Validation of ‘Transit Renography’ for the Determination of the Intrarenal Distribution of Plasma Flow: Comparison with the Microsphere Method in the Anaesthetized Rabbit and Pig

1978 ◽  
Vol 55 (3) ◽  
pp. 277-283 ◽  
Author(s):  
S. P. Wilkinson ◽  
M. Bernardi ◽  
P. C. Pearce ◽  
K. E. Britton ◽  
N. J. G. Brown ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Plasma Flow ◽  
Close Agreement ◽  
Distribution Curve ◽  
Flow Distribution ◽  
Transit Times ◽  
Microsphere Method ◽  
Frequency Distribution Curve ◽  
Intrarenal Distribution

1. The spectrum of transit times of sodium o-iodohippurate (Hippuran) through the kidney can be derived from an 131I- (or 123I-) labelled Hippuran renogram by deconvolution. In the rabbit and pig, as has previously been shown in man, the frequency distribution curve for the transit times was bimodal. Since the transit time is likely to be proportional to the nephron length, the area of the first mode is likely to represent plasma flow to the shorter outer cortical nephrons whereas the delayed mode represents flow to the long juxtamedullary nephrons. 2. This interpretation was tested by simultaneously comparing renography with the microsphere method of measuring intrarenal plasma flow distribution in 12 rabbits and two pigs with a variety of anaesthetics. A close agreement was found between both methods for the percentage of plasma flow distributed to the outer cortical nephrons, thus supporting the use of ‘transit renography’ to determine the intrarenal distribution of plasma flow.

Comparison of dye-dilution and flowmeter estimates of pulmonary valve incompetence in dogs

1960 ◽  
Vol 15 (3) ◽  
pp. 465-472 ◽  
Author(s):  
P. I. Korner ◽  
J. B. Uther ◽  
J. P. Chalmers ◽  
R. Nicks
Keyword(s):  
Distribution Curve ◽  
Pulmonary Valve ◽  
Regression Equations ◽  
Forward Flow ◽  
Pooled Data ◽  
Quantitative Estimates ◽  
Single Determination ◽  
Frequency Distribution Curve ◽  
Good Agreement

Quantitative estimates of backflow were obtained in dogs with experimental pulmonary valve incompetence by means of a bristle flowmeter and the dye curve variance method. The variance of the curve was found to be the best index of indicator dispersion and is calculated from analogy to a frequency distribution curve. The method postulates that (forward flow + backflow)/forward flow = variance observed during incompetence/Vx(F; V), where Vx(F; V) is the expected variance for the same forward flow and volume between injection and sampling sites and is determined from regression equations calculated from data of normal dogs. There was good agreement between dye and flowmeter results, provided that Vx(F2;V) was estimated for the specific regression equations obtained from individual dogs. Three or four successive dye curves, obtained while the animal was in a steady state, permitted quantitation of backflow with the accuracy of a single determination of forward flow by the direct Fick or dye method. When Vx(F;V) was estimated from regression equations obtained from the pooled data and normal dogs, agreement with the flowmeter estimates was poor. Submitted on October 28, 1959

Intrarenal Distribution of Plasma Flow in Cirrhosis as Measured by Transit Renography: Relationship with Plasma Renin Activity, and Sodium and Water Excretion

1977 ◽  
Vol 52 (5) ◽  
pp. 469-475 ◽  
Author(s):  
S. P. Wilkinson ◽  
I. K. Smith ◽  
M. Clarke ◽  
V. Arroyo ◽  
J. Richardson ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Flow ◽  
Free Water ◽  
Plasma Renin ◽  
Renal Perfusion ◽  
Renin Activity ◽  
Water Excretion ◽  
Transit Times ◽  
Abnormal Pattern ◽  
Intrarenal Distribution

1. The intrarenal distribution of plasma flow was determined with a technique based on the analysis of the transit time of sodium o-[131I]-iodohippurate through the kidney in 43 patients with cirrhosis with near-normal total renal perfusion. 2. Twenty-five of the patients had an abnormal pattern of transit times, suggesting a redistribution of plasma flow from outer cortical to juxtamedullary nephrons. 3. Plasma renin activity ranged from below normal to six times normal and high values were found only in patients showing an abnormal pattern of transit times. The latter was also found to be related to sodium retention and a reduced renal capacity to excrete free water.

FREQUENCY-DISTRIBUTION CURVE OF URIC ACID IN THE GENERAL POPULATION

The Lancet ◽  
1966 ◽  
Vol 288 (7456) ◽  
pp. 185-187 ◽  
Author(s):  
Ronald Finn ◽  
P.O. Jones ◽  
M.C.K. Tweedie ◽  
SybilM. Hall ◽  
OliveF. Dinsdale ◽  
...  
Keyword(s):  
Uric Acid ◽  
General Population ◽  
Frequency Distribution ◽  
Distribution Curve ◽  
Frequency Distribution Curve

Particle Size of Rubber Globules in Hevea Latex

1952 ◽  
Vol 25 (2) ◽  
pp. 315-320
Author(s):  
M. van den Tempel
Keyword(s):  
Particle Size ◽  
Frequency Distribution ◽  
Distribution Curve ◽  
Average Particle Size ◽  
Average Particle ◽  
Size Frequency Distribution ◽  
Size Frequency ◽  
Asymmetrical Shape ◽  
Frequency Distribution Curve ◽  
Number Of Particles

Abstract 1. The use of visible light in determining the average particle size or the particle-size distribution in Hevea latex renders the results meaningless, as only about 40 per cent of the particles have a diameter of more than 0.2 µ. 2. In considering the size-frequency distribution curve as determined by Lucas, it could be assumed that, actually, the number of particles having a diameter of less than 0.12 µ might be very much larger than has been indicated by him. The agreement with the determination of the number of particles by van Gils, however, may be taken as evidence in favor of the correctness of the curve as given by Lucas. 3. An expression has been given which describes the size-frequency distribution curve, as found by Lucas, with a high degree of accuracy. It is necessary to assume that no particles larger than 5.2 µ are present in the latex. 4. Attention is directed to the considerable difference existing between the various average diameters, caused by the strongly asymmetrical shape of the size-frequency distribution curve. This work forms part of the program of fundamental research on latex problems undertaken by the Research Department of the Rubber-Stichting, Delft, under the management of H. C. J. de Decker.

Sign in / Sign up

Export Citation Format

Share Document