Polyuria and impaired renal blood flow after asphyxia in preterm fetal sheep

2004 ◽  
Vol 286 (3) ◽  
pp. R576-R583 ◽  
Author(s):  
J. S. Quaedackers ◽  
V. Roelfsema ◽  
C. J. Hunter ◽  
E. Heineman ◽  
A. J. Gunn ◽  
...  
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Fractional Excretion ◽  
Analysis Of Covariance ◽  
Tubular Dysfunction ◽  
Renal Tubular Dysfunction ◽  
Fetal Sheep ◽  
Arterial Blood ◽  
Fractional Excretion Of Sodium ◽  
Renal Tubular

Renal impairment is common in preterm infants, often after exposure to hypoxia/asphyxia or other circulatory disturbances. We examined the hypothesis that this association is mediated by reduced renal blood flow (RBF), using a model of asphyxia induced by complete umbilical cord occlusion for 25 min ( n = 13) or sham occlusion ( n = 6) in chronically instrumented preterm fetal sheep (104 days, term is 147 days). During asphyxia there was a significant fall in RBF and urine output (UO). After asphyxia, RBF transiently recovered, followed within 30 min by a secondary period of hypoperfusion ( P < 0.05). This was mediated by increased renal vascular resistance (RVR, P < 0.05); arterial blood pressure was mildly increased in the first 24 h ( P < 0.05). RBF relatively normalized between 3 and 24 h, but hypoperfusion developed again from 24 to 60 h ( P < 0.05, analysis of covariance). UO significantly increased to a peak of 249% of baseline between 3 and 12 h ( P < 0.05), with increased fractional excretion of sodium, peak 10.5 ± 1.4 vs. 2.6 ± 0.6% ( P < 0.001). Creatinine clearance returned to normal after 2 h; there was a transient reduction at 48 h to 0.32 ± 0.02 ml·min-1·g-1(vs. 0.45 ± 0.04, P < 0.05) corresponding with the time of maximal depression of RBF. No renal injury was seen on histological examination at 72 h. In conclusion, severe asphyxia in the preterm fetus was associated with evolving renal tubular dysfunction, as shown by transient polyuria and natriuresis. Despite a prolonged increase in RVR, there was only a modest effect on glomerular function.

Effects of dopamine in the renal vascular bed of fetal, newborn, and adult sheep

1987 ◽  
Vol 252 (3) ◽  
pp. R490-R497 ◽  
Author(s):  
K. T. Nakamura ◽  
R. A. Felder ◽  
P. A. Jose ◽  
J. E. Robillard
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Renal Blood Flow ◽  
Blood Flow Velocity ◽  
Experimental Models ◽  
Dose Ratio ◽  
Fetal Sheep ◽  
Adult Sheep ◽  
Beta Adrenoceptor ◽  
Arterial Blood

The renal hemodynamic response to renal arterial dopamine infusions was compared in unanesthetized fetal (129-137 days gestation, full term 145 days), newborn, and adult sheep. Mean arterial blood pressure and heart rate remained unchanged during intrarenal dopamine infusions. Dopamine produced dose-related decreases in mean renal blood flow velocity in all three groups. When compared with adult sheep fetal sheep were slightly more sensitive to the vasoconstrictive effects of dopamine ED50 (mean effective dose ratio: fetus/ED50 adult = 0.368 +/- 0.047, P less than 0.05). Increases in mean renal blood flow velocity were not seen at any dose given (1-16 micrograms/kg body wt in fetuses, 2-32 micrograms/kg body wt in newborns and adults) until dopamine was infused during alpha- and beta-adrenoceptor blockade. The largest mean increase in renal flow velocity was 13 +/- 3, 16 +/- 3, and 17 +/- 4% in fetal, newborn, and adult sheep, respectively. cis-Flupentixol inhibited the vasodilation. This study demonstrates the presence of renal vasodilation following renal arterial dopamine infusions in fetal, newborn, and adult sheep when renal alpha- and beta-adrenoceptors are blocked. Vasodilator responses are similar in all three groups, and increases in renal blood flow velocity are small compared with that of other experimental models.

Supersensitivity to norepinephrine in chronically denervated kidneys: evidence for a postsynaptic effect

1987 ◽  
Vol 65 (11) ◽  
pp. 2219-2224 ◽  
Author(s):  
J. Krayacich ◽  
R. L. Kline ◽  
P. F. Mercer
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Urine Flow ◽  
Fractional Excretion Of Sodium ◽  
Infusion Of Norepinephrine

Denervation supersensitivity in chronically denervated kidneys increases renal responsiveness to increased plasma levels of norepinephrine. To determine whether this effect is caused by presynaptic (i.e., loss of uptake) or postsynaptic changes, we studied the effect of continuous infusion of norepinephrine (330 ng/min, i.v.) and methoxamine (4 μg/min, i.v.), an α1 adrenergic agonist that is not taken up by nerve terminals, on renal function of innervated and denervated kidneys. Ganglionic blockade was used to eliminate reflex adjustments in the innervated kidney and mean arterial pressure was maintained at preganglionic blockade levels by an infusion of arginine vasopressin. With renal perfusion pressure controlled there was a significantly greater decrease in renal blood flow (−67 ± 9 vs. −33 ± 8%), glomerular filtration rate (−60 ± 9 vs. −7 ± 20%), urine flow (−61 ± 7 vs. −24 ± 11%), sodium excretion (−51 ± 15 vs. −32 ± 21%), and fractional excretion of sodium (−50 ± 9 vs. −25 ± 15%) from the denervated kidneys compared with the innervated kidneys during the infusion of norepinephrine. During the infusion of methoxamine there was a significantly greater decrease from the denervated compared with the innervated kidneys in renal blood flow (−54 ± 10 vs. −30 ± 14%), glomerular filtration rate (−51 ± 11 vs. −19 ± 17%), urine flow (−55 ± 10 vs. −39 ± 10%), sodium excretion (−70 ± 9 vs. −59 ± 11%), and fractional excretion of sodium (−53 ± 10 vs. −41 ± 10%). These results suggest that vascular and tubular supersensitivity to norepinephrine in chronically denervated kidneys is due to postsynaptic changes involving α1-adrenergic receptors.

Tubular function

2015 ◽  
Author(s):  
Marijn Speeckaert ◽  
Joris Delanghe
Keyword(s):  
Fractional Excretion ◽  
Tubular Function ◽  
Tubular Dysfunction ◽  
Renal Fanconi Syndrome ◽  
Glomerular Function ◽  
Diminished Capacity ◽  
Fractional Excretion Of Sodium ◽  
Proximal Tubular ◽  
Pass Through ◽  
Renal Tubular

Assessment of tubular function is more complicated than the measurement of glomerular filtration rate. Different functions may be affecting according to the different segments of tubule involved. Key tests include concentrating and diluting capacity, and fractional excretion of sodium. Tubular proteinuria occurs when glomerular function is normal, but when the proximal tubules have a diminished capacity to reabsorb and to catabolize proteins, causing an increased urinary excretion of the low-molecular-mass proteins that normally pass through the glomerulus. Proximal tubular dysfunction is characterized by hypophosphataemia, and a variety of other abnormalities characteristics of the renal Fanconi syndrome. Distinguishing the location of the lesion in Renal Tubular Acidosis is considered in Chapter 35.

Ontogeny of renal response to specific dopamine DA1-receptor stimulation in sheep

1992 ◽  
Vol 263 (4) ◽  
pp. R868-R873 ◽  
Author(s):  
J. L. Segar ◽  
F. G. Smith ◽  
E. N. Guillery ◽  
P. A. Jose ◽  
J. E. Robillard
Keyword(s):  
Sch 23390 ◽  
Plasma Renin ◽  
Fractional Excretion ◽  
Receptor Activation ◽  
Urinary Flow ◽  
Fetal Sheep ◽  
Plasma Aldosterone Concentration ◽  
Arterial Blood ◽  
Fractional Excretion Of Sodium ◽  
Near Term

The present study was designed to characterize the developmental changes in the renal responses to dopamine DA1-receptor activation in chronically instrumented preterm (109-115 days) and near-term (130-140 days, full term 145 days) fetal sheep. Cumulative doses of the selective DA1-agonist fenoldopam increased mean arterial blood pressure (MABP) in both preterm (+16 +/- 3%) and near-term fetuses (+16 +/- 3%) but had no significant effect on renal blood flow velocity. Infusion of the DA1-antagonist SCH-23390 did not affect the increase in MABP, suggesting that the effect of fenoldopam on MABP was not directly related to activation of DA1-receptors. Fenoldopam infusion had no significant effects on renal function parameters in preterm fetuses. In near-term fetuses, however, fenoldopam increased urinary flow rate (82.6 +/- 20.9%, P < 0.003), glomerular filtration rate (GFR; 16.6 +/- 4.9%, P < 0.01), urinary sodium excretion (40.1 +/- 14.9%, P < 0.02), and fractional excretion of sodium (26.8 +/- 11.2%, P < 0.03). Infusion of the DA1-antagonist SCH-23390 blocked the fenoldopam-induced diuresis and natriuresis but had no significant effect on the rise in GFR. Fenoldopam infusion had no significant effects on plasma renin activity and plasma aldosterone concentration and on urinary prostaglandin (PG) excretion (PGE2, PGF2 alpha, and 6-keto-PGF1 alpha). Taken together, these results suggest that the renal effect of DA1-receptor activation is age dependent and that stimulation of DA1-receptor in near-term fetuses is associated with a diuresis and natriuresis that seem to be independent of renal hemodynamics and adrenal effects.

scholarly journals Reversal of Proximal Renal Tubular Dysfunction after Nucleotide Analogue Withdrawal in Chronic Hepatitis B

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Abhasnee Sobhonslidsuk ◽  
Pawin Numthavaj ◽  
Jirachaya Wanichanuwat ◽  
Areepan Sophonsritsuk ◽  
Supanna Petraksa ◽  
...  
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis B ◽  
Chronic Hepatitis B ◽  
Fractional Excretion ◽  
Tubular Dysfunction ◽  
Renal Tubular Dysfunction ◽  
Nucleotide Analogue ◽  
Proximal Renal Tubular Dysfunction ◽  
Renal Tubular ◽  
One Year

Aims. Proximal renal tubular dysfunction (PRTD) is an infrequent complication after nucleotide analogue therapy. We evaluated the outcomes of PRTD and nephrotoxicity after nucleotide analogue withdrawal in chronic hepatitis B (CHB). Methods. A longitudinal follow-up study was performed in patients with PRTD after nucleotide analogue discontinuation. Serum and urine were collected at baseline and every 3 months for one year. The fractional excretion of phosphate (PO4), uric acid (UA), and potassium and tubular maximal reabsorption rate of PO4 to glomerular filtration rate (TmPO4/GFR) were calculated. Renal losses were defined based on the criteria of substance losses. Subclinical PRTD and overt PRTD were diagnosed when 2 and ≥3 criteria were identified. Results. Eight subclinical and eight overt PRTD patients were enrolled. After nucleotide analogue withdrawal, there were overall improvements in GFR, serum PO4, and UA. Renal loss of PO4, UA, protein, and β2-microglobulin reduced over time. At one year, complete reversal of PRTD was seen in 13 patients (81.2%). Improvements in PRTD were seen in all but one patient. Conclusion. One year after nucleotide analogue withdrawal, PRTD was resolved in most patients. Changes in TmPO4/GFR, urinary protein, and β2-microglobulin indicate that urinary biomarkers may represent an early sign of PRTD recovery.

Renal Sodium Handling in Relation to Environmental and Genetic Factors in Untreated Chinese

2020 ◽  
Author(s):  
Yuan-Yuan Kang ◽  
Yi-Bang Cheng ◽  
Qian-Hui Guo ◽  
Chang-Sheng Sheng ◽  
Qi-Fang Huang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Multiple Testing ◽  
Genetic Factors ◽  
Blood Pressure Monitoring ◽  
Lithium Concentration ◽  
Tubular Dysfunction ◽  
Renal Tubular Dysfunction ◽  
Renal Sodium Handling ◽  
Renal Tubular ◽  
Sodium Handling

Abstract Background We investigated proximal and distal renal tubular sodium handling, as assessed by fractional excretion of lithium (FELi) and fractional distal reabsorption rate of sodium (FDRNa), in relation to environmental and genetic factors in untreated patients. Methods Our study participants were suspected hypertensive patients being off antihypertensive medication for ≥2 weeks and referred for 24-hour ambulatory blood pressure monitoring. We collected serum and 24-hour urine for measurement of sodium, creatinine and lithium concentration, and calculated FELi and FDRNa. We genotyped 19 SNPs associated with renal sodium handling or blood pressure using the ABI SNapShot method. Results The 1409 participants (664 men, 47.1%) had a mean (±SD) age of 51.0±10.5 years. After adjustment for host factors, both FELi and FDRNa were significantly (P≤0.01) associated with season and humidity, explaining ~1.3% and ~3.5% of the variance, respectively. FELi was highest in autumn and lowest in summer and intermediate in spring and winter (P=0.007). FDRNa was also highest in autumn but lowest in winter and intermediate in spring and summer (P&lt;0.001). Neither FELi nor FDRNa was associated with outdoor temperature or atmospheric pressure (P≥0.13). After adjustment for host and environmental factors and Bonferroni multiple testing, among the 19 studied genetic variants, only rs12513375 was significantly associated with FELi and FDRNa (P≤0.004) and explained about 1.7% of the variance. Conclusions Renal sodium handling as measured by endogenous lithium clearance was sensitive to major environmental and genetic factors. Our finding is towards the use of these indexes for the definition of renal tubular dysfunction.

scholarly journals Tenofovir disoproxil fumarate-associated renal tubular dysfunction

AIDS ◽  
2017 ◽  
Vol 31 (9) ◽  
pp. 1297-1301 ◽  
Author(s):  
Ryan Samuels ◽  
Carla Roca Bayerri ◽  
John A. Sayer ◽  
D. Ashley Price ◽  
Brendan A.I. Payne
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Tubular Dysfunction ◽  
Renal Tubular Dysfunction ◽  
Renal Tubular

Proximal Renal Tubular Dysfunction Related to Antiretroviral Therapy Among HIV-Infected Patients in an HIV Clinic in Mexico

2015 ◽  
Vol 29 (4) ◽  
pp. 181-185 ◽  
Author(s):  
Karen Andrade-Fuentes ◽  
José A. Mata-Marín ◽  
José I. López-De León ◽  
Bulmaro Manjarrez-Téllez ◽  
Jorge L. Sandoval Ramírez ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Tubular Dysfunction ◽  
Renal Tubular Dysfunction ◽  
Proximal Renal Tubular Dysfunction ◽  
Renal Tubular
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