Chorionic mosaicism: Association with fetal loss but not with adverse perinatal outcome

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.     

Screening for Down's syndrome in older women based on maternal serum alpha-fetoprotein levels and age: Preliminary results

We report the results of screening for Down's syndrome (DS) in older women using published rate schedules based on maternal serum alpha-fetoprotein (MSAFP) and age. Five hundred and seventeen patients aged 35 years and older, who were referred for a mid-trimester genetic amniocentesis, were first tested for MSAFP and then underwent an amniocentesis. Individual risks for DS, combining MSAFP and age, were derived using three different published rate schedules. Theoretical selection for amniocentesis was made using the cut-off level of the average collective risk for a 35-year-old woman (1:380 at live birth or 1:270 at amniocentesis). Six affected pregnancies (five with DS and one with trisomy 18), which were diagnosed prenatally, were all found to be at a higher risk than the specified cut-off. These cases would have been diagnosed in any event, using any of the published rate schedules. According to these rate schedules, between 39 and 45 per cent of the patients would be in the lower risk group and therefore would have been counselled not to undergo amniocentesis. Further studies should be conducted in order to reach conclusive screening policies for DS in older women.     

Chorioangioma: A new inclusion in the prospective and retrospective evaluation of elevated maternal serum alpha-fetoprotein

Two cases are presented which illustrate the association of elevated maternal serum alpha feteprotein (MSAFP) levels and chorioangiomas. These cases emphasize the importance of ultrasound study of the placenta in MSAFP elevation evaluation. In addition, placentas from pregnancies with otherwise unexplained MSAFP elevations should be submitted for pathologic study. A definitive retrospective diagnosis may thus be provided.     

Racial differences in maternal serum human chorionic gonadotropin and unconjugated oestriol levels

We assayed maternal serum samples from 134 black and 268 white women from 16 to 18 weeks of gestation for intact human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3). Serum from women with high ( ⩾ 2·5 MOMs) or low (risk for Down syndrome ⩾ 1/365) maternal serum alpha-fetoprotein (MSAFP) levels were excluded. After correcting for maternal weight, we found that median hCG levels were 16 per cent higher in black women but uE3 levels were not significantly different. These results confirm three other studies for hCG and one study for uE3. Corrections are recommended for both maternal serum hCG and AFP before calculating the risk for Down syndrome in black women.     

Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed

This pilot study examined five commercial salmon feeds, four farmed salmon (one Atlantic, three chinooks) and four wild salmon (one chinook, one chum, two sockeyes) from the Pacific Coast for PCBs (112 congeners), polybrominated diphenylethers (PBDEs - 41 congeners), 25 organochlorine pesticides (OPs), 20 polycyclic aromatic hydrocarbons (PAHs), and methyl and inorganic mercury. The farmed salmon showed consistently higher levels of PCBs, PBDEs, OPs (except toxaphene) than the wild salmon. The mean concentrations in pg/g were 51,216 vs 5302 for total PCBs; 2668 vs 178 for total PBDEs; 41,796 vs 12,164 for total OPs (except toxaphene). The farmed salmon levels are likely a consequence of the elevated level of contamination found in the commercial salmon feed (mean concentrations in pg/g were 65,535 for total PCBs; 1889 for total BPDEs; 48,124 for total OPs except toxaphene). Except for a single high wild chinook value, PAHs were highest in the feed samples followed by the farmed fish and the three other wild fish. The Bio-Oregon-1996 feed of hatchery origin showed a level of PAHs ten times higher than any other feed. The genotoxic implications of such a high PAH level are considered for juvenile chinook salmon. Toxaphene and methyl mercury concentrations were not notably different between the wild and farmed salmon. There was no clear low contaminant brand of salmon feed. The human health implications of eating farmed salmon are considered from the perspective of the current WHO and Health Canada (2000) tolerable daily intake (TDI) values for PCBs. Based on a TDI of 1 pg TEQ/kg bw/day, this analysis indicated a safety concern for individuals who on a regular weekly basis consume farmed salmon produced from contaminated feed.     

Prenatal diagnosis of cytomegalovirus (CMV) infection: A preliminary report

Eight patients were referred for prenatal diagnosis for suspected fetal cytomegalovirus infection (CMV): six for documented first-trimester infection and two for abnormal ultrasound evaluation suggestive of fetal infection. Three methods of diagnosis were employed: (1) amniotic fluid viral cultures and CMV-specific IgM in fetal serum; (2) amniotic fluid cultures and detection by polymerase chain reaction amplification of CMV-specific DNA in chorionic villi; and (3) detection of CMV-specific DNA in villus samples only. Amniotic fluid cultures detected all cases of infection, but CMV-specific IgM was not a reliable indicator of infection in any case. DNA analysis correlated well with both culture results and clinical outcome.     

DIE‐OFF OF PATHOGENIC E. COLI O157:H7 IN SEWAGE CONTAMINATED WATERS1

E. coli O157:H7 is a pathogen that can be present in sewage contaminated waters. This organism poses a health risk for humans who come in contact with these waters via drinking, swimming, or shellfish consumption. A risk assessment model is needed to evaluate or quantify this risk. One possibility is the use of a computer model to simulate the fate and transport of E. coli O157:H7 downstream from a discharge point [e.g., a separate sanitary sewer overflow (SSO)]. However, this computer model would require input data regarding characteristics of this organism, which have not been previously available. One necessary input parameter is the rate at which die off of this organism occurs in a stream or river environment. Several studies were conducted to evaluate the die‐off rate of E. coli O157:H7 in an SSO impacted stream. Indicator bacteria (total coliforms, E. coli, and enterococci) were evaluated simultaneously. The results suggest that E. coli O157:H7 is not persistent — decay rates are high relative to the indicator bacteria. However, the decay plots suggest a biphasic response: initial decay is rapid, followed by an attenuated, slower decay. Hence traditional simulation methods using a single, first‐order decay rate may be inaccurate.     

Early genetic amniocentesis and its relationship to respiratory difficulties in paediatric patients: A report of findings in patients and matched controls 3–5 years post-procedure

This study evaluates the long-term pulmonary complications of 25 children from a prospective, matched-control, pilot study evaluating short-term complications of early (11–14 weeks' gestation) versus traditional (15 weeks' gestation and later) genetic amniocentesis. Five children in the early amniocentesis group were found to have various respiratory difficulties, a morbidity rate comparable to that of paediatric patients in the general population. These data identify the need for larger, multicentre trials.