pulse-chase experiment

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pulse-·chase ex·per·i·ment

an experiment in which an enzyme, a metabolic pathway, a culture of cells, etc., interacts with a brief addition (pulse) of a labeled compound followed by its removal and replacement (chase) by an excess of unlabeled compound.


1. a rhythmic wave.
2. any leguminous seed used in animal feed or human food. Contain about 20% protein.
3. the beat of the heart as felt through the walls of arteries. What is felt is not the blood pulsing through the arteries but a shock wave, generated by the abrupt ejection of blood from the heart, that travels along the arteries. The arterial pulse wave can be measured by a sphygmograph. The resulting tracing shows ascending and descending limbs.
Enlarge picture
Palpating facial artery pulse in a horse. By permission from Darke P, Kelly DF, Bonagura JD, Color Atlas of Veterinary Cardiology, Mosby, 1995

abdominal pulse
that over the abdominal aorta.
pulse abnormality
includes irregularity of timing and amplitude, large or small amplitude, waterhammer pulse, Corrigan's pulse, dropped pulse, pulse deficit, alternating pulse and many others.
alternating pulse
pulsus alternans; one with regular alteration of weak and strong beats without changes in cycle length.
pulse amplitude
indicative of arterial blood pressure; estimated on the difference of pressure exerted by the fingers to occlude and then reopen the arterial pulse.
anacrotic pulse
one in which the ascending limb of the tracing shows a transient drop in amplitude, or a notch.
anadicrotic pulse
one in which the ascending limb of the tracing shows two small additional waves or notches.
anatricrotic pulse
one in which the ascending limb of the tracing shows three small additional waves or notches.
arterial pulse
the wave of pressure generated by the ejection of blood from the left ventricle into the aorta. Although the size (amplitude) of the pulse depends on the volume ejected it is not the blood passing the finger that is palpated, it is only the pressure wave. The pulse is a good indicator of the heart's activity with respect to amplitude, rate and regularity. It may also provide information on the state of the vessel walls and the efficiency of the aortic semilunar valves. It may be palpated in the median, facial, femoral or coccygeal arteries, the preferred site varying with the species and the occasion.
atrial venous pulse
atriovenous pulse, a cervical pulse having an accentuated 'a' wave during atrial systole, owing to increased force of contraction of the right atrium; a characteristic of tricuspid stenosis.
B-B shot pulse
see water-hammer pulse (below).
bigeminal pulse
one in which two beats occur in rapid succession, the groups of two being separated by a longer interval, usually related to regularly occurring ventricular premature beats.
catadicrotic pulse
catatricrotic pulse
pulse-chase experiment
to study the movement of macromolecules, cells are incubated with a radiolabeled precursor (pulse) and then replaced with unlabeled precursor (chase). The label can be followed as it is incorporated into newly synthesized compounds and through different cellular compartments.
Corrigan's pulse
pulse deficit
the difference between the apical pulse and the radial pulse. Obtained by counting apical beats as heard through a stethoscope over the heart and counting the arterial pulse at the same time. A characteristic of several arrhythmias.
dicrotic pulse
a pulse characterized by two peaks, the second peak occurring in diastole and being an exaggeration of the dicrotic wave.
pulse dosing
the administration of drugs, usually antibiotics or corticosteroids, in a single, large dose which might be repeated after an interval of days. Thought to have the advantage of high tissue levels and fewer of the undesirable side-effects associated with more frequent dosing.
dropped pulse
arrhythmic pulse.
femoral pulse
that which is located at the site where the femoral artery passes through the groin in the femoral triangle; the usual site for palpating the pulse in dogs and cats.
fetal pulse detector
an ultrasound detector based on the Doppler principle used to detect the presence of a living fetus in utero.
funic pulse
the arterial tide in the umbilical cord.
pulse generator
the power source for a cardiac pacemaker system, usually powered by a lithium battery. It supplies electrical impulses to the implanted electrodes. See also pacemaker.
hard pulse
one characterized by high tension.
jerky pulse
see water-hammer pulse (below).
jugular pulse
comprises the movements of the wall of the jugular vein in response to pressure changes in the right atrium. Much more visible if the vein is distended. A reflection of increased pressure in the right atrium or insufficiency of the right A-V valve. A small pulse is normal in most food animals. A large pulse which goes high up the neck when the head is in the normal position, and which is synchronous with the heart cycle and is systolic in time, indicates insufficiency of the right atrioventricular valve.
pulse monitor
a pulse detector which uses the Doppler principle.
paradoxical pulse
one that markedly decreases in amplitude during inspiration.
peripheral pulse
that palpable in the extremities, e.g. legs, neck and head; the usual sites for measuring the pulse rate.
pistol-shot pulse
one in which the arteries are subject to sudden distention and collapse.
pulse pressure
the difference between the systolic and diastolic pressures.
radial pulse
that felt over the radial artery.
pulse rate
the number of pulsations per minute palpable in an artery, usually of a limb. The normal rates per minute for the common domestic animal species are: horses, 30 to 40; young horses up to one year of age, 70 to 80; cattle, 60 to 80; young calves, 100 to 120; sheep and goats, 70 to 120; pigs (heart rate), 60 to 70; dogs, 100 to 130; cats, 110 to 140; adult fowls 250 to 300.
pulse rhythm
regularity of the pulse in time and amplitude.
thready pulse
one that is very fine and barely perceptible.
pulse tracing
tricrotic pulse
trigeminal pulse
one with a pause after every third beat.
undulating pulse
one giving the sensation of successive waves.
vagus pulse
a slow pulse.
venous pulse
the pulsation over a vein.
water-hammer pulse
one in which the artery is suddenly and markedly distended and relaxed. Characteristic of patent ductus arteriosus. Called also Corrigan's, jerky and B-B shot pulse.
wiry pulse
a small, tense pulse.