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Patients with migraine frequently report ocular or visual symptoms including aura, photophobia, and eye pain. Using validated instruments, our group previously reported that due to these symptoms, patients have marked reductions in visual quality of life. In chronic migraine, these reductions can be as substantial as those reported for other neuro-ophthalmic diseases such as multiple sclerosis with optic neuritis and idiopathic intracranial hypertension. Because the instruments take several different dimensions into account, we were unable to determine which ocular symptom(s) contributed to reduced visual quality of life. The purpose of this investigation was to attempt to determine which ocular symptom(s) were driving the observed reduction in visual quality of life.
Learn More >Depression is a well-recognised effect of long-term treatment with interferon-alpha (IFN-α), a widely used treatment for chronic viral hepatitis and malignancy. In addition to the emotional disturbances, high incidences of painful symptoms such as headache and joint pain have also been reported following IFN-α treatment. The endocannabinoid system plays an important role in emotional and nociceptive processing, however it is unknown whether repeated IFN-α administration induces alterations in this system. The present study investigated nociceptive responding in the IFN-α-induced mouse model of depression and associated changes in the endocannabinoid system. Furthermore, the effects of modulating peripheral endocannabinoid tone on inflammatory pain-related behaviour in the IFN-α model was examined. Repeated IFN-α administration (8,000IU/g/day) to male C57/Bl6 mice increased immobility in the forced swim test and reduced sucrose preference, without altering body weight gain or locomotor activity, confirming development of the depressive-like phenotype. There was no effect of repeated IFN-α administration on latency to respond in the hot plate test on day 4 or 7 of treatment, however, formalin-evoked nociceptive behaviour was significantly increased in IFN-α treated mice following 8 days of IFN-α administration. 2-Arachidonoyl glycerol (2-AG) levels in the periaqueductal grey (PAG) and rostroventromedial medulla (RVM), and anandamide (AEA) levels in the RVM, were significantly increased in IFN-α-, but not saline-, treated mice following formalin administration. There was no change in endocannabinoid levels in the prefrontal cortex, spinal cord or paw tissue between saline- or IFNα-treated mice in the presence or absence of formalin. Furthermore, repeated IFN-α and/or formalin administration did not alter mRNA expression of genes encoding the endocannabinoid catabolic enzymes (fatty acid amide hydrolyase or monoacylglycerol lipase) or endocannabinoid receptor targets (CB CB or PPARs) in the brain, spinal cord or paw tissue. Intra plantar administration of PF3845 (1μg/10μl) or MJN110 (1μg/10μl), inhibitors of AEA and 2-AG catabolism respectively, attenuated formalin-evoked hyperalgesia in IFN-α, but not saline-, treated mice. In summary, increasing peripheral endocannabinoid tone attenuates inflammatory hyperalgesia induced following repeated IFN-α administration. These data provide support for the endocannabinoid system in mediating and modulating heightened pain responding associated with IFNα-induced depression.
Learn More >Cannabinoid receptors type 1 (CB) and type 2 (CB) are promising targets for a number of diseases, including obesity, neuropathic pain, and multiple sclerosis, among others. Upon ligand-mediated activation of these receptors, multiple receptor conformations could be stabilized, resulting in a complex pattern of possible intracellular effects. Although numerous compounds have been developed and widely used to target cannabinoid receptors, their mode of action and signaling properties are often only poorly characterized. From a drug development point of view, unraveling the underlying complex signaling mechanism could offer the possibility to generate medicines with the desired therapeutic profile. Recently, an increased interest has emerged for the development of agonists that are signaling pathway-selective and thereby do not evoke on-target adverse effects. This phenomenon, in which specific pathways are preferred upon receptor activation by certain ligands, is also known as 'biased signaling'. For a particular group of cannabinoid receptor ligands (i.e. CB/CB agonists), namely the synthetic cannabinoid receptor agonists (SCRAs), the research on biased signaling is still in its infancy and interesting outcomes are only recently being revealed. Therefore, this review aims at providing insights into the recent knowledge about biased agonism mediated by SCRAs so far. In addition, as these outcomes are obtained using a distinct panel of functional assays, the accompanying difficulties and challenges when comparing functional outcomes are critically discussed. Finally, some guidance on the conceptualization of ideal in vitro assays for the detection of SCRA-mediated biased agonism, which is also relevant for compounds belonging to other chemical classes, is provided.
Learn More >This study aimed to identify relationships between sensory function and pain in common pain conditions (Arthritis, Complex Regional Pain Syndrome (CRPS) and Fibromyalgia Syndrome (FMS)) and healthy participants. Sensory abnormalities are known to be concomitant with some types of chronic pain but comparison across pain conditions using existing research is difficult due to methodological differences. Pragmatic Quantitative Sensory Testing (QST) methods were used.
Learn More >Research on social disparities in pain care has been mainly focused on the role of race/racism and sex/sexism. Classism in pain assessment and management practices has been much less investigated. We aimed to test the effect of patient socioeconomic status (SES; a proxy of social class) on nurses' pain assessment and management practices and whether patient SES modulated the effects of patient distress and evidence of pathology on such practices.
Learn More >Fear of pain resonates with most people, in particular in relation to dying. Despite this, there are still people dying with unrelieved pain.
Learn More >Studies to date have not comprehensively examined pain experience after total knee arthroplasty (TKA). Discrete patterns of pain in this period might be associated with pain outcomes at 6 to 12 months after TKA.
Learn More >Pain is a widely experienced symptom of inflammatory bowel disease (IBD), which has significant psychological and functional impacts on patients. Understanding the aetiology and management of chronic pain is a poorly understood area of IBD research. This qualitative study aimed to explore the experiences of individuals with IBD and pain, the pain management strategies they use and any needs for future pain management interventions.
Learn More >Exercise therapy such as motor control training (MCT) has been shown to reduce pain and disability in people with low back pain (LBP). It is unknown which patients are most likely to benefit. This longitudinal cohort study aimed to: (1) retrospectively examine records from a large cohort of patients who received MCT treatment, (2) identify potentially important predictors of response to MCT and (3) test the predictors on an independent (split) sample derived from the original cohort of patients, using one group to identify the predictors and the other to test them.
Learn More >To estimate the prevalence of having at least one or two or more chronic health conditions among US adults with self-reported migraine or severe headaches.
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