Pain
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Comparative Study
Effects of amitriptyline and gabapentin on bilateral hyperalgesia observed in an animal model of unilateral axotomy.
Nociceptive responses in an animal model of peripheral nerve injury were studied. The left common sciatic nerve was exposed, tightly ligated at two locations and transected between the ligatures. A bilateral decrease in the nociceptive threshold to mechanical stimulation was observed within 3 h after the operation. ⋯ Similar bilateral hyperalgesia was observed when axotomy was performed using silk thread instead of chromic gut. When this axotomy model was applied to mice, the nociceptive thresholds in both paws immediately showed a significant decrease in the same manner as in rats. The bilateral and systemic hyperalgesia observed in this axotomy model, which resembles the clinical features of chronic neuropathic pain, suggests the involvement of the central nervous system in the maintenance of the chronic pain state.
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Clinical Trial Controlled Clinical Trial
Hypersensitivity to cutaneous thermal nociceptive stimuli in irritable bowel syndrome.
Irritable bowel syndrome (IBS) is a common intestinal ailment of which the pathophysiological mechanisms are not well understood. Most IBS patients demonstrate enhanced perception, visceral hypersensitivity, in response to distension of the gut lumen but there are conflicting results about changes in somatic sensitivity. This study focused on the possible contribution of abnormal pain sensitization due to positive feedback (vicious pain cycle) that affects somatic tissues due to viscero-somatic convergence. ⋯ Sensitization of IBS patients was not limited to symptomatic dermatomes (calf) but extended evenly across the body, including to the face (no sensitization gradient from foot to face). Also, the difference between IBS and control groups did not depend on the evoked pain intensity level, i.e. the degree of sensitization of IBS patients was similar near threshold (10% on the visual analog scale) and at higher intensities. Lastly, no correlation was found between IBS subjects' pain sensitivity of any of the three test sites and their ratings of spontaneous pain.
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Randomized Controlled Trial Clinical Trial
Effect of Iyengar yoga therapy for chronic low back pain.
Low back pain is a significant public health problem and one of the most commonly reported reasons for the use of Complementary Alternative Medicine. A randomized control trial was conducted in subjects with non-specific chronic low back pain comparing Iyengar yoga therapy to an educational control group. Both programs were 16 weeks long. ⋯ Multivariate analyses of outcomes in the categories of medical, functional, psychological and behavioral factors indicated that significant differences between groups existed in functional and medical outcomes but not for the psychological or behavioral outcomes. Univariate analyses of medical and functional outcomes revealed significant reductions in pain intensity (64%), functional disability (77%) and pain medication usage (88%) in the yoga group at the post and 3-month follow-up assessments. These preliminary data indicate that the majority of self-referred persons with mild chronic low back pain will comply to and report improvement on medical and functional pain-related outcomes from Iyengar yoga therapy.
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Randomized Controlled Trial Clinical Trial
Patients initially diagnosed as 'warm' or 'cold' CRPS 1 show differences in central sensory processing some eight years after diagnosis: a quantitative sensory testing study.
We used quantitative sensory testing (QST) to gain further insight into mechanisms underlying pain in CRPS 1. Specific goals were: (1) to identify altered patterns of sensory processing some 8 years after diagnosis, (2) to document differences in sensory processing between 'warm' and 'cold' diagnostic subgroups, (3) to determine relationships between changed sensory processing and disease progression regarding pain. The study was performed on a cohort of patients (n=47) clinically diagnosed with CRPS 1 of one upper extremity approximately 8 years previously. ⋯ The latter is not the case for warm CRPS 1 patients. Both diagnostic subgroups show greater pressure hyperalgesia on the affected limb and with disease progression. QST may prove useful in the subdiagnosis of CRPS 1 and in quantifying its progression, with both applications warranting further investigation for clinical and research use.