Pain
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Randomized Controlled Trial
TRPV1 antagonistic analgesic effect: a randomized study of AZD1386 in pain after third molar extraction.
The effects of a TRPV1 antagonist (AZD1386) were investigated in patients with acute pain. After removal of a mandibular third molar and at request of analgesia 103 patients randomly received 95 mg AZD1386 (n = 40), placebo (n = 40) or 500 mg naproxen (n = 23) in a double-blind manner. Plasma samples were drawn, and pain intensity and body temperature were measured during 8 h after drug administration. ⋯ Adverse events were similar to placebo with the exception of 2 patients reporting chills. The highest individual body temperature after AZD1386 was 38.1°C, recorded in 2 patients. In summary, AZD1386 was well tolerated with a rapid analgesia that was short lasting despite sustained plasma concentration.
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Functional magnetic resonance imaging (fMRI) is a technique that uses blood oxygen-level-dependent (BOLD) signals to elucidate discrete areas of neuronal activity. Despite the significant number of fMRI human brain studies, few researchers have applied fMRI technology to investigating neuronal activity within the human spinal cord. Our study goals were to demonstrate that fMRI could reveal the following: (i) appropriate somatotopic activations in response to noxious stimuli in the deep and superficial dorsal horn of the human cervical spinal cord, and (ii) lateralization of fMRI activations in response to noxious stimulation in the right and left upper extremity. ⋯ During nociceptive stimulation of all 4 sites (left deltoid, right deltoid, left thenar eminence and right thenar eminence), we found ipsilateral dorsal horn activation. Stimulation of the deltoid activated C5, whereas stimulation of the thenar eminence activated C6. Our study contributes to creating an objective analysis of pain transmission; other investigators can use these results to further study central nervous system changes that occur in patients with acute and chronic pain.
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Perception of emotional stimuli alters the perception of pain. Although facial expressions are powerful emotional cues - the expression of pain especially plays a crucial role for the experience and communication of pain - research on their influence on pain perception is scarce. In addition, the opposite effect of pain on the processing of emotion has been elucidated even less. ⋯ Most important, painful thermal stimuli increased the arousal of simultaneously presented pain expressions, and in turn, pain expressions resulted in higher pain ratings compared to all other facial expressions. These findings demonstrate that the modulation of pain and emotion is bidirectional with pain faces being mostly prone to having mutual influences, and support the view of interconnections between pain and emotion. Furthermore, the special relevance of pain faces for the processing of pain was demonstrated.
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Musculoskeletal disorders constitute major public health problems. Few studies have, however, examined risk of disability pension among persons sickness absent due to musculoskeletal diagnoses. Thus, we constructed a prospective nationwide population-based cohort study based on Swedish registers, consisting of all 4,687,756 individuals living in Sweden December 31, 2004/2005, aged 20-64 years, who were not on disability or old-age pension. ⋯ Similar associations were observed among both women and men sickness absent due to all 3 musculoskeletal diagnostic categories. Moreover, increased risks of disability pension because of cancer, mental, circulatory and musculoskeletal diagnoses were observed among individuals sickness absent because of any musculoskeletal diagnostic category (disability pension due to musculoskeletal diagnoses, adjusted model, category 2 diagnoses, IRR = 50.66, 95% CI = 49.06-52.32). In conclusion, this nationwide cohort study reveals strongly increased risks of all-cause and diagnosis-specific disability pension among those sickness absent due to musculoskeletal diagnoses.
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Although previous research has examined the relationships between caregiver proximal soothing and infant pain, there is a paucity of work taking infant age into account, despite the steep developmental trajectory that occurs across the infancy period. Moreover, no studies have differentially examined the relationships between caregiver proximal soothing and initial infant pain reactivity and pain regulation. This study examined how much variance in pain reactivity and pain regulation was accounted for by caregiver proximal soothing at 4 routine immunizations (2, 4, 6, and 12 months) across the first year of life, controlling for preneedle distress. ⋯ Preneedle distress and pain reactivity accounted for the largest amount of variance in pain regulation, with this increasing after 2 months. It was concluded that within each immunization appointment across the first year of life, earlier infant pain behaviour is a stronger predictor of subsequent infant pain behaviour than caregiver proximal soothing. Given the longer-term benefits that have been demonstrated for proximal soothing during distressing contexts, caregivers are still encouraged to use proximal soothing during infant immunizations.