Pain
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Plasticity in the spinal dorsal horn may underlie the development of chronic pain following peripheral nerve injury or inflammation. In this study, we examined whether chronic constriction injury of the sciatic nerve was associated with changes in the immunoreactive content of cyclic AMP response element binding protein (CREB), protein kinase A (PKA), and calcineurin Aalpha and Abeta in the spinal dorsal horn. In animals exhibiting thermal hyperalgesia as a behavioral sign of neuropathic pain 7 days after loose ligation of the sciatic nerve (chronic constriction injury), there was a significant increase in the content of phosphorylated (activated) CREB (pCREB). ⋯ In contrast, there were no differences in the content of non-phosphorylated CREB, and phosphorylated or non-phosphorylated PKA between control and sciatic ligation animals either 7 or 28 days after surgery. These data established a close association in the expression of thermal hyperalgesia with CREB activation and decreased calcineurin content in the spinal dorsal horn. The data revealed a significant but reversible shift in the manner in which spinal neurons processed sensory information following peripheral nerve injury, and lent further support to the notion that plasticity in the spinal dorsal horn may have contributed to the development of chronic pain.
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Comparative Study
Efficacy of systemic morphine suggests a fundamental difference in the mechanisms that generate bone cancer vs inflammatory pain.
Pain is the cancer related event that is most disruptive to the cancer patient's quality of life. Although bone cancer pain is one of the most severe and common of the chronic pains that accompany breast, prostate and lung cancers, relatively little is known about the mechanisms that generate and maintain this pain. Recently, we developed a mouse model of bone cancer pain and 16 days following tumor implantation into the intramedullary space of the femur, significant bone destruction and bone cancer pain-related behaviors were observed. ⋯ Humans suffering from bone cancer pain generally require significantly higher doses of morphine as compared to individuals with inflammatory pain and in the mouse model, the doses of morphine required to block bone cancer pain-related behaviors were ten times that required to block peak inflammatory pain behaviors of comparable magnitude induced by hindpaw injection of complete Freund's adjuvant (CFA) (1-3mg/kg). As these animals were treated acutely, there was not time for morphine tolerance to develop and the rightward shift in analgesic efficacy observed in bone cancer pain vs. inflammatory pain suggests a fundamental difference in the underlying mechanisms that generate bone cancer vs. inflammatory pain. These results indicate that this model may be useful in defining drug therapies that are targeted for complex bone cancer pain syndromes.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Gabapentin in neuropathic pain syndromes: a randomised, double-blind, placebo-controlled trial.
A double-blind, randomised, placebo-controlled 8-week study was conducted to evaluate the efficacy and safety of gabapentin in the treatment of neuropathic pain, using doses up to 2400 mg/day. The study used a novel design that was symptom- rather than syndrome-based; an approach that aimed to reflect the realities of clinical practice. Participants had a wide range of neuropathic pain syndromes, with at least two of the following symptoms: allodynia, burning pain, shooting pain, or hyperalgesia. ⋯ Gabapentin was well tolerated and the majority of patients completed the study (79 versus 73% for placebo). The most common adverse events were mild to moderate dizziness and somnolence, most of which were transient and occurred during the titration phase. This study shows that gabapentin reduces pain and improves some quality-of-life measures in patients with a wide range of neuropathic pain syndromes.
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Randomized Controlled Trial Comparative Study Clinical Trial
Randomized controlled trial of botulinum toxin A for chronic myogenous orofacial pain.
The purpose of this study was to determine whether botulinum toxin A (BTX-A) was efficacious for the treatment of chronic moderate to severe jaw muscle pain in females. This was a randomized double-blind, placebo-controlled crossover trial of BTX-A. Twenty five units injected into each temporalis muscle and 50 U injected into each masseter muscle using three sites per muscle with 0.2 cm(3) per site. ⋯ Statistical significance was achieved for maximum opening without pain (P=0.02) and irrespective of pain (P=0.005) with the BTX-A arm having a relative decreased opening. No statistically significant difference was observed in any outcome measures except maximum opening, which showed BTX-A patient opening less wide than placebo. The results do not support the use of BTX-A in the treatment of moderate to severe jaw muscle pain in this patient population.
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Randomized Controlled Trial Comparative Study Clinical Trial
Does acupuncture improve the orthopedic management of chronic low back pain--a randomized, blinded, controlled trial with 3 months follow up.
This prospective, randomised controlled trial, with three parallel groups, patient and observer blinded for verum and sham acupuncture and a follow up of 3 months raises the question: "Does a combination of acupuncture and conservative orthopedic treatment improve conservative orthopedic treatment in chronic low back pain (LBP). 186 in-patients of a LBP rehabilitation center with a history of LBP >or=6 weeks, VAS >or=50mm, and no pending compensation claims, were selected; for the three random group 4 weeks of treatment was applied. 174 patients met the protocol criteria and reported after treatment, 124 reported after 3 months follow up. Patients were assorted 4 strata: chronic LBP,