this
battle. These innocent bystanders are special cells called mast
cells. These cells are frequently injured during the warring of
the IgE antibodies and the allergic substances. When a mast cell
is injured, it releases a variety of strong chemicals including
histamine into the tissues and blood that frequently cause
allergic reactions. These chemicals are very irritating and
cause itching, swelling, and fluid leaking from cells. These
allergic chemicals can cause muscle spasm and can lead to lung
and throat tightening as is found in asthma and loss of voice.
Reactive arthritis: Reiter’s syndrome is also called "reactive
arthritis" since it is thought to involve the immune system
which is "reacting" to the presence of bacterial infections in
the genital, urinary, or gastrointestinal systems. Accordingly,
certain people’s immune systems are genetically primed to react
aberrantly when these areas are exposed to certain bacteria. The
aberrant reaction of the immune system leads to inflammation in
the joints and eyes.
Reading frame: One of the three possible ways to read a
nucleotide sequence in DNA (depending upon whether reading
starts with the first, second or third base in a triplet).
Reading frame, open: An open reading frame in DNA has no
termination codon, no signal to stop reading the nucleotide
sequence, and so may be translated into protein.
Reagent: A substance used to produce a chemical reaction to
detect, measure, produce, etc. other substances.
Rebound: Just like a rebound in basketball when the ball
reverses its course and bounces back off the backboard, in
medicine a rebound is a reversal of response upon withdrawal of
Rebound effect: The characteristic of a drug to produce reverse
effects when the effect of the drug has passed or the patient no
longer responds to it.
Recalcitrant: Stubborn. For example, a recalcitrant case of
pneumonia stubbornly resists treatment.
Receptor: In cell biology, a receptor is a structure on the
surface of a cell or inside a cell that selectively receives and
binds a specific substance. There are, for example, insulin
receptors, low-density lipoprotein (LDL) receptors, etc.
However, in neurology, a receptor is the terminal of a sensory
nerve that (receives and) responds to stimuli.
Receptor, visual: The layer of rods and cones, the visual cells,
of the retina.
Recessive: A recessive gene expresses itself only when there is
no other type of gene present at that locus (spot on the genetic
code or chromosome). For example, cystic fibrosis (CF) and
Duchenne muscular dystrophy (DMD) are both recessive disorders.
A CF child has the CF gene on both chromosome 7’s (and so is
said to be homozygous for CF). The DMD boy has the DMD gene on
his sole X chromosome (and so is said to be hemizgous for DMD).
Recessive, autosomal: A gene on a nonsex chromosome (an autosome)
that expresses itself only when there is no different gene
present at that locus (spot on the chromosome). For example,
cystic fibrosis (CF) is an autosomal recessive disorder. A CF
child has the CF gene on both chromosome 7’s (and so is said to
be homozygous for CF).
Recessive, X-linked: A gene on the X chromosome that expresses
itself only when there is no different gene present at that
locus (spot on the chromosome). For example, Duchenne muscular
dystrophy (DMD) is an X-linked recessive disorder. A DMD boy has
the DMD gene on his sole X chromosome (and so is said to be
hemizgous for DMD). Although it is much rarer, a girl can have
DMD (by several different means as, for example, if she has the
DMD gene on both her X chromosomes and so is homozygous for DMD).
Recipient: In medicine, a recipient is someone who receives
something like a blood transfusion or an organ transplant. The
recipient is beholden to the donor.
Reciprocal treanslocation: Mutual exchange of chromosome
segments between two nonhomologous chromosomes (chromosomes that
do not belong to the same pair).
Recombinant: A person with a new combination of genes, a
combination of genes not present in either parent, due to
parental recombination of those genes.
Recombinant clones: Clones containing recombinant DNA molecules.
Recombinant DNA molecules: A combination of DNA molecules of
different origin that are joined using recombinant DNA
Recombinant DNA technology: A series of procedures used to join
together (recombine) DNA segments. A recombinant DNA molecule is
constructed (recombined) from segments from 2 or more different
DNA molecules. Under certain conditions, a recombinant DNA
molecule can enter a cell and replicate there, autonomously (on
its own) or after it has become integrated into a chromosome.
Recombination: The trading of fragments of genetic material
between chromosomes before the egg and sperm cells are created.
Key features of recombination include the point-to-point
association of paired chromosomes (synapsis) followed by the
visible exchange of segments (crossing over) at X-shaped
crosspoints (chiasmata). Recombination is the principal way of
creating genetic diversity between generations. By shuffling the
genetic deck of cards, recombination ensures that children are
dealt a different genetic hand than their parents.
RECOMBIVAX-HB: A vaccine against hepatitis B (hep B) to
stimulate the body’s immune system to produce antibodies against
the hep B virus.
Recrudescence: Reappearance. In Latin, recrudescere meant to
become raw or sore again. Recrudescence has broadened out so
there can now be the recrudescence of a rash, of arthritis, etc.
Rectal: Having to do with the rectum.
Rectal cancer: A malignant tumor arising from the inner wall of
the large intestine. The third leading cause of cancer in males,
fourth in females in the U.S. Risk factors include heredity
(family history), colon polyps, and long-standing ulcerative
colitis. Most colorectal cancers develop from polyps. Colon
polyp removal can prevent colorectal cancer. Colon polyps and
early cancer can have no symptoms so regular screening is
important. Diagnosis of colorectal cancer can be made by barium
enema or by colonoscopy with biopsy confirmation of cancer.
Rectum: The last 6 to 8 inches of the large intestine. The
rectum stores solid waste until it leaves the body through the
anus. The word rectum comes from the Latin rectus meaning
straight (which the human rectum is not).
Recuperate: To recover health and strength. From the Latin
recuperare meaning to regain, get back, recover. To recuperate
is to convalesce.
Recur: To occur again. To return. Any symptom (such as fatigue),
any sign (such as a heart murmur), or any disease can recur.
Recurrence: The return of a sign, symptom or disease after a
remission. The reappearance of cancer cells at the same site or
in another location is, unfortunately, a familiar form of
Recurrence risk: In medical genetics, the recurrence risk is the
chance that a genetic (inherited) disease present in the family
will recur in that family and affect another person (or
persons). It is the chance of "lightning striking twice" (or
Recurrent: Back again. A recurrent fever is a fever that has
returned after an intermission: a recrudescent fever.
Recurrent laryngeal nerve: A branch of a nerve (the vagus nerve)
that comes down the neck and turns back ("recurs") to supply the
larynx (the "voice box").
Red blood cells: Red blood cells (RBCs) are cells that carry
oxygen in the blood. They are also called red corpuscles.
Red cells: Short for red blood cells, the oxygen/carbon dioxide
carrying cells in blood. Also known acronymically as RBC’s, red
corpuscles or erythrocytes (literally, red hollow vessels).
Red corpuscles: Red corpuscles are cells that carry oxygen in
the blood. They are also called red blood cells or "RBCs."
Reduction division: The first cell division in meiosis, the
process by which germ cells are formed. A unique event in which
the chromosome number is reduced from diploid (46 chromosomes)
to haploid (23 chromosomes). Also called first meiotic division
or first meiosis.
Reed-Sternberg cell: A type of cell that appears in patients
with Hodgkin's disease. The number of these cells increases as
the disease advances.
Referral: The recommedation of a medical or paramedical
professional. If you get a referral, for example, to
ophthalmology, you are sent to the eye doctor. The earliest
recorded use of the word referral in medicine was in 1927.
Reflex: A reaction that is involuntary. The corneal reflex is
the blink that occurs with irritation of the eye. The nasal
reflex is a sneeze.
Reflex sympathetic dystrophy syndrome (RSDS): A condition that
features a group of typical symptoms, including pain (often
"burning" type), tenderness, and swelling of an extremity
associated with varying degrees of sweating, warmth and/or
coolness, flushing, discoloration, and shiny skin.
Reflux: The term used when liquid backs up into the esophagus
from the stomach.
Reflux disease, gastroesophageal (GERD): The stomach contents
regurgitate and back up (reflux) into the esophagus The food in
the stomach is partially digested by stomach acid and enzymes.
Normally, the partially digested acid content in the stomach is
delivered by the stomach muscle down into the small intestine
for further digestion. With esophageal reflux, stomach acid
content refluxes back up into the esophagus, occasionally
reaching the breathing passages, causing inflammation and damage
to the esophagus, as well as to the lung and larynx (the voice
box). 10% of patients with GERD develop Barrett’s esophagus, a
risk fractor in cancer of the esophagus.
Reflux, esophageal: A condition wherein stomach contents
regurgitate or back up (reflux) into the esophagus (a long
cylindrical tube that transports food from the mouth to the
stomach). The food in the stomach is partially digested by
stomach acid and enzymes. Normally, the partially digested acid
content in the stomach is delivered by the stomach muscle into
the small intestine for further digestion. In esophageal reflux,
stomach acid content refluxes backwards up into the esophagus,
occasionally reaching the breathing passages, causing
inflammation and damage to the esophagus, as well as to the lung
and larynx (the voice box). The overall process is medically
termed gastroesophageal reflux disease (GERD). 10% of patients
with GERD develop a Barrett’s esophagus which can increase the
risk of cancer of the esophagus.
Reflux laryngitis: Inflammation of the voice box (larynx) caused
by stomach acid backing up into the esophagus. Reflux laryngitis
can cause chronic hoarseness and be associated with other
symptoms of inflammation of the esophagus, such as heartburn.
Many treatment options are available.
Refraction: Checking the eyes for refractive errors
(nearsighted, farsighted, astigmatism) and correcting those
Refractory: Not yielding (at least not yielding readily) to
Refractory anemia: Anemia (a shortage of red blood cells)
unresponsive to treatment.
Refsum’s disease: A genetic disorder of the fatty acid phytanic
acid which accumulates and causes a number of progressive
problems including polyneuritis (inflammation of numerous
nerves), diminishing vision (due to retinitis pigmentosa), and
wobbliness (ataxia) caused by damage to the cerebellar portion
of the brain (cerebellar ataxia).
Regenerate: To reproduce or renew something lost. For example,
after an injury, the liver has the capacity to regenerate.
Regimen: With the accent on the first syllable (reg as in Reggie
Jackson), a regimen is a plan, a regulated course such as a
diet, exercise or treatment, designed to give a good result. A
low-salt diet is a regimen.
Region, regulatory: See: Regulatory sequence.
Regional eneteritis: Crohn’s disease, a chronic inflammatory
disease of the intestine primarily in the small and large
intestines but which can occur anywhere in the digestive system
between the mouth and the anus. Named after Burrill Crohn who
described the disease in 1932. The disease usually affects
persons in their teens or early twenties. It tends to be
chronic, recurrent with periods of remission and exacerbation.
In the early stages, it causes small scattered shallow
crater-like areas (erosions) called apthous ulcers in the inner
surface of the bowel. With time, deeper and larger ulcers
develop, causing scarring and stiffness of the bowel and the
bowel becomes increasingly narrowed, leading to obstruction.
Deep ulcers can puncture holes in the bowel wall, leading to
infection in the abdominal cavity (peritonitis) and in adjacent
organs.When only the large intestine (colon) is involved, the
condition is called Crohn’s colitis. When only the small
intestine is involved, the condition is called Crohn’s
enteritis. When only the end of the small intestine (the
terminal ileum) is involved, it is termed terminal ileitis. When
both the small intestine and the large intestine are involved,
the condition is called Crohn’s enterocolitis (or ileocolitis).
Abdominal pain, diarrhea, vomiting, fever, and weight loss can
be symptoms. Crohn’s disease can be associated with reddish
tender skin nodules, and inflammation of the joints, spine,
eyes, and liver. Diagnosis is by barium enema, barium x-ray of
the small bowel, and colonoscopy. Treatment includes medications
for inflammation, immune suppression, antibiotics, or surgery.
(The disease is also called granulomatous enteritis).
Registry: Although a registry was originally the place (like
Registry House in Edinburgh) where information was collected (in
registers), the word registry has also come to mean the
collection itself. A registry is usually organized so the data
can be analyzed. For example, analysis of data in a tumor
registry maintained at a hospital may show a rise in lung cancer
Regress: To return or go back. For example, if a 5-year-old
child begins to regress (and function like a much younger
child), that is worrisome.
Regulatory gene: A gene that regulates the expression of other
genes. A regulatory gene is a nosy gene whose prime
preoccupation is to horn in on other genes and control the rate
at which they make products.
Regulatory region: See: Regulatory sequence.
Regulatory sequence: A sequence of bases in DNA that controls
Regurgitation: A backward flowing. For example, of food. Or the
sloshing of blood back into the heart (or between chambers of
the heart) when a heart valve is incompetant and does not close
Rehab: Short for Rehabilitation.
Rehabilitation: The restoration of skills by a person who has
suffered an illness or injury so they regain maximum
self-sufficiency. After a stroke, rehabilitation may be
important to walk again and speak clearly again.
Rehydrate: To restore water. If a child has severe diarrhea,
loses a lot of water in the stools and so becomes seriously
dehydrated, it is imperative to rehydrate that child properly
Reiter’s syndrome: A chronic form of inflammatory arthritis
wherein the following three conditions are combined: (1)
arthritis; (2) inflammation of the eyes (conjunctivitis); and
(3) inflammation of the genital, urinary or gastrointestinal
Rejection: In transplantation biology, the refusal by the body
to accept transplanted cells, tissues or organs. For example, a
kidney transplanted may be rejected.
Relapse: The return of signs and symptoms of a disease after a
Relaxant: Something that relaxes, relieves, reduces tension. For
example, a muscle relaxant is often administered during
abdominal surgery to relax the diaphragm and keep it from moving
during the surgery.
rem: In radiation, Roentgen equivalent for man, a roentgen (an
international unit of X- or gamma-radiation) adjusted for the
atomic makeup of the human body. In ophthalomology, rapid eye
Remedy: Something that consistently helps treat or cures a
disease. From the Latin remedium meaning that which heals again
Remission: Disappearance of the signs and symptoms of cancer or
other disease. When this happens, the disease is said to be "in
remission." A remission can be temporary or permanent.
Remission induction chemotherapy: The initial chemotherapy a
patient with acute leukemia receives to bring about a remission.
Renal: Having to do with the kidney. From the Latin renes (the
kidneys), which gave the French les reins which mean both the
kidneys and the lower back.
Renal cancer: Childhood kidney cancer is different from adult
kidney cancer. The most common symptom of kidney cancer is blood
in the urine. The diagnosis of kidney cancer is supported by
findings of the medical history and examination, blood, urine,
and x-ray tests, and confirmed by a biopsy.
Renal capsule: The fibrous connective tissue that surrounds each
Renal cell cancer: Cancer that develops in the lining of the
renal tubules, which filter the blood and produce urine. Also
called renal cell carcinoma.
Renal cell carcinoma: Cancer that develops in the lining of the
renal tubules, which filter the blood and produce the urine.
Also called renal cell cancer.
Renal osteodystrophy: A combination of bone disorders usually
caused by chronic kidney failure (renal disease). Can also occur
because of abnormal kidney functioning at birth (congenital).
When the kidneys have failed, death is imminent unless dialysis
is given. Therefore, patients with osteodystrophy are usually on
dialysis therapy. This bone disease, which is also simply called
osteodystrophy, is common in patients on chronic hemodialysis.
Renal pelvis: The area at the center of the kidney. Urine
collects here and is funneled into the ureter.
Renal tubules: Small structures in the kidney that filter the
blood and produce the urine.
rep: Stands for roentgen equivalent physical. A rep is a unit of
absorbed radiation approximately equivalent to a roentgen, an
international unit of X- or gamma-radiation.
Repair, DNA: The cell has a series of special enzymes to repair
mutations (changes) in the DNA and restore the DNA to its
Reperfusion: The restoration of blood flow to an organ or
tissue. After a heart attack, an immediate goal is to quickly
open blocked arteries and reperfuse the heart muscles. Early
reperfusion minimizes the extent of heart muscle damage and
preserves the pumping function of the heart.
Repetitive DNA: DNA sequences that are repeated in the genome.
Replication: A turning back, repetition, duplication,
Replication, DNA: A wondrous complex process whereby the
("parent") strands of DNA in the double helix are separated and
each one is copied to produce a new ("daughter") strand. This
process is said to be "semi-conservative" since one of each
parent strand is conserrved and remains intact after replication
has taken place.
Reporting, anonymous: In public health, anonymous reporting
permits the acquisition of certain data such as the proportion
of persons with a positive test or with a disease. It is
different from anonymous testing, in which no name is used on
the test sample.
Reporting, named: In public health, named reporting is the
reporting of infected persons by name to public health
departments. This is standard practice for the surveillance of
many infectious diseases such as syphilis, gonorrhea, and
tuberculosis that pose a public health threat. The opposite of
named reporting is anonymous testing in which the individual
Reporting, unique identifier: In public health, a system that
uses information such as the person’s birth date and part of
their identification number (in the U.S., the social security
number) to create a unique code that is reported instead of a
name. It is an alternative to named reporting that provides some
of the surveillance benefits of reporting by name, such as the
elimination of duplicate reports, while reducing privacy
concerns by avoiding use of a person’s name. This system is used
with HIV testing for example in Maryland and Texas.
Reproduction: The production of offspring. Reproduction need not
be sexual. Yeast can reproduce by budding.
Reproductive cells: The eggs and sperm are the reproductive
cells. Each mature reproductive cell is haploid in that it has a
single set of 23 chromosomes.
Reproductive system: In women, the organs that are directly
involved in producing eggs and in conceiving and carrying
Resection: Surgical removal of part of an organ.
Reservoir, Ommaya: A device implanted under the scalp and used
to deliver anticancer drugs to the fluid surrounding the brain
and spinal cord.
Residual: Something left behind. With residual disease, the
disease has not been eradicated.
Resistance, antibiotic: The ability of bacteria and other
microorganisms to withstand an antibiotic to which they were
once sensitive (and were once stalled or killed outright). Also
called drug resistance.
Resistance, pulmonary: The opposition of the respiratory tree to
Resistance, vascular: The opposition to the flow of blood across
a vascular bed.
Resolution: In genetics, resolution refers to the degree of
molecular detail on a physical map of DNA, ranging from low to
Resorb: Literally, to absorb again. To lose substance. Some of a
tooth may be resorbed.
Resorption: The process of losing substance. Bone when it is
remodeled (reshaped) undergoes both new formation and resorption.
Respiration: Respiration is the act of inhaling and exhaling air
in order to exchange oxygen for carbon dioxide.
Respiratory: Having to do with respiration. The word comes from
the Latin re- (again) + spirare (to breathe) = to breathe again.
Respiratory rate: The number of breaths per minute (or, more
formally, the number of movements indicative of inspiration and
expiration per unit time). In practice, the respiratory rate is
usually determined by counting the number of times the chest
rises (or falls) per minute. By whatever means, the aim is to
determine if the respirations are normal, abnormally fast (tachypnea),
abnormally slow (technically termed bradypnea), or nonexistent
Respiratory system: The organs that are involved in breathing.
These include the nose, throat, larynx, trachea, bronchi, and
Respiratory therapy: Exercises and treatments that help patients
recover lung function, such as after surgery.
Resting phase: More appropriately called interphase. The
interval in the cell cycle between two cell divisions when the
individual chromosomes cannot be distinguished, interphase was
once thought to be the resting phase but it is far from a time
of rest for the cell. It is the time when DNA is replicated in
the cell nucleus.
Restitution: In cytogenetics, the spontaneous rejoining of
broken chromosomes to reconstitute the original chromosome
Restriction endonuclease: An enzyme from bacteria that can
recognize specific base sequences in DNA and cut (restrict) the
DNA at that site (the restriction site). Also called a
Restriction enzyme: An enzyme from bacteria that can recognize
specific base sequences in DNA and cut (restrict) the DNA at
that site (the restriction site). Also called a restriction
Restriction fragment length polymorphism (RFLP): A difference in
DNA between people that can be recognized by the use of a
Restriction map: An array of sites in DNA susceptible to
cleavage by diverse restriction enzymes.
Restriction site: A sequence in DNA that can be recognized and
cut by a specific restriction enzyme.
Retinoblastoma: A malignant eye tumor caused by the loss of a
pair of tumor-suppressor genes. An inherited form of
retinoblastoma (it typically appears at birth, leads to multiple
tumors and affects both eyes) is due to a transmissible (germline)
mutation followed by an acquired (somatic) mutation. The
sporadic form of retinoblastoma (it has later onset and leads to
a single tumor in one eye) is due to acquired (somatic)
mutations of both tumor-suppressor genes. When the tumor is
detected at an early stage, it can sometimes be treated locally,
but it oftren unfortunately requires removal of the eye (enucleation).
Retropubic prostatectomy: Surgical removal of the prostate
through an incision in the abdomen.
Retrosternal: Behind the sternum (the breastbone).
Retrovirus: An RNA virus (a virus composed not of DNA but of
RNA). Retroviruses have an enzyme called reverse transcriptase
that gives them the unique property of transcribing RNA (their
RNA) into DNA. The retroviral DNA can then integrate into the
chromosomal DNA of the host cell to be expressed there.
Reversal of organs, total: This condition (medically called
situs inversus totalis) involves complete transposition (right
to left reversal) of the thoracic and abdominal organs. The
heart is not in its usual position in the left chest but is on
the right. Specifically related to the heart, this is referred
to as dextrocardia (literally, right-hearted). And the stomach,
which is normally in the left upper abdomen, is on the right. In
patients with situs inversus totalis, all of the chest and
abdominal organs are reversed and appear in mirror image when
examined or visualized by tests such as x-ray filming. Situs
inversus totalis has been estimated to occur once in about
6-8,000 births. Situs inversus occurs in a rare abnormal
condition that is present at birth (congenital) called
Reverse genetics: In classic genetics, the traditional approach
was to find a gene product and then try to identify the gene
itself. In molecular genetics, the reverse has been done by
identifying genes purely on the basis of their position in the
genome with no knowledge whatsoever of the gene product. This
revolutionary approach is reverse genetics. Also called
Reverse transcriptase: An enzyme that permits DNA to be made
using RNA as the template. A retrovirus (a virus composed of
RNA) can propagate by converting its RNA into DNA with the
invaluable assistance of reverse transcriptase.
Reye’s syndrome: A sudden, sometimes fatal, disease of the brain
(encephalopathy) with degeneration of the liver, occurs in
children (most cases 4-12 years of age), comes after the
chickenpox (varicella) or an influenza-type illness, is also
associated with taking medications containing aspirin. The child
with Reye’s syndrome first tends to be unusually quiet,
lethargic (stuporous), sleepy, and vomiting. In the second
stage, the lethargy deepens, the child is confused, combative
and delirious. And things get worse from there with decreasing
consciousness, coma, seizures, and eventually death. The
prognosis (outlook) depends on early diagnosis and control of
the increased intracranial pressure. Reye’s syndrome is a good
reason to have your child immunized against chickenpox and not
give the child aspirin for fever.
RF: Rheumatoid factor.
RFLP (Restriction Fragment Length Polymorphism ): A difference
in DNA between people that can be recognized by the use of a
Rh: A blood group system and one of the most complex. A person
can be said to be Rh-positive or Rh-negative. Rh stands for
Rhabdomyolysis: A condition whereby skeletal muscle is broken
down, releasing intracellular (inside the cell) muscle enzymes
and electrolytes. The major risks of this condition are two
fold: one is obviously muscle breakdown and the other is kidney
failure. The myoglobin, an intracellular component, is toxic to
the kidneys and may lead to kidney failure. Rhabdomyolysis is
relatively uncommon, but most often occurs as the result of
extensive muscle damage, for example crush injury or electrical
shock. Other causes many be drug or toxin, for example many of
the cholesterol lowering medications have the potential to cause
this disorder. Underlying diseases can also lead to
rhabdomyolysis, including collagen vascular diseases (such as
systemic lupus erythematosus) and others, which if left
untreated may also cause this muscle degradation.
Rheumatism: Rheumatism is an older term, used to describe any of
a number of painful conditions of muscles, tendons, joints, and
Rheumatoid arthritis: An autoimmune disease which causes chronic
inflammation of the joints, the tissue around the joints, as
well as other organs in the body. Autoimmune diseases occur when
the body tissues are mistakenly attacked by its own immune
system. The immune system is a complex organization of cells and
antibodies designed normally to "seek and destroy" invaders of
the body, particularly infections. Patients with these diseases
have antibodies in their blood which target their own body
tissues, where they can be associated with inflammation. Because
it can affect multiple other organs of the body, rheumatoid
arthritis is referred to as a systemic illness and is sometimes
called rheumatoid disease. While rheumatoid arthritis is a
chronic illness (meaning it can last for years) patients may
experience long periods without symptoms.
Rheumatoid arthritis, systemic-onset juvenile (Still’s disease):
Also known as systemic-onset juvenile chronic arthritis. Still’s
disease presents with systemic (bodywide) illness including high
intermittent fever, a salmon-colored skin rash, swollen lymph
glands, enlargement of the liver and spleen, and inflammation of
the lungs (pleuritis) and around the heart (pericarditis). The
arthritis may not be immediately apparent but it does appear and
may persist after the systemic symptoms are gone.
Rheumatoid factor: Rheumatoid factor is an antibody that is
measurable in the blood. It is commonly used as a blood test for
the diagnosis of rheumatoid arthritis. Rheumatoid factor is
present in about 80% of adults (but a much lower proportion of
children) with rheumatoid arthritis. It is also present in
patients with other connective tissue diseases (such as systemic
lupus erythematosus) and in some with infectious diseases (such
as infectious hepatitis).
Rheumatoid nodules: Rheumatoid nodules are firm lumps in the
skin of patients with rheumatoid arthritis that usually occur in
pressure points of the body, most commonly the elbows
Rheumatology: A subspecialty of internal medicine that involves
the non-surgical evaluation and treatment of the rheumatic
diseases and conditions. Rheumatic diseases and conditions are
characterized by symptoms involving the musculoskeletal system.
Many of the rheumatic diseases and conditions feature immune
system abnormalities. Therefore, rheumatology also involves the
study of the immune system. Classical rheumatology training
includes 4 years of medical school, 1 year of internship in
internal medicine, 2 years of internal medicine residency, and 2
years of rheumatology fellowship. There is a subspecialty board
for rheumatology certification. The American College of
Rheumatology is the official organization acting on behalf of
the field of rheumatology in the United States.
Rhinitis: Irritation of the nose. Derived from the Greek word
rhinos meaning of the nose.
Rhinitis, allergic: The medical term for hayfever. (Hay fever"is
a misnomer since hay is not a usual cause of this problem and
there is no fever. Many substances cause the allergic symptoms
in hay fever. Allergic rhinitis is the correct term for this
allergic reaction. Rhinitis means "irritation of the nose" and
is a derivative of Rhino, meaning nose.) Symptoms include nasal
congestion, a clear runny nose, sneezing, nose and eye itching,
and tearing eyes. Post-nasal dripping of clear mucus frequently
causes a cough. Loss of smell is common and loss of taste occurs
occasionally. Nose bleeding may occur if the condition is
severe. Eye itching, redness, and tearing frequently accompany
the nasal symptoms.
Rhinitis, allergic, perennial: Allergic rhinitis (hayfever) that
occurs throughout the year.
Rhinitis, allergic, seasonal: Allergic rhinitis (hayfever) which
occurs during a specific season.
Rhinoplasty: Plastic surgery on the nose, known familiarly as a
Rhinorrhea: Medical term for a runny nose. From the Greek words
"rhinos" meaning "of the nose" and "rhoia" meaning "a flowing."
Rib: Any one of the twelve paired bones which form the skeletal
structure of the chest wall (rib cage). The ribs attach to the
building blocks of the spine (vertebrae) in the back. The first
seven ribs attach to the sternum in the front and are known as
true ribs. The lower five ribs do not directly connect to the
sternum and are known as false ribs.
RiboNucleic Acid (RNA): A chemical similar to DNA, The several
classes of RNA molecules play important roles in protein
synthesis and other cell activities.
Ribosomes: Structures (called organelles) composed of RNA and
protein situated outside the nucleus in the cytoplasm of the
cell where the cell uses messenger RNA to make up polypeptides.
Rickettsia: A member of a group of microorganisms that (like
viruses) require other living cells for growth but (like
bacteria) use oxygen, have metabolic enzymes and cell walls, and
are susceptible to antibiotics. Rickettsiae cause a series of
diseases (See Rickettsial diseases).
Rickettsial diseases: The infectious diseases caused by the
rickettsiae fall into 4 groups:(1) typhus: epidemic typhus,
Brill-Zinsser disease, murine (endemic) typhus, and scrub
typhus; (2) spotted fever—Rocky Mountain spotted fever, Eastern
tick-borne rickettsioses, and rickettsialpox; (3) Q fever; and
(4) trench fever.
Rickettsialpox: A mild infectious disease first observed in New
York City caused by Rickettsia akari, transmitted from its mouse
host by chigger or adult mite bites. There is fever, a dark spot
that becomes a small ulcer at the site of the bite, swollen
glands (lymphadenopathy) in that region, and a raised blistery
(vesicular) rash. Also known as vesicular rickettsiosis.
Rickettsioses: The infectious diseases caused by the rickettsiae.
See Rickettsial diseases.
Rickettsioses of the eastern hemisphere, tick-borne: Thare are 3
known diseases caused by infection with rickettsial agents> They
are North Asian tick-borne rickettsiosis, Queensland tick
typhus, and African tick typhus (fièvre boutonneuse).
Rickettiosis, North Asian tick-borne: One of the tick-borne
rickettsial diseases of the eastern hemisphere, similar to Rocky
Mountain spotted fever, but less severe, with fever, a small
ulcer (eschar) at the site of the tick bite, swollen glands
nearby (satellite lymphadenopathy), and a red raised (maculopapular)
Rickettsiosis, vesicular: See Rickettsialpox.
Ring chromosome: A structurally abnormal chromosome in which the
end of each chromosome arm has been lost and the broken arms
have been reunited in ring formation. A ring chromosome is
denoted by the symbol r.
Ringworm of the nails: The most common fungus infection of the
nails (onychomycosis). Onychomycosis makes the nails look white
and opaque, thickened, and brittle. Older women (perhaps because
estrogen deficiency may increase the risk of infection). and men
and women with diabetes or disease of the small blood vessels
(peripheral vacscular disease) are at increased risk. Artificial
nails (acrylic or "wraps") increase the risk because when an
artificial nail is applied, the nail surface is usually abraded
with an emery board damaging it, emery boards can carry
infection, and. water can collect under the nail creating a
moist, warm environment for fungal growth. Alternative names
include tinea unguium and dermatophytic onychomycosis.
Risk factor: Something that increases a person's chances of
developing a disease.
Risk of recurrence: In medical genetics, the chance that a
genetic (inherited) disease present in a family will recur in
that family. The concept in general medicine means the chance
that an illness we come back again.
Ritter disease: This is the scalded skin syndrome, a potentially
serious side effect of infection with the Staph (Staphylococcus)
bacteria that produces a specific protein which loosens the
"cement" holding the various layers of the skin together. This
allows blister formation and sloughing of the top layer of skin.
If it occurs over large body regions it can be deadly (just like
a large surface area of the body having been burned). It is
necessary to treat scalded skin syndrome with intravenous
antibiotics and to protect the skin from allowing dehydration to
occur if large areas peel off. The disease occurs predominantly
in children under 5 years of age. It is known formally as
Staphyloccoccal scalded skin syndrome.
RMSF: Rocky Mountain spotted fever.
RNA: Short for ribonucleic acid. A chemical (specifically, a
nucleic acid) similar to DNA but containing ribose rather than
deoxyribose. RNA is in fact formed upon a DNA template. The
several classes of RNA molecules play crucial roles in protein
synthesis and other cell activities. (See also messenger RNA,
transfer RNA and ribosomal RNA.)
RNA, messenger: A class of RNA that is the template upon which
polypeptides are put together. Abbreviated mRNA.
RNA polymerase: Enzyme that catalyzes (speeds) the
polymerization of RNA. RNA polymerase uses preexisting nucleic
acid templates and assembles the RNA from ribonucleotides.
RNA, ribosomal: A component of ribosomes, ribosomal RNA
functions as a nonspecific site for making polypeptides.
Ribosomal RNA is abbreviated rRNA.
RNA, transfer: In cooperation with the ribosomes, transfer RNA
brings (transfers) activated amino acids into position along the
messenger RNA template. The abbreviation for transfer RNA is
RNA polymerase: A polymerase is an enzyme that catalyzes the
joining of many smaller molecules (called monomers) to form a
big molecule (a macromolecule). RNA polymerase is a unique
enzyme that makes (synthesizes) thye macromolecule RNA using DNA
as the template.
Robertsonian translocation: A type of chromosome rearrangement
involving all of the essential genetic material of the long arms
of two acrocentric chromosomes. The acrocentric chromosomes
(those with the centromere near the end so there is only a tiny
short arm) are chromosomes 13-15, 21 and 22 in humans. Named
after W.R.B. Robertson who in 1916 first described this kind of
chromosome rearrangement (in grasshoppers), Robertsonian
translocations are also known as whole-arm or centric-fusion
translocations. They are relatively common in humans and
contribute to the toll of trisomy 13 syndrome and Down syndrome.
Rocky Mountain spotted fever (RMSF): An acute febrile (feverish)
disease initially recognized in the Rocky Mountain states,
caused by Rickettsia rickettsii transmitted by hard-shelled (ixodid)
ticks. Occurs only in the Western Hemisphere. Anyone frequenting
tick-infested areas is at risk for RMSF. Onset of symptoms is
abrupt with headache, high fever, chills, muscle pain. and then
a rash .The rickettsiae grow within damaged cells lining blood
vessels which may become blocked by clots. Blood vessel
inflammation (vasculitis) is widespread Early recognition of
RMSF and prompt antibiotic treatment is important in reducing
mortality. Also called spotted fever, tick fever, and tick
Roentgen: Named for Wilhelm Conrad Roentgen who discovered
X-rays, a roentgen (abbreviated R). An international unit of X-
Roentgenology: Radiology is also known as roentgenology after
Wilhelm Conrad Roentgen who discovered X-rays in 1895. Both
terms refer to the science of radiation, both ionizing (like
X-ray) and nonionizing (like ultrasound), applied to the
diagnosis and treatment of disease.
Rooting reflex: When the cheek or lip is touched, a newborn baby
automatically roots and turns the face toward the stimulus. The
rooting reflex helps with breast-feeding.
Roseola: Short for Roseola infantum, a viral disease of infants
and young children with sudden onset of high fever which lasts
several days and then suddenly subsides leaving in its wake a
fine red rash. The causative agent is herpesvirus type 6 so the
disease is known as Sixth Disease. Also as Exanthem subitum
(sudden rash), pseudorubella, roseola infantilis.
Roseola infantilis: Another name for Roseola.
Roseola infantum: The full name for Roseola.
Rotavirus: A leading cause of severe diarrhea in early childhood
(acute infantile gastroenteritis), rotavirus infection each year
causes an estimated 500,000 doctor visits and 50,000 hospital
admissions in the United States. Almost everyone catches
rotavirus in childhood but, with good nutrition and rehydration,
nearly all recover uneventfully. However, in poor countries
there are at least 600,000 deaths of children under 5 years from
rotavirus diarrhea and dehydration. Rotavirus was discovered in
1973 and took its name from its wheel-like appearance (rota
means wheel in Latin). A vaccine has been reported in The New
England Journal of Medicine (vol. 337, pp. 1181-7, 1997) to
provide a high level of protection against severe diarrhea
caused by rotavirus.
Rothmund-Thomson syndrome (RTS): A genetic disorder with
numerous features affecting skin (premature aging, excess
pigmentation, dilated blood vessels),eyes (juvenile cataract),
nose (saddle nose), teeth (maldeveloped), skeletal system
(congenital bone defects) hair (abnormal), gonads
(underdevelopment) limbs (soft tissue contractures), growth
(short stature), blood (anemia) and a tendency to develop a type
of bone cancer (osteogenic sarcoma). The RTS gene is on
chromosome 8. The syndrome is recessive so to be affected with
RTS a child has to have two RTS genes, one from each parent. RTS
is also called "poikiloderma atrophicans and cataract".
Rubella immunization: The standard MMR vaccine is given to
prevent measles, mumps and rubella (German measles). The MMR
vaccine is now given in two dosages. The first should be given
at12-15 months of age. The second vaccination should be given at
4-6 years (or, alternatively, 11-12 years) of age. Most colleges
require proof of a second measles or MMR vaccination prior to
entrance. Most children should receive MMR vaccinations.
Exceptions may include children born with an inability to fight
off infection, some children with cancer, on treatment with
radiation or drugs for cancer, on long term steroids
(cortisone). People with severe allergic reactions to eggs or
the drug neomycin should probably avoid the MMR vaccine.
Pregnant women should wait until after delivery before being
immunized with MMR. People with HIV or AIDS should normally
receive MMR vaccine. Measles, mumps, and rubella vaccines may be
administered as individual shots, if necessary, or as a
Runny nose: Rhinorrhea is the medical term for this common
problem. From the Greek words "rhinos" meaning "of the nose" and
"rhoia" meaning "a flowing."
Ruptured spleen: Rupture of the capsule of the spleen, an organ
in the upper left part of the abdomen, is a potential
catastrophe that requires immediate medical and surgical
attention. Splenic rupture permits large amounts of blood to
leak into the abdominal cavity which is severely painful.and
life-threatening. Shock and, ultimately, death can result.
Patients typically require an urgent operation. Rupture of a
normal spleen can be caused by trauma, for example, in an
accident. If an individual’s spleen is enlarged, as is frequent
in mononucleosis, most physicians will not allow activities
(such as major contact sports) where injury to the abdomen could