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- 2019
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Journal article (peer-reviewed)
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| 2. |
- Western, Benedikte, et al.
(author)
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Dropout from exercise trials among cancer survivors—An individual patient data meta-analysis from the POLARIS study
- 2024
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In: Scandinavian Journal of Medicine and Science in Sports. - Chichester, West Sussex : Wiley-Blackwell Publishing Inc.. - 0905-7188 .- 1600-0838. ; 34:2, s. 1-10
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Journal article (peer-reviewed)abstract
- Introduction: The number of randomized controlled trials (RCTs) investigating the effects of exercise among cancer survivors has increased in recent years; however, participants dropping out of the trials are rarely described. The objective of the present study was to assess which combinations of participant and exercise program characteristics were associated with dropout from the exercise arms of RCTs among cancer survivors. Methods: This study used data collected in the Predicting OptimaL cAncer RehabIlitation and Supportive care (POLARIS) study, an international database of RCTs investigating the effects of exercise among cancer survivors. Thirty-four exercise trials, with a total of 2467 patients without metastatic disease randomized to an exercise arm were included. Harmonized studies included a pre and a posttest, and participants were classified as dropouts when missing all assessments at the post-intervention test. Subgroups were identified with a conditional inference tree. Results: Overall, 9.6% of the participants dropped out. Five subgroups were identified in the conditional inference tree based on four significant associations with dropout. Most dropout was observed for participants with BMI >28.4 kg/m2, performing supervised resistance or unsupervised mixed exercise (19.8% dropout) or had low-medium education and performed aerobic or supervised mixed exercise (13.5%). The lowest dropout was found for participants with BMI >28.4 kg/m2 and high education performing aerobic or supervised mixed exercise (5.1%), and participants with BMI ≤28.4 kg/m2 exercising during (5.2%) or post (9.5%) treatment. Conclusions: There are several systematic differences between cancer survivors completing and dropping out from exercise trials, possibly affecting the external validity of exercise effects. © 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.
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| 3. |
- Schmelz, M., et al.
(author)
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Active "itch fibers" in chronic pruritus
- 2003
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In: Neurology. - : Lippincott Williams & Wilkins. - 0028-3878 .- 1526-632X. ; 61:4, s. 564-566
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Journal article (peer-reviewed)abstract
- An itch-specific neuronal pathway was recently discovered in healthy humans and animals. Here the authors report that activity in this specific pathway coincides with itch under pathophysiologic conditions in a patient with chronic pruritus. Microneurographic recordings from the symptomatic area revealed spontaneous activity in six single C-fiber afferents that had the characteristic features of "itch fibers." Itch may be caused by activity in a specific subpopulation of C-fiber afferents.
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| 4. |
- Schmelz, M., et al.
(author)
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Chemical response pattern of different classes of C-nociceptors to pruritogens and algogens
- 2003
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In: Journal of Neurophysiology. - Washington : The American Physiological Society. - 0022-3077 .- 1522-1598. ; 89:5, s. 2441-2448
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Journal article (peer-reviewed)abstract
- Vasoneuroactive substances were applied through intradermal microdialysis membranes and characterized as itch- or pain-inducing in psychophysical experiments. Histamine always provoked itching and rarely pain, capsaicin always pain but never itching. Prostaglandin E[2] (PGE[2]) led preferentially to moderate itching. Serotonin, acetylcholine, and bradykinin induced pain more often than itching. Subsequently the same substances were used in microneurography experiments to characterize the sensitivity profile of human cutaneous C-nociceptors. The responses of 89 mechanoresponsive (CMH, polymodal nociceptors), 52 mechanoinsensitive, histamine-negative (CMi[H][i][s][-]), and 24 mechanoinsensitive, histamine-positive (CMi[H][i][s][+]) units were compared. CMi[H][i][s][+] units were most responsive to histamine and to PGE[2] and less to serotonin, ACh, bradykinin, and capsaicin. CMH units (polymodal nociceptors) and CMi[H][i][s] units showed significantly weaker responses to histamine, PGE[2], and acetylcholine. Capsaicin and bradykinin responses were not significantly different in the two classes of mechano-insensitive units. We conclude that CMi[H][i][s][+]units are "selective," but not "specific" for pruritogenic substances and that the pruritic potency of a mediator increases with its ability to activate CMi[H][i][s][+] units but decreases with activation of CMH and CMi[H][i][s] units.
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| 5. |
- Weidner, Christian, et al.
(author)
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Neural Signal Processing : The Underestimated Contribution of Peripheral Human C-Fibers
- 2002
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In: Journal of Neuroscience. - : The Society for Neuroscience. - 1529-2401. ; 22:15, s. 6704-6712, s. 6704-
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Journal article (peer-reviewed)abstract
- The microneurography technique was used to analyze use-dependent frequency modulation of action potential (AP) trains in human nociceptive peripheral nerves. Fifty-one single C-afferent units (31 mechano-responsive, 20 mechano-insensitive) were recorded from cutaneous fascicles of the peroneal nerve in awake human subjects. Trains of two and four suprathreshold electrical stimuli at interstimulus intervals of 20 and 50 msec were applied to the receptive fields of single identified nociceptive units at varying repetition rates. The output frequency (interspike interval) recorded at knee level was compared with the input frequency (interstimulus interval) at different levels of accumulated neural accommodation.At low levels of use-dependent accommodation (measured as conduction velocity slowing of the first action potential in a train), intervals between spikes increased during conduction along the nerve. At increasing levels of neural accommodation, intervals decreased because of a relative supernormal period (SNP) and asymptotically approached the minimum "entrainment" interval of the nerve fiber (11 ± 1.4 msec) corresponding to a maximum instantaneous discharge frequency (up to 190 Hz).For neural coding, this pattern of frequency decrease at low activity levels and frequency increase at high levels serves as a mechanism of peripheral contrast enhancement. The entrainment interval is a good minimum estimate for the duration of the refractory period of human C-fibers.At a given degree of neural accommodation, all afferent C-units exhibit a uniform pattern of aftereffects, independent of fiber class. The receptive class of a fiber only determines its susceptibility to accommodate. Thus, the time course of aftereffects and existence or absence of an SNP is fully explained by the amount of preexisting accommodation.
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| 6. |
- Örstavik, K., et al.
(author)
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Abnormal function of C-fibers in patients with diabetic neuropathy
- 2006
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In: Journal of Neuroscience. - Washington DC, USA : The Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 26:44, s. 11287-11294
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Journal article (peer-reviewed)abstract
- The mechanisms underlying the development of painful and nonpainful neuropathy associated with diabetes mellitus are unclear. We have obtained microneurographic recordings from unmyelinated fibers in eight patients with diabetes mellitus, five with painful neuropathy, and three with neuropathy without pain. All eight patients had large-fiber neuropathy, and seven patients had pathological thermal thresholds in their feet, indicating the involvement of small-caliber nerve fibers. A total of 163 C-fibers were recorded at knee level from the common peroneal nerve in the patients (36-67 years old), and these were compared with 77 C-fibers from healthy controls (41-64 years old). The ratio of mechano-responsive to mechano-insensitive nociceptors was similar to 2:1 in the healthy controls, whereas in the patients, it was 1:2. In patients, a fairly large percentage of characterized fibers (12.5% in nonpainful and 18.9% in painful neuropathy) resembled mechano-responsive nociceptors that had lost their mechanical and heat responsiveness. Such fibers were rarely encountered in age-matched controls (3.2%). Afferent fibers with spontaneous activity or mechanical sensitization were found in both patient groups. We conclude that small-fiber neuropathy in diabetes affects receptive properties of nociceptors that leads to an impairment of mechano-responsive nociceptors.
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