Pain
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Children born very prematurely (< or =32 weeks) often exhibit visual-perceptual difficulties at school-age, even in the absence of major neurological impairment. The alterations in functional brain activity that give rise to such problems, as well as the relationship between adverse neonatal experience and neurodevelopment, remain poorly understood. Repeated procedural pain-related stress during neonatal intensive care has been proposed to contribute to altered neurocognitive development in these children. ⋯ We demonstrated alterations in the spectral structure of spontaneous cortical oscillatory activity in ELGA children at school-age. Cumulative neonatal pain-related stress was associated with changes in background cortical rhythmicity in these children, and these alterations in spontaneous brain oscillations were negatively correlated with visual-perceptual abilities at school-age, and were not driven by potentially confounding neonatal variables. These findings provide the first evidence linking neonatal pain-related stress, the development of functional brain activity, and school-age cognitive outcome in these vulnerable children.
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Growing evidence suggests that leukocyte extravasation is initiated by the interaction of selectins with their ligands; as well as an essential role for P-selectin in the initial recruitment of inflammatory cells to sites of inflammation. In this study, P-selectin-deficient (P-sel-/-) mice were used to test the hypothesis that lack of P-selectin would attenuate the recruitment of inflammatory cells to the site of inflammation, thereby modulating pain in a murine chronic neuropathic pain model. Nociceptive sensitization and the microenvironment of the peripheral injury site were studied in wild-type (P-sel+/+) and P-selectin-deficient (P-sel-/-) mice after partial sciatic nerve ligation (PSNL). ⋯ In addition, endogenous opioid peptides mRNA was significantly lower in P-sel-/- mice compared with P-sel +/+ mice. The current results demonstrated that the absence of P-selectin in mice leads to an altered microenvironment that attenuated behavioral hypersensitivity. The specific role of P-selectin could have been a result of decreased neutrophils, as well as the accumulation of macrophages at the site of injury, which may subsequently modulate the inflammatory cytokine expression and impact behavioral hypersensitivity within the injured nerve.
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Randomized Controlled Trial
Lack of endogenous opioid release during sustained visceral pain: A [(11)C]carfentanil PET study.
Opioidergic neurotransmission in the central nervous system is involved in somatic pain, but its role in visceral pain remains unknown. We aimed to quantify endogenous opioid release in the brain during sustained painful gastric distension. Therefore, 2 dynamic [11C]carfentanil positron emission tomography scans were performed in 20 healthy subjects during 2 conditions: sustained (20 minutes) painful proximal gastric balloon distension at predetermined individual discomfort threshold (PAIN) and no distension (NO PAIN), in counterbalanced order. ⋯ No difference in endogenous opioid release was demonstrated in any of the volumes of interest. Thus, contrary to its somatic counterpart, no opioid release is detected in the brain during sustained visceral pain, despite similar pain intensities. Endogenous opioids may play a less important role in visceral compared to somatic pain.
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Pain is known to play an important role in the pathway to becoming work disabled, in particular for award of disability pensions (DP) due to musculoskeletal diagnoses (MSD). This prospective cohort study investigated MSD-related pain stability and/or changes as predictors for DP during a 23-year follow-up. Additionally confounding factors were examined to elucidate whether familial effects (including genetics and family background) or socioeconomic status, other pain, or use of medication would affect the associations between pain and DP. ⋯ Musculoskeletal pain impairing work ability both measured at 1 time point and 6 years apart, and either 1 pain location or multiple locations, predicted increased risk for DP due to MSD, OA, and LBD. The associations were independent of familial confounding factors and of several influential background factors, including headache; migraine; use of analgesics, hypnotics, or tranquillizers; life satisfaction; and education and marital status. This study concluded that musculoskeletal pain impairing work ability is an early and direct predictor for DP due to MSD, OA, and LBD.
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Randomized Controlled Trial
Disturbed sensory perception of changes in thermoalgesic stimuli in patients with small fiber neuropathies.
The assessment of functional deficits in small fibre neuropathies (SFN) requires using ancillary tests other than conventional neurophysiological techniques. One of the tests with most widespread use is thermal threshold determination, as part of quantitative sensory testing. Thermal thresholds typically reflect one point in the whole subjective experience elicited by a thermal stimulus. ⋯ Abnormalities seen in patients in comparison to healthy subjects were: (1) delayed perception of temperature changes, both at onset and at reversal, (2) longer duration of pain perception at peak temperature, and (3) absence of an overshoot sensation after reversal, ie, a transient perception of the opposite sensation before the temperature reached again baseline. The use of DTT increases the yield of thermal testing for clinical and physiological studies. It adds information that can be discriminant between healthy subjects and SFN patients and shows physiological details about the process of activation and inactivation of temperature receptors that may be abnormal in SFN.