bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of natural antibody specificity on antigen immunogenicity
Authors: Benatuil Lorenzo , Kaye Joel , Rich Robert F. , Fishman Jay A. , Green William R. , Iacomini John 
Published: August 2005

AbstractThe natural antibody repertoire in humans, apes and Old World primates is distinct from the repertoire of all other placental mammals, and encodes antibodies specific for the carbohydrate epitope Galα1–3Galβ1–4GlcNAc‐R (αGal). Here, we examined whether conjugating antigens to the αGal epitope can augment their immunogenicity in α(1,3)galactosyltransferase knockout mice (GT0 mice) which, like humans, produce αGal‐specific antibodies. Immunization of GT0 mice with BSA conjugated to αGal (αGal‐BSA) led to significant production of anti‐BSA IgG antibodies without the need for adjuvant. This response was dependent on the presence of αGal‐reactive antibodies. Immunization of wild‐type mice with αGal‐BSA failed to induce an anti‐BSA response. The presence of αGal‐reactive antibodies also led to an increase in the T cell response to BSA following immunization with αGal‐BSA when compared with mice that received BSA alone, resulting in an increased frequency of IFN‐γ− and IL‐4‐producing BSA‐specific T cells. In addition, the ability to produce αGal‐reactive antibodies enhanced the cytotoxic T lymphocyte anti‐viral antigen response following vaccination with murine leukemia virus transformed cell lines that express αGal on their cell surface. Natural antibodies that bind αGal therefore play a key role in increasing the efficiency of priming to antigens decorated with αGal epitopes.
Early regulation of CD8 T cell alloreactivity by CD4+CD25– T cells in recipients of anti‐CD154 antibody and allogeneic BMT is followed by rapid peripheral deletion of donor‐reactive CD8+ T cells, precluding a role for sustained regulation
Authors: Fehr Thomas , Takeuchi Yasuo , Kurtz Josef , Wekerle Thomas , Sykes Megan 
Published: August 2005

AbstractWhile acquisition of regulatory function by CD4+CD25– T cells has been reported following antigenic stimulation, “naturally occurring” regulatory CD4+ T cells (Treg) are believed to express CD25. We examined the mechanisms involved in peripheral CD8 T cell tolerance by induction of mixed chimerism using non‐myeloablative conditioning with low‐dose (3 Gy) total body irradiation and anti‐CD154 antibody. Recipient CD4+ T cells were initially required for the induction of CD8 cell tolerance, but were not needed beyond 2 weeks. Depletion of CD25+ Treg prior to bone marrow transplantation and blockade of IL‐2 with neutralizing antibody did not impede tolerance induction. Tolerance was dependent on CTLA4, but not on IFN‐γ. In C57BL/6 mice containing a fraction of 2C TCR transgenic CD8+ T cells, which recognize the MHC class I alloantigen Ld, induction of chimerism with Ld+, but not Ld–, bone marrow cells led to deletion of peripheral 2C+ CD8+ cells within 1 week in peripheral blood and spleen. Complete deletion required the presence of recipient CD4+ T cells. Thus, a novel, rapid form of regulation by CD4+CD25– T cells permits initial CD8 T cell tolerance in this model. Rapid peripheral deletion of donor‐specific CD8 T cells precludes an ongoing requirement for CD4 T cell‐mediated regulation.
Carbohydrates located on the top of the “cap” contribute to the adhesive and enzymatic functions of vascular adhesion protein‐1
Authors: Maula Sanna‐Mari , Salminen Tiina , Kaitaniemi Sam , Nymalm Yvonne , Smith David J. , Jalkanen Sirpa 
Published: August 2005

AbstractVascular adhesion protein 1 (VAP‐1) is an endothelial adhesion molecule with an enzymatic activity. It deaminates biogenic amines, resulting in the formation of aldehydes and hydrogen peroxide. During the enzymatic reaction a transient Schiff base is formed between endothelial VAP‐1 and its leukocytic ligand, and this interaction is important for lymphocyte adhesion. VAP‐1 monomer has six potential N‐linked, and three putative O‐linked glycosylation sites and an SSSS sequence potentially forming an attachment site for an adjacent O‐linked site. In this work we modeled the carbohydrate decorations on a structural model of VAP‐1, and studied which of those potential glycosylation sites are utilized, and whether those decorations accessible to a lymphocyte ligand are important in lymphocyte adhesion and enzymatic activity of VAP‐1. We show that, unlike the O‐linked attachment sites, all six N‐linked glycosylation sites are in use. Furthermore, mutation of the N‐linked attachment sites strategically located on the top of the molecule reduces lymphocyte adhesion in non‐static conditions, and enhances the catalytic activity of membrane‐bound human VAP‐1 in static conditions, suggesting that glycosylation regulates the functional properties of VAP‐1.
Surface modification of gold and quantum dot nanoparticles with chitosan for bioapplications
Authors: Tan Wee Beng , Zhang Yong 
Published: August 2005

AbstractGold (Au) and quantum dot (QD) nanoparticles, which have been extensively used in many fields, were encapsulated with a natural polymer, chitosan, to improve their biocompatibility. Characterization was performed using ultraviolet–visible, dynamic light scattering, atomic force microscopy, and transmission electron microscope analyses. It was found that a Au/chitosan ratio of 1:1 and smaller produced chitosan‐encapsulated Au nanoparticles of a sufficiently small size, and this result was then applied in the chitosan encapsulation of QDs. The biocompatibility of both types of nanoparticles was assessed in cell culture studies using HT29 human colon carcinoma and NIH 3T3 mouse fibroblast cells. MTT and trypan blue exclusion assays revealed that both chitosan‐encapsulated Au nanoparticles and QDs exhibited improved biocompatibility over their bare, nonencapsulated counterparts. Therefore, this study showed that chitosan could be used to encapsulate both Au nanoparticles and QDs in order to enhance their biocompatibility. The approaches developed in this study can also be extended to other nanoparticles for bioapplications as well. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Edge disjoint cycles through specified vertices
Authors: Goddyn Luis , Stacho Ladislav 
Published: August 2005

AbstractWe give a sufficient condition for a simple graph G to have k pairwise edge‐disjoint cycles, each of which contains a prescribed set W of vertices. The condition is that the induced subgraph G[W] be 2k‐connected, and that for any two vertices at distance two in G[W], at least one of the two has degree at least |V(G)|/2 + 2(k − 1) in G. This is a common generalization of special cases previously obtained by Bollobás/Brightwell (where k = 1) and Li (where W = V(G)). A key lemma is of independent interest. Let G be the complement of a bipartite graph with partite sets X, Y. If G is 2k connected, then G contains k Hamilton cycles that are pairwise edge‐disjoint except for edges in G[Y]. © 2005 Wiley Periodicals, Inc. J Graph Theory
Development and growth of long bones in European water frogs (Amphibia: Anura: Ranidae), with remarks on age determination
Authors: Rozenblut Beata , Ogielska Maria 
Published: August 2005

AbstractDifferentiation and development of long bones were studied in European water frogs: Rana lessonae, R. ridibunda, and R. esculenta. The study included premetamorphic larvae (Gosner Stage 40) to frogs that were 5 years old. Femora, metatarsal bones, and proximal phalanges of the hindlimb exhibit the same pattern of periosteal bone differentiation and the same pattern of growth. Longitudinal and radial growth of these bones was studied by examination of the diaphyses and epiphyses, particularly where the edge of periosteal bone is inserted into the epiphysis. The periosteum seems to be responsible for both longitudinal and radial growth. Investigation of the formation, length, and arrangement of lines of arrested growth reveals that the first line is present only in the middle 25–35% of the length of the diaphysis of an adult bone; therefore, only the central portion of the diaphysis should be used for age estimation in skeletochronological studies. Comparison of the shapes and histological structures of epiphyses in the femur, metatarsal bones, and phalanges revealed that epiphyseal cartilages are composed of an inner and outer part. The inner metaphyseal cartilage has distinct zones and plugs the end of the periosteal bone cylinder; its role in longitudinal growth is questioned. The outer epiphyseal cartilage is composed of articular cartilages proper, in addition to lateral articular cartilages. Differences in the symmetry of the lateral articular cartilages of distal epiphyses of the femur and toes may reflect adaptations to different kinds of movements at the knee and in the foot. J. Morphol. © 2005 Wiley‐Liss, Inc.
Astroglial cells in the central nervous system of the adult brown anole lizard, Anolis sagrei, revealed by intermediate filament immunohistochemistry
Authors: Lazzari Maurizio , Franceschini Valeria 
Published: August 2005

AbstractWe analyzed the distribution of intermediate filament molecular markers, glial fibrillary acidic protein (GFAP), and vimentin in the brain and spinal cord of the adult brown anole lizard, Anolis sagrei. The GFAP immunoreactivity is strong and the positive structures are basically represented by fibers of different lengths and thicknesses which are arranged in a regular radial pattern throughout the central nervous system. In the brain regions that have a thicker neural wall, the radial orientation is not so evident as in the thinner areas. These fibers emerge from radial ependymoglia (tanycytes) whose cell bodies are generally GFAP‐immunopositive. The glial fibers give rise to endfeet that are apposed to the subpial surface and to blood vessel walls. In the spinal cord, the optic tectum and the lateroventral regions of the mesencephalon and medulla oblongata, star‐shaped astrocytes coexist with radial structures. Vimentin‐immunoreactive structures are absent in the brain and spinal cord. In A. sagrei the immunohistochemical response of the astroglial intermediate filaments appears typical of a mature astroglial cell lineage, since they fundamentally express GFAP immunoreactivity. A Western‐blot analysis reveals a GFAP‐positive single band, common to the different nervous areas. This immunohistochemical study shows that the star‐shaped astrocytes have a different distribution in saurians and while the glial pattern of A. sagrei is more evolved than in urodeles it remains immature as compared with crocodilians, avians, and mammals. This condition suggests that reptiles represent a fundamental step in the phylogenetic evolution of the vertebrate glial cells. J. Morphol. © 2005 Wiley‐Liss, Inc.
Stable expression of EBERs in immortalized nasopharyngeal epithelial cells confers resistance to apoptotic stress
Authors: Wong Hing Lok , Wang Xianghong , Chang Raymond Chuen‐Chung , Jin Dong‐Yan , Feng Huichen , Wang Qi , Lo Kwok‐Wai , Huang Dolly P. , Yuen Po Wing , Takada Kenzo , Wong Yong Chuan , Tsao Sai Wah 
Published: August 2005

AbstractEpstein–Barr virus (EBV) infection is closely associated with the development of nasopharyngeal carcinoma (NPC). The EBV‐encoded RNAs (EBERs) are the most abundant EBV transcripts (about 107 copies per cell) in EBV infected cells. However, the cellular function of EBER expression, particularly in nasopharyngeal epithelial cells, remains poorly understood. EBERs acquire secondary structures analogous to double‐stranded RNA (dsRNA) and may bind to the double‐stranded RNA‐dependent protein kinase (PKR) and interfere with its function. Activation of PKR involves autophosphorylation resulting in protein synthesis inhibition and cellular apoptosis. Induction of cellular apoptosis by activation of PKR may be an antiviral response adopted by virally infected cells. We have examined the functional properties of EBER expression in an immortalized nasopharyngeal epithelial cell line (NP69). Expression of EBERs was achieved by transfecting the NP69 cells with an EBER‐expressing plasmid, pESK10. The EBER‐expressing NP69 cells attained a higher growth rate compared to cells transfected with control plasmid (pcDNA3). However, the EBER‐expressing NP69 cells did not form colonies in soft agar and were non‐tumorigenic in nude mice. To investigate if EBERs may protect the nasopharyngeal epithelial cells from apoptotic insults, we treated the EBER‐expressing NP69 cells with a dsRNA analogue, poly(I).poly(C) (pIC), to activate PKR in cells and examined for their responses. Lower level of PKR phosphorylation and elevation of Bcl‐2 were observed in EBER‐expressing NP69 cells. In addition, other apoptotic markers including the cleaved forms of caspase‐3 and poly(ADP)ribose polymerase (PARP) were found to be lower in EBER‐expressing NP69 cells after treatment with pIC. Lower phosphorylation levels of p38 MAPK (mitogen‐activated protein kinase) and c‐jun were also observed in EBER‐expressing NP cells. Our results suggest that EBER expression may confer an apoptotic‐resistant phenotype in immortalized nasopharyngeal epithelial cells. © 2005 Wiley‐Liss, Inc.
Development of ultra short‐acting muscle relaxant agents: History, research strategies, and challenges
Authors: Gyermek Laszlo 
Published: August 2005

AbstractAuthor has reviewed the literature and his own work related to the chemistry, pharmacology, and clinical aspects of new muscle relaxants. Emphasis has been placed on the basic science concepts and technologies (e.g. structure–activity relationships, nicotinic receptor pharmacology, and investigation of side effects) behind the development of rapidly and short acting nondepolarizing muscle relaxants. © 2005 Wiley Periodicals, Inc.
Simultaneous spin‐echo refocusing
Authors: Günther Matthias , Feinberg David A. 
Published: August 2005

AbstractA new approach to spin‐echo imaging is presented in which the 180° RF pulse refocuses two or more spin‐echoes at different positions in the readout period. When simultaneous echo refocusing (SER) is implemented using multiple 180° pulses, an undesirable mixing of stimulated echoes and primary echoes from different slices can occur. A novel periodic gradient spoiler scheme eliminates this potential source of artifacts without spoiling the correctly timed stimulated echoes, which, similar to RARE (TSE) sequences, add coherently to the primary echoes. Comparisons show equivalent artifact elimination using phase cycling, periodic spoiling, and a previously developed spoiling scheme for non‐Carr–Purcell–Meiboom–Gill sequences. A comparison of head images at 1.5 T acquired with SER‐TSE and conventional TSE T1‐weighted sequences show no degradation in image quality nor SNR. T2‐weighted imaging is not achievable with the current implementation, but possible solutions are proposed. The proposed technique might prove especially beneficial at higher field strengths, where the reduced number of refocusing pulses for multislice SER‐TSE decreases RF power deposition. SER spin‐echo imaging offers an approach that is very different from low flip angle imaging to mitigate RF heating limitations in high‐field clinical imaging. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Fast spin‐echo for multiple mouse magnetic resonance phenotyping
Authors: Nieman Brian J. , Bock Nicholas A. , Bishop Johnathan , Sled John G. , Josette Chen X. , Mark Henkelman R. 
Published: August 2005

AbstractHigh‐resolution magnetic resonance imaging is emerging as a powerful tool for phenotyping mice in biologic studies of genetic expression, development, and disease progression. In several applications, notably random mutagenesis trials, large cohorts of mice must be examined for abnormalities that may occur in any part of the body. In the aim of establishing a protocol for imaging multiple mice simultaneously in a standardized high‐throughput fashion, this study investigates variations of a three‐dimensional fast spin‐echo sequence that implements driven equilibrium, modified refocusing, and partial excitation pulses. Sequence variations are compared by simulated and experimental measurements in phantoms and mice. Results indicate that when using a short repetition time (TR ≤ T1) a sequence employing a partial excitation tip angle provides both improved signal and good T2 contrast compared with standard fast spin‐echo imaging. This sequence is used to simultaneously acquire four live mouse head images at 100 μm isotropic resolution with a scan time under 3 h at 7 T. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Simultaneous water and lipid suppression for in vivo brain spectroscopy in humans
Authors: Smith Mari A. , Gillen Joseph , McMahon Michael T. , Barker Peter B. , Golay Xavier 
Published: August 2005

AbstractA method to achieve simultaneous water and lipid suppression is described. The key feature of the new dual suppression technique is the use of the well‐known hyperbolic secant (HS) waveform as a 90° saturation pulse. Two HS pulses with opposite frequency offsets are employed either sequentially or simultaneously to saturate resonance frequencies corresponding to water and lipid, while leaving the target spins untouched. The excitation bandwidth is controlled by the frequency sweep and offset of each pulse, while varying the pulse length controls the transition bandwidth. An example of the use of the dual saturation method in in vivo magnetic resonance spectroscopic imaging of the human brain is presented. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Broadband multicoil imaging using multiple demodulation hardware: A feasibility study
Authors: Lee Jin Hyung , Scott Greig C. , Pauly John M. , Nishimura Dwight G. 
Published: August 2005

AbstractMultiple receiver‐coil data collection is an effective approach to reduce scan time. There are many parallel imaging techniques that reduce scan time using multiple receiver coils. One of these methods, partially parallel imaging with localized sensitivities (PILS), utilizes the localized sensitivity of each coil. The advantages of PILS over other parallel imaging methods include the simplicity of the algorithm, good signal‐to‐noise ratio (SNR) properties, and the fact that there is no additional complexity involved in applying the algorithm to arbitrary k‐space trajectories. This PILS method can be further improved to provide truly parallel broadband imaging with the use of multiple‐demodulation hardware. By customizing the demodulation based on each coil's location, the k‐space sampling rate can be chosen based on each coil's localized sensitivity region along the readout direction. A simulated demodulation of data from 2D Fourier transform (FT) and spiral trajectories is shown to demonstrate the method's feasibility. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Hemispherical gradient coils for magnetic resonance imaging
Authors: Green Dan , Leggett James , Bowtell Richard 
Published: August 2005

AbstractHemispherical gradient coils offer an open geometry that is well suited to imaging of the human brain. The windings of a hemispherical gradient coil are on average closer to the target region than those of a comparable cylindrical coil, and consequently hemispherical coils can produce higher efficiency at fixed inductance. The mathematical formalism needed for the design of hemispherical gradient coils is described here, including expressions relating the current distribution on the hemisphere to the magnetic field generated, as well as the stored energy and power dissipation. In addition, expressions for the torque experienced by the current distribution in the presence of the main magnetic field have been derived and used to develop an approach allowing the design of torque‐balanced, hemispherical transverse gradient coils. Hemispherical coil designs suitable for brain imaging are presented and shown to have improved performance compared with their cylindrical counterparts. Small, prototype, hemispherical z‐ and x‐gradient coils have been constructed and tested in phase‐mapping experiments at 3 T. The experimental results show good agreement with theoretical predictions, validating the mathematical expressions used in the coil design process. The formalism also allows the design of coils wound on a complete spherical surface, and the performance of such coils is additionally described here. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
T1, T2 relaxation and magnetization transfer in tissue at 3T
Authors: Stanisz Greg J. , Odrobina Ewa E. , Pun Joseph , Escaravage Michael , Graham Simon J. , Bronskill Michael J. , Henkelman R. Mark 
Published: August 2005

AbstractT1, T2, and magnetization transfer (MT) measurements were performed in vitro at 3 T and 37°C on a variety of tissues: mouse liver, muscle, and heart; rat spinal cord and kidney; bovine optic nerve, cartilage, and white and gray matter; and human blood. The MR parameters were compared to those at 1.5 T. As expected, the T2 relaxation time constants and quantitative MT parameters (MT exchange rate, R, macromolecular pool fraction, M0B, and macromolecular T2 relaxation time, T2B) at 3 T were similar to those at 1.5 T. The T1 relaxation time values, however, for all measured tissues increased significantly with field strength. Consequently, the phenomenological MT parameter, magnetization transfer ratio, MTR, was lower by approximately 2 to 10%. Collectively, these results provide a useful reference for optimization of pulse sequence parameters for MRI at 3 T. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Biexponential parameterization of diffusion and T2 relaxation decay curves in a rat muscle edema model: Decay curve components and water compartments
Authors: Ababneh Zaid , Beloeil Helene , Berde Charles B. , Gambarota Giulio , Maier Stephan E. , Mulkern Robert V. 
Published: August 2005

AbstractQuantitative T2 relaxation and diffusion imaging studies of a rat muscle edema model were performed in order to determine the effects of intra‐ and extracellular water compartmentation on the respective decay curves. The right hind paw of rats was injected with a carrageenan solution to generate edematous muscle. A Carr–Purcell–Meiboom–Gill (CPMG) imaging sequence was used to acquire T2 relaxation decay curves from both paws. A line scan diffusion imaging (LSDI) sequence was then used to acquire diffusion decay curves from the same paws over a wide b‐factor range. Measurements were made from both edematous muscle (EM) and control muscle (CM). The EM and CM T2 relaxation decay curves were best fit with biexponential functions. The fraction of the fast T2 component dropped dramatically from approximately 0.95 in CM to 0.45 in EM, consistent with a water compartmentation model in which the fast and slow T2 components reflect intra‐ and extracellular water, respectively. Both CM and EM diffusion decay curves required biexponential fitting functions, and the diffusion coefficients of the fast and slow components were substantially larger in EM than CM. The fraction of the fast diffusion component, however, was not radically altered between CM and EM conditions (0.84 versus 0.89 for CM versus EM). Assuming a model in which intra‐ and extracellular water compartments are responsible for the fast and slow T2‐decay components and for the slow and fast diffusion decay components, respectively, leads to fractional sizes of the diffusion components that are not supported by experiment. We conclude that intra‐ and extracellular water compartmentation is a reasonable interpretation for the two T2‐decay components in both CM and EM but that other factors, such as restricted diffusion and/or alternate forms of water compartmentation like surface versus volume water, most probably have profound influences on the precise shapes of the diffusion decay curves, a complete understanding of which will require significant theoretical work. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.