bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct hydride transfer in the reaction mechanism of quinoprotein alcohol dehydrogenases: a quantum mechanical investigation
Authors: Jongejan A. , Jongejan J. A. , Hagen W. R.
Published: October 2002

Oxidation of alcohols by direct hydride transfer to the pyrroloquinoline quinone (PQQ) cofactor of quinoprotein alcohol dehydrogenases has been studied using ab initio quantum mechanical methods. Energies and geometries were calculated at the 6‐31G(d,p) level of theory. Comparison of the results obtained for PQQ and several derivatives with available structural and spectroscopic data served to judge the feasibility of the calculations. The role of calcium in the enzymatic reaction mechanism has been investigated. Transition state searches have been conducted at the semiempirical and STO‐3G(d) level of theory. It is concluded that hydride transfer from the Cα‐position of the substrate alcohol (or aldehyde) directly to the C(5) carbon of PQQ is energetically feasible. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1732–1749, 2001
Molecular mechanics and dynamics of biomolecules using a solvent continuum model
Authors: Fogolari F. , Esposito G. , Viglino P. , Molinari H.
Published: October 2002

An easy implementation of molecular mechanics and molecular dynamics simulation using a continuum solvent model is presented that is particularly suitable for biomolecular simulations. The computation of solvation forces is made using the linear Poisson–Boltzmann equation (polar contribution) and the solvent‐accessible surface area approach (nonpolar contribution). The feasibility of the methodology is demonstrated on a small protein and a small DNA hairpin. Although the parameters employed in this model must be refined to gain reliability, the performance of the method, with a standard choice of parameters, is comparable with results obtained by explicit water simulations. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1830–1842, 2001
Prediction of infinite dilution activity coefficients of chlorinated organic compounds in aqueous solution from quantum‐chemical descriptors
Authors: Delgado Eduardo J. , Alderete Joel B.
Published: October 2002

A quantitative structure–property relationship (QSPR) model is developed to correlate the natural logarithm of infinite dilution activity coefficients, ln (γ∞), of 45 chlorinated organic compounds in aqueous solution from quantum‐chemical descriptors. The best correlation equation contains five theoretical molecular descriptors. All descriptors were obtained from the chemical structure of the compounds and have definite physical meaning corresponding to different intermolecular interactions. The model predicts ln (γ∞) with a correlation coefficients of 0.949 and a standard error of 0.442 ln  units. The obtained QSPR equation may be applied to the prediction of γ∞ of other chlorinated organic compounds not present in the data set used for the development of the present model. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1851–1856, 2001
Epidermal growth factor stimulates proton efflux from chondrocytic cells
Authors: Lui Kevin E.H. , Panchal Amiesha S. , Santhanagopal Anu , Dixon S. Jeffrey , Bernier Suzanne M.
Published: October 2002

Proton efflux from chondrocytes alters the extracellular pH and ionic composition of cartilage, and influences the synthesis and degradation of extracellular matrix. Epidermal growth factor (EGF) promotes chondrocyte proliferation during skeletal development and accumulates in the synovial fluid in rheumatoid arthritis. The purpose of this study was to investigate the effect of EGF on proton efflux from chondrocytes. When monitored using a Cytosensor microphysiometer, EGF was found to rapidly activate proton efflux from CFK2 chondrocytic cells and rat articular chondrocytes. The actions of EGF were concentration‐dependent with half‐maximal effects at 0.3–0.7 ng/ml. Partial desensitization and time‐dependent recovery of the response were observed following repeated exposures to EGF. EGF‐induced proton efflux was dependent on extracellular glucose, and inhibitors of Na+/H+ exchange (NHE) markedly attenuated the initial increase in proton efflux. The response was diminished by inhibitors of phosphatidylinositol 3‐kinase and phospholipase C, but not by inhibitors of MEK (MAPK/ERK kinase) or protein kinase A or C. Thus, EGF‐induced proton efflux involves glucose metabolism and NHE, and is regulated by a discrete subset of EGF‐activated signaling pathways. In vivo, proton efflux induced by EGF may lead to an acidic environment, enhancing turnover of cartilage matrix during development and in rheumatoid arthritis. © 2002 Wiley‐Liss, Inc.
Enhanced activity of Ca2+‐activated K+ channels by 1‐[2‐hydroxy‐3‐propyl‐4‐[(1H‐tetrazol‐5‐yl)butoxyl]phenyl] ethanone (LY‐171883) in neuroendocrine and neuroblastoma cell lines
Authors: Li Ping‐Chia , Liang Jin‐Tung , Huang Hung‐Tu , Lin Pei‐Hsuan , Wu Sheng‐Nan
Published: October 2002

The effects of LY‐171883, an orally active leukotriene antagonist, on membrane currents were examined in pituitary GH3 and in neuroblastoma IMR‐32 cells. In GH3 cells, LY‐171883 (1–300 μM) reversibly increased the amplitude of Ca2+‐activated K+ current in a concentration‐dependent manner with an EC50 value of 15 μM. In excised inside‐out patches recorded from GH3 cells, the application of LY‐171883 into cytosolic face did not modify single channel conductance of large‐conductance Ca2+‐activated K+ (BKCa) channels; however, it did increase the channel activity. The LY‐171883‐stimulated activity of BKCa channels is dependent on membrane potential, and results mainly from an increase in mean open time and a decrease in mean closed time. However, REV‐5901 (30 μM) suppressed the activity of BKCa channels and MK‐571 (30 μM) did not have any effect on it. Under the current‐clamp condition, LY‐171883 (30 μM) caused membrane hyperpolarization as well as decreased the firing rate of action potentials in GH3 cells. In neuroblastoma IMR‐32 cells, the application of LY‐171883 (30 μM) also stimulated BKCa channel activity in a voltage‐dependent manner. However, neither clofibrate (30 μM) nor leukotriene D4 (10 μM) affected the channel activity in IMR‐32 cells. Troglitazone (30 μM) decreased the channel activity, but ciglitazone (30 μM) enhanced it. This study clearly demonstrates that LY‐171883 stimulates the activity of BKCa channels in a manner unlikely to be linked to its blockade of leukotriene receptors or stimulation of peroxisome proliferator‐activated receptors. The stimulatory effects on these channels may, at least in part, contribute to the underlying cellular mechanisms by which LY‐171883 affects neuronal or neuroendocrine function. © 2002 Wiley‐Liss, Inc.
Actin machinery of phagocytic cells: Universal target for bacterial attack
Authors: Belyi Iouri F.
Published: October 2002

Uptake of microorganisms by eukaryotic cells depends on proper functioning of the actin machinery. It creates a driving force for the cell membrane deformations necessary for ingestion and killing of microbes by phagocytes. Therefore, specific alterations in the activity of the actin apparatus could be favorable for pathogenic bacteria, representing an efficient mechanism in their virulence. Such alterations are supposed to be achieved in two principle ways. One is accomplished via binding of bacterial ligands to certain surface receptors, which initiate subsequent actin cytoskeleton rearrangements. Another is to introduce cytoskeleton‐targeted products directly into eukaryotic cells and in this way modulate the activity of the actin apparatus. Indeed, Legionella and some other intracellular parasites possess ligands able to stimulate certain receptors on the surface of phagocytes and possess devices suitable for translocation of effector molecules into eukaryotic cytoplasm. The results of such events could be increased uptake of these microbes and their subsequent transportation to permit multiplication in their intracellular niche. On the contrary, representatives of Clostridium and a number of other extracellular pathogens create products which penetrate eukaryotic cells and disorganize the actin cytoskeleton network, thus making uptake of these pathogens by phagocytes impossible. Microsc. Res. Tech. 57:432–440, 2002. © 2002 Wiley‐Liss, Inc.
Are thrombocytes and platelets true phagocytes?
Authors: Meseguer José , Esteban M. Ángeles , Rodríguez Alejandro
Published: October 2002

Thrombocytes and platelets, beyond their primary function in hemostasis, seem to play an active role in inflammation. As regards their phagocytic ability, the results to date are confusing, incomplete, and somewhat contradictory. Whereas the interaction of avian thrombocytes or mammalian platelets with bacteria both in vitro and in vivo has received wide attention, almost no information exists on the topic in “lower” vertebrates. The aim of this work is to review the available information on the phagocytic properties of thrombocytes and platelets. Particular attention is payed to the ontogeny of these cells, the soluble factors involved in the inflammatory process derived from them, and their interaction with particulate material, mainly with bacteria. Microsc. Res. Tech. 57:491–497, 2002. © 2002 Wiley‐Liss, Inc.
Phosphorescent metalloporphyrins as labels in time‐resolved luminescence microscopy: Effect of mounting on emission intensity
Authors: Soini Aleksi E. , Seveus Lahja , Meltola Niko J. , Papkovsky Dmitri B. , Soini Erkki
Published: October 2002

In this study, we present an investigation of the effects of mounting media on the phosphorescence of metalloporphyrin stained microscopy samples. The samples were: (1) Platinum(II) coproporphyrin (=PtCP) stained porous Sephadex beads; (2) compact polystyrene microspheres coated with IgG‐PtCP conjugate; and (3) immunocytochemically labeled human peripheral blood neutrophils. The human neutrophils in a mixed leukocyte population were fixed, permeabilized, and then immunolabeled with PtCP conjugate of monoclonal mouse IgG directed to the intracellular antigen myeloperoxidase. The samples were mounted in twelve different mounting media and studied with quantitative time‐resolved luminescence imaging microscopy with respect to the intensity and stability of the phosphorescence signal. The results indicate that microscopy samples stained with PtCP exhibit the brightest phosphorescence emission in non‐mounted form or when mounted in non‐aqueous permanent mounting media. Microsc. Res. Tech. 58:125–131, 2002. © 2002 Wiley‐Liss, Inc.
Hg2+ affects the intracellular free Ca2+ oscillatory pattern and the correlated membrane conductance changes in Mg2+‐stimulated oocytes of the prawn Palaemon serratus
Authors: GOUDEAU MARIE , GOUDEAU HENRI
Published: October 2002

The impact of mercuric ions (Hg2+) on prawn oocytes was examined. Prawn oocytes constitute an unusual system in that they are activated at spawning by seawater Mg2+, which mediates correlated dynamic changes in intracellular free calcium concentration [(Ca2+)i] and membrane conductance associated with the meiosis resumption. Using a voltage clamp technique and intracellular calcium measurements, we observed that treatment with Hg2+ (5, 10, and 20 μM) resulted in simultaneous impairments of both (Ca2+)i and membrane current responses to external Mg2+. Treatment with Hg2+ also resulted in a gradual dose‐dependent slow increase in the baseline level of both (Ca2+)i and membrane conductance, independent of stimulation with external Mg2+. The effect of Hg2+ on (Ca2+)i and membrane conductance changes resulted from a block of the signal transduction pathway at some point before the InsP3 receptor channel involved in Ca2+ release from the endoplasmic reticulum (ER) stocks. The Hg2+‐dependent gradual increase in both (Ca2+)i and membrane conductance baseline levels may potentially result from a slow permeabi‐lization of the ER membrane, resulting in Ca2+ leaking into the cytosol. Indeed, this effect could be blocked with the cell permeable Hg2+ competitor dithiothreitol, which was able to displace Hg2+ from its intracellular target regardless of whether external Ca2+ was present or not. © 2002 Wiley‐Liss, Inc.
High‐level expression of naked DNA delivered to rat liver via tail vein injection
Authors: Maruyama H. , Higuchi N. , Nishikawa Y. , Kameda S. , Iino N. , Kazama J. J. , Takahashi N. , Sugawa M. , Hanawa H. , Tada N. , Miyazaki J. , Gejyo F.
Published: October 2002

Background

High levels of foreign gene expression in mouse hepatocytes can be achieved by rapid tail vein injection of a large volume of a naked DNA solution, the ‘hydrodynamics‐based procedure’. Rats are more tolerant of the frequent phlebotomies required for monitoring blood parameters than mice, and thus are better for some biomedical research.

Methods

We tested this technique for the delivery of a therapeutic protein in normal rats, using a rat erythropoietin (Epo) expression plasmid vector, pCAGGS‐Epo.

Results

We obtained maximal Epo expression when the DNA solution was injected in a volume of 25 ml (approximately 100 ml/kg body weight) within 15 s. We observed a dose‐response relationship between serum Epo levels and the amount of injected DNA up to 800 µg. Using quantitative real‐time PCR, the vector‐derived Epo mRNA expression was mainly detected in the liver. When a lacZ expression plasmid was injected similarly, β‐galactosidase was exclusively detected in the liver, mainly in hepatocytes. Toxicity attributable to the technique was mild and transient, as assessed by histochemical analysis. Epo gene expression and erythropoiesis occurred with Epo gene transfer in a dose‐dependent manner, and persisted for at least 12 weeks, the last time point examined. Repeated administration of the plasmid DNA also effectively led to erythropoiesis.

Conclusions

These results demonstrate that gene transfer into the liver via rapid tail vein injection can easily be achieved in the rat, which is more than 10 times larger than the mouse, and has significant value for gene function analysis in rats. Copyright © 2002 John Wiley & Sons, Ltd.
On the “largeur d'arborescence”
Authors: van der Holst Hein
Published: October 2002

Let la(G) be the invariant introduced by Colin de Verdière [J. Comb. Theory, Ser. B., 74:121–146, 1998], which is defined as the smallest integer n≥0 such that G is isomorphic to a minor of Kn×T, where Kn is a complete graph on n vertices and where T is an arbitrary tree. In this paper, we give an alternative definition of la(G), which is more in terms of the tree‐width of a graph. We give the collection of minimal forbidden minors for the class of graphs G with la(G)≤k, for k=2, 3. We show how this work on la(G) can be used to get a forbidden minor characterization of the graphs with $\nu^{\cal R}_1$(G)≤3. Here, $\nu^{\cal R}_1$(G) is another graph parameter introduced in the above cited paper. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 24–52, 2002
Microwave applications in radiolabelling with short‐lived positron‐emitting radionuclides
Authors: Stone‐Elander Sharon , Elander Nils
Published: October 2002

The use of microwave dielectric heating to reduce reaction times in organic transformations is rapidly increasing worldwide. Besides the time gains from simply performing reactions faster, other advantages have been noted, e.g. cleaner reaction mixtures due to decreased sample decomposition and altered product distributions as well as improved chemical flexibility due to the ability to accelerate typically sluggish reactions of less activated substrates. Microwave applications in radiolabelling tracers for positron emission tomography, paralleling and sometimes preceding developments in other areas of microwave‐enhanced chemistry, are reviewed here. Copyright © 2002 John Wiley & Sons, Ltd.
Radiosynthesis of 1‐(4‐(2‐[18F]fluoroethoxy)benzenesulfonyl)‐3‐butyl urea: a potential β‐cell imaging agent
Authors: Schirrmacher Ralf , Weber Michael , Schmitz Alexander , Shiue Chyng‐Yann , Alavi Abass A. , Feilen Peter , Schneider Stefan , Kann Peter , Rösch Frank
Published: October 2002

Tolbutamide (1) is a sulfonurea agent used to stimulate insulin secretion in type 2 diabetic patients. Its analogue 1‐(4‐(2‐[18F]fluoroethoxy)benzenesulfonyl)‐3‐butyl urea (3) was synthesized in overall radiochemical yields of 45% as a potential β‐cell imaging agent. Compound 3 was synthesized by 18F‐fluoroalkylation of the corresponding hydroxy precursor (2) with 2‐[18F]fluoroethyltosylate in DMF at 120°C for 10 min followed by purification with HPLC in a synthesis time of 50 min. Insulin secretion experiments of the authentic 19F‐standard compound on rat islets showed that the compound has a similar stimulating effect on insulin secretion as that of tolbutamide (1). The partition coefficient of compound 3 between octanol/water was determined to be 1.3±0.3 (n=5). Copyright © 2002 John Wiley & Sons, Ltd.
Fine structure and probable function of ring organs in the mite Histiostoma feroniarum (Acari: Actinotrichida: Acaridida: Histiostomatidae)
Authors: Witaliński Wojciech , Liana Marcin , Alberti Gerd
Published: October 2002

Histiostoma feroniarum, like other histiostomatid mites, possesses peculiar ring organs that are visible under the light microscope as ventrally located, characteristic rings of sclerotized cuticle. The ring organ is composed of three elements: a disc of modified cuticle, ring organ cells located underneath the disc, and an “empty” chamber frequently visible between the cuticular disc and the cells. The cuticle of the disc is not perforated and differs from the surrounding unmodified cuticle as revealed by special staining developed for light microscopy and by electron microscopy. The ring organ cells show a polarity, with a practically smooth apical surface and an extremely folded basal membrane. The basal invaginations reach the apical cell portion, where they form tubular canaliculi distributed beneath the apical cell membrane. The cytoplasm contains many mitochondria, which are usually in contact with the cell membrane invaginations. Structurally, the ring organ cells closely resemble the transport cells described in osmoregulatory organs both in water‐inhabiting and terrestrial arthropods. Thus, our results support earlier suggestions of an osmoregulatory function performed by sclerotized rings (=ring organs), as an adaptation to aqueous environments. A possible homology with similar organs of other mites is discussed. J. Morphol. 253:255–263, 2002. © 2002 Wiley‐Liss, Inc.
Neurogenesis in the mossy chiton, Mopalia muscosa (gould) (polyplacophora): Evidence against molluscan metamerism
Authors: Friedrich Stefan , Wanninger Andreas , Brückner Martin , Haszprunar Gerhard
Published: October 2002

Neurogenesis in the chiton Mopalia muscosa (Gould, 1846) was investigated by applying differential interference contrast microscopy, semithin serial sectioning combined with reconstruction techniques, as well as confocal laser scanning microscopy for the detection of fluorescence‐conjugated antibodies against serotonin and FMRFamide. The ontogeny of serotonergic nervous structures starts with cells of the apical organ followed by those of the cerebral commissure, whereas the serotonergic prototroch innervation, pedal system, and the lateral cords develop later. In addition, there are eight symmetrically arranged serotonergic sensory cells in the dorsal pretrochal area of the larva. FMRFamide‐positive neural elements include the cerebral commissure, specific “ampullary” sensory cells in the pretrochal region, as well as the larval lateral and pedal system. In the early juvenile the cerebral system no longer stains with either of the two antibodies and the pedal system lacks anti‐FMRFamide immunoreactivity. Outgroup comparison with all other molluscan classes and related phyla suggests that the cord‐like, nonganglionized cerebral system in the Polyplacophora is a reduced condition rather than a primitive molluscan condition. The immunosensitivity of the pedal commissures develops from posterior to anterior, suggesting independent serial repetition rather than annelid‐like conditions and there is no trace of true segmentation during nervous system development. Polyplacophoran neurogenesis and all other available data on the subject contradict the idea of a segmented molluscan stem species. J. Morphol. 253:109–117, 2002. © 2002 Wiley‐Liss, Inc.
Spermatophore transfer in the hermit crab Clibanarius vittatus (crustacea, anomura, diogenidae)
Authors: Hess Gregory S. , Bauer Raymond T.
Published: October 2002

Although mating has been described in several hermit crab species, the mechanics of spermatophore transfer have not previously been demonstrated. Evidence from pleopod and gonopore morphology, video observations, and inseminated females indicates that in Clibanarius vittatus the male applies a spermatophoric mass directly onto the female via the gonopores rather than with modified pleopods 1–2 (gonopods) and/or genital papillae as in many other decapods. The single second pleopod of males of C. vittatus has a simple endopod with no apparent modifications for sperm transfer. There are no genital papillae extending from the male gonopores. The globular spermatophores are aligned in rows surrounded by a seminal secretion in the male ducts (vasa deferentia that terminate in ejaculatory ducts opening to the exterior via the gonopores). During copulation, described from time‐lapse video recordings, the ventral surface of the last thoracic segment of the male, bearing the gonopores, was apposed to the ventral cephalothorax of the female. A massive amount of seminal secretion containing spermatophore ribbons, termed here the spermatophoric mass and described for the first time in a hermit crab species, was observed covering the sternites and coxae of pereopods 1–5 of a recently copulated female. It is suggested that during copulation the male emits the contents of the ejaculatory ducts directly onto the female without the aid of gonopods or genital papillae. Although spermatophore transfer is simple in C. vittatus, the presence of modified anterior pleopods or elongate genital papillae (sexual tubes) in other paguroidean species suggests the possibility of a more complex insemination process in these other hermit crabs. J. Morphol. 253:166–175, 2002. © 2002 Wiley‐Liss, Inc.
Assessment of patellofemoral relationships using kinematic MRI: Comparison between qualitative and quantitative methods
Authors: Ward Samuel R. , Shellock Frank G. , Terk Michael R. , Salsich Gretchen B. , Powers Christopher M.
Published: October 2002

Purpose

To compare the level of agreement between quantitative and qualitative methods in determining patellofemoral relationships, since controversy exists regarding the use of quantitative vs. qualitative criteria to interpret images of the patellofemoral joint (PFJ) obtained using kinematic magnetic resonance (MR) imaging.

Materials and Methods

One hundred twenty mid‐patellar axial plane images obtained using kinematic MR imaging from fifteen subjects were randomly selected for analysis. MR images represented various knee flexion angles ranging from 0 to 60 degrees. Quantitative analysis (bisect offset and patellar tilt angle) was performed by two examiners using a computer‐assisted software program. Based on data from previously published literature, MR images were characterized as demonstrating normal, medial, or lateral patellar subluxation, and/or normal, medial, or lateral tilt. Using similar categories, two different examiners experienced in reading MR images of the PFJ then applied qualitative criteria to the same images.

Results

The average agreement between the quantitative and qualitative assessments of horizontal patellar displacement and patellar tilt ranged from poor to moderate (Kappa coefficient values of 0.27 and 0.45, respectively). Quantitative and qualitative techniques demonstrated acceptable intra‐ and inter‐observer reliability.

Conclusion

These findings indicate that the use of quantitative criteria does not compare well to qualitative criteriain the analysis of kinematic MR images of the PFJ. One explanation for this discrepancy relates to the fundamental difference between the techniques. That is, quantitative measurements are based on the use of osseous landmarks, while the qualitative assessments tend to rely on a description of patellofemoral relationships based on joint surfaces. J. Magn. Reson. Imaging 2002;16:69–74. © 2002 Wiley‐Liss, Inc.
Intrahepatic arterioportal fistula: Demonstration by dynamic 3D magnetic resonance angiography in under four seconds
Authors: Balci N. Cem , Onat Levent , Karaman Kutlay , Şirvancı Mustafa
Published: October 2002

We report a case of a 35‐year‐old patient with clinical symptoms of portal hypertension that underwent dynamic contrast‐enhanced 3D magnetic resonance angiography (MRA) of the abdomen. On breath‐hold dynamic contrast‐enhanced MRA in less than 4 seconds, contrast passage from the arterial to the portal system was successfully demonstrated. Patient was managed according to MRA findings. J. Magn. Reson. Imaging 2002;16:94–96. © 2002 Wiley‐Liss, Inc.
In vivo animal functional MRI: Improved image quality with a body‐adapted mold
Authors: Landuyt Willy , Sunaert Stefan , Farina Davide , Meijerink Martijn , Béatse Eric , Van Hecke Paul , Hermans Robert , Marchal Guy , Lambin Philippe , Bosmans Hilde
Published: October 2002

Purpose

To reduce functional magnetic resonance imaging (fMRI) susceptibility distortion at the air/tissue interphase in animal experiments.

Materials and Methods

We investigated the applicability of a body‐adaptable flexible mold consisting of a fast‐setting alginate. This technique was implemented for subcutaneous growing tumors in rats and for the brains of monkeys.

Results

The T2*‐weighted gradient‐echo, echo‐planar imaging (GE‐EPI) data obtained with the body‐adapted mold showed a reduction of susceptibility artifacts and improved image quality. With both rat tumor and monkey brain, an optimized match with the anatomical T1 images was possible.

Conclusion

The present mold methodology is a rapid, easy, and inexpensive way to reduce magnetic susceptibility during animal GE‐EPI. J. Magn. Reson. Imaging 2002;16:224–227. © 2002 Wiley‐Liss, Inc.
Simultaneous real‐time visualization of the catheter tip and vascular anatomy for MR‐guided PTA of iliac arteries in an animal model
Authors: Buecker Arno , Adam Gerhard B. , Neuerburg Joerg M. , Kinzel Sylvia , Glowinski Arndt , Schaeffter Tobias , Rasche Volker , van Vaals Joop J. , Guenther Rolf W.
Published: October 2002

Purpose

To examine the feasibility of simultaneous MR real‐time active tip tracking and near real‐time depiction of the vascular anatomy for percutaneous angioplasty of iliac arteries under MR guidance.

Materials and Methods

Nine surgically created stenoses of external iliac arteries in pigs were dilated with MR‐compatible balloon catheters (Cordis, Roden, The Netherlands). These catheters were equipped with a microcoil for active tracking of the catheter tip with an in‐plane update rate of 10 positions per second. The procedures were performed on an interventional 1.5 T Gyroscan ACS‐NT scanner (Philips, Best, The Netherlands). Real‐time calculation of images acquired by radial k‐space filling was performed on a specially designed backprojector exploiting the sliding window reconstruction technique (Philips Research Laboratories, Hamburg, Germany). The image update rate was 20 frames per second using a radial gradient‐echo technique (TR = 12 msec, TE = 3.3 msec, 300 radials). MR angiography and X‐ray digital subtraction angiography on the X‐ray system positioned in‐line next to the interventional MR system served as control for the angioplasty results.

Results

Real‐time guidance and positioning of the balloon catheters was possible. The actual position of the catheter tip was indicated in the MR images without any time delay for the reconstruction of the anatomical MR images, which were updated with a rate of 20 frames per second. This yielded a combination of a roadmap and fluoroscopy image, in which the catheter position and the anatomical background image both were continuously updated in real time. Six out of nine stenoses were successfully dilated. The effects of the angioplasty could be visualized by the real‐time MR technique, as was proven by X‐ray digital subtraction angiography.

Conclusion

Active tip tracking simultaneous with MRI of the vascular anatomy—both in real time—is possible with the applied technique, enabling MR‐guided percutaneous dilatation (PTA) of iliac arteries. J. Magn. Reson. Imaging 2002;16:201–208. © 2002 Wiley‐Liss, Inc.
Initial experience with the intravascular contrast agent NC100150‐injection (Clariscan®) for breath‐hold and navigator‐gated magnetic resonance coronary artery imaging
Authors: Bunce Nicholas H. , Keegan Jennifer , Gatehouse Peter D. , Moon James C.C. , Firmin David N. , Hoffmann Volker , Pennell Dudley J.
Published: October 2002

Purpose

To examine magnetic resonance coronary artery imaging after NC100150‐Injection.

Materials and Methods

Breath‐hold and navigator‐gated images were acquired in five patients.

Results

Breath‐hold image quality, coronary artery‐fat SDNR, and coronary artery SNR improved. Respiratory artifacts due to reduced liver signal intensity degraded navigator‐gated image quality.

Conclusion

NC100150‐Injection improves breath‐hold coronary artery imaging. Navigator‐gated acquisitions should use techniques that are insensitive to T2* effects. J. Magn. Reson. Imaging 2002;16:217–223. © 2002 Wiley‐Liss, Inc.
Imaging articular cartilage defects in the ankle joint with 3D fat‐suppressed echo planar imaging: Comparison with conventional 3D fat‐suppressed gradient echo imaging
Authors: Ba‐Ssalamah Ahmed , Schibany Nadja , Puig Stefan , Herneth Andreas M. , Noebauer‐Huhmann Iris M. , Trattnig Siegfried
Published: October 2002

Purpose

To shorten the examination time for articular cartilage imaging, using a recently developed three‐dimensional (3D) multishot echo planar imaging (EPI) sequence with fat saturated (FS), compared to aconventional 3D fat‐saturated spoiled gradient echo sequence (3D FS GRE).

Material and Methods

There were 32 consecutive patients with ankle joint disorders who underwent magnetic resonance imaging (MRI) in a 1.0‐T unit. Hyaline cartilage was imaged with a 3D FS EPI sequence and a 3D FS GRE sequence. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, contrast‐to‐noise ratios (CNRs) of cartilage vs. joint fluid and bone marrow were measured.

Results

The 3D FS EPI sequence provided a high CNR between cartilage and subchondral bone, similar to that of the 3D FS GRE sequence. The CNR between cartilage and effusion was significantly lower on the 3D EPI sequence due to the higher signal intensity of fluid. Both sequences were equal in lesion detection ability. The image quality of the 3D FS GRE sequence was slightly higher than that of the 3D FS EPI, but the difference was not statistically significant.

Conclusion

We conclude that the 3D FS EPI sequence is comparable to the 3D FS GRE sequence in the detection of cartilage lesions, with the additional advantage of reduction in scan time by a factor of 4. J. Magn. Reson. Imaging 2002;16:209–216. © 2002 Wiley‐Liss, Inc.
BOLD fMRI of the visual cortex: Quantitative responses measured with a graded stimulus at 1.5 Tesla
Authors: Mohamed Feroze B. , Pinus Alexander B. , Faro Scott H. , Patel Dhawal , Tracy Joseph I.
Published: October 2002

Purpose

To measure and quantitatively characterize an activity generated by the neurons of the visual cortex (VC) in response to graded luminous intensity contrast stimuli using a 1.5 Tesla scanner.

Materials and Methods

Functional magnetic resonance imaging (fMRI) of the vc with the intrinsic blood oxygena‐tion level dependent (BOLD) mechanism was performed by using a paradigm with a 5 × 5 flashing checkerboard pattern flickering eight times per second at eight luminance contrasts presented in a randomized order. The changes of the luminance contrast were obtained by varying the luminance intensity of the white checkerboard squares. Each of eight trials, corresponding to eight luminance contrasts, consisted of six “rest” and six “activation” epochs, repeated five times, amounting to 60 measurement periods per trial. During each epoch, 10 contiguous oblique axial‐to‐coronal slices covering the calcarine fissure region and parallel to a line through the anterior‐posterior commissure (AC‐PC) markers were acquired using a gradient‐recalled echo planar imaging (GRE‐EPI) sequence.

Results

The measurements showed changes in the activation extent in the VC following the stimulus' rising luminance intensity contrast. In addition, the fMRI signal in those activated areas present throughout all eight trials, referred to as “common” voxels in this report, showed an increasing trend as a function of the rising luminance intensity contrast.

Conclusion

These results suggest that the processes of the neuronal recruitment that affects the extent and number of activated neurons, and the neuronal enhancement that defines the magnitude of the neuronal activation are dependent on the luminance intensity contrast. These changes can be visualized and quantified using BOLD fMRI at 1.5 Tesla. J. Magn. Reson. Imaging 2002;16:128–136. © 2002 Wiley‐Liss, Inc.
Identification of methyl salicylate as the principal volatile component in the methanol extract of root bark of Securidaca longepedunculata Fers
Authors: Jayasekara T. K. , Stevenson P. C. , Belmain S. R. , Farman D. I. , Hall D. R.
Published: October 2002

Securidaca longepedunculata Fers (Polygalaceae) is commonly used as a medicine in many parts of Africa and shows promise for protecting stored grain against insect pests. Analysis of a methanol extract of the root bark by gas chromatography linked to mass spectrometry (GC/MS) showed a major component accounting for over 90% of the volatile material. This was identified as methyl 2‐hydroxybenzoate (methyl salicylate) by comparison of the GC retention times and mass spectrum with those of synthetic standards. This conflicts with an earlier report that the major component is methyl 4‐hydroxybenzoate. Two minor components had mass spectra characteristic of 2‐hydroxybenzoate esters and were identified as methyl 2‐hydroxy‐6‐methoxybenzoate and its benzyl analogue, again conflicting with an earlier report. Copyright © 2002 John Wiley & Sons, Ltd.
Reactivation of human herpesvirus 6 and 7 in pregnant women
Authors: Ohashi Masahiro , Yoshikawa Tetsushi , Ihira Masaru , Suzuki Kyoko , Suga Sadao , Tada Shin , Udagawa Yasuhiro , Sakui Hisataka , Iida Keiji , Saito Yumiko , Nisiyama Yukihiro , Asano Yoshizo
Published: October 2002

To elucidate the roles of human herpesvirus (HHV)‐6 and ‐7 in pregnant women, peripheral blood samples and genital tract secretions were collected serially from pregnant women, and both serological testing and polymerase chain reaction (PCR) were carried out to detect viral DNA in the secretions. HHV‐6 or HHV‐7 Immunoglobulin(Ig)M antibodies were not detected in 432 plasma samples collected from pregnant women and cord blood, but IgG antibodies against both viruses were detected in all plasma samples. Significant increases in HHV‐6 and HHV‐7 IgG antibodies were observed in two (1.6%) and three (2.4%) pregnant women respectively of a total of 123 cases. HHV‐6 DNA was detected in the genital tract in three (3.7%) of 82 pregnant women at the first trimester, and in 10 (12.2%) of the same women in the third trimester. The detection rate in the third trimester was significantly higher than that in the first trimester (P = 0.043). Although HHV‐7 DNA was detected in the genital tract of two (2.7%) and seven (9.6%) pregnant women of a total of 73 during the first and third trimesters respectively, there was no statistical difference in the detection rate of the viral DNA between the trimesters. Because a significant increase in HHV‐6 IgG antibodies was detected in only two pregnant women, it was not possible to carry out statistical analysis to determine the relationship between HHV‐6 infection and associated clinical features. Although there was a significant increase in HHV‐7 antibody titers in three pregnant women, a positive correlation between the virus infection and the clinical features was not demonstrated. There was no statistical association between virus shedding in the genital tract and the clinical features examined in this study. J. Med Virol. 67:354–358, 2002. © 2002 Wiley‐Liss, Inc.
Sustained high proportion of zidovudine‐resistant HIV variants despite prolonged substitution of zidovudine by other nucleoside reverse transcriptase inhibitors
Authors: Bélec Laurent , Legoff Jérôme , Si‐Mohamed Ali , Andréoletti Laurent , Mbopi‐Kéou François‐Xavier , Kolberg Janice , Matta Mathieu , Detmer Jill , Piketty Christophe , Kazatchkine Michel D.
Published: October 2002

The consequences of zidovudine (ZDV) replacement by other nucleoside reverse transcriptase inhibitors on the expression of resistance mutations at codons 215 and 41 of the reverse transcriptase (RT) gene was investigated prospectively in 66 patients harboring mutant genotypes who were changed to an effective two‐ or three‐drug combination antiretroviral regimen. Quantitation of mutant (MUT) viral populations at codon 215 by means of RT‐PCR with differential hybridization of amplicons specific for MUT and wild (WT) variants revealed no difference in the proportion of 215 MUT variants prior to (93.5 ± 2.4%) and 12 to 20 months after (96.9 ± 1.9%) ZDV replacement, independently of a therapeutic change for stavudine. The fitness of the variants harboring the ZDV‐resistant MUT 215 genotype following drug withdrawal was calculated to be 96 to 99% of that of the variants harboring the WT 215 genotype. The apparent stability of ZDV‐resistant variants in the study population may have two main complementary explanations: persistent selective pressure secondary to partial cross‐resistance due to the new regimens given after the therapeutic alteration and suppression of viral replication after the therapeutic alteration that could have hampered the replacement of less fit variants by fitter variants. These findings indicate that, at least within 15 months following discontinuation of ZDV, an effective antiretroviral therapy is insufficient to allow for ZDV‐resistant strains to disappear, and thus to allow for the safe re‐introduction of the drug. J. Med. Virol. 68:1–6, 2002. © 2002 Wiley‐Liss, Inc.
Drift in the hypervariable region of the hepatitis C virus during 27 years in two patients
Authors: Gao Guang , Buskell Zelma , Seeff Leonard , Tabor Edward
Published: October 2002

Serial serum samples were obtained over a 27‐year period from a hepatitis C virus (HCV)‐infected patient and from a nurse who appeared to become infected by this patient. The hypervariable region 1 (HVR1) and 5′noncoding region (5′NCR) of the HCV genome were amplified from each serum sample by polymerase chain reaction (PCR) and cloned. In the first serum specimen from the patient and the first two serum specimens from the nurse, most of the 20 clones from each serum sample had one common sequence in the HVR1 gene. All later serum samples contained a heterogeneous mixture of HCV quasispecies. The uniformity of the HVR1 sequence in the early samples and the emergence of greater diversity in later serum samples is consistent with the apparent transmission of HCV between the patient and nurse and the eventual emergence of other quasispecies as the virus replicated in the new host. In addition, the immune globulin given to the nurse may have been responsible for some of the HCV quasispecies changes observed in her serum. J. Med. Virol. 68: 60–67, 2002. © 2002 Wiley‐Liss, Inc.
Comparison of fresh and cryopreserved porcine ventral mesencephalon cells transplanted in A rat model of Parkinson's disease
Authors: Jacoby Douglas B. , Lindberg Charles , Ratliff Judson , Wetzel Kristie , Stewart Gregory R. , Dinsmore Jonathan
Published: October 2002

To evaluate whether cryopreservation of porcine ventral mesencephalon cells influences graft survival and function in vivo, we have transplanted either freshly prepared or cryopreserved cells into the striatum of 6‐hydroxydopamine‐lesioned rats. A single cell suspension of porcine ventral mesencephalon cells from the same isolation either was stored at 4°C and transplanted the next day or was cryopreserved for 4 weeks in liquid nitrogen vapor. The cryopreserved cells were then rapidly thawed, rinsed, and transplanted in the same manner as the fresh cells, with the same dose of viable cells. All animals received daily injections of cyclosporin A to prevent xenograft rejection. To monitor graft function, amphetamine‐induced rotation was measured every 3 weeks between 6 and 15 weeks posttransplantation. After sacrifice at 15 weeks posttransplantation, histological methods were used to compare fresh cell and cryopreserved cell transplants with respect to graft survival, differentiation and integration, and host immune response. Cryopreserved cells were found to be either equivalent or in some cases superior to fresh cells with respect to rotational correction, graft survival, graft volume, numbers of graft‐derived dopaminergic neurons, and host immune responses. In conclusion, the results indicate that it is feasible to cryopreserve porcine ventral mesencephalon cells for long‐term storage of cells prior to transplantation in an animal model of Parkinson's disease. © 2002 Wiley‐Liss, Inc.
Effect of geranylgeranylaceton on cellular damage induced by proteasome inhibition in cultured spinal neurons
Authors: Kikuchi Seiji , Shinpo Kazuyoshi , Takeuchi Masayoshi , Tsuji Sachiko , Yabe Ichiro , Niino Masaaki , Tashiro Kunio
Published: October 2002

We investigated the effect of two proteasome inhibitors, lactacystin and epoxomicin, on cultured spinal cord neurons. The incubation of spinal neurons with proteasome inhibitors for 24 hr induced neurotoxicity in a dose‐dependent manner. We found motor neurons to be more vulnerable to proteasome‐induced neurotoxicity than nonmotor neurons. The staining of cell bodies in treated motor neurons was markedly disrupted and showed characteristic granular patterns. Proteasome‐induced neurotoxicity is accompanied by apoptotic nuclear changes, posttranslational modification of the cellular proteins, generation of intracellular free radicals, reduction in the amount of reduced glutathione, and mitochondrial dysfunction. Neurotoxicity was reduced by the administration of low concentrations (1–100 nM) of geranylgeranylacetone (GGA), which is widely used as an antiulcer drug, although higher concentrations of this drug produced neurotoxicity in spinal cord neurons. GGA was found to induce the expression of heat shock protein 70 as well as thioredoxin, which may partly contribute to the protective effect of GGA. These data suggest that the inhibition of proteasome may play a role in the mechanism of neurodegenerative diseases of the spinal cord, such as amyotrophic lateral sclerosis, and that the use of GGA may be effective in the treatment of these conditions. © 2002 Wiley‐Liss, Inc.
Relationship between organizational justice and employee work outcomes: a cross‐national study
Authors: Lam Simon S. K. , Schaubroeck John , Aryee Samuel
Published: October 2002

This study examined the influence of organizational justice perceptions on employee work outcome relationships as moderated by individual differences that are influenced by societal culture. Power distance, but not country or individualism, moderated the relationships between perceived justice and satisfaction, performance, and absenteeism. The effects of perceived justice on these outcomes were stronger among individuals scoring lower on power distance index, and most of these study participants were in the U.S. (versus Hong Kong) sample. Limitations of the study and the implications of the findings for managing cross‐culturally are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Social value orientation, organizational goal concerns and interdepartmental problem‐solving behavior
Authors: Nauta Aukje , De Dreu Carsten K. W. , van der Vaart Taco
Published: October 2002

In a study of 11 organizations among 120 manufacturing, planning and sales employees, support was found for the hypothesis that a prosocial value orientation—as a personality trait—increases the likelihood that employees show a high concern for the goals of other departments. This concern, combined with a high concern for own goals, furthermore appeared to increase the likelihood of problem‐solving behavior during interdepartmental negotiations. Measures of goal concerns were attained, firstly, by asking employees how important they found six specific organizational goals and, secondly, by assessing which goals were found most important by members of which department. The results of this study suggest that problem solving can be induced by selecting or developing prosocial employees, because a prosocial value orientation increases the likelihood of having broad role orientations, in which employees not only care for goals characteristic of their own department, but also for goals of other departments. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectral analysis of liquid ammonia and aqueous solution of ammonia
Authors: Ujike Tomoko , Tominaga Yasunori
Published: October 2002

The intramolecular vibrational region of the Raman spectra of liquid ammonia and aqueous solution of ammonia was studied. We propose an interpretation of these spectra assuming the dynamic structures made by hydrogen bonds. The normal mode wavenumbers of ammonia monomer, ammonia dimer and ammonia–water complex were calculated by the GF matrix method. These wavenumbers almost fit the spectral peaks. For liquid ND3 and ND3–D2O solution, the spectra are also explained in the same way. Copyright © 2002 John Wiley & Sons, Ltd.
Temperature‐dependent Raman study of L‐arginine hydrochloride monohydrate single crystal
Authors: Lima R. J. C. , Freire P. T. C. , Sasaki J. M. , Melo F. E. A. , Mendes Filho J.
Published: October 2002

Polarized Raman spectra of L‐arginine hydrochloride monohydrate single crystal were studied at temperatures ranging from 295 to 10 K. The behavior of the linewidth, wavenumber and intensity of several bands is discussed and related to some particular vibrational modes associated with hydrogen bonds or even to other vibrations, such as CN, CCC, CCN and CH vibrations. The disappearance of some bands in the lattice vibrational region was associated with a phase transition undergone by the crystal between 100 and 110 K. Copyright © 2002 John Wiley & Sons, Ltd.
A Raman study of the lithium insertion process in vanadium pentoxide thin films deposited by atomic layer deposition
Authors: Baddour‐Hadjean R. , Golabkan V. , Pereira‐Ramos J. P. , Mantoux A. , Lincot D.
Published: October 2002

Micro‐Raman spectrometry was applied to the characterization of the LixV2O5 phases (0 ≤ x ≤ 1.8) electrochemically produced from V2O5 thin films prepared by atomic layer deposition (ALD). An electrochemical study showed that V2O5 ALD films constitute attractive positive electrodes for rechargeable lithium microbatteries. The good homogeneity and crystallinity of the films allowed us to obtain high‐resolution Raman spectra and to follow their transformation as lithium insertion proceeds. Specific Raman fingerprints were obtained for the successive α, ε, δ and γ phases, and structural reversibility was evidenced for lithium uptake >1. Copyright © 2002 John Wiley & Sons, Ltd.