Concentrations of mercury, cadmium and lead in brain and kidney of second trimester fetuses and infants

The concentrations of mercury (Hg), cadmium (Cd) and lead (Pb) in brain (cerebrum) and kidney during fetal (second trimester terminations or abortions, n = 20) and postnatal (infants deceased before three months of age, n = 15) development have been studied. Information on possible sources of exposure was obtained from the mothers of the fetuses, but not from those of the infants. The median concentration of Hg in the brain was 4 micrograms/ kg wet weight in both fetuses and infants (total range < or = 2-23 micrograms/kg). The concentrations of Hg in the kidneys were significantly higher than in brain, median of Hg 6 micrograms/kg (range < or = 5-34 micrograms/kg) in fetuses and 10 micrograms/kg (< or = 7-37) in infants. There was a tendency of increasing concentration of Hg in the fetal kidney, but not in the brain, with increasing number of amalgam fillings in the mothers. The concentration of Cd in the brain was less than 1 microgram/kg in most cases, both in fetuses and infants. The concentration of Cd in the kidneys was significantly higher, with a median of about 2 micrograms/kg (1-8 micrograms/kg) in both groups. There was no detectable association between tissue Cd concentrations and the smoking habits of the mothers. The concentration of Pb in brain was below 10 micrograms/kg in most cases. In the kidneys, the concentrations of Pb were significantly higher, with a median of 12 micrograms/kg in the fetuses (range < or = 6-20 micrograms/kg) and 15 micrograms/kg (< or = 9-36 micrograms/kg) in the infants. In general, the concentrations of Cd and Pb were lower than in previously reported studies.

Lack of evidence of permanent engraftment after in utero fetal stem cell transplantation in congenital hemoglobinopathies

The use of fetal hematopoietic stem cells for in utero transplantation to create permanent hematochimerism represents a new concept in fetal therapy. In one fetus with alpha-thalassemia, one with sickle cell anemia, and one with beta-thalassemia, we have transplanted fetal liver cells obtained from legal abortions in gestational weeks 6-11. The fetus with alpha-thalassemia was transplanted twice during pregnancy, in the 15th (20.4 x 10(8) cells/kg) and in the 31st weeks of gestation (1.2 x 10(8) cells/kg), and is now two years of age. One fetus with sickle cell anemia received its transplant in the 13th week of gestation (16.7 x 10(8) cells/kg), and is now one year old. The fetus with beta-thalassemia was transplanted in 18th week (8.6 x 10(8) cells/kg), and is now three months old. Engraftment was evaluated by chromosomal analysis (sex chromosomes), red cell phenotyping, HLA class I and II typing, and PCR (polymerase chain reaction) for Y chromosome-specific sequences and DNA polymorphisms in cord and peripheral blood. The children with alpha- and beta-thalassemia underwent bone marrow aspirations at 3 and 7 months of age, respectively. In neither of these cases were we able to detect convincing evidence of stem cell engraftment. Thus, the administration of fetal stem cells to fetal recipients after the 12th week of gestation did not result in permanent hematochimerism. It remains to be determined whether the engraftment process can be promoted by earlier transplantations and/or higher cell doses.

Swedish survey on extra structurally abnormal chromosomes in 39 105 consecutive prenatal diagnoses: prevalence and characterization by fluorescence in situ hybridization

During 7 years (1985-1992), 39,105 consecutive prenatal diagnoses (34,908 amniocenteses and 4197 chorionic villus samples) were made at the five largest clinical genetic laboratories in Sweden. Thirty-one cases of extra structurally abnormal chromosomes (ESACs) were found, giving a total prevalence of 0.8 per 1000. Twelve ESACs were inherited, 14 were de novo and in five the parental origin was unknown. This gives an estimated prevalence of 0.3-0.4 per 1000 for familial and 0.4-0.5 per 1000 for de novo ESACs. Retrospectively, the ESACs were characterized by fluorescence in situ hybridization (FISH). In nine cases, no material was available for this analysis. In 21 of the remaining 22 cases, the chromosomal origin could be identified by FISH. Seventeen of these (81 per cent) were derived from the acrocentric chromosomes, of which 13 originated from chromosome 15 (62 per cent). The most common ESAC was the inv dup(15) (57 per cent). Two cases were derived from chromosome 22, one from chromosome 14, and one from either chromosome 13 or chromosome 21. The four remaining cases consisted to two i(18p)s and two small ring chromosomes derived from chromosomes 4 and 19, respectively.

Screening of fetal stem cells for infection and cytogenetic abnormalities

Fetal stem cell transplantation may rely on material from therapeutic abortions. It is essential that the stem cell transplant does not transmit any microorganisms that may affect the fetus and that genetically abnormal cells are avoided. To evaluate such contamination, human fetal stem cells collected February 1992 - December 1993 were analyzed for bacterial and fungal growth, and the placentas were karyotyped. Four samples of 70 were positive for different pathogens. Serological screening of 43 women during this period resulted in five seroconversions and revealed one carrier of anti-HCV. Karyotyping revealed two abnormal findings out of 72 samples. Thus, the concept of using material from therapeutic abortions is safe.

Direct and inverted reciprocal chromosome insertions between chromosomes 7 and 14 in a woman with recurrent miscarriages

We present the first case of direct and inverted reciprocal chromosome insertions between human chromosomes 7 and 14, ascertained because of repeated spontaneous abortions. Prometaphase GTG banding analysis showed the karyotype to be 46, XX, inv ins (7;14)(7pter-->7q11.23::14q32.2-->14q 22::7q21.2-->7qter), dir ins(14;7)(14pter-->14q 22::7q11.23-->7q21.2::14q32.2-->14qter). Origins of the insertion have been confirmed by chromosome painting with libraries specific for chromosomes 7 and 14 using fluorescence in situ hybridization.

Multifetal pregnancy reduction in Sweden. Utilization rate and pregnancy outcome (1986-1992)

All departments of Obstetrics and Gynecology, as well as all private clinics in Sweden offering assisted conception, were surveyed by means of a questionnaire to determine the utilization rate and outcome of multifetal pregnancy reduction (MFR) for the period 1 January 1986 to 30 June 1992. The response rae was 100%. Multifetal reduction was performed in 26 women, giving an average utilization rate of 1/7 multiple births of three or more for the entire period. Of the various techniques used, intracardiac or intrathoracic injection of a potassium chloride solution was predominant. The experience of each center with multifetal reductions varied between one and six procedures. In this series, the overall complete pregnancy loss was 27% (n = 7). In 73% (n = 19) of women the pregnancy continued to delivery. One fetus died in utero in the second trimester, one child died from a subtentorial hemorrhage perinatally, and one child had a malformation of the right foot and hand. It seems necessary to limit MFR to a few centers in Sweden in order to maintain and increase the experience of the operators involved, and to decrease the fetal loss rate associated with the procedure. However, the ultimate goal is to make these procedures unnecessary when methods of avoiding excessive ovulation are refined and by limiting the number of replaced embryos in IVF-treatment.

Establishment of a tissue bank for fetal stem cell transplantation

STUDY OBJECTIVE

To analyse the yield of fetal liver tissue in first trimester abortions and to evaluate the number of nucleated cells obtained from each fetal liver during the sixth to twelfth week of gestation.

DESIGN

Prospective descriptive study:

LOCATION

University Hospital.

MATERIAL

Women seeking abortion during a 12 month period 1992/1993.

RESULTS

Out of 1271 women seeking abortion, 152 were asked whether they were willing to donate fetal tissue for fetal transplantation. Of these women, 105 (69%) accepted the proposal and underwent a modified low suction vacuum curettage. Fetal liver tissue was obtained in 61 (58%) of these procedures. The frequency at which tissue was retrieved was strongly related to gestational age and rose from 29% in week 6 to 79% in the tenth to twelfth week of gestation. The mean number of nucleated cells obtained from each fetal liver demonstrated a concomitant increase with gestational age, rising from 16 to 43 x 10(6) per liver during these weeks of gestation. Of the 61 cases in which fetal liver was obtained, four subjects were shown to be abnormal by laboratory analyses and 11 did not alter the mandatory follow-up appointment. This left 46 cases for use in the program of fetal to fetal transplantations.

CONCLUSIONS

Most women seeking abortion seem to be in favor of the idea of fetal tissue donation for the treatment of other fetuses. The possibility of obtaining fetal liver tissue and the number of fetal stem cells retrieved are closely correlated to gestational age. A tissue bank appears to facilitate the operation of a fetal to fetal stem cell transplantation program.

Complex genetic counseling and exclusion of Duchenne muscular dystrophy in a twin pregnancy after in vitro fertilization (IVF)

A twin pregnancy following in vitro fertilization-embryo transfer coincidentally at risk for the X-linked recessive Duchenne muscular dystrophy is described. First-trimester prenatal diagnosis by transabdominal chorionic villus samplings on the dichorionic placentae and molecular linkage analysis could exclude the disorder in both fetuses. Genetic counseling and prenatal diagnosis were particularly complex due to the twin pregnancy, the need for linkage analysis, and confined placental mosaicism 45,X/46XX in one of the fetuses. All parties should be aware that additional invasive diagnostic procedures in the second trimester might be required. It is proposed that, in similar situations, only one, arguably two, fertilized egg be transferred at a time to facilitate prenatal diagnosis and decision making for these rare couples. This problem, however, may be increasingly overcome by preimplantation diagnosis.

Characterization of supernumerary ring marker chromosomes by fluorescence in situ hybridization (FISH)

Five cases with small supernumerary ring chromosomes are characterized at the molecular level. Routine chromosome banding analysis was insufficient for identification of the ring chromosomes, and none of them was DA/DAPI positive. Fluorescence in situ hybridization utilizing repetitive centromeric probes for all chromosomes has determined that one of these five ring chromosomes originates in each of chromosomes 4, 7, 8, 9, and 20. Chromosome painting with chromosome-specific libraries has confirmed this and excluded the involvement of additional chromosomes in the rearrangements.

Prenatal diagnosis of distal arthrogryposis type I by ultrasonography

Two consecutive pregnancies in a woman with initially undiagnosed type I distal arthrogryposis (DA) are reported. A prenatal diagnosis of the condition was made by ultrasound in the 17th week of gestation in one of the pregnancies, whereas in the subsequent pregnancy the disorder was excluded as early as 13 weeks' gestation. The diagnoses were verified at birth. The feasibility of prenatal diagnosis of DA type I in the second trimester is thus confirmed and its possibility in the late first trimester is suggested.

Prenatal investigation of a 45,X/46,X,r(?) karyotype in amniocytes using fluorescence in situ hybridization with an X-centromeric probe

The karyotype of cultured amniotic fluid cells obtained on the indication of advanced maternal age was shown to be a mosaic 45,X/46,X,r(?). The small size and banding pattern made it difficult to determine whether the ring was derived from and X or a Y chromosome, or even from an autosome. By using an X-centromeric probe and fluorescence in situ hybridization (FISH), we demonstrated the ring to have an X centromere. Thus, a more complete genetic counselling was possible. This confirms the usefulness of FISH in identifying and characterizing this and other chromosome rearrangements in prenatal diagnosis.

Color Doppler studies in trophoblastic tumors: a preliminary report

Ten women, referred because of a strong suspicion of gestational trophoblastic neoplasia, were examined by abdominal real-time ultrasound and color Doppler. The results were compared to those of pelvic angiography. In all but one case color Doppler examination revealed areas of increased vascularity. In all cases the findings of color Doppler and pelvic angiography agreed. Real-time ultrasound failed to detect abnormal uterine echoes in three of the patients where the other methods indicated tumor. The present study indicates that color Doppler could be of great value in a non-invasive assessment of trophoblastic tumors.

European collaborative study on prenatal diagnosis: mosaicism, pseudomosaicism and single abnormal cells in amniotic fluid cell cultures

A report is given of the results of a European collaborative study on mosaicism, pseudomosaicism and single abnormal cells in amniotic fluid cell cultures. The mean frequency of cases with mosaicism was 0.10 per cent, with pseudomosaicism 0.64 per cent and with single abnormal cells 2.83 per cent in a series of 44 170 amniotic fluid samples. There was no significant difference between the colony (in situ) and the flask method with regard to the frequency of mosaicism. Pseudomosaicism and single abnormal cells were more frequent in cases studied with the flask method probably due to other factors than the method of cultivation of the cells. The frequency of maternal cell contamination was 0.17 per cent and the frequency of wrong sex assignment was 0.11 per cent. A more correct estimation is obtained if these frequencies are doubled. There was a considerable variation between laboratories with regard to the frequencies given above. One reason for this variation is that there are no sharp limits between mosaicism, pseudomosaicism and single abnormal cells. Thus the material contained cases diagnosed as having pseudomosaicism which turned out to be mosaics at birth and to have an abnormal phenotype. These cases were very rare but pose a definite problem in prenatal cytogenetic diagnosis.

Prenatal diagnosis of chondroectodermal dysplasia with fetoscopy

Chondroectodermal dysplasia (Ellis-van Creveld syndrome) has previously been diagnosed prenatally only once, using fetoscopy. We report on two consecutive pregnancies in a woman at risk of having a child with the syndrome during which fetoscopic visualization was performed. Ellis-van Creveld syndrome was diagnosed prenatally in one instance, while it could be excluded in the other one. Non-invasive prenatal diagnosis of the syndrome is discussed.

The 11q;22q translocation: a collaborative study of 20 new cases and analysis of 110 families

Following a previous collaborative study (Fraccaro et al. 1980), 20 new cases of 11q;22q translocation are described. Twelve families were ascertained through an unbalanced carrier of the translocation and eight cases were ascertained as balanced carriers. A segregation analysis was performed on the 110 families so far published. It was concluded that the 11q;22q translocation is a relatively frequent event, and that all the cases thus far reported might have the same breakpoints at 11q23.3 and 22q11.2. The translocation seems to be independent of environmental factors and it seems to have a low rate of mutation as indicated by the scarcity of de novo cases. The new data confirmed that only one type of unbalanced karyotype (47,XX or XY+der(22)t(11;22)(q23.3;q11.2)) is found among the offspring of the translocation carriers. The minimal overall recurrence risk for an unbalanced translocation was estimated to 2%. There was no difference between the recurrence risks for male and female balanced carriers, while the trend was confirmed of an excess of female balanced carriers among the phenotypically normal offspring of the t(11;22) female carriers.

Dyggve-Melchior-Clausen dysplasia. Morphological and biochemical findings in cartilage growth zones

The results of light and electron microscopic examination and of biochemical proteoglycan studies of costochondral and iliac crest biopsies from a recently diagnosed case of Dyggve-Melchior-Clausen dysplasia are reported. At light microscopy of resting cartilage large lacunae containing clusters of five or more chondrocytes were seen in some areas. In the hyaline cartilage there were scattered fibrous foci but no mineralized areas. Electron microscopy revealed chondrocytes containing widened cisternae of rough endoplasmic reticulum and vesicles coated with a smooth single-layered membrane. The content of the cisternae and of the vesicles was amorphous. Throughout the cartilage a considerable proportion of the chondrocytes displayed more or less pronounced necrobiotic changes. The biochemical analysis showed an increased amount of glucosaminoglycans in the cartilage and indicated that the ability of proteoglycan monomers to reaggregate to hyaluronic acid chains was decreased. Our findings support the suggestion that Dyggve-Melchior-Clausen dysplasia is due to a disturbance in proteoglycan metabolism.

A familial pericentric inversion of chromosome 8 analysed with a high resolution chromosome banding technique

A familial pericentric inversion of chromosome 8 is described. The break points were localized by a high resolution chromosome banding technique and found to be inv(8)(p23.108q12.100). None of the family members had an unbalanced product of the inversion. There were no phenotypical abnormalities in the carriers. The break points and segregation pattern are compared with those of previously reported pericentric inversion of chromosome 8.