bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro assessment of bioactive coatings for neural implant applications
Authors: Massia Stephen P. , Holecko Matthew M. , Ehteshami Gholam R. 
Published: December 2003

AbstractRecent efforts in our laboratory have focused on developing methods for immobilizing bioactive peptides to low cell‐adhesive dextran monolayer coatings and promoting biospecific cell adhesion for biomaterial implant applications. In the current study, this dextran‐based bioactive coating technology was developed for silicon, polyimide, and gold, the base materials utilized to fabricate our prototype neural implants. Chemical composition of all modified surfaces was verified by X‐ray photoelectron spectroscopy (XPS). We observed that surface‐immobilized dextran supported very little cell adhesion in vitro (24‐h incubation with serum‐supplemented medium) on all base materials. Inactive nonadhesion‐promoting Gly‐Arg‐Ala‐Asp‐Ser‐Pro peptides immobilized on dextran‐coated materials promoted adhesion and spreading at low levels not significantly different from dextran‐coated substrates. Arg‐Gly‐Asp (RGD) peptide‐grafted surfaces were observed to promote substantial fibroblast and glial cell adhesion with minimal PC12 (neuronal cell) adhesion. In contrast, dextran‐coated materials with surface‐grafted laminin‐based, neurite‐promoting Ile‐Lys‐Val‐Ala‐Val (IKVAV) peptide promoted substantial neuron cell adhesion and minimal fibroblast and glial cell adhesion. It was concluded that neuron‐selective substrates are feasible using dextran‐based surface chemistry strategies. The chemical surface modifications could be utilized to establish a stable neural tissue–implant interface for long‐term performance of neural prosthetic devices. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 177–186, 2004
Collagen–hydroxyapatite composite prepared by biomimetic process
Authors: Lickorish David , Ramshaw John A. M. , Werkmeister Jerome A. , Glattauer Veronica , Howlett C. Rolfe 
Published: December 2003

AbstractA novel bone graft substitute comprising a porous, collagenous scaffold was biomimetically coated with hydroxyapatite using a simulated body fluid solution chemistry method. The scaffold had a porosity of approximately 85%, with pore sizes between 30 μm and 100 μm. Glutaraldehyde vapor was used to stabilize the collagenous scaffold, giving a significantly increased thermal stability over an unstabilized scaffold, as shown by differential scanning calorimetry. A thin layer (<10 μm) of crystalline hydroxyapatite was deposited onto the stabilized collagenous scaffold by soaking the collagenous construct in simulated body fluid in the presence of calcium silicate glass. The presence of crystalline hydroxyapatite was confirmed by X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, and scanning electron microscopy. In vitro cytotoxicity testing of the composite construct using L‐929 fibroblasts (ISO 10993‐5) and rabbit periosteal cells revealed a cytocompatible material that supported cellular attachment and proliferation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 19–27, 2004
EDTA‐induced activation of Ca‐regulated proteins in the vaginal mucosa
Authors: Sang Choe Eun , Warrier Bharat , Soo Chun Jang , Cheol Park Joo , Lee Chi H. 
Published: December 2003

AbstractThe effects of EDTA on the expression and topologic localization of mitogen‐activated protein (MAP) kinases (ERK, JNK, and p38), along with nitric oxide synthase (NOS), I‐KappaB, and p53 were examined to elucidate the host response provoked by the intravaginal application of a female controlled drug delivery system (FcDDS) containing a spermicidal/microbicidal agent and EDTA. Immunohistochemical and immunoblotting studies were conducted to identify and quantitate the EDTA‐inducible proteins in vaginal mucosa. The content of nitrite, which is one of the primary stable breakdown products of nitric oxide (NO), was determined to correlate the expression of NOS with NO formation in HeLa cervical carcinoma cell line. The immunohistochemical study demonstrated that the modulation of the calcium gradient by EDTA activated MAP kinases (ERK and JNK) in the rabbit vaginal mucosa. The results of Western immunoblot study demonstrated differential expression of MAP kinases (ERK and JNK) with EDTA treatment, whereas the expression of NOS and NF‐KappaB was not affected by EDTA. There was no significant difference in nitrite production in the HeLa cell line upon exposure to EDTA compared with the control, which was consistent with the results of the Western blot study. The results of this work support that the regulation of MAP kinase was affected by calcium, which is controlled by chelation activity of EDTA. The specific tissue responses exerted by the loading components of a biomaterial‐based system should be fully taken into consideration for its intravaginal application. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 159–167, 2004
Refrigeration of rainbow trout gametes and embryos
Authors: Babiak Igor , Dabrowski Konrad 
Published: December 2003

AbstractProlonged access to early embryos composed of undifferentiated, totipotent blastomeres is desirable in situations when multiple collections of gametes are not possible. The objective of the present study is to examine whether the refrigeration of rainbow trout Oncorhynchus mykiss gametes and early embryos would be a suitable, reliable, and efficient tool for prolonging the availability of early developmental stages up to the advanced blastula stage. The study was conducted continuously during fall, winter, and spring spawning seasons. In all, more than 500 experimental variants were performed involving individual samples from 26 females and 33 males derived from three strains. These strains represented three possible circumstances. In optimal one, gametes from good quality donors were obtained soon after ovulation. In the two non‐optimal sources, either donors were of poor genetic quality or gametes were collected from a distant location and transported as unfertilized gametes. A highly significant effect of variability of individual sample quality on efficiency of gamete and embryo refrigeration was revealed. The source of gametes significantly affected viability of refrigerated oocytes and embryos, but not spermatozoa. On average, oocytes from optimal source retained full fertilization viability for seven days of chilled storage, significantly longer than from non‐optimal sources. Spermatozoa, regardless of storage method, retained full fertilization ability for the first week of storage. Refrigeration of embryos at 1.4±0.4°C significantly slowed the development. Two‐ week‐old embryos were still in blastula stage. Average survival rate of embryos refrigerated for 10 days and then transferred to regular incubation temperatures of 9–14°C was 92% in optimal and 51 and 71% in non‐optimal source variants. No effect of gamete and embryo refrigeration on the occurrence of developmental abnormalities was observed. Cumulative refrigeration of oocytes and embryos resulted in an average embryo survival rate of 71% in optimal source variants after 17 days of refrigeration (7 days oocytes+10 days embryos). The study shows that both gamete and embryo refrigeration can be successfully used as an efficient tool for prolonging availability of rainbow trout embryos in early developmental stages. J. Exp. Zool. 300A:140–151, 2003. © 2003 Wiley‐Liss, Inc.
ARNT gene multiplicity in amphibians: Characterization of arnt2 from the frog Xenopus laevis
Authors: Rowatt Ashley J. , Depowell John J. , Powell Wade H. 
Published: December 2003

AbstractThe aryl hydrocarbon receptor nuclear translocator (ARNT) is a member of the Per‐ARNT‐Sim (PAS) protein superfamily, transcription factors that mediate the cellular responses to various developmental signals and environmental conditions. A β‐class (“partner”) PAS protein, ARNT exhibits the capacity to form transcriptionally active heterodimers with several α‐class (“sensor”) proteins, including the aryl hydrocarbon receptors (AHRs), the hypoxia‐inducible factors (HIFs), and the Single minded (Sim) proteins. Two genes encode different forms of ARNT in mammals: ARNT1, which is widely expressed, and ARNT2, which is limited to the brain and kidneys of adults and specific neural and branchial tissues of embryos. In contrast, fish apparently express only a single ARNT gene, although in different species, this may be either ARNT1 or ARNT2. In efforts to understand the evolution of ARNT proteins throughout the vertebrate lineage, we isolated an ARNT cDNA from early life stages of the amphibian Xenopus laevis. The encoded protein binds cognate DNA sequences in concert with mouse AHR. Phylogenetic analysis reveals that this sequence is orthologous to mammalian ARNT2 and paralogous to the recently reported X. laevis ARNT1. ARNT2 mRNA expression begins later than ARNT1 (stage 22 vs. stage 8), suggesting the two proteins play distinct roles during development. Hence, in the expression of two well‐conserved ARNT paralogs with distinct expression patterns, X. laevis resembles mammals rather than fish. Diversity in the number and function of PAS proteins, including ARNT, may underlie significant species differences in developmental programming and biochemical response to environmental conditions. The identification of multiple amphibian ARNT paralogs represents an important step in the understanding of evolution and functional variation of ARNT in vertebrates. J. Exp. Zool. (Mol. Dev. Evol.) 300B:48–57, 2003. © 2003 Wiley‐Liss, Inc.
One eye but no vision: Cave fish with induced eyes do not respond to light
Authors: Romero Aldemaro , Green Steven M. , Romero Andrea , Lelonek Megan M. , Stropnicky Katy C. 
Published: December 2003

AbstractOne of the most intriguing questions in evolutionary biology is the degree to which behavior is a necessary consequence of morphology. We explore this issue by examining phototactic behavior in epigean (eyed surface‐dwelling) and troglomorphic (blind cave) forms of the teleost Astyanax fasciatus whose eyes were modified during embryogenesis by removing one or both lens vesicles from the epigean form or by transplanting the lens vesicle from an epigean fish into the optic cup of a blind cave form. Lens removal results in eye degeneration and blindness in adult epigean fish, whereas lens transplantation stimulates growth of the eye, inducing the development of optic tissues in the normally eyeless adult cave fish. Photoresponsiveness was examined by placing fish in an aquarium with one half illuminated and the other half dark and scoring their presence in the illuminated or dark half. Both the eyeless epigean fish and cave fish with induced eyes are indifferent to the illumination whereas the surface forms are scotophilic, suggesting that optic development and phototactic behavior are decoupled. J. Exp. Zool. (Mol. Dev. Evol.) 300B:72–79, 2003. © 2003 Wiley‐Liss, Inc.
Complete classification of tournaments having a disjoint union of directed paths as a minimum feedback arc set
Authors: Isaak Garth , Narayan Darren A. 
Published: December 2003

AbstractA feedback arc set of a digraph is a set of arcs whose reversal makes the resulting digraph acyclic. Given a tournament with a disjoint union of directed paths as a feedback arc set, we present necessary and sufficient conditions for this feedback arc set to have minimum size. We will present a construction for tournaments where the difference between the size of a minimum feedback arc set and the size of the largest collection of arc disjoint cycles can be made arbitrarily large. We will also make a connection to a problem found in [Barthélemy et al., 2]. The reversing number of a digraph was defined to be $r(D)\, = |V(T)|-|V(D)|$ where T is a smallest tournament having the arc set of D as a minimum feedback arc set. As a consequence of our classification of all tournaments having a disjoint union of directed paths as a minimum feedback arc set, we will obtain a new result involving the reversing number. We obtain precise reversing numbers for all digraphs consisting of a disjoint union of directed paths. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 28–47, 2004
Neutral loss of amino acid residues from protonated peptides in collision‐induced dissociation generates N‐ or C‐terminal sequence ladders
Authors: Salek Mogjiborahman , Lehmann Wolf D. 
Published: December 2003

AbstractThe widespread occurrence of the neutral loss of one to six amino acid residues as neutral fragments from doubly protonated tryptic peptides is documented for 23 peptides with individual sequences. Neutral loss of amino acids from the N‐terminus of doubly charged tryptic peptides results in doubly charged y‐ions, forming a ladder‐like series with the ions [M + 2H]2+ = ymax2+, ymax − 12+, ymax − 22+, etc. An internal residue such as histidine, proline, lysine or arginine appears to favor this type of fragmentation, although it was sometimes also observed for peptides without this structure. For doubly protonated non‐tryptic peptides with one of these residues at or near the N‐terminus, we observed neutral loss from the C‐terminus, resulting in a doubly charged b‐type ion ladder. The analyses were performed by Q‐TOF tandem mass spectrometry, facilitating the recognition of neutral loss ladders by their 2+ charge state and the conversion of the observed mass differences into reliable sequence information. It is shown that the neutral loss of amino acid residues requires low collision offset values, a simple mechanistic explanation based on established fragmentation rules is proposed and the utility of this neutral loss fragmentation pathway as an additional source for dependable peptide sequence information is documented. Copyright © 2003 John Wiley & Sons, Ltd.
Evaluation of the metal binding properties of a histidine‐rich fusogenic peptide by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry
Authors: Sinz Andrea , Jin Albert J. , Zschörnig Olaf 
Published: December 2003

AbstractElectrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICRMS) was used to investigate metal ion interactions of the 18 amino acid peptide fragment B18 (LGLLLRHLRHHSNLLANI), derived from the membrane‐associated protein bindin. The peptide sequence B18 represents the minimal membrane‐binding motif of bindin and resembles a putative fusion peptide. The histidine‐rich peptide has been shown to self‐associate into distinct supramolecular structures, depending on the presence of Zn2+ and Cu2+. We examined the binding of B18 to the metal ions Cu2+, Zn2+, Mg2+, Ca2+, Mn2+ and La3+. For Cu2+, we compared the metal binding affinities of the wild‐type B18 peptide with those of its mutants in which one, two or three histidine residues have been replaced by serines. Upon titration of B18 with Cu2+ ions, we found sequential binding of two Cu2+ ions with dissociation constants of ∼34 and ∼725 µM. Mutants of B18, in which one histidine residue is replaced by serine, still exhibit sequential binding of two copper ions with affinities for the first Cu2+ ion comparable to that of wild‐type B18 peptide, but with a greatly reduced affinity for the second Cu2+ ion in mutants H112S and H113S. For mutants in which two histidines are replaced by serines, the affinity for the first Cu2+ ion is reduced ∼3–10 times in comparison with B18. The mutant in which all three histidine residues are replaced by serines exhibits an ∼14‐fold lower binding for the first Cu2+ ion compared with B18. For the other metal ions under investigation (Zn2+, Mg2+, Ca2+, Mn2+ and La3+), a modest affinity to B18 was detected binding to the peptide in a 1 : 1 stoichiometry. Our results show a high affinity of the wild‐type fusogenic peptide B18 for Cu2+ ions whereas the Zn2+ affinity was found to be comparable to that of other di‐ and trivalent metal ions. Copyright © 2003 John Wiley & Sons, Ltd.
A derivatization assay using gaschromatography/negative chemical ionization tandem mass spectrometry to quantify 3‐nitrotyrosine in human plasma
Authors: Söderling Ann‐Sofi , Ryberg Henrik , Gabrielsson Anders , Lärstad Mona , Torén Kjell , Niari Sohbat , Caidahl Kenneth 
Published: December 2003

AbstractEndogenous free or protein‐associated 3‐nitrotyrosine (3‐NT) has been proposed as a biomarker of in vivo oxidative damage caused by nitrating agents. Isotopic dilution assay gaschromatographic/mass spectrometric (GC/MS) techniques have been employed to measure endogenous 3‐NT levels. However, the quantitative normal plasma values reported so far are inconsistent. The results vary between the assays; they may have been influenced by in vitro artifactual nitration of tyrosine to 3‐NT. In this study, a simple and artifact‐free derivatization method for quantifying the endogenous 3‐NT content of biological samples by GC/negative chemical ionization MS/MS is presented. The method is based on reduction of the nitro group of the molecule by dithionite, heptafluorobutyric acylation and subsequent methyl derivatization, di‐O‐methyldi‐N‐heptafluorobutyryl being the major derivative. The results showed excellent GC and MS properties, such as low background and a favorable fragmentation pattern. Endogenous 3‐NT was unequivocally quantified using collision‐induced dissociation in the selected reaction monitoring mode, whereas co‐elution of unknown compounds interfered in the selected‐ion monitoring mode. We found that tyrosine was nitrated in the presence of nitrate anions and heptafluorobutyric anhydride, but the product appeared as a di‐O‐methylmono‐N‐heptafluorobutyryl derivative. Therefore, artifactually formed 3‐NT did not contribute to the measured endogenous 3‐NT level owing to its different derivative structure. The method was applied to determine endogenous 3‐NT in human plasma and plasma proteins. A detection limit of 0.03 nM for 13C6‐labeled 3‐NT in plasma samples was established and the response was linear over a concentration range of 0–50 nM (R2 > 0.999). The endogenous free 3‐NT level (mean ± SD) in ultrafiltered plasma samples from 12 healthy adults was 0.74 ± 0.30 nM. The mean concentration of 3‐NT in their plasma total proteins was 0.60 ± 0.40 pmol mg−1. Hence, the described method is selective, eliminates the problem of artifactual nitration and is feasible for the quantification of free and protein‐associated 3‐NT in biological samples such as plasma. Copyright © 2003 John Wiley & Sons, Ltd.
Multi‐turn time‐of‐flight mass spectrometers with electrostatic sectors
Authors: Toyoda Michisato , Okumura Daisuke , Ishihara Morio , Katakuse Itsuo 
Published: December 2003

AbstractThe mass resolution of a time‐of‐flight (TOF) mass spectrometer is directly proportional to its total flight pathlength. Multi‐turn or multi‐passage ion optical geometries are necessary to obtain fight distances of sufficient length within reasonable size limitations. We have investigated ion optics for a multi‐turn TOF mass spectrometer with electrostatic sectors. The concept of ‘perfect’ focusing conditions is introduced. Furthermore, a new type of multi‐turn TOF mass spectrometer, the MULTUM Linear plus, was developed. It consists of four cylindrical electric sectors and 28 electric quadrupole lenses. It has a vacuum chamber 60 × 70 × 20 cm in size. Mass resolution is demonstrated to increase according to the number of ion cycles. A mass resolution of 350 000 (m/z = 28, FWHM) was achieved after 501.5 cycles. The MULTUM Linear plus analyzer is not simple, however; 28 electric quadrupole lenses are used. In order to reduce the number of ion optical parts, an improved multi‐turn TOF mass spectrometer, the MULTUM II, consisting of only four toroidal electric sectors, was also developed. The possibility of tandem mass spectrometric applications using multi‐turn TOF mass spectrometers is also discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Suppression of ammonia‐induced astrocyte swelling by cyclosporin A
Authors: Rama Rao K.V. , Chen M. , Simard J.M. , Norenberg M.D. 
Published: December 2003

AbstractBrain edema is a serious complication of hepatic encephalopathy associated with fulminant hepatic failure (FHF). A major component of the edema seems to be cytotoxic, involving astrocyte swelling. Although the mechanism of brain edema in FHF is incompletely understood, it is generally believed that ammonia is involved critically in this process. Recent studies have shown that exposure of cultured astrocytes to ammonia results in the mitochondrial permeability transition (MPT), a phenomenon associated with mitochondrial failure and subsequent cellular dysfunction. The present study examined the potential role of the MPT in the astrocyte swelling associated with ammonia toxicity. Treatment of cultured astrocytes with ammonia (5 mM) caused a time‐dependent increase in astrocyte cell volume (swelling), which was completely inhibited by the MPT inhibitor cyclosporin A (CsA). In this study, CsA also inhibited the ammonia‐induced aquaporin 4 (AQP4) upregulation, which had been shown previously to be increased in cultured astrocytes by ammonia treatment. These findings suggest that the MPT plays a significant role in the ammonia‐induced astrocyte swelling and may contribute to the brain edema associated with FHF. © 2003 Wiley‐Liss, Inc.
DNA microarray cluster analysis reveals tissue similarity and potential neuron‐specific genes expressed in cranial sensory ganglia
Authors: Matsumoto Ichiro , Emori Yasufumi , Nakamura Shugo , Shimizu Kentaro , Arai Soichi , Abe Keiko 
Published: December 2003

AbstractEach of four cranial sensory ganglia, trigeminal, geniculate, petrosal, and nodose ganglia, contains multiple kinds of sensory neurons with different cell morphologies and neuronal properties that transmit information about sensory stimuli received peripherally. Here we analyze the complex properties of these neurons from the viewpoint of gene expression using DNA microarrays by cluster analysis. From a total of 8,740 genes, 498 genes were selected as showing tissue‐dependent expression on the microarray by hierarchical cluster analysis, and their profiles indicated that, among the four sensory ganglia, the petrosal and trigeminal ganglia are intimately related. Tissue trees of 37 subclusters containing the 498 genes showed that the profiles of gene expression and the subclusters were classified into a smaller number of groups (18 groups) when information on the amounts of expression was added. In situ hybridization analysis of 21 genes selected from 13 different groups was carried out, and the gene expression patterns were classified into eight categories. The putative profiles postulated from the microarray data were essentially consistent with the patterns of expression at the cellular level as shown by in situ hybridization. In conclusion, from the overall analyses of gene expression by DNA microarray, we can identify a number of candidate genes showing neuron type‐specific expression in the peripheral ganglia. © 2003 Wiley‐Liss, Inc.
p38 Mitogen‐activated protein kinase modulates expression of tumor necrosis factor‐related apoptosis‐inducing ligand induced by interferon‐γ in fetal brain astrocytes
Authors: Lee J. , Shin J.‐S. , Park J.Y. , Kwon D. , Choi S.‐J. , Kim S.‐J. , Choi I.‐H. 
Published: December 2003

AbstractThis study describes the involvement of the p38 mitogen‐activated protein kinase (MAPK) during interferon‐γ (IFN‐γ) signaling in fetal brain astrocytes. In some pathological conditions of brain, p38 MAPK transduces stress‐related signals, increases expression of proinflammatory cytokines, and induces cellular damage or apoptosis. In astrocytes, the tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) expression level was increased by IFN‐γ. AG490, a JAK inhibitor, blocked TRAIL expression induced by IFN‐γ. SB203580, a specific p38α and p38β2 MAPK inhibitor, decreased the TRAIL expression induced by IFN‐γ. The phosphorylation of the Ser727 site of STAT1, but not the Tyr701 site, was inhibited by SB203580. These results suggest that p38 MAPK modulates STAT1 phosphorylation in IFN‐γ signaling in fetal brain astrocytes. © 2003 Wiley‐Liss, Inc.