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.     

Split notochord syndrome variant: prenatal findings and neonatal management

Spilt notochord syndrome is an extremely rare form of spinal dysraphism characterized by a complete cleft of the spine and a persistent communication between endoderm and ectoderm. A variant of split notochord syndrome was diagnosed in a 25-week-old fetus showing a prolapsed congenital colostomy and a spinal cystic lesion. The final diagnosis included protruding colon segment, imperforate anus with a rectourethral fistula and lipomyelomeningocele. The ultrasound features of the condition and the post-natal management are discussed. The neonate was successfully treated with a posterior sagittal anorectoplasty, while the lipomyelomeningocele was resected at a later stage. Copyright © 2005 John Wiley & Sons, Ltd.     

Loss of genetic diversity in Harpacticoida near offshore platforms

Offshore oil and gas production platforms can be a source of chronic stress that could lead to sublethal impacts on resident benthic organisms. In June 1993 and January 1994, genetic diversity of Harpacticoida (Copepoda) living proximal to operating, offshore platforms in the Gulf of Mexico was estimated to test if platforms are associated with strong selective pressures. Because harpacticoids have short generation times and direct benthic development, they are suitable organisms for examining population responses. Genetic diversity was estimated by comparing restriction fragment length polymorphisms generated from mitochondrial DNA amplified by the polymerase chain reaction on individuals of five species (Cletodes sp., Enhydrosoma pericoense, Normanella sp., Robertsonia sp., and Tachidiella sp.). Populations living at Near regions (stations<50 m from a platform) had significantly less haplotype diversity than populations of the same species living at Far regions (stations>3 km from a platform). The levels of haplotype diversity exhibited by the Far populations were similar at three different platforms located hundreds of kilometers apart. The differences in haplotype diversity between Near and Far regions were the result of a higher proportion of dominant haplotypes, and a loss of less common haplotypes. Haplotypic diversity was inversely correlated with a multivariate measurement of levels of sediment contaminants. The pattern of haplotype diversity on the Gulf of Mexico continental shelf seems to consist of a uniform level of haplotype diversity, punctuated by islands of lower diversity around oil and gas platforms. The selective pressures that lead to a loss of genetic diversity may be the result of contaminants, other differences in the physico-chemical environment, or disturbance in general.     

Oxygen and carbon isotopic composition of fish otoliths

Oxygen and carbon isotopic composition of the aragonite of fish otoliths was measured on 175 specimens comprising 24 different species in 1989 and 1990. All specimens but two came from the northern Adriatic Sea or the northern Tyrrhenian Sea (two freshwater specimens were studied for comparison with the marine fish). The data obtained confirm the results of previous research suggesting the existence of equilibrium conditions between the otolith aragonite and ambient water with respect to ·¹⁸O(CO₃ ^2-) values. Examination of one of the species indicated that the CaCO₃ of otoliths probably accumulates continuously over time, seasonal isotopic changes being clearly visible (from a set of radial spot samples) for both oxygen and carbon isotopes. The apparent isotopic equilibrium with ambient water suggests that the ¹⁸O(H₂O) of the endolymph is equal to that of seawater and considerably different from that of fish body water. In the case of ¹³C(CO₃ ^2-), isotopic equilibrium with dissolved carbon species in seawater is never reached, even though the contribution of metabolic CO₂ is variable among different species and even among different individuals of the same species. This rules out the possibility of using ¹³C(CO₃ ^2-) values obtained from fossil otoliths for paleoenvironmental and paleobiological conclusions.     

Lipid content of some Caribbean corals in relation to depth and light

Three procedures for the extraction of coral lipids were compared and a rapid and effective method for future use is suggested. This method was used to measure the lipid content of the branching coral Porites porites (Pallas) and the massive corals Montastrea annularis (Ellis and Solander) and Siderastrea siderea (Ellis and Solander) during July and August 1991. P. porites and M. annularis were sampled on two fringing reefs, each characterised by different water quality affecting light transmission, and at depths of down to 30 m on a barrier reef on the west coast of the island. m. annularis contained, on average, 29% of dry weight as lipid, and there were no significant differences in lipid levels between corals sampled on either fringing reef at 3 and 6 m, or between fringing reefs and the barrier reef at 13, 20 or 30 m depth. Five samples were also taken from a single massive colony of S. siderea at 3 m on a fringing reef and at 13, 20 and 30 m depth on the barrier reef. Values for lipid ranged from 26 to 35% of dry tissue weight. P. porites from 3 and 6 m depth on both fringing reefs contained the same amount of lipid (11% of dry tissue weight). However, at 13 m depth on the barrier reef this coral contained significantly less lipid (8.5% of dry tissue weight). This difference may be attributable to a higher nutritional intake by P. porites on the fringing reefs.     

Laboratory observations on spawning,fecundity and early development of a mesopelagic ostracod,Conchoecia pseudodiscophora,from the Japan Sea

The fate of the polycyclic aromatic hydrocarbon [³H]benzo[a]pyrene (BaP) was examined in two species of scleractinian corals, Favia fragum (Esper) and Montastrea annularis (Ellis and Solander), which were collected in the patch reefs surrounding Alina's Reef (25°23.25N; 80°09.8W) in Biscayne National Park, Florida, USA, in July, 1990. Corals were exposed to initial concentrations of 5 g/l in a simple static system for 25 h. BaP uptake was estimated from the disappearance of BaP from the water. Uptake rates were 6.5±0.7 and 10.8±0.2 g BaP cm^-2h^-1 for F. fragum and M. annularis, respectively, at initial BaP concentrations and were directly proportional to the concentration of BaP in the water. The separation of zooxanthellae from coral tissue revealed that zooxanthellae can accumulate up to 53 and 64% of the total BaP-derived radioactivity present in F. fragum and M. annularis, respectively. Both corals metabolized BaP slowly, as most of the accumulated radioactivity was present as the unmetabolized chemical. However, aqueous and organic-soluble metabolites were found in both the animal and zooxanthellae fractions. Analysis by high-performance liquid chromatography (HPLC) revealed that both species of corals metabolized BaP to various tetrols, triols, dihydrodiols, quinones and phenols, although the pattern of metabolites differed between species. Zooxanthellae contained some of the same Phase I metabolites found in the animal tissue; however, tetrols and triols were absent in extracts from the zooxanthellae. The elimination of BAP from corals was also slow; approximately 38 and 65% of the accumulated radioactivity was still present in F. fragum and M. annularis, respectively, 144 h following the transfer of exposed corals to an uncontaminated flow-through seawater system.