- Email: [email protected]
OPTICAL SCREENING FOR SCOLIOSIS
585 aminoacids and restricts the
rate
of
There is also good evidence that the glial cell layer forms a second line of resistance, not by providing a physical barrier, but metabolically. For instance, the lipid-soluble molecules ammonia and medium chain length free fatty acids, which are considered to be neurotoxic, readily pass through the endothelial cell membranes. However, they are prevented from reaching the neurons by the astrocytes where they are rapidly metabolised.12,13 Since the astrocytes do not seem to use much glucose,13,14 they do not interfere with energy metabolism of the neurons which rely almost entirely on glucose as a fuel. In summary, passage of substances from blood to brain is controlled by the endothelial cell layer’ which has properties of a single uninterrupted cellular membrane. Molecules which pass this point are then exposed to a layer of astrocytic processes which has the ability to metabolise them selectively, thereby further preventing unrestricted accesss to neurons. Departments of Physiology and Anesthesia, M. S
Hershey Medical Center of Pennsylvania State University, Hershey, Pennsylvania 17033, U.S.A.
SCREENING FOR THYROID DISEASE
glucose metabolism during
hvpoglycaemia.
RICHARD A. HAWKINS ANKE M. MANS JULIEN F. BIEBUYCK
SIR,-Your July 18 editorial (p. 128) notes that doctors may miss abnormal results when presented with masses of figures. In our prospective study of the diagnostic evaluation of outpatients with dementing illnesses, we have seen three patients with hypothyroidism in the past nine months. Old medical records of two patients included a multiphasic screening profile. In both instances, the profile showed biochemical evidence of hypothyroidism which apparently escaped detection within a mass of figures (20 tests in one instance, 12 in the other). This experience supports your assertion that abnormal results are missed in multiphasic screening profiles-much to the disadvantage of our patients. Regardless of the theoretical costs and benefits of screening, if screening results are not interpreted correctly and acted upon, the screening is worthless. We agree that it is easier to interpret abnormalities when there is a clinical reason for ordering a test rather than when the tests are routine in a screening profile. Department of Medicine, University of Washington, Seattle, Washington 98195,
U.S.A.
ERIC B. LARSON BURTON V. REIFLER CONSTANCE CANFIELD
REACTIONS TO DAPSONE OPTICAL SCREENING FOR SCOLIOSIS
SIR,-Your editorial on school screening for soliosis (Aug. 15) emphasised the importance of early diagnosis in scoliosis, but we feel that it. underestimated the potential value of optical screening monitor the progress of the disease. Screening procedures for any disease should, as you state, be sensitive, accurate, and cheap. Optical contour mapping of the. trunk, whether by Moire fringe interferometry or light-projection techniques, fulfils these requirements, and is also rapid and non-I invasive. The Moire technique has been used with success in Japan and Oxford2 to screen for scoliosis, and it proved to be as sensitive and accurate as clinical examination. With the Moire cameras now commercially available the method is very fast (up to 140 patients in an hour). Since the data can be analysed later, expensive medical supervision is not necessary. A permanent graphic record is always obtained, which can provide a baseline for subsequent monitoring of the progress of the deformity. Procedures for monitoring progression of scoliosis once the diagnosis is established should adhere to the same principles as screening. Optical techniques are well suited for this purpose, and avoid the need for repeated X-rays, which is particularly important in the age-group in which scoliosis occurs. We use an alternative approach to monitor the respiration of patients with scoliosis and other chest wall disorders-i.e., "automated light projection", developed from the principles described by Kovats.3,4 This approach allows us to study not only the structural defects associated with these disorders but also the important functional changes that commonly accompany the methods
to
’
deformity. Lung Function Unit, Brompton Hospital, London SW3 6HP
SIR,-Your editorial (July 25, p. 184) prompts me to draw attention to a potentially dangerous situation which has arisen in the dispensing of dapsone by some retail pharmacists. It should go without saying that writing a prescription for dapsone is followed by the dispensing of that drug and that alone, but I know of four recent cases in Newcastle upon Tyne where patients have been given by mistake ’Maloprim’ tablets (dapsone 100 mg and pyrimethamine 12-55 mg). Four different retail pharmacies have been involved and, though the practice is inexcusable, the "explanation" given is that dapsone is difficult to get. Dapsone tablets 100 mg and 50 mg are manufactured by and easily obtainable direct from Cox Pharmaceuticals, Whiddon Valley, Barnstaple, Devon (tel: 0271 75001) or from them through local suppliers. The side-effects of pyrimethamine include megaloblastic anaemia and dapsone may be wrongly blamed for this if the true nature of the tablets is not known. The error in our cases was discovered quite by chance and the practice may be more widespread than we know. Pyrimethamine used for antimalarial prophylaxis is given in a dosage of 25-50 mg weekly and if as much as seven times that dose is given inadvertently, as would happen for example in a patient prescribed 400 mg dapsone daily for dermatitis herpetiformis, serious sideeffects, like those on the bone marrow and nervous system, might arise. Department of Dermatology, Royal Victoria Infirmary, Newcastle upon Tyne NE 1 4LP
SIR,-Your editorial on the adverse reactions to dapsone mentions that
ANDREW J. PEACOCK MICHAEL D. L. MORGAN DAVID M. DENISON
Cooper AJ, McDonald JM, Gelbard AS, Gledhill RF, Duffy TE. The metabolic fate of 13N-labelled ammonia in rat brain. J Biol Chem 1979; 254: 4982-92. 13.Cremer JE, Teal HM, Heath DF, Cavanagh JB. The influence of portocaval anastomosis on the metabolism of labelled octanoate, butyrate and leucine in rat brain. J Neurochem 1977; 28: 215-22 14. Balazs R, Patel AJ, Richter D. Metabolic compartments in the brain: their properties and relation to morphological structures. In: Balazs R, Cremer JE, eds. Metabolic compartmentation in the brain. New York: John Wiley & Sons, 1972:
12.
167-84. 1 Inoue S. Tsuji H, Otsuka Y, Suzuki H, Shinoto A. Moire topography for early detection of scoliosis Fujinon technical information bulletin. Fuji Photo-Optical Co, Japan, 1977 2 Roger RE, Stokes IAF, Harris JD, Frymover JW, Ruiz C. Monitoring adolescent idiopathic scoliosis with Moire fringe photography Engl Med 1979, 8: 119-27. 3 Kovats F, Plethysmographie optique du tronc—étude du cycle ventilatoire maximal. Bull Physio-path Resp 1970; 6: 833-45. 4 Kovats F Morphometric study of breathing movements using a stereometric method. In Proceedings of International Society for Photogrommetry symposium on biostereometrics, 1974; 340-77.
JANET MARKS
suppression is rare. Three cases of agranulocytosis reported in Australian troops in Vietnam in 1969-70’’’ who were taking ’Paludrine’ (chloroguanidine hydrochloride) and dapsone as a prophylactic against drug-resistant Plasmodium falciparum malaria, which was for a time the major military medical problem of the Australian Army in that conflict. There were other cases of dapsone-induced agranulocytosis reported in American soldiers in Vietnam. Dapsone is one of the two antimalarial drugs in ’Maloprim’ and it would be interesting to know if agranulocytosis has occurred in people taking that drug as a prophylactic against drug-resistant P. falciparum infections. marrow
were
Department of Social and Preventive Medicine, Faculty of Medicine, University of Queensland, Herston, Queensland 4006, Australia 1. Stickland
1970;
JF,
Hurdle WDF.
Agranulocytosis probably
B. A. SMITHURST due to
dapsone
Med
J Aust
i 959.
2. Smithurst BA, Robertson I, Naughton MA Dapsone-induced agranulocytosis complicated by gram-negative septicaemia. Med J Aust 1971; i 537-39
rate
of
There is also good evidence that the glial cell layer forms a second line of resistance, not by providing a physical barrier, but metabolically. For instance, the lipid-soluble molecules ammonia and medium chain length free fatty acids, which are considered to be neurotoxic, readily pass through the endothelial cell membranes. However, they are prevented from reaching the neurons by the astrocytes where they are rapidly metabolised.12,13 Since the astrocytes do not seem to use much glucose,13,14 they do not interfere with energy metabolism of the neurons which rely almost entirely on glucose as a fuel. In summary, passage of substances from blood to brain is controlled by the endothelial cell layer’ which has properties of a single uninterrupted cellular membrane. Molecules which pass this point are then exposed to a layer of astrocytic processes which has the ability to metabolise them selectively, thereby further preventing unrestricted accesss to neurons. Departments of Physiology and Anesthesia, M. S
Hershey Medical Center of Pennsylvania State University, Hershey, Pennsylvania 17033, U.S.A.
SCREENING FOR THYROID DISEASE
glucose metabolism during
hvpoglycaemia.
RICHARD A. HAWKINS ANKE M. MANS JULIEN F. BIEBUYCK
SIR,-Your July 18 editorial (p. 128) notes that doctors may miss abnormal results when presented with masses of figures. In our prospective study of the diagnostic evaluation of outpatients with dementing illnesses, we have seen three patients with hypothyroidism in the past nine months. Old medical records of two patients included a multiphasic screening profile. In both instances, the profile showed biochemical evidence of hypothyroidism which apparently escaped detection within a mass of figures (20 tests in one instance, 12 in the other). This experience supports your assertion that abnormal results are missed in multiphasic screening profiles-much to the disadvantage of our patients. Regardless of the theoretical costs and benefits of screening, if screening results are not interpreted correctly and acted upon, the screening is worthless. We agree that it is easier to interpret abnormalities when there is a clinical reason for ordering a test rather than when the tests are routine in a screening profile. Department of Medicine, University of Washington, Seattle, Washington 98195,
U.S.A.
ERIC B. LARSON BURTON V. REIFLER CONSTANCE CANFIELD
REACTIONS TO DAPSONE OPTICAL SCREENING FOR SCOLIOSIS
SIR,-Your editorial on school screening for soliosis (Aug. 15) emphasised the importance of early diagnosis in scoliosis, but we feel that it. underestimated the potential value of optical screening monitor the progress of the disease. Screening procedures for any disease should, as you state, be sensitive, accurate, and cheap. Optical contour mapping of the. trunk, whether by Moire fringe interferometry or light-projection techniques, fulfils these requirements, and is also rapid and non-I invasive. The Moire technique has been used with success in Japan and Oxford2 to screen for scoliosis, and it proved to be as sensitive and accurate as clinical examination. With the Moire cameras now commercially available the method is very fast (up to 140 patients in an hour). Since the data can be analysed later, expensive medical supervision is not necessary. A permanent graphic record is always obtained, which can provide a baseline for subsequent monitoring of the progress of the deformity. Procedures for monitoring progression of scoliosis once the diagnosis is established should adhere to the same principles as screening. Optical techniques are well suited for this purpose, and avoid the need for repeated X-rays, which is particularly important in the age-group in which scoliosis occurs. We use an alternative approach to monitor the respiration of patients with scoliosis and other chest wall disorders-i.e., "automated light projection", developed from the principles described by Kovats.3,4 This approach allows us to study not only the structural defects associated with these disorders but also the important functional changes that commonly accompany the methods
to
’
deformity. Lung Function Unit, Brompton Hospital, London SW3 6HP
SIR,-Your editorial (July 25, p. 184) prompts me to draw attention to a potentially dangerous situation which has arisen in the dispensing of dapsone by some retail pharmacists. It should go without saying that writing a prescription for dapsone is followed by the dispensing of that drug and that alone, but I know of four recent cases in Newcastle upon Tyne where patients have been given by mistake ’Maloprim’ tablets (dapsone 100 mg and pyrimethamine 12-55 mg). Four different retail pharmacies have been involved and, though the practice is inexcusable, the "explanation" given is that dapsone is difficult to get. Dapsone tablets 100 mg and 50 mg are manufactured by and easily obtainable direct from Cox Pharmaceuticals, Whiddon Valley, Barnstaple, Devon (tel: 0271 75001) or from them through local suppliers. The side-effects of pyrimethamine include megaloblastic anaemia and dapsone may be wrongly blamed for this if the true nature of the tablets is not known. The error in our cases was discovered quite by chance and the practice may be more widespread than we know. Pyrimethamine used for antimalarial prophylaxis is given in a dosage of 25-50 mg weekly and if as much as seven times that dose is given inadvertently, as would happen for example in a patient prescribed 400 mg dapsone daily for dermatitis herpetiformis, serious sideeffects, like those on the bone marrow and nervous system, might arise. Department of Dermatology, Royal Victoria Infirmary, Newcastle upon Tyne NE 1 4LP
SIR,-Your editorial on the adverse reactions to dapsone mentions that
ANDREW J. PEACOCK MICHAEL D. L. MORGAN DAVID M. DENISON
Cooper AJ, McDonald JM, Gelbard AS, Gledhill RF, Duffy TE. The metabolic fate of 13N-labelled ammonia in rat brain. J Biol Chem 1979; 254: 4982-92. 13.Cremer JE, Teal HM, Heath DF, Cavanagh JB. The influence of portocaval anastomosis on the metabolism of labelled octanoate, butyrate and leucine in rat brain. J Neurochem 1977; 28: 215-22 14. Balazs R, Patel AJ, Richter D. Metabolic compartments in the brain: their properties and relation to morphological structures. In: Balazs R, Cremer JE, eds. Metabolic compartmentation in the brain. New York: John Wiley & Sons, 1972:
12.
167-84. 1 Inoue S. Tsuji H, Otsuka Y, Suzuki H, Shinoto A. Moire topography for early detection of scoliosis Fujinon technical information bulletin. Fuji Photo-Optical Co, Japan, 1977 2 Roger RE, Stokes IAF, Harris JD, Frymover JW, Ruiz C. Monitoring adolescent idiopathic scoliosis with Moire fringe photography Engl Med 1979, 8: 119-27. 3 Kovats F, Plethysmographie optique du tronc—étude du cycle ventilatoire maximal. Bull Physio-path Resp 1970; 6: 833-45. 4 Kovats F Morphometric study of breathing movements using a stereometric method. In Proceedings of International Society for Photogrommetry symposium on biostereometrics, 1974; 340-77.
JANET MARKS
suppression is rare. Three cases of agranulocytosis reported in Australian troops in Vietnam in 1969-70’’’ who were taking ’Paludrine’ (chloroguanidine hydrochloride) and dapsone as a prophylactic against drug-resistant Plasmodium falciparum malaria, which was for a time the major military medical problem of the Australian Army in that conflict. There were other cases of dapsone-induced agranulocytosis reported in American soldiers in Vietnam. Dapsone is one of the two antimalarial drugs in ’Maloprim’ and it would be interesting to know if agranulocytosis has occurred in people taking that drug as a prophylactic against drug-resistant P. falciparum infections. marrow
were
Department of Social and Preventive Medicine, Faculty of Medicine, University of Queensland, Herston, Queensland 4006, Australia 1. Stickland
1970;
JF,
Hurdle WDF.
Agranulocytosis probably
B. A. SMITHURST due to
dapsone
Med
J Aust
i 959.
2. Smithurst BA, Robertson I, Naughton MA Dapsone-induced agranulocytosis complicated by gram-negative septicaemia. Med J Aust 1971; i 537-39