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  1. Assessment of renal flow and flow reserve in humans
    Autor*in: Manoharan, G ; Pijls, NHJ ; Lameire, N ; Verhamme, K ; Heyndrickx, GR ; Wijns, W ; Madaric, J ; Tielbeele, X ; Bartunek, J ; De Bruyne, B. ; BARBATO, EMANUELE
    Erschienen: 2006

    OBJECTIVES: The purpose of this work was to establish the normal range of maximal renal hyperemic response in humans and to identify the ideal renal vasodilatory stimuli. BACKGROUND: Stenotic renovascular atherosclerosis is increasingly treated by... mehr

     

    OBJECTIVES: The purpose of this work was to establish the normal range of maximal renal hyperemic response in humans and to identify the ideal renal vasodilatory stimuli. BACKGROUND: Stenotic renovascular atherosclerosis is increasingly treated by percutaneous transluminal renal intervention but with an unpredictable outcome. This may be due to hemodynamically non-significant stenosis or the presence of irreversible damage to the glomerular circulation. We propose that the renovascular hyperemic response may help identify appropriate patients. METHODS: In 28 normotensive patients, quantitative angiographic measurements of the renal artery were obtained, and renal artery pressure and flow velocity were continuously recorded after various hyperemic agents. RESULTS: In a first group of 11 patients, a significant increase in renal artery average peak velocity (APV) was observed after intrarenal (IR) bolus injection of 600 μg isosorbide dinitrate (41 ± 19%), 30 mg papaverine (50 ± 34%), 50 μg dopamine (94 ± 54%), 0.8 μg·kg-1 fenoldopam (80 ± 25%), and during IR infusion of 1 μg·kg-1·min-1 fenoldopam (86 ± 28%). A second group of 17 patients received intravenous infusion of dopamine (3, 5, 10, 20, 30, and 40 μg·kg -1·min-1). The 3 and 5 μg·kg -1·min-1 of dopamine modestly reduced renal resistance index (RI) (-13 ± 15% and -25 ± 20%, respectively). At higher dosages, no further decline in RI was observed. No significant change in vessel diameter was observed before and after the administration of the pharmacological stimuli suggesting that changes in APV corresponded with changes in absolute renal blood flow. CONCLUSIONS: The normal renal flow reserve averages approximately 2 in humans with normal renal function. An IR bolus injection of 50 μg·kg-1 of dopamine is the most convenient means to elicit maximal renal hyperemia. © 2006 by the American College of Cardiology Foundation.

     
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  2. Pressure-derived measurement of coronary flow reserve
    Autor*in: MacCarthy, P ; Berger, A ; Manoharan, G ; Bartunek, J ; Wijns, W ; Heyndrickx, GR ; Pijls NHJ ; De Bruyne, B. ; BARBATO, EMANUELE
    Erschienen: 2005

    We aimed to validate the technique of measuring the coronary flow reserve (CFR) with coronary pressure measurements against an established thermodilution technique. The CFR has traditionally required measurement of coronary blood flow velocity with... mehr

     

    We aimed to validate the technique of measuring the coronary flow reserve (CFR) with coronary pressure measurements against an established thermodilution technique. The CFR has traditionally required measurement of coronary blood flow velocity with the Doppler wire and, more recently, using a thermodilution technique with the coronary pressure wire. However, recent work has suggested that the CFR may be derived from pressure measurements alone (the ratio of the square root of the pressure drop across an epicardial stenosis during hyperemia to that value at rest). This depends on the assumption that friction losses across a coronary stenosis are negligible. We compared pressure-derived CFR values with those obtained by the thermodilution technique using the intracoronary pressure wire in 38 stenoses in 34 patients with significant coronary stenoses undergoing percutaneous intervention. We also compared these two techniques of measuring CFR in 25 stenoses (6 vessels) artificially created by inflating small balloons within a stented coronary artery after percutaneous intervention. There is a close linear relationship between pressure-derived and thermodilution CFR in native (r 2 = 0.52; p < 0.001) and artificial stenoses (r 2 = 0.54; p < 0.05), although the pressure-derived technique appears to systematically underestimate CFR values in both situations. This applies to native and artificial stenoses. Coronary flow reserve cannot be measured merely with pressure alone, and it cannot be safely assumed that friction losses are negligible across a native coronary stenosis. These data suggest that friction loss is an important determinant of the pressure gradient along an atherosclerotic coronary artery. © 2005 by the American College of Cardiology Foundation.

     
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  3. Adipose tissue transcriptome reflects variations between subjects with continued weight loss and subjects regaining weight 6 mo after caloric restriction independent of energy intake.
    Autor*in: Márquez-Quiñones, Adriana ; Mutch, David, ; Debard, Cyrille ; Wang, Ping ; Combes, Marion ; Roussel, Balbine ; Holst, Claus ; Martinez, J Alfredo ; Handjieva-Darlenska, Teodora ; Kalouskova, Pavla ; Jebb, Susan ; Babalis, Dimitris ; Pfeiffer, Andreas, ; Larsen, Thomas, ; Astrup, Arne ; Saris, Wim, ; Mariman, Edwin ; Clément, Karine ; Vidal, Hubert ; Langin, Dominique ; Viguerie, Nathalie
    Erschienen: 2010
    Verlag:  HAL CCSD ; Oxford University Press

    International audience ; BACKGROUND: The mechanisms underlying body weight evolution after diet-induced weight loss are poorly understood. OBJECTIVE: We aimed to identify and characterize differences in the subcutaneous adipose tissue (SAT)... mehr

     

    International audience ; BACKGROUND: The mechanisms underlying body weight evolution after diet-induced weight loss are poorly understood. OBJECTIVE: We aimed to identify and characterize differences in the subcutaneous adipose tissue (SAT) transcriptome of subjects with different weight changes after energy restriction-induced weight loss during 6 mo on 4 different diets. DESIGN: After an 8-wk low-calorie diet (800 kcal/d), we randomly assigned weight-reduced obese subjects from 8 European countries to receive 4 diets that differed in protein and glycemic index content. In addition to anthropometric and plasma markers, SAT biopsies were taken at the beginning [clinical investigation day (CID) 2] and end (CID3) of the weight follow-up period. Microarray analysis was used to define SAT gene expression profiles at CID2 and CID3 in 22 women with continued weight loss (successful group) and in 22 women with weight regain (unsuccessful group) across the 4 dietary arms. RESULTS: Differences in SAT gene expression patterns between successful and unsuccessful groups were mainly due to weight variations rather than to differences in dietary macronutrient content. An analysis of covariance with total energy intake as a covariate identified 1338 differentially expressed genes. Cellular growth and proliferation, cell death, cellular function, and maintenance were the main biological processes represented in SAT from subjects who regained weight. Mitochondrial oxidative phosphorylation was the major pattern associated with continued weight loss. CONCLUSIONS: The ability to control body weight loss independent of energy intake or diet composition is reflected in the SAT transcriptome. Although cell proliferation may be detrimental, a greater mitochondrial energy gene expression is suggested as being beneficial for weight control. This trial was registered at clinicaltrials.gov as NCT00390637.

     
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