Pain
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Comparative Study
Developmental changes in pain expression in premature, full-term, two- and four-month-old infants.
The purpose of this study was to examine the behavioural responses of infants to pain stimuli across different developmental ages. Eighty infants were included in this cross-sectional design. Four subsamples of 20 infants each included: (1) premature infants between 32 and 34 weeks gestational age undergoing heel-stick procedure; (2) full-term infants receiving intramuscular vitamin K injection; (3) 2-month-old infants receiving subcutaneous injection for immunisation against DPT; and (4) 4-month-old infants receiving subcutaneous injection for immunisation against DPT. ⋯ The results imply that the premature infant has the basis for communicating pain via facial actions but that these are not well developed. The full-term newborn is better equipped to interact with his caretakers and express his distress through specific facial actions. The cries of the premature infant, however, have more of the characteristics that are arousing to the listener which serve to alert the caregiver of the state of distress from pain.
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Pilot studies and a literature review suggested that fear-avoidance beliefs about physical activity and work might form specific cognitions intervening between low back pain and disability. A Fear-Avoidance Beliefs Questionnaire (FABQ) was developed, based on theories of fear and avoidance behaviour and focussed specifically on patients' beliefs about how physical activity and work affected their low back pain. Test-retest reproducibility in 26 patients was high. ⋯ These results confirm the importance of fear-avoidance beliefs and demonstrate that specific fear-avoidance beliefs about work are strongly related to work loss due to low back pain. These findings are incorporated into a biopsychosocial model of the cognitive, affective and behavioural influences in low back pain and disability. It is recommended that fear-avoidance beliefs should be considered in the medical management of low back pain and disability.
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Thirty-five cancer patients, treated with chronic epidural morphine, were assayed for plasma and cerebrospinal fluid (CSF) minimum steady-state concentrations (Css min) of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by high performance liquid chromatography (HPLC). A linear dose-concentration relationship was found for the 3 substances in plasma and for morphine and M3G in CSF. The mean +/- S. ⋯ CSF M6G concentrations were low and did not contribute to any detectable analgesia. We conclude that after epidural administration of morphine, the M3G and M6G metabolites in CSF are low compared to unchanged morphine and seem to have little influence on analgesia. However, the fact that a significant passage of the glucuronide metabolites occurs to the CSF may indicate a role in morphine analgesia after other routes of administration.
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Methadone is a synthetic opiate receptor agonist that has been available for more than 40 years. Although its main use has been in the maintenance treatment of opioid addicts, it has excellent analgesic effects and low cost. ⋯ Methadone should be titrated carefully and individualized doses and intervals should be determined for each patient. Future research should attempt to determine the equi-analgesic dose for chronic use, its effectiveness and tolerance when used in high doses, and its absorption and tolerance using alternative routes, e.g., rectal and subcutaneous.
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Adrenal medullary transplants in the spinal subarachnoid space, by providing a continual source of opioid peptides and catecholamines, offer a potentially important adjunct in the management of chronic pain. While previous studies have shown that this approach is effective against high-intensity phasic stimuli, adrenal medullary implants need to be evaluated against long-term and abnormal pain syndromes before transplantation can be used for human chronic pain. Using a recently developed model of painful peripheral neuropathy, the effects of adrenal medullary chromaffin cells transplanted into the subarachnoid space was evaluated. ⋯ Touch-evoked allodynia was only slightly reduced by adrenal medullary transplants. In addition, indicators of spontaneous pain appeared reduced in animals with adrenal medullary transplants. These findings indicate that adrenal medullary transplants may be effective in reducing neuropathic pain.