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MYALGIA AND BIRD-KEEPING
96
patients with well-documented polymalgia rheumatica as opposed to vague muscle pain. They lead us to doubt whether there is really any association between bird contact
Letters to the Editor
and oolvmvalsia.
SEX RATIO IN PHENYLKETONURIA SiR,-In view of the altered sex ratio among infants included in the Collaborative Study ofChildren Treated for Phenylketonuria (P.K.u.) 1,2’ a group of individuals concerned with the clinical and laboratory aspects of screening for P.K.U. met on June 25-26, 1970, under the auspices of the Maternal and Child Health Service, H. E. W., in Los Angeles, to discuss the implications of these findings upon screening programmes for P.K.u. Previously unreported data were presented from several screening programmes. Although there was a trend towards an excess of males in several studies, none reached statistical significance. Of the 13 patients with typical P.K.u. who were not identified by the initial screening test for P.K.u., 10 were female; while these numbers remain small, there may be a greater tendency to miss the diagnosis of P.K.u. in females. It was the consensus that although very few cases of typical P.K.u. are being missed, physicians still need to do a blood-test for phenylalanine to rule out P.K.u. and hyperphenylalaninaemic variants in children with mental retardation or other neurological signs. Attention was directed to the disproportion of 60 males to 30 females among the cases included in the collaborative study for P.K.u. (p < 0002). It was suggested that the biochemical criteria for inclusion in the study were responsible, either for the exclusion of some females with typical P.K.u., or for the inclusion of some males who did not have typical P.K.u. Although a concerted effort was made to differentiate P.K.u. from its variants, it is still difficult to distinguish between these conditions because the biochemical changes may be age and sex dependent. Phenylalanine loading tests should be repeated beyond the first year to ascertain the accuracy of diagnosis. It was the unanimous opinion that the evidence presented does not suggest the need for any modification of the current screening programme for P.K.u. in the United States; rather it should be continued and encouraged. A summary of the proceedings of the conference will be published elsewhere.3 Loyola University, Stritch School of Medicine, Maywood, Illinois. Division of Child Development, Children’s Hospital of Los Angeles Los Angeles, California. Kinsman Laboratory, University of British Columbia, Vancouver British Columbia.
DAVID Y. Y. HSIA.
JAMES DOBSON RICHARD KOCH. LOUIS I. WOOLF.
MYALGIA AND BIRD-KEEPING SIR,-We have noted with interest two letters reporting an association between bird-keeping and polymyalgia rheumatica.4,5 We have conducted a survey of 40 consecutive patients attending a polymyalgia re-examination clinic at this hospital. Of these 40, whose average age was 70 years, 36 (90%) denied ever having had birds in the
house. Only 4 patients kept budgerigars as petsprobably no more than would be expected in the general population, since budgerigars (" paraquets in the U.S.A.) "
are now
said
to
be the commonest domestic pets in this
country. Our figures, though based 1. 2. 3. 4. 5.
on a
small
sample,
were
from
Dobson, J., Williamson, M. New Engl. J. Med. 1970, 282, 1104. Hsia, D. Y. Y., Dobson, J. Lancet, 1970, i, 905. Koch, R., Dobson, J., Hsia, D. Y. Y., Woolf, L. I. Unpublished. Fessel, W. J. Lancet, 1969, ii, 1249. Fessel, W. J., Ilkin, J. S. ibid. 1970, i, 1403.
Royal National Hospital for Rheumatic Diseases, Bath.
E. ORNILLA A. J. SWANNELL A. ST. J. DIXON.
MNEMONIC FOR REPORTING BACTERIOCIN AND BACTERIOPHAGE TYPES SIR, The nomenclature used in reporting bacteriocin and bacteriophage types has been both complicated and confusing. In the phage typing of Staphylococcus aureus we must contend with such lengthy representations as phage type 6/7/29/42B/42E/44A/47/52/52A/53/54/75/77/80/81/ 83/UC18. In the Gillies and Govan1 scheme for typing Pseudomonas pyocyanea by pyocin production, less than 20% of the 256 possible pyocin patterns have been assigned a type designation; and, unfortunately, there is no systematic way to assign types to newly discovered pyocinproduction patterns because the assignment of types to patterns has not followed any established rules. During the search for a better method to report bacteriocin and bacteriophage patterns, a mnemonic evolved which has greatly simplified the reporting of our typing results. Each of the tests is assigned a number from 1 to N where N is the number of tests employed. For example, in typing by bacteriocin production, the reaction against indicator strain 1 is designated test 1, the reaction against indicator strain 2 is designated test 2, and so on, until all tests are defined. The results of the first three tests are then assigned a number, as determined from the following mnemonic.
Each of the subsequent data triplets is assigned its proper number in a similar fashion. Thus, a test strain which has a bacteriocin production pattern (+—— —+— —++ +—+ ——— —+—) would be, by definition, type 564 386. If the number of tests is not evenly divisible by three, a second (-I- - =A,+- = B, — + =C,-- = D) and third (+ = E, - = F) mnemonic can be used to represent those results remaining after division into triplets. Each of the 2N possible patterns is automatically assigned a type designation according to these simple rules. Although this representation probably will not replace those already established by usage, it is hoped that it will be utilised as new typing systems are devised. Environmental Services Branch, Division of Research Services, National Institutes of Health,
Bethesda, Maryland 20014.
J. J. FARMER, III.
DIAGNOSIS OF PNEUMOCYSTIS CARINII INFECTION SiR,-Dr. Meuwissen and his colleagues2 state that the finding of antibody to Pneumocystis carinii in contacts of a patient can be used as corroborative evidence for infection in the patient. They thereby imply, firstly, that subclinical infection is spread by person-to-person contact and, secondly, that the presence of antibody to Pn. carinii in a healthy person indicates recent infection. Neither of these two possibilities has been suggested elsewhere, owing to the 1. 2.
Gillies, R. R., Govan, J. R. W. J. Path. Bact. 1966, 91, 339. Meuwissen, H. J., Brzosko, W. J., Nowoslawski, A., Good, Lancet, 1970, i, 1124.
R. A.
patients with well-documented polymalgia rheumatica as opposed to vague muscle pain. They lead us to doubt whether there is really any association between bird contact
Letters to the Editor
and oolvmvalsia.
SEX RATIO IN PHENYLKETONURIA SiR,-In view of the altered sex ratio among infants included in the Collaborative Study ofChildren Treated for Phenylketonuria (P.K.u.) 1,2’ a group of individuals concerned with the clinical and laboratory aspects of screening for P.K.U. met on June 25-26, 1970, under the auspices of the Maternal and Child Health Service, H. E. W., in Los Angeles, to discuss the implications of these findings upon screening programmes for P.K.u. Previously unreported data were presented from several screening programmes. Although there was a trend towards an excess of males in several studies, none reached statistical significance. Of the 13 patients with typical P.K.u. who were not identified by the initial screening test for P.K.u., 10 were female; while these numbers remain small, there may be a greater tendency to miss the diagnosis of P.K.u. in females. It was the consensus that although very few cases of typical P.K.u. are being missed, physicians still need to do a blood-test for phenylalanine to rule out P.K.u. and hyperphenylalaninaemic variants in children with mental retardation or other neurological signs. Attention was directed to the disproportion of 60 males to 30 females among the cases included in the collaborative study for P.K.u. (p < 0002). It was suggested that the biochemical criteria for inclusion in the study were responsible, either for the exclusion of some females with typical P.K.u., or for the inclusion of some males who did not have typical P.K.u. Although a concerted effort was made to differentiate P.K.u. from its variants, it is still difficult to distinguish between these conditions because the biochemical changes may be age and sex dependent. Phenylalanine loading tests should be repeated beyond the first year to ascertain the accuracy of diagnosis. It was the unanimous opinion that the evidence presented does not suggest the need for any modification of the current screening programme for P.K.u. in the United States; rather it should be continued and encouraged. A summary of the proceedings of the conference will be published elsewhere.3 Loyola University, Stritch School of Medicine, Maywood, Illinois. Division of Child Development, Children’s Hospital of Los Angeles Los Angeles, California. Kinsman Laboratory, University of British Columbia, Vancouver British Columbia.
DAVID Y. Y. HSIA.
JAMES DOBSON RICHARD KOCH. LOUIS I. WOOLF.
MYALGIA AND BIRD-KEEPING SIR,-We have noted with interest two letters reporting an association between bird-keeping and polymyalgia rheumatica.4,5 We have conducted a survey of 40 consecutive patients attending a polymyalgia re-examination clinic at this hospital. Of these 40, whose average age was 70 years, 36 (90%) denied ever having had birds in the
house. Only 4 patients kept budgerigars as petsprobably no more than would be expected in the general population, since budgerigars (" paraquets in the U.S.A.) "
are now
said
to
be the commonest domestic pets in this
country. Our figures, though based 1. 2. 3. 4. 5.
on a
small
sample,
were
from
Dobson, J., Williamson, M. New Engl. J. Med. 1970, 282, 1104. Hsia, D. Y. Y., Dobson, J. Lancet, 1970, i, 905. Koch, R., Dobson, J., Hsia, D. Y. Y., Woolf, L. I. Unpublished. Fessel, W. J. Lancet, 1969, ii, 1249. Fessel, W. J., Ilkin, J. S. ibid. 1970, i, 1403.
Royal National Hospital for Rheumatic Diseases, Bath.
E. ORNILLA A. J. SWANNELL A. ST. J. DIXON.
MNEMONIC FOR REPORTING BACTERIOCIN AND BACTERIOPHAGE TYPES SIR, The nomenclature used in reporting bacteriocin and bacteriophage types has been both complicated and confusing. In the phage typing of Staphylococcus aureus we must contend with such lengthy representations as phage type 6/7/29/42B/42E/44A/47/52/52A/53/54/75/77/80/81/ 83/UC18. In the Gillies and Govan1 scheme for typing Pseudomonas pyocyanea by pyocin production, less than 20% of the 256 possible pyocin patterns have been assigned a type designation; and, unfortunately, there is no systematic way to assign types to newly discovered pyocinproduction patterns because the assignment of types to patterns has not followed any established rules. During the search for a better method to report bacteriocin and bacteriophage patterns, a mnemonic evolved which has greatly simplified the reporting of our typing results. Each of the tests is assigned a number from 1 to N where N is the number of tests employed. For example, in typing by bacteriocin production, the reaction against indicator strain 1 is designated test 1, the reaction against indicator strain 2 is designated test 2, and so on, until all tests are defined. The results of the first three tests are then assigned a number, as determined from the following mnemonic.
Each of the subsequent data triplets is assigned its proper number in a similar fashion. Thus, a test strain which has a bacteriocin production pattern (+—— —+— —++ +—+ ——— —+—) would be, by definition, type 564 386. If the number of tests is not evenly divisible by three, a second (-I- - =A,+- = B, — + =C,-- = D) and third (+ = E, - = F) mnemonic can be used to represent those results remaining after division into triplets. Each of the 2N possible patterns is automatically assigned a type designation according to these simple rules. Although this representation probably will not replace those already established by usage, it is hoped that it will be utilised as new typing systems are devised. Environmental Services Branch, Division of Research Services, National Institutes of Health,
Bethesda, Maryland 20014.
J. J. FARMER, III.
DIAGNOSIS OF PNEUMOCYSTIS CARINII INFECTION SiR,-Dr. Meuwissen and his colleagues2 state that the finding of antibody to Pneumocystis carinii in contacts of a patient can be used as corroborative evidence for infection in the patient. They thereby imply, firstly, that subclinical infection is spread by person-to-person contact and, secondly, that the presence of antibody to Pn. carinii in a healthy person indicates recent infection. Neither of these two possibilities has been suggested elsewhere, owing to the 1. 2.
Gillies, R. R., Govan, J. R. W. J. Path. Bact. 1966, 91, 339. Meuwissen, H. J., Brzosko, W. J., Nowoslawski, A., Good, Lancet, 1970, i, 1124.
R. A.