Renal Physiology: Impact of Recent Developments on Clinical Nephrology

Spitzer, Adrian

doi:10.1016/s0031-3955(16)32557-3

Cited by 7 publications

(2 citation statements)

References 89 publications

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“…However, we cannot exclude that part of PRC in cord plasma derives from the uterus or intrauterine structures rich in renin (Skinner, Lumbers & Symonds, 1968). The high PRC in the neonatal period might be caused by the immaturity of the kidney with a relatively larger perfusion of the juxtamedullary portion than of the outer cortex (Jose,Logan,Slotkoff,Lilienfield,Calcagno & Eisner,197l), the glomerular-tubular imbalance characterized by relative glomerular preponderance (Edelmann & Spitzer, 1971 ;Spitzer, 1971), and a possibly augmented sodium load to the macula densa (Kotchen et af., 1972), the loss of extracellular volume (Friis-Hansen, 19561, and an increased activity of the sympathetic nervous system. In addition, a diminished elimination of renin from the circulation by the immaturity of liver and kidney may contribute to the augmentation of PRC.…”

Section: Discussionmentioning

confidence: 99%

Age-Dependent Changes of Plasma Renin Concentration in Humans

et al. 1973

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S U M M A R Y1. Plasma renin concentration (PRC) in newborns greatly exceeded PRC in children and adults. PRC in cord plasma of newborns was higher than peripheral venous PRC in their mothers. PRC in the newborns increased further in the first 48 h post partum and then gradually decreased.2. The mean PRC of healthy children and adults on free sodium intake decreased with age by an exponential function.3. The absolute increase of PRC in response to upright posture (PRCuprighl-PRCr,,,,b,,,) decreased with age. The relative increase of PRC in response to upright posture (PRC,,,,,,, : PRC,,,,,,,,,) remained unchanged with age, the PRC in upright posture being about twice the basal PRC in all age groups.Key words: age-dependent renin, renin in childhood, plasma renin concentration. Z U S A M M E N F A S S U N G1. Die Plasma Renin Konzentration (PRC) war in der Neonatalperiode hoher als in der Kindheit und im Erwachsenenalter. Im Nabelschnurblut Neugeborener fand sich eine hohere PRC als im peripher-venosen Blut ihrer Mutter. Die PRC der Neugeborenen stieg innerhalb der ersten 48 Stunden post parrum weiter an und fie1 dann allmahlich ab. 2. Dzr altersabhangige Abfall der PRC gesunder Kinder und Erwachsener wahrend freier Nahrungsaufnahme folgte einer Exponentialfunktion. 3. Der absolute Anstieg der PRC nach aktiver Orthostase (PRCo,lhoslase -PRCRuhe) verminderte sich mit zunehmendem Alter. Der relative Anstieg (PRCorlhoslase : PRCR,,,) war unabhangig vom Alter; die PRC nach Orthostase betrug etwa das Doppelte des Ruhewertes in allen Altersgruppen. 213s 274s K. Hayduk et al.Numerous studies have been done on plasma renin concentration and plasma renin activity in adults in various physiopathological conditions, but there are only a few data in the literature concerning these parameters in the neonatal period and in childhood (

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Section: Discussionmentioning

confidence: 99%

Age-Dependent Changes of Plasma Renin Concentration in Humans

et al. 1973

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“…Infants exhibited lower plasma creatinine concentrations than children when compared with corresponding 51Cr-EDTA-clearances. The values were mostly below the regression line obtained from children, reflecting the physiological finding that plasma creatinine levels are lower in infants than in older children ( 5 , 8), and the low plasma creatinine concentrations of infants are normally associated with a relatively low glomerular filtration rate (6, 17,22). This is most likely due to the lower muscle mass of infants (14, 23).…”

Section: Discussionmentioning

confidence: 92%

ADAPTATION OF A SINGLE INJECTION CLEARANCE METHOD TO PHYSIOLOGICAL AND PATHOPHYSIOLOGICAL FACTS A Review of Data Obtained in Infancy and Childhood

et al. 1977

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A retrospective analysis of 395 51Chromiumethylenediaminotetraacetate single injection clearances performed in infants and children is presented. In 61% of infants and 30% of the children the clearance values were calculated on the basis of a plasma disappearance half time of the reference substance, which was longer than the standard study, i.e. on the basis of extrapolated data. Plasma creatinine and urea levels were found to be appropriate indicators for predicting the plasma disappearance half time of the marker substance. 14 additional patients were studied prospectively with a duration of the study predicted by means of the plasma creatinine and urea levels. In these patients, separate determinations of the clearances using either the data obtained during the standard time of procedure only, or the data of the entire study, clearly demonstrated that the clearances obtained by means of the standard procedure overestimated glomerular filtration rate. The analysis of the data in infants show that the plasma urea level is a reasonably good indicator for predicting the time schedule of the study whereas plasma creatinine should not be used. Additionally the retrospective data indicate that a prolongation of the study should be recommended in all infants. This study demonstrates the necessity and offers means of adapting the time schedule of isotope single injection clearances to physiological and pathophysiological facts.

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