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1.  Somatosensory Abnormalities for Painful and Innocuous Stimuli at the Back and at a Site Distinct from the Region of Pain in Chronic Back Pain Patients 
PLoS ONE  2013;8(3):e58885.
Chronic low back pain (CLBP) was shown to be associated with pathophysiological changes at several levels of the sensorimotor system. Changes in sensory thresholds have been reported but complete profiles of Quantitative Sensory Testing (QST) were only rarely obtained in CLBP patients. The aim of the present study was to investigate comprehensive QST profiles in CLBP at the painful site (back) and at a site distinct from their painful region (hand) and to compare these data with similar data in healthy controls. We found increased detection thresholds in CLBP patients compared to healthy controls for all innocuous stimuli at the back and extraterritorial to the painful region at the hand. Additionally, CLBP patients showed decreased pain thresholds at both sites. Importantly, there was no interaction between the investigated site and group, i.e. thresholds were changed both at the affected body site and for the site distinct from the painful region (hand). Our results demonstrate severe, widespread changes in somatosensory sensitivity in CLBP patients. These widespread changes point to alterations at higher levels of the neuraxis or/and to a vulnerability to nociceptive plasticity in CLBP patients.
PMCID: PMC3598908  PMID: 23554950
2.  Enhanced sensitivity to punctate painful stimuli in female patients with chronic low back pain 
BMC Neurology  2012;12:98.
Chronic low back pain (CLBP) has been shown to be associated with various pathophysiological changes at several level of the sensorimotor system, pointing to a general hypersensitivity in CLBP patients. The aim of the present study was to investigate signs of generalized mechanical pain hypersensitivity in CLBP patients on the hand and on the painful site of the back.
Pinprick stimulation according to a validated standardized quantitative sensory testing protocol was used in 14 female CLBP patients and 14 healthy controls (HC) matched for sex and age. Stimulus response functions to pinprick stimulation on the skin were examined at the affected back and reference sites (hand palmar and hand dorsum). Data from CLBP patients were compared with HC and with reference data from the German Research Network on Neuropathic Pain.
We found significant differences in the stimulus response functions between CLBP patients and HC. Pain ratings to the pinpricks were increased for low and moderate pinprick stimuli in CLBP patients. Importantly, this kind of specific pinprick hyperalgesia was found not only for the affected body site (back), but also for the remote reference sites (hand dorsum and hand palmar).
We interpret our results as pointing to changes in the nociceptive processing in CLBP at higher levels of the neuraxis, possibly thalamus and/or attentional control, rather than changes of spinal processing. Alternatively, there might be a higher vulnerability to noxious stimulation in CLBP patients.
PMCID: PMC3488472  PMID: 22998460
Chronic Low Back Pain (CLBP); Mechanical pain thresholds; Pinprick hyperalgesia; Allodynia
3.  Platelet Activity and Sensitivity to Agonists After Exhaustive Treadmill Exercise 
The extent of platelet activation after exhaustive exercise remains under discussion. Previous studies have provided contrary data, probably due to differences in the methodologies and the enrolled subjects. In the present study a maximal treadmill exercise (TR) was used to test platelet activity and -reactivity in 13 healthy non-smoking men. Blood samples were taken after a 30min rest, immediately before and after exercise, and 1h after completion of exercise. Platelets were analysed by whole blood flow cytometry either directly or after in vitro stimulation by incubating the blood samples for 10min with TRAP-6 (10µM) or ADP (5µM or 2,5µM). Binding of an anti-CD62P antibody or a PAC1 antibody directed against the activated fibrinogen receptor GPIIb/IIIa were used as a measure of platelet activation. Immediately after TR the percent CD62P positive platelets (%PC) unstimulated increased (p<0.01) from 0.77±0.06 to 1.12± 0.09 %PC and in PAC1 (p<0.05) from 2.32 ±0.54 to 3.83±0.81 %PC (mean±SEM). After ADP-stimulation an increase from 4.18±1.02 to 5.69±1.40 %PC in CD62P (p<0.01) and from 45.7±3.4 to 57.9±6.6 %PC in PAC1 (p<0.05) after TR were detected. Using TRAP-6-stimulation only the increase of PAC1 (p<0.01) after TR was different in comparison with the control experiment without exercise. Soluble CD62P in plasma as a marker of platelet and endothelial cell activation was also enhanced (p<0.05) after TR. Although these results indicate that exhaustive exercise lead to a small platelet activation and an increase in platelet reactivity, it is rather doubtful that these changes alone implicate a prothrombotic situation in healthy young non-smokers.
PMCID: PMC3937570  PMID: 24616605
Platelet activation; CD62P; PAC1; sCD62P; physical activity

Results 1-3 (3)