Prognosis of fetuses with a cystic hygroma

This paper reports our experience with 55 fetuses identified in utero to have a cystic hygroma. The outcome of fetuses with an isolated cystic hygroma, cystic hygroma with non-immune hydrops, and cystic hygroma with multiple anomalies was evaluated. Approximately two-thirds of karyotypes were aneuploid, and a strong association of septation and aneuploidy existed. Only five cases, four of which had isolated hygromas, came to term and resulted in live births. Two of these involved small non-septated lesions which resolved in utero.     

The value of routine cervical cultures before transcervical chorionic villus sampling

In 226 women requesting chorionic villus sampling (CVS), routine cervical cultures were obtained before the procedure. Transcervical CVS was performed irrespective of the test results. The prevalence of potential pathogens in cervical cultures at our institution is low. Beta haemolytic Streptococcus was cultured in 3 per cent of the women. No pathogenic microorganisms were isolated in 64 per cent of the women. There was no relationship between culture results and the outcome of pregnancy. These observations suggest that adequate antiseptic cleansing of the genital tract is a suitable approach and there is no need to routinely perform cultures before CVS.     

Ultrastructure of first trimester chorionic villi with regard to the prenatal diagnosis of genodermatoses

Hopes are held out for chorion villus sampling, a technique which is gaining more and more importance for the first trimester prenatal diagnosis of chromosomal aberrations and metabolic abnormalities. A variety of inherited skin diseases can be diagnosed postnatally and prenatally (in the second trimester) by ultrastructural diagnostic markers. For evaluation of prenatal diagnosis in the first trimester, we investigated chorionic villi derived from the trophoblast layer of the early pregnancy by light microscopy and conventional electron microscopy. The ultrastructure of the cellular layers covering the villi, i.e., the inner cytotrophoblast and the outer syncytiotrophoblast, as well as that of the connective tissue of the inner extraembryonic mesoderm, are thoroughly described in relation to the ultra-structural changes in certain genodermatoses including epidermolyses and keratinization disorders. We found that chorionic villi have only a few of the characteristics differentiated in skin, and none of the structures which are relevant to the diagnosis of genodermatoses. In our view, the ultrastructural approach is not suitable for first trimester prenatal diagnosis of genodermatoses in chorionic villi.     

Maternal cell contamination in chorionic villus samples assessed by direct preparations and three different culture methods

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.     

Prenatal ultrasound diagnosis of rhizomelic chondrodysplasia punctata in a primigravida

Rhizomelic chondrodysplasia punctata (RCDP) is a sublethal autosomal recessive disorder characterized by skeletal dysplasia, microcephaly, mental retardation, congenital cataracts, joint contractures, skin changes, and failure to thrive. Prenatal ultrasound diagnosis has been reported during the second trimester of pregnancy. Prenatal diagnosis is also possible from the first trimester onwards by demonstration of peroxisomal dysfunction in cultured chorionic villous or amniotic fluid cells. In all cases reported hitherto, the prenatal diagnosis was established after the birth of a previous affected child. In contrast to these studies in pregnant multiparous women at risk for RCDP, we report on the first case of prenatal ultrasound diagnosis of RCDP at 19 weeks' gestation in a primigravida. In addition, a complex cardiac malformation associated with hypoplasia of the thymus (DiGeorge anomaly) is described.     

Cytogenetic diagnoses after chorionic villus sampling are less reliable in very-high- or very-low-risk pregnancies

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.     

Interactive effects of salinity,temperature and chronic exposure to oil on the survival and developmental rate of embryos of the estuarine killifishFundulus heteroclitus

The combined effect of salinity, temperature and chronic exposure to water-soluble fractions (WSF) of a No. 2 fuel oil on the survival and development rate of embryos ofFundulus heteroclitus Walbaum are described. The embryos were exposed at 3 salinities (10, 20, 30 S) and 3 temperatures (20°, 25°, 30°C) to 3 different oil concentrations (15, 20, 25% WSF, equivalent to approx 0.28, 0.38 and 0.47 ppm total naphthalenes) and to one control without oil. The results were analyzed by responsesurface methodology. The lowest oil concentration was only mildly toxic to embryos under optimal salinity/temperature conditions, while the highest was extremely toxic in all factor combinations. Under optimal conditions, only the highest oil concentration resulted in more than 50% mortality. Under suboptimal conditions, especially high and low temperatures, all 3 oil concentrations caused greater than 50% mortality. The interactive effect of salinity and temperature on survival was greatest at the lowest oil concentration. Temperature had a marked effect and salinity only a slight effect on the developmental rate of the embryos. Exposure to the low oil concentration tended to increase the temperature sensitivity of developmental duration slightly. Generally, exposure to oil decreased the time interval between fertilization and hatching.     

Rearing of prawn larvae,Penaeus japonicus,fed soy-cake particles and diatoms

Soy cake^* was homogenized and filtered through an 80 mesh net to produce small, detritus-like particles. The effect of soy-cake particles, an artificial detritus, on the survival and growth of Penaeus japonicus Bate zoea was then tested. The soy cake was considered to be effective for survival and growth of the zoea. The best survival rate, 85.9%, was obtained in a tank receiving soy cake in quantities of 0.16 mg/zoea/day. An experiment was also performed to compare three kinds of food: particles of soy cake alone, diatoms (Chaetoceros rigidus) alone, and a half and half mixture of the two. The best growth, 2.49 mm, and the highest survival rate, 79.1%, were found in larvae fed the mixture of soy-cake particles and diatoms. The results thus seem to demonstrate that particles of soy cake could be usefully applied to the mass-culture of the penaeid prawn.     

Human impact on the Falkland Islands environment

Summary A historic analysis of human-initiated influences on the Falkland Islands ecologies is presented. Ecosystems were extensively altered by the destruction of seal and penguin communities in the late eighteenth and nineteenth centuries; and by the introduction of domesticated animals and exotic plants, the proliferation of fires, and the hunting to extinction, or near extinction, of certain animals. The harsh Falklands climate has permitted only limited recovery from some of these ravages. No island ecosystems, however remote, are spared the effects of economic and political changes influencing the rest of the world.He has published a previous article on island ecologies inThe Environmentalist (1992).     

Managerial conceptions of environmental responsibility

Summary In order for business and industry to exercise environmental responsibility in their daily operations and practices, it is necessary for company personnel at all levels to be aware of and committed to the implementation of environmental policies. This study used a phenomenographic approach to explore different ways in which company executives understand and apply environmental responsibility in their managerial roles. Ten senior managers located in three large industrial companies were interviewed and encouraged to express their own interpretation of the phenomenon of environmental responsibility. Four distinct conceptions emerged from the data which differ according to the preferred methods of expressing environmental responsibility within a business setting and the perceived motivations underlying corporate environmental action.Environmental responsibility may be conceived as: (1) an internal proactive undertaking by the company; (2) a reactive response to external community pressures; (3) a negotiated responsibility based on balance and compromise between competing demands; or (4) a collective responsibility involving cooperation amongst companies, government and the wider community. These findings provide a realistic perspective on the phenomenon of management behaviour towards the environment. They form the basis for development of education programmes which will assist managers to adopt and implement environmentally responsible practices within their companies. Further research to extend this knowledge base is recommended.