samnplinig and -...

METABOLISMOF WOMENDURINGTHE REPRODUCTIVECYCLE.XVII. CHANGESIN ELECTROPHORETICPATTERNSOF

PLASMAPROTEINSTHROUGHOUTTHE CYCLEANDFOLLOWINGDELIVERY"2

By MARGARETN. CORYELL, ELIOT F. BEACH,3 ABNERR. ROBINSON,ICIE G. MACY, AND HAROLDC. MACK

(From the Research Laboratory, Childrent's Futnid of Michigan, anid Thze Departmielnt ofObstetrics antd Gynecology, Harper Hospital, Detroit)

(Submitted for publication July 17, 1950; accepted, August 28, 1950)

The present investigation, an electrophoreticstudy of blood proteins, was planned to obtaininformation concerning the preconceptional physi-ologic status of women, the physiologic changes inthe maternal organism in preparation for the exi-gencies of labor and losses at delivery, for thereadjustment during the puerperium, and the de-mands of lactation. The results of this study willprovide the basis for a better understanding ofelectrophoretic determinations of the proteins inthe blood of women whose child-bearing was com-plicated by abnormal conditions or disease (1).

While this investigation was in progress (2)the Tiselius procedure (3) for electrophoretic sep-aration of blood proteins was applied to maternal,fetal, and infant sera by Longsworth, Curtis andPembroke (4), Lagercrantz (5), Moore, DuPanand Buxton (6), and Scrimshaw and Alling (7)in studies of placental permeability and toxemiasof pregnancy but, to our knowledge, this is thefirst report of electrophoretic determinations ofconstituents of the blood of healthy womenthrough-out the reproductive cycle, from the preconcep-tional state through the postpartum readjustmentperiod. The observations on cord blood will bepresented in another communication.

METHODSAND MATERIALS

Healthy, well-nourished women in the early stages ofgestation were selected from among his private patients

1 A preliminary report of the material in this paper waspresented before the American Society of BiologicalChemists at the 33rd Annual Meeting of the Federationof American Societies for Experimental Biology, Detroit,April 18-22, 1949.

2 This investigation was partially supported by a grantfrom The Nutrition Foundation, Inc., New York.

3 Present address: Biochemical Laboratory, Metropoli-tan Life Insurance Company, 1 Madison Ave., NewYork 10, N. Y.

by the obstetrician (H. C. M.) on the basis of medicalhistory and examination. The subjects were average orabove in economic level and leading normal family lives.They were consuming good diets and clinically were con-sidered well-nourished before, during, and after preg-nancy. Since longitudinal data have greater value thancross-sectional data under known environmental condi-tions during growth (8) and when a physiologic processis involved (9), insofar as possible the same subjects werestudied before conception, and throughout pregnancy, de-livery, and postpartum, thus providing both types of re-sults and minimizing difficulties in interpreting individualdifferences by using each subject as her own "control."Data were obtained with the same techniques for a groupof non-pregnant women who had never been pregnant.

Blood samnplinig and preparationBlood samples for chemical determinations of total pro-

tein and for electrophoresis were obtained during thethree trimesters of pregnancy, at delivery, and within 24hours, five to six days, and six to 12 weeks postpartum.Samples were obtained from finger punctures for evalua-tion of nutritional status. Since the subjects were livingat home and blood samples were procured at times ofexamination by the obstetrician, the women were notalways in a fasting state when blood was withdrawn.

Blood was withdrawn from a vein in the antecubitalfossa with minimum stasis which might affect the pro-teins (10), usually between 10:00 a.m. and 2:30 p.m.As accurately as possible, 20 ml. were drawn and dis-charged into a 50 ml., glass-stoppered Erlenmeyer flaskcontaining 3 ml. of 2.5 per cent sodium citrate in physio-logic saline solution. After mixing the contents thor-oughly the flask was placed in a refrigerator pendingtransportation to the laboratory, usually less than twohours. At the laboratory the volume was measured witha calibrated pipette and the blood centrifuged under re-frigeration for 30 minutes at 13,000 r.p.m.

Determtinations of total proteinzTotal protein was estimated in aliquots of plasma from

venous blood. The methods employed were the gravi-metric acetone precipitation procedure (11) and themicro-Kjeldahl procedure (12) using 6.25 as the factorfor converting nitrogen to protein and correcting thenitrogen value for non-protein-nitrogen by assuming an

1559

M. N. CORYELL, E. F. BEACH, A. R. ROBINSON, I. G. MACY, AND H. C. MACK

average content of 35 mg. in 100 ml. of plasma. In thecalculation of data presented in this paper gravimetricdata were used, except with a few samples for whichvalues were not available.

Electrophoretic techniqueThe sodium barbital buffer solution recommended by

Longsworth (13) as most suitable for analyses of humansera or plasma was used for dilution. Dialysis 4 of plasmasamples was continued for at least 72 hours at 40 C. inpreparation for electrophoretic study. The electrophoreticrecordings were made with a Tiselius instrumeint 5 em-ploying the Longsworth (14, 15) scanning mechanismand a three-piece Tiselius cell with a single long centersection. Most determinations were run for three hoursat 1° C. and a potential gradient of about 6 volts/cm.

The patterns recorded on the original plates, both as-cending and descending boundaries, were projected with aphotographic enlarger and traced at a linear enlargementof approximately 2.16 times original size. On the trac-ings, the areas attributable to the various componentswere defined by the method of Tiselius and Kabat (16),in which ordinates are drawn from the lowest point be-tween each two components to the base line. Each areawas measured with a precision disc planimeter 6 or a dif-ferential analyzer (17) and the relative concentrationswere determined by dividing the areas representative ofeach component by the area of the entire pattern minusthe area of the corresponding boundary anomaly. Fromthis percentage figure and the chemically-determined valuefor the total plasma protein, corrected for dilution andshrinkage, the actual plasma concentrations of the re-spective components were calculated. The areas werecomputed from both the ascending and the descendingboundaries, and the means used in calculating concentra-tions.

The ionic strength of buffer and blood sample, theprotein concentration of the sample, and the type of bufferaffect the values calculated for concentration of variousprotein components per 100 gm. of total protein from theelectrophoretic data (3, 13, 18). In this study these fac-tors were controlled as closely as possible to enhanice theaccuracy of the albumin/globulin ratio and reduce vari-ability in data owing to methods.

Boundary anomalies influence the electrophoretic mobili-ties and the relative distribution of the protein components(5, 13, 19, 20). Mobilities were calculated on the de-scending boundaries as advocated by Longsworth andMacInnes (21). Instead of the maximum gradients theordinates dividing the respective areas in half were usedas also suggested by these authors. The distances moved

4 Nojax-Visking Cellulose Sausage Casing was usedfor dialysis. It was obtained from the Visking Corpora-tion, 6733 West 56th Street, Chicago 31, Ill.

5 Klett Manufacturing Company, 179 East 87th Street,New York City, N. Y. Although the manufacturer'sspecifications indicated that the center section of the cellhad a capacity of 11 ml., the actual size was 9 + ml.

6 G. Gorado, Zurich, Switzerland.

by the various peaks were measured from the salt anom-aly, epsilon, instead of the starting boundary. In 28 sam-ples of maternal plasma the mobilities were extremelyconstant, the ranges for albumin, alpha1, alpha2, beta, phi,and gammabeing, respectively: 6.18-6.65; 5.10-5.61; 3.55-4.46; 2.92-3.40; 2.22-2.54; and 1.28-1.58 cm.2/sec./voltX 10-5.

In addition to the chemical determinations, the totalprotein of dialyzed plasma samples was calculated fromthe total electrophoretic pattern areas as described byAbramson, Moyer and Gorin (22) and by Longsworth,Curtis and Pembroke (4). Plasma protein values ob-tained by either chemical or electrophoretic method werecorrected for the diluting effect of the anticoagulant solu-tion by calculations (4, 23).

According to data published by Dieckmann and Wegner(24, 25), the average ratios between hemoglobin and cellvolume remain fairly constant throughout pregnancy andafter gestation. Because of the rather large variation inhematocrit values, especially in pregnancy, it was felt thatcell volumes calculated from the hemoglobin values onthe basis of the average ratio, 0.34, found by Wintrobe(26) would be more reliable than an average figure forcell volume.

In evaluating the significance of differences among re-sults for blood from non-pregnant women and from sub-jects at various stages of pregnancy and postpartum, the"t test" for small samples (27) was employed after check-ing by the Chi Square test that the assumption of normaldistribution for all the protein fractions was justified.

A\uttritional status determninationsIn blood samples obtained by the technique of Bessey

and Lowry 7 hemoglobin (28) and serum protein (29)were determined immediately after collection and prep-aration of the samples. Then, samples of serum andprotein-free filtrates of serum were prepared and meas-ured into microtubes, which were stored at - 300 F. fordeterminations of vitamin C (30, 31), alkaline phospha-tase (32), vitamin A and carotenoids (33, 34).

RESULTS AND DISCUSSION

The subjects of this study were women of nor-

mal size, and their gestational weight gains rangedfrom 10 to 37 pounds. Ten to 21 subjects gainedmore than 25 pounds during pregnancy, which isfrequently considered undesirable (35). The ba-bies delivered by the mothers were all full termand healthy, none weighing less than 6 pounds atbirth (36).

7 The Research Laboratory of the Children's Fund ofMichigan was extended the privilege by Drs. Otto A.Bessey and Oliver H. Lowry of sending a representativeto the Medical Research Institute, Department of Healthof the City of New York, for training in their microchem-ical blood techniques shortly after they were developed.

1560

METABOLISMOF WOMENDURING REPRODUCTIVECYCLE. XVII

The values for all components determined in theblood for ascertaining the nutritive state of thewomen were within the ranges considered to benormal for that period in the reproductive cycle.Hemoglobin ranged from 10.4 to 15.3 gm. per 100ml. of blood, with the highest values being foundin samples obtained several weeks postpartum andthe lowest values in samples for the second one-half of pregnancy and in the first week postpartum.By the gradient tube micromethod, serum proteinconcentrations ranged from 5.45 to 7.20 gm. per100 ml. Values for serum vitamin C variedwidely, with values as low as 0.37 and as high as2.78 mg. per 100 ml. From 1.0 to 9.7 nitro-phenol units (millimoles nitrophenol formed perliter per hour) of alkaline phosphatase were found.Values as high as 9.7 units are not uncommon inthe later weeks of pregnancy (37), as will be con-firmed in a subsequent publication (38). Levelsof vitamin A and carotenoids were within theranges usually found.

Data from determinations of total protein andelectrophoresis of the protein fractions in all sam-ples of plasma from non-pregnant women andmothers during the reproductive cycle are sum-marized 8 in Table I. Electrophoresis values forindividual proteins are given per 100 gm. ofplasma protein and per 100 ml. of plasma.

The average values for total protein decreasedsomewhat during pregnancy, being 13 per centbelow the non-pregnant value in the third tri-mester. The effect of this change with those pro-tein components which decreased in concentrationper 100 gm. of protein during pregnancy wouldbe to emphasize the decrease on the basis of 100ml. of plasma, whereas for components which in-creased during pregnancy, the increase would beless marked on the basis of concentration per 100ml. of plasma. The increases in plasma volumewhich are known to occur during pregnancy alsowould tend to widen the differences between valueson the basis of concentration in protein and inplasma.

Values from determinations in 22 samples ofplasma from 12 healthy non-pregnant women aregiven first in the table. Two of the women gave

8 Results of determinations for the individual womenwill be included in the publication presenting the completeresults of the study of maternal nutrition during the re-productive cycle.

four blood samples at weekly intervals in the ovu-lation cycle. One of these (Subject 23) subse-quently became pregnant, providing the oppor-tunity to study the changes in her electrophoreticpattern during the reproductive cycle in relation toher own preconceptional pattern. Since all of thevalues obtained for a single individual representher plasma protein pattern over a period of time,all determinations for the same individual wereaveraged and the results used in calculating themeans for the 12 individuals.

Other investigators have reported values forprotein components of serum and plasma obtainedby several methods. In total protein, the meanconcentrations for non-pregnant women given inTable I compare favorably with those found for15 normal adult males by Dole and Braun (39),although the values for alpha2 globulin andfibrinogen are, roughly, 15 and 20 per cent higher,respectively, than they reported. The values alsoagree well with those obtained by Armstrong,Budka and Morrison (20) with 20 pooled samplesof plasma from normal subjects. On the basis ofplasma concentration, the data for protein com-ponents reported by Dole and Braun were lowerthan those given in the table. Lagercrantz (5),using a refractometric method, found an averageserum protein value of 7.61 gm. per 100 ml. for16 normal women and with a colorimetric methoda mean of 7.42 gm. per 100 ml. plasma was foundfor 15 normal young womenby Plass and Matthew(40). The total serum protein of maternal blooddetermined from the total pattern area by Longs-worth, Curtis and Pembroke (4) averaged 7.17gm. per 100 ml.

The plasma albumin/globulin ratios for non-pregnant women cover a rather wide range, witha mean value lower than the 1.53 reported byDole and Braun (39), and 1.48 by Plass andMatthew (40). The ratios plotted in Figure 1 foreach period in the reproductive cycle show thedecreases consequent to lowered albumin con-centration and higher globulin concentration dur-ing pregnancy, with the return postpartum towardthe non-pregnant relationship.

The individual determinations for the varioussubjects during their reproductive cycles por-trayed variations attributable to differences amongthe women and the times in the cycle that theblood samples were drawn. For one woman (Sub-

1561


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ject 23) four blood samples taken at weekly inter-vals between the two menstrual periods imme-diately prior to pregnancy were analyzed; afterconception, samples were analyzed in each tri-mester of pregnancy, at delivery, and at threeintervals postpartum. The ascending electropho-retic patterns obtained for this subject at the latestpreconceptional time, throughout the cycle, and inthe cord blood are reproduced in Figure 2. Withthese longitudinal results it has been possible tocompare the changes in the plasma proteins ofthe same woman from the preconceptional statethrough postnatal readjustment with the meancross-sectional values for all subjects during preg-nancy, the puerperium, and subsequently.

The distributions of the components in the pro-tein showed a remarkable conformance betweenthe patterns for one womanand those of the meansfor all subjects, especially between the preconcep-tional pattern of Subject 23 and that of the meansfor 12 non-pregnant women. On the basis ofplasma composition the distributions of the pro-tein fractions corresponded, but greater variationwas apparent between the levels for Subject 23n"rl +'ha M'An"Q ;nr +thQ erri-in A1thoniirlkt +thie

PREGNNCY

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FIG. 2. ELECTROPHORETICPATTERNSOF THE PLASMAOFONEWOMANBEFORECONCEPTION, DURING PREGNANCY,AND POSTPARTUM;AND OF HER CoRD BLOOD

dLIU LIIV IlLC11O lUIJ LI1 g1 YUJL. £ ILLIAIUgwoman's values follow the trends of theaverages they are not always of themagnitude.

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FIG. 1. ALBUMIN/GLOBULIN RATIOS DURINGREPRODUCTIVECYCLE

Lgroupl~; That the unusual degree of conformance of thesame data for Subject 23 with those for the group was

coincidental was demonstrated by other individualvariations and emphasizes the importance of learn-ing more about the individual physiological char-acteristics of different women as they proceedthrough the reproductive cycle. Her greater vari-ation from the means for the group on the basisof concentration in plasma probably is attributableto individual variation of the blood volume of Sub-ject 23 from the mean volume of the group.

/0° The changes in plasma protein composition dur-/o° ing reproduction were compared by the differences/ ° of means during pregnancy and postpartum from

the mean values for all non-pregnant subjects.The results of statistical calculations of the sig-nificance of the differences were determined. Ingeneral, trends for albumin and gamma globulinwere downward and for alpha,, alpha2, beta, andphi (fibrinogen) globulins were upward until de-livery or later. Subsequently, the trends were

6-12 reversed and values approached those of the non-wee

Mrt= pregnant state.THE During the first trimester of pregnancy the de-

creases in albumin and gammaglobulin were sta-

1563

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tistically significant on the basis of plasma concen-tration, but per 100 gm. of total protein only thedecrease in gammaglobulin was significant. Theincreases in the other four protein fractions werenot significant per 100 ml. of plasma but foralpha,, alpha2, and phi globulins, the increases per100 gm. of protein were significant.

In the second trimester the concentrations of al-bumin and gammaglobulin in total protein and inplasma were reduced significantly. The increasesin the other components were statistically signifi-cant in terms of total protein but were not interms of plasma.

All differences for the final trimester were sig-nificant in relation to non-pregnant values, and foralbumin, alpha2, and beta globulin the differencesfrom second trimester values were significant, onthe bases of both protein and plasma concentra-tions.

At delivery, also, all differences from non-preg-nant values were significant and none of the meansshowed any significant deviation from those of thethird trimester. The fact that differences betweenmean values at delivery were not significant fromthose for the third trimester, on the basis of con-centrations in either total protein or plasma, wouldnot support the report (41) of a large decrease inplasma volume during the final weeks of preg-nancy, since changes in the concentration of totalprotein were variable and the means in the thirdtrimester and at delivery differed by less than 2per cent. The results conform with those ofMcLennan and Corey (42) who found that "themean value at term was not significantly lowerthan that at the 36th week," and that all womendid not show a reduction in plasma volume priorto delivery.

The average values for the concentrations inmaternal plasma at delivery compare well withresults for comparable subjects reported recentlyby Longsworth and his associates (4), obtainedunder almost identical experimental conditions,recognizing that they recorded all data in termsof serum, which would make the relative values 5to 6 per cent higher owing to exclusion of thefibrinogen present in the samples.

Mean values for albumin and alpha, globulin inthe first day postpartum varied significantly frommeans at delivery on the basis of protein distribu-tion, but in plasma only the variation in albumin

concentration was meaningful by the statistical de-termination. The small number of determinationsfor this period limits the value of the averages butthe values are interesting in relation to the resultsfor five to six days after delivery.

Determinations on the fifth and sixth days -afterdelivery did not show any significant differencesfrom values for the first day postpartum, but thedifferences from values at delivery were significantfor albumin and alpha, globulin on both the pro-tein and plasma bases. In addition, the mean foralpha2 globulin concentration in total protein fiveto six days postpartum was significantly differentfrom the figure for delivery. All componentsvaried significantly from the non-pregnant values.

The means of the determinations six to 12 weekspostpartum were significantly different in all in-stances except one, on both the basis of total pro-tein and of plasma, from the values for five to sixdays postpartum and those at delivery. By thattime after delivery only the mean for albumin per100 ml. plasma and the means for alpha1 globulinper 100 gm. protein and per 100 ml. plasma, andbeta globulin per 100 gm. protein were signifi-cantly different from the means for non-pregnantwomen.

Through pregnancy to five to six days there-after, total protein values were irregularly lowerthan those found for non-pregnant women, withdecreases in some components opposed to increasesin others. In evaluating plasma protein changesduring the reproductive cycle consideration mustbe given to the fact that reductions in concentra-tion of total protein in plasma do not indicate adecrease in total circulating protein because of theknown increases in blood volume during preg-nancy. We have emphasized individual physio-logic differences which must be recognized andwhich may influence interpretations of mean val-ues for a group of subjects.

Quantitatively, the decrease in albumin waslargest, the mean values five to six days post-partum (2.75 gm. per 100 ml. plasma) being 1.64gm. lower than the average (4.39 gm.) for non-pregnant women. The mean concentration ofgammaglobulin also was lower during pregnancy,from 0.91 gm. per 100 ml. of plasma in non-pregnant subjects to 0.49 gm. per 100 ml. five tosix days after delivery. Although this fraction isknown to carry many of the antibody materials of

1564


the blood and, in general, immunity may be re-lated to quantity of the globulin, it is probablethat immunity is related specifically to the pecu-liar characteristics of only a portion of that frac-tion. Reduction of gammaglobulin and albuminin plasma is usually associated with dietary pro-tein deficiency but observations and histories indi-cated that the subjects of this study consumedliberal amounts of protein during pregnancy, whichwould indicate that the changes in plasma proteinare attributable to physiologic alteration of metab-olism in pregnancy rather than to protein lackas such.

All the other globulin fractions rose in preg-nancy, generally reaching their maximum near de-livery. The mean for alpha, globulin, which roseregularly in pregnancy, exceeds that for gammaglobulin at five to six days postpartum. Of inter-est in this connection are the observations of Cha-nutin and Gjessing (43, 44), who, in dogs suffer-ing traumatic injury or destruction of tissue byinjection of nitrogen mustards, observed a fall inplasma albumin and a rise in the fast-movingglobulins. Similar influences may operate in re-flecting traumatic injury during labor or might beconnected with the rapidly occurring involution ofuterine musculature known to take place followingdelivery, coincident with the regressive change inplasma volume.

Stern and Reiner (45) pointed out that relativeprotein concentrations "computed from electro-phoretic data are affected to some extent by theionic strength and the protein concentration" andemphasized the limited number of normal valuesin the literature, the marked individual differencesin them, and the need for large series of observa-tions under closely controlled and uniform condi-tions to demarcate more accurately between normaland abnormal or pathological variations. Al-though Lagercrantz (5) used a phosphate bufferat a pH of 7.7 and an ionic strength of 0.15 inhis study of serum in pregnancy, the relative val-ues for the various component proteins showedchanges similar to those reported by Longsworthand co-workers (4) and to those shown in Table I.

Foster (46), on the basis of early chemicalanalyses, explained the increase in fibrin post-partum as a probable result of trauma incident tobirth, after Foster and Whipple (47) had con-cluded that hemorrhage led to a fibrin increase.

The mean fibrinogen values found in this studyindicate a consistent increase in that protein dur-ing pregnancy with higher values five to sixdays postpartum followed by a decrease to belowthe non-pregnant level six to 12 weeks after de-livery. Values for the four -women whose levelswere determined within 24 hours after their in-fants were born show that the greater part of theincrease in fibrinogen occurred prior to delivery,with maximum values during the first day post-partum and decreases by five to six days afterdelivery. At six to 12 weeks postpartum thevalues were essentially those of the preconcep-tional state. Apparently, instead of a fibrin in-crease in response to trauma during delivery, arelative increase in fibrinogen starts early in preg-nancy and continues until delivery, perhaps inanticipation of blood losses and trauma duringthe partum period.

The return of the plasma protein pattern towardnormal is almost complete by six to 12 weekspostpartum. The concentrations of total protein,albumin, and gamma globulin have risen and ofthe other globulins are reduced. This return tonormal seems to be uninfluenced by lactation or itssuppression, or the early re-establishment of men-struation, for mothers in none of these categoriesshowed variations which could be related to thoseconditions. This negative finding supports thebelief that protein demands as such are not thebasis for altered electrophoretic patterns in preg-nancy.

Changes in the blood proteins during pregnancyhave been the subject of numerous investigations.Until recently, however, the reports have pre-sented only the results of chemical determinationsof total protein or changes in the albumin, totalglobulin, and fibrinogen components (40, 48) asrevealed by precipitation procedures. Electropho-retic analysis of the proteins in serum or plasmaprovides a more detailed and reliable picture ofthis labile biological system than do other methods,used heretofore (3, 13, 45, 49, 50), although valuesare frequently lower than those obtained by chemi-cal methods. This new tool not only permits accu-rate estimation of the albumin/globulin ratio, butalso provides quantitative data for four distin-guishable components of plasma globulin, exclu-sive of fibrinogen.

1565


SUMMARY

This study comprises the results of electro-phoretic fractionation of plasma proteins from 93blood samples, 22 samples being from 12 healthynon-pregnant women, and 71 from 21 mothersduring uncomplicated pregnancy, at delivery, andat intervals postpartum. The same subjects were

studied at intervals during the reproductive cycle;one participated before conception, during preg-

nancy, and postpartum and contributed a total of11 blood samples.

All women were in satisfactory nutritional stateas indicated by results of microchemical bloodtests (including hemoglobin and protein, vitaminA, carotenoids, vitamin C and alkaline phosphatasein the blood serum) and by clinical observation.

The data demonstrate characteristic changes oftotal protein and plasma albumin and globulins(alpha,, alpha2, beta, and gamma fractions, andfibrinogen) during the reproductive cycle. Withinthe range of values, however, the different women

exhibited inherent variations in physiological per-

formance.The analysis of plasma proteins during the re-

productive cycle showed that:1. The mean values for total plasma protein

decreased during pregnancy, the mean amount inthe third trimester being 13 per cent below thenon-pregnant value.

2. On the basis of the concentration in plasmaprotein and in plasma there were statistically sig-nificant differences among mean values at intervalsin the reproductive cycle and mean values fornon-pregnant women.

3. Through delivery, plasma and protein con-

centration trends were consistently downward foralbumin and gammaglobulin and upward for thealpha,, alpha2, and beta fractions, and fibrinogen.

4. Five to six days after delivery, means forall protein fractions differed significantly from theaverages for non-pregnant subjects, both per 100gm. of plasma protein and per 100 ml. of plasma.

5. Six to 12 weeks postpartum the alpha, andbeta components differed significantly from thenon-pregnant average values on the basis of 100gm. of protein; albumin and alpha, differed sig-nificantly per 100 ml. of plasma. All other varia-tions from preconceptional levels were not statis-tically significant.

BIBLIOGRAPHY

1. Mack, H. C., Robinson, A. R., Wiseman, M. E., andSchoeb, E. J., Metabolism of women during thereproductive cycle. XVIII. Electrophoretic pat-terns of plasma proteins in toxemias of pregnancy.To be published.

2. Coryell, M. N., Beach, E. F., and Robinson, A.,Electrophoretic patterns of plasma proteins duringpregnancy and following delivery. FederationProc., 1949, 8, 192.

3. Tiselius, A., Electrophoresis of serum globulin. II.Electrophoretic analysis of normal and immunesera. Biochem. J., 1937, 31, 1464.

4. Longsworth, L. G., Curtis, R. M., and Pembroke,R. H., Jr., The electrophoretic analysis of maternaland fetal plasmas and sera. J. Clin. Invest., 1945,24, 46.

5. Lagercrantz, C., Electrophoretic analysis of serum inpregnancy and in pregnancy toxemia. Upsalalakaref. forh., 1945, 51, 117.

6. Moore, D. H., DuPan, R. M., and Buxton, C. L., Anelectrophoretic study of maternal, fetal, and infantsera. Am. J. Obst. & Gynec., 1949, 57, 312.

7. Scrimshaw, N. S., and Alling, E. L., Electrophoreticfindings in normal and abnormal pregnancy. Fed-eration Proc., 1949, 8, 368.

8. Wilson, E. B., Heights and weights of 275 publicschool girls for consecutive ages 7 to 16 years,inclusive. Proc. Nat. Acad. Sc., 1935, 21, 633.

9. Shuttleworth, F. K., The Physical and Mental Growthof Girls and Boys Age Six to Nineteen in Relationto Age at Maximum Growth. Soc. Research inChild Development, Monograph No. 3, NationalResearch Council, Washington, 1939.

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