Pain
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Results from laboratory and naturalistic studies have demonstrated decreased subjective pain ratings in hypertensives and individuals at risk for hypertension. Based on previous evidence that the nociceptive withdrawal reflex may provide an objective index of pain threshold in humans, the present study examined the intensity of sural nerve stimulation required to elicit nociceptive withdrawal in offspring of hypertensives and normotensives. Participants included 60 men and 56 women who were normotensive, 18-23 years of age, and predominately Caucasian. ⋯ Second, offspring of hypertensives endured significantly more intense stimulation before reporting pain. Third, both parental history of hypertension and resting systolic blood pressure were significant independent predictors of stimulation intensity at nociceptive withdrawal reflex and subjective pain thresholds. These results confirm and extend previous observations of an association between risk for hypertension and hypoalgesia, and suggest that hypoalgesia should be examined as a potential predictor of progressive blood pressure increases in individuals at risk for hypertension.
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Our previous studies in the Sprague-Dawley rat showed that the intrinsic antinociceptive effects of oxycodone are naloxone reversible in a manner analogous to morphine but that in contrast to morphine, oxycodone's antinociceptive effects have a rapid onset of maximum effect (approximately 5-7 min compared to 30-45 min for morphine), comprise one antinociceptive phase (compared to two phases) and are of relatively short duration (approximately 90 min compared to approximately 180 min). In the present study, administration of a range of selective opioid receptor antagonists has shown that the intrinsic antinociceptive effects of oxycodone (171 nmol) are not attenuated by i.c.v. administration of (i) naloxonazine, a mu1-selective opioid receptor antagonist, or (ii) naltrindole, a delta-selective opioid receptor antagonist, in doses that completely attenuated the intrinsic antinociceptive effects of equipotent doses of the respective mu- and delta-opioid agonists, morphine and enkephalin-[D-Pen(2,5)] (DPDPE). ⋯ Importantly, the antinociceptive effects of oxycodone (171 nmol i.c.v.) were markedly attenuated by the prior i.c.v. administration of the selective kappa-opioid receptor antagonist, norbinaltorphimine (nor-BNI), in a dose (0.3 nmol) that did not attenuate the antinociceptive effects of an equipotent dose of i.c.v. morphine (78 nmol). Taken together, these data strongly suggest that the intrinsic antinociceptive effects of oxycodone are mediated by kappa-opioid receptors, in contrast to morphine which interacts primarily with mu-opioid receptors.
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Randomized Controlled Trial Comparative Study Clinical Trial
The efficacy of radiofrequency lesioning of the cervical spinal dorsal root ganglion in a double blinded randomized study: no difference between 40 degrees C and 67 degrees C treatments.
The efficacy of radiofrequency lesion treatment of the cervical dorsal root ganglion (RF-DRG) in cervicobrachialgia was investigated in 61 patients by a randomized prospective double blinded study. Before lesion treatment the putative pain provoking spinal root was identified by diagnostic blocks with a local anesthetic agent. One group of patients (n = 32, group I) was treated with a radiofrequency lesion of 67 degrees C and in a control group (n = 29, group II) a temperature of 40 degrees C was applied. ⋯ A VAS reduction of 2 or more occurred in group I in 15/31 (47%) and in group II in 15/29 (51%) of patients. This study suggests that treatment with 40 degrees C radiofrequency application of the dorsal root ganglion is equally effective as treatment at 67 degrees C. Further appraisal of this treatment is required.
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
Opiate and H1 antagonist effects on histamine induced pruritus and alloknesis.
Itching is a well known side-effect of opiate therapy. To gain insight into the possible contribution of opiate receptors to itching we compared the antipruritic effect of naltrexone (Nemexin), an opiate antagonist, to an H1-receptor antagonist and to placebo. In a double blind cross-over study on 15 healthy volunteers, 25 mg naltrexone or placebo was orally given 60 min prior to a histamine stimulus. ⋯ Both naltrexone and cetirizine significantly diminished histamine induced itching. In contrast to placebo and cetirizine, naltrexone abolished alloknesis completely in four of 15 volunteers and in the others alloknesis was greatly reduced after naltrexone. Since vascular reactions to histamine are of peripheral origin, whereas alloknesis depends on central nervous mechanisms, our findings suggest a pronounced centrally mediated action of naltrexone on histamine induced pruritus.
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Comparative Study Clinical Trial Controlled Clinical Trial
Pain coping strategies that predict patients' and spouses' ratings of patients' self-efficacy.
This study examined the relationship of pain coping strategies to osteoarthritis patients' ratings of self-efficacy and to spouses' ratings of the patients' self-efficacy. Subjects, 130 individuals having osteoarthritis of the knees and persistent knee pain, completed a pain coping strategies measure (the Coping Strategies Questionnaire), a measure of self-efficacy (the Arthritis Self-Efficacy Scale), and a measure of pain (the McGill Pain Questionnaire). Two sets of regression analyses were conducted, one examining the degree to which pain coping strategies predicted patients' self-efficacy ratings, and the other examining the degree to which coping strategies predicted spouses' ratings of the patients' self-efficacy. ⋯ The findings regarding coping strategies were particularly interesting in that they were obtained even after controlling for pain intensity and demographic variables. The pain coping strategies identified are potentially important targets for cognitive-behavioral assessment and treatment efforts. Interventions designed to increase the use of adaptive pain coping strategies and decrease the use of maladaptive pain coping strategies could enhance self-efficacy, reduce pain, and improve the physical and psychological functioning of individuals having osteoarthritis.