scholarly journals Methodology for Measuring Steady‐State Glomerular Filtration Rate (GFR) Using Continuous Intravenous Infusion of FITC‐Inulin in Conscious Mice

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
B Bivona ◽  
S Park ◽  
L M Harrison‐Bernard
Keyword(s):  
Glomerular Filtration Rate ◽  
Steady State ◽  
Glomerular Filtration ◽  
Intravenous Infusion ◽  
Filtration Rate ◽  
Continuous Intravenous Infusion

scholarly journals Sickle Cell Nephropathy and Associated Factors among Asymptomatic Children with Sickle Cell Anaemia

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Uchenna Modestus Nnaji ◽  
Christian Chukwukere Ogoke ◽  
Henrietta Uche Okafor ◽  
Kingsley I. Achigbu
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Steady State ◽  
Glomerular Filtration ◽  
Sickle Cell ◽  
Filtration Rate ◽  
Sickle Cell Anaemia ◽  
Asymptomatic Children ◽  
Increased Risk ◽  
Sickle Cell Nephropathy

Background. Sickle cell nephropathy (SCN) is a serious complication of sickle cell anaemia (SCA) with asymptomatic onset in childhood and possible progression to chronic kidney disease (CKD). In Southeast Nigeria, few studies have evaluated renal function in paediatric SCA patients for early detection of renal impairment and early intervention to reduce morbidity and mortality. Therefore, this study evaluated the renal function of paediatric SCA patients in a steady state based on glomerular filtration rate and urinalysis findings (proteinuria and haematuria). Methods. A cross-sectional study of consecutively recruited sixty haemoglobin SS (HbSS) children in a steady state and sixty age- and sex-matched haemoglobin AA (HbAA) controls aged 2–18 years was done. Renal function of HbSS subjects was evaluated using estimated glomerular filtration rate (eGFR) which was compared with healthy HbAA subjects. The prevalence of significant proteinuria and haematuria, its association with eGFR, and the effect of past sickle cell crisis (in the preceding 24 months) on renal function were also evaluated. Results. Mean eGFR was significantly higher in HbSS subjects than in the HbAA subjects (p=0.001) and decreased with age. Significant proteinuria and haematuria were more prevalent in the HbSS group (3.4% and 6.7%, respectively) compared to the HbAA subjects (0% and 0%, respectively) (p=0.496 and 0.119, respectively). No significant association was observed between eGFR and proteinuria (p=1.000) or haematuria (p=1.000). There was a positive correlation between eGFR and frequency of past painful crisis that required hospitalization (r=0.138, p=0.295) and between eGFR and frequency of blood transfusion (r=0.679, p≤0.001). Conclusions. Asymptomatic paediatric HbSS (SCA) patients had higher mean eGFR indicating an increased risk of nephropathy. There was no association between eGFR and proteinuria or haematuria. Frequent sickle cell crises especially one requiring transfusion were positively correlated with hyperfiltration.

Transient response of glomerular filtration rate and renal blood flow to step changes in arterial pressure

1977 ◽  
Vol 233 (5) ◽  
pp. F396-F402 ◽  
Author(s):  
T. E. Jackson ◽  
A. C. Guyton ◽  
J. E. Hall
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Steady State ◽  
Arterial Pressure ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Hemodynamic Changes ◽  
Proximal Tubular ◽  
Anesthetized Dogs

Measurement of rapid renal hemodynamic changes were made for 90 s in pentobarbital-anesthetized dogs following step increases and decreases in renal arterial pressure between 80 and 120 mm Hg. Transient analysis was used to observe time characteristics of the autoregulatory relationships which are obscured in steadystate measurements. Temporal decoupling of blood flow and glomerular filtration rate (GFR) occurred with both step increases and decreases of arterial pressure. Steady-state autoregulation of blood flow was attained in about 30 s, whereas steady-state autoregulation of GFR was not demonstrably attained even 90 s after the arterial pressure maneuver. The temporal decoupling of renal blood flow and GRR supports the concept of transient involvement of proximal tubular dynamics and efferent resistance changes during acute autoregulation of GFR following step changes in arterial pressure.

Renal water reabsorption during saline and urea osmotic diuresis in the dog

1963 ◽  
Vol 205 (3) ◽  
pp. 477-482 ◽  
Author(s):  
David L. Maude ◽  
Laurence G. Wesson
Keyword(s):  
Glomerular Filtration Rate ◽  
Steady State ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Free Water ◽  
Conscious Dogs ◽  
Water Reabsorption ◽  
Osmotic Diuresis ◽  
Sodium Salts

Free water reabsorption (Twc) was measured in conscious dogs during a long-term, reasonably steady-state osmotic diuresis induced either by sodium salts or by urea. After 4 to 8 hr the original solute was partially replaced by urea or by sodium salts. Both the replacement of sodium salts by urea and the converse procedure were associated with an augmentation in Twc. During sodium diuresis Twc always fell during the first 2 or 3 hr, a change which appeared unrelated to glomerular filtration rate (GFR) or to osmolar clearance. During the course of urea diuresis Twc steadily increased and showed a positive correlation with GFR. A possible basis for such a correlation is discussed.

Glomerular filtration changes during vasotocin-induced antidiuresis in kelp gulls

1988 ◽  
Vol 255 (6) ◽  
pp. R936-R939
Author(s):  
D. A. Gray ◽  
T. Erasmus
Keyword(s):  
Glomerular Filtration Rate ◽  
Linear Relationship ◽  
Glomerular Filtration ◽  
Water Permeability ◽  
Clearance Rate ◽  
Intravenous Infusion ◽  
Filtration Rate ◽  
Plasma Clearance ◽  
Plasma Concentrations ◽  
Arginine Vasotocin

In conscious kelp gulls, intravenous infusion of arginine vasotocin (AVT) at rates of 0.03, 0.1, 0.3, and 1.0 ng.kg-1.min-1 resulted in a linear relationship between the log values of the AVT plasma concentrations (measured by radioimmunoassay) and the infusion rates, which indicated a plasma clearance rate for AVT of 15.4 ml.min-1.kg-1 when endogenous AVT formation is considered. Evaluation of the renal actions of AVT at each dose level showed that antidiuresis was consistently associated with reductions in glomerular filtration rate as well as changes in tubule water permeability. Thus the water-conserving action of plasma AVT on the kelp gull kidney involves contributions from both glomerular and tubular mechanisms over the entire physiological range found in these birds.

Effect of insulin on renal phosphorus handling in the rat: interaction with PTH and nicotinamide

1985 ◽  
Vol 249 (4) ◽  
pp. F610-F618 ◽  
Author(s):  
J. Guntupalli ◽  
A. Rogers ◽  
E. Bourke
Keyword(s):  
Glomerular Filtration Rate ◽  
Steady State ◽  
Parathyroid Hormone ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Insulin ◽  
Direct Evidence ◽  
Fractional Excretion ◽  
Clearance Studies ◽  
Presence And Absence

Previous studies suggested an antiphosphaturic action of insulin. However, effects of parathyroid hormone (PTH), anti-natriuresis, or other variables were not vigorously controlled. Recently it has been suggested that nicotinamide restores phosphaturia in several antiphosphaturic states. Clearance studies were therefore performed in acutely parathyroidectomized rats to test the hypothesis that insulin abolishes the phosphaturic action of PTH and that this effect is prevented by nicotinamide. Superimposition of euglycemic hyperinsulinemia on PTH infusion (plasma insulin 19.1 +/- 2.7 vs. 9.8 +/- 1.1 microU/ml, P less than 0.05) during steady-state Pi excretion decreased fractional excretion (FE) of Pi compared with PTH-infused controls (3.16 +/- 0.61 vs. 18.02 +/- 0.81%, P less than 0.001). Renal cortical NAD+ was lower in the former than the latter group (455 +/- 22 vs. 689 +/- 30 pmol/mg, P less than 0.01). Nicotinamide pretreatment prevented the antiphosphaturic action of insulin and the decrease in cortical NAD+ in both the presence and absence of exogenous PTH. These studies offer direct evidence that in acutely parathyroidectomized rats insulin can abolish the phosphaturic action of PTH, independent of glomerular filtration rate, the filtered loads of Pi and glucose, FENa+, and cAMP excretion, an effect that is prevented by nicotinamide pretreatment. In the absence of nicotinamide pretreatment, superimposition of insulin on PTH infusion was associated with a decrease in renal cortical NAD+. A role for intracellular NAD+, probably indirect, in the antiphosphaturic action of insulin is suggested.

Renal excretion of creatinine in the rat

1961 ◽  
Vol 200 (1) ◽  
pp. 167-169 ◽  
Author(s):  
Lewis Glasser
Keyword(s):  
Glomerular Filtration Rate ◽  
Creatinine Clearance ◽  
Glomerular Filtration ◽  
Simultaneous Measurement ◽  
Intravenous Infusion ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Plasma Concentrations ◽  
Tubular Secretion ◽  
Plasma Creatinine

The exogenous creatinine clearance was measured in rats using a technique of constant intravenous infusion, and was compared with simultaneous measurement of the radioinulin clearance. Creatinine/inulin clearance ratios were significantly higher than unity at plasma concentrations of creatinine less than 150 mg%, indicating tubular secretion of creatinine. At higher plasma creatinine concentrations (150–500 mg%) the clearance ratios were depressed and did not differ significantly from one. It is concluded that at higher plasma creatinine concentrations the exogenous creatinine clearance may be used as an estimate of glomerular filtration rate.

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