FACTOR VIII AND GLOMERULONEPHRITIS

1111 REFERENCES

Phenylketonuria (edited by F. Lyman); p. 52. Springfield, Ill., 1963. Smith, I. Archs Dis. Childh. 1974, 49, 245. Justice, P., O’Flynn, M. E., Hsia, D. Y. Lancet, 1967, i, 928. McClean, A., Marwick, M. J., Clayton, B. E. J. clin. Path. 1973,

Jervis,

1. 2. 3. 4.

G. A. in

26, 678. 5. Bartholomé, K. Lancet, 1974, ii, 1580. 6. Crome, L. J. Neurol. 1962, 25, 149. 7. Kaufman, S. Adv. Enzymol. 1971, 35, 245. 8. Blakeley, R. L. The Biochemistry of Folic Acid and Related Pteridines): vol. XIII in the series Frontiers of Biology (edited by A. Neuberger and E. L. Tatum). Amsterdam, 1969. 9. Jacobson, W. in Some Recent Advances in Inborn Errors of Metabolism: Symposium 4 of the Society for the Study of Inborn Errors of Metabolism (edited by K. S. Holt and V. P. Coffey);

p. 1. Edinburgh, 1968. 10. Jacobson, W. Personal communication.

Addendum Fig. 4-Hydroxylation of phenylalanine biopterin (after Kaufman’).

to

tyrosine and role of

XH,=dihydrobiopterin. XH4=tetrahydrobiopterin. This compound, in for phenylalanine hydroxylase. its active tetra-hydro form, donates hydrogen ions during the hydroxylation reactionand is converted to quinonoid-dihydropteridine. This is converted back to tetrahydrobiopterin by the enzyme dihydroThe same co-factor system pteridine reductase (fig. is used in neural tissue for the hydroxylation of tyrosine to dihydroxyphenylalanine (levodopa) in the synthesis of the amine transmitters, dopamine, noradrenaline, and adrenaline, and also of tryptophan to 5-hydroxytryptophan in the synthesis of serotonin. Thus a deficiency of biopterin or of the enzyme dihydropteridine reductase, would not only impair the hydroxylation of phenylalanine to tyrosine, but also interfere

4).

with the production of neurotransmitters in the brain. Such a defect might be expected to cause severe neurological disease. Phenylalanine restriction, which would correct the hyperphenylalaninaemia without affecting the block in transmitter production, would be unlikely to benefit the neurological symptoms. Levodopa and dopamine play an important part in the function of the basal ganglia, and clinically this part of the brain appeared to be involved early in the course of the illness. All the features of these cases can be explained on the basis of a defect in biopterin metabolism. Jacobsonhas pointed out that pterins may have a part to play in the treatment of phenylketonuria, and an even stronger argument exists for a trial of such compounds in patients with a suspected co-factor defect. We were unable to obtain biopterin in sufficient quantities for a clinical trial when our patients were still alive, but we have since learnt 10 that 6,7-dimethylpterin, an analogue of biopterin, can be synthesised with relative ease. This compound is active in vitro, though less so than biopterin, and it could be used in a therapeutic trial. We thank Dr Ann McLean for her assay of phenylalanine p-hydroxylase; Dr J. Wilson, Dr E. Brett, and Dr K. Holt for their comments on the patients’ neurological illness; Dr G. Pampiglione for the E.E.G. reports; Dr J. N. Montgomery and Dr T. H. Hughes-Davies for referring the patients to us; and the Department of Health and Social Security and the

Wellcome Trust for financial support. Requests for reprints should be addressed to 1. S., Department of Child Health, Institute of Child Health, 30 Guilford Street, London WC1N lEH.

In an abstract (Pediat. Res. 1975,9,348) 1. J. Butler, N. A. Holtzman, S. Kaufman, S. H. Koslow, A. Krumholz, and S. Milstien have lately reported dihydropteridine-reductase deficiency in a patient with phenylketonuria unresponsive to dietary treatment.

FACTOR VIII AND GLOMERULONEPHRITIS M. EKBERG

I. M. NILSSON

Renal Unit and Coagulation Laboratory, Department Internal Medicine, University of Lund, Allmänna Sjukhuset, Malmö, Sweden

of

To find out if determination of factor VIII, which most probably is synthetised in the intima of blood-vessels, is of value for predicting the severity of vessel damage in glomerulonephritis, factor-VIII activity, factor-VIII-related antigen, and glomerular filtration-rate were estimated in 85 patients with early glomerulonephritis on admission, and in 70 of these at follow-up for up to 4 years.

Summary

The levels of factor-VIII activity and factor-VIII-related antigen on admission were normal in those patients who recovered. Where renal function was impaired or became so during follow-up, factor high. Determination of factor VIII might thus be of prognostic value in early glomerulonephritis.

on

admission

VIII was

Introduction

Bloom et aLl and Hoyer et al.2.3 have identified factor-vni-related antigen in normal vessel walls and glomerular capillary endothelium by an indirect immunofluorescent technique. The antigenic protein in the intima is not due to adhesion of the factor from the blood; Holmberg et al found that infusion of large doses of factor-vm concentrate to four patients with von Willebrand’s disease, in which intimal factor vm is totally lacking, did not result in the appearance of any specific fluorescence in the intima. This

suggested synthesis of the protein by the endothelial cells of the vessel wall, and corroborated the finding of factor-vm-antigen production in cultures of fetal endothelial cells by Jaffe et al. In glomerulonephritis, the endothelium of the glomerular vessels is damaged by deposition of complement and the consequent inflammatory reaction,6 which is followed by aggre-

1112

gation of platelets and a local intravascular coagularesulting in formation of fibrin deposits in the glomeruli. Factor VIII is also thought to stimulate platelet aggregation/adhesion 7,8and thereby to enhance the deposition of fibrin in glomerulonephritis. We therefore decided to study factor-vm activity, and especially the factor-vui-related antigen, on the assumption that the degree of initial endothelial damage in glomerulonephritis might be closely related to the ensuing severity of glomerular damage. tion

Patients and Methods Patients

We investigated 70 patients admitted to hospital because of proteinuria and/or haematuria and suspected glomerulonephritis. The diagnosis was supported by renal biopsy. Renal function, as judged from three consecutive serum-creatinines, 24-hour endogenous creatinine clearance, and, in some cases, 51Cr-E.D.T.A. clearance, was normal in 64 patients but moderately reduced in the remaining 6. These patients were followed for up to four years and were divided into four groups according to the serum-creatinine and the degree of albuminuria and haematuria at the end of the follow-up period (table I).

Factor-VIII activity and factor-VM-related antigen on admission in the four groups.

present was expressed as a percentage of that found in a standard consisting of pooled plasma from 20 healthy controls. Normal range 60-160%. Factor-vm-related antigen was immunologically determined by electrophoresis in agarose gel containing antibodies, as described by Holmberg and Nilsson.11 Normal

TABLE I-LIGHT-MICROSCOPIC FINDINGS IN BIOPSY SPECIMENS OF KIDNEY IN THE FOUR GROUPS

range

60-160%. Results

I &mid ot;

Refers

to

glomerulonephritis

I

I

Renal function on admission was normal in 14 of the patients in group 1, but moderately impaired in 1 (G.F.R. 60 ml. per minute). All had albuminuria, and this exceeded 1 g. per litre in 7 of the patients. Factorviii activity and factor-vm-related antigen were normal (figure, table II). In the 1 patient with impaired renal function factor-vui activity bordered on the upper limit (160%) of normal. All 15 patients made

I

unless otherwise specified.

Factor-VIII activity and factor-vm-related antigen assessed on admission and at various times during follow-up in all these patients. 15 patients recovered completely (group 1); 25 who still had albuminuria and hsematuria but whose serumcreatinine increase did not exceed 0’2 mg. per 100 ml. were assigned to group 2; 17 had a serum-creatinine increase by 0-3-1 mg. per 100 ml. and still had proteinuria and haematuria (group 3); and the remaining 13 in whom renal function had deteriorated and the serumcreatinine had increased by more than 1 mg. per 100 ml. were assigned to group 4. We also studied the factor-vm activity and related antigen, but only on admission, in another 15 patients with glomerulonephritis and impaired renal function, as judged from the 51Cr-E.D.T.A. clearance.

a

were

Methods Serum-creatinine (Technicon method), 24-hour endoclearance, Addis quantitative sediment, and urinary albumin (immunologically) were measured with standard techniques at the Department of Clinical Chemistry. 51Cr- E .D. T .A. clearance was determined by the method of Bröchner-Mortensen.9 Factor-viii activity was assessed on platelet-rich haemophilia A plasma in a recalcification system according The amount of anti-haemophilic factor to Nilsson et al.10 genous creatinine

.

complete

recovery.

In 24 of the patients in group 2 renal function was normal on admission and during follow-up, but albuminuria and/or haematuria persisted; in many cases factor-vm assays were above the normal range. 1 patient had a 51Cr-E.D.T.A. clearance of 55 ml. per minute and an A.H.F. activity of 225 %. Factor-vm activity and factor-vm-related antigen were high on admission in patients in whom permanent renal damage with renal insufficiency subsequently developed (figure, table II). During follow-up these high values persisted or rose. The differences between II-MEANS AND S.D. OF FACTOR-VIII ACTIVITY AND FACTOR-VIII-RELATED ANTIGEN IN FOUR GROUPS OF PATIENTS WHO WERE FOLLOWED UP

TABLE

1113

the

mean

This investigation was supported by grants from the Swedish Medical Research Council (B75-19X-87-11A; B7519X-4541-01) and the Medical Faculty, University of Lund.

values between group 1 and groups 3 and 4

highly significant (P<0-001). patients with glomerulonephritis and impaired renal function who were not followed up had a factor-vm activity of 160-350% on admission.

were

All 15

Requests for reprints should be addressed to M. E., Renal Unit, Department of Internal Medicine, Allmanna Sjukhuset, Maimo, Sweden. REFERENCES

Discussion

nephritis. In these

patients there

was a

discrepancy between

factor-vm activity and antigen, mostly

antigen

an excess

111. 11. 12.

Holmberg, L., Nilsson, I. M. Br. med. J. 1972, iii, 317. Jamieson, G. A., Urban, C. L., Barber, A. J. Nature 1971, 234, 5.

new

Biol.

WEIGHT CARRYING AFTER MYOCARDIAL

INFARCTION D.

J. B.

IRVING A. L. MUIR

J. EWING F. KERR

University Department of Medicine, Royal Infirmary, Edinburgh EH3 9YW

The blood-pressure responses to Scarrying um ary a 15 kg. weight in a shoppingin on the back, were compared and a rucksack basket, in 13 ambulant male patients who were convalescing from an uncomplicated myocardial infarction. In 8 of the patients a sustained-handgrip test was also performed. Carrying the wéight in the hand produced a distinct increase in blood-pressure, which did not occur when the weight was carried on the back. There was also a significant increase in blood-pressure during sustained handgrip. In view of the lack of symptoms with these circulatory changes, it is concluded that more specific advice about the possible dangers of sustained static exercise should be given to patients recovering from myocardial infarction.

of

activity, as was also found by Holmberg et a1.4 No explanation for this discrepancy can be offered without further knowledge of the structure over

of the factor-vm molecule. Prentice et al.7 and Vermylen et all have shown that human platelets are aggregated in vitro by purified bovine and porcine high-molecular-weight factor VIII. They proposed that sialyl transferase in the platelet membrane complexes with exposed galactose residues in the factor-vm protein, which contributes to the aggregation of platelets. Besides the adhesion of the platelets to the collagen in the basement membrane,12 the increased A.H.F. protein in glomerulonephritis might thus be of importance to initiate primary hzemostasis and consequently intravascular

coagulation.

Bloom, A. L., Giddings, J. C., Wilks, C. J. Nature new Biol. 1973, 241, 217. 2. Hoyer, L. W., De Los Santos, R. P., Hoyer, J. R. J. clin. Invest. 1973, 52, 2737. 3. Hoyer, J. R., Michael, A. F., Hoyer, L. W. ibid. 1974, 53, 1375. 4. Holmberg, L., Nilsson, I. M. Scand. J. Hœmat. 1974, 12, 221. 5. Jaffe, E. A., Hoyer, L. W., Nachman, R. L. J. clin. Invest. 1973, 52, 2757. 6. Merrill, J. P. New Engl. J. Med. 1974, 291, 374. 7. Prentice, R. M., Hassanein, A. A., McNicol, G. P., Douglas, A. S. Br. J. Hœmat. 1972, 23, 541. 8. Vermylen, J., Donati, M. B., de Gaetano, G., Verstraete, M. Nature, 1973, 244, 167. 9. Bröchner-Mortensen, J., Giese, J., Rossing, N. Scand. J. clin. Lab. Invest. 1969, 23, 301. 10. Nilsson, I. M., Blombäck, M., Ahlberg, Å. Bibl. hœmat. 1970, 34, 1.

Factor-vm activity and related antigen were normal in the patients who made a complete recovery, but high in patients whose renal function deteriorated. In half of the patients in group 1, some of whom had nephrotic conditions, albumin excretion exceeded 1 g. per litre. In groups 3 and 4 albumin excretion did not differ significantly from that in group 1, and is of no prognostic value. Cr-E.D.T.A. clearances were unhelpful too; values were low in the 15 patients with renal impairment on admission, but inspection of clearance values for the four followup groups revealed no striking differences. Renal function, as judged by serum-creatinine and endogenous creatinine clearance, was normal in most patients in groups 1, 3, and 4, yet the groups did differ significantly in factor-vm activity and antigen. Since it now seems likely that factor-vm protein is synthetised by the endothelial cells of normal vessel intima and since Hoyer et al. have found an increased amount of A.H.F.-related antigen in the capillary endothelial cells in glomerulonephritis, the injury to the vascular endothelium in glomerulonephritis might lead to an increase in the amount of the protein in plasma. A.H.F. increases rapidly in various conditions with increased tissue breakdown and repair.4 The underlying mechanism is not known. We thought that factor-vm activity and factor-vm-related antigen might reflect the vessel damage in glomerulonephritis, especially since factor vm was high in all 15 patients with impaired renal function. Yet in most of the patients with high levels of factor VIII (groups 3 and 4) renal function was normal on admission as judged by serum-creatinine and endogenous creatinine clearance. But more refined clearance methods might have revealed impairment of function in several of the patients in groups 3 and 4. On the other hand, glomerular filtration might be normal even in the presence of severe vessel damage in glomerulo-

Introduction HEAVY rhythmic (or dynamic) exercise, such as walking, running, or cycling, rapidly produces subjective symptoms. Most patients who know that they have recently suffered a heart-attack will avoid such activities, both on the advice of their doctor and on the instinctive assumption that any such activity causing symptoms must also be causing a strain on The same is not true, however, for their heart. sustained (or static) exercise, such as carrying a suitcase, pushing a car, or moving a piece of furniture, where dramatic increases in blood-pressure may take place without the subject being aware of them.l The blood-pressure rise depends largely on the percentage of maximum effort performed by any particular muscle-group.l,2 The larger the percentage, the greater