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991.
R. J. Wapner MD J. L. Simpson M. S. Golbus J. M. Zachary D. H. Ledbetter R. J. Desnick S. E. Fowler L. G. Jackson H. Lubs R. J. Mahony E. Pergament G. G. Rhoads J. D. Shulman F. De La Cruz 《黑龙江环境通报》1992,12(5):347-355
Cytogenetic data from the United States NICHD collaborative study of chorionic villus sampling (CVS) were used to evaluate the clinical significance of chorionic mosaicism. The 10 754 patients with normal cytogenetic results were compared wtih 108 patients (1.0 per cent) with placental mosaicism and 181 patients (1.6 per cent) with pseudomosaicism. Of the pregnancies intended to continue, the pregnancy loss rate was significantly greater in patients with placental mosaicism than in the cytogenetically normal cohort (8.6 vs. 3.4 per cent, p <0.05). However, there was no difference in the frequencies of abruptio placenta, preterm labour or delivery, small-for-gestational-age newborns, pregnancy-induced hypertension, or neonates with Apgar scores less than 7. 相似文献
992.
First trimester fetal diagnosis was established in 100 pregnancies at risk by transabdominal chorionic villus sampling (TA-CVS). Forty-eight per cent of the women were 35 years or more at the time of sampling. Using the double needle technique, both the aspiration and the diagnostic success rate were 100 per cent. The mean amount of villi aspirated was 28·2 mg (10–50 mg). The mean needle time was 3 min. Vaginal spotting appeared in 2 per cent of the women. Four women had therapeutic abortion due to abnormal findings and one for social reasons. Three fetuses with normal karyotypes were lost. Excluding the therapeutic abortions, the fetal loss rate was 3±2 per cent. The fetal loss rate in the amniocentesis control group (n = 200) was 3±6 per cent. The cytogenetic diagnosis was carried out by the direct preparation technique as well as by chorion villus cultivation. All karyotypes were confirmed by lymphocyte cultures from umbilical cord blood or heel blood from the newborn or from aborted fetal tissue. Transabdominal CVS is deemed a safe and easy tool for achieving chorionic villi in the first trimester. 相似文献
993.
Presumptive maternal cell contamination (MCC) was monitored in identified male cases during cytogenetic comparison of direct techniques and three different culture regimes from 140 thoroughly dissected chorionic villus samples. Of the 66 identified male cases, 11(16·7 per cent) showed MCC, the mean number of cells examined per case being 8·2 (direct) and 14·5 (cultures); in the direct preparations only one of a total of 457 cells examined was female, while preparations from cultures revealed MCC in 11 cases. Four of these had MCC in more than one culture regime and four had only a single female cell. The results showed that (1) dependence on the culture system alone would have given a diagnosis based on maternal cells in one (1·5 per cent) male case, thus underlining the danger of this approach (a similar undetected rate of misdiagnosis being expected in the female cases) and (2) MCC was significantly lower in cultures grown in Chang medium as compared with the other two regimes, McCoy's 5A + 15 per cent fetal calf serum and 1 per cent Ultroser G, and McCoy's 5A + 25 per cent fetal calf serum, the latter expressing the highest level of MCC. 相似文献
994.
Julie S. Fryburg Miriam S. Dimaio Teresa L. Yang-Feng Maurice J. Mahoney 《黑龙江环境通报》1993,13(6):481-494
Thirty-nine (2.3 per cent) of 1724 chromosome studies from diagnostic chorionic villus samplings (CVS) done between 1983 and 1990 showed either level III (true) mosaicism (1.2 per cent) or level II (pseudo-) mosaicism (1.1 per cent) for chromosomal aneuploidy. Follow-up information on these 39 pregnancies was collected from questionnaires to families, paediatricians, and obstetricians. For all cases in which the pregnancy was continued and further testing was accomplished, the mosaicism was felt to be confined to the placenta. As compared with a control group of pregnancies evaluated by CVS with normal karyotypes, there was no increased incidence of pregnancy loss, congenital malformations, or developmental delay in the infants. Although intrauterine growth retardation occurred in several of the level III mosaic cases, adequate catch-up growth has been demonstrated. 相似文献
995.
PD Dr Ingo Kennerknecht Gotthold Barbi Michael Wolf Mahmoud Djalali Dieter Grab Rainer Terinde Walther Vogel 《黑龙江环境通报》1993,13(10):929-944
An increasing number of cytogenetic prenatal diagnoses are performed on chorionic villus samplings. The accuracy of this method is influenced by chromosomal mosaicism, mostly confined to direct preparation methods. Especially those investigators who have experienced false-negative and false-positive findings propagate the combined use of direct and culture methods. Yet large collaborative studies have shown that in approximately two-thirds of diagnostic cases only one procedure is applied. Moreover, the accuracy of a cytogenetic investigation depends not only on the ontogenetic origin of the tissues investigated, but also on interacting factors such as the ‘a priori risk’ and the ‘predictive value of a cytogenetic finding’. On this basis a differentiated prenatal diagnostic procedure is discussed, including either sole short-term culture (STC), combined STC and long-term culture (LTC), primary amniocentesis (AC), or primary percutaneous umbilical blood sampling (PUBS). The predictive value of the cytogenetic diagnosis from CVS varies significantly dependent on the a priori risk of a chromosome aberration and, in the case of an abnormal karyotype, on the specific chromosome involved. A non-mosaic and ‘non-lethal’ trisomy detected in STC is highly representative of the embryo/fetus, but there are exceptions of limited predictive value, e.g., trisomy 18. Guided by the strategy of an optional follow-up by LTC, AC, or PUBS in 1317 successive CV samplings, we are not aware of a false-negative diagnosis, but probably had one false-positive diagnosis: 47,XXY after STC; 46,XY after LTC. When referring to the rate of fetuses with an unbalanced karyotype expected in the different indication groups, a relative increase of false-positive findings in the very-low-risk group (maternal age ⩽35 years of age) and of false-negative findings in the very-high-risk group (abnormal ultrasonographic findings) of pregnant women when only performing CVS becomes obvious. Because of this dilemma, AC or—especially in the latter group—PUBS might be primarily offered to these indication groups instead of CVS. 相似文献
996.
结合实际工作经验,分析研究了环境监测中油的采样受采样体积、深度以及布点的影响。认为计算含油量时应考虑水域的总体积、采样体积、水体表面积等,这样才能较准确地估算受污水域中的含油量。 相似文献
997.
Wichmann H Sprenger R Ehlers N Bahadir MA 《Environmental science and pollution research international》2005,12(4):227-232
Background, Aims and Scope Releasing agents, applied in the aluminium diecasting process, usually consist of water, oils, waxes, polysiloxanes, as well
as of a set of additives like emulsifiers, corrosion inhibitors, and biocides. During spray application and part release,
gases and aerosols are emitted into workplace air. The chemical compositions of these emissions are determined by the components
of the releasing agents and their reaction products formed during thermal stress of more than 700 °C. In the frame of the
joint project, the analytical tasks were to develop an appropriate sampling strategy for this production environment, to draw
conclusions about the occurrence of hazardous chemicals from production plant studies and from laboratory-scale thermolysis
experiments, and to determine the biodegradability of customary releasing agents.
Methods During realistic test production, active air sampling was performed in a production hall using different adsorption materials.
Cotton fabric sheets were positioned in the production area as passive samplers. Thermolysis experiments were performed at
600 °C with sealed quartz ampoules. The biodegradability of different releasing agents was determined according to German
industry standard DIN 51828 (2000). For analyses, GC/MS (headspace), FTIR, HPLC, IC, and ICP-OES techniques were applied.
Results and Discussion The substance spectrum, which was found in workplace air, was dominated by saturated and non-saturated aliphatic hydrocarbons.
Besides these, alcohols, alkyl phenols, xylenes and other benzene derivatives, aldehydes, glycols, carboxylic acid esters,
and amides were present. The German limiting value of 40 mg/m3 of complex hydrocarbon mixtures in a diecasting workplace atmosphere
was clearly under-run. Total hydrocarbon contents ranged between 2.7 and 6.3 mg/m3. Five different PAH were found in the air
close to the diecasting machine, with maximum concentrations between 0.05 and 3.06 μg/m3. Concentrations of nonylphenols ranged
from 10 to 200 μg/m3, and those of triethanolamine from 20 to 30 μg/m3. From 17 elements analyzed, only B, Fe, P, S, Si, and
Ti were emitted in small amounts. It was striking that the PAH patterns resulting from thermolysis experiments were quite
the same compared to those determined during the diecasting process. An influence of water and of Fe/Al on the composition
of the thermolysis products could mostly be shown. The degrees of biodegradation of three releasing agent extracts after 21
days were 21%, 29%, and 55%, respectively.
Conclusion A sampling strategy was developed, which allows an emission assessment for the industrial process of aluminium diecasting.
It enabled one to control limiting values, to characterise a wide variety of compounds emitted, and to identify and quantify
relevant pollutants. Only a few hazardous substances could be detected during the exemplary use of one releasing agent within
the compounds emitted into workplace air. Indications were found, that the prediction of the formation of harmful substances
from releasing agent components should be possible via thermolysis experiments. The biodegradability test can serve to assess
the expenditure of disposal of the usual leakage run-off of excess agent during production.
Recommendation and Outlook Investigations on further differently composed releasing agents, e.g. powders, would be desirable. A substitution of nonylphenol
ethoxylates by less harmful components would surely be an improvement of a releasing agent with regard to work safety and
health care, because of avoiding the emission of toxic and endocrine active nonylphenols. The surprisingly wide range of biodegradability
of the investigated releasing agents points to an optimization potential, that has obviously not yet been considered. 相似文献
998.
999.
1000.
Sirpa Herve Harry F. Prest Pertti Heinonen Tarja Hyötyläinen Jaana Koistinen Jaakko Paasivirta 《Environmental science and pollution research international》1995,2(1):24-30
Semipermeable membrane sampling devices (SPMDs) and caged lake mussels (Anodonta piscinalis) were simultaneously deployed at four lake watercourse sites in Central Finland four weeks in August 1992. This study was
part of the regular annual monitoring of the organochlorine compounds (OCC) in pulp-mill recipient watercourses of Finland
with bivalves. Chlorohydrocarbons (CHCs), chlorophenol compounds (PCPs), chloroanisoles (PCAs) and chloroveratroles (PCVs)
were analyzed from lipid extract of mussels and from the synthetic triolein lipid of the SPMDs. Hexane-diethyl ether (9:1,
v/v) dialysis using polyethylene membrane was applied in dean up of the SPMD lipids and, for comparison, to six sets of the
mussel fat. Dialysis recovered CHCs but not PCPs from the mussel fat. CHCs, PCPs, PCAs and PCVs were all recovered in dialysis
of the SPMD lipid. Handling of SPMDs in the transport and deployment operations caused significant OCC contamination for the
blank SPMDs. Similar trends were revealed in the OCC profiles for mussels ans SPMDs. An exception was the lack of PCPs appearing
in SPMDs that did appear in mussels and in a complementary manner the appearance of the PCAs and PCVs in SPMDs. 相似文献