q arm of a
chromosome: The long arm of a chromosome. All human
chromosomes have 2 arms: the short (p) arm and the long (q)
in population genetics: The frequency of the less common of two
different alternative (allelic) versions of a gene. (The
frequency of the more common allele is p).
bands: The alternating bright and dull fluorescent bands seen on
chromosomes under ultraviolet light after the chromosomes are
stained with quinacrine. The Q stands for Quinacrine, an agent
used as an antimalarial agent and, in the laboratory, as a
q.d.: Seen on a prescription, q.d. (or qd) means one a day (from
the Latin quaque die).
Q-fever: An acute (abrupt-onset), self-limited febrile illness
first reported in 1935 in Queensland, Australia. The Q is said
not to be for Queensland, but for Query since the cause of the
disease was long a query (question mark). It is now known to be
due to Coxiella burnetti, a rickettsia (a peculiar group of
bacteria). Aside from sudden onset of fever, there is headache,
malaise, and pneumonia (interstitial pneumonitis) but no rash.
q.i.d.: Seen on a prescription, q.i.d. (or qid) means 4 times a
day (from the Latin quater in die).
q.h.: Abbreviation for "every hour." On a prescription or
doctor's hospital orders, q.h. means every hour. Also written qh
(without the periods). From the Latin quaque die.
q.n.s.: On a lab report, q.n.s. (or qns or QNS) means Quantity
Not Sufficient. Not enough blood, urine or whatever to do the
QRS complex: The deflections in an electrocardiographic (ECG or
EKG) tracing that represent the ventricular activity of the
Quackery: Deliberate misrepresentation of the ability of a
substance or device for the prevention or treatment of disease.
We may think that the day of patent medicines is gone but look
around you and you will see them still. They appeal to our
desire to believe that every disease is curable or at least
treatable. Quackery also applies to persons who pretend to be
able to diagnose or heal people but are unqualified and
Quadrant: A quarter. For example, the liver is in the right
upper quadrant of the abdomen.
Quadriceps: Any four-headed muscle but usually refers to the
quadriceps muscle of the thigh, the large muscle that comes down
the femur (the bone of the upper leg), over the patella (the
kneecap) and anchors into the top of the tibia (the big bone in
the lower leg). The function of the quadriceps is to straighten
out (extend) the leg. For those who are into Latin, this
muscle's name is musculus quadriceps femoris. For those who
prefer nicknames, it is the quad.
Quadriparesis: Weakness of all four limbs, both arms and both
legs, as for example from muscular dystrophy.
Quadriplegia: Paralysis of all four limbs, both arms and both
legs, as from a high spinal cord accident or stroke.
Qualitative: Having to do with quality. In contrast to
quantitative (which pertains to quantity, the amount).
Quantitative: Having to do with quantity or with the amount.
Quarantine: The period of isolation decreed to control the
spread of infectious disease. Before the era of antibiotics and
the like, quarantine as one of the few available means for
halting the reach of infectious diseases. The word quarantine
comes from the Latin quadraginta meaning forty. This was
probably because it was known that the incubation period of most
infectious diseases was less than 40 days.
Quasi-: Prefix meaning seemingly.
Quasidiploid: Seems to have the usual two full sets of 23
chromosomes and so to have a normal chromosome complement, but
on closer examination, this is not so. Many malignant cells are
quasidiploid. Also called pseudodiploid.
Quasidominant: Pattern of inheritance that seems due to a
dominant trait but, in fact, is due to the mating of a person
who has a recessive disorder (with 2 copies of a gene causing
the disease) with someone who is an asymtomatic carrier ( and
has 1 copy of the same gene buut no symptoms).
Queensland tick typhus: 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) rash.
Quickening: This apt word refers to the miraculous moment during
pregnancy when the baby is first felt to move. Quickening has
been used in this sense in the English language since 1530.
Quiescent: Inactive, resting. Tuberculosis might be quiescent
Quinacrine: An antimalarial drug and, in cytogenetics, a
fluorescent dye used to stain chromosomes. The Y chromosome
stains brilliantly with quinacrine.
Quincke's disease: This is angioneurotic edema (or angioedema),
a form of localized swelling of the deeper layers of the skin
and fatty tissues beneath the skin. Hereditary angioneurotic
edema (or hereditary angioedema) is a genetic form of angioedema.
Persons with it are born lacking an inhibitor protein (called C1
esterase inhibitor) that normally prevents activation of a
cascade of proteins leading to the swelling of angioedema.
Patients can develop recurrent attacks of swollen tissues, pain
in the abdomen, and swelling of the voice box (larynx) which can
compromise breathing. The diagnosis is suspected with a history
of recurrent angioedema. It is confirmed by finding abnormally
low levels of C1 esterase inhibitor in the blood. Treatment
options include antihistamines and male steroids (androgens)
that can also prevent the recurrent attacks.
Quinine: A classic antimalarial agent, quinine took its name
from the Peruvian Indian kina meaning bark of the tree (they
called it the fever tree), the cinchona tree from which quinine
was first gained.
Quinsy: Not a TV detective but an old word for a peritonsillar
Quintan fever: A louse-borne disease first recognized in the
trenches of World War I (and so called trench fever), again a
major problem in the military in World War II, seen endemically
in Mexico, N. Africa, E, Europe, and elsewhere. The cause,
Rochalimaea quintana, is an unusual rickettsia that multiplies
in the gut of the body louse. Transmission to people can occur
by rubbing infected louse feces into abraded (scuffed) skin or
conjunctiva (whites of the eyes). Onset of symptoms is sudden,
with high fever, headache, back and leg pain and a fleeting
rash. Recovery takes a month or more. Relapses are common.
Quintan means recurring every 5 days and refers to the fever.
Also called five-day fever. Other names include Wolhynia fever,
shin bone fever, Meuse fever, His’ disease, His-Werner disease,
Quotidian: Recurring each day, as in a fever that returns every
day. From the Latin quotidianus for daily. (In French, the noun
quotidien is a daily newspaper.
Quotient: The result of mathematical division. The I.Q.
(Intelligence Quotient) is arrived at by dividing the person's
mental age (as determined on the Binet test) by the person's
chronologic age and multiplying by 100. So if a child scores at
the 8-year old level but is only 6, the I.Q. is 8/6 X 100=125.