422 absence of symptoms in those that they had M.R. Furthermore, the absence of neurological defects (seizure disorders, hemiplegia, cerebral palsy, optic atrophy) also speaks against the host-resistance theory. The absence of any history of change in developmental progress or intelligence of the thirty- . one children with M.R. of unknown aetiology suggests that the same degree of M.R. was present at birth. It is difficult to accept that lead poisoning which has such protean manifestations and such varying sequels should present consistently as insidious
However, there was a consistent subjects so profoundly affected
M.R. only: David et al. refer to possible gaps in the prenatal and perinatal histories of the aetiology-unknown group. Since an accurate is the basis on which the two M.R. groups are disfrom each other, this is a serious omission. There is-no justification for assuming a history is negative if it is unknown. They state that if the aetiology were known, it would lead to a lowermean blood-lead in this group. The reverse is true. As children with higher blood-lead move from the unknown to the known category, the difference in mean must decrease or disappear. The control group, selected only for age and sex, also lacks prenatal and perinatal history. Of the 33 probable causes 9 were high-risk maternal factors, 16 were high-risk perinatal factors, and 2 were infections. Because of the frequency with which these factors are encountered, particularly in a predominantly Black clinic population, omission of such pertinentdata from both the control and the aetiology-unknown groups compromises the design structure of this study. The conclusion was that any rise in blood-lead above 24.5 µg/dl must be recognised as potentially noxious, but the mean blood-lead for the approximately one million children screened in New York and Chicago in the past 10 years was approximately 25 µg/dl.6 If the ceiling that David et al. propose is accepted, every second child will exhibit low-lead toxicity and will be regarded as potentially retarded.
history
tinguished
182 La Pier Street, Glencoe, Illinois 60022, U.S.A.
HENRIETTA K. SACHS
ser-
um) phenylalanine hydroxylase in controls and patients with classical phenyleketonuria (P.K.U.). Many metabolic and enzyme studies have been done in the search for ways of discriminating between the different variants of P.K.u. and hyperphenylalaninxmia. However, enzyme studies show that the genetic defect in P.K.U. can be located at several steps in the phenylalanine hydroxylation system, so the discriminatory power of phenylalanine hydroxylase alone in the establishment of P.x.u. is controversial. Using the method applied in their studies in cultured fibroblasts Hoffbauer et al. measured phenylalanine-hydroxylase activities in the plasma of controls and P.K.U. patients, and concluded that P.K.U. can be diagnosed by enzyme-activity measurements in plasma. Their results, however, do not seem conclusive. Patients A and C had enzyme activities of0 ± 3-7 and 0 ±2.7pmol/h/mg protein, respectively. A mean value of zero in combination with s.D. of 3-7 and 2-7 can only be achieved when some enzyme activities are negative, and such values would have to be attributed to the inaccuracy of the method. If the method carries such a large s.D., then the phenylalanine-hydroxylase activities in individual patients with P.K.u. do not differ significantly from the control group. This is true for patients A, C, E, and F (four out of the six patients A., Sachs, H. K., Murray, E. F., O’Connell, M. J. Pediatrics, 1969, 44, 661; and personal communications. 7. Hoffbauer, R. W., Schrempf, G. Mönch, E. Lancet, 1976, ii, 1031. 8. Hoffbauer, R. W., Schrempt, G. ibid. p. 194. 6. Blanksma, L.
University Children’s Hospital, Wilhelmina Kinderziekenhuis, Utrecht, Netherlands
C.
VAN DER
HEIDEN
TUBOCORNUAL ANASTOMOSIS FOR REVERSAL OF STERILISATION
SIR,—MR Winston (Feb. 5, p. 284) is to be congratulated on his results for microsurgical tubocornual anastomosis for reversal of sterilisation. A review of my 41 cases of reversal of sterilisation showed that 13 had been treated by tubouterine anastomosis only, with 8 pregnancies to date. 1 of these fol= lowed reversal of the only case of diathermy laparoscopic sterilisation referred. Of the 5 patients not pregnant 3 had postoperative salpingography and all of these showed patent tubes. There were no ectopic pregnancies. These anastomoses were performed using a reamer. Oxytocin injected down the track before reaming may help to account for the lack of copious bleeding mentioned by Mr Win:ton as a drawback to this procedure. The tube is shortened in both operations, but we do not know if this matters as long as the ovary is placed adjacent to the fimbrial end. Both series show a 60-70% pregnancy-rate. Until much larger series are available neither Mr Winston’s figures nor mine can tell us whether tubocornual anastomosis or tubouterine implantation is the better procedure. Both sets of figures, however, suggest that sterilisation is not so irreversible and certainly laparoscopic diathermy sterilisation is now reversible. of Obstetrics and Gynæcology, Bronglais General Hospital, Aberystwyth, Dyted SY23 1ER
Department
G. F. WILLIAMS
CAUSES OF LATE ABORTION
PHENYLALANINE HYDROXYLATION IN PHENYLKETONURIA
SIR,—Hoffbauer et al,presented data about plasma (or
Thus the mean values and s.D., calculated for the whole group of P.K.U. patients and for the controls do not permit any conclusion about the discriminatory quality of phenylalanine-hydroxylase activity measurements in plasma in the detection ofp.K.u.
investigated).
SIR,—As your Parliamentary correspondent (Jan. 29, p. 266) noted, it seems that Mr William Benyon’s private member’s Bill will propose, inter alia, an upper limit of 20 weeks’ gestation for legal abortions with exceptions up to 24 weeks for "hard cases". I have interviewed forty "late aborters" assessed
gestation-who
clinically as being between 20 and 24 weeks’ had prostaglandin abortions at two
non-N.H.S. clinics. All had felt fetal movements. As might be expected, many were young primigravidas. The average age was 18.5 years (range 15-37) but eighteen were aged 16 or under. Seven (17-5%) had had a previous pregnancy, only one of which had been aborted. Ten women first suspected pregnancy between the 4th and 7th week and fifteen between the 8th and llth week. Five did not suspect until the 20th week or later. Three women did not suspect at all and were found to be pregnant when they consulted their doctor for abdominal discomfort (two) or vaginal discharge (one). Eleven patients had a history of significant menstrual irregularity, defined as at least one month overdue. Consequently some of them had good reason to assume at first that they were not pregnant. One patient had an imperforate hymen and haematocolpos, and conceived after hymenotomy without ever having had a period. Three women had sporadic vaginal bleeding during the pregnancy and had assumed that they simply had irregular menstruation. Surprisingly there were no menopausal women in this sample although they do present from time to time. In fourteen cases what might be called "wishful thinking" was a major cause of delay in seeking abortion. Wishful thinkers either persuaded themselves that they were not preg-
However, there was a consistent subjects so profoundly affected
M.R. only: David et al. refer to possible gaps in the prenatal and perinatal histories of the aetiology-unknown group. Since an accurate is the basis on which the two M.R. groups are disfrom each other, this is a serious omission. There is-no justification for assuming a history is negative if it is unknown. They state that if the aetiology were known, it would lead to a lowermean blood-lead in this group. The reverse is true. As children with higher blood-lead move from the unknown to the known category, the difference in mean must decrease or disappear. The control group, selected only for age and sex, also lacks prenatal and perinatal history. Of the 33 probable causes 9 were high-risk maternal factors, 16 were high-risk perinatal factors, and 2 were infections. Because of the frequency with which these factors are encountered, particularly in a predominantly Black clinic population, omission of such pertinentdata from both the control and the aetiology-unknown groups compromises the design structure of this study. The conclusion was that any rise in blood-lead above 24.5 µg/dl must be recognised as potentially noxious, but the mean blood-lead for the approximately one million children screened in New York and Chicago in the past 10 years was approximately 25 µg/dl.6 If the ceiling that David et al. propose is accepted, every second child will exhibit low-lead toxicity and will be regarded as potentially retarded.
history
tinguished
182 La Pier Street, Glencoe, Illinois 60022, U.S.A.
HENRIETTA K. SACHS
ser-
um) phenylalanine hydroxylase in controls and patients with classical phenyleketonuria (P.K.U.). Many metabolic and enzyme studies have been done in the search for ways of discriminating between the different variants of P.K.u. and hyperphenylalaninxmia. However, enzyme studies show that the genetic defect in P.K.U. can be located at several steps in the phenylalanine hydroxylation system, so the discriminatory power of phenylalanine hydroxylase alone in the establishment of P.x.u. is controversial. Using the method applied in their studies in cultured fibroblasts Hoffbauer et al. measured phenylalanine-hydroxylase activities in the plasma of controls and P.K.U. patients, and concluded that P.K.U. can be diagnosed by enzyme-activity measurements in plasma. Their results, however, do not seem conclusive. Patients A and C had enzyme activities of0 ± 3-7 and 0 ±2.7pmol/h/mg protein, respectively. A mean value of zero in combination with s.D. of 3-7 and 2-7 can only be achieved when some enzyme activities are negative, and such values would have to be attributed to the inaccuracy of the method. If the method carries such a large s.D., then the phenylalanine-hydroxylase activities in individual patients with P.K.u. do not differ significantly from the control group. This is true for patients A, C, E, and F (four out of the six patients A., Sachs, H. K., Murray, E. F., O’Connell, M. J. Pediatrics, 1969, 44, 661; and personal communications. 7. Hoffbauer, R. W., Schrempf, G. Mönch, E. Lancet, 1976, ii, 1031. 8. Hoffbauer, R. W., Schrempt, G. ibid. p. 194. 6. Blanksma, L.
University Children’s Hospital, Wilhelmina Kinderziekenhuis, Utrecht, Netherlands
C.
VAN DER
HEIDEN
TUBOCORNUAL ANASTOMOSIS FOR REVERSAL OF STERILISATION
SIR,—MR Winston (Feb. 5, p. 284) is to be congratulated on his results for microsurgical tubocornual anastomosis for reversal of sterilisation. A review of my 41 cases of reversal of sterilisation showed that 13 had been treated by tubouterine anastomosis only, with 8 pregnancies to date. 1 of these fol= lowed reversal of the only case of diathermy laparoscopic sterilisation referred. Of the 5 patients not pregnant 3 had postoperative salpingography and all of these showed patent tubes. There were no ectopic pregnancies. These anastomoses were performed using a reamer. Oxytocin injected down the track before reaming may help to account for the lack of copious bleeding mentioned by Mr Win:ton as a drawback to this procedure. The tube is shortened in both operations, but we do not know if this matters as long as the ovary is placed adjacent to the fimbrial end. Both series show a 60-70% pregnancy-rate. Until much larger series are available neither Mr Winston’s figures nor mine can tell us whether tubocornual anastomosis or tubouterine implantation is the better procedure. Both sets of figures, however, suggest that sterilisation is not so irreversible and certainly laparoscopic diathermy sterilisation is now reversible. of Obstetrics and Gynæcology, Bronglais General Hospital, Aberystwyth, Dyted SY23 1ER
Department
G. F. WILLIAMS
CAUSES OF LATE ABORTION
PHENYLALANINE HYDROXYLATION IN PHENYLKETONURIA
SIR,—Hoffbauer et al,presented data about plasma (or
Thus the mean values and s.D., calculated for the whole group of P.K.U. patients and for the controls do not permit any conclusion about the discriminatory quality of phenylalanine-hydroxylase activity measurements in plasma in the detection ofp.K.u.
investigated).
SIR,—As your Parliamentary correspondent (Jan. 29, p. 266) noted, it seems that Mr William Benyon’s private member’s Bill will propose, inter alia, an upper limit of 20 weeks’ gestation for legal abortions with exceptions up to 24 weeks for "hard cases". I have interviewed forty "late aborters" assessed
gestation-who
clinically as being between 20 and 24 weeks’ had prostaglandin abortions at two
non-N.H.S. clinics. All had felt fetal movements. As might be expected, many were young primigravidas. The average age was 18.5 years (range 15-37) but eighteen were aged 16 or under. Seven (17-5%) had had a previous pregnancy, only one of which had been aborted. Ten women first suspected pregnancy between the 4th and 7th week and fifteen between the 8th and llth week. Five did not suspect until the 20th week or later. Three women did not suspect at all and were found to be pregnant when they consulted their doctor for abdominal discomfort (two) or vaginal discharge (one). Eleven patients had a history of significant menstrual irregularity, defined as at least one month overdue. Consequently some of them had good reason to assume at first that they were not pregnant. One patient had an imperforate hymen and haematocolpos, and conceived after hymenotomy without ever having had a period. Three women had sporadic vaginal bleeding during the pregnancy and had assumed that they simply had irregular menstruation. Surprisingly there were no menopausal women in this sample although they do present from time to time. In fourteen cases what might be called "wishful thinking" was a major cause of delay in seeking abortion. Wishful thinkers either persuaded themselves that they were not preg-
