Effect of hexachlorobenzene on the specific binding of 2,3,7,8,-TCDD to the hepatic receptor

The ability of HCB to interact with the receptor was investigated and . HCB, up to 1.0 μM, was not a potent competitor for the specific binding of [³H]-TCDD (0.3 nM) to rat hepatic cytosol. Administration of HCB (3000 ppm in the diet) to rats for up to 7 days resulted in a decrease in the specific binding of [³H]-TCDD to hepatic cytosol, as compared to pair-fed control rats. These results suggest that HCB may be able to interact, either directly or indirectly, with the hepatic receptor .     

Formation of volatile iodinated alkanes in soil: results from laboratory studies

Volatile iodinated organic compounds play an important role in the tropospheric photochemical system, but the current knowledge of the known sources and sinks of these alkyl iodides is still incomplete. This paper describes a new source of alkyl iodides from the pedosphere. Different organic-rich soils and humic acid were investigated for their release of volatile organoiodides. Six volatile organoiodides, iodomethane, iodoethane, 1-iodopropane, 2-iodopropane, 1-iodobutane and 2-iodobutane were identified and their release rates were determined. We assume an abiotic reaction mechanism induced by the oxidation of organic matter by iron(III). The influence of iron(III), iodide and pH on the formation of alkyl iodides was investigated. Additionally, different organic substances regarded as monomeric constituents of humus were examined for the production of alkyl iodides. Two possible reaction pathways for the chemical formation of alkyl iodides are discussed. As humic acids and iron(III) are widespread in the terrestrial environment, and the concentration of iodide in soil is strongly enriched (compared to seawater), this soil source of naturally occurring organoiodides is suggested to contribute significantly to the input of iodine into the troposphere.     

Indicators of Biodiversity and Conservational Wildlife Quality on Danish Organic Farms for Use in Farm Management: A Multidisciplinary Approach to Indicator Development and Testing

Organic farming is expected to contribute to conserving national biodiversity on farms, especially remnant, old, and undisturbed small biotopes, forests, and permanent grassland. This objective cannot rely on the legislation of organic farming solely, and to succeed, farmers need to understand the goals behind it. A set of indicators with the purpose of facilitating dialogues between expert and farmer on wildlife quality has been developed and tested on eight organic farms. “Weed cover in cereal fields,” was used as an indicator of floral and faunal biodiversity in the cultivated land, and “uncultivated biotope area” on the farm was used as a general measure of wildlife habitats. Functional grouping of herbaceous plants (discriminating between “high conservation value” plant species and “competitive”/“ruderal” species) and low mobility butterflies were used as indicators of conservation value, especially focusing on the few sites left with considerable remnant conservation value. The dialog processes revealed that the organic farmers’ ideas and goals of conservation of wildlife quality were not necessarily the same as for biologists; the farmers expressed very different opinions on the biological rooted idea, that wildlife quality is related to the absence of agricultural impact. However, farmers also stated that the information given by the indicators and especially the dialogue with the biologist had influenced their perception and awareness of wildlife. We conclude that, combined with a dialogue process, using these indicators when mapping wildlife quality could be an important key component of a farm wildlife management advisory tool at farm level.     

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.     

Genetic amniocentesis at 7–14 weeks of gestation

Genetic amniocentesis performed at 7–14 weeks of gestation was studied in a series of 138 patients of whom 50 wanted termination of pregnancy (⩽ 12 weeks). The material for analysis consisted of 132 samples due to two sampling failures and four samples being handled incorrectly. Forty-eight samples (36 per cent) were taken at 7–12 weeks of gestation, mainly transvaginally (36/48:75 per cent). The success rate of culture and karyotyping increased with the duration of pregnancy, but was only satisfactory from week 11 onwards. The time until harvest was then 14–15 days. The transvaginal approach is easy to perform and was accepted by the women, but we experienced bacterial or fungal overgrowth in 17 per cent of these samples, whereas no infection occurred in the samples taken transabdominally (n = 96). We conclude that genetic amniocentesis is feasible from week 11, but further studies concerning side effects, especially focusing on the procedure-related abortion risk, should be carried out before early amniocentesis is routinely applied.     

Chemotherapy of bacterial plasmids

Pharmacological approaches to plasmid chemotherapy are: 1) discovery of novel antibacterial drugs against which plasmids do not carry resistance genes, 2) molecular modification of existing drugs to render them non-susceptible to plasmid-encoded enzymes, 3) development of drugs which are selective inhibitors of plasmid DNA replication, 4) development of drugs which inhibit phenotypic expression of plasmid genes, and 5) development of drugs which are inhibitors of drug-inactivating enzymes that are plasmid gene products.