Publications by authors named "Rikke R Hansen"

Background: Ants can become efficient biocontrol agents in plantation crops as they prey on pest insects and may inhibit plant pathogens by excreting broad-spectrum antibiotics. However, ants also provide a disservice by augmenting attended honeydew producing homopterans. This disservice may be avoided by offering ants artificial sugar as an alternative to honeydew.

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The effect of nitrogen and glyphosate on the plant community composition was investigated in a simulated field margin ecosystem. The plant community composition was inferred from pin-point cover data using a model-based ordination method that is suited for modelling pin-point cover data. The mean structure of the ordination model is analogous to a standard linear model, which enabled us to estimate the mean effects of nitrogen and glyphosate and their interaction in the two-dimensional ordination space.

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The Arctic is warming at twice the rate of the rest of the world. This impacts Arctic species both directly, through increased temperatures, and indirectly, through structural changes in their habitats. Species are expected to exhibit idiosyncratic responses to structural change, which calls for detailed investigations at the species and community level.

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Skeletal conditions are common causes of chronic pain and there is an unmet medical need for improved treatment options. Bone pain is currently managed with disease modifying agents and/or analgesics depending on the condition. Disease modifying agents affect the underlying pathophysiology of the disease and reduce as a secondary effect bone pain.

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Severe pain is a common and debilitating complication of metastatic bone cancer. Current analgesics provide insufficient pain relief and often lead to significant adverse effects. In models of cancer-induced bone pain, pathological sprouting of sensory fibers at the tumor-bone interface occurs concomitantly with reactive astrocytosis in the dorsal horn of the spinal cord.

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The response of body size to increasing temperature constitutes a universal response to climate change that could strongly affect terrestrial ectotherms, but the magnitude and direction of such responses remain unknown in most species. The metabolic cost of increased temperature could reduce body size but long growing seasons could also increase body size as was recently shown in an Arctic spider species. Here, we present the longest known time series on body size variation in two High-Arctic butterfly species: Boloria chariclea and Colias hecla.

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Treatment of chronic pain remains a clinical challenge and sufficient pharmacological management is difficult to achieve without concurrent adverse drug effects. Recently the concept of chronic pain as a solely neuron-mediated phenomenon has evolved and it is now appreciated that also glial cells are of critical importance in pain generation and modulation. Astrocytes are macroglial cells that have close structural relationships with neurons; they contact neuronal somata and dendrites and enwrap synapses, where small astrocytic processes have been shown to be highly motile.

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GAB(A) (γ-aminobutyric acid) is abundantly expressed within the brain, and spinal cord pain circuits where it acts as the principal mediator of fast inhibitory neurotransmission. However, drugs that target GABA(A) receptor function such as the classical benzodiazepines have not been optimised to promote analgesia, are limited by side effects and are not routinely used for this purpose in humans. Compounds such as NS11394, L-838,417, HZ166 and TPA023 all bind to the same benzodiazepine site on the GABA(A) receptor to allosterically modulate receptor function and enhance the actions of GABA.

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GABA-A receptor positive allosteric modulators (PAMs) mediate robust analgesia in animal models of pathological pain, in part via enhancing injury-induced loss of GABA-A-α2 and -α3 receptor function within the spinal cord. As yet, a lack of clinically suitable tool compounds has prevented this concept being tested in humans. Prior to assessing the efficacy of GABA-A receptor PAMs in a human volunteer pain model we have compared compounds capable of variously modulating GABA-A receptor function in comparable rat models of capsaicin-induced acute nocifensive flinching behaviour and secondary mechanical hypersensitivity.

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The purinergic P2X3 and P2X2/3 receptors are in the peripheral nervous system almost exclusively confined to afferent sensory neurons, where they are found both at peripheral and central synapses. The P2X3 receptor is implicated in both neuropathic and inflammatory pain. However, the role of the P2X3 receptor in chronic cancer-induced bone pain is less known.

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The purinergic P2X7 receptor is implicated in both neuropathic and inflammatory pain, and has been suggested as a possible target in pain treatment. However, the specific role of the P2X7 receptor in bone cancer pain is unknown. We demonstrated that BALB/cJ P2X7 receptor knockout (P2X7R KO) mice were susceptible to bone cancer pain and moreover had an earlier onset of pain-related behaviours compared with cancer-bearing, wild-type mice.

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Prostate, breast and lung cancers readily develop bone metastases which lead to fractures, hypercalcemia and pain. Malignant growth in the bones depends on osteoclast-mediated bone resorption and in this regard bisphosphonate compounds, which have high-bone affinity and inhibit osteoclast activity, have been found to alleviate bone cancer symptoms. In this study, the bisphosphonate risedronate and its phosphonocarboxylate derivative NE-10790 was tested in a murine bone cancer pain model.

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Liquid manure (slurry) storages are sources of gases such as ammonia (NH(3)) and methane (CH(4)). Danish slurry storages are required to be covered to reduce NH(3) emissions and often a floating crust of straw is applied. This study investigated whether physical properties of the crust or crust microbiology had an effect on the emission of the potent greenhouse gases CH(4) and nitrous oxide (N(2)O) when crust moisture was manipulated ("dry", "moderate", and "wet").

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Pain due to bone malignancies is one of the most difficult types of cancer pain to fully control and may further decrease the patients' quality of life. Animal models of chronic pain conditions resulting from peripheral inflammatory reactions or nerve injuries are responsive to treatment with cannabinoid agonists. However, the use of cannabinoid agonists in humans may be hampered by CNS related side effects and development of tolerance.

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Activation of spinal cord microglia and astrocytes is a common phenomenon in nerve injury pain models and is thought to exacerbate pain perception. Following a nerve injury, a transient increase in the presence of microglia takes place while the increased numbers of astrocytes stay elevated for an extended period of time. It has been proposed that activated microglia are crucial for the development of neuropathic pain and that they lead to activation of astrocytes which then play a role in maintaining the long term pathological pain sensation.

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Objective: This article deals with the issue of ordinary healthy people using drugs to improve or enhance non-disease conditions. The objective is to illuminate the extent of public acceptance of this practice.

Research Design And Methods: The results are based on two studies: a classically structured telephone interview with 961 Danes in 1999 and an Internet questionnaire survey of 2735 Danes in 2003.

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