THE NOWASPIRATION OF AMNIOTIC FLUID BY THE CONCEPTUS. RESPONSE OF THE DEVELOPING KIDNEY TO RENAL PARENCHYMAL LOSS. Lily Yuan, Anita Perricelli and David Gitlin. Children's Lorenzo C. Aschinberg, Olli Koskimies, Jay Bernstein, Martin Hospital of Pittsburgh. A. Idash, Chester M. Edelmann. Jr.. and Adrian S~itzer,Albert At first doubted, then attributed to abnormal stimulation Einstein College of Medicine, Bronx, N.Y. and finally only recently confirmed, fetal breathing movements It has been suggested that mrphologic and functional adap- apparently do occur normally in utero. There is general tations to renal parenchymal loss are partially dependent on agreement, however, that these movements are not expansive the intrinsic capacity for growth. This implies that maximal enough to clear the respiratory dead space. In the present changes should be observed in the kidney of the newborn, par- study. 125~-labeledhuman albumin. "~r-labeled rabbit ticularly in the superficial cortex which has the greatest erythrocytes and 85~r-labeledpolystyrene microspheres 15 mu growth potential. Seven mongrel puppies underwent a 75% reduc- in diameter were injected either singly or in combination into tion in renal mass during the first 48 hrs. of life. Four sham the amniotic fluid of rabbit fetuses near term. The operated l i ttermates served as controls. Al l puppies were injections were done via hysterotomy incisions under xylocaine studied 6 wks. later. Renal mass increased by at least 10-fold spinal anesthesia. Three to 24 hours later, the fetuses were in the experimental animals (E) and by 5-fold in controls (C). delivered by hysterotokotomy. All fetal organs were assayed GFR/g of kidney was .71 f .07 (SE) ml/min in E and .55 f . I3 for radioactivity, and where appropriate, sectioned for light in C. As a consequence of hypertrophy and functional ada ta microscopy. Each of the labeled materials was found regularly tion, E animals achieved a mean GFR of 79.8 f 8 ml/min/m 9 BSA- in the fetal lungs and gastrointestinal tract, the which was not statistically different from 92.1 f 13 observed microspheres being visualized in alveolar ducts and alveoli in C. CpAH was 129 f 18 ml/min/m2 BSA in E and 130 + 26 in C. and in the intestinal lumen. Radiolabeled albumin injected Measurements of intrarenal distribution of blood flow (IDBF) into the amniotic fluid of 3 human conceptuses at 13 to 15 with 85~rlabeled microspheres disclosed a significantly lower weeks of gestation was also found in fetal lungs and gastro- percent of flow going to the superficial cortex of the E (43%) intestinal tract when delivered by therapeutic hysterotokotomy than of the C (66%). It appears, therefore, that newborn ani- 5 hours later. Interestingly, the human fetus at 3 to 4 mals achieve a degree of renal functional compensation (-90%) months of gestation swallows approximately half of the which exceeds by far that observed by others in adult animals amniotic fluid volume per day. The data suggest a normal (-50%). The difference in IDBF between E and C is probably penetration of amniotic fluid into the pulmonary passages as the consequence of a disproportional ly higher increase in the far as the alveolar ducts and alveoli. tubular mass of the rapidly growing nephrons. NEPHROLOGY GLOMERULAR SIALIC ACID IN PROTEIN OVERL9AD PROTELNURIA ---Edward B. Blau and ---Rebecca L. Felt, Univ. of Pittsburgh School of Med., Children's How. of Pittsburgh, Dept. of Ped., BODY COMPOSITTON IN mICRATS. Raymond D. Adelman, Jean Harrah and Malcolm A. Hollida , Dept. of Ped., Univ. of Pittsburgh EiEmia, Davis and San Fr&cisco. Sialic acid on the foot processes of the glomerular epithe- Body composition has been studied in uremia to assess lial cell may be essential to maintain the gel filtration pro- state of nutrition and hydration. Hawever, compositional perties of the gl~nerularcapillary filter. A decrease in glo- data, chiefly gathered by measurement of fluid canpartments, rnerular sialic acid has been found in rats with experimental has not been collated with actual organ weights. This was nephrotic syndrome and in children with nephrotic syndrcrme. studied in young, growing male Sprague-Dawley rats made Protein overload with heterologous albumin induces a degree uranic (average BUN 100mg%) by partial nephr%2omy. Extra- of proteinuria similar to that found in aminonucleoside neph- cellular fluid volm (ECV), determined by Br and total msis but without the generalized epithelial cell foot pro- body water (TBW), determined by H30, were measured and cess fusion found in aminonucleoside nephrosis. If the pro- animals sacrificed for renaral of adrenals, brains, hearts, teinuria induced by heterologous albumin overload was not kidneys, livers, and right paravertebral muscles. Uremic associated with a significant decrease in glomerular sialic rats weighed less than control rats (279gm vs 311gm*). ECF acid, it could be more safely assumed that the decreased con- and heart size were relatively greater in uremic animals centration of glomerular sialic acid found in experimental and (25.2% vs 22.6%**; 0.0816~0.0687gm**+), probably indicating human nephrosis was a primarg cause of proteinuria. Protein- an effect on the cardiovascular systen of uremia even when uria greater than the range of control rats (25) was induced mderate. Absolute intracellular fluid volune (TBW-ECV) in 45 of 54, 100g, male rats by 4, daily intraperitoneal in- (133cc vs 144cc), liver (2.98~vs 3.60gnF), mscle mass as jections of 750 mg of bovine serum albumin. Glomerular sialic reflected by 24 hr urine creatinine (8.26ngm vs 9.7bgm *), acid was determined histochemically by the colloidal iron re- and total body solids (82.Sgm vs 104.lgm**) were reduced in action. The intensity of the glomerular colloidal iron stain urenic rats either more than, or in proportion to, reduction in coded slides did not differ between control rats and the in body weight. Absolute brain size was equal. experimental, suggesting that proteinuria alone does not cause a decrease in glomerular sialic acid and that the de- *P<.OS **P<.Ol tdry organ weights reported creases in glomedar sialic acid previously reported are sig- nificant in the pathogenesis of proteinuria. SALT WASTING NEPHROPATHY OR "PSEUDOHYPOALDOSTERONISM" IN THE UTILITY OF SINGLE INJECTION CLEARANCES OF CHEMICAL INULIN AND PAH IN CHILDREN WITH OBSTRUrnIVE UROPATHY. Frank G. Boineau, Brigitta Peterson, Alfred Scherzer, and John E.Lewy. Cornell Univ. Med. Co1.-N.Y. Hosp., Dept. of Ped., New York. thrive, hyponatremic dehydration, and hyperkalemia. Renal Children with obstructive uropathy present difficult prob- function and glucocorticoid production were normal. Routine lems in the measurement of renal function due to their reten- fluid and electrolyte replacement failed to correct the dehy- tion of urine within the urinary tract. The single injection dration, and the administration of desoxycorticosterone gave no (SI) of isotopically labelled markers for the estimation of response. Urinary aldosterone levels were consistently elevat- glomerular filtration rate(GFR) and renal plasma flow(RPF)has ed, and urinary excretion of sodium was disproportionately been shown to be accurate when compared with constant infusion high. The patients responded to a daily supplementary intake (CI) methods. The use of chemical inulin and PAH offers the of 3 g of sodium chloride, with correction of the hyponatremia further advantage of avoiding the injection of radioisotopes and dehydration and return of serum potassium concentrations to in children. We have compared CI and S1 clearances using normal. Salt supplementation was discontinued after 15 months. chemical inulin and PAH in eight children aged 4-11 yrs.,with The twins continued to thrive on regular diet and maintained obstructive uropathy due to meningomyelocele. All had neuro- normal levels of serum sodium and potassium, yet their urinary genic bladders with poor emptying or ileal conduits but normal and plasma aldosterone levels remained high. The observations upper tracts on IVP. Urine was collected during CI clearance suggest that the defect (1) may be familial and genetic, (2) periods by an indwelling catheter in the patient's bladder may be caused by failure of the renal tubules to respond to or ileal conduit. aldosterone, and (3) is correctable by increased intake of Inulin clearance was 128. t 8.5 (SEM) when estimated by SI sodium chloride. and 129.4+13.3 ml/min/.1.73 M 4 when estimated by CI (~0.809). PAH clearance was 615.0t74.6 by SI and 506.4+59.7 ml/min/1.73 M~ when estimated by CI (~0.920). The SI of chemical inulin is thus comparable to CI of inulin as a method for estimating GFR in patients with obstructive uropathy. PAH clearances on the other hand were consistently higher when measured by SI than by CI techniques and did not provide a comparable estimate of RPF. .