bluuebunny/crossref_metadata_2025 huggingface dataset:
Styrene and butyl methacrylate copolymers and their application in leather finishing
Authors: Mohamed O. A. , Moustafa A. B. , Mehawed M. A. , El‐Sayed N. H.
Published: October 2008

Homopolymers and copolymers of styrene and butyl methacrylate were synthesized with different ratios by an emulsion polymerization technique with K2S2O8/NaHSO3 as the redox initiation system and sodium dodecyl sulfate as the emulsifier at 60°C for 3 h. The effects of different monomer ratios on the kinetics of emulsion polymerization and polymer viscosity were studied. These copolymers were applied to leather surfaces with a hand coater to a thickness of 18 μm. The effects of the coatings on the leather surfaces were evaluated through the measurement of physical and mechanical properties of coated and uncoated leather. IR spectra showed new bands characteristic of styrene and butyl methacrylate, which disappeared in the spectrum of uncoated leather. The physical and mechanical results showed that the water absorption content decreased with increasing styrene content, and the water vapor permeability of the coated leather was less than that of the uncoated leather; however, it was still in the acceptable range. The results indicated improvements in the tensile strength and elongation (%) for the coated leather with increases in the butyl methacrylate content. Thermogravimetric analysis showed characteristic improvements in the thermal stability of leather after the coating; its optimum stability was reached when the leather was coated with poly(styrene:butyl methacrylate) (1 : 1). Finally, scanning electron microscopy showed the full grain surface of the leather. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Fabrication and properties of core‐shell structure P(LLA‐CL) nanofibers by coaxial electrospinning
Authors: Xiaoqiang Li , Yan Su , Rui Chen , Chuanglong He , Hongsheng Wang , Xiumei Mo
Published: October 2008

In this article, core‐shell structure nanofibers were fabricated by coaxial electrospinning with biodegradable copolymer Poly(L‐Lactic‐ε‐Caprolactone) [P(LLA‐CL) 50 : 50] as shell and bovine serum albumin (BSA) as core. Morphology and microstructure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The mechanical properties were investigated by stress‐strain tests. In vitro degradation rates of the nanofibrous membranes were determined by measuring their weight loss when immersed in phosphate‐buffered saline (pH 7.4) for a maximum of 14 days. Release behavior of BSA was measured by an ultraviolet‐visible spectroscopy, and the results demonstrated that BSA could release from P(LLA‐CL) nanofibers in a steady manner. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Biodegradation of oxo‐biodegradable polyethylene
Authors: Reddy M. M. , Deighton M. , Gupta Rahul K. , Bhattacharya S. N. , Parthasarathy R.
Published: October 2008

Biodegradation of polyethylene and oxo‐biodegradable polyethylene films was studied in this work. Abiotic oxidation, which is the first stage of oxo‐biodegradation, was carried out for a period corresponding to 4 years of thermo‐oxidation at composting temperatures. The oxidation was followed by biodegradation, which was achieved by inoculating the microorganism Pseudomonas aeruginosa on polyethylene film in mineral medium and monitoring its degradation. The changes in the molecular weight of polyethylene and the concentration of oxidation products were monitored by size exclusion chromatography and Fourier transform infrared (FTIR) spectroscopy, respectively. It has been found that the initial abiotic oxidation helps to reduce the molecular weight of oxo‐biodegradable polyethylene and form easily biodegradable product fractions. In the microbial degradation stage, P. aeruginosa is found to form biofilm on polymer film indicating its growth. Molecular weight distribution data for biodegraded oxo‐biodegradable polyethylene have shown that P. aeruginosa is able to utilize the low‐molecular weight fractions produced during oxidation. However, it is not able to perturb the whole of the polymer volume as indicated by the narrowing of the polymer molecular weight distribution curve toward higher molecular fractions. The decrease in the carbonyl index, which indicates the concentration of carbonyl compounds, with time also indicates the progress of biodegradation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
New manganese catalyzed regiocontrolled synthesis of poly(2,5‐dialkyl‐1,4‐phenylene oxide)s
Authors: Lin Kun‐Yu , Su Chia‐Teh , Wang Ling‐Jiun , Huang Cheng‐Liang , Liang Mong
Published: October 2008

A new catalyst system is developed for regiocontrolled synthesis of poly(2,5‐dialkyl‐1,4‐phenylene oxide)s by oxidative coupling polymerization of 2,5‐dialkylphenol. The treatment of the α‐benzoin oxime with manganese chloride in methanol under basic condition led to the formation of manganese benziloxime complex in which α‐benzoin oxime was converted to benziloxime and coordinated to manganese as bidentate ligands. The polymerizations were conducted in toluene using manganese benziloxime complex and dibutylamine in a continuous flow of oxygen, and the structures, properties of the catalyst, and polymers were studied by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). The catalyst showed high regioselectivity and reasonably good yields to afford the poly(2,5‐dimethyl‐1,4‐phenylene oxide)s with 1,4‐C‐O linkage structure which possessed melting point higher than the poly(p‐phenylene sulfide) or type II liquid crystalline polymer. The regioselectivity was enhanced when employing molecular sieves‐supported manganese catalyst system at 90°C and the crystallinity of poly(2,5‐dimethyl‐1,4‐phenylene oxide)s was estimated by wide‐angle X‐ray scattering (WAXS) and DSC. The crystallinity was calculated about 23.7% and a heat‐reversible melting and crystallization behavior occurred at 327.8 and 306.8°C, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of die design on die drool phenomenon for metallocene based LLDPE: Theoretical and experimental investigation
Authors: Chaloupková Kateřina , Zatloukal Martin
Published: October 2008

The effect of die design on the die drool phenomenon was investigated for metallocene based LLDPE. It has been found that die exit opening and the flared die design can significantly reduce the die drool phenomenon. Moreover, theoretical research has revealed that die drool onset can be explained by the negative/nonmonotonic pressure profile generated inside the die and/or at the die exit region. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and modification of aromatic polyesters with chloroacetyl 3,5‐dibromo‐p‐hydroxybenzoic acid
Authors: Ozden Sedat , Charayev A. M. , Bazheva R. C.
Published: October 2008

Aromatic copolyesters based on diphenylolpropane and 3,5‐dibromo‐p‐hydroxybenzoic acid (p‐HBA) were synthesized by an acceptor‐catalyzed polycondensation method. During the synthesis, equimolar mixtures of chloranhydrides of isophthalic and terephthalic acids were used. The effects of p‐HBA on the tensile and thermal properties of the polyesters were investigated. The breaking stress and modulus of elasticity increased with the amount of p‐HBA up to 10% in molar mass. A further increase in p‐HBA caused deterioration of the tensile properties. The elongation at break decreased at low p‐HBA contents (<5%). The addition of p‐HBA increased the molecular packing and the limiting oxygen index and improved the thermal behavior of the synthesized polyesters. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Electrodeposition of poly(4‐methyl carbazole‐3‐carboxylic acid) on steel surfaces and corrosion protection of steel
Authors: Düdükcü Meltem , Udum Yasemin Arslan , Ergün Yavuz , Köleli Fatih
Published: October 2008

The electropolymerization of 4‐methyl carbazole‐3‐carboxylic acid was successfully performed on a stainless steel (316L) surface with lithium perchlorate/acetonitrile as the supporting electrolyte. The corrosion resistance of the new coating, poly(4‐methyl carbazole‐3‐carboxylic acid) (PCz), was investigated. To this end, potentiodynamic polarization curves, open circuit potentials, and electrochemical impedance spectroscopy were used to evaluate the capacity of the PCz coating to protect the steel surface. The corrosion tests indicated that PCz exhibited effective anodic protection in a corrosive test solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Using of leather fibers as an additive in elastomeric compounds: Its effect on curing behavior and physico‐mechanical properties
Authors: Shabani I. , Arani Azam Jalali , Dakhel H. Ramezani , Iranmehr Gh.
Published: October 2008

In this study, leather fibers have been used as an additive in several elastomeric compounds based on nitryl butadiene rubber (NBR), chloroprene rubber (CR), ethylene–propylene–diene monomer (EPDM), and chlorinated isobutylene‐isoprene rubber (CIIR). The effects of employing fibers upon vulcanization characteristics, physico‐mechanical and thermal properties of the compounds were studied. Measuring of vulcanization characteristics of the compounds exhibited that leather fibers has no considerable effect on initial viscosity, processability, and curing time of the compounds but increases cross‐link density. Evaluation of mechanical properties of the vulcanized compounds showed that using leather fibers leads to increase in tensile strength of NBR‐based compound due to compatibility between NBR and leather fibers. Also hardness of all compounds increased drastically by employing leather fibers. The obtained results showed incorporation of leather fibers had no considerable effect on resilience, density, and thermal stability of compounds but enhanced liquid resistance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A new polymerization method and kinetics for acrylamide: Aqueous two‐phase polymerization
Authors: Guorong Shan , Zhihai Cao
Published: October 2008

The concept of aqueous two‐phase polymerization and a new polymerization method for the preparation of water‐soluble polymers are presented. The phase diagram of poly(acrylamide) (PAAm)‐poly (ethylene glycol) (PEG)‐water two‐phase system was measured by the gel permeation chromatography (GPC). The aqueous two‐phase of PAAm‐PEG‐water system can be easily formed. The critical concentration of phase separation was affected by the molecular weight of PEG. The aqueous two‐phase polymerization of acrylamide (AAm) has been successfully carried out in the presence of PEG by using ammonium persulfate (APS) as the initiator. The polymerization behaviors with varying concentration of AAm, initiator and PEG, the polymerization temperature, the molecular weight of PEG, and emulsifier types were investigated. The activation energy of aqueous two‐phase polymerization of AAm was 132.3 kJ/mol. The relationship of initial polymerization rate (Rp0) with APS and AAm concentrations was Rp0 ∝ [APS]0.72 [AAm]1.28. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crystallization behavior and mechanical properties of crosslinked plasticized poly(L‐lactic acid)
Authors: Jia Zhiyuan , Zhang Kunyu , Tan Juanjuan , Han Changyu , Dong Lisong , Yang Yuming
Published: October 2008

Enhancing the stability of plasticized poly(L‐lactic acid) (PLLA) with poly (ethylene glycol) (PEG) is necessary for its practical application. In this study, plasticized PLLA (PLLA/PEG 80/20 wt/wt) was crosslinked under γ‐ray (Co60) in the presence of triallyl isocyanurate (TAIC) as crosslinking agent. FTIR analysis revealed that PLLA, PEG, and TAIC formed a cocrosslinking structure. Crystallization behavior and mechanical properties of the crosslinked plasticized PLLA were investigated by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), and tensile tests. Experimental results indicated that the crystallization behaviors of both PEG and PLLA in the blends were restrained after irradiation. The melting peak of PEG in the crystallized samples disappeared at a low irradiation doses about 10 kGy. Although PLLA still owned the behavior of crystallize, its cold crystallization temperature and glass transition temperature shifted to higher temperature. Mechanical properties of the plasticized PLLA were strengthened through crosslinking. Both yield strength and elastic modulus of the samples increased after crosslinking. Elongation at break of the crosslinked plasticized PLLA decreased with the increase of crosslinking density but remained a high value over 200%. SEM images of fracture surfaces confirmed that the ductile fracture behavior of plasticized PLLA was kept after suitable crosslinking. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and thermal characterization of poly(ethylene oxide)/griseofulvin solid dispersions for biomedical applications
Authors: Stachurek Iwona , Pielichowski Krzysztof
Published: October 2008

In this work, a series of poly(ethylene oxide)/griseofulvin (PEO/gris) solid dispersions has been prepared and characterized by PLM, FTIR, DSC, and MT‐DSC. It has been found that the crystalline phase morphology depends strongly on the PEO molecular weight and, in the PEO/gris systems, griseofulvin molecules stay in amorphous phase of PEO, which enhances the solubility of a drug and increases its biological access. For PEO‐drug systems containing 5, 10, and 15% gris, FTIR bands due to stretching vibrations of the OH groups were found at 3436, 3436, and 3413 cm−1, respectively, whereby for pure PEO 3400, they were located at 3513 cm−1—the observed shift proves the existence of hydrogen bonds between PEO and griseofulvin. The presence of griseofulvin caused lowering of the systems' melting temperature in the whole concentration range and, as evidenced by MT‐DSC results, recrystallization of PEO in the PEO/griseofulvin systems during melting does occur. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal and crystallinity property studies of poly (L‐lactic acid) blended with oligomers of 3‐hydroxybutyrate or dendrimers of hydroxyalkanoic acids
Authors: Ni Chengyang , Luo Rongcong , Xu Kaitian , Chen Guo‐Qiang
Published: October 2008

Poly (L‐lactic acid) (PLA) is a biodegradable polymer with slow crystallization rate. Oligomers of 3‐hydroxybutyrate (OHB) and dendrimers of hydroxyalkanoic acids with different molecular weights were blended with PLA in a hope to improve the crystallization ability and thermal stability of PLA, respectively. Four thermally‐degraded PHB products oligomers termed OHB‐1, OHB‐2, OHB‐3, and OHB‐4 with various number average molecular weights (Mn) of 4000, 7400, 14,000, and 83,000, respectively, were blended with PLA. The lower cold‐crystallization temperature (Tcc) and higher heat of cold crystallization (ΔHcc) for blend of PLA/OHB‐1 suggested that thermally‐degraded OHB‐1 formed suitable crystal size during the cooling process and then acted as nucleation agents for PLA in the subsequent heating process. On the other hand, for the blending systems of PLA/dendrimers of hydroxyalkanoic acids, no obvious change on the thermal properties was observed compared with pure PLA except an improved PLA thermal stability possibly resulted from the crosslinking effects of the dendrimers © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dielectric properties of exfoliated graphite reinforced flouroelastomer composites
Authors: Xu Deng , Sridhar V. , Mahapatra S. P. , Kim Jin Kuk
Published: October 2008

Dielectric relaxation behavior of nano graphite reinforced flouroelastomer composites has been studied as a function of variation in filler in the frequency range of 0.01–105Hz. The effect of variation in filler loadings on the complex and real parts of impedance was distinctly visible which has been explained on the basis of interfacial polarization of fillers in a heterogeneous medium and relaxation dynamics of polymer chains in the vicinity of fillers. The electric modulus formalism has been utilized to further investigate the conductivity and relaxation phenomenon. The frequency dependence of AC conductivity has been investigated by using Percolation theory. The phenomenon of percolation in the composites has been discussed based on the measured changes in electric conductivity and morphology of composites at different concentrations of the filler. The percolation threshold as studied by DC conductivity occurred in the vicinity of 2.5–3.5 phr of filler loading. Scanning electron microscope microphotographs showed agglomeration of the filler above this concentration and formation of a continuous network structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Photocrosslinkable phosphorus containing homo‐ and copolyesters: Synthesis, characterization, and photosensitive properties
Authors: Kaniappan K. , Murugavel S. C.
Published: October 2008

A new series of homo‐ and copolyphosphoramide esters containing pendant chlorine group was synthesized from dihydroxy chalcones, N‐(4‐chlorophenyl)phosphoramidic dichloride, and terephthaloyl chloride by interfacial polycondensation technique. The diol monomers were prepared by condensing 4‐hydroxy benzaldehyde and 3‐methoxy‐4‐hydroxybenzaldehyde with 4‐hydroxy acetophenone. The synthesized monomers and polymers were characterized by UV, IR and 1H, 13C, and 31PNMR spectroscopic techniques. Molecular weight of the polymers was determined by gel permeation chromatography. The thermal properties of the polymers were studied by thermogravimetric analysis and differential scanning calorimetry under nitrogen atmosphere. The photo‐crosslinking ability of the polymers in various solvents was observed with UV spectrophotometer. The photocrosslinking proceeds via 2π +2π cycloaddition reaction of α, β‐unsaturated carbonyl group. The comparison study on the rate of photocrosslinking of homo and copolymers was also carried out. The chemical and physical properties of these polyesters are compared with those of the unsubstituted polyesters and the results are discussed herein. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of the effect of PEG length in Uni‐HEUR thickener behavior
Authors: Barmar Mohammad
Published: October 2008

Four new models of Uni‐HEUR associative thickener were designed and synthesized using various molecular weights of poly(ethylene glycol) (PEG) as hydrophilic segments. The PEG chain ends were capped with octadecyl isocyanate as hydrophobic segments. The structure of the prepared Uni‐HEUR thickeners was confirmed by infrared spectroscopy. The steady shear viscosity measurements of aqueous solution of HEUR models showed that the relative size of hydrophilic segments to hydrophobic segments is very important. Oscillatory measurements confirmed the steady shear viscosity results. It is found, there is an optimum relative size of hydrophilic segments to hydrophobic segments to achieve the thickener with a good performance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Glucocorticoid‐induced bone loss in mice can be reversed by the actions of parathyroid hormone and risedronate on different pathways for bone formation and mineralization
Authors: Yao Wei , Cheng Zhiqiang , Pham Aaron , Busse Cheryl , Zimmermann Elizabeth A. , Ritchie Robert O. , Lane Nancy E.
Published: October 2008

Objective

Glucocorticoid excess decreases bone mineralization and microarchitecture and leads to reduced bone strength. Both anabolic (parathyroid hormone [PTH]) and antiresorptive agents are used to prevent and treat glucocorticoid‐induced bone loss, yet these bone‐active agents alter bone turnover by very different mechanisms. This study was undertaken to determine how PTH and risedronate alter bone quality following glucocorticoid excess.

Methods

Five‐month‐old male Swiss‐Webster mice were treated with the glucocorticoid prednisolone (5 mg/kg in a 60‐day slow‐release pellet) or placebo. From day 28 to day 56, 2 groups of glucocorticoid‐treated animals received either PTH (5 μg/kg) or risedronate (5 μg/kg) 5 times per week. Bone quality and quantity were measured using x‐ray tomography for the degree of bone mineralization, microfocal computed tomography for bone microarchitecture, compression testing for trabecular bone strength, and biochemistry and histomorphometry for bone turnover. In addition, real‐time polymerase chain reaction (PCR) and immunohistochemistry were performed to monitor the expression of several key genes regulating Wnt signaling (bone formation) and mineralization.

Results

Compared with placebo, glucocorticoid treatment decreased trabecular bone volume (bone volume/total volume [BV/TV]) and serum osteocalcin, but increased serum CTX and osteoclast surface, with a peak at day 28. Glucocorticoids plus PTH increased BV/TV, and glucocorticoids plus risedronate restored BV/TV to placebo levels after 28 days. The average degree of bone mineralization was decreased after glucocorticoid treatment (−27%), but was restored to placebo levels after treatment with glucocorticoids plus risedronate or glucocorticoids plus PTH. On day 56, RT‐PCR revealed that expression of genes that inhibit bone mineralization (Dmp1 and Phex) was increased by continuous exposure to glucocorticoids and glucocorticoids plus PTH and decreased by glucocorticoids plus risedronate, compared with placebo. Wnt signaling antagonists Dkk‐1, Sost, and Wif1 were up‐regulated by glucocorticoid treatment but down‐regulated after glucocorticoid plus PTH treatment. Immunohistochemistry of bone sections showed that glucocorticoids increased N‐terminal Dmp‐1 staining while PTH treatment increased both N‐ and C‐terminal Dmp‐1 staining around osteocytes.

Conclusion

Our findings indicate that both PTH and risedronate improve bone mass, degree of bone mineralization, and bone strength in glucocorticoid‐treated mice, and that PTH increases bone formation while risedronate reverses the deterioration of bone mineralization.
Noninvasive imaging of macrophages in rheumatoid synovitis using 11C‐(R)‐PK11195 and positron emission tomography
Authors: van der Laken Conny J. , Elzinga Ernst H. , Kropholler Mark A. , Molthoff Carla F. M. , van der Heijden Joost W. , Maruyama Kaoru , Boellaard Ronald , Dijkmans Ben A. C. , Lammertsma Adriaan A. , Voskuyl Alexandre E.
Published: October 2008

Objective

Noninvasive imaging by positron emission tomography (PET) of macrophages in inflamed joints of patients with rheumatoid arthritis (RA) may allow early detection of disease activity. We undertook this study to investigate whether rheumatoid synovitis can be visualized by PET using the tracer 11C‐(R)‐PK11195, which binds to peripheral benzodiazepine receptors (PBRs) on macrophages.

Methods

Knee joints of 11 RA patients with active arthritis of at least 1 knee joint were imaged with 11C‐(R)‐PK11195 PET. Tissue uptake of 11C‐(R)‐PK11195 was quantified. PET was followed by arthroscopy of the most inflamed knee joint of each RA patient. Synovial tissue samples were subjected to immunohistochemical staining.

Results

11C‐(R)‐PK11195 uptake on the PET scans was significantly higher in severely inflamed joints than in joints with moderate or mild signs of inflammation. In addition, tracer uptake in contralateral uninflamed knee joints of RA patients was significantly higher than in uninflamed joints of control patients without inflammatory joint disease, suggesting the presence of subclinical disease activity. PET tracer uptake in joints correlated significantly with PBR staining in the sublining of synovial tissue. PBR staining correlated significantly with CD68 staining of macrophages.

Conclusion

11C‐(R)‐PK11195 PET imaging allows noninvasive in vivo imaging of macrophages in rheumatoid synovitis and possibly even in subclinical synovitis. Noninvasive visualization of macrophages may be useful both for detecting early synovitis and for monitoring synovitis activity during treatment.
The molecular signature of oxidative metabolism and the mode of macrophage activation determine the shift from acute to chronic disease in experimental arthritis: Critical role of interleukin‐12p40
Authors: Takahashi Nozomi , de Jager Victor C. L. , Glück Anton , Letzkus Martin , Hartmann Nicole , Staedtler Frank , Ribeiro‐Dias Fatima , Heuvelmans‐Jacobs Marleen , van den Berg Wim B. , Joosten Leo A. B.
Published: October 2008

Objective

Repeated injection of streptococcal cell wall (SCW) fragments results in chronic arthritis in mice. The objective of this study was to identify genes and pathways that determine disease progression based on gene expression profiling in this model.

Methods

Chronic arthritis was induced in mice by 4 injections of SCW fragments. RNA samples were isolated from synovial tissue obtained at various time points and were analyzed using mouse genome array and quantitative reverse transcription–polymerase chain reaction techniques. The functional role of potential key genes was evaluated in mice with specific gene deletions.

Results

Gene expression analyses revealed a shift in molecular signature. In contrast to an up‐regulation of the inflammatory response pathway, the pathways involved in oxidative metabolism were significantly down‐regulated during the chronic phase of arthritis. Since oxidative metabolism determines the mode of macrophage activation, we investigated phenotype switching in macrophages. Markers of alternatively activated macrophages, such as arginase 1, were at maximal levels during acute inflammation. In contrast, induction of markers of classically activated macrophages (M1), such as interleukin‐1β (IL‐1β) and inducible nitric oxide synthase (iNOS), was relatively low during the acute phase of disease, but highly increased toward the chronic phase. M1 polarization during the chronic phase was accompanied by a Th1 signature, characterized by IL‐12p40, IL‐12p35, and interferon‐γ. However, the absence of IL‐12p40, but not IL‐12p35, significantly inhibited the chronic phase of arthritis and was marked by a reduction in IL‐17 and iNOS levels, as well as restored expression of oxidative metabolism genes.

Conclusion

M1 polarization accompanied by a decline in oxidative metabolism determine the chronic phase of arthritis. IL‐12p40, most likely acting through the IL‐23/IL‐17 axis, plays a critical role in this process.
Illness perceptions in patients with fibromyalgia and their relationship to quality of life and catastrophizing
Authors: van Wilgen C. Paul , van Ittersum Miriam W. , Kaptein Ad A. , van Wijhe Marten
Published: October 2008

Objective

In the last decade, illness perceptions have been identified as important in the treatment of fibromyalgia (FM). The aim of the present study was to examine illness perceptions and use of the revised Illness Perception Questionnaire in patients with FM (IPQ‐R‐FM) and their relationship to quality of life and catastrophizing.

Methods

A domain with specific causal attributions related to FM was added to the IPQ‐R‐FM. The psychometric properties of the IPQ‐R‐FM dimensions and attribution scales were examined. The causal domain, in which patients describe the most important perceived causes for their FM, was analyzed. To analyze the relationship with quality of life and catastrophizing, the Fibromyalgia Impact Questionnaire and the Pain Catastrophizing Scale were used.

Results

Fifty‐one outpatients completed the questionnaires on 2 occasions, 3 weeks apart. FM was considered to be chronic and to have serious consequences; patients perceived little personal control and did not expect medical treatment to be effective. The psychometric properties of the IPQ‐R‐FM were found to be adequate. Patients most frequently attributed the causes of FM to an external somatic source (58%). Quality of life was related to experiencing more consequences attributable to FM. Catastrophizing was related to a limited understanding of the symptoms of FM, the more cyclical nature of FM, and an emotional representation.

Conclusion

The IPQ‐R‐FM is a useful tool to assess illness perceptions in patients with FM. Illness perceptions are related to quality of life and catastrophizing; therefore, it seems important to assess and integrate illness perceptions into the management of patients with FM.
Reliability and validity of the myositis disease activity assessment tool
Authors: Sultan Shabina M. , Allen Elizabeth , Oddis Chester V. , Kiely Patrick , Cooper Robert G. , Lundberg Ingrid E. , Vencovsky Jiri , Isenberg David A.
Published: October 2008

Objective

To test the interrater reliability and validity of the Myositis Disease Activity Assessment Tool, which consists of the Myositis Intention‐to‐Treat Activity Index and the Myositis Disease Activity Assessment Visual Analog Scales.

Methods

Two phases of the study were conducted to assess the reliability and validity of the tool, which was modified following the first phase. In the first phase of the reliability study, 123 adult myositis patients were evaluated in 7 centers, and in the second phase 40 patients were evaluated in 2 centers. The validity study included 294 patients in 5 centers in the first phase and 65 patients in 3 centers in the second phase. The interrater reliability was assessed using intraclass correlation coefficients. The criterion validity was calculated using sensitivity, specificity, and positive predictive value (PPV) of a grade of A in any system. Spearman's rank correlation coefficient was used to measure the convergent validity of cross‐sectional scores between the 2 instruments.

Results

There was a 2:1 ratio of female to male patients. There was no significant difference in mean age at diagnosis (46.3 versus 46.8 years) and mean disease duration (7.7 versus 10 years) between the 2 groups recruited for the different phases of the study. There was an improvement in interrater reliability in the second phase of the study. There was a significant improvement in the validity of the assessment tool following modification of the tool. The sensitivity, specificity, and PPV of a grade of A in any system improved from 86%, 92%, and 67% in the first phase to 96%, 94%, and 83%, respectively, in the second phase. Convergent validity between the 2 activity tools showed good correlation, ranging from 0.8 to 0.94, for the individual organ systems.

Conclusion

This is the first major attempt to assess the reliability and validity of a disease activity index in myositis. Our findings indicate that, following within‐study modification, the tool appears to be a reliable and valid instrument to assess myositis disease activity.
Certolizumab pegol plus methotrexate is significantly more effective than placebo plus methotrexate in active rheumatoid arthritis: Findings of a fifty‐two–week, phase III, multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group study
Authors: Keystone Edward , Heijde Désireé Van Der , Mason David , Landewé Robert , Vollenhoven Ronald Van , Combe Bernard , Emery Paul , Strand Vibeke , Mease Philip , Desai Chintu , Pavelka Karel
Published: October 2008

Objective

To evaluate the efficacy and safety of 2 dosage regimens of lyophilized certolizumab pegol (a novel PEGylated anti–tumor necrosis factor agent) as adjunctive therapy to methotrexate (MTX) in patients with active rheumatoid arthritis (RA) with an inadequate response to MTX therapy alone.

Methods

In this 52‐week, phase III, multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group trial, 982 patients were randomized 2:2:1 to receive treatment with subcutaneous certolizumab pegol at an initial dosage of 400 mg given at weeks 0, 2, and 4, with a subsequent dosage of 200 mg or 400 mg given every 2 weeks, plus MTX, or placebo plus MTX. Co‐primary end points were the response rate at week 24 according to the American College of Rheumatology 20% criteria for improvement (ACR20) and the mean change from baseline in the modified total Sharp score at week 52.

Results

At week 24, ACR20 response rates using nonresponder imputation for the certolizumab pegol 200‐mg and 400‐mg groups were 58.8% and 60.8%, respectively, as compared with 13.6% for the placebo group. Differences in ACR20 response rates versus placebo were significant at week 1 and were sustained to week 52 (P < 0.001). At week 52, mean radiographic progression from baseline was reduced in patients treated with certolizumab pegol 200 mg (0.4 Sharp units) or 400 mg (0.2 Sharp units) as compared with that in placebo‐treated patients (2.8 Sharp units) (P < 0.001 by rank analysis). Improvements in all ACR core set of disease activity measures, including physical function, were observed by week 1 with both certolizumab pegol dosage regimens. Most adverse events were mild or moderate.

Conclusion

Treatment with certolizumab pegol 200 or 400 mg plus MTX resulted in a rapid and sustained reduction in RA signs and symptoms, inhibited the progression of structural joint damage, and improved physical function as compared with placebo plus MTX treatment in RA patients with an incomplete response to MTX.
A potential role of thymic stromal lymphopoietin in the recruitment of macrophages to mouse intervertebral disc cells via monocyte chemotactic protein 1 induction: Implications for herniated discs
Authors: Ohba Tetsuro , Haro Hirotaka , Ando Takashi , Koyama Kensuke , Hatsushika Kyosuke , Suenaga Fumiko , Ohnuma Yuko , Nakamura Yuki , Katoh Ryohei , Ogawa Hideoki , Hamada Yoshiki , Nakao Atsuhito
Published: October 2008

Objective

To determine whether thymic stromal lymphopoietin (TSLP) plays a role in the resorption of herniated disc tissue.

Methods

The expression of TSLP messenger RNA (mRNA) and protein in mouse intervertebral disc cells was assessed by quantitative real‐time polymerase chain reaction, enzyme‐linked immunosorbent assay (ELISA), and immunohistochemical analysis. The ability of mouse intervertebral disc cells to respond to TSLP stimulation was examined by Western blot analysis, ELISA, and protein array analysis. Intracellular signaling pathways involved in TSLP signaling in mouse intervertebral disc cells were investigated using several chemical inhibitors. The role of TSLP in macrophage migration into the intervertebral disc was assessed by in vitro migration assay. Finally, TSLP expression in clinical specimens derived from patients with a herniated disc was examined by immunohistochemistry.

Results

Mouse intervertebral disc cells expressed TSLP mRNA and protein upon stimulation with NF‐κB–activating ligands such as tumor necrosis factor α. In addition, the mouse intervertebral disc cells expressed the TSLP receptor and produced monocyte chemotactic protein 1 (MCP‐1; CCL2) and macrophage colony‐stimulating factor in response to TSLP stimulation. Both anulus fibrosus and nucleus pulposus intervertebral disc cells expressed MCP‐1 upon TSLP stimulation, which was mediated via the phosphatidylinositol 3‐kinase/Akt pathway. Consistently, the supernatants of TSLP‐activated intervertebral disc cultures had the capacity to induce macrophage migration in an MCP‐1–dependent manner. Finally, TSLP and MCP‐1 were coexpressed in human herniated disc specimens in which macrophage infiltration into the tissue was observed.

Conclusion

TSLP induced by NF‐κB–activating ligands in intervertebral discs may contribute to the recruitment of macrophages to the intervertebral disc by stimulating MCP‐1 production and may be involved in the resorption of herniated disc tissue.
Mature antigen‐experienced T helper cells synthesize and secrete the B cell chemoattractant CXCL13 in the inflammatory environment of the rheumatoid joint
Authors: Manzo Antonio , Vitolo Barbara , Humby Frances , Caporali Roberto , Jarrossay David , Dell'Accio Francesco , Ciardelli Laura , Uguccioni Mariagrazia , Montecucco Carlomaurizio , Pitzalis Costantino
Published: October 2008

Objective

Synovial B cells play a critical role in rheumatoid arthritis (RA), being involved in autoantibody synthesis, T cell activation, and cytokine production. CXCL13 is a B cell chemoattractant that is instrumental in synovial B cell organization; the regulatory determinants of CXCL13 in inflammation are poorly characterized. This study was undertaken to investigate the functional involvement of synovial T cells in the ectopic expression of CXCL13 in RA.

Methods

CXCL13 production and regulation were addressed using immunohistochemistry, in situ hybridization, quantitative polymerase chain reaction, multicolor flow cytometry, and enzyme‐linked immunosorbent assay, by in situ–ex vivo analysis and in vitro functional assays with rheumatoid synovial tissue and primary cells.

Results

CXCL13 messenger RNA and protein expression and spontaneous CXCL13 secretion were detected in RA synovial fluid T cells but were not detected (or were detected only occasionally) in peripheral blood T cells. Analysis of tissue expression confirmed cytoplasm localization of CXCL13 in T lymphocytes infiltrating B cell follicles and small perivascular aggregates. Multicolor characterizations in synovial fluid demonstrated CXCL13 expression in antigen‐experienced T helper cells, frequently characterized by terminal differentiation and the lack of the follicular helper T cell markers CXCR5 and BCL6 protein. In vitro functional assays revealed the enhancing effect of T cell receptor–CD28 engagement on CXCL13 production and secretion in primary cells.

Conclusion

Our findings define a new functional property of synovial T cells, demonstrating their active involvement in the local production of B cell chemoattractants, and support a direct contribution of the adaptive immune system and antigen‐dependent signals in the mechanisms of B cell localization in RA.
Toll‐like receptor 2 variants are associated with acute reactive arthritis
Authors: Tsui Florence W. L. , Xi Nancy , Rohekar Sherry , Riarh Reena , Bilotta Rose , Tsui Hing Wo , Inman Robert D.
Published: October 2008

Objective

We previously reported a recent outbreak of salmonellosis in which some individuals developed complications of the enteric infection. The objective of this study was to identify genetic variants that might predispose infected individuals to develop articular and/or extraarticular sequelae after Salmonella enteritidis infection.

Methods

The entire exposed cohort was invited to participate in the study by sending a saliva sample for DNA analysis. Seventy‐five Salmonella‐infected subjects for whom there was clinical information agreed to participate and were stratified into 4 groups. Group 1 patients had arthritis and extraarticular features, group 2 patients had arthritis alone, group 3 patients had extraarticular features alone, and group 4 patients had neither. DNA samples from an uninfected cohort of 91 normal subjects were also genotyped. Genotyping was performed using 2 Toll‐like receptor 2 (TLR‐2) (rs5743708 and rs5743704) and 2 TLR‐4 (rs4986790 and rs4986791) single‐nucleotide polymorphisms (SNPs). Statistical analyses were carried out using chi‐square tests.

Results

There was no association of TLR‐4 exonic variants with any clinical events that were reported as accompanying the Salmonella infection. In contrast, compared with normal controls, one of the rare TLR‐2 SNPs (rs5743708, R753Q) was associated with the development of arthritis and extraarticular features (P = 0.015 by chi‐square test). The TLR‐2 variant 753Q was not detected in any of the infected individuals with an uncomplicated course. Another TLR‐2 variant, 631H, was associated with articular symptoms in infected males (P = 0.03 by chi‐square test).

Conclusion

In this outbreak, genetic variants of TLR‐2, but not TLR‐4, were associated with acute reactive arthritis following infection with S enteritidis.
Angiogenesis in systemic sclerosis: Impaired expression of vascular endothelial growth factor receptor 1 in endothelial progenitor–derived cells under hypoxic conditions
Authors: Avouac J. , Wipff J. , Goldman O. , Ruiz B. , Couraud P. O. , Chiocchia G. , Kahan A. , Boileau C. , Uzan G. , Allanore Y.
Published: October 2008

Objective

To assess angiogenesis and explore the expression and regulation of vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR‐1), and VEGFR‐2, the leading mediators of angiogenesis, in SSc patients and controls.

Methods

Late‐outgrowth endothelial progenitor cells (EPCs), isolated from the peripheral blood of systemic sclerosis (SSc) patients and controls, and human umbilical vein endothelial cells (HUVECs) were assessed under normal and hypoxic conditions. Genomic background was evaluated in a large case–control study (including 659 patients with SSc and 511 controls) using tag single‐nucleotide polymorphisms on VEGFR1 and VEGFR2 genes.

Results

EPCs from SSc patients had the phenotype of genuine endothelial cells and displayed in vitro angiogenic properties similar to those of HUVECs and control EPCs under basal conditions, as determined by flow cytometry, tube formation, and migration assay. However, after 6 hours of hypoxic exposure, EPCs from SSc patients exhibited lower induced expression of VEGFR‐1 at the messenger RNA and protein levels, but similar VEGF and VEGFR‐2 expression, compared with HUVECs or EPCs from healthy controls. There was no evidence of defective expression of hypoxia‐inducible factor 1α. These results were supported by the lower serum levels of soluble VEGFR‐1 found in SSc patients (n = 187) compared with healthy controls (n = 48) (mean ± SD 163.7 ± 98.5 versus 210.4 ± 109.5 pg/ml; P = 0.0042). These abnormalities did not seem to be related to genomic background.

Conclusion

Our findings shed new light on the possible role of VEGFR‐1 in the main vascular disturbances that occur in SSc and lead to more severe disease.
HMOX1 promoter polymorphism modulates the relationship between disease activity and joint damage in rheumatoid arthritis
Authors: Wagener Frank A. D. T. G. , Toonen Erik J. M. , Wigman Lonneke , Fransen Jaap , Creemers Marjonne C. W. , Radstake Timothy R. D. J. , Coenen Marieke J. H. , Barrera Pilar , van Riel Piet L. C. M. , Russel Frans G. M.
Published: October 2008

Objective

The guanine‐thymidine (GT)n repeat in the HMOX1 promoter determines the level of induction of the heme‐degrading enzyme heme oxygenase 1 (HO‐1), which protects against inflammatory and oxidative stress. In individuals with short (GT)n repeats (where n < 25; SS genotype), higher levels of HO‐1 activity are induced more rapidly than in those with long (GT)n repeats (where n ≥ 25; LL genotype). Recently, it was demonstrated that HO‐1 activity protects against the onset of rheumatoid arthritis (RA). The aim of this study was to determine whether the (GT)n‐repeat length within the HMOX1 promoter region is associated with RA disease severity and radiographic joint damage.

Methods

A cohort of 325 well‐characterized RA patients and 273 controls was investigated by DNA fragment‐length analysis for the association of (GT)n repeats in the HMOX1 promoter region with RA disease susceptibility and severity.

Results

Although no significant differences in genotype or allele frequency were found between controls and RA patients, the odds ratios corresponded well to those in the previously described cohort. Among patients, those carrying the SS genotype had a more favorable radiographic outcome over 9 years than those carrying the LL genotype. This was unexpected since no differences in disease activity were found between the genotypes or alleles.

Conclusion

Patients with the SS genotype have a better long‐term radiographic outcome despite poor prognostic markers at baseline and despite disease activity at followup similar to that of patients with the LL genotype. This suggests that the HMOX1/HO‐1 system is involved in the uncoupling of disease activity and joint damage and may provide a novel target for the treatment of RA.
Acetylcholine regulation of synoviocyte cytokine expression by the α7 nicotinic receptor
Authors: Waldburger Jean‐Marc , Boyle David L. , Pavlov Valentin A. , Tracey Kevin J. , Firestein Gary S.
Published: October 2008

Objective

The central nervous system can regulate peripheral inflammation, but the efferent neuronal routes and the mediators remain poorly defined. One candidate is the cholinergic pathway, which releases acetylcholine (ACh). This neurotransmitter can bind to the α7 cholinergic receptor (α7R) expressed by nonneuronal cells and reduce inflammation. To test this possibility, we evaluated the expression of α7R and its potential role as a target in rheumatoid arthritis (RA).

Methods

The expression of α7R in human synovium and fibroblast‐like synoviocytes (FLS) was determined using immunohistochemical, Western blot, and quantitative polymerase chain reaction (PCR) analyses. The effects of ACh in vitro were determined in interleukin‐1 (IL‐1)–stimulated FLS using immunoassays for protein, quantitative PCR for messenger RNA (mRNA), luciferase reporter constructs for IL‐6 and NF‐κB promoter activity, and electrophoretic mobility shift assays. Expression of α7R was knocked down with small interfering RNA (siRNA) or was inhibited with the selective α7R antagonist methyllycaconitine (MLA).

Results

Protein and mRNA for α7R were demonstrated in RA and osteoarthritis synovium and cultured synoviocytes. Expression in synovium was mainly in the intimal lining. ACh significantly reduced the production of IL‐6, CXCL8, CCL2, CCL3, CCL5, and granulocyte colony‐stimulating factor by IL‐1–stimulated FLS. This effect was blocked by the α7R antagonist MLA or by using α7R siRNA to knock down receptor expression. The selective α7R agonist PNU‐282,987 decreased the production of IL‐6 by IL‐1–stimulated FLS. ACh did not reduce IL‐6 transcription, but it decreased IL‐6 mRNA half‐life and reduced IL‐6 mRNA steady‐state levels.

Conclusion

The α7 receptor is expressed in the synovium and by synoviocytes. Receptor ligation inhibits cytokine expression in FLS through a posttranscriptional mechanism. Therefore, α7R is a potential therapeutic target for inflammatory diseases.
Vertebral strength changes in rheumatoid arthritis patients treated with alendronate, as assessed by finite element analysis of clinical computed tomography scans: A prospective randomized clinical trial
Authors: Mawatari Taro , Miura Hiromasa , Hamai Satoshi , Shuto Toshihide , Nakashima Yasuharu , Okazaki Ken , Kinukawa Naoko , Sakai Shuji , Hoffmann Paul F. , Iwamoto Yukihide , Keaveny Tony M.
Published: October 2008

Objective

Finite element analysis of clinical computed tomography (CT) scans provides a noninvasive means of assessing vertebral strength that is superior to dual x‐ray absorptiometry (DXA)–measured areal bone mineral density. The present study was undertaken to compare strength changes, measured using this newer method, in rheumatoid arthritis (RA) patients who were treated with alendronate (ALN) versus those who were not.

Methods

Thirty female RA patients without radiologic signs of L3 compression fractures or a history of osteoporosis medication were enrolled in a prospective randomized clinical trial. Patients were randomly assigned to the ALN group (5 mg orally, once daily) or the control group not receiving antiresorptive treatment. All patients were evaluated by DXA and quantitative CT at baseline and reevaluated after a mean of 12.2 months. Nonlinear finite element analysis was performed on the CT scans (n = 29 available for analysis) to compute an estimate of vertebral compressive strength and to assess strength changes associated with changes in the trabecular compartment and the outer 2 mm of bone (peripheral compartment).

Results

On average, vertebral strength was significantly decreased from baseline in the control group (n = 15) (median change −10.6%; P = 0.008) but was maintained in the ALN group (n = 14) (median change +0.4%; P = 0.55), with a significant difference between the 2 groups (P < 0.01). Strength decreased more rapidly within the trabecular bone, and ALN treatment was much more effective in the peripheral than the trabecular compartment.

Conclusion

Our results indicate that patients with RA can lose a substantial amount of vertebral strength over a relatively short period of time, and this loss can be prevented by ALN, primarily via its positive effect on the outer 2 mm of vertebral bone.