bluuebunny/crossref_metadata_2025 huggingface dataset:
Cover Picture: Inherently Chiral Molecular Clips: Synthesis, Chiroptical Properties, and Application to Chiral Discrimination (Chem. Eur. J. 9/2007)
Authors: Fukuhara Gaku , Madenci Süreyya , Polkowska Jolanta , Bastkowski Frank , Klärner Frank‐Gerrit , Origane Yumi , Kaneda Masayuki , Mori Tadashi , Wada Takehiko , Inoue Yoshihisa
Published: March 2007

Chiral molecular clips were separated by HPLC, and their CD spectra are shown on the cover. These clips, the pseudoenantiomers anti‐1 and anti‐2, and diastereomer syn‐3, were used for assignment of the absolute configurations of anti‐1 and anti‐2. The space‐filling structures of anti‐1 and anti‐2, also shown, were calculated by conducting a Monte‐Carlo conformer search using the force field MMFF94 implemented in SPARTAN '04. For more details, see the Full Paper by Y. Inoue, F.‐G. Klärner et al. on page 2473 ff.
Eph receptor expression defines midline boundaries for ephrin‐positive migratory neurons in the enteric nervous system of Manduca sexta
Authors: Coate Thomas M. , Swanson Tracy L. , Proctor Thomas M. , Nighorn Alan J. , Copenhaver Philip F.
Published: March 2007

Eph receptor tyrosine kinases and their ephrin ligands participate in the control of neuronal growth and migration in a variety of contexts, but the mechanisms by which they guide neuronal motility are still incompletely understood. By using the enteric nervous system (ENS) of the tobacco hornworm Manduca sexta as a model system, we have explored whether Manduca ephrin (MsEphrin; a GPI‐linked ligand) and its Eph receptor (MsEph) might regulate the migration and outgrowth of enteric neurons. During formation of the Manduca ENS, an identified set of ∼300 neurons (EP cells) populates the enteric plexus of the midgut by migrating along a specific set of muscle bands forming on the gut, but the neurons strictly avoid adjacent interband regions. By determining the mRNA and protein expression patterns for MsEphrin and the MsEph receptor and by examining their endogenous binding patterns within the ENS, we have demonstrated that the ligand and its receptor are distributed in a complementary manner: MsEphrin is expressed exclusively by the migratory EP cells, whereas the MsEph receptor is expressed by midline interband cells that are normally inhibitory to migration. Notably, MsEphrin could be detected on the filopodial processes of the EP cells that extended up to but not across the midline cells expressing the MsEph receptor. These results suggest a model whereby MsEphrin‐dependent signaling regulates the response of migrating neurons to a midline inhibitory boundary, defined by the expression of MsEph receptors in the developing ENS. J. Comp. Neurol. 502:175–191, 2007. © 2007 Wiley‐Liss, Inc.
Deletion of α‐neurexins does not cause a major impairment of axonal pathfinding or synapse formation
Authors: Dudanova Irina , Tabuchi Katsuhiko , Rohlmann Astrid , Südhof Thomas C. , Missler Markus
Published: March 2007

α‐Neurexins are synaptic cell‐surface molecules that are required for Ca2+‐triggered exocytosis. Mice lacking all three α‐neurexins show drastically reduced neurotransmitter release at excitatory and inhibitory synapses and die early postnatally. Although previous histological analysis of newborn α‐neurexin triple mutants revealed only a moderate reduction in the density of type II synapses in the brainstem, cell culture studies proposed that neurexins are prominently involved in synapse formation. To assess the contribution of α‐neurexins to the formation and structural properties of synapses in vivo, we performed a detailed morphological analysis of the brains from surviving adult double knockout mice lacking two of the three α‐neurexins. Despite their impaired neurotransmission, we did not observe any gross anatomical defects or changes in the distribution of synaptic proteins in adult mutants. Only mild structural alterations were found: a ∼20% reduction of neuropil area in many brain regions, resulting predominantly from shortened distal dendritic branches and fewer spines, as demonstrated by Golgi impregnation of pyramidal neurons. Quantitative electron microscopy revealed ultrastructurally normal type I and II terminals and a ∼30% decrease in the density of type II synapses in the neocortex. To exclude errors in pathfinding, we investigated axonal projections in the olfactory bulb of newborn knockouts and did not observe any changes. Therefore, α‐neurexins are not essential for the formation of the vast majority of synapses in vivo but rather regulate the function of these synapses. J. Comp. Neurol. 502:261–274, 2007. © 2007 Wiley‐Liss, Inc.
Cytological organization of the central gelatinosa in the turtle spinal cord
Authors: Trujillo‐Cenóz Omar , Fernández Anabel , Radmilovich Milka , Reali Cecilia , Russo Raúl E.
Published: March 2007

This paper deals with the cytological organization of the central gelatinosa (CG) in the spinal cord of juvenile (2–12 months) turtles. We found two main cell classes in the CG: one with characteristics of immature neurons, the other identified as radial glia (RG). The cells surrounding the central canal formed radial conglomerates in such a way that the RG lamellae covered the immature neurons. We found three major subpopulations of RG that expressed S‐100, glial fibrillary acidic protein, or both proteins. Electron microscopic images showed gap junctions interconnecting RG. As with the mammalian neuroepithelial cells, most CG cells displayed intrinsic polarity expressed by structural and molecular differences between the most apical and basal cell compartments. The apical zone was characterized by the occurrence of a single cilium associated with a conspicuous centrosomal complex. We found a prominent expression of the PCM‐1 centrosomal protein concentrated close to the central canal lumen. In the particular case of RG, the peripheral end feet contacted the subpial basement membrane. We also found “transitional cell forms” difficult to classify by the usual imaging approaches. Functional clues obtained by patch‐clamp recordings of CG cells defined some of them as already committed to follow the neuronal lineage, whereas others had properties of less mature or migrating cells. The CG appeared as a richly innervated region receiving terminal branches from nerve plexuses expressing γ‐aminobutyric acid, serotonin, and glutamate. The results presented here support our previous studies indicating that the CG is an extended neurogenic niche along the spinal cord of turtles. J. Comp. Neurol. 502:291–308, 2007. © 2007 Wiley‐Liss, Inc.
Crystal growth of mixed‐valence ammonium vanadates
Authors: Ren Tie‐Zhen , Yuan Zhong‐Yong , Zou Xiaodong
Published: March 2007

A new method has been developed for the synthesis of mixed‐valence ammonium vanadate crystals. Single crystals of (NH4)2V3O8 were synthesized on a large scale by hydrothermal reduction of NH4VO3 in ethanol‐H2O solutions in the presence of triblock copolymer Pluronic P123. The crystals are shining thin plates with (001) cleavage planes. Calcination of the (NH4)2V3O8 crystals at 300°C or above resulted in pure phases of V2O5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of a layered chlorozincophosphate templated by protonated 4‐methylpiperidine
Authors: Kefi R. , Lefebvre F. , Ben Nasr C.
Published: March 2007

A chlorozincophosphate with the composition Zn(HPO4)Cl·[C6H14N] has been synthesised under mild conditions in water medium in presence of 4‐methylpiperidine as organic template. The structure was determinated by single crystal X‐ray diffraction. The unit cell is orthorhombic (space group Pcab) with a = 8.743(9), b = 9.592(6), c = 26.573(6) Å, Z = 8 and V = 2228.91(12) Å3. The structure involves a network of ZnO3Cl and PO3(OH) tetrahedra forming macroanionic inorganic layers with four and eight‐membered rings. Charge balance is achieved by the protonated amine which is trapped in the interlayers space and interacts with the organic framework through hydrogen bonding. Solid state 31P and 13C MAS‐NMR spectroscopies are in full agreement with the X‐ray structure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation, single crystal growth and characterization of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper
Authors: Wang X. Q. , Xu D. , Ren Q. , Zhang G. H. , Sun X. B. , Hou X. Q. , Guo W. F. , Lü H.
Published: March 2007

The preparation and single crystal growth of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper, (I), are described. The energy gap Eg of (I) is about 2.38 eV. The nonlinear optical susceptibility χ(3) is about 1.3×10‐3 esu at 1064 nm. The characterization of (I) has been performed by electronic absorption, infrared and X‐ray powder diffraction spectroscopy. The thermal behavior of (I) has been investigated by means of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements in air. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal growth and magnetic properties of the copper coordination polymer [Cu(µ ‐C2O4)(4‐aminopyridine)2(H2O)]n
Authors: Prokofiev A. V. , Assmus W. , Remović‐Langer K. , Pashchenko V. , Tsui Y. , Wolf B. , Lang M.
Published: March 2007

In this paper, we consider various ways of crystal growth of the polymer [Cu(µ ‐C2O4)(4‐aminopyridine)2(H2O)]n. Single crystals of the size of 1.5×1.5×0.2 mm3 have been grown by a slow diffusion technique from solutions of the monoammine copper complex and of the mixture of potassium oxalate and aminopyridine with the stoichiometric ratio. Magnetic susceptibility and ESR measurements have been performed on single crystals large enough for investigating anisotropic properties. The susceptibility can be well described within the model of a Heisenberg antiferromagnetic spin chain. The magnetic measurements reveal a small concentration of paramagnetic moments reflecting the high quality of the single crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of 4‐(2‐hydroxyphenylamino)‐pent‐3‐en‐2‐one single crystals
Authors: Parekh B. B. , Purohit D. H. , Sagayaraj P. , Joshi H. S. , Joshi M. J.
Published: March 2007

4‐(2‐hydroxyphenylamino)‐pent‐3‐en‐2‐one (HPAP) was synthesized and single crystals were grown by the solution growth technique using methanol as a solvent. The crystals having orthorhombic symmetry were characterized by single crystal XRD, FTIR spectroscopy, NMR spectroscopy, TGA, DSC and dielectric studies. Very less variation in the value of dielectric constant is found for different frequencies of applied field. The crystals were exhibiting positive photoconductivity and poor NLO responses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cell‐autonomous control of interferon type I expression by indoleamine 2,3‐dioxygenase in regulatory CD19+ dendritic cells
Authors: Manlapat Anna K. , Kahler David J. , Chandler Phillip R. , Munn David H. , Mellor Andrew L.
Published: March 2007

Following CD80/86 (B7) and TLR9 ligation, small subsets of splenic dendritic cells expressing CD19 (CD19+ DC) acquire potent T cell regulatory functions due to induced expression of the intracellular enzyme indoleamine 2,3‐dioxygenase (IDO), which catabolizes tryptophan. In CD19+ DC, IFN type I (IFN‐α) is the obligate inducer of IDO. We now report that IFN‐α production needed to stimulate high‐level expression of IDO following B7 ligation is itself dependent on basal levels of IDO activity. Genetic and pharmacologic ablation of IDO completely abrogated IFN‐α production by CD19+ DC after B7 ligation. In contrast, IDO ablation did not block IFN‐α production by CD19+ DC after TLR9 ligation. IDO‐mediated control of IFN‐α production depended on tryptophan depletion as adding excess tryptophan also blocked IFN‐α expression after B7 ligation. Consistent with this, DC from mice deficient in general control of non‐derepressible‐2 (GCN2)‐kinase, a component of the cellular stress response to amino acid withdrawal, did not produce IFN‐α following B7 ligation, but produced IFN‐α after TLR9 ligation. Thus, B7 and TLR9 ligands stimulate IFN‐α expression in CD19+ DC via distinct signaling pathways. In the case of B7 ligation, IDO activates cell‐autonomous signals essential for IFN‐α production, most likely by activating the GCN2‐kinase‐dependent stress response.

See accompanying commentary: http://dx.doi.org/10.1002/eji.20073737184
Culture conditions affect proliferative responsiveness of olfactory ensheathing glia to neuregulins
Authors: De Mello T. R. , Busfield S. , Dunlop S. A. , Plant G. W.
Published: March 2007

Olfactory ensheathing glia (OEG) have been used to improve outcome after experimental spinal cord injury and are being trialed clinically. Their rapid proliferation in vitro is essential to optimize clinical application, with neuregulins (NRG) being potential mitogens. We examined the effects of NRG‐1β, NRG‐2α, and NRG3 on proliferation of p75‐immunopurified adult OEG. OEG were grown in serum‐containing medium with added bovine pituitary extract and forskolin (added mitogens) or in serum‐containing medium (no added mitogens). Cultures were switched to chemically defined medium (no added mitogens or serum), NRG added and OEG proliferation assayed using BrdU. OEG grown initially with added mitogens were not responsive to added NRGs and pre‐exposure to forskolin and pituitary extract increased basal proliferation rates so that OEG no longer responded to added NRG. However, NRG promoted proliferation but only if cells were initially grown in mitogen‐free medium. Primary OEG express ErbB2, ErbB3, and small levels of ErbB4 receptors; functional blocking indicates that ErbB2 and ErbB3 are the main NRG receptors utilized in the presence of NRG‐1β. The long‐term stimulation of OEG proliferation by initial culture conditions raises the possibility of manipulating OEG before therapeutic transplantation. © 2007 Wiley‐Liss, Inc.
Ferritin—a mediator of apoptosis?
Authors: Bresgen Nikolaus , Ohlenschläger Ingo , Fiedler Brigitte , Wacht Nathalie , Zach Susanne , Dunkelmann Bettina , Arosio Paolo , Kuffner Elisabeth , Lottspeich Friedrich , Eckl Peter M.
Published: March 2007

Previously we have demonstrated an apoptosis inducing activity for a rat hepatocyte conditioned medium (CM) presumably mediated by acidic isoferritins. Here, we present support for this assumption since isoferritins purified from different rat hepatocyte CM significantly enhanced the frequency of apoptotic cells in primary rat hepatocytes, an effect completely inhibited by a neutralizing anti‐H‐ferritin antibody. The apoptosis induction appears to be related to a 43 kDa ferritin subunit contained in the isoferritins released from primary hepatocytes, presumably representing a ferritin heavy/light chain heterodimer. In addition, these isoferritins immunologically crossreact with antibodies raised against placental isoferritin p43‐PLF (which also contains a 43 kDa ferritin subunit) and melanoma‐derived H‐chain ferritin, representing ferritin isoforms which reveal immunomodulatory properties. Furthermore, p53 and FasL are upregulated upon isoferritin treatment in a time dependent mode, and apoptosis induction can be suppressed by neutralizing anti‐FasL antibodies. Proapoptotic Bid is upregulated too and translocated into mitochondria in primary hepatocytes exposed to the isoferritins purified from the CM. Finally, epidermal growth factor (EGF) and dexamethasone (DEX), which counteract proapoptotic mitochondrial signalling, almost completely abolished the proapoptotic effect of the hepatocyte derived isoferritins. In conclusion, our findings demonstrate that acidic isoferritins with homology to immunomodulatory ferritin isoforms (p43‐PLF, melanoma‐derived‐H‐chain ferritin) are released from hepatocytes in vitro, and are able to stimulate upregulation of p53 and mediate apoptosis involving Fas (CD95) signalling as well as addressing the intrinsic mitochondrial proapoptotic pathway. J. Cell. Physiol. 212: 157–164, 2007. © 2007 Wiley‐Liss, Inc.
Human papillomavirus‐16 E7 interacts with siva‐1 and modulates apoptosis in HaCaT human immortalized keratinocytes
Authors: Severino Anna , Abbruzzese Claudia , Manente Lucrezia , Valderas Álvaro Avivar , Mattarocci Stefano , Federico Antonio , Starace Giuseppe , Chersi Alberto , Mileo Anna Maria , Paggi Marco G.
Published: March 2007

The viral factor E7 plays a key role in the well‐established association between “high‐risk” Human Papillomavirus (HPV) infection and the development of epithelial malignant tumors, as uterine cervix and ano‐genital cancer. To delve into the molecular mechanisms of HPV‐mediated cell transformation, we searched for novel potential cellular targets of the HPV‐16 E7 oncoprotein, by means of the yeast two‐hybrid technique, identifying a protein–protein interaction between HPV‐16 E7 and the pro‐apoptotic cellular factor Siva‐1. Using co‐precipitation assays and the “PepSets” technique, we confirmed this physical interaction and mapped accurately, for both proteins, the amino acid residues involved. Additionally, we found that HPV‐16 E7 competed in vitro with the binding of the Bcl‐XL anti‐apoptotic factor to Siva‐1, an interaction that has a major inference in UV radiation‐induced apoptosis. In HaCaT immortalized human keratinocytes, forced HPV‐16 E7 expression by retroviral infection caused Siva‐1 transcript up‐regulation, detected by cDNA macroarray hybridization and real‐time quantitative PCR, paralleled by an increased amount of protein. Confirming the anti‐apoptotic role of HPV‐16 E7 in the HaCaT cellular model, evaluated by nuclear morphology, we also found that Siva‐1 expression produced a significant increase of the apoptotic rate in UV radiation‐exposed HaCaT cells, and that this effect resulted explicitly counteracted by HPV‐16 E7. Being apoptosis a key physiological process for the elimination of irreversibly injured cells, the anti‐apoptotic role of HPV‐16 E7, performed at least by its interference with Siva‐1, can be considered an additional mechanism for the survival of damaged, potentially transforming, cell clones. J. Cell. Physiol. 212: 118–125, 2007. © 2007 Wiley‐Liss, Inc.
Matrix metalloproteinase activity is necessary for thymosin beta 4 promotion of epithelial cell migration
Authors: Qiu Ping , Kurpakus‐Wheater Michelle , Sosne Gabriel
Published: March 2007

Studies from our laboratory provide substantial evidence that thymosin beta 4, (Tβ4), an actin‐sequestering protein, promotes corneal wound healing through its ability to stimulate epithelial cell migration. Matrix metalloproteinases (MMPs), which are expressed in a wide variety of tissues including the cornea, also play a key role in epithelial cell migration and wound healing. In this study we investigated the role of MMPs in Tβ4‐stimulated corneal epithelial cell migration. In Boyden chamber assays, XG076, an inhibitor of the conversion of pro‐ to active MMPs, had no effect on epithelial cell migration stimulated by exogenous activated MMP‐1. However, in in vitro migration assays where the activation of pro‐MMPs was blocked, XG076 significantly inhibited cell migration and wound healing in the presence or absence of Tβ4. GM6001, a broad‐spectrum inhibitor of active MMPs and selective MMP inhibitors, also suppressed Tβ4‐stimulated cell migration. Tβ4 upregulated MMP‐1 gene and protein expression in primary human corneal epithelial cells and in transformed human corneal epithelial cells following scrape wounding. From these results we conclude that MMP catalytic activity is necessary for Tβ4 promotion of epithelial cell migration. These novel findings are the first to demonstrate a functional link between the two. J. Cell. Physiol. 212: 165–173, 2007. © 2007 Wiley‐Liss, Inc.
Measurement of liver fat content using selective saturation at 3.0 T
Authors: Cotler Scott J. , Guzman Grace , Layden‐Almer Jennifer , Mazzone Theodore , Layden Thomas J. , Zhou Xiaohong Joe
Published: March 2007

Purpose

To validate an MRI technique for measuring liver fat content by calibrating MRI readings with liver phantoms and comparing MRI measurements in human subjects with estimates of liver fat content on liver biopsy specimens.

Materials and Methods

The MRI protocol consisted of fat and water imaging by selective saturation using a 3.0‐T scanner. A water phantom and liver phantoms were scanned before each of 10 human subjects who underwent a liver biopsy to assess for nonalcoholic fatty liver disease (NAFLD). Liver fat content in human subjects was derived from a calibration curve generated by scanning the phantoms. Liver fat was also estimated by optical image analysis and pathologists' assessment of histologic sections.

Results

MRI measurements of the liver phantoms were highly reproducible. Measurements of liver fat content in human subjects made by MRI in two areas of the liver were strongly correlated (r = 0.98, P < 0.001). MRI measurements were highly associated with estimates of liver fat content made by optical image analysis (r = 0.96, P < 0.001) and with estimates made by the pathologists (r = 0.93, P < 0.001).

Conclusion

We validated a technique for quantifying liver fat content based on selective fat and water imaging. The technique is accurate and reproducible and provides a noninvasive method to obtain serial measurements of liver fat content in human subjects. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Molecular imaging and therapy of atherosclerosis with targeted nanoparticles
Authors: Wickline Samuel A. , Neubauer Anne M. , Winter Patrick M. , Caruthers Shelton D. , Lanza Gregory M.
Published: March 2007

Advances in bionanotechnology are poised to impact the field of cardiovascular diagnosis and therapy for decades to come. This review seeks to illustrate selected examples of newly developed diagnostic and therapeutic nanosystems that have been evaluated in experimental atherosclerosis, thrombosis, and vascular biology. We review a variety of nanotechnologies that are capable of detecting early cardiovascular pathology, as well as associated imaging approaches and conjunctive strategies for site‐targeted treatment with nanoparticle delivery systems. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Four‐dimensional single breathhold magnetic resonance imaging using kt‐BLAST enables reliable assessment of left‐ and right‐ventricular volumes and mass
Authors: Jahnke Cosima , Nagel Eike , Gebker Rolf , Bornstedt Axel , Schnackenburg Bernhard , Kozerke Sebastian , Fleck Eckart , Paetsch Ingo
Published: March 2007

Purpose

To prospectively determine the accuracy of four‐dimensional (4D) kt‐broad‐use linear acquisition speed‐up technique (BLAST) accelerated MRI (kt‐BLAST) for the assessment of left‐ventricular (LV) volumes and mass as well as right‐ventricular (RV) volumes in comparison to standard multiple breathhold cine imaging.

Materials and Methods

A total of 40 patients with suspected or known coronary artery disease (CAD) underwent cardiac MRI. In each patient a standard multislice cine steady‐state free precession (SSFP) sequence was performed with complete ventricular coverage during multiple breathholds. Additionally, a kt‐BLAST‐accelerated 4D sequence with complete ventricular coverage was acquired during one single breathhold. For comparison of SSFP and kt‐BLAST, the following LV parameters were determined: end‐diastolic and end‐systolic volumes, ejection fraction, end‐diastolic diameter and mass. For comparison of RV dimensions, end‐diastolic and end‐systolic volumes and ejection fraction were assessed.

Results

LV volumes, ejection fraction, diameter, and mass showed a strong correlation between SSFP and kt‐BLAST (r = 0.98–0.99; P < 0.01). In addition, RV parameters demonstrated a high correlation (r = 0.97–0.98; P < 0.01). For all parameters, the calculated bias between both methods was found to be minimal (0.4–4%).

Conclusion

4D kt‐BLAST‐accelerated MRI enabled the accurate assessment of LV and RV quantitative parameters during one single breathhold when compared to standard multislice, multiple breathhold SSFP imaging. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Assessment of human brain motion using CSPAMM
Authors: Soellinger Michaela , Ryf Salome , Boesiger Peter , Kozerke Sebastian
Published: March 2007

Purpose

To quantify periodic displacement in the cranium using complementary spatial modulation of magnetization (CSPAMM) with harmonic phase (HARP) postprocessing.

Materials and Methods

CSPAMM tagging sequence with separate tag‐line preparation in two orthogonal directions was applied on 10 healthy volunteers in combination with HARP for tissue displacement mapping.

Results

Important features of brain dynamics, such as caudal displacement amplitude and the time‐to‐peak of the pulse wave were derived for six regions in the brain. Peak displacement values amounted to 0.18 ± 0.02 mm, 0.10 ± 0.01 mm, 0.09 ± 0.02 mm, and 0.04 ± 0.01 mm for regions in the pons, cerebellum, corpus callosum (splenium), and frontal lobe, respectively. Displacement values of the pons differed significantly from all other regions measured. With the additional information of the time‐to‐peak measure all six regions except the corpus callosum (splenium) and cerebellum can be distinguished. The values found suggest that the pulse wave travels from the brain stem first occipitally and then to the frontal lobe, where peak values appear later and are significantly attenuated.

Conclusion

Direct quantification of periodic caudal brain tissue displacement is feasible with the proposed method, and several brain regions can be distinguished through peak displacement and time‐to‐peak values. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Krylov model order reduction of finite element approximations of electromagnetic devices with frequency‐dependent material properties
Authors: Wu Hong , Cangellaris Andreas C.
Published: March 2007

A methodology is presented for the Krylov subspace‐based model order reduction of finite element models of electromagnetic structures with material properties and impedance boundary conditions exhibiting arbitrary frequency dependence. The proposed methodology is a generalization of an equation‐preserving Krylov model order reduction scheme for methodology for second‐order, linear dynamical systems. The emphasis of this paper is on the application of this method to the broadband model order reduction of planar circuits including lossy strips of arbitrary thickness and lossy reference planes. In particular, it is shown that the proposed model order reduction methodology provides for the accurately modelling of the impact of the frequency dependence of the internal impedance per unit length of the thick lossy strip on the electromagnetic response of the stripline structure over a very broad, multi‐GHz frequency band, extending all the way down to frequencies in the DC neighbourhood. In addition, the application of the proposed methodology to the broadband modelling of electromagnetic coupling between strips on either side of a lossy ground plane is demonstrated. Copyright © 2007 John Wiley & Sons, Ltd.
Interplay of leukemia inhibitory factor and retinoic acid on neural differentiation of mouse embryonic stem cells
Authors: Martín‐Ibáñez Raquel , Urbán Noelia , Sergent‐Tanguy Solène , Pineda José Ramón , Garrido‐Clua Núria , Alberch Jordi , Canals Josep M.
Published: March 2007

Embryonic stem (ES) cells have great potential for cell replacement in neurodegenerative disorders. Implantation of these cells into the brain, however, requires their prior differentiation. We examined the interplay between leukemia inhibitory factor (LIF) and retinoic acid (RA) on neural differentiation of mouse ES (mES) cells. Mouse embryonic stem cells were allowed to form cell aggregates, the so‐called embryoid bodies (EBs), in the absence or presence of LIF. In the absence of LIF, mES cells downregulated the expression of the undifferentiated mES cell marker Oct‐3/4, and increased mRNA levels of two neural precursor markers, Sox‐1 and Nestin, as well as the neuronal marker β‐tubulin III. This neuronal differentiation was enhanced by treating EBs with RA. Moreover, RA irreversibly increased the number of postmitotic neurons in culture, as shown by the reduction of proliferating mES cells and the increase in β‐tubulin III‐positive cells 6 days after RA removal, which in turn affected mES cell viability. The addition of LIF during EBs formation, however, blocked completely this neuronal differentiation. Our findings also showed that pre‐differentiation of mES cells in vitro avoided the teratocarcinoma formation observed when proliferating mES cells were grafted into the brain. In addition, mES cells pre‐differentiated with RA in culture showed a reduction in proliferation and the presence of neural phenotypes after grafting. In conclusion, the present results indicate that RA enhances neuronal differentiation of mES cells in the absence of LIF, although it compromises cell viability and transplantation. © 2007 Wiley‐Liss, Inc.
NO‐induced downregulation of HSP10 and HSP60 expression in the postischemic brain
Authors: Kim Seung‐Woo , Lee Ja‐Kyeong
Published: March 2007

Heat shock protein 60 (HSP60) and HSP10 are mitochondrial chaperonin proteins and are responsible for the folding of newly imported proteins and 13 polypeptides encoded by mitochondrial DNA. The expressions of HSP60 and HSP10 are regulated simultaneously because these genes are localized head to head on chromosome, separated by a bidirectional promoter, which harbors heat shock element (HSE), CHOP, STAT3, and SP1 binding sites. In the present study, we show that the expressions of HSP60 and HSP10 in the brain after middle cerebral artery occlusion (MCAO) are induced significantly. Interestingly, the expressions of HSP60 and HSP10 were further upregulated by the administration of aminoguanidine (AG), an inhibitor of the inducible nitric oxide synthase (iNOS), which is known to reduce ischemic damage in an animal model after MCAO. The results obtained in the present study suggest that HSP10 and HSP60 are induced in the postischemic brain, yet are downregulated by NO generated from 12 hr after MCAO/reperfusion. The downregulation of HSP60 and HSP10 by NO were confirmed in vitro, wherein HSP10 and SHP60 expressions were increased by treatment of LPS and IFNγ (LPS/INFγ) in C6 astroglioma cells and further upregulated by NMMA, another iNOS inhibitor. Reporter gene analysis combined with deletion and mutation studies showed that STAT3 binding site in the bidirectional promoter is responsible for LPS/INFγ‐induced upregulation and for downregulation by NO. Our results indicated that NO suppresses HSP60 and HSP10 inductions in the postischemic brain by suppressing STAT3 binding to its recognition site. © 2007 Wiley‐Liss, Inc.
Estimation of the mechanical property of meniscus using ultrasound: Examinations of native meniscus and effects of enzymatic digestion
Authors: Yasura Ko , Mizuno Yasuyuki , Nakagawa Yasuaki , Mori Koji , Takenaka Makoto , Ohashi Tetsuo , Yamada Keisuke , Kobayashi Masahiko , Ando Keiji , Kuroki Hiroshi , Suzuki Takashi , Ikeuchi Ken , Tsutsumi Sadami , Nakamura Takashi
Published: March 2007

We previously developed a novel ultrasound assessment system featuring wavelet transform to evaluate the material properties of articular cartilage. We aimed in this study to demonstrate the feasibility of quantitative evaluation of meniscus using ultrasound and to elucidate the relationships between its acoustic, mechanical, and biochemical properties. Meniscal disc specimens from mature pigs were assessed by ultrasound and compression testing, and their correlation was analyzed. A positive correlation was found between the ultrasound signal intensity and apparent Young's modulus (r = 0.61). Subsequently, the porcine meniscal discs were treated with various enzymes and then characterized by ultrasound, by compression tests, by biochemical analyses, and by histology and immunohistochemistry. The signal intensity was decreased not by hyaluronidase but by collagenase treatment. Hyaluronidase‐treated menisci showed a discrepancy between acoustic and mechanical properties, suggesting that the ultrasound reflection could not detect a reduction in proteoglycan content. Also, ultrasound signal intensity could only reflect superficial layers of the material. Several limitations exist at present, and further studies and improvements of the device are required. However, given the noninvasive nature and the requirement of only small equipment, this ultrasound assessment system will be an instrumental diagnostic tool for meniscal function in both research and clinical fields. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:884–893, 2007
Cartilaginous deposits in subchondral bone in regions of exposed bone in osteoarthritis of the human knee: Histomorphometric study of PRG4 distribution in osteoarthritic cartilage
Authors: Zhang Dong , Johnson Lanny J. , Hsu Hu‐Ping , Spector Myron
Published: March 2007

The objective of this study was to identify and characterize cartilaginous deposits aggregates in the subchondral bone in areas of the human osteoarthritic knee with exposed bone. A specific aim was to determine the distribution of the joint lubrication molecule, lubricin/superficial zone protein [referred to by its gene, proteoglycan4 (PRG4)], in these cartilaginous deposits and in osteoarthritic cartilage. This work was carried out in the context of assessing the potential contribution of these chondrocyte aggregates for joint resurfacing in certain cartilage repair procedures. The discarded bone cuts of femoral condyles and tibial plateaus were collected from 11 patients with advanced osteoarthritis (OA) of the knee during total knee arthroplasty; 9 women and 2 men with a mean age of 68 years. Sections of paraffin‐embedded tissue were stained with Safranin‐O, and with antibodies to type II collagen, α‐smooth muscle actin (SMA), and PRG4. Chondrocyte aggregates were found in the subchondral bone of regions of exposed bone in sections from five individuals. The average diameter of cartilaginous aggregates was 152 µm, and the average depth of the aggregates below the surface was about 475 µm. Most aggregates were fibrocartilaginous and stained positive for type II collagen. Of interest was the finding that the cartilaginous deposits and osteoarthritic cartilage contained PRG4. Only a small percentage of chondrocytes stained positive for SMA. Cartilaginous deposits containing chondrocyte aggregates exist in subchondral bone in regions of exposed bone in some patients with advanced OA of the knee. These cells may be able to contribute to the resurfacing of the joint in certain cartilage repair procedures. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:873–883, 2007
Predicting revision risk for aseptic loosening of femoral components in total hip arthroplasty in individual patients—A finite element study
Authors: Lennon Alexander B. , Britton John R. , MacNiocaill Ruairi F. , Byrne Damien P. , Kenny Patrick J. , Prendergast Patrick J.
Published: March 2007

Advances in surgical procedure, prosthesis design, and biomaterials performance have considerably increased the longevity of total joint replacements. Preoperative planning is another step in joint replacement that may have the potential to improve clinical outcome for the individual patient, but has remained relatively consistent for a long time. One means of advancing this aspect of joint replacement surgery may be to include predictive computer simulation into the planning process. In this article, the potential of patient‐specific finite element analysis in preoperative assessment is investigated. Seventeen patient‐specific finite element models of cemented Charnley reconstructions were created, of which six were early (<10 years) revisions. Creep was simulated using a Maxwell model, and fatigue damage was simulated using an anisotropic continuum damage formulation. Account was taken of the relationship between annual loading cycles and age, and stair‐climbing loads were included using a walking to stair‐climbing cycle ratio of 9:1. Simulations for the equivalent of 10 years of loading were performed. Accumulated damage, inducible displacement, and migration were computed. Five of the six early revisions had the highest migration indicating that migration could have been used to identify early failures of these prostheses. Resultant migration showed the most significant difference between the early revised and unrevised groups (p = 0.0024). Furthermore, this trend was apparent from 1 year postimplantation (p = 0.0052). This ability to differentiate early revisions shows that computational simulation of aseptic loosening in cemented prostheses could prove clinically useful in helping surgeons optimize the preoperative plan for individual patients. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 779–788, 2007
Targeting of cell survival genes using small interfering RNAs (siRNAs) enhances radiosensitivity of Grade II chondrosarcoma cells
Authors: Kim Dae Won , Seo Sung Wook , Cho Samuel K. , Chang Seong Sil , Lee Ho Won , Lee Se Eun , Block Joel A. , Hei Tom K. , Lee Francis Y.
Published: March 2007

The main treatment for chondrosarcoma is surgical resection with a wide margin. However, there are certain chondrosarcomas, such as those found in the pelvis and the spine, which cannot be resected adequately with surgery alone. Unfortunately, most chondrosarcomas are resistant to radiation and chemotherapy. Radiation and chemotherapy are thought to kill chondrosarcoma cells by inducing apoptosis, or programmed cell death. In this article, we hypothesize that antiapoptotic gene silencing enhances radiosensitivity in chondrosarcoma cells by facilitating apoptotic pathways. We knocked down antiapoptotic genes in chondrosarcoma cells using small interfering RNAs (siRNAs). Two well‐established Grade II human chondrosarcoma cell lines were pretreated with siRNAs that specifically target mRNAs for Bcl‐2, Bcl‐xL, or XIAP. The cells were then treated with radiation. Cell death was assessed by flow cytometry. Cell survival and proliferation were measured by clonogenic survival assays. Chondrosarcoma cells exhibited radioresistance and increased the expression of Bcl‐2, Bcl‐xL, and XIAP in response to radiation. When one of the Bcl‐2, Bcl‐xL, or XIAP genes was silenced with the corresponding siRNA, radiosensitivity increased up to 9.2‐fold (p < 0.05). When two out of the three antiapoptotic mRNAs were knocked down simultaneously, there was an 11.3‐fold increase in cell death after radiation (p < 0.05). Our findings support a novel therapeutic concept that gene silencing may be used as a molecular adjuvant therapy for radioresistant sarcomas. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 820–828, 2007
Correlation between the knee adduction torque and medial contact force for a variety of gait patterns
Authors: Zhao Dong , Banks Scott A. , Mitchell Kim H. , D'Lima Darryl D. , Colwell Clifford W. , Fregly Benjamin J.
Published: March 2007

The external knee adduction torque has been proposed as a surrogate measure for medial compartment load during gait. However, a direct link between these two quantities has not been demonstrated using in vivo measurement of medial compartment load. This study uses in vivo data collected from a single subject with an instrumented knee implant to evaluate this link. The subject performed five different overground gait motions (normal, fast, slow, wide, and toe‐out) with simultaneous collection of instrumented implant, video motion, and ground reaction data. For each trial, the knee adduction torque was measured externally while the total axial force applied to the tibial insert was measured internally. Based on data collected from the same subject performing treadmill gait under fluoroscopic motion analysis, a regression equation was developed to calculate medial contact force from the implant load cell measurements. Correlation analyses were performed for the stance phase and entire gait cycle to quantify the relationship between the knee adduction torque and both the medial contact force and the medial to total contact force ratio. When the entire gait cycle was analyzed, R2 for medial contact force was 0.77 when all gait trials were analyzed together and between 0.69 and 0.93 when each gait trial was analyzed separately (p < 0.001 in all cases). For medial to total force ratio, R2 was 0.69 for all trials together and between 0.54 and 0.90 for each trial separately (p < 0.001 in all cases). When only the stance phase was analyzed, R2 values were slightly lower. These results support the hypothesis that the knee adduction torque is highly correlated with medial compartment contact force and medial to total force ratio during gait. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 789–797, 2007
Anteroposterior pelvic radiographs to assess acetabular retroversion: High validity of the “cross‐over‐sign”
Authors: Jamali Amir A. , Mladenov Kiril , Meyer Dominik C. , Martinez Alberto , Beck Martin , Ganz Reinhold , Leunig Michael
Published: March 2007

Acetabular retroversion has been proposed to contribute to the development of osteoarthritis of the hip. For the diagnosis of this condition, conventional AP pelvic radiographs may represent a reliable, easily available diagnostic modality as they can be obtained with a reproducible technique allowing the anterior and posterior acetabular rims to be visible for assessment. This study was designed to: (i) determine cranial, central, and caudal anatomic acetabular version (AV) from cadaveric specimens; (ii) establish the validity and reliability of the radiographic measurements of central acetabular anteversion; and (iii) determine the validity and reliability of the radiographic “cross‐over‐sign” to detect acetabular retroversion. Using 43 desiccated pelvises (86 acetabuli) the anatomic AVs were measured at three different transverse planes (cranially, centrally, and caudally). From these pelvises, standardized AP pelvic radiographs were obtained. To directly measure central AV, a modified radiographic method is introduced for the use of AP pelvic radiographs. The validity and reliability of this radiographic method and of the radiographic cross‐over‐sign to detect cranial acetabular retroversion were determined. The mean central and caudal anatomic AVs were approximately 20°, and the mean cranial AV was 8°. Cranial retroversion (AV < 0°) was present in 19 of 86 hips (22%). A linear correlation was found between the central and cranial AV. Below 10° of central AV, all acetabuli were cranially retroverted. Between 10° and 20°, 30% of the acetabuli were cranially retroverted, and above 20°, only 1 of 45 acetabuli was cranially retroverted. The radiographic measurement of the central AV (20.3 ± 6.5°) correlated strongly with the anatomic AV (20.1 ± 6.4°). The sensitivity of the cross‐over‐sign to detect a cranial acetabular anteversion of less than 4° was 96%, its specificity 95%, and the positive predictive and negative predictive values 90% and 98%, respectively. Both the modified radiographic anteversion measurements and the cross‐over‐sign demonstrated substantial inter‐ and intraobserver reliability. Retroversion is almost exclusively a problem of the cranial acetabulum. The cranial AV is on average 12° lower than the central AV, with the latter directly measurable from AP pelvic radiographs. A central AV of less than 10° was associated with cranial retroversion. The presence of a positive cross‐over‐sign is a highly reliable indicator of cranial AV of <4°. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 758–765, 2007
An MIS 5a to MIS 4 (or early MIS 3) environmental and climatic reconstruction from the northwest South Island, New Zealand, using beetle fossils
Authors: Burge P. I. , Shulmeister J.
Published: March 2007

A fossil beetle study is presented from the northwest coast, South Island, New Zealand. The samples were recovered from overbank deposits on a marine terrace situated 4 km east of Westport, New Zealand (41° 45' S, 171° 36' E). The age of the site is constrained to between 74 and 40 ka but discrepancies between luminescence and radiocarbon age results prevent more precise age control.

The older of two samples indicates a closed canopy Nothofagus (southern beech) forest with deep litter and dead wood on the forest floor. The younger sample yields a similar Nothofagus forest environment with subalpine affinities and nearby tussock grassland. For the older sample, mean summer and winter minimum temperatures were similar to modern values. Mean summer temperature was ca. 3.0°C cooler than modern during the younger phase while mean minimum winter temperature was ca. 5.0°C cooler than present indicating both cooling and increased seasonality. Both samples suggest a 30–40% decrease in mean annual precipitation from modern values.

Persistence of closed canopy Nothofagus forest during the period of 74–40 ka contrasts with regional pollen studies which imply widespread shrub‐land at these times. This implies that this site may have served as a glacial refugium for Nothofagus forest. Copyright © 2007 John Wiley & Sons, Ltd.
Retention indices in the analysis of food aroma volatile compounds in temperature‐programmed gas chromatography: Database creation and evaluation of precision and robustness
Authors: Bianchi Federica , Careri Maria , Mangia Alessandro , Musci Marilena
Published: March 2007

A retention index (RI) database containing 250 volatile compounds was created on a polar stationary phase column and validated for food aroma characterisation. Precision of the retention indices (RIs) was assessed by performing replicated injections of a representative number of volatiles under the same experimental conditions: differences lower than 1 U were observed for all the compounds. Robustness was evaluated by carrying out injections of the same set of volatile compounds under different experimental conditions, i. e. program temperature, column batches and instrumentation. Excellent results were obtained with a maximum difference in the RI values of 10 U. The capabilities of the created database for food aroma characterisation were finally evaluated by analysing the volatile fractions of different food matrices such as dry sausages, cheese and bread. A great number of volatile compounds were identified in the analysed samples on the basis of their RI, thus proving the usefulness of the RI collections in the field of food analysis.
Solid phase microextraction–comprehensive two‐dimensional gas chromatography–time‐of‐flight mass spectrometry for the analysis of honey volatiles
Authors: Čajka Tomáš , Hajšlová Jana , Cochran Jack , Holadová Kateřina , Klimánková Eva
Published: March 2007

Head‐space solid phase microextration (SPME), followed by comprehensive two‐dimensional gas chromatography–time‐of‐flight mass spectrometry (GC×GC–TOFMS), has been implemented for the analysis of honey volatiles, with emphasis on the optimal selection of SPME fibre and the first‐ and second‐dimension GC capillaries. From seven SPME fibres investigated, a divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) 50/30 μm fibre provided the best sorption capacity and the broadest range of volatiles extracted from the headspace of a mixed honey sample. A combination of DB‐5ms×SUPELCOWAX 10 columns enabled the best resolution of sample components compared to the other two tested column configurations. Employing this powerful analytical strategy led to the identification of 164 volatile compounds present in a honey mixture during a 19‐min GC run. Combination of this simple and inexpensive SPME‐based sampling/concentration technique with the advanced separation/identification approach represented by GC×GC–TOFMS allows a rapid and comprehensive examination of the honey volatiles profile. In this way, the laboratory sample throughput can be increased significantly and, at the same time, the risk of erroneous identification, which cannot be avoided in one‐dimensional GC separation, is minimised.