| fluctuation | 1. A motion like that of waves; a moving in this and that direction; as, the fluctuations of the sea. 2. A wavering; unsteadiness; as, fluctuations of opinion; fluctuations of prices. 3. <medicine> The motion or undulation of a fluid collected in a natural or artifical cavity, which is felt when it is subjected to pressure or percussion. Origin: L. Fluctuatio; cf. F. Fluctuation. Source: Websters Dictionary (01 Mar 1998) |
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| fluctuation analysis | Method used to determine (for example) how many ion channels contribute to the transmembrane current. On the assumption that each channel is either open or shut, the noise in the recorded current can be considered to arise from the statistical fluctuation in the number of channels open and the magnitude of the fluctuation gives an estimate of the conductance of a single channel. (18 Nov 1997) |
| fluctuation test | <investigation> Test devised by Luria and Delbruck to determine whether genetic variation in a bacterial population arises spontaneously or adaptively. In the original version the statistical variance in the number of bacteriophage resistant cells in separate cultures of bacteriophage sensitive cells was compared with variance in replicate samples from bulk culture. The greater variance in the isolated populations indicates that mutation occurs spontaneously before challenge with phage. (The proportion of resistant cells depends upon when after isolation the mutation arises which will be very different in separate populations). (18 Nov 1997) |
| blood pressure | <cardiology, physiology> The force that the circulating blood exerts on the walls of the arteries. This measurement is divided into systolic (pressure during contraction of the heart) and diastolic (pressure during relaxation phase). Blood pressure varies with age and sex of the individual. A rough rule of thumb for normal systolic pressure is 100 + Age of individual. In children 2 x (age) + 80 = systolic BP The diastolic pressure should be roughly 2/3 the systolic pressure. (27 Sep 1997) |
| blood pressure determination | Techniques for measuring blood pressure. (12 Dec 1998) |
| blood pressure, high | High blood pressure (hypertension) is a repeatedly elevated blood pressure exceeding 140 over 90 mmHg. High blood pressure is also called the silent killer. Chronically high blood pressure can cause blood vessel changes in the back of the eye (retina), thickening of the heart muscle, kidney failure, and brain damage. No specific cause for high blood pressure is found in 95% of patients. High blood pressure is treated with salt restriction, regular aerobic exercise, and medications. (12 Dec 1998) |
| blood pressure monitoring, ambulatory | Method in which prolonged blood pressure readings are made while the patient undergoes normal daily activities. It allows quantitative analysis of the high blood pressure load over time, can help distinguish between types of hypertension, and can assess the effectiveness of antihypertensive therapy. (12 Dec 1998) |
| blood pressure monitors | Devices for continuously measuring and displaying the arterial blood pressure. (12 Dec 1998) |
| high blood pressure | <cardiology> Persistently high arterial blood pressure. Hypertension may have no known cause (essential or idiopathic hypertension) or be associated with other primary diseases (secondary hypertension). This condition is considered a risk factor for the development of heart disease, peripheral vascular disease, stroke and kidney disease. (29 Sep 1997) |
| systolic blood pressure | <cardiology, physiology> The pressure exerted on the walls of the arteries during the contraction phase of the heart. Considered abnormally elevated if consistently over 150 mmHg. Systolic blood pressure varies with age, sex, size and relative condition. (27 Sep 1997) |
| diastolic blood pressure | The pressure exerted on the walls of the arteries when the heart is in the relaxation phase (diastole). Considered abnormally elevated if consistently over 90 mmhg. (27 Sep 1997) |
| differential blood pressure | The arterial blood pressure at corresponding points on the two sides of the body. (05 Mar 2000) |
| abdominal pressure | Pressure surrounding the bladder; estimated from rectal, gastric, or intraperitoneal pressure. (05 Mar 2000) |
| absolute pressure | Pressure measured with respect to zero pressure. Compare: gauge pressure. (05 Mar 2000) |
| acoustic pressure | In ultrasound, the instantaneous value of the total pressure minus the ambient pressure; unit is pascal (Pa). (05 Mar 2000) |