bluuebunny/crossref_metadata_2025 huggingface dataset:
Elucidation of the fragmentation pathways of azaspiracids, using electrospray ionisation, hydrogen/deuterium exchange, and multiple‐stage mass spectrometry
Authors: Díaz Sierra Mónica , Furey Ambrose , Hamilton Brett , Lehane Mary , James Kevin J.
Published: December 2003

Collision‐induced dissociation (CID) mass spectra were generated for azaspiracids using electrospray ionisation (ESI), and hydrogen/deuterium (H/D) exchange was used to ascertain the number and type of replaceable hydrogens in the three predominant azaspiracid toxins. H/D exchange was conveniently achieved using deuterated solvents for liquid chromatography (LC). Using ion‐trap mass spectrometry, multiple‐stage CID experiments (MSn) on the protonated and fully exchanged ions were performed to decipher characteristic fragmentation pathways. The precursor and product ions from azaspiracids lost up to five water molecules from different regions during MSn experiments and it was possible to distinguish between the water losses from different molecular regions. These studies confirmed that the first water‐loss ion in the spectra of azaspiracids resulted from dehydration at the vicinal diol at C20–C21. Five MS dissociation pathways were identified that resulted from fragmentation of the carbon skeleton of azaspiracids producing nitrogen‐containing ions. Two pathways, involving cleavage of the E‐ring and C27–C28, gave ions that were found in all azaspiracids. Three pathways, A‐ring, C‐ring and C19–C20 cleavages, were useful for distinguishing between azaspiracid analogues. The same product ions from backbone fragmentation were also observed using hybrid quadrupole time‐of‐flight mass spectrometry (QqTOFMS). The fragmentation of the A‐ring was the most facile and was exploited in the development of LC/MSn methods for the analysis of azaspiracids. Copyright © 2003 John Wiley & Sons, Ltd.
Alterations in primary afferent input to substantia gelatinosa of adult rat spinal cord after neonatal capsaicin treatment
Authors: Yang Kun , Furue Hidemasa , Fujita Tsugumi , Kumamoto Eiichi , Yoshimura Megumu
Published: December 2003

Primary afferent fibers are divided into three main subgroups: Aβ‐, Aδ‐, and C‐fibers. Morphological studies have demonstrated that neonatal capsaicin treatment (NCT) depletes C‐fiber inputs in the spinal dorsal horn; the electrophysiological features of the NCT‐induced changes, however, remain unclear. This issue was addressed by performing whole‐cell voltage‐clamp recordings from substantia gelatinosa (SG) neurons in dorsal root‐attached spinal cord slices. When estimated from excitatory postsynaptic currents (EPSCs) evoked by stimulating primary afferent fibers, 24 (49%) of 49 neurons examined exhibited C‐fiber EPSCs that were either monosynaptic (n = 15) or polysynaptic (n = 9) in origin; only two of the neurons had Aβ‐fiber responses. In NCT rats, however, SG neurons exhibiting C‐fiber‐mediated EPSCs decreased to 7% (3 of 41 neurons tested), whereas Aβ‐fiber EPSCs were observed in 21 (51%) of the neurons, and 14 (67%) of them exhibited monosynaptic ones. There was no change in the cell proportion having Aδ‐fiber innervation after NCT. Our electrophysiological data suggest that NCT diminishes primary afferent C‐fiber inputs while enhancing Aβ‐fiber direct innervation in the SG in adulthood. © 2003 Wiley‐Liss, Inc.
Distribution of polysialylated neural cell adhesion molecule in rat septal nuclei and septohippocampal pathway: Transient increase of polysialylated interneurons in the subtriangular septal zone during memory consolidation
Authors: Foley Andrew G. , Rønn Lars C.B. , Murphy Keith J. , Regan Ciaran M.
Published: December 2003

During memory consolidation neuroplastic events in the mediotemporal corticohippocampal pathway are accompanied by transient increases in the frequency of neurons expressing polysialylated neural cell adhesion molecule (NCAM PSA), a posttranslational modification associated with morphofunctional change. As a bidirectional pathway between the hippocampus and the septal nuclei also influences memory processing, we have determined the distribution of NCAM PSA within this system before and after learning in the adult Wistar rat. The most intense NCAM PSA immunoreactivity was observed in the medial and triangular septal nuclei, regions that regulate hippocampal theta rhythm during memory consolidation. Within the fimbria, NCAM PSA was expressed only in a subpopulation of fibres, most likely cholinergic projections from the medial septum to the hippocampus. Grey level analysis or direct cell counting revealed no learning‐specific change in NCAM PSA expression in these septal subregions after avoidance conditioning or spatial training. A population of discrete polysialylated neurons in the subtriangular septal zone, however, exhibited a transient twofold frequency increase at 12 hr after training in either task. Immunohistochemical analysis revealed these cells to be gamma–aminobutyric acid (GABAergic) interneurons co‐expressing vasoactive intestinal peptide. The unique location of these interneurons is proposed to provide a natural plexus by which bidirectional communication between the septum and hippocampus may be modified during memory consolidation. © 2003 Wiley‐Liss, Inc.
Mechanism of preventive action of Viburnum dilatatum Thunb (gamazumi) crude extract on oxidative damage in rats subjected to stress
Authors: Iwai Kunihisa , Onodera Akio , Matsue Hajime
Published: December 2003

The fruit of Viburnum dilatatum Thunb (gamazumi) has been shown to prevent oxidative injury induced by water immersion restraint stress (WIRS) in rats. In this study the effect of gamazumi crude extract (GCE) on antioxidant enzymatic activities in the plasma, liver and stomach of rats with WIRS was investigated to elucidate the mechanism of prevention of oxidative injury. Ulcer formation and lipid peroxidation were inhibited in rats supplied GCE for 2 weeks in comparison with rats supplied water. Although the activities of plasma, hepatic and gastric antioxidant enzymes in rats given water were decreased by WIRS, only slight changes were observed in rats given GCE. There was no difference in enzymatic activities between the water and GCE groups not subjected to WIRS. Furthermore, ferrous ascorbate‐induced oxidation in hepatic homogenate from rats given GCE was inhibited. These results suggest that ingestion of GCE does not induce antioxidant enzymes and that the absorbed antioxidant components of GCE have a direct effect on oxidative injury in the body. Copyright © 2003 Society of Chemical Industry
The evolution of lung cancer screening
Authors: Wilkinson Neal W. , Loewen Gregory M. , Klippenstein Donald L. , Litwin Alan M. , Anderson Timothy M.
Published: December 2003

In the 1970s, four trials failed to demonstrate any mortality reduction using a combination of chest X‐ray (CXR) and/or sputum cytology. The recent early lung cancer action project (ELCAP) demonstrated that modern screening is capable of detecting Stage I lung cancers. Bronchial epithelial changes leading up to cancers are now being understood to include histologic changes and genetic alterations. Emerging molecular markers detected in sputum and serum show promise in the future of lung cancer screening. J. Surg. Oncol. 2003;84:234–238. © 2003 Wiley‐Liss, Inc.
Tumor markers and colorectal cancer: Utility in management
Authors: Crawford Nigel P.S. , Colliver Daniel W. , Galandiuk Susan
Published: December 2003

Colorectal cancer (CRC) is a leading cause of morbidity and mortality. Although genetic testing can screen for rare hereditary CRC syndromes, there is no ideal means of screening for sporadic forms of CRC. This review will focus on markers that are currently used in the management of sporadic CRC and their limitations, as well as possible future clinical applications. J. Surg. Oncol. 2003;84:239–248. © 2003 Wiley‐Liss, Inc.
Similarity between the soil seed bank and the standing vegetation in the Strandveld Succulent Karoo, South Africa
Authors: de Villiers A. J. , Van Rooyen M. W. , Theron G. K.
Published: December 2003

The similarity in species composition and abundance between the soil seed bank and its associated vegetation was studied in six vegetation units of the Strandveld Succulent Karoo, South Africa. A total of 103 taxa were recorded in the vegetation, of which 34 taxa were also present in the seed bank. Five taxa were unique to the soil seed bank. In general, the taxa most abundant in the vegetation were also recorded in the seed bank and vice versa. Mean seed bank density varied between different plant types. Perennial taxa were most abundant in the vegetation, while annual taxa were most abundant in the seed bank. Annual taxa (excluding grasses) yielded the highest similarity between vegetation and seed bank (67ċ9 per cent), while that of perennial (excluding grasses) and grass taxa were 34ċ2 per cent and 40ċ0 per cent respectively. An overall similarity of 47ċ0 per cent between the seed bank and its associated vegetation was obtained for this part of the Strandveld Succulent Karoo. The seed bank of the study site will be a good source of future annual vegetation, but not of perennial vegetation. Topsoil replacement, sowing and transplanting of selected species will be essential for the success of post‐mining revegetation efforts following complete destruction of the existing vegetation. Annual species may be recruited from the soil stored seed bank, while many perennial species will have to be reintroduced by means of sowing and/or transplanting. Copyright © 2003 John Wiley & Sons, Ltd.
Tensile Properties of Extruded Zein Sheets and Extrusion Blown Films
Authors: Wang Ying , Padua Graciela W.
Published: December 2003

Zein‐based plastic sheets and films were formed by extrusion through a slit‐die or blowing head. Zein was plasticized with oleic acid and formed into a wet moldable mass (resin) to feed the extruders. Both single‐ and twin‐screw extruded sheets showed higher elongation at break, lower tensile strength, and lower Young's Modulus than non‐extruded samples. Stress‐strain plots for extruded samples showed evidence of plastic behavior. Observed necking of samples under tensile stress was also taken as evidence of plastic behavior. Small differences in tensile strength and elongation at break between single‐ and twin‐screw extruded samples were attributed to the effect of small voids observed by SEM in single‐screw extruded samples. Blown film extrusion was affected by feed moisture content and barrel temperatures. Optimal moisture content was determined at 14–15% while temperature at the three extruder zones was maintained at 20–25, 20–25, and 35 °C, respectively. Temperature at the blowing head was 45 °C. Film samples blown after either single‐ or twin‐screw extrusion showed similar tensile properties to those of slit die extruded samples.

Blown extrusion of zein film with single‐screw extruder.

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Blown extrusion of zein film with single‐screw extruder.
Transcrystallinity in Surface Modified Aramid Fiber Reinforced Nylon 66 Composites
Authors: Feldman Alexander , Gonzalez M. Fernanda , Marom Gad
Published: December 2003

Aramid (kevlar‐49) fibers were surface treated by two different methods to induce roughness and then used to produce unidirectional nylon 66 based composites. The transcrystallinity generated around the treated fibers was characterized by SEM and polarized light microscopy and compared with the regular transcrystalline layers produced by pristine aramid under the same processing conditions. The treated fibers generated a double transcrystalline layer, the inner layer being thinner and more compact than the regular nylon 66 transcrystallinity. In addition, mechanical testing of the composites showed the longitudinal Young's modulus of the treated fiber composites to be significantly higher than the control in a wide range of fiber volume fractions.

Polarized light microscopy picture of double transcrystallinity in Br/NH3 treated aramid fiber reinforced nylon 66.

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Polarized light microscopy picture of double transcrystallinity in Br/NH3 treated aramid fiber reinforced nylon 66.
Exploring the antecedents and consumer behavior consequences of the trait of superstition
Authors: Mowen John C. , Carlson Brad
Published: December 2003

In two exploratory studies, a hierarchical model of personality was employed to investigate a number of possible trait antecedents and consumer‐behavior–related consequences of superstition. One of the interesting findings was that the antecedents of superstition include a lower need for learning among older adults, higher levels of sports interest, a belief in fate, and a decreased belief in heaven and hell. In addition, the results suggested that the consequences of superstition might include beliefs in astrology, magic, psychokinesis, and the existence of fictitious creatures (e.g., the Loch Ness monster). Evidence suggesting a negative association between superstitious beliefs and attitudes concerning the genetic engineering of food products was also obtained. © 2003 Wiley Periodicals, Inc.
Consumer adoption of the Internet: The case of apparel shopping
Authors: Yoh Eunah , Damhorst Mary Lynn , Sapp Stephen , Laczniak Russ
Published: December 2003

The theory of reasoned action and components of a theory of innovation adoption were integrated into a model of consumer adoption of the Internet for apparel shopping. The hypothesized model included psychological factors (beliefs and attitude), social factors (social support and social acceptance), and prior experience to explain intention to purchase apparel via the Internet. A questionnaire was mailed to a random national sample of households. All hypothesized variables were significant. Prior experience with the Internet had the strongest influence on intention to purchase apparel through the Internet. © 2003 Wiley Periodicals, Inc.
A random evolution related to a Fisher–Wright–Moran model with mutation, recombination and drift
Authors: Bobrowski Adam , Kimmel Marek
Published: December 2003

The paper deals with a model of the genetic process of recombination, one of the basis mechanisms of generating genetic variability. Mathematically, the model can be represented by the so‐called random evolution of Griego and Hersch, in which a random switching process selects from among several possible modes of operation of a dynamical system. The model, introduced by Polanska and Kimmel, involves mutations in the form of a time‐continuous Markov chain and genetic drift. We demonstrate asymptotic properties of the model under different demographic scenarios for the population in which the process evolves. Copyright © 2003 John Wiley & Sons, Ltd.
Toxicogenomic difference between diethylstilbestrol and 17β‐estradiol in mouse testicular gene expression by neonatal exposure
Authors: Adachi Tetsuya , Koh Kyu‐Bom , Tainaka Hitoshi , Matsuno Yoshiharu , Ono Yushin , Sakurai Kenichi , Fukata Hideki , Iguchi Taisen , Komiyama Masatoshi , Mori Chisato
Published: December 2003

In this study, we investigated the effects of neonatal exposure to exogenous estrogen (diethylstilbestrol: DES, 17β‐estradiol: E2) on testicular gene expressions. Male C57BL/6J mice, 1 day after birth, were subcutaneously injected with DES or E2 (3 μg/mouse/day) for 5 days, and then they were raised for 8 weeks. In morphological observation of 8‐week‐old mice testes, spermatozoa were absent from many seminiferous tubules in DES‐treated mice testes, but there was no change in E2‐treated mice testes. Analysis of in‐house cDNA microarray (mouse cDNA 889 genes) revealed that 17 genes were altered in DES‐treated mice testes at 8 weeks of age, compared to each control. Real‐time reverse transcription‐polymerase chain reaction (real‐time RT‐PCR) analysis of these genes revealed that some genes, which were changed in E2‐treated testis, were the same as in DES‐treated testis, whereas in other cases there was a difference between DES‐treated and E2‐treated testis. The present results suggest that each exogenous estrogenic compound has both a common gene expression change pattern and its own testicular gene expression change pattern. Mol. Reprod. Dev. 67: 19–25, 2004. © 2004 Wiley‐Liss, Inc.
Cryopreservation of Xenopus transgenic lines
Authors: Buchholz Daniel R. , Fu Liezhen , Shi Yun‐Bo
Published: December 2003

Xenopus laevis has been widely used for molecular, cellular, and developmental studies. With the development of the sperm‐mediated transgenic method, it is now possible to study gene function during vertebrate development by using this popular model. On the other hand, like other animal species, it is labor intensive, and the maintenance of transgenic lines is expensive. In this article, we investigated the possibility of using sperm‐cryopreservation as a means to preserve transgenic frog lines. We demonstrated that cryopreserved sperms are viable but not fertile under our in vitro fertilization (IVF) conditions. However, by microinjecting cryopreserved sperm nuclei, we successfully regenerated a transgenic line carrying a double promoter transgene construct, where the marker gene encoding the green fluorescent protein (GFP) is driven by the γ‐crystallin gene promoter and a gene of interest, encoding a fusion protein of GFP with the matrix metalloproteinase stromelysin‐3 (ST3‐GFP), is driven by a heat shock‐inducible promoter. We demonstrated the functional transmission of the ST3‐GFP transgene by analyzing the phenotype of the F1 animals after heat‐shock to induce its expression. Our method thus provides an inexpensive means to preserve transgenic frog lines and a convenient way for distribution of transgenic lines. Furthermore, the ease with which to microinject nuclei compared to the technically demanding transgenesis procedure with variable outcome should facilitate more laboratories to use transgenic Xenopus laevis for functional studies in vivo. Mol. Reprod. Dev. 67: 65–69, 2004. © 2004 Wiley‐Liss, Inc.
Comparison of bulk enucleation methods for porcine oocytes
Authors: Savard Christian , Novak Susan , Saint‐Cyr Antoine , Moreau Marc , Pothier Francois , Sirard Marc‐André
Published: December 2003

Cloning of mammalian oocytes requires that the recipient oocyte is enucleated to remove all genetic material associated with the chromosomes. The procedure currently used in most species requires careful micromanipulation of oocytes treated with cytochalasin B to prevent structural damage. Although functional, this procedure requires time and limits the number of oocytes available for cloning, and our ability to understand the mechanisms of nuclear reprogramming. Therefore, this study aimed at evaluating different procedures to enucleate large pools of oocytes in a time‐efficient manner. Two different approaches were tested. The first approach involved centrifugation of zona‐free oocytes through a percoll gradient to separate the portion containing the chromatin from the cytoplasmic portion. The second used etoposide to prevent chromatin segregation at first metaphase and resulting in the expulsion of all chromosomes in the polar body. Using the chemical approach an average enucleation rate of 39.4 ± 7.5% was obtained, while the centrifugation approach resulted in an average enucleation rate of 66.9 ± 6. In terms of time efficiency, the control manipulation method takes 0.11 min and the centrifugation took an average of 0.52 min per oocyte. The MPF activity at the end of procedure was estimated through the measurement of H1 activity and as expected, the etoposide‐cycloheximide treated oocytes had lower H1 activity which was restored by further incubation in the maturation medium for 5 hr while the centrifugation gave a nonsignificant intermediary result. In conclusion, the results presented suggest that both the chemical and the mechanical methods are usable alternatives to micromanipulation of oocytes to generate a large number of chromosome free cytoplasm for biochemical analysis. Mol. Reprod. Dev. 67: 70–76, 2004. © 2004 Wiley‐Liss, Inc.
Sexing river buffalo (Bubalus bubalis L.), sheep (Ovis aries L.), goat (Capra hircus L.), and cattle spermatozoa by double color FISH using bovine (Bos taurus L.) X‐ and Y‐painting probes
Authors: Di Berardino Dino , Vozdova Miluse , Kubickova Svatava , Cernohorska Halina , Coppola Giuseppe , Coppola Gianfranco , Enne Giuseppe , Rubes Jiri
Published: December 2003

River buffalo, sheep, and goat spermatozoa were cross‐hybridized using double color fluorescence in situ hybridization (FISH) with bovine Xcen‐ and Y‐chromosome painting probes, prepared by DOP‐PCR of laser‐microdissected‐catapulted chromosomes, to investigate the possibility of using bovine probes for sexing sperm of other members of the family Bovidae. Before sperm analysis, the probes were hybridized on metaphase chromosomes of each species, as control. Frozen‐thawed spermatozoa of cattle, river buffalo, sheep, and goat were decondensed in suspension with 5 mM DTT. Sperm samples obtained from three individuals of each species were investigated, more than 1,000 spermatozoa were scored in each animal. FISH analysis of more than 12,000 sperm revealed high level of sperm with X‐ or Y‐signals in all of the species investigated, indicating FISH efficiency over 99%. Significant interspecific differences were detected in the frequency of aberrant spermatozoa (aneuploid and diploid) between goat (0.393%) and sheep (0.033%) (P < 0.01), goat and cattle (0.096%) (P < 0.5), as well as between river buffalo (0.224%) and sheep (P < 0.5). There was no significant difference between river buffalo and cattle. The present study demonstrated that it is possible to use bovine X‐Y painting probes for sexing and analyzing sperm of other species of the family, thus facilitating future studies on the incidence of chromosome abnormalities in sperm as well as on sex predetermination of embryos for the livestock industry. Mol. Reprod. Dev. 67: 108–115, 2004. © 2004 Wiley‐Liss, Inc.
Diagnostic testing for hearing loss in infants and young children
Authors: Widen Judith E. , Keener Sandra K.
Published: December 2003

An early, reliable diagnosis and description of hearing loss is essential in determining appropriate treatment to minimize potential developmental delays attributed to the loss. Objective assessment of auditory function is possible shortly after birth. Both objective and subjective measures of auditory status are used in a test battery approach to determine the type, degree, and configuration of the hearing loss. This paper reviews the diagnostic test procedures used to define the hearing capability of infants and young children. For the youngest infants electrophysiologic tests, primarily auditory evoked potentials, are used to estimate hearing sensitivity. Later behavioral audiometric measures based on operant conditioning techniques become the primary component of the test battery. Diagnostic audiologic assessment is an ongoing process that requires special equipment and expertise when directed to infants and young children. MRDD Research Reviews 2003;9:220–224. © 2003 Wiley‐Liss, Inc.
Communication options for children with hearing loss
Authors: Gravel Judith S. , O'Gara Jessica
Published: December 2003

This article examines the communication options that are available for use within families of infants and young children who are hard‐of‐hearing or deaf. The need for language development, regardless of the specific communication mode, is stressed. The demands of the current environment of early identification and intervention often put families in a position of needing to decide among communication methods before they are fully knowledgeable and/or emotionally ready. Specific communication options are delineated and considered within a continuum of spoken and visual language. Available research related to early acquisition of language by infants and young children who are hard‐of‐hearing and deaf is reviewed; outcomes, when available, are presented for specific methods from reports of older children. Factors that influence families' decisions regarding the selection of a communication option are highlighted in the context of the existing literature. An ongoing evaluative process that respects the choices of families is advocated; a context in which change(s) in communication mode through childhood is viewed as a positive circumstance. The ultimate goal in the selection of any communication approach is to ensure that infants and young children who are hard of hearing or deaf and their families are language proficient and fluent communicators. MRDD Research Reviews 2003;9:243–251. © 2003 Wiley‐Liss, Inc.
Automated segmentation and analysis of vascular structures in magnetic resonance angiographic images
Authors: de Koning P.J.H. , Schaap J.A. , Janssen J.P. , Westenberg J.J.M. , van der Geest R.J. , Reiber J.H.C.
Published: December 2003

The accurate assessment of the presence and extent of vascular disease, and planning of vascular interventions based on MRA requires the determination of vessel dimensions. The current standard is based on measuring vessel diameters on maximum intensity projections (MIPs) using calipers. In order to increase the accuracy and reproducibility of the method, automated analysis of the 3D MR data is required. A novel method for automatically determining the trajectory of the vessel of interest, the luminal boundaries, and subsequent the vessel dimensions is presented. The automated segmentation in 3D uses deformable models, combined with knowledge of the acquisition protocol. The trajectory determination was tested on 20 in vivo studies of the abdomen and legs. In 93% the detected trajectory followed the vessel. The luminal boundary detection was validated on contrast‐enhanced (CE) MRA images of five stenotic phantoms. The results from the automated analysis correlated very well with the true diameters of the phantoms used in the in vitro study (r = 0.999, P < 0.001). MRA and x‐ray angiography (XA) of the phantoms also correlated well (r = 0.895, P < 0.001). The average unsigned difference between the MRA and XA measurements was 0.08 ± 0.05 mm. In conclusion, the automated approach allows the accurate assessment of vessel dimensions in MRA images. Magn Reson Med 50:1189–1198, 2003. © 2003 Wiley‐Liss, Inc.
Out‐and‐in spiral spectroscopic imaging in rat brain at 7 T
Authors: Hiba Bassem , Faure Bérengère , Lamalle Laurent , Décorps Michel , Ziegler Anne
Published: December 2003

With standard spectroscopic imaging, high spatial resolution is achieved at the price of a large number of phase‐encoding steps, leading to long acquisition times. Fast spatial encoding methods reduce the minimum total acquisition time. In this article, a k‐space scanning scheme using a continuous series of growing and shrinking, or “out‐and‐in,” spiral trajectories is implemented and the feasibility of spiral spectroscopic imaging for animal models at high B0 field is demonstrated. This method was applied to rat brain at 7 T. With a voxel size of about 8.7 μl (as calculated from the point‐spread function), a 30 × 30 matrix, and a spectral bandwidth of 11 kHz, the minimum scan time was 9 min 20 sec for a signal‐to‐noise ratio of 7.1 measured on the N‐acetylaspartate peak. Magn Reson Med 50:1127–1133, 2003. © 2003 Wiley‐Liss, Inc.
Contribution of mitochondria to cardiac muscle water/macromolecule proton magnetization transfer
Authors: Ward Kathleen , Schussheim Adam E. , Balaban Robert S.
Published: December 2003

The contribution of mitochondria to water‐macromolecule proton magnetization transfer (MT) was evaluated in porcine heart tissue. An examination of isolated mitochondria in suspension, at the same concentration as found in heart tissue, revealed MT effects very similar in magnitude and bandwidth to those in intact heart tissue. Disruption of the gross structure of the mitochondria by freeze‐thawing or with detergent resulted in only ∼25% decreases in MT, which suggests that the structure of the mitochondria is not critical for these effects. The current data indicate that mitochondria macromolecules contribute significantly to MT in the intact heart. Magn Reson Med 50:1312–1316, 2003. Published 2003 Wiley‐Liss, Inc.
Optimized detection of changes in glucose‐6‐phosphate levels in human skeletal muscle by 31P MR spectroscopy
Authors: de Haan Jacco H. , Klomp D.W.J. , Tack C.J. , Heerschap A.
Published: December 2003

As glucose‐6‐phosphate (G6P) plays a central role in muscle energy metabolism, the possibility to observe changes in the tissue level of this compound in vivo is very relevant. G6P can be detected noninvasively by 31P MR spectroscopy, but its visibility in vivo is severely hampered due to low tissue levels and spectral overlap with other, stronger phosphomonoester signals. To optimize the observation of changes in G6P levels in human calf muscle by 31P MR spectroscopy at 1.5 T, we implemented an approach involving a new RF probe and a postacquisition correction method. An anatomically shaped circularly polarized 31P coil was designed for high intrinsic sensitivity. Together with an additional 1H coil and 1H blocking circuits this allowed the application of NOE and 1H decoupling to further enhance sensitivity. A hyperglycemic hyperinsulinemic clamp was used to increase G6P levels. The spectra were corrected for frequency and phase drift due to scanner instability and leg movements using an automated phase and frequency correction method. Difference 31P spectroscopy was applied to detect changes of the G6P signal. The result, in five healthy subjects, demonstrated that the combination of sensitivity optimization with automated drift correction enabled a robust detection of G6P changes in time series experiments down to a resolution of 10 min. Magn Reson Med 50:1302–1306, 2003. © 2003 Wiley‐Liss, Inc.
Influence of magnetically‐induced E‐fields on cardiac electric activity during MRI: A modeling study
Authors: Liu Feng , Xia Ling , Crozier Stuart
Published: December 2003

In modern magnetic resonance imaging (MRI), patients are exposed to strong, time‐varying gradient magnetic fields that may be able to induce electric fields (E‐fields)/currents in tissues approaching the level of physiological significance. In this work we present theoretical investigations into induced E‐fields in the thorax, and evaluate their potential influence on cardiac electric activity under the assumption that the sites of maximum E‐field correspond to the myocardial stimulation threshold (an abnormal circumstance). Whole‐body cylindrical and planar gradient coils were included in the model. The calculations of the induced fields are based on an efficient, quasi‐static, finite‐difference scheme and an anatomically realistic, whole‐body model. The potential for cardiac stimulation was evaluated using an electrical model of the heart. Twelve‐lead electrocardiogram (ECG) signals were simulated and inspected for arrhythmias caused by the applied fields for both healthy and diseased hearts. The simulations show that the shape of the thorax and the conductive paths significantly influence induced E‐fields. In healthy patients, these fields are not sufficient to elicit serious arrhythmias with the use of contemporary gradient sets. However, raising the strength and number of repeated switching episodes of gradients, as is certainly possible in local chest gradient sets, could expose patients to increased risk. For patients with cardiac disease, the risk factors are elevated. By the use of this model, the sensitivity of cardiac pathologies, such as abnormal conductive pathways, to the induced fields generated by an MRI sequence can be investigated. Magn Reson Med 50:1180–1188, 2003. © 2003 Wiley‐Liss, Inc.
Quantification of bolus‐tracking MRI: Improved characterization of the tissue residue function using Tikhonov regularization
Authors: Calamante Fernando , Gadian David G. , Connelly Alan
Published: December 2003

Quantification of cerebral blood flow (CBF) and the tissue residue function (R) using bolus‐tracking MRI requires deconvolution of the arterial input function (AIF). Currently, the most commonly used deconvolution method is singular value decomposition (SVD), which has been shown to produce accurate estimations of CBF. However, this method introduces unwanted oscillations in the time course of R, and there are situations in which the actual shape is of interest (e.g., in calculating flow heterogeneity and assessing bolus dispersion). In such cases, the conventional SVD method may no longer be suitable, and an alternative approach may be required. This work describes the implementation of Tikhonov regularization with the L‐curve criterion to quantify CBF and obtain a better characterization of R. The methodology is tested on simulated and patient data, and the results are compared to those found using the conventional SVD approach. Although both methods produce similar CBF values, the deconvolved R shape obtained using SVD is dominated by oscillations and fails to characterize the shape in the presence of dispersion. On the other hand, the use of the proposed regularization method improves the characterization of the tissue residue function. Magn Reson Med 50:1237–1247, 2003. © 2003 Wiley‐Liss, Inc.
Fast 3D imaging using variable‐density spiral trajectories with applications to limb perfusion
Authors: Lee Jin Hyung , Hargreaves Brian A. , Hu Bob S. , Nishimura Dwight G.
Published: December 2003

Variable‐density k‐space sampling using a stack‐of‐spirals trajectory is proposed for ultra fast 3D imaging. Since most of the energy of an image is concentrated near the k‐space origin, a variable‐density k‐space sampling method can be used to reduce the sampling density in the outer portion of k‐space. This significantly reduces scan time while introducing only minor aliasing artifacts from the low‐energy, high‐spatial‐frequency components. A stack‐of‐spirals trajectory allows control over the density variations in both the kx–ky plane and the kz direction while fast k‐space coverage is provided by spiral trajectories in the kx–ky plane. A variable‐density stack‐of‐spirals trajectory consists of variable‐density spirals in each kx–ky plane that are located in varying density in the kz direction. Phantom experiments demonstrate that reasonable image quality is preserved with approximately half the scan time. This technique was then applied to first‐pass perfusion imaging of the lower extremities which demands very rapid volume coverage. Using a variable‐density stack‐of‐spirals trajectory, 3D images were acquired at a temporal resolution of 2.8 sec over a large volume with a 2.5 × 2.5 × 8 mm3 spatial resolution. These images were used to resolve the time‐course of muscle intensity following contrast injection. Magn Reson Med 50:1276–1285, 2003. © 2003 Wiley‐Liss, Inc.
Multishot partial‐k‐space EPI for high‐resolution fMRI demonstrated in a rat whisker barrel stimulation model at 3t
Authors: Lu Hanbing , Mazaheri Yousef , Zhang Rongyan , Jesmanowicz Andrzej , Hyde James S.
Published: December 2003

A multishot partial‐k‐space EPI technique is presented and validated by fMRI at high spatial resolution. High‐resolution phase maps corrected by phase‐encoded reference scans have less off‐resonance effects. Phantom studies demonstrate that this method can substantially improve partial‐k‐space EPI image formation. BOLD fMRI at submillimeter spatial resolution (156 × 156 × 2000 μm3, 0.049 μl) was achieved in a rat whisker barrel stimulation model using this technique. The study included eight rats, five of which were administered an intravascular contrast agent (monocrystalline iron oxide nanocolloid (MION)) after the BOLD experiments. In two rats the highest BOLD responses were in the deep layers (IV–VI), and in six rats the highest responses were on the surface and in the deep cortical layers. Most of the pixels that exhibited high BOLD responses had high blood volume weightings. The benefits of this technique are expected to increase for high‐resolution fMRI at higher magnetic fields, where T is shorter. Magn Reson Med 50:1215–1222, 2003. © 2003 Wiley‐Liss, Inc.
Erratum
Authors: Utting Jane F. , Thomas David L. , Ordidge Roger J. , Gadian David G.
Published: December 2003

The original article to which this Erratum refers was published in Magnetic Resonance in Medicine (2003) 49(2) 398–401.
The second order characteristic condition for plastic flow
Authors: Weir Graham , Young Roger
Published: December 2003

In this paper the second order characteristic (discontinuous bifurcation) condition is derived for the granular flow (fully plastic) equations. This second order bifurcation equation is shown to be formally identical to the first order localization requirement during steady elastoplastic deformation provided the elastic compliance tensor is substituted for the product of the plastic multiplier with the flow Hessian. For isotropic yield and flow functions the invariant form of the characteristic condition is given in detail, as well as an alternative expression in adapted co‐ordinates. The characteristic condition can be regarded as defining a hardening function which is maximized to identify the critical angles. When the method is applied to 3D Coulomb flow, Mohr's 3D fracture plane conditions are obtained uniquely. Copyright © 2003 John Wiley & Sons, Ltd.
Baseline physiological state and the fMRI‐BOLD signal response to apnea in anesthetized rats
Authors: Kannurpatti Sridhar S. , Biswal Bharat B. , Hudetz A. G.
Published: December 2003

To decipher the biophysical mechanism behind the fMRI‐BOLD response to apnea and its dependence on the baseline cerebral blood flow and oxygenation, fMRI and laser Doppler flow (LDF) studies were carried out in anesthetized rats. Baseline cerebral blood flow (CBF) and PaO2 were modulated by ventilating with different gas mixtures namely, room air (21% O2), 100% O2, carbogen (95% O2+5% CO2), 2% CO2 in air or 5% CO2 in air, respectively. A decrease in BOLD signal intensity was observed after the onset of apnea with either room air, 2% CO2 or 5% CO2 ventilation. PaO2 and cerebral tissue PO2 decreased during apnea under these conditions. However, the apnea‐induced BOLD signal intensity was unaffected with carbogen ventilation and increased with 100% O2 ventilation, during which PaO2 remained constant and cerebral tissue PO2 increased. When baseline CBF was high during hypercapnia, a faster decrease occurred in the apnea‐induced BOLD signal. Apnea induced the largest increase in CBF of 85±25% when ventilated with 2% CO2 while a 44±8% increase was observed with room air. During the other ventilatory conditions, minimal or no significant change in CBF was observed during apnea. These results show a significant correlation between the BOLD signal change and tissue PO2 in response to apnea under different physiological conditions. Apnea‐induced increase in CBF affects the magnitude of the BOLD signal response when PaO2 remains constant or changes minimally. Copyright © 2001 John Wiley & Sons, Ltd.
Absolute eigenvalue diffusion tensor analysis for human brain maturation
Authors: Suzuki Yuji , Matsuzawa Hitoshi , Kwee Ingrid L. , Nakada Tsutomu
Published: December 2003

The absolute eigenvalues of the diffusion tensor of white matter in sixteen normal subjects in two groups representing the early developmental stage (ages 1–10 years, n = 8) and young adult stage (ages 18–34 years, n = 8) were assessed using a high‐field (3.0 T) magnetic resonance (MR) system. All three eigenvalues, including the largest eigenvalue, decreased significantly with brain maturation. The rate of the decline in the two small eigenvalues was, however, much higher than that of the largest eigenvalue, resulting in an actual increase in fractional anisotropy, a commonly measured relative index. The data demonstrate that an increase in anisotropy associated with brain maturation represents a significant decline in the small eigenvalue components, rather than an increase in the largest eigenvalue. The observed pattern of eigenvalue changes is best explained by the simultaneous occurrence of two of several independent phenomena within the axonal microenvironment during the myelination process, namely, (1) decline in unrestricted water content in extra‐axonal space, and (2) increase in apparent diffusivity within the axon. Copyright © 2003 John Wiley & Sons, Ltd.
The influence of management on the cost of fire protection
Authors: Donahue Amy K.
Published: December 2003

An important and unresolved issue central to the study of government performance is how the actions of managers
and the nature of organizations affect the cost of public services. This paper presents an empirical analysis of
fire departments that estimates the influence of managerial choices on per capita spending within a simultaneous
public production system. It does so by refining a theoretical cost model from the field of public management to
include fundamental dimensions of government organizations and administration. Two‐stage least squares
regression analysis is then employed to examine the fire protection case. The results of the analysis substantiate
the intuition that managerial practices and decisions influence the cost of a public service. They show that the
cost of fire protection depends significantly on the outcomes of a department's fire prevention and suppression
activities, some key aspects of a department's management practices, the configuration of its workforce and
equipment, its legal structure, and factors in its external environment. © 2004 by the Association for Public
Policy Analysis and Management.
Erratum: Integrins in regulation of tissue development and function. J Pathol; 200: 471–480
Authors: Danen Erik HJ , Sonnenberg Arnoud
Published: December 2003

The original article to which this Erratum refers was published in Journal of Pathology; 200(4): 471–480.

It has been brought to the attention of the publishers that there were errors on pages 476, 477 and 480 of the orginally published manuscript. These errors have now been rectified, and to facilitate greater legibility for our readers, the corrected article has been reproduced in its entirety.

Cell adhesion is indispensable for embryonic development and for proper tissue function. In metazoans, integrins are the major adhesion receptors that connect cells to components of the extracellular matrix. Integrins are implicated in assembly of extracellular matrices, cell adhesion and migration on extracellular matrices, and in vertebrates (in which the integrin family has expanded) they can also mediate cell–cell adhesion. Furthermore, integrin‐mediated adhesion can modulate many different signal transduction cascades and support cell survival, proliferation, and influence the expression of differentiation‐related genes. In this review we briefly explain how integrins can affect so many different aspects of cell behavior and discuss evidence for roles of integrins in tissue development, function, and disease. Copyright © 2003 John Wiley & Sons, Ltd.
A prospective study of thyroid nodular disease in children and adolescents in western Poland from 1996 to 2000 and the incidence of thyroid carcinoma relative to iodine deficiency and the Chernobyl disaster
Authors: Niedziela Marek , Korman Eugeniusz , Breborowicz Danuta , Trejster Ewa , Harasymczuk Jerzy , Warzywoda Malgorzata , Rolski Michal , Breborowicz Jan
Published: December 2003

Background

In Poland, where soil is deficient in iodine, supplementation of iodine was introduced in 1935, discontinued in 1980, and then re‐introduced in 1997. One of the effects of inadequate iodine intake, prior to 1997, was an increase in the prevalence of thyroid nodular disease (TND) in children. Chernobyl, located in the neighbouring country of Ukraine, suffered a catastrophic nuclear explosion in April 1986.

Procedure

A total of 411 children with TND (an incidence of 7.53/100,000) were diagnosed and registered in western Poland between 1996 and 2000 and further evaluated as a population‐based study.

Results

Based on the patient's clinical status, ultrasound examination, scintiscan, laboratory tests, cytology and the family history, many of the patients qualified for surgery and, as a result, histopathologic data were obtained from 155 of the 411 patients operated on to date (37.7% of all TND). Thyroid carcinoma was detected in 37 of the operated children, i.e. 23.9% or 9.0% of all children with TND with a median incidence of 0.68/100,000. Papillary carcinoma was the predominant histologic type (26–70.3%) compared to follicular carcinoma (10–27.0%) and medullary carcinoma (1–2.7%). Retrospective analysis of the figures for the 23 years (1972–1995) showed that in that period a total of 23 thyroid carcinomas were registered. However, only 12 of these were detected in the 20‐year period between 1972 and 1991, none in the years 1992–1993 and, significantly, 11 from 1994 to 1995.

Conclusions

Thyroid carcinoma appears to be an ongoing and increasing problem in the children and adolescents of our region, and it is developing more intensively when compared, both to other parts of Poland and to previous statistics (2000 vs. 1985; P < 0.002). Iodine deficiency and radiation resulting from the Chernobyl disaster might be important risk factors in the development of thyroid carcinoma in the young population analysed in our region in the period since 1994. The high percentage of follicular carcinoma and follicular adenoma with an undetermined prognosis (19 out of 46) indicates that the long‐term iodine deficiency in our region may be more significant in the pathogenesis of malignant transformation than has previously been postulated. Pediatr Blood Cancer 2004;42:84–92. © 2003 Wiley‐Liss, Inc.
Immune responses to influenza immunization in children receiving maintenance chemotherapy for acute lymphoblastic leukemia
Authors: Porter Christopher C. , Edwards Kathryn M. , Zhu Yuwei , Frangoul Haydar
Published: December 2003

Purpose

To compare the immune responses to influenza vaccine in children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy with those in healthy children.

Methods

Hemagglutinin‐inhibition (HAI) antibody titers were determined before and after influenza vaccination in children with ALL and healthy controls. Immune responses were measured as geometric mean titers (GMT) and 4‐fold rises in HAI titers.

Results

Although post‐immunization GMT were lower in children with ALL compared to healthy children for the H1N1 antigen (P < 0.001), the H3N2 antigen (P = 0.03), and for the influenza B antigen (P = 0.003), at least 60% of children with ALL had at least a 4‐fold rise in HAI titers to each of the influenza antigens.

Conclusions

While the GMT after trivalent influenza immunization in children with ALL were significantly lower than those seen in healthy children, the majority of children with ALL had 4‐fold rises in HAI titers. Children receiving maintenance chemotherapy for ALL should receive yearly influenza vaccine. © 2003 Wiley‐Liss, Inc.