bluuebunny/crossref_metadata_2025 huggingface dataset:
The Detection of MAPK Signaling
Authors: Shaul Yoav , Seger Rony
Published: February 2006

Mitogen‐activated protein kinase (MAPK) cascades are central pathways that participate in the intracellular transmission of extracellular signals. Each of the MAPK signaling cascades seems to consist of three to five tiers of protein kinases that sequentially activate each other by phosphorylation. Since the majority of MAPK cascade components are kinases, the methods used to detect their activation involve determining phosphorylation state and protein kinase activities. The primary method describes the use of immunoblotting with specific anti‐phospho antibody to detect activation of MAPK components. Alternative methods described are immunoprecipitation of desired protein kinases followed by phosphorylation of specific substrates and the use of an in‐gel kinase assay. These methods have proven useful in the study of the MAPK signaling cascades.
Minimizing Variation Due to Genotype and Environment
Authors: Argmann Carmen A. , Auwerx Johan
Published: February 2006

Mouse models are increasingly popular tools to study and characterize the molecular and physiological bases for human diseases. Due to the readily available genetic tools to construct mouse models of complex diseases, the flow of efficient and vigilant mouse phenotyping has now become the bottleneck in mouse functional genomics. This unit addresses the importance of minimizing and defining confounding genetic and environmental sources of variability.
Nuclear DNA Content Analysis of Plant Seeds by Flow Cytometry
Authors: Sliwinska Elwira
Published: February 2006

Procedures describing the utilization of seeds or their parts for flow cytometric determination of plant ploidy and endopolyploidy, genome size, and cell cycle activity are presented. The methods have been developed for a single‐fluorescence‐parameter flow cytometer, equipped with light sources for 488‐nm and UV‐light illumination. The procedures presented in this unit utilize the two most widely used fluorochromes for plant DNA content analysis, propidium iodide (PI) and 4′,6‐diamidino‐2‐phenylindole (DAPI). These methods provide an alternative to estimation of DNA content based on the fluorescence of DNA in cell nuclei isolated from plant leaves. In some instances seeds are more suitable for analysis than leaves, e.g., when plant material must be transported for a long distances or stored for prolonged periods before flow cytometric analysis, or when leaves contain fluorochrome‐staining inhibitors. In addition, flow cytometric determination of nuclear replication stages in seeds gives information about their physiological status (e.g., maturity, advancement of germination), which is valuable to seed producers and technologists.
Characterization of Nuclear Receptor Ligands by Multiplexed Peptide Interactions
Authors: Iannone Marie A.
Published: February 2006

This unit describes a method to evaluate the effect that small molecules have on the binding interactions of a nuclear receptor protein with a series of peptides. The multiplexed microsphere‐based system employs peptide‐coupled microsphere populations that are fluorescently unique and thereby identifiable by flow cytometric analysis. Up to 100 different peptide–nuclear receptor interactions may be analyzed in a single well of a 96‐well microtiter plate. This approach allows rapid and sensitive characterization of nuclear receptor ligands based on nuclear receptor protein–peptide interaction profiles. Since nuclear receptor binding interactions are dynamically related to protein conformation, the approach allows rapid evaluation of nuclear receptor ligands that may impart unique protein structure. The no‐wash format and the high surface density of the microsphere‐coupled interaction partner offer a moderately high‐throughput system to examine low‐ to high‐affinity interactions with excellent sensitivity. This approach, although described for nuclear receptors, may also be applied to other types of molecular interactions.
Phospholipases and Galactolipases Trigger Oxylipin‐Mediated Wound‐Activated Defence in the Red Alga Gracilaria chilensis against Epiphytes
Authors: Lion Ulrich , Wiesemeier Theresa , Weinberger Florian , Beltrán Jessica , Flores Verónica , Faugeron Sylvain , Correa Juan , Pohnert Georg
Published: February 2006

We investigated the wound response of the commercially important red alga, Gracilaria chilensis, in order to obtain insight into its interaction with epiphytic pests. After wounding, the host releases free fatty acids as well as the hydroxylated eicosanoids, 8R‐hydroxy eicosatetraenoic acid (8‐HETE) and 7S,8R‐dihydroxy eicosatetraenoic acid (7,8‐di‐HETE). While the release of free arachidonic acid and subsequent formation of 8‐HETE is controlled by phospholipase A, 7,8‐di‐HETE production is independent of this lipase. This dihydroxylated fatty acid might be directly released from galactolipids. Physiologically relevant concentrations of oxylipins reduced spore settlement of Acrochaetium sp. (Rhodophyta, Acrochaetiaceae) and suppressed the development of hapteria in Ceramium rubrum (Rhodophyta, Ceramiaceae) when these model epiphytes were exposed to artificial surfaces that contained 8‐HETE or 7,8‐di‐HETE. Thus, the immediate release of oxylipins can be seen as G. chilensis defence against epiphytes.
Approaches to corporate sustainability among German companies
Authors: Hahn Tobias , Scheermesser Mandy
Published: February 2006

In this article we present the results of an online survey on the state of corporate sustainability in German companies. The survey focused on the meaning and relevance of sustainability to German companies, the motivations behind their commitment to sustainability and the use of different management tools to implement sustainability in corporate practice. Although the majority of the companies declared that sustainability plays an important role, our analysis reveals considerable differences between these companies' approaches to corporate sustainability. A cluster analysis enables us to distinguish between three significantly distinct types of approach to corporate sustainability among the respondents: sustainability leaders, environmentalists and traditionalists. These three types are characterized and discussed against previous research. The results suggest that there are substantial differences with regard to the motivation for and the implementation of corporate sustainability that are covered behind the corporate rhetoric of a high commitment to sustainability. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
On the transposition of Gm–C filters to DC stabilized log‐domain filters
Authors: Psychalinos Costas
Published: February 2006

High‐order log‐domain filters could be designed by transposing the already known linear‐domain Gm–C filter topologies to the corresponding topologies in the log‐domain. This is achieved by using a non‐linear transconductor configuration, where the output current is exponentially related to its input and output voltages. A drawback of the non‐linear transconductor configuration already introduced in the literature is that a number of the transposed log‐domain filter topologies suffer from DC instability, while in some others a DC offset current appears at their output. In order to eliminate the aforementioned problems a modified non‐linear transconductor configuration for transposing Gm–C filter topologies to log‐domain filter topologies is introduced in this paper. The achieved improvements are demonstrated through a number of log‐domain filter configurations derived using the already introduced and the proposed transposition schemes. Copyright © 2006 John Wiley & Sons, Ltd.
Cytokine analysis to predict immunosuppression
Authors: Barten Markus J. , Rahmel Axel , Bocsi József , Boldt Andreas , Garbade Jens , Dhein Stefan , Mohr Friedrich W. , Gummert Jan F.
Published: February 2006

Background

Recently, it has been realized that TH1/TH2 cytokine production offer the unique possibility to predict drug efficacy. However, there is still an incessant need to explore assay conditions and techniques of analyzing cytokines, which are specific and reliable for monitoring drug efficacy.

Methods

In this study we used the multiplex bead array technique to detect cytokines of TH1/TH2 cells in whole blood of heart transplanted (HTx) recipients.

Results

We found significantly different levels of cytokine expression in HTx recipients compared with cytokine levels in patients prior to HTx. Furthermore, particular cytokine levels were significantly decreased 2 h after drug dosing, compared with cytokine levels before dosing in mitogen‐stimulated whole blood.

Conclusions

Cytokine analysis with the multiplex array technique in mitogen‐stimulated whole blood provides the possibility to predict immunosuppression. © 2006 International Society for Analytical Cytology
B lymphocytes in humans express ZAP‐70 when activated in vivo
Authors: Cutrona Giovanna , Colombo Monica , Matis Serena , Reverberi Daniele , Dono Mariella , Tarantino Vincenzo , Chiorazzi Nicholas , Ferrarini Manlio
Published: February 2006

ZAP‐70 is a protein tyrosine kinase initially found in T and NK cells. Recently, this important signaling element was detected in leukemic B cells from a subgroup of patients with B cell chronic lymphocytic leukemia (B‐CLL). In this study, ZAP‐70 was detected in normal B cells from human tonsils, but not from peripheral blood. The cDNA sequence of B cell ZAP‐70 was the same as that in T cells. Germinal center B cells and plasma cells had a substantial proportion of ZAP‐70+ cells, while memory and follicular mantle B cells, which contain low numbers of activated B cells, expressed relatively little ZAP‐70. A cell fraction of IgD+, CD38+ B cells, which are comprised of many in vivo activated B cells, exhibited the highest levels of ZAP‐70. Density gradient fractionation of tonsil B cells confirmed that ZAP‐70 was not expressed by resting B cells, but was expressed by buoyant, in vivo activated B cells. In these B cells, the expression of ZAP‐70 correlated with that of CD38 and not with that of CD5, a hallmark of B‐CLL cells. B‐CLL cells are activated cells and their ZAP‐70 expression reflects a normal property of activated B cells populations rather than a neoplastic aberration.
Binding specificity of Toll‐like receptor cytoplasmic domains
Authors: Brown Victoria , Brown Rachel A. , Ozinsky Adrian , Hesselberth Jay R. , Fields Stanley
Published: February 2006

MyD88 participates in signal transduction by binding to the cytoplasmic Toll/IL‐1 receptor (TIR) domains of activated Toll‐like receptors (TLR). Yeast two‐hybrid experiments reveal that the TIR domains of human TLR differ in their ability to associate with MyD88: The TIR of TLR2 binds to MyD88 but the TIR of the closely related TLR1, 6, or 10 do not. Using chimeric TIR domains, we define the critical region responsible for differential MyD88 binding, and use a computational analysis of the critical region to reveal the amino acids that differ between MyD88 binders and non‐binders. Remarkably, a single missense mutation created in TLR1 (N672D) confers on it the ability to bind MyD88, without affecting its association with other proteins. Mutations identified as critical for MyD88 binding also affect signaling of TLR pairs in mammalian cells. To investigate the difference between MyD88 binders and non‐binders, we identify novel interacting proteins for each cytoplasmic domain of TLR1, 2, 6, and 10. For example, heat shock protein (HSP)60 binds to TLR1 but not to TLR2, and HSP60 and MyD88 appear to bind the same region of the TIR domain. In summary, interactions between the TLR, MyD88, and novel associated proteins have been characterized.
STAT‐1‐mediated repression of monocyte interleukin‐10 gene expression in vivo
Authors: VanDeusen Jeffrey B. , Shah Manisha H. , Becknell Brian , Blaser Bradley W. , Ferketich Amy K. , Nuovo Gerard J. , Ahmer Brian M. M. , Durbin Joan , Caligiuri Michael A.
Published: February 2006

There have been substantial advances in understanding the events that regulate gene expression at the cellular and molecular level; however, there has been limited progress integrating this information to understand how biological systems function in vivo. For example, the anti‐inflammatory cytokine IL‐10 is thought to down‐regulate the effects of the pro‐inflammatory cytokine IFN‐γ on monocyte activation following LPS stimulation. However, the often‐postulated reciprocal regulation of IL‐10 gene expression by IFN‐γ has not been studied in vivo. Here we demonstrate that the regulation of IL‐10 gene expression has at least two phases following challenge with LPS or a gram‐negative organism. In C57BL/6 mice, early IL‐10 induction occurs independently of STAT‐1, while a delayed active repression of IL‐10 gene expression is critically dependent on STAT‐1, but only partially dependent upon IFN‐α/β and IFN‐γ. This in vivo IL‐10 production comes from blood monocytes, but not tissue macrophages, and cannot be reproduced in vitro. This study provides new insights into the regulation of IL‐10 following challenge with a gram‐negative organism, and highlights the importance of studying these cytokine regulatory pathways in vivo.
Surface expression of HSP72 by LPS‐stimulated neutrophils facilitates γδT cell‐mediated killing
Authors: Hirsh Mark I. , Hashiguchi Naoyuki , Chen Yu , Yip Linda , Junger Wolfgang G.
Published: February 2006

During inflammation and sepsis, accumulation of activated neutrophils causes lung tissue damage and organ failure. Effective clearance of neutrophils reduces the risk of organ failure; however, its mechanisms are poorly understood. Because lungs are rich in γδT cells, we investigated the physiological role of these cells in the protection of lung tissue from infiltrating neutrophils. In a mouse model of sepsis, we found that the lungs of survivors contained significantly higher numbers of γδT cells than those of mice that died from sepsis. The number of γδT cells correlated inversely with the number of neutrophils in the lungs and with the degree of lung tissue damage. LPS rapidly elicited the expression of heat shock protein (HSP) 72 on the surface of human neutrophils. Inhibitors of transcription, protein synthesis, and intracellular protein transport blocked HSP72 expression, indicating that de novo synthesis is required. γδT cells targeted and rapidly killed LPS‐treated neutrophils through direct cell‐to‐cell contact. Pre‐treatment with neutralizing antibodies to HSP72 diminished neutrophil killing. Our data indicate that HSP72 expression on the cell surface predisposes inflamed neutrophils to killing by γδT cells. This intercellular exchange may allow γδT cells to resolve inflammation and limit host tissue damage during sepsis.
Proton‐Coupled Redox Chemistry, Oxidative Reactivity, and Electronic Characterization of Aqua‐, Hydroxo‐, and Oxo‐Triruthenium Clusters
Authors: Nunes Genebaldo S. , Alexiou Anamaria D. P. , Araki Koiti , Formiga André L. B. , Rocha Reginaldo C. , Toma Henrique E.
Published: February 2006

The pH‐dependent electronic and electrochemical properties of a series of triangular μ3‐oxo‐centered trinuclear clusters of the type [Ru3O(Ac)6(py)2(OHx)]n (Ac = acetate; py = pyridine; x = 0, 1, or 2; where the formal oxidation states on the metal ions range from +II to +IV) have been investigated with emphasis on the elucidation of the successive proton‐coupled redox processes spanning the interconvertible aqua‐ (x = 2), hydroxo‐ (x = 1), and oxo‐ (x = 0) forms, from which the complete Pourbaix diagram has been proposed. From the spontaneous slow coupling reaction of the monomeric cluster in its deprotonated (oxo) form at high pH, the μ‐oxo‐bridged cluster dimer (i.e. {(py)2(Ac)6ORu3}‐O‐{Ru3O(Ac)6(py)2}) has been isolated and fully characterized by spectroelectrochemistry as well. A further understanding of the underlying electronic interactions across the various oxidation and protonation states, and the role of such phenomena in the activation of the Ru–O bonding system in oxygen‐transfer catalysis, have also been explored. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Squamous cell carcinoma of the parotid gland
Authors: Ying Yu‐Lan Mary , Johnson Jonas T. , Myers Eugene N.
Published: February 2006

Background.

Our objective was to evaluate the outcome of patients treated for squamous cell carcinoma (SCC) of the parotid gland.

Methods.

We conducted a retrospective chart review of the tumor registry from 1982 through 2003 at a tertiary referral medical center. Patients with SCC of the parotid gland were identified and followed for a minimum of 2 years after therapy.

Results.

SCC involving the parotid was identified in 66 patients. The tumor was a metastasis from a known primary site in 41 patients (62%). In 16 patients (24%), no other primary site was identified, and the tumor may have originated in the parotid gland. Nine patients (14%) were undetermined. Therapy frequently included surgery. The integrity of the facial nerve was preserved in 92% of surgical patients. Only eight patients initially had clinical evidence of cervical metastasis; however, cervical metastasis was identified in 25 patients (44%), changing the course of therapy.

Conclusion.

SCC of the parotid gland was metastatic from a known primary tumor in more than half of the patients. The most common site of the primary tumor was a cutaneous malignancy of the head and neck. The high incidence of cervical lymph node involvement underscores the diagnostic and therapeutic importance of neck dissection with parotidectomy. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Cardiovascular and respiratory complications after major head and neck surgery
Authors: Buitelaar Dirk R. , Balm Alfons J. M. , Antonini Ninja , van Tinteren Harm , Huitink Johannes M.
Published: February 2006

Background.

Our aim was to gain insight into the incidence rates for, distribution of, and risk factors of postoperative cardiovascular and respiratory complications in major head and neck surgery.

Methods.

We performed a retrospective review of 469 patients who had undergone primary major head and neck surgery. Outcome measures were incidence rates, risk factors, and distribution over time for postoperative cardiovascular and respiratory complications. A multivariate analysis was performed.

Results.

The incidence rates for cardiovascular and respiratory complications were 57 of 469 (12%) and 50 of 469 (11%), respectively. The incidence rate for heart failure exceeded that for pneumonia. The peak incidence for cardiovascular complications was on the first postoperative day; for respiratory complications, on the second postoperative day. Risk factors for cardiovascular complications were age, pulmonary disease, alcohol abuse, and tumor location; risk factors for respiratory complications were pulmonary disease, previous myocardial infarction, and American Society of Anesthesiologists (ASA) grade.

Conclusion.

In this study, the incidence rates for cardiovascular and respiratory complications were very similar. The first postoperative day was crucial with regard to cardiovascular complications. Age and chronic pulmonary diseases were the common risk factors for cardiovascular and respiratory complications. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Polymorphisms in the genes involved in the arachidonic acid‐pathway, fish consumption and the risk of colorectal cancer
Authors: Siezen Christine L.E. , Bueno‐de‐Mesquita H. Bas , Peeters Petra H.M. , Kram Nicolien R. , van Doeselaar Marina , van Kranen Henk J.
Published: February 2006

The objective of this study on colorectal cancer was to investigate the associations between SNPs in the genes involved in the arachidonic acid (AA)‐pathway, their haplotypes and colorectal cancer. Moreover, interactions between SNPs and fish consumption were considered. In this study, a total of 508 cases and 772 controls were included, originating from 2 prospective cohorts, the Monitoring Project on Cardiovascular Disease Risk Factors (PPHV) and Diagnostisch Onderzoek Mammacarcinoom (DOM). Genotypes of 23 SNPs in 7 candidate genes were determined and the modifying effect of fish consumption was considered. A protective effect of the minor allele of SNP V102V in PTGS2 was observed (odds ratio (OR), 0.37; 95% confidence intervals (CI), 0.16–0.87). The haplotype representing this allele showed a weaker inverse association, indicating that 2 alleles are necessary to obtain this protective effect. Fish consumption data was available for 209 cases and 418 controls. Increased fish consumption was inversely associated with cancer, although not significant (OR, 0.83; 95% CI, 0.57–1.20). Despite the substantial reductions in cancer risk for some genotypes in combination with high fish intake, no significant interactions between any SNP studied and fish consumption were observed. We have previously described an association between colorectal adenomas and SNP V102V in PTGS2 and have now confirmed this association for colorectal adenocarcinomas. Fish consumption of once a week or more might protect against colorectal cancer, but no significant interactions with SNPs in the genes involved in the AA‐pathway could be detected within the study. © 2006 Wiley‐Liss, Inc.
Zooplankton Seasonal Abundance of South AmericanSaline Shallow Lakes
Authors: Echaniz Santiago Andrés , Vignatti Alicia María , De Paggi Susana José , Paggi Juan César , Pilati Alberto
Published: February 2006

The central provinces of Argentina are characterized by the presence of a high number of shallow lakes, located in endorheic basins, many of which have elevated salinities as well as eutrophic or hypereutrophic condition. The zooplankton of four saline shallow lakes of the province of La Pampa was studied on a monthly basis during a 2‐year period to determine its temporal and spatial variation.

The surface of these shallow lakes (<2.5 m depth) varied between 56.8 and 215.9 ha, and some have from 8.4 to 20.8 g · l–1. The more saline lakes have “clear” water and the less saline lakes “turbid” water. Fishes, Jenynsia multidentata , were present in only two lakes during the last two months of the studied period.

The zooplankton was composed of 17 taxa of Rotifera, 5 taxa of Cladocera and 4 taxa of Copepoda. The low diversity and the faunistic composition are characteristic of saline environments. Although the studied lakes share 38% of the species, the faunistic similarity was higher between the two least saline lakes. The lowest diversity was found in the two most saline lakes.

All four shallow lakes were characterized by their very high zooplankton density, especially in the least saline lakes (<80000 ind · l–1). The abundance is significantly correlated with the water transparency but not with salinity.

The zooplankton temporal variation was characterized by the alternation of macro‐ and microzooplankton, probably regulated by competition and intrazooplanktonic predation. In each lake, the spatial abundance distribution of the macro‐ and microzooplankton was homogeneous. It was related to the shallow depht of the lakes and their polymictic condition.

The Scheffer model on alternative states in shallow lakes acknowledges that it cannot be applied to saline lakes because Daphnia , the main responsible for the clear water state, is not tolerant to high salinity. Our study shows that the most saline lakes, where the halophylic Daphnia menucoensis is abundant, have also the most clear waters. Another difference that we found with regards to the mentioned model is that, in turbid lakes, it could not have had a top‐down control on macrozooplankton exerted by fishes because in these lakes fishes were practically absent. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of hydroxyapatite–polyphosphazene polymer composites at physiologic temperature
Authors: Greish Y. E. , Bender J. D. , Lakshmi S. , Brown P. W. , Allcock H. R. , Laurencin C. T.
Published: February 2006

Aspects of the formation of bone analog composites at 37°C are described. The composites are composed of hydroxyapatite (HAp) and the calcium salt of a biocompatible polymer and are capable of forming under in vivo conditions. Composite formation involves the formation of monolithic HAp from particulate calcium phosphate precursors while Ca ions liberated to the aqueous medium in which this reaction is occurring form crosslinks with the acidic polymer. The reactants are poly[bis(carboxylatophenoxy)phosphazene] (acid‐PCPP), tetracalcium phosphate [Ca4(PO4)2O, TetCP], and anhydrous dicalcium phosphate (CaHPO4, DCPA). The effects of the proportion of polymer (5, 10, or 15 wt %) on the kinetics of HAp formation were studied. Compositional evolution of the solid calcium phosphates present was followed by X‐ray diffraction and infrared spectroscopy analyses. HAp formation through a dissolution‐precipitation process provided a mildly alkaline medium suitable for deprotonation of the acid‐PCPP and for the formation of the calcium crosslinks, as monitored by infrared spectroscopy. Concurrence of crosslinking of the polymer and HAp formation was established, indicating true composite formation can be realized at physiologic temperature. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Strong calcium phosphate cement‐chitosan‐mesh construct containing cell‐encapsulating hydrogel beads for bone tissue engineering
Authors: Weir Michael D. , Xu Hockin H.K. , Simon Carl G.
Published: February 2006

Calcium phosphate cement (CPC) can conform to complex cavity shapes and set in situ to form bioresorbable hydroxyapatite. The aim of this study was to introduce cell‐encapsulating alginate hydrogel beads into CPC and to improve the mechanical properties using chitosan and fiber mesh reinforcement. Because the CPC setting was harmful to the MC3T3‐E1 osteoblast cells, alginate was used to encapsulate and protect the cells in CPC. Cells were encapsulated into alginate beads, which were then mixed into three pastes: conventional CPC, CPC‐chitosan, and CPC‐chitosan‐mesh. After 1 day culture inside the setting cements, there were numerous live cells and very few dead cells, indicating that the alginate beads adequately protected the cells. Cell viability was assessed by measuring the mitochondrial dehydrogenase activity, using a Wst‐1 colorimetric assay. Absorbance at 450 nm (arbitrary units) (mean ± SD; n = 5) was 1.36 ± 0.41 for cells inside conventional CPC, 1.29 ± 0.24 for cells inside CPC‐chitosan composite, and 0.73 ± 0.22 for cells inside CPC‐chitosan‐mesh composite. All three values were similar to 1.00 ± 0.14 for the control with cells in beads in the cell culture medium without any CPC (Tukey's at p = 0.05). Flexural strength for conventional CPC containing cell‐encapsulating beads was 1.3 MPa. It increased to 2.3 MPa when chitosan was incorporated. It further increased to 4.3 MPa with chitosan and the reinforcement from one fiber mesh, and 9.5 MPa with chitosan and three sheets of fiber mesh. The latter two strengths matched reported strengths for sintered porous hydroxyapatite implants and cancellous bone. In summary, cell‐encapsulated‐alginate‐CPC constructs showed favorable cell viability. The use of chitosan and mesh progressively improved the mechanical properties. These strong, in situ hardening, and cell‐seeded hydroxyapatite cements may have potential for bone tissue engineering in moderate stress‐bearing applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Chondrogenic differentiation of murine and human mesenchymal stromal cells in a hyaluronic acid scaffold: Differences in gene expression and cell morphology
Authors: Lisignoli Gina , Cristino Sandra , Piacentini Anna , Zini Nicoletta , Noël Danièle , Jorgensen Christian , Facchini Andrea
Published: February 2006

Chondrogenesis is a complex process characterized by a sequence of different steps that start with the condensation of the cells, followed by the expression of specific components, such as collagens and proteoglycans. We evaluated in vitro chondrogenic differentiation of C3H10T1/2 murine mesenchymal cells and compared them with human mesenchymal stromal cells (h‐MSCs) in a hyaluronic acid scaffold. We analyzed (from day 0 to day 28) cellular morphology, proliferation, and chondrogenic/osteogenic gene expression at different time points. Our data demonstrate that, during chondrogenic differentiation, murine cells proliferate both in the absence and presence of TGFβ, while h‐MSCs require the presence of this activating factor. Murine cells, even if viable, differentiate on hyaluronan scaffold, maintain a fibroblastic morphology, and form a capsule outside the scaffold. At the mRNA level, murine cells showed a decrease in collagen type I combined with a significant increase in collagen type II (from day 0), and aggrecan (on day 28), as found for h‐MSCs. Immunohistochemical data confirmed that chondrogenic differentiation of murine cells, induced by TGFβ, occurred only in some restricted areas inside the scaffold that were positive to collagen type II, but did not show a cartilage‐like tissue structure, as we had found using h‐MSCs. These data demonstrate that C3H10T1/2 murine cells, widely used as a chondrogenic model, show a different sequence of chondrogenic events in hyaluronic acid scaffold, compared with primary h‐MSCs. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Intra‐ and extracellular reactive oxygen species generated by blue light
Authors: Omata Y. , Lewis J.B. , Rotenberg S. , Lockwood P.E. , Messer R.L.W. , Noda M. , Hsu S.D. , Sano H. , Wataha J.C.
Published: February 2006

Blue light from dental photopolymerization devices has significant biological effects on cells. These effects may alter normal cell function of tissues exposed during placement of oral restorations, but recent data suggest that some light‐induced effects may also be therapeutically useful, for example in the treatment of epithelial cancers. Reactive oxygen species (ROS) appear to mediate blue light effects in cells, but the sources of ROS (intra‐ versus extracellular) and their respective roles in the cellular response to blue light are not known. In the current study, we tested the hypothesis that intra‐ and extracellular sources of blue light‐generated ROS synergize to depress mitochondrial function. Normal human epidermal keratinocytes (NHEK) and oral squamous cell carcinoma (OSC2) cells were exposed to blue light (380–500 nm; 5–60 J/cm2) from a dental photopolymerization source (quartz–tungsten–halogen, 550 mW/cm2). Light was applied in cell‐culture media or balanced salt solutions with or without cells present. Intracellular ROS levels were estimated using the dihydrofluorescein diacetate (DFDA) assay; extracellular ROS levels were estimated using the leucocrystal violet assay. Cell response was estimated using the MTT mitochondrial activity assay. Blue light increased intracellular ROS equally in both NHEK and OSC2. Blue light also increased ROS levels in cell‐free MEM or salt solutions, and riboflavin supplements increased ROS formation. Extracellularly applied ROS rapidly (50–400 μM, <1 min) increased intracellular ROS levels, which were higher and longer‐lived in NHEK than OSC2. The type of cell‐culture medium significantly affected the ability of blue light to suppress cellular mitochondrial activity; the greatest suppression was observed in DMEM‐containing or NHEK media. Collectively, the data support our hypothesis that intra‐ and extracellularly generated ROS synergize to affect cellular mitochondrial suppression of tumor cells in response to blue light. However, the identity of blue light targets that mediate these changes remain unclear. These data support additional investigations into the risks of coincident exposure of tissues to blue light during material polymerization of restorative materials, and possible therapeutic benefits. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Configuration distribution and designs of codes in the Johnson scheme
Authors: Etzion Tuvi
Published: February 2006

The main goal of this article is to present several connections between perfect codes in the Johnson scheme and designs, and provide new tools for proving Delsarte conjecture that there are no nontrivial perfect Codes in the Johnson scheme. Three topics will be considered. The first is the configuration distribution which is akin to the weight distribution in the Hamming scheme. We prove that if there exists an e‐perfect code $\cal C$ in the Johnson scheme then there is a formula which connects the number of vectors at distance i from any codeword in various codes isomorphic to $\cal C$. The second topic is the Steiner systems embedded in a perfect code. We prove a lower bound on the number of Steiner systems embedded in a perfect code. The last topic is the strength of a perfect code. We show two new methods for computing the strength of a perfect code and demonstrate them on 1‐perfect codes. We further discuss how to settle Delsarte conjecture. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 15–34, 2007
D‐optimal designs and group divisible designs
Authors: Tamura Hiroki
Published: February 2006

We obtain new conditions on the existence of a square matrix whose Gram matrix has a block structure with certain properties, including D‐optimal designs of order $n\equiv 3 \pmod 4$, and investigate relations to group divisible designs. We also find a matrix with large determinant for n = 39. © 2006 Wiley Periodicals, Inc. J Combin Designs 14: 451–462, 2006
Heterogeneity of the Ca2+ sensitivity of secretion in a pituitary gonadotrope cell line and its modulation by protein kinase C and Ca2+
Authors: Liu Hui‐Sheng , Hu Zhi‐Tao , Zhou Ke‐Ming , Jiu Ya‐Ming , Yang Hua , Wu Zheng‐Xing , Xu Tao
Published: February 2006

Modulation of the Ca2+ sensitivity and cooperativity of secretion is an important means of regulating neurotransmission and hormone secretion. Employing high‐time resolution measurement of membrane capacitance (Cm) stimulated by step‐like or ramp [Ca2+]i elevation, we have identified the co‐existence of both a high and low Ca2+‐sensitive exocytosis in an immortal pituitary gonadotrope cell line, LβT2. Ramp [Ca2+]i generated by slow uncaging elicited a biphasic Cm response. The first phase of response, which represents a highly Ca2+‐sensitive pool (HCSP) of vesicles, began to secrete at low [Ca2+]i concentration (<1 µM) with low Ca2+ cooperativity. In contrast, the second phase, which represents a lowly Ca2+‐sensitive pool (LCSP) of vesicles, only exocytozed at higher [Ca2+]i (>5 µM) and displayed a steep Ca2+ cooperativity. The co‐existence of vesicle populations with different Ca2+ sensitivities was further confirmed by flash photolysis stimuli. The size of the HCSP was ∼30 fF under resting conditions, but was dramatically increased (∼ threefold) by application of phorbol‐12‐myristate‐13‐acetate (PMA, an activator of protein kinase C). Forskolin (an activator of protein kinase A), however, exerted no significant effect on the size of both HCSP and LCSP. GnRH (gonadotropin releasing hormone) augmented the size of both pools to a larger extent (5‐ and 1.7‐fold increase for HCSP and LCSP, respectively). The heterogeneity of Ca2+ sensitivity from different pools of vesicles and its differential modulation by intracellular signals suggests that LβT2 cells are an ideal model to further unravel the mechanism underlying the modulation of Ca2+‐sensing machineries for exocytosis. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Evolved sex differences and occupational segregation
Authors: Browne Kingsley R.
Published: February 2006

Average sex differences in workplace outcomes are often assumed to be products of a malfunctioning labor market that discourages women from nontraditional occupations and a biased educational system that leaves women inadequately prepared for scientific and technical work. Rather than being a product purely of discriminatory demand, however, many sex differences in occupational distribution are at least partially a result of an imbalance in supply. Sex differences in both temperament and cognitive ability, which are products of our evolutionary history, predispose men and women toward different occupational behavior. The tendency of men to predominate in fields imposing high quantitative demands, high physical risk, and low social demands, and the tendency of women to be drawn to less quantitatively demanding fields, safer jobs, and jobs with a higher social content are, at least in part, artifacts of an evolutionary history that has left the human species with a sexually dimorphic mind. These differences are proximately mediated by sex hormones. Copyright © 2006 John Wiley & Sons, Ltd.
Hatching a plan: Developing leadership talent in emerging markets
Authors: Richman Hal , Wiggenhorn A. William
Published: February 2006

Emerging markets, which have a strong economic growth trajectory and market opportunity, are of great interest to large multinational corporations and other organizations with an international presence. But there is a lot of leadership talent waiting to be developed in these markets, and a lot of risk if this development doesn't occur. Here's a look at some actions that organizations operating in emerging markets can take to strengthen their leadership pools.
Multiple Morphologies and Their Transformation of a Polystyrene‐block‐poly(4‐vinylpyridine) Block Copolymer
Authors: Liu Libin , Gao Xiang , Cong Yong , Li Binyao , Han Yanchun
Published: February 2006

Summary: We report the multiple morphologies and their transformation of polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) in low‐alkanol solvents. In order to improve the solubility of polystyrene block in alcohol solvents, the solution of block copolymer sample was treated at a higher temperature, and then the influence of rate of decreasing temperature on multiple morphologies (including spheres, rods, vesicles, porous vesicles, large compound vesicles, and large compound micelles) was observed. The transformation of spheres to rods, to tyre‐shaped large compound micelles, and to sphere‐shaped large compound micelles was also realized. The formation mechanisms of the multiple morphologies and their transformation are discussed briefly.

Aggregates of PS‐P4VP formed in butanol by quenching from 110 °C to room temperature.

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Aggregates of PS‐P4VP formed in butanol by quenching from 110 °C to room temperature.
Hemicellulose Composition in the Outer Cell Wall Layers of Paper Grade and Dissolving Pulp
Authors: Freese Maren , Schmidt Ingeborg , Fischer Klaus
Published: February 2006

The hemicellulose content of pulp is dependent on different factors, such as the wood species, the conditions with cooking and bleaching harmonised with the application.

In addition to the hemicellulose content, a special interest for the valuation of pulp and the decision of arrangements of the production process is the hemicellulose distribution across the cell wall layers and the influence of several process stages on the hemicellulose distribution across the cell wall layers.

The investigations were carried out on dissolving pulp and paper grade pulp.

For paper grade pulp, the influence of separate bleaching steps and several bleaching sequences on the distribution of hemicellulose across the cell wall were investigated.

Regarding the selected dissolving pulps which were produced according to an acid bisulphite process and a pre‐hydrolysis sulphate process the influence of the cooking process on the hemicellulose distribution across the cell wall layers was of a special interest.
Carboxymethyl Xylan ‐ Control of Properties by Synthesis
Authors: Petzold Katrin , Schwikal Katrin , Günther Wolfgang , Heinze Thomas
Published: February 2006

The hemicellulose xylan is a polysaccharide that occurs in nature in enormous amount in various one year‐ and perennial plants having different structures and molecular masses. Versatile ways to generate bio‐based functional polymers result from the chemical modification of this biopolymer. In our research, xylans from various resources like birch‐, beech‐, and eucalyptus wood and from oat husk, rye bran, and corn cob were used to investigate the important method of carboxymethylation in detail. Different activation procedures were elaborated to synthesize carboxymethyl xylan. One step reactions lead to products with a degree of substitution (DS) from 0.13 to 1.22 in dependence on the molar ratio of anhydroxylose unit (AXU) to reagent. Two step syntheses yielded DS values up to 1.65. Carboxymethyl xylans are water soluble at a DS of 0.3. The solutions have different clearness depending on the provenience. NMR spectroscopy and HPL chromatography were applied to characterize the carboxymethyl xylans in detail.
Studies on the Film Formation of Polysaccharide Based Furan‐2‐Carboxylic Acid Esters
Authors: Hesse Stephanie , Liebert Tim , Heinze Thomas
Published: February 2006

Furan‐2‐carboxylic acid esters of xylan, cellulose, curdlan, dextran, and starch were synthesized and studied regarding their film formation abilities. The polysaccharide esters were utilized to prepare films of different appearance. To investigate supermolecular structures of the biopolymer derivatives, atomic force‐ and scanning electron microscopy were applied. The surface roughness and the macro‐pore size and ‐distribution of the polysaccharide ester films were characterized. Starch furan‐2‐carboxylic acid ester (starch furoate) did not show film formation. In contrast, dextran furoates are very well suitable for the surface coating of inorganic compounds while the xylan‐, cellulose‐, and curdlan derivatives yield self‐supporting films with different surface characteristics.
Xylans from Oat Spelts and Birch Kraft Pulp
Authors: Puls Jürgen , Schröder Nils , Stein Armin , Janzon Ron , Saake Bodo
Published: February 2006

Two different approaches for the isolation of xylan from hemicellulose‐rich sources have been investigated: Alkaline extraction from roller‐mill pretreated oat spelts and Nitren extraction of birch kraft pulp. For xylan recovery from oat spelts the experiments included extraction with 5% NaOH at 90 °C, followed by precipitation in methanol or 2‐propanol without neutralisation in order to facilitate NaOH recovery. A subsequent peroxide bleaching yielded a product of approximately 90% ISO brightness. The work on Nitren extraction of birch kraft pulp included the optimisation of the extraction process with regard to the Nitren charge. Nitren was much more specific in xylan extraction compared to Cuen, and up to 90% of the xylan content of the birch kraft pulp could be removed. It turned out that dried pulps were superior for this process compared to never‐dried pulps, since substantial cellulose proportions in never‐dried pulps were also mobilised by Nitren treatment. The properties of the recovered xylans from both processes were compared with regard to molar mass and substitution. It could be demonstrated that more or less intact arabinoxylans with molar masses of 30,000 g/mol could be obtained from oat spelts. The arabinoxylans contained 8–10 mol‐% arabinofuranose and 2 mol‐% 4‐O‐methylglucuronic acid substituents. Nitren extraction of a birch kraft pulp yielded xylans of 9,400 and 11,200 g/mol. Only traces of 4‐O‐methyl‐glucuronic‐ and hexenuronic acid substituents could be found.
Isolation, Synthesis and Derivatization of Xylodextrins
Authors: Abad‐Romero Beatriz , Haltrich Dietmar , Potthast Antje , Rosenau Thomas , Sixta Herbert , Kosma Paul
Published: February 2006

A series of xylodextrins has been produced by enzymatic or hydrothermal degradation of industrial xylans. For further synthetic use, the oligomers were converted into per‐O‐acetylated xylooligomers which were separated by silica gel chromatography to furnish preparative amounts of xylobiose up to xylopentaose. In a model reaction, selective anomeric deacetylation and treatment with trichloroacetonitrile furnished a xylobiosyl donor, which was converted into the β‐methyl glycoside. In addition, methyl β‐D‐xylopyranoside was transformed into a suitable glycosyl acceptor via tosylation followed by a double displacement reaction at O‐4, allowing for further chain elongation and modification at the reducing xylopyranosyl unit.
Xylo‐Oligosaccharide (XOS) Formation through Hydrothermolysis of Xylan Derived from Viscose Process
Authors: Griebl Alexandra , Lange Thomas , Weber Hedda , Milacher Walter , Sixta Herbert
Published: February 2006

Xylo‐oligosaccharides (XOS) have gained growing interest during the past decade owing to their beneficial influence on health. At the same time, a trend to a more effective utilization of biomass and biomass degradation products can be observed. As a consequence, also the steeping‐lye of the viscose process is discussed as a potential source of new products based on xylans, xylooligosaccharides, xylose, and different xylose degradation products, thus being a driving force for the development of appropriate production processes. Therefore, xylan isolated from the steeping‐lye was subjected to hydrothermal degradation for production of xylo‐oligosaccharides (XOS). The experiments were carried out at 120, 150, and 180 °C, respectively. This hydrothermal treatment led to a soluble fraction, consisting of neutral and acidic XOS, and an insoluble residue predominantly made up of highly crystalline cellulose. A mass balance was established to calculate the activation energy for hydrothermal xylan degradation from weight loss kinetics. The degree of polymerization (DP) of the neutral product fraction could be influenced in a wide range by the reaction conditions applied. Acidic XOS were further characterized using mass spectrometry (MS). A 4‐O‐methylglucuronic acid residue α‐(1,3)‐linked to the xylose backbone was detected as a new structural element in alkaline degradation products derived from beech wood xylan.
Kinesthesia is impaired in focal dystonia
Authors: Putzki Norman , Stude Philipp , Konczak Jürgen , Graf Karoline , Diener Hans‐Christoph , Maschke Matthias
Published: February 2006

Parkinson's disease (PD) and focal dystonia (FD) are both predominantly characterized by motor symptoms. Also, recent research has shown that sensory processing is impaired in both movement disorders. FD is characterized by involuntary movements and abnormal limb postures; thus, abnormal kinesthesia could be involved in the pathogenesis. We examined passive index finger movements in patients with FD (n = 12) and PD (n = 11) and in age‐matched healthy controls (n = 13). Compared to healthy controls, patients with PD and FD were significantly impaired in the correct detection of the movement direction. The perceptual thresholds for 75% correct responses of movement direction were 0.21 degrees for FD and 0.28 degrees for PD patients compared to 0.13 degrees in control subjects. Subjects with PD and FD were also significantly impaired when they had to judge consecutive amplitudes. Results of the present study point to impaired kinesthesia in FD. Defective sensory processing could be involved in the pathophysiology of the disease and may influence dystonic contractions. © 2006 Movement Disorder Society
Congenital disorder of glycosylation type Ia presenting as early‐onset cerebellar ataxia in an adult
Authors: Schoffer Kerrie L. , O'Sullivan John D. , McGill Jim
Published: February 2006

Congenital disorders of glycosylation (CDG) are a recently described, underrecognized group of syndromes characterized biochemically by abnormal glycosylation of serum and cellular glycoproteins. We report a previously undiagnosed adult male who presented with early‐onset cerebellar ataxia in the context of mental impairment, peripheral neuropathy, retinopathy, body dysmorphism, cardiomyopathy, and hypogonadism. Newly available screening and genetic testing confirmed the diagnosis as CDG type Ia. This case emphasizes that CDG should be considered as a differential diagnosis for adults with early‐onset cerebellar ataxia, particularly in those persons with the aforementioned features, and that undiagnosed cases of childhood ataxia may require reassessment now that testing is available. © 2006 Movement Disorder Society