Transvaginal sonography—detection of findings suggestive of fetal chromosomal anomalies in the first and early second trimesters

Over a 4-year period, 14 dyskaryotic fetuses were diagnosed by amniocentesis, performed after early detection of malformations using transvaginal sonography (TVS). These 14 dyskaryotic fetuses were detected out of 4878 sonographic screenings performed by TVS between 9 and 16 weeks' gestation. Twenty-eight per cent of the referrals were at high risk and 72 per cent were at low risk for fetal malformations. Two hundred and twenty-nine fetuses (4.7 per cent) of the screened population had 265 anomalies, 39 per cent of them being transient. In 7 of the 14 dyskaryotic fetuses (50 per cent), the sonographically detected anomalies were transient, being undetected by follow-up sonographic screenings at later gestational ages (⩾18 weeks). Postponing the first sonographic scan aimed at malformation detection to a later gestational age may lead to transient anomalies and their associated dyskaryosis being missed.     

First-trimester maternal serum schwangerschafts protein 1 (SP1) in pregnancies associated with chromosomal anomalies

The relationship between first-trimester maternal serum Schwangerschafts protein 1 (SP1) and the karyotype of the pregnancy was examined in 692 women who underwent chorionic villus biopsy at 6–12 weeks. There were 30 pregnancies with abnormal karyotypes, consisting of 14 Down's syndrome (DS), eight trisomy 18, and eight other anomalies, two of which were mosaics. The normal ranges and medians for gestation were defined from the 662 cases in which the karyotype was normal. The median SP1 (0·5 MOM) of the abnormal group was significantly lower than that of the normal group (10 MOM). This relationship was maintained for the DS pregnancies (0·4 MOM) and for anomalies other than trisomy 18 (0·43 MOM) but not trisomy 18 (1·1 MOM). It is possible that the use of SP1 as a screening test for chromosome anomalies in the first trimester could have a 43 per cent detection rate for a 5 per cent false-positive rate.     

In vitro assessment of genotoxic and oxidative effects of zinc borate

Zinc borate is used as flame retardant for plastics and cellulose fibers, paper, rubber, and textiles. Despite its wide industrial use, there is limited information concerning its toxicity. The aim of the present study was to investigate the concentration dependence (0–280 mg L^?1) of its genotoxic activity on cultured human lymphocytes by using sister chromatid exchange and chromosomal aberration assays. Total antioxidant capacity and the extent of oxidative stress were also determined. Zinc borate was found to be non-genotoxic at all tested concentrations. It exhibited antioxidant activity at concentrations lower than 40 mg L^?1, and total oxidative stress levels were not changed at any applied concentration of zinc borate.     

Effect of latex material on antioxidant enzymes,lipid peroxidation,DNA damage,and chromosomal aberration

Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.     

The outcome of pregnancy and prenatal chromosomal diagnosis of fetuses in couples including a translocation carrier

In order to evaluate the relation between chromosomal translocation and the outcome of pregnancy, 50 couples were examined. Subjects consisted of 35 couples that included a reciprocal translocation carrier; 13 included a Robertsonian translocation carrier and 2 included a carrier of a mosaic reciprocal translocation. The reasons for performing chromosomal examinations were mainly infertility and abnormality of neonates. The rates of miscarriages and neonatal abnormalities in prior pregnancies were significantly higher than the birth rate of morphologically normal newborns. The presence of a translocation is closely related to reproductive failure because of the chromosomal imbalance. However, prenatal chromosomal examination after the 15th gestational week in subsequent pregnancies revealed that almost half of the fetuses showed normal karyotypes and only 12.8 per cent of the fetuses showed a chromosomal imbalance. Many chromosomally imbalanced fetuses are spontaneously aborted before amniocentesis. The risk of chromosomal imbalance is relatively low in prenatal diagnosis, but partial trisomies of small rearrangements tend to be preserved.     

The European collaborative study on mosaicism in chorionic villus sampling: Data from 1986 to 1987

Data on a total of 11 855 diagnostic chorionic villus samples obtained in the years 1986 and 1987 were compiled from a questionnaire filled in by 36 European cytogenetic centres. Mosaicism was reported in 141 cases. The cytogenetic findings were followed by induced abortion in 24 cases. Spontaneous abortion was observed in nine mosaic pregnancies, a rate not significantly different from that observed for CVS in total. Mosaicism was found in 1.2 per cent of analyses by direct analysis/short-term culture, in contrast to the 0.6 per cent found after long-term culture. Evidence for fetal non-mosaicism was found in 99 of the 141 cases. The finding of mosaicism in first-trimester CVS should always elicit further analyses, preferably after amniocentesis, to substantiate the suspected fetal chromosome aberration.     

Seven cases of trisomy 3 mosaicism in chorionic villi

This paper describes seven cases of confined chorionic mosaicism with trisomy 3. The chromosomally abnormal cell line in chorionic villi was revealed in three cases at diagnostic CVS and in four cases at the evacuation of the uterine cavity after a missed abortion had been diagnosed by ultrasound. In two of these cases, the abortion occurred after apparently normal development of the fetus during the second trimester of pregnancy. An evaluation of the effect of confined chorionic mosaicism with trisomy 3 on the viability of the conceptus has been attempted.     

Intrauterine growth retardation associated with chromosomal aneuploidy confined to the placenta. Three observations: Triple trisomy 6,21,22; trisomy 16; and trisomy 18

Cytogenetic analysis in three pregnancies revealed chromosomal mosaicism confined to chorionic villi. They were ascertained in the third trimester by intrauterine growth retardation (IUGR) in otherwise normal fetuses. In case of triple trisomy 6,21,22 and trisomy 16, it was obvious that these findings were most likely restricted to the placenta. These trisomies act as early lethal factors when they occur in the embryo itself. With trisomy 18, however, the interpretation of the cytogenetic finding remains ambiguous. The question arises as to whether an abnormal karyotype may be the cause of placenta insufficiency or is just coincidentally associated.     

Prenatal diagnosis of fetal anomalies during the second trimester of pregnancy: Their characterization and delineation of defects in pregnancies at risk

During a follow-up study of 19 790 pregnancies at risk for a genetic disease, from 1968 to 1989, 1083 fetuses were found to have an anomaly during the second trimester, leading to 977 terminations of pregnancy. Neural tube defects (31.4 per cent), chromosomal disorders (27.1 per cent), and Mendelian or multifactorial diseases (10.6 per cent) were the main causes of fetal anomaly. More than half (52.9 per cent) of the fetal anomalies were detected by routine ultrasound examination. Forty-two per cent of cystic hygromas were secondary to a chromosomal defect. We stress the importance of a comprehensive fetal and newborn examination to ensure an accurate diagnosis so that subsequently accurate counselling can be provided.