1100

graphy (due to natural lysis of the autologous material after28 days), is further evidence for this mode of removal of

degraded fibrinogen/fibrin. Animal experiments are now beingnerformed to confirm our observations relating to the site of

destruction of fibrinogen. -Department of Surgery,Queen Elizabeth Hospital,University of Birmingham.

R. J. HAWKERLINDA M. HAWKERG. A. L. WILKINSONJ. D. HAMER

IS THE URINE CONCENTRATING ABILITYDEFECTIVE IN THE AFRICAN?

SIR,-In a study of 7 Nigerians and 4 Europeans residentin Lagos, Nigeria, Kenney’ reported that the maximum urineconcentration was greater in European than in Nigerian sub-jects, no matter how he provoked hydropxnia. In a laterreview article2 Kenney stated that the mechanism of urine con-centration is defective in the African.

In my view the urine-concentrating ability is no less ade-

quate in the African than in the European. This view is basedon studies of 60 healthy Ghanaians (West Africans), 16 ofwhom had haemoglobin AS (sickle-cell trait), and 44 haemo-globin AA.The sickle-cell trait subject has a moderately reduced ability

to concentrate urine.3 4 have confirmed this in my 16 sickle-cell-trait subjects; my patients with haemoglobin AA hadmaximum urine osmolalities ranging from 900 to 1300 mos-mol/kg (average over 1000) whereas those with the sickle-cell-trait had values ranging from 600 to about 1000 mosmol/kg(average 700). The range of values for Kenney’s Europeansubjects are similar to the range I obtained in my GhanaianHb AA subjects. Kenney did not record the haemoglobin geno-type of his subjects, because I think it was not determined. Inthe coastal belt West Africa about 25% of the population havethe sickle-cell trait.’ It is likely therefore that some of Kenney’sNigerian subjects had the sickle-cell trait, particularly thosewho had maximum urine osmolality consistently below 800mosmol/kg.

Clearly Kenney’s values for maximum urine osmolality inhis African subjects were a mixture of normal values for theHb AA and lower values for the Hb AS. The conclusion is ines-capable that the healthy African with Hb AA is capable of con-centrating his urine no less efficiently than the European.Department of Physiology,University of Ghana Medical School,P.O. Box 4236,Accra, Ghana. S. KOJO ADDAE

NURSES AND PHYSICIANS’ ASSISTANTS

SIR,-I I was disappointed to read the inaccurate,opinionated, unsigned article under this heading in yourRound the World section. In parts it sounded as though it hadbeen written ten years ago, since that is when the AmericanNurses Association (note the correct title) took the stand onbaccalaureate education, whereas this was changed severalyears ago--an action I consider unfortunate.When the A.N.A. adopted the policy statement requiring a

degree it was an attempt to have nurses educated at the samelevel as other young people, and to make them better able tocope with the large amount of medical knowledge availabletoday. Also, by being better educated the nurse could workwith the physician and other professionals on a more equalbasis. In addition, nursing leaders recognised that the care of

1. Kenney, R. A. J. trop. Med. Hyg. 1957, 60, 79.2. Kenney, R. A. Int. Rev. trop. Med. 1963, 2, 293.3. van Eps, L. W. S., Schouten, H., Romeny-Wachter, C. C. T. H., La Porte-

Wijsman, L. W. Clinica chim. Acta. 1970, 27, 501.4. Francis, Y. F., Worthen, H. G. J. natn. med. Ass. 1968, 60, 266.5. Konotey-Ahulu, F. I. D. The Sickle Cell Disease: the Case for Family Plan-

ning. Accra, Ghana, 1973.6. Lancet, 1975, i, 1333.

the patient required more understanding of the person withthe disease; social, cultural, and psychological factors were im-portant to the nursing care of patients, and to handle this thenurse needed a broader educational base. It is interesting thatothers are just now recognising this; but nurses are criticisedfor being ahead of the times.

Another way that nurses were ahead of the times was in thedevelopment of assistants, nursing aids, &c. Granted this wasforced on them in some ways, and the practical nurses them-selves demanded recognition and licensure. This seems to beone of your criticisms also. Still you seem to praise the phys-ician for developing assistants.1149 Arlington Parkway,Atlanta, Georgia 30324, U.S.A. MARY LOUISE ATKINSON

IS PRE-ECLAMPSIA AN IMMUNE-COMPLEXDISEASE?

SIR,-As pointed out in your editorial (Sept. 13, p. 487), thebasic pathological mechanism underlying hypertension in

pregnancy continues to be elusive. I suggest that arthritis maysometimes be a feature of the pre-eclamptic syndrome (P.E.T.)and that more investigation based on the possibility of an im-mune-complex disease may well prove fruitful.

I have had the opportunity of talking to 6 women who,when pregnant felt they had mild arthritic symptoms affectingtheir proximal interphalangeal joints. Of the 6, 3 had beenworried that they might be developing rheumatoid arthritis, 5had a close family history of autoimmune disease, and at fol-low-up one year later 2 felt they had painless residual jointswelling and had found it necessary to have their ringsenlarged.

79 randomly selected pregnant women were then studied todetermine whether there was an association between fingerswelling and an increased erythrocyte sedimentation-rate

(E.S.R.). The E.S.R. was between 50 and 150 mm in the firsthour in 25 patients (31.6%), and of these 15 (60%) had fingerswelling. In the group with an E.s.R. below 50 mm, only 14 ofthe 54 patients (16%) had finger swelling. The correlationbetween finger swelling and elevation of the E.s.R. is significant(P<0.005).

Assuming that there is such an entity as an arthritis of preg-nancy, it may be speculated that glomerulonephritis, hyperten-sion, oedema, intravascular coagulation, placental insuffi-ciency, and arthritis are all aspects of a type-nthypersensitivity state, in which fetal antigenic material crossesthe placenta and stimulates a maternal antibody response. Theresponse may be poor, in which case the mother has a largeantigen excess, no pathological immune complexes are formed,and she remains free from disease. Those mothers who have anintermediate response are liable to form immune complexeswith slight antigen or antibody excess. Such complexes persistin the circulation, activate complement, and lead to small-ves-sel injury.’ This may be manifest clinically as P.E.T. Mothersin whom the response is good quickly develop a large antibodyexcess and are free from disease.

Since the primigravid patient is encountering fetal antigensfor the first time, her primary antibody response is unlikely tobe good and she runs the risk of being an intermediate res-ponder. In subsequent pregnancies, however, she is likely tomount a good secondary response and she rapidly enters the"safe" zone of large antibody excess. Hence, the facts wellknown to obstetricians, that primigravidae are more susceptibleto P.E.T. and that a previous abortion offers some protectionfrom the condition are supported by this theory.A possible immunological aetiology of P.E.T. has often been

considered.2 3 However, conclusive evidence is unlikely until a

1. Cochrane, C. G., Dixon, F. J. in Textbook of Immunopathology (edited byP. A. Miescher and H. J. Muller-Eberhard); Vol. 1, p. 94. New York,1968.

2. Kitzmiller, J. L., Benirschke, K. Am. J. Obstet. Gynec. 1973, 115, 248.3. Petrucco, O. M., Thompson, N. M., Lawrence, J. R., Weldon, M. W. Br

med. J. 1974, i, 473.