bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative small‐animal surrogate to evaluate drug efficacy in preventing wear debris‐induced osteolysis
Authors: Schwarz Edward M. , Benz Eric B. , Lu Allen P. , Goater J. Jeffrey , Mollano Anthony V. , Rosier Randy N. , Puzas J. Edward , O'Keefe Regis J. 
Published: February 2005

AbstractIndividuals who suffer from severe joint destruction caused by the various arthritidies often undergo total joint arthroplasty. A major limitation of this treatment is the development of aseptic loosening of the prosthesis in as many as 20% of patients. The current paradigm to explain aseptic loosening proposes that wear debris generated from the prosthesis initiates a macrophage‐mediated inflammatory response by resident macrophages, leading to osteoclast activation and bone resorption at the implant interface. No therapeutic interventions have been proved to prevent or inhibit aseptic loosening. The development of therapeutic strategies is limited due to the absence of a quantitative surrogate in which drugs can be screened rapidly in large numbers of animals. We have previously described a model in which titanium particles implanted on mouse calvaria induce an inflammatory response with osteolysis similar to that observed in clinical aseptic loosening. Here, we present new methods by which the osteolysis in this model can be quantified. We determined that 6–8‐week‐old mice in normal health have a sagittal suture area of 50 (±6) μm2, which contains approximately five osteoclasts. As a result of the titanium‐induced inflammation and osteolysis, the sagittal suture area increases to 197 (±27) μm2, with approximately 30 osteoclasts, after 10 days of treatment. The sagittal suture area and the number of osteoclasts in the calvaria of sham‐treated mice remained unchanged during the 10 days. We also determined the effects of pentoxifylline, a drug that blocks the responses of tumor necrosis factor‐α to wear debris, and the osteoclast inhibitor alendronate. We found that both drugs effectively block wear debris‐induced osteolysis but not osteoclastogenesis. In conclusion, we found the measurements made with this model to be reproducible and to permit quantitative analysis of agents that are to be screened for their potential to prevent aseptic loosening.
Biomechanical regulation of matrix metalloproteinase‐9 in cultured chondrocytes
Authors: Jin Gang , Sah Robert L. , Li Yi‐Shuan , Lotz Martin , Shyy John Y‐J. , Chien Shu 
Published: February 2005

AbstractAbnormal mechanical loading of joints may induce degeneration of articular cartilage. Shear stress is one mode of mechanical loading that may regulate chondrocyte metabolism. We investigated the mechanism by which shear stress induces the gene encoding matrix metalloproteinase‐9, a mediator of the progressive degradation of articular cartilage in osteoarthritis. In vitro experiments using passaged rabbit chondrocytes in monolayer culture subjected to a shear stress of 16 dyn/cm2 (1.6 Pa) in a flow channel showed increased expression of the matrix metalloproteinase‐9 gene. The induction of matrix metalloproteinase‐9 appeared to depend on a region in the 5′ promoter of the gene that contains a 12–0‐tetradecanoylphorbol 13‐acetateresponsive element. Transfection experiments using a construct containing a luciferase reporter driven by a 12–0‐tetradecanoylphorbol 13‐acetate‐responsive element indicated that shear stress activated a 12–0‐tetradecanoylphorbol 13‐acetate‐responsive element‐mediated transcription in chondrocytes. Similar experiments showed that shear stress induced a matrix metalloproteinase‐9 promoter construct (matrix metalloproteinase‐9‐luciferase). Shear stress activated c‐Jun NH2‐terminal kinase, extracellular signal‐regulated kinase, and p38. Transfection o, matrix metalloproteinase‐9‐luciferase together with the dominant negative mutant of c‐Jun NH2‐terminal kinase, but not with that of extracellular signal‐regulated kinase or p38, attenuated the shearinduced matridx metalloproteinase‐9 promoter activity. In addition, transfection of constructs encoding dominant negative mutants of Ras, Rac, and Cdc42 attenuated the induction of c‐Jun transcriptional activity by shear stres. Thus, shear stimulation of chondrocytes stimulates Ras, Rac, and Cdc42, which subsequently activate c‐Jun NH2‐terminal kinase to induce a 12–0‐tetradecanoylphorbol 13‐acetate‐responsive elementmediated expression of matrix metalloproteinase‐9.
Delamination rates of tissue flaps used in articular cartilage repair
Authors: Driesang Iris M. K. , Hunziker Ernst B. 
Published: February 2005

AbstractA popular strategy in the treatment of articular cartilage lesions involves the introduction of cell suspensions into the defect void and its closure with a periosteal flap (autologous chondrocyte transplantation technique). We applied this methodology in goats and discovered that all sutured flaps (n = 6 animals) became detached from nonimmobilized joints during the recovery period. The purpose of this study was to ascertain whether postoperative restriction of joint movement could prevent the delamination of flaps. Partial‐thickness defects were created in the knee joint cartilage of 27 goats. These defects were then filled with a fibrin matrix and covered with periosteal (n = 6) or fascial (n = 21) flaps, which were sutured with simple, interrupted stitches to the surrounding tissue. The joints were immobilized by means of a modified Robert Jones bandage for periods of 2–6 weeks, after which time they were inspected for the absence or presence of flaps. In four animals, joint immobilization for 3 weeks was followed by free movement for a similar period. Four of the six periosteal flaps and two of the 21 fascial ones became delaminated after the period of immobilization. In the four goats permitted 3 weeks of free joint movement following a similar period of joint immobilization, all flaps (which had been retained up to the end of the immobilization period) became detached. These findings indicate that joint immobilization hinders the delamination of flaps but that this restriction of movement must be sustained for an undefined period of time. The nature of the tissue used for flaps also influences their rate of retention by immobilized joints.
Quantitative assessment of in vivo bone regeneration consolidation in distraction osteogenesis
Authors: Windhagen Henning , Kolbeck Stefan , Bail Hermann , Schmeling Arno , Raschke Michael 
Published: February 2005

AbstractWe present a new method for quantitatively assessing the consolidation of bone regeneration by performing distraction osteogenesis in micropigs. We measured in vivo stiffness using a newly developed, revolving, bone‐healing meter. After the micropigs were killed, we obtained maximum torsional moment data for the regenerated bones by destructive mechanical testing, and we then correlated these data with the data for stiffness. We found a highly significant regression between in vivo stiffness and maximum torsional moment (r2 = 0.80), suggesting that monitoring stiffness may be useful for the prediction of bone regeneration in distraction osteogenesis. Therefore, our method may be a reliable tool for future quantitative monitoring of healing progress in patients with healing bones or in animal studies addressing treatments to increase bone formation in long‐bone defects.
Osteoprogenitor cells within skeletal muscle
Authors: Bosch Patrick , Musgrave Douglas S. , Lee Joon Yung , Cummins Jim , Shuler Franklin , Ghivizzani Steven C. , Evans Chris , Robbins Paul D. , Huard Johnny 
Published: February 2005

AbstractThe formation of ectopic bone within skeletal muscle is a widely observed phenomenon. However, the source of the osteoprogenitor cells responsible for ectopic bone formation remains unknown. This study was designed to test for osteogenic differentiation among cells isolated from skeletal muscle tissue. Different subpopulations of cells derived from an adult mouse skeletal muscle were tested for induction of alkaline phosphatase activity after exposure to bone morphogenetic protein‐2 in vitro. A responsive subpopulation was identified, transduced with a retrovirus encoding for β‐galactosidase (Rv‐lacZ) and an adenoviral construct encoding for one bone morphogenetic protein‐2, and injected into the hindlimb of immune compromised (severe combined immunodeficient, or SCID) mice. The injected cells appeared to actively participate in the ectopic bone formation. The existence of lacZ‐positive muscle‐derived cells colocalized with osteocalcin‐producing cells within lacunae of newly formed bone matrix suggests osteoblast and osteocyte differentiation. Although a specific cell was not isolated, these data support the contentions that osteoprogenitor cells reside within skeletal muscle and that muscle may represent a source other than bone marrow for the harvest of these cells.
The influence of frying medium degradation on fat uptake and texture of French fries
Authors: Kita Agnieszka , Lisińska Grażyna , Powolny Małgorzata 
Published: February 2005

AbstractThe purpose of the present investigation was to study the influence of the degree of degradation of different kinds of oils used as a frying medium on fat uptake and texture of frozen pre‐fried French fries. As has been found, the degradation degree of the frying medium depends on the kind of oil and processing time. Liquid hydrogenated rapeseed oil exhibited the best thermo‐oxidative stability among the oils under investigation. The kind of oil influenced fat uptake and the texture of French fries. The lowest fat uptake was observed with French fries fried in solid oil. Some correlations between fat uptake and changes in fatty acid content were found in the frying medium during frying. Fat absorption increased with increasing unsaturated fatty acids and decreasing saturated fatty acid content. The texture of French fries fried in hydrogenated oils was harder than that exhibited by French fries fried in liquid rapeseed oil. The hardness of French fries fried in liquid oils decreased during frying while the hardness of French fries fried in solid oil increased. Some correlations between the texture of French fries and iodine value and fatty acids content of frying media were found. The hardness of French fries increased with increasing content of saturated fatty acids and decreasing unsaturated fatty acids and trans isomer fatty acid content. Copyright © 2005 Society of Chemical Industry
Rheological and Structural Investigation of Layered Silicate Nanocomposites Based on Polyamide or Polyethylene: Influence of Processing Conditions and Volume Fraction Effects
Authors: Médéric Pascal , Razafinimaro Tolotrahasina , Aubry Thierry , Moan Michel , Klopffer Marie‐Hélène 
Published: February 2005

AbstractOrganoclay polymer nanocomposites offer improved material properties at very low filler loadings making them of immediate interest for industrial applications. In this study two matrices are used : a polar polymer, PA12, and a non polar polymer, LLDPE. Many articles focused on the importance of the chemistry used to modify the surface of the clay. Numerous papers studied the influence of the compatibilizing agent necessary to obtain intercalated structure, when the matrix is non polar. This paper demonstrates the importance of the way the clay was melt processed into the thermoplastic matrix. Layered silicate nanocomposites based on PA12 or LLDPE were characterized by X‐ray diffraction, transmission electron microscopy and rheological tests. The influence of volume fraction on rheological and structural properties is also investigated.
Starch Nanocrystal Fillers in an Acrylic Polymer Matrix
Authors: Angellier Hélène , Putaux Jean‐Luc , Molina‐Boisseau Sonia , Dupeyre Danielle , Dufresne Alain 
Published: February 2005

AbstractAqueous suspensions of nanocrystals can be obtained by acid hydrolysis of native waxy maize starch granules. The disruption of waxy maize starch granules by 2.2N HCl hydrolysis has been followed by scanning and transmission electron microscopy and laser granulometry. The mechanical properties of composite materials made of poly(styrene‐co‐butyl acrylate) filled with starch nanocrystals were characterized by dynamic mechanical analysis. These nanocrystals appeared to be an interesting reinforcing phase in a thermoplastic matrix.
Polymer Layered Silicate/Carbon Nanotube Nanocomposites: Morphological and Rheological Properties
Authors: Peeterbroeck S. , Alexandre M. , Nagy J.B. , Moreau N. , Destrée A. , Monteverde F. , Rulmont A. , Jérôme R. , Dubois Ph. 
Published: February 2005

AbstractMorphological and rheological properties of new ternary nanocomposites based on ethylene vinyl acetate copolymers (EVA), commercial organo‐modified clays (organoclays) and purified multi‐walled carbon nanotubes (MWNTs), prepared via direct melt blending, have been evaluated. For sake of comparison, the corresponding binary compositions, i.e., EVA filled with either organoclays or MWNTs, have been investigated as well. While extensive exfoliation can be observed for binary EVA/clay nanocomposites, the addition of MWNTs appears to limit clay exfoliation. Rheological properties show that both clay and MWNTs increase the elastic modulus of the nanocomposites, reflecting the high degree of nanoparticle interconnectivity that can be found in these materials.
Synthetic Hydromagnesite as Flame Retardant. A Study of the Stearic Coating Process
Authors: Haurie Laia , Fernández Ana Inés , Velasco José Ignacio , Chimenos Josep Maria , Ticó‐Grau Josep Ramón , Espiell Ferran 
Published: February 2005

AbstractA synthetic hydromagnesite obtained from an industrial by‐product rich in magnesium oxide was employed and evaluated as a non‐halogenated flame retardant for poly(ethylene‐co‐vinyl acetate).The filler was characterized with different techniques (such as specific surface area, TGA, particle morphology and size measurements, WAXS). Significant differences were found between the synthetic hydromagnesite and the natural one.Synthetic hydromagnesite was coated with stearic acid and the effectiveness of the coating process was studied by the dye adsorption method and sedimentation volume measurements. The amount of coating agent ranged from 1 to 4.5%. This factor was found to have a significant effect on the thermal decomposition behaviour of the filler.A poly(ethylene‐co‐vinyl acetate) (27% of VA) was filled with the coated synthetic grades of hydromagnesite as well as with two commercial flame retardants and different physicochemical properties were evaluated, including their flame retardant effect.
Treatment of SMC Composite Waste for Recycling as Reinforcing Fillers in Thermoplastics
Authors: Perrin Didier , Leroy Eric , Clerc Laurent , Bergeret Anne , Lopez‐Cuesta José‐Marie 
Published: February 2005

AbstractNeeds for recycling thermoset composite materials are considerably increasing. Unfortunately, such materials are particularly difficult to recycle due to their crosslinked nature. In this paper, we focus on the case of Sheet Moulding Compounds (SMC), which consist of an unsaturated polyester filled with glass fibres and calcium carbonate. We consider the possibilities of mechanical treatments allowing to obtain ground fractions that could be used as fillers for the reinforcement of thermoplastics. Two processes are described and compared with an existing industrial one. Finally, optimised fractions of SMC waste are introduced into polypropylene, leading to promising results in term of mechanical properties.
Modified Cellulose Fibers as Reinforcing Fillers for Macromolecular Matrices
Authors: Gandini Alessandro , Belgacem Mohamed Naceur 
Published: February 2005

AbstractVarious cellulose substrates were submitted to different surface OH chemical modifications in non‐swelling media and then fully characterised by FTIR, XPS, contact angle measurements and elemental analysis. The alternative procedures adopted were:(i) simple grafting with monomeric or oligomeric agents which bore one or several reactive functions, either as a single terminal moiety or as numerous moieties placed along the chain;(ii) grafting with polymerisable molecules, which involved the use of reagents of small molecular size, but bearing two functions, one able of reacting with the surface cellulose OH groups and the other used as a source of subsequent covalent linkage with the matrix;(iii) the use of planar stiff molecular configurations bearing two identical reactive functions, calling upon the working hypothesis that only one function will react with a cellulose OH group, whereas the other will be left to copolymerise with the matrix;(iv) coupling with siloxanes using the same strategy as in (ii), except for the fact that this specific approach involves molecules already commonly used in glass fibres treatment;(v) grafting with organometallics such as triethyl aluminium following the same working hypothesis as in (iii) but with a second reaction involving monomeric or polymeric alcohols or amines.
RNA in the nucleus of a motile plant spermatozoid: Characterization by enzyme‐gold cytochemistry and in situ hybridization
Authors: Rejon Emmanuelle , Bajon Catherine , Blaize Annie , Robert Daniel 
Published: February 2005

AbstractTo investigate the decrease of transcription and to determine the localization of RNA molecules during spermiogenesis in the fern Scolopendrium, we have used the enzyme‐gold electron microscope method. During cell differentiation, the labeling decreases over the cytoplasm and increases over the nucleus. In the latter, the nucleolus disappears at the beginning of differentiation and the gold particles that were at first situated over the dispersed chromatin are then located over the condensed chromatin. In mature gametes, gold particles linked to RNA are abundant over the dense and homogeneous nucleus and sparse over the cytoplasm. By using in situ hybridization of RNA‐poly(A) tails with radioactive poly(U) probes, we have shown that these RNA molecules are mRNA; they are located in the condensed chromatin of the mature sperm nucleus.
Chromatin arrangement in mouse sperm nuclei: An ultrastructural cytochemical study
Authors: Biggiogera M. 
Published: February 2005

AbstractThe arrangement of mouse sperm nuclei chromatin and, in particular, of DNA has been studied by electron microscopic cytochemistry. It had been previously shown that, after a Feulgen‐type reaction using an osmium ammine complex (OAC), the OAC‐stained DNA was distributed in a spotted pattern in the nucleus (Biggiogera: Basic Appl Histochem 30:501–504, 1986). The present chapter shows that this pattern is characteristic of mouse spermatozoa from testis to vas deferens, with the exception of some testicular spermatozoa, in which DNA was homogeneously stained. DNase digestion of thin‐sectioned nuclei resulted in a distribution of residual material complementary to the pattern of the unstained zones after the OAC reaction. These findings are discussed considering the role of –S–S– crosslinks, characteristics of this extremely condensed chromatin, in limiting the availability of DNA to acid hydrolysis.
Mouse zygotes injected with mitochondria develop normally but the exogenous mitochondria are not detectable in the progeny
Authors: Ebert Karl M. , Alcivar Acacia , Liem Hetty , Goggins Rick , Hecht Norman B. 
Published: February 2005

AbstractA microinjection procedure to introduce “paternal” mitochondria from a source other than spermatozoa into fertilized mouse eggs is described. When a mitochondrial suspension isolated from the testes or liver of Mus molossinus mice was microinjected into fertilized eggs of CD1 mice, the microinjected zygotes survived, developed normally, and offspring were produced. Mus molossinus mitochondrial DNA can be distinguished from CD1 mitochondrial DNA by Southern blot analyses using restriction enzymes such as Eco R1, Xba 1, or Spe 1. Although up to 120 viable mitochondria were injected, no exogenous mitochondrial DNA was detected in fetal samples or in the brain, liver, heart, testis, or ovary of the mature progeny. Under the experimental conditions used, similar results were obtained when mitochondria from the testes of New Zealand black mice or from testes of Syrian hamsters were microinjected into fertilized CD1 mouse eggs. Failure to detect the exogenous mitochondrial DNA under our assay conditions suggests that microinjected mitochondria from testis or liver did not selectively replicate during embryonic development. The “foreign” mitochondria appear to have the same fate during early embryogenesis as the mitochondria of the spermatozoon.
Selection of mouse preimplantation embryos carrying exogenous DNA by polymerase chain reaction
Authors: Ninomiya Takashi , Hoshi Masaki , Mizuno Atsuko , Nagao Masaya , Yuki Atsushi 
Published: February 2005

AbstractA polymerase chain reaction (PCR) system to detect transgenes in mouse preimplantation embryos was employed so that transgenic embryos could be selected before they were transferred to recipient mice. The selection system involves bisection of morulae, selection of the half‐morulae containing target sequences within 7 hr, and culture and transfer of the sister half‐morulae. PCR analysis of morulae derived from transgenic mice confirmed that the PCR system was reliable. However, five of 41 implanted embryos derived from PCR‐positive morulae did not contain the transgenes. Also, one of 28 implanted embryos from PCR‐negative morulae were transgenic. The selection system was applied to fertilized mouse eggs into which pSV2‐gpt‐gE1A DNA was injected. The injected DNA was detected in 30 of 84 morulae derived from the microinjected eggs. All seven implanted embryos developed from PCR‐negative morulae had no detectable amount of transgenes, and one of two successfully implanted embryos from PCR‐positive morulae was transgenic.
Qualitative changes in protein synthesis associated with polyspermic fertilization of human eggs
Authors: Dionne P. , Duchesne C. , Sullivan R. 
Published: February 2005

AbstractTo investigate the early molecular events in human oocytes that are triggered by fertilization, the authors examined the pattern of polypeptides synthesized by unfertilized and dispermic embryos obtained through an in vitro fertilization and embryo transfer (IVF‐ET) program. Compared with unfertilized oocytes of the same postovulatory age, the de novo protein synthesis in tripronuclear dispermic zygotes (21 hours postinsemination) was characterized by the appearance of three novel protein bands with molecular weights of 41.2, 35.3, and 26.0 kD. Concomitant with these changes, these zygotes showed the disappearance of bands at 54.0, 36.5, and 28.0 kD, along with the decreased synthesis of a protein band at 42.5 kD. Although 24% of the aged unfertilized oocytes exhibited bands corresponding to 41.2 and 35.3 kD, the 26.0 kD protein is restricted to the tripronuclear embryos. The significance of these results is discussed in relation to the use of polyspermic human oocytes as a model for the study of the early molecular events triggered by fertilization.
Spatial patterns of gene expression in preimplantation mouse embryos
Authors: Nisson Paul E. , Francis Susan , Crain William R. 
Published: February 2005

AbstractThe distribution of total polyadenylated RNA and mRNAs from the β‐actin, fibronectin, and cytokeratin Endo A genes was examined in preimplantation mouse embryos using in situ hybridization of riboprobes to RNA in sections of embryos. Polyadenylated RNA was found in the cytoplasm of all cells of blastocyst‐stage embryos, whereas the specific mRNAs displayed three distinct patterns of expression: uniform throughout the embryo (β‐actin), enriched in the inner cell mass (fibronectin), and enriched in the trophectoderm (Endo A). In eight‐cell embryos, the polyadenylated RNA was more concentrated in nuclei than in the cytoplasm (as noted previously), although this was not the case in blastocysts, nor was it true for the specific mRNAs that were examined. These experiments demonstrate that there is localized gene expression in the early mouse embryo, which correlates with the formation of the trophectoderm and the inner cell mass.