Dilution Capacity Research Articles

Renal function during hydropenia and water diuresis in children with recurrent urinary tract infections.

SUMMARYThe glomerular filtration rate (GFR), urinary concentrating and diluting capacity and sodium excretion have been determined in 17 children with previous histories of urinary tract infection confirmed by urine cultures. There were no signs or symptoms of infection at the time of the study. Renal function was found to be normal in patients with normal intravenous pyelographies (IVPs). In the patients with renal parenchymal changes a wide variety of functional changes could be found. Reduction of the glomerular filtration rate was the predominant lesion. The GFR could however not be predicted by the IVP‐appearance. Most of the patients were able to increase the GFR during water diuresis. The glomerular‐tubular balance for sodium was reset in 3 of the patients as manifested by an increased CNa/CIn. The concentrating capacity was also reduced in those 3 patients, indicating an impairment of the sodium reabsorption in the loop of Henle. All the patients were able to dilute the urine normally during water diuresis, but 5 of the patients were unable to increase their diluting capacity during the transition from hydropenia to water diuresis. It is noteworthy that only those patients were unable to increase the GFR significantly during the transition from hydropenia to water diuresis.

The Activity Coefficients of Hydrofluoric Acid in Water from 0 to 35 °C.

The mean stoichiometric activity coefficients of hydrofluoric acid in aqueous solutions have been calculated from measurements of electrolytic conductivity, the electromotive forces of galvanic cells without liquid junction, and the freezing-point depression. Values obtained from freezing-point depressions were converted to values for 25 °C using known values of the heats of dilution and apparent molal heat capacities of aqueous solutions of hydrofluoric acid of various concentrations. It is also shown that values for the concentrations of the various ionic species in hydrofluoric acid, namely, H+, F-, , and HF depend on the functions used to represent the ionic activity coefficients whereas values of the mean activity, , are independent of such functions. Values of the pH of various concentrations of hydrofluoric acid are given for temperatures of 0 to 35 °C; these, likewise, are nearly independent of activity-coefficient function used to obtain values for the ionic concentrations.

Effect of hypotonic mannitol and saline load on diluting capacity in man.

AbstractThe effect of hypotonic mannitol and saline loading on the urinary diluting capacity in man has been examined. The further interpretation of the data was built on the assumption that the free water formation is determined by distal tubular Na+ reabsorption. Thus it could be demonstrated that the distal tubular Na+ reabsorption was at first enhanced and later suppressed by progressive increases in the total distal tubular Na+ delivery. No relationship could be demonstrated between distal tubular Na+ reabsorption and urinary Na+ concentration. This was interpreted to mean that the distal tubular Na+ reabsorption was independent of the transtubular Na+ gradient.

Renal diluting capacity in the hypokalemic rat.

Renal diluting capacity in the hypokalemic rat.

Renal amyloidosis presenting as water losing syndrome. Report of 2 cases with biopsy studies.

In two patients with polyuria and polydipsia, renal biopsy revealed amyloidosis. Renal function studies showed specific disturbance of water conservation, with relatively intact diluting, acidifying and ammonium excreting capacity. In addition, the second patient had a nephrotic episode which completely disappeared within some months. It is suggested that the observed abnormalities result from selective impairment of water back-diffusion from the collecting ducts, in the presence of a relatively intact glomerular filtration.

On the nature of the renal concentrating defect in malnutrition

The concentrating and diluting ability of the kidney was studied in adult patients with protein malnutrition before and after protein repletion. During malnutrition, values for maximal urine osmolality and solute-free water reabsorption (T cH 2O) were diminished. Renal diluting capacity, measured by minimal urine osmolality and free-water clearance (C H 2O ), was normal. The renal response to the administration of exogenous antidiuretic hormone (ADH) was adequate, as was the response to nicotine and hypertonic saline solution. During protein repletion there was an improvement in maximal urine osmolality and T cH 2O values. The improvement in concentrating ability occurred pari passu with an increase in urinary nitrogen excretion. The oral administration of urea to four malnourished patients resulted in changes in maximal urine osmolality and T cH 2O similar to those observed with protein repletion. A classification of renal concentrating defects is presented and the mechanism of the renal concentrating defect in malnutrition is discussed within the framework of this classification. The primary role of decreased urea concentration in the renal medulla as the cause of the concentrating defect in malnutrition is emphasized.

STUDIES OF EXPERIMENTAL RENAL FAILURE IN DOGS. I. EFFECT OF 5-6 NEPHRECTOMY ON CONCENTRATING AND DILUTING CAPACITY OF RESIDUAL NEPHRONS.

STUDIES OF EXPERIMENTAL RENAL FAILURE IN DOGS. I. EFFECT OF 5-6 NEPHRECTOMY ON CONCENTRATING AND DILUTING CAPACITY OF RESIDUAL NEPHRONS.

CLINICAL OBSERVATION OF DIABETES INSIPIDUS (Ist REPORT)

Water and electrolyte metabolism was studied in 25 cases with diabetes insipidus, and the following results were obtained:(1) Daily urinary volume in most of the cases (88%) did not exceed eight liters.(2) In the dilution and concentration test, their dilution capacity was not impaired, however, the urinary output per unit of hour was rather uniform, which was indicative of primary polyuria. On the contrary, there were variable degrees of severe impairment of their concentrating capacity.(3) Renal blood flow (RBF), renal plasma flow (RPF), glomerular filtration rate (GFR) and filtration fraction (FF) were not significantly different from those of normal subjects, whereas tubular reabsorption rate (TRR) was materially reduced (10 cases).(4) There was somewhat increased excretion rate of PSP (5 cases).(5) Serum antidiuretic substance (ADS) was at the lower range of that of normal in 6 out of 7 cases. There was also no daily or diurnal variation of ADS, and no decrease was observed following the water load by mouth.(6) By intravenous infusion of hypertonic saline solution, there was a slight decrease in urinary output in one of 4 cases, whereas there was a slight or moderate increase in urinary output in the rest of the cases without elevation of urinary and plasma chloride concentration ratio.(7) By intravenous administration of 0.8 to 2.0mg of nicotine, there was a slight decrease in urinary output in one of 3 cases, whereas no decrease in the rest of the cases.(8) There was no demonstrable change in serum electrolyte concentration (11 cases); there was, however, a marked increase in K/Ca as a result of increased serum potassium concentration following posterior pituitary transplantation.(9) Daily urinary output significantly decreased after posterior pituiatry transplantation, which was accompanied by increase in serum ADS, abolition of urinary dilution capacity and prolongation of time required for disappearance of the elevation produced by intradermally injected salt solution by method of McClure and Aldrich (2 cases). A slight decrease in RPF with increase in GFR, resulting in increase of FF, and elevation of TRR were observed following the transplantation (1 case).

Heats of Dilution and Heat Capacities of Aqueous Solutions of Mono-, Di- and Trimethylamine Hydrochlorides1

Heats of Dilution and Heat Capacities of Aqueous Solutions of Mono-, Di- and Trimethylamine Hydrochlorides¹