Renal Failure

Platt, Robert W.

doi:10.1016/s0140-6736(51)92751-1

Cited by 19 publications

(6 citation statements)

References 5 publications

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“…22 and 39, however, the filtration rate was above 60 cc. per min., and these two subjects, if not subject 9 Figure 3 shows the relationship between specific gravity and osmotic U/P ratio in the same urine samples, with selection of those samples showing the maximal specific gravity. The gross lack of correlation in Figure 3 is obvious.…”

Section: Resultsmentioning

confidence: 99%

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The Elaboration of Osmotically Concentrated Urine in Renal Disease

Baldwin¹,

Berman²,

Heinemann³

et al. 1955

J. Clin. Invest.

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During the hydropenic state, the kidney, in the interest of water conservation, excretes a urine which is osmotically more concentrated than the blood. Since the glomerular filtrate has the same osmotic pressure as the plasma, in the elaboration of an osmotically concentrated urine the renal tubules must remove from this isosmotic filtrate a certain quantity of solute free water. The quantity of water so removed from any sample of urine is given by the difference between the volume of urine required to contain the urinary solutes in an isosmotic state, or the osmolar clearance, Co.m, and the urine-flow, V(1).

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Section: Resultsmentioning

confidence: 99%

“…(9). Insofar as there is substantial splay at the intermediate urine flows where-we pass from the patameter of.…”

Section: Discussionmentioning

confidence: 95%

The Elaboration of Osmotically Concentrated Urine in Renal Disease

Baldwin¹,

Berman²,

Heinemann³

et al. 1955

J. Clin. Invest.

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“…Reports by other workers on the influence of filtration on urinary concentration allow some prediction as to' the effect of this function in the present study. Platt (23) has pointed out the importance of considering the osmolarity-flow relationship in terms of nephron flow. When a large fraction of the renal tissue is removed in the experimental animal, renal concentrating ability is reduced although'the nephrons remaining are presumably not injured.…”

Section: Discussionmentioning

confidence: 99%

A Comparison of the Relative Effectiveness of Hydropenia and of Pitressin® in Producing a Concentrated Urine12

West¹,

Traeger²,

Kaplan³

1955

J. Clin. Invest.

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It is a common assumption that exogenous antidiuretic hormone (Pitressing) is equal to the endogenous anti-diuretic hormone (ADH) in its ability to stimulate the production of a concentrated urine. However, clinical studies of urine formation after the administration of Pitressin'S or Pituitrin@ leave some doubt as to the ability of the exogenous hormone to produce a maximally concentrated urine. Sodeman and Engelhardt (1) found that if urinary specific gravity was low at the time of Pituitrin0 administration, the value attained was not so high as could be produced in the same subject by water deprivation. Similar observations were made by Little, Wallace, Whatley, and Anderson (2). Taylor, Peirce, and Page (3) gave Pituitrin@ at frequent intervals for 12 hours and found the urine to be often more dilute and of larger volume than after a 12-hour period of water deprivation. In every case the amounts of anti-diuretic hormone administered were much greater than are assumed to be normally produced.In the present study the ability of exogenous anti-diuretic hormone, administered as Pitressin@, to concentrate the urine has been reinvestigated in humans and in the dog. Because it is now recognized that the concentration of urine depends not only on the degree of hydropenia, but also on the prevailing rate of solute excretion (4-6), it seemed pertinent to investigate urinary concen- tration after Pitressin® administration during mild solute diuresis as well as under normal conditions of urine formation. To insure absence of circulating endogenous anti-diuretic hormone at the time PitressinD was tested, the subjects were hydrated and having a water diuresis at the start of hormone infusion. In evaluating the results, the urinary concentrations after Pitressins, expressed in milliosmols, have been compared with the urine osmolarity of hydropenic subjects, taking into account the fall in osmolarity normally occurring during solute diuresis.It was found that once water diuresis was inhibited by the administration of PitressinS, urine osmolarity slowly increased to approach, but rarely equal, values observed during hydropenia. Differences in plasma osmolarity in the hydratedPitressin(D and hydropenic groups accounted to some extent for the discrepancy. When urine osmolarity was expressed as a function of plasma osmolarity, either as the osmotic U/P ratio or the urine-plasma osmotic pressure difference, values after a sufficient period of Pitressin@ infusion were often comparable to those of hydropenic subjects providing solute diuresis was present. In the absence of solute diuresis, the results were not as consistent. Prolonged Pitressin® administration in several instances failed to elevate osmotic pressure differentials to values observed in hydropenic subjects. METHODSFor the study 32 experiments were performed, 17 on eight female mongrel dogs and 15 on five male subjects. At least two experiments were usually performed on each subject, one to determine urinary concentration during hydropenia and a second to test the eff...

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“…Zusammenfassung: An 20 Ratten mit experimenteller bilateraler Pyelonephritis wurden Mikropunktionsexperimente durchgefHhrt. In sp~tproximalen, frHh-und spgtdistalen Nephronabschnitten wurden Proben von TubulusflHssigkeit entnommen und in ihnen die Konzentrationen von Inulin und Harnstoff bestimmt.…”

Section: Abstract: Experimental Pyelonephritis -Concentrating Defectunclassified

“…It has been postulated that the resulting increased flow of solute and water in the surviving nephrongs may account for the concentrating defect in chronic renal disease (19,20). A considerable number of investigations, however, have suggested that the concentrating defect may be more severe than expected from the decrease in nephron units (I, 5, 6, 8, 9, ]4), and it has been suggested that some intrinsic impairment in renal medullary function might contribute to the loss of concentrating ability.…”

Section: Abstract: Experimental Pyelonephritis -Concentrating Defectmentioning

confidence: 99%

Single nephron study of intrarenal urea handling in experimental pyelonephritis

et al. 1975

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Micropuncture experiments were carried out in 20 rats with bilat. experimental chronic pyelonephritis. Inulin and urea concentrations were estimated in the late proximal, early distal and latte distal nephron segment. Proximal urea reabsorption did not differ from that in control animals. Fractional amount of filtered urea in the early distal segment was significantly lower in the pyelonephritic rats, urea reabsorption in the distal tubule approcimated zero. The data indicate that intrarenal urea recirculation is abolished by the experimental lesion, thus determining maximal urine urea concentration. It is suggested that the concentrating defect of experimental pyelonephritis is not only a result of an adaptational increase in individual nephron GFR; an additional intrinsic lesion seems to be present, located in the renal medulla.

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Renal Failure

Cited by 19 publications

References 5 publications

The Elaboration of Osmotically Concentrated Urine in Renal Disease

The Elaboration of Osmotically Concentrated Urine in Renal Disease

A Comparison of the Relative Effectiveness of Hydropenia and of Pitressin® in Producing a Concentrated Urine12

Single nephron study of intrarenal urea handling in experimental pyelonephritis

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