Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Jan 2012
Technetium-99m-labelled HL91 and technetium-99m-labelled MIBI SPECT imaging for the detection of ischaemic viable myocardium: a preliminary study.
The assessment of myocardial viability has become an important aspect of the diagnostic and prognostic work-up of patients with coronary artery disease. Technetium-99m labelled sestamibi ((99m)Tc-MIBI) myocardial perfusion imaging may underestimate the viability of ischaemic myocardium. Technetium-99m labelled 4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime ((99m)Tc-HL91) is a hypoxia-avid agent which can identify acutely ischaemic viable myocardium in a canine model using a standard gamma camera. The aim of this study was to evaluate uptake character of ischaemic viable myocardium and diagnostic performance of single-photon emission computed tomography (SPECT) imaging by (99m)Tc-HL91 and (99m)Tc-MIBI in detecting ischaemic viable myocardium in coronary heart disease. ⋯ Functional SPECT imaging with (99m)Tc-HL91 and (99m)Tc-MIBI can be used to detect the seriously ischaemic but viable myocardium with a mismatched uptake character. The uptake of (99m)Tc-HL91 in the viable myocardium reached a stable level at 3-4 h after injection.
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Clin Physiol Funct Imaging · Jan 2012
Correlation between serum calcium levels and dual-phase (99m)Tc-sestamibi parathyroid scintigraphy in primary hyperparathyroidism.
The goal of the study is to correlate serum calcium levels with the results of dual-phase (99m)Tc-sestamibi parathyroid scintigraphy to find the best cut-off level of the serum calcium that correlates with a positive presurgery. ⋯ (99m)Tc-MIBI parathyroid scintigraphy is most likely to yield identification and localization of a parathyroid adenoma when both PTH and calcium are elevated; however, although there is no lower limit of PTH which can predict a negative study, we cannot recommend (99m)Tc-MIBI parathyroid scintigraphy if the serum calcium is <2·51 mmol l(-1).
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Clin Physiol Funct Imaging · Nov 2011
Randomized Controlled TrialTRPV1 and TRPA1 stimulation induces MUC5B secretion in the human nasal airway in vivo.
Nasal transient receptor potential vanilloid 1 (TRPV1) stimulation with capsaicin produces serous and mucinous secretion in the human nasal airway. The primary aim of this study was to examine topical effects of various TRP ion channel agonists on symptoms and secretion of specific mucins: mucin 5 subtype AC (MUC5AC) and B (MUC5B). ⋯ Agonists of TRPV1 and TRPA1 induced MUC5B release in the human nasal airways in vivo. These findings may be of relevance with regard to the regulation of mucin production under physiological and pathophysiological conditions.
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Clin Physiol Funct Imaging · Nov 2011
Randomized Controlled TrialThe effect of phenylephrine on arterial and venous cerebral blood flow in healthy subjects.
Sympathetic regulation of the cerebral circulation remains controversial. Although intravenous phenylephrine (PE) infusion reduces the near-infrared spectroscopy (NIRS)-determined measure of frontal lobe oxygenation (S(c) O(2) ) and increases middle cerebral artery mean blood velocity (MCA V(mean) ), suggesting α-adrenergic-mediated cerebral vasoconstriction, this remains unconfirmed by evaluation of arterial and venous cerebral blood flow. ⋯ These findings confirm that PE induces a reduction in S(c) O(2) measured by NIRS and causes an increase in MCA V(mean) indicative of cerebral arterial vasoconstriction, although ICA was preserved and IJV increased. These results suggest that a decrease in S(c) O(2) during infusion of PE reflects an altered cerebral contribution of arterial versus venous blood to the NIRS signal, although we cannot rule out that an effect of PE on skin blood flow is important.
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Clin Physiol Funct Imaging · Nov 2011
The dynamics of the microcirculation in the subcutaneous adipose tissue is impaired in the postprandial state in type 2 diabetes.
Postprandially, the blood flow and uptake of non-esterified fatty acids increase concomitantly in the abdominal subcutaneous adipose tissue in healthy subjects. In insulin-resistant subjects, this postprandial blood flow increase is blunted. We have previously found that the postprandial adipose tissue blood flow (ATBF) increase is accompanied by capillary recruitment in healthy subjects. The aim of the present study was to investigate whether the postprandial capillary recruitment in adipose tissue is affected in type 2 diabetes mellitus. Eight type 2 diabetic overweight male subjects and eight age- and weight-matched healthy subjects were studied. Contrast-enhanced ultrasound imaging was applied to study the microvascular volume in abdominal subcutaneous adipose tissue and in forearm skeletal muscle in the fasting state and 60, 120 and 180 min after a 75-g oral glucose load. Abdominal subcutaneous ATBF was measured using (133) Xenon washout technique, and forearm skeletal muscle blood flow was assessed by venous occlusion plethysmography. In the healthy, overweight subjects, ATBF increased and concomitantly capillary recruitment took place after glucose ingestion. No significant changes were found in the ATBF or in capillary recruitment in the type 2 diabetic subjects. There was no significant blood flow or microvascular blood volume changes in forearm skeletal muscle in either of the groups. ⋯ After an oral glucose load, the abdominal ATBF and microvascular blood volume changes in abdominal subcutaneous adipose tissue are impaired in overweight type 2 diabetic subjects compared to weight-matched healthy subjects.