STUDIES ON HUMAN PROTEINURIA

(1)

STUDIES ON HUMAN

PROTEINURIA

I. The Mechanism of PosturalProteinuria

R. J. Slater, M.D., N. J. O'Doherty, M.D. (N.U.l.), M.R.C.P., and M. S. DeWolfe, MA. Research institute of The Hospital for Sick Children, and the Department of

Paediatrics, Faculty of Medicine, University of Toronto T HE SITE of formation of postural pro

teinuria has never been clearly defined, although it is generally assumed that the urinary proteins arise by glomerular filtra tion from plasma. This assumption has been challenged by Lowgren1 who considers postural proteinuria to be an excretion of renal lymph arising from the fornix of the calyces in the renal pelvis, a location con siderably distal to the tubules.

Subjects who exhibit postural proteinuria excrete normal urine while they are recum bent, but when they assume the erect pos ture, especially with lordosis, proteinuria will be found in the next urine voided. This frequently persists in diminishing amount during the following20 to 40 minutes, even

though the recumbent position has been

resumed. There are at least two explana

tions which might account for these find ings. It may be that alteration in renal func tion permitting proteinuria operates as a sharply defined circumstance, e.g., during erect posture, and this dysfunction may rapidly reverse upon recumbency. In this case, the diminishing proteinuria would de rive from that contained in the â€œ¿dead spaceâ€•of the urinary collecting system after the bladder had been emptied. On the other hand, the phenomenon might be ex

plained on the basis of a less quickly re versed change in renal dynamics resulting in decreasing protein leakage for a period after the subject returned to recumbency.

In the course of studies on the mecha nism of different types of proteinuria,2 which include observations on 15 children

with postural proteinuria, a simple investi gation was carried out which elucidates in part the origin of the urinary proteins caused by orthostasis. Furthermore, by comparison with other â€œ¿normalâ€•types of proteinuria (exercise, and the daily minute excretion of protein), certain differences were found which emphasize the present lack of understanding about the renal han dling of proteins.

SUBJECTS

Four boys and one girl with postural pro teinuria which had been discovered coinci dentally were observed during sequential short periods of alternating orthostasis and recum bency. Urines were voided spontaneously. Al bumin labelling was achieved by intravenous injection of 3.0 to 5.0 ml of the dye T-1824 in all patients, and Ilh1@labelled human serum al bumina into two patients. The quantity of dye was estimated to produce an approximate color in the serum of O.D. = 1.0.

METHODS

The concentration of urinary proteins was determined by biuret analysis@ or by a quan titative precipitin technique.@ The time of ap pearance in the urine of dye T-1824 was esti mated by visual scanning of urine samples from above through the length of the test tube. Recognition of the blue color was more readily obtainedby thisprocedure than reading in a colorimeter at 620 m@ because of interference from other urinarychromogens absorbing at this wavelength. The concentrationof I131@

0 Radio-iodinated hu.man serum albumin Charles Frosst Co., Montreal, P.Q.

Supported by grants from The National Research Council of Canada, and the Department of National Health and Welfare.

Dr. Slater was a Playtex Park Research Institute Grantee.

ADDRESS:(R.J.S.) Hospital for Sick Children, 555 University Avenue, Toronto 5, Ontario, Canada.

PEDIATRICS, August 1960

(2)

ARTICLES 191

tural proteinuria appeared rapidly (Table I). At the conclusion of Period 3, a time when proteinuria was rapidly decreasing, 3 ml of the dye T-1824 was injected intra venously. Extreme lordosis was immediately initiated. Following the injection, the boy developed a feeling of faintness, conse quently only 3 minutes of lordosis could be maintained during the 12 minutes of Pe riod 4. Upon resuming lordosis through Period 5, a great increase in the concentra@ tion of urinary protein occurred in associ ation with a distinct blue color (O.D., 0.26). As in Case 1, the blue color was protein

bound dye.The totaltime between dye in

jection and the end of period 5 was 21 minutes. Thus lordosis was associated with

a rapidtransferof dyed proteinfrom blood

to urine.

CASE 3: L.S. was studied after quiet ac tivity. Upon emptying her bladder, which revealed a trace of urinary protein, lordosis was initiated and 5.0 ml of T-1824 was in jected intravenously. Urine voided 2 min utes after injection contained a trace of pro tein but no blue coloration. However the urine of a second voiding, 3 minutes later, was a distinct blue color. Thus labelled pro tein appeared in the urine 5 minutes after

injection of dye.

CASE 4: R.P. received 5.0 ml of T-1824 and 12 p.c of I'31-labelled human serum albumin at the end of Period 1, immedi ately before commencing lordosis. Table I reveals that this boy had a marked decrease in urine excretion during lordosis. Periods 2 and 3 were productive of only 0.90 ml and 0.56 ml of urine, respectively. The urine of Period 2 appeared dilute and was essen tially colorless, similar to the prelordotic urine of period 1. In contrast, the urine of Period 3 appeared markedly concentrated and yellow in color. Previous experience has indicated that a high concentration of

normal chromogens may mask small

amounts of the blue T-1824 and this may account for the failure to observe any blue color. Period 4, which ended 29 minutes after injection of the dye resulted in 1.0 ml of blue-colored urine.

labelled albumin was defined by counting the

twice-washed precipitate of 0.3 to 1.0 ml of urine in a deep-well scintillation detector.

Electrophoretic analyses of serum and uri nary proteins were made on paper using Ver onal buffer at pH 8.6, P12 = 0. P. Urinary proteins were concentrated prior to study to

approximately 7 to 8 gm/100 ml in Visking

cellulose bags immersed in 25% polyvinylpyrro lidone.

The @-globulinscontained in different types of proteinuria were compared by the quanti

tative precipitin technique.@ Using rabbit anti serum to purified normal @-globulin of serum, the precipitation curve was developed through the region of antibody excess to equivalence.

The height of the curve reflected the relative precipitating characteristics of the particular

@-globulin.

RESULTS

Time of Excretion of Labelled Protein

CASE 1: C.A. was observed during two periods of lordosis. Table I indicates that during the activity of travelling to the clinic the boy excreted 0.24 mg of protein/ml.

(PeriodI).Immediatelythereafter,17 min

utes of lordosis increased the urine protein concentration to 5.75 mg/ml. In order to determine if the protein excretion which continued following lordosis represented an â€œ¿activeâ€•transfer from renal capillaries, 3 ml of T-1824 was injected immediately upon

resuming recumbency (end of Period 2).

During the next three periods, the patient

remained recumbent.Despitean increased

concentration of urinary protein to 11.0 mg/ml during Period 3, no blue dye was apparent. Furthermore, no dye was dis cernible during decreasing protein excre tion of Periods 4 and 5, which extended the

totaltime of recumbency to 1 hour.During

Period 7, lordosiswas again initiatedand

proteinuria recurred. Blue urine immedi

ately appeared and became deeper in color as the urinary protein concentration rose to 10 mg/ml during recumbency. It appeared that lordosis was a prerequisite for the dye to appear in the urine.

(3)

. Patient Record No. AgePeriodTime (mm)Urine F/on' (mi/mm)Protein Con ceniration in Urine (mg/mi)tTr@@@ ColorPositionCA. (Case 1) uSC, P.O.P. Male, 8 yearsI

2 3 4 5 6 7 8 9225 17 15.5 14.5 15 16.5 9.5 18 150.560.24 1.06 5.75

inject 3 ml T-1824, i.v.

0.24 11.0 0.36 1.35 0.46 0.30 0.59 0.12 0.68 5.90 0.15 10.00 0.30 0.45Yellow Yellow Yellow Yellow Yellow Yellow Blue Blue BlueActive (trip to clinic) Lordosis Recumbent Recumbent Recumbent Recumbent Lordosis Recumbent RecumbentE.V. (Case 2) HSC #314565.

Male, 8 years.1 2

3 4 5 610 1.5 15 12 9 141

.3 3. So

0.6 1.22

1.4 0.13

inject 3 ml T-1824, iv.

1 .3 0.04

0.13 33.30 0.20 9.90Yellow Yellow Yellow Colorless Blue BlueLor(losis Recumbent Recumbent Lordosis Lordosis RecumbentL.S. (Case 3) uSC #373627.

Female, 11 years.1

22 3inject

5 ml T-1824, i.v.

2.7 4.40

0.7 42.10Yellow BlueLordosis LordosisR.P.

(Case 4) HSC #426723. Male, 14 years.1

2 3 4 5 6 77

inject 5 ml 7 14 8 6 6 139.5 T-1824, i.v., 0.13 0.04 0.12 1.00 1.30 2.300 Colorless & 10 @scPâ€•-albumin

2.7 Colorless 10.50 Yellow 19.00 Blue 14.00 Blue 9.0 Blue 4.6 BlueRecumbent i.ordosis Lordosis Lordosis Recumbent Recumbent Recumbent 192 TABLE I

EXCRETIONS OF PROTEIN IN THE URINE IN RELATION TO PosITION

Concentration of protein in urine is recorded rather than the excretion rate, because the concentration is not

only the criterionby which the amount of radioactive-labelledproteinisbestjudged,but isalsothe basisforre vealing presence or absence of proteinuria. As stated in the text, the urine color is recorded as judged by visual appearance, and varied considerably in intensity.

Analyses of the specific activity of the

radioactively labelled albumin in the urine from Case 4 appears in Table II. Blood sampling was done midway during Period 4, 32 minutes after injection of the labelled albumin. It is apparent that the specific ac tivity of urinary albumin was initially high and thereafter became identical, or closely

(4)

PeriodAlbumin

in Urine (mg/mi)Specific

Activity of Albumin (counts/sec/mg)1

2 3 4 5 6 70

1.28 5.37 7.78 6.00 4.99 2.600

3.6 2.4 2.4 2.0 1.8 2.1Serum33.402.1

ARTICLES 193

blue and radioactivity increased propor tionately with the protein concentration in the urine from Period 5 to Period 6. The protein content of the serum was deter mined by biuret analysis and then diluted 1/7.5 in order to approximate protein con centration of the urine of Period 6. The specific activity of the diluted serum was 59 counts/mm/mg of protein in contrast to the urine value 50 counts/mm/mg of protein. This difference might be accounted for by the variation in apparent concentrations of protein in the serum and urine as defined

by the biuret technique, since this method

on occasion may result in falsely high values for urinary proteins and cannot com pare to the accuracy of the immunologic

estimationsofalbumin performedinCase 4.

These findings again indicated that the rapid appearance of labelled plasma pro tein in the urine may occur and that this transfer evidently occurs only during active

lordosis.

ElectrophoreticPatterns

A further understanding of the nature of postural proteinuria is gained by study of the constituent proteins. Figure 2 illustrates TABLE II

STUDIES OF CASE 4 WITH I'31-LABELLED ALBUMIN

The use of radioactive-labelledalbumin was a much superiortracerthan dye T-1824.Referenceto the data on Case 4 in Table I indicates that while P31-labelled albumin was readilydeterminedduring Periods2 and 3 no bluedye couldbe detected.

transport of the labelled protein in the

small urine volumes from nephron to

bladder could account for the prolongation of high activity values during Periods 3 and 4. Blood sampling was done at a time when intravascular equilibration could be as

sumed, and prior to any significant equili bration into the extravascular protein pool.

These findings indicated that during transfer of labelled protein from plasma to

urine, there did not occur any dilution of labelled protein into an unlabelled pool. Such a result strongly suggests transfer of protein from plasma directly into urine, and not via an intermediary lymphatic pool.

CASE 5: G.H. was also studied with re spect to the renal excretion of both T-1824 and P31-labelled albumin. Figure 1 illus trates the increased proteinuria associated with lordosis in Period 2. Immediately fol lowing cessation of lordosis, 3 ml of T-1824 and 10 p.c of I'3-labelled albumin were in jected intravenously. During the ensuing two periods of recumbency and decreasing proteinuria, lasting a total of 21 minutes, no blue dye could be detected in the urine. Furthermore, protein-bound 1131 remained just above background radiation level. A marked change occurred with resumption of lordosis. The urine became obviously

U

Collection Period

Fic. 1. Case 5. Postural proteinuria. Positions U, L and R indicate upright moderate activity, lordo sis and recumbency. The concentration of protein bound Iâ€• during Periods 3 and 4, following in jection, was considered insignificant in contrast to

(5)

NORMAL

SE&@

PRov'E@N04 @1A

Posru&A@

PROTE,Nag R.A

NEPNROrsc

NEPH *ATIC

NEPPIRoTIc

NOR AL

FIG. 2. Patterns of proteins by paper electrophoresis. The arrow indi

cates origin and direction of migration. Variation in total amounts of protein in the urinary concentrates makes difficult a comparison of the

relative concentration of different components. Nevertheless, some gen

eral similarities as well as differences can be seen in the patterns from patients with nephrosis and postural proteinuria.

1-the patterns of the urinary proteins from two patients as revealed by paper electro phoresis. The similarity of the patterns of postural proteinuria to normal serum stand in marked contrast to the patterns of the

serum and urineproteinsin patientswith

nephrosis.

In the patterns of postural proteinuria,

albumin, 13-globulinand y-globulinconsti

tute the three chief components and are present in proportions similar, but not identical, to normal serum. The urinary or@-and x2-globulin components usually ap pear in lower concentrations than in serum and frequently may fail to be visualized, as in the third pattern from the top in

Figure 2. Despite the similarity between the appearance of the patterns in serum and urine in postural proteinuria, immuno logic estimations reveal that the i-globulin: albumin ratio of the urine is usually slightly lower than that of the serum.2

In contrast to postural proteinuria, the electrophoretic patterns of urinary protein

in the nephroticsyndrome do not reflect

theproportionsofthe serum proteinswhich

are presentedto the glomerulusfor filtra

tion. The characteristics of renal perme ability to plasma macromolecules are quite different from those in postural proteinuria.

Although no i-globulincan be visualizedin

(6)

I Standard

CurveNephrosisPostural Proteinuria IPosturalProteinuria UExerciseProteinuriaâ€˜Normalâ€• Proteinuriaâ€˜1-Globulin

antigenSerum

.â€”.

Urine @â€”¿â€”vSerum .â€”

Urine @Urine @Rugby

?â€”@-@ Wrest(er.â€”@â€”â€˜â€”â€”@@t

I

10 20 30@â€˜

V I

;

I I I @/1

&@

@ \\

/

I I V â€˜¿

Ik

@I

V â€˜¿â€˜ 1 I \ I @ _V I @ I \ T

I

I I I V 1 I I I

0.@5 I l.@I'â€•

# I' \@ â€œ¿ â€œ¿I â€¢¿@V @7 I 7

R d.s I l.@I

,â€˜ I' Iâ€•,. V I g â€˜¿ I I I II I 0.5 1 IST-Globulln @g.AddedSerum X IO@ Urine X I0@Serum

X l0@

Urine X I0@Urine X 10'I

2 3

Urine X I0'. Urine X 10@2 195 ARTICLES 0.6 0.5 >-I (1) Z 0.4 Id 0 @0.3 0 0.2

trated in Figure 2, immunologic estimation revealed each to contain about 5% of the albumin concentration. A prominent uri nary 1@-globulmn is characteristic of the nephrotic syndrome, being composed in the main of transferrin.2 Great variation exists in the amounts of or@-and 22-globulins, as

well as undefined intermediateglobulins

which may appear in the urine of certain

patientswith nephrosis.

ImmunologicReactivityof the

Urinary â€˜¿i-Globulin

Another reflection of the handling of pro teins by the kidney may be gained by com parison of the molecular characteristics of serum and urinary proteins. In the course of studies on the immunochemical identi fication of urinary proteins, comparisons of the i-globulin in different â€œ¿normalâ€•and pathologic proteinurias have been made. By means of the quantitative precipitin

0.1

SERUM and URINE ANTIGEN â€”¿ml. ADDED

FIG. 3. Reactivity with antiserum to serum â€˜¿i-globulin. The height of the precipitin curve is assumed to

reflect the relative similarity of the various â€˜¿i'-globulinsto the native serum antigen. It is not yet clear whether the same factors are responsible for the mild depression in immunologic reactivity (Postural

Proteinuna II) as for the greatly decreased reactivity (Rugby urine).

technique, a comparison of the combining

characteristicsof i-globulinfrom different

urinary proteins with specific rabbit anti body to serum i-globulin may be made.

Figure 3 illustratessome examples of the

precipitin curves through the region of anti body excess, developed by the i-globulin of proteins from patients with postural pro teinuria and with exercise proteinuria com pared to â€œ¿normalâ€•urinary proteins. The latter was a concentrate of 16 litres of urine from healthy individuals. The i-globulin of postural proteinuria usually behaved in a manner similar to the i-globulin of normal serum and to the i-globulin excreted in nephrosis. The i-globulin moiety from ex ercise proteinuria, as well as from normal

urine, appears to react only partially. No

variations in reactivity of this type could be shown for the corresponding urinary al

bumins when studied with albumin anti

(7)

DISCUSSION

Postural proteinuria is almost universally recognized as a benign condition. However, its presence is occasionally interpreted as

evidence of renaldisease.A seriesof ob

servations made during the past 10 years have assisted greatly in delineating the al terations in renal function which cause

orthostaticproteinuria.Bull6 noted that

patients in lordosis who developed pro teinuria had higher pressures in the renal vein than those who failed to develop pro teinuria. The theory that increased venous hydrostatic pressure of lordosis causes pro teinuria was not supported by Farber et al.@These investigators were unable to pro duce proteinuria in the supine position when the venous pressures were elevated by obstruction of the inferior vena cava. Thereafter, Greiner and Henry8 observed that peripheral pooling of blood in the su pine position was associated with protein uria, even in the presence of a decreased renal venous pressure. They proposed that decreased venous return caused central cir culatory inadequacy; this in turn caused re flex splanchnic vasoconstriction.

King and Baldwin9 revealed that intra venous infusion of l-norepinephrine into normal adults and into those with postural proteinuria would invoke proteinuria in most instances. Repetition of this work in five affected children at our hospital has

failed to reproduce these findings,for

reasons which are not yet clear.'Â° In proteinuria of renal disease, Lathem and coworkersfl,12 studied the influence of orthostatic versus norepinephrine-induced vasoconstriction upon protein excretion. Pa tients placed in lordosis had not only a de creased rate of excretion of urinary protein, but also a proportionately greater decrease in water excretion. The resultant relative increase in concentration of urinary pro tein accounted for the â€œ¿posturalprotein uriaâ€•of renal disease. However, similar pa tients receiving an infusion of norepineph rine responded with an increased excretion of urinary protein.

Although renal vasoconstriction appar ently plays an important role in altering renal function relative to the handling of proteins, it is not clear by what mechanism these changes in function occur. The fore going evidence favors decreased renal blood flow.

Against this background, the develop ment of proteinuria could occur at three possible sites:

1) Increased glomerular filtration of pro tein which upon passing down the tubule temporarily overwhelms any protein reab sorptive mechanism.

2) Decreased tubular reabsorption of an approximate 30 mg of protein per 100 ml of glomerular filtrate, which is postulated to be filtered normally by the glomeruli. (By this hypothesis, approximately 32 gm of protein per square meter of body surface are filtered and reabsorbed per day.)

3) Transfer of protein from renal lymph or vasa recta into the collecting tubules or areas adjacent to the sinus renalis.

Pappenheimer'@ considers that renal glomeruli are about threefold more perme able than capillaries elsewhere. Thus an increased permeability of the glomeruli to protein might not necessarily be caused by vasoconstrictive ischemic damage, but might be explained by increased molecular sieving from plasma to glomerular filtrate as the renal blood flow declines.

The concept of postural proteinuria being glomerular in origin has been questioned by Lowgren.' Since the proteins excreted in postural proteinuria and renal lym

phuria (chyliiria)have similarelectropho

(8)

ARTICLES 197

from lymphatic leakage. The renal lymph

presumably would not yet have been suffi

ciently equilibrated with plasma to provide the concentrations of labelled proteins which were found.

Bearing directly upon this interpretation is the lack of knowledge regarding rate of vascular-lymph equilibration within the kid

ney. Lassen et al.14 demonstrated that after

intravenous injection of Ph1,labelled albu min into the dog, very rapid accumulation of labelled albumin occurred in the renal medulla (as rapidly as 3 minutes). This may well be a function of the high concentration of plasma occurring in the vascular bundles

of the renal papillae which are active in the system of counter-current exchange of wa

ter and electrolytes. In addition) LeBrie'5 has found that obstruction of the renal vein

in dogs causes a marked increase in the flow of renal lymph and that the concentra tion of lymph protein may increase to 30â€”50 mg/mi. Such alterations in renal blood lymph dynamics might account for postural

proteinuria. However, studies by Klaus on dogs16 revealed that increased renal venous pressure failed to induce proteinuria de spite exponential increases in lymphatic

flow.In fact,obstructionofrenallymphatics

combined with increased renal venous pres sure likewise caused no proteinuria.

It would seem that the renal pelvis or the area of the collecting tubule could be the site of origin of postural proteinuria in the human only if intravascular-extravascular protein transfer during lordosis occurs at a rate much faster than indicated by the whole-body value (t% = approximately 12 hours17). However, the identical specific activity of the serum and urine albumin in dicates that dilution of serum albumin into an extravascular pool of renal lymph albu min could not have occurred prior to its appearance in the urine. Unless it can be

proved that plasma proteintransfersdi

rectly out of the vasa recta into the urine without intermediate mixing in renal lymph, it must be assumed that postural proteinuria arises from glomerular filtra tion.

A marked similarity in the electropho

retic patterns of proteins from patients with

postural proteinuria exists from one indi vidual to another, and from time to time in

the same individual.2 As noted previously, there is a lower i-globulin:albumin ratio in urinary proteins in postural proteinuria

than in serum. The proportion of the com ponents of urinary protein is very similar to

values derived for lymph and indicates that

some selective permeability in the transfer of the proteins from plasma to urine has oc curred. However, this similarity in the rela tive proportion of components in postural proteinuria and in lymph does not neces sarily indicate that postural proteinuria arises by fortuitous leakage of renal lymph.

It well might be interpreted that this simi

larity in protein patterns indicates the rela tive permeability of the healthy glomerular membrane permitting increased diffusion of different plasma proteins during lordosis.

Thus, glomerular filtrate would be akin to

interstitial lymph. Provided that no prefer ential tubular reabsorption of discrete pro teins occurred during passage of the glom erular filtrate distally, the patterns of uri nary protein would reflect the pattern of the glomerular filtrate. Such considerations must remain conjectural pending further

understandingof the glomerularand tubu

lar handling of the numerous plasma pro teins of different biophysical properties.

The significance of the variation in the patterns of immunologic precipitation re vealed by normal serum i-globulin and the i-globulin from different types of â€œ¿normalâ€• proteinuria is not clear. Webb et al.â€• re ported that the i-globulin present in pro tein in normal urine has a smaller molecu lar weight (10,000) than serum i-globulin (160,000). In addition, by isotope tech nique, Franklin19 revealed that these i-globulin fragments of normal urinary pro tein are derived from the native serum

i-globulin.Whether thistype of alteration

of the i-globulins occurring to an increased

(9)

POSTURAL PROTEINURIA

the present study. In contrast, the i-globu lin of postural proteinuria usu@illy has reac tivity much more similar to that of serum

i-globulin.The mechanism responsiblefor

thevariabledepolymerizationofi-globulins

found in the urine is not known, and

whether itisa pre-renalor renalfunction

remains to be elucidated.

The present study illustrates clearly that

posturalproteinuriarepresentsa rapidly

reversible functional alteration of the kid ney. The failure of labelled albumin to appear in the decreasing proteinuria which continues after lordosis indicated that this proteinuria consisted of proteins previously filtered during lordosis. Thus, the presence of decreasing proteinuria does not repre sent a slow recovery to normal permeability after lordosis, but simply washing out of protein from the higher reaches of the uri nary collecting system.

Whether the proteinuriainduced by or

thostasis originates by glomerular filtration cannot be finally resolved until a better understanding of the transfer rates of pro teins out of vascular bundles of the renal medulla is obtained. In the present study, the rapidity with which the labelled pro teins passed from plasma to urine, and the identical values of specific activity of al bumin in serum and urine, strongly sug gest that this is primarily a function of in creased transfer of plasma proteins through the semipermeable glomerular filtering sur face.

SUMMARY

Observationson the transferof labelled

albumin from plasma into urine were made in five children with postural proteinuria. Transfer of labelled protein occurs rapidly during lordosis. During the period of de creasing proteinuria that occurs upon cessa tion of lordosis, no transfer of labelled pro tein could be observed. These findings suggest that the functional alteration caus ing postural proteinuria is rapidly reversi ble, occurring only during the orthostasis. Despite the similarity in composition of proteins in postural proteinuria and in

lymph, the rates of protein transfer and the similar specific activity of serum and uri nary protein suggest that the site of trans fer is the glomerular capillary.

Immunologic study of the urinary pro teins indicate that the i-globulin excreted in postural proteinuria is similar to that of serum, in contrast to the i-globulin ex creted in exercise proteinuria and â€œ¿normalâ€• urinary protein which reveal altered char acteristics.

Acknowledgment

Grateful appreciation is expressed to Miss Barbara Brown and Mr. Donald Mills for their technical assistance.

REFERENCES

1. LÃ¶wgren, E.: Studies on benign protein

uria. Acta med. scandinav., Suppi. 151,

1955.

2. Slater, R. J.: Unpublished data.

3. Hiller, A., Greif, R. L., and Beckman, W.: Determination of protein in the urine by the biuret method. J. Biol. Chem.,

176:1421, 1948.

4. Slater, R. J., Ward, S. M., and Kunkel, H.: Immunological relationships among the myeloma proteins. J. Exper. Med., 101: 85, 1955.

5. Slater, R. J., and Kunkel, H.: Filter paper electrophoresis with special reference to urinary proteins. J. Lab. & Clin. Med., 4:619, 1953.

6. Bull, G. M.: Postural proteinuria. Clin. Sc., 7:77, 1948.

7. Farber, S. J., Becker, W. H., and Eichna, L. W.: Electrolyte and water excretions and renal hemodynamics during in duced congestion of the superior and inferior vena cava of man. J. Clin. In vest., 32:1145, 1953.

8. Greiner, T., and Henry, J. P.: Mechanism of postural proteinuria. J.A.M.A., 157:

1373, 1955.

9. King,S. E.,and Baldwin,D. S.:Produc

tion of renal ischemia and proteinuria

in man by the adrenal medullary hor

mones. Am. J. Med., 20:217, 1956. 10. Slater, R. J.: In Proceedings of the

Eleventh Annual Conference on the Nephrotic Syndrome, 1959, to be pub lished.

(10)

ARTICLES 199

16. Klaus, R., Shallow, J., and Murphy, J. J.:

Effect of increasing pressure in the

renal veins and of obstruction to renal lymphatic outflow upon urinary pro tein excretion. Surg. Forum, 7:613,

1957.

17. Stirling, K.: The turnover rate of serum albumin in man as measured by I131@ tagged albumin. J. Clin. Invest., 30:

1228, 1951.

18. Webb, T., Rose, B., and Sehon, A.: Bio colloids in normal human urine. Canad.

J. Biochem.

&Physiol.,36:1159,1167,

1958.

19. Franklin, E. C.: Physiochemical and im munologic studies of gamma-globulins

of normal human urine. J. Clin. Invest.,

38:2159,1959.

ments during orthostasis in patients with acute and chronic renal diseases.

J. Clin.Invest.,33:1457,1954.

12. Lathem, W.: Renal circulatory dynamics

and urinary protein excretion during

infusions of l-norepinephrine and I epinephrine in patients with renal dis ease. J. Clin. Invest., 35:1277, 1956. 13. Pappenheimer, J. R.: Passage of mole

cules through capillary walls. Physiol. Rev., 33:387, 1953.

14. Lassen, N. A., Longley, J. B., and Lilien field, L. S.: Concentration of albumin in renal papilla. Science, 128:720, 1958. 15. LeBrie, S.: In Proceedings of the Eleventh Annual Conference on the

Nephrotic Syndrome, 1959, to be pub

(11)

1960;26;190

Pediatrics

R. J. Slater, N. J. O'Doherty and M. S. DeWolfe