Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Jul 2010
Randomized Controlled Trial Comparative StudyA comparison of transcutaneous electrical nerve stimulation (TENS) at 3 and 80 pulses per second on cold-pressor pain in healthy human participants.
Electrophysiological studies suggest that there are differential frequency effects during TENS. The aim of this experimental study was to assess the effects of strong non-painful TENS administered at 3 pulses per second (pps) and 80 pps on cold-pressor pain in healthy human participants. A repeated measure design was used with participants receiving TENS at 3 pps and 80 pps in the same experiment. ⋯ The differences after 15 min of TENS were 1.70 s to 3.70 s (95% CI) for threshold and 6.63-15.5 mm (95% CI) for pain intensity. In conclusion, strong non-painful TENS at 3 pps was superior to 80 pps at reducing experimentally induced cold-pressor pain. The implications of these findings are discussed.
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Clin Physiol Funct Imaging · Jul 2010
Comparative StudyMuscle tissue oxygenation and VEGF in VO-matched vibration and squatting exercise.
Exposure to vibration has traditionally been associated with compromised perfusion. This study investigated whether blood supply during whole body vibration (WBV), as an exercise modality, is in proportion to the metabolic demand by the contracting musculature. As a secondary aim, serum levels of vascular endothelial growth factor (VEGF) were assessed. ⋯ These results suggest that oxygen supply during WBV is sufficient, and oxygenation is even enhanced during the first approximately 30 s. Most likely, the transient response is because of local vascular regulatory mechanisms and due to muscle contraction mechanics. This might become clinically relevant under pathological conditions, e.g. in vascular disorders.
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Clin Physiol Funct Imaging · Jul 2010
No change in the regional distribution of tidal volume during lateral posture in mechanically ventilated patients assessed by electrical impedance tomography.
We assessed the distribution of regional lung ventilation during moderate and steep lateral posture using electrical impedance tomography (EIT) in mechanically ventilated patients. Seven patients were placed on a kinetic treatment table. An elastic belt containing 16 electrodes was placed around the chest and was connected to the EIT device. ⋯ In right lateral positions, a broader variation of V(T) with a trend towards an increase in the dependently positioned lung was observed in comparison with supine. Lateral positioning promotes the redistribution of ventilation to the ventral regions of the lung. The use of EIT technology might become a helpful tool for understanding and guiding posture therapy in mechanically ventilated patients.
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Clin Physiol Funct Imaging · Jul 2010
Spinal long-term potentiation is associated with reduced opioid neurotransmission in the rat brain.
Neuronal events leading to development of long-term potentiation (LTP) in the nociceptive pathways may be a cellular mechanism underlying hyperalgesia. In the present study, we examine if induction of spinal LTP may be associated with functional changes in the supraspinal opioidergic system. The opioid receptors (ORs) play a key role in nociceptive processing and controlling the descending modulatory system to the spinal cord. ⋯ HFS conditioning of the sciatic nerve resulted in both spinal LTP and functional changes in supraspinal opioidergic signalling. Our findings suggest that induction of spinal LTP may be associated with reduced opioid neurotransmission in brain regions involved in pain modulation and affective-emotional responses.