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MRI inulin

Luigi Granato, Luce Vander Elst, Celine Henoumont, Robert N Muller, Sophie Laurent
Thanks to the understanding of the relationships between the residence lifetime τM of the coordinated water molecules to macrocyclic Gd-complexes and the rotational mobility τR of these structures, and according to the theory for paramagnetic relaxation, it is now possible to design macromolecular contrast agents with enhanced relaxivities by optimizing these two parameters through ligand structural modification. We succeeded in accelerating the water exchange rate by inducing steric compression around the water binding site, and by removing the amide function from the DOTA-AA ligand [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono(p-aminoanilide)] (L) previously designed...
February 2018: Chemistry & Biodiversity
Kai Jiang, Hui Tang, Prasanna K Mishra, Slobodan I Macura, Lilach O Lerman
PURPOSE: To develop and validate a method for measuring murine single-kidney glomerular filtration rate (GFR) using dynamic contrast-enhanced MRI (DCE-MRI). METHODS: This prospective study was approved by the Institutional Animal Care and Use Committee. A fast longitudinal relaxation time (T1 ) measurement method was implemented to capture gadolinium dynamics (1 s/scan), and a modified two-compartment model was developed to quantify GFR as well as renal perfusion using 16...
June 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Giles Major, Sue Pritchard, Kathryn Murray, Jan Paul Alappadan, Caroline L Hoad, Luca Marciani, Penny Gowland, Robin Spiller
BACKGROUND & AIMS: Poorly digested, fermentable carbohydrates may induce symptoms of irritable bowel syndrome (IBS) via unclear mechanisms. We performed a randomized trial with magnetic resonance imaging (MRI) analysis to investigate correlations between symptoms and changes in small- and large-bowel contents after oral challenge. METHODS: We performed a 3-period, cross-over study of 29 adult patients with IBS (based on Rome III criteria, with symptoms of abdominal pain or discomfort for at least 2 days/wk) and reported bloating...
January 2017: Gastroenterology
Mark M Smits, Lennart Tonneijck, Marcel H A Muskiet, Trynke Hoekstra, Mark H H Kramer, Indra C Pieters, Djuna L Cahen, Michaela Diamant, Daniël H van Raalte
INTRODUCTION: Incretin-based therapies, that is, glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors, are relatively novel antihyperglycaemic drugs that are frequently used in type 2 diabetes management. Apart from glucose-lowering, these agents exhibit pleiotropic actions that may have favourable and unfavourable clinical consequences. Incretin-based therapies have been associated with heart rate acceleration, heart failure, acute renal failure and acute pancreatitis...
November 19, 2015: BMJ Open
Kathryn Murray, Victoria Wilkinson-Smith, Caroline Hoad, Carolyn Costigan, Eleanor Cox, Ching Lam, Luca Marciani, Penny Gowland, Robin C Spiller
OBJECTIVES: The objective of this study was to investigate whether ingestion of fructose and fructans (such as inulin) can exacerbate irritable bowel syndrome (IBS) symptoms. The aim was to better understand the origin of these symptoms by magnetic resonance imaging (MRI) of the gut. METHODS: A total of 16 healthy volunteers participated in a four-way, randomized, single-blind, crossover study in which they consumed 500 ml of water containing 40 g of either glucose, fructose, inulin, or a 1:1 mixture of 40 g glucose and 40 g fructose...
January 2014: American Journal of Gastroenterology
Tulika Arora, Ruey Leng Loo, Jelena Anastasovska, Glenn R Gibson, Kieran M Tuohy, Raj Kumar Sharma, Jonathan R Swann, Eddie R Deaville, Michele L Sleeth, E Louise Thomas, Elaine Holmes, Jimmy D Bell, Gary Frost
BACKGROUND: Obesity is rising at an alarming rate globally. Different fermentable carbohydrates have been shown to reduce obesity. The aim of the present study was to investigate if two different fermentable carbohydrates (inulin and β-glucan) exert similar effects on body composition and central appetite regulation in high fat fed mice. METHODOLOGY/PRINCIPAL FINDINGS: Thirty six C57BL/6 male mice were randomized and maintained for 8 weeks on a high fat diet containing 0% (w/w) fermentable carbohydrate, 10% (w/w) inulin or 10% (w/w) β-glucan individually...
2012: PloS One
Jelena Anastasovska, Tulika Arora, Gina J Sanchez Canon, James R C Parkinson, Kieran Touhy, Glen R Gibson, Nachiket A Nadkarni, Po-Wah So, Anthony P Goldstone, E Louise Thomas, Mohammed K Hankir, Jan Van Loo, Neena Modi, Jimmy D Bell, Gary Frost
Obesity has become a major global health problem. Recently, attention has focused on the benefits of fermentable carbohydrates on modulating metabolism. Here, we take a system approach to investigate the physiological effects of supplementation with oligofructose-enriched inulin (In). We hypothesize that supplementation with this fermentable carbohydrate will not only lead to changes in body weight and composition, but also to modulation in neuronal activation in the hypothalamus. Male C57BL/6 mice were maintained on a normal chow diet (control) or a high fat (HF) diet supplemented with either oligofructose-enriched In or corn starch (Cs) for 9 weeks...
May 2012: Obesity
Luigi Granato, Sophie Laurent, Luce Vander Elst, Kristina Djanashvili, Joop A Peters, Robert N Muller
Reaction of DOTA-NCSA [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono(p-isothiocyanatoanilide)] with O-(aminopropyl)inulin (degree of polymerization 25) provided a chelate that formed a kinetically extremely stable Gd(3+) complex. No transmetalation was observed with Zn(2+). The conjugate has a relaxivity of 21.7 s(-1) mM(-1) at 20 MHz and 37 °C, and each molecule of the inulin carries on average 35 Gd(3+) ions. The parameters governing the relaxivity of this material and of a low-molecular-weight model compound prepared by conjugation of DOTA-NCSA and propylamine were evaluated by investigation of their water (1)H longitudinal relaxation rate enhancements at different magnetic fields (NMRD) and by studying variable temperature (17)O NMR data...
November 2011: Contrast Media & Molecular Imaging
Ambika Bumb, Martin W Brechbiel, Peter Choyke
Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers)...
September 2010: Acta Radiologica
Vladimir Teplan, Otto Schück, Jaroslav Racek, Olga Mareckova, Milena Stollova, Vladimir Hanzal, Jan Malý
BACKGROUND: Levels of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) are elevated in chronic kidney disease (CKD) and may contribute to vascular complications. In this study we tested the hypothesis that elevated ADMA can be reduced in obese CKD patients by long-term administration of a low-protein diet supplemented with keto-amino acids. PATIENTS AND METHODS: In a long-term prospective double-blind placebo-controlled randomized trial, we evaluated for a period of 36 months a total of 111 CKD patients (54 men, 57 women) aged 22-76 years with obesity (BMI >or= 30 kg/m(2)) and an inulin clearance rate (C(in)) of 22-40 ml/min/1...
2008: Wiener Klinische Wochenschrift
Petra Lebdusková, Jan Kotek, Petr Hermann, Luce Vander Elst, Robert N Muller, Ivan Lukes, Joop A Peters
A novel conjugate of a polysaccharide and a Gd(III) chelate with potential as contrast agent for magnetic resonance imaging (MRI) was synthesized. The structure of the chelate was derived from H5DTPA by replacing the central pendant arm by a phosphinic acid functional group, which was covalently bound to the polysaccharide inulin. On the average, each monosaccharide unit of the inulin was attached to approximately one (0.9) chelate moiety. The average molecular weight is 23110 and the average number of Gd3+ ions per molecule is 24...
July 2004: Bioconjugate Chemistry
Laurent Juillard, Lilach O Lerman, David G Kruger, John A Haas, Brian C Rucker, Jason A Polzin, Stephen J Riederer, Juan C Romero
BACKGROUND: Ischemic nephropathy is a common cause of end-stage renal disease. Exploration of the mechanisms of deterioration of renal function is limited due to lack of noninvasive techniques available to study the single kidney. The Blood Oxygen Level-Dependent (BOLD) MRI method can measure deoxyhemoglobin and therefore indirectly estimates renal oxygen content, but has never been evaluated in renal artery stenosis (RAS). This study was therefore designed to test if BOLD can detect the characteristic of renal hypoxia induced by RAS...
March 2004: Kidney International
Xavier Fulladosa, Francesc Moreso, Jose A Narváez, Josep M Grinyó, Daniel Serón
Glomerular number (N(g)) is considered a major determinant of renal function and outcome. In the dog, it has been shown that Ng can be estimated with reasonable precision in vivo by means of a renal biopsy and magnetic resonance imaging (MRI). Thus, this method was applied to study anatomoclinical correlations in stable human renal transplants. Thirty-nine stable renal transplants were included. A protocol renal allograft biopsy was done at 4 mo. Biopsies were evaluated according to Banff criteria. Glomerular volume fraction (Vv(glom/cortex)) was measured by means of a point-counting method, and mean glomerular volume (V(g)) was estimated by means of Weibel and Gomez (V(g)-W&G) and maximal profile area (V(g)-MPA) methods...
October 2003: Journal of the American Society of Nephrology: JASN
Didier Laurent, Kevin Poirier, James Wasvary, Markus Rudin
In this study, dynamic MRI was applied to investigate the effect of genetic hypertension on the renal clearance of Gd(DTPA). Assuming that the paramagnetic agent was essentially cleared through the kidney by glomerular filtration, a first-order kinetic model was used to estimate a rate constant k(cl) describing the transport from the renal cortex to the inner medulla. Experiments were carried out on 12-15-week-old spontaneously hypertensive rats (young-SHR) and age-matched Wistar-Kyoto rats (young-WKY). An additional group of 22-25-week-old SHR (old-SHR) was investigated to assess the long-term effect of chronic hypertension on kidney function...
January 2002: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
D M Corsi, L V Elst, R N Muller, H van Bekkum, J A Peters
Magnetic resonance angiography (MRA) has put forth an impetus for the development of macromolecular GdIII complexes that have a prolonged lifetime in the vascular system. Herein, we report the synthesis and GdIII complexation of a new sugar conjugate based on inulin and the DO3A ligand (DO3A = 1,4,7,10-tetraazacyclododecan-1,4,7-triacetic acid). Two API-DO3ASQ conjugates (API = O-(aminopropyl)inulin, SQ = squaric acid = 3,4-dihydroxy-3-cyclobutene-1,2-dione) with different degrees of substitution (ds = 0.7 and ds = 1...
January 5, 2001: Chemistry: a European Journal
S K Sarkar, R E Rycyna, R E Lenkinski, H A Solleveld, L B Kinter
We have developed a novel contrast agent, ytterbium-diethylenetriamine pentaacetic acid (Yb-DTPA), for magnetic resonance imaging (MRI) and its mechanism of action is predominantly by the susceptibility mechanism. We have applied this contrast agent for renal MRI studies. We also demonstrate that Yb-DTPA has a renal clearance similar to that of inulin in rats and may therefore be useful for the estimation of glomerular filtration rate.
February 1991: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
F E Armitage, D E Richardson, K C Li
The synthesis and characterization of polysaccharides esterified with gadolinium diethylenetriaminepentaacetic acid (GdDTPA) are described. The results of several synthetic methods are presented for esterification of dextrans and inulin with DTPA. One method results in highly conjugated products labeled with an average of 0.4 mol of GdDTPA/mol of glucopyranose unit in dextrans of up to 70,800 average molecular weight and 0.5 mol of GdDTPA/mol of fructofuranose unit in inulin. Chromatographic and potentiometric evidence supporting the absence of significant chelate cross-linking of the conjugated polysaccharides is presented...
November 1990: Bioconjugate Chemistry
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