Inductive potency of TCDD, TBDD and three 2,3,7,8-mixed-halogenated dioxins in liver microsomes of male rats. Enzyme kinetic considerations

The enzyme inducing potency of single doses of three 2,3,7,8-substituted mixed halogenated dibenzo-p-dioxins was investigated and compared with 2,3,7,8-TCDD and 2,3,7,8-TBDD. All substances showed a quite similar potency for EROD induction. The use of a substrate concentration of 0.5 μM ethoxyresorufin is strongly recommended.     

Sources and fate of nitrosodimethylamine and its precursors in municipal wastewater treatment plants.

To assess the occurrence and fate of nitrosodimethylamine (NDMA) and its precursors in wastewater treatment plants, samples from wastewater treatment plants and industrial sources were analyzed for NDMA, total NDMA precursors, and dimethylamine (DMA). The median concentration of NDMA in untreated wastewater was approximately 80 ng/L, with maximum concentrations up to 790 ng/L presumably occuring because of sources unrelated to domestic wastewater. Concentrations of DMA in untreated wastewater ranged from approximately 50 to 120 microg/L and accounted for a majority of the NDMA precursors. The removal of NDMA during secondary biological treatment exhibited considerable variability, with overall removal ranging from 0 to 75%. In contrast, removal of NDMA precursors and DMA generally exceeded 70%. The median concentration of NDMA in secondary effluent before disinfection was 46 ng/L. Although DMA was removed during secondary treatment, other NDMA precursors in wastewater effluent will result in formation of additional NDMA upon disinfection with chloramines.     

Fetal presentation of morquio disease type A

A fetus with mucopolysaccharidosis type IV A (Morquio type A) is described. The family had one affected child exhibiting symptoms of classical Morquio A disease, and late in the subsequent pregnancy prenatal diagnosis was requested. At 23 weeks' gestation, moderate ascites was detected by detailed ultrasound scan and keratan sulphate was found in the amniotic fluid. The pregnancy was terminated by prostaglandin induction and the diagnosis of mucopolysaccharidosis type IV A was confirmed by demonstration of a deficiency of N-acetylgalactosamine-6-sulphate (GalNac-6-S) sulphatase in cultured amniotic cells and in post-mortem fibroblast cultures. The activities of β-galactosidase and arylsulphatase A were normal, ruling out Morquio disease type B and multiple sulphatase deficiency. These results indicate that mucopolysaccharidosis IV A (a disease that predominantly affects the skeletal system) may produce ascites in the fetus to such an extent that it can be detected by ultrasound.     

Lichtallergien und andere Lichtempfindlichkeitsreaktionen

Adverse reactions of the skin to light comprise a number of different dermatologic conditions. In light-‘allergies’ in the narrower sense non-ionised electromagnetic radiation (ultraviolet (UV)-A/-B radiation or visible light) provokes an immunologic or allergic skin reaction. These include solar urticaria, an, immunoglobulin E-mediated, immediate-type allergic photoreaction, photoallergic contact dermatitis and photoallergic (drug) exanthema, which are cell-mediated, delayed-type allergic photoreactions due to photosensitization, chronic actinic dermatitis and polymorphic light eruption. Beyond it there are nonimmunologic photosensitive and photoaggravated skin diseases, like exogenous and endogenous phototoxicity, xeroderma pigmentosum, which is based on a genetic defect, or the autoimmune disease lupus erythematosus.     

The bottlenose dolphin community of Doubtful Sound features a large proportion of long-lasting associations

More than 12 studies of different bottlenose dolphin populations, spanning from tropical to cold temperate waters, have shown that the species typically lives in societies in which relationships among individuals are predominantly fluid. In all cases dolphins lived in small groups characterised by fluid and dynamic interactions and some degree of dispersal from the natal group by both sexes. We describe a small, closed population of bottlenose dolphins living at the southern extreme of the species' range. Individuals live in large, mixed-sex groups in which no permanent emigration/immigration has been observed over the past 7 years. All members within the community are relatively closely associated (average half-weight index>0.4). Both male–male and female–female networks of preferred associates are present, as are long-lasting associations across sexes. The community structure is temporally stable, compared to other bottlenose dolphin populations, and constant companionship seems to be prevalent in the temporal association pattern. Such high degrees of stability are unprecedented in studies of bottlenose dolphins and may be related to the ecological constraints of Doubtful Sound. Fjords are low-productivity systems in which survival may easily require a greater level of co-operation, and hence group stability. These conditions are also present in other cetacean populations forming stable groups. We therefore hypothesise that ecological constraints are important factors shaping social interactions within cetacean societies.Communicated by D. Watts