bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental measurements and multiphase flow models in solid SiC foam beds
Authors: Edouard David , Lacroix Maxime , Pham Charlotte , Mbodji Mamadou , Pham‐Huu Cuong
Published: September 2008

Solid foam matrices have been recently introduced and present a highly permeable porous structure with a high porosity (0.60–0.95), which enables a considerably reduction of the pressure drops along the catalyst bed even with a high specific surface area. It appears today that despite the hydrodynamics of trickle‐bed reactors operating with conventional packings (spheres, extrudates, monoliths, etc.) has become largely documented in the recent literature, trickle‐bed hydrodynamic behaviour with solid foam packings, on the contrary, largely remains terra incognita. In this context, two phases flows (air–water) in solid foams under cocurrent trickle flow conditions were analyzed in a fixed‐bed at ambient conditions. From Residence Time Distribution (RTD) curves, a new set of experimental data based on the hydrodynamics parameters (pressure drop and liquid holdup) of solid foams are presented. A model based on a cubic lattice approach developed in previous work is used to calculate the equivalent diameter for solid foam packings. Finally, through the modified Eötvös number and the relative permeability concept, the two‐phase pressure drop and liquid holdup are well estimated. These news results are important parameters for the design of new process in trickle flow conditions with solid foam packing. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Antagonism of the human epidermal growth factor receptor family controls disease severity in murine collagen‐induced arthritis
Authors: Sumariwalla Percy F. , Jin Pei , Zhang Juan , Ni Irene , Crawford Damian , Shepard H. Michael , Paleolog Ewa M. , Feldmann Marc
Published: September 2008

Objective

To evaluate the therapeutic potential of the human epidermal growth factor receptor (HER) family inhibitor, herstatin, in an animal model of arthritis.

Methods

Constructs of herstatin and modified tissue plasminogen activator (tPA)–herstatin were expressed in HEK 293T cells, and secreted protein was analyzed by Western blotting. Tissue PA–herstatin adenovirus (Ad‐tPA‐Her) was prepared, and titers established. Gene expression of Ad‐tPA‐Her was determined by polymerase chain reaction using HeLa cells. Pharmacokinetics of gene and protein expression in vivo in liver tissue and serum samples were confirmed via intravenous administration of Ad‐tPA‐Her. Clinical signs of disease were monitored in arthritic DBA/1 mice after therapeutic administration of Ad‐tPA‐Her, and histologic analysis of hind foot specimens was performed.

Results

Native herstatin was not secreted in supernatants, while modified tPA‐herstatin was detected in abundance. HeLa cells stably expressed the tPA‐herstatin gene when infected with virus. Additionally, tPA‐herstatin gene and protein expression was observed over time in mice treated with virus. Importantly, Ad‐tPA‐Her, when administered therapeutically to arthritic mice, controlled clinical and histologic signs of disease and reduced the number of joints with severe damage.

Conclusion

Our results support the notion that the human epidermal growth factor receptor family has a role in the progression of collagen‐induced arthritis. The novel tPA‐herstatin fusion protein could be used as an effective therapeutic tool for control of inflammatory disorders involving an angiogenic component.
NMR‐derived folate‐bound structure of dihydrofolate reductase 1 from the halophile Haloferax volcanii
Authors: Boroujerdi Arezue F. B. , Young John K.
Published: September 2008

Folate binds to dihydrofolate reductase (DHFR) to form a binary complex whose structure maintains the overall configuration of the enzyme; however, some significant changes are evident when a comparison is made to the enzyme. The structure of DHFR1 from the halophilic Halopherax volcanii was solved in its folate‐bound form using nuclear magnetic resonance spectroscopy. NOE data obtained from the 15N‐NOESY‐HSQC and 13C‐NOESY‐HSQC experiments of the triply labeled (1H, 13C, and 15N) binary complex were used as input for the structure calculation with the Crystallography and Nuclear Magnetic Resonance System program. The resulting family of structures was compared with the enzyme solved by both nuclear magnetic resonance and X‐ray crystallography and also to the mesophilic folate‐bound enzyme from Escherichia coli. The binary complex exhibited less convergence of structure in the α2‐helix and differences in the hinge residues D39 and A94. In comparison to the previously reported mesophilic binary complex solved by X‐ray crystallography, the halophilic binary complex reported here does not agree with the convergence of the M20 loop to a single structure. The corresponding L21 loop of the halophilic binary complex family of structures solved by nuclear magnetic resonance indicates variability in this region. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 140–144, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Biophysical characterization of DNA aptamer interactions with vascular endothelial growth factor
Authors: Potty Ajish S. R. , Kourentzi Katerina , Fang Han , Jackson George W. , Zhang Xing , Legge Glen B. , Willson Richard C.
Published: September 2008

The binding of a DNA aptamer (5′‐CCGTCTTCCAGACAAGAGTGCAGGG‐3′) to recombinant human vascular endothelial growth factor (VEGF165) was characterized using surface plasmon resonance (SPR), fluorescence anisotropy and isothermal titration calorimetry (ITC). Results from both fluorescence anisotropy and ITC indicated that a single aptamer molecule binds to each VEGF homodimer, unlike other VEGF inhibitors that exhibit 2(ligand):1(VEGF homodimer) stoichiometry. In addition, ITC revealed that the association of the aptamer to VEGF at 20°C is enthalpically driven, with an unfavorable entropy contribution. SPR kinetic studies, with careful control of possible mass transfer effects, demonstrated that the aptamer binds to VEGF with an association rate constant kon = 4.79 ± 0.03 × 104 M−1 s−1 and a dissociation rate constant koff = 5.21 ± 0.02 × 10−4 s−1 at 25°C. Key recognition hot‐spots were determined by a combination of aptamer sequence substitutions, truncations, and extensions. Most single‐nucleotide substitutions, particularly within an mfold‐predicted stem, suppress binding, whereas those within a predicted loop have a minimal effect. The 5′‐end of the aptamer plays a key role in VEGF recognition, as a single‐nucleotide truncation abolished VEGF binding. Conversely, an 11‐fold increase in the association rate (and affinity) is observed with a single cytosine nucleotide extension, due to pairing of the 3′‐GGG with 5′‐CCC in the extended aptamer. Our approach effectively maps the secondary structural elements in the free aptamer, which present the unpaired interface for high affinity VEGF recognition. These data demonstrate that a directed binding analysis can be used in concert with library screening to characterize and improve aptamer/ligand recognition. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 145–156, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
A role for neoadjuvant gemcitabine plus cisplatin in muscle‐invasive urothelial carcinoma of the bladder
Authors: Dash Atreya , Pettus Joseph A. , Herr Harry W. , Bochner Bernard H. , Dalbagni Guido , Donat S. Machele , Russo Paul , Boyle Mary G. , Milowsky Matthew I. , Bajorin Dean F.
Published: September 2008

BACKGROUND.

Neoadjuvant cisplatin‐based chemotherapy improves survival in muscle‐invasive urothelial cancer, with MVAC (methotrexate, vinblastine, doxorubicin and cisplatin) considered the standard regimen. Gemcitabine plus cisplatin (GC) has similar efficacy and less toxicity than MVAC in metastatic disease, but is untested as neoadjuvant treatment.

METHODS.

The authors retrospectively evaluated patients with muscle‐invasive urothelial carcinoma who received neoadjuvant GC before radical cystectomy between November 2000 and December 2006 at Memorial Sloan‐Kettering Cancer Center. Post‐therapy pathological downstaging to either residual disease at cystectomy (pT0) or no residual muscle‐invasion (<pT2, ie, pT0, pTIS, pT1), chemotherapy delivery, and disease‐free survival were the endpoints of interest. For comparison, similar endpoints were assessed in a historical cohort treated with neoadjuvant MVAC.

RESULTS.

Four cycles of neoadjuvant GC were given over 12 weeks (n = 42). Thirty‐nine (93%) of 42 patients received 4 cycles, with a median 91% drug delivery for cisplatin and 90% for gemcitabine. The pT0 proportion was 26% (95% confidence interval [CI], 14‐42), and no residual muscle‐invasive disease proportion (<pT2) was 36% (95% CI, 21‐52); pT0 was achieved in 28% (95% CI, 16‐42) and <pT2 in 35% (95% CI, 23‐49) of 54 MVAC‐treated patients. All 15 GC patients achieving <pT2 pathologic stage remained disease‐free at a median follow‐up of 30 months.

CONCLUSIONS.

Neoadjuvant GC is feasible and allows for timely drug delivery. The proportion of GC‐treated patients whose primary tumors were downstaged, with prolonged disease‐free survival and minimal or no residual disease, was similar to MVAC‐treated patients. Cancer 2008. © 2008 American Cancer Society.
A randomized phase II trial of adjuvant chemotherapy with uracil/tegafur and gemcitabine versus gemcitabine alone in patients with resected pancreatic cancer
Authors: Yoshitomi Hideyuki , Togawa Akira , Kimura Fumio , Ito Hiroshi , Shimizu Hiroaki , Yoshidome Hiroyuki , Otsuka Masayuki , Kato Atsushi , Nozawa Satoshi , Furukawa Katsunori , Miyazaki Masaru ,   Pancreatic Cancer Chemotherapy Program of the Chiba University Department of General Surgery Affiliated Hospital Group
Published: September 2008

BACKGROUND.

There have been few randomized studies of adjuvant chemotherapy using gemcitabine (GEM) in patients with resected pancreatic cancer.

METHODS.

Patients with invasive ductal pancreatic cancer who underwent radical surgery were enrolled and assigned to receive uracil/tegafur (UFT) and GEM together (GU) or GEM alone (G). GEM was administrated at a dosage of 1 g/m2 intravenously weekly 3 of 4 weeks and UFT at a dosage of 200 mg/day orally continuously. Eligibility included resection status 0 or 1, and no previous chemo‐ or/and radiation therapy. The primary endpoint was disease‐free survival (DFS), and secondary endpoints included overall survival (OS) and toxicity.

RESULTS.

Between 2002 and 2005, 100 patients were randomized into the 2 arms of the trial (50 patients to GU and 50 to G). One patient in the G group was found to be ineligible. Baseline characteristics were well balanced between the 2 groups. With a median observation period of 21 months, the 1‐ and 3‐year DFS rates were 50.0% and 17.7% in the GU group and 49.0% and 21.6% in the G group, respectively. The median OS was 21.2 months in the GU group and 29.8 months in the G group. Toxicity was minor and acceptable, less than grade 4 in both groups.

CONCLUSIONS.

Postoperative GEM‐based adjuvant chemotherapy was safe and well tolerated. However, addition of UFT with GEM did not improve DFS as compared with GEM alone. Further clinical trial resources for adjuvant chemotherapy should address other combinations and novel agents. Cancer 2008. © 2008 American Cancer Society.
Functional maturation of lamina propria dendritic cells by activation of NKT cells mediates the abrogation of oral tolerance
Authors: Chang Jae‐Hoon , Lee Jung‐Mi , Youn Hyun‐Jun , Lee Kyoo‐A , Chung Yeonseok , Lee Ah‐Young , Kweon Mi‐Na , Kim Ho‐Youn , Taniguchi Masaru , Kang Chang‐Yuil
Published: September 2008

We previously showed that although systemic administration of α‐galactosylceramide (αGalCer) or agonistic anti‐CD40 induced functional maturation of dendritic cells (DC) in mesenteric lymph nodes, only the former treatment succeeded in breaking the induction of oral tolerance. In this study, we looked for the essential factor responsible for the disruption of oral tolerance. We found that lamina propria (LP)‐DC was responsible for the oral OVA presentation and that Peyer's patch was not essential for the induction of oral tolerance. Therefore, we investigated the role of LP‐DC. Treatment with αGalCer but not with anti‐CD40 induced the full maturation of LP‐DC at an early time point. This functional activation of LP‐DC was mediated by strong activation of NKT cells that reside abundantly in the small intestinal lamina propria (SI‐LP) and interferon‐γ partially contributed to the LP‐DC activation. LP‐DC isolated from αGalCer‐treated OVA‐fed mice induced the differentiation of naïve CD4+ T cells into Th1 and Th2 and was associated with the reduced Foxp3+ population. In contrast, LP‐DC isolated from anti‐CD40‐treated OVA‐fed mice failed to generate Th cell differentiation but induced more Foxp3+ CD4+ T cells. Our results demonstrate that triggered by NKT cells in SI‐LP, functional maturation of Ag‐capturing DC from SI‐LP is necessary for the abrogation of oral tolerance induction.
Th memory for interleukin‐17 expression is stable in vivo
Authors: Lexberg Maria H. , Taubner Annegret , Förster Anna , Albrecht Inka , Richter Anne , Kamradt Thomas , Radbruch Andreas , Chang Hyun‐Dong
Published: September 2008

Based on the memory for the re‐expression of certain cytokine genes, different subsets of Th cells have been defined. In Th type 1 (Th1) and Th2 memory lymphocytes, the genes for the cytokines interferon‐γ and interleukin (IL)‐4 are imprinted for expression upon restimulation by the expression of the transcription factors T‐bet and GATA‐3, respectively, and epigenetic modification of the cytokine genes. In Th17 cells, IL‐17 expression is dependent on the transcription factors RORγt and RORα. Here, we analyze the stability and plasticity of IL‐17 memory in Th17 cells. We have developed a cytometric IL‐17 secretion assay for the isolation of viable Th cells secreting IL‐17. For Th17 cells generated in vitro, IL‐17 expression itself is dependent on continued TGF‐β/IL‐6 or IL‐23 signaling and is blocked by interferon‐γ and IL‐4 signaling. In response to IL‐12 and IL‐4, in vitro generated Th17 cells are converted into Th1 or Th2 cells, respectively. Th17 cells isolated ex vivo, however, maintain their IL‐17 memory upon subsequent in vitro culture, even in the absence of IL‐23. Their cytokine memory is not regulated by IL‐12 or IL‐4. Th17 cells generated in vivo are a stable and distinct lineage of Th cell differentiation.
Frequency dependence of viscoelastic properties of medical grade silicones
Authors: Mahomed A. , Chidi N. M. , Hukins D. W. L. , Kukureka S. N. , Shepherd D. E. T.
Published: September 2008

Cylinders of medical grade silicone elastomers, (29 mm in diameter and 13 mm thick), immersed in physiological saline solution at 37°C, were investigated by dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 ± 5 N was applied over a frequency range, f, of 0.02–100 Hz. Values of the storage, E′, and loss, E″, moduli for the cylinders were found to depend on f; the dependence of E′ or E″ on the logarithm (base 10) of f was represented by a third‐order polynomial. Above about 0.3 Hz, the cylindrical specimens appeared to be undergoing the onset of a transition from the rubbery to the glassy state. There was no significant difference between results obtained at 37 and 23°C; pretreatment of specimens in physiological saline at 37°C for 24 h and 29 days had no appreciable effect on the results. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Stability of carbon‐centered radicals: Effect of functional groups on the energetics of addition of molecular oxygen
Authors: Wright James S. , Shadnia Hooman , Chepelev Leonid L.
Published: September 2008

In this paper we examine a series of hydrocarbons with structural features which cause a weakening of the CH bond. We use theoretical calculations to explore whether the carbon‐centered radicals R• which are created after breaking the bond can be stabilized enough so that they resist the addition of molecular oxygen, i.e. where the reaction R• + O2 → ROO• becomes energetically unfavorable. Calculations using a B3LYP‐based method provide accurate bond dissociation enthalpies (BDEs) for RH and ROO• bonds, as well as Gibbs free energy changes for the addition reaction. The data show strong correlations between ROO• and RH BDEs for a wide variety of structures. They also show an equally strong correlation between the ROO• BDE and the unpaired spin density at the site of addition. Using these data we examine the major functional group categories proposed in several experimental studies, and assess their relative importance. Finally, we combine effects to try to optimize resistance to the addition of molecular oxygen, an important factor in designing carbon‐based antioxidants. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
The inverse methodology of parameter estimation for model adjustment, design, simulation, control and optimization of fluid catalytic cracking (FCC) risers
Authors: Souza J. A. , Vargas J. V. C. , von Meien O. F. , Martignoni W. P. , Ordonez J. C.
Published: September 2008

BACKGROUND: A simple model is required to produce a fast computational code that is sufficiently precise to be used for the design, simulation, control and optimization of fluid catalytic cracking (FCC) risers. This work experimentally validates and adjusts a simplified FCC riser model using available experimental data, and proposes utilization of the inverse problem of the parameter estimation method to fit any existing kinetic model to a specific feedstock/catalyst set for general application.

RESULTS: The model adjustment procedure was repeated for nine different experimental sets and the best fitting parameters were obtained statistically. The fitting parameters were utilized to predict the riser output conditions for the other 18 data sets. The numerical results are in good quantitative and qualitative agreement with the experimental data. The model was then utilized to simulate an industrial FCC riser, predicting concentrations and temperature profiles from the bottom to the top of the riser.

CONCLUSIONS: The results suggest that the simplified model, combined with the proposed inverse methodology could produce accurate results for any feedstock/catalyst set, once the kinetic model is known for a particular feedstock/catalyst set. Therefore, a low computational time and accurate tool is made available for simulation, control, design and optimization of FCC risers. Copyright © 2008 Society of Chemical Industry
Reproducible MRI measurement of adipose tissue volumes in genetic and dietary rodent obesity models
Authors: Johnson David H. , Flask Chris A. , Ernsberger Paul R. , Wong Wilbur C.K. , Wilson David L.
Published: September 2008

Purpose

To develop ratio MRI [lipid/(lipid+water)] methods for assessing lipid depots and compare measurement variability with biological differences among lean controls (spontaneously hypertensive rats [SHRs]), dietary obese rats (SHR‐DOs), and genetic/dietary obese rats (SHROBs).

Materials and Methods

Images with and without chemical shift‐selective (CHESS) water suppression were processed using a semiautomatic method that accounts for relaxometry, chemical shift, receive coil sensitivity, and partial volume.

Results

Partial volume correction improved results by 10% to 15%. Over six operators, volume variation was reduced to 1.9 mL from 30.6 mL for single‐image‐analysis with intensity inhomogeneity. For three acquisitions on the same animal, volume reproducibility was <1%. SHROBs had six times more visceral and eight times more subcutaneous adipose tissue than SHRs. SHR‐DOs had enlarged visceral depots (three times larger than those in SHRs). SHROBs had significantly more subcutaneous adipose tissue, indicating a strong genetic component to this fat depot. Liver ratios in SHR‐DO and SHROB were higher than in SHR, indicating elevated fat content. Among SHROBs, evidence suggested a phenotype SHROB* having elevated liver ratios and visceral adipose tissue volumes.

Conclusion

Effects of diet and genetics on obesity were significantly larger than variations due to image acquisition and analysis, indicating that these methods can be used to assess accumulation/depletion of lipid depots in animal models of obesity. J. Magn. Reson. Imaging 2008;28:915–927. © 2008 Wiley‐Liss, Inc.
Traumatic extra‐axial hemorrhage: Correlation of postmortem MSCT, MRI, and forensic‐pathological findings
Authors: Añon Javier , Remonda Luca , Spreng Adrian , Scheurer Eva , Schroth Gerhard , Boesch Chris , Thali Michael , Dirnhofer Richard , Yen Kathrin
Published: September 2008

Purpose

To evaluate the diagnostic accuracy of in situ postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) in the detection of primary traumatic extra‐axial hemorrhage.

Materials and Methods

Thirty forensic neurotrauma cases and 10 nontraumatic controls who underwent both in situ postmortem cranial MSCT and MR imaging before autopsy were retrospectively reviewed. Both imaging modalities were analyzed in view of their accuracy, sensitivity, and specificity concerning the detection of extra‐axial hemorrhage. Statistical significance was calculated using the McNemar test. κ values for interobserver agreement were calculated for extra‐axial hemorrhage types and to quantify the agreement between both modalities as well as MRI, CT, and forensics, respectively.

Results

Analysis of the detection of hemorrhagic localizations showed an accuracy, sensitivity, and specificity of 89%, 82%, and 92% using CT, and 90%, 83%, and 94% using MRI, respectively. MRI was more sensitive than CT in the detection of subarachnoid hemorrhagic localizations (P = 0.001), whereas no significant difference resulted from the detection of epidural and subdural hemorrhagic findings (P = 0.248 and P = 0.104, respectively). Interobserver agreement for all extra‐axial hemorrhage types was substantial (CT κ = 0.76; MRI κ = 0.77). The agreement of both modalitites was almost perfect (readers 1 and 2 κ = 0.88).

Conclusion

CT and MRI are of comparable potential as forensic diagnostic tools for traumatic extra‐axial hemorrhage. Not only of forensic, but also of clinical interest is the observation that most thin blood layers escape the radiological evaluation. J. Magn. Reson. Imaging 2008;28:823–836. © 2008 Wiley‐Liss, Inc.
Maturational changes in diffusion anisotropy in the rat corpus callosum: Comparison with quantitative histological evaluation
Authors: Jito Junya , Nakasu Satoshi , Ito Ryuta , Fukami Tadateru , Morikawa Shigehiro , Inubushi Toshiro
Published: September 2008

Purpose

To determine the main histological components that affect fractional anisotropy (FA) in postnatal development of the rat corpus callosum and compare FA values with histological changes evaluated quantitatively.

Materials and Methods

Diffusion tensor image (DTI) data of the rat (postnatal 1–10 weeks) corpus callosum were obtained with a 7.0 T MR scanner. Histological parameters were quantitatively assessed in toluidine blue‐stained semithin sections. Simple and multiple linear regression analyses were performed to investigate relationships between FA values and histological variables.

Results

The mean FA value (mFA) increased significantly in the early growth stages, whereas the change became smaller after postnatal week 4. Simple regression analysis showed a high correlation between the area of myelin sheath and mFA (r = 0.856; P < 0.01). The area of extracellular space correlated negatively with mFA (r = −0.813; P < 0.01). In a forward stepwise analysis, the area of myelin sheath had the strongest influence on mFA (P < 0.001), followed by the number of unmyelinated axons (P = 0.113). Multiple linear regression analysis revealed that both parameters predicted mFA with a highly significant adjusted correlation coefficient (r2 adj. = 0.738, P < 0.001).

Conclusion

During the early development stage in the rat corpus callosum, the strongest contribution to FA value is the area of myelin sheath. J. Magn. Reson. Imaging 2008;28:847–854. © 2008 Wiley‐Liss, Inc.
Manganese‐enhanced MRI of the rat visual pathway: Acute neural toxicity, contrast enhancement, axon resolution, axonal transport, and clearance of Mn2+
Authors: Thuen Marte , Berry Martin , Pedersen Tina Bugge , Goa Pål Erik , Summerfield Mike , Haraldseth Olav , Sandvig Axel , Brekken Christian
Published: September 2008

Purpose

To provide dose‐response data for the safe and effective use of MnCl2 for manganese (Mn2+) ‐enhanced MRI (MEMRI) of the visual pathway.

Materials and Methods

Retinal ganglion cell (RGC) toxicity, CNR in MEMRI, axon density resolution for MEMRI, mode of axonal transport and clearance of Mn2+ from the vitreous after ivit were investigated. After 0, 30, 150, 300, 1500, and 3000 nmol ivit MnCl2, neural toxicity was measured by counting surviving RGC back‐filled with FluroGold (FG), CNR of the vitreous body and visual pathway by three‐dimensional (3D) MEMRI, resolution of ON axon density by correlating CNR with axon density, and axonal transport of Mn2+ by studying CNR in 3D MEMRI of the ON after ion of 200 nmol MnCl2.

Results

There were no changes in RGC density after ivit MnCl2 ≤ 150 nmol, and reductions of 12%, 57%, and 94% occurred after 300, 1500, and 3000 nmol MnCl2. CNR increased in the visual pathway with MnCl2 ≤ 300 nmol, and decreased when the dose was raised further. Minimum detectable ON axon densities were 125,000/mm2. After 200 nmol ion MnCl2, CNR>0 were recorded distally from the ion site, but there was no signal in the retina. At ivit doses >1500 nmol, clearance from the vitreous body was impaired.

Conclusion

The optimal dose for MEMRI of the rat visual pathway was found to be 150–300 nmol ivit MnCl2. Higher doses are toxic, causing RGC death, impair active clearance from the vitreous, and loss of Mn2+ enhancement throughout the visual pathway. Mn2+ traffic within RGC axons is mediated mainly by anterograde transport. J. Magn. Reson. Imaging 2008;28:855–865. © 2008 Wiley‐Liss, Inc.
Evaluation of referenceless thermometry in MRI‐guided focused ultrasound surgery of uterine fibroids
Authors: McDannold Nathan , Tempany Clare , Jolesz Ferenc , Hynynen Kullervo
Published: September 2008

Purpose

To clinically assess a previously described method (Rieke et.al., Magn Reson Med 2004) to produce more motion‐robust MRI‐based temperature images using data acquired during MRI‐guided focused ultrasound surgery (MRgFUS) of uterine fibroids.

Materials and Methods

The method (“referenceless thermometry”) uses surface fitting in nonheated regions of individual phase images to extrapolate and then remove background phase variations that are unrelated to temperature changes. We tested this method using images from 100 sonications selected from 33 patient MRgFUS treatments. Temperature measurements and thermal dose contours estimated with the referenceless method were compared with those produced with the standard phase‐difference technique. Fitting accuracy and noise level were also measured.

Results

In 92/100 sonications, the difference between the two measurements was less than 3°C. The average difference in the measurements was 1.5 ± 1.4°C. Small motion artifacts were observed in the phase‐difference imaging when the difference was greater than 3°C. The method failed in two cases. The mean absolute error in the surface fit in baseline images corresponded to a temperature error of 0.8 ± 1.4°C. The noise level was approximately 40% lower than the phase‐difference method. Thermal dose contours calculated from the two methods agreed well on average.

Conclusion

Based on the small error when compared with the standard technique, this method appears to be adequate for temperature monitoring of MRgFUS in uterine fibroids and may prove useful for monitoring temperature changes in moving organs. J. Magn. Reson. Imaging 2008;28:1026–1032. © 2008 Wiley‐Liss, Inc.
Identifying lesion growth with MR imaging in acute ischemic stroke
Authors: Bristow Michael S. , Poulin Brett W. , Simon Jessica E. , Hill Michael D. , Kosior Jayme C. , Coutts Shelagh B. , Frayne Richard , Mitchell J. Ross , Demchuk Andrew M.
Published: September 2008

Purpose

To determine whether different MR diffusion‐ and perfusion‐weighted imaging (DWI and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia.

Materials and Methods

MR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION ‐ intersection of acute and final lesions, (ii) GROWTH ‐ portion of final lesion not part of acute lesion, and (iii) OLIGEMIA ‐ region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel‐wise basis using DWI‐ and PWI‐based parameters. Final models were selected based on the Wald statistic and validated by cross‐validation using the mean (± standard deviation) area under the curve (AUC) from receiver operating characteristic analysis.

Results

The final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 ± 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time‐to‐peak (AUC = 0.793 ± 0.106).

Conclusion

Different MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke. J. Magn. Reson. Imaging 2008;28:837–846. © 2008 Wiley‐Liss, Inc.
Quantitative analysis of diffusion‐weighted magnetic resonance imaging of the pancreas: Usefulness in characterizing solid pancreatic masses
Authors: Lee Seung Soo , Byun Jae Ho , Park Beom Jin , Park Seong Ho , Kim Namkug , Park Bumwoo , Kim Jeong Kon , Lee Moon‐Gyu
Published: September 2008

Purpose

To evaluate whether measurement of apparent diffusion coefficient (ADC) and pure diffusion coefficient (D) can help to characterize solid pancreatic masses.

Materials and Methods

Diffusion‐weighted MR imaging was performed in both a patient group (n = 71; pancreatic cancer [n = 47], mass‐forming pancreatitis [n = 13], solid pseudopapillary neoplasm [n = 6], and neuroendocrine tumor [n = 5]) and a normal control group (n = 11) by applying three b‐factors of 0, 500, and 1000 sec/mm2. ADC500, ADC1000, D (ADC using b = 500 and 1000 sec/mm2), and perfusion fraction (f, 1‐ exp [‐500 sec/mm2 × (ADC500 – D)]) of normal pancreas, pancreatic cancer, and mass‐forming pancreatitis were compared using the Kruskal–Wallis test. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance and optimal cutoff value of these parameters in differentiating pancreatic cancer from mass‐forming pancreatitis.

Results

Normal pancreas had significantly higher mean ADC500, ADC1000, and f than either pancreatic cancer (P < 0.001, < 0.001, and 0.004, respectively) or mass‐forming pancreatitis (P < 0.001, < 0.001, and 0.002, respectively). ADC500, ADC1000, and D of mass‐forming pancreatitis were significantly lower than those of pancreatic cancer (P = 0.002, 0.004, and 0.014, respectively). Sensitivities and specificities in the diagnosis of pancreatic cancer were 72.3% and 76.9% for ADC500, 87.2% and 69.2% for ADC1000, 87.2% and 61.5% for D, and 42.6% and 92.3% for f, respectively.

Conclusion

Measurement of ADC and D may be helpful in differentiating pancreatic cancers from mass‐forming pancreatitis. J. Magn. Reson. Imaging 2008;28:928–936. © 2008 Wiley‐Liss, Inc.
USPIO (Ferumoxtran‐10)‐enhanced MRI to visualize reticuloendothelial system cells in neonatal rats: Feasibility and biodistribution study
Authors: Azoulay Robin , Olivier Paul , Baud Olivier , Verney Catherine , Santus Robin , Robert Philippe , Gressens Pierre , Sebag Guy
Published: September 2008

Purpose

To investigate whether USPIO‐enhanced magnetic resonance imaging (MRI) detected reticuloendothelial system (RES) cells in newborn normal rats.

Materials and Methods

Newborn normal rats were imaged in vivo on a 1.5 T MR system, 2–96 hours after intraperitoneal Ferumoxtran‐10 (n = 38) or saline injection (control group, n = 5). Signals from liver, spleen, and vertebral bone marrow were measured (T2‐weighted Turbo Spin Echo) to describe the kinetics of enhancement. The pups were sacrificed and iron concentrations in plasma and peritoneal fluid were measured using atomic absorption spectrometry. Prussian blue‐labeled cells density in liver, spleen, and vertebral bone marrow was assessed.

Results

Significant (P < 0.05) negative enhancement of the liver, spleen, and vertebral bone marrow was noted after Ferumoxtran‐10 injection (2–96 hours for liver and spleen, 4–96 hours for bone marrow). Ferumoxtran‐10 was absorbed from the peritoneum in the first 8 hours postinjection, entering the circulation with a plasma peak (8 hours); then Ferumoxtran‐10 returned over the baseline in plasma (96 hours). Important intracellular iron deposition in liver and spleen was measured postinjection (3–96 hours, P < 0.05). Limited but significant intracellular iron deposition was noted in vertebral bone marrow postinjection (96 hours, P < 0.05), suggesting that Ferumoxtran‐10 selectively labeled RES cells after 96 hours and produced nonspecific labeling at earlier timepoints.

Conclusion

Ferumoxtran‐10‐enhanced MRI visualizes RES cells in vivo in newborn rats. J. Magn. Reson. Imaging 2008;28:1046–1052. © 2008 Wiley‐Liss, Inc.
Improvement of MRI‐functional measurement with automatic movement correction in native and transplanted kidneys
Authors: de Senneville Baudouin Denis , Mendichovszky Iosif Alexandru , Roujol Sébastien , Gordon Isky , Moonen Chrit , Grenier Nicolas
Published: September 2008

Purpose

To improve 2D software for motion correction of renal dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and to evaluate its effect using the Patlak–Rutland model.

Materials and Methods

A subpixel‐accurate method to correct for kidney motion during DCE‐MRI was evaluated on native and transplanted kidneys using data from two different institutions with different magnets and protocols. The Patlak–Rutland model was used to calculate glomerular filtration rate (GFR) on a voxel‐by‐voxel basis providing mean (K̄p) and uncertainty (σ(Kp)) values for GFR.

Results

In transplanted kidneys, average absolute variation of K̄p was 6.4% ± 4.8% (max = 16.6%). In native kidneys average absolute variation of K̄p was 12.11% ± 6.88% (max = 25.6%) for the right and 11.6% ± 6% (max = 20.8%) for the left. Movement correction showed an average reduction ofσ(Kp) of 6.9% ± 6.6% (max = 21.4%) in transplanted kidneys, 30.9% ± 17.6% (max = 60.8%) for the right native kidney, and 31.8% ± 14% (max = 55.3%) for the left kidney.

Conclusion

The movement correction algorithm showed improved uncertainty on GFR computation for both native and transplanted kidneys despite different spatial resolution from the different MRI systems and different levels of signal‐to‐noise ratios on DCE‐MRI. J. Magn. Reson. Imaging 2008;28:970–978. © 2008 Wiley‐Liss, Inc.
Magnetization transfer contrast and T2 mapping in the evaluation of cartilage repair tissue with 3T MRI
Authors: Welsch Goetz H. , Trattnig Siegfried , Scheffler Klaus , Szomonanyi Pavol , Quirbach Sebastian , Marlovits Stefan , Domayer Stephan , Bieri Oliver , Mamisch Tallal C.
Published: September 2008

Purpose

To use magnetization transfer (MT) imaging in the visualization of healthy articular cartilage and cartilage repair tissue after different cartilage repair procedures, and to assess global as well as zonal values and compare the results to T2‐relaxation.

Materials and Methods

Thirty‐four patients (17 after microfracture [MFX] and 17 after matrix‐associated autologous cartilage transplantation [MACT]) were examined with 3T MRI. The MT ratio (MTR) was calculated from measurements with and without MT contrast. T2‐values were evaluated using a multiecho, spin‐echo approach. Global (full thickness of cartilage) and zonal (deep and superficial aspect) region‐of‐interest assessment of cartilage repair tissue and normal‐appearing cartilage was performed.

Results

In patients after MFX and MACT, the global MTR of cartilage repair tissue was significantly lower compared to healthy cartilage. In contrast, using T2, cartilage repair tissue showed significantly lower T2 values only after MFX, whereas after MACT, global T2 values were comparable to healthy cartilage. For zonal evaluation, MTR and T2 showed a significant stratification within healthy cartilage, and T2 additionally within cartilage repair tissue after MACT.

Conclusion

MT imaging is capable and sensitive in the detection of differences between healthy cartilage and areas of cartilage repair and might be an additional tool in biochemical cartilage imaging. For both MTR and T2 mapping, zonal assessment is desirable. J. Magn. Reson. Imaging 2008;28:979–986. © 2008 Wiley‐Liss, Inc.
Reactive hyperemia and BOLD MRI demonstrate that VEGF inhibition, age, and atherosclerosis adversely affect functional recovery in a murine model of peripheral artery disease
Authors: Greve Joan M. , Williams Simon P. , Bernstein Lisa J. , Goldman Hope , Peale Franklin V. , Bunting Stuart , van Bruggen Nicholas
Published: September 2008

Purpose

To develop magnetic resonace imaging (MRI) methods for functional assessment of arteriogenesis in a murine model of peripheral artery disease to quantify the influences of vascular endothelial growth factor (VEGF), age, and atherosclerosis.

Materials and Methods

Reactive hyperemia (RH), which was induced using a device designed for remote and transient occlusion of the aorta and vena cava, was measured by blood‐oxygen‐level–dependent MRI. Twenty‐eight days after femoral artery ligation, peak height (PH) and time to peak (TTP) of the RH response was compared with sham‐operated animals in 10‐week‐old C57Bl6, 9‐month‐old C57Bl6, and 9‐month‐old Ldlr−/−Apobec−/− mice. The contribution of VEGF to functional recovery was assessed in young mice. Angiogenesis was quantified using an anti‐PECAM1 radioimmunoassay.

Results

In young animals, angiogenesis was maximal 7 days after ligation, whereas functional recovery took 28 days. Inhibition of VEGF eliminated the angiogenesis seen at 7 days and reduced RH (PH, P < 0.05). At day 28, RH was altered in old (TTP, P < 0.05) and atherosclerotic (PH, P < 0.05; TTP, P < 0.05) animals. RH was different in young, old, and atherosclerotic sham animals. Old and atherosclerotic mice showed reduced angiogenesis.

Conclusion

The method presented herein can provide a sensitive assay for the functional assessment of arteriogenesis and highlights the contribution of VEGF, age, and atherosclerosis to this process. J. Magn. Reson. Imaging 2008;28:996–1004. © 2008 Wiley‐Liss, Inc.
Transvascular and interstitial transport in rat hepatocellular carcinomas: Dynamic contrast‐enhanced MRI assessment with low‐ and high‐molecular weight agents
Authors: Michoux Nicolas , Huwart Laurent , Abarca‐Quinones Jorge , Dorvillius Mylène , Annet Laurence , Peeters Frank , Van Beers Bernard E.
Published: September 2008

Purpose

To assess which MRI‐derived kinetic parameters reflect decreased transvascular and interstitial transport when low‐ and high‐molecular‐weight agents are used in rat hepatocellular carcinomas.

Materials and Methods

Dynamic MRI after injection of a low‐molecular‐weight contrast agent of 0.56 kDa (Gd‐DOTA, gadoterate) and two high‐molecular‐weight contrast agents of 6.47 kDa (P792, gadomelitol) and 52 kDa (P717, carboxymethyldextran Gd‐DOTA) was performed in rats with chemically induced hepatocellular carcinomas. The data were analyzed with the Kety compartmental model, the extended Kety compartmental model in which it is assumed that the tissue voxels contain a vascular component, and the St Lawrence and Lee distributed‐parameter model.

Results

The extravascular extracellular space accessible to the contrast agent ve and the extraction fraction E decreased with increasing molecular weight of the contrast agent. In contrast, the volume transfer constant Ktrans did not differ significantly when low‐ or high‐molecular‐weight agents were used.

Conclusion

In this animal model the results suggest that the accessible extravascular extracellular space and the extraction fraction are more sensitive indicators of decreased transvascular and interstitial transport with high‐molecular‐weight agents than the volume transfer constant, which is a lumped representation of blood flow and permeability. J. Magn. Reson. Imaging 2008;28:906–914. © 2008 Wiley‐Liss, Inc.
Perfusion‐weighted magnetic resonance imaging patterns of hypoxic–ischemic encephalopathy in term neonates
Authors: Wintermark Pia , Moessinger Adrien C. , Gudinchet François , Meuli Reto
Published: September 2008

Purpose

To determine whether an early magnetic resonance imaging (MRI) study using perfusion‐weighted imaging (PWI) may define the pattern of brain injury in term neonatal hypoxic–ischemic (HI) encephalopathy.

Materials and Methods

Five newborns with HI encephalopathy or a marker of perinatal depression, and 2 controls underwent an early MRI (at 2 to 4 days), including PWI. Relative cerebral blood flow (rCBF) values were measured.

Results

On early (≤4 days) PWI‐MRI, marked hyperperfusion was seen in areas of HI brain damage, allowing the classification of the children into different patterns according to the predominant site of injury: 1 with a “normal pattern”; 1 with a “watershed pattern” with increased rCBF ratios in white matter; 1 with a “basal ganglia pattern” with increased rCBF ratios in basal ganglia; and 2 with a “total cortical pattern” with increased rCBF ratios in cortical gray matter, white matter, and basal ganglia. These patterns were confirmed in all infants on late (9 to 11 days) conventional MRI (T2‐weighted images) (4 of 5 patients) or on postmortem examination (1 of 5 patients).

Conclusion

PWI is technically feasible in neonates with HI encephalopathy in a reproducible way, permitting comparisons between children. It provides a practical means to identify early after birth the future definitive ischemic areas that may be shown on conventional MRI only later. J. Magn. Reson. Imaging 2008;28:1019–1025. © 2008 Wiley‐Liss, Inc.
In vivo 1H magnetic resonance spectroscopy of amniotic fluid and fetal lung at 1.5 T: Technical challenges
Authors: Kim Dong‐Hyun , Vahidi Kiarash , Caughey Aaron B. , Coakley Fergus V. , Vigneron Daniel B. , Kurhanewicz John , Mow Ben , Joe Bonnie N.
Published: September 2008

Purpose

To identify the major technical challenges associated with in utero single‐voxel proton spectroscopy of amniotic fluid and fetal lung and to evaluate the feasibility of performing in utero fetal spectroscopy for fetal lung maturity testing.

Materials and Methods

Fetal magnetic resonance (MR) spectroscopy of amniotic fluid and fetal lung were performed at 1.5 T in 8 near‐term pregnant women. Presence/absence of lactate and choline peaks was tabulated. Ex vivo spectra were obtained from amniotic fluid samples to investigate and refine sequence parameters.

Results

Spectroscopy failed in 3 of 8 cases due to maternal discomfort (n = 1) or fetal gastroschisis (n = 2). Both fetal motion and low signal‐to‐noise ratio were limiting factors for the remaining 5 clinical in vivo studies at 1.5 T. Ex vivo and in vivo studies suggested feasibility for detecting lactate from amniotic fluid within a reasonable clinical scan time (4–5 minutes). Lactate was detected in 3 of 5 patients. Choline detection was limited and was detected in 1 patient.

Conclusion

Minor motion effects can be overcome but continuous fetal motion is problematic. Lactate detection seems clinically feasible, but choline detection requires additional technical development and, potentially, further imaging at a higher field strength because of the low signal‐to‐noise ratio at 1.5 T. J. Magn. Reson. Imaging 2008;28:1033–1038. © 2008 Wiley‐Liss, Inc.
Signal features of the atherosclerotic plaque at 3.0 Tesla versus 1.5 Tesla: Impact on automatic classification
Authors: Kerwin William S. , Liu Fei , Yarnykh Vasily , Underhill Hunter , Oikawa Minako , Yu Wei , Hatsukami Thomas S. , Yuan Chun
Published: September 2008

Purpose

To investigate the impact of different field strengths on determining plaque composition with an automatic classifier.

Materials and Methods

We applied a previously developed automatic classifier—the morphology enhanced probabilistic plaque segmentation (MEPPS) algorithm—to images from 20 subjects scanned at both 1.5 Tesla (T) and 3T. Average areas per slice of lipid‐rich core, intraplaque hemorrhage, calcification, and fibrous tissue were recorded for each subject and field strength.

Results

All measurements showed close agreement at the two field strengths, with correlation coefficients of 0.91, 0.93, 0.95, and 0.93, respectively. None of these measurements showed a statistically significant difference between field strengths in the average area per slice by a paired t‐test, although calcification tended to be measured larger at 3T (P = 0.09).

Conclusion

Automated classification results using an identical algorithm at 1.5T and 3T produced highly similar results, suggesting that with this acquisition protocol, 3T signal characteristics of the atherosclerotic plaque are sufficiently similar to 1.5T characteristics for MEPPS to provide equivalent performance. J. Magn. Reson. Imaging 2008;28:987–995. © 2008 Wiley‐Liss, Inc.
Diffusion‐weighted MR imaging for the evaluation of seminal vesicle invasion in prostate cancer: Initial results
Authors: Kim Chan Kyo , Choi Dongil , Park Byung Kwan , Kwon Ghee Young , Lim Hyo Keun
Published: September 2008

Purpose

To evaluate the accuracy of T2‐weighted (T2WI) with diffusion‐weighted imaging (DWI) as compared with T2WI alone for predicting seminal vesicle invasion (SVI) of prostate cancer.

Materials and Methods

A total of 30 patients with SVI and 136 patients without SVI who underwent prostate MR imaging were included in the study. MR images were analyzed retrospectively and independently by two readers for SVI on T2WI and T2WI with DWI using a 5‐point scale.

Results

For predicting SVI, the specificity for T2WI with DWI and for T2WI was 97% and 87%, respectively, and accuracy was 96% and 87%, respectively, as determined by the experienced reader (P < 0.01). For the less experienced reader, the specificity for T2WI with DWI and for T2WI was 96% and 81%, respectively, and accuracy was 90% and 77%, respectively (P < 0.01). The diagnostic performance of the less experienced reader with T2WI with DWI led to significant improvement of the area under the receiver operating characteristic curve (Az) as compared with T2WI alone (Az = 0.815 versus 0.696; P < 0.01). Interreader agreement showed a substantial agreement (κ = 0.613) for T2WI, and a substantial agreement (κ = 0.737) for T2WI with DWI.

Conclusion

For predicting SVI, T2WI with DWI showed a better diagnostic performance than T2WI alone. Additionally, the accuracy of the less experienced reader using T2WI with DWI showed a significant improvement as compared with T2WI alone. J. Magn. Reson. Imaging 2008;28:963–969. © 2008 Wiley‐Liss, Inc.