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A CRITICAL EVALUATION OF THE TRISODIUM-EDETATE TEST FOR HYPOPARATHYROIDISM AFTER THYROIDECTOMY
124
dehydrogenases: alcohol, glutamic acid, and lactic acid. In addition, zinc acts as a co-factor to a number of enzymes including arginase, camosinase, dehydropeptidase, glycylglycine dipeptidase, histidine deaminase, and tripeptidase, as well as oxaloacetic carboxylase and some of the lecithinases and enolases. Evidence accumulated from studies in microorganisms also supports the thesis that zinc promotes synthesis of protein and nucleic acid. Zinc deficiency in Mycobacterium smegmatis, for example, interferes with the synthesis of R.N.A. and thus secondarily inhibits the synthesis of D.N.A. and other proteins. Whether similar pathways are affected in man remains to be shown. Zinc deficiency may be very common in man. A survey by the U.S. Department of Agriculture revealed that soils in 32 of the 50 states of the U.S.A. are zinc deficient. In most of these areas it has become standard practice to treat the soils or crops with zinc for an optimum harvest. Over the past decade, zinc deficiency has been shown to occur so widely among domestic animals that zinc enrichment of feed has become virtually standard practice in the commercial husbandry of cattle, horses, mice, pheasants, poultry, sheep, rats, quail, and trout. Since zinc deficiency is common in the biosphere, it is probably prevalent in man, particularly in times of increased zinc need. Studies in 47 patients with severe burns disclosed a pronounced zinc deficit beginning shortly after the burn and lasting as long as 2-3 months after the injury (Pories and Strain 1966). More recent observations (Pories et al. unpublished) in postoperative patients have shown a striking zincuria with a fall in zinc stores during the early postoperative period. Poor nutrition in patients after a burn or after surgery probably increases negative zinc balance at a time when the tissue needs increase. Further studies are needed to determine the zinc needs of seriously ill patients, particularly during the catabolic phase. In the light of the present evidence, zinc supplementation seems to be indicated for major burns, serious intestinal fistulas, severe infarctions, and other debilitating states. A greater understanding of the biochemical processes in wound healing (Needham 1952) is obviously needed before specific roles can be assigned to zinc. Further studies must take into account the effects of ascorbic acid (Douglas 1963, Gore et al. 1965), cartilage (Prudden and Allen 1965), and collagen formation (Dunphy 1963, Rhoads and Howard 1963). Zinc can be only one of many factors contributing to the vital processes of repair. This research was supported in part by a grant from the Aerospace Medical Division, under approval of the Surgeon General, U.S. Air Force; in part by grant HE 10213, National Institutes of Health, and grant RH 00042, Division of Radiological Health, Bureau of State Services, U.S. Public Health Service; and in part by the Horatio H. Burtt research fund of the University of Rochester. Our findings should not be construed as a statement of official Air Force policy. The zinc capsules were kindly supplied by Smith Kline & French laboratories, 1500 Spring Garden Street, Philadelphia, Pea. 19101.
Requests for reprints should be addressed to W. H. S., department of radiology, School of Medicine and Dentistry, University of Rochester, N.Y., 14620. REFERENCES American Zinc Institute, Inc. 1964 Zinc in Animal Nutrition. New York. Beecher, H. K. (1966 New Engl. J. Med. 274, 1354. Brown, M. A., Thom, J. V., Orth, G. L., Cova, P., Juarez, J. (1964) Archs envir. Hlth, 8, 657. Douglas, D. M. (1963) Wound Healing and Management. Edinburgh. Dunphy, J. E. 1963 New Engl. J. Med. 268, 1367. Gore, I., Tanaka, Y., Fujinami, T., Goodman, M. L. (1965) J. Nutr. 87, 311. Hill, A. B. 1961 Principles of Medical Statistics. New York.
A CRITICAL EVALUATION OF THE TRISODIUM-EDETATE TEST FOR HYPOPARATHYROIDISM AFTER THYROIDECTOMY
J. M. STOWERS M.A., M.B. Cantab.,
M.D.
Harvard, F.R.C.P., F.R.C.P.E.
CONSULTANT PHYSICIAN
WILLIAM MICHIE M.A., M.B. Aberd., F.R.C.S.E. CONSULTANT SURGEON
ABERDEEN ROYAL INFIRMARY
S. C. FRAZER M.B., Ph.D. Glasg., M.C.Path. PROFESSOR OF CHEMICAL
PATHOLOGY, UNIVERSITY OF ABERDEEN
The trisodium edetate (T.S.E.) infusion test for parathyroid hypofunction has been used in 60 patients selected from a large group of postthyroidectomy patients on a basis of clinical or anatomical suspicion of hypoparathyroidism. 39 were considered to have shown a subnormal response to the T.S.E. infusion test and 24 of these, who also had symptoms possibly suggestive of hypoparathyroidism, took part in a doubleblind trial of treatment with calcium gluconate (equivalent to 720 mg. of calcium per day) versus a placebo. The oral calcium supplement was shown to have no significant effect on symptoms or on serum-calcium. The T.S.E. infusion test failed to indicate a need for treatment for hypoparathyroidism. Moreover the test has proved to be non-specific as an index of parathyroid function since in 1 patient a subnormal T.S.E. response reverted to normal when the patient was given maintenance treatment with calciferol. The longer the interval between thyroidectomy and the T.S.E. test the less likely were patients to show any hypocalcæmic symptoms during or after the test.
Summary
Introduction THIS study was undertaken to investigate further whether the non-specific symptoms commonly reported after partial thyroidectomy are in fact attributable to parathyroid insufficiency, as claimed by Davis et al. (1961) and, if so, whether they can be improved by oral calcium supplements. Rose (1963) in an investigation of such patients with symptoms suggestive of hypoparathyroidism, found that patients receiving massive oral calcium supplements fared no better than those receiving placebo tablets DR. PORIES AND OTHERS:
REFERENCES—continued
Mainland, D. (1963) Elementary Medical Statistics. Philadelphia. Miller, W. J., Morton, J. D., Pitts, W. J., Clifton, C. M. (1965) Proc. Soc. exp. Biol. Med. 118, 427. Morrison, F. B. (1941) Feeds and Feeding. Ithaca, N.Y. Needham, A. E. (1952) Regeneration and Wound-Healing. London. Pories, W. J. (1955) M.D. Thesis, University of Rochester. — Henzel, J. H., Strain, W. H. Unpublished. — Schear, E. W., Jordan, D. R., Chase, J., Parkinson, G., Whittaker, R., Strain, W. H., Rob, C. (1966) Surgery, St. Louis, 59, 821. Strain, W. H. (1966) in Zinc Metabolism; chap. 21. Springfield, —
Illinois.
Prasad, A. S., Miale, A., Jr., Farid, J., Sandstead, H. H., Schulert, A. R., Darby, W. J. (1963) Archs intern. Med. 111, 407. Prudden, J. F., Allen, J. (1965) J. Am. med. Ass. 192, 352. Rhoads, J. E., Howard, J. M. (1963) The Chemistry of Trauma. Springfield, Illinois.
Savlov, E. D., Strain, W. H., Huegin, F. (1962) J. surg. Res. 2, 209. Strain, W. H., Dutton, A. M., Heyer, H. B., Pories, W. J., Ramsey, G. H. (1954) University of Rochester Report. Ramsey, G. H. (1953) ibid. Underwood, E. J. (1962) Trace Elements in Human and Animal Nutrition. —
—
—
New York. U.S. Department of Health, Education, and Welfare (1962) Drinking Water Standards. Washington. von Oettingen, W. F. (1958) Poisoning. Philadelphia. Witts, L. J. (1959) Medical Surveys and Clinical Trials. London.
125 in a double-blind trial. We have selected patients to test for hypoparathyroidism on the basis of low serumcalcium levels in the early post-thyroidectomy period or of clinical manifestations, such as paraesthesise or tetany, or the finding of parathyroid tissue in the resected thyroid material. Such patients had a standard trisodium-edetate (T.s.E.) test and, when the result was abnormal, were considered for inclusion in a double-blind trial of oral calcium supplements and placebo. Patients and Methods Parients The patients
were drawn from a group of 651 thyroidectomy in an earlier report (Michie, Stowers, surveyed patients Frazer, and Gunn 1965). 72 (11-1%) had at least one postoperative serum-calcium value below 4-0 mEq. per litre, or paraathesix, or were known to have lost parathyroid tissue at operation. 4 of these were excluded since the diagnosis of hypoparathyroidism was already established on the basis of at least one serum-calcium level below 3-0 mEq. per litre. A further 8 had either left the area or were unwilling to cooperate, leaving 60 for the standard T.S.E. test. 21 of these had what was considered a normal response to the T.S.E. test (twelve and twenty-four hour serum-calcium at or above 4-0 mEq. per litre). For the purpose of the double-blind trial of calcium supplement versus placebo, patients had to satisfy the dual
Double-blind Trial of Calcium Gluconate and Placebo 24 patients were included in a double-blind, cross-over trial of calcium gluconate (3 tablets four times daily, equivalent to 720 mg. of calcium) and of identical-looking placebo tablets containing no calcium. Every patient took both tablets, each for a period of three months. The order in which the tablets were given was dictated by a random schedule unknown to either patient or doctor. A third person handed out the tablets. A standard record form was completed by the patient before the trial, after three months on tablet A (calcium or placebo), and again after three months on tablet B (placebo or calcium). The proforma is reproduced below and was designed to elicit symptoms of both hypothyroidism and hypoparathyroidism:
hypothyroidism was suspected and confirmed by a serum-protein-bound iodine of 35 g. per 100 ml. or less, or by Where
serum-cholesterol of more than 300 mg. per 100 ml., it was criteria of a subnormal response to T.S.E. infusion and the treated before the double-blind trial was started. On this presence of symptoms considered suggestive of hypoparathyroidism such as parssthesias, cramps, lassitude, or depres- basis, 11 of the 24 patients were shown to be hypothyroid. 10 of these had been operated on for thyrotoxicosis. At each visit sion. Of the 39 whose response was abnormal, only 24 were a venous blood-sample was removed, without stasis, for included in the double-blind trial, 15 being excluded because estimation of serum-calcium. of the absence of possibly relevant symptoms. Amongst these 15 were several patients from whom a parathyroid gland had Results been inadvertently removed. This was not surprising for The patient’s own assessments of the two types of it has long been recognised experimentally (Welsh 1898) that tablet were as follows: 5 preferred calcium gluconate, loss of two parathyroid glands need not produce any appreci6 preferred placebo, and 13 were unable to express a able evidence of disturbed function. clear preference for either tablet. A number of record In 24 patients selected for the double-blind trial the interval forms indicated frank deterioration during one or other between thyroidectomy and T.S.E. infusion varied from one to eight years. Before a patient was included in the trial, we took period of treatment, and we have attempted a fuller care that hypothyroidism had been corrected, since some of its analysis of the data (table i). It is noteworthy that no less mental symptoms are similar to those of hypoparathyroidism. than 13 out of 28 reports described " significant " T.S.E. Test Technique improvement or deterioration either on placebo alone or The test used was a modification of that described by Kaiser on both placebo and calcium, while 15 reports suggested and Ponsold (1959) and by Jones and Fourman (1963). 70 mg. that calcium or both calcium and placebo had " signiOf T.S.E. per kg. body-weight was given intravenously in 500 ml. ficant " positive or negative effects. (The 4 extra reports 500 dextrose solution over a period of two hours. 20 ml. of 2% are for 4 patients who said that they improved on one of procaine hydrochloride solution was added to relieve discomfort the trial tablets as compared with their previous state and in the cannulated arm. The patient was given a low-calcium deteriorated on the other.) diet (i.e., without dairy products) for the twenty-four hours Table n demonstrates a tendency for the serumthe test and on the the test. Serum-calcium preceding day of calcium to remain lower postoperatively in thyroidecwere obtained on the before and on the readings evening morning of the infusion and at twelve and twenty-four hours TABLE I-ANALYSIS OF SYMPTOMS SUGGESTIVE OF HYPOPARATHYROIDISM after its completion. Blood-samples were taken without stasis DURING DOUBLE-BLIND TRIAL OF CALCIUM GLUCONATE VERSUS and serum-protein determinations were made to permitt PLACEBO correction of catcium values for variations in protein binding. For each 0-1 g. protein above or below 7-2 g. per 100 ml. 0 035 mEq. per litre was subtracted from or added to the serum-calcium value (Dent 1962). In the absence of established criteria for what constitutes a normal response to the infusion, adjusted serum-calcium values of below 4-0 mEq. per litre were regarded as abnormal at either twelve or twenty-four hours after the beginning of the T.S.E. infusion, this being just TABLE II-SERUM-CALCIUM VALUES DURING DOUBLE-BLIND TRIAL OF CALCIUM GLUCONATE VERSUS PLACEBO outside the lower limit of our normal range for serum-calcium. CJICIUm Estimations Serum-calcium was determined in duplicate by the edeticacd-mration fluorescence-indicator method of Bett and Fraser ’l959 h giving in our hands a normal range of 4-2-4-9 wich a mean normal value of 4-64 mEq. per litre (S.D. 0-17) -;ncorrected for plasma-protein). This figure was obtained from 24 preoperative patients with no disease known to affect trie basa! serum-calcium (Michie, Stowers, Frazer, and Gunn 1965 .
126 TABLE III-RESULTS
OF
HYPOPARATHYROIDISM,
T.S.E. INFUSION BEFORE AND
TEST AFTER
IN
A
PATIENT WITH
TREATMENT
WITH
CALCIFEROL
.
Infusion
t
About 5 g.
stopped after paraesthesiz. T.S.E.
3 g. T.S.E. had been
infused, because
of
severe
infused.
patients than in a group of unoperated patients in hospital, but the difference is not statistically significant. There was no significant change, and certainly no rise, in serum-calcium in subjects after three months on an oral calcium supplement when compared with a placebo containing no calcium. Symptoms such as paraesthesiae and nausea with occasional tetany were noted by 16 of the 24 patients during or immediately after the T.s.E. infusion. The average interval since thyroidectomy in this group was fourteen months. The remaining 8 patients, who did not complain of symptoms during or after the T.S.E. infusion, had had their thyroidectomy an average of thirty-five months previously-the shortest interval was eighteen months. In the evaluation of paraesthesix as possible manifestations of hypoparathyroidism it should be noted that 4 of the patients investigated were known to have cervical spondylosis and 1 proved to have the carpaltunnel syndrome, surgical treatment of which relieved tingling previously attributed to hypoparathyroidism. 8 of the 24 subjects showing a subnormal response to the T.s.E. infusion test had serum-protein-bound-iodine
tomised
of 3-5 ug. per 100 ml. or below and another 3 were considered to be hypothyroid on clinical grounds plus the presence of hypercholesterolaemia in 1 of them. The following case history, indicating an effect of vitamin D on the T.s.E. infusion test, is included because of its importance in relation to our interpretation of the test in terms of parathyroid function.
Female, born 1905. Partial thyroidectomy for thyrotoxicosis in 1939. Recurrence of thyrotoxicosis noted 1947 and second thyroidectomy performed in 1948. Later in 1948 admitted to hospital with delusions and hallucinations; noted to have very brisk tendon jerks. Between 1948 and 1960, she underwent several periods of treatment in mental hospitals for depression: also complained of episodes of dyspncea, dysphagia, and transient fading of the voice. Investigated for dyspeptic and urinary symptoms, with negative results, and thought to be hysterical. In 1962 thyroid-function studies were normal. In 1963 admitted to medical ward with additional symptoms of trembling of hands, numbness of face, and intermittently some difficulty in speaking. The possibility of hypoparawas and confirmed as a result of a thyroidism investigated T.S.E. test (table III). Treatment with calciferol (125 mg. per day) was started with subsequent improvement but not complete resolution of her symptoms. Table III presents T.S.E. test results before and after calciferol treatment. The serumprotein was normal at this time. Discussion al. (1961) stimulated interest in latent hypoparathyroidism when they reported that 20 (24%) of 82 thyroidectomised patients showed a subnormal response to a calcium-deprivation test based on administration of sodium phytate. Though only 2 of these 82 patients had Davis
et
basal plasma-calcium values below normal, the mean value for the group (4-76 mEq. per litre, s.D. 0-23), was lower than that of a carefully selected group of 82 controls (4-86 mEq. per litre, s.D. 0-19). Later, workers from the same unit reported a much smaller incidence of postoperative hypoparathyroidism-22% immediately postoperatively, 6% after three months, and 4% at one year. (Wade et al. 1965). In testing for hypoparathyroidism these workers were then using sodium edetate rather than sodium phytate (Wade et al. 1965). They attributed the lower incidence of hypoparathyroidism to improved surgical technique, claiming that the ligation of the inferior thyroid arteries in the second series helped to avoid damage to the more distal arterial supply to the parathyroids by achieving better haemostasis. This is not in accord with our experience that the percentage of cases exhibiting paraesthesioe and/or tetany remains the same whether one, both, or neither inferior thyroid arteries are ligated (Michie, Stowers, Frazer, and Gunn 1965). The T.s.E. test of parathyroid function has the advantages of convenience and speed as compared with the phytate test, although as a pointer to a need for maintenance treatment with calcium it might conceivably be too sensitive. We chose to measure the serum-calcium at both twelve and twenty-four hours after the end of the infusion, each of these times having been proposed by different groups of workers (Kaiser and Ponsold 1959, Jones and Fourman 1963). King et al. (1965) showed that the rate of rise of the serum-calcium within four hours of the end of the edetate infusion was significantly less in thyroidectomy patients and in cases of known hypoparathyroidism than in control groups. However, the simple interpretation of the edetate test as a guide to the parathyroid response to hypocalcaemia is complicated by our finding of a return to a normal T.S.E. response in a patient known to have hypoparathyroidism, when adequately maintained on vitamin D (table III). A somewhat similar case is reported by King et al. (1965). In interpreting edetate tests it is worth noting too that patients with unoperated thyrotoxicosis tend to have low normal basal serum-calcium, with a correspondingly subnormal level at twelve and twenty-four hours after the end of the infusion (Michie, Stowers, Frazer, and Gunn 1965). In thyrotoxic patients a similar deviation to values suggestive of hypoparathyroidism was reported by Harden et al. (1964) using the urinary-phosphateIt must be admitted also that an excretion index. occasional patient without known parathyroid or thyroid abnormality may respond to the infusion with par2esthesise and cramps and an abnormally slow return of the serum-calcium to normal. Although fairly simple to perform in hospital, the edetate test is not without risk, and must be used with discretion. If a recent serum-calcium has been definitely subnormal the test is unnecessary as well as hazardous. The dose of T.S.E. must be calculated with care and the rate of infusion properly controlled, since accidental overdosage could cause sufficient fall in the plasma-level of ionised calcium to produce cardiac arrest. Even when the infusion is adequately controlled, unpleasant paræsthesiæ and tetany may occur during or immediately after the infusion. In this connection it is interesting to note that the highest incidence of hypocalcsemic symptoms during the test occurred in patients who had had their
thyroidectomy within the previous two years (Michie, Stowers, Frazer, and Gunn 1965). These symptoms
127 URINARY EXCRETION OF FREE NORADRENALINE AND ADRENALINE
included tingling of the mouth, face, hands and feet,
headache, tightness face, numbness around the eyes, nausea, apprehension, and discomfort in the prxcordium, and mild tetany developed in 2 patients. The resistance to the development of such symptoms with increasing passage of time since thyroidectomy is presumably a manifestation of the tendency to adapt eventually to subnormal serum-calcium values, which has been described in animals (Sanderson et al. 1960) and in man (Michie, Stowers, Frazer, and Gunn 1965), but it is ill understood. This or any other test of parathyroid function can find a place in the management of patients only if it is a reliable index of a need for treatment. In the present series we accepted a subnormal response to hypocalcaemia after T.S.E. infusion as presumptive evidence of hypoparathyroidism, which we then proceeded to evaluate further by means of a double-blind trial of calcium supplement containing 720 mg. of calcium per day versus a placebo. It is fairly generally accepted that mild hypoparathyroidism, as manifested by moderate hypocalcaemia, parxsthesix, and, occasionally, tetany can be effectively treated by supplements of dietary calcium without additional vitamin D (Davis et al. 1961), but in our trial no beneficial subjective effect and no demonstrable effect on serum-calcium was found during the treatment period with supplements of calcium. On the basis of our results therefore we cannot claim that post-thyroidectomy " hypoparathyroidism ", indicated by symptoms and a subnormal response to the T.s.E. infusion, has any clinical reality. It also seems desirable to treat with considerable reserve such non-specific symptoms as lassitude and depression as evidence of hypoparathyroidism, unless they are associated with hypocalcaemia and respond in the
FOLLOWING ACUTE MYOCARDIAL INFARCTION C. VALORI BRITISH
M.D. Pisa COUNCIL SCHOLAR*
M. THOMAS M.A., M.D. Cantab., M.R.C.P. MEMBER OF SCIENTIFIC STAFF
J. P. SHILLINGFORD M.D. Harvard, M.D.
Lond., F.R.C.P.
DIRECTOR
From the Medical Research Council’s Cardiovascular Research Unit, Royal Postgraduate Medical School, London. W.12
,
Serial measurements have been made of free noradrenaline and adrenaline in the urine of patients with acute myocardial infarction. The level of excretion of noradrenaline varied from normal values to approximately 800% of the mean normal level, and of adrenaline from normal values to approximately 350% of the mean normal level. Summary
Introduction FEW attempts have been made to evaluate a possible role of the autonomic nervous system in the clinical syndromes which may follow acute myocardial infarction in man. ’Nuzum and Bischoff (1953) found increased amounts of adrenaline in the urine of 2 patients with recent myocardial infarction. Raab and Gigee (1954) were unable to detect abnormal urinary catecholamine excretion in 5 patients with acute myocardial infarction. Gazes et al. (1959), using a fluorimetric method measuring plasma catecholamine concentration, found increased noradrenaline levels in 13 patients with acute myocardial infarction; in 7 of these there was also a significant increase of
specifically to therapy. While accepting that the surgeon must constantly be adrenaline. We report here serial observations of excreted free on the look-out for potentially dangerous parathyroid noradrenaline and adrenaline following myocardial the first at least two during hypofunction, years following infarction in man. thyroidectomy, we are not convinced that the T.S.E. infusion test offers any significant advantage over serial Materials and Methods measurements of serum-calcium, particularly in the group Observations were made on 4 patients (3 men and 1 woman), of patients with non-specific symptoms but little objective 59-66. All had clinical histories typical of acute myocardial evidence of hypoparathyroidism. Although it is our aged infarction with electrocardiographic (E.C.G.) and serum-lacticpractice to study the serum-calcium of our thyroidectomy dehydrogenase changes supporting the diagnosis. 2 patients patients for several years postoperatively, it has been our had had one previous myocardial infarction, 1 had had two. Patients were admitted to the coronary care unit (Shillingford experience that if subnormal serum-calcium values are not found in the first week after thyroidectomy the subsequent and Thomas 1964) at Hammersmith Hospital. Collections of urine were supervised by the nurses in charge. Facilities were development of hypoparathyroidism is most unlikely. We thank the patients for their cooperation in undertaking the double-blind trial of calcium gluconate and placebo. Dr. C. D. Needham kindly allowed us to use the information on his patient published in table in. This work was supported in part by a grant from the Medical Research Council to W. M. and S. C. F. Requests for reprints should be addressed to J. M. S., Medical Outpatient Department, Woolmanhill, Aberdeen. REFERENCES
Bett, I. M., Fraser, G. P. (1959) Clin. Chim. Acta, 4, 346. Davis, R. H., Fourman, P., Smith, J. W. G. (1961) Lancet, ii, 1432. Dent. C. E. (1962) Br. med. J. ii, 1419. Harden, R. M., Harrison, M. T., Alexander, W. D., Nordin, B. E. C.
1964, J. Endocr. 28, 281. Jones, K. H , Fourman, P. (1963) Lancet, ii, 119. Kaiser, W., Ponsold, W. (1959) Klin. Wschr. 37, 1183. King, L. R., Pormoy, R. M., Goldsmith, R. E. (1965) J.
clin. Endocr. Metab.
25, 577
Michie, W., Stowers, J. M., Frazer, S. C., Gunn,
A.
(1965) Br. J. Surg.
52, 503.
Rose, N. (1963) Lancet, ii, 116. Sanderson, P. H., Marshall, F., Wilson, R. E. (1960). J. clin. Invest. 39, 662. Wade, J. S. H., Goodall, P., Deane, L., Dauncey, T. M., Fourman, P. 1965, Br. J. Surg. 52, 497. Welsh, D. A. (1898) J. Path. Bact. 5, 202.
available for continuous electrocardiographic monitoring and the measurement of intravascular and intracardiac pressures. Cardiac output was measured by indicator-dilution technique using the photoelectric earpiece and coomassie-blue dye. Special note was made of the following clinical features: skin appearance and temperature, heart-rate, cardiac rhythm, arterial pressure, jugular venous pressure, presence of atrial and third heart sounds; cardiac size, pulmonary venous hypertension, and pulmonary oedema as assessed by radiology. No patient received quinidine, hydroquinidine, tetracycline, other drugs which might interfere with the determination of catecholamines. None received noradrenaline, isoproterenol, or similar drugs which might increase catecholamine excretion.
or
Chemical Method Urinary excretion of free noradrenaline and adrenaline was determined by the spectrofluorometric method described by Crout (1961). Urine collections were made over a twenty-fourhour period in bottles containing 10 ml. of 6N hydrochloric *
Present address: Istituto
Italy.
Patologia Medica, Policlinico Monteluce, Perugia,
dehydrogenases: alcohol, glutamic acid, and lactic acid. In addition, zinc acts as a co-factor to a number of enzymes including arginase, camosinase, dehydropeptidase, glycylglycine dipeptidase, histidine deaminase, and tripeptidase, as well as oxaloacetic carboxylase and some of the lecithinases and enolases. Evidence accumulated from studies in microorganisms also supports the thesis that zinc promotes synthesis of protein and nucleic acid. Zinc deficiency in Mycobacterium smegmatis, for example, interferes with the synthesis of R.N.A. and thus secondarily inhibits the synthesis of D.N.A. and other proteins. Whether similar pathways are affected in man remains to be shown. Zinc deficiency may be very common in man. A survey by the U.S. Department of Agriculture revealed that soils in 32 of the 50 states of the U.S.A. are zinc deficient. In most of these areas it has become standard practice to treat the soils or crops with zinc for an optimum harvest. Over the past decade, zinc deficiency has been shown to occur so widely among domestic animals that zinc enrichment of feed has become virtually standard practice in the commercial husbandry of cattle, horses, mice, pheasants, poultry, sheep, rats, quail, and trout. Since zinc deficiency is common in the biosphere, it is probably prevalent in man, particularly in times of increased zinc need. Studies in 47 patients with severe burns disclosed a pronounced zinc deficit beginning shortly after the burn and lasting as long as 2-3 months after the injury (Pories and Strain 1966). More recent observations (Pories et al. unpublished) in postoperative patients have shown a striking zincuria with a fall in zinc stores during the early postoperative period. Poor nutrition in patients after a burn or after surgery probably increases negative zinc balance at a time when the tissue needs increase. Further studies are needed to determine the zinc needs of seriously ill patients, particularly during the catabolic phase. In the light of the present evidence, zinc supplementation seems to be indicated for major burns, serious intestinal fistulas, severe infarctions, and other debilitating states. A greater understanding of the biochemical processes in wound healing (Needham 1952) is obviously needed before specific roles can be assigned to zinc. Further studies must take into account the effects of ascorbic acid (Douglas 1963, Gore et al. 1965), cartilage (Prudden and Allen 1965), and collagen formation (Dunphy 1963, Rhoads and Howard 1963). Zinc can be only one of many factors contributing to the vital processes of repair. This research was supported in part by a grant from the Aerospace Medical Division, under approval of the Surgeon General, U.S. Air Force; in part by grant HE 10213, National Institutes of Health, and grant RH 00042, Division of Radiological Health, Bureau of State Services, U.S. Public Health Service; and in part by the Horatio H. Burtt research fund of the University of Rochester. Our findings should not be construed as a statement of official Air Force policy. The zinc capsules were kindly supplied by Smith Kline & French laboratories, 1500 Spring Garden Street, Philadelphia, Pea. 19101.
Requests for reprints should be addressed to W. H. S., department of radiology, School of Medicine and Dentistry, University of Rochester, N.Y., 14620. REFERENCES American Zinc Institute, Inc. 1964 Zinc in Animal Nutrition. New York. Beecher, H. K. (1966 New Engl. J. Med. 274, 1354. Brown, M. A., Thom, J. V., Orth, G. L., Cova, P., Juarez, J. (1964) Archs envir. Hlth, 8, 657. Douglas, D. M. (1963) Wound Healing and Management. Edinburgh. Dunphy, J. E. 1963 New Engl. J. Med. 268, 1367. Gore, I., Tanaka, Y., Fujinami, T., Goodman, M. L. (1965) J. Nutr. 87, 311. Hill, A. B. 1961 Principles of Medical Statistics. New York.
A CRITICAL EVALUATION OF THE TRISODIUM-EDETATE TEST FOR HYPOPARATHYROIDISM AFTER THYROIDECTOMY
J. M. STOWERS M.A., M.B. Cantab.,
M.D.
Harvard, F.R.C.P., F.R.C.P.E.
CONSULTANT PHYSICIAN
WILLIAM MICHIE M.A., M.B. Aberd., F.R.C.S.E. CONSULTANT SURGEON
ABERDEEN ROYAL INFIRMARY
S. C. FRAZER M.B., Ph.D. Glasg., M.C.Path. PROFESSOR OF CHEMICAL
PATHOLOGY, UNIVERSITY OF ABERDEEN
The trisodium edetate (T.S.E.) infusion test for parathyroid hypofunction has been used in 60 patients selected from a large group of postthyroidectomy patients on a basis of clinical or anatomical suspicion of hypoparathyroidism. 39 were considered to have shown a subnormal response to the T.S.E. infusion test and 24 of these, who also had symptoms possibly suggestive of hypoparathyroidism, took part in a doubleblind trial of treatment with calcium gluconate (equivalent to 720 mg. of calcium per day) versus a placebo. The oral calcium supplement was shown to have no significant effect on symptoms or on serum-calcium. The T.S.E. infusion test failed to indicate a need for treatment for hypoparathyroidism. Moreover the test has proved to be non-specific as an index of parathyroid function since in 1 patient a subnormal T.S.E. response reverted to normal when the patient was given maintenance treatment with calciferol. The longer the interval between thyroidectomy and the T.S.E. test the less likely were patients to show any hypocalcæmic symptoms during or after the test.
Summary
Introduction THIS study was undertaken to investigate further whether the non-specific symptoms commonly reported after partial thyroidectomy are in fact attributable to parathyroid insufficiency, as claimed by Davis et al. (1961) and, if so, whether they can be improved by oral calcium supplements. Rose (1963) in an investigation of such patients with symptoms suggestive of hypoparathyroidism, found that patients receiving massive oral calcium supplements fared no better than those receiving placebo tablets DR. PORIES AND OTHERS:
REFERENCES—continued
Mainland, D. (1963) Elementary Medical Statistics. Philadelphia. Miller, W. J., Morton, J. D., Pitts, W. J., Clifton, C. M. (1965) Proc. Soc. exp. Biol. Med. 118, 427. Morrison, F. B. (1941) Feeds and Feeding. Ithaca, N.Y. Needham, A. E. (1952) Regeneration and Wound-Healing. London. Pories, W. J. (1955) M.D. Thesis, University of Rochester. — Henzel, J. H., Strain, W. H. Unpublished. — Schear, E. W., Jordan, D. R., Chase, J., Parkinson, G., Whittaker, R., Strain, W. H., Rob, C. (1966) Surgery, St. Louis, 59, 821. Strain, W. H. (1966) in Zinc Metabolism; chap. 21. Springfield, —
Illinois.
Prasad, A. S., Miale, A., Jr., Farid, J., Sandstead, H. H., Schulert, A. R., Darby, W. J. (1963) Archs intern. Med. 111, 407. Prudden, J. F., Allen, J. (1965) J. Am. med. Ass. 192, 352. Rhoads, J. E., Howard, J. M. (1963) The Chemistry of Trauma. Springfield, Illinois.
Savlov, E. D., Strain, W. H., Huegin, F. (1962) J. surg. Res. 2, 209. Strain, W. H., Dutton, A. M., Heyer, H. B., Pories, W. J., Ramsey, G. H. (1954) University of Rochester Report. Ramsey, G. H. (1953) ibid. Underwood, E. J. (1962) Trace Elements in Human and Animal Nutrition. —
—
—
New York. U.S. Department of Health, Education, and Welfare (1962) Drinking Water Standards. Washington. von Oettingen, W. F. (1958) Poisoning. Philadelphia. Witts, L. J. (1959) Medical Surveys and Clinical Trials. London.
125 in a double-blind trial. We have selected patients to test for hypoparathyroidism on the basis of low serumcalcium levels in the early post-thyroidectomy period or of clinical manifestations, such as paraesthesise or tetany, or the finding of parathyroid tissue in the resected thyroid material. Such patients had a standard trisodium-edetate (T.s.E.) test and, when the result was abnormal, were considered for inclusion in a double-blind trial of oral calcium supplements and placebo. Patients and Methods Parients The patients
were drawn from a group of 651 thyroidectomy in an earlier report (Michie, Stowers, surveyed patients Frazer, and Gunn 1965). 72 (11-1%) had at least one postoperative serum-calcium value below 4-0 mEq. per litre, or paraathesix, or were known to have lost parathyroid tissue at operation. 4 of these were excluded since the diagnosis of hypoparathyroidism was already established on the basis of at least one serum-calcium level below 3-0 mEq. per litre. A further 8 had either left the area or were unwilling to cooperate, leaving 60 for the standard T.S.E. test. 21 of these had what was considered a normal response to the T.S.E. test (twelve and twenty-four hour serum-calcium at or above 4-0 mEq. per litre). For the purpose of the double-blind trial of calcium supplement versus placebo, patients had to satisfy the dual
Double-blind Trial of Calcium Gluconate and Placebo 24 patients were included in a double-blind, cross-over trial of calcium gluconate (3 tablets four times daily, equivalent to 720 mg. of calcium) and of identical-looking placebo tablets containing no calcium. Every patient took both tablets, each for a period of three months. The order in which the tablets were given was dictated by a random schedule unknown to either patient or doctor. A third person handed out the tablets. A standard record form was completed by the patient before the trial, after three months on tablet A (calcium or placebo), and again after three months on tablet B (placebo or calcium). The proforma is reproduced below and was designed to elicit symptoms of both hypothyroidism and hypoparathyroidism:
hypothyroidism was suspected and confirmed by a serum-protein-bound iodine of 35 g. per 100 ml. or less, or by Where
serum-cholesterol of more than 300 mg. per 100 ml., it was criteria of a subnormal response to T.S.E. infusion and the treated before the double-blind trial was started. On this presence of symptoms considered suggestive of hypoparathyroidism such as parssthesias, cramps, lassitude, or depres- basis, 11 of the 24 patients were shown to be hypothyroid. 10 of these had been operated on for thyrotoxicosis. At each visit sion. Of the 39 whose response was abnormal, only 24 were a venous blood-sample was removed, without stasis, for included in the double-blind trial, 15 being excluded because estimation of serum-calcium. of the absence of possibly relevant symptoms. Amongst these 15 were several patients from whom a parathyroid gland had Results been inadvertently removed. This was not surprising for The patient’s own assessments of the two types of it has long been recognised experimentally (Welsh 1898) that tablet were as follows: 5 preferred calcium gluconate, loss of two parathyroid glands need not produce any appreci6 preferred placebo, and 13 were unable to express a able evidence of disturbed function. clear preference for either tablet. A number of record In 24 patients selected for the double-blind trial the interval forms indicated frank deterioration during one or other between thyroidectomy and T.S.E. infusion varied from one to eight years. Before a patient was included in the trial, we took period of treatment, and we have attempted a fuller care that hypothyroidism had been corrected, since some of its analysis of the data (table i). It is noteworthy that no less mental symptoms are similar to those of hypoparathyroidism. than 13 out of 28 reports described " significant " T.S.E. Test Technique improvement or deterioration either on placebo alone or The test used was a modification of that described by Kaiser on both placebo and calcium, while 15 reports suggested and Ponsold (1959) and by Jones and Fourman (1963). 70 mg. that calcium or both calcium and placebo had " signiOf T.S.E. per kg. body-weight was given intravenously in 500 ml. ficant " positive or negative effects. (The 4 extra reports 500 dextrose solution over a period of two hours. 20 ml. of 2% are for 4 patients who said that they improved on one of procaine hydrochloride solution was added to relieve discomfort the trial tablets as compared with their previous state and in the cannulated arm. The patient was given a low-calcium deteriorated on the other.) diet (i.e., without dairy products) for the twenty-four hours Table n demonstrates a tendency for the serumthe test and on the the test. Serum-calcium preceding day of calcium to remain lower postoperatively in thyroidecwere obtained on the before and on the readings evening morning of the infusion and at twelve and twenty-four hours TABLE I-ANALYSIS OF SYMPTOMS SUGGESTIVE OF HYPOPARATHYROIDISM after its completion. Blood-samples were taken without stasis DURING DOUBLE-BLIND TRIAL OF CALCIUM GLUCONATE VERSUS and serum-protein determinations were made to permitt PLACEBO correction of catcium values for variations in protein binding. For each 0-1 g. protein above or below 7-2 g. per 100 ml. 0 035 mEq. per litre was subtracted from or added to the serum-calcium value (Dent 1962). In the absence of established criteria for what constitutes a normal response to the infusion, adjusted serum-calcium values of below 4-0 mEq. per litre were regarded as abnormal at either twelve or twenty-four hours after the beginning of the T.S.E. infusion, this being just TABLE II-SERUM-CALCIUM VALUES DURING DOUBLE-BLIND TRIAL OF CALCIUM GLUCONATE VERSUS PLACEBO outside the lower limit of our normal range for serum-calcium. CJICIUm Estimations Serum-calcium was determined in duplicate by the edeticacd-mration fluorescence-indicator method of Bett and Fraser ’l959 h giving in our hands a normal range of 4-2-4-9 wich a mean normal value of 4-64 mEq. per litre (S.D. 0-17) -;ncorrected for plasma-protein). This figure was obtained from 24 preoperative patients with no disease known to affect trie basa! serum-calcium (Michie, Stowers, Frazer, and Gunn 1965 .
126 TABLE III-RESULTS
OF
HYPOPARATHYROIDISM,
T.S.E. INFUSION BEFORE AND
TEST AFTER
IN
A
PATIENT WITH
TREATMENT
WITH
CALCIFEROL
.
Infusion
t
About 5 g.
stopped after paraesthesiz. T.S.E.
3 g. T.S.E. had been
infused, because
of
severe
infused.
patients than in a group of unoperated patients in hospital, but the difference is not statistically significant. There was no significant change, and certainly no rise, in serum-calcium in subjects after three months on an oral calcium supplement when compared with a placebo containing no calcium. Symptoms such as paraesthesiae and nausea with occasional tetany were noted by 16 of the 24 patients during or immediately after the T.s.E. infusion. The average interval since thyroidectomy in this group was fourteen months. The remaining 8 patients, who did not complain of symptoms during or after the T.S.E. infusion, had had their thyroidectomy an average of thirty-five months previously-the shortest interval was eighteen months. In the evaluation of paraesthesix as possible manifestations of hypoparathyroidism it should be noted that 4 of the patients investigated were known to have cervical spondylosis and 1 proved to have the carpaltunnel syndrome, surgical treatment of which relieved tingling previously attributed to hypoparathyroidism. 8 of the 24 subjects showing a subnormal response to the T.s.E. infusion test had serum-protein-bound-iodine
tomised
of 3-5 ug. per 100 ml. or below and another 3 were considered to be hypothyroid on clinical grounds plus the presence of hypercholesterolaemia in 1 of them. The following case history, indicating an effect of vitamin D on the T.s.E. infusion test, is included because of its importance in relation to our interpretation of the test in terms of parathyroid function.
Female, born 1905. Partial thyroidectomy for thyrotoxicosis in 1939. Recurrence of thyrotoxicosis noted 1947 and second thyroidectomy performed in 1948. Later in 1948 admitted to hospital with delusions and hallucinations; noted to have very brisk tendon jerks. Between 1948 and 1960, she underwent several periods of treatment in mental hospitals for depression: also complained of episodes of dyspncea, dysphagia, and transient fading of the voice. Investigated for dyspeptic and urinary symptoms, with negative results, and thought to be hysterical. In 1962 thyroid-function studies were normal. In 1963 admitted to medical ward with additional symptoms of trembling of hands, numbness of face, and intermittently some difficulty in speaking. The possibility of hypoparawas and confirmed as a result of a thyroidism investigated T.S.E. test (table III). Treatment with calciferol (125 mg. per day) was started with subsequent improvement but not complete resolution of her symptoms. Table III presents T.S.E. test results before and after calciferol treatment. The serumprotein was normal at this time. Discussion al. (1961) stimulated interest in latent hypoparathyroidism when they reported that 20 (24%) of 82 thyroidectomised patients showed a subnormal response to a calcium-deprivation test based on administration of sodium phytate. Though only 2 of these 82 patients had Davis
et
basal plasma-calcium values below normal, the mean value for the group (4-76 mEq. per litre, s.D. 0-23), was lower than that of a carefully selected group of 82 controls (4-86 mEq. per litre, s.D. 0-19). Later, workers from the same unit reported a much smaller incidence of postoperative hypoparathyroidism-22% immediately postoperatively, 6% after three months, and 4% at one year. (Wade et al. 1965). In testing for hypoparathyroidism these workers were then using sodium edetate rather than sodium phytate (Wade et al. 1965). They attributed the lower incidence of hypoparathyroidism to improved surgical technique, claiming that the ligation of the inferior thyroid arteries in the second series helped to avoid damage to the more distal arterial supply to the parathyroids by achieving better haemostasis. This is not in accord with our experience that the percentage of cases exhibiting paraesthesioe and/or tetany remains the same whether one, both, or neither inferior thyroid arteries are ligated (Michie, Stowers, Frazer, and Gunn 1965). The T.s.E. test of parathyroid function has the advantages of convenience and speed as compared with the phytate test, although as a pointer to a need for maintenance treatment with calcium it might conceivably be too sensitive. We chose to measure the serum-calcium at both twelve and twenty-four hours after the end of the infusion, each of these times having been proposed by different groups of workers (Kaiser and Ponsold 1959, Jones and Fourman 1963). King et al. (1965) showed that the rate of rise of the serum-calcium within four hours of the end of the edetate infusion was significantly less in thyroidectomy patients and in cases of known hypoparathyroidism than in control groups. However, the simple interpretation of the edetate test as a guide to the parathyroid response to hypocalcaemia is complicated by our finding of a return to a normal T.S.E. response in a patient known to have hypoparathyroidism, when adequately maintained on vitamin D (table III). A somewhat similar case is reported by King et al. (1965). In interpreting edetate tests it is worth noting too that patients with unoperated thyrotoxicosis tend to have low normal basal serum-calcium, with a correspondingly subnormal level at twelve and twenty-four hours after the end of the infusion (Michie, Stowers, Frazer, and Gunn 1965). In thyrotoxic patients a similar deviation to values suggestive of hypoparathyroidism was reported by Harden et al. (1964) using the urinary-phosphateIt must be admitted also that an excretion index. occasional patient without known parathyroid or thyroid abnormality may respond to the infusion with par2esthesise and cramps and an abnormally slow return of the serum-calcium to normal. Although fairly simple to perform in hospital, the edetate test is not without risk, and must be used with discretion. If a recent serum-calcium has been definitely subnormal the test is unnecessary as well as hazardous. The dose of T.S.E. must be calculated with care and the rate of infusion properly controlled, since accidental overdosage could cause sufficient fall in the plasma-level of ionised calcium to produce cardiac arrest. Even when the infusion is adequately controlled, unpleasant paræsthesiæ and tetany may occur during or immediately after the infusion. In this connection it is interesting to note that the highest incidence of hypocalcsemic symptoms during the test occurred in patients who had had their
thyroidectomy within the previous two years (Michie, Stowers, Frazer, and Gunn 1965). These symptoms
127 URINARY EXCRETION OF FREE NORADRENALINE AND ADRENALINE
included tingling of the mouth, face, hands and feet,
headache, tightness face, numbness around the eyes, nausea, apprehension, and discomfort in the prxcordium, and mild tetany developed in 2 patients. The resistance to the development of such symptoms with increasing passage of time since thyroidectomy is presumably a manifestation of the tendency to adapt eventually to subnormal serum-calcium values, which has been described in animals (Sanderson et al. 1960) and in man (Michie, Stowers, Frazer, and Gunn 1965), but it is ill understood. This or any other test of parathyroid function can find a place in the management of patients only if it is a reliable index of a need for treatment. In the present series we accepted a subnormal response to hypocalcaemia after T.S.E. infusion as presumptive evidence of hypoparathyroidism, which we then proceeded to evaluate further by means of a double-blind trial of calcium supplement containing 720 mg. of calcium per day versus a placebo. It is fairly generally accepted that mild hypoparathyroidism, as manifested by moderate hypocalcaemia, parxsthesix, and, occasionally, tetany can be effectively treated by supplements of dietary calcium without additional vitamin D (Davis et al. 1961), but in our trial no beneficial subjective effect and no demonstrable effect on serum-calcium was found during the treatment period with supplements of calcium. On the basis of our results therefore we cannot claim that post-thyroidectomy " hypoparathyroidism ", indicated by symptoms and a subnormal response to the T.s.E. infusion, has any clinical reality. It also seems desirable to treat with considerable reserve such non-specific symptoms as lassitude and depression as evidence of hypoparathyroidism, unless they are associated with hypocalcaemia and respond in the
FOLLOWING ACUTE MYOCARDIAL INFARCTION C. VALORI BRITISH
M.D. Pisa COUNCIL SCHOLAR*
M. THOMAS M.A., M.D. Cantab., M.R.C.P. MEMBER OF SCIENTIFIC STAFF
J. P. SHILLINGFORD M.D. Harvard, M.D.
Lond., F.R.C.P.
DIRECTOR
From the Medical Research Council’s Cardiovascular Research Unit, Royal Postgraduate Medical School, London. W.12
,
Serial measurements have been made of free noradrenaline and adrenaline in the urine of patients with acute myocardial infarction. The level of excretion of noradrenaline varied from normal values to approximately 800% of the mean normal level, and of adrenaline from normal values to approximately 350% of the mean normal level. Summary
Introduction FEW attempts have been made to evaluate a possible role of the autonomic nervous system in the clinical syndromes which may follow acute myocardial infarction in man. ’Nuzum and Bischoff (1953) found increased amounts of adrenaline in the urine of 2 patients with recent myocardial infarction. Raab and Gigee (1954) were unable to detect abnormal urinary catecholamine excretion in 5 patients with acute myocardial infarction. Gazes et al. (1959), using a fluorimetric method measuring plasma catecholamine concentration, found increased noradrenaline levels in 13 patients with acute myocardial infarction; in 7 of these there was also a significant increase of
specifically to therapy. While accepting that the surgeon must constantly be adrenaline. We report here serial observations of excreted free on the look-out for potentially dangerous parathyroid noradrenaline and adrenaline following myocardial the first at least two during hypofunction, years following infarction in man. thyroidectomy, we are not convinced that the T.S.E. infusion test offers any significant advantage over serial Materials and Methods measurements of serum-calcium, particularly in the group Observations were made on 4 patients (3 men and 1 woman), of patients with non-specific symptoms but little objective 59-66. All had clinical histories typical of acute myocardial evidence of hypoparathyroidism. Although it is our aged infarction with electrocardiographic (E.C.G.) and serum-lacticpractice to study the serum-calcium of our thyroidectomy dehydrogenase changes supporting the diagnosis. 2 patients patients for several years postoperatively, it has been our had had one previous myocardial infarction, 1 had had two. Patients were admitted to the coronary care unit (Shillingford experience that if subnormal serum-calcium values are not found in the first week after thyroidectomy the subsequent and Thomas 1964) at Hammersmith Hospital. Collections of urine were supervised by the nurses in charge. Facilities were development of hypoparathyroidism is most unlikely. We thank the patients for their cooperation in undertaking the double-blind trial of calcium gluconate and placebo. Dr. C. D. Needham kindly allowed us to use the information on his patient published in table in. This work was supported in part by a grant from the Medical Research Council to W. M. and S. C. F. Requests for reprints should be addressed to J. M. S., Medical Outpatient Department, Woolmanhill, Aberdeen. REFERENCES
Bett, I. M., Fraser, G. P. (1959) Clin. Chim. Acta, 4, 346. Davis, R. H., Fourman, P., Smith, J. W. G. (1961) Lancet, ii, 1432. Dent. C. E. (1962) Br. med. J. ii, 1419. Harden, R. M., Harrison, M. T., Alexander, W. D., Nordin, B. E. C.
1964, J. Endocr. 28, 281. Jones, K. H , Fourman, P. (1963) Lancet, ii, 119. Kaiser, W., Ponsold, W. (1959) Klin. Wschr. 37, 1183. King, L. R., Pormoy, R. M., Goldsmith, R. E. (1965) J.
clin. Endocr. Metab.
25, 577
Michie, W., Stowers, J. M., Frazer, S. C., Gunn,
A.
(1965) Br. J. Surg.
52, 503.
Rose, N. (1963) Lancet, ii, 116. Sanderson, P. H., Marshall, F., Wilson, R. E. (1960). J. clin. Invest. 39, 662. Wade, J. S. H., Goodall, P., Deane, L., Dauncey, T. M., Fourman, P. 1965, Br. J. Surg. 52, 497. Welsh, D. A. (1898) J. Path. Bact. 5, 202.
available for continuous electrocardiographic monitoring and the measurement of intravascular and intracardiac pressures. Cardiac output was measured by indicator-dilution technique using the photoelectric earpiece and coomassie-blue dye. Special note was made of the following clinical features: skin appearance and temperature, heart-rate, cardiac rhythm, arterial pressure, jugular venous pressure, presence of atrial and third heart sounds; cardiac size, pulmonary venous hypertension, and pulmonary oedema as assessed by radiology. No patient received quinidine, hydroquinidine, tetracycline, other drugs which might interfere with the determination of catecholamines. None received noradrenaline, isoproterenol, or similar drugs which might increase catecholamine excretion.
or
Chemical Method Urinary excretion of free noradrenaline and adrenaline was determined by the spectrofluorometric method described by Crout (1961). Urine collections were made over a twenty-fourhour period in bottles containing 10 ml. of 6N hydrochloric *
Present address: Istituto
Italy.
Patologia Medica, Policlinico Monteluce, Perugia,