Early prenatal direct gene diagnosis of cystic fibrosis in a twin pregnancy and subsequent selective termination

We present a case of prenatal diagnosis of cystic fibrosis (CF) in one twin at 11–12 weeks of gestation. The parents had previously had two children, one of whom is alive and healthy and one who died of CF at the age of 2½ months. The parents were both known to be carriers of the ΔF508 mutation. Chorionic villus sampling (CVS) was performed and direct gene analysis showed that one fetus was homozygous for the ΔF508 mutation, while the other fetus did not have the mutation at all. Both fetuses had normal karyotypes. Selective termination was subsequently performed. The pregnancy continued without complications except for mild pre-eclampsia at term. The woman had a Caesarean section. The genetic diagnosis was confirmed after birth.     

Mosaic triple trisomy in amniocytes from a phenotypically and karyotypically normal fetus

We report the detection of a mosaic triple trisomy, 46, XY/49, XY, + 13, +20, +21, in two amniotic fluid specimens obtained from a pregnancy that yielded a normal infant. Traditional cytogenetic methods failed to detect the abnormal cell lineage in fetal blood, foreskin, amnion, umbilical cord, and three different biopsies of the chorion. In addition, fluorescence in situ hybridization study of cells from a buccal smear showed no evidence of cells with three copies of chromosome 20.     

Early transvaginal sonographic diagnosis of alobar holoprosencephaly

Holoprosencephaly is a cerebral anomaly resulting from incomplete cleavage of the primitive prosencephalon or forebrain. Early detection of this anomaly is very important since the most severe form is incompatible with life. The diagnosis also signals the need for a chromosomal determination since chromosomal abnormalities have been associated with this anomaly. An early diagnosis of alobar holoprosencephaly at 14 weeks' gestation, employing transvaginal sonography, is reported. Our findings are compared with prenatal transabdominal sonographic findings of holoprosencephaly which have been reported during the last decade in the literature.     

Ultrasonographic diagnosis of a fetal abdominal mass: A case of a mesenchymal liver hamartoma and a review of the literature

A case of a prenatally recognized hepatic mesenchymal hamartoma is presented and the literature reviewed. These tumors are benign and usually present in early infancy with symptoms that are related to the mass effect on adjacent organs. Radiologic methods used in the past to image this tumor include angiography and ultrasound. However, there is no specific radiologic finding, and, therefore, the diagnosis is usually made during surgery. Once the tumor is removed, the prognosis is generally good. With the increasing use of high resolution ultrasound in prenatal diagnosis, this rare tumor should be considered in the differential diagnosis of any multicystic mass found in the fetal abdomen. The recognition of a mass should then alert the physician to the need for early neonatal intervention.     

Heteropteran chemical repellents identified in the citrus odor of a seabird (crested auklet: Aethia cristatella): evolutionary convergence in chemical ecology

The exogenous application of chemical repellents is widespread in birds, but endogenous production is exceedingly rare. We herein report a new class of avian defensive compounds isolated from the feathers and volatile odor of the crested auklet (Aethia cristatella). Mass spectra indicate that n-hexanal, n-octanal, n-decanal, Z-4-decenal and a 12-carbon unsaturated aldehyde comprise the auklet odorant. Octanal and hexanal are also secreted in the repugnant metasternal gland emissions of heteropteran insects and are known to be potent invertebrate repellents. We suggest that the auklet odorant functions as an ectoparasite repellent and a signal of mate quality. This would represent a rare and direct link between vigor, quality and parasite resistance, one of several putative bases for mate selection. This is the first report of defensive compounds produced by a seabird or colonial bird and one of the few examples of chemical defense in a polar or subpolar marine vertebrate.     

Variation in prenatal cytogenetic diagnosis: Policies in 13 european countries, 1989–1991

The livebirth prevalence of autosomal chromosomal anomalies is determined by several factors, including maternal age distribution and the impact of prenatal cytogenetic diagnosis (PCD). The impact of PCD varies between countries, as the indications and the uptake vary. In a previous study we described differences in Down syndrome prevalence and the proportion of older mothers. We have now made a survey of the official PCD policies in 25 regions in 13 European countries for the period 1989–1991. In two countries, termination of pregnancy was not available. In the other 11 countries, international agreement existed on five indications: advanced maternal age, a previous child with a chromosomal anomaly, parents who are carriers of a balanced translocation, mothers who are carriers of an X-linked disorder, and malformations at ultrasound. The exact limit for advanced maternal age varied from 35 to 38 years. There was a considerable variation for the indications advanced paternal age, amniocentesis for AFP or DNA, parental anxiety, a previous child with a congenital anomaly, abnormal maternal serum markers, and exposure to radiation/chemotherapy. The PCD uptake for mothers above the maternal age limit varied from 10 to 88 per cent. International harmonization of the indications for PCD is not considered feasible at present, because of the rapid changes in PCD policies even within countries.     

A large retinoblastoma detected in a fetus at 21 weeks of gestation

The facial tumour described here is the first reported case of a large retinoblastoma detected early in pregnancy and adds another item to the differential diagnosis of facial tumours visualized by prenatal ultrasound examination. Ultrasound examination of the fetal eyes can be offered in cases of retinoblastomas where prenatal DNA diagnosis is otherwise impossible.     

The relationship between adaptation and mitigation in managing climate change risks: a regional response from North Central Victoria,Australia

This two-part paper considers the complementarity between adaptation and mitigation in managing the risks associated with the enhanced greenhouse effect. Part one reviews the application of risk management methods to climate change assessments. Formal investigations of the enhanced greenhouse effect have produced three generations of risk assessment. The first led to the United Nations Intergovernmental Panel on Climate Change (IPCC), First Assessment Report and subsequent drafting of the United Nations Framework Convention on Climate Change. The second investigated the impacts of unmitigated climate change in the Second and Third IPCC Assessment Reports. The third generation, currently underway, is investigating how risk management options can be prioritised and implemented. Mitigation and adaptation have two main areas of complementarity. Firstly, they each manage different components of future climate-related risk. Mitigation reduces the number and magnitude of potential climate hazards, reducing the most severe changes first. Adaptation increases the ability to cope with climate hazards by reducing system sensitivity or by reducing the consequent level of harm. Secondly, they manage risks at different extremes of the potential range of future climate change. Adaptation works best with changes of lesser magnitude at the lower end of the potential range. Where there is sufficient adaptive capacity, adaptation improves the ability of a system to cope with increasingly larger changes over time. By moving from uncontrolled emissions towards stabilisation of greenhouse gases in the atmosphere, mitigation limits the upper part of the range. Different activities have various blends of adaptive and mitigative capacity. In some cases, high sensitivity and low adaptive capacity may lead to large residual climate risks; in other cases, a large adaptive capacity may mean that residual risks are small or non-existent. Mitigative and adaptive capacity do not share the same scale: adaptive capacity is expressed locally, whereas mitigative capacity is different for each activity and location but needs to be aggregated at the global scale to properly assess its potential benefits in reducing climate hazards. This can be seen as a demand for mitigation, which can be exercised at the local scale through exercising mitigative capacity. Part two of the paper deals with the situation where regional bodies aim to maximise the benefits of managing climate risks by integrating adaptation and mitigation measures at their various scales of operation. In north central Victoria, Australia, adaptation and mitigation are being jointly managed by a greenhouse consortium and a catchment management authority. Several related studies investigating large-scale revegetation are used to show how climate change impacts and sequestration measures affect soil, salt and carbon fluxes in the landscape. These studies show that trade-offs between these interactions will have to be carefully managed to maximise their relative benefits. The paper concludes that when managing climate change risks, there are many instances where adaptation and mitigation can be integrated at the operational level. However, significant gaps between our understanding of the benefits of adaptation and mitigation between local and global scales remain. Some of these may be addressed by matching demands for mitigation (for activities and locations where adaptive capacity will be exceeded) with the ability to supply that demand through localised mitigative capacity by means of globally integrated mechanisms.     

PCBs and other organochlorines in human tissue samples from the Welsh population: II--Milk

Polychlorinated biphenyl (PCB) and SigmaDDT (i.e. p,p'-DDT + p,p'-DDE = p,p'-DDD) concentrations were determined from the analysis of 115 Welsh breast milk samples collected in 1990 and 1991. Fifty PCB congeners were screened, of which 24 were identified in most samples. The PCB congener pattern was consistent between individual milk samples, with IUPAC congeners 28, 138, 153 and 180 being the most abundant and accounting for an average of 50% of the SigmaPCB concentrations determined. PCB concentrations varied between 2 and 70 ng g(-1) whole milk, were positively correlated with age, and negatively correlated with the total lactation period and with the percent lipid content of the milk. PCB pattern distributions differed between milk and adipose tissue samples. Human milk had a higher proportion of tri- (18 and 28), tetra- (44, 52 and 66) and pentachlorinated biphenyls (101) compared to human adipose tissue. SigmaDDT concentrations ranged from 0.3 to 71 ng g(-1) of whole milk, with p,p'-DDE contributing towards an average of 92% of the SigmaDDT concentrations. SigmaDDT levels were also positively correlated with age and negatively associated with the lactation period, though these correlations were rather weak. No significant differences in the SigmaPCB and SigmaDDT concentrations were noted between milk samples from donors living in rural and urban locations, or between the subjects' body weight, smoking habits or diet.