742 it is established whether the
who were under One of the authors whom I questioned could not remember. The notion that all the effects of catecholamines on breathing are mediated by way of an enhancement of hypoxic chemoreceptor-reflex drive is now too simple: Neil and O’Regan8 have reported that the efferent fibres in the carotid chemoreceptor nerve trunk are capable of depressing chemoreceptor afferent activity, and that they are themselves strongly activated by adrenaline injected into the cerebral circulation. This new and, to me, puzzling information nevertheless focuses attention once more on the importance of the arterial chemoreceptors in the respiratory responses to catecholamines. It seems to me that the evidence I have outlined provides further support for Dr. White’s original criticisms of the assertion9 that the respiratory effect of noradrenaline is central.
anaesthesia, breathed air
University Laboratory of Physiology, Oxford.
or
patients,
oxygen.
D. J. C. CUNNINGHAM.
EMERGENCY WORK BY GENERAL PRACTITIONERS take SIR,-I exception to the first letter in your issue of Sept. 27 (p. 689) which says: " No general practitioner can undertake a responsibility for emergency work in a general hospital whilst providing a twenty-four-hour service in his own practice ..." With due respect to the consultants whose names are appended, I say that this statement is a load of great nonsense. With the help of loyal and efficient partners I did emergency work plus sessional work as a consultant surgeon, from 1926 to 1965. I think that I can honestly say that no patient had to wait more than half an hour for attention, unless I was out at sea attending casualties in the Walmer lifeboat. Now, when our nearest consultant is at least 15 miles away, there is inevitably more delay. My partner, who is a G.P. anaesthetist, has only to call me to obtain immediate freedom from his practice. Walmer, Kent. JAMES HALL.
L-DOPA FOR PROGRESSIVE SUPRANUCLEAR PALSY SIR,-It is reasonable to try L-dopa in patients with progressive supranuclear palsy. Dr. Wagshul and Dr. Daroff’s report (July 12, p. 105) of improvement in tone and mobility in one of two patients, and Dr. Gilbert and Dr. Feldman’s report (Aug. 30, p. 494) of no benefit in a third are therefore timely, especially since it is difficult to collect large numbers of these patients for a clinical trial. We have recently treated a further patient with L-dopa with no improvement. He is a 56-year-old attorney with the full syndrome described by Steele et al.1o Loss of facial expression was noticed in 1964, and this was followed by progressive rigidity of the neck and trunk muscles, bradykinesia, loss of voluntary vertical gaze, with its preservation to passive head tilting, and preservation of voluntary lateral gaze. Progressive dementia has been documented by psychometric testing (I.Q. 98 in June, 1968, and 68 in June, 1969) but loss of intellectual capacities is patchy. A striking feature is severe dyspraxia: he is unable to copy a simple triangle of sticks from a model within his field 8.
9. 10.
of vision, and he often gets out of bed by standing up and walking off the end. L-dopa dosage was increased to 8 g. daily and maintained at this level for 65 days. There was no improvement in his physical signs, intellectual ability, or motor performance. This accords with Wagshul and Daroff’s first case and Gilbert and Feldman’s case. Like Gilbert and Feldman I believe that the benefits of L-dopa are doubtful in this disease. It will be interesting to learn from Dr. Wagshul and Dr. Daroff whether the improvement in motor function in their second patient is maintained. Department of Neurology, Washington Hospital Center, RAMON JENKINS. Washington, D.C.
ORAL CONTRACEPTIVES AND BLOOD-IRON SIR,-The widely used combined oral contraceptives have no significant effect on blood-haemoglobin, but substantially increase serum-iron and iron-binding capacity.I-3 These changes appear to be established within the first treatment cycle and to be due to increased hepatic synthesis or release of an iron-binding p-globulin. Since combined oral contraceptives contain both a synthetic progestogen and a synthetic oestrogen, we thought it would be worth while to compare the effects, on the various forms of blood iron, of the combined oral contraceptiveMinovlar ’ (which contains 1 mg. norethisterone " acetate and 0-05 mg. ethinyl oestradiol) and a mini-pill ", ’SH 420 c’ (which contains only 0-3 mg. norethisterone acetate with no oestrogen). EFFECTS OF ORAL CONTRACEPTIVES ON BLOOD-IRON
Two women received minovlar while six received SH 420 C. All were free of any obvious disease. Blood-samples were collected by venepuncture after an overnight fast. Several samples were taken from the minovlar women during cycles 2 and 4 of treatment, and from all the SH 420 c group during cycles 1 and 2. Pretreatment samples were obtained from three of the latter group. Haemoglobin was estimated in duplicate by the cyanmethxmoglobin methodserum-iron by the method of Kok and Wildand total iron-binding capacity by the method of Peters.The accompanying table shows that there were considerable increases in serum-iron and ironbinding capacity in both groups of women. These results indicate that the changes in serum-iron are due to changes in serum iron-binding proteins, and that these changes are induced by norethisterone acetate, not by the oestrogen. This conclusion is similar to that of Musa et al.’7 We are grateful to Mr. J. E. N. Kelly for technical assistance and to Dr. D. Pullen for access to her oatients.
Schering Chemicals Ltd., Burgess Hill, Sussex. 1. 2. 3. 4.
Neil, E., O’Regan, R. G. Paper read at a meeting of the Physiological Society in Belfast, Sept. 19, 1969. Adamson, A. R., Grahame-Smith, D. G., Peart, W. S., Starr, M.
5. 6.
Lancet, Aug. 9, 1969, p. 293. Steele, J. C., Richardson, J. C., Olszewski, J. Archs Neurol. 1964, 10, 333.
7.
MICHAEL BRIGGS MAXINE STANIFORD.
Burton, J. L. Lancet, 1967, i, 978. Mardell, M., Zilva, J. F. ibid. 1967, ii, 1323. Zadeh, J. A., Karabus, C. D., Fielding, J. Br. med. J. 1967, iv, 708. Wooton, I. D. P. Mirco-Analysis in Medical Biochemistry; p. 118. London, 1964. Kok, d’A., Wild, F. J. clin. Path. 1960, 13, 241. Peters, T., Giovanniello, T. J., Apt, L., Ross, J. F. J. Lab. clin. Med. 1956, 48, 274. Musa, B. H., Doe, R. P., Seal, U. S. J. clin. Endocr. Metab. 1967, 27, 1463.