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late thirties. It is possible that the microtubule assemblydefect of AD/SDAT type manifests at an early age in Downsyndrome.We thank Dr Raul Rudelli for special efforts to perform necropsies within

2-4 h, for sparing tissue for this study, and for the histopathological diagnosisof each case; Dr Lester I. Binder and Dr Anthony Frankfurter for supplyingthe monoclonal antibody to tau; Dr Maryanne Murtaugh and Mr

Christopher Thompson for help in preparation of neurofilaments andmicrotubules; Mrs Yunn-Chyn Tung for assistance in immunoblot analysisof the microtubule preparations; the Biomedical Photography Unit of ourInstitute for the photographic work; and Mrs Patricia Calimano for typingthis manuscript.

These studies were supported in part by National Institutes of Healthgrants NS 17487, NS 18105, AG/NS 04220, and AG 05892.

Correspondence should be addressed to K. I., NYS Institute for BasicResearch in Developmental Disabilities, 1050 Forest Hill Road, StatenIsland, New York 10314, USA.

REFERENCES

1. Iqbal K, Wisniewski HM. Neurofibrillary tangles. In: Reisberg B, ed. Alzheimer’sdisease, the standard reference. New York: Free Press, 1983: 48-56.

2. Kidd M. Paired helical filaments in electronmicroscopy of Alzheimer’s disease. Nature(Lond) 1963; 197: 192-93.

3. Wisniewski HM, Narang HK, Terry RD. Neurofibrillary tangles of paired helicalfilaments. J Neurol Sci 1976; 27: 173-81.

4. Wisniewski HM, Merz PA, Iqbal K. Ultrastructure of paired helical filaments ofAlzheimer’s neurofibrillary tangle. J Neuropathol Exper Neurol 1984; 43: 643-56.

5. Weisenberg RC. Microtubule formation in vitro in solutions containing low calciumconcentrations. Science 1972; 117: 1104-05.

6. Shelanski ML, Gaskin F, Cantor CR. Microtubule assembly in the absence of addednucleotides. Proc Natl Acad Sci USA 1973; 70: 765-68.

7. Iqbal K, Grundke-Iqbal I, Wisniewski HM, Terry RD. On neurofilament andneurotubule proteins from human autopsy tissue. J Neurochem 1977; 29: 417-24.

8. Iqbal K, Merz P, Grundke-Iqbal I, Wisniewski HM. Studies on mammalianneurofilaments isolated by in vitro assembly-disassembly. J Neuropathol ExpNeurol 1981; 40: 315.

9. Yan S-CB, Hwang S, Rustan TD. Human brain tubulin purification: decrease insoluble tubulin with age. Neurochem Res 1985; 10: 1-18.

10. Laemmli UK. Cleavage of structural proteins during the assembly of the head ofbacteriophage T4. Nature (Lond) 1970; 227: 680-85.

11. Lowry OH, Rosebrough NJ, Karr AL, Randall RJ. Protein measurements with Folinphenol reagent. J Biol Chem 1951; 193: 265-75.

12. Bensadoun A, Weinstein D. Assay of proteins in the presence of interfering materials.Analyt Biochem 1976; 70: 241-50.

13. Borisy GG, Olmsted JB. Nucleated assembly of microtubules in porcine brainextracts. Science 1972; 177: 1196-97.

14. Kirschner MW, Williams RC, Weingarten M, Gehart JC. Microtubules frommammalian brain: some properties of their depolymerization products and aproposed mechanism of assembly and disassembly. Proc Natl Acad Sci USA 1974;71: 1159-63.

15. Weingarten MD, Lockwood AH, Hwo SY, Kirschner MW. A protein factor essentialfor microtubule assembly. Proc Natl Acad Sci USA 1975; 72: 1858-62.

16. Sloboda R, Dentler W, Rosenbaum JL. Microtubule-associated proteins and thestimulation of tubulin assembly in vitro. Biochemistry 1976; 15: 4497-505.

17. Cleveland DW, Hwo SY, Kirschner MW. Physical and chemical properties of

purified tau factor and the role of tau in microtubule assembly. J Mol Biol 1977;116: 227-47.

18. Murphy DB, Johnson KA, Bonsy GG. Role of tubulin-associated proteins inmicrotubule nucleation and elongation. J Mol Biol 1977; 117: 33-52.

19. Lindwall G, Cole RD Phosphorylation affects the ability of tau protein to promotemicrotubule assembly. J Biol Chem 1984; 259: 5301-05.

20. Sackett DL, Bhattacharyya B, Wolff J. Tubulin subunit carboxyl termini determinepolymerization efficiency. J Biol Chem 1985; 260: 43-45.

21. Grundke-Iqbal I, Iqbal K, Tung YC, Quinlan M, Wisniewski HM, Binder LI.Abnormal phosphorylation of the microtubule associated protein tau in Alzheimercytoskeletal pathology. Proc Natl Acad Sci USA 1986; 83: 4913-17.

22. Binder LI, Frankfurter A, Rebhun LI. The distribution of tau in the mammaliancentral nervous system. J Cell Biol 1985; 101: 1371-78.

23. Wehland J, Henkart M, Klausner R, Sandoval IV Role of microtubules in thedistribution of the Golgi apparatus: effect of taxol and microinjected anti-&agr;-tubulinantibodies. Proc Natl Acad Sci USA 1983; 80: 4286-90.

24. Erickson HP, Voter WA. Polycation-induced assembly of purified tubulin. Proc NatlAcad Sci USA 1976; 73: 2813-17.

25 Hoffman PN, Lasek RJ. The slow component of axonal transport: Identification ofmajor structural polypeptides of the axon and their generality among mammalianneurons. J Cell Biol 1975; 66: 351-66.

26. Grundke-Iqbal I, Johnson AB, Wisniewski HM, Terry RD, Iqbal K. Evidence thatAlzheimer neurofibnllary tangles originate from neurotubules. Lancet 1970; i:

578-80.27. Kosik KS, Duffy LK, Dowling MM, Abraham C, McCluskey A, Selkoe DJ.

Microtubule-associated protein 2: Monoclonal antibodies demonstrate theselective incorporation of certain epitopes into Alzheimer neurofibrillary tangles.Proc Natl Acad Sci USA 1984; 81: 7941-45.

28. Ishii T, Haga S, Tobutake S. Presence of neurofilament protein in Alzheimer’sneurofibrillary tangles (ANF); an immunofluorescent study. Acta Neuropathol1979; 48: 105-12.

29. Cambetti P, Shecket G, Ghetti B, Hirano A, Dahl DJ. Neurofibrillary changes inhuman brain. An immunocytochemical study with a neurofilament antiserum.Neuropathol Exptl Neurol 1983; 42: 69-79.

30. Anderton BH, Breinburg D, Downes MJ, et al. Monoclonal antibodies show thatneurofibrillary tangles and neurofilaments share antigenic determinants. Nature(Lond) 1982; 298: 84-86.

31. Roberts GW, Crow TJ, Polak JM. Location of neuronal tangles in somatostatinneurones in Alzheimer’s disease. Nature (Lond) 1985; 314: 92-94.

32. Yen SH, Gaskin F, Fu SM. Neurofibrillary tangles in senile dementia of theAlzheimer type share an antigenic determinant with intermediate filaments of thevimentin class. Am J Pathol 1983; 113: 373-81.

33. Grundke-Iqbal I, Iqbal K, Quinlan M, Tung YC, Zaidi MS, Wisniewski HM.Microtubule-associated protein tau: a component of Alzheimer paired helicalfilaments. J Biol Chem 1986; 261: 6084-89.

34. Sternberger LA, Sternberger NH. Monoclonal antibodies distinguish phosphorylatedand nonphosphorylated forms of neurofilaments in situ. Proc Natl Acad Sci USA1983; 80: 6126-30.

35. Grundke-Iqbal I, Wang GP, Iqbal K, Tung YC, Wisniewski HM. Alzheimer pairedhelical filaments: Identification of polypeptides with monoclonal antibodies. ActaNeuropathol 1985; 68: 279-83.

LEVODOPA IN RESTLESS LEGS

CHRISTIAN VON SCHEELE

Department of Medicine, Sollefteå Hospital,S-881 04 Sollefteå, Sweden

Summary The effectiveness of levodopa in thetreatment of restless legs was assessed in a

double-blind trial. 20 patients were given levodopa andlactose on alternate days. Treatment was continued untilpatients stated a preference for one of the treatments or wereunable to discriminate between the two. 17 patientspreferred levodopa, none lactose, and 3 were unable todiscriminate. The 17 patients who responded to levodopareported complete relief.

Introduction

THE restless legs syndrome is characterised by discomfortin the legs such as aching, pulling, prickling, and creepingsensations, and sometimes myoclonias. No treatment hasbeen found to be effective.

In the present study levodopa with benserazide wascompared with placebo.

Patients and Methods

We took a group of 24 consecutive patients with the restless legssyndrome. 4 patients were excluded because of alcoholism orsenility. The study group consisted of 12 women (aged 48 to 83years, mean 61 years) and 8 men (aged 10 to 64 years, mean 54years).The optimum dose of levodopa for each patient was titrated

during a pre-trial period of 14 days. Each patient was then providedwith two coded boxes: one contained capsules with levodopa andbenserazide and the other contained capsules with lactose. Theappearance of the two preparations was identical, so the patients andthe assessor were "blind" to the contents of each box. The patientswere instructed to take capsules daily from alternate boxes. Theregimen was continued until patients stated a preference for one ofthe treatments or were unable to discriminate between the two.After all the reports had been received the code was broken.

Results

17 patients stated a preference for levodopa, and none forlactose (highly significant difference, p<0-001). The 17

patients who preferred levodopa reported complete relief,and they were all able to make their choice within 1 week. 3patients reported no relief with either treatment and

consequently were unable to distinguish between the two.This difference was significant (p < 001), and it shows thatmost patients with restless legs can be completely relievedwith levodopa combined with benserazide.

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Discussion

The restless legs syndrome was first described byThomas Willis, and later by Ekbom.1

Usually, the disorder appears in middle age, but

sometimes people in their early teens are affected. The mainsymptom is a creeping or crawling sensation between theknee and ankle.1 2 patients in this study also reporteddiscomfort in the upper limbs. All patients had hadsymptoms for more than 3 years. The symptoms alwaysappear during rest and temporary relief is obtained bymovement; none of the patients was able to attend thecinema.

Clonazepam and carbemazine have been shown to be ofsome benefit,2,3 and iron-treatment, vasodilators, ascorbicacid, aldehyde, and opioids have also been proposed. 3,4pinar5 reported successful treatment of 5 patients withlevodopa and benserazide. In the present study thiscombination of drugs was successful in 17 of 20 patients.The youngest patient (10 years) and the oldest (83 years)preferred a dose of 50 mg, whereas 14 of the other 15 patientstook 100 mg levodopa at bedtime. The exception was a

woman in her 50s who took 200 mg every 4 hours during thenight.

Levodopa is valuable in the treatment of the restless legssyndrome, but the mode of action of the drug is unknown. Itseems likely that dopaminergic pathways are involved. Thisassumption is supported by the fact that akathisia, whichproduces phenothiazine-induced blockage of dopaminergicneurons, seems to be the daytime analogue of the restlesslegs syndrome.

Correspondence should be addressed to C. v-S.

REFERENCES

1. Ekbom KA. Restless legs syndrome. Neurology 1960; 10: 868-73.2. Montplaisir J, Godbout R, Boghen D, DeChamplam J, Young SN, Lapierre G.

Familial restless legs with periodic movements in sleep: electrophysiologic,biochemical and pharmacologic study. Neurology 1985; 35: 130-34.

3. Telstad W, Sorensen O, Larsen S, Lillevold PE, Stensrud P, Nyberg-Hansen R.Treatment of the restless legs syndrome with carbamazepine: a double blind study.Br Med J 1984; 288: 444-46.

4. Trzepacz PT, Violette EJ, Sateia MJ. Response to opioids in three patients withrestless legs syndrome. Am J Psychiatry 1984; 141: 993-94.

5. Akpmar S. Treatment of restless legs syndrome with levodopa plus benserazide. ArchNeurol 1982; 39: 739.

Hypothesis

DOES ANGIOTENSIN-II PROTECT AGAINSTSTROKES?

M. J. BROWN J. BROWN

Clinical Pharmacology Unit, Adderibrooke’s Hospital, Hills Road,Cambridge CB2 2QQ; and Department of Clinical Pharmacology,

Royal Postgraduate Medical School, London W12

Summary In the Medical Research Council trial forthe treatment of mild hypertension,

bendrofluazide showed an unexpected and sizeable benefitcompared with propranolol in the reduction of stroke. It issuggested that this difference reflects the opposing actions ofthese drugs on the renin-angiotensin system. The

hypothesis that angiotensin-II protects the distal smallercerebral vessels, which are the usual site of vessel rupture inintracerebral haemorrhage, indicates that long-term benefitof angiotensin-converting-enzyme inhibitors in thetreatment of hypertension cannot be assumed.

INTRODUCTION

OF the two hypotensive drugs studied in the MedicalResearch Council (MRC) trial for the treatment of mildhypertension’ bendrofluazide was found to be almost threetimes as effective as propranolol in the prevention of strokes;in some groups of patients (eg, male smokers) the differencebetween the drugs was even greater because the beta-blocking drug provided no protection against strokes at all.We consider here the implications of the thiazide versusbeta-blocker result, and propose that the renin-angiotensinsystem (RAS) may have a beneficial role in patients withessential hypertension.The observation that activation of the RAS may be

inversely related to cardiovascular morbidity is not new, 2,3but it has great clinical relevance since the use of

angiotensin-converting-enzyme (ACE) inhibitors is likely to

increase in the aftermath of the MRC trial. ACE inhibitors

provide a treatment for hypertension that is relatively free ofside-effects, but they may not be suitable for long-termtherapy if the release of angiotensin-11 (ANG-11) is essentialfor controlling blood flow to the brain and kidney in the faceof sudden changes in blood pressure.

HYPOTHESIS S

We postulate that the release of ANG-II in the cerebralblood vessel walls plays an important part in the control ofcerebral blood flow. When systemic blood pressure rises theconstriction by ANG-I I of the large cerebral vessels protectsthe distal smaller vessels, which may not otherwisewithstand the raised pressure, and which are the usual site ofvessel rupture in intracerebral haemorrhage.

EVIDENCE

Our hypothesis arises from the results of the MRC trialand from the evidence for a complete renin-angiotensinsystem within the brain. Cerebral blood flow in man is notaltered by changes in the intraluminal concentration ofANG-II (or most other vasoconstrictors, such as

noradrenaline).4,s When these agents are infused

intravenously, the apparent lack of responsiveness is due inpart to the autoregulatory response of the small cerebralresistance vessels to changes in perfusion pressure.4 Closecarotid arterial injection of ANG-11 and noradrenaline doesnot alter blood flow, even though these agents are

vasoconstrictory when applied directly to the surface oflarger cerebral vessels in vitro.s-7 The lack of responsivenessof blood flow to intraluminal ANG-II (or noradrenaline)may also reflect their inability to cross the tight junctionsbetween the vascular endothelial cells of the small cerebralresistance vessels, which comprise the blood-brain barrier.8For this reason, however, ANG-11 could also have a role inthe control of cerebral vascular tone if it can be locallyreleased in these vessels.The idea that there may be local generation of ANG-11

within the arterial wall is not new.9 Studies suggest thatperipheral vascular ANG-11 production may be at least asimportant as conversion of circulating angiotensin I in the