Sonographic demonstration of fetal sacrococcygeal teratoma

Six cases of sonographically diagnosed fetal sacrococcygeal teratoma (SCT) are presented and illustrate the variable features of fetal SCT. The sonographic findings assisted the parents and perinatal team in making decisions, and in two of the cases the children survived after elective Cesarean section and prompt neonatal resection of the tumors. None of the patients showed signs of malignant degeneration of the teratoma or metastases. Fetal SCT no longer should be considered a uniformly fatal condition. The literature on sacrococcygeal teratoma detected after birth indicates that the mortality rate is correlated with the degree of extension of the tumor. Therefore, the classification of sonographically diagnosed fetal SCT according to its size and position is important for decisions regarding pregnancy management.     

Do racial differences exist in second-trimester maternal hCG levels? a study of 23 369 patients

In Down syndrome screening by maternal serum human chorionic gonadotropin (hCG) determination at 15, 16, 17, and 18 weeks of gestation, we prospectively examined 23 369 sera from white (21 549), North African (970), black African (525), and Asian (325) patients. When expressed as multiples of the median (MOM), no difference was observed between white, North African, and black African patients. However, higher serum hCG concentrations were noted in Asians, for whom we therefore recommend correction of hCG values before calculation of the risk of Down syndrome.     

Economic assessment of maternal serum screening for Down's syndrome using human chorionic gonadotropin

The effectiveness and costs of prenatal screening programmes for Down's syndrome using maternal serum markers will vary significantly depending on the biological cut-off values chosen in order to select women, at each maternal age, who will be sent for amniocentesis. On the basis of the first French prospective study of human chorionic gonadotropin (hCG) measurement in maternal serum, this paper shows that the screening protocol currently used in France, where hCG cut-off values are defined in order to offer amniocentesis to women of all ages with a 1 percent fetal risk of Down's syndrome, would detect 64·06 per cent of all cases of trisomy 21 at birth and would be highly profitable for the French social security system. On the basis of a representative sample of 100 000 pregnant women, the total costs of screening would reach $8 302 000 but would generate net potential savings of $32 186 000 in terms of life-long costs of care for trisomic 21 children which would be ‘avoided’ by termination of pregnancy following a positive diagnosis of Down's syndrome. Economic assessment shows that cost-benefit analysis would justify lower hCG cut-off values and a higher detection rate of fetal Down's syndrome (74·45 per cent) than the current French protocol. This paper concludes that it is ethical and value-laden issues, such as the consequences for women and couples of false positives and false negatives of screening, rather than economic and financial arguments that may set limits to the utilization of screening for Down's syndrome using maternal serum markers like hCG.     

Primary co-culture as a complementary approach to explore the diversity of bacterial associations in marine invertebrates: the example of <Emphasis Type="Italic">Nautilus macromphalus</Emphasis> (Cephalopoda: Nautiloidea)

The recent application of molecular tools to address associations between bacteria and marine invertebrates has provided access to an immense diversity of unidentified microbes resistant to cultivation. However, the role of bacteria as partners in animal physiology remains unclear and in most cases difficult to investigate in the absence of adequate condition of cell growth and proliferation. In this work, we studied the reservoir of microbes associated with the excretory organs of Nautilus macromphalus as a model. Using the bacterial 16S RNA gene as a marker, we compared three complementary approaches for bacterial detection: bacterial DNA extraction from N. macromphalus tissues (“molecular approach”), strain isolation to provide a bacterial culture collection (“microbiological approach”) and finally, maintenance of N. macromphalus excretory organ cells with associated bacteria (“cellular approach”). Our results stress the potential of the “cellular approach” as a promising new tool as it promotes the detection of as yet uncultured β-proteobacteria and spirochaetes associated with N. macromphalus, and serves as a foundation for future studies describing potential roles that these bacteria may play in Nautilus.     

Competition for food and other niche-related studies of three species of salt-marsh foraminifera

The niches of 3 species of salt-marsh foraminifera, Allogromia laticollaris, Rosalina leei, and Spiroloculina hyalina were assessed in the laboratory. The 3 species reproduce within the following ranges: temperature (10° to 33°C), salinity (12 to 45‰) and pH (5 to 10). Competition for food among the 3 species was evaluated. S. hyalina did not compete with other species. Intraspecific competition (crowding) appears to be an important factor limiting the reproduction of A. laticollaris. Crowding seems to have little effect on the other 2 species. The feeding of foraminifera is affected by the quality and quantity of food organisms. The feeding rate of the species tested is directly related to concentration within a range of 10² to 10⁶ cells fed. S. hyalina is a bacterial feeder. A. laticollaris is a rare species which may become locally abundant when dominant species are missing. S. hyalina is also a rare species, which can bloom where the density of bacteria is relatively high and in the absence of competing species. R. leei is a stable, conspicuous species, whose moderate numbers are relatively unaffected by physical stress and competition. Some new laboratory data on Ammonia beccarii were obtained so that this species could be compared with the other studied. Differences in niches are graphically presented.     

Application of mechanical shear in an internal-recycle for the enhancement of mesophilic anaerobic digestion.

A combination of bench- and full-scale studies were conducted to determine the effectiveness of high-intensity mechanical shear in an internal recycle loop to enhance mesophilic anaerobic digestion and the implications of this process for routine operations of a digestion system. During short-term batch digestion (56 hours), a 46% increase in biogas production was observed. However, it was found that the degree of digestion enhancement was sludge-specific, with increases in volatile solids destruction ranging from 16.6 to 110%. A full-scale demonstration showed increased total and volatile solids destruction of 22 and 21% for the primary digester and 17.2 and 11% for the secondary digester, respectively. The data also suggest that increased protein degradation is one of the major mechanisms associated with the observed increases in volatile solids destruction. The full-scale demonstration also determined that shear enhanced digestion can be operated without process upset, based on volatile fatty acid profile and headspace biogas composition (methane and carbon dioxide). Dewatering properties, as measured by polymer demand, deteriorated in the primary digester, but there was improvement in the secondary digester. High-intensity shear does not appear to enhance pathogen reduction based on total and fecal coliform bacterial enumeration.     

A single chorionic gonadotropin assay for maternal serum screening for Down's syndrome

A simple enzyme immunoassay measuring human chorionic gonadotropin in undiluted maternal serum has been developed in order to be used as a prenatal screening test for Down' s syndrome. A retrospective study of maternal serum sampled during pregnancies associated with trisomy 21 shows that with a 5% amniocentesis rate determined on a single test, the detection rate of trisomy 21 would be around two-thirds of the affected pregnancies. A prospective study of 9040 pregnant women under 38 years has confirmed the usefulness of the assay.