Evaluation of Cs, Xe and H activity concentrations monitored in the Arctic atmosphere.

This paper provides a brief introduction to the Arctic atmospheric radioactivity monitoring network. A decade of monitoring results have shown the Cs background levels in Arctic air range from 0.05 to 1.

The dispersion of 99Tc in the Nordic Seas and the Arctic Ocean: a comparison of model results and observations.

The radionuclide (99)Tc had been discharged from the nuclear reprocessing facility in Sellafield (UK) into the Irish Sea in increased amounts in the 1990s. We compare the simulated dispersion of (99)Tc in surface water as calculated by a hydrodynamic model and an assessment box model with field-observations from 1996 to 1999 to study concentrations, pathways and travel times. The model results are consistent with the observations and show the typical pathway of dissolved radionuclides from the Irish Sea via the North Sea along the Norwegian Coast.

Plutonium isotope ratios in the Yenisey and Ob estuaries.

Over the past 50 years, nuclear weapons' tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems.

A 'weighted' 137Cs inventory calculation of Reservoir 11, Mayak P.A., Russia with the novel use of remotely sensed information and sample data in a GIS.

The objective of this study was to make a robust 137Cs inventory calculation for Reservoir 11 in the Mayak Production Associations industrial cascade of reservoirs. High resolution satellite photographs provided information about the original Techa River and floodplain environment before, during and also after Reservoir 11 was constructed. The images provided important clues about the old Techa River system and also showed the extent of the contaminated area.

The accidental sinking of the nuclear submarine, the Kursk: monitoring of radioactivity and the preliminary assessment of the potential impact of radioactive releases.

Measurements of samples taken from the close vicinity of the Kursk during two expeditions to the site in August and October 2000, indicate that no leakage of radionuclides from the reactors has been observed. Only background levels in the range 0.0-0.

Radioactive contamination in the marine environment adjacent to the outfall of the radioactive waste treatment plant at ATOMFLOT, northern Russia.

RTP "ATOMFLOT" is a civilian nuclear icebreaker base located on the Kola Bay of northwest Russia. The objectives of this study were to determine the distributions of man-made radionuclides in the marine environment adjacent to the base, to explain the form of the distributions in sediments and to derive information concerning the fate of radionuclides discharged from ATOMFLOT. Mean activity concentrations (d.

Expression of a mutated form of the p85alpha regulatory subunit of phosphatidylinositol 3-kinase in a Hodgkin's lymphoma-derived cell line (CO).

Phosphatidylinositol (PI) 3-kinase plays an important role in a variety of biological processes, including proliferation and apoptosis. PI3-kinase is a heterodimer consisting of an 85 kDa adapter protein (p85) containing one SH3 domain and two SH2 domains and a 110 kDa catalytic subunit (p110). Recently an oncogenic form of p85 named p65-PI3K lacking the C-terminal SH2 domain has been cloned from an irradiation-induced murine thymic lymphoma and transgenic mice expressing p65-PI3K in T lymphocytes develop a lymphoproliferative disorder.

Radioactive contamination in the Arctic--sources, dose assessment and potential risks.

Arctic residents, whose diets comprise a large proportion of traditional terrestrial and freshwater foodstuffs, have received the highest radiation exposures to artificial radionuclides in the Arctic. Doses to members of both the average population and selected indigenous population groups in the Arctic depend on the rates of consumption of locally-derived terrestrial and freshwater foodstuffs, including reindeer/caribou meat, freshwater fish, goat cheese, berries, mushrooms and lamb. The vulnerability of arctic populations, especially indigenous peoples, to radiocaesium deposition is much greater than for temperate populations due to the importance of terrestrial, semi-natural exposure pathways where there is high radiocaesium transfer and a long ecological half-life for this radionuclide.

Antisense oligodeoxynucleotides as a tool in developmental neuroendocrinology.

Antisense oligodeoxynucleotides have been highly successful agents at modulating gene expression in the adult brain and widely exploited in the field of neuroendocrinology. We have also used this technique in the developing brain to explore the role of select proteins during sensitive periods of development, particularly those influenced by steroid hormones. Presented here are the technical details of using antisense oligodeoxynucleotides in the neonatal brain, as well as a review of some of our successes and failures.

Calbindin-D28k immunoreactivity is a marker for a subdivision of the sexually dimorphic nucleus of the preoptic area of the rat: developmental profile and gonadal steroid modulation.

Calbindin-D28k (calbindin) is a 28 kilodalton calcium binding protein which potentially plays a role in neuroprotection. We report here the normal development and gonadal steroid modulation of a sexually dimorphic group of calbindin immunoreactive cells within the sexually dimorphic nucleus of the preoptic area (SDN) which we call the calbindin-immunoreactive SDN or CALB-SDN. Beginning on PN2, a faintly immunoreactive CALB-SDN is present, however, the volume is not sexually dimorphic.

Developmental sex differences in calbindin-D(28K) and calretinin immunoreactivity in the neonatal rat hypothalamus.

The proteins calbindin-D(28K) and calretinin buffer intracellular calcium and are speculated to be involved in the integration of neuronal signaling. Using Western blot analysis, we compared the levels of calbindin-D(28K) and calretinin in the developing male and female rat hypothalamus on postnatal days (PN) 0, PN2, PN4, PN6, PN8, and PN10. Analysis of variance (ANOVA) of mean calbindin levels indicated a significant effect of sex (p View Article and Find Full Text PDF

Radioactive contamination from dumped nuclear waste in the Kara Sea--results from the joint Russian-Norwegian expeditions in 1992-1994.

Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 137Cs, 60Co, 90Sr and 239,240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place.

Spatial variation in the vulnerability of Norwegian Arctic counties to radiocaesium deposition.

Under the Arctic Monitoring and Assessment Programme (AMAP), studies have been undertaken to compare potential fluxes of radiocaesium via important food products. The results for three Norwegian Arctic counties are presented in this paper. The comparative importance of different foodstuffs in contributing to collective dose varies spatially due to differing rates of production and transfer.

Osteoblasts and chondrocytes are important target cells for the toxic effects of lead.

The skeleton is a major repository for divalent cations, including toxic heavy metals such as lead. Unfortunately the effects of such agents on bone (and cartilage) have been minimally investigated in the past. With the current level of understanding of the mechanisms of bone formation and cartilage development it is now appropriate to begin to research the effects of lead on cellular processes.

Fate of human chorionic gonadotropin bound to rat corpora lutea.

The current studies were designed to ascertain the fate of hCG bound to rat corpora luteal cell receptors. Graded doses of highly purified hCG (CR119), ranging from 0.1-10.

Characterization of a small molecular size urinary immunoreactive human chorionic gonadotropin (hCG)-like substance produced by normal placenta and by hCG-secreting neoplasms.

Urine obtained from normal pregnant women as well as from patients with hCG-secreting tumors frequently contains native hCG and free hCG subunits when separated on Sephadex G-100. In addition, a small amount of an immunoreactive, hCG-like, low molecular weight substance is usually observed in those chromatograms and represents less than 1% of the total immunoreactive hCG present. Two patients with widely metastatic hCG-secreting tumors excreted disproportionately large quantities of that low molecular weight substance, and that observation raised the possibility that this substance was a secretory and not a degradative product of the hCG molecule.