bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nodal signaling promotes the speed and directional movement of cardiomyocytes in zebrafish
Authors: de Campos‐Baptista Maria Ines Medeiros , Holtzman Nathalia Glickman , Yelon Deborah , Schier Alexander F. 
Published: November 2008

AbstractMembers of the Nodal family regulate left‐right asymmetry during vertebrate organogenesis, but it is unclear how Nodal signaling controls asymmetric morphogenesis at the cellular level. We used high‐resolution time‐lapse imaging in zebrafish to compare the movements of cardiomyocytes in the presence or absence of Nodal signaling. Loss of Nodal signaling in late‐zygotic mutants for the Nodal co‐receptor one‐eyed pinhead (LZoep) abolished the leftward movement of cardiomyocytes. Global heart rotation was blocked but cardiomyocyte neighbor relationships were maintained as in wild type. Cardiomyocytes in LZoep mutants moved more slowly and less directionally than their wild‐type counterparts. The phenotypes observed in the absence of Nodal signaling strongly resemble abnormalities found in BMP signaling mutants. These results indicate that a Nodal‐BMP signaling cascade drives left‐right heart morphogenesis by regulating the speed and direction of cardiomyocyte movement. Developmental Dynamics 237:3624–3633, 2008. © 2008 Wiley‐Liss, Inc.
Erbium‐Complex‐Doped Near‐Infrared Luminescent and Magnetic Macroporous Materials
Authors: Fan Wei‐Qiang , Feng Jing , Song Shu‐Yan , Lei Yong‐Qian , Xing Yan , Deng Rui‐Ping , Dang Song , Zhang Hong‐Jie 
Published: November 2008

AbstractA near‐infrared luminescent macroporous material (PL–Macromaterial) and a near‐infrared luminescent/magnetic bifunctional macroporous material (M/PL–Macromaterial) were synthesized by using polystyrene microspheres(PS) and Fe3O4@polystyrene core–shell nanoparticles (Fe3O4@PS), respectively, as templates. Both the PL–Macromaterial and the M/PL–Macromaterial show the characteristic emission of the Er3+ ion. Moreover, the M/PL–Macromaterial possesses superparamagnetic properties at roomtemperature. The photoluminescence, magnetism, and macroporous morphologies of the macroporous materals were investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Functional Porphyrinoids from a Biomimetically Decorated Bipyrrole
Authors: Bröring Martin , Brégier Frédérique , Krüger Robin , Kleeberg Christian 
Published: November 2008

AbstractThe known 5,5′‐diformyl‐3,3′‐bis(methoxycarbonylethyl)‐4,4′‐dimethyl‐2,2′‐bipyrrole was employed in the preparation of biomimetic functional porphyrinoids. Tetrapyrrolic 2,2′‐bidipyrrins could be obtained from condensations with two equivalents of 3,4‐dialkyl‐2‐methylpyrroles. From these compounds, a manganese(III) corrole as well as a boron‐containing bis(bodipy) fluorophor are accessible as functional species in one‐step reactions. Both products were investigated by means of X‐ray crystallography. Attempts to hydrolyze the methyl ester moieties were successful only for the manganese corrole and yielded a buffer–soluble, heme‐analogous corrole complex. The dinuclear BF2 chelate [bis(bodipy)], on the other hand, decomposes unselectively under the applied conditions. A rationale for this decomposition was derived from crystallographic work on a related hydrolysis product with a F–B–O–B–F moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Manufacturing and PEGylation of a Dual‐Acting Peptide for Diabetes
Authors: Krüger Jochen , Minuth Torsten , Schröder Werner , Werwath Jörn 
Published: November 2008

AbstractIn the given manuscript we summarize our activities to develop a scalable synthesis for a PEGylated peptide, which undergoes development for metabolic disorders. The polypeptide contains a sequence of 31 natural amino acids and carries a site‐specific PEGylation at the C‐terminus. Initial synthetic studies revealed that the peptide moiety of the target molecule is not an ideal target for a linear solid‐phase process, as we were confronted with “difficult sequences”, which led to a low‐yielding process. Subsequently, we developed a mixed‐phase synthesis, which included production of fragments through solid‐phase peptide synthesis, followed by an assembly of these fragments in solution. We were able to show that this new process delivered the desired peptide moiety in gram‐scale with high purity. The overall yield was improved from 1 % for the sequential solid‐phase process to 9 % for the fragment synthesis. Finally, a PEGylation process was installed to deliver the drug substance for preclinical and clinical testing. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Solid‐State Fluorescence Changes of 2‐(4‐Cyanophenyl)‐5‐[4‐(diethylamino)phenyl]‐3H‐imidazo[4,5‐a]naphthalene upon Inclusion of Organic Solvent Molecules
Authors: Ooyama Yousuke , Nagano Shinobu , Okamura Miyako , Yoshida Katsuhira 
Published: November 2008

AbstractNovel imidazo[4,5‐a]naphthalene‐type fluorescent clathrate host 2‐(4‐cyanophenyl)‐5‐[4‐(diethylamino)phenyl]‐3H‐imidazo[4,5‐a]naphthalene (2), with two possible tautomeric forms (A and B) of the imidazole ring, was developed. The crystal of fluorophore 2 exhibits sensitive colour change and fluorescence enhancement behaviour with a blueshift in the emission maximum upon enclathration of various kinds of organic solvent molecules. The crystal structures of the guest‐free and clathrate compounds of 2 were determined by X‐ray analysis. On the basis of spectroscopic data and crystal structures, the effects of the enclathrated guest on the solid‐state photophysical properties of the clathrate compounds are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Direct Electrochemistry of Hemoglobin and Its Electrocatalysis Based on Hyaluronic Acid and Room Temperature Ionic Liquid
Authors: Gao Ruifang , Shangguan Xiaodong , Qiao Guangjun , Zheng Jianbin 
Published: November 2008

AbstractA biocomposite material of hyaluronic acid (HA) and room temperature ionic liquid, 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate (BMIMBF4) was fabricated and characterized by voltammetry and electrochemical impedance spectroscopy. Hemoglobin (Hb), as a model protein, was immobilized in this biocomposite on glassy carbon electrode to investigate its direct electrochemistry. A pair of well‐defined, quasireversible cyclic voltammetric peaks appeared with the formal potentials (E°′) at −0.360 V (vs. SCE). The Hb modified electrode exhibited an excellent electrocatalytic activity to the reduction of H2O2 with a wide linear range, good selectivity, sensitivity and reproducibility, which had potential application to fabrication the third‐generation biosensor.
On the stability of bubble functions and a stabilized mixed finite element formulation for the Stokes problem
Authors: Turner D. Z. , Nakshatrala K. B. , Hjelmstad K. D. 
Published: November 2008

AbstractIn this paper we investigate the relationship between stabilized and enriched finite element formulations for the Stokes problem. We also present a new stabilized mixed formulation for which the stability parameter is derived purely by the method of weighted residuals. This new formulation allows equal‐order interpolation for the velocity and pressure fields. Finally, we show by counterexample that a direct equivalence between subgrid‐based stabilized finite element methods and Galerkin methods enriched by bubble functions cannot be constructed for quadrilateral and hexahedral elements using standard bubble functions. Copyright © 2008 John Wiley & Sons, Ltd.
Uncoupling of neurodegeneration and gliosis in a murine model of juvenile cortical lesion
Authors: Sargin Derya , Hassouna Imam , Sperling Swetlana , Sirén Anna‐Leena , Ehrenreich Hannelore 
Published: November 2008

AbstractA small experimental cryolesion to the right parietal cortex of juvenile mice causes late‐onset global brain atrophy with memory impairments, reminiscent of cognitive decline, and progressive brain matter loss in schizophrenia. However, the cellular events underlying this global neurodegeneration are not understood. Here we show, based on comprehensive stereological analysis, that early unilateral lesion causes immediate and lasting bilateral increase in the number of microglia in cingulate cortex and hippocampus, consistent with a chronic low‐grade inflammatory process. Whereas the total number of neurons and astrocytes in these brain regions remain unaltered, pointing to a non‐ gliotic neurodegeneration (as seen in schizophrenia), the subgroup of parvalbumin‐positive inhibitory GABAergic interneurons is increased bilaterally in the hippocampus, as is the expression of the GABA‐synthesizing enzyme GAD67. Moreover, unilateral parietal lesion causes a decrease in the expression of synapsin1, suggesting impairment of presynaptic functions/neuroplasticity. Reduced expression of the myelin protein cyclic nucleotide phosphodiesterase, reflecting a reduction of oligodendrocytes, may further contribute to the observed brain atrophy. Remarkably, early intervention with recombinant human erythropoietin (EPO), a hematopoietic growth factor with multifaceted neuroprotective properties (intraperitoneal injection of 5000 IU/kg body weight every other day for 3 weeks), prevented all these neurodegenerative changes. To conclude, unilateral parietal lesion of juvenile mice induces a non‐ gliotic neurodegenerative process, susceptible to early EPO treatment. Although the detailed mechanisms remain to be defined, these profound EPO effects open new ways for prophylaxis and therapy of neuropsychiatric diseases, e.g. schizophrenia. © 2008 Wiley‐Liss, Inc.
Oct4 is expressed in human gliomas and promotes colony formation in glioma cells
Authors: Du Zhanhui , Jia Deyong , Liu Shangming , Wang Fuwu , Li Gang , Zhang Yanmin , Cao Xinmin , Ling Eng‐Ang , Hao Aijun 
Published: November 2008

AbstractThere is increasing evidence that self‐renewal capacity of cancer cells is critical for carcinogenesis; hence, it is vital to examine the expression and involvement of self‐renewal regulatory genes in these cells. Here, we reported that Oct4, a well‐known regulator of self‐renewal in embryonic stem cells, was highly expressed in human gliomas and glioma cell lines, and the expression levels were increased in parallel with increasing glioma grades. In in vitro cell cultures, Oct4 was only expressed in rat C6 glioma cells and rat neural stem cells but not in rat brain differentiated cells. Downregulation of Oct4 expression by RNA interference in C6 cells was associated with reduced cell proliferation and colony formation. Further analysis revealed that Oct4 could upregulate phosphorylation of Stat3 to promote tumor cell proliferation. Overexpression of Oct4 in C6 cells increased the expression of nestin but decreased the expression of GFAP suggesting that Oct4 might inhibit the differentiation of glioma cells. Our findings may provide further evidence for the stem cell theory of carcinogenesis. In contrast, the results might also imply that Oct4 contributes to the existence of undifferentiated cells in gliomas. © 2008 Wiley‐Liss, Inc.
Proinflammatory cytokines and HIV‐1 synergistically enhance CXCL10 expression in human astrocytes
Authors: Williams Rachel , Dhillon Navneet K. , Hegde Sonia T. , Yao Honghong , Peng Fuwang , Callen Shannon , Chebloune Yahia , Davis Randall L. , Buch Shilpa J. 
Published: November 2008

AbstractHIV encephalitis (HIVE), the pathologic correlate of HIV‐associated dementia (HAD) is characterized by astrogliosis, cytokine/chemokine dysregulation, and neuronal degeneration. Increasing evidence suggests that inflammation is actively involved in the pathogenesis of HAD. In fact, the severity of HAD/HIVE correlates more closely with the presence of activated glial cells than with the presence and amount of HIV‐infected cells in the brain. Astrocytes, the most numerous cell type within the brain, provide an important reservoir for the generation of inflammatory mediators, including interferon‐γ inducible peptide‐10 (CXCL10), a neurotoxin and a chemoattractant, implicated in the pathophysiology of HAD. Additionally, the proinflammatory cytokines, IFN‐γ and TNF‐α, are also markedly increased in CNS tissues during HIV‐1 infection. In this study, we hypothesized that the interplay of host cytokines and HIV‐1 could lead to enhanced expression of the toxic chemokine, CXCL10. Our findings demonstrate a synergistic induction of CXCL10 mRNA and protein in human astrocytes exposed to HIV‐1 and the proinflammatory cytokines. Signaling molecules, including JAK, STATs, MAPK (via activation of Erk1/2, AKT, and p38), and NF‐κB were identified as instrumental in the synergistic induction of CXCL10. Understanding the mechanisms involved in HIV‐1 and cytokine‐mediated up‐regulation of CXCL10 could aid in the development of therapeutic modalities for HAD. © 2008 Wiley‐Liss, Inc.
Photothrombosis ischemia stimulates a sustained astrocytic Ca2+ signaling in vivo
Authors: Ding Shinghua , Wang Tiannan , Cui Wenju , Haydon Philip G. 
Published: November 2008

AbstractAlthough there is significant information concerning the consequences of cerebral ischemia on neuronal function, relatively little is known about functional responses of astrocytes, the predominant glial‐cell type in the central nervous system. In this study, we asked whether focal ischemia would impact astrocytic Ca2+ signaling, a characteristic form of excitability in this cell type. In vivo Ca2+ imaging of cortical astrocytes was performed using two‐photon (2‐P) microscopy during the acute phase of photothrombosis‐induced ischemia initiated by green light illumination of circulating Rose Bengal. Although whisker evoked potentials were reduced by over 90% within minutes of photothrombosis, astrocytes in the ischemic core remained structurally intact for a few hours. In vivo Ca2+ imaging showed that an increase in transient Ca2+ signals in astrocytes within 20 min of ischemia. These Ca2+ signals were synchronized and propagated as waves amongst the glial network. Pharmacological manipulations demonstrated that these Ca2+ signals were dependent on activation of metabotropic glutamate receptor 5 (mGluR5) and metabotropic γ‐aminobutyric acid receptor (GABABR) but not by P2 purinergic receptor or A1 adenosine receptor. Selective inhibition of Ca2+ in astrocytes with BAPTA significantly reduced the infarct volume, demonstrating that the enhanced astrocytic Ca2+ signal contributes to neuronal damage presumably through Ca2+‐dependent release of glial glutamate. Because astrocytes offer multiple functions in close communication with neurons and vasculature, the ischemia‐induced increase in astrocytic Ca2+ signaling may represent an initial attempt for these cells to communicate with neurons or provide feed back regulation to the vasculature. © 2008 Wiley‐Liss, Inc.
Category‐specificity in the human medial temporal lobe cortex
Authors: Litman L. , Awipi T. , Davachi L. 
Published: November 2008

AbstractThe medial temporal lobe cortex (MTLC) occupies a pivotal position at the interface between neocortical association areas and the hippocampus. It has been suggested that the MTLC contains functionally distinct regions, with perirhinal cortex (PRc) preferentially supporting object processing and posterior parahippocampal cortex (PHc) preferentially supporting encoding of spatial information. Measuring differential BOLD responsiveness to objects, scenes, and other stimulus categories, we find a double dissociation between an anterior PRc response to objects and a posterior PHc response to scene stimuli. Furthermore, an anatomical ROI based approach was undertaken in an effort to understand the response profile underlying this double dissociation. We did not see any evidence for a sharp border between putatively distinct scene‐preferential and object‐preferential MTLC regions. Instead, scene‐preferential responsiveness was noted to drop off in a graded, linear fashion in successively anterior MTLC regions until object‐preferential responsiveness emerged in anterior PRc, although objects produced above baseline responses across the anterior–posterior extent of the parahippocampal gyrus. Other stimulus categories, such as faces and words, led to above baseline activation in either a few confined regions (faces) or none at all (words). Thus, what differentiated regions along the parahippocampal gryus was the relative response to objects and scenes, not simply above baseline responses to either category. This pattern raises the possibility that posterior PHc, and anterior PRc are situated at the ends of a single organizational continuum supported by the entire length of MTLC. © 2008 Wiley‐Liss, Inc.
Body weight and incidence of breast cancer defined by estrogen and progesterone receptor status—A meta‐analysis
Authors: Suzuki Reiko , Orsini Nicola , Saji Shigehira , Key Timothy J. , Wolk Alicja 
Published: November 2008

AbstractEpidemiological evidence indicates that the association between body weight and breast cancer risk may differ across menopausal status as well as the estrogen receptor (ER) and progesterone receptor (PR) tumor status. To date, no meta‐analysis has been conducted to assess the association between body weight and ER/PR defined breast cancer risk, taking into account menopausal status and study design. We searched MEDLINE for relevant studies published from January 1, 1970 through December 31, 2007. Summarized risk estimates with 95% confidence intervals (CIs) were calculated using a random‐effects model. The summarized results of 9 cohorts and 22 case‐control studies comparing the highest versus the reference categories of relative body weight showed that the risk for ER+PR+ tumors was 20% lower (95% CI = −30% to −8%) among premenopausal (2,643 cases) and 82% higher (95% CI = 55–114%) among postmenopausal (5,469 cases) women. The dose‐response meta‐analysis of ER+PR+ tumors showed that each 5‐unit increase in body mass index (BMI, kg/m2) was associated with a 33% increased risk among postmenopausal women (95% CI = 20–48%) and 10% decreased risk among premenopausal women (95% CI = −18% to −1%). No associations were observed for ER−PR− or ER+PR− tumors. For discordant tumors ER+PR− (pre) and ER−PR+ (pre/post) the number of cases were too small (<200) to interpret results. The relation between body weight and breast cancer risk is critically dependent on the tumor's ER/PR status and the woman's menopausal status. Body weight control is the effective strategy for preventing ER+PR+ tumors after menopause. © 2008 Wiley‐Liss, Inc.
Electron beam‐melted, free‐form‐fabricated titanium alloy implants: Material surface characterization and early bone response in rabbits
Authors: Thomsen Peter , Malmström Johan , Emanuelsson Lena , René Magnus , Snis Anders 
Published: November 2008

AbstractTitanium‐6aluminum‐4vanadium implants (Ti6Al4V) were prepared by free‐form‐fabrication (FFF) and were used either as produced or after machining and compared with wrought machined Ti6Al4V. Auger electron spectroscopy (AES), depth profiles, and interferometry were used to analyze the surface properties. The tissue response after 6‐weeks in rabbit femur and tibia was evaluated using light microscopy and histomorphometry. The results revealed that the bulk chemical and mechanical properties of the reference material and the electron beam‐melted (EBM) material were within the ASTM F136 specifications. The as‐produced EBM Ti6Al4V implants had increased surface roughness, thicker surface oxide and, with the exception of a higher content of Fe, a similar surface chemical composition compared with machined EBM Ti6Al4V and machined, wrought Ti6Al4V implants. The two latter implants did not differ with respect to surface properties. The general tissue response was similar for all three implant types. Histomorphometry revealed a high degree of bone‐to‐implant contact (no statistically significant differences) for all the three implant types. The present results show that the surface properties of EBM Ti6Al4V display biological short‐term behavior in bone equal to that of conventional wrought titanium alloy. The opportunity to engineer geometric properties provides new and additional benefits which justify further studies. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
A keratin biomaterial gel hemostat derived from human hair: Evaluation in a rabbit model of lethal liver injury
Authors: Aboushwareb Tamer , Eberli Daniel , Ward Catherine , Broda Christopher , Holcomb John , Atala Anthony , Van Dyke Mark 
Published: November 2008

AbstractEffective hemostatic dressings that are compatible with tissues are needed. Keratins are a class of biomaterials that can be derived by extraction of proteins from human hair. We have recently discovered that keratin biomaterials have hemostatic characteristics and hypothesize that a keratin hydrogel having the ability to absorb fluid and bind cells may be an effective hemostat. The goal of this study was to test a keratin hydrogel and evaluate it compared to current hemostats. Thirty‐two New Zealand white rabbits received a lethal liver injury. Eight animals each were assigned to negative control, QuickClot®, HemCon® bandage, and keratin treatment groups. Vital stats and other data were recorded during surgery and all surviving animals were sacrificed after 72 h. Histology was conducted on all surviving animals. Twenty‐four‐hour survival rates were 0%, 62.5%, 62.5%, and 75% for the negative control, QuickClot, HemCon, and keratin groups, respectively. Other outcomes included blood loss, mean arterial pressure, heart rate, shock index, and liver histology. All of the hemostats were statistically better than the negative control group at late operative time points. The keratin group consistently performed as well as, or better than, the commercial hemostats. Histology showed an interesting healing response at the hemostat‐liver interface in the keratin group. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Evaluation of sequentially crosslinked ultra‐high molecular weight polyethylene
Authors: Morrison M. L. , Jani S. 
Published: November 2008

AbstractThis study was undertaken to investigate the effect of crosslinking ultra‐high molecular weight polyethylene (UHMWPE) in a sequential manner to the final desired dose and to compare the results to single‐dose crosslinking. To verify these results, an explanted, commercially available, sequentially crosslinked component was characterized. Finally, additional tensile testing was conducted to determine if tensile‐sample thickness has a significant effect on the mechanical properties of UHMWPE. Based upon this well‐controlled study with the same starting material, there is no apparent benefit of sequential crosslinking over crosslinking by single dose in any of the mechanical, thermophysical, physical, or oxidative properties evaluated in this study. In contrast, the soak temperature of the postirradiation heat treatment was more influential and exhibited statistically significant effects on the stability, structure, and properties of the resultant material. Compared to virgin material, crosslinking always resulted in decreases in tensile strength, elongation, and impact strength. These results were confirmed by characterization of a retrieved, sequentially crosslinked (X3™) cup. All of the metrics derived for the retrieved cup were virtually identical to the sequential‐ and single‐dose‐crosslinked materials produced in this study. Examination of the effect of tensile‐sample thickness demonstrated that there are significant effects on the resultant properties. In particular, the ultimate tensile strength of UHMWPE can be elevated by conducting tensile tests with thin specimens. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009