1013
Nevertheless, this single case strongly suggests that nucleoside phosphorylase, like adenosine deaminase, is essential for normal function of the immune system. This work was supported by grant AM 09745 from the National Institutes of Health and a grant from the John
frequencies.
Hartford Foundation. REFERENCES 1. Giblett, E. R., Anderson, J. E., Cohen, F., Pollara, B., Meuwissen, H. J. Lancet, 1972, ii, 1067. 2. Pickering, R. J., Pollara, B., Meuwissen, H. J. Clin. Immun. Immunopath. 1974, 3, 301. 3. Hirschhorn, R. J. clin. Invest. 1975, 55, 661. 4. Edwards, Y. H., Hopkinson, D. A., Harris, H. Ann. hum. Genet. 1971, 34, 395. 5. Kalckar, H. M. J. biol. Chem. 1947, 167, 461. 6. Hopkinson, D. A., Cook, P. J. L., Harris, H. Ann. hum. Genet. 1969, 32, 361. 7. Wara, D. W., Goldstein, A. L., Doyle, N. E., Ammann, A. J. New Engl. J. Med. 1975, 292, 70. 8. Chen, S. H., Scott, C. R., Giblett, E. R. Am. J. hum. Genet. 1974, 26, 103. 9. Turner, B. M., Fisher, R. A., Harris, H. Eur. J. Biochem. 1971, 24, 228. 10. Edwards, Y. H., Edwards, P. A., Hopkinson, D. A. FEBS Letters, 1973, 32, 235. 11. Siciliano, M. J., Wright, D. A., Shaw, C. R. Prog. med. Genet. 1974, 12, 17. 12. Green, H., Chan, T. S. Science, 1973, 182, 836. 13. Wolberg, G., Zimmerman, T. P., Hiemstra, K., Winston, M., Chu, L. C. ibid. 1975, 187, 957. 14. Huguley, C. M., Bain, J. A., Rivers, S., Scoggins, R. Blood, 1959, 14, 615.
15. Wada, Y., Nishimura, Y., Tanabu, M., Yoshimura, Y., Linuma, K., Yoshida, T., Arakawa, T. Tohoku J. exp. Med. 1974, 113, 25.
Normal amniotic fluid contains no fibrinogen,but it does have fibrinolytic potential which can be activated by streptokinase.8 F.D.P. have been described in amniotic fluid from pregnancies complicated by severe fetal distress and by intrauterine fetal death, but not in normal pregnancy.9 Our studies on amniotic-fluid F.D.P. originated as a comparison between normal and pre-eclamptic amniotic fluid, in which no significant difference in F.D.P. levels was detected.10 In this study, we have measured amnioticfluid F.D.P. levels in pregnancies complicated by fetal anencephaly and open spina bifida and have compared them with levels in normal pregnancy. MATERIALS
AND
METHODS
Samples were collected by transabdominal amniocentesis in preterm pregnancies, and by needle aspiration under direct amnioscopic vision in pregnancies at term. Samples were collected into 02M epsilon-aminocaproic acid to inhibit in-vitro fibrinolysis. Since it was essential to avoid contamination with fibrinogen, all samples were tested for blood by an o-tolidine method sensitive to 1 part whole blood in 218 parts amniotic fluid. All blood-contaminated samples were discarded. Blood-free samples were filtered through Whatman no. 1 filter paper, centrifuged for 10 minutes at 1500 g, refiltered, and stored at -20°C. Amniotic-fluid F.D.P. levels were measured by a tannedred-cell immunoassay,1l haemagglutination-inhibition modified to include prolonged sample incubation of up to 36 hours with sheep red cells, in order to remove all
Preliminary Communication RAISED AMNIOTIC-FLUID F.D.P. IN FETAL NEURAL-TUBE ANOMALIES D. W. PURDIE P. W. HOWIE W. EDGAR C. D. FORBES C. R. M. PRENTICE
University Departments of Medicine and Obstetrics, Royal Infirmary, Glasgow G4 0SF, and Glasgow Royal Maternity Hospital, Glasgow G4 0NA
Fibrin/fibrinogen degradation products (F.D.P.) have been measured in amniotic fluid from normal pregnancies and in pregnancies complicated by fetal anencephaly and open spina bifida. Statistically significant increases of amniotic-fluid F.D.P. levels were found in anencephalic pregnancies in the second trimester and third trimester, and also in spina-bifida pregnancies in the second trimester, when compared with levels in normal pregnancies. Amniotic-fluid F.D.P. may be of value as a protein marker in certain fetal neuralSum ary
Fig.
1—Amniotic-fluid
F.D.P.
levels
in
second-trimester
pregnancies.
tube anomalies. INTRODUCTION
EARLY diagnosis of fetal neural-tube anomalies by means of amniotic-fluid protein markers was first described by Brock and Sutcliffe,l who measured alpha-fetoprotein. Since then their work has been amply confirmed,2-4 and another potential marker, beta-trace protein, has been described experimentally in the Lewis rat 5 and in human anencephalic preg-
nancy.6s
FiB.
2—Amniotic-fluid
F.D.P.
levels
pregnancies. Results
expressed
as
mean ±1 S.D.
in
third-trimester
1014
heterophile antibody from the amniotic fluid. This test gave a sensitivity of up to 0’625 µg. F.D.P. per ml. amniotic fluid. RESULTS
Fig. 1 shows amniotic-fluid F.D.P. levels from second-trimester pregnancies (16-28 weeks). Compared with levels in normal pregnancies (mean 3-3 Mg. per ml.) there were significant increases both in cases with anencephaly (mean 133 µg. per ml., P
Nevertheless, this single case strongly suggests that nucleoside phosphorylase, like adenosine deaminase, is essential for normal function of the immune system. This work was supported by grant AM 09745 from the National Institutes of Health and a grant from the John
frequencies.
Hartford Foundation. REFERENCES 1. Giblett, E. R., Anderson, J. E., Cohen, F., Pollara, B., Meuwissen, H. J. Lancet, 1972, ii, 1067. 2. Pickering, R. J., Pollara, B., Meuwissen, H. J. Clin. Immun. Immunopath. 1974, 3, 301. 3. Hirschhorn, R. J. clin. Invest. 1975, 55, 661. 4. Edwards, Y. H., Hopkinson, D. A., Harris, H. Ann. hum. Genet. 1971, 34, 395. 5. Kalckar, H. M. J. biol. Chem. 1947, 167, 461. 6. Hopkinson, D. A., Cook, P. J. L., Harris, H. Ann. hum. Genet. 1969, 32, 361. 7. Wara, D. W., Goldstein, A. L., Doyle, N. E., Ammann, A. J. New Engl. J. Med. 1975, 292, 70. 8. Chen, S. H., Scott, C. R., Giblett, E. R. Am. J. hum. Genet. 1974, 26, 103. 9. Turner, B. M., Fisher, R. A., Harris, H. Eur. J. Biochem. 1971, 24, 228. 10. Edwards, Y. H., Edwards, P. A., Hopkinson, D. A. FEBS Letters, 1973, 32, 235. 11. Siciliano, M. J., Wright, D. A., Shaw, C. R. Prog. med. Genet. 1974, 12, 17. 12. Green, H., Chan, T. S. Science, 1973, 182, 836. 13. Wolberg, G., Zimmerman, T. P., Hiemstra, K., Winston, M., Chu, L. C. ibid. 1975, 187, 957. 14. Huguley, C. M., Bain, J. A., Rivers, S., Scoggins, R. Blood, 1959, 14, 615.
15. Wada, Y., Nishimura, Y., Tanabu, M., Yoshimura, Y., Linuma, K., Yoshida, T., Arakawa, T. Tohoku J. exp. Med. 1974, 113, 25.
Normal amniotic fluid contains no fibrinogen,but it does have fibrinolytic potential which can be activated by streptokinase.8 F.D.P. have been described in amniotic fluid from pregnancies complicated by severe fetal distress and by intrauterine fetal death, but not in normal pregnancy.9 Our studies on amniotic-fluid F.D.P. originated as a comparison between normal and pre-eclamptic amniotic fluid, in which no significant difference in F.D.P. levels was detected.10 In this study, we have measured amnioticfluid F.D.P. levels in pregnancies complicated by fetal anencephaly and open spina bifida and have compared them with levels in normal pregnancy. MATERIALS
AND
METHODS
Samples were collected by transabdominal amniocentesis in preterm pregnancies, and by needle aspiration under direct amnioscopic vision in pregnancies at term. Samples were collected into 02M epsilon-aminocaproic acid to inhibit in-vitro fibrinolysis. Since it was essential to avoid contamination with fibrinogen, all samples were tested for blood by an o-tolidine method sensitive to 1 part whole blood in 218 parts amniotic fluid. All blood-contaminated samples were discarded. Blood-free samples were filtered through Whatman no. 1 filter paper, centrifuged for 10 minutes at 1500 g, refiltered, and stored at -20°C. Amniotic-fluid F.D.P. levels were measured by a tannedred-cell immunoassay,1l haemagglutination-inhibition modified to include prolonged sample incubation of up to 36 hours with sheep red cells, in order to remove all
Preliminary Communication RAISED AMNIOTIC-FLUID F.D.P. IN FETAL NEURAL-TUBE ANOMALIES D. W. PURDIE P. W. HOWIE W. EDGAR C. D. FORBES C. R. M. PRENTICE
University Departments of Medicine and Obstetrics, Royal Infirmary, Glasgow G4 0SF, and Glasgow Royal Maternity Hospital, Glasgow G4 0NA
Fibrin/fibrinogen degradation products (F.D.P.) have been measured in amniotic fluid from normal pregnancies and in pregnancies complicated by fetal anencephaly and open spina bifida. Statistically significant increases of amniotic-fluid F.D.P. levels were found in anencephalic pregnancies in the second trimester and third trimester, and also in spina-bifida pregnancies in the second trimester, when compared with levels in normal pregnancies. Amniotic-fluid F.D.P. may be of value as a protein marker in certain fetal neuralSum ary
Fig.
1—Amniotic-fluid
F.D.P.
levels
in
second-trimester
pregnancies.
tube anomalies. INTRODUCTION
EARLY diagnosis of fetal neural-tube anomalies by means of amniotic-fluid protein markers was first described by Brock and Sutcliffe,l who measured alpha-fetoprotein. Since then their work has been amply confirmed,2-4 and another potential marker, beta-trace protein, has been described experimentally in the Lewis rat 5 and in human anencephalic preg-
nancy.6s
FiB.
2—Amniotic-fluid
F.D.P.
levels
pregnancies. Results
expressed
as
mean ±1 S.D.
in
third-trimester
1014
heterophile antibody from the amniotic fluid. This test gave a sensitivity of up to 0’625 µg. F.D.P. per ml. amniotic fluid. RESULTS
Fig. 1 shows amniotic-fluid F.D.P. levels from second-trimester pregnancies (16-28 weeks). Compared with levels in normal pregnancies (mean 3-3 Mg. per ml.) there were significant increases both in cases with anencephaly (mean 133 µg. per ml., P
