bluuebunny/crossref_metadata_2025 huggingface dataset:
Changing the criteria for old/new recognition judgments can modulate activity in the anterior hippocampus
Authors: Hashimoto Ryusaku , Abe Nobuhito , Ueno Aya , Fujii Toshikatsu , Takahashi Shoki , Mori Etsuro
Published: September 2010

Numerous functional magnetic resonance imaging (fMRI) studies have reported that the medial temporal lobe (MTL) is activated to a greater extent when subjects encounter novel items as compared with familiar ones. However, it remains unclear whether the novelty signals in the MTL are modulated by the criteria for old/new recognition judgments. In this study, we used fMRI to test our hypothesis that when subjects encounter items similar to previously encountered ones, the novelty signals in the MTL will differ depending on whether the subjects focus on the perceptual features or the semantic aspects of the items. The subjects studied a series of photographs and were later asked to make a recognition judgment of (a) Same items (items identical to those seen during encoding), (b) Similar items (items similar to but not identical to those seen during encoding), and (c) New items (unstudied items) in two types of tasks: Perceptual and Semantic. The subjects judged whether the items were perceptually identical to those seen during encoding in the Perceptual task and whether the items were semantically identical to those seen during encoding in the Semantic task. The left anterior hippocampus was activated when subjects were presented with New items relative to Same items in both tasks. In addition, the hippocampal activity in response to the Similar items was increased only in the Perceptual, but not the Semantic task. Our results indicate that the novelty signals in the hippocampus can be modulated by criteria for old/new recognition judgments. © 2010 Wiley Periodicals, Inc.
Conquering cancer through discovery research
Authors: Cho William C. S.
Published: September 2010

Cancer is a leading cause of death worldwide. Cancer research improves our understanding of cancer biology, which leads to the discoveries of novel detection approaches and effective therapies for cancer. Translational cancer medicine changes essential science breakthroughs to the practice of medicine and uses clinical result to supply back into basic research. This article covers some studies in the field of translational cancer medicine including the identification of 319 driver genes and the 12 core cancer pathways, the use of MammaPrint in breast cancer, the development of OncoMap, the progress in genome‐wide association studies, as well as the generation of microRNA networks in cancer and leukemia. Apart from cancer genome, cancer stem cells, immune and tumor microenvironment are also discussed. In addition, some innovations in translational cancer medicine are introduced. A number of targeted agents have been developed, such as the histone deacetylases inhibitors, poly(ADP‐ribose) polymerase inhibitors, anti‐mammalian target of rapamycin agents, and PI3K pathway inhibitors. There are also reports of the results from some important clinical trials, including the STAR P‐2 trial, NeoBIG program, and BATTLE trial. This review focuses on discussions that emphasize the marriage between curiosity‐driven basic research and patient care‐focused clinical investigations. With highlights on the most up‐to‐date molecular, cellular, clinical, and therapeutic cancer research findings, this article tends to provide a wealth of insights into better understanding of the complexity of cancer. © 2010 IUBMB IUBMB Life, 62(9): 655–659, 2010
Amino acid ingestion and glucose metabolism—A review
Authors: Gannon Mary C. , Nuttall Frank Q.
Published: September 2010

Interest in the effect of proteins or amino acids on glucose metabolism dates back at least a century, largely because it was demonstrated that the amino acids from ingested protein could be converted into glucose. Indeed, these observations influenced the dietary information provided to people with diabetes. Subsequently it was shown that ingested protein did not raise the blood glucose concentration. It also was shown that proteins could stimulate a rise in insulin and glucagon but the response to various proteins was different. In addition, it was shown that individual amino acids also could stimulate a rise in insulin and in glucagon concentrations. When individual amino acids are ingested by normal subjects, there is an ordering of the insulin and glucagon responses. However, the order is not the same for insulin and glucagon. In addition, the metabolic response cannot be predicted based on the functional groups of the amino acids. Thus, empirical prediction of the metabolic response to ingested single amino acids is not possible. © 2010 IUBMB IUBMB Life, 62(9): 660–668, 2010
3 Tesla and 7 Tesla MRI of multiple sclerosis cortical lesions
Authors: Tallantyre Emma C. , Morgan Paul S. , Dixon Jennifer E. , Al‐Radaideh Ali , Brookes Matthew J. , Morris Peter G. , Evangelou Nikos
Published: September 2010

Cortical lesions are prevalent in multiple sclerosis but are poorly detected using MRI. The double inversion recovery (DIR) sequence is increasingly used to explore the clinical relevance of cortical demyelination. Here we evaluate the agreement between imaging sequences at 3 Tesla (T) and 7T for the presence and appearance of individual multiple sclerosis cortical lesions. Eleven patients with demyelinating disease and eight healthy volunteers underwent MR imaging at 3T (fluid attenuated inversion recovery [FLAIR], DIR, and T1‐weighted magnetization prepared rapid acquisition gradient echo [MP‐RAGE] sequences) and 7T (T1‐weighted MP‐RAGE). There was good agreement between images for the presence of mixed cortical lesions (involving both gray and white matter). However, agreement between imaging sequences was less good for purely intracortical lesions. Even after retrospective analysis, 25% of cortical lesions could only be visualized on a single MRI sequence. Several DIR hyperintensities thought to represent cortical lesions were found to correspond to signal arising from extracortical blood vessels. High‐resolution 7T imaging appeared useful for confidently classifying the location of lesions in relation to the cortical/subcortical boundary. We conclude that DIR, FLAIR, and MP‐RAGE imaging sequences appear to provide complementary information during the detection of multiple sclerosis cortical lesions. High resolution 7T imaging may facilitate anatomical localization of lesions in relation to the cortical boundary. J. Magn. Reson. Imaging 2010;32:971–977. © 2010 Wiley‐Liss, Inc.
T1ρ and T2 quantitative magnetic resonance imaging analysis of cartilage regeneration following microfracture and mosaicplasty cartilage resurfacing procedures
Authors: Holtzman Daniel J , Theologis Alexander A , Carballido‐Gamio Julio , Majumdar Sharmila , Li Xiaojuan , Benjamin C.
Published: September 2010

Purpose

To examine T1ρ (T1rho) and T2 quantitative magnetic resonance imaging (MRI) in evaluating cartilage regeneration following microfracture (MFx) and mosaicplasty (MOS) cartilage resurfacing procedures.

Materials and Methods

Eighteen patients underwent MFx and eight patients underwent MOS to treat symptomatic focal cartilage defects. Quantitative T1ρ and T2 maps were acquired at 3–6 months and 1 year after surgery. The area of resurfacing was identified, and T1ρ and T2 values for the regenerated tissue (RT) and normal cartilage (NC) were acquired. RT/NC ratios were calculated to standardize absolute T1ρ and T2 values. Data were prospective, cross‐sectional, and nonrandomized.

Results

T1ρ and T2 showed good reanalysis reproducibility for RT and NC. Significant differences between RT and NC were present following MFx at 3–6 months for T1ρ and T2 values as well as following MOS at 3–6 months and 1 year for T1ρ values. Following MFx, the T2 RT/NC ratio was significantly different between 3–6 months and 1 year (P = 0.02), while the T1ρ RT/NC ratio approached significance (P = 0.07). Following MOS, the T1ρ and T2 RT/NC ratios were not significantly different between the two timepoints.

Conclusion

T1ρ and T2 MRI are complementary and reproducible methods for quantitatively and noninvasively monitoring regeneration of RT following MFx and MOS. J. Magn. Reson. Imaging 2010;32:914–923. © 2010 Wiley‐Liss, Inc.
Quantitative cerebral MR perfusion imaging: Preliminary results in stroke
Authors: Shah Maulin K. , Shin Wanyong , Parikh Vishal S. , Ragin Ann , Mouannes Jessy , Bernstein Richard A. , Walker Matthew T. , Bhatt Hem , Carroll Timothy J.
Published: September 2010

Purpose

To evaluate quantitative cerebral blood flow (qCBF) with traditional time‐based measurements or metrics of cerebral perfusion: time to peak (Tmax) and mean transit time (MTT) in stroke patients.

Materials and Methods

Nine ischemic stroke patients (four male, five female, 63 ± 16 years old) were included in the study which was Health Insurance Portability and Accountability Act compliant and institutional review board approved. Cerebral perfusion was quantified using the Bookend method. Mean values of qCBF, Tmax, and MTT were determined in regions of interest (ROIs). ROIs were drawn on diffusion weighted images in diffusion positive, critically ischemic (CI), in ipsilateral normal region immediately surrounding the critically ischemic region, the presumed penumbra (PP), and in contralateral diffusion negative control, presumed normal region (PN) of gray and white matter separately (GM and WM).

Results

In both GM and WM, qCBF measures distinguished the studied brain regions with the most markedly reduced values in regions corresponding to extent of likely ischemic injury. In planned comparisons, only qCBF measurements differed significantly between CI and PP tissues. ROC analysis supported the utility of qCBF for discriminating brain regions differing in the likely extent of ischemic injury (CI and PN regions – qCBF: area under the curve [AUC] = 0.96, Tmax: AUC = 0.96, MTT: AUC = 0.72). Importantly, qCBF afforded the best discrimination of CI and PP regions (qCBF: AUC = 0.82, Tmax: AUC = 0.65, MTT: AUC = 0.52).

Conclusion

This initial evaluation indicates that quantitative MRI perfusion is feasible in ischemic stroke patients. qCBF derived with this strategy provide enhanced discrimination of CI and PP compared to time‐based imaging metrics. This approach merits investigation in larger clinical studies. J. Magn. Reson. Imaging 2010;32:796–802. © 2010 Wiley‐Liss, Inc.
Predicting survival in glioblastomas using diffusion tensor imaging metrics
Authors: Saksena Sona , Jain Rajan , Narang Jayant , Scarpace Lisa , Schultz Lonni R. , Lehman Norman L. , Hearshen David , Patel Suresh C. , Mikkelsen Tom
Published: September 2010

Purpose

To retrospectively correlate various diffusion tensor imaging (DTI) metrics in patients with glioblastoma multiforme (GBM) with patient survival analysis and also degree of tumor proliferation index determined histologically.

Materials and Methods

Thirty‐four patients with histologically confirmed treatment naive GBMs underwent DTI on a 3.0 Tesla (T) scanner. Region‐of‐interest was placed on the whole lesion including the enhancing as well as nonenhancing component of the lesion to determine the various DTI metrics. Kaplan‐Meier estimates and Cox proportional hazards regression methods were used to assess the relationship of DTI metrics (minimum and mean values) and Ki‐67 with progression free survival (PFS). To study the relationship between DTI metrics and Ki‐67, Pearson's correlation coefficient was computed.

Results

Univariate analysis showed that patients with fractional anisotropy (FA)mean ≤ 0.2, apparent diffusion coefficient (ADC)min ≤ 0.6, planar anisotropy (CP)min ≤ 0.002, spherical anisotropy (CS)mean > 0.68 and Ki‐67 > 0.3 had lower PFS rate. The multivariate analysis demonstrated that only CPmin was the best predictor of survival in these patients, after adjusting for age, Karnofsky performance scale and extent of resection. No significant correlation between DTI metrics and Ki‐67 were observed.

Conclusion

DTI metrics can be used as a sensitive and early indicator for PFS in patients with glioblastomas. This could be useful for treatment planning as high‐grade gliomas with lower ADCmin, FAmean, CPmin, and higher CSmean values may be treated more aggressively. J. Magn. Reson. Imaging 2010;32:788–795. © 2010 Wiley‐Liss, Inc.
Comparison of segmentation methods for MRI measurement of cardiac function in rats
Authors: Riegler Johannes , Cheung King K. , Man Yiu Fung , Cleary Jon O. , Price Anthony N. , Lythgoe Mark F.
Published: September 2010

Purpose

To establish the accuracy, intra‐ and inter‐observer variabilities of four different segmentation methods for measuring cardiac functional parameters in healthy and infarcted rat hearts.

Materials and Methods

Six Wistar rats were imaged before and after myocardial infarction using an electrocardiogram and respiratory‐gated spoiled gradient echo sequence. Blinded and randomized datasets were analyzed by various semi‐automatic and manual segmentation methods to compare their measurement bias and variability. In addition, the accuracy of these methods was assessed by comparison with reference measurements acquired from high‐resolution three‐dimensional (3D) datasets of a heart phantom.

Results

Relative inter‐ and intra‐observer variability were found to be similar for all four methods. Semi‐automatic segmentation methods reduced analysis time by up to 70%, while yielding similar measurement bias and variability compared with manual segmentation. Semi‐automatic methods were found to underestimate the ejection fraction for healthy hearts compared with manual segmentation while overestimating them in infarcted hearts. However, semi‐automatic segmentation of short axis slices agreed better with 3D reference scans of a heart phantom compared with manual segmentation.

Conclusion

Semi‐automatic segmentation methods are faster than manual segmentation, while offering a similar intra‐ and inter‐observer variability. However, a potential bias has been observed between healthy and infarcted hearts for different methods, which should also be considered when selecting the most appropriate analysis technique. J. Magn. Reson. Imaging 2010;32:869–877. © 2010 Wiley‐Liss, Inc.
Longitudinal and multi‐echo transverse relaxation times of normal breast tissue at 3 Tesla
Authors: Edden Richard A.E. , Smith Seth A. , Barker Peter B.
Published: September 2010

Purpose

To measure longitudinal (T1) and multi‐echo transverse (T2) relaxation times of healthy breast tissue at 3 Tesla (T).

Materials and Methods

High‐resolution relaxation time measurements were made in six healthy female subjects. Inversion recovery images were acquired at 10 inversion times between 100 ms and 4000 ms, and multiple spin echo images were acquired at 16 echo times between 10 ms and 160 ms.

Results

Longitudinal relaxation times T1 were measured as 423 ± 12 ms for adipose tissue and 1680 ± 180 ms for fibroglandular tissue. Multi‐echo transverse relaxation times T2 were measured as 154 ± 9 ms for adipose tissue and 71 ± 6 ms for fibroglandular tissue. Histograms of the voxel‐wise relaxation times and quantitative relaxation time maps are also presented.

Conclusion

T1 and multi‐echo T2 relaxation times in normal human breast tissue are reported. These values are useful for pulse sequence design and optimization for 3T breast MRI. Compared with the literature, T1 values are significantly longer at 3T, suggesting that longer repetition time and inversion time values should be used for similar image contrast. J. Magn. Reson. Imaging 2010;32:982–987. © 2010 Wiley‐Liss, Inc.
Role of neuroimaging in promoting long‐term recovery from ischemic stroke
Authors: Seitz Rüdiger J. , Donnan Geoffrey A.
Published: September 2010

Human ischemic stroke is an acute disorder followed by a recovery period which may be of varying duration and mechanism. Imaging has created a means to explore the stroke process in vivo, particularly its underlying pathophysiology and recovery mechanisms. Evidence from multicenter studies has shown that, in the acute phase, arterial recanalization and reperfusion of ischemic brain tissue are the most important determinants of recovery. This is followed by functional and structural changes in the perilesional tissue and in large‐scale bihemispheric networks that continue with different dynamics for weeks to months. Proof‐of‐principle studies have revealed that the behavioral gains induced by rehabilitation are paralleled by changes in functional representations. This is supported by data from neuroimaging and electrophysiological studies early after stroke which have shown that dedicated training can induce changes in cerebral functional representations. Accordingly, there is clear evidence that neuroimaging has a significant potential for monitoring the hemodynamic, functional, and structural factors determining recovery from stroke. New imaging methods may provide relevant biomarkers for treatment decisions and therapeutic monitoring. By combining neuroimaging with electrophysiological measures, opportunities exist to develop neuroscience‐based strategies in rehabilitation. J. Magn. Reson. Imaging 2010;32:756–772. © 2010 Wiley‐Liss, Inc.
Characterization of cirrhotic nodules with gadoxetic acid‐enhanced magnetic resonance imaging: The efficacy of hepatocyte‐phase imaging
Authors: Chou Chen‐Te , Chen Yao‐Li , Su Wei‐Wen , Wu Hwa‐Koon , Chen Ran‐Chou
Published: September 2010

Purpose

To evaluate the efficacy of hepatocyte‐phase imaging (HP) in characterization of focal hepatic lesions in cirrhotic liver using gadoxetic acid‐enhanced magnetic resonance imaging (MRI).

Methods

A total of 66 nodules of 38 patients with liver cirrhosis undergoing gadoxetic acid‐enhanced MRI were prospectively enrolled in this study. The histological examination revealed 15 dysplastic nodules (DNs), 7 well‐differentiated hepatocellular carcinomas (wHCCs), and 44 moderately differentiated HCCs (mHCCs). Two imaging sets (Set A without HP, Set B with HP) were prepared to evaluate the efficacy of HP in lesion characterization.

Results

The mean enhancement ratios (ERs) of mHCC were significantly increased in arterial phase followed by a subsequent decreased in hepatocyte phases. The mean ERs of wHCC were increased in dynamic study and followed by a plateau in the hepatocyte phase. The mean ERs of DNs were increased in dynamic study and hepatocyte phase. The mean liver‐to‐lesion contrasts of mHCCs were increased in arterial phase and HP (P < 0.05). wHCCs were only increased in HP (P < 0.05). DNs showed no significant difference in any phase (P > 0.05). There were seven additional HCCs that were detected in HP using imaging Set B compared to Set A. The diagnostic performance of Set B was significantly higher than that of Set A (P = 0.016).

Conclusion

The combination of gadoxetic acid‐enhanced dynamic study and hepatocyte‐phase T1WI may provide better diagnostic performance than only dynamic study in characterization of focal lesions in cirrhotic liver. J. Magn. Reson. Imaging 2010;32:895–902. © 2010 Wiley‐Liss, Inc.
Measurement of gas transport kinetics in high‐frequency oscillatory ventilation (HFOV) of the lung using hyperpolarized 3He magnetic resonance imaging
Authors: Terekhov Maxim , Rivoire Julien , Scholz Alexander , Wolf Ursula , Karpuk Sergei , Salhi Zahir , Koebrich Rainer , David Matthias , Schreiber Laura Maria
Published: September 2010

Purpose

To protect the patient with acute respiratory distress syndrome from ventilator associated lung injury (VALI) high‐frequency oscillatory ventilation (HFOV) is used. Clinical experience has proven that HFOV is an efficient therapy when conventional artificial ventilation is insufficient. However, the optimal settings of HFOV parameters, eg, tidal volumes, pressure amplitudes and frequency for maximal lung protection, and efficient gas exchange are not established unambiguously.

Methods

In this work magnetic resonance imaging (MRI) with hyperpolarized 3He was employed to visualize the redistribution of gas within the cadaver pig lung during HFOV. The saturated slice method was used to characterize fast gas kinetics.

Results

The strong differences in kinetics were observed for HFOV‐driven gas exchange in comparison with diffusive gas transport (apnea). The significant regional and HFOV frequency dependence was detected for washout and gas exchange within the lungs. Gas redistribution was much faster in posterior than in anterior parts of the lungs during HFOV, in contrast to minor differences with an opposite trend observed in apnea.

Conclusion

The method shows significant potential for visualization and quantification of gas redistribution under HFOV and may help in optimization of the parameters to improve the clinical effect of HFOV for patients. J. Magn. Reson. Imaging 2010;32:887–894. © 2010 Wiley‐Liss, Inc.
Diffusion tensor tractography demonstration of partially injured spinal cord tracts in a patient with posttraumatic brown sequard syndrome
Authors: Rajasekaran Shanmughanathan , Kanna Rishi Mugesh , Karunanithi Rajamanickam , Shetty Ajoy Prasad
Published: September 2010

The authors report the utility of diffusion tensor tractography in demonstrating the partially severed spinal cord tracts on one side with normal, intact, distally traceable tracts on the opposite side in a patient with posttraumatic Brown Sequard syndrome. A 30‐year‐old man presented with typical clinical features of a hemisection injury of the thoracic spinal cord, 2 months after he had sustained a back stab injury. Routine MRI showed T2 hyperintense zones in the thoracic spinal cord at the level of T5. We did axial single shot echo planar diffusion tensor imaging with a 1.5 Tesla MR machine. Tractography effectively depicted the injured spinal cord tracts on the left side with normal intact tracts on the right side, which could be traced distally. The fractional anisotropy and apparent diffusion coefficient values showed significant changes at the level of injury. Tractographic demonstration of human spinal cord injury is reported for the first time. J. Magn. Reson. Imaging 2010;32:978–981. © 2010 Wiley‐Liss, Inc.
Dynamic susceptibility contrast perfusion weighted imaging in grading of nonenhancing astrocytomas
Authors: Morita Naomi , Wang Sumei , Chawla Sanjeev , Poptani Harish , Melhem Elias R.
Published: September 2010

Purpose

To evaluate if the relative tumor blood volume (rTBV) using dynamic susceptibility contrast magnetic resonance imaging (DSC‐MRI) can aid in distinguishing low‐ from high‐grade nonenhancing astrocytomas.

Materials and Methods

Seventeen patients with histologically proven astrocytomas underwent MRI including DSC‐MRI. Maximum TBV regions of interest were recorded from each neoplasm and normalized to contralateral normal white matter. Demographic features, diagnostic MRI findings including tumor volumes, and the normalized rTBV ratios were compared between low‐grade (I and II, LGA, n = 6) and high‐grade (III) astrocytomas (HGA, n = 11) using Mann–Whitney's U‐test and receiver operating characteristic (ROC) analysis.

Results

Maximum rTBV ratios were statistically higher for HGA (1.11 ± 0.13) than LGA (0.66 ± 0.17, P < 0.005) with the best cutoff threshold at 0.94 (sensitivity of 90.9%, specificity of 100%). Differences in mean age and tumor volume on fluid‐attenuated inversion recovery (FLAIR) imaging between the two groups did not reach statistical difference (P = 0.22, 0.36).

Conclusion

The addition of DSC‐MRI can aid in accurate grading of nonenhancing astrocytomas with high sensitivity and specificity. J. Magn. Reson. Imaging 2010;32:803–808. © 2010 Wiley‐Liss, Inc.
Late gadolinium enhancement of acute myocardial infarction in mice at 7T: Cine‐FLASH versus inversion recovery
Authors: Protti Andrea , Sirker Alexander , Shah Ajay M. , Botnar Rene
Published: September 2010

Purpose

To investigate myocardial infarction (MI), late gadolinium (Gd) enhancement (LGE), cardiovascular magnetic resonance imaging (CMRI) is used as the current gold standard for the in vivo diagnosis in patients and preclinical studies. While inversion recovery (IR) fast gradient echo LGE imaging is the preferred technique at clinical field strengths it remains to be investigated which is the best sequence at higher field strength. We therefore compared the IR technique against cine fast low shot angle (cine‐FLASH) for the quantification of MI size in mice at 7T in vivo.

Materials and Methods

Five mice were used to optimize cine‐FLASH and IR parameters. Nine mice were subsequently imaged with optimized parameters using both techniques 2–3 days after MI and ≈30 minutes post Gd injection.

Results

The difference in infarct size values was within 3.3% between the two CMRI techniques and within 7.5% of histological values by Bland–Altman analysis. Contrast‐to‐noise‐ratio between infarcted and normal tissue as well as blood was higher for cine‐FLASH with the additional benefit of a 2‐time‐fold shorter scan time than with the IR method. Furthermore, left ventricular function/volumes could be calculated from cine‐FLASH images before as well as after Gd injection.

Conclusion

In conclusion, cine‐FLASH LGE MRI represents an attractive alternative to IR LGE MRI for infarct size assessment in mice at high field strengths because it provides similar accuracy while being more robust, faster, and less user dependent. J. Magn. Reson. Imaging 2010;32:878–886. © 2010 Wiley‐Liss, Inc.
Mixed‐bandwidth acquisitions: Signal‐to‐noise ratio and signal‐to‐noise efficiency
Authors: Choli Morwan , Jakob Peter M. , Loeffler Ralf B. , Hillenbrand Claudia M.
Published: September 2010

Purpose

To evaluate signal‐to‐noise ratio (SNR) and SNR efficiency in mixed‐bandwidth acquisition (MBA). SNR efficiency describes the achievable SNR per unit time and is a basic aspect in clinical applications to optimize work flow.

Materials and Methods

Corresponding simulations were performed and predictions of the theory verified in phantom experiments and volunteers. Specifically, SNR and SNR efficiencies were compared for an MBA fast low‐angle shot (MBA‐FLASH) sequence and traditional single‐bandwidth acquisitions.

Results:

MBAs result in an SNR penalty compared to single‐bandwidth acquisitions for a given sampling time. Furthermore, the nonuniform distribution of noise characteristics in k‐space introduced by MBA sequences caused potential changes in noise texture of the image.

Conclusion

Overall, the MBA‐FLASH imaging experiments in phantoms and healthy volunteers support the feasibility of using dual or multiple bandwidth acquisitions, which may be important in alternative imaging schemes that combine multiple acquisition techniques. J. Magn. Reson. Imaging 2010;32:997–1002. © 2010 Wiley‐Liss, Inc.
Diffusion tensor tractography of the human brain cortico‐ponto‐cerebellar pathways: A quantitative preliminary study
Authors: Kamali Arash , Kramer Larry A. , Frye Richard E. , Butler Ian J , Hasan Khader M.
Published: September 2010

Purpose

To investigate the utility of diffusion tensor tractography at 1mm slice thickness to map and quantify the whole trajectory of different cortico‐ponto‐cerebellar pathways of the healthy adult human brain.

Materials and Methods

This work was approved by the local Institutional Review Board, and was Health Insurance Portability and Accountability Act (HIPAA) compliant. Five healthy right‐handed men (age range, 24–37 years) were studied and written informed consent was obtained. Diffusion tensor imaging data acquired with 1‐mm slice thickness at a 3.0 Tesla (T) clinical MRI scanner were prepared and analyzed using tractography methods to reconstruct the cortico‐ponto‐cerebellar pathways which included the fronto‐ponto‐cerebellar, parieto‐ponto‐cerebellar, occipito‐ponto‐cerebellar, and temporo‐ponto‐cerebellar tracts.

Results

We demonstrate the feasibility of tractographic mapping and quantification of the four cortico‐ponto‐cerebellar system components based on their cortical connections in the healthy human brain using DTI data with thin 1‐mm sections.

Conclusion

In vivo quantification of different cortico‐ponto‐cerebellar pathways based on cortical connection is feasible, using 1‐mm slices at 3.0T. J. Magn. Reson. Imaging 2010;32:809–817. © 2010 Wiley‐Liss, Inc.
Comparison of enhancement patterns of histologically confirmed hepatocellular carcinoma between gadoxetate‐ and ferucarbotran‐enhanced magnetic resonance imaging
Authors: Okada Masahiro , Imai Yasuharu , Kim Tonsok , Kogita Sachiyo , Takamura Manabu , Kumano Seishi , Onishi Hiromitsu , Hori Masatoshi , Fukuda Kazuto , Hayashi Norio , Wakasa Kenichi , Sakamoto Michiie , Murakami Takamichi
Published: September 2010

Purpose

To compare enhancenent patterns of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) between gadoxetate‐ and ferucarbotran‐enhanced MRI.

Materials and Methods

Patients recruited from ultrasound surveillance for HCC in chronic liver diseases were enrolled in this prospective study approved by institutional review board. Thirty‐six patients with 37 histologically proven HCC, including 22 well‐differentiated HCCs (wHCC), 15 moderately to poorly differentiated HCCs (mpHCCs), and 4 DNs, underwent gadoxetate‐enhanced and ferucarbotran‐enhanced MRI. We compared hepatobiliary phase image of gadoxetate‐enhanced MRI with ferucarbotran‐enhanced MR image regarding signal intensity of HCC and DN relative to surrounding liver parenchyma. We calculated contrast ratios between tumor and liver on pre‐enhancement, hepatobiliary phase of gadoxetate‐enhanced MRI and ferucarbotran‐enhanced MRI.

Results

On ferucarbotran‐enhanced MRI, all mpHCCs showed hyper‐intensity, while 14 wHCCs (14/22;63%) showed iso‐intensity. On hepatobiliary phase of gadoxetate‐enhanced MRI, 13 mpHCCs (13/15;86%) and 20 wHCCs (20/22;91%) showed hypo‐intensity. Two DNs and the other two showed iso‐ and hypo‐intensity, respectively, on gadoxetate‐enhanced MRI, whereas all DNs revealed iso‐intensity on ferucarbotran‐enhanced MRI. Gadoxetate‐postcontrast ratio was significantly lower than ferucarbotran‐postcontrast ratio in wHCC (P = 0.015).

Conclusion

The uptake function of hepatocytes that are targeted by gadoxetate is more sensitive than that of Kupffer cells targeted by ferucarbotran in stepwise hepatocarcinogenesis. J. Magn. Reson. Imaging 2010;32:903–913. © 2010 Wiley‐Liss, Inc.
Single‐dose time‐resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: Compared with digital subtraction angiography
Authors: Wang Chun‐Chieh , Liang Huei‐Lung , Hsiao Chia‐Chi , Chen Matt Chiung‐Yu , Wu To‐Ho , Wu Chieh‐Jen , Huang Jer‐Shyung , Lin Yih‐Huei , Pan Huay‐Ben
Published: September 2010

Purpose

To prospectively study the diagnostic performance of hybrid single‐dose contrast‐enhanced MRA of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the reference standard.

Materials and Methods

Hybrid MRA, combining time resolved imaging of contrast kinetics and two‐station bolus‐chase sequences, of lower limb was performed in 31 PAD patients (21 men, 10 women; mean age, 72 years) with two separate gadobenate dimeglumine (8 mL) injections in each sequence. Two independent blinded readers analyzed the vascular stenosis (32 segments in each limb). Sensitivity, specificity, and accuracy in all vascular segments and segments below popliteal artery were calculated. Interobserver agreements on MRA and intermodality agreements between MRA and DSA were calculated by using k statistics.

Results

Sensitivity, specificity, and accuracy of the hybrid MRA with regard to hemodynamically significant stenosis in all vascular segments were 92%, 97%, and 95% for reader 1, and 90%, 92%, and 92%, for reader 2, respectively. The interobsever agreements on MRA were good (k = 0.77–0.74) for all‐grade stenosis, and excellent (k = 0.82–0.81) for hemadynamically significant stenosis. The intermodality agreements are good to excellent (k = 0.73–0.94).

Conclusion

Single‐dose hybrid MRA is a safe and reliable noninvasive alternative to conventional DSA in the assessment of PAD patients. J. Magn. Reson. Imaging 2010;32:935–942. © 2010 Wiley‐Liss, Inc.
Increase in blood–brain barrier permeability, oxidative stress, and activated microglia in a rat model of blast‐induced traumatic brain injury
Authors: Readnower Ryan D. , Chavko Mikulas , Adeeb Saleena , Conroy Michael D. , Pauly James R. , McCarron Richard M. , Sullivan Patrick G.
Published: September 2010

Traumatic brain injury (TBI) as a consequence of exposure to blast is increasingly prevalent in military populations, with the underlying pathophysiological mechanisms mostly unknown. In the present study, we utilized an air‐driven shock tube to investigate the effects of blast exposure (120 kPa) on rat brains. Immediately following exposure to blast, neurological function was reduced. BBB permeability was measured using IgG antibody and evaluating its immunoreactivity in the brain. At 3 and 24 hr postexposure, there was a transient significant increase in IgG staining in the cortex. At 3 days postexposure, IgG immunoreactivity returned to control levels. Quantitative immunostaining was employed to determine the temporal course of brain oxidative stress following exposure to blast. Levels of 4‐hydroxynonenal (4‐HNE) and 3‐nitrotyrosine (3‐NT) were significantly increased at 3 hr postexposure and returned to control levels at 24 hr postexposure. The response of microglia to blast exposure was determined by autoradiographic localization of 3H‐PK11195 binding. At 5 days postexposure, increased binding was observed in the contralateral and ipsilateral dentate gyrus. These regions also displayed increased binding at 10 days postexposure; in addition to these regions there was increased binding in the contralateral ventral hippocampus and substantia nigra at this time point. By using antibodies against CD11b/c, microglia morphology characteristic of activated microglia was observed in the hippocampus and substantia nigra of animals exposed to blast. These results indicate that BBB breakdown, oxidative stress, and microglia activation likely play a role in the neuropathology associated with TBI as a result of blast exposure. © 2010 Wiley‐Liss, Inc.
Effects of intermittent hydrostatic pressure and BMP‐2 on osteoarthritic human chondrocyte metabolism in vitro
Authors: Smith R.L. , Lindsey D.P. , Dhulipala L. , Harris A.H.S. , Goodman S.B. , Maloney W.J.
Published: September 2010

Purpose

This study examined effects of intermittent hydrostatic pressure (IHP) and a chondrogenic growth factor, bone morphogenetic protein‐2 (BMP‐2), on anabolic, catabolic, and other metabolic markers in human osteoarthritic (OA) chondrocytes in vitro.

Methods

Articular chondrocytes, isolated from femoral OA cartilage and maintained in high‐density monolayer culture, were examined for effects of BMP‐2 and IHP on gene expression of matrix‐associated proteins (aggrecan, type II collagen, and SOX9) and catabolic matrix metalloproteinases (MMP‐2 and MMP‐3) and culture medium levels of the metabolic markers MMP‐2, nitric oxide (NO), and glycosaminoglycan (GAG). The results were analyzed using a mixed linear regression model to investigate the effects of load and growth factor concentration.

Results

IHP and BMP‐2 modulated OA chondrocyte metabolism in accordance with growth factor concentration independently, without evidence of synergism or antagonism. Each type of stimulus acted independently on anabolic matrix gene expression. Type II collagen and SOX9 gene expression were stimulated by both IHP and BMP‐2 whereas aggrecan was increased only by BMP‐2. IHP exhibited a trend to decrease MMP‐2 gene expression as a catabolic marker whereas BMP‐2 did not. NO production was increased by addition of BMP‐2 and IHP exhibited a trend for increased levels. GAG production was increased by BMP‐2.

Conclusions

This study confirmed the hypothesis that human OA chondrocytes respond to a specific type of mechanical load, IHP, through enhanced articular cartilage macromolecule gene expression and that IHP, in combination with a chondrogenic growth factor BMP‐2, additively enhanced matrix gene expression without interactive effects. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:361–368, 2011
Ultrasound propagation velocity and broadband attenuation can help evaluate the healing process of an experimental fracture
Authors: Barbieri Giuliano , Barbieri Cláudio Henrique , Mazzer Nilton , Pelá Carlos Alberto
Published: September 2010

Ultrasonometry seems to have a future for the evaluation of fracture healing. Ultrasound propagation velocity (USPV) significantly decreases at the same time that bone diameter decreases as healing takes place, thus approaching normal values. In this investigation, both USPV and broadband ultrasound attenuation (BUA) were measured using a model of a transverse mid‐diaphyseal osteotomy of sheep tibiae. Twenty‐one sheep were operated and divided into three groups of seven, according to the follow‐up period of 30, 60, and 90 days, respectively. The progress of healing of the osteotomy was checked with monthly conventional radiographs. The animals were killed at the end of the period of observation of each group, both operated‐upon and intact tibiae being resected and submitted to the measurement of underwater transverse and direct contact transverse and longitudinal USPV and BUA at the osteotomy site. The intact left tibia of the 21 animals was used for control, being examined on a symmetrical diaphyseal segment. USPV increased while BUA decreased with the progression of healing, with significant differences between the operated and untouched tibiae and between the periods of observation, for most of the comparisons. There was a strong negative correlation between USPV and BUA. Both USPV and BUA directly reflect and can help predict the healing of fractures, but USPV alone can be used as a fundamental parameter. Ultrasonometry may be of use in clinical application to humans provided adequate adaptations can be developed. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:444–451, 2011
Resonance Raman spectroscopy and theoretical study on the photodissociation dynamics of formanilide in S3 state
Authors: Pei Kemei , Li Fanglong , Dong Xiaohui , Zheng Xuming
Published: September 2010

Resonance Raman spectra were obtained for formanilide (FA) in acetonitrile solution with 239.5‐ and 245.9‐nm excitation wavelengths in resonance with the S3 state, and density functional theory (DFT) was used to elucidate the electronic transitions and resonance Raman spectra of FA. The spectra indicate that, in the Franck–Condon region, photodissociation dynamics has a multidimensional character with the motions mainly along the CO stretching υ8, the ring CC stretch υ9, the NH wag and ring CCH in‐plane bend υ11, the NH wag and ring CCH in‐plane bend υ12, ring CC stretch and ring CCH in‐plane bend υ16, the NH wag and ring CCH in‐plane bend υ17, the ring CCH in‐plane bend υ18, and the ring trigonal bend υ24. The excited‐state dynamics of the S3 state is discussed, and the results are compared with those previously reported for benzamide (BA) to examine the N‐ or C‐terminal‐substituted aromatic effect of the peptide bond. Copyright © 2010 John Wiley & Sons, Ltd.
Tris(hydroxymethyl)aminomethane‐functionalized silica particles and their application for hydrophilic interaction chromatography
Authors: Bui Nhat Thi Hong , Verhage Jeroen J. , Irgum Knut
Published: September 2010

A new method is presented for synthesizing a highly hydrophilic silica‐based material for use in hydrophilic interaction chromatography. Porous silica particles used as a starting substrate were modified with 3‐bromopropyl trichlorosilane and grafted with glycidyl methacrylate by controlled (“living”) atom transfer radical polymerization in order to introduce an oxirane‐carrying reactive tentacle layer on the silica surface. The grafted material was thereafter subject to an oxirane ring opening reaction with tris(hydroxy‐methyl)aminomethane in dimethylformamide to yield a polymer‐bound equivalent of the well known and highly hydrophilic “TRIS” buffering substance. Chemical characterization was done by diffuse reflectance FT‐IR, X‐ray photoelectron spectroscopy, elemental analysis, and 1H NMR. Porosity and surface area examination was done with Brunauer–Emmett–Teller. Chromatographic application of the material was evaluated by separations of nucleic bases, small organic acids, and common nucleotides under mixed hydrophilic interaction chromatography and weak anion exchange conditions.
Sol–gel microextraction phases for sample preconcentration in chromatographic analysis
Authors: Segro Scott S. , Tran MinhPhuong , Kesani Sheshanka , Alhendal Abdullah , Turner Erica B. , Abdul Malik
Published: September 2010

Sol–gel technology provides a simple and reliable method for solid‐phase microextraction (SPME) fiber preparation through in situ creation of surface‐bonded organic–inorganic hybrid coatings characterized by enhanced thermal stability and solvent‐resistance properties that are important for the coupling of SPME with GC and HPLC, respectively. The sol–gel coating technology has led to the development of an extensive array of sol–gel sorbent coatings for SPME. In this article, sol–gel microextraction coatings are reviewed, with particular attention on their synthesis, characterization, and applications in conjunction with GC and HPLC analyses. In addition, the development of sol–gel‐coated stir bars, their inherent advantages, and applications are discussed. Next, the development and applications of sol–gel capillary microextraction (CME) in hyphenation with GC and HPLC is extensively reviewed. The newly emerging germania‐ and titania‐based sol–gel microextraction phases look promising, especially in terms of pH and hot solvent stability. Finally, sol–gel monolithic beds for CME are reviewed. Such monolithic beds are in a position to greatly improve the extracting capabilities and enhanced sensitivity in CME.
Impact of polyurea structure on grease properties
Authors: Liu L. , Sun H. W.
Published: September 2010

The thickener structure of polyurea grease has a crucial effect on its properties. Therefore, it is very important to study the relationship between a thickener structure and physical and performance properties. In this study, polyurea greases were synthesised, having a different number of urea groups in per polyurea thickener molecule. Properties such as dropping point, penetration, oil separation, shear stability and four‐ball wear and extreme pressure (EP) were evaluated. The result shows that properties of polyurea grease vary with the number of urea group per polyurea molecule. Based on molecular theory, the mechanisms explaining these effects are briefly discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Estimation of the optimal wavelengths for laser‐induced wound healing
Authors: Ankri Rinat , Lubart Rachel , Taitelbaum Haim
Published: September 2010

Background and objectives

According to earlier in vitro low level laser therapy (LLLT) studies, wavelengths in the red and near infrared range, that are absorbed by cytochrome oxidase, stimulate cell growth and hence wound healing. Wavelengths in the blue region that are absorbed by flavins were found to exert a bactericidal effect that is very important for treating infected wounds. However, as far as therapeutic application of light is concerned, penetration into the tissue must be considered. For this purpose we estimated the penetration depth as a function of the relevant wavelengths, using the formulae of the photon migration model for skin tissue.

Methods

We use the photon diffusion model, which is an analytical model for describing light transfer in biological tissues. We refer to the most common chromophores in human tissue and evaluate their volume fraction and concentration in skin cells. These empirically estimated mean wavelength‐dependent absorption coefficients are then substituted in the theoretical expressions for the optical penetration depth in the tissue. The wavelengths, for which the penetration depth is the highest, are the optimal wavelengths to be used in wound healing treatments.

Results

Our model suggests that the optimal wavelengths for therapeutic treatments are in the red region with a local maximum at 730 nm. As to the blue region, a local maximum at 480 nm was found.

Conclusion

Light at 480 nm should be used for treating infected wounds followed by 730 nm light for enhancing wound closure. Lasers Surg. Med. 42:760–764, 2010 © 2010 Wiley‐Liss, Inc.
119/117/115Sn low‐abundance single‐transition correlation spectroscopy (LASSY): sensitivity‐enhanced homonuclear correlation experiments for Sn NMR
Authors: George Christy , Chandrakumar Narayanan
Published: September 2010

We report the implementation of our novel rare‐spin homonuclear correlation experiment, namely, Low‐Abundance Single‐transition correlation SpectroscopY (LASSY), for 119/117/115Sn NMR at natural abundance. Our pulse sequence results in diagonal suppressed COSY‐style display and outperforms the optimal homonuclear correlation experiment for rare spins, which involves double quantum evolution (INADEQUATE CR). The new experiment maximizes efficiency both in respect of pulse transformations as well as relaxation effects, and gives rise to a simplified two‐dimensional (2D) spectrum with considerably reduced crowding, exhibiting only one transition in each cross peak, instead of four. Performance optimization of LASSY is carried out in light of the relatively ‘large’ line widths typical of Sn NMR in solution state. The superior performance of the sequence is demonstrated on dimeric tetraorganodistannoxane samples. Copyright © 2010 John Wiley & Sons, Ltd.
The effects of spatial sampling choices on MR temperature measurements
Authors: Todd Nick , Vyas Urvi , de Bever Josh , Payne Allison , Parker Dennis L.
Published: September 2010

The purpose of this article is to quantify the effects that spatial sampling parameters have on the accuracy of magnetic resonance temperature measurements during high intensity focused ultrasound treatments. Spatial resolution and position of the sampling grid were considered using experimental and simulated data for two different types of high intensity focused ultrasound heating trajectories (a single point and a 4‐mm circle) with maximum measured temperature and thermal dose volume as the metrics. It is demonstrated that measurement accuracy is related to the curvature of the temperature distribution, where regions with larger spatial second derivatives require higher resolution. The location of the sampling grid relative temperature distribution has a significant effect on the measured values. When imaging at 1.0 × 1.0 × 3.0 mm3 resolution, the measured values for maximum temperature and volume dosed to 240 cumulative equivalent minutes (CEM) or greater varied by 17% and 33%, respectively, for the single‐point heating case, and by 5% and 18%, respectively, for the 4‐mm circle heating case. Accurate measurement of the maximum temperature required imaging at 1.0 × 1.0 × 3.0 mm3 resolution for the single‐point heating case and 2.0 × 2.0 × 5.0 mm3 resolution for the 4‐mm circle heating case. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.