Abbreviation for yocto-.
Y (in chemistry)
Y (in chemistry): The symbol
for the element yttrium, an ultrarare metal named after Ytterby
in southern Sweden. Yttrium has been used in certain nuclear
Y (in genetics)
Y (in genetics): The Y
chromosome, the sex chromosome found in normal males, together
with an X chromosome.
a single fluorescent spot originating in the long arm of the Y chromosome and visible in somatic nuclei of buccal smears.
the connecting cartilage for the ilium, ischium, and pubis; it extends through the acetabulum.
Alternate names: hypsiloid cartilage
Y chromatin: Brilliantly
fluorescent body seen in cells stained with the dye quinacrine
which lights up the Y chromosomes most brightly.
Y chromosome: The sex
chromosome found in normal males, together with an X chromosome.
Once thought to be a genetic wasteland, the Y now is known to
contain at least 20 genes, some of them unique to the Y including
the male-determining gene and male fitness genes that are active
only in the testis and are thought responsible for the formation
of sperm. Other genes on the Y have counterparts on the X
chromosome, are active in many body tissues and play crucial
"housekeeping" roles with the cell.
Y map: The array of genes on
the Y chromosome. Once thought to be a genetic wasteland, the Y
now is known to contain at least 20 genes, some of them unique to
the Y including the male-determining gene and male fitness genes
that are active only in the testis and are thought responsible
for the formation of sperm. Other genes on the Y have
counterparts on the X chromosome, are active in many body tissues
and play crucial "housekeeping" roles with the cell.
the negative wave in the atrial and venous pulse curves reflecting rapid filling of the ventricles just after the atrioventricular valves open.
Abbreviation for yocto-.
Abbreviation for yocto-.
in craniometry, the angle at the inion formed by lines drawn from the hormion and the lambda.
Alternate names: hypsiloid angle
a cephalometric indicator of the vertical and horizontal coordinates of mandibular growth expressed in degrees of the inferior facial angle formed by the intersection of the sella-gnathion plane with the Frankfort horizontal plane.
The state of a genetic factor (gene)'s being borne on the Y chromosome. This idea is analogous with X-linkage, but given that the Y chromosome does not fully take part in chiasma formation and recombination, it is not amenable to analysis by conventional linkage methods. Little is known about its content. There is a gene for the H-Y antigen, and indirect arguments suggest that there is a principle that determines the formation of the testis and masculinization of the fetus but its localization, although narrowing the limits, remains elusive.
Y-linked: A gene on the Y
chromosome. A Y-linked gene is by necessity passed from father to
a gene located on a Y chromosome.
Alternate names: holandric gene
Y-linked inheritance: Inheritance
by genes on the Y chromosome. Also called holandric inheritance.
any (haploid) locus that in normal karyotypes is borne on the Y chromosome. The known content is so far small.
a poxvirus from the Yatapoxvirus, family Poxviridae, distinct from monkeypox virus, which causes Yaba tumors in monkeys.
Alternate names: Yaba monkey virus
YAC: Yeast artificial
Abbreviation and acronym for yttrium-aluminum-garnet.
Yag laser surgery
Yag laser surgery: The use of a laser to punch a
hole in the iris to
increased pressure within the eye as, for example, from
glaucoma. Yag laser surgery is an office procedure.
Yang-Monti catheterizable channel
A variant of the Mitrofanoff procedure in which a short segment of bowel is reconfigured into a long tube positioned between bladder and skin to permit intermittent catheterization.
See Also: Mitrofanoff, appendicovesicostomy
A Fijian drink made from the powdered root of Piper methysticum (family Piperaceae); excessive drinking of it causes a state of hyperexcitability and a loss of power in the legs; chronic intoxication induces roughening of the skin and a state of debility.
Alternate names: kava2, kava kava, yanggona
See Also: methysticum
Yard: In length, 3 feet or 36
inches or, metrically, 86.44 centimeters. The yard, along with
the foot and inch, are English creations to which the USA has
stubbornly clung. The yard was originally a unit of measurement
of land and was about 5 meters (now termed a rod). In the 14th
century, the yard emerged as 3 feet, about the length of a riding
stick or sword.
Japanese term (“wild hare disease”) for tularemia.
Alternate names: Ohara disease
An individual lesion of an eruption of yaws.
Yawn: Involuntary opening of
mouth often caused by suggestion and accompanied by breathing
inward then outward. Repeated yawning can be a sign of drowsiness
The act of producing a yawn.
Alternate names: oscitation
Yaws: A common chronic infectious disease that
occurs mainly in the warm humid regions of the tropics with
characteristic bumps on the skin of the face, hands, feet and genital
area. Almost all cases of yaws are in children under 15 years of
The organism that causes yaws is a spirochete. It is spiral
shaped, as are all spirochetes, and is termed Treponema pertenue. (A
different type of spirochete, Treponema pallidum, is the
organism responsible for syphilis).
Yaws begins when the spirochete enters the skin at a spot where it
was scraped, cut or otherwise compromised. At that site a painless
bump arises and grows. It is the mother yaw. The glands in that area
are often swollen (regional lymphadenopathy). The mother yaw heals,
leaving a light-colored scar.
The mother yaw is followed by recurring ("secondary") crops of
bumps and more swollen glands. These bumps may be painless like the
mother yaw or they may be filled with pus, burst and ulcerate.
In its late ("tertiary") stage, yaws can destroy areas of the skin
and bones and joints and deform them. The palms and soles tend to
become thickened and painful ("dry crab yaws").
The diagnosis of yaws comes to the fore in any child who has the
characteristic clinical features and lives in an area where the
disease is common. With increasing travel, a child once
in the tropics may carry the disease to a more temperate clime.
Confirmation of the diagnosis is by blood tests and by special (dark-
field) examination under the microscope (to see the spirochete).
Treatment of yaws is simple and highly effective. A single shot of
penicillin cures the disease. Anyone allergic to penicillin can be
treated with another antibiotic, usually erythromycin or
Yaws is a major public health problem in the tropics. Tropical
regions in Central and South America, Africa, Asia, and Polynesia are
at risk for yaws. A high percentage of children can be infected.
Transmission of the disease is facilitated by overcrowding and poor
hygiene, in the favellas of the cities of northeastern Brazil.
Yaws can be completely eradicated from an area by giving
penicillin or another appropriate antibiotic to everyone in the
population. This may, unfortunately, cost more than a poor country
The term "yaws" is of Caribbean origin. Because the bumps of yaws
look like little berries, the disease is also called frambesia (or
frambesia tropica) from the French "framboise" meaning "raspberry."
Other names include granuloma tropicum polypapilloma tropicum, and