Tumour-associated antigens in maternal and fetal blood

Normal levels of cancer-associated antigen (CA) 19-9, neurone-specific enolase (NSE), cancer-associated antigen (CA) 125, and mucin-like carcinoma-associated antigen (MCA) during pregnancy were determined in 87 mothers and fetuses, using a solid-phase sandwich enzyme immunoassay. CA 19-9 concentrations were higher in the fetuses, whereas the other three tumour-associated antigen levels were higher in the mothers. Only fetal NSE and MCA levels were positively correlated with those in maternal serum. Contrary to adult samples, no difference was demonstrated between male and female fetal levels of CA 125. MCA was the only maternal marker that increased significantly with gestational age between 20 and 34 weeks' pregnancy.     

Prenatal diagnosis of Lesch-Nyhan syndrome: Experience with three fetuses at risk

Our experience with the prenatal detection of the Lesch-Nyhan syndrome (LNS; hypoxanthine-guanine phosphoribosyltransferase (HGPRT) deficiency) in three fetuses at risk is reported. Enzyme activities were measured in cultured amniocytes in two pregnancies, and in tissues and cultures obtained from chorionic villus sampling (CVS) in a third pregnancy. In all tissues the specific activities of HGPRT and adenine phosphoribosyltransferase (APRT) were determined and APRT/HGPRT ratios were calculated. In addition to the enzyme assays, the rate of purine synthesis de novo was assessed in the two amniocyte cultures, and the rate of [¹⁴C]hypoxanthine incorporation into nucleotides and sensitivity to azaguanine were measured in one of the amniocyte cultures. We report the diagnosis of normal fetuses by study of amniocytes in two pregnancies and of LNS using CVS in one pregnancy. In all three cases the diagnosis was confirmed.     

First trimester prenatal diagnosis of Sandhoff's disease

Chorionic villus sampling was performed on two patients with a previous family history of Sandhoff's disease. Total β-hexosaminidase (Hex) activity in case 1 was within the normal range (case 1: 6365 μmol/h/g protein; control range: 3227-24 495/miol/h/g protein). The β-hexosaminidase isoenzyme pattern was found to be normal. These results were confirmed on cultured amniotic fluid cells. In case 2, the total Hex activity was 672 μmol/h/g protein, i.e., 7 per cent of the control mean (10 085 μmol/h/g protein), and chromatography demonstrated that more than 50 per cent of this activity was due to the abnormal isoenzyme β-hexosaminidase S (Hex S). The fetus was predicted to be affected by Sandhoff's disease and this was confirmed on fetal tissues after termination of pregnancy. This study demonstrates that a fetus affected by Sandhof's disease can be reliably diagnosed during the first trimester of pregnancy.     

Prenatal detection of limb defects after chorionic villus sampling

Prenatal sonographic diagnoses of two cases of severe limb defects after first-trimester chorionic villus sampling (CVS) are presented. Pathological examination after elective termination correlated well with the prenatal sonographic findings. Although the relationship between CVS and limb defects remains controversial, careful ultrasound examination for possible limb defects in cases receiving CVS is recommended.     

In situ hybridization studies for the detection of common aneuploidies in CVS

We have attempted to evaluate the efficiency of interphase cytogenetics in the detection of specific aneuploidies in chorionic villus samples. For this purpose, we used alphoid repetitive sequences specific for the chromosomes involved in the common aneuploidies, namely probes for chromosomes 13, 18, 21, X, and Y. These probes were applied to normal and abnormal CVS cases, as well as to a few mosaic cases. Results from these preliminary studies indicate that the technique can be very efficient for the detection of specific aneuploidies and can be particularly useful in the analysis of mosaic cases, which usually requires the screening of high number of metaphases.     

First-trimester diagnosis of hypophosphatasia. Importance of gestational age and of purity of CV samples

Prenatal diagnosis of hypophosphatasia was made by alkaline phosphatase (ALP) assay on a chorionic villous sample taken in the first trimester. Very low activities of the LBK isoenzyrnes indicated an affected fetus. Diagnosis was confirmed at 12 weeks of gestation by measurement of LBK isoenzyme activities in fetal bone tissue. In control chorionic villous samples an inverse relation was observed between LBK and placental ALP percentage during gestational age. High LBK ALP activities are observed in decidual tissue. Chorionic villous tissue must not be sampled after 12 weeks of gestation and decidual tissue must be excluded from the sample.     

Risk evaluation in chorionic villus sampling

The occasion of the 18th symposium of the European Society of Human Genetics, 20 May to 2 June, provided an opportunity for the WHO to sponsor a small meeting on the progress of risk evaluation in three large programmes of chorionic villus sampling (CVS). Their pooled information showed a rate of fetal loss of 3·4 per cent in the first 300 cases in each programme, falling to 1·7 per cent in the following 400 cases.     

扬尘估算的采样方法对比

AP-42方法是目前较为权威的一种扬尘总量估算方法,泥沙承载量作为该方法中重要参数之一,采样方法对其结果有非常大的影响.在详细介绍了'AP-42提供的采样方法'与'TRAKER方法'两种采样方法的具体实施步骤基础上,对两种方法进行对比,发现'AP-42提供的采样方法'操作规范,但工作量大,易受外部影响;而'TRAKER方法'更为先进,对于科学研究具有较大的利用价值,但采样结果转换公式是经验公式,存在一定误差.     

Resorbed co-twin as an explanation for discrepant chorionic villus results: Non-mosaic 47,XX, +16 in villi (direct and culture) with normal (46,XX) amniotic fluid and neonatal blood

Non-mosaic trisomy 16 was observed in chorionic villus cytotrophoblasts (direct) as well as cultured mesenchymal core cells derived from the pregnancy of a 38-year-old woman. Chromosome preparations from amniotic fluid and neonatal cultures (cord blood) were 46,XX. Normal fetal growth as determined by serial ultrasound examinations occurred throughout the pregnancy, which resulted in a healthy 2724 g female. Multiple biopsies taken from the umbilical cord, placental cotyledons, and fetal membranes were 46,XX. However, a placental nodule and three of six cultures initiated from membranes (amnion and chorion) showed 46,XX/47,XX, + 16 mosaicism. We propose that the trisomy 16 cells arose from residual villi derived from a trisomic cotwin that never developed. This case further demonstrates that normal fetal growth may presage normal outcome irrespective of cytogenetic findings in cytotrophoblasts (direct) and cultured mesenchymal core cells.     

Changes in maternal serum alpha-fetoprotein levels associated with intrauterine genetic diagnostic procedures

The amount of fetal—maternal transfusion during invasive intrauterine diagnostic instrumentation was determined by measuring the increase in maternal serum alpha-fetoprotein (Δ AFP) caused by the procedure. Fetal liver biopsy or fetoscopy for purposes other than blood sampling caused a mean Δ AFP of 11.4 ng/ml and 34.2 ng/ml, respectively. Fetoscopy with fetal blood sampling produced a mean Δ AFP of 211.8 ng/ml, while fetoscopy followed by placentesis caused a mean Δ AFP of 462.8 ng/ml (representing a 1.07 ml fetal—maternal transfusion). Although this magnitude of fetal—maternal transfusion is an acceptable risk for the fetus, it is a sufficient transfusion to cause blood cell antigen sensitization.