Pain
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Untreated complex regional pain syndrome (CRPS) may progress from acute stages with increased hair and nail growth in the affected limb to chronic stages with atrophy of the skin, muscles and bones. The aim of this study was to investigate whether tissue hypoxia could be one mechanism responsible for this late CRPS symptoms. Nineteen patients with CRPS and two control groups (healthy control subjects, surgery patients with edema) participated in this study. ⋯ Our results indicate skin hypoxia in CRPS. Impairment of nutritive blood flow in the affected limb may be one factor contributing to atrophy and ulceration in chronic CRPS. The investigation of patients after surgery revealed that edema could not be the only reason for hypoxia.
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Cizolirtine (5-9[(N,N-dimethylaminoethoxy)phenyl]methyl0-1-methyl-1H-pyrazol citrate) is a centrally acting analgesic with a currently unknown mechanism of action, whose efficacy has been demonstrated in various models of acute and inflammatory pain in rodents. Further studies were performed in order to assess its potential antinociceptive action in a well-validated model of neuropathic pain, i.e. that produced by unilateral sciatic nerve constriction in rats. Animals were subjected to relevant behavioural tests based on mechanical (vocalization threshold to paw pressure) and thermal (struggle latency to paw immersion in a cold (10 degrees C) water bath) stimuli, 2 weeks after sciatic nerve constriction, when pain-related behaviour was fully developed. ⋯ On the other hand, cizolirtine (10 mg/kg p.o.) produced no motor deficits in animals using the rotarod test. Our study showed that cizolirtine suppressed pain-related behavioural responses to mechanical and cold stimuli in neuropathic rats, probably via an alpha(2)-adrenoceptor-dependent mechanism. These results suggest that cizolirtine may be useful for alleviating some neuropathic somatosensory disorders, in particular cold allodynia, with a reduced risk of undesirable side effects.
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Comparative Study
Functional self-efficacy and pain-related disability among older veterans with chronic pain in a primary care setting.
We examined the relationship between functional self-efficacy and pain-related disability in a sample of older veterans with chronic pain. A total of 1045 veterans aged 65 years or older who received primary care at the VA Connecticut Healthcare System in West Haven, CT, were assessed for the presence of chronic pain (i.e. pain due to a non-cancer cause for >/=3 consecutive months in the past 12 months); 303 (26%) screened positive; and 245 (81%) participated. Using a ten-item functional self-efficacy questionnaire (scale: 0-40), participants were categorized into three functional self-efficacy groups: low, score
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Comparative Study
Heat pain thresholds and cerebral event-related potentials following painful CO2 laser stimulation in chronic tension-type headache.
Current opinion concerning the pathophysiology of tension-type headache (TTH) and its related pericranial muscle tenderness proposes a primary role of central sensitization at the level of dorsalhorn/trigeminal nucleus as well as the supraspinal level. Investigation of these phenomena can be conducted using laser-evoked potentials (LEPs), which are objective and quantitative neurophysiological tools for the assessment of pain perception. In the present study we examined features of LEPs, as well as cutaneous heat-pain thresholds to laser stimulation, in relation to the tenderness of pericranial muscles in chronic TTH resulting from pericranial muscle disorder, during a pain-free phase. ⋯ The TTS scores at almost all pericranial sites were higher in TTH patients than in normal controls. The amplitude of the N2a-P2 complex elicited by stimulation of the pericranial zone was greater in TTH patients than in controls; the amplitude increase was significantly associated with the TTS score. Our findings suggest that pericranial tenderness may be a primary phenomenon that precedes headache, and is mediated by a greater pain-specific hypervigilance at the cortical level.