bluuebunny/crossref_metadata_2025 huggingface dataset:
Talin2 is induced during striated muscle differentiation and is targeted to stable adhesion complexes in mature muscle
Authors: Senetar Melissa A. , Moncman Carole L. , McCann Richard O.
Published: December 2006

The cytoskeletal protein talin serves as an essential link between integrins and the actin cytoskeleton in several similar, but functionally distinct, adhesion complexes, including focal adhesions, costameres, and intercalated disks. Vertebrates contain two talin genes, TLN1 and TLN2, but the different roles of Talin1 and Talin2 in cell adhesion are unclear. In this report we have analyzed Talin1 and Talin2 in striated muscle. Using isoform‐specific antibodies, we found that Talin2 is highly expressed in mature striated muscle. Using mouse C2C12 cells and primary human skeletal muscle myoblasts as models of muscle differentiation, we show that Talin1 is expressed in undifferentiated myoblasts and that Talin2 expression is upregulated during muscle differentiation at both the mRNA and protein levels. We have also identified regulatory sequences that may be responsible for the differential expression of Talin1 and Talin2. Using GFP‐tagged Talin1 and Talin2 constructs, we found that GFP‐Talin1 targets to focal adhesions while GFP‐Talin2 targets to abnormally large adhesions in myoblasts. We also found that ectopic expression of Talin2 in myoblasts, which do not contain appreciable levels of Talin2, dysregulates the actin cytoskeleton. Finally we demonstrate that Talin2, but not Talin1, localizes to costameres and intercalated disks, which are stable adhesions required for the assembly of mature striated muscle. Our results suggest that Talin1 is the primary link between integrins and actin in dynamic focal adhesions in undifferentiated, motile cells, but that Talin2 may serve as the link between integrins and the sarcomeric cytoskeletonin stable adhesion complexes in mature striated muscle. Cell Motil. Cytoskeleton 2007. © 2006 Wiley‐Liss, Inc.
Tumor‐derived factors impaired motility and immune functions of dendritic cells through derangement of biophysical characteristics and reorganization of cytoskeleton
Authors: Zeng Zhu , Xu Xiaofeng , Zhang Yingyu , Xing Junjie , Long Jinhua , Gu Li , Wang Xianwei , Sun Dagong , Ka Weibo , Yao Weijuan , Wen Zongyao , Chien Shu
Published: December 2006

The generation and progress of tumors are accompanied with a marked suppression of human immune system. To explore the mechanisms by which tumors escape from immune recognition, we studied the influences of tumor microenvironment on differentiation of dendritic cells (DCs), which play an important role in tumor immunology, by biophysical and immunological methods. It was found that the cytokines derived from tumors caused an increase in osmotic fragility and a decrease in membrane fluidity of DCs, disordering and elevated expression levels of cytoskeleton, and changes of the gene transcriptional levels and energy status of the cells. Moreover, IL‐12 production and the expression levels of some surface‐marker molecules were also suppressed. These changes led to impaired capabilities of antigen uptake, cell motility and naïve T cell activation; the abnormal biophysical characteristics of DCs may be one aspect of the immune escape mechanism of tumor. These results provide insights into the importance of the reconstruction of tumor microenvironment for immunotherapy based on the anti‐cancer activities of DCs. Cell Motil. Cytoskeleton 2007. © 2006 Wiley‐Liss, Inc.
Reconstitution in vitro of MSP‐based filopodium extension in nematode sperm
Authors: Miao Long , Yi Kexi , Mackey Joy M. , Roberts Thomas M.
Published: December 2006

The major sperm protein (MSP) motility system in nematode sperm is best known for propelling the movement of mature sperm, where it has taken over the role usually played by actin in amoeboid cell motility. However, MSP filaments also drive the extension of filopodia, transient organelles composed of a core bundle of MSP filaments, that form in the late in sperm development but are not found on crawling cells. We have reconstituted filopodial extension in vitro whereby thin bundles of MSP filaments, each enveloped by a membrane sheath at their growing end, elongated at rates up to 17 μm/min. These bundles often exceeded 500 μm in length but were comprised of filaments only 1 μm long. The reconstituted filopodia assembled in the same cell‐free sperm extracts that produced MSP fibers, robust meshworks of filaments that exhibit the same organization and dynamics as the lamellipodial filament system that propels sperm movement. The filopodia and fibers that assembled in vitro both had a membranous structure at their growing end, shared four MSP accessory proteins, and responded identically to agents that alter MSP‐based motility by modulating protein phosphorylation. However, filopodia grew three‐ to four‐fold faster than fibers. The reconstitution of filopodial extension shows that, like the actin cytoskeleton, MSP filaments can adopt two architectures, bundles and meshworks, each capable of pushing against membranes to generate protrusion. The reconstitution of both forms of motility in the same in vitro system provides a promising avenue for understanding how the forces for membrane protrusion are produced. Cell Motil. Cytoskeleton 2007. © 2006 Wiley‐Liss, Inc.
Alpha‐smooth muscle actin expression enhances cell traction force
Authors: Chen Jianxin , Li Hongxia , SundarRaj Nirmala , Wang James H.‐C.
Published: December 2006

Using an established corneal stromal cell differentiation model, we manipulated α‐smooth muscle actin (α‐SMA) protein expression levels in fibroblasts by treating them with TGF‐β1, bFGF, TGF‐β type I receptor inhibitor (SB‐431542), and siRNA against α‐SMA. The corresponding cell traction forces (CTFs) were determined by cell traction force microscopy. With all these treatments, we found that α‐SMA is not required for CTF induction, but its expression upregulates CTF. This upregulation involves the modification of stress fibers but does not appear to relate to non‐muscle myosin II expression or β‐actin expression. Moreover, there exists a linear relationship between α‐SMA protein expression level and CTF magnitude. Finally, CTFs were found to vary among a population of myofibroblasts, suggesting that α‐SMA protein expression levels of individual cells also vary. Cell Motil. Cytoskeleton 2007. © 2006 Wiley‐Liss, Inc.
Periosteal margin in soft‐tissue sarcoma
Authors: Lin Patrick P. , Pino Eduardo Diaz , Normand Anne N. , Deavers Michael T. , Cannon Christopher P. , Ballo Matthew T. , Pisters Peter W.T. , Pollock Raphael E. , Lewis Valerae O. , Zagars Gunar K. , Yasko Alan W.
Published: December 2006

BACKGROUND.

Soft‐tissue sarcomas frequently rest in contact with bone. The purpose of the study was to evaluate the risk of local recurrence for sarcomas adjacent to bone and to determine whether the periosteum provides an adequate margin of resection.

METHODS.

Fifty patients with soft‐tissue sarcomas abutting bone were treated at a single institution between 1990 and 2004. All patients had high‐grade, T2 (>5 cm), nonmetastatic disease in the lower extremity. Bone contact was verified by preoperative magnetic resonance imaging (MRI) and/or computed tomography (CT) scans. Forty‐three of 50 patients received preoperative radiation with a mean dose of 50 Gy. In 11 cases a composite resection of bone and soft tissue was performed. In 39 cases the excision involved only soft tissue.

RESULTS.

True bone invasion was verified by histopathologic examination in 3 of 50 cases (6%). Local recurrence in the soft tissues developed in 8 of 50 (16%) patients. In no case did the recurrence involve destruction of cortical bone or erosion into bone. The recurrent tumor resided against the region of previous bone contact in 1 of 8 cases. There was no statistically significant difference in local recurrence between patients who had composite bone resection and patients who had soft‐tissue resection only (P = .87).

CONCLUSIONS.

Relatively few sarcomas are able to penetrate cortical bone. Composite bone and soft‐tissue resections are indicated primarily for frank bone invasion. In the absence of this, the periosteum is an adequate surgical margin for sarcomas treated with wide excision and radiation. Cancer 2007;109:598–602. © 2006 American Cancer Society.
Testosterone replacement for hypogonadism after treatment of early prostate cancer with brachytherapy
Authors: Sarosdy Michael F.
Published: December 2006

BACKGROUND.

Controversy and a notable paucity of published clinical data best characterize the current knowledge of testosterone‐replacement therapy (TRT) for hypogonadism after treatment for early, localized prostate cancer. The objective of this study was to assess the risk of biochemical failure with TRT after treatment of early prostate cancer with permanent transperineal brachytherapy with or without external beam therapy in patients with low serum levels of testosterone and clinical symptoms of hypogonadism.

METHODS.

Patients who underwent prostate brachytherapy from 1996 to 2004 and received subsequent TRT for symptomatic hypogonadism were reviewed to detail cancer characteristics and treatment as well as pre‐ and post‐TRT serum testosterone and prostate‐specific antigen (PSA) values.

RESULTS.

Thirty‐one men received TRT after prostate brachytherapy for 0.5 to 8.5 years (median, 4.5 years), with a follow‐up that ranged from 1.5 years to 9.0 years (median, 5.0 years) postbrachytherapy. TRT was started from 0.5 years to 4.5 years (median, 2.0 years) after brachytherapy. Serum total testosterone levels ranged from 30 ng/dL to 255 ng/dL (median, 188 ng/dL) before TRT and rose to 365 ng/dL to 1373 ng/dL (median, 498 ng/dL) on TRT. Transient rises in PSA were observed in 1 patient. The most recent PSA level was <0.1 ng/mL in 23 patients (74.2%), <0.5 ng/mL in 30 patients (96.7%), and <1 ng/mL in 31 patients (100%). No patients stopped TRT because of cancer recurrence or documented cancer progression.

CONCLUSIONS.

For patients with low serum testosterone levels and symptoms of hypogonadism, TRT may be used with caution and close follow‐up after prostate brachytherapy. Cancer 2007;109:536–541. © 2006 American Cancer Society.
Cytoarchitectonic and chemoarchitectonic subdivisions of the perirhinal and parahippocampal cortices in macaque monkeys
Authors: Saleem Kadharbatcha S. , Price Joseph L. , Hashikawa Tsutomu
Published: December 2006

Although the perirhinal and parahippocampal cortices have been shown to be critically involved in memory processing, the boundaries and extent of these areas have been controversial. To produce a more objective and reproducible description, the architectonic boundaries and structure of the perirhinal (areas 35 and 36) and parahippocampal (areas TF and TH) cortices were analyzed in three macaque species, with four different staining methods [Nissl and immunohistochemistry for parvalbumin, nonphosphorylated neurofilaments (with SMI‐32), and the m2 muscarinic acetylcholine receptor]. We further correlated the architectonic boundary of the parahippocampal cortex with connections to and from different subregions of anterior area TE and with previously published connections with the prefrontal cortex and temporal pole (Kondo et al. [2005] J. Comp. Neurol. 493:479–509). Together, these data provided a clear delineation of the perirhinal and parahippocampal areas, although it differs from previous descriptions. In particular, we did not extend the perirhinal cortex into the temporal pole, and the lateral boundaries of areas 36 and TF with area TE were placed more medially than in other studies. The lateral boundary of area TF in Macaca fuscata was located more laterally than in Macaca fascicularis or Macaca mulatta, although there was no difference in architectonic structure. We recognized a caudal, granular part of the parahippocampal cortex that we termed “area TFO.” This area closely resembles the laterally adjacent area TE and the caudally adjacent area V4 but is clearly different from the more rostral area TF. These areas are likely to have distinct functions. J. Comp. Neurol. 500:973–1006, 2007. © 2006 Wiley‐Liss, Inc.
Phylogenetic preservation of α3 Na+,K+‐ATPase distribution in vertebrate peripheral nervous systems
Authors: Romanovsky Dmitry , Moseley Amy E. , Mrak Robert E. , Taylor Michael D. , Dobretsov Maxim
Published: December 2006

The α3 isoform of Na+,K+‐ATPase is uniquely expressed in afferent and efferent neurons innervating muscle spindles in the peripheral nervous system (PNS) of adult rats, but the distribution pattern of this isoform in other species has not been investigated. We compared expression of α3 Na+,K+‐ATPase in lumbar dorsal root ganglia (DRG), spinal roots, and skeletal muscle samples of amphibian (frog), reptilian (turtle), avian (pigeon and chicken), and mammalian (mouse and human) species. In all species studied, the α3 Na+,K+‐ATPase isoform was nonuniformly expressed in peripheral ganglia and nerves. In spinal ganglia, only 5–20% of neurons expressed this isoform, and, in avian and mammalian species, these α3 Na+,K+‐ATPase‐expressing neurons belonged to a subpopulation of large DRG neurons. In ventral root fibers of pigeons, mice, and humans, the α3 Na+,K+‐ATPase was abundantly expressed predominantly in small myelinated axons. In skeletal muscle samples from turtles, pigeons, mice, and humans, α3 Na+,K+‐ATPase was detected in intramuscular myelinated axons and in profiles of nerve terminals associated with the equatorial and polar regions of muscle spindle intrafusal fibers. These results show that the expression profiles for α3 Na+,K+‐ATPase in the peripheral nervous system of a wide variety of vertebrate species are similar to the profile of rats and suggest that stretch receptor‐associated expression of α3 Na+,K+‐ATPase is preserved through vertebrate evolution. J. Comp. Neurol. 500:1106–1116, 2007. © 2006 Wiley‐Liss, Inc.
Sobolev gradient preconditioning for image‐processing PDEs
Authors: Richardson W. B.
Published: December 2006

The article explores the relationship between Sobolev gradients and H−1 mixed methods for a variety of partial differential equations (PDEs) from image processing. A first‐order system least‐squares problem is used to introduce the method and compare the Euclidean with the Sobolev gradient. The standard two‐term decomposition of an image as f = u + v with u ∈ H1 and v ∈ L2 = H0 yields a second‐order linear PDE, while minimizing other Lp norms give nonlinear PDEs. Finally, a three‐term decomposition f = u + v + w with u ∈ H1, v ∈ H−1, w ∈ H0 requires the solution of a fourth‐order system with the biharmonic operator. Copyright © 2006 John Wiley & Sons, Ltd.
A MLPG(LBIE) numerical method for solving 2D incompressible and nearly incompressible elastostatic problems
Authors: Vavourakis V. , Polyzos D.
Published: December 2006

A new meshless local Petrov–Galerkin (MLPG) method, based on local boundary integral equation (LBIE) considerations, is proposed here for the solution of 2D, incompressible and nearly incompressible elastostatic problems. The method utilizes, for its meshless implementation, nodal points spread over the analysed domain and employs the moving least squares (MLS) approximation for the interpolation of the interior and boundary variables. On the local and global boundaries, traction vectors are treated in a way so that no derivatives of the utilized MLS shape functions are required. Both displacement and hydrostatic pressure, at all the considered nodal points, are evaluated with the aid of local integral representations valid for incompressible and nearly incompressible solids. Since displacements and stresses are treated as independed variables, the boundary conditions are imposed directly without any problem via the integrals defined on the global boundary of the analysed body. Singular and hypersingular integrals are evaluated directly with high accuracy through advanced integration techniques. Three numerical examples illustrate the proposed methodology and demonstrates its accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
From Cloudy to Transparent: Chain Rearrangement in Hydrogen‐Bonded Layer‐by‐Layer Assembled Films
Authors: Yang Shuguang , Zhang Yongjun , Zhang Xiaoyan , Guan Ying , Xu Jian , Zhang Xiaoli
Published: December 2006

The cloudiness of hydrogen‐bonded LBL films assembled from polyvinylpyrrolidone (PVPON) and poly(acrylic acid) (PAA) is studied in detail by two approaches: spectroscopy (Fabry–Pérot fringes) and microscopy (AFM). Fabrication parameters such as temperature, molecular weight, pH value, and rinsing time, have notable influences on film cloudiness. The buildup of the PVPON/PAA film is a two‐stage process of adsorption and chain rearrangement. Generally, adsorption is fast, while chain rearrangement is slow. The fast adsorption process traps defects, whereas the relatively slow chain‐rearrangement process can not heal the defects in time; therefore, the number of defects continuously increases as LBL assembly proceeds, and a cloudy, heterogeneous film is produced. However, the as‐prepared cloudy films become transparent and homogeneous on subsequent annealing in acidic water. UV/Vis spectroscopy and fluid AFM were applied to monitor this transition ex situ and in situ, respectively. It is found that increasing the annealing temperature accelerates the transition from cloudy to transparent, and the transition of the film made from higher molecular weight polymer is slower.
Heparan sulfate Ndst1 gene function variably regulates multiple signaling pathways during mouse development
Authors: Pallerla Srinivas R. , Pan Yi , Zhang Xin , Esko Jeffrey D. , Grobe Kay
Published: December 2006

Disruption of heparan sulfate (HS) synthesis in vertebrate development causes malformations that are composites of those caused by mutations of multiple HS binding growth factors and morphogens. We previously reported severe developmental defects of the forebrain and the skull in mutant mice bearing a targeted disruption of the heparan sulfate‐generating enzyme GlcNAc N‐deacetylase/GlcN N‐sulfotransferase 1 (Ndst1). Here, we further characterize the molecular mechanisms leading to frontonasal dysplasia in Ndst1 mutant embryos and describe additional malformations, including impaired spinal and cranial neural tube fusion and skeletal abnormalities. Of the numerous proteins that bind HS, we show that impaired fibroblast growth factor, Hedgehog, and Wnt function may contribute to some of these phenotypes. Our findings, therefore, suggest that defects in HS synthesis may contribute to multifactor types of congenital developmental defects in humans, including neural tube defects. Developmental Dynamics 236:556–563, 2007. © 2006 Wiley‐Liss, Inc.
Use, option and externality values: are contingent valuation studies in health care mis‐specified?
Authors: Smith Richard D.
Published: December 2006

A general population sample of Australian respondents completed a contingent valuation (CV) survey that asked them to value six scenarios. These varied according to whether the scenario was seeking to elicit: (i) use value; (ii) externality value; (iii) option value; or (iv) a combination. Results indicate that useplusexternality and/or option value was significantly greater than use value alone. As CV studies in health (care) overwhelmingly focus on use value alone – often implicitly through study design rather than explicitly – this raises the possibility of mis‐specification in CV research in health (care). The implications for CV in health (care) are considered. Copyright © 2006 John Wiley & Sons, Ltd.
Roles of learning and motivation in preference behavior: Mediation by entorhinal cortex, dorsal and ventral hippocampus
Authors: Stouffer Eric M. , White Norman M.
Published: December 2006

In the latent cue preference (LCP) task, water‐deprived rats alternately drink a salt solution in one distinctive compartment of a conditioned cue preference (CCP) apparatus and water in the other compartment over 8 days (training trials). They are then given a choice between the two compartments with no solutions present (preference test). Previous findings showed that this training procedure results in two parallel forms of learning: conditioning to water‐paired cues (a water‐CCP) and latent learning of an association between salt and salt‐paired compartment cues (a salt‐LCP). Experiment 1 examined these two types of learning in isolation. Results showed that expression of the salt‐LCP required salt deprivation during testing, but expression of the water‐CCP did not require a deprivation state during testing. Other results showed that salt‐LCP learning itself involves two distinct components: (1) the latent association among neutral cues in the salt‐paired compartment, and (2) motivational information about salt deprivation during testing. Previous findings also demonstrated roles for the dorsal hippocampus (DH), ventral hippocampus (VH), and entorhinal cortex (EC) in salt‐LCP learning. Experiment 2 examined the involvement of these structures during acquisition or expression of salt‐LCP learning. Rats with cannulas aimed at DH, VH, or EC were given infusions of muscimol, either before exposure to the salt‐paired, but not the water‐paired, compartment during training or before the preference test. Inactivation of the DH or EC impaired both acquisition and expression of the association between salt and salt‐paired compartment cues, while inactivation of the VH disrupted the influence of motivational information about salt deprivation required to express the salt‐LCP. These results suggest unique roles for the EC‐DH circuit and VH in salt‐LCP learning, as well as a functional dissociation between the DH and VH. © 2006 Wiley‐Liss, Inc.
Expression of embryonic tau protein isoforms persist during adult neurogenesis in the hippocampus
Authors: Bullmann Torsten , de Silva Rohan , Holzer Max , Mori Hiroshi , Arendt Thomas
Published: December 2006

Tau is a microtubule‐associated protein with a developmentally regulated expression of multiple isoforms. The neonatal isoform is devoid of two amino terminal inserts and contains only three instead of four microtubule‐binding repeats (0N/3R‐τ). We investigated the temporal expression pattern of 0N‐τ and 3R‐τ in the rat hippocampus. After the decline of 0N‐ and 3R‐τ immunoreactivity during the postnatal development both isoforms remain highly expressed in a few cells residing beneath the granule cell layer. Coexpression of the polysialylated neuronal cell adhesion molecule, doublecortin, and incorporated bromodeoxyuridine showed that these cells are proliferating progenitor cells. In contrast mature granule cells express the adult tau protein isoform containing one aminoterminal insert domain (1N‐τ). Therefore a shift in tau isoform expression takes place during adult neurogenesis, which might be related to migration, differentiation, and integration in the granule cell layer. A model for studying shifts in tau isoform expression in a defined subset of neurons might help to understand the etiology of tauopathies, when isoform composition is crucial for neurodegeneration, as in Pick's disease or FTDP‐17. © 2006 Wiley‐Liss, Inc.
On the use of partial probability weighted moments in the analysis of hydrological extremes
Authors: Moisello Ugo
Published: January 2007

The use of partial probability weighted moments (PPWM) for estimating hydrological extremes is compared to that of probability weighted moments (PWM). Firstly, estimates from at‐site data are considered. Two Monte Carlo analyses, conducted using continuous and empirical parent distributions (of peak discharge and daily rainfall annual maxima) and applying four different distributions (Gumbel, Fréchet, GEV and generalized Pareto), show that the estimates obtained from PPWMs are better than those obtained from PWMs if the parent distribution is unknown, as happens in practice. Secondly, the use of partial L‐moments (obtained from PPWMs) as diagnostic tools is considered. The theoretical partial L‐diagrams are compared with the experimental data. Five different distributions (exponential, Pareto, Gumbel, GEV and generalized Pareto) and 297 samples of peak discharge annual maxima are considered. Finally, the use of PPWMs with regional data is investigated. Three different kinds of regional analyses are considered. The first kind is the regression of quantile estimates on basin area. The study is conducted applying the GEV distribution to peak discharge annual maxima. The regressions obtained with PPWMs are slightly better than those obtained with PWMs. The second kind of regional analysis is the parametric one, of which four different models are considered. The congruence between local and regional estimates is examined, using peak discharge annual maxima. The congruence degree is sometimes higher for PPWMs, sometimes for PWMs. The third kind of regional analysis uses the index flood method. The study, conducted applying the GEV distribution to synthetic data from a lognormal joint distribution, shows that better estimates are obtained sometimes from PPWMs, sometimes from PWMs. All the results seem to indicate that using PPWMs can constitute a valid tool, provided that the influence of ouliers, of course higher with censored samples, is kept under control. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of structure, strength and cytocompatibility of a fibrin matrix supplemented either with tranexamic acid or aprotinin
Authors: Furst Walter , Banerjee Asmita , Redl Heinz
Published: December 2006

Fibrin sealants are used as hemostats, sealants, tissue adhesives, and as matrix for substances/cells in a number of surgical and tissue engineering procedures. Main characteristics of fibrin are high tensile strength, adhesive strength, biocompatibility, and resorption. A major adverse event would be premature fibrin lysis and recurrent bleeding. This must be prevented by fibrinolysis inhibitors. The most common fibrinolysis inhibitors used are aprotinin and tranexamic acid (t‐AMCA). Comparison of commercially available fibrin sealants utilizing aprotinin or t‐AMCA revealed a lower sealing efficacy in an in vivo lung resection model for a t‐AMCA containing product. Therefore, we compared the influence of t‐AMCA and aprotinin on structure, mechanical properties, and cytocompatibility of a fibrin matrix. In our experiments, we found that substitution of aprotinin with t‐AMCA reduced the tensile strength and formation of fibrin fibers and affected viability of a fibroblast cell‐line. In conclusion, t‐AMCA negatively affects physical and biological properties of fibrin relevant for clinical application as well as tissue regeneration. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2006
Human hepatoblast phenotype maintained by hyaluronan hydrogels
Authors: Turner William S. , Schmelzer Eva , McClelland Randall , Wauthier Eliane , Chen Weiliam , Reid Lola M.
Published: December 2006

Human hepatoblasts and hepatic stem cells, pluripotent hepatic progenitors that give rise to hepatocytes and biliary cells, were isolated from fetal livers and found to express hyaluronan receptors (CD44) in both the freshly isolated cells and after culture. This implicates an in vivo connection to hyaluronan (HA), an embryonic matrix component, as a candidate 3‐dimensional (3‐D) scaffold for hepatic progenitor cell expansion and/or differentiation. To assess HAs as scaffolds, hepatoblasts and hepatic stem cells were seeded into HA hydrogels with a serum‐free, hormonally defined medium tailored for expansion of hepatic progenitors. Cell aggregates formed within the HA hydrogels and remained viable, proliferative, and demonstrated a stable phenotype intermediate between that of hepatic stem cells and hepatoblasts throughout more than 4 weeks of culturing, with little evidence of lineage restriction towards either hepatocytic or biliary pathways. The phenotype consisted of stable co‐expression of both hepatocytic and biliary markers such as biliary‐specific cytokeratin, CK19, low levels of expression of albumin, and urea synthesis. HA hydrogels are ideal as 3‐D scaffolds for pluripotent hepatic progenitors and should be useful for generating cells to be used in bioartificial livers or tissue engineered liver grafts. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2006.
Mechanical and biocompatible influences of chitosan fiber and gelatin on calcium phosphate cement
Authors: Pan Zhaohui , Jiang Pingping , Fan Qingyu , Ma Baoan , Cai Heping
Published: December 2006

Calcium phosphate cement (CPC) is a widely used bone substitute in the clinic; however, the low strength of CPC limits its utilization. In this study, we investigated mechanical influences of chitosan fiber combined with gelatin on CPC, and examined the biocompatibility of the new composite with rat bone marrow stromal cells. Compared to the fiber impregnated in phosphate buffered saline (80.5 MPa), our study showed that tensile strength of chitosan fiber increased 106 and 114% with the impregnation of gelatin at the mass fraction 5 and 10%, although this increase was not statistically significant. It was demonstrated by Fourier transform infrared spectroscopy that the characteristic absorption bands of chitosan were changed with the addition of gelatin. The optimal flexural strength enhancement was obtained when CPC was reinforced with fiber at volume fraction of 30% and gelatin at mass fraction of 5% (maximum: 12.31 MPa). The fiber morphology was more compact when the chitosan fibers impregnated with gelatin at mass fraction of 5 or 10% than chitosan alone. The fracture analysis showed that the new CPC–chitosan fiber–gelatin composite presented many remnants of CPC adhered to fibers. Short minimum essential medium extract test showed no cell growth inhibition after the addition of the new composite. Rat bone marrow stromal cells retain the ability to spread and grow on the composite. Our studies demonstrated that the flexural strength is greatly increased by using CPC incorporated with proper ratio of CF and gelatin. More over, the new composite demonstrated biocompatibility in vitro. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2006.
BMP‐7 loaded microspheres as a new delivery system for the cultivation of human chondrocytes in a collagen type‐I gel
Authors: Gavénis Karsten , Klee Doris , Pereira‐Paz Rui M. , Walter Matthias von , Mollenhauer Jürgen , Schneider Ulrich , Schmidt‐Rohlfing Bernhard
Published: December 2006

In recent years, interest in chondrocyte cultures for transplantation has gained increasing attention. We investigated the use of PGLA microspheres as a new delivery system for BMP‐7 and the effects on human chondrocytes cultivated in a 3D collagen gel culture. In an in vitro study, human chondrocytes obtained from osteoarthritic knee joints were released, transferred into a collagen type‐I gel, and cultivated up to 14 days. In the treatment group PGLA microspheres loaded with human recombinant BMP‐7 protein were added to the matrix. After the cultivation period, histological and immunohistochemical investigations were performed. In addition, the aggrecan core protein and type‐II collagen mRNA concentrations were measured by real‐time PCR. Histological staining for proteoglycan and collagen type‐II protein and quantification via digital image processing revealed a significantly higher content in the samples cultivated with BMP‐7 loaded microspheres in comparison to the control samples. Moreover, the collagen gel scaffold was partially remodeled by the chondrocytes and replaced by newly synthesized extracellular matrix. Cellular proliferation as well as apoptosis were low. In conclusion, we consider the PGLA microsphere system to be a functional device for the delivery of growth factors during the cultivation of articular chondrocytes leading to an increased content of type‐II collagen and proteoglycan in the extracellular matrix. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2006.
Preparing for “diastole”: Advanced training opportunities for academic hospitalists
Authors: Arora Vineet , Fang Margaret C. , Kripalani Sunil , Amin Alpesh N.
Published: December 2006

Academic hospital medicine can be described as comprising periods of “systole,” during which hospitalists provide clinical care, and periods of “diastole,” the portion of a hospitalist's time spent in nonclinical activities. Far from being a period of relaxation, diastole is an active component of a hospitalist's work, the time devoted to the pursuit of career advancement. This period is a critical opportunity for career development in terms of medical research, education, quality improvement, or administration. An appropriate balance of systole and diastole may potentially prevent burnout and allow hospitalists opportunities to focus on academic advancement. Although an increasing number of residency graduates opt for a career in academic hospital medicine, few are prepared for the period of diastole. This article describes several career options in academic hospital medicine, specifically, opportunities in education, research, quality improvement, and administrative opportunities. By informing future hospitalists about the career opportunities within academic hospital medicine possible through managing their diastolic time, we hope that future generations of trainees will be better prepared to enter this field. Journal of Hospital Medicine 2006;1:368–377. © 2006 Society of Hospital Medicine.
Tendons and ligaments are anatomically distinct but overlap in molecular and morphological features—a comparative study in an ovine model
Authors: Rumian Adam P. , Wallace Andrew L. , Birch Helen L.
Published: January 2007

Tendons and ligaments are similar in composition but differ in function. Simple anatomical definitions do not reflect the fact individual tendons and ligaments have unique properties due to their adaptation to a specific role. The patellar tendon is a structure of particular clinical interest. A null hypothesis was declared stating that the patellar tendon is not significantly different in terms of matrix composition and collagen fibril diameter to other tendons. The lateral and medial collateral ligaments (LCL, MCL), anterior and posterior cruciate ligaments (ACL, PCL), together with the long digital extensor, superficial digital extensor, and patellar tendons (LDET, SDFT, PT) were harvested from three cadaveric ovine hindlimbs. The extracellular matrix was assessed in terms of water, collagen, and total sulphated glycosaminoglycan (GAG) content. The organization of the collagen component was determined by an ultrastructural analysis of collagen fibril diameter distributions, together with values for the collagen fibril index (CFI) and mass‐average diameter (MAD). There were significant differences between ligaments and tendons. The PT had a bimodal collagen fibril diameter distribution with CFI 72.9%, MAD 202 nm, water content 53.1%, GAG content 2.3 µg/mg, and collagen content 73.7%, which was not significantly different from the other tendons. The results of this study support the null hypothesis suggesting that the patellar tendon is similar to other tendons and demonstrate that tendons have different characteristics to ligaments. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:458–464, 2007
The three paths: Meeting leadership challenges in China and India
Authors: Hedrick‐Wong Yuwa
Published: December 2006

Businesses in Asia, notably in China and India, have traditionally been endowed with entrepreneurial energy. Where they have often fallen short is in efficiently structured, professionally run, and inspirational corporate leadership. An analysis of the three routes through which individuals in China and India become business leaders will go a long way toward resolving this disconnect.
Getting to the source: Four perspectives on leadership
Authors: Day David V. , O'Connor Patricia M. G.
Published: December 2006

In the midst of all the innovative business strategies being deployed to respond to globalization, one fundamental aspect often remains unexamined: how leadership is accomplished. What are the most prevalent forms of organizational leadership and their relative strengths and weaknesses, and how can a leader reflect on the type of leadership found in his or her organization and whether that approach is the most appropriate for attaining the organization's strategic goals?
On a class of holomorphic functions representable by Carleman formulas in the disk from their values on the arc of the circle
Authors: Aizenberg Lev , Vidras Alekos
Published: December 2006

Let D be a unit disk andM be an open arc of the unit circle whose Lebesgue measure satisfies 0 < l (M) < 2π. Our first result characterizes the restriction of the holomorphic functions f ∈ ℋ︁(D), which are in the Hardy class ℋ︁1 near the arcM and are denoted by 𝒩 ℋ︁1M (𝒟), to the open arcM. This result is a direct consequence of the complete description of the space of holomorphic functions in the unit disk which are represented by the Carleman formulas on the open arc M.

As an application of the above characterization, we present an extension theorem for a function f ∈ L 1(M) from any symmetric sub‐arc L ⊂ M of the unit circle, such that $ \bar L $ ⊂ M, to a function f ∈ 𝒩 ℋ︁1L (𝒟). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The maximal operator in Lebesgue spaces with variable exponent near 1
Authors: Hästö Peter A.
Published: December 2006

This article contains results about the boundedness of the Hardy–Littlewood maximal operator in variable exponent Lebesgue spaces. We study the situation where the exponent approaches one in some parts of the domain. We show that the boundedness depends on how fast the exponent approaches one and give nearoptimal bounds for necessary and sufficient growths. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On characterizations of the image of the Gelfand transform of commutative Banach algebras
Authors: Inoue Jyunji , Takahasi Sin‐Ei
Published: December 2006

In this paper, we propose a new method to characterize in terms of “quasi‐topology” the image of Gelfand transform of commutative Banach algebras. Our studies in this paper were inspired by the work of R. Doss in 1967–1968.

Among other things, we consider a generalization of Doss' result ([3, Theorem 1] which characterizes Fourier transforms of group algebras) to the case of general commutative Banach algebras.

In the last two sections, we study several concrete Banach algebras to see whether our characterization are valid or not; concrete Banach algebras we consider are ideals and quotient algebras of group algebras, Segal algebras for locally compact abelian groups, Lipsitz algebras,C1([0, 1]),C1(ℝ) and etc. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fano threefolds with sections in Ω1V (1)
Authors: Jahnke Priska , Radloff Ivo
Published: December 2006

We study Fano threefolds with Picard number one equipped with a holomorphic section in Ω1V (1). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crosslinking in Acetoacetoxy Functional Waterborne Crosslinkable Latexes
Authors: González Iñigo , Asua José M. , Leiza José R.
Published: December 2006

Chain crosslinking through the different stages of the production of acetoacetoxy ethyl methacrylate (AAEMA) containing acrylic latexes was studied; namely, during the synthesis step, after latex neutralization and after crosslinking with diamines. The gel content of the latex increased with increasing amounts of the functional AAEMA monomer likely due to dimethacrylate impurities contained in the monomer. Moreover, the neutralization of the latex with ammonia had important implications in the microstructure of the polymer. A base catalyzed Michael addition reaction between acetaocetoxy groups and terminal double bonds present in the polymer particles produced chain pre‐crosslinking that affected the further crosslinking reaction with diamines. The compatibility of the diamines with the polymer matrix and the ratio diamine/acetoacetoxy used to crosslink the latex during film formation also played an important role in the crosslinking efficiency as evaluated by solvent resistance of crosslinked films.
The Role of Components in Waterbased Microsphere Acrylic Psa Adhesive Properties
Authors: Kajtna J. , Krajnc M. , Golob J.
Published: December 2006

In this paper the batch suspension copolymerization of ethyl acrylate/2 ethyl hexylacrylate (EA/2‐EHA) for production of suspension‐based microsphere acrylic pressure sensitive adhesives (PSA) is presented. The effects on the adhesion properties of PSA different process (reaction temperature and stirrer speed) as well as chemical parameters (amount of EA, initiator concentration) are discussed. The conversion was monitored in‐line using Attenuated Total Reflectance‐Fourier Transform Infrared (ATR‐FTIR) spectroscopy and the results were compared with the standard gravimetrical method. The glass transition temperatures (Tg) of the PSAs were measured using differential scanning calorimetry (DSC) technique, while molecular weight distribution (MWD) was determined by gel permeation chromatography (GPC). The adhesion properties of PSAs were characterized via the measurements of tack, peel adhesion and peel strength. The results of the experiments have shown that the kinetics of the suspension polymerization for production of PSAs is significantly affected by temperature of polymerization and the initiator concentration, but are shown to be relatively independent of the EA amount and the stirrer speed. The tack, peel and shear strength depend on the mean particle size and particle size (PS) distribution (PSD) and Tg. The mean particle size and PSD depend primarily on the stirrer speed during the PSA synthesis process, while the Tg is most affected by amount of EA used for the synthesis. The results have also shown a rather unexpected relationship between MWD of the PSAs and the applicative properties: tack, peel and shear are seen to be increasing to the decreasing values of weight average MWD, which is the exact opposite of the previously published research. The most likely explanation for this relationship is the formation of a gel during the synthesis of PSA.
Comparison of Vinyl Acetate ‐ Butyl Acrylate Emulsion Copolymerizations Conducted in a Continuous Pulsed Sieve Plate Column Reactor and in a Batch Stirred Tank Reactor
Authors: Carvalho Antonio C.S.M. , Chicoma Dennis , Sayer Claudia , Giudici Reinaldo
Published: December 2006

In this work, vinyl acetate/butyl acrylate emulsion copolymerizations carried out in a continuous tubular reactor (pulsed sieve plate column, PSPC) were compared to those conducted in a semibatch stirred tank reactor under similar operational conditions. In order to minimize the compositional drift along the PSPC, reactions were carried out with different numbers (2, 3 and 4) of lateral feed streams of the more reactive monomer (butyl acrylate). For comparison, fed batch reactions were conducted with the same number of intermittent shot additions of butyl acrylate, at the corresponding batch times. Both systems (tubular and semibatch) with distributed feeding of more reactive monomer are able to reduce composition drift thus providing more uniformity in copolymer composition. In addition, the tubular reactor presents much better control of temperature than the tank reactor, which is important to achieve higher productivity.
Study and Control of the Distribution of Elastomer in High Impact Polypropylene
Authors: Bouzid Djallel , Gaboriaud Fabien , McKenna Timothy F.L.
Published: December 2006

In an initial step, different techniques were used to investigate the distribution and properties of the rubbery domains inside individual high impact polypropylene particles. Both Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to visualise the local of rubber nodules as a function of the quantity of ethylene propylene rubber (EPR) in the final product. It was demonstrated that the EPR forms first as nodules near the centre of the homopolymer particles, and then accumulates as the rubber quantity increases.
Parkinson's disease and working capacity
Authors: Martikainen Kirsti K. , Luukkaala Tiina H. , Marttila Reijo J.
Published: December 2006

The purpose of the present study was to establish how Parkinson's disease (PD) affects working capacity. Altogether, 937 (70%) of 1,343 working‐aged members of the Finnish Parkinson Association participated in a questionnaire study. The ages of the subjects were between 29 and 65 years, median 59.0 years; 508 (54%) were men. The median (quartile range) duration of PD symptoms was 7.3 (4.3–11.3) years, and the median self‐estimated severity of the disease on the Hoehn & Yahr scale was 2. Only 150 of 937 subjects (16%) were still working: 112 (12%) full‐time and 38 (4%) part‐time. Among those 343 (37%) who had retired purely because of PD at a median age of 53.4 years, the median working time was 1.7 years after established diagnosis. In part‐time work, PD patients had been able to continue for a median of 4.3 years. PD often leads to early retirement; compared with the general Finnish population of similar age, PD patients had retired on the average 6 years earlier. Young age, mild symptoms, and short duration of the disease as well as adjustments enabling easier employment were associated with the possibility to continue longer in the work force. © 2006 Movement Disorder Society
Changing perspectives on the benefits of newborn screening
Authors: Bailey Donald B. , Beskow Laura M. , Davis Arlene M. , Skinner Debra
Published: December 2006

The likelihood of benefit is fundamental to decision making about newborn screening. But benefit is construed in different ways by different stakeholders. This article begins with a review of benefit as considered historically by various expert panels and organizations. We then show how 78 conditions fared when experts recently rated them on benefit using a scoring system recommended by a task force of the American College of Medical Genetics. Finally, we analyze how benefit is reflected in the public comments submitted in response to the ACMG report. Results show that benefit has been and remains a core consideration for screening decisions. Historically the focus has been on improved physical health as a result of medical treatment; however, in only 4 of the 78 conditions rated does newborn screening prevent all negative consequences. In fact the majority of both core conditions (51.7%) and secondary targets (87.5%) recommended in the ACMG report were rated as having treatments that prevented only some negative consequences. All conditions rated had perceived benefits for family and society, but currently no conditions are screened on the basis of family or societal benefits alone. No agreed‐upon threshold exists for what would be considered meaningful benefit, and stakeholder groups differ in their perceptions of benefit. We conclude by suggesting several key research studies needed to further inform public policy. © 2006 Wiley‐Liss, Inc. MRDD Research Reviews 2006;12:270–279.
The regional genetic and newborn screening service collaboratives: The first two years
Authors: Puryear Michele , Weissman Gloria , Watson Michael , Mann Marie , Strickland Bonnie , van Dyck Peter C.
Published: December 2006

Newborn screening and genetic technologies are expanding and changing rapidly, increasing the demand for genetic specialty services. Because of the scarcity and geographic maldistribution of genetic specialty services, access to these services is a critical issue. This article discusses some of the efforts initiated by the Maternal and Child Health Bureau of the Health Resources and Services Administration, particularly the establishment of regional genetic and newborn screening collaboratives to improve access to these services and expertise. MRDD Research Reviews 2006;12:288–292. Published 2006 Wiley‐Liss, Inc.