bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of epoxy–montmorillonite nanocomposite
Authors: Chen K. H. , Yang S. M. 
Published: October 2002

AbstractTo synthesize an epoxy–montmorillonite nanocomposite, the intercalation of clay layers with acid onium ions {[H3N(CH2)n−1COOH]+, [H3N(CH2)n−1CH3]+, [H3N(CH2)−NH2]+, and [H3N(CH2)nNH3]2+} by different methods were studied. The intercalated clay was characterized by XRD, ICP, and CHN elemental analysis. An acid onium ion [H3N(CH2)17CH3]+ enlarged the d‐spacing of CWC–, AMS–, and Kunipia–montmorillonite to 21.6, 18.1, and 20.7 Å, respectively. The results of CHN elemental analysis confirmed that onium ions were intercalated between the clay layers. Ion exchange of montmorillonite with onium ions is a better way to intercalate more onium ions. Among those onium ions mentioned above, [H3N(CH2)nNH3]2+ displaced more sodium ions from the clay layers than did the others. An epoxy–montmorillonite nanocomposite was synthesized by heating a mixture of [H3N(CH2)17CH3]+–montmorillonite (CWC) with an epoxy monomer and curing agent. The nanocomposite was characterized by XRD, TEM, DSC, UV, TGA, and Instron testing. TEM photographs showed that the spacing between the clay layers was further enlarged to about 50 Å and no segregation between the clay particle and the polymer was observed. The glass transition temperature of the nanocomposite containing 20 phr of [H3N(CH2)17CH3]+–montmorillonite (CWC) increased from 108.4 to 146.1°C. Especially, the nanocomposite possesses higher water resistance than that of the epoxy resin or of the physical mixture of epoxy and montmorillonite (CWC). According to the transmittance measurement (λ = 550 nm), the nanocomposite shows good light transmittance. Although, we cannot improve the mechanical properties, improvements of other properties can be evidenced for the formation of nanoscale composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 414–421, 2002
Effect of degree of saponification on the rheological properties of syndiotactic poly(vinyl alcohol)/ water solution
Authors: Lyoo Won Seok , Seo In Seok , Yeum Jeong Hyun , Yoon Won Sik , Ji Byung Chul , Kim Bong Shik , Lee Sang‐Seob , Kim Byoung Chul 
Published: October 2002

AbstractTo identify the effect of degree of saponification (DS) of syndiotactic poly(vinyl alcohol)s (s‐PVA)s having similar tacticity and molecular weight on the rheological properties of s‐PVA/water solution, four kinds of (s‐PVA)s with assigned (DS)s, from 93.1 to 97.5%, were prepared by copolymerization of vinyl pivalate (VPi) and vinyl acetate (VAc), followed by saponifying the corresponding copoly(VPi/VAc). The DS played a significant role in rheological behavior. Over the frequency range of 10−1 to 102 rad/s s‐PVA with higher DS shows more shear thinning at similar molecular weight and tacticity of polymer, suggesting that PVA molecules are more readily oriented as DS increases. This may provide indirect evidence of the spontaneous in situ orientation of s‐PVA molecules at the late stage of saponification. Yield stress is higher for s‐PVA with higher DS at similar molecular weight and tacticity of s‐PVA. This indicates that more domains with internal order are produced at higher saponification. These facts result from increase in stiffness of s‐PVA molecules with proceeding the saponification reaction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 463–467, 2002
Bone density of the arm and forearm as an age indicator in specimens of stranded striped dolphins (stenella coeruleoalba)
Authors: Guglielmini Carlo , Zotti Alessandro , Bernardini Daniele , Pietra Marco , Podestá Michela , Cozzi Bruno 
Published: October 2002

AbstractThe age of odontocetes living in the wild is determined mainly by analysis of dentine layers in sections of the teeth. We examined a series of specimens from striped dolphins (Stenella coeruleoalba, Meyen, 1833) that had stranded along the Italian coast of the Mediterranean sea. The present study analyzes and describes bone density in the arm and forearm of the stranded specimens, and correlates the data with total body length of the animal and age as determined by the number of dentine layers in sections of the teeth. According to our model, age can be predicted on the basis of bone density and total body length of the stranded animal. This is the first study to use bone density as a biological parameter to understand the wear and tear of life in the sea. The results suggest that bone density is a new tool for recording age in wild odontocetes. Anat Rec 267:225–230, 2002. © 2002 Wiley‐Liss, Inc.
Dosimetry implications of upper tracheobronchial airway anatomy in two mouse varieties
Authors: Oldham Michael J. , Phalen Robert F. 
Published: October 2002

AbstractStrain‐ and variety‐related differences in responses of mice have been reported for a variety of inhaled particulate and gaseous materials. It is important to understand the potential contributions to such responses of differences in delivered doses to the respiratory tract as well as differences in biochemical processes. Deposition doses of inhaled particles are influenced by several factors, including airway anatomy, ventilation, and particle characteristics. Tracheobronchial airway morphometry for airway generations 1–6 of the BALB/c mouse was generated using replica lung casts prepared in situ. Measurements were performed on two groups: control and ovalbumin‐sensitized male BALB/c mice. These measurements were compared with previously published airway morphometry of male B6C3F1 mice. Sensitization did not significantly change measured airway dimensions in the BALB/c mouse. However, the two mouse varieties had significant differences in airway anatomy. The differences found in airway anatomy between mouse varieties correlated with differences in body length and chest circumference. Particle deposition predictions for both varieties of mice were performed for unit density spherical particles from 0.1 to 10 μm in diameter at two ventilation rates using a published aerosol dosimetry computer code. Particle deposition in the proximal tracheobronchial tree ranged up to 3 times greater for the BALB/c mouse for a 2 μm particle diameter and high ventilation rate. These differences in predicted particle deposition suggest that observed strain and variety differences in response to inhaled particulate matter may be in part due to differences in delivered doses to the respiratory tract. Anat Rec 268:59–65, 2002. © 2002 Wiley‐Liss, Inc.
Nitric oxide synthase in the frog cerebellum: Response of Purkinje neurons to unilateral eighth nerve transection
Authors: Pisu Maria Bonaria , Conforti Elena , Botta Laura , Valli Paolo , Bernocchi Graziella 
Published: October 2002

AbstractWhen vestibular damage occurs, nitric oxide synthase (NOS) expression in rat cerebellar flocculus is affected. Since compensation for postural symptoms occurs and Purkinje cells play an important role in movement coordination and motor learning, we analyzed in situ the induction of NOS in the Purkinje cell population of the cerebellum (corpus cerebelli) of frog after unilateral transection of the eighth statoacoustic nerve to gain insight into the role of NO in neural plasticity after injury. Three days after neurectomy, the early effects induced NADPH diaphorase reactivity in most of the Purkinje cells on the ipsilateral side, while on the contralateral side the highest labeling was observed at 15 days. This finding can give information on the dynamics of vestibular compensation, in which NOS involvement was investigated. At 30 days, NADPH diaphorase reactivity was present in a large number of Purkinje cells of the whole cerebellum, while at 60 days a down‐regulation for NADPH diaphorase reactivity was evident. A similar trend was observed for NOS‐immunoreactivity, which was still present at 60 days in a high percentage of Purkinje cells, mainly on the ipsilateral side. On the basis of cell density evaluations, it was proposed that the early induction of NOS after neurectomy was linked to the degeneration of a part of the Purkinje neurons, while the permanence of NOS labeling might be due to a neuroprotective role of NO in the restoration phase of the vestibular compensation process. Anat Rec 268:73–83, 2002. © 2002 Wiley‐Liss, Inc.
Increased life span of human osteoarthritic chondrocytes by exogenous expression of telomerase
Authors: Piera‐Velazquez Sonsoles , Jimenez Sergio A. , Stokes DavidG. 
Published: October 2002

AbstractObjectiveTo extend the life span of human osteoarthritic (OA) articular chondrocytes by introduction of the catalytic component of human telomerase while preserving the chondrocyte‐specific phenotype.MethodsHuman articular chondrocytes were isolated from the femoral head and tibial plateau of patients undergoing knee joint replacement for OA. The chondrocytes were cultured as monolayers and infected with a retroviral telomerase expression construct followed by selection with G418 for 10–14 days. Telomeric‐repeat amplification protocol assays and telomere terminal restriction fragment length assays were performed on pools of transduced cells in order to measure telomerase activity and telomere length. Growth kinetics and population doubling capacity were assessed by passaging the cells in monolayer culture. Redifferentiation of the monolayer chondrocyte cultures was induced by transfer to suspension culture on poly‐(2‐hydroxyethyl‐methacrylate) (polyHEMA)–coated dishes. Induction of the chondrocyte‐specific phenotype was monitored by analysis of gene expression utilizing reverse transcription–polymerase chain reaction.ResultsOA chondrocytes isolated from 3 different donors (ages 41, 69, and 75 years) were transduced with a retroviral construct expressing telomerase. After selection, pooled populations of cells from all donors and a clonal cell line from 1 donor expressed telomerase activity and exhibited lengthening of telomeres. Chondrocytes expressing telomerase showed an increase of 5–9 population doublings over 234 days of culture in monolayer. The telomerase‐transduced cells recovered a chondrocyte‐specific gene expression pattern following culture on polyHEMA‐coated dishes.ConclusionThe exogenous expression of telomerase may represent a way to expand human OA chondrocytes while allowing maintenance of the chondrocyte‐specific phenotype. These cells have the potential to be used for restoration of the articular cartilage defects occurring in this disease.
Assessment of vascular function in systemic sclerosis: Indications of the development of nitrate tolerance as a result of enhanced endothelial nitric oxide production
Authors: Andersen Grethe Neumann , Mincheva‐Nilsson Lucia , Kazzam Elsadig , Nyberg Gunnar , Klintland Natalia , Petersson Ann‐Sofi , Rantapää‐Dahlqvist Solbritt , Waldenström Anders , Caidahl Kenneth 
Published: October 2002

AbstractObjectiveTo investigate the relationship between endothelium‐dependent and endothelium‐independent functions and the stiffness of conduit arteries as well as levels of endothelial activation markers in patients with systemic sclerosis (SSc).MethodsEndothelium‐dependent (i.e., flow‐mediated) and endothelium‐independent (i.e., nitroglycerin‐induced) dilation of the brachial artery was measured as the percentage of change from baseline (FMD% and NTG%, respectively) in 24 SSc patients and 24 age‐ and sex‐matched healthy controls by high‐resolution ultrasound imaging. The maximum increase in systolic pressure per unit of time (dP/dtmax), as a measure of arterial wall stiffness, was assessed in the radial artery by pulse applanation tonometry. Plasma nitrate, the most important metabolite of nitric oxide, and 24‐hour urinary excretion of nitrate were measured by gas chromatography mass spectrometry. Soluble E‐selectin and soluble vascular cell adhesion molecule 1 (sVCAM‐1) were measured by enzyme‐linked immunosorbent assay.ResultsBrachial artery FMD% and NTG% did not differ between SSc patients and controls. Radial artery dP/dtmax was significantly increased in the patients and correlated significantly with elevated levels of plasma nitrate and sVCAM‐1. Twenty‐four‐hour urinary nitrate excretion tended to be elevated. Brachial artery NTG% was significantly inversely correlated with levels of plasma nitrate and soluble endothelial adhesion molecules.ConclusionThe ability of the brachial arteries to dilate in response to hyperemia and nitroglycerin challenge is preserved in SSc. Stiffness of the radial artery is increased, however. Endothelial activation seems to determine the extent of the brachial artery NTG% and the radial artery dP/dtmax. The data are compatible with the hypothesis that nitrate tolerance is present in the vascular smooth muscle cells of the brachial artery wall in SSc.
The α5β1 integrin provides matrix survival signals for normal and osteoarthritic human articular chondrocytes in vitro
Authors: Pulai Judit I. , Del Carlo Marcello , Loeser Richard F. 
Published: October 2002

AbstractObjectiveChondrocyte cell death may play an important role in the development of arthritis. The goal of the present study was to evaluate the role of the extracellular matrix (ECM) in promoting chondrocyte survival via signals through the integrin family of ECM receptors.MethodsChondrocytes were isolated by sequential enzymatic digestion from normal ankle cartilage of organ donors and from osteoarthritic (OA) knee tissue obtained from patients undergoing total knee replacement. Cell survival in monolayer and in suspension culture was measured using fluorescent labels after treatment with specific integrin‐blocking antibodies and echistatin, a disintegrin peptide. A quantitative enzyme‐linked immunosorbent assay for histone‐associated DNA fragments and morphologic evaluation by electron microscopy were used to evaluate apoptosis.ResultsFreshly isolated chondrocytes died when plated in serum‐free media at low density on poly‐L‐lysine, but showed >95% survival on fibronectin (FN). A monoclonal blocking antibody to the α5‐integrin subunit (FN receptor) significantly inhibited survival on FN, whereas control antibodies had no effect. Likewise, treatment of freshly isolated chondrocytes in serum‐free alginate‐suspension culture with the α5‐blocking antibody resulted in cell death in a dose‐dependent manner, with 20 μg/ml of the antibody reducing normal chondrocyte survival to 20% of that in controls, and OA chondrocyte survival to 23% of that in controls. Antibody inhibition of αv and α1 integrins or treatment with echistatin did not cause cell death. Addition of insulin‐like growth factor 1 (IGF‐1; 100 ng/ ml) was not able to improve survival of α5‐antibody–treated cells. However, treatment with 10% fetal bovine serum improved normal chondrocyte survival to 98% (a 5.1‐fold increase) and OA chondrocyte survival to 64% (a 2.8‐fold increase). Cell death due to α5 inhibition was associated with apoptosis.ConclusionThese results demonstrate that chondrocyte survival signals are transmitted via the α5β1 FN receptor. Inhibition of matrix survival signals mediated by α5β1 also inhibits the ability of IGF‐1 to promote survival, suggesting that IGF‐1–mediated survival signaling may require a cosignal from α5β1.
Underutilization of gastroprotective measures in patients receiving nonsteroidal antiinflammatory drugs
Authors: Smalley Walter , Stein C. Michael , Arbogast Patrick G. , Eisen Glenn , Ray Wayne A. , Griffin Marie 
Published: October 2002

AbstractObjectiveTo determine the frequency of use of recommended gastroprotective strategies in a cohort of patients receiving recurrent treatment with nonsteroidal antiinflammatory drugs (NSAIDs).MethodsA cross‐sectional study was performed using administrative data from the Tennessee Medicaid (TennCare) program. The study population consisted of 76,765 recurrent recipients of NSAIDs (NSAID users), comprising 24% of the 319,402 persons ages 50 years or older enrolled in the TennCare program from January 1999 through June 2000. Frequency of use of either of 2 recommended gastroprotective strategies, involving either traditional NSAIDs combined with recommended anti‐ulcer cotherapy or use of a selective cyclooxygenase 2–inhibiting drug (coxib), was measured and categorized by risk for ulcer complication.ResultsAmong this cohort of recurrent NSAID users, 16% received 1 of the 2 recommended gastroprotective therapies: 10% received traditional NSAIDs along with antiulcer drugs at the recommended doses and 6% received coxibs. Among those patients with ≥2 risk factors for ulcer complications (age 75 years or older, peptic ulcer or gastrointestinal bleeding in the past year, or concurrent use of oral anticoagulants or corticosteroids), 30% received such gastroprotective therapy.ConclusionUse of recommended strategies to decrease ulcer complications in vulnerable populations is relatively uncommon.
Systemic lupus erythematosus in three ethnic groups. XI. Sources of discrepancy in perception of disease activity: A comparison of physician and patient visual analog scale scores
Authors: Alarcón Graciela S. , McGwin Gerald , Brooks Kemi , Roseman Jeffrey M. , Fessler Barri J. , Sanchez Martha L. , Bastian Holly M. , Friedman Alan W. , Baethge Bruce A. , Reveille John D. ,   LUMINA STUDY GROUP
Published: October 2002

AbstractObjectiveTo compare patient's and physician's assessment of disease activity in a multiethnic (Hispanic, African American, and Caucasian) cohort of systemic lupus erythematosus (SLE) patients.MethodsThree hundred patients with SLE from the LUMINA (Lupus in Minority populations: Nature versus nurture) cohort were included. Disease activity was assessed with the Systemic Lupus Activity Measure (SLAM); patients and physicians assessed disease activity using a 10‐cm anchored visual analog scale (VAS). The difference between VAS scores was termed discrepancy (>1 cm was considered a priori clinically relevant). Selected sociodemographic, clinical, behavioral, and psychological variables were examined in relation to discrepancy in univariable and multivariable models adjusting for the physician global VAS score in order to eliminate ceiling and floor effects.ResultsA discrepancy was exhibited by 58% of the patients. Abnormal laboratory findings were negatively associated with discrepancy, and poor self‐perceived functioning and joint involvement were positively associated with discrepancy. Ethnicity did not account for discrepant perception of disease activity.ConclusionPatients and physicians rate disease activity in SLE differently. Physicians appear to place more emphasis on laboratory features while patients place more emphasis on function.
Cartilage‐specific constitutive expression of TSG‐6 protein (product of tumor necrosis factor α–stimulated gene 6) provides a chondroprotective, but not antiinflammatory, effect in antigen‐induced arthritis
Authors: Glant Tibor T. , Kamath Rajesh V. , Bárdos Tamás , Gál István , Szántó Sándor , Murad Yanal M. , Sandy John D. , Mort John S. , Roughley Peter J. , Mikecz Katalin 
Published: October 2002

AbstractObjectiveTo study the chondroprotective effect of constitutively expressed TSG‐6 protein (tumor necrosis factor α–induced protein 6; Tnfip6) in cartilage, using antigen‐induced arthritis (AIA) in mice.MethodsTransgenic mice constitutively expressing TSG‐6 protein in cartilage were generated. Cartilage‐specific constitutive expression of TSG‐6 protein was confirmed by in situ hybridization, Western blot analysis, and immunohistochemistry. Control and transgenic mice were immunized with methylated bovine serum albumin (mBSA), and arthritis was induced by the intraarticular injection of mBSA. Mice were monitored up to day 35 after the challenge, and knee joint sections were examined for loss of cartilage proteoglycan (aggrecan) using Safranin O staining and antibodies to neoepitopes generated by various metalloproteinases (MPs). The loss of aggrecan in Safranin O–stained sections was quantified by morphometric methods.ResultsTsg6/tnfip6 transgenic mice constitutively expressed tsg6/tnfip6 messenger RNA and corresponding TSG‐6 protein in cartilage from embryonic life through adulthood, without any phenotypic abnormalities. These mice were used for AIA studies. Intraarticular injection of mBSA uniformly induced severe inflammation both in control (wild‐type and an irrelevant transgenic line) mice and in tsg6/tnfip6 transgenic mice. In contrast to the mBSA‐injected knee joints of control animals that were heavily damaged from day 5, the cartilage of transgenic mice that constitutively expressed TSG‐6 protein remained intact for at least 1 week, and this was followed by a relatively reduced loss of aggrecan. Concomitant with the loss of aggrecan, MP‐generated neoepitopes accumulated in unprotected joints. By day 35, the proteoglycan content returned to nearly normal levels in tsg6/tnfip6 transgenic mice, whereas it remained low in MP‐damaged knee cartilage of control mice.ConclusionTSG‐6 protein is known to form a complex with inter‐α–inhibitor (IαI), a potent serine protease inhibitor, which may be immobilized via the hyaluronan (HA)–binding domain of TSG‐6 protein in the HA‐rich extracellular matrix of cartilage. Thus, the local accumulation of TSG‐6 protein and TSG‐6 protein–bound IαI in tsg6/tnfip6 transgenic mice may inhibit serine proteases and subsequent activation of MPs. It is suggested that this mechanism might protect cartilage from extensive degradation even in the presence of acute inflammation.
HLA–B27 modulates nuclear factor κB activation in human monocytic cells exposed to lipopolysaccharide
Authors: Penttinen Markus A. , Holmberg Carina I. , Sistonen Lea , Granfors Kaisa 
Published: October 2002

AbstractObjectiveTo study whether HLA–B27 modifies some key factors controlling inflammatory responses on lipopolysaccharide (LPS) stimulation in human monocytic cells.MethodsU937 human monocytic cells were stably transfected with either HLA–B27 genomic DNA, HLA–B27 complementary DNA, HLA–A2 genomic DNA, or with the resistant vector pSV2neo (mock) alone. The cells were stimulated with LPS. Electrophoretic mobility shift assay was performed to determine nuclear factor κB (NF‐κB) and heat‐shock factor 1 activities, Western blotting was performed to detect the expressions of inhibitory κBα (IκBα) and heat‐shock proteins (HSPs), and enzyme‐linked immunosorbent assay was performed to measure tumor necrosis factor α (TNFα) secretion.ResultsThe expression of HLA–B27 modulated the response to LPS in U937 human monocytic cells. Stimulation with LPS led to faster degradation of IκBα regulatory proteins, accompanied by faster and prolonged activation of NF‐κB in HLA–B27–expressing cells compared with HLA–A2 and mock transfectants. The secretion of TNFα upon LPS stimulation correlated well with the activation of NF‐κB. No activation of the heat‐shock response was observed.ConclusionOur data indicate that HLA–B27 has effects on host responses to LPS that are unrelated to antigen presentation. Two crucial events in the development of arthritis, the activation of NF‐κB and the secretion of TNFα, were found to be enhanced in HLA–B27–expressing cells upon LPS stimulation. Because LPS is known to be present in the inflamed joints of patients with reactive arthritis (ReA), the enhanced inflammatory response of HLA–B27–positive cells upon LPS stimulation offers an attractive explanation for the role of HLA–B27 in the development of ReA.