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CLINICAL DIFFERENTIATION BETWEEN PRIMARY AND METASTATIC BRAIN TUMOURS
1344 The mean levels of plasma-testosterone reported here are lower than those previously reported (Hudson et al. 1963, Riondel et al. 1963, Kent and Acone 1965) although the values lie within the lower range of male plasmatestosterone obtained by Kent and Acone (1965). It seems improbable that the reason for this is methodological, since notionally the method can only overestimate, rather than underestimate, the plasmatestosterone levels. The low values reported here may stem from the fact that all subjects were admitted to hospital and were sedentary or supine (Dray et al. 1965, Southren et al. 1965). Discussion
Our main finding is that plasma-testosterone levels in and British men are similar. This does not support the simple thesis that the high prevalence of nasopharyngeal cancer in African men and the reversal of the sex ratio is due to an excessive oestrogenic stimulus in the general population at risk. This result is puzzling, in that the results of Clifford and Bulbrook (1966) showing a low excretion of androgen metabolites and a high excretion of urinary oestrogens appeared to support the anthropomorphological findings of Trowell (1948)
Kenyan
and Davies (1949). There are, however, several complicating factors. For example, pronounced feminisation can occur in persons with a male phenotype who have the feminising-testis syndrome. These persons may have normal male levels of testosterone (Deshpande, Wang, Bulbrook, and McMillan 1965). Again, Japanese males have less body hair than European males, but Kobayashi et al. (1966) have reported that there is no difference in the plasmatestosterone levels between Japanese males resident in the United States and American European males. The total urinary neutral 17-oxosteroid excretion, however, was lower in the Japanese group than in the European. This latter difference also existed if correction was made for body size between the two groups. Tissue responsiveness to androgens can be blocked permanently by administration of anti-androgens to pregnant rats, when the males of the litter are born with a syndrome that is very similar to that found in men with feminising testes (Neumann and Elger 1965). Thus, foetal and neonatal hormone abnormalities may determine the future reactivity of a tissue to hormonal stimuli. Another problem already touched upon by Clifford and Bulbrook (1966) is that nasopharyngeal cancer in Kenya shows a preponderance of 4-5 to 1 for males compared with females. On a simple " oestrogenic stimulus " hypothesis the long-term stimulus would have to be assumed to be greater in men than in women. Long periods of lactation in which oestrogen excretion (and possible secretion) were low might partly account for this. Finally, whether testosterone influences the growth and metabolism of the nasopharyngeal epithelium has still to be determined. Testosterone may conceivably act synergisticaily with the oestrogens as it was reported to do in the development of the mammary gland of the
monkey (Speert 1948). The investigation of hormonal influences in nasopharyngeal cancer is obviously an extremely complicated The present findings indicate that further matter. investigations might profitably start with an examination of foetal and neonatal hormonal exposure, with an investigation of the synergistic and antagonistic effects of
various hormones on the nasopharyngeal epithelium, and with measurement of tissue response to the endocrine environment. Above all, direct measurements of the oestrogens in blood are required.
Summary The plasma-testosterone levels in Kenyan and British men do not differ nor are they correlated with age. These findings do not support the view that the high prevalence of nasopharyngeal cancer in African men is due to an excessive cestrogenic stimulus in the general population at risk. We are grateful to Dr. W. U. Gardner and the trustees of the Anna Fuller Fund for their support; Mr. J. W. Smith, laboratory superintendent, Medical Research Laboratory, Nairobi for careful packing and shipping of specimens from Nairobi to London; Mr. Gideon Shadrack and Mr. Indiazi Ephraim (clinical assistants) for their help; and Miss Vicky Amor and Miss Lesley Peacock for their skilled technical assistance. Requests for reprints should be addressed to D.Y.W., Imperial Cancer Research Fund, Lincoln’s Inn Fields, London W.C.2. REFERENCES
Burger, H. G., Kent, J. R., Kellie, A. E. (1964) J. clin. Endocr. 24, 432. Clifford, P., Bulbrook, R. D. (1966) Lancet, i, 1228. Davies, J. N. P. (1949) Br. med. J. ii, 676. Deshpande, N., Wang, D. Y., Bulbrook, R. D., McMillan, M. (1965) Steroids, 6, 437. Dray, F., Reinberg, A., Sebaoun, J. (1965) C.r. Acad. Sci., Paris 261, 573. Hudson, B., Coghlan, J., Dulmanis, A., Wintour, M., Ekkel, I. (1963) Aust. J. exp. Biol. med. Sci. 41, 235. Kent, J. R., Acone, A. B. (1965) Proceedings Second Symposium on Steroid Hormones, Ghent; p. 31. Kobayashi, T., Lobotsky, J., Lloyd, C. W. (1966) J. clin. Endocr. 26, 610. Neumann, F., Elger, W. (1965) Proceedings Second Symposium on Steroid Hormones, Ghent; p. 168. Riondel, A., Tait, J. F., Gut, M., Tait, S. A. S., Joachim, E., Little, B. (1963) J. clin. Endocr. 23, 620. Southren, A. L., Tochimoto, S., Carmody, N. C., Isurugi, K. (1965) ibid. 25, 1441. Speert, H. (1948) Contr. Embryol. 208, 11. Trowell, H. C. (1948) E. Afr. med. J. 25, 311. Wang, D. Y., Bulbrook, R. D., Hayward, J. L. (1966) Eur. J. Cancer 2, 373.
CLINICAL DIFFERENTIATION BETWEEN PRIMARY AND METASTATIC BRAIN TUMOURS M.B.
ARNOLD BARNETT W’srand, F.C.P.S.A., M.R.C.P. REGISTRAR
PAUL MILLAC Cantab., M.R.C.P.
M.B.
M.R.C. CLINICAL RESEARCH ASSOCIATE
From the University Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne 1
EXPERIENCE in many countries has shown an increasing incidence of neoplastic diseases, especially bronchogenic carcinoma. In an appreciable number of these patients cerebral metastasis develops, often before the primary growth has become apparent, and in many the presenting early symptoms and signs suggest a primary cerebral tumour. Great difficulty may be experienced in distinguishing these syndromes from those due to primary intracranial neoplasms. Since neurosurgical investigations are expensive in money and time and not entirely free from risk, we have compared two series of patients with primary and metastatic brain tumours in an endeavour to establish valid criteria for differential diagnosis. Patients 90 patients (63 consecutive patients with proven primary intracranial tumours and 27 with proven metastatic brain tumours) were investigated and treated in the neurological departments either of the Royal Victoria Infirmary or of the
1345 TABLE I-DISTRIBUTION OF CASES
Newcastle General Hospital between 1960 and 1964 (table i). Only adult patients were considered, and male and female
patients
were
analysed together. Results
Table
11 compares the diagnostic features of the two of groups patients. Discussion the Despite frequency of cerebral metastasis, many standard textbooks of neurology give scant consideration to the problem of distinguishing them from primary intracranial tumours. Loss of weight, organic mental symptoms, anorexia, anxmia, raised erythrocyte-sedimentation rate (E.S.R.), and rapid progression of symptoms are generally thought to be characteristic of metastatic tumours (Merritt 1963). As can be seen from table 11 many of these signs and symptoms are found with similar frequency in both groups of patients. Only the actual demonstration of multiple lesions or microscopic examination will differentiate these with certainty. The patients with primary tumours were younger than those with secondary tumours, but there was a wide range and considerable overlap between the groups. Significant loss of weight of a stone or more was seen with almost equal frequency in both groups of patients and is not a reliable indication of disseminated malignancy. Anaemia was infrequent in these patients, and in every case permitted of an alternative explanation. TABLE II-DIAGNOSTIC FEATURES
The patients demonstrated a great variety of signs and symptoms. Focal or major fits were the presenting symptom in 28 of the 63 patients with primary tumours, and had been present in some of them for several years: only 2 of the 27 patients with secondary tumours had fits as the presenting symptom. Papilloedema was found on admission to hospital in half of the patients with primary tumours, whereas only a third of the group with secondary tumours showed papilloedema. 4 patients with secondary tumours had neurological signs which could not be explained on the basis of a single anatomical lesion: this never applied to those with primary tumours. As might be expected, 8 of the patients with secondary tumours were known to have had malignant disease that had been treated with apparent success: 2 patients had been well for over five years before neurological symptoms supervened. 3 of the patients with primary turnours had had previous malignant tumours elsewhere-2 with carcinoma of the prostate, and 1 with epithelioma of the face. In none of these was there evidence of either local Chest radiorecurrence or widespread dissemination. graphs were abnormal in 12 of the metastatic group and in 3 of the group with primary tumours. In several patients, however, the radiological appearances were due to coincidental chest disease, such as bronchiectasis or fibrosis. Unless it is unequivocal, an abnormal chest film should not preclude neurosurgical investigation before surgery is decided upon. Particular attention has been devoted to the E.s.R., which it was hoped would prove a simple and reliable screening test for disseminated malignancy. The results disclosed a wide scatter in both groups of patients, but greatly raised rates of more than 50 mm. in the hour were found only in patients with secondary tumours. These results are similar to those of other workers (Payman 1962, Hass and Harter
1957). Special investigations were occasionally useful in demonstrating multiple lesions. Radiological examination of the skull disclosed abnormal findings in 30% of the patients with primary tumours but in only 1 of the patients with secondary tumours. The abnormal findings included evidence of raised intracranial pressure, abnormal calcification, bone erosion, and pineal shift. The relative infrequency of these changes in patients with secondary tumours may be due to their rapid growth, infrequent calcification, and the failure of multiple deposits to displace midline structures. A normal electroencephalogram (E.E.G.) was found somewhat more often in the group with primary tumours. The E.E.G. abnormalities were of no value in predicting the nature of the tumour. Changes in the cerebrospinal fluid (c.s.F.) were present with equal frequency in both groups of patients and were of little diagnostic help. In this series, malignant cells were never found in the spinal fluid. The majority of these patients underwent either carotid arteriography or pneumoencephalography. On two occasions each of these investigations demonstrated multiple lesions. In the remainder of the patients, these investigations gave no help in recognising the secondary tumours.
Summary In
*Westergren (mm. in first hour).
series of 90 patients, differentiation between primary and secondary intracranial tumours was often extremely difficult. A history of fits and papillcedema on admission to hospital and changes on the skull X-rays were commoner in patients with primary tumours. Abnormal chest X-rays and greatly raised erythrocyte-sedimentation a
1346 rates were
in
helpful
recognising patients
with
secondary
tumours.
We wish to thank Prof. Henry Miller, Dr. J. N. Walton, Mr J. Hankinson, and Mr. L. Lassman for permission to review their
patients. Requests for reprints should
be addressed
to
P. M.
REFERENCES
Hass, W. K., Harter, D. H. (1957) Neurology, 7, 480. Merritt, H. H. (1963) Textbook of Neurology; p. 301. London. Payman, M. A. (1962) Br. J. Cancer, 16, 56.
a new servo-controlled radiant heater (fig. 1) with a standard convector-heated incubator (’ Isolette’ model C86, Air-Shields Inc., Hatboro, Pennsylvania, U.S.A.) operated in two modes : with an external thermostat under manual control; and servo-controlled. Temperatures, oxygen uptake, and acid-base balance were measured in the three units to assess their relative capacity to establish thermally neutral environments.
efficacy of
Methods
Thirty-two sets of measurements were made on twenty-three naked infants ranging in age from 2 to 14 days and with a birthweight ranging from 2-5 to 3-8 kg. The infants were in three thermal environments currently used in newborn nurseries:
A COMPARISON OF INFRA-RED AND CONVECTIVE HEATING FOR
NEWBORN INFANTS HENRY LEVISON MEDICAL RESEARCH COUNCIL OF CANADA RESEARCH FELLOW
LYDIA LINSAO M.D. St. Tomas FELLOW
PAUL R. SWYER
Cantab.,
M.R.C.P.
NEONATAL RESEARCH UNIT
DIRECTOR,
From the Research Institute of the Hospital for Sick Children and the University Department of Pædiatrics, Toronto, Canada
uptake in resting homoeoihermic animals
OXYGEN
the thermal environment and is at its lowest under neutral thermal conditions (Hill 1961). There is evidence that a thermally neutral environment results in lower mortality-rates for newly born infants, particularly if they are sick or premature (Jolly et al. 1962, Buetow and Klein 1964, Day et al. 1964, Oliver 1965). We have shown that oxygen uptake in healthy newborns under thermally neutral conditions is 5-3 ml. per kg. per min. at 12-24 hours and 5-8 ml. per kg. per min. at 9-14 days (Levison and Swyer 1964). Although most modern incubators are convector heated by warm-air recirculation, radiant heat from panels or infra-red lamps has come into use (Agate and Silverman 1963, Oliver 1965). Latterly a new servo-controlled radiant heating device (’ Sierracin ’ cradle warmer, Sierracin Corporation, 903 North Victory Boulevard, Burbank, California) has become commercially available (Rodaway and Oliver 1965, Miller and Oliver 1966).
depends
is hinged to a plastic bassinette and is open to room air at both ends. The average conditions in the air-conditioned room were: temperature 24’2’"C;relative humidity 55-4%,air-flow 230 litres per min. . (2) Nine infants were in an incubator warmed by circulating air at 33.8 0.74 °C. The air temperature was measured with an air temperature thermistor 5 cm. above the baby’s abdominal skin. (3) Nine mfants were in a similar incubator, ambient air temperature controlled at 33-8 1.’08°C by feed-back from an abdominal skin thermistor with a set point of 36.5OC.
cylinder
L.R.C.P.I.
M.B.
(1) Fourteen were under infra-red radiation from a hemicylinder of bilaminar plastic with a transparent metallic electroconductive film between the laminae. Electrodes supplied an A.c. current to the metallic film which then emitted infra-red energy at a wavelength of 8-7 !.L. The heating cycle was controlled by feed-back from an abdominal skin thermistor with a set point of 36.7OC. The hemi-
Readings in the servo-controlled units were taken with the infant lying supine. In the prone position the thermistor on the abdominal skin would be insulated (Oliver 1965).
on
The purpose of
our
investigation
was to
compare the
a, Convective heat, manual thermostat b, Convective heat, servo-controlled
c, Radiant heat, servo- controlled Fig. 2-Comparative body and environmental temperatures
Bars indicate 1 standard deviation of the mean. The ambient temperature in the radiant heater is effectively that of the room
Care was taken to ensure that the infants in the servo-controlled units did not interrupt the servo loop from the abdominal skin by insulation of the abdominal skin thermistor with a change in posture to the prone position (Oliver 1965). We tested the performance of these three units in terms of their effects on various body and environmental temperatures, oxygen uptake, ventilation, and acid-base balance as determined by arterialised capillary blood-samples obtained by pricking the heels of the infants. Temperatures were measured with thermistors (’ Series 400 Thermistors ’, Yellow Springs Instruments Co., Yellow Springs, Ohio). Oxygen uptake and ventilation were continuously measured in a closed-circuit spirometric system (Levison et al. 1965), the infant’s head being enclosed in a pneumatically sealed helmet. The rate of air-flow around this system was 9 litres per min. Carbon dioxide was removed by means of a soda-lime canister, and tests have disclosed no build-up of carbon dioxide within the head helmet. Infants "
Fig.
t-" Infant servo-controlled radiant heater.
The canopy is heated by passage of an electric current through a metallic electro-conductive transpai ent film sandwiched between clear plastic laminates and emits infra-red radiant energy at a wave length of 8-7 . Room air-flow 230 litres per min.;temperature
24.1°C 0.25.
in
three thermal environments.
"
Our main finding is that plasma-testosterone levels in and British men are similar. This does not support the simple thesis that the high prevalence of nasopharyngeal cancer in African men and the reversal of the sex ratio is due to an excessive oestrogenic stimulus in the general population at risk. This result is puzzling, in that the results of Clifford and Bulbrook (1966) showing a low excretion of androgen metabolites and a high excretion of urinary oestrogens appeared to support the anthropomorphological findings of Trowell (1948)
Kenyan
and Davies (1949). There are, however, several complicating factors. For example, pronounced feminisation can occur in persons with a male phenotype who have the feminising-testis syndrome. These persons may have normal male levels of testosterone (Deshpande, Wang, Bulbrook, and McMillan 1965). Again, Japanese males have less body hair than European males, but Kobayashi et al. (1966) have reported that there is no difference in the plasmatestosterone levels between Japanese males resident in the United States and American European males. The total urinary neutral 17-oxosteroid excretion, however, was lower in the Japanese group than in the European. This latter difference also existed if correction was made for body size between the two groups. Tissue responsiveness to androgens can be blocked permanently by administration of anti-androgens to pregnant rats, when the males of the litter are born with a syndrome that is very similar to that found in men with feminising testes (Neumann and Elger 1965). Thus, foetal and neonatal hormone abnormalities may determine the future reactivity of a tissue to hormonal stimuli. Another problem already touched upon by Clifford and Bulbrook (1966) is that nasopharyngeal cancer in Kenya shows a preponderance of 4-5 to 1 for males compared with females. On a simple " oestrogenic stimulus " hypothesis the long-term stimulus would have to be assumed to be greater in men than in women. Long periods of lactation in which oestrogen excretion (and possible secretion) were low might partly account for this. Finally, whether testosterone influences the growth and metabolism of the nasopharyngeal epithelium has still to be determined. Testosterone may conceivably act synergisticaily with the oestrogens as it was reported to do in the development of the mammary gland of the
monkey (Speert 1948). The investigation of hormonal influences in nasopharyngeal cancer is obviously an extremely complicated The present findings indicate that further matter. investigations might profitably start with an examination of foetal and neonatal hormonal exposure, with an investigation of the synergistic and antagonistic effects of
various hormones on the nasopharyngeal epithelium, and with measurement of tissue response to the endocrine environment. Above all, direct measurements of the oestrogens in blood are required.
Summary The plasma-testosterone levels in Kenyan and British men do not differ nor are they correlated with age. These findings do not support the view that the high prevalence of nasopharyngeal cancer in African men is due to an excessive cestrogenic stimulus in the general population at risk. We are grateful to Dr. W. U. Gardner and the trustees of the Anna Fuller Fund for their support; Mr. J. W. Smith, laboratory superintendent, Medical Research Laboratory, Nairobi for careful packing and shipping of specimens from Nairobi to London; Mr. Gideon Shadrack and Mr. Indiazi Ephraim (clinical assistants) for their help; and Miss Vicky Amor and Miss Lesley Peacock for their skilled technical assistance. Requests for reprints should be addressed to D.Y.W., Imperial Cancer Research Fund, Lincoln’s Inn Fields, London W.C.2. REFERENCES
Burger, H. G., Kent, J. R., Kellie, A. E. (1964) J. clin. Endocr. 24, 432. Clifford, P., Bulbrook, R. D. (1966) Lancet, i, 1228. Davies, J. N. P. (1949) Br. med. J. ii, 676. Deshpande, N., Wang, D. Y., Bulbrook, R. D., McMillan, M. (1965) Steroids, 6, 437. Dray, F., Reinberg, A., Sebaoun, J. (1965) C.r. Acad. Sci., Paris 261, 573. Hudson, B., Coghlan, J., Dulmanis, A., Wintour, M., Ekkel, I. (1963) Aust. J. exp. Biol. med. Sci. 41, 235. Kent, J. R., Acone, A. B. (1965) Proceedings Second Symposium on Steroid Hormones, Ghent; p. 31. Kobayashi, T., Lobotsky, J., Lloyd, C. W. (1966) J. clin. Endocr. 26, 610. Neumann, F., Elger, W. (1965) Proceedings Second Symposium on Steroid Hormones, Ghent; p. 168. Riondel, A., Tait, J. F., Gut, M., Tait, S. A. S., Joachim, E., Little, B. (1963) J. clin. Endocr. 23, 620. Southren, A. L., Tochimoto, S., Carmody, N. C., Isurugi, K. (1965) ibid. 25, 1441. Speert, H. (1948) Contr. Embryol. 208, 11. Trowell, H. C. (1948) E. Afr. med. J. 25, 311. Wang, D. Y., Bulbrook, R. D., Hayward, J. L. (1966) Eur. J. Cancer 2, 373.
CLINICAL DIFFERENTIATION BETWEEN PRIMARY AND METASTATIC BRAIN TUMOURS M.B.
ARNOLD BARNETT W’srand, F.C.P.S.A., M.R.C.P. REGISTRAR
PAUL MILLAC Cantab., M.R.C.P.
M.B.
M.R.C. CLINICAL RESEARCH ASSOCIATE
From the University Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne 1
EXPERIENCE in many countries has shown an increasing incidence of neoplastic diseases, especially bronchogenic carcinoma. In an appreciable number of these patients cerebral metastasis develops, often before the primary growth has become apparent, and in many the presenting early symptoms and signs suggest a primary cerebral tumour. Great difficulty may be experienced in distinguishing these syndromes from those due to primary intracranial neoplasms. Since neurosurgical investigations are expensive in money and time and not entirely free from risk, we have compared two series of patients with primary and metastatic brain tumours in an endeavour to establish valid criteria for differential diagnosis. Patients 90 patients (63 consecutive patients with proven primary intracranial tumours and 27 with proven metastatic brain tumours) were investigated and treated in the neurological departments either of the Royal Victoria Infirmary or of the
1345 TABLE I-DISTRIBUTION OF CASES
Newcastle General Hospital between 1960 and 1964 (table i). Only adult patients were considered, and male and female
patients
were
analysed together. Results
Table
11 compares the diagnostic features of the two of groups patients. Discussion the Despite frequency of cerebral metastasis, many standard textbooks of neurology give scant consideration to the problem of distinguishing them from primary intracranial tumours. Loss of weight, organic mental symptoms, anorexia, anxmia, raised erythrocyte-sedimentation rate (E.S.R.), and rapid progression of symptoms are generally thought to be characteristic of metastatic tumours (Merritt 1963). As can be seen from table 11 many of these signs and symptoms are found with similar frequency in both groups of patients. Only the actual demonstration of multiple lesions or microscopic examination will differentiate these with certainty. The patients with primary tumours were younger than those with secondary tumours, but there was a wide range and considerable overlap between the groups. Significant loss of weight of a stone or more was seen with almost equal frequency in both groups of patients and is not a reliable indication of disseminated malignancy. Anaemia was infrequent in these patients, and in every case permitted of an alternative explanation. TABLE II-DIAGNOSTIC FEATURES
The patients demonstrated a great variety of signs and symptoms. Focal or major fits were the presenting symptom in 28 of the 63 patients with primary tumours, and had been present in some of them for several years: only 2 of the 27 patients with secondary tumours had fits as the presenting symptom. Papilloedema was found on admission to hospital in half of the patients with primary tumours, whereas only a third of the group with secondary tumours showed papilloedema. 4 patients with secondary tumours had neurological signs which could not be explained on the basis of a single anatomical lesion: this never applied to those with primary tumours. As might be expected, 8 of the patients with secondary tumours were known to have had malignant disease that had been treated with apparent success: 2 patients had been well for over five years before neurological symptoms supervened. 3 of the patients with primary turnours had had previous malignant tumours elsewhere-2 with carcinoma of the prostate, and 1 with epithelioma of the face. In none of these was there evidence of either local Chest radiorecurrence or widespread dissemination. graphs were abnormal in 12 of the metastatic group and in 3 of the group with primary tumours. In several patients, however, the radiological appearances were due to coincidental chest disease, such as bronchiectasis or fibrosis. Unless it is unequivocal, an abnormal chest film should not preclude neurosurgical investigation before surgery is decided upon. Particular attention has been devoted to the E.s.R., which it was hoped would prove a simple and reliable screening test for disseminated malignancy. The results disclosed a wide scatter in both groups of patients, but greatly raised rates of more than 50 mm. in the hour were found only in patients with secondary tumours. These results are similar to those of other workers (Payman 1962, Hass and Harter
1957). Special investigations were occasionally useful in demonstrating multiple lesions. Radiological examination of the skull disclosed abnormal findings in 30% of the patients with primary tumours but in only 1 of the patients with secondary tumours. The abnormal findings included evidence of raised intracranial pressure, abnormal calcification, bone erosion, and pineal shift. The relative infrequency of these changes in patients with secondary tumours may be due to their rapid growth, infrequent calcification, and the failure of multiple deposits to displace midline structures. A normal electroencephalogram (E.E.G.) was found somewhat more often in the group with primary tumours. The E.E.G. abnormalities were of no value in predicting the nature of the tumour. Changes in the cerebrospinal fluid (c.s.F.) were present with equal frequency in both groups of patients and were of little diagnostic help. In this series, malignant cells were never found in the spinal fluid. The majority of these patients underwent either carotid arteriography or pneumoencephalography. On two occasions each of these investigations demonstrated multiple lesions. In the remainder of the patients, these investigations gave no help in recognising the secondary tumours.
Summary In
*Westergren (mm. in first hour).
series of 90 patients, differentiation between primary and secondary intracranial tumours was often extremely difficult. A history of fits and papillcedema on admission to hospital and changes on the skull X-rays were commoner in patients with primary tumours. Abnormal chest X-rays and greatly raised erythrocyte-sedimentation a
1346 rates were
in
helpful
recognising patients
with
secondary
tumours.
We wish to thank Prof. Henry Miller, Dr. J. N. Walton, Mr J. Hankinson, and Mr. L. Lassman for permission to review their
patients. Requests for reprints should
be addressed
to
P. M.
REFERENCES
Hass, W. K., Harter, D. H. (1957) Neurology, 7, 480. Merritt, H. H. (1963) Textbook of Neurology; p. 301. London. Payman, M. A. (1962) Br. J. Cancer, 16, 56.
a new servo-controlled radiant heater (fig. 1) with a standard convector-heated incubator (’ Isolette’ model C86, Air-Shields Inc., Hatboro, Pennsylvania, U.S.A.) operated in two modes : with an external thermostat under manual control; and servo-controlled. Temperatures, oxygen uptake, and acid-base balance were measured in the three units to assess their relative capacity to establish thermally neutral environments.
efficacy of
Methods
Thirty-two sets of measurements were made on twenty-three naked infants ranging in age from 2 to 14 days and with a birthweight ranging from 2-5 to 3-8 kg. The infants were in three thermal environments currently used in newborn nurseries:
A COMPARISON OF INFRA-RED AND CONVECTIVE HEATING FOR
NEWBORN INFANTS HENRY LEVISON MEDICAL RESEARCH COUNCIL OF CANADA RESEARCH FELLOW
LYDIA LINSAO M.D. St. Tomas FELLOW
PAUL R. SWYER
Cantab.,
M.R.C.P.
NEONATAL RESEARCH UNIT
DIRECTOR,
From the Research Institute of the Hospital for Sick Children and the University Department of Pædiatrics, Toronto, Canada
uptake in resting homoeoihermic animals
OXYGEN
the thermal environment and is at its lowest under neutral thermal conditions (Hill 1961). There is evidence that a thermally neutral environment results in lower mortality-rates for newly born infants, particularly if they are sick or premature (Jolly et al. 1962, Buetow and Klein 1964, Day et al. 1964, Oliver 1965). We have shown that oxygen uptake in healthy newborns under thermally neutral conditions is 5-3 ml. per kg. per min. at 12-24 hours and 5-8 ml. per kg. per min. at 9-14 days (Levison and Swyer 1964). Although most modern incubators are convector heated by warm-air recirculation, radiant heat from panels or infra-red lamps has come into use (Agate and Silverman 1963, Oliver 1965). Latterly a new servo-controlled radiant heating device (’ Sierracin ’ cradle warmer, Sierracin Corporation, 903 North Victory Boulevard, Burbank, California) has become commercially available (Rodaway and Oliver 1965, Miller and Oliver 1966).
depends
is hinged to a plastic bassinette and is open to room air at both ends. The average conditions in the air-conditioned room were: temperature 24’2’"C;relative humidity 55-4%,air-flow 230 litres per min. . (2) Nine infants were in an incubator warmed by circulating air at 33.8 0.74 °C. The air temperature was measured with an air temperature thermistor 5 cm. above the baby’s abdominal skin. (3) Nine mfants were in a similar incubator, ambient air temperature controlled at 33-8 1.’08°C by feed-back from an abdominal skin thermistor with a set point of 36.5OC.
cylinder
L.R.C.P.I.
M.B.
(1) Fourteen were under infra-red radiation from a hemicylinder of bilaminar plastic with a transparent metallic electroconductive film between the laminae. Electrodes supplied an A.c. current to the metallic film which then emitted infra-red energy at a wavelength of 8-7 !.L. The heating cycle was controlled by feed-back from an abdominal skin thermistor with a set point of 36.7OC. The hemi-
Readings in the servo-controlled units were taken with the infant lying supine. In the prone position the thermistor on the abdominal skin would be insulated (Oliver 1965).
on
The purpose of
our
investigation
was to
compare the
a, Convective heat, manual thermostat b, Convective heat, servo-controlled
c, Radiant heat, servo- controlled Fig. 2-Comparative body and environmental temperatures
Bars indicate 1 standard deviation of the mean. The ambient temperature in the radiant heater is effectively that of the room
Care was taken to ensure that the infants in the servo-controlled units did not interrupt the servo loop from the abdominal skin by insulation of the abdominal skin thermistor with a change in posture to the prone position (Oliver 1965). We tested the performance of these three units in terms of their effects on various body and environmental temperatures, oxygen uptake, ventilation, and acid-base balance as determined by arterialised capillary blood-samples obtained by pricking the heels of the infants. Temperatures were measured with thermistors (’ Series 400 Thermistors ’, Yellow Springs Instruments Co., Yellow Springs, Ohio). Oxygen uptake and ventilation were continuously measured in a closed-circuit spirometric system (Levison et al. 1965), the infant’s head being enclosed in a pneumatically sealed helmet. The rate of air-flow around this system was 9 litres per min. Carbon dioxide was removed by means of a soda-lime canister, and tests have disclosed no build-up of carbon dioxide within the head helmet. Infants "
Fig.
t-" Infant servo-controlled radiant heater.
The canopy is heated by passage of an electric current through a metallic electro-conductive transpai ent film sandwiched between clear plastic laminates and emits infra-red radiant energy at a wave length of 8-7 . Room air-flow 230 litres per min.;temperature
24.1°C 0.25.
in
three thermal environments.
"