The effect of certain intrinsic and extrinsic variables on the acute toxicity of selected organophosphorus insecticides to the mummichog, Fundulus heteroclitus.

The acute toxicity of two organophosphorus (OP) insecticides, azinphosmethyl and acephate, was evaluated in the mummichog, Fundulus heteroclitus. In addition, the effects of certain intrinsic (sex) and extrinsic (salinity and multiple toxicant interraction) variables on the toxic response were also investigated. Azinphosmethyl was by far the most toxic of the two OP insecticides with a 96h LC50 approximately 100,000 x lower than that for acephate. Slight sex differences were observed in the sensitivity of mummichogs to each of the OP insecticides with male fish being marginally more sensitive. Significant effects of low salinity stress were observed only with acephate exposure and, in this case, low salinity appeared to be slightly protective. In general, all of the insecticide mixtures (azinphosmethyl/endosulfan, azinphosmethyl/fenvalerate and acephate/fenvalerate) tested exhibited simple additive toxicity.     

The Ratio of Rubidium to Caesium in Threespine Stickleback (Gasterosteus Aculeatus), Benthic and Limnetic Sticklebacks (Gasterosteus), and Juvenile Sockeye Salmon (Oncorhynchus Nerka)

The ratios of rubidium to caesium were investigated in juvenile sockeye salmon (Oncorhynchus nerka), threespine stickleback (Gasterosteus aculeatus) and benthic and limnetic sticklebacks (Gasterosteus) as a means of separating zooplankton consumers from benthic prey consumers. Only benthic and limnetic sticklebacks had Rb to Cs ratios that were influenced by diet. Ratios were higher in limnetic stickleback whose diet consists mainly of zooplankton compared with benthic stickleback which consume benthic prey. Ratios in juvenile sockeye appeared to be influenced by the concentrations of rubidium and caesium in the egg yolk during the early period of growth. in three-spine stickleback that inhabited both the littoral and limnetic zone of the same lake, results suggested that fish must occupy each area for several months before rubidium to caesium ratios in tissues reflect concentrations in prey.     

Prenatal diagnosis in three cases of iniencephaly with unusual postmortem findings

Iniencephaly is a rare and lethal congenital malformation of the neural tube characterized by occipital bone defect, cervical dysraphism, fixed retroflexion of the fetal head and severe lordosis of the cervicothoracic spine. The etiology is unknown. Prenatally diagnosed cases of iniencephaly are rare because careful and early ultrasonographic evaluation is necessary. We present three cases of iniencephaly prenatally diagnosed by sonography at 20–22 weeks' gestation in which therapeutic abortion was induced. The sonographic findings were compatible with the postmortem findings. The present cases of iniencephaly were found to carry unusual associated malformations such as two lobes in the right lung and chorangiosis of the placenta. Only hypoplastic lungs have been reported by previous authors. We also studied the 677C→T mutation on the methylenetetrahydrofolate reductase gene in the parents in one of the present cases. The mother was found to be heterozygous for the 677CT polymorphism. Copyright © 2001 John Wiley & Sons, Ltd.     

The role of colonization in determining spatial patterns of Proscoloplos bondi sp. nov. (Orbiniidae: Annelida) in coralline algal turf

We describe Proscoloplos bondi sp. nov., a new species of orbinid polychaete found in coralline algal turf on rocky intertidal shores near Sydney, Australia. We used field sampling to describe P. bondi's patterns of spatial and temporal variation on a number of shores. P. bondi was significantly more abundant in low- than in mid-shore areas (ANOVA, P<0.05), but local populations were extremely variable in space and time. Despite extensive sampling, we did not find evidence of sexual reproduction in P. bondi, but commonly observed worms with regenerating heads and tails, which indicated the importance of asexual reproduction. We, therefore, tested the hypothesis that adult colonization contributes to its patterns of abundance. First, patches of artificial turf were placed near to and away from natural coralline turf and sampled after 2, 4 and 12 months. Generally, populations established themselves more quickly in patches of new habitat directly adjacent to coralline turf than in patches that were isolated. Second, patches of turf were deployed for 2-week periods in low- and mid-shore areas (repeated four times). Proscoloplos bondi were found significantly more often in patches in low-shore areas than in mid-shore areas and at some sites more than others (ANOVA, P<0.05), demonstrating the importance of adult colonization in determining patterns of abundance. Overall, the limited dispersal from spatially and temporally ephemeral populations of P. bondi combined with the patchiness of coralline turfs suggest that metapopulation dynamics may be important in the persistence of P. bondi on rocky shores.Communicated by G.F. Humphrey, Sydney     

Cryptic 1p36.3/6q25.2 translocation in three generations ascertained through a foetus with IUGR and cerebral malformations

Here we describe a foetus with intrauterine growth retardation (IUGR), cerebral malformations and a 46,XY,der(1),t(1;6)(p36.3;q25.2) karyotype owing to a familial cryptic translocation segregating in three generations. A balanced translocation was present in the mother, the maternal uncle, the aunt and the grandmother. A female first cousin with dysmorphisms, hydrocephalus and mental retardation was a carrier of a partial trisomy 1p and a partial monosomy 6q. Multiple miscarriages were present in the family pedigree. Parents of the foetus had three other pregnancies: a male with a balanced translocation, and two foetuses with 1p36.3–pter monosomy and 6q25.2–qter trisomy. Copyright © 2003 John Wiley & Sons, Ltd.     

Dilated coronary sinus in prenatal echocardiography; identification,associations and outcome

The dilated coronary sinus (DCS) has only recently been clearly visualised in the fetus due to progress in prenatal echography. This is a retrospective study of 22 fetuses presenting with DCS revealed by prenatal echography. We report the circumstances leading to the detection of a DCS and the neonatal outcome of these fetuses. The coronary sinus was defined as dilated depending on its visualisation in cross-section from the ‘4 chamber’ view, as well as a pseudo inter-atrial septal defect from a more posterior view. In each case the gestational age, circumstances of detection, associated anomalies and postnatal outcome are reported. The circumstances were: evaluation of a clearly identified DCS in four cases and during detailed fetal echocardiography because of suspected congenital heart disease in 18 cases. Five cases were associated with a cardiac anomaly, three with an extracardiac anomaly, six with both cardiac and extracardiac anomaly and eight were isolated. Postnatal outcome was related to the associated anomaly. In conclusion, it is important that the echography image be correctly interpreted, as a DCS often implies possible associated defects and therefore affects prognosis. When not associated with other anomalies this condition is not considered serious. Copyright © 2002 John Wiley & Sons, Ltd.     

Fetal phenotype of Prader–Willi syndrome due to maternal disomy for chromosome 15

Prader–Willi syndrome (PWS) results from either paternal deletion of 15q11–q13, or maternal uniparental disomy (UPD) of chromosome 15 or imprinting center mutation. Prenatal diagnosis of PWS is currently indicated for chromosomal parental translocation involving chromosome 15 and for decreased fetal movements during the third trimester of gestation. Here we present the prenatal diagnosis of PWS during the first trimester of gestation and autopsy findings. Chorionic villus sampling (CVS) was performed for advanced maternal age at 13 weeks' gestation. CVS showed mosaicism including cells with a normal karyotype and cells with trisomy 15. Amniocentesis showed cells with a normal karyotype. Molecular analysis demonstrated that the fetus had a typical PWS abnormal methylation profile and maternal disomy for chromosome 15. Fetal ultrasound examination showed slightly enlarged lateral ventricles and hypoplasic male external genitalia without intra-uterine growth retardation. The autopsy showed a eutrophic male fetus with facial dysmorphy, hypoplasic genitalia, abnormal position of both feet and posterior hypoplasia of the corpus callosum. This report points out that in a karyotypically normal fetus with ambiguous male external genitalia and cerebral anomalies, extensive cytogenetic and molecular biology studies are strongly recommended because of risk of PWS. Copyright © 2003 John Wiley & Sons, Ltd.