Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Nov 2011
Evidence of diminished coronary flow in pulmonary hypertension: explaining angina pectoris in this patient group?
Many patients with pulmonary hypertension (PH) have symptoms of angina without evidence of occlusive coronary artery disease. For the first time, this study addresses the influence of progressively increasing pulmonary artery pressure (PAP) on left anterior descending artery flow in a rat model of PH. The role of pulmonary artery dilatation, septal wall motion abnormality, cardiac output or diastolic blood pressure in determining coronary blood flow (CBF) during PH was determined. ⋯ Coronary flow reduction in murine PH has potential to be clinically meaningful and should therefore further studied in a clinical trial.
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Peak brachial artery dilation post-nitroglycerin (NTG) administration occurs between 3 and 5 min in adults. The purpose of this study was to identify the time to peak dilation response to sublingual NTG (0·3 mg) in youth. Endothelium-independent dilation (EID) was measured in 198 healthy (113 males, 85 females) youth (6-18 years) via ultrasound imaging of the brachial artery following NTG administration. ⋯ Peak EID (males: 24·8 ± 0·5 versus females: 25·3 ± 0·6%, P = 0·6) was not significantly different after accounting for baseline diameter. Peak response to NTG administration occurs between 4 and 5 min. The results demonstrate the importance of measuring EID up to 5-min post-NTG administration in youth.
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Clin Physiol Funct Imaging · Sep 2011
Review Historical ArticleAn assessment of pulmonary function testing and ventilatory kinematics by optoelectronic plethysmography.
New advances in computer processing and imaging have allowed the development of innovative techniques to assess lung function. A promising methodology is optoelectronic plethysmography (OEP). ⋯ Currently, this system is used mainly in research settings, but in the future may have broad applicability to patient populations such as very young children, patients with neuromuscular disease and patients who cannot be tested with classical spirometry testing. This paper presents the history and development of OEP, along with a summary of the OEP methodology, a discussion of research findings and results to date, as well as application and limitations.
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Clin Physiol Funct Imaging · Sep 2011
Randomized Controlled Trial Comparative StudyConventional versus acupuncture-like transcutaneous electrical nerve stimulation on cold-induced pain in healthy human participants: effects during stimulation.
To compare the hypoalgesic effects of conventional transcutaneous electrical nerve stimulation (TENS) (high frequency, low intensity) and acupuncture-like TENS (AL-TENS, low frequency, high intensity) on cold-induced pain. ⋯ Unlike some previous studies, the present study detected no differences in hypoalgesia between AL-TENS, conventional TENS and placebo (no current) TENS during stimulation.
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Clin Physiol Funct Imaging · Sep 2011
Reproducibility and sensitivity of muscle reoxygenation and oxygen uptake recovery kinetics following running exercise in the field.
The purpose of this study was to assess the reliability of postexercise near-infrared spectroscopy (NIRS)-derived measurements and their sensitivity to different exercise intensities in the field. Seventeen athletes (24·1 ± 5·6 year) repeated, on three occasions, two 2-min submaximal shuttle-runs at 40% and 60% of V(IFT) (final speed of the 30-15 intermittent fitness test) and a 50-m shuttle-run sprint (Sprint), with (OCC) or without (CON) repeated transient arterial occlusions of the medial gastrocnemius during the postexercise period. NIRS variables (i.e. oxyhaemoglobin [HbO(2)], deoxyhaemoglobin [HHb] and their difference [Hb(diff)]) were measured continuously for 3 min after each exercise. ⋯ While running, intensity did not affect MRT or ½Rec for muscle reoxygenation, and differences were found for mVO(2) recovery (e.g. [Hb(diff)]-mVO(2) MRT = 28·7 ± 5·2, 34·2 ± 5·1 and 37·3 ± 6·2 s for 40%, 60% and Sprint, respectively, P<0·01). To conclude, the kinetics of postexercise NIRS measurements showed CV values ranging from 6% to 37%, with no substantial differences between exercise intensities or NIRS-derived variables. However, exercise intensity did influence mVO(2) recovery kinetics, but not that of muscle reoxygenation in an occlusion-free condition.