Pain
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Randomized Controlled Trial
Ultrasound guided intra-articular and rotator interval corticosteroid injections in adhesive capsulitis of the shoulder. A double blind, sham controlled randomized study.
Adhesive capsulitis (frozen shoulder) is a common cause of shoulder pain and disability. Previous studies have reported that intra-articular corticosteroid injections are of benefit compared with placebo up to 6 weeks. It has been suggested that the structures primarily involved in adhesive capsulitis are the capsule and the rotator interval. ⋯ The significant group differences were maintained at week 12 but not at week 26. Similar results were found for the secondary outcome measures (night pain, Shoulder Pain and Disability Index). Differences between the corticosteroid groups were not significant at any time.
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Combinations of analgesics with caffeine have been discussed as bearing a risk for headache chronicity. We investigated whether aspirin with caffeine (ASA+) increases headache frequency compared with aspirin alone in migraine, tension-type headache (TTH), and migraine + TTH (MigTTH). The population-based German Headache Consortium Study, which included participants aged 18 to 65 years, collected information about headache and analgesics at baseline (2003-2007, t0, response rate: 55.2%), first follow-up after 1.87 ± 0.39 years (t1, 37.2%), and second follow-up after 3.26 ± 0.60 years (t2, 38.8%). ⋯ Of 509 participants (56.0% women, 42.0 ± 11.8 years [mean ± SD]), 45.2% reported aspirin intake (41.3 ± 10.9 years, 59.6% women, headache days at t0: 2.8 ± 3.1 d/mo, t2: 3.6 ± 4.1 d/mo), 11.8% ASA+ intake (46.0 ± 9.8 years, 73.3%, t0: 4.8 ± 6.1 d/mo, t2: 5.3 ± 5.1 d/mo), and 43.0% no analgesics (41.6 ± 13.1 years, 47.5%, t0: 3.8 ± 6.2 d/mo, t2: 5.3 ± 6.6 d/mo). There was no increase in headache frequency in participants with ASA+ intake compared with aspirin (adjusted, all headache: -0.34 d/mo [95% confidence intervals: -2.50 to 1.82], migraine: -1.36 d/mo [-4.76 to 2.03], TTH: -0.57 d/mo [-4.97 to 3.84], MigTTH: 2.46 d/mo [-5.19 to 10.10]) or no analgesics (all headache: -2.24 d/mo [-4.54 to 0.07], migraine: -3.77 d/mo [-9.22 to 1.68], TTH: -4.68 d/mo [-9.62 to 0.27]; MigTTH: -3.22 d/mo [-10.16 to 3.71]). In our study, ASA+ intake did not increase headache frequency compared with aspirin or no analgesics.
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Painful peripheral neuropathy due to the antiretroviral therapy used to treat HIV is one of the most prevalent side effects occurring in at least 30% of patients living with this infection. We have evaluated the electrophysiological and behavioral effects of d4T and ddC on peripheral large and small nerve fibers in male rats treated with d4T (Sprague-Dawley, 50 mg/kg, twice within 1 week), ddC (Wistar, 50 mg/kg, 3 times per week for 3 weeks), or vehicle. The effect of the interventions was assessed using behavioral measures of mechanical sensitivity, conventional nerve conduction studies, and microneurographic single nerve C-fiber recordings. ⋯ No relationship could be established between measures of spontaneous activity in C-nociceptors and the results of the behavioral tests. Our results show that both models of antiretroviral-induced neuropathy differ in their effects on peripheral nerves. However, both groups present abnormal spontaneous activity in mechanoinsensitive C-nociceptors that can be used as a model for pharmacological intervention.
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Mechanical allodynia, a cardinal symptom of persistent pain, is associated with the unmasking of usually blocked local circuits within the superficial spinal or medullary dorsal horn (MDH) through which low-threshold mechanical inputs can gain access to the lamina I nociceptive output neurons. Specific interneurons located within inner lamina II (IIi) and expressing the gamma isoform of protein kinase C (PKCγ⁺) have been shown to be key elements for such circuits. However, their morphologic and electrophysiologic features are still unknown. ⋯ In addition, at least 2 morphologically and functionally different subpopulations of PKCγ⁺ interneurons can be identified: central and radial PKCγ⁺ interneurons. The former exhibit a lower membrane input resistance, rheobase and, thus, action potential threshold, and less PKCγ⁺ immunoreactivity than the latter. These 2 subpopulations might thus differently contribute to the gating of dorsally directed circuits within the MDH underlying mechanical allodynia.