The preserving of chorionic villi before establishing long-term cell cultures for cytogenetic analysis

The possibility of preserving intact chorionic villi in culture medium for up to 7 days before establishing long-term cultures for prenatal chromosome analysis is demonstrated. The preserving itself had no negative effect on the growth capacity of the mesenchymal cells.     

提高大型锻件冲击韧性的技巧

为提高大锻模件的冲击韧性,从不同的角度对其关键的影响因素进行了深入分析与探讨。同时,提出了改进措施。     

烟尘平行采样计算程序的编制及应用

结合ＳＹＣ－Ⅲ型皮托管采样测试仪的特点,编制了具有一定通用性的烟尘平行采样计算程序。该程序包括从烟道布点至除法器评价等５个功能相对独立的计算模块。程序采用菜单选择数据变数输入方式,操作较简便,等速采样流量计算时间〈２０ｓ,具有跟踪烟气基本参数变化,计算均值,快速选取最佳采样嘴等性能。经实际应用于焦炉自动装煤除尘系统及推焦除尘系统的烟尘测定,结果与静压平衡法吻合。     

A pitfall in the prenatal diagnosis of Lesch-Nyhan syndrome by chorionic villus sampling

The ratio of the activities of catabolic enzymes such as 5′-nucleotidase and purine nucleoside phosphorylase to that of hypoxanthine-guanine phosphoribosyltransferase (HPRT) may be much higher in frozen or cultured chorionic villus cells than in cultured amniotic fluid cells, cultured fibroblasts, or red blood cells. Consequently, unless these catabolic activities are controlled the observed activity of HPRT may be greatly decreased, and a false diagnosis of Lesch-Nyhan syndrome may result. For a reliable diagnosis, the reaction products of HPRT must be protected from catabolism.     

Proliferation kinetics in native chorionic villus cells

In accordance with observations by other groups direct CVS preparations reveal only a few mitoses, whereas semi-direct cultures (overnight incubation) give good results. By monitoring the BrdU uptake with an immunological method, a delay in the proliferation activity in native villi could be observed up to 7 h after biopsy.     

The fetal intrahepatic umbilical vein as an alternative to cord needling for prenatal diagnosis and therapy

Seventy-one fetal blood samplings (FBS) were attempted from the intrahepatic portion of the umbilical vein (IHV) at 18–34 weeks; 54 were attempted primarily and 17 secondarily after a failed attempt at the placental cord insertion. Fetal blood was obtained in 89 per cent of the cases. Intravascular transfusion (IVT) was attempted on 31 occasions and successful in 24 (77 per cent). In all cases of failed sampling or transfusion via the IHV, prenatal diagnosis and/or therapy was accomplished using alternative procedures. On only one occasion was the procedure postponed. There were no losses or neonatal morbidity attributable to the procedure. FBS from the IHV may be considered as an alternative approach to sampling the placental cord insertion. It is recommended in cases where the approach to the placental cord insertion is difficult or hazardous.     

Prenatal diagnosis of alpha-1-antitrypsin deficiency by fetal blood sampling

Fetal blood sampling for the diagnosis of alpha-1-antitrypsin deficiency using protein isoelectric focusing was carried out in the period 1980–1985. The results of 25 cases from 18 mothers are reported. All had a previous history of a PiZ child affected by liver disease. The method was found to be technically satisfactory and the fetal results were subsequently confirmed in all 18 cases where follow-up was possible. The fetus was found to be PiZ in nine cases and all these pregnancies were terminated. Of the remaining pregnancies three cases aborted or were delivered prematurely and 13 proceeded to term without complications.     

Maternal cell contamination in cultured chorionic villi: Comparison of chromosome Q-polymorphisms derived from villi,fetal skin,and maternal lymphocytes

Maternal cell contamination of chorionic villi (CV) samples used for first trimester prenatal diagnosis can cause obvious and/or unrecognized diagnostic dilemmas. The purpose of this investigation is to assess the frequency of maternal cell contamination (MCC) in chorionic villus samples and to evaluate selected parameters which might predict where contamination is more likely to have occurred. Maternal lymphocytes, chorionic villi from ultrasonically directed transcervical catheter aspiration, and fetal tissue were obtained at 8–11 weeks gestation from 45 patients undergoing elective termination. Quinacrine (Q) banded metaphases were compared from duplicate direct preparations of chorionic villi; cultured chorionic villi, fetal fibroblast tissue cultures, and maternal lymphocyte cultures. Q-polymorphisms in metaphase chromosomes were 100 per cent concordant between fetal tissue and direct CV preparation. However, evidence for maternal cell contamination occurred in 13.1 per cent of cultured chorionic villi preparations where polymorphisms were found to be identical between maternal and cultured CV and both distinct from fetal tissue preparations. Where MCC was identified, it was noted that CV cell cultivation interval was prolonged (24.2±6.8 days) compared with non-contaminated cultures (14.1±4.4 days) (p <0.05). We conclude that maternal cell contamination is a significant problem with chorionic villus sampling. Where direct preparations are not employed or when cultures are ‘slow growing’, MCC may be a significant and unrecognized complication re: fetal diagnosis. Direct preparations, multiple cultures, quinacrine banding, and maternal Q-polymorphism comparisons can minimize diagnostic dilemmas secondary to maternal cell contamination. Q-polymorphism comparisons between maternal and fetal chromosomes should be included in all instances where cultured chorionic villi are utilized for fetal diagnosis and where direct preparations are not available.     

Experience with first trimester prenatal diagnosis of Menkes disease

We have performed 28 first trimester diagnoses for Menkes disease in 27 high risk pregnancies by direct copper measurement on chorionic villi (c.v.) Two male fetuses were found to be affected because of significantly increased copper content. In one male fetus a slightly increased copper content was observed indicating an exogenous copper contamination of the sample. This view was supported by normal results observed after abortion. Three out of 15 diagnostic c.v. samples with a female karyotype showed increased copper levels. In two of these cases, part of the copper content might have been released from the cannulae used for these particular biopsies. Histochemical visualization of copper accumulation in fixed chorionic villi of two affected fetuses and one female fetus was observed. [⁶⁴Cu]-uptake studies have been performed on 11 diagnostic and 10 control c.v. samples. As the control samples in some cases were found to incorporate more [⁶⁴Cu] than the corresponding diagnostic sample, this method cannot at present be used for diagnosis. Compiled results on newborn females gave evidence that two carriers expressed the paternal X-chromosome, and two carriers expressed the maternal X-chromosome in chorionic villi.     

Cardiac flow after fetal blood sampling in normally grown and growth-retarded fetuses

The objective of this study was to evaluate the effect of fetal blood sampling on cardiac flow velocity waveforms. Flow velocity waveforms were measured from the ascending aorta and pulmonary artery immediately before and after fetal blood sampling in 29 normally grown and 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were the peak velocity, the time to peak velocity, and the left and right cardiac output and their ratio. In normally grown fetuses, the peak velocity and right and left cardiac output values increased significantly after fetal blood sampling, while no significant changes were observed in the other indices considered. The gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling did not induce any significant increase in cardiac output or peak velocities, while in more than 50 per cent of the fetuses these Doppler indices decreased. The amplitude of the decrease was significantly related to the severity of acidosis in the umbilical vein. In conclusion, the cardiac haemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling.