the HLA is present, it is detected by an
observable colour or other change.
titanium dental implants See im-
plants, dental.
TMJ syndromeSee temporomandibu-
lar joint syndrome.
toadstool poisoningSee mushroom
poisoning.
tobaccoThe dried leaf of the plant NICO-
TIANA TABACUM. Tobacco is used for
smoking, chewing, or as snuff by bil-
lions of people. It contains a variable
percentage of nicotine, and several car-
cinogenic substances. There is a direct
proportion between the amount of to-
bacco used, the period over which it is
used, and the likelihood of cancer.
Smokers are at increased risk of several
types of cancer, including lung cancer,
bladder cancer, kidney cancer, and pan-
creatic cancer (see pancreas, cancer of).
All tobacco users have an increased risk
of cancers of the oral cavity (see mouth
cancer), pharynx (see pharynx, cancer
of), larynx (see larynx, cancer of) and
oesophagus (see oesophagus, cancer of).
tobacco-smokingSee smoking.
tobramycinAn antibiotic drugused to
treat serious infections such as periton-
itis, meningitis, and severe infections of
the lungs, skin, bones, and joints. In
eye-drop form, it is sometimes used to
treat conjunctivitisand blepharitis. High
doses of injected tobramycin may cause
kidney damage, deafness, nausea, vom-
iting,and headache. Any preparation of
tobramycin may cause rash and itching.
tocographyAn obstetric procedure for
recording muscular contractions of the
uterus during childbirth.It is usually
combined with fetal heart monitoring
(see cardiotocography).
tocopherolA constituent of vitamin E.
Four tocopherols (alpha, beta, gamma,
and delta) and several tocopherol deriv-
atives together make up the vitamin.
toddler’s diarrhoeaA common condi-
tion affecting some children for a period
after the introduction of an adult diet. It
occurs because the child is unable to
digest food properly, perhaps because
of inadequate chewing; the diarrhoea
contains recognizable pieces of food.
This diarrhoea is no cause for concern,
and no treatment is needed.
Todd’s paralysisWeakness in part of
the body following some types of epil-
eptic seizure (see epilepsy). The weakness
may last for minutes, hours, or even
days, but there is no lasting effect. The
cause is thought to be temporary dam-
age to the motor cortex (the area of the
brainthat controls movement).
toeOne of the digits of the foot. Each
toe has 3 phalanges(bones), except for
the hallux(big toe), which has 2. The pha-
langesjoin at hinge joints. An artery,
vein, and nerve run down each side of the
toe, and the whole structure is enclosed
in skin with a nail at the top. The main
function of the toes is to maintain bal-
ance during walking. Congenital disorders
include toes missing at birth. (See also
polydactyly; syndactyly; and webbing.)
toenail, ingrowingA painful condi-
tion of a toe (usually the big toe) in
which 1 or both edges of the nailpress
into the adjacent skin, leading to infec-
tion and inflammation. The cause is
usually incorrect cutting of the nail or
wearing tight-fitting shoes. Temporary
pain relief can be obtained by bathing
the foot once or twice daily in a strong,
warm, salt solution, then covering the
nail with a dry gauze dressing. Antibiotics
may be prescribed. In some cases, the
edge of the nail is removed and the nail
bed obliterated to prevent recurrence.
toilet-trainingThe process of teaching
a young child to acquire complete bowel
and bladder control. A child is unlikely to
be completely toilet-trained before age
3 and may normally take much longer
to remain dry at night (see enuresis).
tolbutamideAn oral hypoglycaemic drug
(see hypoglycaemics, oral) used in the
treatment of type 2 diabetes mellitus.
toleranceThe need to take increasingly
higher doses of a drugto obtain the
same physical or mental effect. Toler-
ance develops after taking a drug over a
period of time and usually results either
from the liver becoming more efficient
at breaking the drug down or from body
tissues becoming less sensitive to it.
tolnaftateAn antifungal drugapplied
to the skin to treat, and sometimes pre-
vent, recurrent tineainfections, including
athlete’s foot. In rare cases, tolnaftate
may cause skin irritation or a rash.TITANIUM DENTAL IMPLANTS TOLNAFTATE
T