Physiological research
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Physiological research · Jan 2015
Development of causal interactions between systolic blood pressure and inter-beat intervals in adolescents.
Systolic blood pressure (SBP) changes control the cardiac inter-beat intervals (IBI) duration via baroreflex. Conversely, SBP is influenced by IBI via non-baroreflex mechanisms. Both causal pathways (feedback - baroreflex and feedforward - non-baroreflex) form a closed loop of the SBP - IBI interaction. ⋯ We conclude that the feedforward influence dominated at rest. The increase of Gain(SBP,IBI) with age was not found in the closed loop model. A decrease of Coh(SBP->IBI) could be related to a change in the cardiovascular control system complexity during maturation.
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Physiological research · Jan 2015
Head-up tilt rapidly compromises hemodynamics in healthy anesthetized swine.
The aims were to explore the effect of head-up tilt (HUT) to 30 and 60 degrees on hemodynamics and tissue oxygenation in anesthetized healthy swine. The data serve as a reference for a study of resuscitation efficacy at HUT such as during transport. Nine healthy swine (49+/-4 kg) were anesthetized and multiple sensors including myocardial pressure-volume loops catheter, carotid flow probe, blood pressure catheters, near infrared spectroscopy (NIRS) tissue oximetry and mixed venous oximetry (SVO2) catheter were introduced and parameters continuously recorded. ⋯ The values are means. In conclusions, within minutes, both 30 and 60 degrees head-up tilting is poorly tolerated in anesthetized swine. Significant differences among individual animals exist.
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Physiological research · Jan 2013
Controlled Clinical TrialRepetitive transcranial magnetic stimulation in the treatment of chronic orofacial pain.
Repetitive transcranial magnetic stimulation (rTMS) is non-invasive neuromodulation method. We applied rTMS for the treatment of farmacoresistant chronic orofacial pain. We compared the effect of 10 Hz and 20 Hz stimulation. ⋯ Only the results obtained in a series of five rTMS treatments in the first step (active n=24, sham n=12), that 20 Hz frequency rTMS using a higher intensity (95 % of motor threshold) to be equally effective relative to VAS (Visual analogue scale) and QST (quantitative sensory testing). In conclusions, the better results with the relief of orofacial pain were obtained with 20 Hz stimulation if compared with 10 Hz stimulation. It was proved with subjective (VAS) and objective evaluation (QST). rTMS can be used in the treatment of chronic intractable pain.
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Physiological research · Jan 2013
Diagnostic significance of a mild decrease of baroreflex sensitivity with respect to heart rate in type 1 diabetes mellitus.
Decreased baroreflex sensitivity is an early sign of autonomic dysfunction in patients with type-1 diabetes mellitus. We evaluated the repeatability of a mild baroreflex sensitivity decrease in diabetics with respect to their heart rate. Finger blood pressure was continuously recorded in 14 young diabetics without clinical signs of autonomic dysfunction and in 14 age-matched controls for 42 min. ⋯ Thus, BRS reflects not only an impairment of the quick baroreflex responses of IBI to blood pressure changes, but also a change of the tonic sympathetic and parasympathetic heart rate control. This is of significance during mild changes of BRS. Therefore, an examination of the BRSf index is highly recommended, because this examination improves the diagnostic value of the measurement, particularly in cases of early signs of autonomic dysfunction.
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Physiological research · Jan 2013
Development of heat hyperalgesia and changes of TRPV1 and NGF expression in rat dorsal root ganglion following joint immobilization.
The aim of this study was to examine whether threshold to heat stimuli, and expression of transient receptor potential vanilloid1 (TRPV1) and nerve growth factor (NGF) in dorsal root ganglion (DRG) altered under conditions of long-term limb immobilization. A plastic cast was wrapped around the right limb from the forearm to the forepaw to keep wrist joint at 90° of flexion for 5 weeks. Heat hyperalgesia was tested using the plantar test at 6 h after removing cast. ⋯ Ipsilateral percentage of immunoreactive neurons in the total DRG neurons was significantly higher than contralateral sides in TRPV1-IR and NGF-IR. Long-term casting induced heat hyperalgesia, and up-regulation and phenotypic change of TRPV1-IR and NGF-IR in DRGs on the immobilized side. These DRG alterations may involve heat hyperalgesia after long-term limb immobilization.