bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capture of human monoclonal antibodies from a clarified cell culture supernatant by phenyl boronate chromatography
Authors: Azevedo Ana M. , Gomes A. G. , Borlido L. , Santos I. F. S. , Prazeres D. M. F. , Aires‐Barros M. R. 
Published: October 2010

AbstractIn this work, we investigated the feasibility of using phenyl boronate (PB) chromatography for the direct capture of monoclonal antibodies from a CHO cell supernatant. Preliminary results, using pure protein solutions have shown that PB media can bind to human antibodies, not only at strong alkaline conditions but also at acidic pH values. In fact, antibodies have been found to bind in the pH range 5.5–8.5. On the other hand, insulin and human serum albumin did not bind at alkaline pH but at lower pH, which reflects the importance of non‐specific interactions with the matrix. Different binding and eluting buffers were evaluated for the capture of immunoglobulin G (IgG) from a CHO cell supernatant and the most promising results were obtained using 20 mM 4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid at pH 8.5 as binding buffer and 1.5 M Tris–HCl as eluting buffer. Using a step elution, all IgG was recovered in the elution pool with a maximum purification factor of 56. A gradient elution allowed a further increase of the final purity, yet achieving a slightly lower yield. IgG recovery was around 85% and the purification factor was 76. The highest purity was obtained when the pH of the cell supernatant feed was previously adjusted to 8.5. Starting from an initial protein purity of 1.1% and high‐performance liquid chromatography (HPLC) purity of 2.2%, after PB adsorption, a final protein purity of 85% and a HPLC purity of 88% was achieved. Copyright © 2010 John Wiley & Sons, Ltd.
A new affinity approach to isolateEscherichia coli6S RNA with histidine‐chromatography
Authors: Martins R. , Queiroz J. A. , Sousa F. 
Published: October 2010

Abstract6S RNA is an abundant non‐coding RNA inEscherichia coli(E.coli), but its function has not been discovered until recently. The first advance on 6S RNA function was the demonstration of its ability to bind the σ70‐holoenzyme form of RNA polymerase, inhibiting its activity and consequently the transcription process. The growing interest in the investigation of non‐coding small RNAs (sRNA) calls for the development of new methods for isolation and purification of RNA. This work presents an optimized RNA extraction procedure and describes a new affinity chromatography method using a histidine support to specifically purify 6S RNA from otherE. colisRNA species. The RNA extraction procedure was optimized, and a high yield was obtained in the separation of sRNA and ribosomal RNA (rRNA) from total RNA (RNAt). This improved method takes advantage of its simplicity and significant cost reduction, since some complex operations have been eliminated. A purification strategy was also developed to separate 6S RNA from an sRNA mixture. Pure RNA can be advantageously obtained using the histidine‐affinity chromatography method, aiming at its application to structural or functional studies. Copyright © 2010 John Wiley & Sons, Ltd.
Solid‐phase preparation of protein complexes
Authors: Pengo Paolo , Veggiani Gianluca , Rattanamanee Kwanchai , Gallotta Andrea , Beneduce Luca , Fassina Giorgio 
Published: October 2010

AbstractProtein–protein conjugation is usually achieved by solution phase methods requiring concentrated protein solution and post‐synthetic purification steps. In this report we describe a novel continuous‐flow solid‐phase approach enabling the assembly of protein complexes minimizing the amount of material needed and allowing the repeated use of the same solid phase. The method exploits an immunoaffinity matrix as solid support; the matrix reversibly binds the first of the complex components while the other components are sequentially introduced, thus allowing the complex to grow while immobilized. The tethering technique employed relies on the use of the very mild synthetic conditions and fast association rates allowed by the avidin–biotin system. At the end of the assembly, the immobilized complexes can be removed from the solid support and recovered by lowering the pH of the medium. Under the conditions used for the sequential complexation and recovery, the solid phase was not damaged or irreversibly modified and could be reused without loss of binding capacity. The method was specifically designed to prepare protein complexes to be used in immunometric methods of analysis, where the immunoreactivity of each component needs to be preserved. The approach was successfully exploited for the preparation of two different immunoaffinity reagents with immunoreactivity mimicking native squamous cell carcinoma antigen‐immunoglobulin M (SCCA‐IgM) and alphafetoprotein‐immunoglobulin M (AFP‐IgM) immune complexes, which were characterized by dedicated sandwich enzyme‐linked immunosorbent assay (ELISA) and immunoblot. Besides the specific application described in the paper, the method is sufficiently general to be used for the preparation of a broad range of protein assemblies. Copyright © 2010 John Wiley & Sons, Ltd.
Optimization of high‐resolution USPIO magnetic resonance imaging at 4.7 T using novel phantom with minimal structural interference
Authors: Antell Henrik , Numminen Jussi , Abo‐Ramadan Usama , Niemelä Mika R. , Hernesniemi Juha A. , Kangasniemi Marko 
Published: October 2010

AbstractPurpose:To characterize the effect of ultrasmall superparamagnetic iron oxides (USPIOs) on magnetic resonance imaging (MRI) signal at 4.7 T, and to find the highest sensitivity pulse sequence for high‐resolution USPIO MRI.Materials and Methods:A novel phantom was constructed for optimization of sequence parameters for neuroradiological MR applications, and a wide range of dilutions of the USPIO ferumoxtran‐10 was imaged using T2/T1‐, T1‐, T2‐, T* 2‐, and PD‐weighted sequences. The effect of varying sequence parameters was investigated using phantom measurements and simulations.Results:The relaxivities r1, r2, and r*2 of ferumoxtran‐10 at 4.7 T (21°C) were 5.1, 82.2, and 148.4 mmol−1 L s−1, respectively. Gradient echo sequences produced superior susceptibility artifacts at high concentrations; susceptibility artifacts were seen down to a concentration of 137 nmol Fe/mL. A concentration of 17.5 μmol Fe/mL caused a signal void independently of sequence and parameters, and at concentrations ≤273 nmol Fe/mL no signal void was caused. Signal enhancement on T1‐weighted imaging was seen only at concentrations 137–547 nmol Fe/mL. For the same effective echo time T2‐weighted rapid acquisition with relaxation enhancement (RARE) yielded significantly higher contrast‐to‐noise ratio with RARE factor 16 than with RARE factor 8.Conclusion:At nanomolar concentrations of USPIO, steady‐state free precession offers an alternative to T2‐ and T* 2‐weighted sequences. Optimum parameters depend highly on USPIO concentration. J. Magn. Reson. Imaging 2010;32:1184–1196. © 2010 Wiley‐Liss, Inc.
Peripheral hyperintense pattern on T2‐weighted magnetic resonance imaging (MRI) in breast carcinoma: Correlation with early peripheral enhancement on dynamic MRI and histopathologic findings
Authors: Kawashima Hiroko , Kobayashi‐Yoshida Miki , Matsui Osamu , Zen Yoh , Suzuki Masayuki , Inokuchi Masafumi 
Published: October 2010

AbstractPurposeTo investigate the correlation between the peripheral hyperintense pattern of breast carcinoma on T2‐weighted images (T2WI) and the early peripheral enhancement (EPE) on dynamic magnetic resonance imaging (MRI) and to examine the histological characteristics involved in the causes thereof.Materials and MethodsThe signal intensity of 131 breast carcinomas of common type on T2WI was classified into four types and the correlations between the signal intensity and the histopathological subtypes were evaluated. We investigated correlation with the peripheral hyperintense pattern on a T2WI and other findings on MR images including EPE. In addition, we also investigated the histopathological characteristics in the lesions with a peripheral hyperintense pattern.ResultsThe signal intensities of the lesions on T2WI demonstrated hyperintensity, isointensity, hypointensity, and a peripheral hyperintense pattern in 26 (20%), 66 (50%), 19 (15%), and 20 (15%) lesions, respectively. A peripheral hyperintense pattern correlated with the appearance of EPE (P < 0.0001) and the degree of central fibrosis (P < 0.0001).ConclusionA peripheral hyperintense pattern on T2WI is a characteristic finding observed in breast carcinomas and correlated with the appearance of EPE. The appearance of a peripheral hyperintense pattern was affected by various histopathological features in the same manner as that observed for the formation of EPE. J. Magn. Reson. Imaging 2010;32:1117–1123. © 2010 Wiley‐Liss, Inc.
Real‐time diffusion‐perfusion mismatch analysis in acute stroke
Authors: Straka Matus , Albers Gregory W. , Bammer Roland 
Published: October 2010

AbstractDiffusion‐perfusion mismatch can be used to identify acute stroke patients that could benefit from reperfusion therapies. Early assessment of the mismatch facilitates necessary diagnosis and treatment decisions in acute stroke. We developed the RApid processing of PerfusIon and Diffusion (RAPID) for unsupervised, fully automated processing of perfusion and diffusion data for the purpose of expedited routine clinical assessment. The RAPID system computes quantitative perfusion maps (cerebral blood volume, CBV; cerebral blood flow, CBF; mean transit time, MTT; and the time until the residue function reaches its peak, Tmax) using deconvolution of tissue and arterial signals. Diffusion‐weighted imaging/perfusion‐weighted imaging (DWI/PWI) mismatch is automatically determined using infarct core segmentation of ADC maps and perfusion deficits segmented from Tmax maps. The performance of RAPID was evaluated on 63 acute stroke cases, in which diffusion and perfusion lesion volumes were outlined by both a human reader and the RAPID system. The correlation of outlined lesion volumes obtained from both methods was r2 = 0.99 for DWI and r2 = 0.96 for PWI. For mismatch identification, RAPID showed 100% sensitivity and 91% specificity. The mismatch information is made available on the hospital's PACS within 5–7 min. Results indicate that the automated system is sufficiently accurate and fast enough to be used for routine care as well as in clinical trials. J. Magn. Reson. Imaging 2010;32:1024–1037. © 2010 Wiley‐Liss, Inc.
Method for simultaneous voxel‐based morphometry of the brain and cervical spinal cord area measurements using 3D‐MDEFT
Authors: Freund Patrick A.B. , Dalton Catherine , Wheeler‐Kingshott Claudia A.M. , Glensman Janice , Bradbury David , Thompson Alan J. , Weiskopf Nikolaus 
Published: October 2010

AbstractPurposeTo investigate whether a 3D‐modified driven equilibrium Fourier transform (MDEFT)‐based acquisition protocol established for brain morphometry also yields reliable information about the cross‐sectional spinal cord area (SCA).Materials and MethodsImages of brain and cervical cord of 10 controls and eight subjects with spinal cord injury (SCI) were acquired with the 3D‐MDEFT‐based imaging protocol and an 8‐channel receive head coil. The new protocol was validated by two observers 1) comparing the SCA measured with the standard acquisition protocol (3D magnetization‐prepared rapid acquisition gradient echo [MPRAGE] and dedicated spine coil) and the new protocol; and 2) determining the scan–rescan reproducibility of the new protocol.ResultsScan–rescan reproducibility of SCA measurements with the MDEFT approach showed a similar precision for both observers with standard deviation (SD) <4.5 mm2 and coefficient of variation (CV) ≤5.1%. Analysis of variance (ANOVA) revealed a main effect of observer and interaction between observer and scan protocol that could be primarily attributed to a small observer bias for MPRAGE (difference in SCA <2.1 mm2). No bias was observed for 3D‐MDEFT vs. 3D‐MPRAGE.ConclusionThe 3D‐MDEFT method allows for robust unbiased assessment of SCA in addition to brain morphology. J. Magn. Reson. Imaging 2010;32:1242–1247. © 2010 Wiley‐Liss, Inc.
Fast algorithm for calculation of inhomogeneity gradient in magnetic resonance imaging data
Authors: Hui Cheukkai , Zhou Yu Xiang , Narayana Ponnada 
Published: October 2010

AbstractPurposeTo develop and implement a new approach for correcting the intensity inhomogeneity in magnetic resonance imaging (MRI) data.Materials and MethodsThe algorithm is based on the assumption that intensity inhomogeneity in MR data is multiplicative and smoothly varying. Using a statistically stable method, the algorithm first calculates the partial derivative of the inhomogeneity gradient across the data. The algorithm then solves for the gradient field and fits it to a parametric surface. It was tested on both simulated and real human and animal MRI data.ResultsThe algorithm is shown to restore the homogeneity in all images that were tested. On real human brain images the algorithm demonstrated superior or comparable performance relative to some of the commonly used intensity inhomogeneity correction methods such as SPM, BrainSuite, and N3.ConclusionThe proposed algorithm provides an alternative method for correcting the intensity inhomogeneity in MR images. It is shown to be fast and its performance is superior or comparable to algorithms described in the published literature. Due to its generality, this algorithm is applicable to MR images of both humans and animals. J. Magn. Reson. Imaging 2010;32:1197–1208. © 2010 Wiley‐Liss, Inc.
Local SAR reduction in parallel excitation based on channel‐dependent Tikhonov parameters
Authors: Cloos Martijn Anton , Luong Michel , Ferrand Guillaume , Amadon Alexis , Le Bihan Denis , Boulant Nicolas 
Published: October 2010

AbstractPurposeTo reduce the local specific absorption rate (SAR) obtained with tailored pulses using parallel transmission while obtaining homogenous flip angle distributions.Materials and MethodsFinite‐element simulations on a human head model were performed to obtain the individual magnetic and electric field maps for each channel of a parallel transmit array. From those maps, SAR calculations were carried out for “spoke” pulses designed to homogenize the flip angle in an axial slice of a human brain at 7 T. Based on the assumption that the coil element nearest to the maximum local energy deposition is the dominant contributor to the corresponding hot spot, a set of channel‐dependent Tikhonov parameters is optimized. Resulting SAR distributions are compared to the ones obtained when using standard pulse design approaches based on a single Tikhonov parameter.ResultsIn both the small‐ and large‐tip‐angle domain, the simulations show local SAR reductions by over a factor of 2 (4) for a well‐centered (off‐centered) head model at the expense of roughly 1% increment in flip‐angle spread over the slice.ConclusionSignificant SAR reductions can be obtained by optimizing channel‐dependent Tikhonov parameters based on the relation between coil elements and SAR hot spot positions. J. Magn. Reson. Imaging 2010;32:1209–1216. © 2010 Wiley‐Liss, Inc.
Semi‐automatic deformable registration of prostate MR images to pathological slices
Authors: Mazaheri Yousef , Bokacheva Louisa , Kroon Dirk‐Jan , Akin Oguz , Hricak Hedvig , Chamudot Daniel , Fine Samson , Koutcher Jason A. 
Published: October 2010

AbstractPurposeTo present a semi‐automatic deformable registration algorithm for co‐registering T2‐weighted (T2w) images of the prostate with whole‐mount pathological sections of prostatectomy specimens.Materials and MethodsTwenty‐four patients underwent 1.5 Tesla (T) endorectal MR imaging before radical prostatectomy with whole‐mount step‐section pathologic analysis of surgical specimens. For each patient, the T2w imaging containing the largest area of tumor was manually matched with the corresponding pathologic slice. The prostate was co‐registered using a free‐form deformation (FFD) algorithm based on B‐splines. Registration quality was assessed through differences between prostate diameters measured in right–left (RL) and anteroposterior (AP) directions on T2w images and pathologic slices and calculation of the Dice similarity coefficient, D, for the whole prostate (WP), the peripheral zone (PZ) and the transition zone (TZ).ResultsThe mean differences in diameters measured on pathology and MR imaging in the RL direction and the AP direction were 0.49 cm and −0.63 cm, respectively, before registration and 0.10 cm and −0.11 cm, respectively, after registration. The mean D values for the WP, PZ and TZ, were 0.76, 0.65, and 0.77, respectively, before registration and increased to 0.91, 0.76, and 0.85, respectively, after registration. The improvements in D were significant for all three tissues (P < 0.001 for all).ConclusionThe proposed semi‐automatic method enabled successful co‐registration of anatomical prostate MR images to pathologic slices. J. Magn. Reson. Imaging 2010;32:1149–1157. © 2010 Wiley‐Liss, Inc.
Myocardial T2* is not affected by ageing, myocardial fibrosis, or impaired left ventricular function
Authors: Kirk Paul , Smith Gillian C. , Roughton Michael , He T. , Pennell Dudley J. 
Published: October 2010

AbstractPurposeTo evaluate the influence of alterations in myocardial structure and function from increasing age, myocardial fibrosis, or impaired left ventricular function on myocardial T2*.Materials and MethodsMyocardial T2* was measured in 126 subjects without cardiac iron loading, of whom 63 were normals of varying ages, 39 were patients with impaired left ventricular function from various nonsiderotic cardiac causes, and 24 were patients with chronic myocardial infarction affecting the interventricular septum (where myocardial T2* measurements are normally made).ResultsThe median (Q1, Q3) of myocardial T2* in the normals was 36.3 ms (31.6, 45.4). There was no significant correlation between myocardial T2* and age (R2 = 0.04; P = 0.11). In the patients with impaired left ventricular function, the median myocardial T2* was 35.5 ms (31, 42.2) (P = 0.34 versus normals). There was no significant correlation between ejection fraction and T2* in patients with left ventricular impairment (R2 = 0.03; P = 0.33). In the patients with septal infarction, the median septal myocardial T2* was 35.4 ms (32.7, 43) (P = 0.81 vs normals).ConclusionThere was no significant change in myocardial T2* associated with any alterations of myocardial structure and function occurring with increasing age, impairment of left ventricular function or septal fibrosis from chronic myocardial infarction. These results indicate that myocardial T2* measurements are robust to these potential confounding parameters. J. Magn. Reson. Imaging 2010;32:1095–1098. © 2010 Wiley‐Liss, Inc.
Combined off‐resonance imaging and T2 relaxation in the rotating frame for positive contrast MR imaging of infection in a murine burn model
Authors: Andronesi Ovidiu C. , Mintzopoulos Dionyssios , Psychogios Nikolaos , Kesarwani Meenu , He Jianxin , Yasuhara Shingo , Dai George , Rahme Laurence G. , Tzika Aria A. 
Published: October 2010

AbstractPurposeTo develop novel magnetic resonance (MR) imaging methods to monitor accumulation of macrophages in inflammation and infection. Positive‐contrast MR imaging provides an alternative to negative‐contrast MRI, exploiting the chemical shift induced by ultra‐small superparamagnetic iron‐oxide (USPIO) nanoparticles to nearby water molecules. We introduce a novel combination of off‐resonance (ORI) positive‐contrast MRI and T2ρ relaxation in the rotating frame (ORI‐T2ρ) for positive‐contrast MR imaging of USPIO.Materials and MethodsWe tested ORI‐T2ρ in phantoms and imaged in vivo the accumulation of USPIO‐labeled macrophages at the infection site in a mouse model of burn trauma and infection with Pseudomonas aeruginosa (PA). PA infection is clinically important. The USPIO nanoparticles were injected directly in the animals in solution, and macrophage labeling occurred in vivo in the animal model.ResultsWe observed a significant difference between ORI‐T2ρ and ORI, which leads us to suggest that ORI‐T2ρ is more sensitive in detecting USPIO signal. To this end, the ORI‐T2ρ positive contrast method may prove to be of higher utility in future research.ConclusionOur results may have direct implications in the longitudinal monitoring of infection, and open perspectives for testing novel anti‐infective compounds. J. Magn. Reson. Imaging 2010;32:1172–1183. © 2010 Wiley‐Liss, Inc.
Screening for embryonic loss during in utero development of mice with a human 1.5 Tesla clinical MRI scanner
Authors: Gruemmer Ruth , Maderwald Stefan , Winterhager Elke , Hauth Elke 
Published: October 2010

AbstractPurposeTo establish in utero MRI‐scanning of mouse implantation sites in a 1.5 Tesla whole‐body human clinical scanner for evaluation of impaired implantation, placental or developmental defects due to genetic alterations.Materials and MethodsPregnant C57Bl/6 wild‐type and Cx31‐deficient mice revealing placental defects were analyzed in utero using a 1.5 Tesla whole‐body clinical scanner in combination with a 3‐cm‐diameter single loop (slice thickness: 1.2 mm). Imaging of implantation sites was evaluated from 6.5–13.5 dpc and amount of implantation sites and in vivo development was analyzed during the critical phase of placentation from 10.5–13.5 dpc.ResultsThis method provided high resolution in plane images permitting confident identification of all implantation sites from 6.5 dpc onward. A loss of 60% of Cx31‐deficient embryos was demonstrated compared with controls. Repeated anesthesia as well as imaging protocols produced no gross malformations in the surviving mice.ConclusionUsing a human clinical MRI scanner high resolution imaging of the entire uterus of the mice and all the embryos inside could be performed. This method is well suited to noninvasively monitor and quantify embryo implantation and to follow this dynamic process in vivo without compromising pregnancy progression and embryonic development. J. Magn. Reson. Imaging 2010;32:1158–1165. © 2010 Wiley‐Liss, Inc.
In vivo MR imaging tracking of transplanted mesenchymal stem cells in a rabbit model of acute peripheral nerve traction injury
Authors: Shen Jun , Duan Xiao‐Hui , Cheng Li‐Na , Zhong Xiao‐Mei , Guo Ruo‐Mi , Zhang Fang , Zhou Cui‐Ping , Liang Bi‐Ling 
Published: October 2010

AbstractPurposeTo investigate in vivo MRI tracking mesenchymal stem cells (MSCs) in peripheral nerve injures using a clinically available paramagnetic contrast agent (Gd‐DTPA) and commercially available rhodamine‐incorporated transfection reagents (PEI‐FluoR).Materials and MethodsAfter bone marrow MSCs were labeled with Gd‐DTPA and PEI‐FluoR complex, the labeling efficacy and longevity of Gd‐DTPA maintenance were measured and cell viability, proliferation, and apoptosis were assessed. Thirty‐six rabbits with acute sciatic nerve traction injury randomly received 1 × 106 labeled (n = 12) or unlabeled MSCs (n = 12) or vehicle alone injection. The distribution and migration of implanted cells was followed by MRI and correlated with histology. The relative signal intensity (RSL) of the grafts was measured.ResultsThe labeling efficiency was 76 ± 4.7% and the labeling procedure did not inﬂuence cell viability, proliferation, and apoptosis. A persistent higher RSL in grafts was found in the labeled group compared with the unlabeled and vehicle groups until 10 days after transplantation (P < 0.05). The distribution and migration of labeled cells could be tracked by MRI until 10 days after transplantation. Transplanted MSCs were not found to transdifferentiate into Schwann‐like cells within 14‐day follow‐up.ConclusionLabeling MSCs with the dual agents may enable cellular MRI of the engraftment in the experimental peripheral nerve injury. J. Magn. Reson. Imaging 2010;32:1076–1085. © 2010 Wiley‐Liss, Inc.