Pain
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Various mechanisms at peripheral, spinal and/or supraspinal levels may underlie neuropathic pain. The nervous system's capacity for long-term reorganisation and chronic pain may result from abnormalities in RVM facilitatory On cells. Hence, via brainstem injections of the toxic conjugate dermorphin-saporin, which specifically lesions facilitatory cells expressing the mu-opioid receptor (MOR), we sought to determine the influence of these cells in normal and spinal nerve-ligated (SNL) rats. ⋯ During the early stages of nerve injury, or following medullary MOR cell ablation, PGB is ineffective at inhibiting spinal neuronal responses possibly due to quiescent spinal 5HT(3) receptors. This can however be overcome, and PGB's efficacy restored, by pharmacologically mimicking the descending drive at the spinal level with a 5HT(3) receptor agonist. Since RVM facilitatory neurones are integral to a spino-bulbo-spinal loop that reaches brain areas co-ordinating the sensory and affective components of pain, we propose that activity therein may influence painful outcome following nerve injury, and responsiveness to treatment.
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Multicenter Study
Severity of acute pain after childbirth, but not type of delivery, predicts persistent pain and postpartum depression.
Cesarean delivery rates continue to increase, and surgery is associated with chronic pain, often co-existing with depression. Also, acute pain in the days after surgery is a strong predictor of chronic pain. Here we tested if mode of delivery or acute pain played a role in persistent pain and depression after childbirth. ⋯ Women with severe acute postpartum pain had a 2.5-fold increased risk of persistent pain and a 3.0-fold increased risk of postpartum depression compared to those with mild postpartum pain. In summary, cesarean delivery does not increase the risk of persistent pain and postpartum depression. In contrast, the severity of the acute pain response to childbirth predicts persistent morbidity, suggesting the need to more carefully address pain treatment in the days following childbirth.
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Comparisons of measurement characteristics were made for three types of electronic pain scales: (a) visual analogue scale (VAS), (b) VAS combined with an electronic number box (VAS-N; 0-100), and (c) electronic number box scale (NUM). The three scales were capable of discriminating pain sensations from very small (0.5 degrees C) temperature steps in 13 healthy males, 26 healthy females, and 16 female fibromyalgia (FM) patients. All scales provided monotonic functions when used by subjects to rate pain from 5s nociceptive temperatures (45-49 degrees C), thereby demonstrating the generality of these results across different demographic groups. ⋯ However, in comparison to male subjects, healthy females gave higher NUM but not VAS or VAS-N ratings to the range of nociceptive presented temperatures. We interpret this difference as a selective scaling bias of female subjects for NUM. Finally, all three groups (total of 55 subjects) found the scales easy to use after brief instructions, though subjects strongly preferred the use of VAS-N or VAS in comparison to NUM scale.
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Intrusive pain is likely to have a serious impact on older people with limited ability to respond to additional stressors. Frailty is conceptualised as a functional and biological pattern of decline accumulating across multiple physiological systems, resulting in a decreased capacity to respond to additional stressors. We explored the relationship between intrusive pain, frailty and comorbid burden in 1705 community-dwelling men aged 70 or more who participated in the baseline phase of the CHAMP study, a large epidemiological study of healthy ageing based in Sydney, Australia. 9.4% of men in the study were frail (according to the commonly-used Cardiovascular Health Study frailty criteria). ⋯ Additionally, men with the highest overall health burden (frail plus high comorbid burden) were most likely to report intrusive pain (adjusted odds ratio 3.0 (95% CI 1.6-5.5), p=0.0004). These findings provide support for the concept that intrusive pain is an important challenge for older men with limited capacity to respond to additional physical stressors. To our knowledge, this is the first study to explore specifically the relationship between pain and frailty.
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Pain assessment is subject to bias due to characteristics of the individual in pain and of the observing person. Few research studies have examined pain assessment biases in an experimental setting. This study employs innovative virtual human technology to achieve greater experimental control. ⋯ Nomothetic analyses showed that higher pain expression VH and female VH were viewed as having higher pain intensity, higher pain unpleasantness, greater negative mood, worse coping, and a greater need to seek medical treatment than lower pain expression VH and male VH, respectively. Older VH were viewed as having worse coping and a greater need to seek medical treatment than younger VH. This innovative paradigm involving VH technology and a lens model design was shown to be highly effective and could serve as a model for future studies investigating pain-related decision making in healthcare providers.