bluuebunny/crossref_metadata_2025 huggingface dataset:
Prenatal sonographic findings in a fetus with splenogonadal fusion limb defect syndrome
Authors: Basbug Mustafa , Akgun Hulya , Ozgun Mahmut Tuncay , Turkyilmaz Cagdas , Batukan Cem , Ozcelik Bulent
Published: February 2009

Splenogonadal fusion limb defect syndrome (SGFLD) is a very rare abnormality. We report on a case with prenatal sonographic findings of a fetus with postnatally diagnosed SGFLD syndrome. This is also the second case of prenatal ultrasonographic diagnosis of gastrointestinal malrotation associated with SGFLD. A 26‐year‐old primigravid woman was referred to our clinic because of nonvisualization of both fetal femoral bones at 20 weeks of gestation. A detailed sonographic examination showed complete bilateral absence of lower limbs, micrognathia, single umbilical artery and a right‐sided stomach. Autopsy confirmed prenatal sonographic findings and additionally showed that the spleen was abnormally connected to the left gonad by a fibrous band. In conclusion, although all limbs and both sides were equally affected in most of the reported cases, SGFLD syndrome should be considered in cases with terminal limb defects of lower limbs. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Traumatic pseudoaneurysm of superficial temporal artery: A case report
Authors: Chen Suzi Su‐Hsin , Prasad Shri Kumar
Published: February 2009

We report a case of a 36‐year‐old male who presented with a pulsatile mass at the left temporal region after a head injury. Duplex sonographic examination confirmed the diagnosis of traumatic pseudoaneurysm of the superficial temporal artery. Imaging showed the pseudoaneurysm was partially thrombosed. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Three‐dimensional sonography in the prenatal diagnosis of aortic arch abnormalities
Authors: Turan Sifa , Turan Ozhan M. , Maisel Peccina , Gaskin Peter , Harman Chris R. , Baschat Ahmet A.
Published: February 2009

Purpose

To assess the added value of 3‐dimensional (3D) echocardiography with spatiotemporal image correlation (STIC) in the diagnosis of aortic arch abnormalities in fetuses with isolated abnormal upper thoracic 3‐vessel view (3VV).

Method

A total of 3,420 women underwent a targeted anatomic survey at 18–22 weeks' gestation in a 1‐year period. An isolated abnormal upper thoracic 3VV detected on 2‐dimensional (2D) imaging was followed up by conventional 2D echocardiography and 3D fetal echocardiography with STIC. Offline reconstruction by a second operator blinded to the suspected diagnosis was performed. Neonatal echocardiography and MRI with 3D reconstruction were performed to verify the prenatal diagnosis.

Result

Of the 3,420 patients referred, 4 had an isolated abnormal 3VV (0.09%). A right‐sided aortic arch (RAA, n = 3) and double aortic arch (DAA, n = 1) were suspected. In all aortic arch abnormalities, 3D fetal echocardiography and STIC correctly identified RAA with aberrant left subclavian artery in 3 cases and DAA in 1 case with a degree of definition that was equal to the confirmatory postnatal echocardiography and 3D MRI.

Conclusion

Although the 2D upper 3VV is a powerful screening tool for isolated aortic arch abnormalities, 3D fetal echocardiography with STIC allows an accurate prenatal characterization of the abnormality to a degree that is typically attainable only by post partum imaging. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Aorto‐pulmonary fistula as a late complication of multiple valve replacement after Streptococcus Bovis endocarditis in a patient with occult colon carcinoma
Authors: Florescu Maria , Benea Diana C. , Cerin Gheorghe , Lanzillo Guido , Diena Marco , Cernigliaro Carmelo , Cinteza Mircea , Vinereanu Dragos
Published: February 2009

We report a case of aorto‐pulmonary fistula following multiple valve surgery in a patient with colon carcinoma who had had recurrent episodes of Streptococcus Bovis endocarditis. Diagnosis was made by transesophageal echocardiography and aortography. Patient underwent emergency percutaneous implantation of an aortic endoprosthesis, but he continued to deteriorate and the fatal outcome could not be changed. This case underscores the importance of examination of gastrointestinal tract in patients with Streptococcus Bovis endocarditis. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Endometriomas in the region of a scar from Cesarean section: Sonographic appearance and clinical presentation vary with the size of the lesion
Authors: Francica Giampiero , Scarano Ferdinando , Scotti Luigi , Angelone Giovanni , Giardiello Cristiano
Published: February 2009

Purpose.

To describe the sonographic (US) appearances of endometriomas developed in the vicinity of a scar from Cesarean section and compare sonographic and clinical characteristics of large (≥3 cm) scar endometriomas (LSEs) with small scar endometriomas (SSEs).

Method.

Twenty‐eight consecutive women (mean age, 31 years; range, 20–42) with 31 scar endometriomas (mean diameter, 2.7 cm; range, 0.7–6 cm) were examined by US, including color Doppler imaging prior to surgery. Clinical and US findings in women with LSE were compared with those of women with SSE.

Results.

Twelve patients had 12 LSEs with a mean longest diameter of 4.1 cm (range, 3–6 cm); in 1 case, a large nodule was associated with a small lesion. Sixteen women had 18 SSEs with a mean lesion size of 1.8 cm (range, 0.7–2.6 cm).

The mean time interval between the last Cesarean section and hospital admission was longer in patients with LSE (66 versus 40 months; p < 0.01) as was the mean duration of symptoms before admission (43 versus 17 months; p < 0.01); in addition, 41.6% of patients with LSE had undergone previous inconclusive diagnostic examinations (CT, MRI, fine needle aspiration, or laparoscopy) compared with 0% in patients with SSE (p < 0.05). LSEs more frequently showed cystic portions and fistulous tracts (p < 0.05), loss of round/oval shape (p < 0.05), and increased vascularity (p < 0.05) than SSEs did.

Conclusion.

LSEs were associated with a delay in diagnosis and some US findings that could result in further diagnostic difficulties. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009.
Sonography of the shoulder in hemiplegic patients undergoing rehabilitation after a recent stroke
Authors: Pong Ya‐Ping , Wang Lin‐Yi , Wang Lin , Leong Chau‐Peng , Huang Yu‐Chi , Chen Yu‐Kuang
Published: February 2009

Purpose.

To examine the hemiplegic shoulders for soft‐tissue injury by musculoskeletal sonography and to determine the relationship between the motor functions of the upper extremity and these injuries, which play an important role in hemiplegic shoulder pain and may impede rehabilitation.

Methods.

The following characteristics of 34 acute stroke patients were recorded: age, gender, height, body weight, side of hemiplegia, type and duration of stroke, Brunnstrom stage, subluxation, and degree of spasticity of the upper extremity. On the basis of the Brunnstrom stage, the patients were divided into 2 groups. Patients with stages I, II, or III were categorized under the lower Brunnstrom stage (LBS) group (n = 21), and those with stages IV, V, or VI were allocated to the higher Brunnstrom stage (HBS) group (n = 13). Both shoulders of each patient were examined by musculoskeletal sonography with a 5–10‐MHz linear transducer on 2 separate occasions (i.e., at admission and 2 weeks after rehabilitation).

Results.

With the exception of age, there were no significant differences in the demographic and clinical characteristics of the patients in the 2 groups. Shoulder musculoskeletal sonography revealed soft‐tissue injury in 7 patients (33%) and 15 patients (71%) in the LBS group at admission and 2 weeks after rehabilitation, respectively (p < 0.05), and in 4 patients (31%) in the HBS group both at admission and 2 weeks after rehabilitation.

Conclusions.

Acute stroke patients with poor upper limb motor functions are more prone to soft‐tissue injury of the shoulder during rehabilitation. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009.
Inteins and introns within the prp8 ‐gene of four Eupenicillium species
Authors: Elleuche Skander , Pelikan Constantin , Nolting Nicole , Pöggeler Stefanie
Published: February 2009

Inteins are protein‐intervening sequences that are translated with the host protein and can self‐excise themselves post‐translationally in an autocatalytic process. The flanking regions – called exteins – are then re‐ligated with a new peptide bond, resulting in a mature host protein. Previously, we have identified inteins in the highly conserved 3.2 region of the PRP8 protein from species of the genus Penicillium. These inteins are integrated at the same position as that which has recently been described in PRP8 proteins from different strains of Cryptococcus neoformans and several ascomycetes. In this study, we investigated the presence of PRP8 inteins in four members of the genus Eupenicillium. Two species of this genus, Eupenicillium crustaceum and Eupenicillium baarnense, contain an intein at the same insertion site. Both inteins are mini‐inteins and undergo self‐splicing when heterologously expressed with a model host protein in Escherichia coli. Interestingly, we identified introns in the prp8‐ sequence encoding the 3.2 regions of the PRP8 protein in Eupenicillium meridianum and Eupenicillium terrenum. The introns are located 13 bps and 15 bps downstream of the putative intein insertion site. Here, we consider that the lack of inteins in these two species might be due to the prevention of endonuclease‐mediated intein propagation in the intron‐containing prp8 ‐sequences. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In silico analysis of nickel containing superoxide dismutase evolution and regulation
Authors: Schmidt Astrid , Gube Matthias , Schmidt André , Kothe Erika
Published: February 2009

Superoxide dismutases are essential enzymes involved in detoxification of reactive oxygen by dismutation of the superoxide radical anion. A class of nickel containing superoxide dismutases has been described for streptomycetes and cyanobacteria. In silico analysis was used to study the distribution of genes coding for NiSOD in other taxa and to elucidate signals linked to nickel incorporation and maturation of NiSOD. Data mining revealed homologous proteins from actinobacteria, proteobacteria, chlamydiae, and eukarya (green algae) thus allowing a comparison of protein structural elements. Nickel ligands and maturation signals for N‐terminal proteolysis were highly conserved. Genomic sequences surrounding genes encoding NiSOD homologs were compared in order to detect putative accessory enzymes involved in maturation. An endopeptidase gene linked to sodN coding for NiSOD was found in actinobacteria and cyanobacteria, but not in other taxa. The distribution of NiSOD encoding sequences showed four clusters which are not consistent with the phylogeny of the species. In addition, the different genomic context argues for heterologous gene transfer, most likely from actinobacteria to other taxa. In order to address regulation by nickel availability and incorporation into the mature protein, we present first evidence for putative regulatory nucleotide sequences which will be useful in future studies on nickel uptake and incorporation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The cell wall in heterocyst formation by Anabaena sp. PCC 7120
Authors: Nicolaisen Kerstin , Hahn Alexander , Schleiff Enrico
Published: February 2009

Filamentous cyanobacteria like Anabaena sp. PCC 7120 are able to develop a specialized cell type named heterocyst from vegetative cells in times of nitrogen starvation. Heterocyst development is controlled by the function of two master‐regulators, NtcA and HetR. This review focuses on the remodeling of the cell wall during transition from the vegetative cell to a heterocyst, including the formation of the heterocyst‐specific glycolipid layer and the heterocyst envelope polysaccharide layer. The functional assignment of genes involved therein, their genomic organization and their regulation are highlighted. Communication pathways and exchange routes for metabolites between heterocysts and vegetative cells are discussed. Further on, an overview of the heterocyst outer membrane proteome is given, together with possible functions of the identified proteins in the metabolism of heterocysts. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PTK‐pathways and TGF‐β signaling pathways in schistosomes
Authors: Ting‐An Wang , Hong‐Xiang Zhuge
Published: February 2009

Schistosome parasites have co‐evolved an intricate relationship with their human and snail hosts as well as a novel interplay between the adult male and female parasites. Drug‐induced suppression of female schistosome sexual maturation is an auspicious strategy to combat schistosomiasis since the eggs are the causative agent. Studies on signaling in schistosomes opens a new era for investigation of host–parasite and male–female interactions. We review the role of the TGF‐β signaling pathway in parasite development, host–parasite interactions and male–female interactions. This review also summarizes recent studies suggesting tyrosine kinases as important factors for the regulation of female gonad development. In this context, cytoplasmatic tyrosine kinases of the Src class seem to play especially dominant roles. Moreover, experimental data and theoretical concepts are provided supporting a crosstalk between tyrosine kinase and TGF‐β signaling in the production of vitellocytes. Finally, we take advantage of the schistosome genome project to propose a model for the regulation of vitelline‐cell production and differentiation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon‐concentrating mechanism in a green alga, Chlamydomonas reinhardtii, revealed by transcriptome analyses
Authors: Yamano Takashi , Fukuzawa Hideya
Published: February 2009

Aquatic photosynthetic organisms can acclimate to the variable and limiting availability of CO2 by operation of carbon‐concentrating mechanism (CCM) that allows them to optimize carbon acquisition for photosynthesis. The CCMs of both eukaryotic alga and cyanobacteria function to facilitate CO2 assimilation, when inorganic carbon (Ci; CO2 and/or HCO3–) is limited. By active Ci uptake systems, internal Ci levels are increased and then carbonic anhydrase supplies sufficient CO2 to ribulose 1,5‐bisphosphate carboxylase/oxygenase by the dehydration of accumulated bicarbonate. Although the molecular components of CCM have been intensively studied in cyanobacteria, significant advances in understanding of the eukaryotic CCM have been achieved especially in a model green alga, Chlamydomonas reinhardtii. Recent accumulation of genomic sequence data of algae leads to start comparative genomic analyses of functional components of eukaryotic CCM. This review focuses on the recent advances in identifying and characterizing the components of the CCM by transcriptome analyses of the Chlamydomonas cells that are transferred to CO2‐limiting stress conditions in light. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of nitrogen‐application rate on the biomass, concentration, and composition of essential oils in the leaves and roots of three types of parsley
Authors: Petropoulos Spiros A. , Daferera Dimitra , Polissiou Moschos G. , Passam Harold C.
Published: February 2009

The effect of four levels of nitrogen (N) application (3.2, 16.2, 32.4, and 48.6 g m–2) on the biomass and concentration and composition of essential oils of three parsley types (plain leaf, turnip‐rooted, curl leaf) was investigated in order to determine the optimum N level for oil production by this crop. The concentration of essential oils in the roots and leaves of plain leaf parsley and turnip‐rooted parsley was not affected by N application, but decreased with increasing N rate in curl leaf parsley. However, because the mean foliage biomass for all three types was about 2.5 times higher at 16.2 g m–2 N than in the low‐N‐rate treatment, the mean foliar oil yield increased from 0.68 to 1.38 g m–2. Root biomass increased by a factor of 1.7 at 16.2 g m–2 N (compared to the low‐N‐rate treatment), but oil yield increased only marginally from 0.3 to 0.4 g m–2. The composition of the essential oils of roots and leaves differed between parsley types. Increasing N application caused a reduction in the percentage of β‐phellandrene in the essential oils of parsley leaves. In turnip‐rooted parsley, increasing N caused a reduction in the percentage of myristicin and apiole. Because these three components of the essential oils contribute to parsley aroma, it may be concluded that although application of N fertilizer leads to higher parsley biomass and oil yield per plant, the essential oil components may change and aroma quality may be affected negatively.
Vibrational spectroscopic investigation of the hydrates of manganese(II) oxalate
Authors: Mancilla Nancy , Caliva Valeria , D'Antonio Maria C. , González‐Baró Ana C. , Baran Enrique J.
Published: February 2009

The three known hydrates of manganese(II) oxalate, α‐MnC2O4 · 2H2O, γ‐MnC2O4 · 2H2O and MnC2O4 · 3H2O were synthesized by known procedures and characterized by X‐ray powder diffractometry. Their infrared (IR) and Raman spectra were recorded and discussed on the basis of its structural peculiarities allowing to establish some interesting relations between them and with other, previously investigated, oxalate complexes. The IR spectra of partially deuterated samples of α‐MnC2O4 · 2H2O were also discussed, reinforcing some of the performed assignments. Copyright © 2009 John Wiley & Sons, Ltd.
Some forensic applications of a combined micro‐Raman and scanning electron microscopy system
Authors: Otieno‐Alego Vincent
Published: February 2009

The structural chemical analyser (SCA) is a novel accessory that allows the analytical advantages of Raman spectroscopy and scanning electron microscopy with energy dispersive x‐ray detection (SEM/EDX) to be realised in a single hybridised instrument. The combined Raman–SEM/EDX system permits in situ characterisation of a sample based on both its molecular and elemental makeup. This article demonstrates the potential of using the SCA for interrogating trace evidence for criminalistic purposes. Illustrative evidentiary examples (taken from our laboratory's archives) include the examination of a white paint fragment consisting of several layers of the same colour and a sample of explosive mixture recovered from a place of interest. The sensitive SEM imaging contrast mechanisms enabled the optically identical multiple layers of the white paint to be distinguished easily. The individual layers were then unambiguously analysed to establish their elemental profile (from energy dispersive x‐ray (EDX)) and this was cross‐referenced with the chemical information derived from in situ Raman measurements. X‐ray mapping was used as a fast and convenient way of characterising simultaneously multiple solids constituting the explosive mixture. Typical particles were targeted and analysed both by EDX and Raman spectroscopy revealing an unusual chlorate‐based energetic mixture that also contained 2, 4, 6‐trinitrotoluene (TNT) and 2, 4, 6‐trinitrophenylmethylnitramine (Tetryl). Copyright © 2009 John Wiley & Sons, Ltd.
Ultrafast vibrational dynamics in higher electronic excited states of iodine
Authors: Liebers Jörg , Scaria Abraham , Materny Arnulf , Kleinekathöfer Ulrich
Published: February 2009

By using a combination of an initial pump pulse and a degenerate four‐wave mixing (DFWM) process, we show that an interrogation of the vibrational dynamics occurring in high‐lying electronic states of molecules is possible. As a test case, the technique is applied to iodine in experiment and in simulation. The initial pump pulse is used to populate the B state of molecular iodine in the gas phase. By using an internal time delay in the subsequent DFWM process, which is resonant with the transition between the B state and a higher lying ion‐pair state, the vibrational dynamics of the B ($^{3}\Pi_{\rm {u}}^+$) state as well as of the ion‐pair state could be observed. From the possible ion‐pair states, the states of even symmetry are investigated, which are accessible by a one‐photon transition from the B state. By a proper choice of the wavelengths used for the pump and DFWM beams, the dynamics of ion‐pair states belonging to two different tiers are monitored. Very good agreement between experimental and theoretical results is observed in most of the studied wavelength combinations. Copyright © 2009 John Wiley & Sons, Ltd.
OH‐thermometry using laser polarization spectroscopy and laser‐induced fluorescence spectroscopy in the OH A‐X (1,0) band
Authors: Kiefer J. , Meyerhoefer A. , Seeger T. , Leipertz A. , Li Z. S. , Aldén M.
Published: February 2009

Laser‐induced fluorescence (LIF) and polarization spectroscopy (PS) is used for OH‐thermometry utilizing the off‐diagonal A‐X (1,0) band. Both techniques are used simultaneously in order to allow a comparison of the results. For deriving temperature information from the spectra, three methods are employed: (1) a contour fit method comparing experimental and calculated spectra, (2) spectral fitting of a single highly resolved spectral line and (3) a two‐line intensity ratio approach. In general, both spectroscopic techniques gave similar results. The high‐resolution approach (2) did not deliver reasonable results in our experiments. The most accurate but also most time consuming method was the contour fit (1). For future two‐dimensional temperature measurements, the 2‐line‐method (3) was identified to be the method of choice. The present study contains, to the best of our knowledge, the first polarization spectroscopic study in the A‐X (1,0) band of OH. Copyright © 2009 John Wiley & Sons, Ltd.
Recent developments in operational flood forecasting in England, Wales and Scotland
Authors: Werner Micha , Cranston Michael , Harrison Tim , Whitfield Doug , Schellekens Jaap
Published: February 2009

This paper discusses developments in the last five to six years in the provision of operational flood forecasting in England, Wales, and Scotland. Before the formation of the Environment Agency (EA) in England and Wales and the Scottish Environment Protection Agency (SEPA), flood forecasting capabilities were fragmented. Just over a decade ago both organisations received governmental mandates for the provision of flood forecasting and warning nationally, and have as a result in recent years established systems providing national coverage: the National Flood Forecasting System, and Flood Early Warning System (FEWS) Scotland. These have facilitated a rapid expansion of catchments for which forecasts are provided, and the common framework used has enabled a more rapid introduction of scientific advances in forecasting techniques. This paper gives an overview of some of these recent developments, as well as providing an outlook to further developments to be undertaken in the near future. Copyright © 2009 Royal Meteorological Society
Structure elucidation and NMR assignments of two new pyrrolidinyl quinoline alkaloids from chestnut honey
Authors: Beretta Giangiacomo , Vistoli Giulio , Caneva Enrico , Anselmi Cecila , Maffei Facino Roberto
Published: February 2009

The complete 1H, 13C and 15N NMR spectral assignments of two new alkaloids isolated from chestnut honey and structurally related to kynurenic acid have been made using 1‐D and 2‐D NMR techniques, including COSY, HMQC and HMBC experiments. The new compounds have been identified as 3‐(2′‐pyrrolidinyl)‐kynurenic acid and its γ‐lactam derivative. Copyright © 2009 John Wiley & Sons, Ltd.
Direct MRI mapping of neuronal activity evoked by electrical stimulation of the median nerve at the right wrist
Authors: Xue Yiqun , Chen Xiying , Grabowski Thomas , Xiong Jinhu
Published: February 2009

Magnetic source MRI (msMRI) has being developed recently for direct detections of neuronal magnetic fields to map brain activity. However, controversial results have been reported by different research groups. In this study, more evidence was provided to demonstrate that the neuronal current signal could be detected by MRI using a rapid median nerve stimulation paradigm. The experiments were performed on six normal human participants to investigate the temporal specificity of the effect, as well as inter‐ and intrasubject reproducibility. Significant activation of contralateral primary sensory cortex (S1) was detected 80 ms after stimulation onset (corresponding to the P80 evoked potential peak). The 80‐ms latency S1 activation was observed over three independent sessions for one subject and for all six participants. The magnitude of the signal change was 0.2–0.3%. Coinciding with our expectations, no S1 activation was found when MRI data acquisitions were targeted at the N20 and P30 peaks because of mutual cancellation of magnetic fields generated by those peaks. The results demonstrated good reproducibility of S1 activations and indicated that the S1 activations most likely originated from neuronal magnetic field rather than hemodynamic response. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
The effect of hyperpolarized tracer concentration on myocardial uptake and metabolism
Authors: Schroeder Marie A. , Atherton Helen J. , Cochlin Lowri E. , Clarke Kieran , Radda George K. , Tyler Damian J.
Published: February 2009

Hyperpolarized 13C‐labeled substrates directly provide a source of magnetic resonance (MR) signal to observe the substrates' real‐time uptake and enzymatic conversion. The aim of this study was to optimize the concentration of hyperpolarized [1‐13C]pyruvate infused as a metabolic tracer, by observing the mitochondrial conversion of pyruvate to H13CO3− in heart tissue. Hyperpolarized pyruvate was infused into rats at concentrations between 20 mM and 80 mM and the relationships between [1‐13C]lactate, [1‐13C]alanine, and H13CO3− production and the infused pyruvate concentration were investigated. H13CO3− production reached saturation above 40 mM infused pyruvate concentration, indicating that hyperpolarized MR experiments performed at this concentration maximize the H13CO3− signal with minimal alterations to in vivo substrate composition. Additionally, the linear dependence of alanine production on pyruvate concentration confirmed that hyperpolarized MR methods in the heart reveal enzyme activity, rather than cellular uptake. H13CO3− production demonstrated evidence of sigmoidal enzyme kinetics, a reflection of the allosteric nature of the pyruvate dehydrogenase (PDH) enzyme complex. This protocol could be useful to optimize the infused concentration of other hyperpolarized metabolites in different organs, to ensure adequate MR signal with minimum metabolic perturbation. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Monitoring of release of cargo from nanocarriers by MRI/MR spectroscopy (MRS): Significance of T2/T effect of iron particles
Authors: Kato Yoshinori , Artemov Dmitri
Published: February 2009

To monitor the release of cargo molecules from nanocarriers, a novel MRI/MRS technique was developed and tested. This novel approach uses a simultaneous encapsulation of superparamagnetic iron oxide (SPIO) nanoparticles and either a gadolinium (Gd)‐based paramagnetic contrast agent, Gd‐diethylenetriamine pentaacetic acid bismethylamide(GdDTPA‐BMA), for MRI, or an anticancer agent, 5‐fluorouracil (5‐FU), for MRS. These agents have significantly different diffusion properties due to their different molecular sizes. Strong negative signal enhancement due to the T2 effects of SPIO dominates the positive T1 contrast generated by GdDTPA‐BMA when SPIO and GdDTPA‐BMA are in close proximity (intact form). Positive T1 contrast becomes evident upon release of GdDTPA‐BMA from the carrier once the distance between GdDTPA‐BMA and SPIO molecules is beyond the T2 enhancement range. Similarly, intact nanocarriers loaded with 5‐FU and SPIO have a broad 19F resonance line because line‐width is inversely proportional to T*2, while free 5‐FU appears as a narrow resonance line once it is released from the liposomes. This technique allowed monitoring of the release of cargo molecules from liposomes encapsulating both SPIO and either GdDTPA‐BMA or 5‐FU by MRI/MRS in vitro using 2% agarose gel phantoms. Experimental results demonstrate successful demarcation of the released cargo molecules vs. encapsulated molecules. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Evaluation of the dose distribution gradient in the close vicinity of brachytherapy seeds using electron paramagnetic resonance imaging
Authors: Vanea Emilia S. , Levêque Philippe , Abboud Fadi , Bol Anne , Denis Jean Marc , Kolbun Natallia , Vynckier Stefaan , Gallez Bernard
Published: February 2009

Electron paramagnetic resonance (EPR) spectroscopy has been successfully employed to determine radiation dose using alanine. The EPR signal intensity reflects the number of stable free radicals produced, and provides a quantitative measurement of the absorbed dose. The aim of the present study was to explore whether this principle can be extended to provide information on spatial dose distribution using EPR imaging (EPRI). Lithium formate was selected because irradiation induces a single EPR line, a characteristic that is particularly convenient for imaging purposes.125I‐brachytherapy seeds were inserted in tablets made of lithium formate. Images were acquired at 1.1 GHz. Monte Carlo (MC) calculations were used for comparison. The dose gradient can be determined using two‐dimensional (2D) EPR images. Quantitative data correlated with the dose estimated by the MC simulations, although differences were observed. This study provides a first proof‐of‐concept that EPRI can be used to estimate the gradient dose distribution in phantoms after irradiation. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Noise figure limits for circular loop MR coils
Authors: Kumar Ananda , Edelstein William A. , Bottomley Paul A.
Published: February 2009

Circular loops are the most common MR detectors. Loop arrays offer improved signal‐to‐noise ratios (SNRs) and spatial resolution, and enable parallel imaging. As loop size decreases, loop noise increases relative to sample noise, ultimately dominating the SNR. Here, relative noise contributions from the sample and the coil are quantified by a coil noise figure (NF), NFcoil, which adds to the conventional system NF. NFcoil is determined from the ratio of unloaded‐to‐loaded coil quality factors Q. Losses from conductors, capacitors, solder joints, eddy currents in overlapped array coils, and the sample are measured and/or computed from 40 to 400 MHz using analytical and full‐wave numerical electromagnetic analysis. The Qs are measured for round wire and tape loops tuned from 50 to 400 MHz. NFcoil is determined as a function of the radius, frequency, and number of tuning capacitors. The computed and experimental Qs and NFcoils agree within ∼10%. The NFcoil values for 3 cm‐diameter wire coils are 3 dB, 1.9 dB, 0.8 dB, 0.2 dB, and 0.1 dB, at 1T, 1.5T, 3T, 7T, and 9.4T, respectively. Wire and tape perform similarly, but tape coils in arrays have substantial eddy current losses. The ability to characterize and reliably predict component‐ and geometry‐associated coil losses is key to designing SNR‐optimized loop and phased‐array detectors. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Counteracting radio frequency inhomogeneity in the human brain at 7 Tesla using strongly modulating pulses
Authors: Boulant N. , Mangin J.‐F. , Amadon A.
Published: February 2009

We report flip angle and spoiled gradient echo measurements at 7 Tesla on human brains in three‐dimensional imaging, using strongly modulating pulses to counteract the transmitted radiofrequency inhomogeneity problem. Compared with the standard square pulse results, three points of improvement are demonstrated, namely: (i) the removal of the bright center (typical at high fields when using a quadrature head coil), (ii) the substantial gain of signal in the regions of lowB1intensity, and (iii) an increased 35% signal uniformity over the whole brain at the flip angle where maximum contrast between white and gray matter occurs. We also find by means of simulations that standard BIR‐4 adiabatic pulses need several times more energy to reach a similar performance at the same field strength. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Comparison of model‐based arterial input functions for dynamic contrast‐enhanced MRI in tumor bearing rats
Authors: McGrath Deirdre M. , Bradley Daniel P. , Tessier Jean L. , Lacey Tony , Taylor Chris J. , Parker Geoffrey J.M.
Published: February 2009

When using tracer kinetic modeling to analyze dynamic contrast‐enhanced MRI (DCE‐MRI) it is necessary to identify an appropriate arterial input function (AIF). The measured AIF is often poorly sampled in both clinical and preclinical MR systems due to the initial rapid increase in contrast agent concentration and the subsequent large‐scale signal change that occurs in the arteries. However, little work has been carried out to quantify the sensitivity of tracer kinetic modeling parameters to the form of AIF. Using a preclinical experimental data set, we sought to measure the effect of varying model forms of AIF on the extended Kety compartmental model parameters (Ktrans, ve, and vp) through comparison with the results of experimentally acquired high temporal resolution AIFs. The AIF models examined have the potential to be parameterized on lower temporal resolution data to predict the form of the true, higher temporal resolution AIF. The models were also evaluated through application to the population average AIF. It was concluded that, in the instance of low temporal resolution or noisy data, it may be preferable to use a bi‐exponential model applied to the raw data AIF, or when individual measurements are not available a bi‐exponential model of the average AIF. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
About “axial” and “radial” diffusivities
Authors: Wheeler‐Kingshott Claudia A.M. , Cercignani Mara
Published: February 2009

This article presents the potential problems arising from the use of “axial” and “radial” diffusivities, derived from the eigenvalues of the diffusion tensor, and their interpretation in terms of the underlying biophysical properties, such as myelin and axonal density. Simulated and in vivo data are shown. The simulations demonstrate that a change in “radial” diffusivity can cause a fictitious change in “axial” diffusivity and vice versa in voxels characterized by crossing fibers. The in vivo data compare the direction of the principle eigenvector in four different subjects, two healthy and two affected by multiple sclerosis, and show that the angle, α, between the principal eigenvectors of corresponding voxels of registered datasets is greater than 45° in areas of low anisotropy, severe pathology, and partial volume. Also, there are areas of white matter pathology where the “radial” diffusivity is 10% greater than that of the corresponding normal tissue and where the direction of the principal eigenvector is altered by more than 45° compared to the healthy case. This should strongly discourage researchers from interpreting changes of the “axial” and “radial” diffusivities on the basis of the underlying tissue structure, unless accompanied by a thorough investigation of their mathematical and geometrical properties in each dataset studied. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Absolute quantification of cerebral blood flow in neurologically normal volunteers: Dynamic‐susceptibility contrast MRI‐perfusion compared with computed tomography (CT)‐perfusion
Authors: Ziegelitz Doerthe , Starck Göran , Mikkelsen Irene K. , Tullberg Mats , Edsbagge Mikael , Wikkelsö Carsten , Forssell‐Aronson Eva , Holtås Stig , Knutsson Linda
Published: February 2009

To improve the reproducibility of arterial input function (AIF) registration and absolute cerebral blood flow (CBF) quantification in dynamic‐susceptibility MRI‐perfusion (MRP) at 1.5T, we rescaled the AIF by use of a venous output function (VOF). We compared CBF estimates of 20 healthy, elderly volunteers, obtained by computed tomography (CT)‐perfusion (CTP) and MRP on two consecutive days. MRP, calculated without the AIF correction, did not result in any significant correlation with CTP. The rescaled MRP showed fair to moderate correlation with CTP for the central gray matter (GM) and the whole brain. Our results indicate that the method used for correction of partial volume effects (PVEs) improves MRP experiments by reducing AIF‐introduced variance at 1.5T. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Characterization of white matter fiber bundles with T relaxometry and diffusion tensor imaging
Authors: Cherubini Andrea , Péran Patrice , Hagberg Gisela Elisabeth , Varsi Ambra Erika , Luccichenti Giacomo , Caltagirone Carlo , Sabatini Umberto , Spalletta Gianfranco
Published: February 2009

In this study, diffusion tensor imaging (DTI) and T multiecho relaxometry were combined in 30 healthy subjects at 3T, with the aim of characterizing the spatial distribution of relaxation rates in white matter (WM). Region of interest (ROI) analysis was performed in 23 different fiber tracts automatically defined in standard space. Spearman rank analysis was performed on regional values of T, fractional anisotropy (FA), and radial diffusivity (RD). A strong relationship was observed between the location and direction of fiber bundles and relaxation rates, and adjacent fiber bundles with similar orientation showed very different relaxation rates. Moreover, while relaxation rates varied largely between different fiber tracts, variation of the same parameter within the same anatomical fiber bundle across individuals was remarkably limited. The rich variability of relaxation rates in WM and their complex relationship with DTI data suggested that the two techniques might be sensitive to complementary characteristics of myelin structure. This has tremendous potential to allow for a more detailed understanding of brain development and pathology, in particular in the context of age‐related cognitive decline. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Estimating cerebral blood volume with expanded vascular space occupancy slice coverage
Authors: Glielmi Christopher B. , Schuchard Ronald A. , Hu X.P.
Published: February 2009

A model for quantifying cerebral blood volume (CBV) based on the vascular space occupancy (VASO) technique and varying the extent of blood nulling yielding task‐related signal changes with various amounts of blood oxygenation level‐dependent (BOLD) and VASO weightings was previously described. Challenges associated with VASO include limited slice coverage and the confounding inflow of fresh blood. In this work, an approach that extends the previous model to multiple slices and accounts for the inflow effect is described and applied to data from a multiecho sequence simultaneously acquiring VASO, cerebral blood flow (CBF), and BOLD images. This method led to CBV values (7.9 ± 0.3 and 5.6 ± 0.3 ml blood/100 ml brain during activation [CBVACT] and rest [CBVREST], respectively) consistent with previous studies using similar visual stimuli. Furthermore, an increase in effective blood relaxation (0.65 ± 0.01) compared to the published value (0.62) was detected, likely reflecting inflow of fresh blood. Finally, cerebral metabolic rate of oxygen (CMRO2) estimates using a multiple compartment model without assumption of CBVREST led to estimates (18.7 ± 17.0%) that were within published ranges. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Anti‐vibration and vibration isolator performance of poly(styrene‐butadiene‐ styrene)/ester‐type polyurethane thermoplastic elastomers
Authors: Wu Jyh‐Horng , Li Chia‐Hao , Chiu Hsien‐Tang , Shong Zhi‐Jian , Tsai Peir‐An
Published: February 2009

This investigation presents novel thermoplastic elastomers (TPEs) based on poly(styrene‐butadiene‐styrene) (SBS) and ester‐type polyurethane (TPU‐EX) materials were prepared with varying compositions. A series of investigations were conducted on the relationships between mechanical properties, dynamic mechanical properties, anti‐vibration and vibration isolator properties given, and the different compositions. The experimental results show incompatibilities between SBS and TPU‐EX. SBS mechanical properties, dynamic mechanical properties, anti‐vibration and vibration isolator properties are improved with an increase in the amount of TPU‐EX, suggesting that the blending of SBS with TPU‐EX was consistent with the compound rule. Based on the obtained results, the viscoelasticity of SBS materials, their capacity to isolate vibration, and their anti‐vibration performance can be adjusted by controlling the proportion of TPU‐EX. Copyright © 2009 John Wiley & Sons, Ltd.
Mammosphere‐derived gene set predicts outcome in patients with ER‐positive breast cancer
Authors: Kok Marleen , Koornstra Rutger H , Margarido Tania C , Fles Renske , Armstrong Nicola J , Linn Sabine C , Van‘t Veer Laura J , Weigelt Britta
Published: February 2009

Tumourigenic subpopulations with stem cell‐like features have been identified in breast tumours and breast cancer cell lines. The hormone receptor status, molecular characteristics and clinical significance of these cells are still matters of debate. Enrichment for tumourigenic cells without the requirement of surface markers can be achieved by the in vitro mammosphere culture assay. Here we compared the hormone receptor status and genome‐wide gene expression profiles of mammospheres derived from four oestrogen‐receptor (ER) positive breast cancer cell lines with those of the respective parental cells. Immunohistochemistry and gene expression profiling revealed a significant reduction in the expression of progesterone receptor, proliferation and cell cycle regulated genes in mammospheres when compared to parental cell lines. The 200 most differentially expressed genes between mammospheres and parental cell lines were used to generate a ‘mammosphere‐derived’ gene set. Hierarchical clustering of gene expression profiles of two independent cohorts of primary ER‐positive cancers based on the ‘mammosphere‐derived’ gene set revealed that the subgroup of breast cancers with profiles similar to those of mammospheres has a significantly longer overall survival. In conclusion, tumour‐initiating breast cancer cells grown in mammospheres seem to reside in a quiescent state. ER‐positive breast cancers with expression profiles similar to those of mammospheres have a better outcome, providing evidence in support of the concept that outcome of patients with ER‐positive disease is for a large part determined by cell cycle and proliferation activity. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Global proteomic pattern of Tropheryma whipplei: A Whipple's disease bacterium
Authors: Kowalczewska Malgorzata , Villard Claude , Lafitte Daniel , Fenollar Florence , Raoult Didier
Published: February 2009

The proteome of Tropheryma whipplei, the intracellular bacterium responsible for Whipple's disease (WD), was analyzed using two complementary approaches: 2‐DE coupled with MALDI‐TOF and SDS‐PAGE with nanoLC‐MS/MS. This strategy led to the identification of 206 proteins of 808 predicted ORFs, resolving some questions raised by the genomic sequence of this bacterium. We successfully identified antibiotic targets and proteins with predicted N‐terminal signal sequences. Additionally, we identified a family of surface proteins (known as T. whipplei surface proteins (WiSPs)), which are encoded by a unique group of species‐specific genes and serve as both coding regions and DNA repeats that promote genomic recombination. Comparison of the protein expression profiles of the intracellular facultative host‐associated WD bacterium with other host‐associated, intracellular obligate, and environmental bacteria revealed that T. whipplei shares a proteomic expression profile with other host‐associated facultative intracellular bacteria. In summary, this study describes the global protein expression pattern of T. whipplei and reveals some specific features of the T. whipplei proteome.
Exploring membrane and cytoplasm proteomic responses of Alkalimonas amylolytica N10 to different external pHs with combination strategy of de novo peptide sequencing
Authors: Wang Quanhui , Han Huiming , Xue Yanfen , Qian Zhong , Meng Bo , Peng Fuli , Wang Zhuowei , Tong Wei , Zhou Chuanqi , Wang Qian , Guo Yonghao , Li Gang , Liu Siqi , Ma Yanhe
Published: February 2009

Identification of differentially proteomic responses to external pHs would pave an access for understanding of survival mechanisms of bacteria living at extreme pH environment. We cultured Alkalimonas amylolytica N10 (N10), a novel alkaliphilic bacterium found in Lake Chahannor, in media with three different pHs and extracted the correspondent membrane and cytoplasm proteins for proteomic analysis through 2‐DE. The differential 2‐DE spots corresponding to the altered pHs were delivered to MALDI TOF/TOF MS for protein identification. Since the genomic data of strain N10 was unavailable, we encountered a problem at low rate of protein identification with 18.1%. We employed, therefore, a combined strategy of de novo sequencing to analyze MS/MS signals generated from MALDI TOF/TOF MS. A significantly improved rate of protein identification was thus achieved at over than 70.0%. Furthermore, we extensively investigated the expression of these pH‐dependent N10 genes using Western blot and real‐time PCR. The conclusions drawn from immunoblot and mRNA measurements were mostly in agreement with the proteomic observations. We conducted the bioinformatic analysis to all the pH‐dependent N10 proteins and found that some membrane proteins participated in iron transport were differentially expressed as external pH elevated and most of differential proteins with increased or bell‐shape mode of pH‐dependence were involved in bioenergetic process and metabolism of carbohydrates, fatty acid, amino acids, and nucleotides. Our data thus provide a functional profile of the pH‐responsive proteins in alkaliphiles, leading to elucidation of alkaliphilic‐adaptive mechanism.
Phosphoproteomic analysis of ethylene‐regulated protein phosphorylation in etiolated seedlings of Arabidopsis mutant ein2 using two‐dimensional separations coupled with a hybrid quadrupole time‐of‐flight mass spectrometer
Authors: Li Hao , Wong Wai Shing , Zhu Lin , Guo Hong Wei , Ecker Joseph , Li Ning
Published: February 2009

Ethylene regulates a variety of stress responses and developmental adaptation in plants. In the present study, the phosphoproteomics is adopted to investigate the differential protein phosphorylation by ethylene in Arabidopsis ethylene‐insensitive 2 (ein2) mutant. A total of 224 phosphopeptides were identified, of which 64 phosphopeptides were detected three or more times. Ethylene induces a general reduction in phosphorylated proteins in ein2. Totally, three ethylene‐enhanced and three ethylene‐repressible unique phosphopeptides were identified, respectively. Classification of the cellular functions of these phosphoproteins revealed that 55.5% of them are related to signaling and gene expression. Peptide sequence alignment reveals two highly conserved phosphorylation motifs, PRVD/GSx and SPDYxx. Alignment of these phosphopeptides with Arabidopsis proteins reveals five phosphorylation motifs. Both ethylene‐enhanced and ‐repressible phosphopeptides present in these motifs. EIL‐1, ERF110 transcription factors and Hua enhancer 4 (HEN4) are predicted to contain one of the phosphorylation motifs. The phosphorylation of the motif‐containing peptides has been validated by the in vitro kinase assays coupled with MS analysis. The differential regulation of phosphorylation by ethylene is substantiated by Western dot blot analysis. Taken together, these results suggest that ethylene signals may be transduced by a phosphor‐relay from receptors to transcriptional events via both ein2‐dependent and ‐independent pathways.