bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuropathy‐induced apoptosis: Protective effect of physostigmine
Authors: Di Cesare Mannelli L. , Bartolini A. , Ghelardini C. 
Published: January 2009

AbstractTraumatic, infectious, metabolic, and chemical noxa to the nervous system are the etiology of a crippling disease generally termed neuropathy. Motor disorders, altered sensibility, and pain are the pathognomonic traits. Cellular alterations induced by this chronic pathology include mitochondrial dysfunctions that lead to the activation of the apoptotic cascade. Energy imbalance can compromise the maintenance of mitochondrial membrane potential, furthering the release of cytochrome C and the subsequent cleavage and activation of caspases. Chronic constriction injury (CCI) of the rat sciatic nerve is a neuropathy model able to induce a strong mitochondrial impairment with a consequent apoptotic induction. In this model, the acetylcholinesterase inhibitor physostigmine is administered at 0.125 mg/kg i.p. (twice per day) starting from the operation and for 15 days after. The cholinergic activation reduces cytosolic levels of cytochrome C, suggesting an improved stability of the mitochondrial membrane, and the expression level of the active caspase 3 fragments (19, 16 kDa) is reduced significantly with respect to saline treatment. Accordingly, physostigmine impairs caspase 3 protease activity. In fact, the target of the activated caspase 3, the 89‐kDa PARP fragment, is significantly less expressed in the ligated nerve of physostigmine‐treated rats, reaching levels that are comparable to those in the contralateral unligated nerve. Finally, this natural acetylcholinesterase inhibitor reduces DNA fragmentation both in the proximal and in the distal parts of the nerve. This protection correlates with the induction of XIAP. Therefore, apoptosis, central to tissue degeneration, is prevented by repeated physostigmine treatment of CCI animals. © 2009 Wiley‐Liss, Inc.
Recombinant human platelet‐derived growth factor BB (rhPDGF‐BB) and beta‐tricalcium phosphate/collagen matrix enhance fracture healing in a diabetic rat model
Authors: Al‐Zube Loay , Breitbart Eric A. , O'Connor J. Patrick , Parsons J. Russell , Bradica Gino , Hart Charles E. , Lin Sheldon S. 
Published: January 2009

AbstractDiabetes mellitus is a common systemic disease that has been associated with poor fracture healing outcomes. The mechanism through which diabetes impairs bone regeneration is unknown. One possible mechanism may be related to either decreased or uncoordinated release of local growth factors at the fracture site. Indeed, previous studies have found reduced platelet‐derived growth factor (PDGF) levels in the fracture callus of diabetic rats, suggesting that local application of PDGF may overcome the negative effects of diabetes and promote fracture healing. To test this hypothesis, low (22 µg) and high (75 ug) doses of recombinant human PDGF‐BB (rhPDGF‐BB) were applied directly to femur fracture sites in BB Wistar diabetic rats that were then compared to untreated or vehicle‐treated animals. rhPDGF‐BB treatment significantly increased early callus cell proliferation compared to that in control specimens. Low dose rhPDGF‐BB treatment significantly increased callus peak torque values (p < 0.05) at 8 weeks after fracture as compared to controls. High dose rhPDGF‐BB treatment increased callus bone area at 12 weeks postfracture. These data indicate that rhPDGF‐BB treatment ameliorates the effects of diabetes on fracture healing by promoting early cellular proliferation that ultimately leads to more bone formation. Local application of rhPDGF‐BB may be a new therapeutic approach to treat diabetes‐impaired fracture healing. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 1074–1081, 2009
Lymph node assessment and lymphadenectomy in prostate cancer
Authors: Ordon Michael , Nam Robert K. 
Published: January 2009

AbstractThe role of lymph node assessment for patients with clinically localized prostate cancer has significantly evolved over the last 20 years. The status of pelvic lymph nodes primarily served as a prognostic marker for prostate cancer. Improved methods in assessing the risk for cancer progression and metastasis have enhanced our ability to identify patients who require pelvic lymphadenectomy during radical prostatectomy. The status of pelvic lymph nodes is also being used to guide further treatments after surgery. Also, recent data has shown possible therapeutic benefit of lymphadenectomy in improving cancer specific survival. J. Surg. Oncol. 2009;99:215–224. © 2009 Wiley‐Liss, Inc.
Electrodynamic constraints on homogeneity and radiofrequency power deposition in multiple coil excitations
Authors: Lattanzi Riccardo , Sodickson Daniel K. , Grant Aaron K. , Zhu Yudong 
Published: January 2009

AbstractThe promise of increased signal‐to‐noise ratio and spatial/spectral resolution continues to drive MR technology toward higher magnetic field strengths. SAR management and B1 inhomogeneity correction become critical issues at the high frequencies associated with high field MR. In recent years, multiple coil excitation techniques have been recognized as potentially powerful tools for controlling specific absorption rate (SAR) while simultaneously compensating for B1 inhomogeneities. This work explores electrodynamic constraints on transmit homogeneity and SAR, for both fully parallel transmission and its time‐independent special case known as radiofrequency shimming. Ultimate intrinsic SAR—the lowest possible SAR consistent with electrodynamics for a particular excitation profile but independent of transmit coil design—is studied for different field strengths, object sizes, and pulse acceleration factors. The approach to the ultimate intrinsic limit with increasing numbers of finite transmit coils is also studied, and the tradeoff between homogeneity and SAR is explored for various excitation strategies. In the case of fully parallel transmission, ultimate intrinsic SAR shows flattening or slight reduction with increasing field strength, in contradiction to the traditionally cited quadratic dependency, but consistent with established electrodynamic principles. Magn Reson Med 61:315–334, 2009. © 2009 Wiley‐Liss, Inc.
Comparison of gradient encoding directions for higher order tensor diffusion data
Authors: Mang Sarah C. , Gembris Daniel , Grodd Wolfgang , Klose Uwe 
Published: January 2009

AbstractRecently, higher order tensors were proposed for a more advanced representation of non‐Gaussian diffusion. These advanced diffusion models have new requirements for the gradient encoding schemes used in the diffusion weighted image acquisition. The influence of the gradient encoding schemes on the estimated standard second order diffusion tensor was previously investigated. Here, we focus on the suitability of different encoding scheme types for higher order tensor models. Two quality measures for the gradient encoding schemes, the condition number of the estimation matrix and a new measure that evaluates the signal deviation on simulated data, are used to determine which gradient encoding is suited best for higher order tensor estimations. Six different gradient encoding scheme types were investigated. A certain force‐minimizing scheme type gave the best results in the evaluations presented here. Magn Reson Med 61:335–343, 2009. © 2009 Wiley‐Liss, Inc.
Effect of inflow of fresh blood on vascular‐space‐occupancy (VASO) contrast
Authors: Donahue Manus J. , Hua Jun , Pekar James J. , van Zijl Peter C.M. 
Published: January 2009

AbstractIn vascular‐space‐occupancy (VASO)‐MRI, cerebral blood volume (CBV)‐weighted contrast is generated by applying a nonselective inversion pulse followed by imaging when blood water magnetization is zero. An uncertainty in VASO relates to the completeness of blood water nulling. Specifically, radio frequency (RF) coils produce a finite inversion volume, rendering the possibility of fresh, non‐nulled blood. Here, VASO‐functional MRI (fMRI) was performed for varying inversion volume and TR using body coil RF transmission. For thin inversion volume thickness (δtot < 10 mm), VASO signal changes were positive (ΔS/S = 2.1–2.6%). Signal changes were negative and varied in magnitude for intermediate inversion volumes (δtot = 100–300 mm), yet did not differ significantly (P > 0.05) for δtot > 300 mm. These data suggest that blood water is in steady state for δtot > 300 mm. In this appropriate range, long‐TR VASO data converged to a less negative value (ΔS/S = –1.4% ± 0.2%) than short‐TR data (ΔS/S = –2.2% ± 0.2%), implying that cerebral blood flow or transit‐state effects may influence VASO contrast at short TR. Magn Reson Med 61:473–480, 2009. © 2009 Wiley‐Liss, Inc.
Intra‐thoracic blood volume measurement by contrast magnetic resonance imaging
Authors: Mischi M. , van den Bosch H.C.M. , den Boer J.A. , Verwoerd J. , Grouls R.J.E. , Peels C.H. , Korsten H.H.M. 
Published: January 2009

AbstractThe intra‐thoracic blood volume (ITBV) is a cardiovascular parameter related to the cardiac preload and left ventricular function. Its assessment is, therefore, important for diagnosis and follow‐up of several cardiovascular dysfunctions. Nowadays, the ITBV can be accurately measured only by invasive indicator dilution techniques, which require a double catheterization of the patient. In this study, a novel technique is presented for ITBV assessment by dynamic magnetic resonance imaging after intravenous injection of a small bolus of gadolinium chelate. The dose was chosen on the basis of in vitro calibration. The bolus first pass is detected from a simultaneous dynamic image series of the right and left ventricles. Two indicator dilution curves are derived and used to inspect the transpulmonary dilution system. Various mathematical models for the interpretation of the measured indicator dilution curves are compared. The ITBV is assessed as the product of the transpulmonary mean transit time of the indicator and the cardiac output, obtained by phase contrast magnetic resonance angiography. In vitro measurements showed a correlation coefficient larger than 0.99 and preliminary tests with volunteers proved the feasibility of the method, opening new possibilities for noninvasive quantitative cardiovascular diagnostics. Magn Reson Med 61:344–353, 2009. © 2009 Wiley‐Liss, Inc.
Selective resonance suppression 1H‐[13C] NMR spectroscopy with asymmetric adiabatic RF pulses
Authors: Xin Lijing , Frenkel Hanne , Mlynárik Vladimír , Morgenthaler Florence D. , Gruetter Rolf 
Published: January 2009

AbstractDespite obvious improvements in spectral resolution at high magnetic field, the detection of 13C labeling by 1H‐[13C] NMR spectroscopy remains hampered by spectral overlap, such as in the spectral region of 1H resonances bound to C3 of glutamate (Glu) and glutamine (Gln), and C6 of N‐acetylaspartate (NAA). The aim of this study was to develop, implement, and apply a novel 1H‐[13C] NMR spectroscopic editing scheme, dubbed “selective Resonance suppression by Adiabatic Carbon Editing and Decoupling single‐voxel STimulated Echo Acquisition Mode” (RACED‐STEAM). The sequence is based on the application of two asymmetric narrow‐transition‐band adiabatic RF inversion pulses at the resonance frequency of the 13C coupled to the protons that need to be suppressed during the mixing time (TM) period, alternating the inversion band downfield and upfield from the 13C resonance on odd and even scans, respectively, thus suppressing the detection of 1H resonances bound to 13C within the transition band of the inversion pulse. The results demonstrate the efficient suppression of 1H resonances bound to C3 of Glu and Gln, and C4 of Glu, which allows the 1H resonances bound to C6 of NAA and C4 of Gln to be revealed. The measured time course of the resolved labeling into NAA C6 with the new scheme was consistent with the slow turnover of NAA. Magn Reson Med 61:260–266, 2009. © 2009 Wiley‐Liss, Inc.
Use of magnetic nanoparticles to monitor alginate‐encapsulated βTC‐tet cells
Authors: Constantinidis Ioannis , Grant Samuel C. , Simpson Nicholas E. , Oca‐Cossio Jose A. , Sweeney Carol A. , Mao Hui , Blackband Stephen J. , Sambanis Athanassios 
Published: January 2009

AbstractNoninvasive monitoring of tissue‐engineered constructs is an important component in optimizing construct design and assessing therapeutic efficacy. In recent years, cellular and molecular imaging initiatives have spurred the use of iron oxide‐based contrast agents in the field of NMR imaging. Although their use in medical research has been widespread, their application in tissue engineering has been limited. In this study, the utility of monocrystalline iron oxide nanoparticles (MIONs) as an NMR contrast agent was evaluated for βTC‐tet cells encapsulated within alginate/poly‐L‐lysine/alginate (APA) microbeads. The constructs were labeled with MIONs in two different ways: 1) MION‐labeled βTC‐tet cells were encapsulated in APA beads (i.e., intracellular compartment), and 2) MION particles were suspended in the alginate solution prior to encapsulation so that the alginate matrix was labeled with MIONs instead of the cells (i.e., extracellular compartment). The data show that although the location of cells can be identified within APA beads, cell growth or rearrangement within these constructs cannot be effectively monitored, regardless of the location of MION compartmentalization. The advantages and disadvantages of these techniques and their potential use in tissue engineering are discussed. Magn Reson Med 61:282–290, 2009. © 2009 Wiley‐Liss, Inc.
Temporal stability of adaptive 3D radial MRI using multidimensional golden means
Authors: Chan Rachel W. , Ramsay Elizabeth A. , Cunningham Charles H. , Plewes Donald B. 
Published: January 2009

AbstractBreast tumor diagnosis requires both high spatial resolution to obtain information about tumor morphology and high temporal resolution to probe the kinetics of contrast uptake. Adaptive sampling of k‐space allows images in dynamic contrast‐enhanced (DCE)‐magnetic resonance imaging (MRI) to be reconstructed at various spatial or temporal resolutions from the same dataset. However, conventional radial approaches have limited flexibility that restricts image reconstruction to predetermined resolutions. Golden‐angle radial k‐space sampling achieves flexibility in‐plane with samples that are incremented by the golden angle, which fills two‐dimensional (2D) k‐space with radial spokes that have a relatively uniform angular distribution for any time interval. We extend this method to three‐dimensional (3D) radial sampling, or 3D‐Projection Reconstruction (3D‐PR) using multidimensional golden means, which are derived from modified Fibonacci sequences by an eigenvalue approach. We quantitatively compare this technique to conventional 3D radial methods in terms of the fluctuation in error caused by undersampling artifacts, and show that the golden 3D‐PR method can substantially improve the temporal stability of quantitative measurements made from dynamic images when compared to conventional 3D radial approaches of k‐space sampling. Magn Reson Med 61:354–363, 2009. © 2009 Wiley‐Liss, Inc.
Reduced power magnetic resonance spectroscopic imaging of the prostate at 4.0 Tesla
Authors: Near Jamie , Romagnoli Cesare , Bartha Robert 
Published: January 2009

AbstractProton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been described at 1.5 T and 3 T as a means of localizing prostate cancers with high sensitivity and specificity. This technique could be improved by increasing the field strength further; however, it has not been described in detail above 3 T. To address the increase in B1 and SAR at high field strengths, a new protocol is described for reduced power STEAM MRSI of the prostate at 4.0 Tesla, using a pelvic surface coil array for RF transmission and reception, and a solid, reusable endorectal coil for reception only. The optimal STEAM sequence timing parameters for observation of the strongly coupled citrate spin system were determined through simulation to be echo time (TE) = 27 ms and mixing time (TM) = 27 ms, and the results were verified in vitro. Power reduction was achieved by applying the VERSE method to each of the three slice selective pulses in the STEAM sequence, and the B1max and SAR were reduced by 43% and 36%, respectively. Finally, in vivo spectroscopic imaging data were acquired from a prostate cancer patient, demonstrating the detection of citrate, choline, and creatine with 0.37 cc nominal resolution in a 10 minute scan. Magn Reson Med 61:273–281, 2009. © 2009 Wiley‐Liss, Inc.
Whole‐brain single‐shot STEAM DTI at 4 Tesla utilizing transverse coherences for enhanced SNR
Authors: Stöcker Tony , Kaffanke Joachim , Shah N. Jon 
Published: January 2009

AbstractDiffusion tensor imaging is an important method for noninvasively acquiring structural information of the human brain. For advanced fiber tracking, the acquisition of diffusion‐weighted (DW) images has to be performed along many different spatial directions, resulting in long scan times. Therefore, the ultra‐fast imaging method, echo‐planar imaging (EPI), is mostly used, but this technique suffers from susceptibility‐induced image artefacts and geometric distortions. These problems become even more pronounced at very high magnetic field strengths. In this regard, DW, single‐shot STEAM is an interesting and rapid imaging alternative to EPI‐based methods. DW single‐shot STEAM enables the acquisition of artefact‐free images albeit at the expense of a reduced signal‐to‐noise ratio (SNR), which can be compensated by utilizing high magnetic fields. Here, the application of DW single‐shot STEAM at 4 Tesla is demonstrated. To optimize the SNR and the resolution properties, a new variable flip‐angle computational algorithm is introduced enabling accurate signal evolution computation with a precise calculation of transverse coherences. Omission of radiofrequency (RF) spoiling results in an approximate twofold increase of the DW signal by integration of the stable refocused transverse magnetization. The advantage of the approach is shown in simulations and in vivo experiments. Magn Reson Med 61:372–380, 2009. © 2009 Wiley‐Liss, Inc.
Comparison of hypercapnia‐based calibration techniques for measurement of cerebral oxygen metabolism with MRI
Authors: Bulte Daniel P. , Drescher Knut , Jezzard Peter 
Published: January 2009

AbstractMRI may be used to measure fractional changes in cerebral oxygen metabolism via a metabolic model. One step commonly used in this measurement is calibration with image data acquired during hypercapnia, which is a state of increased CO2 content of the blood. In this study some commonly used hypercapnia‐inducing stimuli were compared to assess their suitability for the calibration step. The following stimuli were investigated: (a) inspiration of a mixture of 4% CO2, 21% O2 and balance N2; (b) 30‐s breath holding; and (c) inspiration of a mixture of 4% CO2 and 96% O2 (i.e., carbogen). Measurements of BOLD and cerebral blood flow made on nine subjects during the different hypercapnia‐inducing stimuli showed that each stimulus leads to a different calibration of the model. We argue that of the aforementioned stimuli, inspiration of 4% CO2, 21% O2 and balance N2 should be preferred for the calibration as the other stimuli produce responses that violate assumptions of the metabolic model. Magn Reson Med 61:391–398, 2009. © 2009 Wiley‐Liss, Inc.
Advanced Lung Disease: Quality of Life and Role of Palliative Care
Authors: Gilbert Christopher R. , Smith Cecilia M. 
Published: January 2009

AbstractAdvanced restrictive lung diseases remain a challenge for both the clinician and patient alike. Because there are few available treatment options that prolong survival for patients with diseases such as idiopathic pulmonary fibrosis, improvement in quality of life and palliation of significant symptoms become realistic treatment goals. Several validated instruments that assess quality of life and health‐related quality of life have demonstrated the dramatic impact that lung disease has on patients. Quality‐of‐life assessments of patients with interstitial lung disease have commonly cited respiratory complaints as problematic, but other distressing symptoms often not addressed include fear, social isolation, anxiety, and depression. Not only do respiratory symptoms limit this patient population, but the awareness of decreased independence and ability for social participation also has an impact on the quality of life. Some patients describe a deepened spiritual well‐being during their disease process; however, many patients' mental health suffers with experiences of fear, worry, anxiety, and panic. Many patients express desire for more attention to end‐of‐life issues from their physicians. Fears of worsening symptoms and suffocation exist with an expressed desire by most to die peacefully with symptom control. Interventions to improve quality of life are largely directed at symptom control. Pharmacologic and nonpharmacologic interventions have been helpful in relieving dyspnea. Studies have demonstrated that the use of supplemental oxygen in the face of advancing hypoxemia can have both positive and negative effects on quality of life. Patients using nasal prongs describe feelings of self‐consciousness, embarrassment, and social withdrawal. Pulmonary rehabilitation is recommended, with some studies noting increased quality‐of‐life scores and decreased sensations of dyspnea. Sleep deprivation and poor sleep quality also have a negative impact on quality of life. Recognition and correction of nocturnal hypoxemia and other sleep disturbances should enhance quality of life in patients with restrictive lung disease; however, there is currently no evidence to support this claim. End‐of‐life care needs more attention by clinicians in the decision‐making and preparatory phase. Physicians need to maintain their focus on quality‐of‐life issues as medical management shifts from curative therapies to comfort management therapies. Palliative care and hospice appear to be underused in patients with advanced diseases other than cancer. Because the only curative option for some end‐stage restrictive lung diseases is lung transplantation, if transplantation is not an option, palliation of symptoms and hospice care may offer patients and families the opportunity to die with dignity and comfort. Mt Sinai J Med 76:63–70, © 2009 Mount Sinai School of Medicine
A mesoscopic model for the behaviour of concrete under high confinement
Authors: Dupray F. , Malecot Y. , Daudeville L. , Buzaud E. 
Published: January 2009

AbstractWhen impact loaded, concrete is submitted to high triaxial stresses. The experimental response of concrete under quasi‐static triaxial compression is studied using a triaxial press capable of applying a mean pressure greater than 1 GPa on cylindrical samples measuring 7 cm in diameter and 14 cm high. A numerical analysis of these previous experiments is performed herein at a mesoscopic scale. Concrete is modelled as a biphasic material consisting of a mortar (cement paste and fine aggregates) and roughly spherical aggregates (with a diameter exceeding 2 mm) whose characteristics are applied on a regular cubic finite element mesh. A damage‐plasticity model is then used to model the behaviour of mortar. An identification of model parameters on mortar samples and the subsequent comparison between numerical and experimental tests will be presented for hydrostatic and triaxial compression. Copyright © 2009 John Wiley & Sons, Ltd.