Pain
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Multicenter Study
Determining behavioural and physiological responses to pain in infants at risk for neurological impairment.
Multiple researchers have validated indicators and measures of infant pain. However, infants at risk for neurologic impairment (NI) have been under studied. Therefore, whether their pain responses are similar to those of other infants is unknown. ⋯ A significant Phase effect for low/high frequency Heart Rate Variability (HRV) ratio (F(2,216)=4.97, p=0.008) was found with the greatest decrease in Cohort A. Significant Cohort by Phase interactions existed for low and high frequency HRV. All infants responded to the most painful phase of the heel lance; however, infants at moderate and highest risk for NI exhibited decreased responses in some indicators.
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The experience of pain has been documented in small studies of individuals with multiple sclerosis (MS). The present study examines the prevalence of persistent pain and uncomfortable sensations among participants in the large North American Research Committee on MS (NARCOMS) Patient Registry. Registrants (10,176) responded to a questionnaire on pain and 7579 reported experiencing some level of pain during the month prior to the survey. ⋯ About one-third of the patients with moderate pain and 18% of those with severe pain reported no consultations for their pain. The effects of pain severity were fully evident in the respondents' daily life, their work, mood, recreational activities and enjoyment of life. Our results indicate that the high prevalence of MS-related severe pain, low satisfaction with management of intense pain, and the perceived interference with quality of life indicators necessitate greater attention by healthcare providers to the management of pain and uncomfortable sensations in the MS population.
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The analgesic effects of local administration of opioid agonists into peripheral tissues in alleviating pain have been well documented in both clinical and preclinical studies, although few studies have examined their effects in neuropathic pain. In this study, we investigated the anti-allodynic effects of peripherally acting delta opioid receptor (DOR) agonists in a rat model of neuropathic pain. Peripheral nerve injury (PNI) produced a time-dependent decrease in mechanical withdrawal thresholds that was attenuated by local administration into the hind paw of either morphine or the DOR agonist deltorphin II. ⋯ Results obtained from immunohistochemical studies confirmed up-regulation in small and large DRG neurons in neuropathic compared to sham animals. Additionally, there was an increase in DOR protein within the ipsilateral sciatic nerve of neuropathic animals compared to sham and contralateral neuropathic conditions indicating the occurrence of receptor trafficking to the site of injury. Taken together, our findings suggest that functional peripheral DORs are present in sensory neurons following PNI and validate the development of selective DOR agonists for alleviating neuropathic pain.