bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracellular interactome of the FGF receptor–ligand system: Complexities and the relative simplicity of the worm
Authors: Polanska Urszula M. , Fernig David G. , Kinnunen Tarja
Published: November 2008

Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate a multitude of biological functions in embryonic development and in adult. A major question is how does one family of growth factors and their receptors control such a variety of functions? Classically, specificity was thought to be imparted by alternative splicing of the FGFRs, resulting in isoforms that bind specifically to a subset of the FGFs, and by different saccharide sequences in the heparan sulfate proteoglycan (HSPG) co‐receptor. A growing number of noncanonical co‐receptors such as integrins and neural cell adhesion molecule (NCAM) are now recognized as imparting additional complexity to classic FGFR signaling. This review will discuss the noncanonical FGFR ligands and speculate on the possibility that they provide additional and alternative means to determining the functional specificity of FGFR signaling. We will also discuss how invertebrate models such as C. elegans may advance our understanding of noncanonical FGFR signaling. Developmental Dynamics 238:277–293, 2009. © 2008 Wiley‐Liss, Inc.
Cerberus functions as a BMP agonist to synergistically induce nodal expression during left–right axis determination in the chick embryo
Authors: Yu Xueyan , He Fenglei , Zhang Tao , Espinoza‐Lewis Ramón A. , Lin Lisong , Yang Jing , Chen Yiping
Published: November 2008

Left‐sided expression of Nodal in the lateral plate mesoderm (LPM) during early embryogenesis is a crucial step in establishing the left–right (L–R) axis in vertebrates. In the chick, it was suggested that chick Cerberus (cCer), a Cerberus/Dan family member, induces Nodal expression by antagonizing bone morphogenetic protein (BMP) activity in the left LPM. In contrast, it has also been shown that BMPs positively regulate Nodal expression in the left LPM in the chick embryo. Thus, it is still unclear how the bilaterally expressed BMPs induce Nodal expression only in the left LPM. In this study, we demonstrate that BMP signaling is necessary and sufficient for the induction of Nodal expression in the chick LPM where the type I BMP receptor‐IB (BMPR‐IB) likely mediates this induction. Tissue grafting experiments indicate the existence of a Nodal inductive factor in the left LPM rather than the presence of a Nodal inhibitory factor in the right LPM. We demonstrate that cCer functions as a BMP agonist instead of antagonist, being able to enhance BMP signaling in cell culture. This conclusion is further supported by the immunoprecipitation assays that provide convincing biochemical evidence for a direct interaction between cCer and BMP receptor. Because cCer is expressed restrictedly in the left LPM, BMPs and cCer appear to act synergistically to activate Nodal expression in the left LPM in the chick. Developmental Dynamics 237:3613–3623, 2008. © 2008 Wiley‐Liss, Inc.
Ocular coloboma and dorsoventral neuroretinal patterning defects in Lrp6 mutant eyes
Authors: Zhou Cheng‐Ji , Molotkov Andrei , Song Lanying , Li Yunhong , Pleasure David E. , Pleasure Samuel J. , Wang Ya‐Zhou
Published: November 2008

Coloboma, an ocular birth defect seen in humans and other species, is caused by incomplete closure of the optic fissure. Here, we demonstrate that genetic deletion of Lrp6, a bottleneck coreceptor in the canonical Wnt signaling pathway, results in ocular coloboma and neuroretinal patterning defects in mice. The expression of ventral neuroretinal patterning gene Vax2 was conserved but with dorsally shifted expression domains; however, the dorsal neuroretinal patterning gene Tbx5 was lost in the Lrp6‐mutant eyes at embryonic day 10.5. Both Bmp4 and phosphorylated Smad 1/5/8 were also significantly attenuated in the dorsal neuroretina. In addition, the retinoic acid synthesizing enzymes Raldh1 and Raldh3 were significantly changed in the mutant eyes. Our findings suggest that defective retinal patterning causes coloboma in the Lrp6‐deficient mice, and that canonical Wnt signaling plays a primary role in dorsal neuroretinal patterning and related morphogenetic movements by regulation of both Bmp and retinoic acid signaling pathways. Developmental Dynamics 237:3681–3689, 2008. © 2008 Wiley‐Liss, Inc.
Initiation and propagation of posterior to anterior (PA) waves in zebrafish left–right development
Authors: Wang Xinghao , Yost H. Joseph
Published: November 2008

One of the most highly conserved steps in left–right patterning is asymmetric gene expression in lateral plate mesoderm (LPM). Here, we quantitatively describe the timing of the posterior to anterior (PA) wave‐like propagation of zebrafish southpaw (Nodal) and pitx2 in LPM and lefty1 in the midline. By altering the timing of the PA wave, we provide evidence that the PA wave in the LPM instructs brain asymmetry. We find that initiation of pitx2 in LPM and lefty1 in midline depends on Southpaw, and that casanova (sox32) and two Nodal inhibitors, lefty1 and charon, have distinct roles upstream of PA wave initiation. Surprisingly, Casanova, endoderm and Kupffer's Vesicle are not required for normal timing of southpaw initiation and PA propagation. In contrast, lefty1 morphants display precocious asymmetric initiation of southpaw with an intrinsic left‐hand orientation, whereas charon morphants have premature initiation without LR orientation, indicating distinct roles for these Nodal antagonists. Developmental Dynamics 237:3640–3647, 2008. © 2008 Wiley‐Liss, Inc.
Stretching the limits: Stem cells in regeneration science
Authors: Stocum David L. , Zupanc Günther K.H.
Published: November 2008

The focus of regenerative medicine is rebuilding damaged tissues by cell transplantation or implantation of bioartificial tissues. In either case, therapies focus on adult stem cells (ASCs) and embryonic stem cells (ESCs) as cell sources. Here we review four topics based on these two cell sources. The first compares the current performance of ASCs and ESCs as cell transplant therapies and the drawbacks of each. The second explores somatic cell nuclear transfer (SCNT) as a method to derive ESCs that will not be immunorejected. The third topic explores how SCNT and ESC research has led to the ability to derive pluripotent ESCs by the dedifferentiation of adult somatic cells. Lastly, we discuss how research on activation of intrinsic adult stem cells and on somatic cell dedifferentiation can evolve regenerative medicine from a platform consisting of cell transplantation to one that includes the chemical induction of regeneration from the body's own cells at the site of injury. Developmental Dynamics 237:3648–3671, 2008. © 2008 Wiley‐Liss, Inc.
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

Members 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

A 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

The 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

In 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

Novel 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

A 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

In 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

A 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

There 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

HIV 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

Although 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

The 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

Epidemiological 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

Titanium‐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

Effective 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

This 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
Bioactive glass and autogenous bone as bone graft substitutes in benign bone tumors
Authors: Lindfors Nina C. , Heikkilä Jouni T. , Koski Ilona , Mattila Kimmo , Aho Allan J.
Published: November 2008

In a prospective randomized study, 25 patients with benign bone tumors were surgically treated with either bioactive glass S53P4 (BG) or autogenous bone (AB) as bone graft material. X‐rays were taken preoperatively and postoperatively at 2 weeks and at 3, 8, 12, 18, 24, and 36 months. In addition, for most of the patients, CT scans were performed at the same time‐points. No infections or material‐related adverse reactions occurred in any patient. The filled cavity was replaced faster by new bone in the AB group than in the BG group (p = 0.0001). However, at 36 months, no statistical difference in cavity volume between the two groups was observed on X‐rays (p = 0.7881) or on CT scans (p = 0.9117). In the BG group at 3 years, the filled cavity appeared, however, dense on X‐rays, and glass granules on CT scans were observed. During the follow‐up period, the cortical thickness seemed to increase more in the BG group than in the AB group (p < 0.0001). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Conformational preferences of N‐methoxycarbonyl proline dipeptide
Authors: Kang Young Kee , Kang Nam Sook
Published: November 2008

The conformational study on N‐methoxycarbonyl‐L‐proline‐N′‐methylamide (Moc‐Pro‐NHMe, prolylcarbamate) is carried out using ab initio HF and density functional B3LYP methods with the self‐consistent reaction field method in the gas phase and in solution (chloroform, acetonitrile, and water). The replacement of the N‐acetyl group by the N‐methoxycarbonyl group results in the changes in conformational preferences, populations for backbone and prolyl puckering, and barriers to cis‐trans isomerization of the prolyl residue in the gas phase and in solution, although there are small changes in the geometry of the prolyl peptide bond and the torsion angles of backbone and prolyl ring. The cis population increases with the increase of solvent polarity, as found for Ac‐Pro‐NHMe (prolylamide), but it is amplified by 9% in the gas phase and about 17% in solution for prolylcarbamate compared with those for prolylamide. It is found that the cis‐trans isomerization for prolylcarbamate proceeds through the clockwise rotation with ω′ ≈ +120° about the prolyl peptide bond in the gas phase and in solution, as found for prolylamide. However, the rotational barriers to the cis‐trans isomerization for prolylcarbamate are calculated to be 3.7–4.7 kcal/mol lower than those of prolylamide in the gas phase and in solution, and are found to be less sensitive to the solvent polarity. The calculated rotational barriers for prolylcarbamate in chloroform and water are in good agreement with the observed values. The shorter hydrogen‐bond distance between the prolyl nitrogen and the amide H (HNHMe) of the NHMe group, the decrease in electron overlap of the prolyl CN bond, and the favorable electrostatic interaction between the ester oxygen and the amide HNHMe for the transition state seem to play a role in lowering the rotational barrier of prolylcarbamate. The smaller molecular dipole moments of the ground‐ and transition‐state structures for prolylcarbamate in the gas phase and in solution seem to be one of factors to make the rotational barrier less sensitive to the solvent polarity. As the solvent polarity increases (i.e., from the gas phase to chloroform to acetonitrile), the value of ΔH decreases and the magnitude of ΔS increases for prolylcarbamate, which results in a nearly constant value of the rotational barrier. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Ab initio description of photoabsorption and electron transfer in a doubly‐linked porphyrin‐fullerene dyad
Authors: Cramariuc Oana , Hukka Terttu I. , Rantala Tapio T. , Lemmetyinen Helge
Published: November 2008

Structure, photoabsorption and excited states of two representative conformations obtained from molecular dynamics (MD) simulations of a doubly‐linked porphyrin‐fullerene dyad DHD6ee are studied by using both DFT and wavefunction based methods. Charge transfer from the donor (porphyrin) to the acceptor (fullerene) and the relaxation of the excited state are of special interest. The results obtained with LDA, GGA, and hybrid functionals (SVWN, PBE, and B3LYP, respectively) are analyzed with emphasis on the performance of used functionals as well as from the point of view of their comparison with wavefunction based methods (CCS, CIS(D), and CC2). Characteristics of the MD structures are retained in DFT optimization. The relative orientation of porphyrin and fullerene is significantly influencing the MO energies, the charge transfer (CT) in the ground state of the dyad and the excitation of ground state CT complex (g‐CTC). At the same time, the excitation to the locally excited state of porphyrin is only little influenced by the orientation or cc distance. TD‐DFT underestimates the excitation energy of the CT state, however for some cases (with relatively short donor‐acceptor separations), the use of a hybrid functional like B3LYP alleviates the problem. Wavefunction based methods and CC2 in particular appear to overestimate the CT excitation energies but the inclusion of proper solvation models can significantly improve the results. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Topology‐based models and NMR structures in protein folding simulations
Authors: Rey‐Stolle M. Fernanda , Enciso Marta , Rey Antonio
Published: November 2008

Topology‐based interaction potentials are simplified models that use the native contacts in the folded structure of a protein to define an energetically unfrustrated folding funnel. They have been widely used to analyze the folding transition and pathways of different proteins through computer simulations. Obviously, they need a reliable, experimentally determined folded structure to define the model interactions. In structures elucidated through NMR spectroscopy, a complex treatment of the raw experimental data usually provides a series of models, a set of different conformations compatible with the available experimental data. Here, we use an efficient coarse‐grained simulation technique to independently consider the contact maps from every different NMR model in a protein whose structure has been resolved by the use of NMR spectroscopy. For λ‐Cro repressor, a homodimeric protein, we have analyzed its folding characteristics with a topology‐based model. We have focused on the competition between the folding of the individual chains and their binding to form the final quaternary structure. From 20 different NMR models, we find a predominant three‐state folding behavior, in agreement with experimental data on the folding pathway for this protein. Individual NMR models, however, show distinct characteristics, which are analyzed both at the level of the interplay between tertiary/quaternary structure formation and also regarding the thermal stability of the tertiary structure of every individual chain. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Investigations of an OH · · · S hydrogen bond via Car‐Parrinello and path integral molecular dynamics
Authors: Jezierska Aneta , Panek Jarosław J.
Published: November 2008

The presence of intramolecular hydrogen bonds influences the binding energy, tautomeric equilibrium, and spectroscopic properties of various classes of organic molecules. This article discusses the OH · · · S bridge, one of the less commonly investigated types of intramolecular interactions. 3‐mercapto‐1,3‐diphenylprop‐2‐en‐1‐one was considered as the model structure. This compound exhibits photochromic properties. Car‐Parrinello molecular dynamics (CPMD) was applied to investigate the spectroscopic and molecular properties of this compound in the gas phase and in the solid state. The second part of the study is devoted to the effects of the quantization of nuclear motions, with special attention to the OH · · · S moiety. Path integral molecular dynamics (PIMD) of the molecular crystal of 3‐mercapto‐1,3‐diphenylprop‐2‐en‐1‐one was carried out for this purpose. The employment of this fully quantum mechanical technique enables one to study, in a time‐averaged sense, the zero‐point motion important for flat potential energy surfaces. Finally, the potentials of mean force (Pmfs) were calculated from the CPMD and PIMD data obtained for the solid‐state calculations. The effect of including quantum nuclear motion was investigated. In the studied compound, quantum effects shortened the H‐bridge and provided a better description of the free energy minimum. The computational results place this uncommon intramolecular H‐bonding among the class of strong hydrogen bonds with large red shifts of OH stretching modes, which correspond well with previously presented experimental data in the literature concerning this structure. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Metastasis and AKT activation
Authors: Sheng Shijie , Qiao Meng , Pardee Arthur B.
Published: November 2008

Metastasis, responsible for 90% of cancer patient deaths, is an inefficient process because many tumor cells die. The survival of metastatic tumor cells should be considered as a critical therapeutic target. This review provides a new perspective regarding the role of AKT in tumor survival, and the rationale to target AKT in anti‐metastasis therapies. J. Cell. Physiol. 218: 451–454, 2009. © 2008 Wiley‐Liss, Inc.
Glycosaminoglycan composition changes with MG‐63 osteosarcoma osteogenesis in vitro and induces human mesenchymal stem cell aggregation
Authors: Kumarasuriyar A. , Murali S. , Nurcombe V. , Cool S.M.
Published: November 2008

Osteogenic differentiation is coordinated by the exposure of cells to temporal changes in a combination of growth factors and elements within the extracellular matrix (ECM). Many of the key proteins that drive these changes share the property of being dependent on ECM glycosaminoglycans (GAGs) for their activity. Here, we examined whether GAGs isolated from proliferating, differentiating and mineralizing MG‐63 osteosarcoma cells differed in their physical properties, and thus in their capacities to coordinate the osteogenic cascade both in human MG‐63 osteosarcoma cells and primary human mesenchymal stem cells (hMSCs). Our results show that the size distribution of GAGs, the expression of GAG‐carrying proteoglycan cores and the expression of enzymes involved in their modification systematically change as MG‐63 cells mature in culture. When dosed back onto cells exogenously in soluble form, GAGs regulated MG‐63 survival and growth in a dose‐dependent manner, but not differentiation in either cell type. In contrast, hMSCs aggregated into distinct colonies when grown on GAG‐coated substrates, while MG‐63 cells did not. Heparin‐coated substrates improved hMSC viability without inducing aggregation. These results suggest a complex role for GAGs in coordinating the emergence of the osteoblast phenotype, and provide further evidence for the use of heparans in bone tissue repair applications. J. Cell. Physiol. 218: 501–511, 2009. © 2008 Wiley‐Liss, Inc.
Evidence that leptin through STAT and CREB signaling enhances cyclin D1 expression and promotes human endometrial cancer proliferation
Authors: Catalano Stefania , Giordano Cinzia , Rizza Pietro , Gu Guowei , Barone Ines , Bonofiglio Daniela , Giordano Francesca , Malivindi Rocco , Gaccione Donatella , Lanzino Marilena , De Amicis Francesca , Andò Sebastiano
Published: November 2008

Obesity is a risk factor for endometrial cancer in pre‐ and post‐menopausal women. Leptin, an adipocyte‐derived hormone, in addition to the control weight homeostasis, is implicated in multiple biological actions. A recent study demonstrated that leptin promotes endometrial cancer growth and invasiveness through STAT/MAPK and Akt pathways, but the molecular mechanism involved in such processes still needs to be elucidated. In an attempt to understand the role of leptin in regulating endometrial cancer cells proliferation, we have demonstrated that leptin treatment reduced the numbers of cells in G0/G1‐phase while increased cell population in S‐phase. This effect is associated with an up‐regulation of cyclin D1 together with a down‐regulation of cyclin‐dependent kinase inhibitor p21WAF1/Cip1. Mutagenesis studies, eletrophoretic mobility shift, and chromatin immunoprecipitation analysis revealed that signal transducers and activators of transcription 3 (STAT3) and cyclic AMP‐responsive element (CRE) binding protein motifs, within cyclin D1 promoter, were required for leptin‐induced cyclin D1 expression in Ishikawa endometrial cancer cells. Silencing of STAT3 and CREB gene expression by RNA interference reversed the up‐regulatory effect of leptin on cyclin D1 expression and cells proliferation. These results support the hypothesis that STAT3 and CREB play an important role in leptin signaling pathway that leads to the proliferation of Ishikawa cells, thus establishing a direct association between obesity and endometrial tumorogenesis. J. Cell. Physiol. 218: 490–500, 2009. © 2008 Wiley‐Liss, Inc.
Analysis of gene expression in gecko digital adhesive pads indicates significant production of cysteine‐ and glycine‐rich beta‐keratins
Authors: Hallahan David L. , Keiper‐Hrynko Natalie M. , Shang Tanya Q. , Ganzke Thaya S. , Toni Mattia , Dalla Valle Luisa , Alibardi Lorenzo
Published: November 2008

Microscopic bristles (setae) present on digital pads permit the adhesion and climbing of geckos. Keratins of setae of the lizard Gekko gecko (Tokay gecko) were analyzed by the isolation of expressed mRNAs and by the generation of an EST library. Of the 510 sequences determined, 268 (52.9%) were unique. Of these, 14 appeared to encode alpha‐ and 111 beta‐keratins. Within the beta‐keratins, we identified five groups based on nucleotide sequence comparisons. Of these, one contained the bulk of beta‐keratins, with 103 EST members. The mRNAs within this major group, together with two singlets, encoded cysteine–proline–serine‐rich proteins of 10–14 kDa (Ge‐cprp). One of the smaller groups of transcripts encoded slightly larger glycine–proline–serine‐rich proteins, of 14–19 kDa (Ge‐gprp). The remaining group consisted of smaller (9 kDa) serine–tyrosine‐rich beta‐keratins (Ge‐strp). Thus three classes could be distinguished by amino acid sequence alignment. Exact matches for some of the peptide sequences obtained from setal proteins by ms/ms sequencing occur within several of these clones. Most of the beta‐keratins were basic and contained a core‐box region of two beta‐strand sequences, with high homology to core‐boxes present in avian scale and feather beta‐keratins. Core‐boxes are beta‐folded regions that are likely responsible for polymerization into the beta‐keratin filaments. The two deduced alpha‐keratins of 52.7 kDa are both acidic, and contain the typical central rod region with some homology to mammalian and avian alpha‐keratins, with variable N‐ and C‐terminal regions. Basic beta‐keratins and acidic alpha‐keratins may interact electrostatically to form the resistant corneous material of setae. J. Exp. Zool. (Mol. Dev. Evol.) 312B:58–73, 2009. © 2008 Wiley‐Liss, Inc.
Remodeling of fracture callus in mice is consistent with mechanical loading and bone remodeling theory
Authors: Isaksson Hanna , Gröngröft Ina , Wilson Wouter , van Donkelaar Corrinus C. , van Rietbergen Bert , Tami Andrea , Huiskes Rik , Ito Keita
Published: November 2008

During the remodeling phase of fracture healing in mice, the callus gradually transforms into a double cortex, which thereafter merges into one cortex. In large animals, a double cortex normally does not form. We investigated whether these patterns of remodeling of the fracture callus in mice can be explained by mechanical loading. Morphologies of fractures after 21, 28, and 42 days of healing were determined from an in vivo mid‐diaphyseal femoral osteotomy healing experiment in mice. Bone density distributions from microCT at 21 days were converted into adaptive finite element models. To assess the effect of loading mode on bone remodeling, a well‐established remodeling algorithm was used to examine the effect of axial force or bending moment on bone structure. All simulations predicted that under axial loading, the callus remodeled to form a single cortex. When a bending moment was applied, dual concentric cortices developed in all simulations, corresponding well to the progression of remodeling observed experimentally and resulting in quantitatively comparable callus areas of woven and lamellar bone. Effects of biological differences between species or other reasons cannot be excluded, but this study demonstrates how a difference in loading mode could explain the differences between the remodeling phase in small rodents and larger mammals. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 664–672, 2009