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Palliative: Serving to relieve or alleviate without curing.
Palpate:
To examine by touch or feel.
Palpitaion: The fluttering of the heart or abnormal rate of rhythm
of the heart.
Pancreas:
A small organ located behind the stomach. The head of the pancreas is
connected to the duodenum (the first section of the small intestine). The
pancreas makes enzymes that help digest food in the small intestine and
hormones, including insulin, that control the amount of glucose in the
blood.
Parathyroid glands: Glands located behind the thyroid gland in the neck.
The parathyroid glands secrete a hormone called parathormone (PTH) that is
critical to calcium and phosphorus metabolism.
Parkinson's disease: A disease of the nervous system caused by
degeneration of a part of the brain called the basal ganglia, and by low
production of the neurotransmitter dopamine. Symptoms include muscle
rigidity, tremors, and slow voluntary movement.
Pathogen:
Disease causing agent, such as a virus or a bacteria.
Peptic ulcer disease:
A disease characterized by ulcers
or breaks in the inner lining (mucosa) of the stomach or duodenum (region of
the small intestine closest to the stomach). The three major causes of
peptic ulcer disease are non-steroidal anti-inflammatory drugs (NSAIDS),
chronic Heliobacter pylori infection, and states of acid hypersecretion,
like Zollinger-Ellison syndrome.
Peptide: A
chain of amino acids. A protein is made up of one or more peptides.
Peptide hormones: Hormones
that are proteins, as opposed to steroid hormones, which are made from
cholesterol. Insulin is an example of a peptide hormone.
Peripheral vascular diseases: Diseases
of the vessels of the extremities such as atherosclerosis, resulting in
diminished circulation, pain (claudication), or a blood clot, for example.
Pernicious anemia: The
end stage of an autoimmune inflammation of the stomach, resulting in
destruction of stomach cells by one's own antibodies. Progressive
destruction of the cells that line the stomach cause decreased secretion of
acid and enzymes required to release food bound vitamin B-12. Antibodies to
intrinsic factor (IF) bind to IF preventing formation of the IF-B-12
complex, further inhibiting vitamin B-12 absorption.
PET
scan: Positron
emission tomography. A diagnostic imaging technique that uses a
sophisticated camera and computer to produce images of how a person's body
is functioning. A PET scans shows the difference between healthy and
abnormally functioning tissues.
pH:
A measure of
acidity or alkalinity.
Pharmacologic dose: The
dose or intake level of a nutrient many times the level associated with the
prevention of deficiency or the maintenance of health. A pharmacologic dose
is generally associated with the treatment of a disease state and considered
to be a dose at least 10 times greater than that needed to prevent
deficiency.
Phenylketonuria (PKU): An
inherited disorder resulting in the inability to process the amino acid,
phenylananine. If not treated, the disorder may result in mental
retardation. Treatment is a diet low in phenylalanine. Newborns are screened
for PKU, in order to determine the need for treatment before brain damage
occurs.
Phlebotomy: The
removal of blood from a vein. Phlebotomy may be used to obtain blood for
diagnostic tests or to treat certain conditions, for example, iron overload
in hemochromatosis.
Phospholipids:
Lipids (fat molecules) in which
phosphoric acid as well as fatty acids are attached to a glycerol backbone.
Phospholipids are found in all living cells and in the bilayers of cell
membranes.
Phosphorylation: The
creation of a phosphate derivative of an organic molecule. This is usually
achieved by transferring a phosphate group (-PO4) from ATP to
another molecule.
Physiologic dose: The
dose or intake level of a nutrient associated with the prevention of
deficiency or the maintenance of health. A physiologic dose of a nutrient
is not generally greater than that which could be achieved through a
conscientious diet, as opposed to the use of supplements.
Pituitary gland: A
small oval gland located at the base of the brain that secretes hormones
regulating growth and metabolism. The pituitary gland is divided into two
separate glands, the anterior and posterior pituitary glands, which each
secrete different hormones.
Placebo: A
sugar pill or false treatment that is given to a control group while the
experimental group is given the experimental treatment. Placebo-controlled
studies are conducted to make sure that significant outcomes of a trial are
due to the experimental treatment rather than another factor associated with
participating in the study.
Placenta: A
temporary organ joining the mother and unborn child (fetus). The placenta
transfers oxygen and nutrients from the mother to the fetus, and permits the
release of carbon dioxide and waste products from the fetus.
Placental abruption: Premature
separation of the placenta from the wall of the uterus. Abruption is a
potentially serious problem both for the mother and baby.
Plasma: The
liquid part of blood (as opposed to blood cells) that makes up about half
its volume. Plasma differs from serum in that the blood sample has not
clotted. A centrifuge is used to separate plasma from cells in the
laboratory.
Platelet: Irregularly
shaped cell fragments that assist in blood clotting. During normal blood
clotting platelets aggregate (group together) to prevent hemorrhage.
Pneumonia: A
disease of the lungs, characterized by inflammation and accumulation of
fluid in the lungs. Pneumonia may be caused by infectious agents (e.g.,
viruses or bacteria) or by inhalation of certain irritants.
Polymorphism: The
existence of two (or more) forms of a gene with each form being too common
to be due merely to new mutation.
Polyp:
A benign (non-cancerous)
mass of tissue that forms on the inside of a hollow organ, such as the
colon.
Precursor:
A molecule which is an
ingredient, reactant, or intermediate in a synthetic pathway for a
particular product.
Preeclampsia: A
condition characterized by a
sharp rise in blood pressure during the third trimester of pregnancy. High
blood pressure may be accompanied by edema (swelling), and kidney problems,
as evidenced by protein in the urine. Although preeclampsia is relatively
common, occurring in about 5 percent of all pregnancies and more frequently
in first pregnancies, it can be a sign of serious problems. In some cases,
untreated preeclampsia can progress to eclampsia, a life-threatening
situation for both mother and baby.
Prevalence: The
proportion of a population with a specific disease or condition at a given
point in time.
Prognosis
: Predicted outcome based
on the course of a disease.
Proliferation: Rapid
cell division.
Prooxidant: An
atom or molecule that promotes oxidation of another atom or molecule by
accepting electrons. Examples of prooxidants include free radicals, reactive
oxygen species (ROS) and reactive nitrogen species (RNS).
Prophylaxis: Prevention,
often refers to a treatment used to prevent a disease.
Prospective study: A
study in which participants are initially enrolled, examined or tested for
risk factors (e.g., nutrient intake), and then followed up at subsequent
times to determine their status with respect to the disease or condition of
interest.
Prostaglandin: Any
of a class of hormone-like, regulatory molecules constructed from
polyunsaturated fatty acids such as arachidonate. These molecules
participate in a number of functions in the body, such as smooth muscle
contraction and relaxation, vasodilation, and kidney regulation.
Prostate: A
gland situated at the beginning of the urethra (passage through which urine
leaves the body) in men. It secretes an alkaline fluid which is the major
component of semen (ejaculatory fluid). Prostate cancer is the second
leading cause of death in men in the U.S.
Protein: A
complex organic molecule composed
of amino acids in a specific order. The order is determined by the sequence
of nucleic acids in a gene coding for the protein. Proteins are required for
the structure, function, and regulation of the body's cells, tissues, and
organs, and each protein has unique functions.
Proteoglycan: A
large compound comprised of protein and polysaccharide units known as
glycosaminoglycans (GAGs). GAGs are polymers of sugars and amino sugars,
such as glucosamine or galactosamine. Proteoglycans are integral components
of structural tissues such as bone and cartilage.
Psoriasis:
A chronic skin condition often
resulting in a red, scaly rash located over the surfaces of the elbows,
knees, scalp, and around or in the ears, navel, genitals or buttocks.
Approximately 10-15% of patients with psoriasis develop joint inflammation
(psoriatic arthritis). Psoriasis is thought to be an autoimmune condition.
Pyruvate kinase deficiency: A
hereditary deficiency of the enzyme pyruvate kinase. Pyruvate kinase
deficiency results in hemolytic anemia.
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