bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Cochlear Function in Mice: Distortion‐Product Otoacoustic Emissions
Authors: Martin Glen K. , Stagner Barden B. , Lonsbury‐Martin Brenda L.
Published: February 2006

Distortion‐product otoacoustic emissions (DPOAEs) can be measured in the ear canal following the presentation of two tones. These emissions are generated by the outer hair cells (OHCs) of the inner ear and they are reduced or absent when the OHCs are damaged by, for example, exposure to excessive noise or ototoxic drugs. Consequently, DPOAEs provide a powerful and noninvasive means to assess the robustness of OHC function. A detailed method is described for measuring DPOAEs to assess cochlear function in mice. Recommendations are given for the required equipment and instructions are presented for setting up a DPOAE system. Also, a protocol is outlined for measuring DPOAEs in mice and troubleshooting tips are provided. Examples of data analysis procedures following noise exposure in mice are included, as well. These methods are not only applicable to mice, but can be performed using essentially all small laboratory animals.
Uses of Forward and Reverse Genetics in Mice to Study Gene Function
Authors: Argmann Carmen A. , Dierich Andree , Auwerx Johan
Published: February 2006

As the focus of human genetics shifts from Mendelian traits to complex diseases, a sophisticated genetic tool kit—with space for genetics (classical, molecular, statistical, and quantitative), metabolics, proteomics, bioinformatics, and mathematics—is required to elucidate their multifactorial traits and regulatory processes. Importantly, mouse resources optimized to study the actions of isolated genetic loci on a fixed background are insufficient on their own for studying intact polygenic networks and genetic interactions, and researchers must work in the context of experimental model systems that optimally mimic the genetic structure of human populations. The success of such phenogenomic approaches depend on the efficacy by which specific mutations (gene targeting) and variability (recombinant inbreeding) can be introduced into the mouse genome, and on the optimization of phenotyping analyses of the mutant mouse lines. This unit describes the basic genetic approaches used to in the study of mouse model systems.
Evaluation of Energy Homeostasis
Authors: Argmann Carmen A. , Champy Marie‐France , Auwerx Johan
Published: February 2006

Body mass and composition reflect the combined effects of three processes: energy intake, energy partitioning (storage), and energy expenditure. Energy is released from food as it is combusted to carbon dioxide and water, and is expended as heat and work within a cell. The energy stores, mainly in adipose tissue, represent the net balance between intake and expenditure. The methods outlined in this unit evaluate these three processes by measuring food intake and lipid absorption, body fat composition, and energy expenditure. Evaluation of food intake and fat mass is a useful first‐line phenotyping test indicating altered energy homeostasis. Evaluation of energy expenditure in this unit addresses obligatory basal energy expenditure (for performance of cellular and organ functions), as measured by indirect calorimetry. The combined results of these tests provide indications of the metabolic defects in a mouse model and help to identify molecular targets that cause these abnormalities.
Overview of Model Systems for the Analysis of Human Disease
Authors: Lind Joanne , Semsarian Christopher
Published: February 2006

The development of animal models of human disease has been crucial in elucidating normal organ biology and pathogenic mechanisms leading to disease states, and in the development of new therapeutic strategies to modify disease. This unit provides an overview of various animal models used in the study of human disease and the factors that need to be considered when selecting a suitable animal model appropriate for the disease under investigation.
Thermophoresis of an aerosol sphere perpendicular to two plane walls
Authors: Keh Huan J. , Chang Yu C.
Published: February 2006

The problem of the thermophoretic motion of a spherical particle in a gaseous medium situated at an arbitrary position between two infinite parallel plane walls is studied theoretically in the quasisteady limit of negligible Peclet and Reynolds numbers. The imposed temperature gradient is uniform and perpendicular to the plane walls. The Knudsen number is assumed to be small so that the fluid flow is described by a continuum model with a temperature jump, a thermal slip, and a frictional slip at the particle surface. The presence of the confining walls causes two basic effects on the particle velocity: first, the local temperature gradient on the particle surface is altered by the walls, thereby speeding up or slowing down the particle; second, the walls enhance the viscous retardation of the moving particle. A boundary collocation method is used to solve the thermal and hydrodynamic governing equations of the system. Numerical results for the thermophoretic velocity of the particle relative to that under identical conditions in an unbounded gaseous medium are presented for various cases. The collocation results agree well with the available approximate analytical solutions obtained by using a method of reflections. The presence of the walls can reduce or enhance the particle velocity, depending upon the relative thermal conductivity and surface properties of the particle as well as the relative particle‐wall separation distances. The boundary effect on thermophoresis of a particle normal to two plane walls is found to be quite significant and generally stronger than that parallel to the confining walls. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Multitasking by Multivalent Circular DNA Aptamers
Authors: Di Giusto Daniel A. , Knox Sarah M. , Lai Yuching , Tyrelle Gregory D. , Aung May T. , King Garry C.
Published: February 2006

Nucleic acid aptamers are finding increasing applications in biology, especially as therapeutic candidates and diagnostic components. An important characteristic in meeting the needs of these applications is improved stability in physiological fluids, which is most often accomplished with chemical modification or unnatural nucleotides. In an alternative approach we have specified the design of a multivalent circular DNA aptamer topology that encompasses a number of properties relevant to nucleic acid therapeutic candidates, especially the ability to multitask by combining different activities together within a modular structure. Improved stability in blood products, greater conformational stability, antidoting by complementary circular antiaptamers, heterovalency, transcription factor decoy activity and minimal unintended effects upon the cellular innate immune response are desirable properties that are described here. Multitasking by circular DNA aptamers could similarly find applications in diagnostics and biomaterials, where the combination of interchangeable modules might generate new functions, such as anticoagulation coupled with reversible cell capture as, described here. These results provide a platform for further exploration of multivalent circular aptamer properties, especially in novel combinations of nucleic acid therapeutic modes.
Novel apoptosis assay to analyze immunosuppression
Authors: Boldt Andreas , Barten Markus Johannes , Weiss Claudia , Sagner Anja , Mohr Friedrich Wilhelm , Gummert Jan Fritz
Published: February 2006

Background

We developed a novel whole blood assay to assess the effects of immunosuppressants on lymphocyte apoptosis.

Methods

Peripheral blood for six experiments for each drug was treated either with cyclosporin A (CsA), mycophenolate acid (MPA), tacrolimus (TRL) or rapamycin (RAPA). Whole blood was stimulated with different concentrations of staurosporine (0–5 μM) for 24 h. Using FACS, apoptosis were measured by Annexin V expression (%cells ± SEM).

Results

MPA, RAPA, TRL, but not CsA, increased (P < 0.05) apoptotic cells (MPA:20.9 ± 3.7; RAPA:17.5 ± 3.3; TRL:16.4 ± 2.9 vs. control:15.2 ± 2.8).

Conclusion

This new whole blood assay exhibited that MPA has a stronger effect on apoptosis than RAPA and TRL, whereas CsA had no effect. © 2006 International Society for Analytical Cytology
Flow cytometric analysis of the in situ hybridization of cyclooxygenase isoforms in mesangial cells treated with cyclosporine A
Authors: de Hornedo J. Pérez , Fernández M. Calvino , de la Fuente G. de Arriba , Fernández P. del Reino , Cid T. Parra , Martinez S. Benito
Published: February 2006

Background

Cyclosporine A increases oxidative stress in kidney and we hypothesized that cyclooxygenase (COX) may be involved in this effect.

Material and Methods

Mesangial cells of Cyclosporine A‐treated (4, 7 or 10 days) rats were obtained to evaluate mRNA expression of COX‐isoforms (COX‐1, constitutive and COX‐2, inducible) by “in situ” hybridization. Probes were labelled using “Gene Image Random Prime Labelling Protocol” and COX expression was measured by flow cytometry.

Results and Discussion

“In situ” hybridization by flow cytometry is an useful method to detect mRNA. We observed an increased COX‐2 expression in a time‐dependent manner in parallel with Reactive Oxygen Species synthesis. COX‐1 expression increased only at 10 days. © 2006 International Society for Analytical Cytology
Microfluorometry of cell membrane dynamics
Authors: Weber Petra , Wagner Michael , Schneckenburger Herbert
Published: February 2006

Membranes of living cells are characterized by a combination of conventional and total internal reflection fluorescence microscopy (TIRFM) using the membrane marker laurdan. In the first case, all cellular membranes are assessed simultaneously, whereas in the second case, the plasma membrane is excited selectively by the evanescent electromagnetic field of a laser beam. A spectral shift depending on the phase of membrane lipids is used to characterize membrane stiffness, which decreases with temperature and increases with the amount of cholesterol. Spectral properties are evaluated and displayed as microscopic images. © 2006 International Society for Analytical Cytology
Function of indoleamine 2,3‐dioxygenase in corneal allograft rejection and prolongation of allograft survival by over‐expression
Authors: Beutelspacher Sven C. , Pillai Radhakrishna , Watson Martin P. , Tan Peng H. , Tsang Julia , McClure Myra O. , George Andrew J. T. , Larkin Daniel F. P.
Published: February 2006

Indoleamine 2,3‐dioxygenase (IDO) suppresses T cell responses by its action in catabolising tryptophan. It is important in maintenance of immune privilege in the placenta. We investigated the activity of IDO in the cornea, following corneal transplantation and the effect of IDO over‐expression in donor corneal endothelium on the survival of corneal allografts. IDO expression was analysed and functional activity was quantified in normal murine cornea and in corneas following transplantation as allografts. Low levels of IDO, at both mRNA and protein levels, was detected in the normal cornea, up‐regulated by IFN‐γ and TNF. Expression of IDO in cornea was significantly increased following corneal transplantation. However, inhibition of IDO activity in vivo had no effect on graft survival. Following IDO cDNA transfer, murine corneal endothelial cells expressed functional IDO, which was effective at inhibiting allogeneic T cell proliferation. Over‐expression of IDO in donor corneal allografts resulted in prolonged graft survival. While, on one hand, our data indicate that IDO may augment corneal immune privilege, up‐regulated IDO activity following cytokine stimulation may serve to inhibit inflammatory cellular responses. While increasing IDO mRNA expression was found in allogeneic corneas at rejection, over‐expression in donor cornea was found to significantly extend survival of allografts.
A very rapid and simple assay based on trogocytosis to detect and measure specific T and B cell reactivity by flow cytometry
Authors: Puaux Anne‐Laure , Campanaud Julie , Salles Audrey , Préville Xavier , Timmerman Benedikt , Joly Etienne , Hudrisier Denis
Published: February 2006

Detection, quantification, separation and characterization of T and B cells reactive to specific antigens are important tasks in both basic and clinical immunology. Here, we describe an approach allowing the performance of all four tasks on a functional basis by flow cytometry. The assay is based on the property of lymphocytes to capture membrane components from the cells they interact with, in a process we call trogocytosis. Working with CD8+ CTL and target cells labeled with membrane markers, we describe the conditions allowing reactive lymphocytes to be detected rapidly and inexpensively within mixed populations. Accordingly, we used this method to monitor the CTL response triggered in mice after vaccination. In addition, we documented the applicability of this method to the detection of antigen‐specific CD4+ T and B cells. While our method is, for the time being, not as sensitive as staining of CTL with MHC class I multimers, it allows the simultaneous quantitative identification of reactive CD8+, CD4+ and B cells. Altogether, our method offers a simple and general alternative to other methods previously described to detect and quantify lymphocyte reactivity, and it can also be used in combination with those.
Ikaros has a crucial role in regulation of B cell receptor signaling
Authors: Nera Kalle‐Pekka , Alinikula Jukka , Terho Perttu , Narvi Elli , Törnquist Kid , Kurosaki Tomohiro , Buerstedde Jean‐Marie , Lassila Olli
Published: February 2006

The transcription factor Ikaros, a key regulator of hematopoiesis, has an essential role in lymphocyte development. In mice, fetal lymphoid differentiation is blocked in the absence of Ikaros, and whereas T cells develop postnatally, B cells are totally absent. The significance of Ikaros in the B cell development is evident, but how Ikaros regulates B cell function has neither been established nor previously been studied with B cells that lack Ikaros expression. Here we show that disruption of Ikaros in the chicken B cell line DT40 induces a B cell receptor (BCR) signaling defect with reduced phospholipase Cγ2 phosphorylation and impaired intracellular calcium mobilization, which is restored by Ikaros reintroduction. Furthermore, we show that lack of Ikaros induces hyperphosphorylation of Casitas B lymphoma protein subsequent to BCR activation. These results indicate that the absolute need of Ikaros for development, cell fate decisions and maintenance of B cells is due to the enhancement of BCR signaling.
N–H···S Hydrogen Bonds in a New Family of Ion‐Pair Complexes Between Cationic Nickel Tetraazabicyclononane and Anionic Metal Dithiolates: Synthesis, Characterization and Properties of [Ni(C9H22N6)][M(mnt)2](MII = Cu, Ni, Pd)
Authors: Madhu Vedichi , Das Samar K.
Published: February 2006

The ion‐pair complexes [Ni(C9H22N6)][Cu(mnt)2] (1), [Ni(C9H22N6)][Ni(mnt)2] (2), and [Ni(C9H22N6)][Pd(mnt)2] (3; mnt2– = 1,2‐dicyanoethylenedithiolate, C9H22N6 = 3,7‐bis(2‐aminoethyl)‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane) have been synthesized and characterized by elemental analysis, IR, UV/Vis, and 1H NMR spectroscopy, X‐ray powder diffraction, and electrochemical studies, and unambiguously by single‐crystal X‐ray crystallography. All three complexes are isostructural and crystallize in the monoclinic space groupP21/n. The N–H···S‐type hydrogen‐bonding capabilities of the classical sulfur‐containing complex anions [MII(mnt)2]2– (A; M = Cu, Ni and Pd) have been explored using amine groups containing the nickel complex cation [Ni(C9H22N6)]2+ (C) in the ion‐pair compounds 1, 2, and 3. In the crystal, the cation interacts with two different anions through three N–H···S hydrogen bonds and, likewise, the anion is hydrogen‐bonded to two different cations through three hydrogen bonds, resulting in the formation of a chain‐like arrangement. The average N–H···S hydrogen‐bond lengths are 3.498(3), 3.505(3), and 3.490(5) Å for compounds 1, 2, and 3, respectively. Another crystallographic feature is the presence of CC–AA–CC–AA‐type packing with short S···Ni contacts in the crystal structures. Besides crystallography, the existence of these N–H···S hydrogen bonds between cation [Ni(C9H22N6)]2+ (C) and anion [MII(mnt)2]2– (A) is strongly supported by the IR and 1H NMR studies. The stability of the [Ni(C9H22N6)]2+ (C) moiety in compounds 1, 2, and 3 is discussed in light of electrochemical studies performed on these compounds and [Ni(C9H22N6)](ClO4)2. Complex 1 exhibits a well‐resolved ESR signal corresponding to a Cu2+ (d9) system at liquid‐nitrogen temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
An Electron Microscopy Study of New Chemically Twinned Phases in the MgS‐Yb2S3 System
Authors: Urones‐Garrote Esteban , Gómez‐Herrero Adrián , Landa‐Cánovas Ángel R. , Otero‐Díaz L. Carlos
Published: February 2006

Four new phases in the MgS‐Yb2S3 system have been identified and characterised by means of transmission electron microscopy and associated techniques, such as microdiffraction and X‐ray energy dispersive spectroscopy analysis. The observed stoichiometries are: MgYb2S4 [a = 0.3752(2), b = 1.259(1), c = 1.268(2) nm] and Mg2Yb6S11 [a = 0.37297(4), b = 1.2592(2), c = 3.4853(3) nm] with orthorhombic symmetry (space group Cmcm) and Mg3Yb8S15 [a = 1.2637(1), b = 0.37176(5), c = 2.4132(2) nm; β = 100.40(1)°] and MgYb4S7 [a = 1.2578(2), b = 0.3735(3), c = 1.1417(7) nm; β = 104.88(6)°] with monoclinic symmetry (space group C2/m). Their structures can be described and derived from the NaCl‐type by the crystallographic operation of chemical twinning at the unit‐cell level along the {113}NaCl planes. The a and b lattice parameters are common in all the structures while the cparameter depends on the total extension of the twin slabs’ sequence, n, such that c ≈ n × d(113)MgS (for orthorhombic phases) or d(001) ≈ n × d(113)MgS (for monoclinic phases). All the unit‐cell parameters were refined from the X‐ray powder diffraction data after the unit‐cell symmetries had been deduced from electron microscopy data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Peroxynitrite/Nitric Oxide Balance in Ischemia/Reperfusion Injury‐Nanomedical Approach
Authors: Kubant Ruslan , Malinski Christopher , Burewicz Andrzej , Malinski Tadeusz
Published: February 2006

Electrochemical nanosensors were used to simultaneously monitor in vitro (a single endothelial cell) and in vivo (vasculature of rat) the concentrations of NO (vasorelaxant), cytotoxic O$\rm{ {_{2}^{-}}}$ (oxidative stress) and ONOO− (nitroxidative stress). A balance of [NO]/[ONOO−]=(K) was applied as the diagnostic marker of dysfunctional endothelium and cardiovascular disease. In the isolated endothelium of normotensive rats, K= 2.8±0.1 while in hypertensive rats, K=0.4±0.1. During ischemia, K dropped from 7±1 to 1.4±0.2 and further decreased to 0.05±0.01 during reperfusion. The edema and vasoconstriction, indicators of vascular injury, correlated directly with the decrease in K.
Astrocyte heterogeneity revealed by expression of a GFAP‐LacZ transgene
Authors: Lee Youngjin , Su Mu , Messing Albee , Brenner Michael
Published: February 2006

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein present primarily in astrocytes. The gene is first expressed as astrocytes mature, and in the adult is strongly upregulated in response to CNS damage. Thus, in addition to its astrocyte specificity, transcriptional regulation of the GFAP gene is of interest as a reporter of CNS signaling during development and injury. Several laboratories have shown that approximately 2 kb of 5′‐flanking DNA of the human or mouse GFAP gene is sufficient to direct transgene expression to astrocytes and to confer developmental and injury‐induced regulation. Enhancer regions have been identified adjacent to the basal promoter and about 1500 bp upstream of the RNA start site. Juxtaposition of these two segments yielded a 447 bp promoter, gfa28, which strongly drove reporter activity in transfected glioma cells. We report here that in mice a gfa28‐lacZ transgene expresses in only certain brain regions, revealing an unexpected heterogeneity among astrocytes. The restricted pattern of expression is present early in development, is not altered by injury, and is preserved in cultured astrocytes. However, astrocytes cultured from an inactive region strongly express a transiently transfected gfa28‐lacZ construct, and activity of the embedded gfa28‐lacZ transgene is partially restored by treatment with a histone deacetylase inhibitor. These results indicate that the absence of gfa28‐lacZ expression in specific brain regions results from a developmental failure to remodel GFAP chromatin to an open structure. Thus, expression of the gfa28‐lacZ transgene appears to serendipitously mark a distinct set of astrocyte precursors. © 2006 Wiley‐Liss, Inc.
Blockade of PD‐L1 (B7‐H1) augments human tumor‐specific T cell responses in vitro
Authors: Blank Christian , Kuball Juergen , Voelkl Simon , Wiendl Heinz , Becker Bernd , Walter Bernhard , Majdic Otto , Gajewski Thomas F. , Theobald Mathias , Andreesen Reinhard , Mackensen Andreas
Published: February 2006

Human tumors frequently escape immune destruction, despite the presence of cyototoxic T cells (CTL) recognizing tumor‐associated antigens (TAA). We have previously shown that programmed death ligand‐1 (PD‐L1), a recently identified ligand of the B7 superfamily, is expressed on murine tumors and can inhibit antitumor immune responses. To evaluate the clinical relevance of our animal model findings, we examined human tumors and tumor‐specific T cells. We found PD‐L1 to be constitutively expressed on human renal cell carcinoma (RCC) cell lines and upregulated on human melanoma cell lines upon exposure to interferon‐gamma. Similarly, we found binding of anti‐PD‐L1 monoclonal antibody (mAb) on frozen sections from RCC and melanomas, but not on normal tissues. The corresponding inhibitory receptor of PD‐L1, PD‐1, revealed a higher expression on tumor‐infiltrating lymphocytes than on peripheral blood lymphocytes (PBL) from melanoma patients upon specific antigen stimulation. Stimulation of PBL from healthy donors with peptide‐loaded dendritic cells in the presence of anti‐PD‐L1 mAb altered neither the total T cell numbers after expansion, nor the percentage of peptide‐specific CTL, when providing a T cell help by addition of cytokines. However, when stimulating TAA‐specific CTL and T helper cells with Ag‐pulsed dendritic cells in the absence of exogenous cytokines, PD‐L1 blockade increased the cytokine production. Similar to the data achieved in the murine system, the blockade of PD‐L1 on human tumors resulted in enhanced cytolytic activity of TAA‐specific CTLs and cytokine production of TAA‐specific T helper cells when interacting directly with the tumor. In summary, our data suggest that PD‐L1/PD‐1 interactions negatively regulate T cell effector functions predominately in the absence of exogenous cytokine support, indicating an important role for this pathway in tumor evasion. © 2006 Wiley‐Liss, Inc.
Picophytoplankton contribution to phytoplankton community structure in the Gulf of Venice (NW Adriatic Sea)
Authors: Aubry Fabrizio Bernardi , Acri Francesco , Bastianini Mauro , Pugnetti Alessandra , Socal Giorgio
Published: February 2006

The size distribution of the phytoplankton community has been analyzed on a monthly basis in the Gulf of Venice (NW Adriatic Sea), with the aim to assess the seasonal variation of the contribution of autotrophic picoplankton (APP) to total phytoplankton. The investigation was carried out in two stations characterized by different influences of fluvial inputs. APP was mainly made up of Synechococcus , the larger fraction (Utermöhl Fraction Phytoplankton, UFP: µm as maximum linear dimension) of diatoms and nanoflagellates. The average APP abundance (46 × 103 cells ml–1) and biomass (8.1 µg C dm–3) indicate that APP was a persistent and significant component of the NW Adriatic phytoplankton. The highest APP abundance (up to 270 × 103 cells ml–1) and biomass (up to 49 µg C dm–3) were recorded from summer to autumn, UFP peaked from late winter to late spring. The mean APP contribution to total phytoplankton abundance and biomass was 98% and 31% respectively.

The seasonal variation of total phytoplankton biomass was mainly driven by the UFP fraction; however, a seasonal shift in the relative importance of UFP and APP occurred from spring to summer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Regulation of Rotifer Community by Predation of Cyclops vicinus (Copepoda) in the Římov Reservoir in Spring
Authors: Devetter Miloslav , Seďa Jaromír
Published: February 2006

The structuring role and predation impact of Cyclops vicinus on the rotifer community was studied using in situ enclosure experiments in Římov Reservoir during the spring of 2000. Seasonal changes in abundance and birth rates of the rotifer species Synchaeta lakowitziana , Polyarthra spp., Keratella cochlearis and Kellicottia longispina were related to predation pressure, i.e. selectivity and cropping rates of C. vicinus . All four rotifer species were found to be consumed by C. vicinus whose predation rates showed a marked succession through the spring period and corresponded to changes in the relative abundance of the pelagic species. The highest predation rates exhibited by C. vicinus were on Synchaeta lakowitziana and Polyarthra spp., being 11.3 and 6.4 ind Cyclops –1 day–1 respectively. The activity of the predator switched among three types of preferred food during the spring period. The most preferred, Synchaeta, was replaced by Polyarthra after Synchaeta became extinct and these species were replaced by Keratella when both soft‐bodied forms were not available in sufficient quantities. Loricated species (K. cochlearis and K. longispina) were consumed at a slower rate. We calculated the proportion of rotifer production cropped day–1 in order to estimate the predation impact of C. vicinus , which ranged from 11.6 to more than 100% over time and rotifer species. This shows that relative predation impact can be high not only on species most strongly selected, but also on species which are not selected. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Study of the Decomposition of Reed (Phragmites australis ) as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes
Authors: V.‐Balogh Katalin , Présing Mátyás , Vörös Lajos , Tóth Noémi
Published: February 2006

The decomposition of leaf and steam litter of reed (P. australis) was measured both in the field and in the laboratory. The breakdown rates, the total carbon and the stable carbon isotope dynamics of reed litter were determined. The stable carbon isotope ratios of isolated humic substances (fulvic and humic acids) were also analysed. The δ13C value in reed remains increased from –26‰ to –24‰ for stems and from –27‰ to –26‰ for leaves. The dissolved fulvic and humic acids isolated from the experimental bottles (mean δ13C was –27.6‰) and the reservoir water were depleted in 13C (mean δ13C was –28.6‰) relative to the reed remains. The results show that reed litter is an important source of coloured aquatic humic substances. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Occurrence of Arbuscular Mycorrhizas and Dark Septate Endophytes in Hydrophytes from Lakes and Streams in Southwest China
Authors: Kai Wang , Zhiwei Zhao
Published: February 2006

In this study, the colonization of arbuscular mycorrhizas (AM) and dark septate endophytes (DSE) in 140 specimens of 32 hydrophytes collected from four lakes and four streams in southwest China were investigated. The arbuscular mycorrhizal fungi (AMF) and DSE colonization in these hydrophytes were rare. Typical AM structures were observed in one of the 25 hydrophytic species collected in lakes and six of the 17 species collected in streams.

Spores of 10 identified AMF species and an unidentified Acaulospora sp. were isolated from the sediments. The identified AMF came from the four genera, Acaulospora, Gigaspora, Glomus and Scutellospora . Glomus and G. mosseae were the dominant genus and species respectively in these aquatic environments.

The presence of DSE in hydrophytes was recorded for the first time. DSE occurred in one of the 25 hydrophyte species collected in lakes and three of the 17 species collected in streams. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Do Invertebrate Activity and Current Velocity Affect Fungal Assemblage Structure in Leaves?
Authors: Ferreira Verónica , Graça Manuel A. S.
Published: February 2006

In this study we assessed the effect of current velocity and shredder presence, manipulated in artificial channels, on the structure of the fungal assemblage colonizing alder (Alnus glutinosa(L.)Gaertner) leaves incubated in coarse and fine mesh bags. Fungal sporulation rates, cumulative conidial production and number of species of aquatic hyphomycetes were higher in leaves exposed to high rather than to low current velocity. The opposite was observed regarding Simpson's index (D) on the fungal assemblage. Some species of aquatic hyphomycetes were consistently stimulated in high current channels. No effect of shredders or of mesh type was observed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Glycosaminoglycan degradation reduces mineralized tissue–titanium interfacial strength
Authors: Nakamura Hiromi , Shim Jaewoo , Butz Frank , Aita Hideki , Gupta Vijay , Ogawa Takahiro
Published: February 2006

Although the localization of the proteoglycan/glycosaminoglycan (GAG) complex at the bone–titanium implant interface has been implied, the role of proteoglycans on the establishment of bone–titanium integration is unknown. The hypothesis to be tested was that proteoglycans play an important role in establishing bone–titanium interfacial adhesion. The objective of this study is to investigate the effect of proteoglycan knockdown by GAG enzymatic degradation on the interfacial strength between mineralized tissue and titanium having different surface topographies. Rat bone marrow‐derived osteoblastic cells were cultured on either a machined titanium disk or an acid‐etched titanium disk. At day 21 of culture, one of the three following GAG degradation enzymes was added into the culture; chondroitinase AC, chondroitinase B, or keratanase. After 3 days of incubation (at day 24 of culture), the laser spallation technique was applied to the samples in order to assess the tissue–titanium interfacial strength. In this technique, a laser‐generated stress wave is used to separate the tissue–titanium interface, and the interfacial strength is determined interferometrically by recording the transient free surface velocity of the tissue. Mineralized tissue cultured on the acid‐etched titanium showed 20–30% higher tissue interfacial strength than that cultured on the machined titanium (p < 0.0001). For both the machined and acid‐etched surface cultures, administration of the enzyme reduced the interfacial strength by 25–30% compared with the untreated control cultures (p < 0.0001). There were no differences in the effect among the three different enzymes tested. A nanoindentation study revealed that the enzyme treatment did not affect the elastic modulus of the mineralized tissue. Scanning electron microscopic and energy dispersive spectroscopic analyses revealed less post‐spallation tissue remnant on the titanium substrates when treated with the enzymes. The tissue remnant was greater in amount on the acid‐etched surface than on the machined surface. The results suggest that there exists not only mechanical interlocking but also biological interfacial adhesion between the mineralized tissue and titanium, in which the proteoglycan/GAG complex is involved. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
The effects of titanium and polymethylmethacrylate particles on osteoblast phenotypic stability
Authors: Ramachandran R. , Goodman S.B. , Smith R.L.
Published: February 2006

Wear particles generated following total joint arthroplasty interact with cells at the periprosthetic margin and induce an inflammatory response that contributes to osteolysis, aseptic loosening, and implant failure. This study examined the long‐term effects of particles from two commonly implanted materials, titanium (Ti) and polymethylmethacrylate (PMMA), on cell viability and metabolism over a 21‐day time course, using the human osteoblast‐like cell line MG‐63. Addition of particles was not associated with increased cell death or nitric oxide production at the particle concentration chosen. Collagen production was increased with exposure to titanium particles, whereas alkaline phosphatase and osteocalcin expression remained unchanged following exposure to both types of particles. The data show that titanium but not PMMA particles shifts bone cell metabolism to preferentially produce fibrous tissue rather than bone. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Immobilized rhBMP‐2/succinylated type I atelocollagen gene expression of intracellular signaling molecules on ST2 cells
Authors: Tsujigiwa Hidetsugu , Nagatsuka Hitoshi , Lee You Jin , Han Phuu Pwint , Gunduz Mehmet , LeGeros Racquel Z. , Inoue Masahisa , Yamada Masao , Nagai Noriyuki
Published: February 2006

Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) chemically‐bonded to succinylated type I atelocollagen, a biomaterial carrier with a porous structure, was reported to augment cellular activity of ST2 cells. The Smad protein family has been suggested to play an important role in the intracellular signaling pathway of BMP by its binding to receptors on target cells. However, there has been no study analyzing the downstream genes of the rhBMP‐2 induced intracellular signal transduction pathway. The purpose of this study was to examine the effect of immobilized rhBMP‐2 on gene expression of intracellular signaling molecules on ST2 cells. Our study showed two expression patterns of downstream genes of rhBMP‐2 intracellular signal transduction pathway. In the first pattern, BMPR‐IA, Smad 1, and Smad 5 genes showed high basic expression before the addition of rhBMP, and the high level of gene expression continued for long period and decreased in the late stage when rhBMP‐2 was immobilized. In the second pattern, Smad 6, Smad 7, and Smad 8 genes showed low basic expression before the addition of rhBMP‐2 and a continuous increase from the beginning was followed by a decrease in the late stage when rhBMP‐2 was immobilized. Our results also showed that intracellular signaling continued for prolonged period when rhBMP‐2 was immobilized to succinylated type I atelocollagen. This study indicated that immobilizing rhBMP‐2 is an efficient method to increase bone induction. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
An evaluation of a general circulation model (GCM) and the NCEP–NCAR reanalysis data for winter precipitation in Greece
Authors: Tolika K. , Maheras P. , Flocas H. A. , Arseni‐Papadimitriou A.
Published: February 2006

In this study, an attempt is made to evaluate winter precipitation data derived from the general circulation model (GCM)—HadAM3P (atmospherical circulation model—Hadley Center) and from the National Center for Environmental Prediction–National Center of Atmospheric Research (NCEP–NCAR) reanalysis project for the period 1960–1990. These data sets are compared on a seasonal basis (winter) with observational data derived from stations over Greece. More specifically, the suitability of their average distributions and their spatial and temporal variability is examined. The methods used are principal component analysis (PCA) and canonical correlation analysis (CCA). The connection between the precipitation data sets and five cyclonic circulation types, from a daily catalogue, is also studied. With respect to the spatial distribution of the mean precipitation amounts, NCEP data show better agreement with the observational data compared to the modeled data. However, both NCEP and HadAM3P values are generally underestimated. Moreover, it seems that the HadAM3P is able to capture and reproduce quite satisfactorily the relationship between the precipitation data and the circulation types, but inadequately simulates the impact of orography and the Aegean Sea. Finally, the links between the precipitation variability in Greece and the European 500 hPa variability given by CCA seem to be fairly well reproduced by the model. Copyright © 2006 Royal Meteorological Society
Quantitative liver function tests in donors and recipients of living donor liver transplantation
Authors: Jochum Christoph , Beste Mechthild , Penndorf Volker , Farahani Marjan Sharifi , Testa Giuliano , Nadalin Silvio , Malago Massimo , Broelsch Christoph E. , Gerken Guido
Published: February 2006

The unique ability of the liver to regenerate quickly after resection makes living donor liver transplantation (LDLT) possible. This technique uses the unique ability of the liver to regenerate to full size after partial resection. However, the quality and course of this regeneration process in humans are still widely unexplored. In the present study we investigated the quantitative liver function tests galactose elimination capacity (GEC), indocyanine green half-life (ICG), and lidocaine half-life as markers for the quality of the liver regeneration in the first 3 months after LDLT. In this study, 22 consecutive living liver donors and their corresponding recipients were analyzed at baseline and at 10 and 90 days after LDLT. Six recipients lost their grafts during the study period. We compared donors and recipients at the different time points. After LDLT, GEC decreased (−42.6%) and ICG increased (+50.6%) significantly in donors. ICG and GEC remained significantly altered over 3 months in donors with an improvement between days 10 and 90 (GEC, +59.3%; ICG, −9.1%). ICG and GEC improved significantly in recipients between days 10 and 90 (ICG, −63.7%; GEC, +16.3%). The lidocaine half-life showed no significant changes. The donors had better test results and recovered faster than the recipients. In conclusion, after LDLT the parameters for liver capacity and flow remain altered in donors and recipients despite rapid volume growth.
Liver Transpl 12:544–549, 2006.

© 2006 AASLD.
Lack of benefit of pre-transplant locoregional hepatic therapy for hepatocellular cancer in the current MELD era
Authors: Porrett Paige M. , Peterman Heather , Rosen Mark , Sonnad Seema , Soulen Michael , Markmann James F. , Shaked Abraham , Furth Emma , Reddy Rajender K. , Olthoff Kim
Published: February 2006

The potential for disease progression in patients awaiting liver transplantation for hepatocellular carcinoma (HCC) has encouraged many centers to employ pre-transplant radiofrequency ablation or chemoembolization in an attempt to control tumor burden while patients are on the wait list. Despite general acceptance by the transplant community, few objective data demonstrate pre-transplant treatment efficacy or improved post-transplant outcomes in HCC patients listed with Model for End-Stage Liver Disease (MELD) exception points. To evaluate the utility of pre-transplant therapy in the current MELD era, we retrospectively compared 31 treated patients (T) with 33 untreated (U) controls. Study endpoints included patient and disease-free survival, tumor recurrence, explant tumor viability, and the ability of MRI to detect viable tumor after therapy. Both cohorts had similar demographic, radiographic, and pathologic characteristics, although untreated patients waited longer for transplantation [119 (U) vs. 54 (T) days after MELD assignment, (P = .05); range: 1 day to 21 months]. Only 20% of treated tumors demonstrated complete ablation (necrosis) as defined by histologic examination of the entire lesion. Only 55% of lesions with histologic viable tumor were detected by MRI after pre-transplant therapy. After 36 months of follow-up, there was no difference between the treated and untreated groups in overall survival (84 vs. 91%), disease free survival (74% vs. 85%), cancer recurrence (23% vs. 12%), or mortality from cancer recurrence (57% vs. 25%) (P > 0.1). In conclusion, viable tumor frequently persists after pre-transplant locoregional therapy, and neoadjuvant treatment does not appear to improve post-transplant outcomes in the current MELD era.
Liver Transpl 12:665–673, 2006.

© 2006 AASLD.
Optimisation and Application of Polyolefin Branch Quantification by Melt‐State 13C NMR Spectroscopy
Authors: Klimke Katja , Parkinson Matthew , Piel Christian , Kaminsky Walter , Spiess Hans Wolfgang , Wilhelm Manfred
Published: February 2006

Summary: Quantitative branch determination in polyolefins by melt‐state NMR has been investigated paying particular attention to sensitivity per unit time. Comparison of spectra obtained using spectrometers operating at 700, 500 and 300 MHz 1H Larmor frequency, with 4 and 7 mm MAS probeheads, showed that the best sensitivity was achieved at 500 MHz using a 7 mm 13C1H optimised high‐temperature probehead. For materials available in large quantities static melt‐state NMR, using large‐diameter detection coils at 300 MHz, was shown to produce comparable results to melt‐state MAS measurements in less time. Artificial line broadening, introduced by FID truncation, was reduced by the use of π pulse‐train heteronuclear dipolar‐decoupling. This decoupling method, when combined with a higher duty‐cycle, allowed for the whole FID to be acquired. Optimised methods have been applied to the characterisation of short‐chain branching (SCB) in polyethylene‐ and poly(propylene)‐co‐α‐olefins with varying comonomer incorporation. Long‐chain branch (LCB) concentrations of 8 branches per 100 000 CH2 were quantified for an industrial ‘linear’ polyethylene in 13 h, with a signal‐to‐noise ratio of 10 for the α branch site used. The use of J‐coupling mediated polarisation transfer techniques were also shown to be viable for branch quantification in the melt‐state.

An example of the time efficient quantification of very low branch contents in polyethylene using optimised 13C melt‐state NMR under magic‐angle spinning. Concentrations of 7–8 branches per 100 000 CH2 groups were determined in only 13 h.

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An example of the time efficient quantification of very low branch contents in polyethylene using optimised 13C melt‐state NMR under magic‐angle spinning. Concentrations of 7–8 branches per 100 000 CH2 groups were determined in only 13 h.
Surface Morphology Evolution of a Thin Polymeric Supramolecular Film by Tuning Interactions
Authors: Zhang Ping , Gao Junpeng , Li Binyao , Han Yanchun
Published: February 2006

Summary: A polymeric supramolecule consisting of symmetric polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP), dodecylbenzenesulfonic acid (DBSA), and 3‐pentadecylphenol (PDP) was formed by proton transfer and hydrogen bonding. The surface morphology of a thin film of the polymeric supramolecule has been investigated. The spherical PS microdomains embedded in a P4VP(DBSA)1.0(PDP)1.0 matrix are observed for the as‐cast film because the weight fraction, fcomb, of the P4VP(DBSA)1.0(PDP)1.0 blocks is much higher than that of PS as a result of the non‐covalent interactions of P4VP and DBSA and DBSA and PDP. Upon annealing the PS‐b‐P4VP(1:1)(DBSA)1.0(PDP)1.0 film at high temperatures, the hydrogen bonding between the DBSA and PDP diminishes, which leads to a change of overall morphology from an ordered sphere to a pitted structure.

AFM topographic image of a PS‐b‐P4VP(1:1)(DBSA)1.0(PDP)1.0 thin film.

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AFM topographic image of a PS‐b‐P4VP(1:1)(DBSA)1.0(PDP)1.0 thin film.
Structural Diversity and Application Potential of Hemicelluloses
Authors: Ebringerová Anna
Published: February 2006

Isolation and targeted modification of plant polysaccharides as well as characterization of their structural, molecular and functional properties represent an important research topic of the Institute of Chemistry, Slovak Academy of Sciences, in Bratislava. The presentation provides an overview about the occurrence, structural diversity and functional properties of hemicelluloses representing a diverse group of plant cell wall polysaccharides. They are grouped into xyloglycans, mannoglycans, xyloglucans, and mixed‐linkage β‐glucans. Based on own results as well as on reported data from other research groups, the structure—property relations of the hemicelluloses as well as the existing and potential applications of these polysaccharides are discussed.
Derivatization and Characterization of Xylan from Oat Spelts
Authors: Hettrich Kay , Fischer Steffen , Schröder Nils , Engelhardt Jürgen , Drechsler Ullrich , Loth Fritz
Published: February 2006

Xylan is the predominant hemicellulose component in the residues of annual plants, e.g., in oat spelts xylan amounts to 35–40% of the total mass. For our investigation xylan was separated through alkaline extraction of oat spelts. Our aim was to synthesize water‐soluble hemicellulose derivatives from oat spelts xylan preferably under heterogeneous conditions. Esterification was used for derivatization. The synthesises were optimised by variation of the temperature, reaction time and the molar ratios to achieve complete solubility, with good reproducibility and in good yields. Other modification possibilities and application areas of xylan from oat spelts could be proved.
Tissue distribution ofN‐acetyltransferase 1 and 2 catalyzing theN‐acetylation of 4‐aminobiphenyl andO‐acetylation ofN‐hydroxy‐4‐aminobiphenyl in the congenic rapid and slow acetylator Syrian hamster
Authors: Hein David W. , Doll Mark A. , Nerland Donald E. , Fretland Adrian J.
Published: February 2006

N‐acetyltransferase 1 (NAT1) and 2 (NAT2) enzymes catalyzing both deactivation (N‐acetylation) and activation (O‐acetylation) of arylamine carcinogens such as 4‐aminobiphenyl (ABP) were investigated in a Syrian hamster model congenic at theNAT2 locus. NAT2 catalytic activities (measured withp‐aminobenzoic acid) were significantly (P < 0.001) higher in rapid than slow acetylators in all tissues (except heart and prostate where activity was undetectable in slow acetylators). NAT1 catalytic activities (measured with sulfamethazine) were low but detectable in most tissues tested and did not differ significantly between rapid and slow acetylators. ABPN‐acetyltransferase activity was detected in all tissues of rapid acetylators but was below the limit of detection in all tissues of slow acetylators except liver where it was about 15‐fold lower than rapid acetylators. ABPN‐acetyltransferase activities correlated with NAT2 activities (r2 = 0.871;P < 0.0001) but not with NAT1 activities (r2 = 0.132;P > 0.05). Levels ofN‐hydroxy‐ABPO‐acetyltransferase activities were significantly (P < 0.05) higher in rapid than slow acetylator cytosols for many but not all tissues. TheN‐hydroxy‐ABPO‐acetyltransferase activities correlated with ABPN‐acetyltransferase activities (r2 = 0.695;P < 0.0001) and NAT2 activities (r2 = 0.521,P < 0.0001) but not with NAT1 activities (r2 = 0.115;P > 0.05). The results suggest widespread tissue distribution of both NAT1 and NAT2, which catalyzes bothN‐ andO‐acetylation. These conclusions are important for interpretation of molecular epidemiological investigations into the role ofN‐acetyltransferase polymorphisms in various diseases including cancer. © 2006 Wiley‐Liss, Inc.