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P Melon

Publications and source records attributed to P Melon.

9 recordsLinked to original sources
PubMed2001

Positron emission tomography using(18)F-fluoro-deoxyglucose and euglycaemic hyperinsulinaemic glucose clamp: optimal criteria for the prediction of recovery of post-ischaemic left ventricular dysfunction. Results from the European Community Concerted Action Multicenter study on use of(18)F-fluoro-deoxyglucose Positron Emission Tomography for the Detection of Myocardial Viability.

AIMS: To assess the accuracy of positron emission tomography to predict recovery of global cardiac function after revascularization in patients with coronary artery disease. METHODS AND RESULTS: One hundred and seventy-eight patients (157 male, 58+/-10 years) with coronary artery disease and left ventricular dysfunction (mean ejection fraction 39+/-14%) were enrolled in six European centres. They underwent a common protocol for the assessment of viability using(18)F-fluoro-2-deoxyglucose (FDG) positron emission tomography during a standardized euglycaemic hyperinsulinaemic glucose clamp before revascularization by either surgery (n=140) or angioplasty (n=38). Seven patients were excluded because of incomplete revascularization of a dysfunctional region. Based on the recovery of global ejection fraction 2-6 months after revascularization, patients were classified into two groups: 82 patients who had a >5% improvement in ejection fraction postoperatively, and 89 patients without postoperative ejection fraction improvement. Optimal cut-off points for postoperative improvement of global cardiac function were computed, using receiver operating curve analysis. The highest sensitivity (79%) and specificity (55%) for predicting postoperative ejection fraction improvement by positron emission tomography was found when three or more dysfunctional segments had a relative FDG uptake >45% of normal remote myocardium (overall accuracy 67%). CONCLUSIONS: In a large cohort of coronary patients with impaired ejection fraction, FDG positron emission tomography demonstrated high sensitivity and moderate specificity to predict improvement of cardiac function after coronary revascularization.

Adult↗
PubMed1999

[Pharma-clinics. How I treat vasovagal syncope].

Vaso-vagal syncope is generally thought to be triggered by a short episode of sympathetic stimulation immediately followed by an inappropriate reflex hemodynamic response (bradycardia-hypotension). The patient should be reassured and informed about the symptoms which precede syncope and about the benefit that muscular contractions of the legs may provide. Elastic stocking support may be useful. When pharmacological treatment is necessary, betablockers will be the initial choice for patients in whom syncope is clearly preceded by a sympathetic rise. In other instances, the treatment is less well delineated and may consist of fluid-NaCl therapy with fluorocortisone, or possibly an alpha-agonist, or a specific inhibitor of serotonin reuptake. Bi-chamber pacing should be reserved for patients with a marked cardio-inhibitory response and severe, frequently recurrent syncope. The benefit of tilt training deserves confirmation.

Adrenergic alpha-Agonists↗
PubMed1997

[Vasovagal syncope].

Explore the source record for details and available documents.

Adrenergic beta-Antagonists↗
PubMed1995

Noninvasive quantification of regional myocardial flow reserve in patients with coronary atherosclerosis using nitrogen-13 ammonia positron emission tomography. Determination of extent of altered vascular reactivity.

OBJECTIVES: The aim of this study was to evaluate patients with coronary artery disease to 1) determine the relation between flow reserve measured by nitrogen-13 (N-13) ammonia kinetic modeling and stenosis severity assessed by quantitative angiography, and 2) examine whether flow reserve is impaired in regions supplied by vessels without significant angiographic disease. BACKGROUND: With the advent of new therapeutic approaches for coronary disease, an accurate noninvasive approach for absolute quantification of flow and flow reserve is needed to evaluate functional severity and extent of atherosclerosis. Nitrogen-13 ammonia kinetic modeling may permit such evaluation. METHODS: Twenty-seven subjects were classified into three groups: group 1 = 5 young volunteers: group 2 = 7 middle-aged volunteers; and group 3 = 15 patients with coronary artery disease. Dynamic N-13 ammonia positron emission tomographic imaging was performed at rest and during adenosine infusion. A three-compartment model was fit to regional N-13 ammonia kinetic data to determine myocardial flow. Group 3 patients underwent quantitative coronary angiography. RESULTS: The regional blood flow results in patients with coronary disease were classified into four subgroups: no significant detectable disease and mild (50% to 69.9% area stenosis), moderate (70% to 94.9% area stenosis) or severe (95% to 100% area stenosis) coronary disease. Flow reserve was 2.95 +/- 0.65; 2.09 +/- 0.47; 2.02 +/- 0.51; 1.3 +/- 0.32, respectively (p < or = 0.01 except mild vs. moderate). Flow reserve was correlated with percent area stenosis (r = -0.56) and minimal lumen diameter (r = 0.75). In volunteers (groups 1 and 2), flow reserves were greater than in segments without detectable disease in group 3 patients (4.10 +/- 0.71 and 3.79 +/- 0.42, respectively, vs. 2.88 +/- 0.56, p < or = 0.02). CONCLUSIONS: The functional severity of coronary disease measured by N-13 ammonia positron emission tomography varied for a given stenosis but was significantly related to angiographic severity. Among patients with coronary disease, myocardial regions without significant angiographic stenoses displayed reduced flow reserve than did regions in control subjects, indicating that vascular reactivity was more diffusely impaired in group 3 than was suggested by angiography. Noninvasive quantification of myocardial flow reserve using dynamic N-13 ammonia positron emission tomography yields important functional data that permit definition of the extent of disease even when disease is not apparent by angiography.

Adenosine↗
PubMed1995

Fluorine-18-fluorodeoxyglucose positron emission tomography for preoperative parathyroid imaging in primary hyperparathyroidism.

Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging was performed in seven consecutive patients with primary hyperparathyroidism to preoperatively locate parathyroid adenomas. Foci of FDG accumulation corresponding to abnormal parathyroid tissue were observed in two out of nine surgically excised parathyroid adenomas. It was concluded that FDG PET imaging demonstrated a too low sensitivity for systematic preoperative detection and localization of parathyroid glands causing primary hyperparathyroidism.

Adenoma↗
PubMed1990

Imaging of myocardial metabolism by positron emission tomography.

Tracer techniques have provided new insight in cardiology by allowing noninvasive studies of myocardial perfusion, function, metabolism, and, more recently, ligand-receptor interaction. Positron emission tomography allows accurate quantification and the use of natural substrates labelled with 11C, 13N, or 15O. Myocardial metabolism is complex and utilizes a number of substrates, primarily fatty acids. Fatty acids utilization can be studied with 11C palmitate, while 11C acetate more selectively traces TCA cycle activity and reflects myocardial oxygen utilization. Glucose uptake can be traced using 18F deoxyglucose, a glucose analog that is a substrate for hexokinase but is not further metabolized. Flow and oxidative glucose metabolism are usually coupled, and thereby the uptake of FDG and perfusion tracers are usually similar. In myocardial ischemia, however, glucose utilization can persist due to anaerobic glycolysis, and its uptake is frequently enhanced. Clinical applications of the use of metabolic studies in patients with ischemic heart disease are presented.

Amino Acids↗
PubMedDate not supplied

Metabolic imaging by positron emission tomography early after myocardial infarction as a predictor of recovery of myocardial function after reperfusion.

BACKGROUND: Myocardial ischemia leads to alterations in myocardial substrate metabolism that have been shown to reflect severity of ischemic injury. The purpose of this study was to correlate oxidative metabolism with recovery of contractile function in patients with acute myocardial infarction. METHODS AND RESULTS: Regional blood flow and oxidative metabolism were assessed by dynamic positron emission tomography early after myocardial infarction treated with thrombolytic therapy in 18 patients. The extent of myocardial perfusion abnormally (carbon 11-labeled acetate uptake; relative amplitude < or = 50%) was inversely correlated with the ejection fraction obtained within 8 hours of the onset of chest pain (r = -0.81; p - 0.01) but not clearly with that at follow-up 1 week later (r = 0.64; p = 0.09). Oxidative metabolism (carbon 11-labeled acetate; monoexponential clearance) was higher in periinfarct territories with early or late recovery of contractile function than in those without, but there was a large overlap in absolute values limiting the predictive power of a single measurement. Relatively preserved oxidative metabolism compared with perfusion in low-flow areas was predictive of early (day 1 to 1 week) and delayed (week 1 to beyond 1 month) recovery. Normal resting perfusion with regionally decreased oxidative metabolism predicted early recovery of contractile function. CONCLUSION: Thus in patients studied with positron emission tomography early after myocardial infarction, comparison of regional perfusion and oxidative metabolism was more predictive of recovery in contractile function than was assessment of either one alone.

Adult↗
PubMedDate not supplied

Laparoscopic adrenalectomy in pheochromocytoma and Cushing's syndrome. Reflections about two case reports.

Laparoscopic adrenalectomy is possible as well on the left as on the right side using a percutaneous transabdominal approach. The exposure of the glands seems better than it could be achieved with an open method. In combination with intraoperative infusion of nicardipine, a calcium-channel blocker, the laparoscopic removal of a pheochromocytoma was performed safely and under stable conditions. In case of Cushing's syndrome, the laparoscopic approach reduces the problems related to poor healing. In all cases of laparoscopic adrenalectomy, this approach could offer the clear advantages of smaller incisions, reduced postoperative pain and incisional discomfort as well as complications related to large and invasive procedure and finally allows quicker recovery. Moreover, conversion to open surgery remains always possible, if needed.

Adrenal Gland Neoplasms↗