Nuclear tools for characterising radiological dispersion in complex terrain: evaluation of regulatory and emergency response models

Routine operations of a nuclear research reactor and its facilities offer opportunities for collection of rare environmental tracer datasets which can be used for atmospheric dispersion model evaluation studies. The HIFAR reactor near Sydney, Australia, routinely emits the radioactive noble gas Ar-41, and other radionuclides such as Xe-133 and Xe-135 are also emitted from nearby radiopharmaceutical production facilities. Despite extremely low emission levels of these gases, they are nevertheless detectable using state-of-the-art technology, and sensitive detectors have been placed at four locations in the surrounding region which features complex terrain. The high research potential of this unique dataset is illustrated in the current study, in which predictions from two atmospheric dispersion models used for emergency response are compared with Ar-41 peak observations from the detector network under a range of stability conditions, and long-term integrated data is also compared with a routine impact assessment model. © 2005, Inderscience Enterprises Ltd

Association of <i>Toll-like receptor 4 (TLR4</i>) with chronic plaque type psoriasis and psoriatic arthritis

Family studies have provided overwhelming evidence for an underlying genetic component to psoriasis. Toll-like receptors (TLRs) are key transmembrane proteins in both the innate and adaptive immune responses which are known to be integral processes in psoriasis. Recent functional studies support this notion having suggested a role for TLR4 in the pathogenesis of psoriasis. Furthermore a missense polymorphism in the TLR4 gene has been associated with a number of autoimmune conditions, including Crohn diseases, making TLR4 a viable candidate gene for investigation. The aim of this study was to investigate polymorphisms across the TLR4 region with a high-density single nucleotide polymorphism (SNP) panel in a large cohort of patients with chronic plaque type psoriasis. Twenty SNPs were successfully genotyped using Sequenom iPLEX Gold platform in 2826 UK chronic plaque type psoriasis patients including subgroup data on presence of confirmed psoriatic arthritis (n = 1839) and early-onset psoriasis (n = 1466) was available. Allele frequencies for psoriasis patients were compared against imputed Wellcome Trust Case Control Consortium controls (n = 4861). Significant association was observed between a missense variant rs4986790 of TLR4 (Asp229Gly) and plaque type psoriasis (p = 2 × 10(-4)) which was also notable in those with psoriatic arthritis (p = 2 × 10(-4)) and early-onset psoriasis (p = 8 × 10(-4)). We present data suggestive of an association between a functional variant and an intronic variant of TLR4 and chronic plaque type psoriasis and psoriatic arthritis. However, validation of this association in independent cohorts will be necessary.</p

The Alberta Ambassador Program: delivering Health Technology Assessment results to rural practitioners

BACKGROUND: The purpose of Health Technology Assessment (HTA) is to make the best possible summary of the evidence regarding specific health interventions in order to influence health care and policy decisions. The need for decision makers to find relevant HTA data when it is needed is a barrier to its usefulness. These barriers are highest in rural areas and amongst isolated practitioners. METHODS: A multidisciplinary team developed an interactive case-based instructional strategy on the topic of chronic non-cancer pain (CNCP) management using clinical evidence derived by HTA. The evidence for each of 18 CNCP interventions was distilled into single-sheet summaries. Clinicians and HTA specialists ('Ambassadors') conducted 11 two-hour interactive sessions on CNCP in eight of Alberta's nine health regions. Pre- and post-session evaluations were conducted. RESULTS: The sessions were attended by 130 individuals representing 14 health and administrative disciplines. The ambassador model was well received. The use of content experts as ambassadors was highly rated. The educational strategy was judged to be effective. Awareness of the best evidence in CNCP management was increased. Although some participants reported practice changes as a result of the workshops, the program was not designed to measure changes in patient outcome. CONCLUSION: The ambassador program was successful in increasing awareness of the best evidence in CNCP management, and positively influenced treatment decisions. Its teaching methods were felt to be unique and innovative by participants. Its methods could be applied to other clinical content areas in order to increase the uptake of the results of HTA

Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

Unsynchronized cells of an essentially diploid strain of female Chinese hamster cells derived from lung tissue (CHL) were laser-UV-microirradiated (=257 nm) in the nucleus either at its central part or at its periphery. After 7–9 h postincubation with 0.5 mM caffeine, chromosome preparations were made in situ. Twenty-one and 29 metaphase spreads, respectively, with partial chromosome shattering (PCS) obtained after micro-irradiation at these two nuclear sites, were Q-banded and analyzed in detail. A positive correlation was observed between the frequency of damage of chromosomes and both their DNA content and length at metaphase. No significant difference was observed between the frequencies of damage obtained for individual chromosomes at either site of microirradiation. The frequency of joint damage of homologous chromosomes was low as compared to nonhomologous ones. Considerable variation was noted in different cells in the combinations of jointly shattered chromosomes. Evidence which justifies an interpretation of these data in terms of an interphase arrangement of chromosome territories is discussed. Our data strongly argue against somatic pairing as a regular event, and suggest a considerable variability of chromosome positions in different nuclei. However, present data do not exclude the possibility of certain non-random chromosomal arrangements in CHL-nuclei. The interphase chromosome distribution revealed by these experiments is compared with centromere-centromere, centromere-center and angle analyses of metaphase spreads and the relationship between interphase and metaphase arrangements of chromosomes is discussed

Neonatal retroauricular cellulitis as an indicator of group B streptococcal bacteremia: a case report

<p>Abstract</p> <p>Introduction</p> <p>The relation between cellulitis and Group B streptococcus infection in newborns and small infants was first reported during the early 1980s and named cellulitis-adenitis syndrome. We report a case of a neonate with cellulitis-adenitis syndrome in an unusual location (retroauricular).</p> <p>Case presentation</p> <p>A 21-day-old Caucasian female infant was brought to the emergency department with fever, irritability and a decreased appetite. Physical examination revealed erythema and painful, mild swelling in the right retroauricular region. The blood count and C-reactive protein level were normal. She was treated with ceftriaxone. The fever and irritability were resolved after 24 hours, and the cellulitis was clearly reduced after two days of hospitalization. Blood culture yielded Group B streptococcus.</p> <p>Conclusion</p> <p>A thorough evaluation must be done, and lumbar punctures for infants with cellulitis must be considered. We emphasize the lack of data about acute phase reactants to predict bacteremia and meningitis and to adjust the duration of parenteral antibiotic therapy to address this syndrome.</p

The scale of population structure in Arabidopsis thaliana

The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales

Chemical composition of Desulfovibrio desulfuricans lipid A

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica