Pyruvate-kinase (PK) and creatine-kinase (CK) in normal pregnancy and its implication in genetic counseling of Duchenne muscular dystrophy (DMD).

The activities of pyruvate-kinase (PK) and creatine-kinase (CK) were measured in 50 normal pregnant women in both serum and amniotic fluid. Serum PK activity was found to be significantly higher in pregnant than in nonpregnant women, while serum CK did not differ significantly between the two population samples. In amniotic fluid, very little or no PK or CK activity was found. However, the mean PK activity in amniotic fluid obtained from women carrying male fetuses was significantly higher than in those carrying female fetuses. At the present time, it is concluded that if a woman at risk for having a son with Duchenne dystrophy is seeking genetic counseling when already pregnant her serum PK or CK should be compared with that of normal female pregnant controls. It is also suggested that determination of pyruvate-kinase in fetal blood might be used in addition to CK for prenatal diagnosis of Duchenne muscular dystrophy.

Prenatal diagnosis of neural tube defects: predictive value of AF-AFP in a low-risk population.

Amniotic fluid alpha-fetoprotein (AF-AFP) determinations were performed on 1,215 women who were at low risk for fetal neural tube defects and who were undergoing mid-trimester amniocentesis for cytogenetic indications, primarily age-related aneuploidy. Maternal sera obtained before amniocentesis and amniotic fluids were assayed in duplicate for alpha-fetoprotein by radioimmunoassay. Of the 1,215 low-risk women, eight (0.7%) had significant elevations of AF-AFP (greater than or equal to +5 SD). In none of the cases was the elevation associated with a fetal neural tube defect. Two cases with elevated AF-AFP were associated with chromosome aberrations; one with impending fetal demise; one with fetal blood contamination; and one case was due to a laboratory error. In one case, no source for the elevated AFP was found, and a normal infant was delivered at term. In the final two cases, the cause of the elevated AF-AFP was a fetal abdominal wall defect (one gastroschisis and one omphalocele). The predictive value of an elevated AFP varies with the population screened, and is reduced by routine ultrasonography before amniocentesis, which at least identifies anencephaly. In a low-risk population, an elevated AF-AFP is most often not associated with a fetal neural tube defect. Because of the low predictive value and the nonspecificity of AF-AFP, genetic counselors should reconsider the recommendation of routine AF-AFP in low-risk maternal populations.

Rh isoimmunization related to amniocentesis.

We report on the incidence of Rh isoimmunization after genetic amniocentesis at our institution. In 115 Rh negative women who underwent amniocentesis and subsequently delivered Rh positive infants, there were 4 (3.4%) sensitizations before birth. This was significantly greater than the 1.5% rate of gestational sensitization found in pooled populations of women who did not undergo amniocentesis. We also noted a significant increase in the number of sensitizations that occurred before 28 weeks. The results were consistent with those of previous studies of this issue, and are discussed in relation to current policies for managing Rh negative women who have second trimester amniocentesis.

Low material serum alpha-fetoprotein levels and congenital diaphragmatic defects.

We report on 2 cases of fetal congenital diaphragmatic defects with normal chromosomes among 105 patients referred for evaluation for low maternal serum alpha-fetoprotein (MSAFP) levels. The mechanism for this striking association is not clear. The association of low MSAFP levels and congenital diaphragmatic defects may have importance for MSAFP screening programs.

Fetal puncture during midtrimester amniocentesis.

Four cases of fetal puncture during midtrimester amniocentesis are reported; in one instance the baby apparently sustained temporary neurologic damage. None of the lesions was detected at the initial neonatal examination. From our data and a review of the literature, we estimate that fetal puncture occurs in 1-3% of midtrimester amniotic taps. The implications of the accident are not clear. We conclude that midtrimester amniocentesis should not be considered a routine benigh procedure; and whenever the use of this diagnostic modality is being considered, the prospective parents should be informed of its hazards.

Meconium staining of amniotic fluid at midtrimester amniocentesis.

Meconium-stained fluid was found in six of the first 234 amniocenteses performed at the University of Washington Prenatal Diagnosis Center. The taps were done between 16 and 20 weeks from the last menstrual period. Although in each case there was a factor that could have produced fetal distress, in no instance did intrauterine demise occur. All the pregnancies have terminated in the births of healthy children. Therefore, we believe that meconium staining of midtrimester amniotic fluid may in fact reflect a transient episode of fetal compromise but that the finding cannot be used to prognosticate either impending fetal death or the presence of congenital malformations in the newborn.

Azathioprine teratogenicity: review of the literature and case report.

An infant born with preaxial polydactyly to a mother taking azathioprine throughout pregnancy is described. Experimental studies in animals reveal a teratogenic role for azathioprine and its main metabolite, 6-mercaptopurine. The skeletal system appears to be the primary tissue target for such action of these drugs. Although no direct cause-effect relationship can be established from the single case presented, the similarity of this anomaly to experimental azathioprine teratogenesis suggests the necessity for further surveillance.

Ultrasonic placental localization and bloody taps in midtrimester amniocentesis for prenatal genetic diagnosis.

In a prospective study, a small team of obstetricians concurrently performed midtrimester amniocentesis for prenatal genetic diagnosis on 32 patients after ultrasonic placental localization and on 50 patients without prior ultrasound. The use of ultrasound did not affect the red cell count in the fluid samples. Furthermore, the 2 patient groups had similar rates of grossly bloody taps. The average number of viable clones after culture was lower both after bloody taps and when ultrasound had been used, but in neither case was the difference significant. There were no postamniocentesis complications in the entire patient population. These results suggest that ultrasonic placental localization is not helpful in avoiding bloody taps, and that bloody taps may not necessarily be dangerous. Therefore, since the long-range hazards of in utero exposure to ultrasound may not yet be known, it would seem judicious to use preamniocentesis ultrasound selectively and on specific indication, rather than routinely.

The premature breech: trial of labor or cesarean section?

Sixty-six premature breech deliveries were studied retrospectively. Forty-eight patients were permitted a trial of labor, 47 of whom ultimately delivered vaginally. Eighteen patients underwent cesarean section as soon as possible after their arrival at the delivery suite. When Apgar scores, perinatal mortality rates, cord prolapse, and entrapment of the aftercoming head are considered, cesarean section is probably the safer course of management for the patient with a footling breech infant, especially when the infant weighs 1500 g or less. However, the data indicate that a trial of labor can be safely undertaken in the presence of a premature frank or complete breech presentation.

Sperm penetration assay: useful test in evaluation of male fertility.

The recently developed sperm penetration assay (SPA) tests the functional capacity of sperm. It is based upon the ability of in vitro capacitated human spermatozoa to penetrate zona-free hamster eggs in vitro. The SPA was superior to seminal fluid analysis in predicting both fertility and infertility; in the prediction of infertility, the difference was highly significant. Data further indicated that fertility in the male may not remain constant with the passage of time. The SPA would appear to have wide application both clinically and experimentally.

Selection of human spermatozoa according to their relative motility and their interaction with zona-free hamster eggs.

Human spermatozoa were separated according to their motility by centrifuging semen on discontinuous Percoll gradients. Fractions of the gradients were examined for sperm motility, velocity, viability, morphology, bacteria, and sperm function using the hamster ova sperm penetration assay. The percentage of motile sperm increased from 40% to 60% motile sperm in 60% Percoll to 90% to 100% Percoll. Sperm velocity increased proportionately. Staining showed that greater than 90% of sperm in the 100% Percoll were alive and had normal morphology, and that only sperm cells were found in Percoll concentrations greater than 80%. Sperm isolated in the 80% to 100% Percoll fractions penetrated hamster ova much more frequently than sperm found in the 60% to 70% fractions or than sperm that had not been separated on a Percoll gradient.

Genital tract examinations and zona-free hamster egg penetration tests from men exposed in utero to diethylstilbestrol.

Because most men with prenatal exposure to diethylstilbestrol (DES) are still young and have not attempted to father children, its reproductive effects are uncertain. In a previous pilot study, we had noted an association between in utero DES exposure and reduced penetration of zona-free hamster eggs by sperm. To test these findings in a controlled manner, we performed physical examinations on 51 men with in utero DES exposure and 29 unexposed men and evaluated the penetration of zona-free hamster eggs by their sperm. Epididymal cysts or abnormalities of the prostate, testicle, or penile meatus were present in 37% of men with in utero DES exposure, versus 4% of nonexposed men (P less than 0.001). The mean proportions of penetrated eggs were 25% after in utero DES exposure and 29% in the nonexposed group (P greater than 0.57). The genital abnormalities related to DES exposure were not related to reduced egg penetration. We conclude that in utero exposure to DES is not related to a significant change in the penetration of zona-free hamster eggs by sperm.

The relationship of pyospermia and seminal fluid bacteriology to sperm function as reflected in the sperm penetration assay.

The relationship of the parameters of seminal fluid analysis (SFA) and seminal fluid leukocyte concentration to the in vitro sperm penetration assay (SPA) was studied in 217 men from infertile couples. Significant positive correlations were found between the SPA and sperm count, sperm motility, and morphologically normal sperm. The total number of leukocytes per milliliter, the number of polymorphonuclear leukocytes per milliliter (PMN), and the number of lymphocytes per milliliter were negatively correlated with the results of the SPA. The strongest correlation with an abnormal SPA (less than 11% of eggs penetrated) was the presence of greater than or equal to 1 PMN/100 sperm (8.17 increased relative risk of an abnormal SPA). The most important predictor variables of the percent penetration of the sperm penetration assay were total numbers of leukocytes per milliliter, sperm count, and sperm motility. Microbiologic studies of semen were not correlated with SPA results or number of leukocytes in the semen.

Trisomy-18 and antepartal fetal distress.

Two cases are presented wherein cesarean section was performed because of evidence of intrauterine growth retardation and antepartal fetal distress. Both infants had the trisomy-18 syndrome. Attention is drawn to the fact that the combination of growth retardation and fetal distress sometimes heralds the presence of severe anomalies in the fetus, and it is suggested that cesarean section should not be performed before one attempts to rule out such life-threatening abnormalities.

Novel mechanisms of reproduction: preimplantational ectogenesis.

The polarization of attitudes concerning preimplantational ectogenesis, combined with the fact that the field is technically in its infancy, makes likely the passage of much time before the use of ectogenesis becomes widespread either clinically or as a research tool. It is to be hoped that during this interval a properly critical attitude will lead to slow, steady progress while society readjusts some basic philosophic concepts.

Therapy of genetic diseases: a three-level approach.

Therapy of genetic diseases may be attempted at three different levels in the evolution of the disease process. At the first level, after clinical manifestations have appeared, methods are symptomatic and include diet, drugs, surgery, and avoidance of hazardous substances. At the second level, midway between the origin of the disease and the appearance of clinical manifestations, therapy consists of administration of a normal gene product, such as insulin in diabetes and factor VIII in hemophilia. At the third level, the origin of the disease, methods involve correcting the gene defect and are currently under investigation.