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Sample records for experimental pain models

  1. A human experimental model of episodic pain

    DEFF Research Database (Denmark)

    Petrini, Laura; Hennings, Kristian; Li, Xi

    2014-01-01

    were subjected to 45 min of intense painful cutaneous electrical stimulation (episodic pain session), using a stimulus paradigm that in animals has been shown to induce long-term potentiation. These electrical stimulations produced a verbal pain rating of approximately 85 on a 0-100 verbal rating scale......An experimental model of daily episodic pain was developed to investigate peripheral sensitization and cortical reorganization in healthy individuals. Two experiments (A and B) were conducted. Experiments A and B consisted of one and five consecutive days, respectively, in which the participants...... (VRS). Physiological (blood flow and axon flare reflex), psychophysical (perception threshold and verbal pain ratings) and electrophysiological (128 channels recorded somatosensory evoked potential (SEP)) measurements were recorded. The stimulation evoked a visible axon flare reflex and caused...

  2. Associations between psychological variables and pain in experimental pain models. A systematic review

    DEFF Research Database (Denmark)

    Hansen, M S; Horjales-Araujo, E; Dahl, J B

    2015-01-01

    are predictive of the level of pain following experimental pain models. METHODS: A systematic search on the databases, PubMed, Embase, Cochcrane library, and Clinicaltrials.gov was performed during September 2014. All trials investigating the association between psychological variables and experimental pain...... and experimental pain. CONCLUSION: Psychological factors may have predictive value when investigating experimental pain. However, due to substantial heterogeneity and methodological shortcomings of the published literature, firm conclusions are not possible.......BACKGROUND: The association between pain and psychological characteristics has been widely debated. Thus, it remains unclear whether an individual's psychological profile influences a particular pain experience, or if previous pain experience contributes to a certain psychological profile...

  3. Mechanisms of Osteoarthritic Pain. Studies in Humans and Experimental Models

    Directory of Open Access Journals (Sweden)

    Annett Eitner

    2017-11-01

    Full Text Available Pain due to osteoarthritis (OA is one of the most frequent causes of chronic pain. However, the mechanisms of OA pain are poorly understood. This review addresses the mechanisms which are thought to be involved in OA pain, derived from studies on pain mechanisms in humans and in experimental models of OA. Three areas will be considered, namely local processes in the joint associated with OA pain, neuronal mechanisms involved in OA pain, and general factors which influence OA pain. Except the cartilage all structures of the joints are innervated by nociceptors. Although the hallmark of OA is the degradation of the cartilage, OA joints show multiple structural alterations of cartilage, bone and synovial tissue. In particular synovitis and bone marrow lesions have been proposed to determine OA pain whereas the contribution of the other pathologies to pain generation has been studied less. Concerning the peripheral neuronal mechanisms of OA pain, peripheral nociceptive sensitization was shown, and neuropathic mechanisms may be involved at some stages. Structural changes of joint innervation such as local loss and/or sprouting of nerve fibers were shown. In addition, central sensitization, reduction of descending inhibition, descending excitation and cortical atrophies were observed in OA. The combination of different neuronal mechanisms may define the particular pain phenotype in an OA patient. Among mediators involved in OA pain, nerve growth factor (NGF is in the focus because antibodies against NGF significantly reduce OA pain. Several studies show that neutralization of interleukin-1β and TNF may reduce OA pain. Many patients with OA exhibit comorbidities such as obesity, low grade systemic inflammation and diabetes mellitus. These comorbidities can significantly influence the course of OA, and pain research just began to study the significance of such factors in pain generation. In addition, psychologic and socioeconomic factors may aggravate

  4. Endogenous opioid antagonism in physiological experimental pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Pereira, Manuel P; Andersen, Lars Peter H

    2015-01-01

    Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double...... hyperalgesia models (6 studies), 'pain' models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and r......TMS. In the remaining 14 conditioning modulation studies either absence of effects or ambiguous effects by MOR-antagonists, were observed. In the STP-studies, no effect of the opioid-blockade could be demonstrated in 5 out of 6 secondary hyperalgesia studies. The direction of MOR-antagonist dependent effects upon pain...

  5. Modelling concentration-analgesia relationships for morphine to evaluate experimental pain models

    DEFF Research Database (Denmark)

    Sverrisdóttir, Eva; Foster, David John Richard; Upton, Richard Neil

    2015-01-01

    -blind, placebo-controlled, crossover study, 39 healthy volunteers received an oral dose of 30 mg morphine hydrochloride or placebo. Non-linear mixed effects modelling was used to describe the plasma concentrations of morphine and metabolites, and the analgesic effect of morphine on experimental pain in skin......The aim of this study was to develop population pharmacokinetic-pharmacodynamic models for morphine in experimental pain induced by skin heat and muscle pressure, and to evaluate the experimental pain models with regard to assessment of morphine pharmacodynamics. In a randomized, double...... and muscle. Baseline pain metrics varied between individuals and occasions, and were described with interindividual and interoccasion variability. Placebo-response did not change with time. For both pain metrics, morphine effect was proportional to baseline pain and was described with a linear model...

  6. Assessment of knee joint pain in experimental rodent models of osteoarthritis.

    Science.gov (United States)

    Piel, Margaret J; Kroin, Jeffrey S; Im, Hee-Jeong

    2015-01-01

    Pain assessment in animal models of osteoarthritis is integral to interpretation of a model's utility in representing the clinical condition, and enabling accurate translational medicine. Here we describe two methods for behavioral pain assessments available for use in animal models of experimental osteoarthritic pain: Von Frey filaments and spontaneous activity monitoring.

  7. Translational pain research: evaluating analgesic effect in experimental visceral pain models

    DEFF Research Database (Denmark)

    Olesen, Anne Estrup; Andresen, Trine; Christrup, Lona Louring

    2009-01-01

    facilitate minimizing the gap between knowledge gained in animal and human clinical studies. Combining experimental pain studies and pharmacokinetic studies can improve understanding of the pharmacokinetic-pharmacodynamic relationship of analgesics and, thus, provide valuable insight into optimal clinical...... analgesics in detail. In combination with pharmacokinetic studies and objective assessment such as electroencephalography, new information regarding a given drug substance and its effects can be obtained. Results from experimental human visceral pain research can bridge the gap in knowledge between animal......Deep visceral pain is frequent and presents major challenges in pain management, since its pathophysiology is still poorly understood. One way to optimize treatment of visceral pain is to improve knowledge of the mechanisms behind the pain and the mode of action of analgesic substances. This can...

  8. Experimental human pain models: a review of standardised methods for preclinical testing of analgesics.

    Science.gov (United States)

    Staahl, Camilla; Drewes, Asbjørn Mohr

    2004-09-01

    Treatment of pain is one of the major challenges in clinical medicine. However, it is often difficult to evaluate the effect of a treatment, as the many symptoms of the underlying diseases often confound this assessment. Furthermore, as the pain mechanisms in many diseases are poorly understood, the limited successful trial and error approach is most often used in the selection of analgesics. Hence, there is a need for new methods in the characterization and treatment of pain. Human experimental pain models offer the possibility to explore the pain system under controlled settings. The models can also be used to screen the analgesic profiles of drugs targeted to treat pain. This review gives a brief introduction to the methods used to evoke and assess pain in the skin, muscle and viscera. New methods using multimodal stimulation and activation of central pain mechanisms can to a higher degree mimic the clinical situation, and such methods are recommended in the future screening of analgesics. Examples of the use of experimental pain models in the testing of analgesics are given. With these models the therapeutic spectrum may be defined from a differentiated knowledge on the effect of drugs on the pain system. Such information may be used in the future guidelines for trials and clinical use of analgesics.

  9. Tryptase-PAR2 axis in experimental autoimmune prostatitis, a model for chronic pelvic pain syndrome.

    Science.gov (United States)

    Roman, Kenny; Done, Joseph D; Schaeffer, Anthony J; Murphy, Stephen F; Thumbikat, Praveen

    2014-07-01

    Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) affects up to 15% of the male population and is characterized by pelvic pain. Mast cells are implicated in the murine experimental autoimmune prostatitis (EAP) model as key to chronic pelvic pain development. The mast cell mediator tryptase-β and its cognate receptor protease-activated receptor 2 (PAR2) are involved in mediating pain in other visceral disease models. Prostatic secretions and urines from CP/CPPS patients were examined for the presence of mast cell degranulation products. Tryptase-β and PAR2 expression were examined in murine EAP. Pelvic pain and inflammation were assessed in the presence or absence of PAR2 expression and upon PAR2 neutralization. Tryptase-β and carboxypeptidase A3 were elevated in CP/CPPS compared to healthy volunteers. Tryptase-β was capable of inducing pelvic pain and was increased in EAP along with its receptor PAR2. PAR2 was required for the development of chronic pelvic pain in EAP. PAR2 signaling in dorsal root ganglia led to extracellular signal-regulated kinase (ERK)1/2 phosphorylation and calcium influx. PAR2 neutralization using antibodies attenuated chronic pelvic pain in EAP. The tryptase-PAR2 axis is an important mediator of pelvic pain in EAP and may play a role in the pathogenesis of CP/CPPS. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  10. Comparative efficacy of oral meloxicam and phenylbutazone in 2 experimental pain models in the horse.

    Science.gov (United States)

    Banse, Heidi; Cribb, Alastair E

    2017-02-01

    The efficacy of oral phenylbutazone [PBZ; 4.4 mg/kg body weight (BW), q12h], a non-selective non-steroidal anti-inflammatory drug (NSAID), and oral meloxicam (MXM; 0.6 mg/kg BW, q24h), a COX-2 selective NSAID, were evaluated in 2 experimental pain models in horses: the adjustable heart bar shoe (HBS) model, primarily representative of mechanical pain, and the lipopolysaccharide-induced synovitis (SYN) model, primarily representative of inflammatory pain. In the HBS model, PBZ reduced multiple indicators of pain compared with the placebo and MXM. Meloxicam did not reduce indicators of pain relative to the placebo. In the SYN model, MXM and PBZ reduced increases in carpal skin temperature compared to the placebo. Meloxicam reduced lameness scores and lameness-induced changes in head movement compared to the placebo and PBZ. Phenylbutazone reduced lameness-induced change in head movement compared to the placebo. Overall, PBZ was more effective than MXM at reducing pain in the HBS model, while MXM was more effective at reducing pain in the SYN model at the oral doses used.

  11. Opioid pathways activation mediates the activity of nicorandil in experimental models of nociceptive and inflammatory pain.

    Science.gov (United States)

    Dutra, Marcela M G B; Nascimento Júnior, Elias B; Godin, Adriana M; Brito, Ana Mercy S; Melo, Ivo S F; Augusto, Paulo S A; Rodrigues, Felipe F; Araújo, Débora P; de Fátima, Ângelo; Coelho, Márcio M; Machado, Renes R

    2015-12-05

    We have previously demonstrated that nicorandil inhibits the second phase of the nociceptive response induced by formaldehyde. In the present study, we evaluated the effects induced by nicorandil in other models of nociceptive and inflammatory pain in mice and also whether opioid pathways activation mediates its activity. As we have previously demonstrated, per os (p.o.) administration of nicorandil (50, 100 or 150mg/kg; -1h) inhibited the second phase of the nociceptive response induced by intraplantar (i.pl.) injection of formaldehyde. Nicorandil (50, 100 or 150mg/kg; p.o., -1h) also exhibited activity in models of inflammatory pain induced by i.pl. injection of carrageenan (300μg) and nociceptive pain induced by exposure to noxious heat (50°C). Intraperitoneal (i.p.) administration of the opioid antagonist naltrexone (1, 5 or 10mg/kg, -30min) attenuated or abolished the antinociceptive activity of nicorandil (100mg/kg, p.o.) in the three experimental pain models. In conclusion, we demonstrate that nicorandil exhibits activity in different models of nociceptive and inflammatory pain. The demonstration that the antinociceptive effect induced by nicorandil is markedly attenuated by an opioid antagonist provides solid information about an important mechanism mediating the activity of this antianginal drug. Altogether, our data suggest that the clinical pain relief induced by nicorandil in heart ischemic conditions may result from both vasodilation and intrinsic analgesic activity. Copyright © 2015. Published by Elsevier B.V.

  12. Endogenous opioid antagonism in physiological experimental pain models: a systematic review.

    Directory of Open Access Journals (Sweden)

    Mads U Werner

    Full Text Available Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR antagonists in placebo-controlled, double-blind studies using 'inhibitory' or 'sensitizing', physiological test paradigms in healthy human subjects. The databases PubMed and Embase were searched according to predefined criteria. Out of a total of 2,142 records, 63 studies (1,477 subjects [male/female ratio = 1.5] were considered relevant. Twenty-five studies utilized 'inhibitory' test paradigms (ITP and 38 studies utilized 'sensitizing' test paradigms (STP. The ITP-studies were characterized as conditioning modulation models (22 studies and repetitive transcranial magnetic stimulation models (rTMS; 3 studies, and, the STP-studies as secondary hyperalgesia models (6 studies, 'pain' models (25 studies, summation models (2 studies, nociceptive reflex models (3 studies and miscellaneous models (2 studies. A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and rTMS. In the remaining 14 conditioning modulation studies either absence of effects or ambiguous effects by MOR-antagonists, were observed. In the STP-studies, no effect of the opioid-blockade could be demonstrated in 5 out of 6 secondary hyperalgesia studies. The direction of MOR-antagonist dependent effects upon pain ratings, threshold assessments and somatosensory evoked potentials (SSEP, did not appear consistent in 28 out of 32 'pain' model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect, presumably mediated by an EOS-dependent mechanisms of analgesia and hyperalgesia.

  13. The Animal Model of Spinal Cord Injury as an Experimental Pain Model

    OpenAIRE

    Aya Nakae; Kunihiro Nakai; Kenji Yano; Ko Hosokawa; Masahiko Shibata; Takashi Mashimo

    2011-01-01

    Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of patholo...

  14. Pharmacodynamic Modelling of Placebo and Buprenorphine Effects on Event-Related Potentials in Experimental Pain

    DEFF Research Database (Denmark)

    Juul, Rasmus V; Foster, David J R; Upton, Richard N

    2014-01-01

    The purpose of the study was to investigate placebo and buprenorphine effects on event-related potentials (ERPs) in experimental pain and the potential benefit of population pharmacodynamic modelling in data analysis. Nineteen healthy volunteers received transdermal placebo and buprenorphine......-effects modelling implemented in NONMEM (V7.2.0.). Pharmacodynamic models were developed to adequately describe both placebo and buprenorphine ERP data. Models predicted significant placebo effects, but did not predict significant effects related to buprenorphine concentration. Models revealed that ERPs varied both...

  15. Inflammatory pain in experimental burns in man

    DEFF Research Database (Denmark)

    Pedersen, J L

    2000-01-01

    demonstrated in animal models. Most often clinical pain is due to tissue damage leading to acute inflammation and hyperalgesia, but only few human pain models have examined pain responses in injured tissues. Therefore, models with controlled and reversible tissue trauma are needed. The human burn model......Human experimental pain models are important tools in pain research. The primary aims of pain research in normal man is 1) to provide insight in pain mechanisms, 2) to provide a rational basis for clinical trials of pain relieving interventions, and 3) to confirm the anti-nociceptive effects...... is an example of such a model, and several groups have performed studies of analgesics and pain mechanisms based on the model. The thesis aims to provide a critical review of the human burn model as a tool in pain research, and to give suggestions for development of the model and future research. The pain...

  16. Pain in experimental autoimmune encephalitis: a comparative study between different mouse models

    Directory of Open Access Journals (Sweden)

    Lu Jianning

    2012-10-01

    Full Text Available Abstract Background Pain can be one of the most severe symptoms associated with multiple sclerosis (MS and develops with varying levels and time courses. MS-related pain is difficult to treat, since very little is known about the mechanisms underlying its development. Animal models of experimental autoimmune encephalomyelitis (EAE mimic many aspects of MS and are well-suited to study underlying pathophysiological mechanisms. Yet, to date very little is known about the sensory abnormalities in different EAE models. We therefore aimed to thoroughly characterize pain behavior of the hindpaw in SJL and C57BL/6 mice immunized with PLP139-151 peptide or MOG35-55 peptide respectively. Moreover, we studied the activity of pain-related molecules and plasticity-related genes in the spinal cord and investigated functional changes in the peripheral nerves using electrophysiology. Methods We analyzed thermal and mechanical sensitivity of the hindpaw in both EAE models during the whole disease course. Qualitative and quantitative immunohistochemical analysis of pain-related molecules and plasticity-related genes was performed on spinal cord sections at different timepoints during the disease course. Moreover, we investigated functional changes in the peripheral nerves using electrophysiology. Results Mice in both EAE models developed thermal hyperalgesia during the chronic phase of the disease. However, whereas SJL mice developed marked mechanical allodynia over the chronic phase of the disease, C57BL/6 mice developed only minor mechanical allodynia over the onset and peak phase of the disease. Interestingly, the magnitude of glial changes in the spinal cord was stronger in SJL mice than in C57BL/6 mice and their time course matched the temporal profile of mechanical hypersensitivity. Conclusions Diverse EAE models bearing genetic, clinical and histopathological heterogeneity, show different profiles of sensory and pathological changes and thereby enable

  17. Pain hypersensitivity in rats with experimental autoimmune neuritis, an animal model of human inflammatory demyelinating neuropathy.

    Science.gov (United States)

    Moalem-Taylor, Gila; Allbutt, Haydn N; Iordanova, Mihaela D; Tracey, David J

    2007-07-01

    Experimental autoimmune neuritis (EAN) is a T cell mediated autoimmune disease of the peripheral nervous system that serves as an animal model of the acute inflammatory demyelinating polyradiculoneuropathy in Guillain-Barre syndrome (GBS). Although pain is a common symptom of GBS occurring in 55-85% of cases, it is often overlooked and the underlying mechanisms are poorly understood. Here we examined whether animals with EAN exhibit signs of neuropathic pain including hyperalgesia and allodynia, and assessed their peripheral nerve autoimmune inflammation. We immunized Lewis rats with peripheral myelin P2 peptide (amino acids 57-81) emulsified with complete Freund's adjuvant, or with adjuvant only as control. P2-immunized rats developed mild to modest monophasic EAN with disease onset at day 8, peak at days 15-17, and full recovery by day 28 following immunization. Rats with EAN showed a significant decrease in withdrawal latency to thermal stimuli and withdrawal threshold to mechanical stimuli, in both hindpaws and forepaws, during the course of the disease. We observed a significant infiltration of T cells bearing alphabeta receptors, and a significant increase in antigen-presenting cells expressing MHC class II as well as macrophages, in EAN-affected rats. Our results demonstrate that animals with active EAN develop significant thermal hyperalgesia and mechanical allodynia, accompanied by pronounced autoimmune inflammation in peripheral nerves. These findings suggest that EAN is a useful model for the pain seen in many GBS patients, and may facilitate study of neuroimmune mechanisms underlying pain in autoimmune neuropathies.

  18. No release of interstitial glutamate in experimental human model of muscle pain

    DEFF Research Database (Denmark)

    Ashina, M.; Jørgensen, M.; Stallknecht, Bente

    2005-01-01

    Glutamate may be released from muscle nociceptors and thereby contribute to mechanisms underlying acute and chronic muscle pain. In vivo concentration of glutamate during muscle pain has not previously been studied in either animals or humans. In the present study, we aimed to study the in vivo...... flow increased significantly over time in response to infusion of chemical mixture and placebo (p = 0.001). However, we found no difference in changes in muscle blood flow between chemical mixture and placebo (p > 0.05). In conclusion, the present study demonstrates no signs of increased release...... of glutamate from myofascial nociceptors during and after acute experimentally induced muscle pain and tenderness....

  19. Experimental tooth clenching. A model for studying mechanisms of muscle pain.

    Science.gov (United States)

    Dawson, Andreas

    2013-01-01

    The overall goal of this thesis was to broaden knowledge of pain mechanisms in myofascial temporomandibular disorders (M-TMD). The specific aims were to: Develop a quality assessment tool for experimental bruxism studies (study I). Investigate proprioceptive allodynia after experimental tooth clenching exercises (study II). Evaluate the release of serotonin (5-HT), glutamate, pyruvate, and lactate in healthy subjects (study III) and in patients with M-TMD (study IV), after experimental tooth clenching exercises. In (I), tool development comprised 5 steps: (i) preliminary decisions, (ii) item generation, (iii) face-validity assessment, (iv) reliability and discriminative validity testing, and (v) instrument refinement. After preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was generated. Eleven experts were invited to participate on the Delphi panel, of which 10 agreed. After four Delphi rounds, 8 items remained and were included in the Quality Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS). Inter-observer reliability was acceptable (k = 0.77), and discriminative validity high (phi coefficient 0.79; P muscle blood flow. Two hours after the start of microdialysis, participants were randomized to a 20-min repetitive experimental tooth clenching task (50% of MVCF) or a control session (no clenching). Pain intensity was measured throughout the experiment. Substance levels and blood flow were unaltered at all time points between sessions, and between genders in each session. Pain intensity was significantly higher after clenching in the clenching session compared to the same time point in the control session. In (IV), 15 patients with M-TMD and 15 healthy controls participated in one session and the methodology described above was used. M-TMD patients had significantly higher levels of 5-HT and significantly lower blood flows than healthy controls. No significant differences for any substance at any

  20. IL-17 is not essential for inflammation and chronic pelvic pain development in an experimental model of chronic prostatitis/chronic pelvic pain syndrome.

    Science.gov (United States)

    Motrich, Ruben D; Breser, María L; Sánchez, Leonardo R; Godoy, Gloria J; Prinz, Immo; Rivero, Virginia E

    2016-03-01

    Pain and inflammation in the absence of infection are hallmarks in chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) patients. The etiology of CP/CPPS is unclear, and autoimmunity has been proposed as a cause. Experimental autoimmune prostatitis (EAP) models have long been used for studying CP/CPPS. Herein, we studied prostate inflammation induction and chronic pelvic pain development in EAP using IL-12p40-KO, IL-4-KO, IL-17-KO, and wild-type (C57BL/6) mice. Prostate antigen (PAg) immunization in C57BL/6 mice induced specific Th1 and Th17 immune responses and severe prostate inflammation and cell infiltration, mainly composed of CD4 T cells and macrophages. Moreover, chronic pelvic pain was evidenced by increased allodynia responses. In immunized IL-17-KO mice, the presence of a prominent PAg-specific Th1 immune response caused similar prostate inflammation and chronic pelvic pain. Furthermore, markedly high PAg-specific Th1 immune responses, exacerbated prostate inflammation, and chronic pelvic pain were detected in immunized IL-4-KO mice. Conversely, immunized IL-12p40-KO mice developed PAg-specific Th2 immune responses, characterized by high IL-4 secretion and neither infiltration nor damage in the prostate. As observed in wild-type control animals, IL12p40-KO mice did not evidence tactile allodynia responses. Our results suggest that, as in patients, chronic pelvic pain is a consequence of prostate inflammation. After PAg immunization, a Th1-associated immune response develops and induces prostate inflammation and chronic pelvic pain. The absence of Th1 or Th2 cytokines, respectively, diminishes or enhances EAP susceptibility. In addition, IL-17 showed not to be essential for pathology induction and chronic pelvic pain development.

  1. Modelling the PKPD of oxycodone in experimental pain - Impact of opioid receptor polymorphisms

    DEFF Research Database (Denmark)

    Olsen, Rasmus; Foster, David J R; Upton, Richard N

    2016-01-01

    BACKGROUND: Polymorphisms in the opioid receptor genes may affect the pharmacodynamics (PD) of oxycodone and be part of the reason behind the diversity in clinical response. The aim of the analysis was to model the exposure-response profile of oxycodone for three different pain variables and sear...

  2. Much Pain, Little Gain? Paradigm-Specific Models and Methods in Experimental Psychology.

    Science.gov (United States)

    Meiser, Thorsten

    2011-03-01

    Paradigm-oriented research strategies in experimental psychology have strengths and limitations. On the one hand, experimental paradigms play a crucial epistemic and heuristic role in basic psychological research. On the other hand, empirical research is often limited to the observed effects in a certain paradigm, and theoretical models are frequently tied to the particular features of the given paradigm. A paradigm-driven research strategy therefore jeopardizes the pursuit of research questions and theoretical models that go beyond a specific paradigm. As one example of a more integrative approach, recent research on illusory and spurious correlations has attempted to overcome the limitations of paradigm-specific models in the context of biased contingency perception and social stereotyping. Last but not least, the use of statistical models for the analysis of elementary cognitive functions is a means toward a more integrative terminology and theoretical perspective across different experimental paradigms and research domains. © The Author(s) 2011.

  3. Differential effects of repeated low dose treatment with the cannabinoid agonist WIN 55,212-2 in experimental models of bone cancer pain and neuropathic pain

    DEFF Research Database (Denmark)

    Hald, Andreas; Ding, Ming; Egerod, Kristoffer Lihme

    2008-01-01

    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. In the present study, we investigated the effect of repeated low dose administration of the synthetic cannabinoid agonist WIN 55,212-2 on bone cancer pain...... and neuropathic pain in mice. In addition, we investigated the development of CNS related side effects and tolerance. We found that 0.5 mg/kg/day for 18 days reduced pain related behavior and expression of spinal glial fibrillary acidic protein in the bone cancer pain model but not in the neuropathic pain model...

  4. Citral: a monoterpene with prophylactic and therapeutic anti-nociceptive effects in experimental models of acute and chronic pain.

    Science.gov (United States)

    Nishijima, Catarine M; Ganev, Ellen G; Mazzardo-Martins, Leidiane; Martins, Daniel F; Rocha, Lúcia R M; Santos, Adair R S; Hiruma-Lima, Clelia A

    2014-08-05

    Citral (3,7-dimethyl-2,6-octadienal) is an open-chain monoterpenoid present in the essential oils of several medicinal plants. The aim of this work was to evaluate the effects of orally administered citral in experimental models of acute and chronic nociception, inflammation, and gastric ulcers caused by non-steroidal anti-inflammatory drugs (NSAIDs). Oral treatment with citral significantly inhibited the neurogenic and inflammatory pain responses induced by intra-plantar injection of formalin. Citral also had prophylactic and therapeutic anti-nociceptive effects against mechanical hyperalgesia in plantar incision surgery, chronic regional pain syndrome, and partial ligation of sciatic nerve models, without producing any significant motor dysfunction. In addition, citral markedly attenuated the pain response induced by intra-plantar injection of glutamate and phorbol 12-myristate 13-acetate (PMA, a protein kinase C activator), as well as by intrathecal (i.t.) injection of ionotropic and metabotropic glutamate receptor agonists (N-methyl-D-aspartic acid [NMDA] and 1-amino-1,3-dicarboxycyclopentane [trans-ACPD], respectively), substance P, and cytokine tumour necrosis factor-α. However, citral potentiated behaviours indicative of pain caused by i.t., but not intra-plantar, injection of a transient receptor potential vanilloid receptor type 1 (TRPV1) agonist. Finally, the anti-nociceptive action of citral was found to involve significant activation of the 5-HT2A serotonin receptor. The effect of citral was accompanied by a gastro-protective effect against NSAID-induced ulcers. Together, these results show the potential of citral as a new drug for the treatment of pain. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effects of gabapentin on experimental somatic pain and temporal summation

    DEFF Research Database (Denmark)

    Arendt-Nielsen, Lars; Frøkjaer, Jens Brøndum; Staahl, Camilla

    2007-01-01

    BACKGROUND AND OBJECTIVES: Gabapentin is used for treatment of neuropathic pain, but its effect on different somatic pain modalities and integrative mechanisms are not completely understood. The aim of this double-blind, placebo-controlled experimental pain study, conducted on 20 healthy volunteers......, was to examine the effect of a single dose of 1200 mg gabapentin on multi-modal experimental cutaneous and muscle pain models. METHODS: The following pain models were applied: (1) pain thresholds to single and repeated cutaneous and intramuscular electrical stimulation (temporal summation to 5 stimuli delivered...

  6. Influence of Murraya koenigii on experimental model of diabetes and progression of neuropathic pain

    Science.gov (United States)

    Tembhurne, S.V.; Sakarkar, D.M.

    2010-01-01

    The aim of the present study was to evaluate the effect of ethanolic extract of Murraya koenigii leaves (MKL) on blood glucose level and in prevention or management of diabetic neuropathy. In the present study the diabetic neuropathy was developed 9 weeks after single injection of streptozotocin (STZ, 70 mg/kg i.v.) in rat. The treatment with MKL (300 and 500 mg/kg p.o.) was started after stabilization of blood glucose level (13 days after STZ) and evaluated for determination of glycemic level, glycated haemoglobin, grip strength, pain sensitivity and threshold. The result showed that the treatment with MKL possessed hypoglycemic effect in diabetic treated animals. The results also indicated that the decreases in the grip strength in diabetic animals represented the induction of neuropathy 9 weeks after STZ treatment. Prior treatments with MKL increased the grip strength of diabetic rats. The results of pain sensitivity indicated the loss of pain perception in diabetic animals because of nerve damage. While prior treatment with MKL upto 9 week in diabetic animals resulted in the increase in the licking time and withdrawal latency in hot plate and tail flick tests, respectively, which indicates the presence of pain perception and prevention of nerve damage due to protective effect of MKL in progression of diabetic neuropathic pain. Therefore, the present study concludes that the chronic treatment with MKL significantly decreased the glycemic level as well as it protected the animals against development of diabetic neuropathy. PMID:21589767

  7. Effect of ethanolic extracts of Justicia neesii Ramam. against experimental models of pain and pyrexia.

    Science.gov (United States)

    Sridhar, Nimmakayala; Lakshmi, Duggirala Suguna; Goverdhan, Puchchakayala

    2015-01-01

    The main objective of this study is to evaluate the analgesic and anti-pyretic activities of ethanolic extracts of Justicia neesii Ramam. by different experimental models. The analgesic activity of plant extract was evaluated against thermal and chemical stimulus induced by Eddy's hot plate and acetic acid respectively in mice. Brewer's yeast induced pyrexia was used to evaluate the antipyretic activity in rats and TAB vaccine induced pyrexia was used to evaluate the antipyretic activity in rabbits. In the hot plate model 400 mg/kg p.o. dose of J. neesii has shown its maximal effect at 3 h. The results are significant (P < 0.05) and comparable to the values of standard drug pentazocine (30 mg/kg i.p.). In acetic acid induced writhing model 400 mg/kg p.o. of plant extracts have shown highly significant activity (P < 0.001) and better than standard drug indomethacin (10 mg/kg p.o.). The 400 mg/kg p.o. dose of plant extract has given significant results against both yeast induced pyrexia and TAB vaccine induced pyrexia (P< 0.01 and 0.05 respectively). These values are comparable to that of paracetamol 100 mg/kg p.o. standard dose. This study shows that the ethanol extract of J. neesii has significant analgesic and antipyretic activity.

  8. Pain assessment in animal models of osteoarthritis.

    Science.gov (United States)

    Piel, Margaret J; Kroin, Jeffrey S; van Wijnen, Andre J; Kc, Ranjan; Im, Hee-Jeong

    2014-03-10

    Assessment of pain in animal models of osteoarthritis is integral to interpretation of a model's utility in representing the clinical condition, and enabling accurate translational medicine. Here we describe behavioral pain assessments available for small and large experimental osteoarthritic pain animal models. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. The hypoalgesic effect of oxycodone in human experimental pain models in relation to the CYP2D6 oxidation polymorphism

    DEFF Research Database (Denmark)

    Zwisler, Stine T; Enggaard, Thomas P; Noehr-Jensen, Lene

    2009-01-01

    Oxycodone is O-demethylated by CYP2D6 to oxymorphone which is a potent micro-receptor agonist. The CYP2D6 oxidation polymorphism divides the Caucasian population in two phenotypes: approximately 8% with no enzyme activity, poor metabolizers (PM) and the remainder with preserved CYP2D6 activity......, extensive metabolizers (EM). The objective of the study was to determine if the analgesic effect of oxycodone in human experimental pain depends on its metabolism to oxymorphone. The analgesic effect of oxycodone was evaluated in a randomized, placebo-controlled, double-blinded, crossover experiment...... including 33 (16 EM and 17 PM) healthy volunteers. Pain tests were performed before and 1, 2, 3 and 4 hr after medication and included pain detection and tolerance thresholds to single electrical sural nerve stimulation, pain summation threshold to repetitive electrical sural nerve stimulation and the cold...

  10. Association between Gene Polymorphisms and Pain Sensitivity Assessed in a Multi-Modal Multi-Tissue Human Experimental Model - An Explorative Study

    DEFF Research Database (Denmark)

    Nielsen, Lecia Møller; Olesen, Anne Estrup; Sato, Hiroe

    2016-01-01

    The genetic influence on sensitivity to noxious stimuli (pain sensitivity) remains controversial and needs further investigation. In the present study, the possible influence of polymorphisms in three opioid receptor (OPRM, OPRD and OPRK) genes and the catechol-O-methyltransferase (COMT) gene...... on pain sensitivity in healthy participants was investigated. Catechol-O-methyltransferase has an indirect effect on the mu opioid receptor by changing its activity through an altered endogenous ligand effect. Blood samples for genetic analysis were withdrawn in a multi-modal and multi-tissue experimental...... pain model in 40 healthy participants aged 20-65. Seventeen different single nucleotide polymorphisms in different genes (OPRM, OPRK, OPRD and COMT) were included in the analysis. Experimental pain tests included thermal skin stimulation, mechanical muscle and bone stimulation and mechanical...

  11. Experimental knee pain reduces muscle strength

    DEFF Research Database (Denmark)

    Henriksen, Marius; Mortensen, Sara Rosager; Aaboe, Jens

    2011-01-01

    Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following...... experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0....... Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension...

  12. Genetic Influences of OPRM1, OPRD1 and COMT on Morphine Analgesia in a Multi-Modal, Multi-Tissue Human Experimental Pain Model

    DEFF Research Database (Denmark)

    Nielsen, Lecia Møller; Christrup, Lona Louring; Sato, Hiroe

    2017-01-01

    Human studies on experimentally induced pain are of value to elucidate the genetic influence on morphine analgesia under controlled conditions. The aim of this study was to investigate if genetic variants of mu, kappa and delta opioid receptor genes (OPRM1, OPRK1 and OPRD1) and catechol......-O-methyltransferase gene (COMT) are associated with the morphine analgesia. The study was a randomised, double-blind, two-way, cross-over, single-dose study conducted in 40 healthy participants, where morphine was compared with placebo. Pain was induced by contact heat, muscle pressure, bone pressure, rectal stimulations......, results suggest that genetic variants in the COMT and OPRM1 irrespective of gender, and OPRD1 in males, may contribute to the variability in morphine analgesia in experimental pain models. This article is protected by copyright. All rights reserved....

  13. A comparison of the clinical and experimental characteristics of four acute surgical pain models: dental extraction, bunionectomy, joint replacement, and soft tissue surgery.

    Science.gov (United States)

    Singla, Neil K; Desjardins, Paul J; Chang, Phoebe D

    2014-03-01

    When a clinical trial of an analgesic produces a negative finding, it is important to consider the influence (if any) of experimental error on the validity of that result. Although efforts to identify and minimize experimental error in chronic pain investigations have begun in earnest, less work has been performed on the optimization of acute pain methodology. Of the acute surgical pain methodology articles that have been published over the last decade, almost all focus on either the dental or bunion model. Analgesics are typically evaluated in a variety of surgical models that eventually include hospital-based models (eg, joint replacement and soft tissue surgery). Every surgical procedure has unique clinical characteristics that must be considered to optimize study design and conduct. Much of the methodological knowledge garnered from bunion and dental studies is applicable to other surgical models, but some extrapolations are hazardous. The purposes of this review were (1) to qualitatively describe the clinical and experimental characteristics of the 4 classic surgical models: dental extraction, bunionectomy, joint replacement, and soft tissue surgery; and (2) to quantitatively compare the models by analyzing 3 factors: effect size, enrollment rate, and demographics. We found that the dental extraction and bunionectomy models had higher assay sensitivity than the joint replacement and soft tissue surgery models. It is probable that this finding is secondary to the superior experimental conditions under which the dental and bunion models are executed (utilization of few centers that have the ability to reduce surgical, anesthetic, and postoperative confounders). Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  14. Brain imaging of analgesic and antihyperalgesic effects of cyclooxygenase inhibition in an experimental human pain model: a functional MRI study.

    Science.gov (United States)

    Maihöfner, Christian; Ringler, Ralf; Herrndobler, Franz; Koppert, Wolfgang

    2007-09-01

    One of the most distressing symptoms of many neuropathic pain syndromes is the enhanced pain sensation to tactile or thermal stimulation (hyperalgesia). In the present study we used functional magnetic resonance imaging (fMRI) and explored brain activation patterns during acute impact pain and mechanical hyperalgesia in the human ultraviolet (UV)-B model. To investigate pharmacological modulation, we examined potential differential fMRI correlates of analgesic and antihyperalgesic effects of two intravenous cyclooxygenase inhibitors, i.e. parecoxib and acetylsalicylic acid (ASA). Fourteen healthy volunteers participated in this double-blinded, randomized and placebo-controlled crossover study. Tactile stimuli and mechanical impact hyperalgesia were tested at the site of a UV-B irradiation and acute mechanical pain was tested at a site distant from the irradiated skin. These measurements were conducted before and 30 min after a 5-min intravenous infusion of either saline (placebo), parecoxib 40 mg or ASA 1000 mg. Acute mechanical pain and mechanical hyperalgesia led to widespread activations of brain areas known to comprise the human pain matrix. Analgesic effects were found in primary (S1) and secondary (S2) somatosensory cortices, parietal association cortex (PA), insula, anterior parts of the cingulate cortex and prefrontal cortices. These brain areas were also modulated under antihyperalgesic conditions. However, we observed a greater drug-induced modulation of mainly PA and inferior frontal cortex during mechanical hyperalgesia; during acute mechanical pain there was a greater modulation of mainly bilateral S2. Therefore, the results of the present study suggest that there is a difference in the brain areas modulated by analgesia and antihyperalgesia.

  15. Altered experimental pain perception after cerebellar infarction.

    Science.gov (United States)

    Ruscheweyh, Ruth; Kühnel, Maria; Filippopulos, Filipp; Blum, Bernhard; Eggert, Thomas; Straube, Andreas

    2014-07-01

    Animal studies have suggested that the cerebellum, in addition to its motor functions, also has a role in pain processing and modulation, possibly because of its extensive connections with the prefrontal cortex and with brainstem regions involved in descending pain control. Consistently, human imaging studies have shown cerebellar activation in response to painful stimulation. However, it is presently not clear whether cerebellar lesions affect pain perception in humans. In the present study, we used experimental pain testing to compare acute pain perception and endogenous pain inhibition in 30 patients 1 to 11 years after cerebellar infarction and in 30 sex- and age-matched healthy control subjects. Compared to controls, patients exhibited a significantly increased pain perception in response to acute heat stimuli (44 °C-48 °C, average pain intensity rating for patients 3.4±2.8 and for controls 1.5±1.7 [on a numeric rating scale of 0-10], Ppain intensity rating: 0.0%±15.8% vs. -16.9%±36.3%, Ppain intensity rating: -1.0±1.1 vs. -1.8±1.3 [0-10], Pcontrols. In contrast, heat and pressure pain thresholds were not significantly different between groups. These results show that, after cerebellar infarction, patients perceive heat and repeated mechanical stimuli as more painful than do healthy control subjects and have deficient activation of endogenous pain inhibitory mechanisms (offset and placebo analgesia). This suggests that the cerebellum has a previously underestimated role in human pain perception and modulation. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  16. Time course of copeptin during a model of experimental pain and hyperalgesia: A randomised volunteer crossover trial.

    Science.gov (United States)

    Mauermann, Eckhard; Blum, Claudine A; Lurati Buse, Giovanna; Bandschapp, Oliver; Ruppen, Wilhelm

    2017-05-01

    A reliable biomarker for quantifying pain or hyperalgesia has yet to be found. A surrogate marker of arginine vasopressin, copeptin, is elevated in a number of states of physiological and psychological stress and may have a role in quantifying pain and/or hyperalgesia. To evaluate copeptin as a biomarker for pain or hyperalgesia developing after 120 min of sustained electrical stimulation. Secondary analysis of a randomised, double-blinded, crossover trial. Single, tertiary university hospital from September 2014 to January 2015. A total of 16 healthy, opioid-naïve white men with no confounding medication or history of pain. Copeptin and cortisol were measured five times during an established model of transdermal electrical stimulation designed to assess pain and hyperalgesia. The primary outcome was the change in copeptin concentration after 120 min of sustained electrical stimulation. Secondary outcomes were copeptin and cortisol concentrations after a subsequent period of rest and analyses of copeptin and cortisol concentrations were made in high-dose and low-dose fentanyl groups separately. Total copeptin concentrations were not significantly elevated after 120 min [9.15 pmol l (interquartile ranges (IQR), 3.45 to 35.45 pmol l); P = 0.150] compared with baseline [6.15 pmol l (IQR, 3.60 to 10.62 pmol l)]. In the high-dose fentanyl group, there was a significant increase in copeptin within individuals [P = 0.001; median, 37.9 pmol l (IQR, 8.1 to 62 pmol l)] after 120 min, and in the low-dose fentanyl group a significant decrease in copeptin concentrations within individuals [P = 0.006; median, 4.7 pmol l (IQR, 3.13 to 9.35 pmol l)]. No correlation between copeptin concentration and either the area under the pain curve or area under the hyperalgesia curve could be found, indicating that the observed differences may be due to other fentanyl-mediated effects. Copeptin concentrations do not appear to be associated

  17. Motor responses to experimental Achilles tendon pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Aaboe, Jens; Graven-Nielsen, Thomas

    2011-01-01

    different days separated by 1 week, three-dimensional ground reaction forces, ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded during one-legged full weight-bearing ankle plantar (concentric) and dorsal (eccentric) flexion exercises. Measurements were done...... before, during and after either experimental Achilles tendon pain or a non-painful control condition. Pain was induced by intratendinous injections of hypertonic saline with isotonic saline injections as control. Joint kinematics, ground reaction force frequency contents and average EMG amplitudes were...... calculated. Results Compared with the control condition experimental Achilles tendon pain reduced the EMG activity in agonistic, synergistic and antagonistic muscles, and increased the ground reaction force frequency content around 10 Hz, during both eccentric and concentric movement phases. Conclusions...

  18. Masseter motor unit recruitment is altered in experimental jaw muscle pain

    NARCIS (Netherlands)

    Minami, I.; Akhter, R.; Albersen, I.; Burger, C.; Whittle, T.; Lobbezoo, F.; Peck, C.C.; Murray, G.M.

    2013-01-01

    Some management strategies for chronic orofacial pain are influenced by models (e.g., Vicious Cycle Theory, Pain Adaptation Model) proposing either excitation or inhibition within a painful muscle. The aim of this study was to determine if experimental painful stimulation of the masseter muscle

  19. IL17 Mediates Pelvic Pain in Experimental Autoimmune Prostatitis (EAP.

    Directory of Open Access Journals (Sweden)

    Stephen F Murphy

    Full Text Available Chronic pelvic pain syndrome (CPPS is the most common form of prostatitis, accounting for 90-95% of all diagnoses. It is a complex multi-symptom syndrome with unknown etiology and limited effective treatments. Previous investigations highlight roles for inflammatory mediators in disease progression by correlating levels of cytokines and chemokines with patient reported symptom scores. It is hypothesized that alteration of adaptive immune mechanisms results in autoimmunity and subsequent development of pain. Mouse models of CPPS have been developed to delineate these immune mechanisms driving pain in humans. Using the experimental autoimmune prostatitis (EAP in C57BL/6 mice model of CPPS we examined the role of CD4+T-cell subsets in the development and maintenance of prostate pain, by tactile allodynia behavioral testing and flow cytometry. In tandem with increased CD4+IL17A+ T-cells upon EAP induction, prophylactic treatment with an anti-IL17 antibody one-day prior to EAP induction prevented the onset of pelvic pain. Therapeutic blockade of IL17 did not reverse pain symptoms indicating that IL17 is essential for development but not maintenance of chronic pain in EAP. Furthermore we identified a cytokine, IL7, to be associated with increased symptom severity in CPPS patients and is increased in patient prostatic secretions and the prostates of EAP mice. IL7 is fundamental to development of IL17 producing cells and plays a role in maturation of auto-reactive T-cells, it is also associated with autoimmune disorders including multiple sclerosis and type-1 diabetes. More recently a growing body of research has pointed to IL17's role in development of neuropathic and chronic pain. This report presents novel data on the role of CD4+IL17+ T-cells in development and maintenance of pain in EAP and CPPS.

  20. Experimental pain impairs recognition memory irrespective of pain predictability.

    Science.gov (United States)

    Forkmann, K; Schmidt, K; Schultz, H; Sommer, T; Bingel, U

    2016-07-01

    Pain is hardwired to signal threat and tissue damage and therefore automatically attracts attention to initiate withdrawal or defensive behaviour. This well-known interruptive function of pain interferes with cognitive functioning and is modulated by bottom-up and top-down variables. Here, we applied predictable or unpredictable painful heat stimuli simultaneously to the presentation of neutral images to investigate (I) whether the predictability of pain modulated its effect on the encoding of images (episodic memory) and (II) whether subjects remember that certain images have been previously presented with pain (source memory). Twenty-four healthy subjects performed a categorization task in which 80 images had to be categorized into living or non-living objects. We compared the processing and encoding of these images during cued and non-cued pain trials as well as cued and non-cued pain-free trials. Effects on recognition performance and source memory for pain were immediately tested using a surprise recognition task. Painful thermal stimulation impaired recognition accuracy (d', recollection, familiarity). This negative effect of pain was positively correlated with the individual expectation of pain interference and the attentional avoidance of pain-related words. However, the interruptive effect of pain was not modulated by the predictability of pain. Source memory for painful stimulation was at chance level, indicating that subjects did not explicitly remember that images had been paired with pain. Targeting negative expectations and a maladaptive attentional bias for pain-related material might help reducing frequently reported pain-induced cognitive impairments. © 2015 European Pain Federation - EFIC®

  1. Prediction of postoperative pain: a systematic review of predictive experimental pain studies

    DEFF Research Database (Denmark)

    Werner, Mads Utke; Mjöbo, Helena N; Nielsen, Per R

    2010-01-01

    preoperative responses to experimental pain stimuli and clinical postoperative pain and demonstrates that the preoperative pain tests may predict 4-54% of the variance in postoperative pain experience depending on the stimulation methods and the test paradigm used. The predictive strength is much higher than...... previously reported for single factor analyses of demographics and psychologic factors. In addition, some of these studies indicate that an increase in preoperative pain sensitivity is associated with a high probability of development of sustained postsurgical pain....

  2. Time discounting and pain anticipation. Experimental evidence

    Directory of Open Access Journals (Sweden)

    Brañas Garza, Pablo

    2012-03-01

    Full Text Available This paper deals with pain anticipation experienced before medical procedures. our experimental results show that individuals with lower time discount factors are more prone to suffer pain in advance. We provide a framework to rationalize the connection between pain anticipation and impatience. in this set up, more impatient subjects, who only value very near events, mainly take into account the present negative effects of medical procedures (the costs, whereas more patient individuals have a net positive valuation of medical events, given that they are able to value both the cost incurred now and all the benefits to be accrued in the future.

    Este artículo trata de la anticipación del dolor experimentada antes de los procedimientos médicos. nuestros resultados experimentales muestran que los individuos con factor de descuento temporal más bajo son más proclives a sufrir dolor por adelantado. el artículo proporciona un marco en el que racionalizar la relación existente entre impaciencia y anticipación del dolor. en este marco, los sujetos más impacientes, que evalúan sólo los eventos muy próximos en el tiempo, focalizan su atención principalmente en los efectos negativos de los procedimientos médicos (sólo los costes, mientras que los individuos más pacientes tienen una valoración neta positiva de los actos médicos puesto que valoran tanto el coste en el que se incurre en el presente como los beneficios que se obtendrán en el futuro.

  3. Experimental Pain Responses Support Peripheral and Central Sensitization in Patients with Unilateral Shoulder Pain

    Science.gov (United States)

    Coronado, Rogelio A.; Simon, Corey B.; Valencia, Carolina; George, Steven Z.

    2013-01-01

    Objective The aims of this study were to 1) examine the pattern of experimental pain responses in the affected and non-affected extremities in patients with shoulder pain and 2) explore the intra-individual association between sensitization states derived from experimental pain testing. Methods Experimental pain responses from 58 patients with shoulder pain (17 females, ages 18 to 52) were compared to those from 56 age- and sex-matched healthy volunteers (16 females, ages 21 to 58). Experimental pain responses included pressure pain threshold (PPT), thermal pain threshold and tolerance, and suprathreshold heat pain response (SHPR). Comparisons were made between the affected and non-affected extremity of clinical participants and the average response of extremities in healthy participants. Peripheral and central sensitization indexes were computed for clinical participants using standardized scores and percentile cut-offs based on the data from the healthy control sample. Experimental pain responses in clinical participants observed beyond the 25th and 75th percentile of healthy control sample responses were used for investigation of intra-individual association of sensitization states. Results PPT on the affected side acromion and masseter of clinical participants were diminished compared to their non-affected side (p shoulder pain present with variable patterns of peripheral and central sensitization. Conclusions Collectively, experimental pain responses supported peripheral and central sensitization in response to pressure and thermal stimuli. No clear association was made between individuals exhibiting peripheral or central sensitization and suggests heterogeneity in pain processing in this clinical population. PMID:23619203

  4. A novel modelling and experimental technique to predict and measure tissue temperature during CO2 laser stimuli for human pain studies.

    Science.gov (United States)

    Al-Saadi, Mohammed Hamed; Nadeau, V; Dickinson, M R

    2006-07-01

    Laser nerve stimulation is now accepted as one of the preferred methods for applying painful stimuli to human skin during pain studies. One of the main concerns, however, is thermal damage to the skin. We present recent work based on using a CO2 laser with a remote infrared (IR) temperature sensor as a feedback system. A model for predicting the subcutaneous skin temperature derived from the signal from the IR detector allows us to accurately predict the laser parameters, thus maintaining an optimum pain stimulus whilst avoiding dangerous temperature levels, which could result in thermal damage. Another aim is to relate the modelling of the CO2 fibre laser interaction to the pain response and compare these results with practical measurements of the pain threshold for various stimulus parameters. The system will also allow us to maintain a constant skin temperature during the stimulus. Another aim of the experiments underway is to review the psychophysics for pain in human subjects, permitting an investigation of the relationship between temperature and perceived pain.

  5. Bilateral experimental neck pain reorganize axioscapular muscle coordination and pain sensitivity.

    Science.gov (United States)

    Christensen, S W; Hirata, R P; Graven-Nielsen, T

    2017-04-01

    Neck pain is a large clinical problem where reorganized trunk and axioscapular muscle activities have been hypothesised contributing to pain persistence and pain hypersensitivity. This study investigated the effects of bilateral experimental neck pain on trunk and axioscapular muscle function and pain sensitivity. In 25 healthy volunteers, bilateral experimental neck pain was induced in the splenius capitis muscles by hypertonic saline injections. Isotonic saline was used as control. In sitting, subjects performed slow, fast and slow-resisted unilateral arm movements before, during and after injections. Electromyography (EMG) was recorded from eight shoulder and trunk muscles bilaterally. Pressure pain thresholds (PPTs) were assessed bilaterally at the neck, head and arm. Data were normalized to the before-measures. Compared with control and post measurements, experimental neck pain caused (1) decreased EMG activity of the ipsilateral upper trapezius muscles during all but slow-resisted down movements (p < 0.001), and (2) increased EMG activity in the ipsilateral erector spinae muscle during slow and fast movements (p < 0.02), and in the contralateral erector spinae muscle during all but fast up and slow-resisted down movements (p < 0.007). The PPTs in the painful condition increased at the head and arm compared with post measurements and the control condition (p < 0.001). In the post-pain condition, the neck PPT was decreased compared with the control condition (p < 0.001). Acute bilateral neck pain reorganized axioscapular and trunk muscle activity together with local hyperalgesia and widespread hypoalgesia indicating that acute neck pain immediately affects trunk and axioscapular function which may affect both assessment and treatment. Bilateral clinical neck pain alters axioscapular muscle coordination but only effects of unilateral experimental neck pain has been investigated. Bilateral experimental neck pain causes task-dependent reorganized

  6. Are preoperative experimental pain assessments correlated with clinical pain outcomes after surgery?

    DEFF Research Database (Denmark)

    Sangesland, Anders; Støren, Carl; Vaegter, Henrik B.

    2017-01-01

    was to evaluate whether assessment of experimental pain processing including measures of central pain mechanisms prior to surgery was associated with pain intensity after surgery. Methods Systematic database searches in PubMed and EMBASE with the following search components: QST, association, and postoperative......Background Pain after surgery is not uncommon with 30% of patients reporting moderate to severe postoperative pain. Early identification of patients prone to postoperative pain may be a step forward towards individualized pain medicine providing a basis for improved clinical management through...... treatment strategies targeting relevant pain mechanisms in each patient. Assessment of pain processing by quantitative sensory testing (QST) prior to surgery has been proposed as a method to identify patients at risk for postoperative pain, although results have been conflicting. Since the last systematic...

  7. Observational learning and pain-related fear: an experimental study with colored cold pressor tasks.

    Science.gov (United States)

    Helsen, Kim; Goubert, Liesbet; Peters, Madelon L; Vlaeyen, Johan W S

    2011-12-01

    The primary aim of the current study was to experimentally test whether pain-related fear can be acquired through observational learning, whether extinction occurs after actual exposure to the aversive stimulus, and whether pain-related fear was associated with increased pain ratings. During an observation phase, female volunteers watched a video showing models performing cold pressor tasks (CPT), of which the color served as a conditioned stimulus (CS). In a differential fear conditioning paradigm, each of 2 colors were either paired with models' painful (CS+) or neutral (CS-) facial expressions. Exposure consisted of participants performing CPTs of both colors (10°C). Self-reported fear of pain and expected pain ratings were obtained after the observation period, while actual pain and avoidance measures were obtained during and after exposure. Results show that after observing another person performing the CPT associated with the painful faces, subjects report more fear of pain and expect more intense and unpleasant pain as compared with the CPT associated with the neutral faces. This effect of observational learning on pain-related fear persisted until after exposure. During and after exposure no stimulus-type effect for pain ratings was found. This study provides preliminary evidence for observational learning of pain-related fear in humans. Fear of pain can be more disabling than pain itself, and is a risk factor for chronic pain. Knowledge about the acquisition of pain-related fear may help to develop novel pain management programs. This study is one of the first to demonstrate the effects of observational learning on pain-related fear. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  8. Meta-analysis on brain representation of experimental dental pain.

    Science.gov (United States)

    Lin, C-S; Niddam, D M; Hsu, M-L

    2014-02-01

    Functional magnetic resonance imaging (fMRI) has been widely used for investigating the brain representation associated with dental pain evoked by pulpal electrical stimulation. However, because of the heterogeneity of experimental designs and the small sample size of individual studies, the common brain representation regarding dental pain has remained elusive. We used imaging meta-analysis to investigate six dental pain-related fMRI studies (n = 87) and tested 3 hypotheses: (1) Dental pain is associated with the 'core' pain-related network; (2) pain-related brain activation is somatotopically organized in the somatosensory cortex; and (3) dental pain is associated with the cognitive-affective network related to pain. Qualitative and quantitative meta-analyses revealed: (1) common activation of the core pain-related network, including the somatosensory cortex, the insula, and the cingulate cortex; (2) inconsistency in somatotopically organized activation of the primary somatosensory cortex; and (3) common activation in the dorsolateral prefrontal cortex, suggesting a role of re-appraisal and coping in the experience of dental pain. In conclusion, fMRI combined with pulpal stimulation can effectively evoke activity in the pain-related network. The dental pain-related brain representation disclosed the mechanisms of how sensory and cognitive-affective factors shape dental pain, which will help in the development of more effective customized methods for central pain control.

  9. The role of experimentally-induced subacromial pain on shoulder strength and throwing accuracy.

    Science.gov (United States)

    Wassinger, Craig A; Sole, Gisela; Osborne, Hamish

    2012-10-01

    Shoulder injuries often comprise two separate yet related components, structural tissue damage and pain. The role of each of these components on shoulder function is difficult to ascertain. Experimental pain models allow the assessment of consequences of localized pain when applied to healthy individuals. By understanding the role of pain on shoulder function, clinicians will be able to more efficiently assess and treat shoulder injuries. The objective of the study was to evaluate the role of experimentally-induced sub-acromial pain on shoulder isokinetic rotational strength and throwing accuracy. This was a block counterbalanced, crossover, repeated measures study design utilizing 20 individuals without self-reported shoulder or cervical pathology. Shoulder function was measured with and without experimental pain injection (2 mL of 5% hypertonic saline) in the sub-acromial space. Functional tasks consisted of shoulder rotational strength utilizing isokinetic testing and throwing accuracy via the functional throwing performance index. The hypertonic saline induced moderate pain levels in all participants (4.3-5.1/10). Normalized shoulder internal (t = 3.76, p = 0.001) and external (t = 3.12, p = 0.006) rotation strength were both diminished in the painful condition compared to the pain free condition. Throwing accuracy was also reduced while the participants experienced pain (t = 3.99, p = 0.001). Moderate levels of experimental shoulder pain were sufficient to negatively influence shoulder strength and throwing accuracy in participants without shoulder pathology. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Prediction of postoperative pain: a systematic review of predictive experimental pain studies

    DEFF Research Database (Denmark)

    Werner, Mads Utke; Mjöbo, Helena N; Nielsen, Per R

    2010-01-01

    Quantitative testing of a patient's basal pain perception before surgery has the potential to be of clinical value if it can accurately predict the magnitude of pain and requirement of analgesics after surgery. This review includes 14 studies that have investigated the correlation between...... preoperative responses to experimental pain stimuli and clinical postoperative pain and demonstrates that the preoperative pain tests may predict 4-54% of the variance in postoperative pain experience depending on the stimulation methods and the test paradigm used. The predictive strength is much higher than...

  11. Experimental Sleep Restriction Facilitates Pain and Electrically Induced Cortical Responses.

    Science.gov (United States)

    Matre, Dagfinn; Hu, Li; Viken, Leif A; Hjelle, Ingri B; Wigemyr, Monica; Knardahl, Stein; Sand, Trond; Nilsen, Kristian Bernhard

    2015-10-01

    Sleep restriction (SR) has been hypothesized to sensitize the pain system. The current study determined whether experimental sleep restriction had an effect on experimentally induced pain and pain-elicited electroencephalographic (EEG) responses. A paired crossover study. Pain testing was performed after 2 nights of 50% SR and after 2 nights with habitual sleep (HS). Laboratory experiment at research center. Self-reported healthy volunteers (n = 21, age range: 18-31 y). Brief high-density electrical stimuli to the forearm skin produced pinprick-like pain. Subjective pain ratings increased after SR, but only in response to the highest stimulus intensity (P = 0.018). SR increased the magnitude of the pain-elicited EEG response analyzed in the time-frequency domain (P = 0.021). Habituation across blocks did not differ between HS and SR. Event-related desynchronization (ERD) was reduced after SR (P = 0.039). Pressure pain threshold of the trapezius muscle region also decreased after SR (P = 0.017). Sleep restriction (SR) increased the sensitivity to pressure pain and to electrically induced pain of moderate, but not low, intensity. The increased electrical pain could not be explained by a difference in habituation. Increased response magnitude is possibly related to reduced processing within the somatosensory cortex after partial SR. © 2015 Associated Professional Sleep Societies, LLC.

  12. Efficacy of Sensory Transcutaneous Electrical Nerve Stimulation on Perceived Pain and Gait Patterns in Individuals With Experimental Knee Pain.

    Science.gov (United States)

    Son, S Jun; Kim, Hyunsoo; Seeley, Matthew K; Hopkins, J Ty

    2017-01-01

    To examine the effect of experimental knee pain on perceived knee pain and gait patterns and to examine the efficacy of transcutaneous electrical nerve stimulation (TENS) on perceived knee pain and pain-induced knee gait mechanics. Crossover trial. Biomechanics laboratory. Recreationally active, individuals without musculoskeletal pain aged 18 to 35 years (N=30). Thirty able-bodied individuals were assigned to either a TENS (n=15) or a placebo (n=15) group. All participants completed 3 experimental sessions in a counterbalanced order separated by 2 days: (1) hypertonic saline infusion (5% NaCl); (2) isotonic saline infusion (0.9% NaCl); and (3) control. Each group received sensory electrical stimulation or placebo treatment for 20 minutes, respectively. Perceived pain was collected every 2 minutes using a 10-cm visual analog scale (VAS) for 50 minutes and analyzed using a mixed model analysis of covariance with repeated measures. Gait analyses were performed at baseline, infusion, and treatment. Sagittal and frontal knee angles and internal net joint torque across the entire stance were analyzed using a functional data analysis approach. Hypertonic saline infusion increased perceived pain (4/10cm on a VAS; Pgait abnormalities as compared with placebo treatment (Pgait patterns in a way that indicates potential quadriceps weakness. However, TENS treatment effectively reduces perceived pain and restores pain-induced gait abnormalities in sagittal knee mechanics. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  13. Interventional pain medicine: retreat from the biopsychosocial model of pain.

    Science.gov (United States)

    Roth, Randy S; Geisser, Michael E; Williams, David A

    2012-03-01

    The field of pain medicine has shifted from multidisciplinary rehabilitation to procedure-focused interventional pain medicine (IPM). Considerable controversy exists regarding the efficacy of IPM and its more narrow focus on nociception as an exclusive target of pain treatment. This topical review aims to examine pain research and treatment outcome studies that support a biopsychosocial model of pain, and to critique the clinical practice of IPM given its departure from the premises of a biopsychosocial model. A modern definition of pain and findings from clinical and basic science studies indicate that pain-related psychological factors are integral to pain perception. The clinical viability of IPM is challenged based upon its biomedical view of peripheral nociception as a primary source of pain and the potential of this viewpoint to foster maladaptive pain attributions and discourage the use of pain coping strategies among chronic pain patients. IPM should adopt a biopsychosocial perspective on pain and operate within a framework of multidisciplinary pain rehabilitation to improve its effectiveness.

  14. The influence of experimentally induced pain on shoulder muscle activity.

    Science.gov (United States)

    Diederichsen, Louise Pyndt; Winther, Annika; Dyhre-Poulsen, Poul; Krogsgaard, Michael R; Nørregaard, Jesper

    2009-04-01

    Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0 degrees -105 degrees) at a speed of approximately 120 degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows that acute pain both subacromially and in the supraspinatus muscle modulates coordination of the shoulder muscles during voluntary movements. During painful conditions, an increased activity was detected in the antagonist (latissimus), which support the idea that localized pain affects muscle activation in a way that protects the painful structure. Further, the changes in muscle activity following subacromial pain induction tend to expand the subacromial space and thereby decrease the load

  15. Do patients with chronic pain show autonomic arousal when confronted with feared movements? An experimental investigation of the fear-avoidance model.

    Science.gov (United States)

    Glombiewski, Julia Anna; Riecke, Jenny; Holzapfel, Sebastian; Rief, Winfried; König, Stephan; Lachnit, Harald; Seifart, Ulf

    2015-03-01

    The relevance of a phobia-based conceptualization of fear for individuals with chronic pain has been much debated in the literature. This study investigated whether patients with highly fearful chronic low back pain show distinct physiological reaction patterns compared with less fearful patients when anticipating aversive back pain-related movements. We used an idiosyncratic fear induction paradigm and collected 2 different measures of autonomic nervous system activation and muscle tension in the lower back. We identified 2 distinct psychophysiological response patterns. One pattern was characterized by a moderate increase in skin conductance, interbeat interval (IBI) increase, and muscle tension increase in the lower back. This response was interpreted as an attention reaction to a moderately stressful event. The other pattern, found in 58% of the participants, was characterized by a higher skin conductance response, IBI decrease, and muscle tension increase in the lower back. According to Bradley and Lang defense cascade model, this response is typical of a fear reaction. Participants showing the psychophysiological pattern typical of fear also had elevated scores on some self-report measures of components of the fear-avoidance model, relative to participants showing the reaction pattern characteristic of attention. This study is the first to provide psychophysiological evidence for the fear-avoidance model of chronic pain.

  16. Adaptations in the gait pattern with experimental hamstring pain

    DEFF Research Database (Denmark)

    Henriksen, M; Mortensen, Sara Rosager; Aaboe, J

    2011-01-01

    Pain changes movement but most studies have focused on basic physiological adaptations during non-functional movement tasks. The existing studies on how pain affects lower extremity gross movement biomechanics have primarily involved movements in which the quadriceps is the primary muscle...... and little attention has been given to how pain in other muscles affects functional movement. The purpose of this study was to investigate the changes in the gait patterns of healthy subjects that occur during experimental muscle pain in the biceps femoris. In a cross-over study design, 14 healthy volunteers......, knee flexor and lateral rotator moments. No changes in lower extremity kinematics and EMG activity in any of the recorded muscles were observed. It is concluded that experimental muscle pain in the biceps femoris leads to changes in the gait pattern in agreement with unloading of the painful muscle...

  17. Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats.

    Science.gov (United States)

    Long, Hu; Liao, Lina; Gao, Meiya; Ma, Wenqiang; Zhou, Yang; Jian, Fan; Wang, Yan; Lai, Wenli

    2015-08-01

    Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Manipulation of pain catastrophizing: An experimental study of healthy participants

    Directory of Open Access Journals (Sweden)

    Joel E Bialosky

    2008-11-01

    Full Text Available Joel E Bialosky1*, Adam T Hirsh2,3, Michael E Robinson2,3, Steven Z George1,3*1Department of Physical Therapy; 2Department of Clinical and Health Psychology; 3Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida, USAAbstract: Pain catastrophizing is associated with the pain experience; however, causation has not been established. Studies which specifically manipulate catastrophizing are necessary to establish causation. The present study enrolled 100 healthy individuals. Participants were randomly assigned to repeat a positive, neutral, or one of three catastrophizing statements during a cold pressor task (CPT. Outcome measures of pain tolerance and pain intensity were recorded. No change was noted in catastrophizing immediately following the CPT (F(1,84 = 0.10, p = 0.75, partial η2 < 0.01 independent of group assignment (F(4,84 = 0.78, p = 0.54, partial η2 = 0.04. Pain tolerance (F(4 = 0.67, p = 0.62, partial η2 = 0.03 and pain intensity (F(4 = 0.73, p = 0.58, partial η2 = 0.03 did not differ by group. This study suggests catastrophizing may be difficult to manipulate through experimental pain procedures and repetition of specific catastrophizing statements was not sufficient to change levels of catastrophizing. Additionally, pain tolerance and pain intensity did not differ by group assignment. This study has implications for future studies attempting to experimentally manipulate pain catastrophizing.Keywords: pain, catastrophizing, experimental, cold pressor task, pain catastrophizing scale

  19. Effect of experimental chewing on masticatory muscle pain onset

    Directory of Open Access Journals (Sweden)

    Paulo César Rodrigues Conti

    2011-02-01

    Full Text Available OBJECTIVES: To evaluate the effect of a chewing exercise on pain intensity and pressure-pain threshold in patients with myofascial pain. METHODS: Twenty-nine consecutive women diagnosed with myofascial pain (MFP according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. RESULTS: Patients with myofascial pain reported increase (76% and no change (24% on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. CONCLUSION: The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls.

  20. Experimental Sleep Restriction Facilitates Pain and Electrically Induced Cortical Responses

    Science.gov (United States)

    Matre, Dagfinn; Hu, Li; Viken, Leif A.; Hjelle, Ingri B.; Wigemyr, Monica; Knardahl, Stein; Sand, Trond; Nilsen, Kristian Bernhard

    2015-01-01

    Study Objectives: Sleep restriction (SR) has been hypothesized to sensitize the pain system. The current study determined whether experimental sleep restriction had an effect on experimentally induced pain and pain-elicited electroencephalographic (EEG) responses. Design: A paired crossover study. Intervention: Pain testing was performed after 2 nights of 50% SR and after 2 nights with habitual sleep (HS). Setting: Laboratory experiment at research center. Participants: Self-reported healthy volunteers (n = 21, age range: 18–31 y). Measurements and Results: Brief high-density electrical stimuli to the forearm skin produced pinprick-like pain. Subjective pain ratings increased after SR, but only in response to the highest stimulus intensity (P = 0.018). SR increased the magnitude of the pain-elicited EEG response analyzed in the time-frequency domain (P = 0.021). Habituation across blocks did not differ between HS and SR. Event-related desynchronization (ERD) was reduced after SR (P = 0.039). Pressure pain threshold of the trapezius muscle region also decreased after SR (P = 0.017). Conclusion: Sleep restriction (SR) increased the sensitivity to pressure pain and to electrically induced pain of moderate, but not low, intensity. The increased electrical pain could not be explained by a difference in habituation. Increased response magnitude is possibly related to reduced processing within the somatosensory cortex after partial SR. Citation: Matre D, Hu L, Viken LA, Hjelle IB, Wigemyr M, Knardahl S, Sand T, Nilsen KB. Experimental sleep restriction facilitates pain and electrically induced cortical responses. SLEEP 2015;38(10):1607–1617. PMID:26194577

  1. The effect of experimentally-induced subacromial pain on proprioception.

    Science.gov (United States)

    Sole, Gisela; Osborne, Hamish; Wassinger, Craig

    2015-02-01

    Shoulder injuries may be associated with proprioceptive deficits, however, it is unknown whether these changes are due to the experience of pain, tissue damage, or a combination of these. The aim of this study was to investigate the effect of experimentally-induced sub-acromial pain on proprioceptive variables. Sub-acromial pain was induced via hypertonic saline injection in 20 healthy participants. Passive joint replication (PJR) and threshold to detection of movement direction (TTDMD) were assessed with a Biodex System 3 Pro isokinetic dynamometer for baseline control, experimental pain and recovery control conditions with a starting position of 60° shoulder abduction. The target angle for PJR was 60° external rotation, starting from 40°. TTDMD was tested from a position of 20° external rotation. Repeated measures ANOVAs were used to determine differences between PJR absolute and variable errors and TTDMD for the control and experimental conditions. Pain was elicited with a median 7 on the Numeric Pain Rating Scale. TTDMD was significantly decreased for the experimental pain condition compared to baseline and recovery conditions (≈30%, P = 0.003). No significant differences were found for absolute (P = 0.152) and variable (P = 0.514) error for PJR. Movement sense was enhanced for the experimental sub-acromial pain condition, which may reflect protective effects of the central nervous system in response to the pain. Where decreased passive proprioception is observed in shoulders with injuries, these may be due to a combination of peripheral tissue injury and neural adaptations that differ from those due to acute pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Effect of somatosensory amplification and trait anxiety on experimentally induced orthodontic pain.

    Science.gov (United States)

    Cioffi, Iacopo; Michelotti, Ambrosina; Perrotta, Stefania; Chiodini, Paolo; Ohrbach, Richard

    2016-04-01

    The perception of pain varies considerably across individuals and is affected by psychological traits. This study aimed to investigate the combined effects of somatosensory amplification and trait anxiety on orthodontic pain. Five-hundred and five adults completed the State Trait Anxiety Inventory (STAI) and the Somatosensory Amplification Scale (SSAS). Individuals with combined STAI and SSAS scores below the 20th percentile (LASA group: five men and 12 women; mean age ± SD = 22.4 ± 1.3 yr) or above the 80th percentile (HASA group: 13 men and seven women; mean age ± SD = 23.7 ± 1.0 yr) were selected and filled in the Oral Behaviors Checklist (OBC). Orthodontic separators were placed for 5 d in order to induce experimental pain. Visual analog scales (VAS) were administered to collect ratings for occlusal discomfort, pain, and perceived stress. Pressure pain thresholds (PPT) were measured. A mixed regression model was used to evaluate pain and discomfort ratings over the 5-d duration of the study. At baseline, the LASA group had statistically significantly higher PPT values for the masseter muscle than did the HASA group. During the experimental procedure, the HASA group had statistically significantly higher discomfort and pain. A significant difference in pain ratings during the 5 d of the study was found for subjects in the HASA group. Higher OBC values were statistically significantly positively associated with pain. Somatosensory amplification and trait anxiety substantially affect experimentally induced orthodontic pain. © 2016 Eur J Oral Sci.

  3. The effect of a combination of gabapentin and donepezil in an experimental pain model in healthy volunteers: Results of a randomized controlled trial.

    Science.gov (United States)

    Boyle, Yvonne; Fernando, Disala; Kurz, Hazel; Miller, Sam R; Zucchetto, Mauro; Storey, James

    2014-12-01

    This double-blind, placebo-controlled, 3-period cross-over, 4-treatment option, incomplete block study (ClinicalTrials.gov number NCT01485185), with an adaptive design for sample size re-estimation, was designed to evaluate gabapentin plus donepezil in an established experimental model of electrical hyperalgesia. Thirty healthy male subjects aged 18-55 years were randomized to receive gabapentin 900 mg or gabapentin 900 mg+donepezil 5mg for 2 of the 3 treatment periods, with 50% of subjects randomized to receive placebo (negative control) and 50% to gabapentin 1800 mg (positive control) for the remaining period. Each treatment period was 14 days. Gabapentin or corresponding placebo was administered on Day 13 and the morning of Day 14. Donepezil or corresponding placebo was administered nocturnally from Day 1-13 and the morning of Day 14. Co-primary endpoints were the area of pinprick hyperalgesia (260 mN von Frey filament) and allodynia (stroking by cotton bud) evoked by electrical hyperalgesia on Day 14. Gabapentin 1800 mg (n=14) significantly reduced the area of allodynia vs placebo (n=14; -12.83 cm(2); 95% confidence interval [CI] -23.14 to -2.53; P=0.015) with supportive results for hyperalgesia (-14.04 cm(2); 95% CI -28.49-0.41; P=0.057), validating the electrical hyperalgesia model. Gabapentin+donepezil (n=30) significantly reduced the area of hyperalgesia vs gabapentin 900 mg (n=30; -11.73 cm(2); 95% CI -21.04 to -2.42; P=0.014), with supportive results for allodynia (-6.62 cm(2); 95% CI -13.29-0.04; P=0.052). The adverse event profile for gabapentin+donepezil was similar to the same dose of gabapentin. Data are supportive of further clinical investigation of a gabapentin-and-donepezil combination in patients with an inadequate response to gabapentin. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  4. Gender bias in the observation of experimental pain.

    Science.gov (United States)

    Robinson, Michael E; Wise, Emily A

    2003-07-01

    The aim of this study was to examine how men and women observe experimentally induced pain in male and female participants and to specifically determine the accuracy of observed pain ratings, the possible interactions between the sex of the viewer and the sex of the individual being observed, and the influence of gender role expectations on observed pain ratings. The sample comprised 29 participants (15 females). They each completed a battery of psychological questionnaires and viewed a presentation of 10 randomly ordered video clips. Each presentation consisted of 10 video clips, lasting 30s, of a participant (five males and five females) in the cold pressor task. The participants viewing the videos were asked to provide several ratings, including observed pain intensity and gender role related characteristics of the individual in the video. In terms of sex of the video participant, results indicated that viewers rated male videos as having less pain than female videos although the effect was small. Regarding sex of the viewer, results indicated that for both male and female videos, female viewers rated observed pain intensity significantly higher than did male viewers. In terms of accuracy, results indicated that on average, female video participants' pain was underestimated by 14 points, while male videos participants' pain was underestimated by 22 points (on a 0-100-point scale). Pain intensity ratings and pain tolerance from the participants in the videos did not differ significantly with respect to sex, though women had shorter tolerance times and higher pain ratings than men. Hierarchical regression analyses indicated that expectations of gender related 'endurance of pain' significantly predicted ratings of both male and female videos. When endurance expectations were controlled, sex of the viewer no longer significantly predicted observed pain ratings. The 'willingness to report pain' variable was not a significant predictor of observed pain ratings. Our

  5. The influence of working memory capacity on experimental heat pain.

    Science.gov (United States)

    Nakae, Aya; Endo, Kaori; Adachi, Tomonori; Ikeda, Takashi; Hagihira, Satoshi; Mashimo, Takashi; Osaka, Mariko

    2013-10-01

    Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception. In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. A computational model unifies apparently contradictory findings concerning phantom pain

    Science.gov (United States)

    Boström, Kim J.; de Lussanet, Marc H. E.; Weiss, Thomas; Puta, Christian; Wagner, Heiko

    2014-06-01

    Amputation often leads to painful phantom sensations, whose pathogenesis is still unclear. Supported by experimental findings, an explanatory model has been proposed that identifies maladaptive reorganization of the primary somatosensory cortex (S1) as a cause of phantom pain. However, it was recently found that BOLD activity during voluntary movements of the phantom positively correlates with phantom pain rating, giving rise to a model of persistent representation. In the present study, we develop a physiologically realistic, computational model to resolve the conflicting findings. Simulations yielded that both the amount of reorganization and the level of cortical activity during phantom movements were enhanced in a scenario with strong phantom pain as compared to a scenario with weak phantom pain. These results suggest that phantom pain, maladaptive reorganization, and persistent representation may all be caused by the same underlying mechanism, which is driven by an abnormally enhanced spontaneous activity of deafferented nociceptive channels.

  7. Opioid and noradrenergic contributions of tapentadol in experimental neuropathic pain.

    Science.gov (United States)

    Meske, Diana S; Xie, Jennifer Y; Oyarzo, Janice; Badghisi, Hamid; Ossipov, Michael H; Porreca, Frank

    2014-03-06

    Tapentadol is a dual action molecule with mu opioid agonist and norepinephrine (NE) reuptake blocking activity that has recently been introduced for the treatment of moderate to severe pain. The effects of intraperitoneal (i.p.) morphine (10mg/kg), tapentadol (10 or 30 mg/kg) or duloxetine (30 mg/kg), a norepinephrine/serotonin (NE/5HT) reuptake inhibitor, were evaluated in male, Sprague-Dawley rats with spinal nerve ligation (SNL) or sham surgery. Additionally, the effects of these drugs on spinal cerebrospinal fluid (CSF) NE levels were quantified. Response thresholds to von Frey filament stimulation decreased significantly from baseline in SNL, but not sham, operated rats. Duloxetine, tapentadol and morphine produced significant and time-related reversal of tactile hypersensitivity. Duloxetine significantly increased spinal CSF NE levels in both sham and SNL rats and no significant differences were observed in these groups. Tapentadol (10 mg/kg) produced a significant increase in spinal NE levels in SNL, but not in sham, rats. At the higher dose (30 mg/kg), tapentadol produced a significant increase in spinal CSF NE levels in both SNL and sham groups; however, spinal NE levels were elevated for an extended period in the SNL rats. This could be detected 30 min following tapentadol (30 mg/kg) in both sham and SNL groups. Surprisingly, while the dose of morphine studied reversed tactile hypersensitivity in nerve-injured rats, CSF NE levels were significantly reduced in both sham- and SNL rats. The data suggest that tapentadol elicits enhanced elevation in spinal NE levels in a model of experimental neuropathic pain offering a mechanistic correlate to observed clinical efficacy in this pain state. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Pain by Association? Experimental Modulation of Human Pain Thresholds Using Classical Conditioning.

    Science.gov (United States)

    Madden, Victoria J; Bellan, Valeria; Russek, Leslie N; Camfferman, Danny; Vlaeyen, Johan W S; Moseley, G Lorimer

    2016-10-01

    A classical conditioning framework is often used for clinical reasoning about pain that persists after tissue healing. However, experimental studies demonstrating classically conditioned pain in humans are lacking. The current study tested whether non-nociceptive somatosensory stimuli can come to modulate pain thresholds after being paired with painful nociceptive stimuli in healthy humans. We used a differential simultaneous conditioning paradigm in which one nonpainful vibrotactile conditioned stimulus (CS(+)) was simultaneously paired with an unconditioned painful laser stimulus, and another vibrotactile stimulus (CS(-)) was paired with a nonpainful laser stimulus. After acquisition, at-pain-threshold laser stimuli were delivered simultaneously with a CS(+) or CS(-) vibrotactile stimulus. The primary outcome was the percentage of at-threshold laser stimuli that were reported as painful. The results were as expected: after conditioning, at-threshold laser trials paired with the CS(+) were reported as painful more often, as more intense, and as more unpleasant than those paired with the CS(-). This study provides new evidence that pain thresholds can be modulated via classical conditioning, even when the stimulus used to test the threshold cannot be anticipated. As such, it lays a critical foundation for further investigations of classical conditioning as a possible driver of persistent pain. This study provides new evidence that human pain thresholds can be influenced by non-nociceptive somatosensory stimuli, via a classical conditioning effect. As such, it lays a critical foundation for further investigations of classical conditioning as a possible driver of persistent pain. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  9. Uso do laser, 670 nm, no quadro álgico de ratos submetidos à modelo experimental de ciatalgia Use of laser, 670 nm, in painful episodes of rats submitted to experimental model of sciatica

    Directory of Open Access Journals (Sweden)

    Núbia Broetto Cunha

    2008-04-01

    Full Text Available A ciatalgia deve-se a compressão do nervo isquiático em algum ponto de seu trajeto, e seu tratamento consiste em solucionar a causa da compressão nervosa, seja por tratamento cirúrgico ou conservador. Alguns recursos fisioterapêuticos atuam basicamente na redução dos sintomas ocasionados por este distúrbio. O objetivo deste estudo foi verificar a eficácia do laser 670 nm, em duas diferentes densidades de energia, na redução do quadro álgico, em ratos submetidos a modelo experimental de ciatalgia. Foram utilizados 18 ratos, divididos em 3 grupos: G1 (n=6 submetidos à ciatalgia e simulado o tratamento (grupo placebo, G2 (n=6 submetido à ciatalgia e tratados com laser 2 J/cm², G3 (n=6 submetidos à ciatalgia e irradiados com laser 4 J/cm². O nervo isquiático do membro posterior direito dos animais foi exposto e compressão com fio catgut em 4 pontos ao redor do nervo foi realizada. No 3° dia pós-operatório, iniciou-se o tratamento com laser na região do procedimento cirúrgico do membro posterior direito durante 10 dias consecutivos. Verificou-se por meio da marcha, o tempo em que o membro permanecia no ar nos períodos: anterior à ciatalgia, pré e pós-tratamento. Os resultados demonstraram que o laser não foi eficaz na redução do quadro álgico, porém com 4 J/cm² houve efeito positivo, sem restabelecimento completo da funcionalidade.Sciatica is caused by the sciatic nerve compression in some point of its course, and its treatment consists of solving the nervous compression cause, either by surgical or conservative treatment. Some physiotherapeutic resources act basically in the reduction of the symptoms caused by this disturbance. The aim of this study was to verify the effectiveness of the laser 670 nm, in two different energy densities, in the pain reduction, in rats submitted to a sciatica experimental model. Eighteen rats, divided in 3 groups were used: G1 (n=6 submitted to sciatica and simulated treatment (placebo

  10. The influence of experimentally induced pain on shoulder muscle activity

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Winther, Annika; Dyhre-Poulsen, Poul

    2009-01-01

    Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven...... healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0 degrees...... -105 degrees) at a speed of approximately 120 degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles...

  11. The influence of experimentally induced pain on shoulder muscle activity

    DEFF Research Database (Denmark)

    Diederichsen, L.P.; Winther, A.; Dyhre-Poulsen, P.

    2009-01-01

    Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven...... healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0A degrees......-105A degrees) at a speed of approximately 120A degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder...

  12. Effects of experimentally induced pain and fear of pain on trunk coordination and back muscle activity during walking.

    NARCIS (Netherlands)

    Lamoth, C.J.C.; Daffertshofer, A.; Meijer, O.G.; Moseley, G.; Wuisman, P.I.J.M.; Beek, P.J.

    2004-01-01

    OBJECTIVE: To examine the effects of experimentally induced pain and fear of pain on trunk coordination and erector spinae EMG activity during gait. DESIGN: In 12 healthy subjects, hypertonic saline (acute pain) and isotonic saline (fear of pain) were injected into erector spinae muscle, and

  13. Healthy volunteers can be phenotyped using cutaneous sensitization pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Petersen, Karin; Rowbotham, Michael C

    2013-01-01

    Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repe...... repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models....

  14. Models of experimental epilepsy

    Directory of Open Access Journals (Sweden)

    Fatih Ekici

    2011-03-01

    Full Text Available Epilepsy is the most common serious neurological conditionin the world, with an estimated prevalence of 1% ofthe population. A large number of experimental modelsof seizure and epilepsy have been developed. These experimentalmodels are elicited by chemical convulsants,electrical stimulation, genetic models, structural lesions,physical stimuli (cold, pressure, hyperthermia, electricalin animals. Well-characterized animal models may allowthe understanding of the basic mechanisms underlyingepileptogenesis (it refers to the alteration of a normalneuronal network into a hyperexcitable network in whichrecurrent, spontaneous seizures occur. Moreover, thesemodels might also prove useful in identifying novel therapeuticapproaches to treatment of epilepsy. J Clin ExpInvest 2011; 2(1: 118-123

  15. The Modulation of Pain by Circadian and Sleep-Dependent Processes: A Review of the Experimental Evidence

    DEFF Research Database (Denmark)

    Hagenauer, Megan; Crodelle, Jennifer; Piltz, Sofia Helena

    2017-01-01

    in an effort to identify constraints for the models. While it is well accepted that sleep behavior is regulated by a daily (circadian) timekeeping system and homeostatic sleep drive, the joint modulation of these two primary biological processes on pain sensitivity has not been considered. Under experimental...... disruption. To explore the interaction between these two biological processes using modeling, we first compare the magnitude of their effects across a variety of experimental pain studies in humans. To do this comparison, we normalize the results from experimental pain studies relative to the range...... of physiologically meaningful stimulation levels. Following this normalization, we find that the estimated impact of the daily rhythm and of sleep deprivation on experimental pain measurements is surprisingly consistent across different pain modalities. We also review evidence documenting the impact of circadian...

  16. Inflammation-induced pain sensitization in men and women: does sex matter in experimental endotoxemia?

    Science.gov (United States)

    Wegner, Alexander; Elsenbruch, Sigrid; Rebernik, Laura; Roderigo, Till; Engelbrecht, Elisa; Jäger, Marcus; Engler, Harald; Schedlowski, Manfred; Benson, Sven

    2015-10-01

    A role of the innate immune system is increasingly recognized as a mechanism contributing to pain sensitization. Experimental administration of the bacterial endotoxin lipopolysaccharide (LPS) constitutes a model to study inflammation-induced pain sensitization, but all existing human evidence comes from male participants. We assessed visceral and musculoskeletal pain sensitivity after low-dose LPS administration in healthy men and women to test the hypothesis that women show greater LPS-induced hyperalgesia compared with men. In this randomized, double-blind, placebo-controlled crossover study, healthy men (n = 20) and healthy women using oral contraceptives (n = 20) received an intravenous injection of 0.4 ng/kg body weight LPS or placebo. Pain sensitivity was assessed with established visceral and musculoskeletal pain models (ie, rectal pain thresholds; pressure pain thresholds for different muscle groups), together with a heartbeat perception (interoceptive accuracy) task. Plasma cytokines (tumor necrosis factor-α and interleukin-6) were measured along with state anxiety at baseline and up to 6-hour postinjection. Lipopolysaccharide application led to significant increases in plasma cytokines and state anxiety and decreased interoceptive awareness in men and women (P < 0.001, condition effects), with more pronounced LPS-induced cytokine increases in women (P < 0.05, interaction effects). Although both rectal and pressure pain thresholds were significantly decreased in the LPS condition (all P < 0.05, condition effect), no sex differences in endotoxin-induced sensitization were observed. In summary, LPS-induced systemic immune activation leads to visceral and musculoskeletal hyperalgesia, irrespective of biological sex. These findings support the broad applicability of experimental endotoxin administration as a translational preclinical model of inflammation-induced pain sensitization in both sexes.

  17. Changes of sodium channel expression in experimental painful diabetic neuropathy.

    Science.gov (United States)

    Craner, Matthew J; Klein, Joshua P; Renganathan, Muthukrishnan; Black, Joel A; Waxman, Stephen G

    2002-12-01

    Although pain is experienced by many patients with diabetic neuropathy, the pathophysiology of painful diabetic neuropathy is not understood. Substantial evidence indicates that dysregulated sodium channel gene transcription contributes to hyperexcitability of dorsal root ganglion neurons, which may produce neuropathic pain after axonal transection. In this study, we examined sodium channel mRNA and protein expression in dorsal root ganglion neurons in rats with streptozotocin-induced diabetes and tactile allodynia, using in situ hybridization and immunocytochemistry for sodium channels Na(v)1.1, Na(v)1.3, Na(v)1.6, Na(v)1.7, Na(v)1.8, and Na(v)1.9. Our results show that, in rats with experimental diabetes, there is a significant upregulation of mRNA for the Na(v)1.3, Na(v)1.6, and Na(v)1.9 sodium channels and a downregulation of Na(v)1.8 mRNA 1 and 8 weeks after onset of allodynia. Channel protein levels display parallel changes. Our results demonstrate dysregulated expression of the genes for sodium channels Na(v)1.3, Na(v)1.6, Na(v)1.8, and Na(v)1.9 in dorsal root ganglion neurons in experimental diabetes and suggest that misexpression of sodium channels contributes to neuropathic pain associated with diabetic neuropathy.

  18. Experimental pain in human temporal muscle induced by hypertonic saline, potassium and acidity

    DEFF Research Database (Denmark)

    Jensen, K; Norup, M

    1992-01-01

    The study was aimed at developing a reference model for experimental pain and tenderness in the human temporal muscle by the local injection of hypertonic saline, potassium chloride and acidic phosphate buffer, using isotonic saline as control. The design was randomized and double-blind. Twenty...

  19. Suggestions to Reduce Clinical Fibromyalgia Pain and Experimentally Induced Pain Produce Parallel Effects on Perceived Pain but Divergent Functional MRI-Based Brain Activity.

    Science.gov (United States)

    Derbyshire, Stuart W G; Whalley, Matthew G; Seah, Stanley T H; Oakley, David A

    Hypnotic suggestion is an empirically validated form of pain control; however, the underlying mechanism remains unclear. Thirteen fibromyalgia patients received suggestions to alter their clinical pain, and 15 healthy controls received suggestions to alter experimental heat pain. Suggestions were delivered before and after hypnotic induction with blood oxygen level-dependent (BOLD) activity measured concurrently. Across groups, suggestion produced substantial changes in pain report (main effect of suggestion, F2, 312 = 585.8; p pain report in regions previously associated with pain, including thalamus and anterior cingulate cortex. In controls, BOLD response decreased with pain report. All changes were greater after induction. Region-of-interest analysis revealed largely linear patient responses with increasing pain report. Control responses, however, were higher after suggestion to increase or decrease pain from baseline. Based on behavioral report alone, the mechanism of suggestion could be interpreted as largely similar regardless of the induction or type of pain experience. The functional magnetic resonance imaging data, however, demonstrated larger changes in brain activity after induction and a radically different pattern of brain activity for clinical pain compared with experimental pain. These findings imply that induction has an important effect on underlying neural activity mediating the effects of suggestion, and the mechanism of suggestion in patients altering clinical pain differs from that in controls altering experimental pain. Patient responses imply that suggestions altered pain experience via corresponding changes in pain-related brain regions, whereas control responses imply suggestion engaged cognitive control.

  20. The effect of Cordia platythyrsa on various experimental models of ...

    African Journals Online (AJOL)

    The effect of Cordia platythyrsa on various experimental models of pain and carrageenan induced inflammation. Benedicta N Nkeh-Chungag, Eugene J Ndebia, Joseph T Mbafor, Lonwabo A Dotwana, OO Oyedeji, Jehu E Iputo ...

  1. The Pain Interprofessional Curriculum Design Model.

    Science.gov (United States)

    Watt-Watson, Judy; Lax, Leila; Davies, Robyn; Langlois, Sylvia; Oskarsson, Jon; Raman-Wilms, Lalitha

    2017-06-01

     Although the University of Toronto Centre for the Study of Pain has successfully implemented an Interfaculty Pain Curriculum since 2002, we have never formalized the process in a design model. Therefore, our primary aim was to develop a model that provided an overview of dynamic, interrelated elements that have been important in our experience. A secondary purpose was to use the model to frame an interactive workshop for attendees interested in developing their own pain curricula.  The faculties from Dentistry, Medicine, Nursing, Occupational Therapy, Pharmacy, and Physical Therapy met to develop the model components. Discussion focused on patient-centered pain assessment and management in an interprofessional context, with pain content being based on the International Association for the Study of Pain-Interprofessional Pain Curriculum domains and related core pain competencies. Profession-specific requirements were also considered, including regulatory/course requirements, level of students involved, type of course delivery, and pedagogic strategies.  The resulting Pain Interprofessional Curriculum Design Model includes components that are dynamic, competency-based, collaborative, and interrelated. Key questions important to developing curricular components guide the process. The Model framed two design workshops with very positive responses from international and national attendees.  The Pain Interprofessional Curriculum Design Model is based on established pain curricula and related competencies that are relevant to all health science students at the prelicensure (entry-to-practice) level. The model has been developed from our experience, and the components resonated with workshop attendees from other regions. This Model provides a basis for future interventions in curriculum design and evaluation.

  2. The biopsychosocial model in cancer pain.

    Science.gov (United States)

    Novy, Diane M; Aigner, Carrie J

    2014-06-01

    The purpose of this review is to provide the reader with an up-to-date overview on the biopsychosocial model in cancer pain. This review contains articles published from 2012 to 2014, which advance our understanding of biopsychosocial factors related to the cancer pain experience and psychosocial treatment for cancer pain. Greater depression, anxiety, and distress, and lower quality of life are related to greater pain intensity in cancer patients. Recent publications have expanded on this research by examining how psychosocial factors relate to the development of chronic pain conditions after cancer treatment. Recent publications have also advanced our understanding of psychosocial interventions for cancer pain and symptom management. In the last few years, several reviews have emerged, which have found modest effect sizes for psychosocial interventions in cancer pain management. The biopsychosocial model is a helpful way to comprehensively approach the conceptualization and treatment of pain in cancer patients at all stages of the disease process. We currently have an established base of research on the importance of biopsychosocial model in cancer pain. Our ability to treat patients with cancer pain effectively will improve as we gain a better understanding of which treatments work for which patients.

  3. Characterization of a novel model of tonic heat pain stimulation in healthy volunteers

    DEFF Research Database (Denmark)

    Naert, A.L.; Kehlet, H.; Kupers, R.

    2008-01-01

    model that can be applied without excessive discomfort in the majority of subjects and offers a valuable addition to the armamentarium of experimental pain models. The model can be particularly suitable for brain imaging receptor binding studies which require long stimulation periods Udgivelsesdato......The vast majority of the experimental pain studies have used acute, phasic heat stimuli to investigate the neurobiological mechanisms of pain. However, the validity of these models for understanding clinical forms of pain is questionable. We here describe the characteristics of a model of prolonged...... tonic heat pain stimulation and compared the responses on this test with other measures of pain. In 58 normal volunteers, we applied a 7-min lasting contact heat stimulation of 47 degrees C to the upper leg while participants constantly rated their pain. Average pain rating during the 7-min period was 6...

  4. Beyond pain: modeling decision-making deficits in chronic pain

    Science.gov (United States)

    Hess, Leonardo Emanuel; Haimovici, Ariel; Muñoz, Miguel Angel; Montoya, Pedro

    2014-01-01

    Risky decision-making seems to be markedly disrupted in patients with chronic pain, probably due to the high cost that impose pain and negative mood on executive control functions. Patients’ behavioral performance on decision-making tasks such as the Iowa Gambling Task (IGT) is characterized by selecting cards more frequently from disadvantageous than from advantageous decks, and by switching often between competing responses in comparison with healthy controls (HCs). In the present study, we developed a simple heuristic model to simulate individuals’ choice behavior by varying the level of decision randomness and the importance given to gains and losses. The findings revealed that the model was able to differentiate the behavioral performance of patients with chronic pain and HCs at the group, as well as at the individual level. The best fit of the model in patients with chronic pain was yielded when decisions were not based on previous choices and when gains were considered more relevant than losses. By contrast, the best account of the available data in HCs was obtained when decisions were based on previous experiences and losses loomed larger than gains. In conclusion, our model seems to provide useful information to measure each individual participant extensively, and to deal with the data on a participant-by-participant basis. PMID:25136301

  5. Experimental knee joint pain during strength training and muscle strength gain in healthy subjects

    DEFF Research Database (Denmark)

    Sørensen, T J; Langberg, Henning; Hodges, P W

    2012-01-01

    Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function and t...... and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals.......Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function...

  6. Antinociceptive Interaction of Tramadol with Gabapentin in Experimental Mononeuropathic Pain.

    Science.gov (United States)

    Miranda, Hugo F; Noriega, Viviana; Prieto, Juan Carlos; Zanetta, Pilar; Castillo, Rodrigo; Aranda, Nicolás; Sierralta, Fernando

    2016-08-01

    Neuropathic pain is the result of injury to the nervous system, and different animal models have been established to meet the manifestations of neuropathy. The pharmacotherapy for neuropathic pain includes gabapentin and tramadol, but these are only partially effective when given alone. The aim of this study was to assess the antinociceptive interaction between both drugs using the isobolographic analysis and changes of the IL-1β concentration in a mouse model of neuropathic pain (partial sciatic nerve ligation or PSNL). The i.p. administration of gabapentin (5-100 mg/kg) or tramadol (12.5-100 mg/kg) displayed a dose-dependent antinociception in the hot plate assay of PSNL mice, and effects induced by gabapentin with tramadol were synergistic. Administration of gabapentin or tramadol reversed significantly the increase in the concentration of IL-1β induced by PSNL after either 7 or 14 days and their combination was significantly more potent in reversing the elevated concentration of IL-1β. The synergism obtained by the co-administration of gabapentin and tramadol is proposed to result from action on different mechanisms in pain pathways. Gabapentin or tramadol or their combination modulates the expression of pro-inflammatory cytokine, IL-1β, in a model of mice PSNL which could be due to an inhibition of glial function. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  7. Gender Differences in Response to Experimental Pain among Medical Students from a Western State of India

    Directory of Open Access Journals (Sweden)

    Pratik N Akhani

    2014-02-01

    Full Text Available Background: Pain is one of the most common reasons for patients to seek medical attention and it causes considerable human suffering. Pain is a complex perception that differs enormously among individual patients. Gender plays an important role in how pain is experienced, coped with and treated. Even young healthy individuals often differ in how they perceive and cope with pain. This study was done to investigate gender differences in response to experimental pain among medical students from a western state of India.Methods: A total of 150 medical students (86 boys and 64 girls participated in this interventional study. The Cold Pressor Test was used to exert experimental pain. To study the response, cardiovascular measures (radial pulse, systolic blood pressure and diastolic blood pressure and pain sensitivity parameters (pain threshold, pain tolerance and pain rating were assessed.Results: No significant difference was found in cardiovascular response to experimental pain between both the genders (p>0.05. Pain threshold and pain tolerance were found to be significantly higher in males whereas pain rating was found to be significantly higher in females (p<0.01. Pulse reactivity showed a negative relationship with pain threshold and pain tolerance whereas a positive relationship with pain rating, however no statistically significant relation was found between these measures.Conclusion: Females display greater pain sensitivity than men. Different pain perception might account for gender difference in pulse reactivity.

  8. Attenuation of nociceptive pain and inflammatory disorders by total steroid and terpenoid fraction of Euphorbia tirucalli Linn root in experimental in vitro and in vivo model.

    Science.gov (United States)

    Palit, Partha; Mukherjee, Dhrubojyoti; Mahanta, Poulami; Shadab, Md; Ali, Nahid; Roychoudhury, Shubhadeep; Asad, Md; Mandal, Subhash C

    2017-10-23

    The plant Euphorbia tirucalli Linn has been successfully used as a tribal folk medicine in India and Africa for the management of acute inflammatory, arthritic, nociceptive pain and asthmatic symptoms. The present study was conducted to assess the anti-inflammatory, analgesic, anti-asthmatic and anti-arthritic role of the total steroid and terpenoid rich fractions of the hydro-alcoholic extract of E. tirucalli root (STF-HAETR). STF-HAETR fraction demonstrated 71.25 ± 2.5 and 74.25 ± 5.1% protection against acetic acid-induced pain and central neuropathic pain at 75 and 100 mg/kg doses, respectively. It showed 96.97% protection against acute inflammation at 100 mg/kg with 1.6-fold better activity than the standard drug. The fraction exhibited such efficacy via inhibition of proinflammatory cytokines TNF-α, IFN-γ, by 61.12 and 65.18%, respectively, at 100 μg/mL. Inhibition of cyclooxygenase and Nitric oxide synthase in a dose-dependent manner affirms its analgesic and anti-inflammatory activity. The spectrophotometric analysis reveals that STF-HAETR induces ameliorative effect against heat-induced denaturation of Bovine serum albumin (BSA) and exhibits significant anti-proteinase activity. The plant fraction also demonstrated anti-asthmatic activity by displaying 62.45% protection against histamine induced bronchoconstriction or dyspnoea. Our findings suggest that STF-HAETR could be an effective safe therapeutic agent to treat nociceptive pain, acute inflammation, asthma, and arthritis which may authenticate its traditional use.

  9. Pain Related Fear and Catastrophizing Predict Pain Intensity and Disability Independently Using an Induced Muscle Injury Model

    Science.gov (United States)

    Parr, Jeffrey J.; Borsa, Paul A.; Fillingim, Roger B.; Tillman, Mark D.; Manini, Todd M.; Gregory, Chris M.; George, Steven Z.

    2012-01-01

    Timing of assessment of psychological construct is controversial and results differ based on the model of pain induction. Previous studies have not used an exercise induced injury model to investigate timing of psychological assessment. Exercise induced injury models may be appropriate for these investigations because they approximate clinical pain conditions better than other experimental stimuli. In this study we examined the changes of psychological constructs over time and determined whether timing of assessment affected the construct’s association with reports of pain intensity and disability. One-hundred twenty-six healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Tampa Scale of Kinesiophobia (TSK) prior to inducing muscle injury to the shoulder. The PCS and TSK were measured again 48 and 96 hours post-injury induction. Pain intensity and disability were collected at 48 and 96 hours and served as dependent variables in separate regression models. Results indicated that the FPQ-III had the strongest prediction of pain intensity from baseline to 96 hours. After baseline the PCS and TSK were stronger predictors of pain intensity and disability, respectively. These data provide support for the use of psychological constructs in predicting outcomes from shoulder pain. However, they deviate from the current theoretical model indicating that fear of pain is a consequence of injury and instead suggests that fear of pain before injury may influence reports of pain intensity. Perspective The current study provides evidence that fear of pain can be assessed prior to injury. Furthermore, it supports that after injury pain catastrophizing and kinesiophobia are independently associated with pain and disability. Overall these data suggest that timing of psychological assessment may be an important consideration in clinical environments. PMID:22424914

  10. Effects of ethnicity and gender role expectations of pain on experimental pain: a cross-cultural study.

    Science.gov (United States)

    Alabas, O A; Tashani, O A; Johnson, M I

    2013-05-01

    Gender role expectations of pain (GREP) have been shown to mediate sex differences in experimental pain. Few studies have investigated the role of ethnicity in shaping GREP. The aim of this study was to examine interactions between ethnicity and GREP on experimentally induced pressure and ischaemic pain in Libyan and white British students in their respective countries. Libyan (n = 124) and white British (n = 51) students completed a GREP questionnaire and their response to experimental pain was measured. Blunt pressure pain threshold (PPT) was measured over the 1st interosseous muscle using algometry. Pain intensity and pain unpleasantness (100 mm visual analogue scale) were measured at 1-min intervals during a submaximal effort tourniquet test on the forearm. Multivariate analysis of variance detected significant effects for Sex and Ethnicity on pain measurements. Men had higher PPTs than women (p 0.05). Libyan participants had higher pain intensity (p gender stereotypical attitudes to pain account for differences in pain expression between men and women. © 2012 European Federation of International Association for the Study of Pain Chapters.

  11. Dose-specific effects of transcutaneous electrical nerve stimulation (TENS) on experimental pain: a systematic review.

    Science.gov (United States)

    Claydon, Leica S; Chesterton, Linda S; Barlas, Panos; Sim, Julius

    2011-09-01

    To determine the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) parameter combinations on experimental models in healthy humans. Searches were performed using the electronic databases Ovid MEDLINE, CINAHL, AMED, and Web of Science (from inception to December 2009). Manual searches of journals and reference lists of retrieved trials were also performed. Randomized controlled trials (RCTs) were included in the review if they compared the hypoalgesic effect of TENS relative with placebo and control, using an experimental pain model in healthy human participants. Two reviewers independently selected the trials, assessed their methodologic quality and extracted data. Forty-three RCTs were eligible for inclusion. A best evidence synthesis revealed: Overall "conflicting" (inconsistent findings in multiple RCTs) evidence of TENS efficacy on experimental pain irrespective of TENS parameters used. Overall intense TENS has "moderate" evidence of efficacy (1 high-quality and 2 low-quality trials). Conventional TENS has overall conflicting evidence of efficacy, this is derived from "strong" evidence of efficacy (generally consistent findings in multiple high-quality RCTs) on pressure pain but strong evidence of inefficacy on other pain models. "Limited" evidence (positive findings from 1 RCT) of hypoalgesia exists for some novel parameters. Low-intensity, low-frequency, local TENS has strong evidence of inefficacy. Inappropriate TENS (using "barely perceptible" intensities) has moderate evidence of inefficacy. The level of hypoalgesic efficacy of TENS is clearly dependent on TENS parameter combination selection (defined in terms of intensity, frequency, and stimulation site) and experimental pain model. Future clinical RCTs may consider these TENS dose responses.

  12. Experimental Object-Oriented Modelling

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    and discuss techniques for handling and representing uncertainty when modelling in experimental system development. These techniques are centred on patterns and styles for handling uncertainty in object-oriented software architectures. Tools We present the Knight tool designed for collaborative modelling......This thesis examines object-oriented modelling in experimental system development. Object-oriented modelling aims at representing concepts and phenomena of a problem domain in terms of classes and objects. Experimental system development seeks active experimentation in a system development project...... through, e.g., technical prototyping and active user involvement. We introduce and examine “experimental object-oriented modelling” as the intersection of these practices. The contributions of this thesis are expected to be within three perspectives on models and modelling in experimental system...

  13. Multiple sites and actions of gabapentin-induced relief of ongoing experimental neuropathic pain.

    Science.gov (United States)

    Bannister, Kirsty; Qu, Chaoling; Navratilova, Edita; Oyarzo, Janice; Xie, Jennifer Yanhua; King, Tamara; Dickenson, Anthony H; Porreca, Frank

    2017-08-21

    Gabapentin (GBP) is a first-line therapy for neuropathic pain, but its mechanisms and sites of action remain uncertain. We investigated GBP-induced modulation of neuropathic pain following spinal nerve ligation (SNL) in rats. Intravenous or intrathecal GBP reversed evoked mechanical hypersensitivity and produced conditioned place preference (CPP) and dopamine (DA) release in the nucleus accumbens (NAc) selectively in SNL rats. Spinal GBP also significantly inhibited dorsal horn wide-dynamic-range neuronal responses to a range of evoked stimuli in SNL rats. By contrast, GBP microinjected bilaterally into the rostral anterior cingulate cortex (rACC), produced CPP, and elicited NAc DA release selectively in SNL rats but did not reverse tactile allodynia and had marginal effects on wide-dynamic-range neuronal activity. Moreover, blockade of endogenous opioid signaling in the rACC prevented intravenous GBP-induced CPP and NAc DA release but failed to block its inhibition of tactile allodynia. Gabapentin, therefore, can potentially act to produce its pain relieving effects by (a) inhibition of injury-induced spinal neuronal excitability, evoked hypersensitivity, and ongoing pain and (b) selective supraspinal modulation of affective qualities of pain, without alteration of reflexive behaviors. Consistent with previous findings of pain relief from nonopioid analgesics, GBP requires engagement of rACC endogenous opioid circuits and downstream activation of mesolimbic reward circuits reflected in learned pain-motivated behaviors. These findings support the partial separation of sensory and affective dimensions of pain in this experimental model and suggest that modulation of affective-motivational qualities of pain may be the preferential mechanism of GBP's analgesic effects in patients.

  14. Increased trunk muscle activity during gait after bilateral experimental pain induction in recurrent low back pain patients during a pain-free period

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Sørensen, Brian Østergaard; Brogner, Heidi Marie

    Introduction: Trunk muscle control is consistently altered in persistent low back pain patients during a variety of functions but the effect of experimental pain induction in recurrent low back pain patients during a pain-free period remains unknown. The aim of this study was to investigate...... activity during swing phases in patients compared with control participants indicated persistent sensorimotor changes in recurrent low back patients during a pain-free period. Acknowledgement: The study was supported by Center for Neuroplasticity and Pain (CNAP), SMI, Department of Health Science...

  15. Revisiting the Cartesian model of pain.

    Science.gov (United States)

    Goldberg, Joel S

    2008-01-01

    In modern medicine, the Cartesian or nociceptive concept of chronic pain has been replaced with the biopsychosocial model in both theory and practice. This paper presents an argument along with observations in favor of chronic pain as a pure nociceptive experience separate from suffering and outlines theoretical and practical solutions to improve the diagnosis and treatment of patients who experience chronic pain. Theoretical solutions include increasing inhibitory descending neurotransmitters using monoamine oxidase inhibitors of subtype A in combination with dextroamphetamine, increasing beta endorphin through enzymology and/or ultrasound stimulation of the periaqueductal gray, developing long duration opioid analgesics using spin label probes of morphine and morphine analogs and destructive interference of nociceptive action potentials by eddy currents generated by a variable magnetic field. Practical solutions include prolonging local anesthetic blockade of small pain fibers with patient administered local anesthetic storage devices and abandonment of the multidisciplinary pain clinic.

  16. Biopsychosocial model of chronic recurrent pain

    Directory of Open Access Journals (Sweden)

    Zlatka Rakovec-Felser

    2009-07-01

    Full Text Available Pain is not merely a symptom of disease but a complex independent phenomenon where psychological factors are always present (Sternberg, 1973. Especially by chronic, recurrent pain it's more constructive to think of chronic pain as a syndrome that evolves over time, involving a complex interaction of physiological/organic, psychological, and behavioural processes. Study of chronic recurrent functional pain covers tension form of headache. 50 suffering persons were accidentally chosen among those who had been seeking medical help over more than year ago. We tested their pain intensity and duration, extent of subjective experience of accommodation efforts, temperament characteristics, coping strategies, personal traits, the role of pain in intra- and interpersonal communication. At the end we compared this group with control group (without any manifest physical disorders and with analyse of variance (MANOVA. The typical person who suffers and expects medical help is mostly a woman, married, has elementary or secondary education, is about 40. Pain, seems to appear in the phase of stress-induced psychophysical fatigue, by persons with lower constitutional resistance to different influences, greater irritability and number of physiologic correlates of emotional tensions. Because of their ineffective style of coping, it seems they quickly exhausted their adaptation potential too. Through their higher level of social–field dependence, reactions of other persons (doctor, spouse could be important factors of reinforcement and social learning processes. In managing of chronic pain, especially such as tension headache is, it's very important to involve bio-psychosocial model of pain and integrative model of treatment. Intra- and inter-subjective psychological functions of pain must be recognised as soon as possible.

  17. Reorganized trunk muscle activity during multidirectional floor perturbations after experimental low back pain

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2016-01-01

    Low back pain changes the trunk muscle activity after external perturbations but the relationship between pain intensities and distributions and their effect on the trunk muscle activity remains unclear. The effects of unilateral and bilateral experimental low back pain on trunk muscle activity...... each perturbation was extracted and averaged across perturbations. The difference (ΔRMS-EMG) and absolute difference (absolute ΔRMS-EMG) RMS from baseline conditions were extracted for each muscle during pain conditions and averaged bilaterally for back and abdominal muscle groups. Bilateral compared...... with unilateral pain induced higher VAS scores (P pain areas (P pain (P back (P

  18. Is Pain Perception Altered in People With Depression? A Systematic Review and Meta-Analysis of Experimental Pain Research.

    Science.gov (United States)

    Thompson, Trevor; Correll, Christoph U; Gallop, Katy; Vancampfort, Davy; Stubbs, Brendon

    2016-12-01

    Although clinical studies suggest depressed patients may be more vulnerable to pain, experimental research is equivocal. This meta-analysis aimed to clarify whether depression is associated with altered pain perception in response to noxious stimulation and to identify factors that might influence this association. A search of major electronic databases was conducted to identify experimental studies investigating pain response in depressed participants versus healthy control participants using established pain outcome measures. Random effects meta-analysis of standardized mean differences was conducted on data from 32 studies (N = 1,317). For high-intensity noxious stimulation, overall pain tolerance was similar across depressed and control groups (Hedges g = .09, P = .71, studies = 10). For low-intensity stimulation, a small, but statistically significant higher mean sensory threshold (g = .35, P = .01, studies = 9) and pain threshold (g = .32, P = .02, studies = 25) was observed in depressed participants, suggesting diminished pain. However, considerable heterogeneity in the direction and magnitude of effects was observed, indicating a likely condition-specific effect of depression on pain. Subgroup analysis found that pain threshold/tolerance was increased in depression for exteroceptive (cutaneous) stimulation but decreased for interoceptive (ischemic) stimulation, but that substantial heterogeneity remained. Overall, results provide some support for altered pain processing in depression, but suggest this link is dependent upon modality and additional, unidentified factors. This meta-analysis of experimental studies suggests potential effects of depression on pain perception are variable and likely to depend upon multiple factors. The contrasting pattern for ischemic versus other noxious stimuli suggests that stimulus modality is a key factor, which could help explain discrepancies across clinical and experimental findings. Copyright

  19. Spared nerve injury model to study orofacial pain.

    Science.gov (United States)

    Pozza, Daniel Humberto; Castro-Lopes, José Manuel; Neto, Fani Lourenca; Avelino, António

    2016-03-01

    There are many difficulties in generating and testing orofacial pain in animal models. Thus, only a few and limited models that mimic the human condition are available. The aim of the present research was to develop a new model of trigeminal pain by using a spared nerve injury (SNI) surgical approach in the rat face (SNI-face). Under anaesthesia, a small incision was made in the infraorbital region of adult male Wistar rats. Three of the main infraorbital nerve branches were tightly ligated and a 2 mm segment distal to the ligation was resected. Control rats were sham-operated by exposing the nerves. Chemical hyperalgesia was evaluated 15 days after the surgery by analyzing the time spent in face grooming activity and the number of head withdrawals in response to the orofacial formalin test. SNI-face rats presented a significant increase of the formalin-induced pain-related behaviours evaluated both in the acute and tonic phases (expected biphasic pattern), in comparison to sham controls. The SNI-face model in the rat appears to be a valid approach to evaluate experimental trigeminal pain. Ongoing studies will test the usefulness of this model to evaluate therapeutic strategies for the treatment of orofacial pain.

  20. Pain perception in people with Down syndrome: a synthesis of clinical and experimental research

    Science.gov (United States)

    McGuire, Brian E.; Defrin, Ruth

    2015-01-01

    People with an intellectual disability experience both acute and chronic pain with at least the same frequency as the general population. However, considerably less is known about the pain perception of people with Down syndrome. In this review paper, we evaluated the available clinical and experimental evidence. Some experimental studies of acute pain have indicated that pain threshold was higher than normal but only when using a reaction time method to measure pain sensitivity. However, when reaction time is not part of the calculation of the pain threshold, pain sensitivity in people with Down syndrome is in fact lower than normal (more sensitive to pain). Clinical studies of chronic pain have shown that people with an intellectual disability experience chronic pain and within that population, people with Down syndrome also experience chronic pain, but the precise prevalence of chronic pain in Down syndrome has yet to be established. Taken together, the literature suggests that people with Down syndrome experience pain, both acute and chronic, with at least the same frequency as the rest of the population. Furthermore, the evidence suggests that although acute pain expression appears to be delayed, once pain is registered, there appears to be a magnified pain response. We conclude by proposing an agenda for future research in this area. PMID:26283936

  1. Pain assessment in animal models: do we need further studies?

    Directory of Open Access Journals (Sweden)

    Gigliuto C

    2014-05-01

    , number, size, distribution and communication of vessels in dermal skin, epidermal–dermal junctions, the immunoreactivity of peptide nerve fibers, distribution of nociceptive and non-nociceptive fiber classes, and changes in axonal excitability, swines seem to provide the most suitable animal model for pain assessment. Locomotor function, clinical signs, and measurements (respiratory rate, heart rate, blood pressure, temperature, electromyography, behavior (bright/quiet, alert, responsive, depressed, unresponsive, plasma concentration of substance P and cortisol, vocalization, lameness, and axon reflex vasodilatation by laser Doppler imaging have been used to assess pain, but none of these evaluations have proved entirely satisfactory. It is necessary to identify new methods for evaluating pain in large animals (particularly pigs, because of their similarities to humans. This could lead to improved assessment of pain and improved analgesic treatment for both humans and laboratory animals.Keywords: pain assessment, experimental model, translational research

  2. Self-reported pain and disability outcomes from an endogenous model of muscular back pain

    Directory of Open Access Journals (Sweden)

    George Steven Z

    2011-02-01

    Full Text Available Abstract Background Our purpose was to develop an induced musculoskeletal pain model of acute low back pain and examine the relationship among pain, disability and fear in this model. Methods Delayed onset muscle soreness was induced in 52 healthy volunteers (23 women, 17 men; average age 22.4 years; average BMI 24.3 using fatiguing trunk extension exercise. Measures of pain intensity, unpleasantness, and location, and disability, were tracked for one week after exercise. Results Pain intensity ranged from 0 to 68 with 57.5% of participants reporting peak pain at 24 hours and 32.5% reporting this at 48 hours. The majority of participants reported pain in the low back with 33% also reporting pain in the legs. The ratio of unpleasantness to intensity indicated that the sensation was considered more unpleasant than intense. Statistical differences were noted in levels of reported disability between participants with and without leg pain. Pain intensity at 24 hours was correlated with pain unpleasantness, pain area and disability. Also, fear of pain was associated with pain intensity and unpleasantness. Disability was predicted by sex, presence of leg pain, and pain intensity; however, the largest amount of variance was explained by pain intensity (27% of a total 40%. The second model, predicting pain intensity only included fear of pain and explained less than 10% of the variance in pain intensity. Conclusions Our results demonstrate a significant association between pain and disability in this model in young adults. However, the model is most applicable to patients with lower levels of pain and disability. Future work should include older adults to improve the external validity of this model.

  3. Sex differences in how social networks and relationship quality influence experimental pain sensitivity

    National Research Council Canada - National Science Library

    Vigil, Jacob M; Rowell, Lauren N; Chouteau, Simone; Chavez, Alexandre; Jaramillo, Elisa; Neal, Michael; Waid, David

    2013-01-01

    This is the first study to examine how both structural and functional components of individuals' social networks may moderate the association between biological sex and experimental pain sensitivity...

  4. Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity

    DEFF Research Database (Denmark)

    Vaegter, Henrik Bjarke; Graven-Nielsen, Thomas

    2016-01-01

    between subgroups. Cuff algometry was performed on lower legs in 400 chronic pain patients to assess pressure pain threshold (cPPT), pressure pain tolerance (cPTT), temporal summation of pain (TSP: increase in pain scores to ten repeated stimulations), and conditioned pain modulation (CPM: increase in c......PPT during cuff pain conditioning on the contralateral leg). Heat detection (HDT) and heat pain thresholds (HPT) at clinical painful and non-painful body areas were assessed. Based on TSP and CPM four distinct groups were formed: Group 1 (n=85) had impaired CPM and facilitated TSP. Group 2 (n=148) had...... impaired CPM and normal TSP. Group 3 (n=45) had normal CPM and facilitated TSP. Group 4 (n=122) had normal CPM and normal TSP. Group 1 showed more pain regions compared with the other three groups (PTSP plays an important role in widespread pain. Group 1...

  5. Experimental reduction of pain catastrophizing modulates pain report but not spinal nociception as verified by mediation analyses.

    Science.gov (United States)

    Terry, Ellen L; Thompson, Kathryn A; Rhudy, Jamie L

    2015-08-01

    Pain catastrophizing is associated with enhanced pain; however, the mechanisms by which it modulates pain are poorly understood. Evidence suggests that catastrophizing modulates supraspinal processing of pain but does not modulate spinal nociception (as assessed by nociceptive flexion reflex [NFR]). Unfortunately, most NFR studies have been correlational. To address this, this study experimentally reduced catastrophizing to determine whether it modulates spinal nociception (NFR). Healthy pain-free participants (N = 113) were randomly assigned to a brief 30-minute catastrophizing reduction manipulation or a control group that received pain education. Before and after manipulations, 2 types of painful stimuli were delivered to elicit (1) NFR (single trains of stimuli) and (2) temporal summation of NFR (3 stimulations at 2 Hz). After each set of stimuli, participants were asked to report their pain intensity and unpleasantness, as well as their situation-specific catastrophizing. Manipulation checks verified that catastrophizing was effectively reduced. Furthermore, pain intensity and unpleasantness to both stimulation types were reduced by the catastrophizing manipulation, effects that were mediated by catastrophizing. Although NFRs were not affected by the catastrophizing manipulation, temporal summation of NFR was reduced. However, this effect was not mediated by catastrophizing. These results indicate that reductions in catastrophizing lead to reductions in pain perception but do not modulate spinal nociception and provides further evidence that catastrophizing modulates pain at the supraspinal, not the spinal, level.

  6. The effect of cognitive bias modification for interpretation on avoidance of pain during an acute experimental pain task.

    Science.gov (United States)

    Jones, Emma Blaisdale; Sharpe, Louise

    2014-08-01

    Research confirms that patients with chronic pain show a tendency to interpret ambiguous stimuli as pain related. However, whether modifying these interpretive pain biases impacts pain outcomes is unknown. This study aimed to demonstrate that interpretation biases towards pain can be modified, and that changing these biases influences pain outcomes in the cold pressor task. One hundred and six undergraduate students were randomly allocated to receive either threatening or reassuring information regarding the cold pressor. They also were randomly allocated to 1 of 2 conditions in the Ambiguous Scenarios Task, in which they were trained to have either a threatening interpretation of pain (pain bias condition) or a nonthreatening interpretation of pain (no pain bias condition). Therefore, the study had a 2 (threat/reassuring)×2 (pain bias/no pain bias) design. Analyses showed that a bias was induced contingent on condition, and that the threat manipulation was effective. Participants in the pain bias condition hesitated more before doing the cold pressor task than those in the no pain bias condition, as did those in the threat compared with the reassurance condition. The major finding was that interpretive bias mediated the relationship between bias condition and hesitance time, supporting the causal role of interpretive biases for avoidance behaviors in current chronic pain models. No differences were found on other pain outcomes regarding bias or threat, and the efficacy of the bias modification was not impacted by different levels of threat. These results suggest that cognitive bias modification should be further explored as a potential intervention in pain. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  7. Experimental muscle pain changes the spatial distribution of upper trapezius muscle activity during sustained contraction.

    Science.gov (United States)

    Madeleine, Pascal; Leclerc, Fredéric; Arendt-Nielsen, Lars; Ravier, Philippe; Farina, Dario

    2006-11-01

    To investigate the effect of local excitation of nociceptive muscle afferents on the spatial distribution of muscle activity. Surface electromyographic (EMG) signals were recorded from the upper trapezius muscle of 10 healthy volunteers with a 5 x 13 electrode grid during 90-s isometric contractions before, during, 15 and 30 min after intramuscular injection of hypertonic (painful) or isotonic (non-painful) saline. From the multi-channel EMG recordings, two-dimensional maps of root mean square and mean power frequency were obtained. The centre of gravity of the root mean square map was used to quantify global changes in the spatial distribution of muscle activity. During sustained contractions, average root mean square increased, average mean frequency decreased and the centre of gravity moved cranially. During experimental muscle pain, compared to before injection, the average root mean square decreased and there was a caudal shift of the centre of gravity. Fifteen minutes after the painful injection the centre of gravity returned to its original position. Short-term dynamic reorganization of the spatial distribution of muscle activity occurred in response to nociceptive afferent input. The study furnishes an extension of the pain adaptation model indicating heterogeneous inhibition of muscle activity.

  8. Cytogenetics and experimental models.

    Science.gov (United States)

    Toretsky, J A; Helman, L J

    1997-07-01

    The use of cytogenetics has led to significant improvement in the diagnoses and classification of sarcomas. Many of the major sarcomas have been to have characteristic tumor-specific chromosomal translocations that are currently used in the diagnosis of these tumors. In the past year, a subset of Ewing's family of tumors and myxoid liposarcomas, which lack one of the characteristic translocations, were found to carry related translocations. New technologies such as a spectral karyotyping will likely increase out ability to identify additional tumor-specific translocations. The emergence of genetic alterations as prognostic factors, as illustrated by Ewing's family of tumors, osteosarcoma, and p53 expression in soft tissue sarcomas in general, is discussed. The review concludes with laboratory applications derived from either tumor cytogenetic or gene function abnormalities that are related to tumor-specific translocations. It is anticipated that advances in diagnosis, prognosis, and modeling will translate into future therapeutic advances.

  9. Patterns of experimentally induced pain in pericranial muscles

    DEFF Research Database (Denmark)

    Schmidt-Hansen, Peter Thede; Svensson, Peter; Jensen, Troels Staehelin

    2006-01-01

    (VAS) and the perceived area of pain was drawn on anatomical maps. The pain areas were measured and the localization determined by a new centre-of-gravity method. The PPTs were lowest on the sternocleidomastoid muscle (anova: P VAS pain scored highest following injection...

  10. Psychological resilience, pain catastrophizing, and positive emotions: perspectives on comprehensive modeling of individual pain adaptation.

    Science.gov (United States)

    Sturgeon, John A; Zautra, Alex J

    2013-03-01

    Pain is a complex construct that contributes to profound physical and psychological dysfunction, particularly in individuals coping with chronic pain. The current paper builds upon previous research, describes a balanced conceptual model that integrates aspects of both psychological vulnerability and resilience to pain, and reviews protective and exacerbating psychosocial factors to the process of adaptation to chronic pain, including pain catastrophizing, pain acceptance, and positive psychological resources predictive of enhanced pain coping. The current paper identifies future directions for research that will further enrich the understanding of pain adaptation and espouses an approach that will enhance the ecological validity of psychological pain coping models, including introduction of advanced statistical and conceptual models that integrate behavioral, cognitive, information processing, motivational and affective theories of pain.

  11. Managing painful chronic wounds: the Wound Pain Management Model

    DEFF Research Database (Denmark)

    Price, Patricia; Fogh, Karsten; Glynn, Chris

    2007-01-01

    Chronic wound pain is not well understood and the literature is limited. Six of 10 patients venous leg ulcer experience pain with their ulcer, and similar trends are observed for other chronic wounds. Chronic wound pain can lead to depression and the feeling of constant tiredness. Pain related...... to the wound should be handled as one of the main priorities in chronic wound management together with addressing the cause. Management of pain in chronic wounds depends on proper assessment, reporting and documenting patient experiences of pain. Assessment should be based on six critical dimensions...... document persistent wound pain and not to develop a treatment and monitoring strategy to improve the lives of persons with chronic wounds. Unless wound pain is optimally managed, patient suffering and costs to health care systems will increase. Udgivelsesdato: 2007-Apr...

  12. Reliability of four experimental mechanical pain tests in children

    DEFF Research Database (Denmark)

    Søe, Ann-Britt Langager; Thomsen, Lise L; Tornoe, Birte

    2013-01-01

    In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim was a...... was also to study the intersession reliability of the following four tests: (1) Total Tenderness Score; (2) PPT; (3) Visual Analog Scale score at suprapressure pain threshold; and (4) area under the curve (stimulus-response functions for pressure versus pain)....

  13. Experimental quadriceps muscle pain impairs knee joint control during walking

    DEFF Research Database (Denmark)

    Henriksen, Marius; Alkjaer, Tine; Lund, Hans

    2007-01-01

    Pain is a cardinal symptom in musculoskeletal diseases involving the knee joint, and aberrant movement patterns and motor control strategies are often present in these patients. However, the underlying neuromuscular mechanisms linking pain to movement and motor control are unclear. To investigate......, and EMG activity in the VM and VL muscles was reduced. Compressive forces, adduction moments, knee joint kinematics, and hamstring EMG activity were unaffected by pain. Interestingly, the observed changes persisted when the pain had vanished. The results demonstrate that muscle pain modulated the function...

  14. Movement does not promote recovery of motor output following acute experimental muscle pain

    DEFF Research Database (Denmark)

    Schabrun, Siobhan M.; Palsson, Thorvaldur Skuli; Thapa, Tribikram

    2018-01-01

    Objective.:  To examine the effect of motor activity on the magnitude and duration of altered corticomotor output following experimental muscle pain. Design. : Experimental, pre-post test. Setting. : University laboratory. Subjects. : Twenty healthy individuals. Methods.:  Participants were rando....... Understanding corticomotor depression in the postpain period and what factors promote recovery has relevance for clinical pain syndromes where ongoing motor dysfunction, in the absence of pain, may predispose to symptom persistence or recurrence....

  15. Women with dysmenorrhea are hypersensitive to experimental deep muscle pain across the menstrual cycle.

    Science.gov (United States)

    Iacovides, Stella; Baker, Fiona C; Avidon, Ingrid; Bentley, Alison

    2013-10-01

    Primary dysmenorrhea is a common painful condition in women that recurs every month across the reproductive years. The recurrent nociceptive input into the central nervous system that occurs during menstruation each month in women with dysmenorrhea is hypothesized to lead to increased sensitivity to painful stimuli. We investigated whether women with primary dysmenorrhea are hyperalgesic to deep muscle pain induced by a cleanly nociceptive method of hypertonic saline injection. Pain stimulation was applied both within an area of referred menstrual pain (lower back) and at a remote site outside of referred menstrual pain (forearm) in 12 healthy women with severe dysmenorrhea and 9 healthy women without dysmenorrhea, at 3 phases of the menstrual cycle: menstruation and follicular and luteal phases. Women rated their pain severity on a 100-mm visual analog scale every 30 seconds after injection until the pain subsided. In both groups of women, menstrual cycle phase had no effect on the reported intensity and duration of muscle pain. However, women with dysmenorrhea had increased sensitivity to experimental muscle pain both at the site of referred pain and at a remote nonpainful site, as assessed by peak pain severity visual analog scale rating, area under the visual analog scale curve, and pain duration, compared to women without dysmenorrhea. These data show that women with severe primary dysmenorrhea, who experience monthly menstrual pain, are hyperalgesic to deep muscle pain compared to women without dysmenorrhea. Our findings that dysmenorrheic women are hyperalgesic to a clinically relevant, deep muscle pain in areas within and outside of referred menstrual pain indicates lasting changes in pain sensitivity outside of the painful period during menstruation. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  16. Healthy Volunteers Can Be Phenotyped Using Cutaneous Sensitization Pain Models

    Science.gov (United States)

    Rowbotham, Michael C.; Dahl, Jørgen B.

    2013-01-01

    Background Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models. Methods We performed post-hoc analyses of 10 completed healthy volunteer studies (n = 342 [409 repeated measurements]). Three different models were used to induce secondary hyperalgesia to monofilament stimulation: the heat/capsaicin sensitization (H/C), the brief thermal sensitization (BTS), and the burn injury (BI) models. Three studies included both the H/C and BTS models. Results Within-subject compared to between-subject variability was low, and there was substantial strength of agreement between repeated induction-sessions in most studies. The intraclass correlation coefficient (ICC) improved little with repeated testing beyond two sessions. There was good agreement in categorizing subjects into ‘small area’ (1st quartile [75%]) responders: 56–76% of subjects consistently fell into same ‘small-area’ or ‘large-area’ category on two consecutive study days. There was moderate to substantial agreement between the areas of secondary hyperalgesia induced on the same day using the H/C (forearm) and BTS (thigh) models. Conclusion Secondary hyperalgesia induced by experimental heat pain models seem a consistent measure of sensitization in pharmacodynamic and physiological research. The analysis indicates that healthy volunteers can be phenotyped based on their pattern of sensitization by the heat [and heat plus capsaicin] pain models. PMID:23671631

  17. Healthy volunteers can be phenotyped using cutaneous sensitization pain models.

    Directory of Open Access Journals (Sweden)

    Mads U Werner

    Full Text Available BACKGROUND: Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models. METHODS: We performed post-hoc analyses of 10 completed healthy volunteer studies (n = 342 [409 repeated measurements]. Three different models were used to induce secondary hyperalgesia to monofilament stimulation: the heat/capsaicin sensitization (H/C, the brief thermal sensitization (BTS, and the burn injury (BI models. Three studies included both the H/C and BTS models. RESULTS: Within-subject compared to between-subject variability was low, and there was substantial strength of agreement between repeated induction-sessions in most studies. The intraclass correlation coefficient (ICC improved little with repeated testing beyond two sessions. There was good agreement in categorizing subjects into 'small area' (1(st quartile [75%] responders: 56-76% of subjects consistently fell into same 'small-area' or 'large-area' category on two consecutive study days. There was moderate to substantial agreement between the areas of secondary hyperalgesia induced on the same day using the H/C (forearm and BTS (thigh models. CONCLUSION: Secondary hyperalgesia induced by experimental heat pain models seem a consistent measure of sensitization in pharmacodynamic and physiological research. The analysis indicates that healthy volunteers can be phenotyped based on their pattern of sensitization by the heat [and heat plus capsaicin] pain models.

  18. Analyzing musculoskeletal neck pain, measured as present pain and periods of pain, with three different regression models: a cohort study

    Directory of Open Access Journals (Sweden)

    Hagberg Mats

    2009-06-01

    Full Text Available Abstract Background In the literature there are discussions on the choice of outcome and the need for more longitudinal studies of musculoskeletal disorders. The general aim of this longitudinal study was to analyze musculoskeletal neck pain, in a group of young adults. Specific aims were to determine whether psychosocial factors, computer use, high work/study demands, and lifestyle are long-term or short-term factors for musculoskeletal neck pain, and whether these factors are important for developing or ongoing musculoskeletal neck pain. Methods Three regression models were used to analyze the different outcomes. Pain at present was analyzed with a marginal logistic model, for number of years with pain a Poisson regression model was used and for developing and ongoing pain a logistic model was used. Presented results are odds ratios and proportion ratios (logistic models and rate ratios (Poisson model. The material consisted of web-based questionnaires answered by 1204 Swedish university students from a prospective cohort recruited in 2002. Results Perceived stress was a risk factor for pain at present (PR = 1.6, for developing pain (PR = 1.7 and for number of years with pain (RR = 1.3. High work/study demands was associated with pain at present (PR = 1.6; and with number of years with pain when the demands negatively affect home life (RR = 1.3. Computer use pattern (number of times/week with a computer session ≥ 4 h, without break was a risk factor for developing pain (PR = 1.7, but also associated with pain at present (PR = 1.4 and number of years with pain (RR = 1.2. Among life style factors smoking (PR = 1.8 was found to be associated to pain at present. The difference between men and women in prevalence of musculoskeletal pain was confirmed in this study. It was smallest for the outcome ongoing pain (PR = 1.4 compared to pain at present (PR = 2.4 and developing pain (PR = 2.5. Conclusion By using different regression models different

  19. Sex Differences in Parent and Child Pain Ratings during an Experimental Child Pain Task

    Directory of Open Access Journals (Sweden)

    Erin C Moon

    2008-01-01

    Full Text Available Research in the field of pediatric pain has largely ignored the role of fathers in their children’s pain experiences. The first objective of the present study was to examine the effect of the presence of mothers versus fathers on children’s subjective ratings, facial expressions and physiological responses to acute pain. The second objective was to examine whether child and parent sex influence parents’ proxy ratings of their children’s pain. The final objective was to compare levels of agreement between mothers’ and fathers’ assessments of their children’s pain. Participants included 73 children (37 boys, 36 girls, four to 12 years of age, along with 32 fathers and 41 mothers. Children undertook the cold pressor pain task while observed by one of their parents. During the task, the children’s heart rates and facial expressions were recorded. Children provided self-reports and parents provided proxy reports of child pain intensity using the seven-point Faces Pain Scale. Neither child nor parent sex had a significant impact on children’s subjective reports, facial expressions or heart rates in response to acute pain. Fathers gave their sons higher pain ratings than their daughters, whereas mothers’ ratings of their sons’ and daughters’ pain did not differ. Kappa statistics and t tests revealed that fathers tended to be more accurate judges of their children’s pain than mothers. Overall, this research highlights the importance of examining both parent and child sex differences in pediatric pain research.

  20. Effects of coping statements on experimental pain in chronic pain patients

    Directory of Open Access Journals (Sweden)

    Daniela Roditi

    2009-08-01

    Full Text Available Daniela Roditi, Michael E Robinson, Nola LitwinsDepartment of Clinical and Health Psychology, University of Florida, Gainesville, FL, USAAbstract: The present study measured the effects of catastrophizing self-statements and positive coping self-statements on cold pressor-induced pain. Participants were 58 adult chronic pain patients with current facial pain. It was hypothesized that catastrophizing would lead to a decrease in pain endurance whereas positive coping would lead to an increase in pain endurance. It was also hypothesized that catastrophizing would lead to an increase in peak pain intensity whereas positive coping would lead to a decrease in peak pain intensity. At pretest, participants submerged their nondominant hand in the cold pressor. Pain sensitivity ranges (PSR were subsequently determined by calculating the difference between tolerance and threshold times. Ratings of peak pain intensity were measured using a pressure sensitive bladder/transducer. Participants underwent random assignment to either a catastrophizing group or a positive coping self-statement group. ANCOVA results revealed that on average, participants employing catastrophizing statements as a coping strategy experienced significantly lower PSR (M = 35.53, SD = 39.71 compared to participants employing positive coping self-statements (M = 73.70, SD = 86.14 when controlling for pretest PSR. Group assignment had no significant influence on peak pain intensity ratings. Thus, our results reveal that manipulation of coping causes changes in pain endurance.Keywords: catastrophizing, coping, expectation, pain sensitivity

  1. An experimental investigation of the effects of preferred and relaxing music listening on pain perception.

    Science.gov (United States)

    Mitchell, Laura A; MacDonald, Raymond A R

    2006-01-01

    This study investigates the effects of music listening on perception and tolerance of experimentally induced cold pressor pain. Fifty-four participants (34 females, 20 males) each underwent 3 cold pressor trials while listening to (a) white noise, (b) specially designed relaxation music, and (c) their own chosen music. Tolerance time, pain intensity on visual analog scale, and the pain rating index of the McGill Pain Questionnaire and perceived control over the pain were measured in each condition. While listening to their own preferred music, male and female participants tolerated the painful stimulus significantly longer than during both the relaxation music and control conditions. However, only female participants rated the intensity of the pain as significantly lower in the preferred music condition. Both male and female participants reported feeling significantly more control when listening to their preferred music. It is suggested that personal preference is an influential factor when considering the efficacy of music listening for pain relief.

  2. Effect of helium-neon laser auriculotherapy on experimental pain threshold.

    Science.gov (United States)

    King, C E; Clelland, J A; Knowles, C J; Jackson, J R

    1990-01-01

    This study was conducted to examine the effects of helium-neon laser auriculotherapy on experimental pain threshold. Eighty healthy female and male subjects, aged 18 to 39 years, were assigned randomly to one of two treatment groups. Subjects in the Experimental Group (n = 41) received laser stimulation, and subjects in the Control Group (n = 39) received sham stimulation to appropriate acupuncture points on the left ear. Experimental pain threshold at the ipsilateral wrist was determined with an electrical stimulus immediately before and after treatment. The mean change (posttreatment minus pretreatment) for the Experimental Group was greater than the mean change for the Control Group (p less than .05). The Experimental Group demonstrated a statistically significant (p less than .05) increase in mean pain threshold after treatment, but the Control Group did not. Results indicate that helium-neon laser auriculotherapy can increase experimental pain threshold and suggest a possible alternative for patients intolerant of transcutaneous electrical nerve stimulation.

  3. [Neither Descartes nor Freud? current pain models in psychosomatic medicine].

    Science.gov (United States)

    Egloff, N; Egle, U T; von Känel, R

    2008-05-14

    Models explaining chronic pain based on the mere presence or absence of peripheral somatic findings or which view pain of psychological origin when there is no somatic explanation, have their shortcomings. Current scientific knowledge calls for distinct pain concepts, which integrate neurobiological and neuropsychological aspects of pain processing.

  4. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  5. The pattern of expression of the voltage-gated sodium channels Na(v)1.8 and Na(v)1.9 does not change in uninjured primary sensory neurons in experimental neuropathic pain models.

    Science.gov (United States)

    Decosterd, Isabelle; Ji, Ru-Rong; Abdi, Salahadin; Tate, Simon; Woolf, Clifford J

    2002-04-01

    A spared nerve injury of the sciatic nerve (SNI) or a segmental lesion of the L5 and L6 spinal nerves (SNL) lead to behavioral signs of neuropathic pain in the territory innervated by adjacent uninjured nerve fibers, while a chronic constriction injury (CCI) results in pain sensitivity in the affected area. While alterations in voltage-gated sodium channels (VGSCs) have been shown to contribute to the generation of ectopic activity in the injured neurons, little is known about changes in VGSCs in the neighboring intact dorsal root ganglion (DRG) neurons, even though these cells begin to fire spontaneously. We have now investigated changes in the expression of the TTX-resistant VGSCs, Nav1.8 (SNS/PN3) and Nav1.9 (SNS2/NaN) by immunohistochemistry in rat models of neuropathic pain both with an intermingling of intact and degenerated axons in the nerve stump (SNL and CCI) and with a co-mingling in the same DRG of neurons with injured and uninjured axons (sciatic axotomy and SNI). The expression of Nav1.8 and Nav1.9 protein was abolished in all injured DRG neurons, in all models. In intact DRGs and in neighboring non-injured neurons, the expression and the distribution among the A- and C-fiber neuronal populations of Nav1.8 and Nav1.9 was, however, unchanged. While it is unlikely, therefore, that a change in the expression of TTX-resistant VGSCs in non-injured neurons contributes to neuropathic pain, it is essential that molecular alterations in both injured and non-injured neurons in neuropathic pain models are investigated.

  6. The interruptive effect of pain in a multitask environment: an experimental investigation.

    Science.gov (United States)

    Van Ryckeghem, Dimitri M L; Crombez, Geert; Eccleston, Christopher; Liefooghe, Baptist; Van Damme, Stefaan

    2012-02-01

    Daily life is characterized by the need to stop, start, repeat, and switch between multiple tasks. Here, we experimentally investigate the effects of pain, and its anticipation, in a multitask environment. Using a task-switching paradigm, participants repeated and switched between 3 tasks, of which 1 predicted the possible occurrence of pain. Half of the participants received low intensity pain (N = 30), and half high intensity pain (N = 30). Results showed that pain interferes with the performance of a simultaneous task, independent of the pain intensity. Furthermore, pain interferes with the performance on a subsequent task. These effects are stronger with high intensity pain than with low intensity pain. Finally, and of particular importance in this study, interference of pain on a subsequent task was larger when participants switched to another task than when participants repeated the same task. This article is concerned with the interruptive effect of pain on people's task performance by using an adapted task-switching paradigm. This adapted paradigm may offer unique possibilities to investigate how pain interferes with task performance while people repeat and switch between multiple tasks in a multitask environment. Copyright © 2012 American Pain Society. Published by Elsevier Inc. All rights reserved.

  7. Perception of experimental pain is reduced after provoked waking from rapid eye movement sleep.

    Science.gov (United States)

    Daya, Vivek G; Bentley, Alison J

    2010-06-01

    Patients with chronic pain often complain of pain when they wake at night, but the accuracy of their perception of the pain after waking at night is unknown. While cognitive functions are reduced for a short time after waking from sleep, a situation known as sleep inertia, it is unclear how sleep inertia may affect the perception of pain. We investigated the effects of sleep inertia on the perception of experimentally induced pain. Fourteen male volunteers were exposed to a randomized thermal heat stimulus of 43.1 degrees C 'hot' and 46.5 degrees C 'hurting' during provoked waking from Stage 2 sleep, slow wave sleep and rapid eye movement (REM) sleep. Subjects rated their pain on awakening on a Visual Analogue Scale at 30 s after awakening and each minute thereafter for 5 min. We found no change in pain perception over the 5-min period irrespective of temperature used or sleep stage. However, perceived pain when awoken abruptly from REM sleep was significantly lower than the awake score for both the hot (P = 0.0069) and hurting (P = 0.0025) temperatures. Pain perception when woken from Stage 2 sleep or slow wave sleep was not significantly different from perception when awake. Our findings indicate that sleep inertia reduces pain perception when awoken abruptly from REM. This suggests that patients who wake up in pain either perceive accurately the pain they are experiencing, or at worst underestimate the level of pain if woken from REM sleep.

  8. A 5-HT Antagonist (UP 26-91 versus Codeine and Placebo in a Human Experimental Pain Study

    Directory of Open Access Journals (Sweden)

    Lars Arendt-Nielsen

    2000-01-01

    Full Text Available BACKGROUND: This double-blind, randomized, crossover study compared the potential analgesic effect of the serotonin receptor antagonist UP 26-91 (50 mg, 150 mg and 300 mg with that of codeine (100 mg and placebo by use of different human experimental pain models.

  9. Experimental Modeling of Dynamic Systems

    DEFF Research Database (Denmark)

    Knudsen, Morten Haack

    2006-01-01

    An engineering course, Simulation and Experimental Modeling, has been developed that is based on a method for direct estimation of physical parameters in dynamic systems. Compared with classical system identification, the method appears to be easier to understand, apply, and combine with physical...

  10. Body awareness and responses to experimentally Induced pain

    National Research Council Canada - National Science Library

    M. Minev; M. Petkova; B. Petrova; R. Strebkova

    2017-01-01

    PURPOSE. The aim of this study is to discuss personal and demographic factors that influence the relationship between physical activity and awareness of one's own body, as well as the pain response...

  11. Body awareness and responses to experimentally Induced pain

    Directory of Open Access Journals (Sweden)

    M. Minev

    2017-09-01

    Full Text Available PURPOSE. The aim of this study is to discuss personal and demographic factors that influence the relationship between physical activity and awareness of one's own body, as well as the pain response (threshold and tolerance of pain, situational anxiety and personality. In the study 38 healthy individual- volunteers, students in Trakia University - Stara Zagora were selected. All participants were divided into two groups: actively involved in individual or team sport (n = 19 and healthy normaly active subjects (non-athletes, n = 19. The age of the study participants ranged between 18 and 39 years, while the gender breakdown was as follows: men - 22 women – 16. Methods: Psychological Questionnaires: Body Awareness Questionnaire that asks subjects to rate, on a 4 point scale, the degree to which they were currently experiencing symptoms of sympathetic arousal, State Trait Anger Scale, and State Trait Anxiety Scale. Objective methods (cold pressure test are used only to determine the pain sensation and pain tolerance thresholds. The results of investigation support significant differences between athletes and non-athletes in pain thershold, body awareness and anxiety. The study conclusions discuss body awareness as an increasing factor for pain resistance in athletes and as an integral part of the learning process among them.

  12. Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Nielsen, Thomas Graven; Aaboe, Jens

    2010-01-01

    Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease...... progression. This study investigated changes in knee moments during walking following experimental knee pain in healthy volunteers, and whether these changes replicated the joint moments observed in medial knee OA patients....

  13. Objective markers of the analgesic response to morphine in experimental pain research

    DEFF Research Database (Denmark)

    Brokjær, Anne; Olesen, Anne Estrup; Kreilgaard, Mads

    2015-01-01

    of morphine on three objective pharmacodynamic markers (pupil diameter, prolactin concentration and resting electroencephalography (EEG)) and compare the changes from placebo with subjective analgesia on experimental muscle pain for convergent validation. METHODS: Fifteen healthy male participants received......INTRODUCTION: In experimental pain research the effect of opioids is normally assessed by verbal subjective response to analgesia. However, as many confounders in pain assessment exist, objective bed-side assessment of the effect is highly warranted. Therefore, we aimed to assess the effect...... placebo or 30mg rectal morphine at two separate sessions. At baseline and several time points after drug administration, the central effects of morphine were assessed by experimental muscle pain, pupil diameter, prolactin concentration and resting EEG. RESULTS: Morphine increased tolerance to muscle pain...

  14. The Gate Theory of Pain Revisited: Modeling Different Pain Conditions with a Parsimonious Neurocomputational Model

    Science.gov (United States)

    Ropero Peláez, Francisco Javier; Taniguchi, Shirley

    2016-01-01

    The gate control theory of pain proposed by Melzack and Wall in 1965 is revisited through two mechanisms of neuronal regulation: NMDA synaptic plasticity and intrinsic plasticity. The Melzack and Wall circuit was slightly modified by using strictly excitatory nociceptive afferents (in the original arrangement, nociceptive afferents were considered excitatory when they project to central transmission neurons and inhibitory when projecting to substantia gelatinosa). The results of our neurocomputational model are consistent with biological ones in that nociceptive signals are blocked on their way to the brain every time a tactile stimulus is given at the same locus where the pain was produced. In the computational model, the whole set of parameters, independently of their initialization, always converge to the correct values to allow the correct computation of the circuit. To test the model, other painful conditions were analyzed: phantom limb pain, wind-up and wind-down pain, breakthrough pain, and demyelinating syndromes like Guillain-Barré and multiple sclerosis. PMID:27088014

  15. The Gate Theory of Pain Revisited: Modeling Different Pain Conditions with a Parsimonious Neurocomputational Model

    Directory of Open Access Journals (Sweden)

    Francisco Javier Ropero Peláez

    2016-01-01

    Full Text Available The gate control theory of pain proposed by Melzack and Wall in 1965 is revisited through two mechanisms of neuronal regulation: NMDA synaptic plasticity and intrinsic plasticity. The Melzack and Wall circuit was slightly modified by using strictly excitatory nociceptive afferents (in the original arrangement, nociceptive afferents were considered excitatory when they project to central transmission neurons and inhibitory when projecting to substantia gelatinosa. The results of our neurocomputational model are consistent with biological ones in that nociceptive signals are blocked on their way to the brain every time a tactile stimulus is given at the same locus where the pain was produced. In the computational model, the whole set of parameters, independently of their initialization, always converge to the correct values to allow the correct computation of the circuit. To test the model, other painful conditions were analyzed: phantom limb pain, wind-up and wind-down pain, breakthrough pain, and demyelinating syndromes like Guillain-Barré and multiple sclerosis.

  16. Vitamin D, race, and experimental pain sensitivity in older adults with knee osteoarthritis.

    Science.gov (United States)

    Glover, T L; Goodin, B R; Horgas, A L; Kindler, L L; King, C D; Sibille, K T; Peloquin, C A; Riley, J L; Staud, R; Bradley, L A; Fillingim, R B

    2012-12-01

    Low circulating serum levels of 25-hydroxyvitamin D (referred to hereafter as vitamin D) have been correlated with many health conditions, including chronic pain. Recent clinical practice guidelines define vitamin D levels deficient and levels of 21-29 ng/ml as insufficient. Vitamin D insufficiency, including the most severe levels of deficiency, is more prevalent in black Americans. Ethnic and race group differences have been reported in both clinical and experimental pain, with black Americans reporting increased pain. The purpose of this study was to examine whether variations in vitamin D levels contribute to race differences in knee osteoarthritis pain. The sample consisted of 94 participants (74% women), including 45 blacks and 49 whites with symptomatic knee osteoarthritis. Their average age was 55.8 years (range 45-71 years). Participants completed a questionnaire on knee osteoarthritis symptoms and underwent quantitative sensory testing, including measures of sensitivity to heat-induced and mechanically induced pain. Blacks had significantly lower levels of vitamin D compared to whites, demonstrated greater clinical pain, and showed greater sensitivity to heat-induced and mechanically induced pain. Low levels of vitamin D predicted increased experimental pain sensitivity, but did not predict self-reported clinical pain. Group differences in vitamin D levels significantly predicted group differences in heat pain and pressure pain thresholds at the index knee and ipsilateral forearm. These data demonstrate that race differences in experimental pain are mediated by differences in the vitamin D level. Vitamin D deficiency may be a risk factor for increased knee osteoarthritis pain in black Americans. Copyright © 2012 by the American College of Rheumatology.

  17. Isometric force production parameters during normal and experimental low back pain conditions

    Directory of Open Access Journals (Sweden)

    Blouin Jean-Sébastien

    2005-02-01

    Full Text Available Abstract Background The control of force and its between-trial variability are often taken as critical determinants of motor performance. Subjects performed isometric trunk flexion and extension forces without and with experiment pain to examine if pain yields changes in the control of trunk forces. The objective of this study is to determine if experimental low back pain modifies trunk isometric force production. Methods Ten control subjects participated in this study. They were required to exert 50 and 75% of their isometric maximal trunk flexion and extension torque. In a learning phase preceding the non painful and painful trials, visual and verbal feedbacks were provided. Then, subjects were asked to perform 10 trials without any feedback. Time to peak torque, time to peak torque variability, peak torque variability as well as constant and absolute error in peak torque were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak torque achieved. Results Absolute and constant errors were higher in the presence of a painful electrical stimulation. Furthermore, peak torque variability for the higher level of force was increased with in the presence of experimental pain. The linear regressions between peak dF/dt, time to peak dF/dt and peak torque were similar for both conditions. Experimental low back pain yielded increased absolute and constant errors as well as a greater peak torque variability for the higher levels of force. The control strategy, however, remained the same between the non painful and painful condition. Cutaneous pain affects some isometric force production parameters but modifications of motor control strategies are not implemented spontaneously. Conclusions It is hypothesized that adaptation of motor strategies to low back pain is implemented gradually over time. This would enable LBP patients to perform their daily tasks with presumably less pain and more

  18. The effects of mindful attention and state mindfulness on acute experimental pain among adolescents.

    Science.gov (United States)

    Petter, Mark; McGrath, Patrick J; Chambers, Christine T; Dick, Bruce D

    2014-06-01

    Attention-based coping strategies for pain are widely used in pediatric populations. The purpose of this study was to test a novel mindful attention manipulation on adolescent's experimental pain responses. Furthermore, the relationship between state mindfulness and experimental pain was examined. A total of 198 adolescents were randomly assigned to a mindful attention manipulation or control group prior to an experimental pain task. Participants completed measures of state mindfulness immediately prior to the pain task, and situational catastrophizing and pain intensity following the task. Overall the manipulation had no effect on pain. Secondary analysis showed that meditation experience moderated the effect of the manipulation. State mindfulness predicted pain outcomes, with reductions in situational catastrophizing mediating this relationship. The mindful attention manipulation was effective among adolescents with a regular meditation practice. State mindfulness was related to ameliorated pain responses, and these effects were mediated by reduced catastrophizing. © The Author 2014. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Experimental low back pain decreased trunk muscle activity in currently asymptomatic recurrent low back pain patients during step tasks

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2018-01-01

    Low back pain (LBP) patients demonstrate reorganized trunk muscle activity but if similar changes are manifest in recurrent LBP patients (R-LBP) during asymptomatic periods remains unknown. In 26 healthy and 27 currently asymptomatic R-LBP participants electromyographic activity (EMG) was recorded...... experimental NRS scores were higher (Ppain conditions (Ppain decreased Delta-RMS-EMG in m. iliocostalis and bilateral pain decreased Delta-RMS-EMG in all back and gluteal muscles during step tasks...... from trunk and gluteal muscles during series of stepping up and down on a step bench before and during experimentally intramuscular induced unilateral and bilateral LBP. Pain intensity was assessed by numeric rating scale (NRS) scores. Root-mean-square EMG (RMS-EMG) normalized to maximal voluntary...

  20. THE EXPERIMENTAL MODEL OF OSTEONECROSIS

    Directory of Open Access Journals (Sweden)

    G. I. Netylko

    2010-01-01

    Full Text Available The experimental investigation for the purpose of modeling of knee osteonecrosis were performed in 36 rats. The chronic renal insufficiency by means of left nephrectomy and electrocoagulation in 25% cortical substance of right kidney was induced before 6 months till experiment with subsequent introduction of 0,1% adrenalin solution and methylprednisolone in paraarticular structures. The results of experiment showed the polyetiologic feature of disease.

  1. Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.

    Science.gov (United States)

    Marshall, Andrew G; Lee-Kubli, Corinne; Azmi, Shazli; Zhang, Michael; Ferdousi, Maryam; Mixcoatl-Zecuatl, Teresa; Petropoulos, Ioannis N; Ponirakis, Georgios; Fineman, Mark S; Fadavi, Hassan; Frizzi, Katie; Tavakoli, Mitra; Jeziorska, Maria; Jolivalt, Corinne G; Boulton, Andrew J M; Efron, Nathan; Calcutt, Nigel A; Malik, Rayaz A

    2017-05-01

    Impaired rate-dependent depression (RDD) of the Hoffman reflex is associated with reduced dorsal spinal cord potassium chloride cotransporter expression and impaired spinal γ-aminobutyric acid type A receptor function, indicative of spinal inhibitory dysfunction. We have investigated the pathogenesis of impaired RDD in diabetic rodents exhibiting features of painful neuropathy and the translational potential of this marker of spinal inhibitory dysfunction in human painful diabetic neuropathy. Impaired RDD and allodynia were present in type 1 and type 2 diabetic rats but not in rats with type 1 diabetes receiving insulin supplementation that did not restore normoglycemia. Impaired RDD in diabetic rats was rapidly normalized by spinal delivery of duloxetine acting via 5-hydroxytryptamine type 2A receptors and temporally coincident with the alleviation of allodynia. Deficits in RDD and corneal nerve density were demonstrated in patients with painful diabetic neuropathy compared with healthy control subjects and patients with painless diabetic neuropathy. Spinal inhibitory dysfunction and peripheral small fiber pathology may contribute to the clinical phenotype in painful diabetic neuropathy. Deficits in RDD may help identify patients with spinally mediated painful diabetic neuropathy who may respond optimally to therapies such as duloxetine. © 2017 by the American Diabetes Association.

  2. The updated experimental proteinoid model

    Science.gov (United States)

    Fox, S. W.; Nakashima, T.; Przybylski, A.; Syren, R. M.

    1982-01-01

    The experimental proteinoid model includes new results indicating that polymers sufficiently rich in basic amino acid catalyze the synthesis of peptides from ATP and amino acids and of oligonucleotides from ATP. The need for simulation syntheses of amino acids yielding significant proportions of basic amino acids is now in focus. The modeled simultaneous protocellular synthesis of peptides and polynucleotides is part of a more comprehensive proposal for the origin of the coded genetic mechanism. The finding of membrane and action potentials in proteinoid microspheres, with or without added lecithin, is reported. The crucial nature of a nonrandom matrix for protocells is developed.

  3. A computational model unifies apparently contradictory findings concerning phantom pain

    National Research Council Canada - National Science Library

    Boström, Kim J; de Lussanet, Marc H E; Weiss, Thomas; Puta, Christian; Wagner, Heiko

    2014-01-01

    ...) as a cause of phantom pain. However, it was recently found that BOLD activity during voluntary movements of the phantom positively correlates with phantom pain rating, giving rise to a model of persistent representation...

  4. Psychological Factors Predict Local and Referred Experimental Muscle Pain: A Cluster Analysis in Healthy Adults

    Science.gov (United States)

    Lee, Jennifer E.; Watson, David; Frey-Law, Laura A.

    2012-01-01

    Background Recent studies suggest an underlying three- or four-factor structure explains the conceptual overlap and distinctiveness of several negative emotionality and pain-related constructs. However, the validity of these latent factors for predicting pain has not been examined. Methods A cohort of 189 (99F; 90M) healthy volunteers completed eight self-report negative emotionality and pain-related measures (Eysenck Personality Questionnaire-Revised; Positive and Negative Affect Schedule; State-Trait Anxiety Inventory; Pain Catastrophizing Scale; Fear of Pain Questionnaire; Somatosensory Amplification Scale; Anxiety Sensitivity Index; Whiteley Index). Using principal axis factoring, three primary latent factors were extracted: General Distress; Catastrophic Thinking; and Pain-Related Fear. Using these factors, individuals clustered into three subgroups of high, moderate, and low negative emotionality responses. Experimental pain was induced via intramuscular acidic infusion into the anterior tibialis muscle, producing local (infusion site) and/or referred (anterior ankle) pain and hyperalgesia. Results Pain outcomes differed between clusters (multivariate analysis of variance and multinomial regression), with individuals in the highest negative emotionality cluster reporting the greatest local pain (p = 0.05), mechanical hyperalgesia (pressure pain thresholds; p = 0.009) and greater odds (2.21 OR) of experiencing referred pain compared to the lowest negative emotionality cluster. Conclusion Our results provide support for three latent psychological factors explaining the majority of the variance between several pain-related psychological measures, and that individuals in the high negative emotionality subgroup are at increased risk for (1) acute local muscle pain; (2) local hyperalgesia; and (3) referred pain using a standardized nociceptive input. PMID:23165778

  5. The Effect of Parental Modeling on Child Pain Responses: The Role of Parent and Child Sex.

    Science.gov (United States)

    Boerner, Katelynn E; Chambers, Christine T; McGrath, Patrick J; LoLordo, Vincent; Uher, Rudolf

    2017-06-01

    Social modeling is a process by which pain behaviors are learned, and research has found parents act as models for their children's behavior. Despite social learning theory predicting that same-sex models have greater effect, no experimental investigation to date has examined the role of sex of the model or observer in social learning of pediatric pain. The present study recruited 168 parent-child dyads (equal father-son, father-daughter, mother-son, and mother-daughter dyads) in which children were generally healthy and 6 to 8 years old. Unbeknownst to their child, parents were randomly assigned to exaggerate their expression of pain, minimize their expression of pain, or act naturally during the cold pressor task (CPT). Parents completed the CPT while their child observed, then children completed the CPT themselves. Children whose parents were in the exaggerate condition reported higher anxiety than children of parents in the minimize condition. Additionally, girls in the exaggerate condition rated their overall pain intensity during the CPT significantly higher than boys in the same condition. No child sex differences were observed in pain intensity for the control or minimize conditions. Parent expressions of pain affects children's anxiety, and sex-specific effects of parental exaggerated pain expression on children's own subsequent pain experience are present. This article describes how parental expressions of pain influence children's pain and anxiety, specifically examining the relevance of parent and child sex in this process. These findings have implications for children of parents with chronic pain, or situations in which parents experience pain in the presence of their child (eg, vaccinations). Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. Experimental tonic hand pain modulates the corticospinal plasticity induced by a subsequent hand deafferentation.

    Science.gov (United States)

    Mavromatis, N; Gagné, M; Voisin, J I A V; Reilly, K T; Mercier, C

    2016-08-25

    Sensorimotor reorganization is believed to play an important role in the development and maintenance of phantom limb pain, but pain itself might modulate sensorimotor plasticity induced by deafferentation. Clinical and basic research support this idea, as pain prior to amputation increases the risk of developing post-amputation pain. The aim of this study was to examine the influence of experimental tonic cutaneous hand pain on the plasticity induced by temporary ischemic hand deafferentation. Sixteen healthy subjects participated in two experimental sessions (Pain, No Pain) in which transcranial magnetic stimulation was used to assess corticospinal excitability in two forearm muscles (flexor carpi radialis and flexor digitorum superficialis) before (T0, T10, T20, and T40) and after (T60 and T75) inflation of a cuff around the wrist. The cuff was inflated at T45 in both sessions and in the Pain session capsaicin cream was applied on the dorsum of the hand at T5. Corticospinal excitability was significantly greater during the Post-inflation phase (p=0.002) and increased similarly in both muscles (p=0.861). Importantly, the excitability increase in the Post-inflation phase was greater for the Pain than the No-Pain condition (p=0.006). Post-hoc analyses revealed a significant difference between the two conditions during the Post-inflation phase (p=0.030) but no difference during the Pre-inflation phase (p=0.601). In other words, the corticospinal facilitation was greater when pain was present prior to cuff inflation. These results indicate that pain can modulate the plasticity induced by another event, and could partially explain the sensorimotor reorganization often reported in chronic pain populations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Experimenter Effects on Pain Reporting in Women Vary across the Menstrual Cycle

    Directory of Open Access Journals (Sweden)

    Jacob M. Vigil

    2015-01-01

    Full Text Available Background. Separate lines of research have shown that menstrual cycling and contextual factors such as the gender of research personnel influence experimental pain reporting. Objectives. This study examines how brief, procedural interactions with female and male experimenters can affect experimentally reported pain (cold pressor task, CPT across the menstrual cycle. Methods. Based on the menstrual calendars 94 naturally cycling women and 38 women using hormonal contraceptives (Mage=19.83,  SD=3.09 were assigned to low and high fertility groups. This assignment was based on estimates of their probability of conception given their current cycle day. Experimenters (12 males, 7 females engaged in minimal procedural interactions with participants before the CPT was performed in solitude. Results. Naturally cycling women in the high fertility group showed significantly higher pain tolerance (81 sec, d=.79 following interactions with a male but not a female experimenter. Differences were not found for women in the low fertility or contraceptive groups. Discussion. The findings illustrate that menstrual functioning moderates the effect that experimenter gender has on pain reporting in women. Conclusion. These findings have implications for standardizing pain measurement protocols and understanding how basic biopsychosocial mechanisms (e.g., person-perception systems can modulate pain experiences.

  8. Side effects of pain and analgesia in animal experimentation.

    Science.gov (United States)

    Jirkof, Paulin

    2017-03-22

    This review highlights selected effects of untreated pain and of widely used analgesics such as opioids, non-steroid anti-inflammatory drugs and antipyretics, to illustrate the relevance of carefully planned, appropriate and controlled analgesia for greater reproducibility in animal experiments involving laboratory rodents.

  9. Altered expression of the voltage-gated calcium channel subunit alpha(2)delta-1: A comparison between two experimental models of epilepsy and a sensory nerve ligation model of neuropathic pain

    Czech Academy of Sciences Publication Activity Database

    Nieto-Rostro, M.; Sandhu, G.; Bauer, C. S.; Jiruška, Přemysl; Jefferys, J. G. R.; Dolphin, A. C.

    2014-01-01

    Roč. 283, Dec (2014), s. 124-137 ISSN 0306-4522 R&D Projects: GA MZd(CZ) NT14489 Institutional support: RVO:67985823 Keywords : calcium channel * dorsal root ganglion (DRG) * alpha2delta subunit * epilepsy * neuropathic pain * reactive gliosis Subject RIV: FH - Neurology Impact factor: 3.357, year: 2014

  10. Gender role affects experimental pain responses: a systematic review with meta-analysis.

    Science.gov (United States)

    Alabas, O A; Tashani, O A; Tabasam, G; Johnson, M I

    2012-10-01

    Gender role refers to the culturally and socially constructed meanings that describe how women and men should behave in certain situations according to feminine and masculine roles learned throughout life. The aim of this meta-analysis was to evaluate the relationship between gender role and experimental pain responses in healthy human participants. We searched computerized databases for studies published between January 1950 and May 2011 that had measured gender role in healthy human adults and pain response to noxious stimuli. Studies were entered into a meta-analysis if they calculated a correlation coefficient (r) for gender role and experimental pain. Searches yielded 4465 'hits' and 13 studies were eligible for review. Sample sizes were 67-235 participants and the proportion of female participants was 45-67%. Eight types of gender role instrument were used. Meta-analysis of six studies (406 men and 539 women) found a significant positive correlation between masculine and feminine personality traits and pain threshold and tolerance, with a small effect size (r = 0.17, p = 0.01). Meta-analysis of four studies (263 men and 297 women) found a significant negative correlation between gender stereotypes specific to pain and pain threshold and tolerance, with a moderate effect size (r = -0.41, p Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales. © 2012 European Federation of International Association for the Study of Pain Chapters.

  11. The Genetic Influences on Oxycodone Response Characteristics in Human Experimental Pain

    DEFF Research Database (Denmark)

    Olesen, Anne Estrup; Sato, Hiroe; Nielsen, Lecia Møller

    2015-01-01

    Human experimental pain studies are of value to study basic pain mechanisms under controlled conditions. The aim of this study was to investigate whether genetic variation across selected mu-, kappa- and delta-opioid receptor genes (OPRM1, OPRK1and OPRD1, respectively) influenced analgesic response...... PTT (n = 41) were included. Genetic associations with pain outcomes were explored. Nineteen opioid receptor genetic polymorphisms were included in this study. Variability in oxycodone response to skin heat was associated with OPRM1 single-nucleotide polymorphisms (SNPs) rs589046 (P ... to oxycodone in healthy volunteers. Experimental multimodal, multitissue pain data from previously published studies carried out in Caucasian volunteers were used. Data on thermal skin pain tolerance threshold (PTT) (n = 37), muscle pressure PTT (n = 31), mechanical visceral PTT (n = 43) and thermal visceral...

  12. Epithelial Ovarian Cancer Experimental Models

    Science.gov (United States)

    Lengyel, E; Burdette, JE; Kenny, HA; Matei, D; Pilrose, J; Haluska, P.; Nephew, KP; Hales, DB; Stack, MS

    2014-01-01

    Epithelial ovarian cancer (OvCa) is associated with high mortality and, as the majority (>75%) of women with OvCa have metastatic disease at the time of diagnosis, rates of survival have not changed appreciably over 30 years. A mechanistic understanding of OvCa initiation and progression is hindered by the complexity of genetic and/or environmental initiating events and lack of clarity regarding the cell(s) or tissue(s) of origin. Metastasis of OvCa involves direct extension or exfoliation of cells and cellular aggregates into the peritoneal cavity, survival of matrix-detached cells in a complex ascites fluid phase, and subsequent adhesion to the mesothelium lining covering abdominal organs to establish secondary lesions containing host stromal and inflammatory components. Development of experimental models to recapitulate this unique mechanism of metastasis presents a remarkable scientific challenge and many approaches used to study other solid tumors (lung, colon, and breast, for example) are not transferable to OvCa research given the distinct metastasis pattern and unique tumor microenvironment. This review will discuss recent progress in the development and refinement of experimental models to study OvCa. Novel cellular, three-dimensional organotypic, and ex vivo models are considered and the current in vivo models summarized. The review critically evaluates currently available genetic mouse models of OvCa, the emergence of xenopatients, and the utility of the hen model to study OvCa prevention, tumorigenesis, metastasis, and chemoresistance. As these new approaches more accurately recapitulate the complex tumor microenvironment, it is predicted that new opportunities for enhanced understanding of disease progression, metastasis and therapeutic response will emerge. PMID:23934194

  13. Experimental pain sensitivity in women with temporomandibular disorders and pain-free controls: the relationship to orofacial muscular contraction and cardiovascular responses.

    Science.gov (United States)

    Mohn, Christine; Vassend, Olav; Knardahl, Stein

    2008-05-01

    Chronic pain may result both from a generalized hypersensitivity to acute pain, suggestive of central sensitization processes, and dysfunction of the endogenous pain regulatory system. One purpose of this study was to compare experimental pain sensitivity at several anatomic sites in temporomandibular disorder (TMD) patients and pain-free controls during baseline and after standardized mechanical load of the orofacial region. A second purpose was to compare the pain-modulating effects of cardiovascular responses in TMD patients and pain-free controls. Experimental pain was induced by electrocutaneous stimulation of the dorsal left hand and pressure algometry at the right masseter muscle and the sternum. The pain sensitivity of the orofacial region was manipulated by isometric contraction of the masseter muscles. Elevations of mean arterial pressure and heart rate were induced by a simulated job interview. At baseline, the TMD patients exhibited a significantly higher electrocutaneous pain threshold. Relative to the healthy controls, the TMD patients reported increased electrocutaneous and pressure pain sensitivity after isometric contraction of the orofacial region. In addition, there were correlations between mean arterial pressure and pain sensitivity in the TMD group only. Significant increases in generalized pain sensitivity occurred in the TMD group, but not in the control group, after isometric contraction of the orofacial muscles, suggestive of a central sensitization process in TMD. Moreover, only in the TMD group there were significant associations between cardiovascular responsesand pain sensitivity, challenging previous assumptions of this relationship occurring mainly in pain-free individuals.

  14. Effects of restricted environmental stimulation: enhancement of hypnotizability for experimental and chronic pain control.

    Science.gov (United States)

    Barabasz, A F; Barabasz, M

    1989-07-01

    Enhancement of hypnotizability and pain tolerance has been demonstrated using restricted environmental stimulation therapy (REST) with university students as Ss (A. F. Barabasz, 1982). The purpose of the present study was to determine whether or not similar results could be obtained with chronic pain patients. Ss consisted of outpatients in treatment for conditions in which pain is prominent who also demonstrated low hypnotizability after repeated hypnosis plateau sessions. 2 groups of Ss were exposed to REST. Situational demand characteristics (Orne, 1962) favored an increase in hypnotizability for REST Group 1 (high demand). REST Group 2 (low demand) was exposed to situational demand characteristics designed to disguise the experimental hypothesis. 2 groups of control Ss were exposed to the same alternative demand characteristic manipulations as the experimental groups, but environmental stimulation was maintained. The Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and E. R. Hilgard (1962), including a posthypnotic suggestion for an anesthetic reaction, and an ischemic pain test were administered prior to treatment and again immediately following treatment. After 6 hours of REST, significant increases in SHSS:C scores were found for high-demand and low-demand experimental Ss, as well as for high-demand control Ss. No such increase was found for low-demand controls. Significant decreases in pain scores were found for both high- and low-demand experimental groups. No significant pain score decreases were found for either control group, suggesting a relatively weak effect of demand characteristics. An independent postexperimental inquiry suggested all Ss believed they received active treatments. The inquiry, conducted 10-15 days after the experiment, also revealed a majority of experimental Ss were using hypnosis on a daily basis to reduce pain with a substantial decrease in pain medication. Only 2 control Ss (highest in hypnotizability

  15. The effects of brief mindfulness meditation training on experimentally induced pain.

    Science.gov (United States)

    Zeidan, Fadel; Gordon, Nakia S; Merchant, Junaid; Goolkasian, Paula

    2010-03-01

    This study investigated the effects of brief mindfulness meditation training on ratings of painful electrical stimulation. In Experiment 1, we used a 3-day (20 min/d) mindfulness meditation intervention and measured pain ratings before and after the intervention. Participants' numerical ratings of pain to "low" and "high" electrical stimulation significantly decreased after meditation training. Pain sensitivity, measured by change in stimulus intensity thresholds, also decreased after training. We investigated, in Experiment 2, how well relaxation and a math distraction task attenuated experimental pain. Math distraction but not relaxation reduced high pain ratings. There was no reduction in pain sensitivity in these participants. In Experiment 3, we directly compared the effects of meditation with math distraction and relaxation conditions. Our findings indicated significant effects of both meditation and math distraction. Consistent with what was observed in Experiment 1, these participants also demonstrated a decrease in pain sensitivity after meditation training. Changes in the mindfulness and anxiety assessments suggest that meditation's analgesic effects are related to reduced anxiety and the enhanced ability to focus on the present moment. Our findings indicate that a brief 3-day mindfulness meditation intervention was effective at reducing pain ratings and anxiety scores when compared with baseline testing and other cognitive manipulations. The brief meditation training was also effective at increasing mindfulness skills. Copyright 2010 American Pain Society. Published by Elsevier Inc. All rights reserved.

  16. Chronic stress moderates the impact of social exclusion on pain tolerance: an experimental investigation.

    Science.gov (United States)

    Pieritz, Karoline; Schäfer, Sarina J; Strahler, Jana; Rief, Winfried; Euteneuer, Frank

    2017-01-01

    Experiences of social pain due to social exclusion may be processed in similar neural systems that process experiences of physical pain. The present study aimed to extend the findings on social exclusion and pain by examining the impact of social exclusion on an affective (ie, heat pain tolerance) and a sensory component of pain (ie, heat pain intensity). Whether a potential effect may be moderated by chronic life stress, social status, or social sup-port was further examined. A community-based sample of 59 women was studied. Social exclusion and inclusion were experimentally manipulated by using a virtual ball-tossing game called Cyberball in which participants were randomly assigned to either being excluded or being included by two other virtual players. Heat pain tolerance and intensity were assessed before and after the game. Potential psychosocial moderators were assessed via a questionnaire. The main finding of this study is that chronic stress moderates the impact of social exclusion on pain tolerance (psocially excluded participants showed a lower heat pain tolerance than participants who were socially included. Contrary to the authors' hypothesis, pain sensitivity was increased in socially included participants compared with socially excluded participants after the game (psocial exclusion.

  17. Experimental pain leads to reorganisation of trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    in one day, with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40 s without and with presence of experimental pain. Surface EMG signals were recorded from four parts of the trapezius. The centroid of exposure variation analysis along the time axis...... was lower during computer work with active pauses when compared with passive one in all muscle parts (P rest time decreased in ascending part. The results of this study showed a more variable...... trapezius activity pattern and increased activity with active compared with passive pauses, a lowered trapezius rest with presence of experimental pain, and increased activity in the transverse and ascending parts of trapezius due to experimental pain during computer work. Acute pain led to muscle...

  18. The role of periodontal ASIC3 in orofacial pain induced by experimental tooth movement in rats.

    Science.gov (United States)

    Gao, Meiya; Long, Hu; Ma, Wenqiang; Liao, Lina; Yang, Xin; Zhou, Yang; Shan, Di; Huang, Renhuan; Jian, Fan; Wang, Yan; Lai, Wenli

    2016-12-01

    This study aimed to clarify the roles of Acid-sensing ion channel 3 (ASIC3) in orofacial pain following experimental tooth movement. Sixty male Sprague-Dawley rats were divided into the experimental group (40g, n = 30) and the sham group (0g, n = 30). Closed coil springs were ligated between maxillary incisor and molars to achieve experimental tooth movement. Rat grimace scale (RGS) scores were assessed at 0, 1, 3, 5, 7, and 14 days after the placement of the springs. ASIC3 immunostaining was performed and the expression levels of ASIC3 were measured through integrated optical density/area in Image-Pro Plus 6.0. Moreover, 18 rats were divided into APETx2 group (n = 6), amiloride group (n = 6), and vehicle group (n = 6), and RGS scores were obtained compared among them to verify the roles of ASIC3 in orofacial pain following tooth movement. ASIC3 expression levels became significantly higher in the experimental group than in sham group on 1, 3, and 5 days and became similar on 7 and 14 days. Pain levels (RGS scores) increased in both groups and were significantly higher in the experimental group on 1, 3, 5, and 7 days and were similar on 14 days. Periodontal ASIC3 expression levels were correlated with orofacial pain levels following experimental tooth movement. Periodontal administrations of ASIC3 antagonists (APETx2 and amiloride) could alleviate pain. This study needs to be better evidenced by RNA interference of ASIC3 in periodontal tissues in rats following experimental tooth movement. Moreover, we hope further studies would concentrate on the pain perception of ASIC3 knockout (ASIC3(-/-)) mice. Our results suggest that periodontal ASIC3 plays an important role in orofacial pain induced by experimental tooth movement. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain

    Science.gov (United States)

    2011-01-01

    Background Neck-shoulder pain conditions, e.g., chronic trapezius myalgia, have been associated with sensory disturbances such as increased sensitivity to experimentally induced pain. This study investigated pain sensitivity in terms of bilateral pressure pain thresholds over the trapezius and tibialis anterior muscles and pain responses after a unilateral hypertonic saline infusion into the right legs tibialis anterior muscle and related those parameters to intensity and area size of the clinical pain and to psychological factors (sleeping problems, depression, anxiety, catastrophizing and fear-avoidance). Methods Nineteen women with chronic non-traumatic neck-shoulder pain but without simultaneous anatomically widespread clinical pain (NSP) and 30 age-matched pain-free female control subjects (CON) participated in the study. Results NSP had lower pressure pain thresholds over the trapezius and over the tibialis anterior muscles and experienced hypertonic saline-evoked pain in the tibialis anterior muscle to be significantly more intense and locally more widespread than CON. More intense symptoms of anxiety and depression together with a higher disability level were associated with increased pain responses to experimental pain induction and a larger area size of the clinical neck-shoulder pain at its worst. Conclusion These results indicate that central mechanisms e.g., central sensitization and altered descending control, are involved in chronic neck-shoulder pain since sensory hypersensitivity was found in areas distant to the site of clinical pain. Psychological status was found to interact with the perception, intensity, duration and distribution of induced pain (hypertonic saline) together with the spreading of clinical pain. The duration and intensity of pain correlated negatively with pressure pain thresholds. PMID:21992460

  20. An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain

    Directory of Open Access Journals (Sweden)

    Persson Ann L

    2011-10-01

    Full Text Available Abstract Background Neck-shoulder pain conditions, e.g., chronic trapezius myalgia, have been associated with sensory disturbances such as increased sensitivity to experimentally induced pain. This study investigated pain sensitivity in terms of bilateral pressure pain thresholds over the trapezius and tibialis anterior muscles and pain responses after a unilateral hypertonic saline infusion into the right legs tibialis anterior muscle and related those parameters to intensity and area size of the clinical pain and to psychological factors (sleeping problems, depression, anxiety, catastrophizing and fear-avoidance. Methods Nineteen women with chronic non-traumatic neck-shoulder pain but without simultaneous anatomically widespread clinical pain (NSP and 30 age-matched pain-free female control subjects (CON participated in the study. Results NSP had lower pressure pain thresholds over the trapezius and over the tibialis anterior muscles and experienced hypertonic saline-evoked pain in the tibialis anterior muscle to be significantly more intense and locally more widespread than CON. More intense symptoms of anxiety and depression together with a higher disability level were associated with increased pain responses to experimental pain induction and a larger area size of the clinical neck-shoulder pain at its worst. Conclusion These results indicate that central mechanisms e.g., central sensitization and altered descending control, are involved in chronic neck-shoulder pain since sensory hypersensitivity was found in areas distant to the site of clinical pain. Psychological status was found to interact with the perception, intensity, duration and distribution of induced pain (hypertonic saline together with the spreading of clinical pain. The duration and intensity of pain correlated negatively with pressure pain thresholds.

  1. Sex differences in how social networks and relationship quality influence experimental pain sensitivity.

    Science.gov (United States)

    Vigil, Jacob M; Rowell, Lauren N; Chouteau, Simone; Chavez, Alexandre; Jaramillo, Elisa; Neal, Michael; Waid, David

    2013-01-01

    This is the first study to examine how both structural and functional components of individuals' social networks may moderate the association between biological sex and experimental pain sensitivity. One hundred and fifty-two healthy adults (mean age = 22yrs., 53% males) were measured for cold pressor task (CPT) pain sensitivity (i.e., intensity ratings) and core aspects of social networks (e.g., proportion of friends vs. family, affection, affirmation, and aid). Results showed consistent sex differences in how social network structures and intimate relationship functioning modulated pain sensitivity. Females showed higher pain sensitivity when their social networks consisted of a higher proportion of intimate types of relationship partners (e.g., kin vs. non kin), when they had known their network partners for a longer period of time, and when they reported higher levels of logistical support from their significant other (e.g., romantic partner). Conversely, males showed distinct patterns in the opposite direction, including an association between higher levels of logistical support from one's significant other and lower CPT pain intensity. These findings show for the first time that the direction of sex differences in exogenous pain sensitivity is likely dependent on fundamental components of the individual's social environment. The utility of a social-signaling perspective of pain behaviors for examining, comparing, and interpreting individual and group differences in experimental and clinical pain reports is discussed.

  2. The Roles of Ethnicity, Sex, and Parental Pain Modeling in Rating of Experienced and Imagined Pain Events

    Science.gov (United States)

    Boissoneault, Jeff; Bunch, Jennifer R.; Robinson, Michael

    2015-01-01

    To investigate the association of ethnicity, sex, and parental pain modeling on the evaluation of experienced and imagined painful events, 173 healthy volunteers (96 women) completed the Prior Pain Experience Questionnaire, a 79-question assessment of the intensity of painful events, and a questionnaire regarding exposure to parental pain models. Consistent with existing literature, greater ratings of experienced pain were noted among Black vs. White participants. Parental pain modeling was associated with higher imagined pain ratings, but only when the parent matched the participant’s sex. This effect was greater among White and Asian participants than Black or Hispanic participants, implying ethno-cultural effects may moderate the influence of pain modeling on the evaluation of imagined pain events. The clinical implications of these findings, as well as the predictive ability of imagined pain ratings for determining future experiences of pain, should be investigated in future studies. PMID:26085306

  3. Experimental animal models of osteonecrosis.

    Science.gov (United States)

    Fan, Meng; Peng, Jiang; Qin, Ling; Lu, Shibi

    2011-08-01

    Osteonecrosis (ON) or avascular necrosis (AVN) is a common bone metabolic disorder, mostly affecting femoral head. Although many biological, biophysical, and surgical methods have been tested to preserve the femoral head with ON, none has been proven fully satisfactory. It lacks consensus on an optimal approach for treatment. This is due, at least in part, to the lack of ability to systematically compare treatment efficacy using an ideal animal model that mimics full-range osteonecrosis of femoral head (ONFH) in humans with high incidence of joint collapse accompanied by reparative reaction adjacent to the necrotic bone in a reproducible and accessible way. A number of preclinical animal ON models have been established for testing potential efficacy of various modalities developed for prevention and treatment of ON before introduction into clinics for potential applications. This paper describes a number of different methods for creating animal experimental ON models. Advantages and disadvantages of such models are also discussed as reference for future research in battle against this important medical condition.

  4. Ethnicity interacts with the OPRM1 gene in experimental pain sensitivity.

    Science.gov (United States)

    Hastie, Barbara A; Riley, Joseph L; Kaplan, Lee; Herrera, Dyanne G; Campbell, Claudia M; Virtusio, Kathrina; Mogil, Jeffrey S; Wallace, Margaret R; Fillingim, Roger B

    2012-08-01

    Robust interindividual variation in pain sensitivity has been observed, and recent evidence suggests that some of the variability may be genetically mediated. Our previous data revealed significantly higher pressure pain thresholds among individuals possessing the minor G allele of the A118G SNP of the mu-opioid receptor gene (OPRM1) compared with those with 2 consensus alleles. Moreover, ethnic differences in pain sensitivity have been widely reported. Yet, little is known about the potential interactive associations of ethnicity and genotype with pain perception. This study aimed to identify ethnic differences in OPRM1 allelic associations with experimental pain responses. A total of 247 healthy young adults from three ethnic groups (81 African Americans; 79 non-white Hispanics; and 87 non-Hispanic whites) underwent multiple experimental pain modalities (thermal, pressure, ischemic, cold pressor). Few African Americans (7.4%) expressed the rare allele of OPRM1 compared to non-Hispanic whites and Hispanics (28.7% vs. 27.8%, respectively). Across the entire sample, OPRM1 genotype did not significantly affect pain sensitivity. However, analysis in each ethnic group separately revealed significant genotype effects for most pain modalities among non-Hispanic-whites (P<.05) but not Hispanics or African Americans. The G allele was associated with decreased pain sensitivity among whites only; a trend in the opposite direction emerged in Hispanics. The reasons for this dichotomy are unclear; they may involve ethnic differences in haplotypic structure, or A118G may be a tag-SNP linked to other functional polymorphisms. These findings demonstrate an ethnicity-dependent association of OPRM1 genotype with pain sensitivity. Additional research is warranted to uncover the mechanisms influencing these relationships. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  5. Indirect Acquisition of Pain-Related Fear: An Experimental Study of Observational Learning Using Coloured Cold Metal Bars: e0117236

    National Research Council Canada - National Science Library

    Kim Helsen; Johan W S Vlaeyen; Liesbet Goubert

    2015-01-01

    .... The results of two experimental studies were presented, each with a different pain stimulus, of which the aim was to investigate the effect of observational learning on pain expectancies, avoidance...

  6. Indirect acquisition of pain-related fear: an experimental study of observational learning using coloured cold metal bars

    National Research Council Canada - National Science Library

    Helsen, K; Vlaeyen, J.W.S; Goubert, L

    2015-01-01

    .... The results of two experimental studies were presented, each with a different pain stimulus, of which the aim was to investigate the effect of observational learning on pain expectancies, avoidance...

  7. Reorganized Trunk Muscle Activity During Multidirectional Floor Perturbations After Experimental Low Back Pain: A Comparison of Bilateral Versus Unilateral Pain.

    Science.gov (United States)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2016-02-01

    Low back pain changes trunk muscle activity after external perturbations but the relationship between pain intensities and distributions and their effect on trunk muscle activity remains unclear. The effects of unilateral and bilateral experimental low back pain on trunk muscle activity were compared during unpredictable multidirectional surface perturbations in 19 healthy participants. Pain intensity and distribution were assessed using a visual analogue scale (VAS) and pain drawings. Root mean square (RMS) of the electromyographic (EMG) signals from 6 trunk muscles bilaterally after each perturbation was extracted and averaged across perturbations. The difference (ΔRMS-EMG) and absolute difference (absolute ΔRMS-EMG) RMS from baseline conditions were extracted for each muscle during pain conditions and averaged bilaterally for back and abdominal muscle groups. Bilateral compared with unilateral pain induced higher VAS scores (P pain areas (P pain (P back (P back (P pain. Bilateral pain caused greater absolute ΔRMS-EMG changes in the back (P pain. This study provided novel observations of differential trunk muscle activity in response to perturbations dependent on pain intensity and/or pain distribution. Because of complex and variable changes the relevance of clinical examination of muscle activity during postural tasks is challenged. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  8. Natural products assessed in animal models for orofacial pain – a systematic review

    Directory of Open Access Journals (Sweden)

    Pollyana S. Siqueira-Lima

    Full Text Available ABSTRACT Orofacial pain is related to tissues of the head, face, neck and all the intraoral structures; it is rather debilitating to the patient and also difficult to treat. There are relatively few studies dedicated to the use of natural products to alleviate orofacial pain in preclinical experiment models (performed in experimental animals which provide support for clinical trials. Main objectives of the present systematic review summarize the studies on natural products assessed in animal models for orofacial pain seeking to give evidence to future development of new pharmaceutical products to manage the orofacial pain. Our review includes a thorough search of literature using the terms of orofacial pain, facial pain, medicinal plants and natural products. This search was performed using to retrieve English language articles in Medline-PubMed, Scopus and Web of Science. A total of eighteen studies were included in our survey for the inclusion criteria. Firstly, this review identified 210 citations from electronic search, after removal of duplicates and screening for relevant titles and abstracts, a total of eighteen articles were selected to the inclusion criteria established. Our findings suggest that natural products can be a promising or a trump tool for the development of new drugs to treat orofacial pain conditions, but the researchers that deal with experimental preclinical trials of new drugs (including natural products or synthetic drugs for orofacial pain conditions urgently need to show translational evidence (with clinical approach of these compounds.

  9. Women with dysmenorrhoea are hypersensitive to experimentally induced forearm ischaemia during painful menstruation and during the pain-free follicular phase.

    Science.gov (United States)

    Iacovides, S; Avidon, I; Baker, F C

    2015-07-01

    Monthly primary dysmenorrhoeic pain is associated with increased sensitivity to painful stimuli, particularly in deep tissue. We investigated whether women with dysmenorrhoea, compared with controls, have increased sensitivity to experimentally induced deep-tissue muscle ischaemia in a body area distant from that of referred menstrual pain. The sub-maximal effort tourniquet test was used to induce forearm ischaemia in 11 women with severe dysmenorrhoea and in nine control women both during menstruation and in the follicular phase of the menstrual cycle. Von Frey hair assessments confirmed the presence of experimental ischaemia. Women rated the intensity of menstrual and ischaemic pain on a 100-mm visual analogue scale. Women with dysmenorrhoea [mean (SD): 68 (20) mm] reported significantly greater menstrual pain compared with controls [mean (SD): 2 (6) mm; p = 0.0001] during the menstruation phase. They also rated their forearm ischaemic pain as significantly greater than the controls during the menstruation [dysmenorrhoeics vs. controls mean (SD): 58 (19) mm vs. 31 (21) mm, p menstruation phase and pain-free follicular phase. These findings suggest the presence of long-lasting changes in muscle pain sensitivity in women with dysmenorrhoea. Our findings that dysmenorrhoeic women are hyperalgesic to a clinically relevant, deep-muscle ischaemic pain in areas outside of referred menstrual pain confirm other studies showing long-lasting changes in pain sensitivity outside of the painful period during menstruation. © 2014 European Pain Federation - EFIC®

  10. A quantitative review of ethnic group differences in experimental pain response: do biology, psychology, and culture matter?

    Science.gov (United States)

    Rahim-Williams, Bridgett; Riley, Joseph L; Williams, Ameenah K K; Fillingim, Roger B

    2012-04-01

    Pain is a subjectively complex and universal experience. We examine research investigating ethnic group differences in experimental pain response and factors contributing to group differences. We conducted a systematic literature review and analysis of studies using experimental pain stimuli to assess pain sensitivity across multiple ethnic groups. Our search covered the period from 1944 to 2011, and used the PubMed bibliographic database; a reference source containing over 17 million citations. We calculated effect sizes; identified ethnic/racial group categories, pain stimuli, and measures; and examined findings regarding biopsychosociocultural factors contributing to ethnic/racial group differences. We found 472 studies investigating ethnic group differences and pain. Twenty-six of these met our review inclusion criteria of investigating ethnic group differences in experimental pain. The majority of studies included comparisons between African Americans (AA) and non-Hispanic Whites (NHW). There were consistently moderate to large effect sizes for pain tolerance across multiple stimulus modalities; AA demonstrated lower pain tolerance. For pain threshold, findings were generally in the same direction, but effect sizes were small to moderate across ethnic groups. Limited data were available for suprathreshold pain ratings. A subset of studies comparing NHW and other ethnic groups showed a variable range of effect sizes for pain threshold and tolerance. There are potentially important ethnic/racial group differences in experimental pain perception. Elucidating ethnic group differences has translational merit for culturally competent clinical care and for addressing and reducing pain treatment disparities among ethnically/racially diverse groups. Wiley Periodicals, Inc.

  11. Effects of Anethole in Nociception Experimental Models

    Directory of Open Access Journals (Sweden)

    Alessandra Mileni Versuti Ritter

    2014-01-01

    Full Text Available This study investigated the antinociceptive activity of anethole (anethole 1-methoxy-4-benzene (1-propenyl, major compound of the essential oil of star anise (Illicium verum, in different experimental models of nociception. The animals were pretreated with anethole (62.5, 125, 250, and 500 mg/kg one hour before the experiments. To eliminate a possible sedative effect of anethole, the open field test was conducted. Anethole (62.5, 125, 250, and 500 mg/kg showed an antinociceptive effect in the writhing model induced by acetic acid, in the second phase of the formalin test (125 and 250 mg/kg in the test of glutamate (62.5, 125, and 250 mg/kg, and expresses pain induced by ACF (250 mg/kg. In contrast, anethole was not able to increase the latency time on the hot plate and decrease the number of flinches during the initial phase of the formalin test in any of the doses tested. It was also demonstrated that anethole has no association with sedative effects. Therefore, these data showed that anethole, at all used doses, has no sedative effect and has an antinociceptive effect. This effect may be due to a decrease in the production/release of inflammatory mediators.

  12. Evaluation of anti-hyperalgesic and analgesic effects of two benzodiazepines in human experimental pain: a randomized placebo-controlled study.

    Directory of Open Access Journals (Sweden)

    Pascal H Vuilleumier

    Full Text Available Compounds that act on GABA-receptors produce anti-hyperalgesia in animal models, but little is known on their effects in humans. The aim of this study was to explore the potential usefulness of GABA-agonism for the control of pain in humans. Two agonists at the benzodiazepine-binding site of GABAA-receptors (clobazam and clonazepam were studied using multiple experimental pain tests. Positive results would support further investigation of GABA agonism for the control of clinical pain.In a randomized double-blind crossover design, 16 healthy male volunteers received clobazam 20 mg, clonazepam 1 mg and tolterodine 1 mg (active placebo. The area of static hyperalgesia after intradermal capsaicin injection was the primary endpoint. Secondary endpoints were: area of dynamic hyperalgesia, response to von Frey hair stimulation, pressure pain thresholds, conditioned pain modulation, cutaneous and intramuscular electrical pain thresholds (1, 5 and 20 repeated stimulation, and pain during cuff algometry.For the primary endpoint, an increase in the area of static hyperalgesia was observed after administration of placebo (p<0.001, but not after clobazam and clonazepam. Results suggestive for an anti-hyperalgesic effect of the benzodiazepines were obtained with all three intramuscular pain models and with cuff algometry. No effect could be detected with the other pain models employed.Collectively, the results are suggestive for a possible anti-hyperalgesic effect of drugs acting at the GABAA-receptors in humans, particularly in models of secondary hyperalgesia and deep pain. The findings are not conclusive, but support further clinical research on pain modulation by GABAergic drugs. Because of the partial results, future research should focus on compounds acting selectively on subunits of the GABA complex, which may allow the achievement of higher receptor occupancy than unselective drugs. Our data also provide information on the most suitable experimental

  13. Evaluation of Anti-Hyperalgesic and Analgesic Effects of Two Benzodiazepines in Human Experimental Pain: A Randomized Placebo-Controlled Study

    Science.gov (United States)

    Vuilleumier, Pascal H.; Besson, Marie; Desmeules, Jules; Arendt-Nielsen, Lars; Curatolo, Michele

    2013-01-01

    Background and Aims Compounds that act on GABA-receptors produce anti-hyperalgesia in animal models, but little is known on their effects in humans. The aim of this study was to explore the potential usefulness of GABA-agonism for the control of pain in humans. Two agonists at the benzodiazepine-binding site of GABAA-receptors (clobazam and clonazepam) were studied using multiple experimental pain tests. Positive results would support further investigation of GABA agonism for the control of clinical pain. Methods In a randomized double-blind crossover design, 16 healthy male volunteers received clobazam 20 mg, clonazepam 1 mg and tolterodine 1 mg (active placebo). The area of static hyperalgesia after intradermal capsaicin injection was the primary endpoint. Secondary endpoints were: area of dynamic hyperalgesia, response to von Frey hair stimulation, pressure pain thresholds, conditioned pain modulation, cutaneous and intramuscular electrical pain thresholds (1, 5 and 20 repeated stimulation), and pain during cuff algometry. Results For the primary endpoint, an increase in the area of static hyperalgesia was observed after administration of placebo (pbenzodiazepines were obtained with all three intramuscular pain models and with cuff algometry. No effect could be detected with the other pain models employed. Conclusions Collectively, the results are suggestive for a possible anti-hyperalgesic effect of drugs acting at the GABAA-receptors in humans, particularly in models of secondary hyperalgesia and deep pain. The findings are not conclusive, but support further clinical research on pain modulation by GABAergic drugs. Because of the partial results, future research should focus on compounds acting selectively on subunits of the GABA complex, which may allow the achievement of higher receptor occupancy than unselective drugs. Our data also provide information on the most suitable experimental models for future investigation of GABAergic compounds. Trial

  14. Comparison of acceptance and distraction strategies in coping with experimentally induced pain

    Directory of Open Access Journals (Sweden)

    Moore H

    2015-03-01

    Full Text Available Hazel Moore,1 Ian Stewart,1 Dermot Barnes-Holmes,2 Yvonne Barnes-Holmes,2 Brian E McGuire1,31School of Psychology, National University of Ireland, Galway, 2Department of Psychology, National University of Ireland, Maynooth, 3Centre for Pain Research, National University of Ireland, Galway, IrelandBackground: This study compared an acceptance-based strategy with a control-based strategy (distraction in terms of the ability of participants to tolerate a painful stimulus, across two experiments. In addition, participants were either actively encouraged, or not, to link pain tolerance with pursuit of valued goals to examine the impact of pursuing a personally meaningful goal or value on the extent to which pain will be tolerated.Methods: Participants in experiment 1 (n=41 and experiment 2 (n=52 were equally assigned to acceptance or distraction protocols. Further, half the participants in each group generated examples from their own lives in which they had pursued a valued objective, while the other half did not. In experiment 2, the values focus was enhanced to examine the impact on pain tolerance.Results: There were no significant differences overall between the acceptance and distraction groups on pain tolerance in either experiment. However, in experiment 2, individuals classified as accepting in terms of general coping style and who were assigned to the acceptance strategy showed significantly better pain tolerance than accepting individuals who were in the distraction condition. Across both experiments, those with strong goal-driven values in both protocols were more tolerant of pain. Participants appeared to have more difficulty adhering to acceptance than to distraction as a strategy.Conclusion: Acceptance may be associated with better tolerance of pain, but may also be more difficult to operationalize than distraction in experimental studies. Matching coping style and coping strategy may be most effective, and enhancement of goal

  15. Experimental muscle pain challenges the postural stability during quiet stance and unexpected posture perturbation.

    Science.gov (United States)

    Hirata, Rogério Pessoto; Ervilha, Ulysses Fernandes; Arendt-Nielsen, Lars; Graven-Nielsen, Thomas

    2011-08-01

    Musculoskeletal pain impairs postural control and stability. Nine subjects stood as quietly as possible on a moveable force platform before, during, and after experimental pain in the right leg muscles. A moveable force platform was used to measure the center of pressure and provided unexpected perturbations. Lower limb muscle activity, joint angles, and foot pressure distributions were measured. Hypertonic saline was used to induce pain in the vastus lateralis, vastus medialis, or biceps femoris muscle of the right leg. Compared to baseline and control sessions, pain in the knee extensor muscles during quiet standing evoked: 1) larger sway area, greater medial-lateral center of pressure displacement and higher speed (P increased sway displacement in the anterior-posterior direction (P increased electromyography (EMG) activity for left tibialis anterior and left erector spinae muscles (P < .05). Pain provoked longer time to return to an equilibrium posture after forward EMG activity for, and pain in vastus medialis muscle decreased the time for the maximum hip flexion during this perturbation (P < .05). These results show that muscle pain impairs postural stability during quiet standing and after unexpected perturbation, which suggest that people suffering from leg muscle pain are more vulnerable to falls. This article presents the acute responses to leg muscle pain on the postural control. This measure could potentially help clinicians who seek to assess how pain responses may contribute to patient's postural control and stability during quiet standing and after recovering from unexpected perturbations. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  16. Descending facilitatory pain pathways mediate ongoing pain and tactile hypersensitivity in a rat model of trigeminal neuropathic pain.

    Science.gov (United States)

    Nones, C F M; Claudino, R F; Ferreira, L E N; Dos Reis, R C; King, T; Chichorro, J G

    2017-03-22

    The Chronic Constriction Injury of the Infraorbital Nerve (CCI-ION) is a well-established model to study facial sensory changes related to trigeminal neuropathic pain. CCI-ION induces heat hypersensitivity that resolves within 2-3 weeks and a delayed mechanical hypersensitivity that emerges during the second week post-injury. The role of descending facilitatory pain pathways from the rostro ventromedial medulla (RVM) in mediating the heat and tactile hypersensitivity was examined. CCI-ION induced heat hypersensitivity observed 5days post-surgery was reversed by systemic, but not RVM lidocaine. CCI-ION-induced tactile hypersensitivity observed 15days post-surgery was reversed by systemic lidocaine and attenuated by RVM lidocaine. CCI-ION-induced spontaneous pain was determined using conditioned place preference (CPP) to pain relief at each time-point. At day 5 post-CCI-ION, neither systemic nor RVM lidocaine induced CPP. However, at 15days post-CCI-ION, CPP was observed to the chamber paired with RVM lidocaine, but not systemic lidocaine. These data indicate that CCI-ION induced heat hypersensitivity is not dependent on descending facilitatory pain pathways 5-days post-injury whereas descending facilitatory pain pathways mediate tactile allodynia and spontaneous pain 15days post-CCI-ION. This suggests that CCI-ION induces early peripheral sensitization followed by development of central sensitization that mediates spontaneous pain and contributes to mechanical hypersensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Changes in pain catastrophizing predict later changes in fibromyalgia clinical and experimental pain report: cross-lagged panel analyses of dispositional and situational catastrophizing.

    Science.gov (United States)

    Campbell, Claudia M; McCauley, Lea; Bounds, Sara C; Mathur, Vani A; Conn, Lora; Simango, Mpepera; Edwards, Robert R; Fontaine, Kevin R

    2012-10-25

    Fibromyalgia (FM), characterized by wide-spread diffuse pain and sensory abnormalities, is associated with elevated indices of distress and pain-related catastrophizing compared to both pain-free samples and those with chronic pain conditions. Catastrophizing is a pervasive negative mental set, and is a strong predictor of negative pain-related outcomes such as clinical pain intensity, and physical disability. Situational catastrophizing, measured in the context of experimentally-induced pain, is strongly related to enhanced pain sensitivity, a core aspect of the pathophysiology of fibromyalgia. However, little is known regarding the temporal course of the association between catastrophizing and pain-related "outcomes". Most studies involve only static assessments of pain and catastrophizing at a single time point, which provides little insight into the direction of the observed associations. We sought to investigate the temporal relationships between catastrophizing and indices of both clinical pain (substudy 1) and experimentally-induced pain (substudy 2) in a larger randomized controlled longitudinal trial. Fifty-seven patients with FM completed catastrophizing, depression, and pain questionnaires as well as laboratory cold pressor pain testing at baseline, post-intervention and three month follow-up during a lifestyle physical activity study. Cross-lagged panel analyses were used to address these temporal relationships. In substudy 1, analyses revealed that pre-to-post changes in dispositional catastrophizing ratings prospectively accounted for unique variance in subsequent post-to-follow-up changes in clinical pain ratings (p = 0.005), while pre-to-post changes in pain ratings did not account for unique variance in post-to-follow-up changes in catastrophizing ratings. An identical pattern was observed experimentally in substudy 2, with pre-to-post changes in situational catastrophizing ratings prospectively accounting for unique variance in subsequent post

  18. Historical development of epistemology and the study of pain: Place of neuromodulation of electroacupuncture in the experimental pain research

    Directory of Open Access Journals (Sweden)

    Bárbara B. Garrido-Suárez

    2013-10-01

    Full Text Available Despite the diffusion of acupuncture and its related techniques in Cuba and the World, its mechanism of action is still controversial, being considered by the most sceptics as placebo or some kind oriental myth, and it only should by related to this subjects as a matter of cultural-historical elements and not to science. The purpose of this revision is to characterize the pain sensation, after a critical analysis of the different philosophical streams related to the human knowledge and its expression in the historical evolution of the algology. On the other hand, to emphasize the importance of electroacupuncture-induced neuro-modulation in the field of experimental pain researches. In this content will be analyzed the concept of Khun paradigm and his ideas about the structure of scientific revolution in the theory of gates control and the explosion of pain researches in the last decades. It will related the introduction to acupuncture and its techniques in pain clinics, with scientific context of the historical moment. In addition, a space will be dedicated to the topic of complementary and alternative medicine on the century of evidence based medicine, given its scientific needs of validation in ours times.

  19. Pain medicine and its models: helping or hindering?

    Science.gov (United States)

    Quintner, John L; Cohen, Milton L; Buchanan, David; Katz, James D; Williamson, Owen D

    2008-10-01

    To identify whether the biopsychosocial framework of illness has overcome the limitations of the biomedical model of disease when applied in the practice of pain medicine. Critical review of the literature concerning the application of biopsychosocial models to the praxis of pain medicine and the concepts of living systems. The biopsychosocial model of illness, formulated by Engel in 1977, has generated the International Association for the Study of Pain (IASP) definition of pain, two major conceptual frameworks in pain medicine, and three putative explanatory models for pain. However, in the absence of a theory that seeks to understand the lived experience of pain as an emergent and unpredictable phenomenon, these progeny of the biopsychosocial model have been caught in circular argument and have been unable to overcome biomedical reductionism or the perpetuation of body-mind dualism. In particular, the implication that pain can be a "thing" separate and distinct from the body bears little relationship to the lived experience of pain. Such marginalizing results when an observer attempts to reduce the experience of the pain of another person. The self-referentiality of living systems (through their qualities of autopoiesis, noncentrality and negentropy) sees pain "emerge" in unpredictable ways that defy any lineal reduction of the lived experience to any particular "thing." Pain therefore constitutes an aporia, a space and presence that defies us access to its secrets. We suggest a project in which pain may be apprehended in the clinical encounter, through the engagement of two autonomous self-referential beings in the intersubjective or so-called third space, from which new therapeutic possibilities can arise.

  20. The effect of spinal manipulative therapy on experimentally induced pain: a systematic literature review

    Directory of Open Access Journals (Sweden)

    Millan Mario

    2012-08-01

    Full Text Available Abstract Background Although there is evidence that spinal manipulative therapy (SMT can reduce pain, the mechanisms involved are not well established. There is a need to review the scientific literature to establish the evidence-base for the reduction of pain following SMT. Objectives To determine if SMT can reduce experimentally induced pain, and if so, if the effect is i only at the level of the treated spinal segment, ii broader but in the same general region as SMT is performed, or iii systemic. Design A systematic critical literature review. Methods A systematic search was performed for experimental studies on healthy volunteers and people without chronic syndromes, in which the immediate effect of SMT was tested. Articles selected were reviewed blindly by two authors. A summary quality score was calculated to indicate level of manuscript quality. Outcome was considered positive if the pain-reducing effect was statistically significant. Separate evidence tables were constructed with information relevant to each research question. Results were interpreted taking into account their manuscript quality. Results Twenty-two articles were included, describing 43 experiments, primarily on pain produced by pressure (n = 27 or temperature (n = 9. Their quality was generally moderate. A hypoalgesic effect was shown in 19/27 experiments on pressure pain, produced by pressure in 3/9 on pain produced by temperature and in 6/7 tests on pain induced by other measures. Second pain provoked by temperature seems to respond to SMT but not first pain. Most studies revealed a local or regional hypoalgesic effect whereas a systematic effect was unclear. Manipulation of a “restricted motion segment” (“manipulable lesion” seemed not to be essential to analgesia. In relation to outcome, there was no discernible difference between studies with higher vs. lower quality scores. Conclusions These results indicate that SMT has a direct local

  1. The effect of spinal manipulative therapy on experimentally induced pain: a systematic literature review

    Science.gov (United States)

    2012-01-01

    Background Although there is evidence that spinal manipulative therapy (SMT) can reduce pain, the mechanisms involved are not well established. There is a need to review the scientific literature to establish the evidence-base for the reduction of pain following SMT. Objectives To determine if SMT can reduce experimentally induced pain, and if so, if the effect is i) only at the level of the treated spinal segment, ii) broader but in the same general region as SMT is performed, or iii) systemic. Design A systematic critical literature review. Methods A systematic search was performed for experimental studies on healthy volunteers and people without chronic syndromes, in which the immediate effect of SMT was tested. Articles selected were reviewed blindly by two authors. A summary quality score was calculated to indicate level of manuscript quality. Outcome was considered positive if the pain-reducing effect was statistically significant. Separate evidence tables were constructed with information relevant to each research question. Results were interpreted taking into account their manuscript quality. Results Twenty-two articles were included, describing 43 experiments, primarily on pain produced by pressure (n = 27) or temperature (n = 9). Their quality was generally moderate. A hypoalgesic effect was shown in 19/27 experiments on pressure pain, produced by pressure in 3/9 on pain produced by temperature and in 6/7 tests on pain induced by other measures. Second pain provoked by temperature seems to respond to SMT but not first pain. Most studies revealed a local or regional hypoalgesic effect whereas a systematic effect was unclear. Manipulation of a “restricted motion segment” (“manipulable lesion”) seemed not to be essential to analgesia. In relation to outcome, there was no discernible difference between studies with higher vs. lower quality scores. Conclusions These results indicate that SMT has a direct local/regional hypoalgesic effect on

  2. An overview of animal models of pain: disease models and outcome measures

    Science.gov (United States)

    Gregory, N; Harris, AL; Robinson, CR; Dougherty, PM; Fuchs, PN; Sluka, KA

    2013-01-01

    Pain is ultimately a perceptual phenomenon. It is built from information gathered by specialized pain receptors in tissue, modified by spinal and supraspinal mechanisms, and integrated into a discrete sensory experience with an emotional valence in the brain. Because of this, studying intact animals allows the multidimensional nature of pain to be examined. A number of animal models have been developed, reflecting observations that pain phenotypes are mediated by distinct mechanisms. Animal models of pain are designed to mimic distinct clinical diseases to better evaluate underlying mechanisms and potential treatments. Outcome measures are designed to measure multiple parts of the pain experience including reflexive hyperalgesia measures, sensory and affective dimensions of pain and impact of pain on function and quality of life. In this review we discuss the common methods used for inducing each of the pain phenotypes related to clinical pain syndromes, as well as the main behavioral tests for assessing pain in each model. PMID:24035349

  3. PAIN IN A PARKINSON`S DISEASE RODENT ANIMAL MODEL INDUCED WITH 6-HYDROXYDOPAMINE

    Directory of Open Access Journals (Sweden)

    Antioch, I

    2017-06-01

    Full Text Available Pain phenomenon, the unpleasant sensory and emotional event, appears to evidently intrude in Parkinson disease (PD, a disease formally considered to be restricted only to motor deficits. Although over a half of persons with PD suffer from pain manifestations, there are very few reports targeting this issue. Considering the cases when motor symptoms of PD are eclipsed by severe pain disclosure, there is an obvious need of clarifying the intricate implications of pain in PD context. Because there are few studies researching the link between pain and PD in clinical context, but as well in animal models we chose to explore the effects of pain stimuli on a rodent model of PD. Materials and methods: We experimentally induced a PD model in Wistar rats (n=12 by injecting in the substantia nigra, a brain area known to be involved in PD occurrence, one dose of a 6-hydroxidopamine (6-OHDA solution (8µm 6-OHDA base and 4µm physiological saline, utilizing neurosurgery, while their control peers received same dose of saline solution. Two weeks after the intervention the animals were subjected to the hot-plate test, a behavioral task for acquiring pain sensitivity. Results: There was noticed a statistical significant (F(1,10 = 5.67, p=0.038 sensibility of the 6-OHDA rats to thermal pain stimuli (8.2 s ± 0.8 s in 6-OHDA group as compared to their peers (13.8 s ± 1.6 s in controls. Conclusions: The involvement of pain in PD animal models is demonstrated raising questions of how it influences PD evolution. Moreover, this result increases awareness of deficient diagnostic methods of pain in PD and as a consequence, poor treatment of pain manifestations.

  4. Using an experimental model for the study of therapeutic touch.

    Science.gov (United States)

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  5. Pain, aging and dementia: Towards a biopsychosocial model.

    Science.gov (United States)

    Gagliese, Lucia; Gauthier, Lynn R; Narain, Nadine; Freedman, Tamlyn

    2017-09-22

    Dementia is a progressive disease associated with irreversible impairment and loss of cognitive abilities. About half of older people with dementia experience pain. In this paper, we propose that pain in older people with dementia can be conceptualized as the final result of the interaction of three heterogeneous phenomena, pain, aging, and dementia, which are created and influenced by the interactions of predisposing, lifelong, and current biopsychosocial factors. We review pain assessment in people with dementia using both self-report and observational/behavioral measures. We then review the biological/sensory, psychological (cognitive and affective) and social dimensions of pain in dementia. The available data suggest that dementia does not impact pain threshold or tolerance. To date, there is little research on the social dimension of pain in dementia. Changes in the affective domain in response to experimental pain have been contradictory with evidence supporting both increased and decreased unpleasantness and emotional responsiveness in people with dementia compared to healthy controls. Clinically, depression is a significant burden for older people with dementia and chronic pain. The relationship between pain and other neuropsychiatric symptoms is controversial, and there is insufficient evidence on which to base conclusions. Some of the most important dementia-related changes may arise in the cognitive domain, including impairments of semantic and episodic memory for pain, executive function, and pain anticipation. Changes in brain activation and interconnectivity support many of these conclusions. Despite methodological limitations, we conclude there are compelling preliminary data to support a biopsychosocial framework of pain and dementia. Future research directions, especially the need for improved assessment tools, are highlighted. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Effects of interferential therapy parameter combinations upon experimentally induced pain in pain-free participants: a randomized controlled trial.

    Science.gov (United States)

    Dounavi, Myrto D; Chesterton, Linda S; Sim, Julius

    2012-07-01

    Little evidence exists regarding parameter selection for hypoalgesia using interferential therapy (IFT). This study investigated segmental and extrasegmental hypoalgesic effects of different IFT parameter combinations upon experimentally induced pressure pain threshold (PPT) in pain-free volunteers. The participants were randomly assigned to 6 groups: control, placebo, bipolar constant amplitude modulation frequency (AMF), bipolar sweep AMF, quadripolar constant AMF, and quadripolar sweep AMF. The study was conducted in a university laboratory. One hundred eighty adults who were healthy and pain-free participated in the study. Interferential therapy was delivered to all groups at high, to-tolerance intensity and at high AMF. Stimulation to the dominant forearm was delivered for 30 minutes, with monitoring for a further 30 minutes. Pain pressure threshold was measured at the area of first dorsal interosseous muscle of the dominant and nondominant hands (segmental measurements) and over the tibialis anterior muscle (extrasegmental measurement) at baseline and at 10-minute intervals using a pressure algometer. Square root transformed PPT data were analyzed using repeated-measures analysis of variance. There was a significant change in PPT over time, but no significant between-subjects difference in segmental or extrasegmental PPT between any of the IFT groups and the placebo or control group. Thus, IFT delivered in any of these parameter combinations did not significantly affect the PPT of pain-free participants compared with the control or placebo group. Success of blinding was not evaluated. This study showed that IFT delivered at high, to-tolerance intensity and high AMF does not produce significant segmental and extrasegmental hypoalgesic effects on PPT in participants who were healthy compared with a control or placebo group. Further research is warranted to investigate the hypoalgesic effect of different IFT parameter combinations and to explain its possible

  7. The effects of experimental knee pain on lower limb corticospinal and motor cortex excitability.

    Science.gov (United States)

    Rice, David Andrew; Graven-Nielsen, Thomas; Lewis, Gwyn Nancy; McNair, Peter John; Dalbeth, Nicola

    2015-08-12

    Notable weakness of the quadriceps muscles is typically observed as a consequence of knee joint arthritis, knee surgery and knee injury. This is partly due to ongoing neural inhibition that prevents the central nervous system from fully activating the quadriceps, a process known as arthrogenic muscle inhibition (AMI). To investigate the mechanisms underlying AMI, this study explored the effects of experimental knee pain on lower limb corticospinal and motor cortex excitability. Twenty-four healthy volunteers participated in this study. In experiment 1, experimental knee pain was induced by the injection of hypertonic saline into the infrapatellar fat pad (n = 18). In experiment 2, isotonic saline was injected into the fat pad as a non-painful control (n = 8). Pain intensity was measured on a 10-cm electronic visual analogue scale. Transcranial magnetic stimulation and electromyography were used to measure lower limb motor-evoked potential amplitude and short-interval intracortical inhibition before and after the injection. The peak VAS score following hypertonic saline (5.0 ± 0.5 cm) was higher than after isotonic saline (p 0.05). There was no change in short-interval intracortical inhibition measured from vastus lateralis following injection (both p >0.05). Quadriceps corticospinal excitability increases during experimental knee pain, providing no evidence for a supraspinal contribution to quadriceps AMI.

  8. Who can benefit from virtual reality to reduce experimental pain? A crossover study in healthy subjects.

    Science.gov (United States)

    Demeter, N; Josman, N; Eisenberg, E; Pud, D

    2015-11-01

    The present study aimed to identify predicting factors affecting experimental pain stimuli reduction by using 'EyeToy', which is an Immersive Virtual Reality System (IVRS). Sixty-two healthy subjects (31 M, 31 F) underwent a battery of pain tests to determine each participant's baseline sensitivity to nociceptive. The battery included thermal pain tests (hot and cold) as well as a paradigm to induce conditioned pain modulation (CPM). Later on, each subject participated in two study conditions in random order: (1) An exposure to tonic heat stimulation (46.5 °C/135 s) to the ankle while participating in VR environment which included an activity requiring limb movements; (2) Same heat stimulation with no exposure to VR. Six pain measures were taken during each study condition (baseline, test 1-5). An interaction of time × treatment was found (RM ANOVA, F(5, 305)  = 24.33, p manipulation for pain reduction in individuals with efficient CPM and in women. These findings constitute a promising platform for future research and hold potential for the improvement and facilitation of clinical treatment. © 2015 European Pain Federation - EFIC®

  9. Complex muscular adaptation to perturbations after induction of experimental low back pain in healthy participants

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2014-01-01

    Background and aims Spine stability is affected in low back (LB) pain and potentially by muscle fatigue and soreness. This study assessed motor control responses to unexpected surface perturbations during stance during experimental LB muscle pain combined with fatigue and muscle soreness. Methods...... Nineteen healthy participants were examined day 1-3 before and after bilateral injections of hypertonic saline into m. longissimus. Pain intensity was scored on a visual analogue scale (VAS). Day 2 included injections during post-exercise LB muscle fatigue and day 3 during delayed onset back muscle......RMSabs) in the RMS-EMG from the baseline of the day were calculated and averaged among back and abdominal muscles. Results VAS scores during fatigue and DOMS were significantly higher compared with day-1 (PBack muscle RMS-EMG decreased and abdominal muscle RMS-EMG increased during DOMS, compared with pain...

  10. Ghosts in the Machine. Interoceptive Modeling for Chronic Pain Treatment.

    Science.gov (United States)

    Di Lernia, Daniele; Serino, Silvia; Cipresso, Pietro; Riva, Giuseppe

    2016-01-01

    Pain is a complex and multidimensional perception, embodied in our daily experiences through interoceptive appraisal processes. The article reviews the recent literature about interoception along with predictive coding theories and tries to explain a missing link between the sense of the physiological condition of the entire body and the perception of pain in chronic conditions, which are characterized by interoceptive deficits. Understanding chronic pain from an interoceptive point of view allows us to better comprehend the multidimensional nature of this specific organic information, integrating the input of several sources from Gifford's Mature Organism Model to Melzack's neuromatrix. The article proposes the concept of residual interoceptive images (ghosts), to explain the diffuse multilevel nature of chronic pain perceptions. Lastly, we introduce a treatment concept, forged upon the possibility to modify the interoceptive chronic representation of pain through external input in a process that we call interoceptive modeling, with the ultimate goal of reducing pain in chronic subjects.

  11. Effects of experimental muscle pain on force variability during task-related and three directional isometric force task

    DEFF Research Database (Denmark)

    Mista, Christian Ariel; Graven-Nielsen, Thomas

    2013-01-01

    Experimentally muscle pain induces changes in the distribution of muscle activity and affects the muscle coordination. The force steadiness is impaired during muscle pain in the task-related force direction as well as in the tangential directions. In addition, pain lead to a mismatch between the ...

  12. Rethinking the Psychogenic Model of Complex Regional Pain Syndrome: Somatoform Disorders and Complex Regional Pain Syndrome

    OpenAIRE

    Hill, Renee J.; Chopra, Pradeep; Richardi, Toni

    2012-01-01

    Abstract Explaining the etiology of Complex Regional Pain Syndrome (CRPS) from the psychogenic model is exceedingly unsophisticated, because neurocognitive deficits, neuroanatomical abnormalities, and distortions in cognitive mapping are features of CRPS pathology. More importantly, many people who have developed CRPS have no history of mental illness. The psychogenic model offers comfort to physicians and mental health practitioners (MHPs) who have difficulty understanding pain maintained by...

  13. Pain Energy Model of Mobility Limitation in the Older Adult.

    Science.gov (United States)

    Coyle, Peter C; Schrack, Jennifer A; Hicks, Gregory E

    2017-05-22

    Chronic pain is prevalent, costly, and disabling among older adults. Although mobility decline is inevitable with aging, it is clear, from current evidence, that older adults with chronic pain experience a greater rate of functional mobility decline than their pain-free peers. Past studies suggest that pain expedites the age-related decline in functional mobility; however, the pathways through which pain affects mobility remain unclear. Gerontological experts hypothesize that the age-related decline in mobility may be driven by alterations in energy expenditure; these concepts are outlined in a model known as the Energetic Pathway of Mobility Loss. Pain may play a critical role in this process through a pathway of energetic inefficiency, physical inactivity, and decreased capacity.  The purposes of this article are to 1) summarize the current literature that supports the Energetic Pathway of Mobility Loss model and 2) propose a new framework, known as the Pain Energy Model, to clarify how the disablement process may be amplified among older adults with painful conditions.  This new framework is designed to generate new clinical research and to suggest new clinical implications for older adults with painful conditions by identifying key steps and potential treatment targets in the pathway to functional mobility decline.

  14. Omega-Conotoxins as Experimental Tools and Therapeutics in Pain Management

    Directory of Open Access Journals (Sweden)

    Heidi E. Hannon

    2013-03-01

    Full Text Available Neuropathic pain afflicts a large percentage of the global population. This form of chronic, intractable pain arises when the peripheral or central nervous systems are damaged, either directly by lesion or indirectly through disease. The comorbidity of neuropathic pain with other diseases, including diabetes, cancer, and AIDS, contributes to a complex pathogenesis and symptom profile. Because most patients present with neuropathic pain refractory to current first-line therapeutics, pharmaceuticals with greater efficacy in pain management are highly desired. In this review we discuss the growing application of ω-conotoxins, small peptides isolated from Conus species, in the management of neuropathic pain. These toxins are synthesized by predatory cone snails as a component of paralytic venoms. The potency and selectivity with which ω-conotoxins inhibit their molecular targets, voltage-gated Ca2+ channels, is advantageous in the treatment of neuropathic pain states, in which Ca2+ channel activity is characteristically aberrant. Although ω-conotoxins demonstrate analgesic efficacy in animal models of neuropathic pain and in human clinical trials, there remains a critical need to improve the convenience of peptide drug delivery methods, and reduce the number and severity of adverse effects associated with ω-conotoxin-based therapies.

  15. Omega-Conotoxins as Experimental Tools and Therapeutics in Pain Management

    Science.gov (United States)

    Hannon, Heidi E.; Atchison, William D.

    2013-01-01

    Neuropathic pain afflicts a large percentage of the global population. This form of chronic, intractable pain arises when the peripheral or central nervous systems are damaged, either directly by lesion or indirectly through disease. The comorbidity of neuropathic pain with other diseases, including diabetes, cancer, and AIDS, contributes to a complex pathogenesis and symptom profile. Because most patients present with neuropathic pain refractory to current first-line therapeutics, pharmaceuticals with greater efficacy in pain management are highly desired. In this review we discuss the growing application of ω-conotoxins, small peptides isolated from Conus species, in the management of neuropathic pain. These toxins are synthesized by predatory cone snails as a component of paralytic venoms. The potency and selectivity with which ω-conotoxins inhibit their molecular targets, voltage-gated Ca2+ channels, is advantageous in the treatment of neuropathic pain states, in which Ca2+ channel activity is characteristically aberrant. Although ω-conotoxins demonstrate analgesic efficacy in animal models of neuropathic pain and in human clinical trials, there remains a critical need to improve the convenience of peptide drug delivery methods, and reduce the number and severity of adverse effects associated with ω-conotoxin-based therapies. PMID:23470283

  16. Effects of unilateral and bilateral experimental low back pain on trunk muscle activity during stair walking in healthy and recurrent low back pain patients

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    Aim To explore the trunk muscle activity in healthy and recurrent low back pain (R-LBP) patients with no present pain during stair ascent and descent before and after unilateral and bilateral experimental low back pain (LBP). Methods Twenty-five healthy controls and 25 pain-free R-LBP patients...... in m. rectus abdominis during all phases, with larger decrease during bilateral compared with unilateral pain (Ppain in the back muscles (P....04). Conclusions The impact of unilateral and bilateral experimental LBP on trunk muscle activity was different between healthy participants and R-LBP patients. Pain resulted in increased trunk muscle activity in healthy, while R-LBP patients decreased the back and increased the abdominal muscle activity. However...

  17. The effect of experimental low back pain on lumbar muscle activity in people with a history of clinical low back pain: a muscle functional MRI study.

    Science.gov (United States)

    Danneels, Lieven; Cagnie, Barbara; D'hooge, Roseline; De Deene, Yves; Crombez, Geert; Vanderstraeten, Guy; Parlevliet, Thierry; Van Oosterwijck, Jessica

    2016-02-01

    In people with a history of low back pain (LBP), structural and functional alterations have been observed at several peripheral and central levels of the sensorimotor pathway. These existing alterations might interact with the way the sensorimotor system responds to pain. We examined this assumption by evaluating the lumbar motor responses to experimental nociceptive input of 15 participants during remission of unilateral recurrent LBP. Quantitative T2 images (muscle functional MRI) were taken bilaterally of multifidus, erector spinae, and psoas at several segmental levels (L3 upper and L4 upper and lower endplate) and during several conditions: 1) at rest, 2) upon trunk-extension exercise without pain, and 3) upon trunk-extension exercise with experimental induced pain at the clinical pain-side (1.5-ml intramuscular hypertonic saline injections in erector spinae). Following experimental pain induction, muscle activity levels similarly reduced for all three muscles, on both painful and nonpainful sides, and at multiple segmental levels (P = 0.038). Pain intensity and localization from experimental LBP were similar as during recalled clinical LBP episodes. In conclusion, unilateral and unisegmental experimental LBP exerts a generalized and widespread decrease in lumbar muscle activity during remission of recurrent LBP. This muscle response is consistent with previous observed patterns in healthy people subjected to the same experimental pain paradigm. It is striking that similar inhibitory patterns in response to pain could be observed, despite the presence of preexisting alterations in the lumbar musculature during remission of recurrent LBP. These results suggest that motor output can modify along the course of recurrent LBP. Copyright © 2016 the American Physiological Society.

  18. Analgesic Effect of Xenon in Rat Model of Inflammatory Pain.

    Science.gov (United States)

    Kukushkin, M L; Igon'kina, S I; Potapov, S V; Potapov, A V

    2017-02-01

    The analgesic effects of inert gas xenon were examined on rats. The formalin model of inflammatory pain, tail-flick test, and hot-plate test revealed the antinociceptive effects of subanesthetizing doses of inhalation anesthetic xenon. Inhalation of 50/50 xenon/oxygen mixture moderated the nociceptive responses during acute and tonic phases of inflammatory pain.

  19. Chronic pain: Model of psychosomatic disorder (review

    Directory of Open Access Journals (Sweden)

    Chernus N.P.

    2011-12-01

    Full Text Available The article presents a detailed review on epidemiology, pathogenesis and interrelation of serotonin neuromedia-tor metabolism in the central nervous system in state of chronic pain and depression. It has been demonstrated that neurophysiological conditions serve as psychological defense of an individual. That mechanism has been proved to «transform» serious emotions onto the inner level (body and it assists in the development of psychosomatic disorders — chronic pain syndrome

  20. The Effect of Experimental Parkinson on Formalin-Induced Pain in Rat

    Directory of Open Access Journals (Sweden)

    Mohammad Sofiabadi

    2014-04-01

    Full Text Available Background & Objectives : Pain is one of the preceding claims of Parkinson's disease (PD, that its mechanisms have not been fully identified. The purpose of this study was to investigate the chemical pain responses induced by subcutaneous injection of formalin in male parkinsonized rats.   Method : In this experimental study, 40 Wistar male rats were used and PD was established by stereotaxic injection of 6-OHDA toxin into the striatum. Parkinson's disease severity determined by apomorphine-induced rotation test and then the pain response of 4 groups, the control, sham and 2 weak or full Parkinson groups, were evaluated using formalin test. Data were analyzed using ANOVA and Tukey test.   Results : In both acute and chronic phases of the formalin test, the symptoms of pain in different groups were same, but at the interphase stage, pain intensity increased more in Parkinson 's rats, especially in full PD group compared to control (p<0.01.   Conclusion: These results suggest that the nigrostriatal dopaminergic pathway have important modulating role on chronic pain.

  1. Preoccupation in an early-romantic relationship predicts experimental pain relief.

    Science.gov (United States)

    Nilakantan, Aneesha; Younger, Jarred; Aron, Arthur; Mackey, Sean

    2014-06-01

    Individuals involved in the early stages of a passionate romantic relationship can be consumed by the experience and report emotional dependence and constant focus on their romantic partner. A few studies have shown that viewing pictures of a romantic partner can significantly reduce experimental pain. The strength of the effect, however, varies substantially between individuals. To study why some individuals experience significant pain reduction when looking at a picture of their partner, we examined partner preoccupation. We hypothesized that a greater degree of preoccupation in the early stages of a romantic relationship would be associated with greater analgesia during a pain induction task. Participants were shown pictures of their romantic partner or an equally attractive and familiar acquaintance while exposed to low, moderate, or high levels of thermal pain. Participants were also asked to rate how much time they spent thinking about their romantic partner during an average day. Degree of preoccupation was defined as the percentage of time participants spent thinking about their partner on an average day. In two separate experiments, viewing pictures of a romantic partner produced an analgesic effect. The degree of pain relief was positively correlated with partner preoccupation. The results suggest that preoccupation with a romantic partner during early stage romantic love is a predictor of pain relief when viewing pictures of the beloved. Wiley Periodicals, Inc.

  2. Using multilevel growth curve modeling to examine emotional modulation of temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR).

    Science.gov (United States)

    Rhudy, Jamie L; Martin, Satin L; Terry, Ellen L; Delventura, Jennifer L; Kerr, Kara L; Palit, Shreela

    2012-11-01

    Emotion can modulate pain and spinal nociception, and correlational data suggest that cognitive-emotional processes can facilitate wind-up-like phenomena (ie, temporal summation of pain). However, there have been no experimental studies that manipulated emotion to determine whether within-subject changes in emotion influence temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR, a physiological measure of spinal nociception). The present study presented a series of emotionally charged pictures (mutilation, neutral, erotic) during which electric stimuli at 2 Hz were delivered to the sural nerve to evoke TS-pain and TS-NFR. Participants (n=46 healthy; 32 female) were asked to rate their emotional reactions to pictures as a manipulation check. Pain outcomes were analyzed using statistically powerful multilevel growth curve models. Results indicated that emotional state was effectively manipulated. Further, emotion modulated the overall level of pain and NFR; pain and NFR were highest during mutilation and lowest during erotic pictures. Although pain and NFR both summated in response to the 2-Hz stimulation series, the magnitude of pain summation (TS-pain) and NFR summation (TS-NFR) was not modulated by picture-viewing. These results imply that, at least in healthy humans, within-subject changes in emotions do not promote central sensitization via amplification of temporal summation. However, future studies are needed to determine whether these findings generalize to clinical populations (eg, chronic pain). Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  3. Chenopodium ambrosioides L. Reduces Synovial Inflammation and Pain in Experimental Osteoarthritis.

    Directory of Open Access Journals (Sweden)

    Gustavo P Calado

    Full Text Available The chronicity of osteoarthritis (OA, characterized by pain and inflammation in the joints, is linked to a glutamate receptor, N-methyl-D-aspartate (NMDA. The use of plant species such as Chenopodium ambrosioides L. (Amaranthaceae as NMDA antagonists offers a promising perspective. This work aims to analyze the antinociceptive and anti-inflammatory responses of the crude hydroalcoholic extract (HCE of C. ambrosioides leaves in an experimental OA model. Wistar rats were separated into six groups (n = 24: clean (C, negative control (CTL-, positive control (CTL+, HCE0.5, HCE5 and HCE50. The first group received no intervention. The other groups received an intra-articular injection of sodium monoiodoacetate (MIA (8 mg/kg on day 0. After six hours, they were orally treated with saline, Maxicam plus (meloxicam + chondroitin sulfate and HCE at doses of 0.5 mg/kg, 5 mg/kg and 50 mg/kg, respectively. After three, seven and ten days, clinical evaluations were performed (knee diameter, mechanical allodynia, mechanical hyperalgesia and motor activity. On the tenth day, after euthanasia, synovial fluid and draining lymph node were collected for cellular quantification, and cartilage was collected for histopathological analysis. Finally, molecular docking was performed to evaluate the compatibility of ascaridole, a monoterpene found in HCE, with the NMDA receptor. After the third day, HCE reduced knee edema. HCE5 showed less cellular infiltrate in the cartilage and synovium and lower intensities of allodynia from the third day and of hyperalgesia from the seventh day up to the last treatment day. The HCE5 and HCE50 groups improved in forced walking. In relation to molecular docking, ascaridole showed NMDA receptor binding affinity. C. ambrosioides HCE was effective in the treatment of OA because it reduced synovial inflammation and behavioral changes due to pain. This effect may be related to the antagonistic effect of ascaridole on the NMDA receptor.

  4. Viewing pictures of a romantic partner reduces experimental pain: involvement of neural reward systems.

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    Jarred Younger

    2010-10-01

    Full Text Available The early stages of a new romantic relationship are characterized by intense feelings of euphoria, well-being, and preoccupation with the romantic partner. Neuroimaging research has linked those feelings to activation of reward systems in the human brain. The results of those studies may be relevant to pain management in humans, as basic animal research has shown that pharmacologic activation of reward systems can substantially reduce pain. Indeed, viewing pictures of a romantic partner was recently demonstrated to reduce experimental thermal pain. We hypothesized that pain relief evoked by viewing pictures of a romantic partner would be associated with neural activations in reward-processing centers. In this functional magnetic resonance imaging (fMRI study, we examined fifteen individuals in the first nine months of a new, romantic relationship. Participants completed three tasks under periods of moderate and high thermal pain: 1 viewing pictures of their romantic partner, 2 viewing pictures of an equally attractive and familiar acquaintance, and 3 a word-association distraction task previously demonstrated to reduce pain. The partner and distraction tasks both significantly reduced self-reported pain, although only the partner task was associated with activation of reward systems. Greater analgesia while viewing pictures of a romantic partner was associated with increased activity in several reward-processing regions, including the caudate head, nucleus accumbens, lateral orbitofrontal cortex, amygdala, and dorsolateral prefrontal cortex--regions not associated with distraction-induced analgesia. The results suggest that the activation of neural reward systems via non-pharmacologic means can reduce the experience of pain.

  5. Suprathreshold Heat Pain Response Predicts Activity-Related Pain, but Not Rest-Related Pain, in an Exercise-Induced Injury Model

    Science.gov (United States)

    Coronado, Rogelio A.; Simon, Corey B.; Valencia, Carolina; Parr, Jeffrey J.; Borsa, Paul A.; George, Steven Z.

    2014-01-01

    Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal. PMID:25265560

  6. Suprathreshold heat pain response predicts activity-related pain, but not rest-related pain, in an exercise-induced injury model.

    Directory of Open Access Journals (Sweden)

    Rogelio A Coronado

    Full Text Available Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR, a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal.

  7. Experimental allergic encephalomyelitis: peculiarities of pain-relieving therapy and place of anticonvulsants as analgetics

    Directory of Open Access Journals (Sweden)

    Nefyodov O.O.

    2015-11-01

    Full Text Available Multiple sclerosis (MS is the most common demyelinating disease affecting mainly young people of the working age (16-45 years and quickly leading to disability. Available data constitute that up to 80% of MS patients suffer from pain at different disease periods. Pain management and the analgesic drug choice in MS patients may be difficult. Anticonvulsant drugs possess an analgesic activity and are widely used in patients presenting painful neuropathic symptoms. Based on that, we aimed to investigate the nociceptive potential changes as well as the research-oriented behavior using the "open field" test in rat. An experimental animal equivalent of multiple sclerosis has been modeled, based on the methylprednisolone (M administration. Animals were also administered anticonvulsants (carbamazepine, topiramate, sodium volproat, pregabalin and gabapentin. The stu­dy showed advantages of gabapentin and pregabalin use in simulated disease treatment. This statement is based on the "open field" test results, where the motor-oriented rats’ behavior was evaluated. Administration of M+gabapentin and M+pregabalin showed positive dynamics of the motor activity: the number of squares crossed increased by 80.86% (p<0.05 and 81.73% (р<0.05 respectively. Maximum recovery of the research activity (peeking in "mink" was re­gis­tered in animals administered M+pregabalin: the increase rate was 300% (r<0.05 comparing with the 12th day of ex­periment. It was shown, that 5-days administration of M+gabapentin and M+pregabalin caused muscle tone impro­ve­ment by 190% (p<0.05 and 200% (p<0.05 respectively, comparing with animals with untreated multiple sclerosis. A sig­ni­fi­cant increase of analgesic activity of M+pregabalin and M+gabapentin combinations used together with me­thyl­pred­nisolone by 4.1 (p<0.05 and 3.6 (p<0.05 times was registered comparing with the initial methylprednisolone background.

  8. Pain

    Science.gov (United States)

    ... Grant Funding for Pain Initiatives Current Funding Opportunities Research on the Impact of Creative Arts in Military Populations More Health Professional Information Earn CME More Related Topics Chronic Pain ( NINDS ) NIH Pain Seminar Series Pain: You Can Get Help ( NIA ) NIH ...

  9. Anti-allodynic Effect of Nefopam and Morphine in a Rat Model of Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Taraneh Moini Zanjani

    2013-05-01

    Full Text Available Please cite this article as: Moini Zanjani T, Saghaei E, Ameli H, Sabetkasaei M. Anti-allodynic Effect of Nefopam and Morphine in a Rat Model of Neuropathic Pain. Novel Biomed 2013;1:16-22.Background: Neuropathic pain is a chronic pain due to a disorder in the peripheral or central nervous system with different pathophysiological mechanisms. Current treatments are not effective. Here we compared the analgesic effect of nefopam, and morphine in chronic constriction injury (CCI model of neuropathic pain.Methods: Male wistar rat (150-200g, n=8 were divided into 3 different groups: 1- Saline-treated CCI group, 2- Saline-treated sham group, and 3- Drug-treated CCI groups. In CCI model of neuropathic pain, the left sciatic nerve was exposed and 4 loose chromic gut ligatures were placed around the nerve proximal to the trifurcation. Ketamine 60mg/kg and xylazine 10 mg/kg were used for anesthesia. Nefopam (10, 20, 30mg/kg, and morphine (1, 3, 5mg/kg were injected 30 minutes before surgery and continued daily to day 14 post-ligation. Von Frey filaments for mechanical allodynia and acetone test for cold allodynia were respectively used as pain behavioral tests. Experiments were performed on day 0 (before surgery and days 1, 3, 5,7,10 and 14 post injury. Behavioral studies were performed in a quiet room between 9:00 to 11:00 AM. All experiments followed the IASP guidelines on ethical standards for investigation of experimental pain in animals.Results: Nefopam (20 and 30mg/kg blocked mechanical and cold allodynia during the experimental period, but the analgesic effects of morphine (5mg/kg lasted for 7 days.Conclusions: It seems that nefopam could effectively reduce pain behavior compared to morphine with reduced adverse effects.

  10. Stress-induced allodynia--evidence of increased pain sensitivity in healthy humans and patients with chronic pain after experimentally induced psychosocial stress.

    Directory of Open Access Journals (Sweden)

    Benjamin Crettaz

    Full Text Available BACKGROUND: Experimental stress has been shown to have analgesic as well as allodynic effect in animals. Despite the obvious negative influence of stress in clinical pain conditions, stress-induced alteration of pain sensitivity has not been tested in humans so far. Therefore, we tested changes of pain sensitivity using an experimental stressor in ten female healthy subjects and 13 female patients with fibromyalgia. METHODS: Multiple sensory aspects of pain were evaluated in all participants with the help of the quantitative sensory testing protocol before (60 min and after (10 and 90 min inducing psychological stress with a standardized psychosocial stress test ("Trier Social Stress Test". RESULTS: Both healthy subjects and patients with fibromyalgia showed stress-induced enhancement of pain sensitivity in response to thermal stimuli. However, only patients showed increased sensitivity in response to pressure pain. CONCLUSIONS: Our results provide evidence for stress-induced allodynia/hyperalgesia in humans for the first time and suggest differential underlying mechanisms determining response to stressors in healthy subjects and patients suffering from chronic pain. Possible mechanisms of the interplay of stress and mediating factors (e.g. cytokines, cortisol on pain sensitivity are mentioned. Future studies should help understand better how stress impacts on chronic pain conditions.

  11. Paroxetine attenuates the development and existing pain in a rat model of neurophatic pain.

    Science.gov (United States)

    Zarei, Malek; Sabetkasaei, Masoumeh; Moini Zanjani, Taraneh

    2014-01-01

    P2X4 receptor (P2X4R), a purinoceptor expressed in activated spinal microglia, plays a key role in the pathogenesis of neuropathic pain. Spinal nerve injury induces up-regulation of P2X4R on activated microglia in the spinal cord, and blockade of this receptor can reduce neuropathic pain. The present study was undertaken to determine whether paroxetine, an inhibitor of P2X4R, could attenuate allodynia and hyperalgesia in chronic constriction injury (CCI) model of neuropathic pain when used preemptively or after the sciatic nerve injury. Male Wistar rats (150-200 g, n = 6) were divided into 3 different groups: 1- CCI vehicle-treated group, 2- Sham group, and 3- CCI paroxetine-treated group. Paroxetine (10 mg/kg, i.p.) was administered 1 h before surgery and continued daily until day 14. In other part of the study, paroxetine (10 mg/kg, i.p.) was administered at day 7 post injury and continued daily until day 14. von Frey filaments for mechanical allodynia and analgesia meter for thermal hyperalgesia were used to assay pain behavior. In a preventive paradigm, paroxetine significantly attenuated both mechanical allodynia and thermal hyperalgesia (Pparoxetine on existing allodynia (Pparoxetine can attenuate pain behavior when administered before and also after sciatic nerve injury in CCI model of neuropathic pain.

  12. Prices need no preferences: social trends determine decisions in experimental markets for pain relief.

    Science.gov (United States)

    Vlaev, Ivo; Seymour, Ben; Chater, Nick; Winston, Joel S; Yoshida, Wako; Wright, Nicholas; Symmonds, Mkael; Dolan, Ray

    2014-01-01

    A standard view in health economics is that, although there is no market that determines the "prices" for health states, people can nonetheless associate health states with monetary values (or other scales, such as quality adjusted life year [QALYs] and disability adjusted life year [DALYs]). Such valuations can be used to shape health policy, and a major research challenge is to elicit such values from people; creating experimental "markets" for health states is a theoretically attractive way to address this. We explore the possibility that this framework may be fundamentally flawed-because there may not be any stable values to be revealed. Instead, perhaps people construct ad hoc values, influenced by contextual factors, such as the observed decisions of others. The participants bid to buy relief from equally painful electrical shocks to the leg and arm in an experimental health market based on an interactive second-price auction. Thirty subjects were randomly assigned to two experimental conditions where the bids by "others" were manipulated to follow increasing or decreasing price trends for one, but not the other, pain. After the auction, a preference test asked the participants to choose which pain they prefer to experience for a longer duration. Players remained indifferent between the two pain-types throughout the auction. However, their bids were differentially attracted toward what others bid for each pain, with overbidding during decreasing prices and underbidding during increasing prices. Health preferences are dissociated from market prices, which are strongly referenced to others' choices. This suggests that the price of health care in a free-market has the capacity to become critically detached from people's underlying preferences. 2014 APA, all rights reserved

  13. Experimental orofacial pain and sensory deprivation lead to perceptual distortion of the face in healthy volunteers.

    Science.gov (United States)

    Dagsdóttir, Lilja Kristín; Skyt, Ina; Vase, Lene; Baad-Hansen, Lene; Castrillon, Eduardo; Svensson, Peter

    2015-09-01

    Patients suffering from persistent orofacial pain may sporadically report that the painful area feels "swollen" or "differently," a phenomenon that may be conceptualized as a perceptual distortion because there are no clinical signs of swelling present. Our aim was to investigate whether standardized experimental pain and sensory deprivation of specific orofacial test sites would lead to changes in the size perception of these face areas. Twenty-four healthy participants received either 0.2 mL hypertonic saline (HS) or local anesthetics (LA) into six regions (buccal, mental, lingual, masseter muscle, infraorbital and auriculotemporal nerve regions). Participants estimated the perceived size changes in percentage (0 % = no change, -100 % = half the size or +100 % = double the size), and somatosensory function was checked with tactile stimuli. The pain intensity was rated on a 0-10 Verbal Numerical Rating Scale (VNRS), and sets of psychological questionnaires were completed. HS and LA were associated with significant self-reported perceptual distortions as indicated by consistent increases in perceived size of the adjacent face areas (P ≤ 0.050). Perceptual distortion was most pronounced in the buccal region, and the smallest increase was observed in the auriculotemporal region. HS was associated with moderate levels of pain VNRS = 7.3 ± 0.6. Weak correlations were found between HS-evoked perceptual distortion and level of dissociation in two regions (P pain and transient sensory deprivation evoked perceptual distortions in all face regions and overall demonstrated the importance of afferent inputs for the perception of the face. We propose that perceptual distortion may be an important phenomenon to consider in persistent orofacial pain conditions.

  14. Modeling subjective well-being in individuals with chronic pain and a physical disability: the role of pain control and pain catastrophizing.

    Science.gov (United States)

    Furrer, Angela; Michel, Gisela; Terrill, Alexandra L; Jensen, Mark P; Müller, Rachel

    2017-10-23

    To investigate the associations between subjective well-being and pain intensity, pain interference, and depression in individuals with physical disabilities. We hypothesized that (1) pain control and (2) pain catastrophizing mediate the effects of subjective well-being on pain intensity, pain interference, and depression. Analyses of cross-sectional data from 96 individuals diagnosed with spinal cord injury, multiple sclerosis, neuromuscular disease, or post-polio syndrome, with average pain intensity of ≥4 (0-10) on at least half the days in the past month. Two models tested study hypotheses using structural equation. Both models showed acceptable model fit. Pain catastrophizing significantly mediated the effect of subjective well-being on pain intensity and pain interference, but not on depression. Pain control did not significantly mediate the effect of subjective well-being on pain intensity, pain interference, or depression. Path coefficients showed significant direct effects of subjective well-being on pain control (β = 0.39), pain catastrophizing (β = -0.61), pain interference (β = -0.48; -0.42), and depression (β = -0.75; -0.78). This study supports the potential of enhancing subjective well-being and lowering pain catastrophizing for reducing pain intensity, pain interference, and depressive symptoms in individuals with chronic pain and a physical disability. The findings indicate that true experiments to test for causal associations are warranted. Implications for rehabilitation The majority of individuals with physical disabilities report having persistent moderate-to-severe pain that may negatively limit daily activities and quality of life. The present cross-sectional study indicates that individuals who reported greater subjective well-being showed significantly lower pain intensity via the mediating effect of lower pain catastrophizing. Since sample size and respective power are low, these findings should be taken as first

  15. Complex regional pain syndrome (CRPS) or continuous unilateral distal experimental pain stimulation in healthy subjects does not bias visual attention towards one hemifield.

    Science.gov (United States)

    Filippopulos, Filipp M; Grafenstein, Jessica; Straube, Andreas; Eggert, Thomas

    2015-11-01

    In natural life pain automatically draws attention towards the painful body part suggesting that it interacts with different attentional mechanisms such as visual attention. Complex regional pain syndrome (CRPS) patients who typically report on chronic distally located pain of one extremity may suffer from so-called neglect-like symptoms, which have also been linked to attentional mechanisms. The purpose of the study was to further evaluate how continuous pain conditions influence visual attention. Saccade latencies were recorded in two experiments using a common visual attention paradigm whereby orientating saccades to cued or uncued lateral visual targets had to be performed. In the first experiment saccade latencies of healthy subjects were measured under two conditions: one in which continuous experimental pain stimulation was applied to the index finger to imitate a continuous pain situation, and one without pain stimulation. In the second experiment saccade latencies of patients suffering from CRPS were compared to controls. The results showed that neither the continuous experimental pain stimulation during the experiment nor the chronic pain in CRPS led to an unilateral increase of saccade latencies or to a unilateral increase of the cue effect on latency. The results show that unilateral, continuously applied pain stimuli or chronic pain have no or only very limited influence on visual attention. Differently from patients with visual neglect, patients with CRPS did not show strong side asymmetries of saccade latencies or of cue effects on saccade latencies. Thus, neglect-like clinical symptoms of CRPS patients do not involve the allocation of visual attention.

  16. Effects of experimental muscle pain on shoulder-abduction force steadiness and muscle activity in healthy subjects

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Rasmussen, Lars; Aagaard, Per

    2007-01-01

    We previously demonstrated that the steadiness of shoulder abduction is reduced in patients with subacromial impingement syndrome (SIS), which might be related to shoulder pain associated with the SIS. The aim of the present study was to examine the acute effects of experimental shoulder muscle...... pain on shoulder motor function in healthy subjects. The fluctuations in exerted force (force steadiness) and electromyographic (EMG) activity from eight shoulder muscles were determined during sub-maximal isometric and dynamic contractions with the shoulder abductors in nine healthy subjects (27.......7 +/- 4.2 years, mean +/- 1 SD) before, during and after experimental pain induction. Experimental pain was induced by bolus injections of 6% hypertonic saline into the supraspinatus muscle. Experimental muscle pain reduced shoulder-abduction force steadiness on average by 21% during isometric...

  17. New model systems for experimental evolution.

    Science.gov (United States)

    Collins, Sinéad

    2013-07-01

    Microbial experimental evolution uses a few well-characterized model systems to answer fundamental questions about how evolution works. This special section highlights novel model systems for experimental evolution, with a focus on marine model systems that can be used to understand evolutionary responses to global change in the oceans. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  18. Rethinking the Psychogenic Model of Complex Regional Pain Syndrome: Somatoform Disorders and Complex Regional Pain Syndrome

    Science.gov (United States)

    Hill, Renee J.; Chopra, Pradeep; Richardi, Toni

    2012-01-01

    Abstract Explaining the etiology of Complex Regional Pain Syndrome (CRPS) from the psychogenic model is exceedingly unsophisticated, because neurocognitive deficits, neuroanatomical abnormalities, and distortions in cognitive mapping are features of CRPS pathology. More importantly, many people who have developed CRPS have no history of mental illness. The psychogenic model offers comfort to physicians and mental health practitioners (MHPs) who have difficulty understanding pain maintained by newly uncovered neuro inflammatory processes. With increased education about CRPS through a biopsychosocial perspective, both physicians and MHPs can better diagnose, treat, and manage CRPS symptomatology. PMID:24223338

  19. Rethinking the psychogenic model of complex regional pain syndrome: somatoform disorders and complex regional pain syndrome.

    Science.gov (United States)

    Hill, Renee J; Chopra, Pradeep; Richardi, Toni

    2012-01-01

    Explaining the etiology of Complex Regional Pain Syndrome (CRPS) from the psychogenic model is exceedingly unsophisticated, because neurocognitive deficits, neuroanatomical abnormalities, and distortions in cognitive mapping are features of CRPS pathology. More importantly, many people who have developed CRPS have no history of mental illness. The psychogenic model offers comfort to physicians and mental health practitioners (MHPs) who have difficulty understanding pain maintained by newly uncovered neuro inflammatory processes. With increased education about CRPS through a biopsychosocial perspective, both physicians and MHPs can better diagnose, treat, and manage CRPS symptomatology.

  20. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    Kristensen, Niels Rode; Madsen, Henrik; Jørgensen, Sten Bay

    2003-01-01

    unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance......A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  1. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance......A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  2. Psychosocial Pain Management Moderation: The Limit, Activate, and Enhance Model.

    Science.gov (United States)

    Day, Melissa A; Ehde, Dawn M; Jensen, Mark P

    2015-10-01

    There is a growing emphasis in the pain literature on understanding the following second-order research questions: Why do psychosocial pain treatments work? For whom do various treatments work? This critical review summarizes research that addresses the latter question and proposes a moderation model to help guide future research. A theoretical moderation framework for matching individuals to specific psychosocial pain interventions has been lacking. However, several such frameworks have been proposed in the broad psychotherapy and implementation science literature. Drawing on these theories and adapting them specifically for psychosocial pain treatment, here we propose a Limit, Activate, and Enhance model of pain treatment moderation. This model is unique in that it includes algorithms not only for matching treatments on the basis of patient weaknesses but also for directing patients to interventions that build on their strengths. Critically, this model provides a basis for specific a priori hypothesis generation, and a selection of the possible hypotheses drawn from the model are proposed and discussed. Future research considerations are presented that could refine and expand the model based on theoretically driven empirical evidence. The Limit, Activate, and Enhance model presented here is a theoretically derived framework that provides an a priori basis for hypothesis generation regarding psychosocial pain treatment moderators. The model will advance moderation research via its unique focus on matching patients to specific treatments that (1) limit maladaptive responses, (2) activate adaptive responses, and (3) enhance treatment outcomes based on patient strengths and resources. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  3. Model refinement for offshore platforms: Experimental study

    Science.gov (United States)

    Zhang, Min; Chen, Zongli; Wu, Yanjian

    2017-08-01

    Offshore jacket platforms are widely used in offshore oil and gas exploitation. Finite element models of such structures need to have many degrees of freedom (DOFs) to represent the geometrical detail of complex structures, thereby leading to incompatibility in the number of DOFs of experimental models. To bring them both to the same order while ensuring that the essential eigen- properties of the refined model match those of experimental models, an extended model refinement procedure is presented in this paper. Vibration testing of an offshore jacket platform model is performed to validate the applicability of the proposed approach. A full-order finite element model of the platform is established and then tuned to meet the measured modal properties identified from the acceleration signals. Both model reduction and modal expansion methods are investigated, as well as various scenarios of sensor arrangements. Upon completion of the refinement, the updated jacket platform model matches the natural frequencies of the measured model well.

  4. Experimental models of demyelination and remyelination.

    Science.gov (United States)

    Torre-Fuentes, L; Moreno-Jiménez, L; Pytel, V; Matías-Guiu, J A; Gómez-Pinedo, U; Matías-Guiu, J

    2017-08-29

    Experimental animal models constitute a useful tool to deepen our knowledge of central nervous system disorders. In the case of multiple sclerosis, however, there is no such specific model able to provide an overview of the disease; multiple models covering the different pathophysiological features of the disease are therefore necessary. We reviewed the different in vitro and in vivo experimental models used in multiple sclerosis research. Concerning in vitro models, we analysed cell cultures and slice models. As for in vivo models, we examined such models of autoimmunity and inflammation as experimental allergic encephalitis in different animals and virus-induced demyelinating diseases. Furthermore, we analysed models of demyelination and remyelination, including chemical lesions caused by cuprizone, lysolecithin, and ethidium bromide; zebrafish; and transgenic models. Experimental models provide a deeper understanding of the different pathogenic mechanisms involved in multiple sclerosis. Choosing one model or another depends on the specific aims of the study. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. CONGESTIVE HEART FAILURE: EXPERIMENTAL MODEL

    Directory of Open Access Journals (Sweden)

    Antonio Francesco Corno

    2013-10-01

    Full Text Available INTRODUCTION.Surgically induced, combined volume and pressure overload has been used in rabbits to create a simplified and reproducible model of acute left ventricular (LV failure.MATERIALS AND METHODS.New Zealand white male rabbits (n=24, mean weight 3.1±0.2kg were randomly assigned to either the Control group (n=10 or to the Heart Failure group (HF, n=14. Animals in the Control group underwent sham procedures. Animals in the HF group underwent procedures to induce LV volume overload by inducing severe aortic valve regurgitation with aortic cusp disruption and pressure overload using an occlusive silver clip positioned around the pre-renal abdominal aorta.RESULTS.Following Procedure-1 (volume overload echocardiography confirmed severe aortic regurgitation in all animals in the HF group, with increased mean pulse pressure difference from 18±3mmHg to 38±3mmHg (P

  6. Traumatization and chronic pain: a further model of interaction

    Directory of Open Access Journals (Sweden)

    Egloff N

    2013-11-01

    Full Text Available Niklaus Egloff,1 Anna Hirschi,2 Roland von Känel1 1Department of General Internal Medicine, Division of Psychosomatic Medicine, Inselspital, University Hospital, Bern, Switzerland; 2Outpatient Clinic for Victims of Torture and War, Swiss Red Cross, Bern-Wabern, Switzerland Abstract: Up to 80% of patients with severe posttraumatic stress disorder are suffering from “unexplained” chronic pain. Theories about the links between traumatization and chronic pain have become the subject of increased interest over the last several years. We will give a short summary about the existing interaction models that emphasize particularly psychological and behavioral aspects of this interaction. After a synopsis of the most important psychoneurobiological mechanisms of pain in the context of traumatization, we introduce the hypermnesia–hyperarousal model, which focuses on two psychoneurobiological aspects of the physiology of learning. This hypothesis provides an answer to the hitherto open question about the origin of pain persistence and pain sensitization following a traumatic event and also provides a straightforward explanatory model for educational purposes. Keywords: posttraumatic stress disorder, chronic pain, hypermnesia, hypersensitivity, traumatization

  7. Improving the physiological realism of experimental models.

    Science.gov (United States)

    Vinnakota, Kalyan C; Cha, Chae Y; Rorsman, Patrik; Balaban, Robert S; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A; Jeneson, Jeroen A L

    2016-04-06

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these models rely on the analysis and integration of experimental data. As such, the success of VPH depends on the availability of physiologically realistic experimental models (E-Models) of human organ function that can be parametrized to test the numerical models. Here, the current state of suitable E-models, ranging from in vitro non-human cell organelles to in vivo human organ systems, is discussed. Specifically, challenges and recent progress in improving the physiological realism of E-models that may benefit the VPH project are highlighted and discussed using examples from the field of research on cardiovascular disease, musculoskeletal disorders, diabetes and Parkinson's disease.

  8. Impaired behavioural pain responses in hph-1 mice with inherited deficiency in GTP cyclohydrolase 1 in models of inflammatory pain

    DEFF Research Database (Denmark)

    Nasser, Arafat; Bjerrum, Ole J; Heegaard, Anne-Marie

    2013-01-01

    1 gene results in decreased basal GCH1 expression, and is associated with DOPA-responsive dystonia (DRD). So far it is unknown if such mutations affect acute and inflammatory pain.Results: In the current study, we examined the involvement of the GCH1 gene in pain models using...... the hyperphenylalaninemia 1 (hph-1) mouse, a genetic model for DRD, with only 10% basal GTP-CH1 activity compared to wild type mice. The study included assays for determination of acute nociception as well as models for pain after sensitisation. Pain behavioural analysis of the hph-1 mice showed reduced pain-like responses......Background: GTP cyclohydrolase 1 (GTP-CH1), the rate-limiting enzyme in the synthesis of tetrahydrobiopterin (BH4), encoded by the GCH1 gene, has been implicated in the development and maintenance of inflammatory pain in rats. In humans, homozygous carriers of a " pain-protective" (PP) haplotype...

  9. Understanding Leadership: An Experimental-Experiential Model

    Science.gov (United States)

    Hole, George T.

    2014-01-01

    Books about leadership are dangerous to readers who fantasize about being leaders or apply leadership ideas as if they were proven formulas. As an antidote, I offer an experimental framework in which any leadership-management model can be tested to gain experiential understanding of the model. As a result one can gain reality-based insights about…

  10. A systematic review of animal models for experimental neuroma.

    Science.gov (United States)

    Toia, Francesca; Giesen, Thomas; Giovanoli, Pietro; Calcagni, Maurizio

    2015-10-01

    Peripheral neuromas can result in an unbearable neuropathic pain and functional impairment. Their treatment is still challenging, and their optimal management is to be defined. Experimental research still plays a major role, but - although numerous neuroma models have been proposed on different animals - there is still no single model recognised as being the reference. Several models show advantages over the others in specific aspects of neuroma physiopathology, prevention or treatment, making it unlikely that a single model could be of reference. A reproducible and standardised model of peripheral neuroma would allow better comparison of results from different studies. We present a systematic review of the literature on experimental in vivo models, analysing advantages and disadvantages, specific features and indications, with the goal of providing suggestions to help their standardisation. Published models greatly differ in the animal and the nerve employed, the mechanisms of nerve injury and the evaluation methods. Specific experimental models exist for terminal neuromas and neuromas in continuity (NIC). The rat is the most widely employed animal, the rabbit being the second most popular model. NIC models are more actively researched, but it is more difficult to generate such studies in a reproducible manner. Nerve transection is considered the best method to cause terminal neuromas, whereas partial transection is the best method to cause NIC. Traditional histomorphology is the historical gold-standard evaluation method, but immunolabelling, reverse transcriptase-polymerase chain reaction (RT-PCR) and proteomics are gaining increasing popularity. Computerised gait analysis is the gold standard for motor-recovery evaluation, whereas mechanical testing of allodynia and hyperalgesia reproducibly assesses sensory recovery. This review summarises current knowledge on experimental neuroma models, and it provides a useful tool for defining experimental protocols

  11. Isolated and Combined Effects of Electroacupuncture and Meditation in Reducing Experimentally Induced Ischemic Pain: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Kyung-Eun Choi

    2011-01-01

    Full Text Available Acupuncture and meditation are promising treatment options for clinical pain. However, studies investigating the effects of these methods on experimental pain conditions are equivocal. Here, the effects of electroacupuncture (EA and meditation on the submaximum effort tourniquet technique (SETT, a well-established, opiate-sensitive pain paradigm in experimental placebo research were studied. Ten experienced meditators (6 male subjects and 13 nonmeditators (6 male subjects were subjected to SETT (250 mmHG on one baseline (SETT only and two treatment days (additional EA contralaterally to the SETT, either at the leg on ST36 and LV3 or at the arm on LI4 and LI10 in randomized order. Numeric Rating Scale (NRS ratings (scale 0–10 were recorded every 3 min. During baseline, meditation induced significantly greater pain tolerance in meditators when compared with the control group. Both the EA conditions significantly increased pain tolerance and reduced pain ratings in controls. Furthermore, EA diminished the group difference in pain sensitivity, indicating that meditators had no additional benefit from acupuncture. The data suggest that EA as a presumable bottom-up process may be as effective as meditation in controlling experimental SETT pain. However, no combined effect of both the techniques could be observed.

  12. The Comparative Effects of Spinal and Peripheral Thrust Manipulation and Exercise on Pain Sensitivity and the Relation to Clinical Outcome: A Mechanistic Trial Using a Shoulder Pain Model

    Science.gov (United States)

    Coronado, Rogelio A.; Bialosky, Joel E.; Bishop, Mark D.; Riley, Joseph L.; Robinson, Michael E.; Michener, Lori A.; George, Steven Z.

    2016-01-01

    STUDY DESIGN Single-blind randomized trial. OBJECTIVES To compare the effects of cervical and shoulder thrust manipulation (TM) and exercise on pain sensitivity, and to explore associations with clinical outcomes in patients with shoulder pain. BACKGROUND Experimental studies indicate that spinal TM has an influence on central pain processes, supporting its application for treatment of extremity conditions. Direct comparison of spinal and peripheral TM on pain sensitivity has not been widely examined. METHODS Seventy-eight participants with shoulder pain (36 female; mean ± SD age, 39.0 ± 14.5 years) were randomized to receive 3 treatments of cervical TM (n = 26), shoulder TM (n = 27), or shoulder exercise (n = 25) over 2 weeks. Twenty-five healthy participants (13 female; mean ± SD age, 35.2 ± 11.1 years) were assessed to compare pain sensitivity with that in clinical participants at baseline. Primary outcomes were changes in local (eg, shoulder) and remote (eg, tibialis anterior) pressure pain threshold and heat pain threshold occurring over 2 weeks. Secondary outcomes were shoulder pain intensity and patient-rated function at 4, 8, and 12 weeks. Analysis-of-variance models and partial-correlation analyses were conducted to examine comparative effects and the relationship between measures. RESULTS At baseline, clinical participants demonstrated lower local (mean difference, −1.63 kg; 95% confidence interval [CI]: −2.40, −0.86) and remote pressure pain threshold (mean difference, −1.96 kg; 95% CI: −3.09, −0.82) and heat pain threshold (mean difference, −1.15°C; 95% CI: −2.06, −0.24) compared to controls, suggesting enhanced pain sensitivity. Following intervention, there were no between-group differences in pain sensitivity or clinical outcome (P>.05). However, improvements were noted, regardless of intervention, for pressure pain threshold (range of mean differences, 0.22–0.32 kg; 95% CI: 0.03, 0.43), heat pain threshold (range of mean

  13. Remote Effects of Electromagnetic Millimeter Waves on Experimentally Induced Cold Pain: A Double-Blinded Crossover Investigation in Healthy Volunteers.

    Science.gov (United States)

    Partyla, Tomasz; Hacker, Henriette; Edinger, Hardy; Leutzow, Bianca; Lange, Joern; Usichenko, Taras

    2017-03-01

    The hypoalgesic effect of electromagnetic millimeter waves (MW) is well studied in animal model; however, the results of human research are controversial. The aim of this study was to evaluate the effects of various frequency ranges of MW on hypoalgesia using the cold pressor test (CPT). Experimental pain was induced using standardized CPT protocols in 20 healthy male volunteers. The skin of the lower part of sternum was exposed to MW with a frequency of 42.25 GHz (active generator); MW within 50-75 GHz frequency range (noise generator); or an inactive MW device (placebo generator) in a random crossover double-blinded manner. Pain threshold, measured using the CPT, was the primary outcome. Other CPT parameters, heart rate, blood pressure, incidence of subjective sensations (paresthesia) during exposure, as well as quality of volunteers' blinding were also recorded. The end points of the condition with exposure to 42.25 GHz, were compared with baseline; exposure to noise 50-75 GHz; and placebo generators. Pain threshold increased during exposure to the 42.25 GHz generator when compared with baseline: median difference (MD), 1.97 seconds (95% confidence interval [CI], 0.35-3.73) and noise generator: MD, 1.27 seconds (95% CI, 0.05-2.33) but not compared with the placebo generator. Time to onset of cold and increasing pain sensations as well as diastolic blood pressure increased under the exposure to the 42.25 GHz generator when compared with baseline and noise generator. Other outcome measures were comparable among the study conditions. We were able to partially confirm the previously suggested hypoalgesic effects of low-intensity electromagnetic MW. However, the effect was indistinguishable from the placebo condition in our investigation.

  14. Concept priming and pain: an experimental approach to understanding gender roles in sex-related pain differences.

    Science.gov (United States)

    Fowler, Stephanie L; Rasinski, Heather M; Geers, Andrew L; Helfer, Suzanne G; France, Christopher R

    2011-04-01

    Prior research has found that sex differences in pain are partially due to individual variations in gender roles. In a laboratory study, we tested the hypothesis that the presence of covert gender role cues can also moderate the extent to which women and men experience pain. Specifically, we varied gender role cues by asking male and female participants to write about instances in which they behaved in a stereotypically feminine, masculine, or neutral manner. Pain and cardiovascular reactivity to the cold pressor task were then assessed. Results revealed that, when primed with femininity, men reported less pain and anxiety from the cold pressor task than women. However, no differences existed between the sexes in the masculine or neutral prime conditions. The results indicate that covert gender cues can alter pain reports. Further, at least in some situations, feminine role cues may be more influential on pain reports than masculine role cues.

  15. Sacroiliac joint pain: Prospective, randomised, experimental and comparative study of thermal radiofrequency with sacroiliac joint block.

    Science.gov (United States)

    Cánovas Martínez, L; Orduña Valls, J; Paramés Mosquera, E; Lamelas Rodríguez, L; Rojas Gil, S; Domínguez García, M

    2016-05-01

    To compare the analgesic effects between the blockade and bipolar thermal radiofrequency in the treatment of sacroiliac joint pain. Prospective, randomised and experimental study conducted on 60 patients selected in the two hospitals over a period of nine months, who had intense sacroiliac joint pain (Visual Analogue Scale [VAS]>6) that lasted more than 3 months. Patients were randomised into three groups (n=20): Group A (two intra-articular sacroiliac injections of local anaesthetic/corticosteroid guided by ultrasound in 7 days). Group B: conventional bipolar radiofrequency "palisade". Target points were the lateral branch nerves of S1, S2, and S3, distance needles 1cm. Group C: modified bipolar radiofrequency "palisade" (needle distance >1cm). Patients were evaluated at one month, three months, and one year. Demographic data, VAS reduction, and side effects of the techniques were assessed. One month after the treatment, pain reduction was >50% in the three groups PDolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Modeling of Experimental Adsorption Isotherm Data

    Directory of Open Access Journals (Sweden)

    Xunjun Chen

    2015-01-01

    Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

  17. Experimental Concepts for Testing Seismic Hazard Models

    Science.gov (United States)

    Marzocchi, W.; Jordan, T. H.

    2015-12-01

    Seismic hazard analysis is the primary interface through which useful information about earthquake rupture and wave propagation is delivered to society. To account for the randomness (aleatory variability) and limited knowledge (epistemic uncertainty) of these natural processes, seismologists must formulate and test hazard models using the concepts of probability. In this presentation, we will address the scientific objections that have been raised over the years against probabilistic seismic hazard analysis (PSHA). Owing to the paucity of observations, we must rely on expert opinion to quantify the epistemic uncertainties of PSHA models (e.g., in the weighting of individual models from logic-tree ensembles of plausible models). The main theoretical issue is a frequentist critique: subjectivity is immeasurable; ergo, PSHA models cannot be objectively tested against data; ergo, they are fundamentally unscientific. We have argued (PNAS, 111, 11973-11978) that the Bayesian subjectivity required for casting epistemic uncertainties can be bridged with the frequentist objectivity needed for pure significance testing through "experimental concepts." An experimental concept specifies collections of data, observed and not yet observed, that are judged to be exchangeable (i.e., with a joint distribution independent of the data ordering) when conditioned on a set of explanatory variables. We illustrate, through concrete examples, experimental concepts useful in the testing of PSHA models for ontological errors in the presence of aleatory variability and epistemic uncertainty. In particular, we describe experimental concepts that lead to exchangeable binary sequences that are statistically independent but not identically distributed, showing how the Bayesian concept of exchangeability generalizes the frequentist concept of experimental repeatability. We also address the issue of testing PSHA models using spatially correlated data.

  18. Attachment Style and Chronic Pain: Toward an Interpersonal Model of Pain.

    Science.gov (United States)

    Romeo, Annunziata; Tesio, Valentina; Castelnuovo, Gianluca; Castelli, Lorys

    2017-01-01

    Chronic pain (CP) is a burdensome symptom. Different psychological models have been proposed to explain the role of psychological and social factors in developing and maintaining CP. Attachment, for example, is a psychological construct of possible relevance in CP. The first studies on the role of attachment in CP did not investigate the partner's psychological factors, thus neglecting the influence of the latter. The main aim of this mini-review was to examine the more recent literature investigating the relationship between CP and attachment style. In particular, whether or not more recent studies assessed the psychological variables of a patient's partner. The articles were selected from the Medline/PubMed database using the search terms "attachment" AND "pain"; "CP" AND "attachment style," which led to nine papers being identified. The results showed that, even though the key point was still the hypothesis that an insecure attachment style is associated with CP, in recent years researchers have focused on the possible psychological aspects mediating between attachment style and CP. In particular, worrying, coping strategies, catastrophizing and perceived spouse responses to pain behavior were taken into account. Only one study considered the role of the reciprocal influence of attachment style of both patient and partner, underlining the role of real significant others' responses to pain behaviors. In conclusion, the results of the present mini-review highlight how in recent years researchers have moved toward investigating those psychological aspects that could mediate the relationship between attachment and CP, while only partially evaluating the interpersonal perspective.

  19. Experimental deep brain stimulation in animal models.

    Science.gov (United States)

    Tan, Sonny Kh; Vlamings, Rinske; Lim, Leewei; Sesia, Thibault; Janssen, Marcus Lf; Steinbusch, Harry Wm; Visser-Vandewalle, Veerle; Temel, Yasin

    2010-10-01

    DEEP BRAIN STIMULATION (DBS) as a therapy in neurological and psychiatric disorders is widely applied in the field of functional and stereotactic neurosurgery. In this respect, experimental DBS in animal models is performed to evaluate new indications and new technology. In this article, we review our experience with the concept of experimental DBS, including its development and validation. An electrode construction was developed using clinical principles to perform DBS unilaterally or bilaterally in freely moving rats. The stimulation parameters were adjusted for the rat using current density calculations. We performed validation studies in 2 animal models: a rat model of Parkinson's disease (bilateral 6-hydroxydopamine infusion in the striatum) and a rat model of Huntington's disease (transgenic rats). The effects of DBS were evaluated in different behavioral tasks measuring motor and cognitive functions. The electrode construction developed allows experimental DBS to be performed in freely moving rats. With the current setup, electrodes are placed in the target in 70% to 95% of the cases. Using a rat model, we showed that bilateral DBS of the subthalamic nucleus improves parkinsonian motor disability, but can induce behavioral side effects, similar to the clinical situation. In addition, we showed that DBS of the globus pallidus can improve motor and cognitive symptoms in a rat model of Huntington's disease. Nevertheless, during the process of the development and validation of experimental DBS, we encountered specific problems. These are discussed in detail. Experimental DBS in freely moving animals is an adequate tool to explore new indications for DBS and to refine DBS technology.

  20. Prospects of experimentally reachable beyond Standard Model ...

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 2. Prospects of experimentally reachable beyond Standard Model physics in inverse see-saw motivated SO(10) GUT. Ram Lal Awasthi. Special: Supersymmetric Unified Theories and Higgs Physics Volume 86 Issue 2 February 2016 pp 223- ...

  1. Prospects of experimentally reachable beyond Standard Model ...

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... also fit perfectly in the model framework. Despite the fact that SM has unravelled the gauge origin of fundamental forces and the structure of Universe while successfully confronting numerous experimental tests, it has various limitations. For a good summary on its excellencies and compulsions see [1], and.

  2. Monitoring heart rate variability to assess experimentally induced pain using the analgesia nociception index: A randomised volunteer study.

    Science.gov (United States)

    Jess, Gunnar; Pogatzki-Zahn, Esther M; Zahn, Peter K; Meyer-Frießem, Christine H

    2016-02-01

    Pain assessment using a numerical rating scale (NRS) is considered good clinical practice, but objective assessment in noncommunicating patients is still a challenge. A potential solution is to monitor changes in heart rate variability transformed into the analgesia nociception index (ANI), that offers a noninvasive means of pain quantification. The aim was to measure magnitudes, descending slopes and time courses of ANI following expected and unexpected painful, nonpainful and sham experimental stimuli and compare these with pain intensity as assessed by NRS in conscious human volunteers. We expected a negative correlation between ANI and NRS after painful stimuli. Randomised stimuli and placebo-controlled, single-blinded study. Experimental pain simulation laboratory, Bochum, Germany. Twenty healthy male students, (mean ± standard deviation; 24.2 ± 1.9 years) recruited via local advertising, were consecutively included. ANI values were continuously recorded. After resting, four stimuli were applied in a random order on the right forearm (unexpected and expected electrical pain, expected nonpainful and sham stimuli). Blinded volunteers were asked to rate all four stimuli on NRS. ANI means (0-100), amplitudes, maxima, minima and slopes with NRS pain intensity scores (0-10). Resting alert volunteers showed ANI values of 82.05 ± 10.71. ANI decreased after a random stimulus (maximal decrease of 25.0 ± 7.3%), but different kinds of stimuli evoked similar results. NRS scores (median; interquartiles) were significantly (P = 0.008) higher after expected (5.25; 3.5-6.75) compared with unexpected (4.50; 3.0-5.0) pain stimuli. No correlation was found between ANI and NRS. ANI did not allow a differentiation of painful, nonpainful or sham stimuli in alert volunteers. Therefore, ANI does not exclusively detect nociception, but may be modified by stress and emotion. Thus, we conclude that ANI is not a specific, robust measure for assessment of pain

  3. Pain management: a review of organisation models with integrated processes for the management of pain in adult cancer patients.

    Science.gov (United States)

    Brink-Huis, Anita; van Achterberg, Theo; Schoonhoven, Lisette

    2008-08-01

    This paper reports a review of the literature conducted to identify organisation models in cancer pain management that contain integrated care processes and describe their effectiveness. Pain is experienced by 30-50% of cancer patients receiving treatment and by 70-90% of those with advanced disease. Efforts to improve pain management have been made through the development and dissemination of clinical guidelines. Early improvements in pain management were focussed on just one or two single processes such as pain assessment and patient education. Little is known about organisational models with multiple integrated processes throughout the course of the disease trajectory and concerning all stages of the care process. Systematic review. The review involved a systematic search of the literature, published between 1986-2006. Subject-specific keywords used to describe patients, disease, pain management interventions and integrated care processes, relevant for this review were selected using the thesaurus of the databases. Institutional models, clinical pathways and consultation services are three alternative models for the integration of care processes in cancer pain management. A clinical pathway is a comprehensive institutionalisation model, whereas a pain consultation service is a 'stand-alone' model that can be integrated in a clinical pathway. Positive patient and process outcomes have been described for all three models, although the level of evidence is generally low. Evaluation of the quality of pain management must involve standardised measurements of both patient and process outcomes. We recommend the development of policies for referrals to a pain consultation service. These policies can be integrated within a clinical pathway. To evaluate the effectiveness of pain management models standardised outcome measures are needed.

  4. Chronic stress moderates the impact of social exclusion on pain tolerance: an experimental investigation

    National Research Council Canada - National Science Library

    Pieritz K; Schäfer SJ; Strahler J; Rief W; Euteneuer F

    2017-01-01

    ... (ie, heat pain tolerance) and a sensory component of pain (ie, heat pain intensity). Whether a potential effect may be moderated by chronic life stress, social status, or social support was further examined...

  5. Influence of experimental pain on the perception of action capabilities and performance of a maximal single-leg hop.

    Science.gov (United States)

    Deschamps, Thibault; Hug, François; Hodges, Paul W; Tucker, Kylie

    2014-03-01

    Changes in an individual's state-for example, anxiety/chronic pain-can modify the perception of action capabilities and physical task requirements. In parallel, considerable literature supports altered motor performance during both acute and chronic pain. This study aimed to determine the effect of experimental pain on perception of action capabilities and performance of a dynamic motor task. Performance estimates and actual performance of maximal single-leg hops were recorded for both legs in 13 healthy participants before, during, and after an episode of acute pain induced by a single bolus injection of hypertonic saline into vastus lateralis of 1 leg, with the side counterbalanced among participants. Both estimation of performance and actual performance were smaller (P action-scaled relationship between perception and ability during acute pain. This study demonstrates that the relationship between perceived physical ability and actual performance is effectively updated during acute muscle pain. This match between perceived ability and performance could be relevant during clinical pain assessment, with the potential to be a biomarker of transition from acute to chronic pain state. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. Stress and visceral pain: from animal models to clinical therapies

    Science.gov (United States)

    Larauche, Muriel; Mulak, Agata; Taché, Yvette

    2011-01-01

    Epidemiological studies have implicated stress (psychosocial and physical) as a trigger of first onset or exacerbation of irritable bowel syndrome (IBS) symptoms of which visceral pain is an integrant landmark. A number of experimental acute or chronic exteroceptive or interoceptive stressors induce visceral hyperalgesia in rodents although recent evidence also points to stress-related visceral analgesia as established in the somatic pain field. Underlying mechanisms of stress-related visceral hypersensitivity may involve a combination of sensitization of primary afferents, central sensitization in response to input from the viscera and dysregulation of descending pathways that modulate spinal nociceptive transmission or analgesic response. Biochemical coding of stress involves the recruitment of corticotropin releasing factor (CRF) signaling pathways. Experimental studies established that activation of brain and peripheral CRF receptor subtype 1 plays a primary role in the development of stress-related delayed visceral hyperalgesia while subtype 2 activation induces analgesic response. In line with stress pathways playing a role in IBS, non-pharmacologic and pharmacologic treatment modalities aimed at reducing stress perception using a broad range of evidence-based mind-body interventions and centrally-targeted medications to reduce anxiety impact on brain patterns activated by visceral stimuli and dampen visceral pain. PMID:21575632

  7. Electrochemical desalination of bricks - Experimental and modeling

    DEFF Research Database (Denmark)

    Skibsted, Gry; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2015-01-01

    Chlorides, nitrates and sulfates play an important role in the salt-decay of porous materials in buildings and monuments. Electrochemical desalination is a technology able to remove salts from such porous materials in order to stop or prevent the decay. In this paper, experimental and numerical......-contaminated bricks with respect to the monovalent ions is discussed. Comparison between the experimental and the simulation results showed that the proposed numerical model is able to predict electrochemical desalination treatments with remarkable accuracy, and it can be used as a predictive tool...

  8. Development of a Rat Model of Mechanically Induced Tunable Pain and Associated Temporomandibular Joint Responses.

    Science.gov (United States)

    Kartha, Sonia; Zhou, Timothy; Granquist, Eric J; Winkelstein, Beth A

    2016-01-01

    Although mechanical overloading of the temporomandibular joint (TMJ) is implicated in TMJ osteoarthritis (OA) and orofacial pain, most experimental models of TMJ-OA induce only acute and resolving pain, which do not meaningfully simulate the pathomechanisms of TMJ-OA in patients with chronic pain. The aim of this study was to adapt an existing rat model of mechanically induced TMJ-OA, to induce persistent orofacial pain by altering only the jaw-opening force, and to measure the expression of common proxies of TMJ-OA, including degradation and inflammatory proteins, in the joint. TMJ-OA was mechanically induced in a randomized, prospective study using 2 magnitudes of opening loads in separate groups (ie.,. 2-N, 3.5-N and sham control [no load]). Steady mouth opening was imposed daily (60 minutes/day for 7 days) in female Holtzman rats, followed by 7 days of rest, and orofacial sensitivity was measured throughout the loading and rest periods. Joint structure and extent of degeneration were assessed at day 14 and expression of matrix metalloproteinase-13 (MMP-13), hypoxia-inducible factor-1α (HIF-1α), and tumor necrosis factor-α (TNF-α) in articular cartilage was evaluated by immunohistochemistry and quantitative densitometry methods at day 7 between the 2 loading and control groups. Statistical differences of orofacial sensitivity and chondrocyte expression between loading groups were computed and significance was set at a P value less than .05. Head-withdrawal thresholds for the 2 loading groups were significantly decreased during loading (P joints over those loaded by 2 N. Unlike a 2-N loading force, mechanical overloading of the TMJ using a 3.5-N loading force induced constant and nonresolving pain and the upregulation of inflammatory markers only in the 3.5-N group, suggesting that these markers could predict the maintenance of persistent orofacial pain. As such, the development of a tunable experimental TMJ-OA model that can separately induce acute or

  9. Psychological Factors in Chronic Pelvic Pain in Women: Relevance and Application of the Fear-Avoidance Model of Pain

    Science.gov (United States)

    Bishop, Mark D.

    2011-01-01

    Chronic pelvic pain in women is a debilitating, costly condition often treated by physical therapists. The etiology of this condition is multifactorial and poorly understood, given the complex interplay of muscles, bones, and soft tissue that comprise the pelvis. There are few guidelines directing treatment interventions for this condition. In the last decade, several investigators have highlighted the role of psychological variables in conditions such as vulvodynia and painful bladder syndrome. Pain-related fear is the focus of the fear-avoidance model (FAM) of pain, which theorizes that some people are more likely to develop and maintain pain after an injury because of their emotional and behavioral responses to pain. The FAM groups people into 2 classes on the basis of how they respond to pain: people who have low fear, confront pain, and recover from injury and people who catastrophize pain—a response that leads to avoidance/escape behaviors, disuse, and disability. Given the presence of pain-related cognitions in women with chronic pelvic pain, including hypervigilance, catastrophizing, and anxiety, research directed toward the application of the FAM to guide therapeutic interventions is warranted. Isolated segments of the FAM have been studied to theorize why traditional approaches (ie, medications and surgery) may not lead to successful outcomes. However, the explicit application of the FAM to guide physical therapy interventions for women with chronic pelvic pain is not routine. Integrating the FAM might direct physical therapists' clinical decision making on the basis of the pain-related cognitions and behaviors of patients. The aims of this article are to provide information about the FAM of musculoskeletal pain and to provide evidence for the relevance of the FAM to chronic pelvic pain in women. PMID:21835893

  10. Temporal divergence of changes in pain and pain-free grip strength after manual acupuncture or electroacupuncture: an experimental study in people with lateral epicondylalgia.

    Science.gov (United States)

    Jeon, Jaewon; Bussin, Erin; Scott, Alex

    2017-01-01

    The objective of this study was to examine, in individuals with lateral epicondylalgia (LE), the acute time course of acupuncture-induced hypoalgesia and change in pain-free grip strength (PFGS). This was an experimental study, conducted at a single research center in Vancouver, BC. Twenty-one participants with unilateral LE lasting more than 6 weeks duration were enrolled. Participants received a single treatment of acupuncture (either electroacupuncture, 10-30 Hz, or manual acupuncture, assigned randomly). The primary outcome measure was pain level (0-10) during tendon loading (while making a fist) immediately after treatment, and over a 72 h follow-up period. Secondary outcome measures included pain-free grip strength (N). There was a small but statistically significant reduction in participants' perceived pain level immediately after acupuncture (mean improvement of 1.2, 95% CI 0.45-1.9). This change in pain was not accompanied by a change in PFGS. No difference was observed between the two types of acupuncture at any time point. The use of acupuncture or electroacupuncture, as administered in the current study, is unlikely to acutely enhance the ability of people with LE to engage in pain-free rehabilitation exercise. Trial registration Registered February 25, 2015. ISRCTN14667535, http://www.isrctn.com/ISRCTN14667535.

  11. Peripheral and central neuroinflammatory changes and pain behaviours in an animal model of multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Samuel Shaw Duffy

    2016-09-01

    Full Text Available Pain is a widespread and debilitating symptom of multiple sclerosis (MS, a chronic inflammatory demyelinating disease of the central nervous system. Although central neuroinflammation and demyelination have been implicated in MS-related pain, the contribution of peripheral and central mechanisms during different phases of the disease remains unclear. In this study, we used the animal model experimental autoimmune encephalomyelitis (EAE to examine both stimulus-evoked and spontaneous pain behaviours, and neuroinflammatory changes, over the course of chronic disease. We found that mechanical allodynia of the hind paw preceded the onset of clinical EAE, but was unmeasurable at clinical peak. This mechanical hypersensitivity coincided with increased microglial activation confined to the dorsal horn of the spinal cord. The development of facial mechanical allodynia also emerged in pre-clinical EAE, persisted at the clinical peak, and corresponded with pathology of the peripheral trigeminal afferent pathway. This included T cell infiltration, which arose prior to overt central lesion formation, and specific damage to myelinated neurons during the clinical peak. Measurement of spontaneous pain using the mouse grimace scale, a facial expression-based coding system, showed increased facial grimacing in mice with EAE during clinical disease. This was associated with multiple peripheral and central neuroinflammatory changes including a decrease in myelinating oligodendrocytes, increased T cell infiltration and macrophage/microglia and astrocyte activation. Overall, these findings suggest that different pathological mechanisms may underlie stimulus-evoked and spontaneous pain in EAE, and that these behaviours predominate in unique stages of the disease.

  12. Pain expressiveness and altruistic behavior: an exploration using agent-based modeling.

    Science.gov (United States)

    de C Williams, Amanda C; Gallagher, Elizabeth; Fidalgo, Antonio R; Bentley, Peter J

    2016-03-01

    Predictions which invoke evolutionary mechanisms are hard to test. Agent-based modeling in artificial life offers a way to simulate behaviors and interactions in specific physical or social environments over many generations. The outcomes have implications for understanding adaptive value of behaviors in context. Pain-related behavior in animals is communicated to other animals that might protect or help, or might exploit or predate. An agent-based model simulated the effects of displaying or not displaying pain (expresser/nonexpresser strategies) when injured and of helping, ignoring, or exploiting another in pain (altruistic/nonaltruistic/selfish strategies). Agents modeled in MATLAB interacted at random while foraging (gaining energy); random injury interrupted foraging for a fixed time unless help from an altruistic agent, who paid an energy cost, speeded recovery. Environmental and social conditions also varied, and each model ran for 10,000 iterations. Findings were meaningful in that, in general, contingencies that evident from experimental work with a variety of mammals, over a few interactions, were replicated in the agent-based model after selection pressure over many generations. More energy-demanding expression of pain reduced its frequency in successive generations, and increasing injury frequency resulted in fewer expressers and altruists. Allowing exploitation of injured agents decreased expression of pain to near zero, but altruists remained. Decreasing costs or increasing benefits of helping hardly changed its frequency, whereas increasing interaction rate between injured agents and helpers diminished the benefits to both. Agent-based modeling allows simulation of complex behaviors and environmental pressures over evolutionary time.

  13. Does experimental low back pain change posteroanterior lumbar spinal stiffness and trunk muscle activity? A randomized crossover study.

    Science.gov (United States)

    Wong, Arnold Y L; Parent, Eric C; Prasad, Narasimha; Huang, Christopher; Chan, K Ming; Kawchuk, Gregory N

    2016-05-01

    While some patients with low back pain demonstrate increased spinal stiffness that decreases as pain subsides, this observation is inconsistent. Currently, the relation between spinal stiffness and low back pain remains unclear. This study aimed to investigate the effects of experimental low back pain on temporal changes in posteroanterior spinal stiffness and concurrent trunk muscle activity. In separate sessions five days apart, nine asymptomatic participants received equal volume injections of hypertonic or isotonic saline in random order into the L3-L5 interspinous ligaments. Pain intensity, spinal stiffness (global and terminal stiffness) at the L3 level, and the surface electromyographic activity of six trunk muscles were measured before, immediately after, and 25-minute after injections. These outcome measures under different saline conditions were compared by generalized estimating equations. Compared to isotonic saline injections, hypertonic saline injections evoked significantly higher pain intensity (mean difference: 5.7/10), higher global (mean difference: 0.73N/mm) and terminal stiffness (mean difference: 0.58N/mm), and increased activity of four trunk muscles during indentation (Ppain subsided. While previous clinical research reported inconsistent findings regarding the association between spinal stiffness and low back pain, our study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle co-contraction during indentation, which helps explain the temporal relation between spinal stiffness and low back pain observed in some clinical studies. Our results substantiate the role of spinal stiffness assessments in monitoring back pain progression. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Center of Pressure Displacement of Standing Posture during Rapid Movements Is Reorganised Due to Experimental Lower Extremity Muscle Pain.

    Directory of Open Access Journals (Sweden)

    Shinichiro Shiozawa

    Full Text Available Postural control during rapid movements may be impaired due to musculoskeletal pain. The purpose of this study was to investigate the effect of experimental knee-related muscle pain on the center of pressure (CoP displacement in a reaction time task condition.Nine healthy males performed two reaction time tasks (dominant side shoulder flexion and bilateral heel lift before, during, and after experimental pain induced in the dominant side vastus medialis or the tibialis anterior muscles by hypertonic saline injections. The CoP displacement was extracted from the ipsilateral and contralateral side by two force plates and the net CoP displacement was calculated.Compared with non-painful sessions, tibialis anterior muscle pain during the peak and peak-to-peak displacement for the CoP during anticipatory postural adjustments (APAs of the shoulder task reduced the peak-to-peak displacement of the net CoP in the medial-lateral direction (P<0.05. Tibialis anterior and vastus medialis muscle pain during shoulder flexion task reduced the anterior-posterior peak-to-peak displacement in the ipsilateral side (P<0.05.The central nervous system in healthy individuals was sufficiently robust in maintaining the APA characteristics during pain, although the displacement of net and ipsilateral CoP in the medial-lateral and anterior-posterior directions during unilateral fast shoulder movement was altered.

  15. Experimental Animal Models in Periodontology: A Review

    Science.gov (United States)

    Struillou, Xavier; Boutigny, Hervé; Soueidan, Assem; Layrolle, Pierre

    2010-01-01

    In periodontal research, animal studies are complementary to in vitro experiments prior to testing new treatments. Animal models should make possible the validation of hypotheses and prove the safety and efficacy of new regenerating approaches using biomaterials, growth factors or stem cells. A review of the literature was carried out by using electronic databases (PubMed, ISI Web of Science). Numerous animal models in different species such as rats, hamsters, rabbits, ferrets, canines and primates have been used for modeling human periodontal diseases and treatments. However, both the anatomy and physiopathology of animals are different from those of humans, making difficult the evaluation of new therapies. Experimental models have been developed in order to reproduce major periodontal diseases (gingivitis, periodontitis), their pathogenesis and to investigate new surgical techniques. The aim of this review is to define the most pertinent animal models for periodontal research depending on the hypothesis and expected results. PMID:20556202

  16. Observer influences on pain: an experimental series examining same-sex and opposite-sex friends, strangers, and romantic partners.

    Science.gov (United States)

    Edwards, Rhiannon; Eccleston, Christopher; Keogh, Edmund

    2017-05-01

    Despite the well-documented sex and gender differences, little is known about the relative impact of male-female social interactions on pain. Three experiments were conducted to investigate whether the type of interpersonal relationship men and women have with an observer affects how they respond to experimental pain. Study 1 recruited friends and strangers, study 2 examined the effects of same- and opposite-sex friends, whereas study 3 investigated the differences between opposite-sex friends and opposite-sex romantic partners. One hundred forty-four dyads were recruited (48 in each study). One person from each dyad completed 2 pain tasks, whereas the other person observed in silence. Overall, the presence of another person resulted in an increase in pain threshold and tolerance on the cold-pressor task and algometer. The sex status of the dyads also had a role, but only within the friendship groups. In particular, male friends had the most pronounced effect on men's pain, increasing pain tolerance. We suggest that the presence of an observer, their sex, and the nature of the participant-observer relationship all influence how pain is reported. Further research should focus on dyadic relationships, and their influence on how men and women report and communicate pain in specific contexts.

  17. Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication.

    Science.gov (United States)

    Pasinato, Fernanda; Santos-Couto-Paz, Clarissa C; Zeredo, Jorge Luis Lopes; Macedo, Sergio Bruzadelli; Corrêa, Eliane C R

    2016-12-01

    The aim of this study was to verify the effects of induced masseter-muscle pain on the amplitude of muscle activation, symmetry and coactivation of jaw- and neck-muscles during mastication. Twenty-eight male volunteers, mean age±SD 20.6±2.0years, participated in this study. Surface electromyography of the masseter and sternocleidomastoid (SCM) muscles was performed bilaterally during mastication of a gummy candy before and after injections of monosodium glutamate solution and isotonic saline solution. As a result, we observed a decrease in the amplitude of activation of the masseter muscle on the working side (p=0.009; d=0.34) and a reduction in the asymmetry between the working and the balancing side during mastication (p=0.007; d=0.38). No changes were observed either on the craniocervical electromyographic variables. In conclusion, experimentally induced pain reduced the masseter muscle activation on the working side, thereby reducing the physiological masseters' recruitment asymmetry between the two sides during mastication. No effects on SCM activity were detected. These results may partly explain the initial maladaptative changes underlying TMD conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Masticatory sensory-motor changes after an experimental chewing test influenced by pain catastrophizing and neck-pain-related disability in patients with headache attributed to temporomandibular disorders.

    Science.gov (United States)

    La Touche, Roy; Paris-Alemany, Alba; Gil-Martínez, Alfonso; Pardo-Montero, Joaquín; Angulo-Díaz-Parreño, Santiago; Fernández-Carnero, Josué

    2015-03-05

    Recent research has shown a relationship of craniomandibular disability with neck-pain-related disability has been shown. However, there is still insufficient information demonstrating the influence of neck pain and disability in the sensory-motor activity in patients with headache attributed to temporomandibular disorders (TMD). The purpose of this study was to investigate the influence of neck-pain-related disability on masticatory sensory-motor variables. An experimental case-control study investigated 83 patients with headache attributed to TMD and 39 healthy controls. Patients were grouped according to their scores on the neck disability index (NDI) (mild and moderate neck disability). Initial assessment included the pain catastrophizing scale and the Headache Impact Test-6. The protocol consisted of baseline measurements of pressure pain thresholds (PPT) and pain-free maximum mouth opening (MMO). Individuals were asked to perform the provocation chewing test, and measurements were taken immediately after and 24 hours later. During the test, patients were assessed for subjective feelings of fatigue (VAFS) and pain intensity. VAFS was higher at 6 minutes (mean 51.7; 95% CI: 50.15-53.26) and 24 hours after (21.08; 95% CI: 18.6-23.5) for the group showing moderate neck disability compared with the mild neck disability group (6 minutes, 44.16; 95% CI 42.65-45.67/ 24 hours after, 14.3; 95% CI: 11.9-16.7) and the control group. The analysis shows a decrease in the pain-free MMO only in the group of moderate disability 24 hours after the test. PPTs of the trigeminal region decreased immediately in all groups, whereas at 24 hours, a decrease was observed in only the groups of patients. PPTs of the cervical region decreased in only the group with moderate neck disability 24 hours after the test. The strongest negative correlation was found between pain-free MMO immediately after the test and NDI in both the mild (r = -0.49) and moderate (r = -0.54) neck disability

  19. Investigating Circadian Rhythmicity in Pain Sensitivity Using a Neural Circuit Model for Spinal Cord Processing of Pain

    DEFF Research Database (Denmark)

    Crodelle, Jennifer; Piltz, Sofia Helena; Booth, Victoria

    2017-01-01

    the resultant pain signal. The differential equation models describe the average firing rates of excitatory and inhibitory interneuron populations, as well as the wide dynamic range (WDR) neurons whose output correlates with the pain signal. The temporal profile of inputs on the different afferent nerve fibers...

  20. Pain management: a review of organisation models with integrated processes for the management of pain in adult cancer patients.

    NARCIS (Netherlands)

    Brink-Huis, A.; Achterberg, T. van; Schoonhoven, L.J.

    2008-01-01

    AIMS AND OBJECTIVES: This paper reports a review of the literature conducted to identify organisation models in cancer pain management that contain integrated care processes and describe their effectiveness. BACKGROUND: Pain is experienced by 30-50% of cancer patients receiving treatment and by

  1. Experimental superficial candidiasis on tissue models.

    Science.gov (United States)

    Jayatilake, J A M S; Samaranayake, L P

    2010-07-01

    Candida species are common pathogens causing superficial mycoses primarily affecting the mucosa and the skin in humans. Crucial steps during pathogenesis of superficial candidiasis comprise fungal adhesion, colonisation and subsequent penetration of the respective tissues. Exploring these pathological events and perhaps fungal and tissue responses towards drug treatment is imperative in the management of this infection. Unfortunately, pathological biopsies of superficial candidiasis do not exhibit the early changes in the host-pathogen interaction as the tissues are already invaded by the fungi. In vivo experimental assessments of pathological processes of superficial candidiasis are also limited because of the difficulties in providing reproducible and comparable conditions in the host environment. Conversely, in vitro models have helped studying fungal-host interactions under more defined and controlled conditions. Some common in vitro models used to simulate superficial candidiasis are chick chorioallantoic membrane, mucosal explants and single layer or multiple layer cell cultures. Interestingly, these experimental approaches share advantages as well as disadvantages when compared with in vivo conditions. Hence, this review intends to discuss about the experimental superficial candidiasis produced in various tissue models and their advantages as well as disadvantages with a particular reference to further improvement of validity and reliability of such experiments.

  2. Seclazone Reactor Modeling And Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Osinga, T. [ETH-Zuerich (Switzerland); Olalde, G. [CNRS Odeillo (France); Steinfeld, A. [PSI and ETHZ (Switzerland)

    2005-03-01

    A numerical model is formulated for the SOLZINC solar chemical reactor for the production of Zn by carbothermal reduction of ZnO. The model involves solving, by the finite-volume technique, a 1D unsteady state energy equation that couples heat transfer to the chemical kinetics for a shrinking packed bed exposed to thermal radiation. Validation is accomplished by comparison with experimentally measured temperature profiles and Zn production rates as a function of time, obtained for a 5-kW solar reactor tested at PSI's solar furnace. (author)

  3. Beyond the standard model, experimental summary

    CERN Document Server

    McPherson, R A

    2003-01-01

    An overview of experimental results in searches for physics beyond the Standard Model is presented. It is impossible to cover all topics in this field, so a set of examples is used to highlight the scope and breadth of the results. Selected topics include searches for compositeness, flavour changing neutral currents, SUSY, exotic Higgs particles, low scale gravity in extra dimensions, and non commutative geometry. Current results are presented from the LEP, Tevatron Run I, and HERA I experiments. No convincing evidence for physics beyond the Standard Model has been observed. Prospects for ongoing and upcoming experiments are discussed. (40 refs).

  4. Phantom limb pain: an energy/trauma model.

    Science.gov (United States)

    Leskowitz, Eric

    2014-01-01

    Phantom limb pain (PLP) is a form of chronic neuropathic pain that responds poorly to treatment interventions derived from the neuroanatomic understanding of pain and analgesia. Several new psychological and behavioral treatments that have proven more effective have been explained by invoking neural plasticity as their mechanism of action. Other novel treatments that are based on an "energy medicine" model also appear to be quite effective, especially when addressing the psychological trauma of the amputation itself, a factor that is generally overlooked in the standard surgical approach to limb amputation. A speculative trauma/energy model for the etiology of PLP is proposed. This model is developed in some detail, and its utility in explaining several anomalous aspects of PLP, as well as the clinical efficacy of energy therapies, is outlined. This model is proposed as a step in the development of simple and effective energy/trauma treatment protocols for this widespread and largely treatment-resistant disorder. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Experimental in Vivo Models of Candidiasis

    Directory of Open Access Journals (Sweden)

    Esther Segal

    2018-02-01

    Full Text Available Candidiasis is a multifaceted fungal disease including mucosal-cutaneous, visceral, and disseminated infections caused by yeast species of the genus Candida. Candida infections are among the most common human mycoses. Candida species are the third to fourth most common isolates from bloodstream infections in neutropenic or immunocompromised hospitalized patients. The mucosal-cutaneous forms—particularly vaginal infections—have a high prevalence. Vaginitis caused by Candida species is the second most common vaginal infection. Hence, candidiasis is a major subject for research, including experimental in vivo models to study pathogenesis, prevention, or therapy of the disease. The following review article will focus on various experimental in vivo models in different laboratory animals, such as mammals (mice, rats, rabbits, the fruit fly–Drosophila melanogaster, the larvae of the moth Galleria mellonella, or the free-living nematode Caenorhabditis elegans. The review will describe the induction of the different clinical forms of candidiasis in the various models and the validity of such models in mimicking the human clinical situations. The use of such models for the assessment of antifungal drugs, evaluation of potential vaccines to protect before candidiasis, exploration of Candida virulence factors, and comparison of pathogenicity of different Candida species will be included in the review. All of the above will be reported as based on published studies of numerous investigators as well as on the research of the author and his group.

  6. Antihyperalgesic Effect of Hesperidin Improves with Diosmin in Experimental Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Azucena I. Carballo-Villalobos

    2016-01-01

    Full Text Available Neuropathic pain is caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or central nervous system. In this study, we investigated the hesperidin antihyperalgesic effects alone or combined with diosmin in a model of neuropathic pain to corroborate a possible synergistic antinociceptive activity. Mechanical and thermal hyperalgesia were assessed in the aesthesiometer and plantar tests, respectively, after chronic constriction injury (CCI model in rats receiving hesperidin (HS, 5 doses from 10 to 1000 mg/kg alone or combined with diosmin (DS, 10 and 100 mg/kg in comparison to gabapentin (31.6 mg/kg. UHPLC-MS analysis of cerebral samples was used to recognize the central concentrations of these flavonoids. Participation of different receptors was also investigated in the presence of haloperidol, bicuculline, and naloxone antagonists. Acute hesperidin administration significantly decreased mechanical and thermal hyperalgesia in CCI rats. Antihyperalgesic response of hesperidin, improved by a combination with diosmin (DS10/HS100 in both stimuli, was blockaded by haloperidol, bicuculline, and naloxone, but not WAY100635, antagonists. Both flavonoids were detected in brain samples. In conclusion, hesperidin alone and combined with diosmin produces antihyperalgesic response in the CCI model in rats. Antihyperalgesic effect of DS10/HS100 combination involves central activity partially modulated by D2, GABAA, and opioids, but not by 5-HT1A, receptors.

  7. Analgesic and antihyperalgesic effects of melatonin in a human inflammatory pain model

    DEFF Research Database (Denmark)

    Andersen, Lars P H; Gögenur, Ismail; Fenger, Andreas Q

    2015-01-01

    Antinociceptive effects of melatonin have been documented in a wide range of experimental animal models. The aim of this study was to investigate the analgesic, antihyperalgesic, and anti-inflammatory properties of melatonin using a validated burn injury (BI) model in healthy male volunteers...... by a computerized contact thermode (47.0°C, 420 seconds, 5.0 × 2.5 cm). Pain ratings during the BI and quantitative sensory testing at baseline and at 1, 2, 4, and 6 hours after the BI were performed. Quantitative sensory testing included assessments of secondary hyperalgesia areas, mechanical and thermal...... thresholds in the BI area, and pressure algometry. Furthermore, markers of inflammation, skin-reflectance spectrophotometry, and high-resolution ultrasonography were applied to measure skin erythema and dermal thickness in the BI area. Pain during the BI and secondary hyperalgesia areas were defined...

  8. Impact of Abuse on Adjustment and Chronic Pain Disability: A Structural Equation Model.

    Science.gov (United States)

    Mehta, Swati; Rice, Danielle; Chan, Alan; Shapiro, Allan P; Sequeira, Keith; Teasell, Robert W

    2017-08-01

    Sexual abuse, state and trait psychosocial factors, pain intensity, and pain-related disability have been shown to be correlated among individuals with chronic pain. However, the interacting relationships among these factors are poorly understood. The current study aims to test model which examines the effect of abuse, state and trait psychosocial factors, and pain intensity on pain-related disability among individuals with chronic pain. In total, 229 participants diagnosed with chronic pain were recruited from a specialist chronic pain hospital in London, Ontario. Participants completed self-report measures related to sexual abuse history, pain intensity, personality (anxiety sensitivity, experiential avoidance, perfectionism), and adjustment (depression, anxiety, disability, maladaptive worrying). A path analysis was used to test the relationship among these variables. The model provided a close fit to the data (χ21=17.02; P=0.71; root-mean-square error of approximation=0.00; normal fit index=0.97; comparative fit index=1.0). The model demonstrates the direct and indirect effects of childhood sexual abuse on state and trait psychosocial factors among individuals with chronic pain. Pain anxiety, maladaptive worrying, and pain intensity were the main determinants of pain-related disability. The current model has important implications in understanding the interplay of factors involved in adjustment of individuals with chronic pain. Sexual abuse did not have a direct effect on pain-related disability. However, indirect effects through other psychosocial factors were demonstrated.

  9. Endometriose: modelo experimental em ratas Endometriosis: experimental model in rats

    Directory of Open Access Journals (Sweden)

    Eduardo Schor

    1999-06-01

    Full Text Available Objetivo: divulgar a metodologia da indução de endometriose experimental em animais de laboratório. Método: utilizamos ratas albinas, virgens, adultas de aproximadamente três meses de idade, que foram inicialmente anestesiadas pelo éter etílico. Aberta a cavidade abdominal, identificamos os cornos uterinos e retiramos um fragmento de aproximadamente 4 cm do corno uterino direito. Esse fragmento foi mergulhado em solução fisiológica e sob lupa estereoscópica foi separado o endométrio do miométrio e feitos retângulos de aproximadamente 4 por 5 mm. Esses foram fixados por meio de fio de sutura, sobre vasos sangüíneos visíveis a olho nu, na parede lateral do abdômen, tomando-se sempre o cuidado de manter a porção do endométrio livre voltada para a luz da cavidade abdominal. Após 21 dias os animais foram novamente operados para verificarmos o tamanho dos implantes e para retirada do endométrio ectópico para análise histológica. Resultados: macroscopicamente observamos crescimento significativo dos implantes endometriais. Ao exame microscópico pudemos observar a presença de epitélio glandular e estroma semelhantes ao do endométrio tópico. Conclusões: o modelo utilizado reproduz a doença, em ratas, sendo método auxiliar de valia para estudar esta afecção, principalmente a ação de medicamentos sobre esses implantes.Purpose: to demonstrate the experimental endometriosis induction in animals. Method: we used adult female Wistar rats weighing 200 - 250 g anesthetized with ethyl ether to open the abdominal cavity. After identifying the uterine horns, we removed an approximately 4 cm fragment from the right uterine horn. This fragment was placed in physiological saline and, with the aid of a stereoscopic magnifying glass, the endometrium was separated from the myometrium and cut into rectangles of approximately 4 x 5 mm. These rectangles were fastened to the lateral abdominal wall near great blood vessels, taking care

  10. 1987 Volvo award in clinical sciences. A new clinical model for the treatment of low-back pain.

    Science.gov (United States)

    Waddell, G

    1987-09-01

    Because there is increasing concern about low-back disability and its current medical management, this analysis attempts to construct a new theoretic framework for treatment. Observations of natural history and epidemiology suggest that low-back pain should be a benign, self-limiting condition, that low back-disability as opposed to pain is a relatively recent Western epidemic, and that the role of medicine in that epidemic must be critically examined. The traditional medical model of disease is contrasted with a biopsychosocial model of illness to analyze success and failure in low-back disorders. Studies of the mathematical relationship between the elements of illness in chronic low-back pain suggest that the biopsychosocial concept can be used as an operational model that explains many clinical observations. This model is used to compare rest and active rehabilitation for low-back pain. Rest is the commonest treatment prescribed after analgesics but is based on a doubtful rationale, and there is little evidence of any lasting benefit. There is, however, little doubt about the harmful effects--especially of prolonged bed rest. Conversely, there is no evidence that activity is harmful and, contrary to common belief, it does not necessarily make the pain worse. Experimental studies clearly show that controlled exercises not only restore function, reduce distress and illness behavior, and promote return to work, but actually reduce pain. Clinical studies confirm the value of active rehabilitation in practice. To achieve the goal of treating patients rather than spines, we must approach low-back disability as an illness rather than low-back pain as a purely physical disease. We must distinguish pain as a purely the symptoms and signs of distress and illness behavior from those of physical disease, and nominal from substantive diagnoses. Management must change from a negative philosophy of rest for pain to more active restoration of function. Only a new model and

  11. Experimental animal modelling for TB vaccine development

    Directory of Open Access Journals (Sweden)

    Pere-Joan Cardona

    2017-03-01

    Full Text Available Research for a novel vaccine to prevent tuberculosis is an urgent medical need. The current vaccine, BCG, has demonstrated a non-homogenous efficacy in humans, but still is the gold standard to be improved upon. In general, the main indicator for testing the potency of new candidates in animal models is the reduction of the bacillary load in the lungs at the acute phase of the infection. Usually, this reduction is similar to that induced by BCG, although in some cases a weak but significant improvement can be detected, but none of candidates are able to prevent establishment of infection. The main characteristics of several laboratory animals are reviewed, reflecting that none are able to simulate the whole characteristics of human tuberculosis. As, so far, no surrogate of protection has been found, it is important to test new candidates in several models in order to generate convincing evidence of efficacy that might be better than that of BCG in humans. It is also important to investigate the use of “in silico” and “ex vivo” models to better understand experimental data and also to try to replace, or at least reduce and refine experimental models in animals.

  12. Nonlinear hierarchical modeling of experimental infection data.

    Science.gov (United States)

    Singleton, Michael D; Breheny, Patrick J

    2016-08-01

    In this paper, we propose a nonlinear hierarchical model (NLHM) for analyzing longitudinal experimental infection (EI) data. The NLHM offers several improvements over commonly used alternatives such as repeated measures analysis of variance (RM-ANOVA) and the linear mixed model (LMM). It enables comparison of relevant biological properties of the course of infection including peak intensity, duration and time to peak, rather than simply comparing mean responses at each observation time. We illustrate the practical benefits of this model and the insights it yields using data from experimental infection studies on equine arteritis virus. Finally, we demonstrate via simulation studies that the NLHM substantially reduces bias and improves the power to detect differences in relevant features of the infection response between two populations. For example, to detect a 20% difference in response duration between two groups (n=15) in which the peak time and peak intensity were identical, the RM-ANOVA test had a power of just 11%, and LMM a power of just 12%. By comparison, the nonlinear model we propose had a power of 58% in the same scenario, while controlling the Type I error rate better than the other two methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Models for Experimental High Density Housing

    Science.gov (United States)

    Bradecki, Tomasz; Swoboda, Julia; Nowak, Katarzyna; Dziechciarz, Klaudia

    2017-10-01

    The article presents the effects of research on models of high density housing. The authors present urban projects for experimental high density housing estates. The design was based on research performed on 38 examples of similar housing in Poland that have been built after 2003. Some of the case studies show extreme density and that inspired the researchers to test individual virtual solutions that would answer the question: How far can we push the limits? The experimental housing projects show strengths and weaknesses of design driven only by such indexes as FAR (floor attenuation ratio - housing density) and DPH (dwellings per hectare). Although such projects are implemented, the authors believe that there are reasons for limits since high index values may be in contradiction to the optimum character of housing environment. Virtual models on virtual plots presented by the authors were oriented toward maximising the DPH index and DAI (dwellings area index) which is very often the main driver for developers. The authors also raise the question of sustainability of such solutions. The research was carried out in the URBAN model research group (Gliwice, Poland) that consists of academic researchers and architecture students. The models reflect architectural and urban regulations that are valid in Poland. Conclusions might be helpful for urban planners, urban designers, developers, architects and architecture students.

  14. Effects of Hemibridge with Ball and Balloon Exercise on Forced Expiratory Volume and Pain in Patients with Chronic Low Back Pain: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Jorida Fernandes

    2017-08-01

    Full Text Available Background and objectives: Suboptimal breathing patterns and impairments of posture and trunk stability are often associated with musculoskeletal complaints such as low back pain. Respiration is also affected by poor neuromuscular control of core muscles. Immediate effects of hemibridge with ball and balloon exercise has been studied on chronic pain in athlete population. Objective: To evaluate the effects of hemibridge with ball and balloon exercise on pain, forced expiratory volume and functional abilities in patients with chronic low back pain using Visual Analogue Scale (VAS, Forced Expiratory Volume (FEV and Modified Oswestry Disability Questionnaire (MODQ. Methods: The present experimental study was conducted among 30 participants between the age of 21 to 55 years with chronic non-specific LBP. The participants were given a hemibridge with ball and balloon exercise. Pre-interventional and 3rd day Post-interventional outcome measurements were taken using VAS, FEV1 and FEV6 and MODQ. Results: The difference between pre-and post of VAS was statistically highly significant (p=0.0001. The p value of FEV6 and MODQ by paired t test was statistically significant with p value of 0.02 and 0.0007 respectively. Conclusion: The study concludes that there is an immediate effect of hemibridge with ball and balloon exercise on pain, FEV6 and functional ability in patients with chronic LBP.

  15. A rat model of temporomandibular joint pain with histopathologic modifications.

    Science.gov (United States)

    Nicoll, Steven B; Hee, Christopher K; Davis, Martin B; Winkelstein, Beth A

    2010-01-01

    To develop a rat model of temporomandibular joint (TMJ) pain and to characterize in it the development and temporal response of behavioral hypersensitivity as well as to evaluate if and to what extent a loading protocol is associated with histological changes in the TMJ consistent with osteoarthritic pathology. A novel rat model of TMJ pain was developed using a noninvasive, mechanical loading protocol. Rats were exposed to steady mouth-opening for 7 days (2 N force, 1 hour/day), and mechanical hyperalgesia (increased pain response) was measured during the loading period and for 14 days thereafter. Histological modifications in the joint cartilage were also evaluated. Outcomes for the mouth-opening exposure were compared to age-matched controls. Thresholds for evoking responses were compared using a ranked ANOVA with repeated measures. Increased mechanical hypersensitivity in the temporomandibular region developed during daily loading and persisted even after the termination of the loading protocol. Histologic characterization revealed thinning of the cartilaginous structures of the joint and irregular zonal cellular arrangements in the condylar cartilage of rats subjected to the daily loading protocol. The injury model presented here is the first to demonstrate mechanically-induced behavioral hypersensitivity accompanied by osteoarthritic pathology in the TMJ.

  16. Sleep Fragmentation Hypersensitizes Healthy Young Women to Deep and Superficial Experimental Pain.

    Science.gov (United States)

    Iacovides, Stella; George, Kezia; Kamerman, Peter; Baker, Fiona C

    2017-07-01

    The effect of sleep deprivation on pain sensitivity has typically been studied using total and partial sleep deprivation protocols. These protocols do not mimic the fragmented pattern of sleep disruption usually observed in individuals with clinical pain conditions. Therefore, we conducted a controlled experiment to investigate the effect of sleep fragmentation on pain perception (deep pain: forearm muscle ischemia, and superficial pain: graded pin pricks applied to the skin) in 11 healthy young women after 2 consecutive nights of sleep fragmentation, compared with a normal night of sleep. Compared with normal sleep, sleep fragmentation resulted in significantly poorer sleep quality, morning vigilance, and global mood. Pin prick threshold decreased significantly (increased sensitivity), as did habituation to ischemic muscle pain (increased sensitivity), over the course of the 2 nights of sleep fragmentation compared with the night of normal sleep. Sleep fragmentation did not increase the maximum pain intensity reported during muscle ischemia (no increase in gain), and nor did it increase the number of spontaneous pains reported by participants. Our data show that sleep fragmentation in healthy, young, pain-free women increases pain sensitivity in superficial and deep tissues, indicating a role for sleep disruption, through sleep fragmentation, in modulating pain perception. Our findings that pain-free, young women develop hyperalgesia to superficial and deep muscle pain after short-term sleep disruption highlight the need for effective sleep management strategies in patients with pain. Findings also suggest the possibility that short-term sleep disruption associated with recurrent acute pain could contribute to increased risk for future chronic pain conditions. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  17. Effects of experimental tooth clenching on pain and intramuscular release of 5-HT and glutamate in patients with myofascial TMD.

    Science.gov (United States)

    Dawson, Andreas; Ghafouri, Bijar; Gerdle, Björn; List, Thomas; Svensson, Peter; Ernberg, Malin

    2015-08-01

    It has been suggested that tooth clenching may be associated with local metabolic changes, and is a risk factor for myofascial temporomandibular disorders (M-TMD). This study investigated the effects of experimental tooth clenching on the levels of 5-HT, glutamate, pyruvate, and lactate, as well as on blood flow and pain intensity, in the masseter muscles of M-TMD patients. Fifteen patients with M-TMD and 15 pain-free controls participated. Intramuscular microdialysis was performed to collect 5-HT, glutamate, pyruvate, and lactate and to assess blood flow. Two hours after the insertion of a microdialysis catheter, participants performed a 20-minute repetitive tooth clenching task (50% of maximal voluntary contraction). Pain intensity was measured throughout. A significant effect of group (Prelease of other algesic substances that may cause pain.

  18. Modeling of Experimental Atherosclerotic Plaque Delamination.

    Science.gov (United States)

    Leng, Xiaochang; Chen, Xin; Deng, Xiaomin; Sutton, Michael A; Lessner, Susan M

    2015-12-01

    A cohesive zone model (CZM) approach is applied to simulate atherosclerotic plaque delamination experiments in mouse abdominal aorta specimens. A three-dimensional finite element model is developed for the experiments. The aortic wall is treated as a fiber-reinforced, highly deformable, incompressible material, and the Holzapfel-Gasser-Ogden (HGO) model is adopted for the aortic bulk material behavior. Cohesive elements are placed along the plaque-media interface along which delamination occurs. The 3D specimen geometry is created based on images from the experiments and certain simplifying approximations. A set of HGO and CZM parameter values is determined based on values suggested in the literature and through matching simulation predictions of the load vs. load-point displacement curve with experimental measurements for one loading-delamination-unloading cycle. Using this set of parameter values, simulation predictions for four other loading-delamination-unloading cycles are obtained, which show good agreement with experimental measurements. The findings of the current study demonstrate the applicability of the CZM approach in arterial tissue failure simulations.

  19. Superficial tension: experimental model with simple materials

    Directory of Open Access Journals (Sweden)

    Tintori Ferreira, María Alejandra

    2012-09-01

    Full Text Available In this work appears a didactic offer based on an experimental activity using materials of very low cost, orientated to achieving that the student understand and interpret the phenomenon of superficial tension together with the importance of the modeling in sciences. It has as principal aim of education bring the student over to the mechanics of the static fluids and the intermolecular forces, combining scientific contents with questions near to the student what provides an additional motivation to the reflection of the scientific investigation.

  20. A review of the evidence regarding associations between attachment theory and experimentally induced pain.

    Science.gov (United States)

    Meredith, Pamela Joy

    2013-04-01

    Theoretical and empirical evidence suggests that adult attachment and pain-related variables are predictably and consistently linked, and that understanding these links may guide pain intervention and prevention efforts. In general, insecure attachment has been portrayed as a risk factor, and secure attachment as a protective factor, for people with chronic pain conditions. In an effort to better understand the relationships among attachment and pain variables, these links have been investigated in pain-free samples using induced-pain techniques. The present paper reviews the available research linking adult attachment and laboratory-induced pain. While the diverse nature of the studies precludes definitive conclusions, together these papers offer support for associations between insecure attachment and a more negative pain experience. The evidence presented in this review highlights areas for further empirical attention, as well as providing some guidance for clinicians who may wish to employ preventive approaches and other interventions informed by attachment theory.

  1. Proteomic Identification of Altered Cerebral Proteins in the Complex Regional Pain Syndrome Animal Model

    Directory of Open Access Journals (Sweden)

    Francis Sahngun Nahm

    2014-01-01

    Full Text Available Background. Complex regional pain syndrome (CRPS is a rare but debilitating pain disorder. Although the exact pathophysiology of CRPS is not fully understood, central and peripheral mechanisms might be involved in the development of this disorder. To reveal the central mechanism of CRPS, we conducted a proteomic analysis of rat cerebrum using the chronic postischemia pain (CPIP model, a novel experimental model of CRPS. Materials and Methods. After generating the CPIP animal model, we performed a proteomic analysis of the rat cerebrum using a multidimensional protein identification technology, and screened the proteins differentially expressed between the CPIP and control groups. Results. A total of 155 proteins were differentially expressed between the CPIP and control groups: 125 increased and 30 decreased; expressions of proteins related to cell signaling, synaptic plasticity, regulation of cell proliferation, and cytoskeletal formation were increased in the CPIP group. However, proenkephalin A, cereblon, and neuroserpin were decreased in CPIP group. Conclusion. Altered expression of cerebral proteins in the CPIP model indicates cerebral involvement in the pathogenesis of CRPS. Further study is required to elucidate the roles of these proteins in the development and maintenance of CRPS.

  2. Autonomic nervous system and hypothalamic-pituitary-adrenal axis response to experimentally induced cold pain in adolescent non-suicidal self-injury--study protocol.

    Science.gov (United States)

    Koenig, Julian; Rinnewitz, Lena; Warth, Marco; Kaess, Michael

    2015-07-07

    Adolescent non-suicidal self-injury (NSSI) is associated with altered sensitivity to experimentally induced pain. Adolescents engaging in NSSI report greater pain threshold and pain tolerance, as well as lower pain intensity and pain unpleasantness compared to healthy controls. The experience of pain is associated with reactivity of both the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis. However, previous research has not yet systematically addressed differences in the physiological response to experimentally induced pain comparing adolescents with NSSI and age- and sex-matched healthy controls. Adolescents with NSSI and healthy controls undergo repeated painful stimulation with the cold pressor task. ANS activity is continuously recorded throughout the procedure to assess changes in heart rate and heart rate variability. Blood pressure is monitored and saliva is collected prior to and after nociceptive stimulation to assess levels of saliva cortisol. The study will provide evidence whether lower pain sensitivity in adolescents with NSSI is associated with blunted physiological and endocrinological responses to experimentally induced pain compared to healthy controls. Extending on the existing evidence on altered pain sensitivity in NSSI, measured by self-reports and behavioural assessments, this is the first study to take a systematic approach in evaluating the physiological response to experimentally induced pain in adolescent NSSI. Deutsche Register Klinischer Studien, Study ID: DRKS00007807; Trial Registration Date: 13.02.2015.

  3. Facial Pain Expression in Dementia : A Review of the Experimental and Clinical Evidence

    NARCIS (Netherlands)

    Lautenbacher, Stefan; Kunz, Miriam

    2017-01-01

    The analysis of the facial expression of pain promises to be one of the most sensitive tools for the detection of pain in patients with moderate to severe forms of dementia, who can no longer self-report pain. Fine-grain analysis using the Facial Action Coding System (FACS) is possible in research

  4. Characterisation of tramadol, morphine and tapentadol in an acute pain model in Beagle dogs.

    Science.gov (United States)

    Kögel, Babette; Terlinden, Rolf; Schneider, Johannes

    2014-05-01

    To evaluate the analgesic potential of the centrally acting analgesics tramadol, morphine and the novel analgesic tapentadol in a pre-clinical research model of acute nociceptive pain, the tail-flick model in dogs. Prospective part-randomized pre-clinical research trial. Fifteen male Beagle dogs (HsdCpb:DOBE), aged 12-15 months. On different occasions separated by at least 1 week, dogs received intravenous (IV) administrations of tramadol (6.81, 10.0 mg kg(-1) ), tapentadol (2.15, 4.64, 6.81 mg kg(-1) ) or morphine (0.464, 0.681, 1.0 mg kg(-1) ) with subsequent measurement of tail withdrawal latencies from a thermal stimulus (for each treatment n = 5). Blood samples were collected immediately after the pharmacodynamic measurements of tramadol to determine pharmacokinetics and the active metabolite O-demethyltramadol (M1). Tapentadol and morphine induced dose-dependent antinociception with ED50-values of 4.3 mg kg(-1) and 0.71 mg kg(-1) , respectively. In contrast, tramadol did not induce antinociception at any dose tested. Measurements of the serum levels of tramadol and the M1 metabolite revealed only marginal amounts of the M1 metabolite, which explains the absence of the antinociceptive effect of tramadol in this experimental pain model in dogs. Different breeds of dogs might not or only poorly respond to treatment with tramadol due to low metabolism of the drug. Tapentadol and morphine which act directly on μ-opioid receptors without the need for metabolic activation are demonstrated to induce potent antinociception in the experimental model used and should also provide a reliable pain management in the clinical situation. The non-opioid mechanisms of tramadol do not provide antinociception in this experimental setting. This contrasts to many clinical situations described in the literature, where tramadol appears to provide useful analgesia in dogs for post-operative pain relief and in more chronically pain states. © 2014 Association of Veterinary

  5. Muscle injury: review of experimental models.

    Science.gov (United States)

    Souza, Jaqueline de; Gottfried, Carmem

    2013-12-01

    Skeletal muscle is the most abundant tissue in the human body. Its main characteristic is the capacity to regenerate after injury independent of the cause of injury through a process called inflammatory response. Mechanical injuries are the most common type of the skeletal muscle injuries and are classified into one of three areas strain, contusion, and laceration. First, this review aims to describe and compare the main experimental methods that replicate the mechanical muscle injuries. There are several ways to replicate each kind of mechanical injury; there are, however, specific characteristics that must be taken into account when choosing the most appropriate model for the experiment. Finally, this review discusses the context of mechanical injury considering types, variability of methods, and the ability to reproduce injury models. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Testing a Model of Pain Appraisal and Coping in Children With Chronic Abdominal Pain

    OpenAIRE

    Walker, Lynn S.; Smith, Craig A.; Garber, Judy; Claar, Robyn Lewis

    2005-01-01

    This prospective study of children with recurrent abdominal pain (N = 133; ages 8–15 years) used path analysis to examine relations among dispositional pain beliefs and coping styles, cognitions and behavior related to a specific pain episode, and short- and long-term outcomes. Children believing they could not reduce or accept pain appraised their episode-specific coping ability as low and reported passive coping behavior. Dispositional passive coping had direct effects on both episode-speci...

  7. The association between dry needling-induced twitch response and change in pain and muscle function in patients with low back pain: a quasi-experimental study.

    Science.gov (United States)

    Koppenhaver, Shane L; Walker, Michael J; Rettig, Charles; Davis, Joel; Nelson, Chenae; Su, Jonathan; Fernández-de-Las-Peñas, Cesar; Hebert, Jeffrey J

    2017-06-01

    To investigate the relationship between dry needling-induced twitch response and change in pain, disability, nociceptive sensitivity, and lumbar multifidus muscle function, in patients with low back pain (LBP). Quasi-experimental study. Department of Defense Academic Institution. Sixty-six patients with mechanical LBP (38 men, 28 women, age: 41.3 [9.2] years). Dry needling treatment to the lumbar multifidus muscles between L3 and L5 bilaterally. Examination procedures included numeric pain rating, the Modified Oswestry Disability Index, pressure algometry, and real-time ultrasound imaging assessment of lumbar multifidus muscle function before and after dry needling treatment. Pain pressure threshold (PPT) was used to measure nocioceptive sensitivity. The percent change in muscle thickness from rest to contraction was calculated to represent muscle function. Participants were dichotomized and compared based on whether or not they experienced at least one twitch response on the most painful side and spinal level during dry needling. Participants experiencing local twitch response during dry needling exhibited greater immediate improvement in lumbar multifidus muscle function than participants who did not experience a twitch (thickness change with twitch: 12.4 [6]%, thickness change without twitch: 5.7 [11]%, mean difference adjusted for baseline value, 95%CI: 4.4 [1 to 8]%). However, this difference was not present after 1-week, and there were no between-groups differences in disability, pain intensity, or nociceptive sensitivity. The twitch response during dry needling might be clinically relevant, but should not be considered necessary for successful treatment. Published by Elsevier Ltd.

  8. Organ models in wound ballistics: experimental study.

    Science.gov (United States)

    Ozer, Mustafa Tahir; Oğünç, Gökhan; Eryilmaz, Mehmet; Yiğit, Taner; Menteş, Mustafa Oner; Dakak, Mehmet; Uzar, Ali Ihsan; Oner, Köksal

    2007-01-01

    Effects of various types and diameters of guns and related treatment principles are different. Our study was performed to experimentally demonstrate the effects of different gunshots in body tissues. 9x19 mm hand-gun and 7.62x51 mm G-3 infantry rifle were used in the study. Injury models were created through hand-gun and rifle shootings at isolated soft tissue, lower extremity, liver and intestine tissue simulants made of ballistic candle. High-speed cameras were used to capture 1000 frames per second. Images were examined and wound mechanisms were evaluated. It was observed that the colon content distributed more within the surrounding tissues by the rifle shootings comparing with hand-gun shootings and could be an infection source due to the large size of the cavity in the colon. Especially when the bullets hitting the bone were investigated, it was seen that much more tissue injury occurs with high speed bullets due to bullet deformation and fragmentation. However, no significant difference was found between the effect of hand-gun and rifle bullets passing through the extremity without hitting the bone. To know the type of the gun that caused the injury and its characteristics will allow to estimate severity and size of the injury before the treatment and to focus on different alternatives of treatment. Therefore, use of appropriate models is required in experimental studies.

  9. MOUSE MODELS FOR STUDYING PAIN IN SICKLE DISEASE: EFFECTS OF STRAIN, AGE, AND ACUTENESS

    OpenAIRE

    Cain, David M.; Vang, Derek; Simone, Donald A.; Hebbel, Robert P.; Gupta, Kalpna

    2011-01-01

    Clinical management of severe pain associated with sickle cell disease (SCD) remains challenging. Development of optimal therapy would be facilitated by use of murine model(s) with varying degrees of sickling and pain tests that are most sensitive to vasoocclusion. We found that young (≤3 month old) NY1DD and S+SAntilles mice (having modest and moderate sickle phenotype, respectively) exhibit evidence of deep tissue/musculoskeletal pain. Deep tissue pain and cold sensitivity in S+SAntilles mi...

  10. Intervertebral Foramen Injection of Ozone Relieves Mechanical Allodynia and Enhances Analgesic Effect of Gabapentin in Animal Model of Neuropathic Pain.

    Science.gov (United States)

    Luo, Wen-Jun; Yang, Fan; Yang, Fei; Sun, Wei; Zheng, Wei; Wang, Xiao-Liang; Wu, Fang-Fang; Wang, Jiang-Lin; Wang, Jia-Shuang; Guan, Su-Min; Chen, Jun

    2017-07-01

    In a 5-year follow-up study in a hospital in southern China, it was shown that intervertebral foramen (IVF) injection of ozone at the involved segmental levels could significantly alleviate paroxysmal spontaneous pain and mechanical allodynia in patients with chronic, intractable postherpetic neuralgia (PHN) and improve the quality of life. However, so far no proof-of-concept studies in animals have been available. This study was designed to investigate whether IVF ozone has an analgesic effect on animal models of neuropathic and inflammatory pain. Experimental trial in rats. Institute for Biomedical Sciences of Pain. By IVF injection, a volume of 50 µl containing 30 µg/mL ozone-oxygen mixture or 50 µl air was carried out on male Sprague-Dawley rats of naïve, inflammatory pain states produced by injections of either bee venom or complete Freud's adjuvant, and neuropathic pain state produced by spared nerve injury, respectively. The effects of IVF ozone on pain-related behaviors were evaluated for 2 weeks or one month. Then combined use of gabapentin (100 mg/1 kg body weight) with IVF ozone was evaluated in rats with neuropathic pain by intraperitoneal administration 5 days after the ozone treatment. Finally, the analgesic effects of another 4 drugs, AMD3100 (a CXCR4 antagonist), A-803467 (a selective Nav1.8 blocker), rapamycin (the mTOR inhibitor), and MGCD0103 (a selective histone deacetylase inhibitor) were evaluated for long term through IVF injection, respectively. (1) IVF injection of ozone at L4-5 was only effective in suppression of mechanical allodynia in rats with neuropathic pain but not with inflammatory pain; (2) the analgesic effects of IVF ozone lasted much longer (> 14 days) than other selective molecular target drugs (MGCD0103); (3) combined use of systemic gabapentin and IVF ozone produced a synergistic analgesic effect in rats with neuropathic pain. Evaluation of the possible analgesic effects of the intraplantar injection of ozone was not

  11. Getting a grip on pain : a model on pain and quality of life in adolescents with chronic pain

    NARCIS (Netherlands)

    V.P.B.M. Merlijn (Vivian)

    2004-01-01

    textabstractChronic pain in children and adolescents is increasingly recognized to occur. It often results in considerable functional disability and is a cause for health services utilisation. Chronic pain is known to have substantial impact on the quality of life of adolescents and their

  12. Evaluation of pain behavior and bone destruction in two arthritic models in guinea pig and rat.

    Science.gov (United States)

    Vermeirsch, Hilde; Biermans, Ria; Salmon, Philip L; Meert, Theo F

    2007-01-01

    The primary aim of the study was to describe and correlate pain behavior and changes in bone morphology in animal models of arthritis both in rats and guinea pigs. Either complete Freund's adjuvant (CFA) or mono-iodoacetate (MIA) solution was injected into the left knee joint to obtain a model for rheumatoid arthritis and osteoarthritis, respectively. Subsequently, animals were behaviorally tested during a period of 12 days after CFA injection and at least 19 days after MIA injection. During these observation periods increasing pain behavior was observed, characterized by decreased von Frey mechanical thresholds and weight bearing on the affected limb. In Hargreaves' paw flick test slightly increased thermal hypersensitivity was observed in some instances in guinea pigs. In rats there was also decreased limb-use during forced ambulation. To evaluate bone destruction mu-computed tomography scans of the arthritic knee were taken on the last experimental day. Different bone parameters indicative of osteolysis and decreased trabecular connectivity were significantly correlated with the observed pain behavior. Detailed description of morphological changes in arthritic joints better characterizes the different animal models and might add to the knowledge on the working mechanisms of analgesic compounds that have an influence on bone structures in arthritis.

  13. Transmission of risk from parents with chronic pain to offspring: an integrative conceptual model

    Science.gov (United States)

    Stone, Amanda L.; Wilson, Anna C.

    2017-01-01

    Offspring of parents with chronic pain are at increased risk for pain and adverse mental and physical health outcomes (Higgins et al, 2015). Although the association between chronic pain in parents and offspring has been established, few studies have addressed why or how this relation occurs. Identifying mechanisms for the transmission of risk that leads to the development of chronic pain in offspring is important for developing preventive interventions targeted to decrease risk for chronic pain and related outcomes (eg, disability and internalizing symptoms). This review presents a conceptual model for the intergenerational transmission of chronic pain from parents to offspring with the goal of setting an agenda for future research and the development of preventive interventions. Our proposed model highlights 5 potential mechanisms for the relation between parental chronic pain and pediatric chronic pain and related adverse outcomes: (1) genetics, (2) alterations in early neurobiological development, (3) pain-specific social learning, (4), general parenting and family health, and (5) exposure to stressful environment. In addition, the model presents 3 potential moderators for the relation between parent and child chronic pain: (1) the presence of chronic pain in a second parent, (2) timing, course, and location of parental chronic pain, and (3) offspring’s characteristics (ie, sex, developmental stage, race or ethnicity, and temperament). Such a framework highlights chronic pain as inherently familial and intergenerational, opening up avenues for new models of intervention and prevention that can be family centered and include at-risk children. PMID:27380502

  14. Experimental Basis for IED Particle Model

    Science.gov (United States)

    Zheng-Johansson, J.

    2009-05-01

    The internally electrodynamic (IED) particle model is built on three experimental facts: a) electric charges present in all matter particles, b) an accelerated charge generates electromagnetic (EM) waves by Maxwell's equations and Planck energy equation, and c) source motion gives Doppler effect. A set of well-kwon basic particle equations have been predicted based on first-principles solutions for IED particle (e.g. arxiv:0812.3951, J Phys CS128, 012019, 2008); the equations are long experimentally validated. A critical review of the key experiments suggests that the IED process underlies these equations not just sufficiently but also necessarily. E.g.: 1) A free IED electron solution is a plane wave ψ= Ce^i(kdX-φT) requisite for producing the diffraction fringe in a Davisson-Germer experiment, and of also all basic point-like attributes facilitated by a linear momentum kd and the model structure. It needs not further be a wave packet which produces not a diffraction fringe. 2)The radial partial EM waves, hence the total ψ, of an IED electron will, on both EM theory and experiment basis -not by assumption, enter two slits at the same time, as is requisite for an electron to interfere with itself as shown in double slit experiments. 3) On annihilation, an electron converts (from mass m) to a radiation energy φ without an acceleration which is externally observable and yet requisite by EM theory. So a charge oscillation of frequency φ and its EM waves must regularly present internal of a normal electron, whence the IED model.

  15. Pregabalin reduces acute inflammatory and persistent pain associated with nerve injury and cancer in rat models of orofacial pain.

    Science.gov (United States)

    Hummig, Wagner; Kopruszinski, Caroline Machado; Chichorro, Juliana Geremias

    2014-01-01

    To assess the analgesic effect of pregabalin in orofacial models of acute inflammatory pain and of persistent pain associated with nerve injury and cancer, and so determine its effectiveness in controlling orofacial pains having different underlying mechanisms. Orofacial capsaicin and formalin tests were employed in male Wistar rats to assess the influence of pregabalin (or vehicle) pretreatment in acute pain models, and the results from these experiments were analyzed by one-way analysis of variance (ANOVA) followed by Newman Keuls post-hoc test. Pregabalin (or vehicle) treatment was also tested on the facial heat hyperalgesia that was evaluated in rats receiving injection of the inflammatory irritant carrageenan into the upper lip, as well as after constriction of the infraorbital nerve (a model of trigeminal neuropathic pain), or after inoculation of tumor cells into the facial vibrissal pad; two-way repeated measures ANOVA followed by Newman-Keuls post-hoc test was used to analyze data from these experiments. Facial grooming induced by capsaicin was abolished by pretreatment with pregabalin at 10 and 30 mg/kg. However, pregabalin failed to modify the first phase of the formalin response, but reduced the second phase at both doses (10 and 30 mg/kg). In addition, treatment of rats with pregabalin reduced the heat hyperalgesia induced by carrageenan, as well as by nerve injury and facial cancer. Pregabalin produced a marked antinociceptive effect in rat models of facial inflammatory pain as well as in facial neuropathic and cancer pain models, suggesting that it may represent an important agent for the clinical control of orofacial pain.

  16. Comparison of burrowing and stimuli-evoked pain behaviors as end-points in rat models of inflammatory pain and peripheral neuropathic pain

    Directory of Open Access Journals (Sweden)

    Arjun eMuralidharan

    2016-05-01

    Full Text Available Establishment and validation of ethologically-relevant, non-evoked behavioral end-points as surrogate measures of spontaneous pain in rodent pain models has been proposed as a means to improve preclinical to clinical research translation in the pain field. Here, we compared the utility of burrowing behavior with hypersensitivity to applied mechanical stimuli for pain assessment in rat models of chronic inflammatory and peripheral neuropathic pain. Briefly, groups of male Sprague-Dawley rats were habituated to the burrowing environment and trained over a 5-day period. Rats that burrowed ≤450g of gravel on any two days of the individual training phase were excluded from the study. The remaining rats received either a unilateral intraplantar injection of Freund’s complete adjuvant (FCA or saline, or underwent unilateral chronic constriction injury (CCI of the sciatic nerve- or sham-surgery. Baseline burrowing behavior and evoked pain behaviors were assessed prior to model induction, and twice-weekly until study completion on day 14. For FCA- and CCI-rats, but not the corresponding groups of sham-rats, evoked mechanical hypersensitivity developed in a temporal manner in the ipsilateral hindpaws. Although burrowing behavior also decreased in a temporal manner for both FCA- and CCI-rats, there was considerable inter-animal variability. By contrast, mechanical hyperalgesia and mechanical allodynia in the ipsilateral hindpaws of FCA- and CCI-rats respectively, exhibited minimal inter-animal variability. Our data collectively show that burrowing behavior is altered in rodent models of chronic inflammatory pain and peripheral neuropathic pain. However, large group sizes are needed to ensure studies are adequately powered due to considerable inter-animal variability.

  17. Sensory Re-Weighting in Human Bipedal Postural Control: The Effects of Experimentally-Induced Plantar Pain.

    Directory of Open Access Journals (Sweden)

    Antoine Pradels

    Full Text Available The present study was designed to assess the effects of experimentally-induced plantar pain on the displacement of centre of foot pressure during unperturbed upright stance in different sensory conditions of availability and/or reliability of visual input and somatosensory input from the vestibular system and neck. To achieve this goal, fourteen young healthy adults were asked to stand as still as possible in three sensory conditions: (1 No-vision, (2 Vision, and (3 No-vision - Head tilted backward, during two experimental conditions: (1 a No-pain condition, and (2 a condition when a painful stimulation was applied to the plantar surfaces of both feet (Plantar-pain condition. Centre of foot pressure (CoP displacements were recorded using a force platform. Results showed that (1 experimentally-induced plantar pain increased CoP displacements in the absence of vision (No-vision condition, (2 this deleterious effect was more accentuated when somatosensory information from the vestibular and neck was altered (No-vision - Head tilted backward condition and (3 this deleterious effect was suppressed when visual information was available (Vision condition. From a fundamental point of view, these results lend support to the sensory re-weighting hypothesis whereby the central nervous system dynamically and selectively adjusts the relative contributions of sensory inputs (i.e. the sensory weightings in order to maintain balance when one or more sensory channels are altered by the task (novel or challenging, environmental or individual conditions. From a clinical point of view, the present findings further suggest that prevention and treatment of plantar pain may be relevant for the preservation or improvement of balance control, particularly in situations (or individuals in which information provided by the visual, neck proprioceptive and vestibular systems is unavailable or disrupted.

  18. Pain Management Practices by Nurses: An Application of the Knowledge, Attitude and Practices (KAP) Model.

    Science.gov (United States)

    Alzghoul, Bashar I; Abdullah, Nor Azimah Chew

    2015-10-26

    Pain is one of the most common reasons that drive people to go to hospitals. It has been found that several factors affect the practices of pain management. In this regard, this study aimed at investigating the underlying determinants in terms of pain management practices. Based on reviewing the previous studies and the suggestions of the KAP model, it was hypothesized that the main elements of the KAP model (attitudes and knowledge) significantly predict the variation in the practices of nurses regarding pain management. A questionnaire comprising the KAP model' s constructs, i.e. knowledge and attitude towards pain management, as well as pain management practices, was used to collect data from 266 registered nurses (n=266) who are deemed competent in the management of patients' pain in the Jordanian public hospitals. The two constructs, attitude and knowledge, which are the main determinants of the KAP model were found to independently predict nurses' practices of managing patients' pain. Knowledge of pain management was found to be the strongest predictor. Additionally, it was found that about 69% of the variance in pain management could be explained by the constructs of the KAP model. Therefore, it is recommended that the Jordanian hospitals and universities focus on nurses' knowledge and attitude towards pain management in order to enhance their practices in the field of pain management.

  19. Experimental models of autoimmune inflammatory ocular diseases

    Directory of Open Access Journals (Sweden)

    Fabio Gasparin

    2012-04-01

    Full Text Available Ocular inflammation is one of the leading causes of blindness and loss of vision. Human uveitis is a complex and heterogeneous group of diseases characterized by inflammation of intraocular tissues. The eye may be the only organ involved, or uveitis may be part of a systemic disease. A significant number of cases are of unknown etiology and are labeled idiopathic. Animal models have been developed to the study of the physiopathogenesis of autoimmune uveitis due to the difficulty in obtaining human eye inflamed tissues for experiments. Most of those models are induced by injection of specific photoreceptors proteins (e.g., S-antigen, interphotoreceptor retinoid-binding protein, rhodopsin, recoverin, phosducin. Non-retinal antigens, including melanin-associated proteins and myelin basic protein, are also good inducers of uveitis in animals. Understanding the basic mechanisms and pathogenesis of autoimmune ocular diseases are essential for the development of new treatment approaches and therapeutic agents. The present review describes the main experimental models of autoimmune ocular inflammatory diseases.

  20. The complexity model: a novel approach to improve chronic pain care.

    Science.gov (United States)

    Peppin, John F; Cheatle, Martin D; Kirsh, Kenneth L; McCarberg, Bill H

    2015-04-01

    More than 25% of the US population experiences chronic pain; yet few physicians specialize in the field of pain medicine. This article will review a theoretical model of care that stratifies treatment and patients by level and type of complexity and promotes communication between specialist and primary care providers. The undertreatment of pain was recently brought to national attention to encourage both clinicians and patients to advocate for improved pain care. The specialty of pain medicine and models of care, challenges of managing pain in a primary care setting, and the reliance on an opioid-focused approach are reviewed. An evolved model of pain care based on the complexity of pain and emphasizing a dynamic collaboration between the primary care provider and the pain specialist is discussed. From the perspective of the busy clinician, the treatment of chronic pain can be overwhelming. The scarcity of trained pain practitioners and the burgeoning number of patients with chronic pain necessitate a new approach that values the complex nature of chronic pain and offers a practical blueprint to meet these challenges. Wiley Periodicals, Inc.

  1. Promoting culturally competent chronic pain management using the clinically relevant continuum model.

    Science.gov (United States)

    Monsivais, Diane B

    2011-06-01

    This article reviews the culture of biomedicine and current practices in pain management education, which often merge to create a hostile environment for effective chronic pain care. Areas of cultural tensions in chronic pain frequently involve the struggle to achieve credibility regarding one's complaints of pain (or being believed that the pain is real) and complying with pain medication protocols. The clinically relevant continuum model is presented as a framework allowing providers to approach care from an evidence-based, culturally appropriate (patient centered) perspective that takes into account the highest level of evidence available, provider expertise, and patient preferences and values. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Experimental validation of model Hortel Whillier; Validacion experimental del model de Hottel-Whillier

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez Munoz, F.; Cejudo Lopez, J. M.; Carrillo andres, A.

    2010-07-01

    Comparing the results of testing of a commercial flat-plate solar collector with a detailed implementation model of Hottel Whillier fin and tube. The validation procedure is based on comparing experimental and theoretical curves and more likely uncertainty bands. the model correctly predicts the end of profits and underestimates the 5% of losses, although a sensitivity analysis shows that this result is not attributable to the model itself but to the inputs with which it was implemented. The model has difficulty differentiating between the terms of linear and quadratic losses that appear in the quadratic fit curve. (Author) 1 refs.

  3. Developing a model for measuring fear of pain in Norwegian samples: The Fear of Pain Questionnaire Norway.

    Science.gov (United States)

    Vambheim, Sara M; Lyby, Peter Solvoll; Aslaksen, Per M; Flaten, Magne Arve; Åsli, Ole; Bjørkedal, Espen; Martinussen, Laila M

    2017-11-09

    Fear of pain is highly correlated with pain report and physiological measures of arousal when pain is inflicted. The Fear of Pain Questionnaire III (FPQ-III) and The Fear of Pain Questionnaire Short Form (FPQ-SF) are self-report inventories developed for assessment of fear of pain (FOP). A previous study assessed the fit of the FPQ-III and the FPQ-SF in a Norwegian non-clinical sample and proved poor fit of both models. This inspired the idea of testing the possibility of a Norwegian FOP-model. A Norwegian FOP-model was examined by Exploratory Factor Analysis (EFA) in a sample of 1112 healthy volunteers. Then, the model fit of the FPQ-III, FPQ-SF and the Norwegian FOP-model (FPQ-NOR) were compared by Confirmatory Factor Analysis (CFA). Sex neutrality was explored by examining model fit, validity and reliability of the 3 models amongst male and female subgroups. The EFA suggested either a 4-, a 5- or a 6-factor Norwegian FOP model. The eigenvalue criterion supported the suggested 6-factor model, which also explained most of the variance and was most interpretable. A CFA confirmed that the 6-factor model was better than the two 4- and 5-factor models. Furthermore, the CFA used to test the fit of the FPQ-NOR, the FPQ-III and the FPQ-SF showed that the FPQ-NOR had the best fit of the 3 models, both in the whole sample and in sex sub-groups. A 6-factor model for explaining and measuring FOP in Norwegian samples was identified and termed the FPQ-NOR. This new model constituted six factors and 27 items, conceptualized as Minor, Severe, Injection, Fracture, Dental, and Cut Pain. The FPQ-NOR had the best fit overall and in male- and female subgroups, probably due to cross-cultural differences in FOP. This study highlights the importance on exploratory analysis of FOP-instruments when applied to different countries or cultures. As the FPQ-III is widely used in both research and clinical settings, it is important to ensure that the models construct validity is high. Country

  4. Therapeutic Effects of the Superoxide Dismutase Mimetic Compound Me2DO2A on Experimental Articular Pain in Rats

    Directory of Open Access Journals (Sweden)

    Lorenzo Di Cesare Mannelli

    2013-01-01

    Full Text Available Superoxide anion ( is overproduced in joint inflammation, rheumatoid arthritis, and osteoarthritis. Increased production leads to tissue damage, articular degeneration, and pain. In these conditions, the physiological defense against , superoxide dismutases (SOD are decreased. The complex MnL4 is a potent SOD mimetic, and in this study it was tested in inflammatory and osteoarticular rat pain models. In vivo protocols were approved by the animal Ethical Committee of the University of Florence. Pain was measured by paw pressure and hind limb weight bearing alterations tests. MnL4 (15 mg kg−1 acutely administered, significantly reduced pain induced by carrageenan, complete Freund’s adjuvant (CFA, and sodium monoiodoacetate (MIA. In CFA and MIA protocols, it ameliorated the alteration of postural equilibrium. When administered by osmotic pump in the MIA osteoarthritis, MnL4 reduced pain, articular derangement, plasma TNF alpha levels, and protein carbonylation. The scaffold ring was ineffective. MnL4 (10−7 M prevented the lipid peroxidation of isolated human chondrocytes when was produced by RAW 264.7. MnL4 behaves as a potent pain reliever in acute inflammatory and chronic articular pain, being its efficacy related to antioxidant property. Therefore MnL4 appears as a novel protective compound potentially suitable for the treatment of joint diseases.

  5. Comparison of Quadrapolar™ radiofrequency lesions produced by standard versus modified technique: an experimental model.

    Science.gov (United States)

    Safakish, Ramin

    2017-01-01

    Lower back pain (LBP) is a global public health issue and is associated with substantial financial costs and loss of quality of life. Over the years, different literature has provided different statistics regarding the causes of the back pain. The following statistic is the closest estimation regarding our patient population. The sacroiliac (SI) joint pain is responsible for LBP in 18%-30% of individuals with LBP. Quadrapolar™ radiofrequency ablation, which involves ablation of the nerves of the SI joint using heat, is a commonly used treatment for SI joint pain. However, the standard Quadrapolar radiofrequency procedure is not always effective at ablating all the sensory nerves that cause the pain in the SI joint. One of the major limitations of the standard Quadrapolar radiofrequency procedure is that it produces small lesions of ~4 mm in diameter. Smaller lesions increase the likelihood of failure to ablate all nociceptive input. In this study, we compare the standard Quadrapolar radiofrequency ablation technique to a modified Quadrapolar ablation technique that has produced improved patient outcomes in our clinic. The methodology of the two techniques are compared. In addition, we compare results from an experimental model comparing the lesion sizes produced by the two techniques. Taken together, the findings from this study suggest that the modified Quadrapolar technique provides longer lasting relief for the back pain that is caused by SI joint dysfunction. A randomized controlled clinical trial is the next step required to quantify the difference in symptom relief and quality of life produced by the two techniques.

  6. Effect of Experimental Hand Pain on Training-Induced Changes in Motor Performance and Corticospinal Excitability

    Directory of Open Access Journals (Sweden)

    Nicolas Mavromatis

    2017-02-01

    Full Text Available Pain influences plasticity within the sensorimotor system and the aim of this study was to assess the effect of pain on changes in motor performance and corticospinal excitability during training for a novel motor task. A total of 30 subjects were allocated to one of two groups (Pain, NoPain and performed ten training blocks of a visually-guided isometric pinch task. Each block consisted of 15 force sequences, and subjects modulated the force applied to a transducer in order to reach one of five target forces. Pain was induced by applying capsaicin cream to the thumb. Motor performance was assessed by a skill index that measured shifts in the speed–accuracy trade-off function. Neurophysiological measures were taken from the first dorsal interosseous using transcranial magnetic stimulation. Overall, the Pain group performed better throughout the training (p = 0.03, but both groups showed similar improvements across training blocks (p < 0.001, and there was no significant interaction. Corticospinal excitability in the NoPain group increased halfway through the training, but this was not observed in the Pain group (Time × Group interaction; p = 0.01. These results suggest that, even when pain does not negatively impact on the acquisition of a novel motor task, it can affect training-related changes in corticospinal excitability.

  7. Rostral Agranular Insular Cortex Lesion with Motor Cortex Stimulation Enhances Pain Modulation Effect on Neuropathic Pain Model

    Directory of Open Access Journals (Sweden)

    Hyun Ho Jung

    2016-01-01

    Full Text Available It is well known that the insular cortex is involved in the processing of painful input. The aim of this study was to evaluate the pain modulation role of the insular cortex during motor cortex stimulation (MCS. After inducing neuropathic pain (NP rat models by the spared nerve injury method, we made a lesion on the rostral agranular insular cortex (RAIC unilaterally and compared behaviorally determined pain threshold and latency in 2 groups: Group A (NP + MCS; n=7 and Group B (NP + RAIC lesion + MCS; n=7. Also, we simultaneously recorded neuronal activity (NP; n=9 in the thalamus of the ventral posterolateral nucleus and RAIC to evaluate electrophysiological changes from MCS. The pain threshold and tolerance latency increased in Group A with “MCS on” and in Group B with or without “MCS on.” Moreover, its increase in Group B with “MCS on” was more than that of Group B without MCS or of Group A, suggesting that MCS and RAIC lesioning are involved in pain modulation. Compared with the “MCS off” condition, the “MCS on” induced significant threshold changes in an electrophysiological study. Our data suggest that the RAIC has its own pain modulation effect, which is influenced by MCS.

  8. Tendon healing in vivo. An experimental model.

    Science.gov (United States)

    Abrahamsson, S O; Lundborg, G; Lohmander, L S

    1989-01-01

    Flexor tendon segments were incubated in a diffusion chamber in the subcutis of rabbits. Tendons incubated up to 6 weeks in the diffusion chamber showed proliferating and migrating cells from the epitenon cell layer as well as viable endotenon cells. Explants frozen in liquid nitrogen prior to incubation showed no signs of extrinsic cell contamination and remained non-viable indicating that no cell penetration occurred through the Millipore filter and that cell division seen in non-frozen and incubated tendons was an expression of intrinsic cellular proliferative capacity of the tendon. In tendon segments incubated in chambers for three weeks, collagen synthesis was reduced by 50% and the rate of cell proliferation measured as 3H-thymidine incorporation, was 15 times that of native tendons. Frozen and incubated tendons showed only traces of remaining matrix synthesis or cell proliferation. With this experimental model we have histologically and biochemically shown that tendons may survive and heal while the nutrition exclusively could be based on diffusion and the tendons have an intrinsic capacity of healing. The described model enables further studies on tendon healing and its regulation.

  9. Contribution of biopsychosocial risk factors to nonspecific neck pain in office workers: A path analysis model.

    Science.gov (United States)

    Paksaichol, Arpalak; Lawsirirat, Chaipat; Janwantanakul, Prawit

    2015-01-01

    The etiology of nonspecific neck pain is widely accepted to be multifactorial. Each risk factor has not only direct effects on neck pain but may also exert effects indirectly through other risk factors. This study aimed to test this hypothesized model in office workers. A one-year prospective cohort study of 559 healthy office workers was conducted. At baseline, a self-administered questionnaire and standardized physical examination were employed to gather biopsychosocial data. Follow-up data were collected every month for the incidence of neck pain. A regression model was built to analyze factors predicting the onset of neck pain. Path analysis was performed to examine direct and indirect associations between identified risk factors and neck pain. The onset of neck pain was predicted by female gender, having a history of neck pain, monitor position not being level with the eyes, and frequently perceived muscular tension, of which perceived muscular tension was the strongest effector on the onset of neck pain. Gender, history of neck pain, and monitor height had indirect effects on neck pain that were mediated through perceived muscular tension. History of neck pain was the most influential effector on perceived muscular tension. The results of this study support the hypothesis that each risk factors may contribute to the development of neck pain both directly and indirectly. The combination of risk factors necessary to cause neck pain is likely occupation specific. Perceived muscular tension is hypothesized to be an early sign of musculoskeletal symptoms.

  10. Experimental muscle pain during a forward lunge--the effects on knee joint dynamics and electromyographic activity

    DEFF Research Database (Denmark)

    Henriksen, Marius; Alkjaer, T; Simonsen, Erik Bruun

    2009-01-01

    . Isotonic saline (0.9%) was used as control. MAIN OUTCOME MEASUREMENTS: Three-dimensional movement analyses were performed and inverse dynamics were used to calculate joint kinematics and kinetics for ankle, knee and hip joints. Electromyographic (EMG) signals of the hamstrings and quadriceps muscles were......OBJECTIVE: The purpose of this study was to investigate whether the knee joint dynamics during a forward lunge could be modulated by experimentally induced vastus medialis pain in healthy subjects. DESIGN: Randomised cross-over study. SETTING: Biomechanical movement laboratory. PARTICIPANTS: 20...... recorded. RESULTS: During and after pain, significant decreases in knee joint dynamics and EMG recordings were observed. CONCLUSION: The study shows that local pain in the quadriceps is capable of modulating movements with high knee joint dynamics. The results may have implications in the management...

  11. Current Studies of Acupuncture in Cancer-Induced Bone Pain Animal Models

    OpenAIRE

    Ryu, Hee Kyoung; Baek, Yong-Hyeon; Park, Yeon-Cheol; Seo, Byung-Kwan

    2014-01-01

    Acupuncture is generally accepted as a safe and harmless treatment option for alleviating pain. To explore the pain mechanism, numerous animal models have been developed to simulate specific human pain conditions, including cancer-induced bone pain (CIBP). In this study, we analyzed the current research methodology of acupuncture for the treatment of CIBP. We electronically searched the PubMed database for animal studies published from 2000 onward using these search terms: (bone cancer OR can...

  12. Fluctuating experimental pain sensitivities across the menstrual cycle are contingent on women's romantic relationship status.

    Directory of Open Access Journals (Sweden)

    Jacob M Vigil

    Full Text Available We explored the social-signaling hypothesis that variability in exogenous pain sensitivities across the menstrual cycle is moderated by women's current romantic relationship status and hence the availability of a solicitous social partner for expressing pain behaviors in regular, isochronal ways. In two studies, we used the menstrual calendars of healthy women to provide a detailed approximation of the women's probability of conception based on their current cycle-day, along with relationship status, and cold pressor pain and ischemic pain sensitivities, respectively. In the first study (n = 135; 18-46 yrs., Mage = 23 yrs., 50% natural cycling, we found that naturally-cycling, pair-bonded women showed a positive correlation between the probability of conception and ischemic pain intensity (r = .45, associations not found for single women or hormonal contraceptive-users. A second study (n = 107; 19-29 yrs., Mage = 20 yrs., 56% natural cycling showed a similar association between greater conception risk and higher cold-pressor pain intensity in naturally-cycling, pair-bonded women only (r = .63. The findings show that variability in exogenous pain sensitivities across different fertility phases of the menstrual cycle is contingent on basic elements of women's social environment and inversely correspond to variability in naturally occurring, perimenstrual symptoms. These findings have wide-ranging implications for: a standardizing pain measurement protocols; b understanding basic biopsychosocial pain-related processes; c addressing clinical pain experiences in women; and d understanding how pain influences, and is influenced by, social relationships.

  13. Neural circuitry mediating inflammation-induced central pain amplification in human experimental endotoxemia.

    Science.gov (United States)

    Benson, Sven; Rebernik, Laura; Wegner, Alexander; Kleine-Borgmann, Julian; Engler, Harald; Schlamann, Marc; Forsting, Michael; Schedlowski, Manfred; Elsenbruch, Sigrid

    2015-08-01

    To elucidate the brain mechanisms underlying inflammation-induced visceral hyperalgesia in humans, in this functional magnetic resonance imaging (fMRI) study we tested if intravenous administration of lipopolysaccharide (LPS) involves altered central processing of visceral pain stimuli. In this randomized, double-blind, placebo-controlled fMRI study, 26 healthy male subjects received either an intravenous injection of low-dose LPS (N=14, 0.4 ng/kg body weight) or placebo (N=12, control group). Plasma cytokines (TNF-α, IL-6), body temperature, plasma cortisol and mood were assessed at baseline and up to 6 h post-injection. At baseline and 2 h post-injection (test), rectal pain thresholds and painful rectal distension-induced blood oxygen level-dependent (BOLD) responses in brain regions-of-interest were assessed. To address specificity for visceral pain, BOLD responses to non-painful rectal distensions and painful somatic stimuli (i.e., punctuate mechanical stimulation) were also analyzed as control stimuli. Compared to the control group, LPS-treated subjects demonstrated significant and transient increases in TNF-α, IL-6, body temperature and cortisol, along with impaired mood. In response to LPS, rectal pain thresholds decreased in trend, along with enhanced up-regulation of rectal pain-induced BOLD responses within the posterior insula, dorsolateral prefrontal (DLPFC), anterior midcingulate (aMCC) and somatosensory cortices (all FWE-corrected ppain-induced neural activation in DLPFC and aMCC. No significant LPS effects were observed on neural responses to non-painful rectal distensions or mechanical stimulation. These findings support that peripheral inflammatory processes affect visceral pain thresholds and the central processing of sensory-discriminative aspects of visceral pain. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. The role of executive functioning in children's attentional pain control: an experimental analysis.

    Science.gov (United States)

    Verhoeven, Katrien; Dick, Bruce; Eccleston, Christopher; Goubert, Liesbet; Crombez, Geert

    2014-02-01

    Directing attention away from pain is often used in children's pain treatment programs to control pain. However, empirical evidence concerning its effectiveness is inconclusive. We therefore sought to understand other influencing factors, including executive function and its role in the pain experience. This study investigates the role of executive functioning in the effectiveness of distraction. School children (n=164) completed executive functioning tasks (inhibition, switching, and working memory) and performed a cold-pressor task. One half of the children simultaneously performed a distracting tone-detection task; the other half did not. Results showed that participants in the distraction group were engaged in the distraction task and were reported to pay significantly less attention to pain than controls. Executive functioning influenced distraction task engagement. More specifically, participants with good inhibition and working memory abilities performed the distraction task better; participants with good switching abilities reported having paid more attention to the distraction task. Furthermore, distraction was found to be ineffective in reducing pain intensity and affect. Executive functioning did not influence the effectiveness of distraction. However, a relationship was found between executive functioning and pain affect, indicating that participants with good inhibition and working memory abilities experienced the cold-pressor task as less stressful and unpleasant. Our findings suggest that distraction as a process for managing pain is complex. While it appears that executive function may play a role in adult distraction, in this study it did not direct attention away from pain. It may instead be involved in the overall pain experience. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  15. Brief relaxation training is not sufficient to alter tolerance to experimental pain in novices.

    Science.gov (United States)

    Smith, Karen E; Norman, Greg J

    2017-01-01

    Relaxation techniques, such as deep breathing and muscle relaxation, are aspects common to most forms of mindfulness training. There is now an abundance of research demonstrating that mindfulness training has beneficial effects across a wide range of clinical conditions, making it an important tool for clinical intervention. One area of extensive research is on the beneficial effects of mindfulness on experiences of pain. However, the mechanisms of these effects are still not well understood. One hypothesis is that the relaxation components of mindfulness training, through alterations in breathing and muscle tension, leads to changes in parasympathetic and sympathetic nervous system functioning which influences pain circuits. The current study seeks to examine how two of the relaxation subcomponents of mindfulness training, deep breathing and muscle relaxation, influence experiences of pain in healthy individuals. Participants were randomized to either a 10 minute deep breathing, progressive muscle relaxation, or control condition after which they were exposed to a cold pain task. Throughout the experiment, measures of parasympathetic and sympathetic nervous system activity were collected to assess how deep breathing and progressive muscle relaxation alter physiological responses, and if these changes moderate any effects of these interventions on responses to pain. There were no differences in participants' pain tolerances or self-reported pain ratings during the cold pain task or in participants' physiological responses to the task. Additionally, individual differences in physiological functioning were not related to differences in pain tolerance or pain ratings. Overall this study suggests that the mechanisms through which mindfulness exerts its effects on pain are more complex than merely through physiological changes brought about by altering breathing or muscle tension. This indicates a need for more research examining the specific subcomponents of

  16. Experimental models for Murray’s law

    Science.gov (United States)

    Akita, Dai; Kunita, Itsuki; Fricker, Mark D.; Kuroda, Shigeru; Sato, Katsuhiko; Nakagaki, Toshiyuki

    2017-01-01

    Transport networks are ubiquitous in multicellular organisms and include leaf veins, fungal mycelia and blood vessels. While transport of materials and signals through the network plays a crucial role in maintaining the living system, the transport capacity of the network can best be understood in terms of hydrodynamics. We report here that plasmodium from the large, single-celled amoeboid Physarum was able to construct a hydrodynamically optimized vein-network when evacuating biomass from confined arenas of various shapes through a narrow exit. Increasingly thick veins developed towards the exit, and the network spanned the arena via repetitive bifurcations to give a branching tree. The Hausdorff distance from all parts of the plasmodium to the vein network was kept low, whilst the hydrodynamic conductivity from distal parts of the network to the exit was equivalent, irrespective of the arena shape. This combination of spatial patterning and differential vein thickening served to evacuate biomass at an equivalent rate across the entire arena. The scaling relationship at the vein branches was determined experimentally to be 2.53-3.29, consistent with predictions from Murray’s law. Furthermore, we show that mathematical models for self-organised, adaptive transport in Physarum simulate the experimental network organisation well if the scaling coefficient of the current-reinforcement rule is set to 3. In simulations, this resulted in rapid development of an optimal network that minimised the combined volume and frictional energy in comparison with other scaling coefficients. This would predict that the boundary shear forces within each vein are constant throughout the network, and would be consistent with a feedback mechanism based on a sensing a threshold shear at the vein wall.

  17. An experimental investigation of the effect of a justice violation on pain experience and expression among individuals with high and low just world beliefs.

    Science.gov (United States)

    Trost, Z; Scott, W; Lange, J M; Manganelli, L; Bernier, E; Sullivan, M J

    2014-03-01

    Perceptions of injustice are linked with poorer physical and psychological outcomes in the context of pain and injury. Violations of injustice can arise out of violations of just world belief (JWB). However, no study has yet examined whether JWB moderates the effect of justice violation on pain experience. The current study examined the effect of an experimental justice violation on acute pain outcomes and whether JWB moderated this effect. Participants completed the JWB scale and then engaged in two cold pressor tasks (CPT). Half the participants were told that the second CPT immersion was part of standard protocol; the other half were told that the painful procedure had to be repeated due to experimenter negligence. Participants provided report of pain intensity following each CPT immersion. Video records of participants undergoing the CPT were coded for presence and duration of pain behaviour. Exposure to the justice violation resulted in elevated pain intensity from the first to the second immersion only among participants with high JWB. For participants with low JWB and participants in the control condition, there was no significant difference in pain intensity across immersions. Control participants showed a decrease in pain behaviour from the first to the second immersion. In the negligence/ justice violation condition, reductions in pain behaviour were observed only among participants with low JWB. Our results indicate that individuals with high JWB may show particularly adverse reactions in response to justice violations in the context of acute pain experience. © 2013 European Pain Federation - EFIC®

  18. Evaluation of Analgesic Effects of Hydroalcoholic Extract of Allium cepa L. in Animal Model of Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Sanaz Mahdipour

    2017-05-01

    Full Text Available Abstract Background: Neuropathic pain is a chronic pain that affects on the patient’s quality of life. Use of herbal instead of synthetic drugs recently has been increased due to side effects of synthetic drugs and herbal effective components. Flavonoids are herbal compounds that have analgesic and anti-inflammatory effects. Because Allium cepa L. has a great amount of flavonoids, this study has been designed to evaluate analgesic effects of alcoholic extract of Allium cepa L. on neuropathic pain behavior in chronic constriction injury model in rats. Materials and Methods: In this experimental study, neuropathic pain induced by chronic constriction injury (CCI model in Rats. Animals were randomly divided into 4 groups (n=10 for each: Sham, CCI model, receiving red onion hydroalcoholic extract at a dose of 100 mg/kg and a group receiving gabapentin (100 mg/kg. Red onion extract and gabapentin were administered by gavage for 21 days. Using thermal hyperalgesia, mechanical and thermal allodynia tests, the analgesic effects of extract have been measured. Results: Findings of this study revealed that CCI surgery on rats induced hyperalgesia, mechanical and thermal allodynia. Daily intakes of alcoholic extract of red onion and gabapentin significantly increase the paw withdrawal latency; increase the threshold to mechanical allodynia and decrease in response to acetone. Conclusion: Oral use of alcoholic extract of Allium cepa L. reduces neuropathic pain behavior in CCI model in rats.

  19. A new tool for real-time pain assessment in experimental and clinical environments.

    Directory of Open Access Journals (Sweden)

    Nils Schaffner

    Full Text Available Pain measurement largely depends on the ability to rate personal subjective pain. Nevertheless, pain scales can be difficult to use during medical procedures. We hypothesized that pain can be expressed intuitively and in real-time by squeezing a pressure sensitive device. We developed such a device called "Painmouse(®" and tested it on healthy volunteers and patients in two separate studies: Sixteen male participants rated different painful heat stimuli via Painmouse(® and a Visual Analog Scale (VAS. Retest was done one week later. Participants clearly distinguished four distinct pain levels using both methods. Values from the first and second sessions were comparable. Thereafter, we tested the Painmouse(® by asking twelve female and male leg- ulcer patients to continuously squeeze it during the whole length of their wound-dressing change. Patients rated each step of dressing change on an 11-point numeric rating scale. Painmouse(® ratings were highest for the wound cleaning and debridement step. Application of the new dressing was not evaluated as very painful. On the other hand, numeric scale ratings did not differentiate between dressing change steps. We conclude that the Painmouse(® enables pain assessment even under difficult clinical circumstances, such as during a medical treatment in elderly patients.

  20. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    Functional abdominal pain--that is, pain without demonstrable organic abnormalities--has often been associated with psychologic stress. The aim of the present study was to investigate whether sympathetic nervous system response to laboratory stress and basal parasympathetic neural activity were...

  1. Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Graven-Nielsen, Thomas; Aaboe, Jens

    2010-01-01

    Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease progress...

  2. Experimental pain processing in individuals with cognitive impairment: current state of the science

    DEFF Research Database (Denmark)

    Defrin, R; Amanzio, Martina; de Tomasso, M

    2015-01-01

    clinical condition) and may also depend on the type of pain stimulation used and the type of pain responses assessed. Nevertheless, it is clear that regardless of the etiology of CI, patients do feel noxious stimuli; with more evidence for hypersensitivity than hyposensitivity to these stimuli compared...

  3. A biopsychosocial-spiritual model of chronic pain in adults with sickle cell disease.

    Science.gov (United States)

    Taylor, Lou Ella V; Stotts, Nancy A; Humphreys, Janice; Treadwell, Marsha J; Miaskowski, Christine

    2013-12-01

    Chronic pain in adults with sickle cell disease (SCD) is a complex multidimensional experience that includes biologic, psychologic, sociologic, and spiritual factors. To date, three models of pain associated with SCD (i.e., biomedical model, biopsychosocial model for SCD pain, and Health Beliefs Model) have been published. The biopsychosocial multidimensional approach to chronic pain developed by Turk and Gatchel is a widely used model of chronic pain. However, this model has not been applied to chronic pain associated with SCD. In addition, a spiritual/religious dimension is not included in this model. Because spirituality/religion is central to persons affected by SCD, that dimension needs to be added to any model of chronic pain in adults with SCD. In fact, data from one study suggest that spirituality/religiosity is associated with decreased pain intensity in adults with chronic pain from SCD. A biopsychosocial-spiritual model is proposed for adults with chronic pain from SCD, because it embraces the whole person. This model includes the biologic, psychologic, sociologic, and spiritual factors relevant to adults with SCD based on past and current research. The purpose of this paper is to describe an adaptation of Turk and Gatchel's model of chronic pain for adults with SCD and to summarize research findings that support each component of the revised model (i.e., biologic, psychologic, sociologic, spiritual). The paper concludes with a discussion of implications for the use of this model in research. Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  4. An animal model of pain produced by systemic administration of an immunotherapeutic anti-ganglioside antibody

    NARCIS (Netherlands)

    Slart, R.; Yu, A L; Yaksh, T L; Sorkin, L S

    For the management of pediatric neuroblastoma, a promising experimental treatment includes slow systemic infusion of a human/mouse chimeric monoclonal antibody against the GD2 ganglioside. Beneficial actions are however, accompanied by severe pain and altered cardiovascular tone. The pain is

  5. Efficacy of Intrathecal Morphine in a Model of Surgical Pain in Rats.

    Directory of Open Access Journals (Sweden)

    Aurelie Thomas

    Full Text Available Concerns over interactions between analgesics and experimental outcomes are a major reason for withholding opioids from rats undergoing surgical procedures. Only a fraction of morphine injected intravenously reaches receptors responsible for analgesia in the central nervous system. Intrathecal administration of morphine may represent a way to provide rats with analgesia while minimizing the amount of morphine injected. This study aimed to assess whether morphine injected intrathecally via direct lumbar puncture provides sufficient analgesia to rats exposed to acute surgical pain (caudal laparotomy.In an initial blinded, randomised study, pain-free rats received morphine subcutaneously (MSC, 3mg.kg-1, N = 6, intrathecally (MIT, 0.2mg.kg-1, N = 6; NaCl subcutaneously (NSC, N = 6 or intrathecally (NIT, N = 6. Previously validated pain behaviours, activity and Rat Grimace Scale (RGS scores were recorded at baseline, 1, 2, 4 and 8h post-injection. Morphine-treated rats had similar behaviours to NaCl rats, but their RGS scores were significantly different over time and between treatments. In a second blinded study, rats (N = 28 were randomly allocated to one of the following four treatments (N = 7: MSC, 3mg.kg-1, surgery; MIT, 0.2mg.kg-1, surgery; NIT, surgery; NSC, sham surgery. Composite Pain Behaviours (CPB and RGS were recorded as previously. CPB in MIT and MSC groups were not significantly different to NSC group. MSC and MIT rats displayed significantly lower RGS scores than NIT rats at 1 and 8h postoperatively. RGS scores for MIT and MSC rats were not significantly different at 1, 2, and 8h postoperatively. Intraclass correlation value amongst operators involved in RGS scoring (N = 9 was 0.913 for total RGS score. Intrathecal morphine was mostly indistinguishable from its subcutaneous counterpart, providing pain relief lasting up to 8 hours in a rat model of surgical pain. Further studies are warranted to clarify the relevance of the rat grimace

  6. Extreme Pain From Brown Recluse Spider Bites Model for Cytokine-Driven Pain

    Science.gov (United States)

    Payne, Katie S.; Schilli, Karen; Meier, Katlyn; Rader, Ryan K.; Dyer, Jonathan A.; Mold, James W.; Green, Jonathan A.; Stoecker, William V.

    2014-01-01

    Importance Bites from the brown recluse spider (BRS) can cause extreme pain. We propose cytokine release as a cause of the discomfort and a central mechanism through glial cell upregulation to explain measured pain levels and time course. Observations Twenty-three BRS bites were scored at a probable or documented level clinically, and an enzyme-linked immunosorbent assay was used to confirm the presence of BRS venom. The mean (SD) pain level in these cases 24 hours after the spider bite was severe: 6.74 (2.75) on a scale of 0 to 10. Narcotics may be needed to provide relief in some cases. The difference in pain level by anatomic region was not significant. Escalation observed in 22 of 23 cases, increasing from low/none to extreme within 24 hours, is consistent with a cytokine pain pattern, in which pain increases concomitantly with a temporal increase of inflammatory cytokines. Conclusions and Relevance These findings in BRS bites support the hypothesis of cytokine release in inflammatory pain. A larger series is needed to confirm the findings reported here. The extreme pain from many BRS bites motivates us to find better prevention and treatment techniques. PMID:25076008

  7. Extreme pain from brown recluse spider bites: model for cytokine-driven pain.

    Science.gov (United States)

    Payne, Katie S; Schilli, Karen; Meier, Katlyn; Rader, Ryan K; Dyer, Jonathan A; Mold, James W; Green, Jonathan A; Stoecker, William V

    2014-11-01

    Bites from the brown recluse spider (BRS) can cause extreme pain. We propose cytokine release as a cause of the discomfort and a central mechanism through glial cell upregulation to explain measured pain levels and time course. Twenty-three BRS bites were scored at a probable or documented level clinically, and an enzyme-linked immunosorbent assay was used to confirm the presence of BRS venom. The mean (SD) pain level in these cases 24 hours after the spider bite was severe: 6.74 (2.75) on a scale of 0 to 10. Narcotics may be needed to provide relief in some cases. The difference in pain level by anatomic region was not significant. Escalation observed in 22 of 23 cases, increasing from low/none to extreme within 24 hours, is consistent with a cytokine pain pattern, in which pain increases concomitantly with a temporal increase of inflammatory cytokines. These findings in BRS bites support the hypothesis of cytokine release in inflammatory pain. A larger series is needed to confirm the findings reported here. The extreme pain from many BRS bites motivates us to find better prevention and treatment techniques.

  8. Testing a model of pain appraisal and coping in children with chronic abdominal pain.

    Science.gov (United States)

    Walker, Lynn S; Smith, Craig A; Garber, Judy; Claar, Robyn Lewis

    2005-07-01

    This prospective study of children with recurrent abdominal pain (N=133; ages 8--15 years) used path analysis to examine relations among dispositional pain beliefs and coping styles, cognitions and behavior related to a specific pain episode, and short- and long-term outcomes. Children believing they could not reduce or accept pain appraised their episode-specific coping ability as low and reported passive coping behavior. Dispositional passive coping had direct effects on both episode-specific passive coping and long-term symptoms and disability. Accommodative coping (acceptance and self-encouragement) was associated with reduced episode-specific distress, which itself predicted reduced depressive symptoms 3 months later. Results suggest that coping-skill interventions for children with chronic pain should target reductions in passive coping and consider the potential benefits of accommodative coping strategies.

  9. A review of the evidence linking adult attachment theory and chronic pain: presenting a conceptual model.

    Science.gov (United States)

    Meredith, Pamela; Ownsworth, Tamara; Strong, Jenny

    2008-03-01

    It is now well established that pain is a multidimensional phenomenon, affected by a gamut of psychosocial and biological variables. According to diathesis-stress models of chronic pain, some individuals are more vulnerable to developing disability following acute pain because they possess particular psychosocial vulnerabilities which interact with physical pathology to impact negatively upon outcome. Attachment theory, a theory of social and personality development, has been proposed as a comprehensive developmental model of pain, implicating individual adult attachment pattern in the ontogenesis and maintenance of chronic pain. The present paper reviews and critically appraises studies which link adult attachment theory with chronic pain. Together, these papers offer support for the role of insecure attachment as a diathesis (or vulnerability) for problematic adjustment to pain. The Attachment-Diathesis Model of Chronic Pain developed from this body of literature, combines adult attachment theory with the diathesis-stress approach to chronic pain. The evidence presented in this review, and the associated model, advances our understanding of the developmental origins of chronic pain conditions, with potential application in guiding early pain intervention and prevention efforts, as well as tailoring interventions to suit specific patient needs.

  10. Cannabinoids attenuate cancer pain and proliferation in a mouse model.

    Science.gov (United States)

    Saghafi, Negin; Lam, David K; Schmidt, Brian L

    2011-01-25

    We investigated the effects of cannabinoid receptor agonists on (1) oral cancer cell viability in vitro and (2) oral cancer pain and tumor growth in a mouse cancer model. We utilized immunohistochemistry and Western blot to show that human oral cancer cells express CBr1 and CBr2. When treated with WIN55,212-2 (non-selective), ACEA (CBr1-selective) or AM1241 (CBr2-selective) agonists in vitro, oral cancer cell proliferation was significantly attenuated in a dose-dependent manner. In vivo, systemic administration (0.013M) of WIN55,212-2, ACEA, or AM1241 significantly attenuated cancer-induced mechanical allodynia. Tumor growth was also significantly attenuated with systemic AM1241 administration. Our findings suggest a direct role for cannabinoid mechanisms in oral cancer pain and proliferation. The systemic administration of cannabinoid receptor agonists may have important therapeutic implications wherein cannabinoid receptor agonists may reduce morbidity and mortality of oral cancer. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Hyperalgesia in a human model of acute inflammatory pain: a methodological study

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    was demonstrated by significantly higher pain thresholds and lower pain responses on the second and third day of the study. The burn model is a sensitive psychophysical model of acute inflammatory pain, when cross-over designs and within-day comparisons are used, and the model is suitable for double-blind, placebo......The aim of the study was to examine reproducibility of primary and secondary hyperalgesia in a psychophysical model of human inflammatory pain. Mild burns were produced on the crura of 12 volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min). Assessments of (i) cold and warm detection...

  12. Can multivariate models based on MOAKS predict OA knee pain? Data from the Osteoarthritis Initiative

    Science.gov (United States)

    Luna-Gómez, Carlos D.; Zanella-Calzada, Laura A.; Galván-Tejada, Jorge I.; Galván-Tejada, Carlos E.; Celaya-Padilla, José M.

    2017-03-01

    Osteoarthritis is the most common rheumatic disease in the world. Knee pain is the most disabling symptom in the disease, the prediction of pain is one of the targets in preventive medicine, this can be applied to new therapies or treatments. Using the magnetic resonance imaging and the grading scales, a multivariate model based on genetic algorithms is presented. Using a predictive model can be useful to associate minor structure changes in the joint with the future knee pain. Results suggest that multivariate models can be predictive with future knee chronic pain. All models; T0, T1 and T2, were statistically significant, all p values were 0.60.

  13. Experimental Muscle Pain Impairs the Synergistic Modular Control of Neck Muscles.

    Science.gov (United States)

    Gizzi, Leonardo; Muceli, Silvia; Petzke, Frank; Falla, Deborah

    2015-01-01

    A motor task can be performed via different patterns of muscle activation that show regularities that can be factorized in combinations of a reduced number of muscle groupings (also referred to as motor modules, or muscle synergies). In this study we evaluate whether an acute noxious stimulus induces a change in the way motor modules are combined to generate movement by neck muscles. The neck region was selected as it is a region with potentially high muscular redundancy. We used the motor modules framework to assess the redistribution of muscular activity of 12 muscles (6 per side) in the neck region of 8 healthy individuals engaged in a head and neck aiming task, in non-painful conditions (baseline, isotonic saline injection, post pain) and after the injection of hypertonic saline into the right splenius capitis muscle. The kinematics of the task was similar in the painful and control conditions. A general decrease of activity was noted for the injected muscle during the painful condition together with an increase or decrease of the activity of the other muscles. Subjects did not adopt shared control strategies (motor modules inter subject similarity at baseline 0.73±0.14); the motor modules recorded during the painful condition could not be used to reconstruct the activation patterns of the control conditions, and the painful stimulus triggered a subject-specific redistribution of muscular activation (i.e., in some subjects the activity of a given muscle increased, whereas in other subjects it decreased with pain). Alterations of afferent input (i.e., painful stimulus) influenced motor control at a multi muscular level, but not kinematic output. These findings provide new insights into the motor adaptation to pain.

  14. Expanding the social communication model of pain: are adult attachment characteristics associated with observers' pain-related evaluations?

    Science.gov (United States)

    Bailey, S Jeffrey; McWilliams, Lachlan A; Dick, Bruce D

    2012-02-01

    Evaluations of another's pain can have important implications in medical, employment, and social settings. Influenced by the Social Communication Model of Pain, this vignette-based study investigated the potential influence of characteristics of the person being evaluated (viz., the coping strategy used by an individual with chronic pain depicted in a vignette) and characteristics of those making evaluations (viz., self-reported attachment anxiety and avoidance of the study participants). The main hypothesis was that participants higher in attachment avoidance would be more critical in their evaluations than those lower in attachment avoidance. Undergraduate students (N = 267) read 1 of 2 vignettes about an individual experiencing chronic pain, provided ratings of this individual, and completed a measure of adult attachment. The vignettes varied in terms of the pain-related coping strategy (catastrophizing vs. distraction) described. Similar to past research, the catastrophizing vignette received more negative ratings than the distraction vignette (e.g., greater disability level), and female participants provided more positive ratings than male participants (e.g., greater deservingness of support). While the attachment variables were unrelated to some dependent variables, consistent with the main hypothesis, attachment avoidance was associated with lower ratings of perceived deservingness of support and desirability as a friend. The current findings suggest that chronic pain patients' coping styles influence evaluations made about them, and that evaluators' gender and attachment characteristics also have important effects on such evaluations.

  15. Stress-induced visceral pain: toward animal models of irritable-bowel syndrome and associated comorbidities.

    Science.gov (United States)

    Moloney, Rachel D; O'Mahony, Siobhain M; Dinan, Timothy G; Cryan, John F

    2015-01-01

    Visceral pain is a global term used to describe pain originating from the internal organs, which is distinct from somatic pain. It is a hallmark of functional gastrointestinal disorders such as irritable-bowel syndrome (IBS). Currently, the treatment strategies targeting visceral pain are unsatisfactory, with development of novel therapeutics hindered by a lack of detailed knowledge of the underlying mechanisms. Stress has long been implicated in the pathophysiology of visceral pain in both preclinical and clinical studies. Here, we discuss the complex etiology of visceral pain reviewing our current understanding in the context of the role of stress, gender, gut microbiota alterations, and immune functioning. Furthermore, we review the role of glutamate, GABA, and epigenetic mechanisms as possible therapeutic strategies for the treatment of visceral pain for which there is an unmet medical need. Moreover, we discuss the most widely described rodent models used to model visceral pain in the preclinical setting. The theory behind, and application of, animal models is key for both the understanding of underlying mechanisms and design of future therapeutic interventions. Taken together, it is apparent that stress-induced visceral pain and its psychiatric comorbidities, as typified by IBS, has a multifaceted etiology. Moreover, treatment strategies still lag far behind when compared to other pain modalities. The development of novel, effective, and specific therapeutics for the treatment of visceral pain has never been more pertinent.

  16. The effect of spinal manipulation on deep experimental muscle pain in healthy volunteers

    DEFF Research Database (Denmark)

    O'Neill, Søren; Ødegaard-Olsen, Øystein; Søvde, Beate

    2015-01-01

    BACKGROUND: High-velocity low-amplitude (HVLA) spinal manipulation is commonly used in the treatment of spinal pain syndromes. The mechanisms by which HVLA-manipulation might reduce spinal pain are not well understood, but often assumed to relate to the reduction of biomechanical dysfunction....... It is also possible however, that HVLA-manipulation involves a segmental or generalized inhibitory effect on nociception, irrespective of biomechanical function. In the current study it was investigated whether a local analgesic effect of HVLA-manipulation on deep muscle pain could be detected, in healthy...... individuals. METHODS AND MATERIALS: Local, para-spinal muscle pain was induced by injection of 0.5 ml sterile, hyper-tonic saline on two separate occasions 1 week apart. Immediately following the injection, treatment was administered as either a) HVLA-manipulation or b) placebo treatment, in a randomized...

  17. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    as the mean square successive differences of the R-R intervals (MSSD), indicating a higher basal parasympathetic neural activity (mean MSSD +/- SEM = 64 +/- 6 msec in the functional group, 46 +/- 6 msec in the healthy group, and 49 +/- 6 msec in the organic group; P = 0.03). A reduced sympathetic neural......Functional abdominal pain--that is, pain without demonstrable organic abnormalities--has often been associated with psychologic stress. The aim of the present study was to investigate whether sympathetic nervous system response to laboratory stress and basal parasympathetic neural activity were...... disturbed in 22 patients with functional abdominal pain (functional group) as compared with 14 healthy controls (healthy group) and 26 patients with organic abdominal pain (organic group) due to duodenal ulcer (DU), gallstones, or urinary tract calculi. Plasma adrenocorticotrophic hormone (ACTH) and serum...

  18. Changes in pain catastrophizing predict later changes in fibromyalgia clinical and experimental pain report: cross-lagged panel analyses of dispositional and situational catastrophizing

    National Research Council Canada - National Science Library

    Campbell, Claudia M; McCauley, Lea; Bounds, Sara C; Mathur, Vani A; Conn, Lora; Simango, Mpepera; Edwards, Robert R; Fontaine, Kevin R

    2012-01-01

    Fibromyalgia (FM), characterized by wide-spread diffuse pain and sensory abnormalities, is associated with elevated indices of distress and pain-related catastrophizing compared to both pain-free samples and those...

  19. Injury Based on Its Study in Experimental Models

    Directory of Open Access Journals (Sweden)

    M. Mendes-Braz

    2012-01-01

    Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

  20. Biomass thermochemical gasification: Experimental studies and modeling

    Science.gov (United States)

    Kumar, Ajay

    The overall goals of this research were to study the biomass thermochemical gasification using experimental and modeling techniques, and to evaluate the cost of industrial gas production and combined heat and power generation. This dissertation includes an extensive review of progresses in biomass thermochemical gasification. Product gases from biomass gasification can be converted to biopower, biofuels and chemicals. However, for its viable commercial applications, the study summarizes the technical challenges in the gasification and downstream processing of product gas. Corn stover and dried distillers grains with solubles (DDGS), a non-fermentable byproduct of ethanol production, were used as the biomass feedstocks. One of the objectives was to determine selected physical and chemical properties of corn stover related to thermochemical conversion. The parameters of the reaction kinetics for weight loss were obtained. The next objective was to investigate the effects of temperature, steam to biomass ratio and equivalence ratio on gas composition and efficiencies. DDGS gasification was performed on a lab-scale fluidized-bed gasifier with steam and air as fluidizing and oxidizing agents. Increasing the temperature resulted in increases in hydrogen and methane contents and efficiencies. A model was developed to simulate the performance of a lab-scale gasifier using Aspen Plus(TM) software. Mass balance, energy balance and minimization of Gibbs free energy were applied for the gasification to determine the product gas composition. The final objective was to optimize the process by maximizing the net energy efficiency, and to estimate the cost of industrial gas, and combined heat and power (CHP) at a biomass feedrate of 2000 kg/h. The selling price of gas was estimated to be 11.49/GJ for corn stover, and 13.08/GJ for DDGS. For CHP generation, the electrical and net efficiencies were 37 and 86%, respectively for corn stover, and 34 and 78%, respectively for DDGS. For

  1. Re-thinking pain educational strategies: Pain a new model using e-learning and PBL.

    Science.gov (United States)

    Keyte, Donna; Richardson, Cliff

    2011-02-01

    Despite some high profile reorganisation including the introduction of acute pain teams, many patients still experience unnecessary pain. Traditional teaching and learning strategies seem to have made little impact in clinical practice. This paper explores the possible reasons for this and identifies the need to help postregistration students transfer (re-contextualise) what they are learning to practice. A new, more flexible pain management module utilising a blended face to face/e-learning approach within a problem-based learning philosophy was introduced to increase knowledge in pain management whilst also attempting to overcome the barriers to knowledge transfer into practice. This is done by challenging attitudes and encouraging students to explore their clinical practice alongside theoretical concepts. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Involvement of NGF in the Rat Model of Persistent Muscle Pain Associated With Taut Band

    OpenAIRE

    Li, Jun; Yi, Shuang-Qin; Wang, Heng-Xiao; Yi, Nozomi; Ogawa, Yuki; OZAKI, NORIYUKI; Itoh, Masahiro

    2011-01-01

    Myofascial pain syndrome (MPS) is an important clinical condition characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). However, its pathogenic mechanism is still unclear. We developed an animal model relevant to conditions of MPS, and analyzed the mechanism of the muscle pain in this model. We applied eccentric contraction (EC) to a rat's gastrocnemius muscle (GM) for 2 weeks, and examined the mechanical withdrawal thresholds, histological ch...

  3. Hypnosis and Local Anesthesia for Dental Pain Relief-Alternative or Adjunct Therapy?-A Randomized, Clinical-Experimental Crossover Study.

    Science.gov (United States)

    Wolf, Thomas Gerhard; Wolf, Dominik; Callaway, Angelika; Below, Dagna; d'Hoedt, Bernd; Willershausen, Brita; Daubländer, Monika

    2016-01-01

    This prospective randomized clinical crossover trial was designed to compare hypnosis and local anesthesia for experimental dental pain relief. Pain thresholds of the dental pulp were determined. A targeted standardized pain stimulus was applied and rated on the Visual Analogue Scale (0-10). The pain threshold was lower under hypnosis (58.3 ± 17.3, p local anesthesia. The pain stimulus was scored higher under hypnosis (3.9 ± 3.8) than with local anesthesia (0.0, p Local anesthesia was superior to hypnosis and is a safe and effective method for pain relief in dentistry. Hypnosis seems to produce similar effects observed under sedation. It can be used in addition to local anesthesia and in individual cases as an alternative for pain control in dentistry.

  4. PMWS: Experimental model and co-infections

    DEFF Research Database (Denmark)

    Allan, G. M.; McNeilly, F.; Ellis, J

    2004-01-01

    and pneumonia and typical histological lesions include lymphocytic depletion and multinucleated giant cell formation in lymph nodes, degeneration and necrosis of hepatocytes, and multifocal lymphohistocytic interstitial pneumonia. This communication will review the results of experimental infections...

  5. Nerve growth factor blockade for the management of osteoarthritis pain: what can we learn from clinical trials and preclinical models?

    Science.gov (United States)

    Miller, Rachel E; Block, Joel A; Malfait, Anne-Marie

    2017-01-01

    Anti-nerve growth factor (NGF) antibodies hold tremendous potential for the management of osteoarthritis pain, but clinical trials have revealed serious adverse effects that are incompletely understood. This review discusses clinical trial results along with preclinical studies that have assessed NGF blockade in experimental osteoarthritis, in order to provide insight for future studies. Systematic reviews have revealed that anti-NGF therapy, including tanezumab, is efficacious in improving pain and function, but serious adverse events, including rapidly progressive osteoarthritis and osteonecrosis, resulted in a moratorium on trials that was only recently lifted. Within the past year, preclinical testing has revealed effects of NGF blockade on both pain behaviors and joint structure in experimental models of osteoarthritis. Similar to clinical trial results, these studies in laboratory animals demonstrated analgesic efficacy of NGF blockade. Interestingly, several animal studies have suggested detrimental effects on joint integrity as a result of treatment, particularly when treatment is started early in the disease, when joint damage is mild to moderate. NGF blockade continues to represent a promising new approach for the treatment of osteoarthritis pain, but the actual benefits and risks remain to be fully elucidated. Preclinical models may suggest patient populations that could be best served while limiting side-effects, but future work should further investigate the mechanisms of benefits and unwanted side-effects.

  6. Animal models of pain and migraine in drug discovery

    DEFF Research Database (Denmark)

    Munro, Gordon; Jansen-Olesen, Inger; Olesen, Jes

    2017-01-01

    Preclinical research activities in relation to pain typically involve the 'holy trinity' of nociceptive, inflammatory and neuropathic pain for purposes of target validation and defining target product profiles of novel analgesic compounds. For some reason it seems that headache or migraine...... are rarely considered as additional entities to explore. Frontline medications used in the treatment of, for example, inflammatory pain, neuropathic pain and migraine (NSAIDs versus pregabalin/duloxetine versus triptans) reveal distinct differences in pathophysiology that partially explain this approach....... Nevertheless, for many patients enduring chronic pain, regardless of aetiology, high unmet needs remain. By focusing more on commonalities shared between neuropathic pain and headache disorders such as migraine, drug discovery efforts could be spread more efficiently across a larger indication area. Here, some...

  7. A Model-Based Approach for Joint Analysis of Pain Intensity and Opioid Consumption in Postoperative Pain

    DEFF Research Database (Denmark)

    Juul, Rasmus V; Knøsgaard, Katrine R; Olesen, Anne E

    2016-01-01

    intensity and opioid consumption in a 4-h postoperative period for 44 patients undergoing percutaneous kidney stone surgery. Analysis was based on 748 Numerical Rating Scale (NRS) scores of pain intensity and 51 observed morphine and oxycodone dosing events. A joint model was developed to describe...

  8. Spinal nociceptive reflexes are sensitized in the monosodium iodoacetate model of osteoarthritis pain in the rat.

    Science.gov (United States)

    Kelly, S; Dobson, K L; Harris, J

    2013-09-01

    Evidence suggests that osteoarthritis (OA) is associated with altered central pain processing. We assessed the effects of experimentally induced OA on the excitability of spinal nociceptive withdrawal reflexes (NWRs), and their supraspinal control in a preclinical OA model. Experimental OA was induced in rats with knee injection of monosodium iodoacetate (MIA) and pain behaviour was assessed. 14/28 days post-MIA or saline injection, rats were anaesthetised for spinal NWR recording from tibialis anterior (TA) and biceps femoris (BF) hind limb muscles during plantar hind paw stimulation. Thresholds, receptive field sizes and wind up (incremental increase to repetitive stimulation) were measured in intact (d14/28) and spinalised (severed spinal cord; d28) MIA- and saline-injected rats. MIA reduced BF mechanical thresholds at day 28. Spinalisation of MIA rats did not prevent this hyperexcitability, and failed to produce the reduction in reflex receptive field (RRF) size observed in saline rats. These data indicate that MIA induces a hyperexcitability of BF NWR circuits that is maintained at the spinal level. In contrast, MIA appeared to have no effect on NWRs evoked by mechanical stimuli in the ankle flexor TA in intact rats, however spinalisation revealed hyperexcitability. Thus, 28 days following MIA-treatment, descending supraspinal inhibition normalised TA NWRs and was only overcome following repetitive noxious stimulation during wind up. We demonstrate that spinal nociceptive reflex pathways are sensitized following the development of OA, suggesting the presence of central sensitization. Further, our data reflect OA-induced alterations in the descending control of reflex responses. Our findings contribute to a mechanism-based understanding of OA pain. © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  9. Animal models of pancreatitis: Can it be translated to human pain study?

    Science.gov (United States)

    Zhao, Jing-Bo; Liao, Dong-Hua; Nissen, Thomas Dahl

    2013-01-01

    Chronic pancreatitis affects many individuals around the world, and the study of the underlying mechanisms leading to better treatment possibilities are important tasks. Therefore, animal models are needed to illustrate the basic study of pancreatitis. Recently, animal models of acute and chronic pancreatitis have been thoroughly reviewed, but few reviews address the important aspect on the translation of animal studies to human studies. It is well known that pancreatitis is associated with epigastric pain, but the understanding regarding to mechanisms and appropriate treatment of this pain is still unclear. Using animal models to study pancreatitis associated visceral pain is difficult, however, these types of models are a unique way to reveal the mechanisms behind pancreatitis associated visceral pain. In this review, the animal models of acute, chronic and un-common pancreatitis are briefly outlined and animal models related to pancreatitis associated visceral pain are also addressed. PMID:24259952

  10. The antinociceptive effect and adverse drug reactions of oxycodone in human experimental pain in relation to genetic variations in the OPRM1 and ABCB1 genes

    DEFF Research Database (Denmark)

    Zwisler, Stine T; Enggaard, Thomas P; Noehr-Jensen, Lene

    2010-01-01

    subjects exposed to experimental pain including electrical stimulation and the cold pressor test were included. A118G: We found that the variant G allele was associated with reduced antinociceptive effect as measured by pain tolerance thresholds to single electrical nerve stimulation (8% increase vs. 25...

  11. Modeling and analysis of the molecular basis of pain in sensory neurons.

    Directory of Open Access Journals (Sweden)

    Sang Ok Song

    Full Text Available Intracellular calcium dynamics are critical to cellular functions like pain transmission. Extracellular ATP plays an important role in modulating intracellular calcium levels by interacting with the P2 family of surface receptors. In this study, we developed a mechanistic mathematical model of ATP-induced P2 mediated calcium signaling in archetype sensory neurons. The model architecture, which described 90 species connected by 162 interactions, was formulated by aggregating disparate molecular modules from literature. Unlike previous models, only mass action kinetics were used to describe the rate of molecular interactions. Thus, the majority of the 252 unknown model parameters were either association, dissociation or catalytic rate constants. Model parameters were estimated from nine independent data sets taken from multiple laboratories. The training data consisted of both dynamic and steady-state measurements. However, because of the complexity of the calcium network, we were unable to estimate unique model parameters. Instead, we estimated a family or ensemble of probable parameter sets using a multi-objective thermal ensemble method. Each member of the ensemble met an error criterion and was located along or near the optimal trade-off surface between the individual training data sets. The model quantitatively reproduced experimental measurements from dorsal root ganglion neurons as a function of extracellular ATP forcing. Hypothesized architecture linking phosphoinositide regulation with P2X receptor activity explained the inhibition of P2X-mediated current flow by activated metabotropic P2Y receptors. Sensitivity analysis using individual and the whole system outputs suggested which molecular subsystems were most important following P2 activation. Taken together, modeling and analysis of ATP-induced P2 mediated calcium signaling generated qualitative insight into the critical interactions controlling ATP induced calcium dynamics

  12. Pain in patients with multiple sclerosis: a complex assessment including quantitative and qualitative measurements provides for a disease-related biopsychosocial pain model

    Directory of Open Access Journals (Sweden)

    Michalski D

    2011-08-01

    Full Text Available Dominik Michalski1,*, Stefanie Liebig1,*, Eva Thomae1,2, Andreas Hinz3, Florian Then Bergh1,21Department of Neurology, 2Translational Centre for Regenerative Medicine (TRM, 3Department of Medical Psychology and Medical Sociology, University of Leipzig, Leipzig, Germany *These authors contributed equallyBackground: Pain of various causes is a common phenomenon in patients with Multiple Sclerosis (MS. A biopsychosocial perspective has proven a useful theoretical construct in other chronic pain conditions and was also started in MS. To support such an approach, we aimed to investigate pain in MS with special emphasis on separating quantitative and qualitative aspects, and its interrelation to behavioral and physical aspects.Materials and methods: Pain intensity (NRS and quality (SES were measured in 38 consecutive outpatients with MS (mean age, 42.0 ± 11.5 years, 82% women. Pain-related behavior (FSR, health care utilization, bodily complaints (GBB-24 and fatigue (WEIMuS were assessed by questionnaires, and MS-related neurological impairment by a standardized neurological examination (EDSS.Results: Mean pain intensity was 4.0 (range, 0–10 and mean EDSS 3.7 (range, 0–8 in the overall sample. Currently present pain was reported by 81.6% of all patients. Disease duration and EDSS did not differ between patients with and without pain and were not correlated to quality or intensity of pain. Patients with pain had significantly higher scores of musculoskeletal complaints, but equal scores of exhaustion, gastrointestinal and cardiovascular complaints. Pain intensity correlated only with physical aspects, whereas quality of pain was additionally associated with increased avoidance, resignation and cognitive fatigue.Conclusion: As in other conditions, pain in MS must be assessed in a multidimensional way. Further research should be devoted to adapt existing models to a MS-specific model of pain.Keywords: pain intensity, quality of pain, pain

  13. Pediatric Fear-Avoidance Model of Chronic Pain: Foundation, Application and Future Directions

    Directory of Open Access Journals (Sweden)

    Gordon JG Asmundson

    2012-01-01

    Full Text Available The fear-avoidance model of chronic musculoskeletal pain has become an increasingly popular conceptualization of the processes and mechanisms through which acute pain can become chronic. Despite rapidly growing interest and research regarding the influence of fear-avoidance constructs on pain-related disability in children and adolescents, there have been no amendments to the model to account for unique aspects of pediatric chronic pain. A comprehensive understanding of the role of fear-avoidance in pediatric chronic pain necessitates understanding of both child/adolescent and parent factors implicated in its development and maintenance. The primary purpose of the present article is to propose an empirically-based pediatric fear-avoidance model of chronic pain that accounts for both child/adolescent and parent factors as well as their potential interactive effects. To accomplish this goal, the present article will define important fear-avoidance constructs, provide a summary of the general fear-avoidance model and review the growing empirical literature regarding the role of fear-avoidance constructs in pediatric chronic pain. Assessment and treatment options for children with chronic pain will also be described in the context of the proposed pediatric fear-avoidance model of chronic pain. Finally, avenues for future investigation will be proposed.

  14. Dynamic vehicle model for handling performance using experimental data

    Directory of Open Access Journals (Sweden)

    SangDo Na

    2015-11-01

    Full Text Available An analytical vehicle model is essential for the development of vehicle design and performance. Various vehicle models have different complexities, assumptions and limitations depending on the type of vehicle analysis. An accurate full vehicle model is essential in representing the behaviour of the vehicle in order to estimate vehicle dynamic system performance such as ride comfort and handling. An experimental vehicle model is developed in this article, which employs experimental kinematic and compliance data measured between the wheel and chassis. From these data, a vehicle model, which includes dynamic effects due to vehicle geometry changes, has been developed. The experimental vehicle model was validated using an instrumented experimental vehicle and data such as a step change steering input. This article shows a process to develop and validate an experimental vehicle model to enhance the accuracy of handling performance, which comes from precise suspension model measured by experimental data of a vehicle. The experimental force data obtained from a suspension parameter measuring device are employed for a precise modelling of the steering and handling response. The steering system is modelled by a lumped model, with stiffness coefficients defined and identified by comparing steering stiffness obtained by the measured data. The outputs, specifically the yaw rate and lateral acceleration of the vehicle, are verified by experimental results.

  15. Effects of perceived and exerted pain control on neural activity during pain relief in experimental heat hyperalgesia: a fMRI study.

    Science.gov (United States)

    Mohr, C; Leyendecker, S; Petersen, D; Helmchen, C

    2012-04-01

    Perceived control over pain can attenuate pain perception by mechanisms of endogenous pain control and emotional reappraisal irrespective of whether this control is exerted or only perceived. Self-initiated termination of pain elicits different expectations of subsequent pain relief as compared to perceived pain control. It is unknown whether and how this perceived vs. exerted control on pain differs and affects subsequent pain relief. Using fMRI, we studied two factors of pain control on pain relief: the (i) sense of control (perceived control but no execution) and (ii) the execution of control (exerted control). To account for the impact of factual execution of pain control on pain relief we applied bearable short and hardly bearable long contact-heat stimuli which were applied either controllable or not. Using controllability as factor, there was dissociable neural activity during pain relief: following the perceived control condition neural activity was found in the orbitofrontal and mediofrontal cortex and, following the exerted control condition, in the anterolateral and dorsolateral prefrontal cortex and posterior parietal cortex. We conclude that (i) pain controllability has an impact on pain relief and (ii) the prefrontal cortex shows dissociable neural activity during pain relief following exerted vs. perceived pain control. This might reflect the higher grade of uncertainty during pain relief following perceived pain control mediated by the orbitofrontal and medial prefrontal cortex and processes of working memory and updating expectations during pain relief following exerted control mediated by the lateral prefrontal cortex. © 2011 European Federation of International Association for the Study of Pain Chapters.

  16. Tailored skills training for practitioners to enhance assessment of prognostic factors for persistent and disabling back pain: four quasi-experimental single-subject studies.

    Science.gov (United States)

    Demmelmaier, Ingrid; Denison, Eva; Lindberg, Per; Åsenlöf, Pernilla

    2012-07-01

    The well-known gap between guidelines and behaviour in clinical practice calls for effective behaviour change interventions. One example showing this gap is physiotherapists' insufficient assessment of psychosocial prognostic factors in back pain (i.e., yellow flags). The present study aimed to evaluate an educational model by performing a tailored skills training intervention for caregivers and studying changes over time in physiotherapists' assessment of prognostic factors in telephone consultations. A quasi-experimental single-subject design over 36 weeks was used, with repeated measurements during baseline, intervention, and postintervention phases. Four physiotherapists in primary health care audiorecorded a total of 63 consultations with patients. The tailored intervention included individual goal setting, skills training, and feedback on performance. The primary outcome was the number of assessed prognostic factors (0-10). Changes were seen in all four participants. The amount of assessed prognostic factors increased from between 0 and 2 at baseline to between 6 and 10 at postintervention. Time spent on assessment of psychosocial factors increased, and time spent on discussions about biomedical pain symptoms decreased. Knowledge and biopsychosocial attitudes toward back pain were congruent with guidelines at inclusion and did not change markedly during the intervention. Self-efficacy for assessment of cognitive and emotional prognostic factors increased during the study phases. The results suggest that a tailored skills training intervention using behaviour change techniques, such as individual goal setting, skills training, and feedback on performance, is effective in producing change in specific clinical behaviours in physiotherapists.

  17. The efficacy of nerve growth factor antibody in a mouse model of neuropathic cancer pain

    OpenAIRE

    Miyagi, Masayuki; Ishikawa, Tetsuhiro; KAMODA, Hiroto; Suzuki, Miyako; Inoue, Gen; Sakuma, Yoshihiro; Oikawa, Yasuhiro; Uchida,Kentaro; SUZUKI, Takane; Takahashi, Kazuhisa; Takaso, Masashi; Ohtori, Seiji

    2016-01-01

    Neuropathic cancer pain is caused by tumors compressing the spinal nerve roots and is usually difficult to treat. The aim of current study was to determine the influence of NGF antibody on pain-related markers and behavior in a mouse model of neuropathic cancer pain. Twenty mice were used to model neuropathic cancer pain by applying murine sarcoma cells to their left sciatic nerve. Ten mice were sham operated. Two weeks after surgery, the murine sarcoma-affected mice were allocated randomly i...

  18. Efficacy and Safety of PPC-5650 on Experimental Rectal Pain in Patients with Irritable Bowel Syndrome

    DEFF Research Database (Denmark)

    Nielsen, Lecia Møller; Olesen, Anne Estrup; Andresen, Trine

    2015-01-01

    bowel syndrome (IBS). In patients with IBS, the aims of the study were: (1) to assess the efficacy of a single bolus of PPC-5650 locally applied in the rectum using multi-modal stimulations of the recto sigmoid and (2) to assess the safety profile of PPC-5650. The study was a randomized, double......PPC-5650 is a new pharmacological agent that can modulate acid-sensing ion channel activity, leading to a reduction in the pain signal under up-regulated conditions. The non-clinical programme for PPC-5650 supported a role for this novel agent in the treatment of pain in patients with irritable...

  19. The role of pain behaviour and family caregiver responses in the link between pain catastrophising and pain intensity : A moderated mediation model

    NARCIS (Netherlands)

    Mohammadi, Somayyeh; Dehghani, Mohsen; Sanderman, Robbert; Hagedoorn, Mariet

    2017-01-01

    Objectives: This study investigated the mediating role of pain behaviours in the association between pain catastrophising and pain intensity and explored the moderating role of family caregivers' responses to pain in the link between pain behaviours and pain intensity. Methods: The sample consisted

  20. The role of pain behaviour and family caregiver responses in the link between pain catastrophising and pain intensity: A moderated mediation model

    NARCIS (Netherlands)

    Mohammadi, Somayyeh; Dehghani, Mohsen; Sanderman, Robbert; Hagedoorn, Mariët

    2017-01-01

    Objectives: This study investigated the mediating role of pain behaviours in the association between pain catastrophising and pain intensity and explored the moderating role of family caregivers’ responses to pain in the link between pain behaviours and pain intensity. Methods: The sample consisted

  1. Back pain and backpacks in children : Biomedical or biopsychosocial model?

    NARCIS (Netherlands)

    Reneman, M.F.; Poels, B.J.J.; Geertzen, J.H.B.; Dijkstra, P.U.

    2006-01-01

    Public press, professional organisations and journals have been sending alarming messages about the rising prevalence of back pain in school age children. Carrying backpacks has been suggested as one of the key factors contributing to back pain in children. The basic assumption based on the

  2. Developing a model for measuring fear of pain in Norwegian samples: The Fear of Pain Questionnaire Norway

    DEFF Research Database (Denmark)

    Vambheim, Sara M; Lyby, Peter Solvoll; Aslaksen, Per M

    2017-01-01

    Fear of pain is highly correlated with pain report and physiological measures of arousal when pain is inflicted. The Fear of Pain Questionnaire III (FPQ-III) and The Fear of Pain Questionnaire Short Form (FPQ-SF) are self-report inventories developed for assessment of fear of pain (FOP). A previous...

  3. The oxidative response in the chronic constriction injury model of neuropathic pain.

    NARCIS (Netherlands)

    Tan, E.C.T.H.; Bahrami, S.; Kozlov, A.V.; Kurvers, H.A.J.M.; Laak, H.J. ter; Nohl, H.; Redl, H.; Goris, R.J.A.

    2009-01-01

    BACKGROUND: In the chronic constriction injury model of rat neuropathic pain, oxidative stress as well as antioxidants superoxide dismutase and reduced glutathione (GSH) are important determinants of neuropathological and behavioral consequences. Studies of the chronic constriction injury model

  4. Experimental comparison of models for ultrafast impact ionization is silicon

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Jepsen, Peter Uhd

    2016-01-01

    We compare experimentally the exponential and quadratic (Keldysh formula) impact ionization models using THz induced impact ionization in silicon. We demonstrate that the exponential model offers the best description of impact ionization process for ultrashort electric filed pulses....

  5. Cleavage of SNAP-25 ameliorates cancer pain in a mouse model of melanoma.

    Science.gov (United States)

    Olbrich, K; Costard, L; Möser, C V; Syhr, K M J; King-Himmelreich, T S; Wolters, M C; Schmidtko, A; Geisslinger, G; Niederberger, E

    2017-01-01

    Cancer pain is associated with increased pain sensitivity to noxious (hyperalgesia) and normally innocuous (allodynia) stimuli due to activation of nociceptors by tumour-derived mediators or tumour infiltration of nerves. The pain sensitization is accompanied by modifications in gene expression, but specifically regulated genes are largely unknown. The 25 kDa synaptosomal-associated protein (SNAP-25) is involved in chemical neurotransmission at the synaptic cleft. Its inhibition by Botulinum neurotoxin A (BoNT/A) has been associated with antinociceptive effects in migraine, inflammatory and neuropathic pain. However, its potential to reduce tumour-associated pain remains to be clarified. We applied a melanoma model of tumour pain in C57BL/6 mice and investigated SNAP-25 expression and regulation by qRT-PCR, Western Blot and immunofluorescence as well as tumour-associated mechanical allodynia with and without BoNT/A treatment. We found increased SNAP-25 expression in the dorsal root ganglia and the sciatic nerve. Intraplantar injection of BoNT/A induced the cleavage of SNAP-25 in these tissues and was associated with decreased mechanical allodynia after therapeutic treatment at early and late stages of tumour pain while the tumour size was not affected. Our data indicate that SNAP-25 plays a role in tumour pain but has no influence on the initiation and progression of skin cancer. Its cleavage inhibits the development of allodynia in the mouse melanoma model and might be useful as new therapeutic approach for the treatment of cancer pain. WHAT DOES THIS STUDY ADD?: SNAP-25 is differentially regulated during melanoma-induced tumour pain. Its cleavage by BoNT/A might be a suitable therapeutic option for tumour pain patients since tumour-associated pain can be strongly and significantly reduced after preventive and therapeutic BoNT/A treatment, respectively. © 2016 European Pain Federation - EFIC®.

  6. Studies on experimental models used for nutritional and biological ...

    African Journals Online (AJOL)

    The anatomical location for a successful implantation in order to reduce complications to the hearest minimum has been suggested . The maintenance of the implanted cannulae for the purpose of keeping the modified experimental model in perfect health is discussed. Key Words: Experimental Models, Nutritional Biological ...

  7. Current Studies of Acupuncture in Cancer-Induced Bone Pain Animal Models

    Directory of Open Access Journals (Sweden)

    Hee Kyoung Ryu

    2014-01-01

    Full Text Available Acupuncture is generally accepted as a safe and harmless treatment option for alleviating pain. To explore the pain mechanism, numerous animal models have been developed to simulate specific human pain conditions, including cancer-induced bone pain (CIBP. In this study, we analyzed the current research methodology of acupuncture for the treatment of CIBP. We electronically searched the PubMed database for animal studies published from 2000 onward using these search terms: (bone cancer OR cancer AND (pain OR analgesia AND (acupuncture OR pharmacopuncture OR bee venom. We selected articles that described cancer pain in animal models. We analyzed the methods used to induce cancer pain and the outcome measures used to assess the effects of acupuncture on CIBP in animal models. We reviewed articles that met our inclusion criteria. Injection of mammary cancer cells into the cavity of the tibia was the most frequently used method for inducing CIBP in the animal models. Among the eight selected studies, five studies demonstrated the effects of electroacupuncture on CIBP. The effects of acupuncture were assessed by measuring pain-related behavior. Future researches will be needed to ascertain the effectiveness of acupuncture for treating CIBP and to explore the specific mechanism of CIBP in animal models.

  8. Improving the physiological realism of experimental models

    NARCIS (Netherlands)

    Vinnakota, Kalyan C.; Cha, Chae Y.; Rorsman, Patrik; Balaban, Robert S.; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A.; Jeneson, Jeroen A. L.

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these

  9. Experimental Diabetes Mellitus in Different Animal Models

    Directory of Open Access Journals (Sweden)

    Amin Al-awar

    2016-01-01

    Full Text Available Animal models have historically played a critical role in the exploration and characterization of disease pathophysiology and target identification and in the evaluation of novel therapeutic agents and treatments in vivo. Diabetes mellitus disease, commonly known as diabetes, is a group of metabolic disorders characterized by high blood glucose levels for a prolonged time. To avoid late complications of diabetes and related costs, primary prevention and early treatment are therefore necessary. Due to its chronic symptoms, new treatment strategies need to be developed, because of the limited effectiveness of the current therapies. We overviewed the pathophysiological features of diabetes in relation to its complications in type 1 and type 2 mice along with rat models, including Zucker Diabetic Fatty (ZDF rats, BB rats, LEW 1AR1/-iddm rats, Goto-Kakizaki rats, chemically induced diabetic models, and Nonobese Diabetic mouse, and Akita mice model. The advantages and disadvantages that these models comprise were also addressed in this review. This paper briefly reviews the wide pathophysiological and molecular mechanisms associated with type 1 and type 2 diabetes, particularly focusing on the challenges associated with the evaluation and predictive validation of these models as ideal animal models for preclinical assessments and discovering new drugs and therapeutic agents for translational application in humans.

  10. Operationalizing Pain Treatment in the Biopsychosocial Model: Take a Daily "SWEM"--Socialize, Work, Exercise, Meditate.

    Science.gov (United States)

    Collen, Mark

    2015-09-01

    In the United States, chronic pain is often poorly treated at an exceedingly high cost. The use of the biomedical model to manage pain is frequently ineffective, and evidence suggests that the biopsychosocial (BPS) model is a better choice. A problem with the BPS model is that it has not been operationalized in terms of patient behavior. This commentary addresses that issue by suggesting that people with chronic pain and illness participate daily in four self-management health behaviors: socialize, work, exercise, and meditation, and discusses evidence that supports these recommendations. These self-management behaviors may decrease pain and thus reduce the need for pain medications and other medical interventions. Additional topics include patient adherence and health coaching.

  11. Neuromechanical responses after biofeedback training in participants with chronic low back pain: an experimental cohort study.

    Science.gov (United States)

    Pagé, Isabelle; Marchand, Andrée-Anne; Nougarou, François; O'Shaughnessy, Julie; Descarreaux, Martin

    2015-09-01

    The objective of this study was to evaluate changes in neuromechanical responses and clinical outcomes in chronic low back pain participants after 4 sessions of biofeedback training. Twenty-one participants took part in an electromyography biofeedback 4-session training program aimed at reducing lumbar paraspinal muscle activity during full trunk flexion. The sessions consisted of ~46 trunk flexion-extension divided into 5 blocks. The effects of training blocks and sessions on lumbar flexion-relaxation ratio and lumbopelvic ranges of motion were assessed. Changes in disability (Oswestry Disability Index), pain intensity (numerical rating scale), and fear of movement (Tampa Scale for Kinesiophobia) were also evaluated. Analyses of variance revealed a significant block effect for which an increase in the flexion-relaxation ratio and the lumbar range of motion between block 1 and the other blocks for sessions 1 and 2 (P Biofeedback training led to decreases in lumbar paraspinal muscle activity in full trunk flexion and increases in lumbopelvic range of motion in participants with chronic nonspecific low back pain. Although the neuromechanical changes were mostly observed at the early stage of the program, the presence of a decrease in the fear of movement suggests that the participants' initially limited ROMs may have been modulated by fear avoidance behaviors. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  12. Experimental model to induce obesity in rats

    National Research Council Canada - National Science Library

    Vinicius Von Diemen; Eduardo Neubarth Trindade; Manoel Roberto Maciel Trindade

    2006-01-01

    .... Obesity can be induced in animals by neuroendocrine, dietary or genetic changes. The most widely used models to induce obesity in rats are a lesion of the ventromedial hypothalamic nucleus (VMH...

  13. Optimization of experimental human leukemia models (review

    Directory of Open Access Journals (Sweden)

    D. D. Pankov

    2012-01-01

    Full Text Available Actual problem of assessing immunotherapy prospects including antigenpecific cell therapy using animal models was covered in this review.Describe the various groups of currently existing animal models and methods of their creating – from different immunodeficient mice to severalvariants of tumor cells engraftment in them. The review addresses the possibility of tumor stem cells studying using mouse models for the leukemia treatment with adoptive cell therapy including WT1. Also issues of human leukemia cells migration and proliferation in a mice withdifferent immunodeficiency degree are discussed. To assess the potential immunotherapy efficacy comparison of immunodeficient mouse model with clinical situation in oncology patients after chemotherapy is proposed.

  14. Pain Intervention for people with Dementia in nursing homes (PID): study protocol for a quasi-experimental nurse intervention.

    Science.gov (United States)

    Koppitz, Andrea; Bosshard, Georg; Blanc, Geneviève; Hediger, Hannele; Payne, Sheila; Volken, Thomas

    2017-04-21

    It is estimated that 19 to 83% of people with dementia suffer from pain that is inadequately treated in the last months of life. A large number of healthcare workers who care for these people in nursing homes lack appropriate expertise and may therefore not always recognise, assess and treat pain in those with dementia who have complex problems on time, properly and efficiently. The aim of this intervention trial is to identify care needs of people with dementia suffering from pain living in a nursing home. A quasi-experimental nurse-led intervention trial based on a convenience sample of four nursing homes in the Swiss Canton of Zurich examines the effects on dementia patients (n = 411), the healthcare institution and the qualification level of the healthcare workers compared to historical controls, using an event analysis and a multilevel analysis. Healthcare workers will be individually trained how to assess, intervene and evaluate acute and chronic pain. There are three data-monitoring cycles (T0, T1, T2) and two intervention cycles (I1, I2) with a total study duration of 425 days. There is also a process evaluation based on Dobbins analyses that analyse in particular the potentials for change in clinical practice of change agents. The aim of the intervention trial is to improve pain management strategies in older people with dementia in nursing homes. Clinically significant findings will be expected that will help reduce suffering in the sense of "total pain" for people with dementia. The joint intra- and interdisciplinary collaboration between practice and supply-oriented (nursing) research will have both a lasting effect on the efficiency measurement and provide scientifically sound results. Nursing homes can integrate the findings from the intervention trial into their internal quality control process. The potential for improvements can be directly influenced by the nursing home itself. Registration trial number: DRKS00009726 on DRKS, registered 10

  15. Experimental model of arteriovenous malformation in vitro using biological grafts

    Directory of Open Access Journals (Sweden)

    Sandu Aurelia Mihaela

    2015-06-01

    Full Text Available Introduction: Brain arteriovenous malformations (AVMs represent a serious health problem all around the world. Experimental models help to better understand the pathophysiology of these lesions. Experiment: We performed an experimental model of AVM using biological grafts, arteries and veins harvested from chicken wings at the elbow joint. We used 14 vessels and we performed 20 end-to-end anastomoses to create a nidus with a single feeding artery and a single draining vein. The system was irrigated with colored solution. The experiment was done according with law in force regarding experimental research activity. Conclusions: Experimental models allow us to understand the hemodynamics and predict the outcome of brain AVMs in humans. This experimental model is a useful tool in understanding the hemodynamic properties of brain AVMs. It is very useful in vascular anastomosis training

  16. An Empirical Investigation of a Biopsychosocial Model of Pain in Multiple Sclerosis.

    Science.gov (United States)

    Day, Melissa A; Ehde, Dawn M; Ward, L Charles; Hartoonian, Narineh; Alschuler, Kevin N; Turner, Aaron P; Kraft, George H; Jensen, Mark P

    2016-02-01

    Pain is a significant problem for many individuals with multiple sclerosis (MS). Pain is often associated with other MS symptoms (eg, physical, sensorimotor, cognitive declines), and both pain and MS symptoms are hypothesized to contribute to psychosocial problems (eg, depression), other symptoms (eg, fatigue, sleep disturbance), and functional impairments (eg, pain interference). On the basis of a biopsychosocial model, we sought to: (1) examine the associations between pain, MS symptoms, depression, psychosocial, and functional variables and (2) identify possible risk and protective factors associated with pain in MS. A cross-sectional survey was completed by 424 individuals with MS. Pain, MS symptoms, demographics, MS diagnostic factors, and psychosocial and functional variables were assessed. Data were analyzed by structural equation models. Participants were predominantly white (92%), middle-aged (mean=50.7 y), and female (80%). Results indicated that pain severity and depression accounted for >50% of the variance in pain interference. Although pain contributed minimally to fatigue and sleep quality, depression and MS symptoms predicted 49% of the variance in fatigue, and depression was largely responsible for the 40% of predicted variance in sleep quality. Identified risk factors for pain were low educational attainment and lack of a committed/marital relationship, even while controlling for diagnostic and other key demographic variables. Results highlight the importance of targeting interventions toward improving coping skills and social support within the context of pain and MS. Research is needed to determine whether effectively targeting depression in MS results in improvements of other critical psychosocial and physical functioning domains.

  17. An experimental comparison of modelling techniques for speaker ...

    Indian Academy of Sciences (India)

    Most of the existing modelling techniques for the speaker recognition task make an implicit assumption of sufficient data for speaker modelling and hence may lead to poor modelling under limited data condition. The present work gives an experimental evaluation of the modelling techniques like Crisp Vector Quantization ...

  18. Mechanisms of Electroacupuncture-Induced Analgesia on Neuropathic Pain in Animal Model

    Directory of Open Access Journals (Sweden)

    Woojin Kim

    2013-01-01

    Full Text Available Neuropathic pain remains as one of the most difficult clinical pain syndromes to treat. Electroacupuncture (EA, involving endogenous opioids and neurotransmitters in the central nervous system (CNS, is reported to be clinically efficacious in various fields of pain. Although multiple experimental articles were conducted to assess the effect of EA-induced analgesia, no review has been published to assess the efficacy and clarify the mechanism of EA on neuropathic pain. To this aim, this study was firstly designed to evaluate the EA-induced analgesic effect on neuropathic pain and secondly to guide and help future efforts to advance the neuropathic pain treatment. For this purpose, articles referring to the analgesic effect of acupuncture on neuropathic pain and particularly the work performed in our own laboratory were analyzed. Based on the articles reviewed, the role of spinal opioidergic, adrenergic, serotonergic, cholinergic, and GABAergic receptors in the mechanism of EA-induced analgesia was studied. The results of this research demonstrate that and opioid receptors, α2-adrenoreceptors, 5- and 5-HT3 serotonergic receptors, M1 muscarinic receptors, and and GABAergic receptors are involved in the mechanisms of EA-induced analgesia on neuropathic pain.

  19. Effect of Catechol-O-methyltransferase-gene (COMT) Variants on Experimental and Acute Postoperative Pain in 1,000 Women undergoing Surgery for Breast Cancer

    Science.gov (United States)

    Kambur, Oleg; Kaunisto, Mari A.; Tikkanen, Emmi; Leal, Suzanne M.; Ripatti, Samuli; Kalso, Eija A.

    2016-01-01

    Background Catechol-O-methyltransferase (COMT) metabolizes catecholamines in different tissues. Polymorphisms in COMT gene can attenuate COMT activity and increase sensitivity to pain. Human studies exploring the effect of COMT polymorphisms on pain sensitivity have mostly included small, heterogeneous samples and have ignored several important single nucleotide polymorphisms (SNPs). This study examines the effect of COMT polymorphisms on experimental and postoperative pain phenotypes in a large ethnically homogeneous female patient cohort. Methods Intensity of cold (+2–4°C) and heat (+48°C) pain and tolerance to cold pain were assessed in 1,000 patients scheduled for breast cancer surgery. Acute postoperative pain and oxycodone requirements were recorded. Twenty-two COMT SNPs were genotyped and their association with six pain phenotypes analyzed with linear regression. Results There was no association between any of the tested pain phenotypes and SNP rs4680. The strongest association signals were seen between rs165774 and heat pain intensity as well as rs887200 and cold pain intensity. In both cases, minor allele carriers reported less pain. Neither of these results remained significant after strict multiple testing corrections. When analyzed further, the effect of rs887200 was, however, shown to be significant and consistent throughout the cold pressure test. No evidence of association between the SNPs and postoperative oxycodone consumption was found. Conclusions SNPs rs887200 and rs165774 located in the untranslated regions of the gene had the strongest effects on pain sensitivity. Their effect on pain is described here for the first time. These results should be confirmed in further studies and the potential functional mechanisms of the variants studied. PMID:24343288

  20. The role of gender in the interaction between self-pain and the perception of pain in others.

    Science.gov (United States)

    Coll, Michel-Pierre; Budell, Lesley; Rainville, Pierre; Decety, Jean; Jackson, Philip L

    2012-07-01

    While self-pain motivates protective behaviors and self-oriented feelings, the perception of others' pain often motivates concern and prosocial behaviors toward the person suffering. The conflicting consequences of these 2 states raise the question of how pain is perceived in others when one is actually in pain. Two conflicting hypotheses could predict the interaction between these 2 signals: the threat value of pain hypothesis and the shared-representation model of pain empathy. Here, we asked 33 healthy volunteers exposed to acute experimental pain to judge the intensity of the pain felt by models expressing different levels of pain in video clips. Results showed that compared to a control warm stimulus, a stimulus causing self-pain increased the perception of others' pain for clips depicting male pain expressions but decreased the perceived intensity of female high pain expressions in both male and female participants. These results show that one's own pain state influences the perception of pain in others and that the gender of the person observed influences this interaction. By documenting the effects of self-pain on pain perception in others, this study provides a better understanding of the shared mechanisms between self-pain and others' pain processing. It could ultimately provide clues as to how the health status of health care professionals could affect their ability to assess their patients' pain. Copyright © 2012 American Pain Society. Published by Elsevier Inc. All rights reserved.

  1. Pro-inflammatory cytokines involvement in the hesperidin antihyperalgesic effects at peripheral and central levels in a neuropathic pain model.

    Science.gov (United States)

    Carballo-Villalobos, A I; González-Trujano, M E; Alvarado-Vázquez, N; López-Muñoz, F J

    2017-04-01

    Emerging evidence proposes a link between immune changes and pain, which is consistent with the inflammation theory and the increased incidence of neurodegenerative diseases. Flavonoids have long been used because of their anti-inflammatory potential activity and they are considered a promising alternative to alleviate neuropathic pain. The aim of this study was to investigate the antihyperalgesic effect of hesperidin and the presence of pro-inflammatory cytokines evaluated at peripheral and central levels in the chronic constriction injury as model of neuropathic pain in rats. Mechanical and thermal hyperalgesia were assessed in the aesthesiometer and plantar tests, respectively, as related to the presence of cytokines concentrations (TNF-α, IL-1β and IL-6) in sciatic nerve and segments of the spinal cord after 15 days chronic constriction injury model in rats receiving vehicle or hesperidin. Antihyperalgesic response of hesperidin (100 mg/kg) was associated to the presence of cytokines mainly at several sections of the spinal cord suggesting not only peripheral but also its involvement in central sensitization in the experimental neuropathic pain.

  2. Hysteretic behavior of a belt tensioner: modeling and experimental investigation

    OpenAIRE

    Michon, Guilhem; Manin, Lionel; Dufour, Regis

    2005-01-01

    In this paper we describe the modeling of the hysteretic behavior of belt tensioners. An initial experimental device is composed only of the tensioner by using forcing frequencies, preloads and deflection amplitudes. It permits the identification of the parameters of the restoring force model used. Comparison of the measured and predicted force deflection loops of the tensioner subjected to large deflections permits preliminary validation of the model.The second experimental device consists o...

  3. The effects of anger and sadness on clinical pain reports and experimentally-induced pain thresholds in women with and without fibromyalgia.

    NARCIS (Netherlands)

    Middendorp, H. van; Lumley, M.A.; Jacobs, J.W.G.; Bijlsma, J.W.J.; Geenen, R.

    2010-01-01

    OBJECTIVE: Negative emotions are commonly experienced in fibromyalgia and may affect pain. This study examined the effects of anger and sadness on clinical pain reports and on pain threshold and tolerance in response to electrical stimulation in women with and without fibromyalgia. METHODS: In an

  4. Experimental Measurement, Analysis and Modelling of Dependency ...

    African Journals Online (AJOL)

    We propose a direct method of measurement of the total emissivity of opaque samples on a range of temperature around the ambient one. The method rests on the modulation of the temperature of the sample and the infra-red signal processing resulting from the surface of the sample we model the total emissivity obtained ...

  5. A theory-based educational intervention targeting nurses' attitudes and knowledge concerning cancer-related pain management: a study protocol of a quasi-experimental design.

    Science.gov (United States)

    Borglin, Gunilla; Gustafsson, Markus; Krona, Hans

    2011-09-23

    Pain is one of the most frequent problems among patients diagnosed with cancer. Despite the availability of effective pharmacological treatments, this group of patients often receives less than optimal treatment. Research into nurses' pain management highlights certain factors, such as lack of knowledge and attitudes and inadequate procedures for systematic pain assessment, as common barriers to effective pain management. However, educational interventions targeting nurses' pain management have shown promise. As cancer-related pain is also known to have a negative effect on vital aspects of the patient's life, as well as being commonly associated with problems such as sleep, fatigue, depression and anxiety, further development of knowledge within this area is warranted. A quasi-experimental study design will be used to investigate whether the implementation of guidelines for systematic daily pain assessments following a theory-based educational intervention will result in an improvement in knowledge and attitude among nurses. A further aim is to investigate whether the intervention that targets nurses' behaviour will improve hospital patients' perception of pain. Data regarding nurses' knowledge and attitudes to pain (primary outcome), patient perception regarding pain (secondary outcome), together with socio-demographic variables, will be collected at baseline and at four weeks and 12 weeks following the intervention. Nursing care is nowadays acknowledged as an increasingly complicated activity and "nursing complexity is such that it can be seen as the quintessential complex intervention." To be able to change and improve clinical practice thus requires multiple points of attack appropriate to meet complex challenges. Consequently, we expect the theory-based intervention used in our quasi-experimental study to improve care as well as quality of life for this group of patients and we also envisage that evidence-based guidelines targeting this patient group's pain

  6. A theory-based educational intervention targeting nurses' attitudes and knowledge concerning cancer-related pain management: A study protocol of a quasi-experimental design

    Directory of Open Access Journals (Sweden)

    Gustafsson Markus

    2011-09-01

    Full Text Available Abstract Background Pain is one of the most frequent problems among patients diagnosed with cancer. Despite the availability of effective pharmacological treatments, this group of patients often receives less than optimal treatment. Research into nurses' pain management highlights certain factors, such as lack of knowledge and attitudes and inadequate procedures for systematic pain assessment, as common barriers to effective pain management. However, educational interventions targeting nurses' pain management have shown promise. As cancer-related pain is also known to have a negative effect on vital aspects of the patient's life, as well as being commonly associated with problems such as sleep, fatigue, depression and anxiety, further development of knowledge within this area is warranted. Methods/design A quasi-experimental study design will be used to investigate whether the implementation of guidelines for systematic daily pain assessments following a theory-based educational intervention will result in an improvement in knowledge and attitude among nurses. A further aim is to investigate whether the intervention that targets nurses' behaviour will improve hospital patients' perception of pain. Data regarding nurses' knowledge and attitudes to pain (primary outcome, patient perception regarding pain (secondary outcome, together with socio-demographic variables, will be collected at baseline and at four weeks and 12 weeks following the intervention. Discussion Nursing care is nowadays acknowledged as an increasingly complicated activity and "nursing complexity is such that it can be seen as the quintessential complex intervention." To be able to change and improve clinical practice thus requires multiple points of attack appropriate to meet complex challenges. Consequently, we expect the theory-based intervention used in our quasi-experimental study to improve care as well as quality of life for this group of patients and we also envisage that

  7. Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron.

    Directory of Open Access Journals (Sweden)

    Sofia Louca Jounger

    Full Text Available The aim of this study was to investigate experimentally if 5-HT3 single nucleotide polymorphisms (SNP contribute to pain perception and efficacy of the 5-HT3-antagonist granisetron and sex differences. Sixty healthy participants were genotyped regarding HTR3A (rs1062613 and HTR3B (rs1176744. First, pain was induced by bilateral hypertonic saline injections (HS, 5.5%, 0.2 mL into the masseter muscles. Thirty min later the masseter muscle on one side was pretreated with 0.5 mL granisetron (1 mg/mL and on the other side with 0.5 mL placebo (isotonic saline followed by another HS injection (0.2 mL. Pain intensity, pain duration, pain area and pressure pain thresholds (PPTs were assessed after each injection. HS evoked moderate pain, with higher intensity in the women (P = 0.023, but had no effect on PPTs. None of the SNPs influenced any pain variable in general, but compared to men, the pain area was larger in women carrying the C/C (HTR3A (P = 0.015 and pain intensity higher in women with the A/C alleles (HTR3B (P = 0.019. Pre-treatment with granisetron reduced pain intensity, duration and area to a lesser degree in women (P < 0.05, but the SNPs did not in general influence the efficacy of granisetron. Women carrying the C/T & T/T (HTR3A genotype had less reduction of pain intensity (P = 0.041 and area (P = 0.005, and women with the C/C genotype (HTR3B had less reduction of pain intensity (P = 0.030, duration (P = 0.030 and area compared to men (P = 0.017. In conclusion, SNPs did not influence experimental muscle pain or the effect of granisetron on pain variables in general, but there were some sex differences in pain variables that seem to be influenced by genotypes. However, due to the small sample size further research is needed before any firm conclusions can be drawn.

  8. Use of Animal Models in Understanding Cancer-induced Bone Pain

    Directory of Open Access Journals (Sweden)

    Lauren M. Slosky

    2015-01-01

    Full Text Available Many common cancers have a propensity to metastasize to bone. Although malignancies often go undetected in their native tissues, bone metastases produce excruciating pain that severely compromises patient quality of life. Cancer-induced bone pain (CIBP is poorly managed with existing medications, and its multifaceted etiology remains to be fully elucidated. Novel analgesic targets arise as more is learned about this complex and distinct pain state. Over the past two decades, multiple animal models have been developed to study CIBP's unique pathology and identify therapeutic targets. Here, we review animal models of CIBP and the mechanistic insights gained as these models evolve. Findings from immunocompromised and immunocompetent host systems are discussed separately to highlight the effect of model choice on outcome. Gaining an understanding of the unique neuromolecular profile of cancer pain through the use of appropriate animal models will aid in the development of more effective therapeutics for CIBP.

  9. New experimental model for training in videosurgery Novo modelo experimental para treinamento em videocirurgia

    Directory of Open Access Journals (Sweden)

    Danilo Malta Batista

    2012-10-01

    Full Text Available PURPOSE: To develop a new experimental model of lower cost for training in videosurgery. METHODS: This project was performed at the Nucleus of Experimental Surgery of the Bahiana School of Medicine and Public Health, based on previous models described in the literature and under the supervision of the full professor of Operative Technique and Experimental Surgery II. It was made a model cube-shaped, made of wood, with holes distributed in various locations, rubber stoppers for the holes and lined externally with carpet, and internally with laminate. RESULTS: The new experimental model is of low cost and reproduces quite faithfully several videosurgical procedures. CONCLUSION: Medical schools interested in the subject may adopt the new model for training in videosurgery without the need of high costs for making and using these models.OBJETIVO: Desenvolver um novo modelo experimental de baixo custo para treinamento em videocirurgia MÉTODOS: Este projeto foi conduzido no Núcleo de Cirurgia Experimental da Escola Bahiana de Medicina e Saúde Pública, baseado em modelos prévios descritos na literatura e sob a supervisão do professor titular de Técnica Operatória e Cirurgia Experimental II. Foi feito um modelo em formato de cubo, de madeira, com furos distribuídos em vários locais, tampas de borracha para os orifícios e forrado externamente com carpete e internamente com laminado. RESULTADOS: O novo modelo experimental desenvolvido é de baixo custo e reproduz de forma bastante fiel diversos procedimentos videocirúrgicos. CONCLUSÃO: Faculdades médicas interessadas no tema poderão adotar o novo modelo para o treinamento em videocirurgia sem que sejam necessários gastos elevados para a confecção e o uso desses modelos.

  10. Experimental pain ratings and reactivity of cortisol and soluble tumor necrosis factor-α receptor II following a trial of hypnosis: results of a randomized controlled pilot study.

    Science.gov (United States)

    Goodin, Burel R; Quinn, Noel B; Kronfli, Tarek; King, Christopher D; Page, Gayle G; Haythornthwaite, Jennifer A; Edwards, Robert R; Stapleton, Laura M; McGuire, Lynanne

    2012-01-01

    Current evidence supports the efficacy of hypnosis for reducing the pain associated with experimental stimulation and various acute and chronic conditions; however, the mechanisms explaining how hypnosis exerts its effects remain less clear. The hypothalamic-pituitary-adrenal (HPA) axis and pro-inflammatory cytokines represent potential targets for investigation given their purported roles in the perpetuation of painful conditions; yet, no clinical trials have thus far examined the influence of hypnosis on these mechanisms. Healthy participants, highly susceptible to the effects of hypnosis, were randomized to either a hypnosis intervention or a no-intervention control. Using a cold pressor task, assessments of pain intensity and pain unpleasantness were collected prior to the intervention (Pre) and following the intervention (Post) along with pain-provoked changes in salivary cortisol and the soluble tumor necrosis factor-α receptor II (sTNFαRII). Compared with the no-intervention control, data analyses revealed that hypnosis significantly reduced pain intensity and pain unpleasantness. Hypnosis was not significantly associated with suppression of cortisol or sTNFαRII reactivity to acute pain from Pre to Post; however, the effect sizes for these associations were medium-sized. Overall, the findings from this randomized controlled pilot study support the importance of a future large-scale study on the effects of hypnosis for modulating pain-related changes of the HPA axis and pro-inflammatory cytokines. Wiley Periodicals, Inc.

  11. Different experimental approaches in modelling cataractogenesis

    Science.gov (United States)

    Kyselova, Zuzana

    2010-01-01

    Cataract, the opacification of eye lens, is the leading cause of blindness worldwide. At present, the only remedy is surgical removal of the cataractous lens and substitution with a lens made of synthetic polymers. However, besides significant costs of operation and possible complications, an artificial lens just does not have the overall optical qualities of a normal one. Hence it remains a significant public health problem, and biochemical solutions or pharmacological interventions that will maintain the transparency of the lens are highly required. Naturally, there is a persistent demand for suitable biological models. The ocular lens would appear to be an ideal organ for maintaining culture conditions because of lacking blood vessels and nerves. The lens in vivo obtains its nutrients and eliminates waste products via diffusion with the surrounding fluids. Lens opacification observed in vivo can be mimicked in vitro by addition of the cataractogenic agent sodium selenite (Na2SeO3) to the culture medium. Moreover, since an overdose of sodium selenite induces also cataract in young rats, it became an extremely rapid and convenient model of nuclear cataract in vivo. The main focus of this review will be on selenium (Se) and its salt sodium selenite, their toxicological characteristics and safety data in relevance of modelling cataractogenesis, either under in vivo or in vitro conditions. The studies revealing the mechanisms of lens opacification induced by selenite are highlighted, the representatives from screening for potential anti-cataract agents are listed. PMID:21217865

  12. The structural model of pain, cognitive strategies, and negative emotions in functional gastrointestinal disorders

    Directory of Open Access Journals (Sweden)

    Mina Mazaheri

    2016-01-01

    Full Text Available Background: Patients with functional gastrointestinal disorders (FGIDs may use specific coping strategies. We intend to provide a mediating role of the relationship between pain (intensity and acceptance, cognitive emotion regulation strategies, and negative emotions in patients with FGIDs. Materials and Methods: Participants were 176 inpatients, all experiencing significant FGIDs symptomatology as confirmed by gastroenterologists. Patients completed data on cognitive emotion regulation questionnaire, short form of depression, anxiety, stress scale, chronic pain acceptance questionnaire-revised, and pain intensity scale. Data were analyzed using structural equation modeling method. Results: The pain intensity had significantly direct effect on cognitive emotion regulation strategies and indirect effect on negative emotions. Besides, the mediating role of negative emotions in the relationship between the strategies and pain acceptance were supported, whereas indirect relationships between pain intensity and acceptance through cognitive strategies were not confirmed. Conclusion: The results of the study emphasize the role of pain intensity in the development of negative emotions through cognitive strategies and the role of the strategies in pain acceptance through negative emotions. In fact, cognitive strategies to be related to pain and emotions.

  13. The role of fluoxetine on macrophage function in chronic pain (Experimental study in Balb/c mice

    Directory of Open Access Journals (Sweden)

    Dwi Pudjonarko

    2015-11-01

    Full Text Available Chronic pain raises stress conditions such as depression that can lower the cellular immunity. Fluoxetine is an antidepressant  used as an adjuvant in pain management but no one has been linked it with the body immune system. The objectives of this research were to proof the benefits of fluoxetine in  preventing degradation of macrophage function in chronic pain by measuring the macrophage phagocytic index , macrophage NO levels and the liver bacterial count in BALB/c mice infected with Listeria Monocytogenes.A Post Test - Only Control Group Design was conducted using 28 male mice strain BALB /c, age 8-10 weeks. The control group (C, mice got the same standard feed as the other groups. Chronic pain group (P, mice were injected with 20μL intraplantar CFA on day-1. Pain + fluoxetine early group (PFE were treated with P + fluoxetine 5 mg / kg ip day-1, the 4th, the 7th and the 10th, while the Pain + fluoxetine late group (PFL were treated with P + fluoxetine 5 mg / kg ip on day 7th and 10th. All mice were injected with 104 live Listeria monocytogenes iv on day 8th. Termination was performed on day 13th. Differences within groups  were analyzed using  One-way ANOVA and Kruskall Wallis, whereas the correlation of variables were analyzed using  Pearson's product moment. The experimental results showed that The macrophage phagocytic index and NO macrophage level (pg/mL in PFE group(2,24±1,013; 0,24±0,239 was higher than than P group (1,68±0,920; 0,21±0,263 and there was no different in the macrophage phagocytic index of PFE group compared to C group (p=0,583; p=0,805. In PFL group (4,32±1,459; 0,54±0,294 the macrophage phagocytic index as well as NO macrophage level (pg/mL was higher than P group (1,68±0,920; 0,21±0,263 with p=0,002; p=0,017. P group Bacterial count (log cfu/gram (2,30±0,849 was significantly higher than C group(1,15±0,223 (p=0,007, while PFE group bacterial count (1,96±0,653 and PFL group bacterial count (1,84±0

  14. Experimentally testing the standard cosmological model

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-11-01

    The standard model of cosmology, the big bang, is now being tested and confirmed to remarkable accuracy. Recent high precision measurements relate to the microwave background; and big bang nucleosynthesis. This paper focuses on the latter since that relates more directly to high energy experiments. In particular, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard cosmology scenario. Discussion is presented on the improved light element observational data as well as the improved neutron lifetime data. alternate nucleosynthesis scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, {Omega}{sub b}, remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the standard model conclusion that {Omega}{sub b} {approximately} 0.06. This latter point is the deriving force behind the need for non-baryonic dark matter (assuming {Omega}{sub total} = 1) and the need for dark baryonic matter, since {Omega}{sub visible} < {Omega}{sub b}. Recent accelerator constraints on non-baryonic matter are discussed, showing that any massive cold dark matter candidate must now have a mass M{sub x} {approx gt} 20 GeV and an interaction weaker than the Z{sup 0} coupling to a neutrino. It is also noted that recent hints regarding the solar neutrino experiments coupled with the see-saw model for {nu}-masses may imply that the {nu}{sub {tau}} is a good hot dark matter candidate. 73 refs., 5 figs.

  15. Tesla coil theoretical model and experimental verification

    OpenAIRE

    Voitkans, Janis; Voitkans, Arnis

    2014-01-01

    Abstract – In this paper a theoretical model of a Tesla coil operation is proposed. Tesla coil is described as a long line with distributed parameters in a single-wired format, where the line voltage is measured against electrically neutral space. It is shown that equivalent two-wired scheme can be found for a single-wired scheme and already known long line theory can be applied to a Tesla coil. Formulas for calculation of voltage in a Tesla coil by coordinate and calculation of resonance fre...

  16. Modulation of Brain Electroencephalography Oscillations by Electroacupuncture in a Rat Model of Postincisional Pain

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2013-01-01

    Full Text Available The present study aimed to investigate how ongoing brain rhythmical oscillations changed during the postoperative pain and whether electroacupuncture (EA regulated these brain oscillations when it relieved pain. We established a postincisional pain model of rats with plantar incision to mimic the clinical pathological pain state, tested the analgesic effects of EA, and recorded electroencephalography (EEG activities before and after the EA application. By analysis of power spectrum and bicoherence of EEG, we found that in rats with postincisional pain, ongoing activities at the delta-frequency band decreased, while activities at theta-, alpha-, and beta-frequency bands increased. EA treatment on these postincisional pain rats decreased the power at high-frequency bands especially at the beta-frequency band and reversed the enhancement of the cross-frequency coupling strength between the beta band and low-frequency bands. After searching for the PubMed, our study is the first time to describe that brain oscillations are correlated with the processing of spontaneous pain information in postincisional pain model of rats, and EA could regulate these brain rhythmical frequency oscillations, including the power and cross-frequency couplings.

  17. Modulation of Brain Electroencephalography Oscillations by Electroacupuncture in a Rat Model of Postincisional Pain

    Science.gov (United States)

    Wang, Jing; Wang, Jing; Li, Xuezhu; Li, Duan; Li, Xiao-Li; Han, Ji-Sheng; Wan, You

    2013-01-01

    The present study aimed to investigate how ongoing brain rhythmical oscillations changed during the postoperative pain and whether electroacupuncture (EA) regulated these brain oscillations when it relieved pain. We established a postincisional pain model of rats with plantar incision to mimic the clinical pathological pain state, tested the analgesic effects of EA, and recorded electroencephalography (EEG) activities before and after the EA application. By analysis of power spectrum and bicoherence of EEG, we found that in rats with postincisional pain, ongoing activities at the delta-frequency band decreased, while activities at theta-, alpha-, and beta-frequency bands increased. EA treatment on these postincisional pain rats decreased the power at high-frequency bands especially at the beta-frequency band and reversed the enhancement of the cross-frequency coupling strength between the beta band and low-frequency bands. After searching for the PubMed, our study is the first time to describe that brain oscillations are correlated with the processing of spontaneous pain information in postincisional pain model of rats, and EA could regulate these brain rhythmical frequency oscillations, including the power and cross-frequency couplings. PMID:23710210

  18. Multivariate prognostic modeling of persistent pain following lumbar discectomy.

    LENUS (Irish Health Repository)

    Hegarty, Dominic

    2013-03-04

    Persistent postsurgical pain (PPSP) affects between 10% and 50% of surgical patients, the development of which is a complex and poorly understood process. To date, most studies on PPSP have focused on specific surgical procedures where individuals do not suffer from chronic pain before the surgical intervention. Individuals who have a chronic nerve injury are likely to have established peripheral and central sensitization which may increase the risk of developing PPSP. Concurrent analyses of the possible factors contributing to the development of PPSP following lumbar discectomy have not been examined.

  19. Mathematical Models and the Experimental Analysis of Behavior

    Science.gov (United States)

    Mazur, James E.

    2006-01-01

    The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make…

  20. Inducible nitric oxide synthase inhibition by 1400W limits pain hypersensitivity in a neuropathic pain rat model.

    Science.gov (United States)

    Staunton, C A; Barrett-Jolley, R; Djouhri, L; Thippeswamy, T

    2018-02-13

    Peripheral neuropathic pain (PNP) resulting from injury or dysfunction to a peripheral nerve, is a major health problem affecting 7-8% of the population. It is inadequately controlled by current drugs, and is characterized by pain hypersensitivity which is believed to be due to sensitization of peripheral and CNS neurons by various inflammatory mediators. Here we examined, in a rat model of PNP: a) whether reducing levels of nitric oxide (NO), with 1400 W, a highly selective inhibitor of inducible NO synthase (iNOS), would prevent/attenuate pain hypersensitivity, and b) the effects of 1400 W on plasma levels of several cytokines that are secreted post iNOS upregulation during chronic pain states. The L5-spinal nerve axotomy (SNA) model of PNP was used, and 1400 W (20 mg kg -1 ) administered intraperitoneally at 8 hour intervals for three days starting at 18 hours post-SNA. Changes in plasma concentrations of 12 cytokines in SNA rats treated with 1400 W were examined using multiplex ELISA. SNA rats developed behavioural signs of mechanical and heat hypersensitivity. Compared with the vehicle/control, 1400 W significantly: (a) limited development of mechanical hypersensitivity at 66 hours post-SNA, as well as heat hypersensitivity at 42 hours and at several time-points tested thereafter, and (b) increased the plasma concentrations of IL-1α, IL-1β, and IL-10 in the SNA rats. The findings suggest that 1400 W may exert its analgesic effects by reducing iNOS and altering the balance between the pro-inflammatory (IL-1β and IL-1α) and anti-inflammatory (IL-10) cytokines and that therapies targeting NO or its enzymes may be effective for the treatment of PNP. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Microplasticity of MMC. Experimental results and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Maire, E. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Lormand, G. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Gobin, P.F. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Fougeres, R. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France))

    1993-11-01

    The microplastic behavior of several MMC is investigated by means of tension and compression tests. This behavior is assymetric : the proportional limit is higher in tension than in compression but the work hardening rate is higher in compression. These differences are analysed in terms of maxium of the Tresca's shear stress at the interface (proportional limit) and of the emission of dislocation loops during the cooling (work hardening rate). On another hand, a model is proposed to calculate the value of the yield stress, describing the composite as a material composed of three phases : inclusion, unaffected matrix and matrix surrounding the inclusion having a gradient in the density of the thermally induced dilocations. (orig.).

  2. Experimental investigation of a flapping wing model

    Energy Technology Data Exchange (ETDEWEB)

    Hubel, Tatjana Y.; Tropea, Cameron [Technische Universitaet Darmstadt, Fachgebiet Stroemungslehre und Aerodynamik, Darmstadt (Germany)

    2009-05-15

    The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle. (orig.)

  3. Neck/shoulder and back pain in new graduate nurses: A growth mixture modeling analysis.

    Science.gov (United States)

    Lövgren, Malin; Gustavsson, Petter; Melin, Bo; Rudman, Ann

    2014-04-01

    Although it is well known that musculoskeletal disorders are common among registered nurses, little longitudinal research has been conducted to examine this problem from nursing education to working life. The aim was to investigate the prevalence and incidence of neck/shoulder and back pain in nursing students in their final semester, and one and two years after graduation. Furthermore, to identify common trajectories of neck/shoulder and back pain, and explore sociodemographic and lifestyle-related factors, contextual factors and health outcome that might be characteristic of individuals in the various trajectories. Longitudinal study following nursing students from their final year of studies, with follow-ups one and two years after graduation. Nursing students who graduated from the 26 universities providing undergraduate nursing education in Sweden 2002 were invited to participate (N=1700). Of those asked, 1153 gave their informed consent. The participants answered postal surveys at yearly intervals. Descriptive statistics were used to analyze prevalence and incidence of pain, and growth mixture modeling was applied to identify different homogeneous clusters of individuals following similar trajectories in pain development across time. The prevalence of neck/shoulder and back pain remained constant over time (around 50% for neck/shoulder pain and just over 40% for back pain). Six different development trajectories for each symptom were found, reflecting patterns of stable pain levels or variation in levels over time: one symptom-free group, two decreasing pain groups, two increasing pain groups, and one chronic pain group. With few exceptions, the same factors (sex, children, chronic disease, working overtime, work absence, sickness presence, physical load, depression, self-rated health, sleep quality and muscular tension) were associated with neck/shoulder and back pain trajectories. Different types of physical load characterized new nurses with neck

  4. The effect of the application of manual pressure before the administration of intramuscular injections on students' perceptions of postinjection pain: a semi-experimental study.

    Science.gov (United States)

    Öztürk, Deniz; Baykara, Zehra Gocmen; Karadag, Ayise; Eyikara, Evrim

    2017-06-01

    To evaluate the efficacy of applying manual pressure before intramuscular injection and compare it with the standard injection technique in terms of reducing the young adult student's postinjection pain. The administration of intramuscular injections is a procedure performed by nurses and one that causes anxiety and pain for the patient. Nurses have ethical and legal obligations to mitigate injection-related pain and the nurses' use of effective pain management not only provides physical comfort to the patients, but also improves the patients' experience. Comparative experimental study. This study was conducted with first-year university students (n = 123) who were scheduled for hepatitis A and hepatitis B vaccination via deltoid muscle injection. Students were randomly assigned to the groups. Comparison group students (n = 60) were given an injection using the conventional method, that is without manual pressure being applied prior to the injection. The experimental group students (n = 63) received manual pressure at the vaccination site immediately before injection for a period of 10 seconds. The two techniques were used randomly. The subjects were given pressure to the injection site, and perceived pain intensity was measured using Numerical Rating Scale. Findings demonstrate that students experienced significantly less pain when they received injections with manual pressure compared with the standard injection technique. The postinjection average pain score in the comparison group was higher than that in the experimental group (p pressure to the injection site before intramuscular injections reduces postinjection pain intensity in young adult students (p pressure to the adult's intramuscular injection site is recommended. Applying pressure to the injection area is a simple and cost-effective method to reduce the pain associated with injection. © 2016 John Wiley & Sons Ltd.

  5. Statistical approach for uncertainty quantification of experimental modal model parameters

    DEFF Research Database (Denmark)

    Luczak, M.; Peeters, B.; Kahsin, M.

    2014-01-01

    . This paper aims at a systematic approach for uncertainty quantification of the parameters of the modal models estimated from experimentally obtained data. Statistical analysis of modal parameters is implemented to derive an assessment of the entire modal model uncertainty measure. Investigated structures...... estimates obtained from vibration experiments. Modal testing results are influenced by numerous factors introducing uncertainty to the measurement results. Different experimental techniques applied to the same test item or testing numerous nominally identical specimens yields different test results...

  6. Participation of neuronal nitric oxide synthase in experimental neuropathic pain induced by sciatic nerve transection

    Directory of Open Access Journals (Sweden)

    M. Chacur

    2010-04-01

    Full Text Available Nerve injury leads to a neuropathic pain state that results from central sensitization. This phenomenom is mediated by NMDA receptors and may involve the production of nitric oxide (NO. In this study, we investigated the expression of the neuronal isoform of NO synthase (nNOS in the spinal cord of 3-month-old male, Wistar rats after sciatic nerve transection (SNT. Our attention was focused on the dorsal part of L3-L5 segments receiving sensory inputs from the sciatic nerve. SNT resulted in the development of neuropathic pain symptoms confirmed by evaluating mechanical hyperalgesia (Randall and Selitto test and allodynia (von Frey hair test. Control animals did not present any alteration (sham-animals. The selective inhibitor of nNOS, 7-nitroindazole (0.2 and 2 µg in 50 µL, blocked hyperalgesia and allodynia induced by SNT. Immunohistochemical analysis showed that nNOS was increased (48% by day 30 in the lumbar spinal cord after SNT. This increase was observed near the central canal (Rexed’s lamina X and also in lamina I-IV of the dorsal horn. Real-time PCR results indicated an increase of nNOS mRNA detected from 1 to 30 days after SNT, with the highest increase observed 1 day after injury (1469%. Immunoblotting confirmed the increase of nNOS in the spinal cord between 1 and 15 days post-lesion (20%, reaching the greatest increase (60% 30 days after surgery. The present findings demonstrate an increase of nNOS after peripheral nerve injury that may contribute to the increase of NO production observed after peripheral neuropathy.

  7. Behavioral cues to expand a pain model of the cognitively impaired elderly in long-term care

    National Research Council Canada - National Science Library

    Burfield, Allison H; Wan, Thomas T H; Sole, Mary Lou; Cooper, James W

    2012-01-01

    The purpose of this study was to determine the relationship between hypothesized pain behaviors in the elderly and a measurement model of pain derived from the Minimum Data Set-Resident Assessment Instrument (MDS-RAI) 2.0 items...

  8. In silico simulations of experimental protocols for cardiac modeling.

    Science.gov (United States)

    Carro, Jesus; Rodriguez, Jose Felix; Pueyo, Esther

    2014-01-01

    A mathematical model of the AP involves the sum of different transmembrane ionic currents and the balance of intracellular ionic concentrations. To each ionic current corresponds an equation involving several effects. There are a number of model parameters that must be identified using specific experimental protocols in which the effects are considered as independent. However, when the model complexity grows, the interaction between effects becomes increasingly important. Therefore, model parameters identified considering the different effects as independent might be misleading. In this work, a novel methodology consisting in performing in silico simulations of the experimental protocol and then comparing experimental and simulated outcomes is proposed for parameter model identification and validation. The potential of the methodology is demonstrated by validating voltage-dependent L-type calcium current (ICaL) inactivation in recently proposed human ventricular AP models with different formulations. Our results show large differences between ICaL inactivation as calculated from the model equation and ICaL inactivation from the in silico simulations due to the interaction between effects and/or to the experimental protocol. Our results suggest that, when proposing any new model formulation, consistency between such formulation and the corresponding experimental data that is aimed at being reproduced needs to be first verified considering all involved factors.

  9. Influência da naloxona e metisergida sobre o efeito analgésico do laser em baixa intensidade em modelo experimental de dor Influencia de la naloxona y la metisergida sobre el efecto analgésico del láser en baja intensidad en modelo experimental de dolor Influence of naloxone and methysergide on the analgesic effects of low-level laser in an experimental pain model

    Directory of Open Access Journals (Sweden)

    André Peres e Serra

    2010-06-01

    ; Luz no coherente; LPT + Naloxona y LPT + Metisergida. RESULTADOS: La fototerapia con láser en baja intensidad demostró ser un método analgésico eficaz, mientras que el uso de la fuente de luz no coherente no demostró poseer ningún efecto analgésico. El uso de naloxona bloqueó el efecto analgésico del LPT, mientras que el uso de metisergida no afectó la analgesia del LPT. CONCLUSIONES: La LPT en los parámetros utilizados tuvo un efecto analgésico. La analgesia de la LPT es mediada por receptores opióides periféricos. La LPT parece que no interactúa con los receptores serotoninérgicos periféricos.BACKGROUND AND OBJECTIVES: Although the mechanism of action of laser phototherapy (LPT is not known, it is a promising analgesic method. The aim of this study was to evaluate whether the action of LPT depends on the activation of peripheral opioid or serotonergic receptors. METHOD: Inflammatory pain was induced through the injection of carrageenin in the left posterior paw of male Wistar rats. The InGaAIP visible laser diode (660 nm with fluency of 2.5 J.cm-2 was used. Von Frey filaments were used to analyze mechanical hyperalgesia. Animals were separated into five groups: Carrageenin; Laser (LPT; Non-coherent light; LPT + Naloxone; and LPT + Methysergide. RESULTS: Low-Level Laser phototherapy proved to be an effective analgesic method, while non-coherent light did not show a similar effect. The use of naloxone blocked the analgesic effect of LPT, while methysergide did not affect LPT-induced analgesia. CONCLUSIONS: According to the parameter used in this study, LPT produced analgesia. Analgesia induced by laser phototherapy is mediated by peripheral opioid receptors. Laser phototherapy does not seem to interact with peripheral serotonergic receptors.

  10. Perceiving pain in others: validation of a dual processing model.

    Science.gov (United States)

    McCrystal, Kalie N; Craig, Kenneth D; Versloot, Judith; Fashler, Samantha R; Jones, Daniel N

    2011-05-01

    Accurate perception of another person's painful distress would appear to be accomplished through sensitivity to both automatic (unintentional, reflexive) and controlled (intentional, purposive) behavioural expression. We examined whether observers would construe diverse behavioural cues as falling within these domains, consistent with cognitive neuroscience findings describing activation of both automatic and controlled neuroregulatory processes. Using online survey methodology, 308 research participants rated behavioural cues as "goal directed vs. non-goal directed," "conscious vs. unconscious," "uncontrolled vs. controlled," "fast vs. slow," "intentional (deliberate) vs. unintentional," "stimulus driven (obligatory) vs. self driven," and "requiring contemplation vs. not requiring contemplation." The behavioural cues were the 39 items provided by the PROMIS pain behaviour bank, constructed to be representative of the diverse possibilities for pain expression. Inter-item correlations among rating scales provided evidence of sufficient internal consistency justifying a single score on an automatic/controlled dimension (excluding the inconsistent fast vs. slow scale). An initial exploratory factor analysis on 151 participant data sets yielded factors consistent with "controlled" and "automatic" actions, as well as behaviours characterized as "ambiguous." A confirmatory factor analysis using the remaining 151 data sets replicated EFA findings, supporting theoretical predictions that observers would distinguish immediate, reflexive, and spontaneous reactions (primarily facial expression and paralinguistic features of speech) from purposeful and controlled expression (verbal behaviour, instrumental behaviour requiring ongoing, integrated responses). There are implicit dispositions to organize cues signaling pain in others into the well-defined categories predicted by dual process theory. Copyright © 2011 International Association for the Study of Pain. Published by

  11. [Empathy for pain: A novel bio-psychosocial-behavioral laboratory animal model].

    Science.gov (United States)

    Chen, Jun; Li, Zhen; Lv, Yun-Fei; Li, Chun-Li; Wang, Yan; Wang, Rui-Rui; Geng, Kai-Wen; He, Ting

    2015-12-25

    Empathy, a basic prosocial behavior, is referred to as an ability to understand and share others' emotional state. Generally, empathy is also a social-behavioral basis of altruism. In contrast, impairment of empathy development may be associated with autism, narcissism, alexithymia, personality disorder, schizophrenia and depression. Thus, study of the brain mechanisms of empathy has great importance to not only scientific and clinical advances but also social harmony. However, research on empathy has long been avoided due to the fact that it has been considered as a distinct feature of human beings from animals, leading to paucity of knowledge in the field. In 2006, a Canadian group from McGill University found that a mouse in pain could be shared by its paired cagemate, but not a paired stranger, showing decreased pain threshold and increased pain responses through emotional contagion while they were socially interacting. In 2014, we further found that a rat in pain could also be shared by its paired cagemate 30 min after social interaction, showing long-term decreased pain threshold and increased pain responses, suggesting persistence of empathy for pain (empathic memory). We also mapped out that the medial prefrontal cortex, including the anterior cingulate cortex, prelimbic cortex and infralimbic cortex, is involved in empathy for pain in rats, suggesting that a neural network may be associated with development of pain empathy in the CNS. In the present brief review, we give a brief outline of the advances and challenges in study of empathy for pain in humans and animals, and try to provide a novel bio-psychosocial-behavioral model for study of pain and its emotional comorbidity using laboratory animals.

  12. Pain acceptance and personal control in pain relief in two maternity care models: a cross-national comparison of Belgium and the Netherlands

    Science.gov (United States)

    2010-01-01

    Background A cross-national comparison of Belgian and Dutch childbearing women allows us to gain insight into the relative importance of pain acceptance and personal control in pain relief in 2 maternity care models. Although Belgium and the Netherlands are neighbouring countries sharing the same language, political system and geography, they are characterised by a different organisation of health care, particularly in maternity care. In Belgium the medical risks of childbirth are emphasised but neutralised by a strong belief in the merits of the medical model. Labour pain is perceived as a needless inconvenience easily resolved by means of pain medication. In the Netherlands the midwifery model of care defines childbirth as a normal physiological process and family event. Labour pain is perceived as an ally in the birth process. Methods Women were invited to participate in the study by independent midwives and obstetricians during antenatal visits in 2004-2005. Two questionnaires were filled out by 611 women, one at 30 weeks of pregnancy and one within the first 2 weeks after childbirth either at home or in a hospital. However, only women having a hospital birth without obstetric intervention (N = 327) were included in this analysis. A logistic regression analysis has been performed. Results Labour pain acceptance and personal control in pain relief render pain medication use during labour less likely, especially if they occur together. Apart from this general result, we also find large country differences. Dutch women with a normal hospital birth are six times less likely to use pain medication during labour, compared to their Belgian counterparts. This country difference cannot be explained by labour pain acceptance, since - in contrast to our working hypothesis - Dutch and Belgian women giving birth in a hospital setting are characterised by a similar labour pain acceptance. Our findings suggest that personal control in pain relief can partially explain the

  13. Effects of Hemibridge with Ball and Balloon Exercise on Forced Expiratory Volume and Pain in Patients with Chronic Low Back Pain: An Experimental Study

    OpenAIRE

    Jorida Fernandes; Akshay Chougule

    2017-01-01

    Background and objectives: Suboptimal breathing patterns and impairments of posture and trunk stability are often associated with musculoskeletal complaints such as low back pain. Respiration is also affected by poor neuromuscular control of core muscles. Immediate effects of hemibridge with ball and balloon exercise has been studied on chronic pain in athlete population. Objective: To evaluate the effects of hemibridge with ball and balloon exercise on pain, forced expiratory volume and func...

  14. High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, F.M.; Castro, L.L.; Ferreira, R.T.; Pires, P.A.; Vanderlinde, F.A.; Medeiros, M.A. [Departamento de Ciências Fisiológicas, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2012-08-24

    The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

  15. Clinical Prediction Model and Tool for Assessing Risk of Persistent Pain After Breast Cancer Surgery

    DEFF Research Database (Denmark)

    Meretoja, Tuomo J; Andersen, Kenneth Geving; Bruce, Julie

    2017-01-01

    Purpose Persistent pain after breast cancer surgery is a well-recognized problem, with moderate to severe pain affecting 15% to 20% of women at 1 year from surgery. Several risk factors for persistent pain have been recognized, but tools to identify high-risk patients and preventive interventions...... are missing. The aim was to develop a clinically applicable risk prediction tool. Methods The prediction models were developed and tested using three prospective data sets from Finland (n = 860), Denmark (n = 453), and Scotland (n = 231). Prediction models for persistent pain of moderate to severe intensity...... at 1 year postoperatively were developed by logistic regression analyses in the Finnish patient cohort. The models were tested in two independent cohorts from Denmark and Scotland by assessing the areas under the receiver operating characteristics curves (ROC-AUCs). The outcome variable was moderate...

  16. Analgesic efficacy of CR4056, a novel imidazoline-2 receptor ligand, in rat models of inflammatory and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Ferrari F

    2011-04-01

    Full Text Available Flora Ferrari1, Simonetta Fiorentino1, Laura Mennuni1, Paolo Garofalo1, Ornella Letari1, Stefano Mandelli2, Antonio Giordani3, Marco Lanza1, Gianfranco Caselli11Department of Pharmacology and Toxicology; 2Department of Medicinal Chemistry; 3R&D Chemistry Drug Development and OS, Rottapharm S.p.A., Monza (MB, ItalyAbstract: Two decades of investigations have failed to unequivocally clarify the functions and the molecular nature of imidazoline-2 receptors (I2R. However, there is robust pharmacological evidence for the functional modulation of monoamino oxidase (MAO and other important enzyme activities by I2 site ligands. Some compounds of this class proved to be active experimental tools in preventing both experimental pain and opioid tolerance and dependence. Unfortunately, even though these compounds bind with high potency to central I2 sites, they fail to represent a valid clinical opportunity due to their pharmacokinetic, selectivity or side-effects profile. This paper presents the preclinical profile of a novel I2 ligand (2-phenyl-6-(1H-imidazol-1ylquinazoline; [CR4056] that selectively inhibits the activity of human recombinant MAO-A in a concentration-dependent manner. A sub-chronic four day oral treatment of CR4056 increased norepinephrine (NE tissue levels both in the rat cerebral cortex (63.1% ± 4.2%; P<0.05 and lumbar spinal cord (51.3% ± 6.7%; P < 0.05. In the complete Freund's adjuvant (CFA rat model of inflammatory pain, CR4056 was found to be orally active (ED50 = 5.8 mg/kg, by mouth [p.o.]. In the acute capsaicin model, CR4056 completely blocked mechanical hyperalgesia in the injured hind paw (ED50 = 4.1 mg/kg, p.o.; ED100 = 17.9 mg/kg, p.o.. This effect was dose-dependently antagonized by the non-selective imidazoline I2/α2 antagonist idazoxan. In rat models of neuropathic pain, oral administration of CR4056 significantly attenuated mechanical hyperalgesia and allodynia. In summary, the present study suggests a novel

  17. The use of Alloxan and Streptozotocin in Experimental Diabetes Models

    Directory of Open Access Journals (Sweden)

    Zehra Kurçer

    2012-06-01

    Full Text Available Diabetes is a chronic metabolic disease which leads to several acute and chronic complications, morbidity and mortality, and decreased lifespan and quality of life. Therefore, in research studies that aim to enlighten the pathogenesis of diabetes and investigate possible treatment strategies, experimental animal models of diabetes provide many advantages to the investigator. Models of diabetes obtained by chemical induction, diet, surgical manipulations or combination thereof and also new genetically modified animal models are some of the experimental models. Alloxan and streptozotocin (STZ, which are toxic glucose analogues that preferentially accumulate in pancreatic beta cells, are widely used toxic agents to induce experimental diabetes in animals. This review gives an overview on the use of alloxan and STZ to induce chemical diabetes models with reference to their mechanisms, utilizable doses, advantages and disadvantages in diabetes research. Turk Jem 2012; 16: 34-40

  18. The traditional Japanese medicine hangeshashinto alleviates oral ulcer-induced pain in a rat model.

    Science.gov (United States)

    Hitomi, Suzuro; Ono, Kentaro; Yamaguchi, Kiichiro; Terawaki, Kiyoshi; Imai, Ryota; Kubota, Kunitsugu; Omiya, Yuji; Hattori, Tomohisa; Kase, Yoshio; Inenaga, Kiyotoshi

    2016-06-01

    Recent studies have demonstrated that mouthwash made with the traditional Japanese medicine hangeshashinto exhibits anti-inflammatory action and alleviates oral mucositis scores, including pain complaints, in patients undergoing chemoradiotherapy. However, no study has demonstrated the mechanism underlying how hangeshashinto provides pain relief in oral ulcers. The analgesic effects on pain-related behaviors following the topical application of hangeshashinto were evaluated in an oral ulcer rat model treated with acetic acid using recently developed methods. Indomethacin, the representative anti-inflammatory agent, was intraperitoneally administered. The tissue permeability of the oral mucosa was histologically evaluated after applying the fluorescent substance FluoroGold. The topical application of hangeshashinto in ulcerative oral mucosa suppressed mechanical pain hypersensitivity over 60 min, without any effects on healthy mucosa. The same drug application also inhibited oral ulcer-induced spontaneous pain. Indomethacin administration failed to block the mechanical pain hypersensitivity, though it did largely block spontaneous pain. Topical anesthesia with lidocaine showed hyposensitivity to mechanical stimulation in healthy mucosa. In the ulcer regions in which the oral epithelial barrier was destroyed, deep parenchyma was stained with FluoroGold, in contrast to healthy oral mucosa, in which staining was limiting to the superficial site. Hangeshashinto leads to long-lasting analgesic effects, specifically in the ulcer region by destroying the epithelial barrier. Hangeshashinto alleviates oral ulcer-induced pain in inflammation-dependent and/or independent manner. Copyright © 2016. Published by Elsevier Ltd.

  19. Uncovering the influence of social skills and psychosociological factors on pain sensitivity using structural equation modeling.

    Science.gov (United States)

    Tanaka, Yoichi; Nishi, Yuki; Nishi, Yuki; Osumi, Michihiro; Morioka, Shu

    2017-01-01

    Pain is a subjective emotional experience that is influenced by psychosociological factors such as social skills, which are defined as problem-solving abilities in social interactions. This study aimed to reveal the relationships among pain, social skills, and other psychosociological factors by using structural equation modeling. A total of 101 healthy volunteers (41 men and 60 women; mean age: 36.6±12.7 years) participated in this study. To evoke participants' sense of inner pain, we showed them images of painful scenes on a PC screen and asked them to evaluate the pain intensity by using the visual analog scale (VAS). We examined the correlation between social skills and VAS, constructed a hypothetical model based on results from previous studies and the current correlational analysis results, and verified the model's fit using structural equation modeling. We found significant positive correlations between VAS and total social skills values, as well as between VAS and the "start of relationships" subscales. Structural equation modeling revealed that the values for "start of relationships" had a direct effect on VAS values (path coefficient =0.32, psocial support. The results indicated that extroverted people are more sensitive to inner pain and tend to get more social support and maintain a better psychological condition.

  20. The β-lactam clavulanic acid mediates glutamate transport-sensitive pain relief in a rat model of neuropathic pain.

    Science.gov (United States)

    Kristensen, P J; Gegelashvili, G; Munro, G; Heegaard, A M; Bjerrum, O J

    2018-02-01

    Following nerve injury, down-regulation of astroglial glutamate transporters (GluTs) with subsequent extracellular glutamate accumulation is a key factor contributing to hyperexcitability within the spinal dorsal horn. Some β-lactam antibiotics can up-regulate GluTs, one of which, ceftriaxone, displays analgesic effects in rodent chronic pain models. Here, the antinociceptive actions of another β-lactam clavulanic acid, which possesses negligible antibiotic activity, were compared with ceftriaxone in rats with chronic constriction injury (CCI)-induced neuropathic pain. In addition, the protein expression of glutamate transporter-1 (GLT1), its splice variant GLT1b and glutamate-aspartate transporter (GLAST) was measured in the spinal cord of CCI rats. Finally, protein expression of the same GluTs was evaluated in cultured astrocytes obtained from rodents and humans. Repeated injection of ceftriaxone or clavulanic acid over 10 days alleviated CCI-induced mechanical hypersensitivity, whilst clavulanic acid was additionally able to affect the thermal hypersensitivity. In addition, clavulanic acid up-regulated expression of GLT1b within the spinal cord of CCI rats, whereas ceftriaxone failed to modulate expression of any GluTs in this model. However, both clavulanic acid and ceftriaxone up-regulated GLT1 expression in rat cortical and human spinal astrocyte cultures. Furthermore, clavulanic acid increased expression of GLT1b and GLAST in rat astrocytes in a dose-dependent manner. Thus, clavulanic acid up-regulates GluTs in cultured rodent- and human astroglia and alleviates CCI-induced hypersensitivity, most likely through up-regulation of GLT1b in spinal dorsal horn. Chronic dosing of clavulanic acid alleviates neuropathic pain in rats and up-regulates glutamate transporters both in vitro and in vivo. Crucially, a similar up-regulation of glutamate transporters in human spinal astrocytes by clavulanic acid supports the development of novel

  1. Statistical Models for the Analysis of Zero-Inflated Pain Intensity Numeric Rating Scale Data.

    Science.gov (United States)

    Goulet, Joseph L; Buta, Eugenia; Bathulapalli, Harini; Gueorguieva, Ralitza; Brandt, Cynthia A

    2017-03-01

    Pain intensity is often measured in clinical and research settings using the 0 to 10 numeric rating scale (NRS). NRS scores are recorded as discrete values, and in some samples they may display a high proportion of zeroes and a right-skewed distribution. Despite this, statistical methods for normally distributed data are frequently used in the analysis of NRS data. We present results from an observational cross-sectional study examining the association of NRS scores with patient characteristics using data collected from a large cohort of 18,935 veterans in Department of Veterans Affairs care diagnosed with a potentially painful musculoskeletal disorder. The mean (variance) NRS pain was 3.0 (7.5), and 34% of patients reported no pain (NRS = 0). We compared the following statistical models for analyzing NRS scores: linear regression, generalized linear models (Poisson and negative binomial), zero-inflated and hurdle models for data with an excess of zeroes, and a cumulative logit model for ordinal data. We examined model fit, interpretability of results, and whether conclusions about the predictor effects changed across models. In this study, models that accommodate zero inflation provided a better fit than the other models. These models should be considered for the analysis of NRS data with a large proportion of zeroes. We examined and analyzed pain data from a large cohort of veterans with musculoskeletal disorders. We found that many reported no current pain on the NRS on the diagnosis date. We present several alternative statistical methods for the analysis of pain intensity data with a large proportion of zeroes. Published by Elsevier Inc.

  2. [Development and therapy of the pain syndrome of reflex sympathetic dystrophy. Clinical expression, experimental investigations, and new pathophysiological considerations.].

    Science.gov (United States)

    Blumberg, H

    1988-09-01

    Reflex sympathetic dystrophy (RSD) is a disease of the extremities that can be elicited by different factors, occurring at different sites (e.g., trauma, herpes zoster, myocardial infarction). Independently of its etiology, however, the clinical symptoms of RSD are found most often in distal parts of the extremities affected (hand or foot). In a generalized distribution pattern, the following signs, representing a triad of autonomic, motoric and sensory disturbances, are commonly observed in these regions: 1. dysregulation of blood flow to the skin and of sweating, together with diffuse swelling, 2. impairment of movement and muscular strength; 3. diffuse sensory skin disturbances and spontaneous pain of ariable character (e.g., burning, throbbing, aching, shooting). Pain sensation is generally diffuse; in most cases it is deep and less often, superficial (probably representing bone or skin pain, respectively). This triad occurs at the very onset of RSD. If the distribution pattern is generalized, it can be used as a diagnostic criterion for RSD. Our experimental results support the idea of disturbances of skin blood flow related to abnormal vasoconstrictor outflow. This assumption is primarily based on two observations: 1. 73% of 97 RSD patients (upper extremity affected) showed systematic side differences in fingertip temperatures at room temperature. All points measured on the affected side had higher (n=51) or lower (n= 20) temperature values than corresponding sites on the healthy extremity. Such systematic side differences were found only in 16% out of 79 healthy subjects (pRSD patients as compared with 18 healthy subjects (2.5 degrees vs 0.9 degrees C,pRSD (e.g. proximal or distal trauma, partial nerve lesion). In most cases the predominant symptoms of RSD are swelling of a distal extremity and spontaneous pain. It is presumed that these symptoms are primarily initiated by a noxious event, which can be recognized as a common factor in the history of the

  3. A comprehensive examination of the model underlying acceptance and commitment therapy for chronic pain.

    Science.gov (United States)

    Vowles, Kevin E; Sowden, Gail; Ashworth, Julie

    2014-05-01

    The therapeutic model underlying Acceptance and Commitment Therapy (ACT) is reasonably well-established as it applies to chronic pain. Several studies have examined measures of single ACT processes, or subsets of processes, and have almost uniformly indicated reliable relations with patient functioning. To date, however, no study has performed a comprehensive examination of the entire ACT model, including all of its component processes, as it relates to functioning. The present study performed this examination in 274 individuals with chronic pain presenting for an assessment appointment. Participants completed a battery of self-report questionnaires, assessing multiple aspects of the ACT model, as well as pain intensity, disability, and emotional distress. Initial exploratory factor analyses examined measures of the ACT model and measures of patient functioning separately with each analysis identifying three factors. Next, the fit of a model including ACT processes on the one hand and patient functioning on the other was examined using Structural Equation Modeling. Overall model fit was acceptable and indicated moderate correlations among the ACT processes themselves, as well as significant relations with pain intensity, emotional distress, and disability. These analyses build on the existing literature by providing, to our knowledge, the most comprehensive evaluation of the ACT theoretical model in chronic pain to date. Copyright © 2014. Published by Elsevier Ltd.

  4. Using an experimental model for the study of therapeutic touch Uso de un modelo experimental para estudio sobre el toque terapéutico Utilização de um modelo experimental para estudo sobre o toque terapêutico

    OpenAIRE

    Daniella Soares dos Santos; Ilda Estéfani Ribeiro Marta; Evelin Capellari Cárnio; Andreza Urba de Quadros; Thiago Mattar Cunha; Emilia Campos de Carvalho

    2013-01-01

    OBJECTIVE: to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. METHOD: this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic...

  5. Animal models of bone cancer pain: systematic review and meta-analyses.

    Science.gov (United States)

    Currie, Gillian L; Delaney, Ada; Bennett, Michael I; Dickenson, Anthony H; Egan, Kieren J; Vesterinen, Hanna M; Sena, Emily S; Macleod, Malcolm R; Colvin, Lesley A; Fallon, Marie T

    2013-06-01

    Pain can significantly decrease the quality of life of patients with advanced cancer. Current treatment strategies often provide inadequate analgesia and unacceptable side effects. Animal models of bone cancer pain are used in the development of novel pharmacological approaches. Here we conducted a systematic review and meta-analysis of publications describing in vivo modelling of bone cancer pain in which behavioural, general health, macroscopic, histological, biochemical, or electrophysiological outcomes were reported and compared to appropriate controls. In all, 150 publications met our inclusion criteria, describing 38 different models of bone cancer pain. Reported methodological quality was low; only 31% of publications reported blinded assessment of outcome, and 11% reported random allocation to group. No publication reported a sample size calculation. Studies that reported measures to reduce bias reported smaller differences in behavioural outcomes between tumour-bearing and control animals, and studies that presented a statement regarding a conflict of interest reported larger differences in behavioural outcomes. Larger differences in behavioural outcomes were reported in female animals, when cancer cells were injected into either the tibia or femur, and when MatLyLu prostate or Lewis Lung cancer cells were used. Mechanical-evoked pain behaviours were most commonly reported; however, the largest difference was observed in spontaneous pain behaviours. In the spinal cord astrocyte activation and increased levels of Substance P receptor internalisation, c-Fos, dynorphin, tumor necrosis factor-α and interleukin-1β have been reported in bone cancer pain models, suggesting several potential therapeutic targets. However, the translational impact of animal models on clinical pain research could be enhanced by improving methodological quality. Copyright © 2013. Published by Elsevier B.V.

  6. Design and Implementation of an Experimental Segway Model

    Science.gov (United States)

    Younis, Wael; Abdelati, Mohammed

    2009-03-01

    The segway is the first transportation product to stand, balance, and move in the same way we do. It is a truly 21st-century idea. The aim of this research is to study the theory behind building segway vehicles based on the stabilization of an inverted pendulum. An experimental model has been designed and implemented through this study. The model has been tested for its balance by running a Proportional Derivative (PD) algorithm on a microprocessor chip. The model has been identified in order to serve as an educational experimental platform for segways.

  7. Experimental and modeling studies of mass transfer in ...

    African Journals Online (AJOL)

    Gaining a better understanding of mass transfer problems in encapsulated cell systems and in tissue engineering requires both experimental investigations and mathematical modelling. Specific mass transfer studies are reviewed including oxygen transfer in immobilised animal cell culture systems, modelling of ...

  8. TO STUDY THE EFFECT OF PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION ON BACK MUSCLE STRENGTH, PAIN AND QUALITY OF LIFE IN SUBJECTS WITH CHRONIC LOW BACK PAIN AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Trupti Jadeja

    2015-10-01

    Full Text Available Background: Back pain is a prevalent and expensive problem in society. 60-80% of people will suffer at least one episode of low back pain sometime in their lives and 30-40% of these will experience low back pain each year. Therefore the need of the following study is to see the effect of proprioceptive neuromuscular facilitation on back muscle strength, pain and QOL in subjects with Chronic Low Back Pain. Methods: Ethical approval was taken before study. Forty patients with chronic low back pain (28 male, 12 female were included in the study and divided into two groups each containing 20 subjects. All the participants were signed written consent after being informed in detail about the study. Group A has been given the proprioceptive neuromuscular facilitation exercises including Rhythmic Stabilization (RST and Combination of Isotonics (COI and Conventional back exercises. Group B was given conventional back exercises only. Outcome measures were taken at the end of one month i.e. after the treatment protocol. VAS, SF-36Questionnaire and Core stability gradation were taken in both groups. Results: There is significant improvement in VAS score in both groups but Group A was having more significant improvement than Group B. Also there is significant improvement in core stability grading and SF 36 score in Group A. Conclusion: It is concluded that proprioceptive neuromuscular facilitation exercises on back is effective in reducing pain and improving core muscle strength in subjects with Chronic Low Back Pain.

  9. Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model

    DEFF Research Database (Denmark)

    Ravn, Pernille; Secher, EL; Skram, U

    2013-01-01

    Opioid therapy is associated with the development of tolerance and paradoxically increased sensitivity to pain. It has been suggested that buprenorphine is associated with a higher antihyperalgesia/analgesia ratio than μ-opioid receptor agonists. The primary outcome of this study was therefore...... to investigate relative differences in antihyperalgesia and analgesia effects between morphine and buprenorphine in an inflammatory pain model in volunteers. The secondary outcome was to examine the relationship between pain sensitivity and opioid-induced effects on analgesia, antihyperalgesia, and descending...

  10. Uncovering the influence of social skills and psychosociological factors on pain sensitivity using structural equation modeling

    Science.gov (United States)

    Tanaka, Yoichi; Nishi, Yuki; Nishi, Yuki; Osumi, Michihiro; Morioka, Shu

    2017-01-01

    Pain is a subjective emotional experience that is influenced by psychosociological factors such as social skills, which are defined as problem-solving abilities in social interactions. This study aimed to reveal the relationships among pain, social skills, and other psychosociological factors by using structural equation modeling. A total of 101 healthy volunteers (41 men and 60 women; mean age: 36.6±12.7 years) participated in this study. To evoke participants’ sense of inner pain, we showed them images of painful scenes on a PC screen and asked them to evaluate the pain intensity by using the visual analog scale (VAS). We examined the correlation between social skills and VAS, constructed a hypothetical model based on results from previous studies and the current correlational analysis results, and verified the model’s fit using structural equation modeling. We found significant positive correlations between VAS and total social skills values, as well as between VAS and the “start of relationships” subscales. Structural equation modeling revealed that the values for “start of relationships” had a direct effect on VAS values (path coefficient =0.32, p<0.01). In addition, the “start of relationships” had both a direct and an indirect effect on psychological factors via social support. The results indicated that extroverted people are more sensitive to inner pain and tend to get more social support and maintain a better psychological condition. PMID:28979161

  11. Linking Experimental Characterization and Computational Modeling in Microstructural Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, Melik Cumhar [Univ. of Pittsburgh, PA (United States)

    2002-06-01

    It is known that by controlling microstructural development, desirable properties of materials can be achieved. The main objective of our research is to understand and control interface dominated material properties, and finally, to verify experimental results with computer simulations. In order to accomplish this objective, we studied the grain growth in detail with experimental techniques and computational simulations. We obtained 5170-grain data from an Aluminum-film (120μm thick) with a columnar grain structure from the Electron Backscattered Diffraction (EBSD) measurements. Experimentally obtained starting microstructure and grain boundary properties are input for the three-dimensional grain growth simulation. In the computational model, minimization of the interface energy is the driving force for the grain boundary motion. The computed evolved microstructure is compared with the final experimental microstructure, after annealing at 550 ºC. Two different measures were introduced as methods of comparing experimental and computed microstructures. Modeling with anisotropic mobility explains a significant amount of mismatch between experiment and isotropic modeling. We have shown that isotropic modeling has very little predictive value. Microstructural evolution in columnar Aluminum foils can be correctly modeled with anisotropic parameters. We observed a strong similarity between grain growth experiments and anisotropic three-dimensional simulations.

  12. Development of a fault test experimental facility model using Matlab

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Iraci Martinez; Moraes, Davi Almeida, E-mail: martinez@ipen.br, E-mail: dmoraes@dk8.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The Fault Test Experimental Facility was developed to simulate a PWR nuclear power plant and is instrumented with temperature, level and pressure sensors. The Fault Test Experimental Facility can be operated to generate normal and fault data, and these failures can be added initially small, and their magnitude being increasing gradually. This work presents the Fault Test Experimental Facility model developed using the Matlab GUIDE (Graphical User Interface Development Environment) toolbox that consists of a set of functions designed to create interfaces in an easy and fast way. The system model is based on the mass and energy inventory balance equations. Physical as well as operational aspects are taken into consideration. The interface layout looks like a process flowchart and the user can set the input variables. Besides the normal operation conditions, there is the possibility to choose a faulty variable from a list. The program also allows the user to set the noise level for the input variables. Using the model, data were generated for different operational conditions, both under normal and fault conditions with different noise levels added to the input variables. Data generated by the model will be compared with Fault Test Experimental Facility data. The Fault Test Experimental Facility theoretical model results will be used for the development of a Monitoring and Fault Detection System. (author)

  13. Linking Experimental Characterization and Computational Modeling in Microstructural Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, Melik Cumhur [Univ. of California, Berkeley, CA (United States)

    2002-06-01

    It is known that by controlling microstructural development, desirable properties of materials can be achieved. The main objective of our research is to understand and control interface dominated material properties, and finally, to verify experimental results with computer simulations. In order to accomplish this objective, we studied the grain growth in detail with experimental techniques and computational simulations. We obtained 5170-grain data from an Aluminum-film (120μm thick) with a columnar grain structure from the Electron Backscattered Diffraction (EBSD) measurements. Experimentally obtained starting microstructure and grain boundary properties are input for the three-dimensional grain growth simulation. In the computational model, minimization of the interface energy is the driving force for the grain boundary motion. The computed evolved microstructure is compared with the final experimental microstructure, after annealing at 550 ºC. Two different measures were introduced as methods of comparing experimental and computed microstructures. Modeling with anisotropic mobility explains a significant amount of mismatch between experiment and isotropic modeling. We have shown that isotropic modeling has very little predictive value. Microstructural evolution in columnar Aluminum foils can be correctly modeled with anisotropic parameters. We observed a strong similarity

  14. Can a theory-based educational intervention change nurses' knowledge and attitudes concerning cancer pain management? A quasi-experimental design.

    Science.gov (United States)

    Gustafsson, Markus; Borglin, Gunilla

    2013-08-19

    Registered Nurses (RNs) play an important role in caring for patients suffering from cancer pain. A lack of knowledge regarding pain management and the RNs' own perception of cancer pain could act as barriers to effective pain management. Educational interventions that target RNs' knowledge and attitudes have proved promising. However, an intervention consisting of evidence-based practice is a multifaceted process and demands behavioural and cognitive changes to sustain the effects of the intervention. Therefore, our study aimed to investigate if a theory-based educational intervention could change RNs' knowledge and attitudes to cancer pain and pain management, both four and 12 weeks after the start of the intervention. A quasi-experimental design with non-equivalent control groups was used. The primary outcome was measured using a modified version of the instrument Nurses' Knowledge and Attitudes Survey Regarding Pain (NKAS) at baseline, four weeks and 12 weeks after the start of the intervention to evaluate its persistence. The intervention's educational curriculum was based on the principles of Ajzen's Theory of Planned Behaviour and consisted of interactive learning activities conducted in workshops founded on evidence-based knowledge. The RN's own experiences from cancer pain management were used in the learning process. The theory-based educational intervention aimed at changing RNs knowledge and attitudes regarding cancer pain management measured by primary outcome NKAS resulted in a statistical significant (ptheory-based educational intervention focused at RNs can be effective in changing RN's knowledge and attitudes regarding cancer pain management. However, the high number of dropouts between baseline and four weeks needs to be taken into account when evaluating our findings. Finally, this kind of theory-based educational intervention with interactive learning activities has been sparsely researched and needs to be evaluated further in larger projects

  15. Analgesic Effect of Recombinant GABAergic Cells in a Model of Peripheral Neuropathic Pain.

    Science.gov (United States)

    Jergova, Stanislava; Gajavelli, Shyam; Varghese, Mathew S; Shekane, Paul; Sagen, Jacqueline

    2016-01-01

    Chronic neuropathic pain represents a clinically challenging state with a poor response to current treatment options. Long-term management of chronic pain is often associated with the development of tolerance, addiction, and other side effects, reducing the therapeutic value of treatment. Alternative strategies based on cell therapy and gene manipulation, balancing the inhibitory and excitatory events in the spinal cord, may provide sustained pain relief in the long term. Transplantation of GABAergic cells has been successfully used to enhance inhibition and to restore physiological spinal pain processing. However, since the underlying mechanism of chronic pain development involves changes in several pain-signaling pathways, it is essential to develop an approach that targets several components of pain signaling. Recombinant cell therapy offers the possibility to deliver additional analgesic substances to the restricted area in the nervous system. The current study explores the analgesic potential of genetically modified rat embryonic GABAergic cells releasing a peptidergic NMDA receptor antagonist, Serine(1)-histogranin (SHG). Overactivation of glutamate NMDA receptors contributes to the hyperexcitability of spinal neurons observed in chronic pain models. Our approach allows us to simultaneously target spinal hyperexcitability and reduced inhibitory processes. Transplantable cells were transduced by viral vectors encoding either one or six copies of SHG cDNAs. The analgesic potential of recombinant cells after their intraspinal transplantation was evaluated in a model of peripheral nerve injury. Enhanced reduction of hypersensitivity to thermal and mechanical stimuli was observed in animals treated by recombinant cells compared to the nonrecombinant group. The recombinant peptide was detected in the spinal tissue, suggesting its successful production by transplanted cells. Our results demonstrate the feasibility of using recombinant cells releasing adjunct

  16. Bisphosphonates Inhibit Pain, Bone Loss, and Inflammation in a Rat Tibia Fracture Model of Complex Regional Pain Syndrome.

    Science.gov (United States)

    Wang, Liping; Guo, Tian-Zhi; Wei, Tzuping; Li, Wen-Wu; Shi, Xiaoyou; Clark, J David; Kingery, Wade S

    2016-10-01

    Bisphosphonates are used to prevent the bone loss and fractures associated with osteoporosis, bone metastases, multiple myeloma, and osteogenesis deformans. Distal limb fractures cause regional bone loss with cutaneous inflammation and pain in the injured limb that can develop into complex regional pain syndrome (CRPS). Clinical trials have reported that antiresorptive bisphosphonates can prevent fracture-induced bone loss, inhibit serum inflammatory cytokine levels, and alleviate CRPS pain. Previously, we observed that the inhibition of inflammatory cytokines or adaptive immune responses attenuated the development of pain behavior in a rat fracture model of CRPS, and we hypothesized that bisphosphonates could prevent pain behavior, trabecular bone loss, postfracture cutaneous cytokine upregulation, and adaptive immune responses in this CRPS model. Rats underwent tibia fracture and cast immobilization for 4 weeks and were chronically administered either subcutaneously perfused alendronate or oral zoledronate. Behavioral measurements included hindpaw von Frey allodynia, unweighting, warmth, and edema. Bone microarchitecture was measured by microcomputed tomography, and bone cellular activity was evaluated by static and dynamic histomorphometry. Spinal cord Fos immunostaining was performed, and skin cytokine (tumor necrosis factor, interleukin [IL]-1, IL-6) and nerve growth factor (NGF) levels were determined by enzyme immunoassay. Skin and sciatic nerve immunoglobulin levels were determined by enzyme immunoassay. Rats with tibia fractures developed hindpaw allodynia, unweighting, warmth, and edema, increased spinal Fos expression and trabecular bone loss in the lumbar vertebra and bilateral distal femurs as measured by microcomputed tomography, increased trabecular bone resorption and osteoclast surface with decreased bone formation rates, increased cutaneous inflammatory cytokine and NGF expression, and elevated immunocomplex deposition in skin and nerve

  17. Experimental-analytical method of technological processes modeling in education

    OpenAIRE

    Efremov German I.; Geller Julia A.

    2016-01-01

    The article considers general modeling techniques used in the study in education at different stages. The classification of different types of models and main stages of the simulation are considered. It is shown that in the course “Process of simulation” for technical areas of the Universities required the category of “Experimental-analytical simulation method”. For example, a new textbook for bachelors “Modeling of chemical-technological processes” shows that the section facilitates the comp...

  18. The Dolognawmeter: A Novel Instrument and Assay to Quantify Nociception in Rodent Models of Orofacial Pain

    Science.gov (United States)

    Dolan, John C.; Lam, David K.; Achdjian, Stacy H.; Schmidt, Brian L.

    2010-01-01

    Rodent pain models play an important role in understanding the mechanisms of nociception and have accelerated the search for new treatment approaches for pain. Creating an objective metric for orofacial nociception in these models presents significant technical obstacles. No animal assay accurately measures pain-induced orofacial dysfunction that is directly comparable to human orofacial dysfunction. We developed and validated a high throughput, objective, operant, nociceptive animal assay, and an instrument to perform the assay termed the dolognawmeter, for evaluation of conditions known to elicit orofacial pain in humans. Using the device our assay quantifies gnawing function in the mouse. We quantified a behavioral index of nociception and demonstrated blockade of nociception in three models of orofacial pain: (1) TMJ inflammation, (2) masticatory myositis, and (3) head and neck cancer. This assay will be useful in the study of nociceptive mediators involved in the development and progression of orofacial pain conditions and it will also provide a unique tool for development and assessment of new therapeutic approaches. PMID:20096303

  19. The effect of a novel core stabilization technique on managing patients with chronic low back pain: a randomized, controlled, experimenter-blinded study.

    Science.gov (United States)

    You, Joshua H; Kim, Suhn-Yeop; Oh, Duck-Won; Chon, Seung-Chul

    2014-05-01

    To identify the effect of a novel augmented core stabilization exercise technique on physical function, pain and core stability in patients with chronic low back pain. A block randomized controlled trial with two groups. A sports rehabilitation clinic. Forty patients with low back pain (20 experimental, mean (SD) age 50.35 (9.26) years and 20 control, 51.30 (7.01)), 19 men and 21 women. In the experimental group ankle dorsiflexion was used in addition to drawing in the abdominal wall; the control group involved drawing in the abdominal wall alone. Both groups received the same conventional physical therapy training three days a week for eight weeks. Physical disability instruments; Oswestry Disability Index and Roland Morris Disability Questionnaire; pain intensity assessments; visual analogue scale, Pain Disability Index, and a pain rating scale; and core stability measures, such as the active straight leg raise, were determined at pretest, posttest and two-month follow-up. After the intervention, the experimental group showed significant greater improvement at two months compared with the control group. Physical disability results included Oswestry Disability Index (P = 0.001, from 24.25 (7.08) to 13.35 (4.17)) and Roland Morris Disability Questionnaire (P = 0.001, from 15.55 (1.99) to 8.15 (1.69)), pain intensity including visual analogue scale (P = 0.001, from 6.30 (1.03) to 3.35 (0.59)), Pain Disability Index (P = 0.001, 31.25 (5.44) to 19.00 (3.58)) and pain rating scale (P = 0.001, from 72.25 (18.73) to 50.10 (15.47)), and the core stability test such as active straight leg raise (P = 0.001, from 7.40 (0.75) to 2.15 (0.49)). This study provides the clinical evidence that adding ankle dorsiflexion to drawing in the abdominal wall gave increased benefit in terms of physical disability, pain and core stability in patients with chronic low back pain.

  20. Long-term effects of interprofessional biopsychosocial rehabilitation for adults with chronic non-specific low back pain: a multicentre, quasi-experimental study.

    Directory of Open Access Journals (Sweden)

    Jana Semrau

    Full Text Available Improvement of the long-term effectiveness of multidisciplinary ortho-paedic rehabilitation (MOR in the management of chronic non-specific low back pain (CLBP remains a central issue for health care in Germany. We developed an interprofessional and interdisciplinary, biopsychosocial rehabilitation concept named "PASTOR" to promote self-management in adults with CLBP and compared its effectiveness with the current model of MOR.A multicentre quasi-experimental study with three measurement time points was implemented. 680 adults aged 18 to 65 with CLBP were assed for eligibil-ity in three inpatient rehabilitation centres in Germany. At first the effects of the MOR, with a total extent of 48 hours (control group, were assessed. Thereafter, PASTOR was implemented and evaluated in the same centres (intervention group. It consisted of six interprofessional modules, which were provided on 12 days in fixed groups, with a total extent of 48 hours. Participants were assessed with self-report measures at baseline, discharge, and 12 months for functional ability (primary outcome using the Hannover Functional Ability Questionnaire (FFbH-R and vari-ous secondary outcomes (e.g. pain, health status, physical activity, pain coping, pain-related cognitions.In total 536 participants were consecutively assigned to PASTOR (n=266 or MOR (n=270. At 12 months, complete data of 368 participants was available. The adjusted between-group difference in the FFbH-R at 12 months was 6.58 (95% CI 3.38 to 9.78 using complete data and 3.56 (95% CI 0.45 to 6.67 using available da-ta, corresponding to significant small-to-medium effect sizes of d=0.42 (p<0.001 and d=0.10 (p=0.025 in favour of PASTOR. Further improvements in secondary out-comes were also observed in favour of PASTOR.The interprofessional and interdisciplinary, biopsychosocial rehabilita-tion program PASTOR shows some improvements of the long-term effectiveness of inpatient rehabilitation in the management of adults

  1. Experimental Validation of a Dynamic Model for Lightweight Robots

    Directory of Open Access Journals (Sweden)

    Alessandro Gasparetto

    2013-03-01

    Full Text Available Nowadays, one of the main topics in robotics research is dynamic performance improvement by means of a lightening of the overall system structure. The effective motion and control of these lightweight robotic systems occurs with the use of suitable motion planning and control process. In order to do so, model-based approaches can be adopted by exploiting accurate dynamic models that take into account the inertial and elastic terms that are usually neglected in a heavy rigid link configuration. In this paper, an effective method for modelling spatial lightweight industrial robots based on an Equivalent Rigid Link System approach is considered from an experimental validation perspective. A dynamic simulator implementing the formulation is used and an experimental test-bench is set-up. Experimental tests are carried out with a benchmark L-shape mechanism.

  2. Role of sympathetic nervous system in rat model of chronic visceral pain.

    Science.gov (United States)

    Gil, D W; Wang, J; Gu, C; Donello, J E; Cabrera, S; Al-Chaer, E D

    2016-03-01

    Changes in central pain modulation have been implicated in generalized pain syndromes such as irritable bowel syndrome (IBS). We have previously demonstrated that reduced descending inhibition unveils a role of sympathoneuronal outflow in decreasing peripheral sensory thresholds, resulting in stress-induced hyperalgesia. We investigated whether sympathetic nervous system (SNS) exacerbation of pain sensation when central pain inhibition is reduced is relevant to chronic pain disorders using a rat colon irritation (CI) model of chronic visceral hypersensitivity with hallmarks of IBS. Rats were treated to a series of colorectal balloon distensions (CRD) as neonates resulting in visceral and somatic hypersensitivity and altered stool function that persists into adulthood. The visceral sensitivity was assessed by recording electromyographic (EMG) responses to CRD. Somatic sensitivity was assessed by paw withdrawal thresholds to radiant heat. The effects on the hypersensitivity of (i) inhibiting sympathoneuronal outflow with pharmacological and surgical interventions and (ii) enhancing the outflow with water avoidance stress (WAS) were tested. The alpha2-adrenergic agonist, clonidine, and the alpha1-adrenergic antagonist, prazosin, reduced the visceral hypersensitivity and WAS enhanced the pain. Chemical sympathectomy with guanethidine and surgical sympathectomy resulted in a loss of the chronic visceral hypersensitivity. The results support a role of the SNS in driving the chronic visceral and somatic hypersensitivity seen in CI rats. The findings further suggest that treatments that decrease sympathetic outflow or block activation of adrenergic receptors on sensory nerves could be beneficial in the treatment of generalized pain syndromes. © 2015 John Wiley & Sons Ltd.

  3. A review of morphine and morphine-6-glucuronide's pharmacokinetic-pharmacodynamic relationships in experimental and clinical pain

    DEFF Research Database (Denmark)

    Sverrisdóttir, Eva; Lund, Trine Meldgaard; Olesen, Anne Estrup

    2015-01-01

    Morphine is a widely used opioid for treatment of moderate to severe pain, but large interindividual variability in patient response and no clear guidance on how to optimise morphine dosage regimen complicates treatment strategy for clinicians. Population pharmacokinetic-pharmacodynamic models can...... a detailed overview of the published human population pharmacokinetic-pharmacodynamic studies for morphine analgesia in addition to basic drug disposition and pharmacological properties of morphine and its analgesic active metabolite, morphine-6-glucuronide, that may help identify future covariates....... Furthermore, based on simulations from key pharmacokinetic-pharmacodynamic models, the contribution of morphine-6-glucuronide to the analgesic response in patients with renal insufficiency was investigated. Simulations were also used to examine the impact of effect-site equilibration half-life on time course...

  4. The empathy impulse: A multinomial model of intentional and unintentional empathy for pain.

    Science.gov (United States)

    Cameron, C Daryl; Spring, Victoria L; Todd, Andrew R

    2017-04-01

    Empathy for pain is often described as automatic. Here, we used implicit measurement and multinomial modeling to formally quantify unintentional empathy for pain: empathy that occurs despite intentions to the contrary. We developed the pain identification task (PIT), a sequential priming task wherein participants judge the painfulness of target experiences while trying to avoid the influence of prime experiences. Using multinomial modeling, we distinguished 3 component processes underlying PIT performance: empathy toward target stimuli (Intentional Empathy), empathy toward prime stimuli (Unintentional Empathy), and bias to judge target stimuli as painful (Response Bias). In Experiment 1, imposing a fast (vs. slow) response deadline uniquely reduced Intentional Empathy. In Experiment 2, inducing imagine-self (vs. imagine-other) perspective-taking uniquely increased Unintentional Empathy. In Experiment 3, Intentional and Unintentional Empathy were stronger toward targets with typical (vs. atypical) pain outcomes, suggesting that outcome information matters and that effects on the PIT are not reducible to affective priming. Typicality of pain outcomes more weakly affected task performance when target stimuli were merely categorized rather than judged for painfulness, suggesting that effects on the latter are not reducible to semantic priming. In Experiment 4, Unintentional Empathy was stronger for participants who engaged in costly donation to cancer charities, but this parameter was also high for those who donated to an objectively worse but socially more popular charity, suggesting that overly high empathy may facilitate maladaptive altruism. Theoretical and practical applications of our modeling approach for understanding variation in empathy are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Experimental modeling of injectivity loss; Modelagem experimental da perda de injetividade

    Energy Technology Data Exchange (ETDEWEB)

    Bonato, Adriano Jose do Amaral Mello; Silva, Pedro Glauto de Farias e; Gomes, Vanessa Limeira Azevedo; Santos, Adriano dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Produced water reinjection, suspended particles are retained in the porous media causing formation damage and injectivity decline. In general the retention of the particles occurs near the side of injection, this fact occurs in most cases, due to the size exclusion. The modeling of filtration and the consequent formation damage is essential to the project management of water injection in oil reservoirs. Thus, mathematical models are studied to better predict the distribution of particles throughout the porous media and determine the parameters of adjustment to injectivity decline. Among these models, there is the classic model which consists in determining these parameters (coefficient of filtration and formation damage). The methodology used in modeling is given from the equations the mass conservation, kinetic particle retention, the modified Darcy equation and the function formation damage. This study aimed to improve experimental modeling, including development of software for acquisition and processing of experimental data, considering the variable number of pressure measurements along the sample. The software was developed using the Labview 2011 platform and allows the determination of relevant parameters to predict injectivity loss in water injection wells. Furthermore, based on the traditional model of filtration in porous media (including depth filtration and formation of the external plaster), the software was applied to predict injectivity loss in addition to the properties of the grout. Finally, the classical models for transporting suspensions and damage to the formation were observed. (author)

  6. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...... with the simulation prediction, showing the validity of the algorithm....

  7. Anti-nociceptive and anti-inflammatory activities of the Agastache mexicana extracts by using several experimental models in rodents.

    Science.gov (United States)

    González-Ramírez, Adriana; González-Trujano, María Eva; Pellicer, Francisco; López-Muñoz Francisco, J

    2012-08-01

    Agastache mexicana is a plant that has long been used in large demand in Mexican folk medicine to treat pain, among others affections. Nevertheless, no scientific data confirming its use have been reported. The aim of this investigation was to examine the spectrum of antinociceptive activity of A. mexicana by using different experimental models of nociception in rodents. Nociceptive activity was induced 30 min post treatment of different doses of hexane, ethyl acetate and methanol extracts from A. mexicana aerial parts. The writhing test in mice, and the formalin and plantar tests as well as the pain-induced functional impairment assay in rats (PIFIR model) were the experimental nociceptive models used. Antinociceptive response of the organic extracts was compared to that observed with the analgesic drug tramadol. A. mexicana organic extracts produced a dose-dependent and significant inhibition of the abdominal constrictions caused by 1% acetic acid injection (i.p.) in mice. A maximal antinociceptive effectiveness obtained with tramadol was also observed with the administration of hexane and ethyl acetate extracts in comparison to less effectiveness obtained with the methanol extract. At the same range of doses, A. mexicana organic extracts inhibited the behavioral responses in both phases of the formalin pain test, in which a more intense effect was observed in the inflammatory phase than in the neurogenic stage. With regard to the plantar test and PIFIR model, a significant but not dose-dependent antinociceptive response was observed at specific doses that depended on the organic extract evaluated. The antinociceptive activity of A. mexicana aerial parts depends on the intensity of the painful stimulus induced and involves different kinds of constituents. Our present results reinforce the use of this species in traditional medicine and its utility for pain treatment mainly associated with inflammation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  8. Economic evaluation in chronic pain: a systematic review and de novo flexible economic model.