bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of insulin‐producing cells from PDX‐1 gene‐modified human mesenchymal stem cells
Authors: Li Yanhua , Zhang Rui , Qiao Haifa , Zhang Heping , Wang Yunfang , Yuan Hongfeng , Liu Qinbin , Liu Daqing , Chen Lin , Pei Xuetao 
Published: January 2007

AbstractIslet cell replacement is considered as the optimal treatment for type I diabetes. However, the availability of human pancreatic islets for transplantation is limited. Here, we show that human bone marrow‐derived mesenchymal stem cells (hMSCs) could be induced to differentiate into functional insulin‐producing cells by introduction of the pancreatic duodenal homeobox‐1 (PDX‐1). Recombinant adenoviral vector was used to deliver PDX‐1 gene into hMSCs. After being infected with Ad‐PDX‐1, hMSCs were successfully induced to differentiate into insulin‐secreting cells. The differentiated PDX‐1+ hMSCs expressed multiple islet‐cell genes including neurogenin3 (Ngn3), insulin, GK, Glut2, and glucagon, produced and released insulin/C‐peptide in a weak glucose‐regulated manner. After the differentiated PDX‐1+ hMSCs were transplanted into STZ‐induced diabetic mice, euglycemia can be obtained within 2 weeks and maintained for at least 42 days. These findings validate the hMSCs model system as a potential basis for enrichment of human beta cells or their precursors, and a possible source for cell replacement therapy in diabetes. J. Cell. Physiol. 211: 36–44, 2007. © 2007 Wiley‐Liss, Inc.
ß‐adrenergic receptor agonists delay while antagonists accelerate epithelial wound healing: Evidence of an endogenous adrenergic network within the corneal epithelium
Authors: Pullar Christine E. , Zhao Min , Song Bing , Pu Jin , Reid Brian , Ghoghawala Shahed , McCaig Colin , Isseroff R. Rivkah 
Published: January 2007

AbstractWound healing is a complex and well‐orchestrated biological process. Corneal epithelial cells (CECs) must respond quickly to trauma to rapidly restore barrier function and protect the eye from noxious agents. They express a high level of ß2‐adrenergic receptors but their function is unknown. Here, we report the novel finding that they form part of a regulatory network in the corneal epithelium, capable of modulating corneal epithelial wound repair. ß‐adrenergic receptor agonists delay CEC migration via a protein phosphatase 2A‐mediated mechanism and decrease both electric field‐directed migration and corneal wound healing. Conversely, ß‐adrenergic receptor antagonists accelerate CEC migration, enhance electric field‐mediated directional migration, and promote corneal wound repair. We demonstrate that CECs express key enzymes required for epinephrine (ß‐adrenergic receptor agonist) synthesis in the cytoplasm and can detect epinephrine in cell extracts. We propose that the mechanism for the pro‐motogenic effect of the ß‐adrenergic antagonist is blockade of the ß2‐adrenergic receptor preventing autocrine catecholamine binding. Further investigation of this network will improve our understanding of one of the most frequently prescribed class of drugs. J. Cell. Physiol. 211: 261–272, 2007. © 2007 Wiley‐Liss, Inc.
From the laboratory bench to the patient's bedside: An update on clinical trials with mesenchymal stem cells
Authors: Giordano Antonio , Galderisi Umberto , Marino Ignazio R. 
Published: January 2007

AbstractMesenchymal Stem Cells (MSCs) are non‐hematopoietic multi‐potent stem‐like cells that are capable of differentiating into both mesenchymal and non‐mesenchymal lineages. In fact, in addition to bone, cartilage, fat, and myoblasts, it has been demonstrated that MSCs are capable of differentiating into neurons and astrocytes in vitro and in vivo. MSCs are of interest because they are isolated from a small aspirate of bone marrow and can be easily expanded in vitro. As such, these cells are currently being tested for their potential use in cell and gene therapy for a number of human diseases. Nevertheless, there are still some open questions about origin, multipotentiality, and anatomical localization of MSCs. In this review, we discuss clinical trials based on the use of MSCs in cardiovascular diseases, such as treatment of acute myocardial infarction, endstage ischemic heart disease, or prevention of vascular restenosis through stem cell‐mediated injury repair. We analyze data from clinical trials for treatment of osteogenesis imperfecta (OI), which is a genetic disease characterized by production of defective type I collagen. We describe progress for neurological disease treatment with MSC transplants. We discuss data on amyotrophic lateral sclerosis (ALS) and on lysosomal storage diseases (Hurler syndrome and metachromatic leukodystrophy). A section of review is dedicated to ongoing clinical trials, involving MSCs in treatment of steroid refractory Graft Versus Host Disease (GVHD); periodontitis, which is a chronic disease affecting periodontium and causing destruction of attachment apparatus, heart failure, and bone fractures. Finally, we will provide information about biotech companies developing MSC therapy. J. Cell. Physiol. 211: 27–35, 2007. © 2007 Wiley‐Liss, Inc.
Injury of skeletal muscle and specific cytokines induce the expression of gap junction channels in mouse dendritic cells
Authors: Corvalán Liliana A. , Araya Roberto , Brañes María C. , Sáez Pablo J. , Kalergis Alexis M. , Tobar Jaime A. , Theis Martin , Willecke Klaus , Sáez Juan C. 
Published: January 2007

AbstractDendritic cells (DCs) in culture express at least connexin43, a protein subunit of gap junctions, and form gap junction channels, which could be important for T‐cells activation. Here, we evaluated whether DCs express connexins in vivo and also to identify components of their microenvironment that regulate the functional expression of gap junctions. In vivo studies were performed in lymph nodes of mice under control conditions or after skeletal muscle damage. In double immunolabeling studies, connexin45 was frequently detected in DEC205+ DCs in lymph nodes of control animals, whereas connexin43 was rarely found in DCs. However, connexin43 was upregulated in DCs after skeletal muscle damage. Upregulation of connexin43 gene expression by tissue damage was also confirmed in mice carrying a β‐galactosidase reporter gene in a connexin43 allele. The effect of several cytokines on the expression of functional gap junctions between cultured DCs was also tested. Under control conditions, cultured DCs did not communicate via gap junctions. However, after treatment with keratinocyte‐conditioned medium or cytokine mixtures containing at least TNF‐α and IL‐1β, they became transiently coupled through a pathway sensitive to octanol, a gap junction blocker. Cellular coupling induced by effective cytokine mixtures was prevented by IL‐6. Single cytokines (TNF‐α, IL‐1β, IFN‐γ, or IL‐6) or other mixtures than the described above did not induce coupling via gap junctions. Increased levels of connexin43 and connexin45 protein and mRNA accompanied the appearance of cellular coupling. These studies provide demonstration of connexin expression and regulation by specific danger signals in DCs. J. Cell. Physiol. 211: 649–660, 2007. © 2007 Wiley‐Liss, Inc.
BMP‐2 promotes differentiation of osteoblasts and chondroblasts in Runx2‐deficient cell lines
Authors: Liu Tingjiao , Gao Yuhao , Sakamoto Kei , Minamizato Tokutaro , Furukawa Keizo , Tsukazaki Tomoo , Shibata Yasuaki , Bessho Kazuhisa , Komori Toshihisa , Yamaguchi Akira 
Published: January 2007

AbstractTo investigate the molecular mechanism underlying the differentiation of osteoblasts and chondroblasts, we established a clonal cell lines, RD‐C6, from Runx2‐deficient mouse embryos. RD‐C6 cells expressed almost undetectable levels of phenotypes related to osteoblast and chondroblast differentiation at basal culture condition, whereas treatment with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) or transduction of BMP‐2 by adenovirus effectively induced this cell line to express mRNA related to the differentiation of osteoblasts and chondroblasts including alkaline phosphatase, osteocalcin, and osterix. Transduction of Runx2 also induced the expression of these mRNA in RD‐C6 cells. BMP‐2 transduction increased expression levels of mRNA for Msx2 and Dlx5, but Runx2 transduction induced no significant increases in expression levels of these mRNA. Microarray analysis using RD‐C6 cells with or without rhBMP‐2 treatment demonstrated that BMP‐2 upregulated 66 genes including 13 transcription‐related molecules such as Id1, Id2, Id4, Hey1, Smad6, Smad7, and Msx2. To confirm bone and cartilage formation ability of RD‐C6 cells, we transplanted RD‐C6 cells into the peritoneal cavity of athymic mice using diffusion chambers with rhBMP‐2. RD‐C6 cells generated unmineralized cartilage but not bone. These results indicate that BMP‐2 induces Runx2‐deficient cells to express markers related to osteoblast and chondroblast differentiation using a Runx2‐independent pathway, but it failed to induce these cells to differentiate into bone‐forming osteoblasts and mature chondrocytes. J. Cell. Physiol. 211: 728–735, 2007. © 2007 Wiley‐Liss, Inc.
Preliminary studies on the effect of processing on the IgE reactivity of tomato products
Authors: Germini Andrea , Paschke Angelika , Marchelli Rosangela 
Published: January 2007

AbstractTomatoes and tomato products, obtained from a market, from companies or prepared in research laboratories, were tested in order to investigate how different processes could modulate the IgE reactivity of these products. The protein fraction of the samples was extracted by using a low‐temperature method in order to avoid degradation, and then separated on SDS PAGE to evaluate the protein profile. All the separated samples were blotted onto nitrocellulose membranes and then individually tested with pooled human sera that had been obtained from patients allergic to tomato, in order to evaluate the potential IgE binding of the protein bands. Heat treatments conventionally employed for the production of tomato‐based products were found to strongly degrade proteins thus dramatically reducing their IgE reactivity; characteristic protein profiles were found for specific processes such as hot and cold break. Ultra‐high‐pressure treatments were found to generally preserve the integrity of tomato proteins and this was reflected by the unaltered IgE reactivity observed. Copyright © 2007 Society of Chemical Industry
Toxicogenomic analysis of gene expression changes in human liver cells after exposure to environmentally friendly lubricants
Authors: Erlenkaemper B. , Eisentraeger A. 
Published: January 2007

AbstractA lubricant based on synthetic esters and a mixture of this lubricant with additives and metals simulating the intake caused by usage were investigated with various ecotoxicological and genotoxicological tests. Tests with algae, daphnids and bacteria demonstrated an influence of the mixture on ecotoxicity. The genotoxicity tests, however, showed no effects for both samples. In addition, genetic effects were examined in detail by using gene expression profiles of HepG2 cells. Comparison of the set of regulated genes for early and late time points indicated a certain concordance between the genes up‐regulated after 6 and 24 hours of exposure. The correlation for the corresponding down‐regulated gene groups is slightly lower. Generally, the number of regulated genes is low (3–6%) demonstrating a marginal influence. The results indicate that the assessment of gene expression profiles, in addition to the quantification of toxic effects, may give important information on ways of toxic action of a substance. These data can be used in the development of new chemicals or products in order to minimize toxic effects. Copyright © 2007 John Wiley & Sons, Ltd.
Poly(2‐oxazoline)s: Alive and Kicking
Authors: Hoogenboom Richard 
Published: January 2007

AbstractThe development of various living/controlled polymerization techniques has allowed the synthesis of a large variety of well‐defined (co)polymers with varied polymer length, composition, and architecture, for example. Screening this large possible parameter space for a polymer with certain properties can be a very demanding process. Therefore, we aim to rapidly synthesize and systematically screen libraries of copolymers to determine structure‐property relationships that might allow the future design of novel (co)polymers with predictable properties. The cationic ring‐opening polymerization of 2‐oxazolines has been adapted for the synthesis of libraries of well‐defined (co)polymers. In this contribution, the optimization of the polymerization procedure using both high‐throughput experimentation and microwave irradiation is discussed. Subsequently, the microwave‐assisted synthesis of well‐defined libraries of (co)poly(2‐oxazoline)s and the determination of structure‐property relationships for these polymers is described. Moreover, the polymerization of a soy‐based 2‐oxazoline monomer will be illustrated as a ‘green’ approach to replace current oil‐based feedstock by renewable resources.magnified image
Superior Nanoporous Polyimides via Supercritical CO2 Drying of Jungle‐Gym‐Type Polyimide Gels
Authors: Kawagishi Ken , Saito Hiromu , Furukawa Hidemitsu , Horie Kazuyuki 
Published: January 2007

AbstractWe report novel nanoporous polyimides formed from jungle‐gym‐type rigid polyimide gels by supercritical CO2 drying. By virtue of supercritical CO2 drying to avoid the collapse of nanostructure, porosity above 90 vol.‐% was achieved. We found a rich variety of nanoporous structures in the range of 50–800 nm such as crisp fragments, minute network, and highly‐connected beads. These characteristic structures were formed by the competitive progress of liquid‐liquid phase separation and crystallization induced due to the two chemical reactions of end‐crosslinking and thermal imidization during gelation.magnified image
Swelling and Dissolution of Cellulose Part 1: Free Floating Cotton and Wood Fibres in N‐Methylmorpholine‐N‐oxide–Water Mixtures
Authors: Cuissinat Celine , Navard Patrick 
Published: January 2007

AbstractSummary: Five modes describing the behaviour of cellulose fibres dipped in a chemical have been identified:

Mode 1: Fast dissolution by disintegration into fragments

Mode 2: Large swelling by ballooning, and dissolution

Mode 3: Large swelling by ballooning, and no dissolution

Mode 4: Homogeneous swelling, and no dissolution

Mode 5: No swelling and no dissolution

In the case of the behaviour of wood and cotton cellulose fibres in N‐methylmorpholine‐N‐oxide (NMMO) and water mixtures, four domains of water content have been identified. Below 17% of water up to monohydrate (13%), the fibres are disintegrated into rod‐like fragments and dissolve (mode 1). In NMMO – water mixtures containing 19–24% water, the cellulose fibres exhibit a heterogeneous swelling by forming balloons (composed of dissolved cellulose holds inside a membrane) separated with non‐swollen sections. The whole fibre will completely dissolve (mode 2) in four successive steps (growth of the balloons, burst of the balloons, dissolution of the non‐swollen sections and finally dissolution of the membrane). With still greater water contents (25–30%), only the ballooning phenomenon is observed, with a partial dissolution inside the balloon (mode 3). Above 35% of water, the fibres swell homogeneously and are not dissolving (mode 4).
Electrokinetic Investigations of Oriented Cellulose Polymers
Authors: Reischl Martin , Stana‐Kleinschek Karin , Ribitsch Volker 
Published: January 2007

AbstractSummary: Electrokinetic investigations of different cellulosic fibres were reviewed with special emphasis on polymer composite materials and textile applications of cellulose fibres. The possibilities in the interpretation of zeta‐potential data regarding chemical and physical modification, specific adsorption, swelling and changes in hydrophobicity/hydrophilicity of cellulose polymers are discussed. Using recent data from literature, advantages and limitations of electrokinetic measurements of oriented polymers are described, finding that the zeta‐potential is a valuable parameter in polymer surface characterisation.
Effects of Different Drying Processes on the Material Properties of Bacterial Cellulose Membranes
Authors: Clasen C. , Sultanova B. , Wilhelms T. , Heisig P. , Kulicke W.‐M. 
Published: January 2007

AbstractSummary: Membranes of bacterial cellulose produced by Gluconacetobacter xylinus show a high water and gas permeability that can be altered by different drying techniques. It could be shown that freeze‐drying reduces the swellability of the polymer membranes by a factor of 5 while evaporation drying causes a reduction by a factor of 50. The strong decrease of swellability for an evaporation dried membrane could be correlated with a reduction of the absolute number of polymer strands that form the network structure of the membrane, determined with oscillatory shear rheological experiments. The removal of network meshes by a complete aggregation of polymer strands could be confirmed by IR‐spectroscopy with an increased degree of intramolecular hydrogen bonding of cellulose strands. In contrast to this, the freeze‐drying process shows a slight increase of the number of network meshes due to partial aggregation of free polymer strands. Freeze‐dried membranes show a gas permeability two orders of magnitude higher then evaporation dried membranes. The absolute permeability strongly depends on the bacterial strain used for the polymer membrane synthesis and varies by up to 1.5 orders of magnitude for the same drying process. The Young's modulus of the polymer membranes varies with the bacterial strain used, but does not show the same trends as the permeability. Finally, a comparison of the characterized properties shows that only one of the tested strains shows the capability to synthesize membranes that meets the requirements for an application as a wet wound dressing.
Studies on Non‐natural Deoxyammonium Cellulose
Authors: Heinze Thomas , Koschella Andreas , Brackhagen Meinolf , Engelhardt Jürgen , Nachtkamp Klaus 
Published: January 2007

AbstractSummary: Ammonium group containing cellulose derivatives are prepared from homogeneously synthesized cellulose p‐toluenesulfonic acid esters (tosyl cellulose) by conversion with sodium azide and subsequent reduction of the azido moiety applying NaBH4/CoBr2/2,2′‐bipyridine as reagent. Regarding the tosylation, cellulose samples of different degree of polymerization and hemicellulose content possess a different reactivity. The deoxyamino cellulose is water soluble in the protonated state. Elemental analysis, FTIR‐ and NMR spectroscopy were carried out to analyze the degree of substitution and functionalization pattern. It was also studied to synthesize deoxyazido celluloses without isolation of the tosyl cellulose. However, a predominant formation of deoxychloro moieties occurs.
Mechanical Properties of Regenerated Cellulose Fibres for Composites
Authors: Adusumali Ramesh‐Babu , Reifferscheid Moritz , Weber Hedda , Roeder Thomas , Sixta Herbert , Gindl Wolfgang 
Published: January 2007

AbstractSummary: A broad variety of regenerated cellulose fibres was subjected to single fibre tensile tests in order to determine the modulus of elasticity, tensile strength, and failure strain. The results were compared to glass fibres and flax fibres, which are considered the most important technical and natural fibres, respectively. With regard to their modulus of elasticity and tensile strength, regenerated cellulose fibres showed clearly lower values than glass fibres, even when their low density was taken into account. The average modulus of elasticity and tensile strength of regenerated cellulose fibres was also lower than the values measured for flax fibres, but when variability was considered, both fibres performed similarly. In terms of interfacial shear strength with polypropylene, lyocell fibres performed significantly less well than sized glass fibre and ramie fibre. The most important difference between regenerated cellulose fibres and both glass and flax fibres is their high failure strain and thus high work to fracture. The high work to fracture of regenerated cellulose fibres makes them particularly useful for composite applications where high fracture toughness is required.
Nanocellulose Polymer Composites as Innovative Pool for (Bio)Material Development
Authors: Kramer Friederike , Klemm Dieter , Schumann Dieter , Heßler Nadine , Wesarg Falko , Fried Wolfgang , Stadermann Dietmar 
Published: January 2007

AbstractSummary: Using a “never‐dried” procedure (according to Figure 4) shaped bacterial nanocellulose (BC, 1% cellulose, 99% water) has been modified by the formation of BC‐polymer composites. For this purpose, acrylate and methacrylate monomers and methacrylate crosslinkers were photopolymerized inside an ethanol‐swollen nanofiber network. Using the ethanol as solvent and as confirmed by model reactions the synthetic polymer (SP) part of the composites is constructed of crosslinked polymers (number of repeating units in the range of 500). As part of ongoing work on the development of (bio)materials from the innovative pool of BC composites these investigations are recently directed towards the creation of collagen‐like materials. Thus, for these purposes, mainly water absorption capacity, strength, and elasticity have to be controlled, whilst still retaining essential features of BC like shape, nanofiber network, pore system, and proved biocompatibility. Using acrylic acid, 2‐ethylhexyl acrylate, 2‐hydroxyethyl methacrylate, N‐vinyl pyrrolidone as acrylate monomers and triethylene glycol dimethacrylate and 1,4‐butandiol dimethacrylate as crosslinkers of different concentrations either a filling of the pores or a coating of the fibers in the BC nanocomposites could be achieved. The small cellulose content of the composites significantly increases the water absorption value and the strength of the material as well as the ability of re‐swelling in the case of fiber coated composites. Sample 12 is an optimized BC‐SP composite regarding important properties of hyaline cartilage like Young's modulus in the range of 5–20 MPa using the well‐known Simplex‐method.
Functionalized Cellulose Based Microcomposites
Authors: Kolbe Axel , Meister Frank 
Published: January 2007

AbstractSummary: A technique has been developed that allows the production of cellulosic micro composites by immobilizing super‐ground functionalised materials in the cellulose matrix. For this purpose, the well‐established ALCERU® process has been a subject of technological modification. Depending on the degree of filling, several types of composites are accessible. At lower concentrations, the fibres maintain their textile‐physical parameters and may be used in applications, where a textile appearance is required. The increasing concentration of the functional additives influences increasingly the overall properties of the composite and leads to composites with special functions such as water retention, electric conductivity, and specific absorption ability for organics or heat storage functions. In addition, loads exceeding the cellulose portion are useful as green shapes for ceramics.