569 PREVENTION OF CORONARY HEART-DISEASE Sm—In July the Department of Health circulated all doctors with the recommendations of a joint working-party of the Royal College of Physicians and the British Cardiac Society on the Prevention of Coronary Heart Disease. This official endorsement is astonishing. The main recommendation was to lower plasma-cholesterol by reducing saturated animal and dairy fat in the diet. In your columns two years ago,Iemphasised the uncertainty about this recommendation, and I am now even more convinced, from the arguments then presented and from further advances, that there can be little benefit on coronary incidence from such measures. The joint report is narrowly based on epidemiological studies and has ignored relevant and direct observational studies of high significance in this important and complex pathological process.
(1) Examination of living coronary arteries by angiography2 shows no difference in the severity of coronary-artery disease between patients with high and those with normal lipid values. Indeed Fuster et al.2 reported that "stepwise discriminant analysis revealed that no combination of the three coronary risk factors (smoking, hypertension and cholesterol) had any influence on the cardiographic patterns".
(2) An American controlled study3 in 834 patients on clofibrate and/or niacin which reduce plasma-cholesterol very significantly showed that these drugs had no beneficial influence coronary mortality.
on
(3) Werko has done a critical analysis. of the Framingham and other reports, finding a number of disturbing defects and discrepancies. He also points out the lack of any linear relationship of cholesterol levels with coronary manifestations in the published charts (figs. 7 and 8) in the Seven Countries study.’ Statistical correlation carries no conviction as a causeand-effect relationship and indeed the correlation is hardly significant if we exclude the figures for the East Finns (see [4] below). Björck,6 having given these matters the most detailed consideration over many years, was also highly sceptical about risk factors. (4) Punsar and Kamoven7 in their careful follow-up have shown that the higher coronary mortality in East Finland is due to the strenuous work of lumberjacks and not to cholesterollevels which were equally high in West Finland where the coronary death-rate is half. Dr Donald Gregg reported to the recent European Congress of Cardiology that when the coronary flow in dogs is reduced to a critical level exercise can precipitate infarction. In your editorial
(Aug. 28, p. 449)
you
comment
that in pa-
tients with atypical E.C.G.S who develop infarcts subsequently serum-cholesterol was not important. Indeed we all have a degree of coronary atheroma after about age 30. It is only the accidental complications that matter.
Many other points in the joint report deserve critical re-examination. It is better to trust to luck than to foster neurosis by pretence that we can save lives by interfering with life habits. Much of the advice is good general advice, but coronary disablement and mortality are unlikely to be changed. The Department of Health to its credit did not recommend the substitution of animal fats by polyunsaturated margarine. 2 Sorth Square, London XW11I
JOHN MCMICHAEL
1. 2.
McMichael, J. Lancet, 1974, i, 1340. Fuster, V., Frye, R. L., Connolly, D. C., Danielson, M. A., Elveback, L. R., Kurland, L. T. Br. Heart. J. 1975, 37, 1250. 3. Coronary Drug Project. J. Am. med. Ass. 1975, 231, 360. 4 Werkö, L. Am. Heart J. 1976, 91, 87. 5. International Co-operative Study on the Epidemiology of Cardiovascular Disease. Circulation, 1970, 42. 6. Björck, G. Contrasting Concepts of Ischæmic Heart Disease. Lilly Lectures
of 1974, Stockholm,
1975.
7. Punsar, S., Karvonen, M. J. in Paavo Nurmi Symposium. Basle, 1975.
UNRECOGNISED MYOCARDIAL INFARCTION
SIR,-You state (Aug. 28, p. 449) that "American and Israeli studies suggest that for every clinical infarct detected there is probably at least one unrecognised one in the same population". The number of unrecognised infarcts is obtained from the discovery Of E.C.G. changes thought to indicate infarction in those without symptoms or with atypical symptoms. This leaves out of account those unrecognised infarcts which do not cause E.c.G. changes. For there is no evidence whatsoever to support the commonly made assertion that all infarcts cause E.c.G. changes. The true figure of unrecognised infarcts is probably many times greater than you suggest. You ask: "Should one take frequent E.c.G.s for vague or suspicious symptoms, particularly in those with known risk factors... ?" The one good reason for taking frequent E.C.G.s-or for doing any other investigations-is to benefit the patient. Not so long ago the man who was thought to have the smallest infarct was put to bed for 6 weeks or so, initially at "absolute rest", and advised to live a restricted life thereafter. His brother who was seen by a doctor who did not do an E.c.G. and diagnosed "indigestion" was fortunate indeed to escape that appalling fate. Today, patients with minor infarcts are not treated so abominably, but even if a man is told no more than that he has had a minor infarct and encouraged to carry on living normally he and his wife and family will at the very least be worried. The taking of routine E.C.G.S on the middle-aged male population, which is so common in America and increasingly common in the U.K., is one of the most fatuous aspects of modem medicine. For a normal 12-lead E.c.G. can be found in someone with actual symptoms of myocardial ischaemia, and the finding of an abnormal E.c.. rarely if ever benefits the patient; it merely causes him anxiety. You end your editorial by urging "an attempt at prevention" of coronary heart-disease (C.H.D.). If the public would give up smoking, exercise vigorously throughout life, and not become obese the incidence of many maladies, including C.H.D., would drop. But all this has nothing to do with the taking of vast numbers of E.c.G.s. Vicarage Hill, Farnham, Surrey GU9 8HJ
6
JOHN W., TODD
ELISA: A REPLACEMENT FOR RADIOIMMUNOASSAYS? on the future of radioimmunoassay of timely. Many your readers, aware of the prominence of R.I.A., yet conscious of much discussion of the development of analogous analytical techniques which do without radioactivity, are probably confused about the future of analytical methods and about the way investment in instrumentation and expertise should be directed. Nevertheless I feel that you misrepresent the situation and point too unequivocally to trends which are by no means certain. Radioimmunoassay revolutionised the measurement of biologically important compounds because it combined the structural specificity of specific antibodies (and of other comparable, biologically derived binding reagents) with the sensitivity of radioactive measurement techniques. It adheres to the saturation-assay principle-i.e., a limited amount of a specific reagent (e.g., antibody) reacts with the substance under test and the extent of reaction of the test substance (some of which is labelled) reflects its concentration. An alternative approach uses similar reagents and measurement techniques though the principle is entirely different: an excess of specific reagent (e.g., antibody) is used and measurement is founded on the extent of reaction of the reagent with the test substance. This usually requires that the reagent itself should be labelled. Typical of this approach is the immunoradiometric assay of Miles and Hales. Each of these analytical principles has advantages and disadvantages with respect to
SIR,-Your editorial
was
the other; however, the
radioimmunoassay probably
became
570 dominant
simply because, at the time of its inception, it was easier to purify and label the substance (e.g., insulin, thyroxine) than the reagent (anti-insulin antibody, thyroxine-binding globulin).
...
Labels other than radioactive isotopes can be used in either approach, but technical problems associated with nonradioactive labels such as enzymes and fluorophors deterred all but the most ardent methodologists. ELISA is one such method, exactly analogous to immunoradiometric assay, in which the specific reagent is labelled with a selected enzyme rather than with radioactivity. In comparing ELISA with R.I.A. it is important to distinguish between attributes of the labelled (or excess) reagent methods of the immunoradiometric genre and attributes of enzyme labels per se. The use of an enzyme label confers no specific analytical advantage. All the substances you referred to can be measured with equal (if not greater) sensitivity and precision, and with equal ease, by immunoradiometric assay. Immunoradiometric assays may ultimately replace many R.I.A.S, but your suggestion that enzyme labelling will replace radioisotopic techniques (particularly in assays demanding highest sensitivity) is much more questionable. In making this prediction you present a distorted picture of the logistic and financial disadvantages of radioactive techniques. For example, a simple but adequate manual radioisotope counter costs about 200; the major cost of conventional counting equipment is associated with the sample-changing and data-recording mechanisms-mechanisms which would be required in any automatic device whatever the signal detection system used. Moreover, the isotopes used for labelling represent a tiny part of the total cost of an assay, and the whole cost of radioactivity measurement (including equipment) is undoubtedly less than that of an enzyme assay technique, bearing in mind the additional chemical manipulations required. Although the radioactive reagents used in R.I.A. are often chemically unstable those used in immunoradiometric techniques are not. Thus, for example, we happily use a single preparation of 1251-labelled anti-rabbit y-globulin for six months or more (in an assay for T.s.H.). Finally, the hazards of radioactivity should not be exaggerated; they are much less (in this context) than those associated with the possible presence of hepatitis virus in samples under test. Enzyme labels entail increased sample manipulation, increased liability to extraneous, non-specific, chemical effects and to technical error, and represent an altogether more vulnerable and difficult end-point determination than the placing of a tube into a radioactive counter. For these reasons enzyme methods have not proved generally successful in the measurement of those substances which, because of their low concentration in biological fluids, demand the highest sensitivity and for which radioimmunoassay methods were originally and spe-
cifically designed. It would be foolish to
predict that radioactive techniques superseded or to suggest that non-radioactive immunological assay methods do not possess certain advantages that may make them logistically preferable in the measurement of certain substances or in certain special situations. But it would be quite wrong for your readers to be stampeded into selling their radioanalytical equipment or to anticipate the dawn of a new age in the measurement of biologically important substances merely in consequence of the birth of ELISA. will
never
be
Department of Nuclear Medicine, Middlesex Hospital Medical School, London W1N 8AA
ROGER EKINS
SIR,-Many readers experienced in laboratory medicine will to accept your prediction (Aug. 21, p. 406): "Enzyme immunoassays are expected to overtake radioimmunoassays within a few years". The time required to establish change in clinical laboratory practice is almost always underestimated. The transition from bioassays to colorimetric be unable
analysis for oestrogens took more than six years. Almost two years ago, another editorial’ stated "we shall see the rapid arplication [of cytochemistry] to the measurement of many hor mones for which radioimmunoassays do not exist or are unsatisfactory". The cytochemical assays referred to are not yet available even at national (special assay service) level. I believe that radioimmunoassay (R.I.A.) will continue as a useful and powerful tool for very many years to come--on account of its own potential which has not yet been fully realised. R.I.A. is not more expensive than enzyme-linked immunosorbent assay (ELISA) or enzyme-modified immunoassay technique (EMIT). In the rich developed world, radioisotopic immuno-type assays have already made a greater contribution to health delivery than has, for example, gas chromatography, Most types of enzyme-linked immunoassay, including ELISA, are not in competition with but are complementary to R.I.A. is well suited
ELISA
as a
positive/negative serological test for
large-scale antigen-antibody screening programmes-especially those of the poor world’s major infectious diseases which desperately need tackling. On the other hand, for the analysis of femtomole (10-15 mol) amounts of steroids, hormones, and so on to aid patient diagnosis and treatment there is only x.i.A. Since the scale of research expansion and application is much greater with R.I.A. than with ELISA, replacement of R.I.A. by ELISA seems unlikely for many years, if at all. Area
Laboratory, King Edward
VII
Hospital,
Windsor, Berkshire
D. WATSON
ISLET-CELL HYPERPLASIA AND SUDDEN INFANT DEATH
SIR,—We wish to present findings on a case of sudden unexdeath in a newborn infant which we believe may be relevant to the wider problem of sudden death in infancy, A female infant of 3360 g weight was born to a 28-year-old Hindu para 1 at 38 weeks’ gestation. The baby required no resuscitation at birth, was breast fed, and seemed well, apart from mild jaundice noted on the third day of life. At 80 h age (6.0 A.M.) the baby was found freshly dead lying face downin her cot, having been observed to be well 1½hpreviously. A coroner’s necropsy performed 3 days after death revealed congestion and oedema of the lungs: other organs including
pected
liver and pancreas appeared normal. Histological study confirmed the presence of congestion and focal alveolar hxmorrhage in the lungs and showed massive fatty infiltration in the liver. The major findings of interest, however, were in the pancreas. An apparent lack of normal islets in routine histological sections of the pancreas prompted further studies using granule stains (Gomori aldehyde fuchsin) and immunocytochemistry. These methods revealed extensive endocrine-cell proliferation with apparent budding off of endocrine cells from the ductule epithelium and widespread infiltration of the acinar tissue by groups and sheets of endocrine cells. The masses of endocrine tissue, which filled the centres of many lobules. superficially resembled normal islets but were characterised b their ill-defined and irregular outline. The extent of endocrine proliferation was only fully revealed by using immunocytochemical techniques. A very large number of beta cells, reacting specifically to antibodies to insulin, was observed in all sections studied, but groups of other cell types reacting to antibodies to glucagon, pancreatic polypeptide, somatostatin, and V.I.P. (vasoactive intestinal polypeptide) were present in all fields Quantitative estimation showed that endocrine tissue occupied 108% of the mean total area of the pancreatic sections. This is within the range (6-3-44-9%) seen in cases of nesidioblastosis2 and well outside that established by Heitz et al.3 for normal infants (1 - 5-3.4%). 1. Br.
med. J. 1974, ii,
128.
2. Polak, J. M., Adrian, T. E., Bryant, M. G., Bloom, S. R., Heitz, P. Pearse, A. G. E. Lancet, 1976, i, 328. 3. Heitz, P. U., Kloppel, G., Hacki, W. H., Polak, J. M., Pearse, A. G. E. Un
published.
(1) Examination of living coronary arteries by angiography2 shows no difference in the severity of coronary-artery disease between patients with high and those with normal lipid values. Indeed Fuster et al.2 reported that "stepwise discriminant analysis revealed that no combination of the three coronary risk factors (smoking, hypertension and cholesterol) had any influence on the cardiographic patterns".
(2) An American controlled study3 in 834 patients on clofibrate and/or niacin which reduce plasma-cholesterol very significantly showed that these drugs had no beneficial influence coronary mortality.
on
(3) Werko has done a critical analysis. of the Framingham and other reports, finding a number of disturbing defects and discrepancies. He also points out the lack of any linear relationship of cholesterol levels with coronary manifestations in the published charts (figs. 7 and 8) in the Seven Countries study.’ Statistical correlation carries no conviction as a causeand-effect relationship and indeed the correlation is hardly significant if we exclude the figures for the East Finns (see [4] below). Björck,6 having given these matters the most detailed consideration over many years, was also highly sceptical about risk factors. (4) Punsar and Kamoven7 in their careful follow-up have shown that the higher coronary mortality in East Finland is due to the strenuous work of lumberjacks and not to cholesterollevels which were equally high in West Finland where the coronary death-rate is half. Dr Donald Gregg reported to the recent European Congress of Cardiology that when the coronary flow in dogs is reduced to a critical level exercise can precipitate infarction. In your editorial
(Aug. 28, p. 449)
you
comment
that in pa-
tients with atypical E.C.G.S who develop infarcts subsequently serum-cholesterol was not important. Indeed we all have a degree of coronary atheroma after about age 30. It is only the accidental complications that matter.
Many other points in the joint report deserve critical re-examination. It is better to trust to luck than to foster neurosis by pretence that we can save lives by interfering with life habits. Much of the advice is good general advice, but coronary disablement and mortality are unlikely to be changed. The Department of Health to its credit did not recommend the substitution of animal fats by polyunsaturated margarine. 2 Sorth Square, London XW11I
JOHN MCMICHAEL
1. 2.
McMichael, J. Lancet, 1974, i, 1340. Fuster, V., Frye, R. L., Connolly, D. C., Danielson, M. A., Elveback, L. R., Kurland, L. T. Br. Heart. J. 1975, 37, 1250. 3. Coronary Drug Project. J. Am. med. Ass. 1975, 231, 360. 4 Werkö, L. Am. Heart J. 1976, 91, 87. 5. International Co-operative Study on the Epidemiology of Cardiovascular Disease. Circulation, 1970, 42. 6. Björck, G. Contrasting Concepts of Ischæmic Heart Disease. Lilly Lectures
of 1974, Stockholm,
1975.
7. Punsar, S., Karvonen, M. J. in Paavo Nurmi Symposium. Basle, 1975.
UNRECOGNISED MYOCARDIAL INFARCTION
SIR,-You state (Aug. 28, p. 449) that "American and Israeli studies suggest that for every clinical infarct detected there is probably at least one unrecognised one in the same population". The number of unrecognised infarcts is obtained from the discovery Of E.C.G. changes thought to indicate infarction in those without symptoms or with atypical symptoms. This leaves out of account those unrecognised infarcts which do not cause E.c.G. changes. For there is no evidence whatsoever to support the commonly made assertion that all infarcts cause E.c.G. changes. The true figure of unrecognised infarcts is probably many times greater than you suggest. You ask: "Should one take frequent E.c.G.s for vague or suspicious symptoms, particularly in those with known risk factors... ?" The one good reason for taking frequent E.C.G.s-or for doing any other investigations-is to benefit the patient. Not so long ago the man who was thought to have the smallest infarct was put to bed for 6 weeks or so, initially at "absolute rest", and advised to live a restricted life thereafter. His brother who was seen by a doctor who did not do an E.c.G. and diagnosed "indigestion" was fortunate indeed to escape that appalling fate. Today, patients with minor infarcts are not treated so abominably, but even if a man is told no more than that he has had a minor infarct and encouraged to carry on living normally he and his wife and family will at the very least be worried. The taking of routine E.C.G.S on the middle-aged male population, which is so common in America and increasingly common in the U.K., is one of the most fatuous aspects of modem medicine. For a normal 12-lead E.c.G. can be found in someone with actual symptoms of myocardial ischaemia, and the finding of an abnormal E.c.. rarely if ever benefits the patient; it merely causes him anxiety. You end your editorial by urging "an attempt at prevention" of coronary heart-disease (C.H.D.). If the public would give up smoking, exercise vigorously throughout life, and not become obese the incidence of many maladies, including C.H.D., would drop. But all this has nothing to do with the taking of vast numbers of E.c.G.s. Vicarage Hill, Farnham, Surrey GU9 8HJ
6
JOHN W., TODD
ELISA: A REPLACEMENT FOR RADIOIMMUNOASSAYS? on the future of radioimmunoassay of timely. Many your readers, aware of the prominence of R.I.A., yet conscious of much discussion of the development of analogous analytical techniques which do without radioactivity, are probably confused about the future of analytical methods and about the way investment in instrumentation and expertise should be directed. Nevertheless I feel that you misrepresent the situation and point too unequivocally to trends which are by no means certain. Radioimmunoassay revolutionised the measurement of biologically important compounds because it combined the structural specificity of specific antibodies (and of other comparable, biologically derived binding reagents) with the sensitivity of radioactive measurement techniques. It adheres to the saturation-assay principle-i.e., a limited amount of a specific reagent (e.g., antibody) reacts with the substance under test and the extent of reaction of the test substance (some of which is labelled) reflects its concentration. An alternative approach uses similar reagents and measurement techniques though the principle is entirely different: an excess of specific reagent (e.g., antibody) is used and measurement is founded on the extent of reaction of the reagent with the test substance. This usually requires that the reagent itself should be labelled. Typical of this approach is the immunoradiometric assay of Miles and Hales. Each of these analytical principles has advantages and disadvantages with respect to
SIR,-Your editorial
was
the other; however, the
radioimmunoassay probably
became
570 dominant
simply because, at the time of its inception, it was easier to purify and label the substance (e.g., insulin, thyroxine) than the reagent (anti-insulin antibody, thyroxine-binding globulin).
...
Labels other than radioactive isotopes can be used in either approach, but technical problems associated with nonradioactive labels such as enzymes and fluorophors deterred all but the most ardent methodologists. ELISA is one such method, exactly analogous to immunoradiometric assay, in which the specific reagent is labelled with a selected enzyme rather than with radioactivity. In comparing ELISA with R.I.A. it is important to distinguish between attributes of the labelled (or excess) reagent methods of the immunoradiometric genre and attributes of enzyme labels per se. The use of an enzyme label confers no specific analytical advantage. All the substances you referred to can be measured with equal (if not greater) sensitivity and precision, and with equal ease, by immunoradiometric assay. Immunoradiometric assays may ultimately replace many R.I.A.S, but your suggestion that enzyme labelling will replace radioisotopic techniques (particularly in assays demanding highest sensitivity) is much more questionable. In making this prediction you present a distorted picture of the logistic and financial disadvantages of radioactive techniques. For example, a simple but adequate manual radioisotope counter costs about 200; the major cost of conventional counting equipment is associated with the sample-changing and data-recording mechanisms-mechanisms which would be required in any automatic device whatever the signal detection system used. Moreover, the isotopes used for labelling represent a tiny part of the total cost of an assay, and the whole cost of radioactivity measurement (including equipment) is undoubtedly less than that of an enzyme assay technique, bearing in mind the additional chemical manipulations required. Although the radioactive reagents used in R.I.A. are often chemically unstable those used in immunoradiometric techniques are not. Thus, for example, we happily use a single preparation of 1251-labelled anti-rabbit y-globulin for six months or more (in an assay for T.s.H.). Finally, the hazards of radioactivity should not be exaggerated; they are much less (in this context) than those associated with the possible presence of hepatitis virus in samples under test. Enzyme labels entail increased sample manipulation, increased liability to extraneous, non-specific, chemical effects and to technical error, and represent an altogether more vulnerable and difficult end-point determination than the placing of a tube into a radioactive counter. For these reasons enzyme methods have not proved generally successful in the measurement of those substances which, because of their low concentration in biological fluids, demand the highest sensitivity and for which radioimmunoassay methods were originally and spe-
cifically designed. It would be foolish to
predict that radioactive techniques superseded or to suggest that non-radioactive immunological assay methods do not possess certain advantages that may make them logistically preferable in the measurement of certain substances or in certain special situations. But it would be quite wrong for your readers to be stampeded into selling their radioanalytical equipment or to anticipate the dawn of a new age in the measurement of biologically important substances merely in consequence of the birth of ELISA. will
never
be
Department of Nuclear Medicine, Middlesex Hospital Medical School, London W1N 8AA
ROGER EKINS
SIR,-Many readers experienced in laboratory medicine will to accept your prediction (Aug. 21, p. 406): "Enzyme immunoassays are expected to overtake radioimmunoassays within a few years". The time required to establish change in clinical laboratory practice is almost always underestimated. The transition from bioassays to colorimetric be unable
analysis for oestrogens took more than six years. Almost two years ago, another editorial’ stated "we shall see the rapid arplication [of cytochemistry] to the measurement of many hor mones for which radioimmunoassays do not exist or are unsatisfactory". The cytochemical assays referred to are not yet available even at national (special assay service) level. I believe that radioimmunoassay (R.I.A.) will continue as a useful and powerful tool for very many years to come--on account of its own potential which has not yet been fully realised. R.I.A. is not more expensive than enzyme-linked immunosorbent assay (ELISA) or enzyme-modified immunoassay technique (EMIT). In the rich developed world, radioisotopic immuno-type assays have already made a greater contribution to health delivery than has, for example, gas chromatography, Most types of enzyme-linked immunoassay, including ELISA, are not in competition with but are complementary to R.I.A. is well suited
ELISA
as a
positive/negative serological test for
large-scale antigen-antibody screening programmes-especially those of the poor world’s major infectious diseases which desperately need tackling. On the other hand, for the analysis of femtomole (10-15 mol) amounts of steroids, hormones, and so on to aid patient diagnosis and treatment there is only x.i.A. Since the scale of research expansion and application is much greater with R.I.A. than with ELISA, replacement of R.I.A. by ELISA seems unlikely for many years, if at all. Area
Laboratory, King Edward
VII
Hospital,
Windsor, Berkshire
D. WATSON
ISLET-CELL HYPERPLASIA AND SUDDEN INFANT DEATH
SIR,—We wish to present findings on a case of sudden unexdeath in a newborn infant which we believe may be relevant to the wider problem of sudden death in infancy, A female infant of 3360 g weight was born to a 28-year-old Hindu para 1 at 38 weeks’ gestation. The baby required no resuscitation at birth, was breast fed, and seemed well, apart from mild jaundice noted on the third day of life. At 80 h age (6.0 A.M.) the baby was found freshly dead lying face downin her cot, having been observed to be well 1½hpreviously. A coroner’s necropsy performed 3 days after death revealed congestion and oedema of the lungs: other organs including
pected
liver and pancreas appeared normal. Histological study confirmed the presence of congestion and focal alveolar hxmorrhage in the lungs and showed massive fatty infiltration in the liver. The major findings of interest, however, were in the pancreas. An apparent lack of normal islets in routine histological sections of the pancreas prompted further studies using granule stains (Gomori aldehyde fuchsin) and immunocytochemistry. These methods revealed extensive endocrine-cell proliferation with apparent budding off of endocrine cells from the ductule epithelium and widespread infiltration of the acinar tissue by groups and sheets of endocrine cells. The masses of endocrine tissue, which filled the centres of many lobules. superficially resembled normal islets but were characterised b their ill-defined and irregular outline. The extent of endocrine proliferation was only fully revealed by using immunocytochemical techniques. A very large number of beta cells, reacting specifically to antibodies to insulin, was observed in all sections studied, but groups of other cell types reacting to antibodies to glucagon, pancreatic polypeptide, somatostatin, and V.I.P. (vasoactive intestinal polypeptide) were present in all fields Quantitative estimation showed that endocrine tissue occupied 108% of the mean total area of the pancreatic sections. This is within the range (6-3-44-9%) seen in cases of nesidioblastosis2 and well outside that established by Heitz et al.3 for normal infants (1 - 5-3.4%). 1. Br.
med. J. 1974, ii,
128.
2. Polak, J. M., Adrian, T. E., Bryant, M. G., Bloom, S. R., Heitz, P. Pearse, A. G. E. Lancet, 1976, i, 328. 3. Heitz, P. U., Kloppel, G., Hacki, W. H., Polak, J. M., Pearse, A. G. E. Un
published.
