bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relaxation enhancing properties of MnDPDP in human myocardium
Authors: Skjold Arne , Vangberg Torgil R , Kristoffersen Anders , Haraldseth Olav , Jynge Per , Larsson Henrik B.W. 
Published: November 2004

AbstractPurposeTo assess magnitude and duration of changes in myocardial longitudinal relaxation rate (R1) in humans following infusion of the manganese (Mn) releasing contrast agent MnDPDP (Mn‐dipyridoxyl‐diphosphate).Materials and MethodsFifteen healthy volunteers were divided into three groups. After initial myocardial and liver R1 measurements using an inversion recovery (IR) turbo fast low‐angle shot (FLASH) sequence at 1.5 Tesla, the groups were given different doses of intravenous MnDPDP: 5, 10 and 15 μmol/kg body weight, respectively, over 30 minutes. R1 measurements were then repeated at 1, 2, 4, 8, and 24 hours after the infusion ended.ResultsThe left ventricular wall R1 prevalue was 0.98 second−1 (±0.04). R1 increased on average (all 15 subjects) 0.41 second−1 (±0.09). The increase was present one hour after the end of the infusion, remained relatively constant the next two hours, and then declined gradually. After 24 hours, there was still a moderate R1 elevation present, with an average R1‐value of 1.16 (±0.05). There were only small differences in myocardial R1 responses between the three doses investigated, which was contrasted by a marked dose‐response in liver tissue.ConclusionMnDPDP gave a significant and prolonged rise in myocardial R1 even at a dose of 5 μmol/kg. The R1‐values in the myocardium did not increase linearly with higher doses. J. Magn. Reson. Imaging 2004;20:948–952. © 2004 Wiley‐Liss, Inc.
Near‐infrared fluorescence imaging and histology confirm anomalous edematous signal distribution detected in the rat lung by MRI after allergen challenge
Authors: Tigani Bruno , Gremlich Hans‐Ulrich , Cannet Catherine , Zurbruegg Stefan , Karmouty Quintana Harry , Beckmann Nicolau 
Published: November 2004

AbstractPurposeTo address the issue concerning the predominant location, on the left anatomic side, of edematous signals detected by magnetic resonance imaging (MRI) in the lungs of actively sensitized rats following intratracheal (IT) allergen challenge.Materials and MethodsNear‐infrared fluorescence (NIRF) imaging was used to detect the lobular distribution in the lungs of normal rats of an IT instilled fluorescent dye, Cy5.5. Actively sensitized Brown Norway rats were examined by MRI 24 hours after IT administration of ovalbumin. The perivascular edema was quantified by histology in the different lobes of lungs removed from the same animals immediately after the MRI acquisitions.ResultsAn uneven distribution of Cy5.5 was found, predominantly on the left lobe, paralleling the localized development of allergic pulmonary inflammation in the left lobe detected as edematous signal by MRI and confirmed by histology. The patterns of the distributions of the dye between and within the lobes were very similar to those of perivascular edema assessed histologically.ConclusionThe data indicate a relationship between the molecular deposition of the dye detected by NIRF in the lungs and the distribution of allergen eliciting the development of pulmonary inflammation in actively rats. The combination of MRI with NIRF imaging may provide important information in preclinical pharmacologic research in the area of airway diseases. While MRI is able to address the effects of compounds on the inflammatory response in models of airways diseases, NIRF imaging may provide important insights on drug distribution and interaction in the lung, being thus suited for molecular imaging studies. J. Magn. Reson. Imaging 2004;20:967–974. © 2004 Wiley‐Liss, Inc.
Quantitative cerebral perfusion using the PRESTO acquisition scheme
Authors: Pedersen Michael , Klarhöfer Markus , Christensen Søren , Ouallet Jean‐Christophe , Østergaard Leif , Dousset Vincent , Moonen Chrit 
Published: November 2004

AbstractPurposeTo evaluate the feasibility of using the rapid principles of echo shifting with a train of observations (PRESTO) sequence for measurements of cerebral hemodynamic parameters based on first pass of a contrast agent.Materials and MethodsSimulations were performed to investigate potential resolution loss due to relaxation effects. Experimental evaluation was conducted in healthy monkey brains using PRESTO and echo‐planar imaging (EPI).ResultsFor short echo trains, an insignificant contribution of the longitudinal and transversal relaxation rates to the signal amplitude in white matter and gray matter was found, whereas a contribution as large as 40% was found in large vessels. Simulations of the point spread function demonstrated that PRESTO, despite its shorter readout trains, only has a small advantage in terms of maintenance of image resolution during bolus passage compared to EPI as long as the EPI echo train can be kept similar to the T2* value at the top of the bolus. Experimental studies revealed that the PRESTO and EPI gray matter to white matter ratio were similar with respect to cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT).ConclusionThe study showed that PRESTO and EPI led to comparable quantitative perfusion parameters. J. Magn. Reson. Imaging 2004;20:930–940. © 2004 Wiley‐Liss, Inc.
Smooth muscle tumors of uncertain malignant potential and leiomyosarcomas of the uterus: MR findings
Authors: Tanaka Yumiko Oishi , Nishida Masato , Tsunoda Hajime , Okamoto Yoshikazu , Yoshikawa Hiroyuki 
Published: November 2004

AbstractPurposeTo study the MR characteristics of nonbenign uterine smooth muscle tumors.Materials and MethodsNine patients with pathologically proven leiomyosarcomas, and three patients with smooth muscle tumors of uncertain malignant potential (SMTUMP) were included in this study. Twelve cases of benign uterine leiomyomas and variants, in which gynecologists suspected leiomyosarcomas, were also analyzed. In each case we studied the size, location, signal intensity, and contrast enhancement of the tumors.ResultsNine of the 12 nonbenign characters had more than 50% of high‐intensity areas on T2‐weighted images (T2WI), and some hyperintense foci on T1‐weighted images (T1WI). In the contrast study, nine of 12 nonbenign characters had well‐demarcated unenhanced areas. On the other hand, only two of 12 benign characters showed such a signal intensity pattern, and none of them had a pocket‐like unenhanced area.ConclusionAlthough there were some exceptions, more than 50% of high signal on T2WI, and the presence of any small high‐signal areas on T1WI with unenhanced pockets were considered MR‐suggestive for SMTUMPs and leiomyosarcomas. J. Magn. Reson. Imaging 2004;20:998–1007. © 2004 Wiley‐Liss, Inc.
Three‐dimensional MR angiography in imaging platinum alloy stents
Authors: Trost David W. , Zhang Hong Lei , Prince Martin R. , Winchester Priscilla A. , Wang Yi , Watts Richard , Sos Thomas A. 
Published: November 2004

AbstractPurposeTo evaluate visualization inside platinum stents with three‐dimensional contrast‐enhanced magnetic resonance angiography (CE‐MRA).Materials and MethodsBreath‐hold three‐dimensional gadolinium (Gd) MRA was performed on 18 patients with 22 platinum stents in the renal (n = 18), celiac (n = 1), superior mesenteric (n = 1), and iliac (n = 2) arteries. Electronic calibers were used to measure the lumen diameter within the stent and just distal to the stent to calculate percent stenosis. MRA accuracy was determined from the difference between percent stenosis measured on MRA and digital subtracted angiography (DSA). The patients were imaged at flip angles of 45°, 60°, 75°, 90°, and 150°.ResultsMRA demonstrated the stent lumen in all of the patients, with a mean difference between MRA and DSA of 21%. For stents oriented parallel to B0 (iliac arteries) the difference was only 10%, as compared to 22% for stents perpendicular to B0. The flip angle with the best agreement between MRA and DSA was 75° (16%).ConclusionThe lumen of a platinum stent can be imaged with three‐dimensional CE‐MRA, although grading of restenosis has limited accuracy. The best results were obtained with a flip angle of 75° and for stents in the iliac arteries parallel to B0. J. Magn. Reson. Imaging 2004;20:975–980. © 2004 Wiley‐Liss, Inc.
Muscle kinematics during isometric contraction: Development of phase contrast and spin tag techniques to study healthy and atrophied muscles
Authors: Sinha Shantanu , Hodgson John A. , Finni Taija , Lai Alex M. , Grinstead John , Edgerton V. Reggie 
Published: November 2004

AbstractPurposeTo develop and compare phase‐contrast (PC) and spin‐tag (ST) MR imaging techniques for accurate quantification of velocity and displacement distribution in the muscle tendon complex of the lower leg during isometric contractions under in vivo conditions, in healthy subjects and subjects with atrophy.Materials and MethodsTechniques were developed to acquire PC and ST dynamic images, gated to the force exerted by a subject during isometric contraction. Algorithms were optimized for correction of phase shading errors. Flow velocity quantification was validated in phantoms and ex vivo rabbit muscles. Trajectories of pixels calculated from PC images were compared with those in ST images. Velocity distributions were determined in healthy muscles, those atrophied by four weeks of suspension, and during physiotherapy‐induced recovery.ResultsThe technique developed allowed acquisition of images retrospectively gated to the isometric contraction performed with the subject in the scanner. Significant phase shading errors in PC images (≈3 cm/second over the field of view) were reduced to the background noise level by the correction algorithm. Tissue trajectories calculated from PC images agreed very well with those from ST images both in human and excised animal tissues. Peak velocities in atrophied muscles were significantly lower compared to the preatrophy state but recovered to baseline values after six weeks of therapy.ConclusionWe show the feasibility of monitoring muscle velocity and tissue displacement during voluntary contractions in humans under in vivo conditions using MR tissue motion mapping methods. The clinical feasibility of this technique in monitoring atrophied muscle is also demonstrated. J. Magn. Reson. Imaging 2004;20:1008–1019. © 2004 Wiley‐Liss, Inc.
High‐resolution, multicontrast three‐dimensional‐MRI characterizes atherosclerotic plaque composition in ApoE–/– mice ex vivo
Authors: Schneider Jürgen E. , McAteer Martina A. , Tyler Damian J. , Clarke Kieran , Channon Keith M. , Choudhury Robin P. , Neubauer Stefan 
Published: November 2004

AbstractPurposeTo systematically investigate intrinsic MR contrast mechanisms that would facilitate plaque characterization and quantification in the aortic root and brachiocephalic artery of ApoE–/– mice ex vivo.Materials and MethodsTo establish unambiguous MR parameters for routinely analyzing atherosclerotic plaque ex vivo at 11.7 T, relaxation times of plaque components were quantitatively assessed. Magnetization transfer and lipid‐proton three‐dimensional MR imaging was investigated for visualization of collagen‐ and lipid‐rich plaque regions, respectively. A three‐dimensional multiecho sequence with a spatial resolution of 47 × 47 × 63 μm was implemented providing a variable degree of T2‐weighting.ResultsRelaxation time measurements showed clear tissue heterogeneity between atherosclerotic plaque components in the T2‐values, but similar T1‐values at 11.7 T (T1/T2 mean ± SD; cellular plaque component: 1.2 ± 0.3 seconds/26.3 ± 0.4 msec; fibrofatty plaque component: 1.1 ± 0.2 seconds/13.7 ± 2.0 msec). The three‐dimensional multiecho sequence allowed the calculation of the intrinsic proton density and T2‐maps. The sum of the multiecho data provided strong T2‐weighting that facilitated quantification of various components of atherosclerotic plaque in the mouse aortic root and correlated well with histology (P < 0.0001).ConclusionHigh‐resolution MRI allows for accurate classification and quantification of atherosclerotic plaque components in the aortic root of mice. J. Magn. Reson. Imaging 2004;20:981–989. © 2004 Wiley‐Liss, Inc.
Neurochemistry of late‐life major depression: A pilot two‐dimensional MR spectroscopic study
Authors: Binesh Nader , Kumar Anand , Hwang Sun , Mintz Jim , Thomas M. Albert 
Published: November 2004

AbstractPurposeTo evaluate a two‐dimensional localized chemical shift correlated spectroscopy (L‐COSY) sequence in elderly patients with major depression.Materials and MethodsA total of 33 healthy elderly subjects and 15 elderly patients with major depression were investigated. A voxel size of 3 × 3 × 3 cm3 was chosen in the dorsolateral prefrontal region with predominantly white matter, with the use of three slice‐selective radiofrequency (RF) pulses (90°, 180°, and 90°). A chemical shift‐selective (CHESS) sequence was used prior to volume localization for the presaturation of water. The two‐dimensional raw data matrix consisted of 1024 complex points along the detection period (t2), and 100 increments along the evolution period (t1), resulting in a total acquisition time of approximately 27 minutes per acquisition. The metabolite ratios were calculated using the two‐dimensional peak volumes with respect to the diagonal peak volume of total creatine (Cr) at 3.0 ppm.ResultsIn the 33 elderly subjects, the mean ratio of choline (Cho) to Cr was 10% higher in men compared to women (P < 0.05), consistent with earlier findings obtained by one‐dimensional MRS. When the metabolite ratios were compared in a subsample of 16 elderly female controls and 12 depressed female patients, the depressed geriatric patients had higher levels of myoinositol (mI), phosphoethanolamine (PE), and glutamate/glutamine (Glx) than the controls, although the differences were not statistically significant.ConclusionOur pilot study shows the feasibility of performing two‐dimensional L‐COSY successfully in elderly subjects and patients with late‐life mood disorders. These findings are consistent with and expand on our earlier findings in major depressive disorder (MDD) detected with one‐dimensional MRS. J. Magn. Reson. Imaging 2004;20:1039–1045. © 2004 Wiley‐Liss, Inc.
Nitrate stability in loess soils under anaerobic conditions—laboratory studies
Authors: Włodarczyk Teresa , Stępniewski Witold , Brzezińska Małgorzata , Stępniewska Zofia 
Published: November 2004

AbstractThe objective of this laboratory study with six loess soils (three Eutric CambisoIs and three Haplic Phaeozems) incubated under flooded conditions was to examine the effect of a wide range of NO$ _3^- $ doses under anaerobic conditions on soil redox potential and N2O emission or absorption. Due to the fact that loess soils are usually well‐drained and are expected to be absorbers during prevailing part of the season, the study aimed at determination of the conditions decisive for the transition from emission to absorption process. On the basis of the response to soil nitrate level, the two groups of soils were distinguished with high and low denitrification capacity. The soil denitrification activity showed Michaelis‐Menten kinetics with respect to soil nitrate content with KM in the range 50–100 mg NO$ _3^- $‐N kg–1. Percentage of nitrates converted to N2O increased linearly with nitrate concentration in the range from 25 to 100 mg NO$ _3^- $‐N kg–1 up to 43% and decreased linearly at higher concentrations reaching practically zero at concentrations about 600 mg NO$ _3^- $‐N kg–1. No denitrification was observed below 25 mg NO$ _3^- $‐N kg–1. Nitrous oxide absorption in soil occurred only at nitrate concentrations to 100 mg NO$ _3^- $‐N kg–1 and in this concentration range was proportional to the denitrification rate. Nitrous oxide was formed at redox potentials below +200 mV and started to disappear at negative Eh values.
Limits imposed by salt to the growth of the halophyte Sesuvium portulacastrum
Authors: Messedi Dorsaf , Labidi Nehla , Grignon Claude , Abdelly Chedly 
Published: November 2004

AbstractThe growth of the halophyte Sesuvium portulacastrum, commonly known as sea purslane, is impeded by NaCl only at high (600–1000 mM) concentration. Therefore, the goal of this investigation was to identify the mechanisms which set the limit of the salt resistance of S. portulacastrum. 21‐day‐old cuttings were grown for 45–50 d under split‐root conditions in which one half of the root system was immersed in complete nutrient solution supplemented with 800 mM NaCl, while the other half was immersed in a NaCl‐free medium, containing all nutrients or being deprived of potassium or calcium or nitrogen. Using this approach, we demonstrate that K+ and N uptake was impaired in roots exposed to NaCl. Concerning Ca2+, there was no indication of uptake inhibition by NaCl. However, restriction of K+ uptake by roots was compensated by an increase in the K+‐use efficiency, so that growth was not inhibited. Concerning N, our analysis shows that NO$ _3^- $ and/or NH$ _4^+ $ uptake, but not their assimilation, was limited by salt treatment. Thus, we conclude that at high salinity levels, the growth of S. portulacastrum is limited by the restrictions imposed by NaCl on N uptake, perhaps in addition to inhibiting effects of excessive Na+ accumulation in shoot.
Reaktion der Zuckerrübe (Beta vulgaris var. altissima) auf die Kaliumdüngung – ein 20‐jähriger Feldversuch
Authors: Römer Wilhelm , Claassen Norbert , Steingrobe Bernd , Märländer Bernward 
Published: November 2004

AbstractDie Untersuchungen hatten das Ziel, in einer Zuckerrrüben‐Weizen‐Gerste‐Fruchtfolge auf einem Auenboden (toniger Schluff) in Südniedersachsen eine K‐Düngungsstrategie für hohe und stabile Erträge (hier fokussiert auf die bereinigten Zuckererträge = BZE) zu erarbeiten. Hierzu gab es, bei generellem Verbleib von Stroh und Rübenblatt auf dem Feld, seit 1983 folgende Kalium‐Düngungsvarianten: 1) jährliche K‐Zufuhr in Höhe des 0‐, 0,5‐, 1‐, 1,5‐, 3‐ und 9fachen Ersatzes der einfachen mittleren jährlichen K‐Abfuhr (0, 29, 58, 87, 174 bzw. 524 kg K ha–1 a–1), wobei die Parzellen mit dem 3‐ bzw. 9fachen Ersatz seit 1995 nur noch je 174 kg K ha–1 alle 3 Jahre erhielten (Fruchtfolge‐Düngung); 2) die jährliche K‐Gabe (58 kg K ha–1) mit einer 3‐jährlichen K‐Gabe (174 kg K ha–1); 3) die jährliche K‐Gabe (87 kg K ha–1) als Applikation im Herbst oder Frühjahr; 4) die jährliche K‐Gabe in mineralischer oder in „organischer”︁ Form als Ganzpflanzenrecycling (Korn plus Stroh, Rüben plus Blatt) und 5) die Applikation einer zusätzlichen NaCl‐Gabe (29 kg ha–1) zur einfachen K‐Gabe (58 kg ha–1) vor den Zuckerrüben.Die Rübenerträge stiegen bis zur höchsten K‐Gabe an, bei gleichzeitigem Anstieg der lactatlöslichen Boden‐K‐Gehalte. Die bereinigten Zuckergehalte erreichten bei einer jährlichen K‐Gabe von 174 kg K ha–1 ihr Maximum. Der BZE stieg im Mittel aller Versuchsjahre bis zur höchsten jährlichen K‐Gabe an. Es gab keinen Unterschied in der K‐Düngewirkung in Bezug auf den BZE zwischen Herbst‐ und Frühjahrsdüngung. Kalium aus Mineraldünger und organischem Material hatte ähnliche Wirksamkeit. Eine zusätzliche NaCl‐Gabe erhöhte den BZE nur in einzelnen Jahren um wenige Prozentpunkte. Als ökonomisch empfehlenswert ergab sich eine K‐Fruchtfolgedüngung vor den Zuckerrüben in Höhe von 174 kg K ha–1. Mit niedrigprozentigen Kali‐Salzen kann der NaCl‐Effekt nutzbar gemacht werden. Der lactatlösliche K‐Gehalt im Grenzbereich der Gehaltsklassen B/C (ca. 110 mg K (kg Boden)–1) ist für den geprüften Standort ausreichend für hohe BZE.
Depletion of non‐exchangeable NH$ _4^+ $ at the root–soil and hyphae–soil interface of VA mycorrhizal maize (Zea mays) and parsley (Petroselinum sativum)
Authors: Scherer Heinrich W. , Frost Maren 
Published: November 2004

AbstractMobilization of non‐exchangeable ammonium (NH$ _4^+ $) by hyphae of the vesicular‐arbuscular mycorrhizal (VAM) fungus Glumus mosseae was studied under controlled experimental conditions. Maize (Zea mays) and parsley (Petroselinum sativum) were grown either alone or in symbiosis with Glomus mosseae in containers with separated compartments for roots and hyphal growth. In one experiment, 15NH$ _4^+ $ was added to the soil to differentiate between the native non‐exchangeable NH$ _4^+ $ and the non‐exchangeable NH$ _4^+ $ derived from N fertilization. Non‐exchangeable NH$ _4^+ $ was mobilized by plant growth. Plant dry weight and N uptake, however, were not significantly influenced by mycorrhizal colonization of the roots. The influence of root infection with mycorrhizal fungus on the mobilization of non‐exchangeable NH$ _4^+ $ was negligible. In the hyphal compartment, hyphal uptake of N resulted in a decrease of NH$ _4^+ $ in the soil solution and of exchangeable NH$ _4^+ $. However, the NH$ _4^+ $ concentration was still too high to permit the release of non‐exchangeable NH$ _4^+ $. The results demonstrate that, in contrast to roots, hyphae of VAM fungi are not able to form a non‐exchangeable‐NH$ _4^+ $ depletion zone in the adjacent soil. However, under conditions of a more substantial depletion of the exchangeable NH$ _4^+ $ in the mycorrhizal sphere (e.g., with longer growth), an effect of mycorrhiza on the non‐exchangeable NH$ _4^+ $ might be found.
Application of ground‐penetrating radar to determine the thickness of Pleistocene periglacial slope deposits
Authors: Sauer Daniela , Felix‐Henningsen Peter 
Published: November 2004

AbstractWide areas of the mountainous regions of Germany have rock covered by Pleistocene periglacial slope deposits (PPSD), formed by gelifluction during the cold periods of the ice ages in non‐glaciated areas. The PPSD provide the parent material for soil development, and their physical characteristics affect several stabile soil properties. Because the PPSD play a significant ecological role, we studied the spatial distribution and properties of the PPSD in order to assess the distribution of the stabile soil properties. The high stone content of the PPSD greatly hinders augering and digging. Hence, we tested the use of ground‐penetrating radar (GPR) as a potentially time‐saving, non‐destructive method to determine the thickness of the PPSD. In several study areas of the Rhenish Massif, GPR investigations of single soil profiles and soil transects along an exposed gas‐pipeline ditch were carried out. The GPR images were compared to the actual thickness of the layers of the PPSD exposed in the profiles and the ditch. In the GPR images usually at least one distinct boundary could be identified, which occurs at the transition between the loose material and the hard rock, mostly ranging between 50 and 150 cm depth. In some cases, in which stone content changed abruptly between different layers of the PPSD, also the boundaries between these layers could be identified in the GPR image. On the other hand, in areas where remnants of the Mesozoic‐Tertiary weathering mantle are preserved, the boundary between the saprolite and the overlying basal layer of the PPSD is ambiguous or not at all visible.