Ensuring a Minimum Urine Flow Rate during Water Deprivation in Chronic Fasting

1997 ◽  
pp. 48-54 ◽  
Author(s):  
M.L. Halperin ◽  
S.D. Soroka ◽  
M. Gowrishankar ◽  
H.C. Kim ◽  
J.A. Myers ◽  
...  
Keyword(s):  
Flow Rate ◽  
Water Deprivation ◽  
Urine Flow ◽  
Urine Flow Rate

scholarly journals Minimum urine flow rate during water deprivation: Importance of the permeability of urea in the inner medulla

1998 ◽  
Vol 53 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Manjula Gowrishankar ◽  
Ilan Lenga ◽  
Richard Y. Cheung ◽  
Surinder Cheema-Dhadli ◽  
Mitchell Lewis Halperin
Keyword(s):  
Flow Rate ◽  
Water Deprivation ◽  
Urine Flow ◽  
Urine Flow Rate

scholarly journals Minimum urine flow rate during water deprivation: importance of the nonurea versus total osmolality in the inner medulla.

1997 ◽  
Vol 8 (6) ◽  
pp. 880-886
Author(s):  
S D Soroka ◽  
S Chayaraks ◽  
S Cheema-Dhadli ◽  
J A Myers ◽  
S Rubin ◽  
...  
Keyword(s):  
Flow Rate ◽  
Water Conservation ◽  
Water Deprivation ◽  
Interstitial Fluid ◽  
Collecting Duct ◽  
Normal Subjects ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Urea Excretion ◽  
Medullary Collecting Duct

Antidiuretic hormone leads to an increase in the permeability for water and urea in the inner medullary collecting duct. Hence, urea may not be an "effective" osmole in the inner medulla during maximal renal water conservation. Accordingly, the purpose of this study was to evaluate whether differences in the rate of urea excretion would influence maximum renal water conservation in humans. In water-deprived rats, the concentration of urea and total osmolality were somewhat higher in the urine exiting the inner medullary collecting duct than in interstitial fluid obtained from the entire papillary tip. Nevertheless, the "nonurea" (total osmolality minus urea in millimolar terms) osmolality was virtually identical in both locations. Chronically fasted human subjects that were water-deprived for 16 h had a lower rate of urea excretion (71 +/- 7 versus 225 +/- 14 mumol/min) and a somewhat lower urine osmolality (745 +/- 53 versus 918 +/- 20 mosmol/kg H2O). Nevertheless, they had identical urine flow rates (0.5 +/- 0.01 and 0.5 +/- 0.02 ml/min, respectively), and their nonurea osmolality also was similar (587 +/- 25 and 475 +/- 14 mosmol/kg H2O, respectively) to the water-deprived normal subjects. The composition of their urine differed in that the principal nonurea osmoles became NH4+ and beta-hydroxybutyrate rather than Na and C1. During water deprivation in normal subjects, the ingestion of urea caused a twofold rise in urine flow rate, a fall in the nonurea osmolality, and a rise in the rate of excretion of nonurea osmoles. The nonurea osmolality of the urine, and presumably the medullary interstitial fluid as well, was inversely related to the urea excretion rate. In chronic fasting, the nature, but not the quantity, of nonurea osmoles changed. The similar minimum urine volume was predictable from an analysis based on nonurea osmole considerations.

Effect of urine flow rate on uric acid excretion in man

1972 ◽  
Vol 15 (4) ◽  
pp. 338-346 ◽  
Author(s):  
Herbert S. Diamond ◽  
Robert Lazarus ◽  
David Kaplan ◽  
David Halberstam
Keyword(s):  
Uric Acid ◽  
Flow Rate ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Acid Excretion ◽  
Uric Acid Excretion

Homeostatic potassium excretion in fed and fasted sheep

1988 ◽  
Vol 254 (2) ◽  
pp. R357-R380 ◽  
Author(s):  
L. Rabinowitz ◽  
D. M. Green ◽  
R. L. Sarason ◽  
H. Yamauchi
Keyword(s):  
Flow Rate ◽  
Urine Flow ◽  
Plasma Aldosterone ◽  
Urine Flow Rate ◽  
Potassium Excretion ◽  
Adult Sheep ◽  
Blood Ph ◽  
Low Levels ◽  
K Concentration ◽  
Filtered Load

In unanesthetized adult sheep, following intake of a daily meal, there was a peak in K excretion. The maximum and minimum rates of K excretion following meals were directly related to meal K content. On days without meals, no peak in K excretion occurred. Changes in K excretion on fed and fast days occurred without changes in the low levels of plasma aldosterone and were poorly correlated with urine or blood pH, urine flow rate, Na excretion, or the filtered load of K, but they correlated well with fractional K excretion. Plasma K did not change on fast days. Plasma K increased on some, but not all, fed days. Increases in plasma K that occurred on fed days were insufficient to account for the concurrent kaliuresis. Infusion of aldosterone or isotonic NaCl failed to alter K excretion in fed or fasted sheep. Infusion of isotonic NaCl + aldosterone hypertonic Na2SO4 + aldosterone increased K excretion in fasted but not fed sheep. Infusion of K in the rumen of fed and fasted sheep elevated rumen K concentration and led to increases in K excretion that could not be explained by increases in plasma K. The mechanisms responsible for the homeostatic changes in K excretion on fed and fast days were not ascertained but may importantly depend on sensors of enteric K content.

Urine Quantification Following Furosemide for Severe Acute Kidney Injury Prediction in Critically Ill Children

2021 ◽  
Author(s):  
Katja M. Gist ◽  
Jamie Penk ◽  
Eric L. Wald ◽  
Laura Kitzmiller ◽  
Tennille N. Webb ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Cardiac Surgery ◽  
Critically Ill ◽  
Flow Rate ◽  
Kidney Injury ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Critically Ill Children ◽  
Prospective Assessment ◽  
Critically Ill Adults

AbstractA standardized, quantified assessment of furosemide responsiveness predicts acute kidney injury (AKI) in children after cardiac surgery and AKI progression in critically ill adults. The purpose of this study was to determine if response to furosemide is predictive of severe AKI in critically ill children outside of cardiac surgery. We performed a multicenter retrospective study of critically ill children. Quantification of furosemide response was based on urine flow rate (normalized for weight) measurement 0 to 6 hours after the dose. The primary outcome was presence of creatinine defined severe AKI (Kidney Disease Improving Global Outcomes stage 2 or greater) within 7 days of furosemide administration. Secondary outcomes included mortality, duration of mechanical ventilation and length of stay. A total of 110 patients were analyzed. Severe AKI occurred in 20% (n = 22). Both 2- and 6-hour urine flow rate were significantly lower in those with severe AKI compared with no AKI (p = 0.002 and p < 0.001). Cutoffs for 2- and 6-hour urine flow rate for prediction of severe AKI were <4 and <3 mL/kg/hour, respectively. The adjusted odds of developing severe AKI for 2-hour urine flow rate of <4 mL/kg/hour was 4.3 (95% confidence interval [CI]: 1.33–14.15; p = 0.02). The adjusted odds of developing severe AKI for 6-hour urine flow rate of <3 mL/kg/hour was 6.19 (95% CI: 1.85–20.70; p = 0.003). Urine flow rate in response to furosemide is predictive of severe AKI in critically ill children. A prospective assessment of urine flow rate in response to furosemide for predicting subsequent severe AKI is warranted.

Renal Function in Unanaesthetized River Lampreys (Lampetra FluviatilisL.): Effects of Anaesthesia, Temperature and Environmental Salinity

1983 ◽  
Vol 105 (1) ◽  
pp. 351-362 ◽  
Author(s):  
A. J. MCVICAR ◽  
J. C. RANKIN
Keyword(s):  
Renal Function ◽  
Flow Rate ◽  
Ventilation Rate ◽  
Urine Flow ◽  
The Body ◽  
Urine Flow Rate ◽  
Flow Rates ◽  
Gill Ventilation ◽  
Daily Excretion ◽  
The Mean

1. Improved estimates of urine flow rates of lampreys in various salinities were obtained by the collection of urine for periods of up to 48 h from minimally-stressed, unanaesthetized fish, following catheterization of the urinogenital papilla. 2. The mean urine flow rate of freshwater lampreys was 200.7 ±14.3 ml kg−1 day−1. 3. Urine flow in freshwater lampreys was correlated with spontaneous changes in gill ventilation rate. MS222 anaesthesia reduced both ventilation and urine flow rates, but pronounced effects were only observed at concentrations greater than those needed to induce light anaesthesia (50–55 mg 1−1). Urine flow rate in unanaesthetized fish was extremely sensitive to rapid (6°Ch−1) changes in temperature and Q10 (6–16°C) was approximately 5. 4. Urine flow rate decreased rapidly as the osmotic difference between the body fluids and environment approached zero, and the rate of flow in 30% seawater lampreys was only 7.6% that of freshwater fish. 5. There was no evidence for an effect of environmental calcium concentration on branchial osmotic permeability. 6. Extensive tubular reabsorption of ions occurred in freshwater lampreys. The total daily excretion rate of sodium ions generally decreased in salinities hyperosmotic to the plasma, indicating enhanced reabsorption, but secretion of magnesium and sulphate ions was greatly increased. Urine osmolarity was significantly increased in lampreys in hyperosmotic salinities. 7. Present data compare favourably with data obtained previously from anaesthetized animals, indicating that renal function in lampreys is not significantly impaired by light MS222 anaesthesia.

Renal function in the chronically cannulated fetal llama: comparison with studies in the ovine fetus

1995 ◽  
Vol 7 (5) ◽  
pp. 1311 ◽  
Author(s):  
EM Wintour ◽  
R Riquelme ◽  
C Gaete ◽  
C Rabasa ◽  
E Sanhueza ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Flow Rate ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Fetal Kidney ◽  
Fetal Plasma ◽  
Post Surgery ◽  
Fetal Urine ◽  
Ovine Fetus ◽  
Ovine Fetal

Samples of maternal and fetal plasma, fetal urine, and amniotic fluid were collected from 8 chronically cannulated pregnant llamas, in the last third of gestation. The samples were obtained for up to 18 days post-surgery. Osmolality, sodium (Na), potassium (K), chloride (Cl), and urea were measured on 40 samples collected on days 1, 2, 3, 4-5, 6-7, 8-9, and 10-19. The osmolalities of maternal and fetal plasma, fetal urine and amniotic fluid, averaged over these 7 time periods, were, respectively, 312 +/- 2, 311 +/- 1, 484 +/- 14, and 317 +/- 1 mosmol kg-1. Values are given as mean +/- s.e. The major differences from fetal fluid values in the ovine fetus (from previously published values) were the higher osmolality and urea concentration of llama fetal urine. Urine flow rate measured in 6 fetuses, 4.5-6.5 kg body weight, was 5.8 +/- 0.4 mliter h-1; urea clearance rate was 55.5 +/- 11.8 mliter h-1. Glomerular filtration rate (GFR), measured with 51Cr-EDTA in 5 fetuses on 1-4 occasions, was 111.4 +/- 23.3 mliter h-1. Fractional reabsorptions (FR) of Na, K and Cl were 97.9 +/- 1, 75.9 +/- 13.5 and 97.7 +/- 0.4% respectively. The GFR (25 mliter kg-1 h-1) and urine flow rate (1 mL kg-1 h-1) were less than half and about one-tenth the respective values in ovine fetuses. As Na reabsorption is the major oxygen-consuming activity of the kidney, the llama fetal kidney requires only half the oxygen needed by the ovine fetal kidney to reabsorb the filtered sodium load. The reason for the formation of hypertonic, rather than hypotonic, urine in the fetal llama may be due to both greater morphological maturity of the kidney and the excretion of as yet unidentified osmotically active organic substances.

Trout vascular and renal responses to atrial natriuretic factor and heart extracts

1986 ◽  
Vol 251 (3) ◽  
pp. R639-R642 ◽  
Author(s):  
D. W. Duff ◽  
K. R. Olson
Keyword(s):  
Flow Rate ◽  
Atrial Natriuretic Factor ◽  
Pressor Response ◽  
Aortic Pressure ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Natriuretic Factor ◽  
Long Duration ◽  
Before And After ◽  
Atrial Natriuretic

Dorsal aortic pressure (DAP), urine flow rate, and urinary K+, Na+, and Cl- were monitored in chronically catheterized unanesthetized rainbow trout before and after injection of saline, tissue extracts, or synthetic (rat, Ile-26) atrial natriuretic factor (ANF). Synthetic ANF (1.0 and 10.0 micrograms/kg body wt) and extracts from trout atria and ventricles increased DAP, urine flow rate, and electrolyte excretion. Saline, skeletal muscle extracts, and 0.1 microgram/kg body wt synthetic ANF had no effect on DAP and only minor effects on renal water and ion excretion. The slow-onset long-duration pressor response to ANF and heart extracts contrasted with a rapid short-acting pressor effect of epinephrine. Synthetic ANF (10 micrograms/kg body wt) and ventricular extracts produced marked increases in Na+ and Cl- excretion but only a mild diuresis. Much of the increase in urine flow rate appears to be due to solvent injection. These results show that trout hearts contain an ANF-like material and that mammalian and piscine ANF produce hemodynamic and renal effects upon intra-arterial injection.

Effect of urine flow rate on urea reabsorption in man: urea as a "tubular marker"

1969 ◽  
Vol 26 (5) ◽  
pp. 594-599 ◽  
Author(s):  
M. H. Goldstein ◽  
P. R. Lenz ◽  
M. F. Levitt
Keyword(s):  
Flow Rate ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Urea Reabsorption

scholarly journals A new procedure for analysis and modelling of male urine flow rate

2015 ◽  
Author(s):  
Rui Li ◽  
Andrew Gammie ◽  
Zhu Quanmin ◽  
Mokhtar Nibouche ◽  
Janice Kiely
Keyword(s):  
Flow Rate ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Male Urine
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