True trisomy 15 mosaicism,detected by amniocentesis at 12 weeks of gestation and fetal echocardiography

A case of mosaicism of trisomy 15, with two-thirds of the cells trisomic, was detected at 12 weeks of gestation in amniotic fluid cell cultures obtained with the filtration technique. Ultrasound examination at 13 weeks showed a nodule protruding into the amniotic cavity which was speculated to be remnants of a co-twin, causing the trisomic cell line. At 20 weeks of gestation, a malformation scan (level III) was normal, but supplementary fetal echocardiography revealed a severe cardiac defect (mitral atresia and a ventricular septal defect). Fetal lymphocytes obtained by cordocentesis showed trisomy 15 mosaicism, but only in 5 per cent of the mitoses. After termination, the same percentage of trisomy 15 mosaicism was found in cells from skin and tendon as in the original early amniocentesis. No sign of earlier twinning was found in the placenta or membranes. We conclude that mosaicism in early amniotic fluid obtained by the filter technique in this case reflected the true karyotype accurately and that supplementary echocardiography added significantly to the interpretation of the clinical implications.     

Assessing the toxicity and teratogenicity of pond water in north-central minnesota to amphibians

BACKGROUND: Incidence of amphibian deformities have increased in recent years, especially in the northern region of the United States. While many factors have been proposed as being responsible for generating deformities (e.g., contaminants, ultraviolet radiation [UV], parasites), no single cause has been definitively established. METHODS: To determine whether waterborne chemicals are responsible for amphibian deformities in ponds in north-central Minnesota, we deployed semipermeable membrane devices (SPMDs) in an impacted and a reference site to accumulate lipophilic contaminants. We then exposed native tadpoles (northern leopard frogs; Rana pipiens) to the SPMD extracts combined with two agricultural pesticides (atrazine, carbaryl) at two levels of UV radiation. RESULTS AND DISCUSSION: UV radiation alone caused a slight increase in hatching success and tadpole growth rate. Deformity rate among hatchlings was high following exposure to SPMD extracts from the reference site in the absence of UV, suggesting that chemicals present at this site are broken down by UV to less harmful forms, or become less bioavailable. Conversely, impacted site SPMD extracts caused hatchling deformities only in the presence of UV, suggesting that UV potentiates the teratogenicity of the compounds present there. Impacted site SPMD extracts significantly increased the number of bony triangles among metamorphs, a common deformity observed at this site. The incidence of skin webbings increased significantly with SPMD extracts from both sites as well as with our pesticide control containing atrazine and carbaryl alone. CONCLUSIONS: Higher deformity rates among tadpoles reared in the presence of UV radiation and SPMD extracts from sites where deformities are common indicates a chemical compound (or compounds) in the water at this site may be causing the deformities. RECOMMENDATIONS AND OUTLOOK: It is important to examine the effects of chemical stressors in the presence of other natural stressors (e.g., UV radiation) to gain a better understanding of how multiple stressors work to impact amphibians and amphibian populations.     

In utero therapy for fetal thoracic abnormalities

Fetal thoracic lung anomalies are rare. The specific diagnosis can be made by utilizing ultrasound, magnetic resonance imaging (MRI), and Doppler studies. Perinatal surveillance is required for large lesions and mediastinal shift regardless of the pathological diagnosis. These can cause physiological changes in the cardiovascular system with resulting hydrops. In utero therapies are variable but with no large randomized trials to compare risks and benefits. In most cases of fetal lung lesions, continued observation with postnatal therapy is the outcome. When fetal hydrops is present or impending, in utero fetal therapy is required to try to reverse that pathological course associated with fetal or neonatal death. Maternal morbidity is increased with the development of MIRROR syndrome following the presence of long-standing fetal hydrops and possible surgical procedures. Copyright © 2008 John Wiley & Sons, Ltd.     

Phenanthrene exposure produces cardiac defects during embryo development of zebrafish (Danio rerio) through activation of MMP-9

Phenanthrene (Phe) is one of the most abundant polycyclic aromatic hydrocarbons in the aquatic environment as a result of human activities. It is widely accepted that Phe has cardiotoxic effects. Even so, knowledge concerning the mechanism(s) of cardiac development toxicity is still limited. In this study, we exposed zebrafish embryos to environmentally relevant concentrations of Phe and then investigated its cardiotoxic effects and the mechanism(s) involved. Some cardiac morphogenetic defects, which was characterized by an abnormally looped and enlarged heart, dilated and thinner ventricular wall, and increased interstitial fibrosis, were observed in the Phe treated groups. The mRNA and protein expression levels of matrix metalloproteinase-9 (MMP-9), as well as the MMP-9 activity, were induced. Moreover, during co-treatment of the zebrafish embryos with MMP-9 inhibitor, the cardiac defects caused by Phe were attenuated. In addition, Phe exposure led to an up-regulation of transforming growth factor β (TGF-β), which plays a crucial role in mediating cardiac fibrosis. Taken together, our data indicated that the exposure to Phe of zebrafish embryos disrupted normal cardiac development, and that the cardiac defects induced by Phe were mediated by the MMP-9, while TGF-β was also involved in these cardiac defects.     

Abnormalities of the foetal cerebral cortex

Prenatal ultrasound has concentrated on readily visible cerebral structures including head size, shape, ventricles, CSP (cavum septi pellucidi), cerebellar size/vermian presence and cisterna magna. However, apart from these easily visible structures it is important to evaluate the brain itself. Patients who initially appear to have mild isolated findings such as borderline ventriculomegaly in fact can have many more subtle findings that significantly alter prognosis and management that can be detected on detailed examination of the brain. There has been rapid evolution in imaging these foetuses, especially with neurosonography and MRI, and a revolution in understanding the underlying genetic and biochemical mechanisms. There is increasing emphasis to detect cortical abnormalities as early as possible. This article reviews development of the cerebral cortex, the classification, aetiologies and clinical manifestations of cortical disorders, normal and abnormal appearances at ultrasound and MRI, and approaches to investigation. Copyright © 2009 John Wiley & Sons, Ltd.     

Role of prenatal detection of cardiac tumours in the diagnosis of tuberous sclerosis—report of two cases

Tuberous sclerosis is an autosomal dominant disease with variable expression. Little is known about the intrauterine course of the disease and the fetal age at which specific abnormalities may be detected. The role of prenatal detection of cardiac tumours in the diagnosis of two fetuses at 28 and 32 weeks' gestation based on fetal echocardiography is discussed. The prenatal and postnatal course of the disease is described.