pulse-chase experiment

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.

pulse

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.

Palpating facial artery pulse in a horse. By permission from Darke P, Kelly DF, Bonagura JD, Color Atlas of Veterinary Cardiology, Mosby, 1995

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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

see catadicrotism.

catatricrotic pulse

see catatricrotism.

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

see 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

see sphygmogram.

tricrotic pulse

see tricrotism.

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.