240 research outputs found
Forest-Tundra Neighbouring the North Pole: Plant and Insect Remains from the Plio-Pleistocene Kap København Formation, North Greenland
The Kap Kobenhavn Formation in northeast Peary Land, Greenland, is believed to be 2.0-2.5 million years old, i.e., from the Plio-Pleistocene transition. The dating is primarily based on biostratigraphical correlation of lower marine fauna and a few fragments of terrestrial mammals. Although deposited in marine and coastal environments, the sediments contain abundant remains of terrestrial and limnic organisms. This paper examines macroscopic plant and insect remains. About 60 taxa of vascular plants and 120 insect taxa have so far been identified. Nearly all of the named insect species are extant, extralimital forms, generally of a recent subarctic/boreal and more or less circumpolar distribution. The species composition shows that upland areas were covered with forest-tundra and heathland and that mesotrophic, well-vegetated lakes and a number of other wetland localties existed in the area. The presence of arctic plants in the formation puts some time constraints on their origin.
A quantitative approach to the sexual reproductive biology and population structure in some arctic flowering plants: Dryas integrifolia, Silene acaulis and Ranunculus nivalis
The population ecology of three species in northwest Greenland (Dryas integrifolia, Silene acaulis and Ranunculus nivalis) was studied in two consecutive seasons. Flowering phenology, population structure, flowering biology (including numbers of pollen grains per anther, germinated pollen grains per stigma, ovules per gynoecium, seeds per fruit), pollination and insect activity were the main features investigated.
They were related to the micro- and macroclimatic conditions.
The results can be summarized as follows:
The unpredictability of the quality and length of the growing season makes the success of the reproductive cycle (i.e. production of mature seeds) very uncertain.
There are seedlings at the studied sites of the three species.
Most of the seedlings disappear.
Population structure results indicate that seedlings become established in at least some years, but input of new individuals is episodic.
Of the three species studied, R. nivalis allocates most resources to reproduction.
Percentage normal pollen varies mostly between plants, less between days and sites (D. integrifolia).
All three species are self-compatible.
Full seed set is obtained only after insect visits.
In S. acaulis seed set may be limited by the number of pollen grains reaching the stigmas.
The flowers provide food (pollen and nectar) for the insects. They also provide shelter, warmth, and a mating place for them.
There are sufficient insect visits per flower to ensure seed set, except possibly in S. acaulis.
About 1 % of total pollen grain production is found as germinated pollen grains on stigmas.
The utilization of pollen and stigmas varies between the three species. R. nivalis is the most efficient, whereas D. integrifolia is the most extravagant.
A cold and rainy summer in 1976 resulted in conspicuously lower seed set in 1977 in spite of the latter summer being comparatively dry and warm.
A 'reproductive budget' quantifying the various steps in the reproductive cycle is presented
Thule Inuit environmental impacts on Kangeq, southwest Greenland
The Leverhulme Trust is thanked for financial support for the project “Footsteps on the Edge of Thule” (Programme Grant F/00 152/Q), directed by Kevin Edwards (University of Aberdeen), Andy Dugmore, Eva Panagiotakopulu (both University of Edinburgh), and Ian Simpson (Stirling University). We are grateful to Andy McMullen, Kirsty Collinge and Ian Simpson for assistance with fieldwork and advice. Gordon Cook is thanked for the provision of radiocarbon dates. Jamie Bowie kindly assisted with the production of diagrams relating to palynological work. The maps and section were drawn by Anastasios Panagiotakopoulos, whose help is warmly acknowledged. Last but not least we are grateful for the helpful comments by the editor and three anonymous reviewers.Peer reviewedPostprin
Preliminary archaeoentomological analyses of permafrost-preserved cultural layers from the pre-contact Yup’ik Eskimo site of Nunalleq, Alaska : implications, potential and methodological considerations
Acknowledgements Site excavation and samples collection were conducted by archaeologists from the University of Aberdeen, with the help of archaeologists and student excavators from the University of Aberdeen University of Alaska Fairbanks and Bryn Mawr College, Kuskokwim Campus, College of Rural Alaska and residents of Quinhagak and Mekoryuk. This study is funded through AHRC grant to the project ‘Understanding Cultural Resilience and Climate Change on the Bering Sea through Yup’ik Ecological Knowledge, Lifeways, Learning and Archaeology’ to Rick Knecht, Kate Britton and Charlotta Hillderal (University of Aberdeen; AH/K006029/1). Thanks are due to Qanirtuuq Inc. and Quinhagak, Alaska for sampling permissions and to entomologists working at the CNC in Ottawa for allowing access to reference collections of beetles, lice and fleas. Yves Bousquet, Ales Smetana and Anthony E. Davies are specially acknowledged for their help with the identification of coleopteran specimens. Finally, we would also like to thank Scott Elias for useful comments on the original manuscript.Peer reviewedPublisher PD
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Open-label extension of a phase 2 trial of risankizumab in patients with moderate-to-severe Crohn's disease
Background: Risankizumab, an anti-interleukin-23 antibody, was superior to placebo in achieving clinical and endoscopic remission at week 12 in a randomised, phase 2 induction study in patients with moderately to severely active Crohn’s disease. The efficacy and safety of extended intravenous induction and/or subcutaneous maintenance therapy with risankizumab was assessed.
Methods: Following 12-week, double-blind, randomised, induction treatment comparing 200 mg or 600 mg intravenous risankizumab to placebo every 4 weeks, patients without deep remission, defined as clinical (Crohn’s Disease Activity Index <150) and endoscopic remission (Crohn’s Disease Endoscopic Index of Severity [CDEIS] ≤4 [≤2 for patients with isolated ileitis]), received open-label 600 mg intravenous risankizumab (every 4 weeks) and patients in deep remission underwent washout until week 26 (Period 2). At week 26, patients in clinical remission received maintenance treatment (Period 3) with 180 mg subcutaneous risankizumab (every 8 weeks). Efficacy endpoints included clinical and endoscopic response and remission at weeks 26 (Period 2) and 52 (Period 3) respectively; safety was assessed through both periods. Study registration: ClinicalTrials.gov, NCT02031276.
Findings: In Period 2, 101 patients were treated with 600 mg risankizumab resulting in an increase in clinical remission rates at week 26 versus week 12 for all original designated treatment groups: 55% versus 18%, 59% versus 21%, and 47% versus 26% for placebo, 200, and 600 mg risankizumab, respectively. Of the 62 patients receiving maintenance treatment, 54 completed treatment. At week 52, clinical remission was maintained by 71% of patients; endoscopic remission and response (>50% CDEIS reduction from baseline) was achieved by 35% and 55% of patients, respectively, and 29% of patients achieved deep remission. Risankizumab was well tolerated with no new safety signals.
Interpretation: Extended induction treatment with open-label intravenous risankizumab was effective in increasing clinical response and remission rates at week 26. Open-label subcutaneous risankizumab maintained remission till week 52 in most patients who were in clinical remission at week 26. Selective blockade of interleukin-23 warrants further evaluation as treatment for Crohn’s disease.Boehringer Ingelhei
Fulminant Staphylococcus lugdunensis septicaemia following a pelvic varicella-zoster virus infection in an immune-deficient patient: a case report
<p>Abstract</p> <p>Introduction</p> <p>The deadly threat of systemic infections with coagulase negative <it>Staphylococcus lugdunensis </it>despite an appropriate antibiotic therapy has only recently been recognized. The predominant infectious focus observed so far is left-sided native heart valve endocarditis, but bone and soft tissue infections, septicaemia and vascular catheter-related bloodstream infections have also been reported. We present a patient with a fatal <it>Staphylococcus lugdunensis </it>septicaemia following zoster bacterial superinfection of the pelvic region.</p> <p>Case presentation</p> <p>A 71-year old male diagnosed with IgG kappa plasmocytoma presented with a conspicuous weight loss, a hypercalcaemic crisis and acute renal failure. After initiation of haemodialysis treatment his condition improved rapidly. However, he developed a varicella-zoster virus infection of the twelfth thoracic dermatome requiring intravenous acyclovir treatment. Four days later the patient presented with a fulminant septicaemia. Despite an early intravenous antibiotic therapy with ciprofloxacin, piperacillin/combactam and vancomycin the patient died within 48 hours, shortly before the infective isolate was identified as <it>Staphylococcus lugdunensis </it>by polymerase chain reaction.</p> <p>Conclusion</p> <p>Despite <it>S. lugdunensis </it>belonging to the family of coagulase-negative staphylococci with an usually low virulence, infections with <it>S. lugdunensis </it>may be associated with an aggressive course and high mortality. This is the first report on a <it>Staphylococcus lugdunensis </it>septicaemia following a zoster bacterial superinfection of the pelvic region.</p
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The association between frailty and MRI features of cerebral small vessel disease
Abstract: Frailty is a common syndrome in older individuals that is associated with poor cognitive outcome. The underlying brain correlates of frailty are unclear. The aim of this study was to investigate the association between frailty and MRI features of cerebral small vessel disease in a group of non-demented older individuals. We included 170 participants who were classified as frail (n = 30), pre-frail (n = 85) or non-frail (n = 55). The association of frailty and white matter hyperintensity volume and shape features, lacunar infarcts and cerebral perfusion was investigated by regression analyses adjusted for age and sex. Frail and pre-frail participants were older, more often female and showed higher white matter hyperintensity volume (0.69 [95%-CI 0.08 to 1.31], p = 0.03 respectively 0.43 [95%-CI: 0.04 to 0.82], p = 0.03) compared to non-frail participants. Frail participants showed a non-significant trend, and pre-frail participants showed a more complex shape of white matter hyperintensities (concavity index: 0.04 [95%-CI: 0.03 to 0.08], p = 0.03; fractal dimensions: 0.07 [95%-CI: 0.00 to 0.15], p = 0.05) compared to non-frail participants. No between group differences were found in gray matter perfusion or in the presence of lacunar infarcts. In conclusion, increased white matter hyperintensity volume and a more complex white matter hyperintensity shape may be structural brain correlates of the frailty phenotype
Heat shock protein-90-alpha, a prolactin-STAT5 target gene identified in breast cancer cells, is involved in apoptosis regulation
Introduction The prolactin-Janus-kinase-2-signal transducer and activator of transcription-5 (JAK2-STAT5) pathway is essential for the development and functional differentiation of the mammary gland. The pathway also has important roles in mammary tumourigenesis. Prolactin regulated target genes are not yet well defined in tumour cells, and we undertook, to the best of our knowledge, the first large genetic screen of breast cancer cells treated with or without exogenous prolactin. We hypothesise that the identification of these genes should yield insights into the mechanisms by which prolactin participates in cancer formation or progression, and possibly how it regulates normal mammary gland development. Methods We used subtractive hybridisation to identify a number of prolactin-regulated genes in the human mammary carcinoma cell line SKBR3. Northern blotting analysis and luciferase assays identified the gene encoding heat shock protein 90-alpha (HSP90A) as a prolactin-JAK2-STAT5 target gene, whose function was characterised using apoptosis assays. Results We identified a number of new prolactin-regulated genes in breast cancer cells. Focusing on HSP90A, we determined that prolactin increased HSP90A mRNA in cancerous human breast SKBR3 cells and that STAT5B preferentially activated the HSP90A promoter in reporter gene assays. Both prolactin and its downstream protein effector, HSP90α, promote survival, as shown by apoptosis assays and by the addition of the HSP90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), in both untransformed HC11 mammary epithelial cells and SKBR3 breast cancer cells. The constitutive expression of HSP90A, however, sensitised differentiated HC11 cells to starvation-induced wild-type p53-independent apoptosis. Interestingly, in SKBR3 breast cancer cells, HSP90α promoted survival in the presence of serum but appeared to have little effect during starvation. Conclusions In addition to identifying new prolactin-regulated genes in breast cancer cells, we found that prolactin-JAK2-STAT5 induces expression of the HSP90A gene, which encodes the master chaperone of cancer. This identifies one mechanism by which prolactin contributes to breast cancer. Increased expression of HSP90A in breast cancer is correlated with increased cell survival and poor prognosis and HSP90α inhibitors are being tested in clinical trials as a breast cancer treatment. Our results also indicate that HSP90α promotes survival depending on the cellular conditions and state of cellular transformation
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