Estimating the risk of a fetal autosomal trisomy at mid-trimester using maternal serum alpha fetoprotein and age: A retrospective study of 142 pregnancies

Risks appropriate for mid-trimester prenatal screening for autosomal trisomies have been estimated from a combination of maternal age and maternal serum (MS) alpha-fetoprotein (AFP) levels at 16–20 weeks gestation. Published data on the frequency of Down's syndrome births relative to maternal age were modified to include the additional age-related frequency of trisomy 18 and trisomy 13 cases to provide an overall risk for an autosomal trisomy at midtrimester. MSAFP results from a retrospective study of 142 affected (114 trisomy 21, 19 trisomy 18, and 9 trisomy 13)and 113 000 unaffected pregnancies were converted to multiples of the appropriate gestational median (MOM). The AFP levels in the autosomal trisomy pregnancies were found to be significantly reduced at 0.72 MOM of the unaffected pregnancies. Risks (likelihood ratios) were derived from the overlapping log Gaussian distributions for affected and unaffected pregnancies and combined with maternal age risks to give the overall odds of an affected pregnancy. A mid-trimester cut-off risk of 1:280 gave an estimated 37 per cent detection rate for autosomal trisomies in the west of Scotland population for a follow-up (false-positive) rate of 6.6 per cent. These figures compare with a 30 per cent detection and 6.7 per cent false-positive rate if age 35 years and over is used as the sole criterion for selection of at-risk pregnancies.     

A simple random path method for the analysis of flow networks

The path of a particle through an ecosystem is modelled as a Markov chain. For a given flow network, powers of the transition matrix are used to calculate the distribution of the particles over the network after each transition. The method may be applied for the definition and calculation of trophic levels in food webs. The algorithm yields the trophic level distribution of species, the species composition of trophic levels, and the path length distribution of output flows. In addition, the network can be described as a linear chain, with the throughflows at each step identified. Data from several ecosystems are analyzed by the method, showing that surprising insights may result.     

Prenatal sonographic signs of possible fetal genital anomalies

The sonographic markers of female and male external genitalia have been documented in early and late gestation. The aim of the present study was to report our experience of possible sonographic markers of fetal genital anomalies. Sonography was performed with a vaginal probe in early gestation and an abdominal sector scanner in advanced gestation. The following genital anomalies were observed: hypospadias, epispadias, ambiguous genitalia, and testicular feminization or Smith-Lemli-Opitz syndrome. It is therefore concluded that prenatal diagnosis of some genital anomalies is now possible.     

Oligohydramnios with amnio-chorionic separation at 15–16 weeks' gestation

Nine patients with oligohydramnios and amnio-chorionic separation were identified out of 7000 women who underwent a vaginal ultrasound examination at 15–16 weeks' gestation. Oligohydramnios was defined as a reduced amount of amniotic fluid, a distance of more than 1 cm between the chorion and amnion, and a good turgor of the amnion without floating membranes or intrauterine sheets. Fetal malformations were observed in all nine cases. In four of six fetuses where chromosomal analysis was available, an abnormal karyotype was found. It is concluded that oligohydramnios in the early second trimester is associated with fetal abnormality.     

Uterine cavity lavage: Adding fish to conventional cytogenetics for embryonic sexing and diagnosing common chromosomal aberrations

This study was undertaken to examine the efficacy for early prenatal diagnosis of uterine cavity lavage at the level of the internal os and to assess the rate of maternal contamination. In phase I, uterine cavity lavage was performed in 38 women scheduled for pregnancy termination between 6 and 12 weeks. In addition to short- and long-term cultures, one-colour FISH (fluorescence in situ hybridization) with Y and X probes was used for fetal sexing. Two-colour FISH was used in all known male fetuses for the assessment of maternal contamination. In phase II, lavage was performed on 16 women. Fetal sex was diagnosed with direct labelled X and Y probes and common numerical chromosomal aberration was attempted with 18 and 21 direct labelled probes. Fetal sexing was successful in all cases in phases I and II. Out of 34 patients in which tissue was obtained, only FISH was done in six. Long-term cell cultures were successful in the other 28 cases, but complete karyotyping in 19 (56 per cent). No chromosomal aberration was found with the direct labelled probes 18 and 21 in FISH. Maternal contamination was assessed to be 5–10 per cent. This simple and easy-to-master technique is very effective in obtaining fetal cells early in pregnancy for genetic diagnosis, especially by FISH. However, the safety of the procedure must be tested in ongoing pregnancies.     

Emergency preparedness consultants at the local government level: the Israeli experience

This study evaluates the effectiveness of the Municipal Emergency Consultation project in eight Israeli local authorities. The initiative centres on the appointment of independent emergency preparedness consultants entrusted with tailoring an emergency preparedness package to suit the specific needs of each locality. Regarding emergency preparedness improvements, in all of the municipalities examined, a concept of municipal emergency operation was consolidated and the derived emergency plan tested. Emergency work processes were structured and service‐level agreements reached between municipality departments. Where necessary, a‐linear patterns of municipal functioning in an emergency were established. Concerning a ‘spillover’ of emergency preparedness improvements into routine operations, and a ‘spillover’ of routine management improvements into local emergency preparedness, two municipalities near Gaza, which typically function in an emergency routine, saw a significant ‘spillover’ of emergency preparedness into routine functioning. In other localities, local managers chose to improve a number of municipal structures and procedures in times of routine functioning, which are also related to the functioning of the municipality during an emergency.