bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of patient characteristics, disease variables, and HLA alleles on the development of radiographically evident sacroiliitis in juvenile idiopathic arthritis
Authors: Flatø Berit , Smerdel Anna , Johnston Virginia , Lien Gunhild , Dale Knut , Vinje Odd , Egeland Thore , Sørskaar Dag , Førre Øystein 
Published: August 2002

AbstractObjectiveTo assess the frequency of sacroiliitis and the radiographic and clinical outcome in juvenile idiopathic arthritis (JIA) and determine patient characteristics, early disease variables, and genetic markers that predict development of sacroiliitis.MethodsWe performed a retrospective cohort study of 314 (79%) of the 400 JIA patients first admitted to the hospital between 1980 and 1985. The participants were examined after a median disease duration of 14.9 years (range 11.7–25.1). Radiographs of the sacroiliac joints, hips, ankles, and tarsi were obtained and studied in a blinded manner by 2 radiologists. The presence of HLA–DRB1 and DPB1 alleles was determined by genotyping and that of HLA–B27 by serologic testing. Variables relating to the onset and course of the disease were obtained by chart reviews.ResultsTwenty (6%) of the JIA patients developed radiographic sacroiliitis according to the New York criteria. In 9 patients (45%), sacroiliitis had not been demonstrated before the followup examination. At followup, spinal flexion (lateral and anterior) was reduced in 70–75% of patients with sacroiliitis and in 30–35% of those without sacroiliitis. Compared with the JIA patients without sacroiliitis, those with sacroiliitis more frequently had inflammatory back pain, enthesitis, radiographic changes in the hips and calcanei, erosions of any peripheral joint, and uveitis.Predictors of sacroiliitis were HLA–B27, absence of DPB1*02, hip joint involvement within the first 6 months, and disease onset after age 8 years. The following factors were more common among patients in whom sacroiliitis developed than in other JIA patients: DRB1*04, male sex, family history of ankylosing spondylitis, psoriasis, inflammatory back pain, and enthesitis within the first 6 months.ConclusionIn the current study, radiographically evident sacroiliitis had developed in 6% of JIA patients after a median disease duration of 14.9 years. HLA–B27, absence of DPB1*02, late onset of disease, and early hip involvement were predictors of sacroiliitis.
Early and aggressive treatment of rheumatoid arthritis patients affects the association of HLA class II antigens with progression of joint damage
Authors: Lard L. R. , Boers M. , Verhoeven A. , Vos K. , Visser H. , Hazes J. M. W. , Zwinderman A. H. , Schreuder G. M. T. , Breedveld F. C. , De Vries R. R. P. , Van Der Linden S. , Zanelli E. , Huizinga T. W. J. 
Published: August 2002

AbstractObjectiveThe presence of certain HLA class II antigens is strongly associated with the progression of joint destruction in rheumatoid arthritis (RA). Such antigens may be more effective than other class II antigens in inducing the formation of autoreactive T cells after presentation of (auto)antigens. We investigated whether early and aggressive treatment with disease‐modifying antirheumatic drugs could modify this relationship.MethodsWe analyzed data from 2 studies of patients with early RA treated according to different strategies. The first study consisted of 2 cohorts, one (n = 109; median disease duration before treatment 4 months) was treated according to the pyramid strategy (initial nonsteroidal antiinflammatory drugs, followed by chloroquine [CQ] or sulfasalazine [SSZ] when necessary), and the other (n = 97; median disease duration before treatment 2 weeks) was immediately treated with CQ or SSZ. The second study comprised 155 patients (median disease duration 4 months) from the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial, in which patients were randomly assigned to combination treatment with step‐down prednisolone, methotrexate (MTX), and SSZ (n = 76) or with SSZ alone (n = 79). Prednisolone and MTX dosages were tapered and stopped after 28 and 40 weeks, respectively. The extent of joint damage was measured by the modified Sharp method.ResultsIn the pyramid treatment cohort, the median increase in Sharp score after 2 years was 12 in patients positive for the shared epitope (SE) and 1 in SE− patients. In the immediate treatment cohort, the median increase was 3 in SE+ patients and 2 in SE− patients. In the SSZ group of the COBRA study, the median increase in Sharp score after 1 year was 11 in DR4+ patients and 3 in DR4− patients. In the combination treatment group, the median increase was 4 in DR4+ patients and 2 in DR4− patients. Significance was confirmed by multiple regression using log‐transformed scores.ConclusionEarly and aggressive antirheumatic drug treatment affects the association of HLA class II alleles with progression of joint damage in RA.
Reshaping the shared epitope hypothesis: HLA‐associated risk for rheumatoid arthritis is encoded by amino acid substitutions at positions 67–74 of the HLA–DRB1 molecule
Authors: de Vries Niek , Tijssen Henk , van Riel Piet L. C. M. , van de Putte Leo B. A. 
Published: August 2002

AbstractObjectiveTo further analyze the association of HLA–DRB1 alleles with disease susceptibility in recent‐onset rheumatoid arthritis (RA).MethodsOne hundred sixty‐seven Caucasian RA patients and 166 healthy controls were typed for HLA–DRB1.ResultsThe association of susceptibility to RA with the group of alleles encoding the shared epitope susceptibility sequences (SESSs) was confirmed in recent‐onset RA. Among non‐SESS alleles, DRB1*07, *1201, *1301, and *1501 showed significant protective effects. Even after correction for the influence of SESS alleles, significant independent protective effects of DRB1 alleles were observed. Protective alleles shared a third hypervariable region motif. Independent homozygosity effects were observed both for susceptibility and for protective alleles.ConclusionNonsusceptibility alleles differ significantly with regard to RA risk. Protective alleles show clear homology at positions 67–74, often encoding isoleucine at position 67 or aspartic acid at position 70. Susceptibility and protective alleles both show homozygosity effects. Based on these results and on data reported in the literature, in order to incorporate the finding of differential risks among nonsusceptibility alleles, we propose to reshape the shared epitope hypothesis as follows: HLA‐associated risk for RA is encoded by amino acid substitutions at positions 67–74 of the HLA–DRB1 molecule.
The modulation of matrix metalloproteinase and ADAM gene expression in human chondrocytes by interleukin‐1 and oncostatin M: A time‐course study using real‐time quantitative reverse transcription–polymerase chain reaction
Authors: Koshy P. J. T. , Lundy C. J. , Rowan A. D. , Porter S. , Edwards D. R. , Hogan A. , Clark I. M. , Cawston T. E. 
Published: August 2002

AbstractObjectivePrevious studies have reported elevated levels of interleukin‐1 (IL‐1) and oncostatin M (OSM) in rheumatoid joints, as well as the synergistic degradation of human articular cartilage by this cytokine combination. The present study was undertaken to investigate the ability of IL‐1 and OSM to modulate gene expression of matrix metalloproteinase (MMP), ADAM, and ADAM‐TS (ADAM with thrombospondin motifs) family members in human chondrocytes.MethodsT/C28a4 human chondrocytes were stimulated for 2–48 hours with IL‐1 and/or OSM. Total RNA was harvested, reverse transcribed, and assessed by real‐time polymerase chain reaction for the expression of various MMP, ADAM, and ADAM‐TS messenger RNAs (mRNA). Results were normalized to 18S ribosomal RNA.ResultsIL‐1 and OSM synergized to markedly induce the expression of the collagenases MMP‐1, MMP‐8, and MMP‐13 as well as MMP‐3, an activator of proMMPs. Expression of mRNA for MMPs 1, 3, and 13 was induced early, whereas that of MMP‐8 mRNA occurred late. Gene expression of MMP‐14, an MMP that degrades collagen and activates proMMP‐13, was elevated by this combination. IL‐1 and OSM also synergized to induce gene expression of the aggrecanase ADAM‐TS4, but not ADAM‐TS5.ConclusionThese data indicate that the potent cartilage‐degrading properties of the combination of IL‐1 and OSM are potentially mediated by a synergistic induction of the aggrecan‐degrading enzyme ADAM‐TS4 and the collagen‐degrading enzymes MMP‐1, MMP‐8, MMP‐13, and MMP‐14, although differences in the magnitude of response and in the time course of induction were observed. A role for MMPs 3 and 14 in the activation of proMMPs may also be implicated.
Decreased aerobic capacity in children with juvenile dermatomyositis
Authors: Hicks Jeanne E. , Drinkard Bart , Summers Ronald M. , Rider Lisa G. 
Published: August 2002

AbstractObjectiveTo determine whether patients with juvenile dermatomyositis (DM) have limited aerobic capacity compared with healthy controls.MethodsFourteen juvenile DM patients with inactive to moderately active, stable disease (age range 7–17 years) and 14 age‐ and sex‐matched controls performed a maximal exercise test using a cycle ergometer. Oxygen uptake and power were measured at peak exercise (VO2peak and Wpeak, respectively) and at anaerobic threshold (AT and WAT). Juvenile DM disease activity and damage were also assessed.ResultsPatients with juvenile DM had significantly reduced VO2peak (19.6 ml O2/kg/minute in juvenile DM versus 31.1 ml O2/kg/minute in controls), peak heart rate (166 versus 184 beats per minute), Wpeak (1.6 versus 2.7 watts/kg), AT (11.1 versus 18.0 ml O2/kg/minute) and WAT (0.6 versus 1.4 watts/kg), compared to controls (P ≤ 0.05 for each). Aerobic exercise parameters correlated with physician global disease activity and damage, T1‐weighted magnetic resonance imaging, and Childhood Myositis Assessment Scale scores (rs = 0.58 − 0.82, P ≤ 0.05).ConclusionPatients with juvenile DM with a range of disease activity have a decreased aerobic and work capacity compared to healthy children. Aerobic exercise limitation in juvenile DM correlates best with measures of disease damage (global damage assessment, T1‐weighted magnetic resonance imaging, and disease duration). Aerobic exercise testing may be valuable in the assessment of physical endurance, and aerobic training may be indicated as part of the therapeutic regimen in myositis patients with inactive to moderately active, stable disease.
Querying and ranking XML documents
Authors: Schlieder Torsten , Meuss Holger 
Published: August 2002

AbstractXML represents both content and structure of documents. Taking advantage of the document structure promises to greatly improve the retrieval precision. In this article, we present a retrieval technique that adopts the similarity measure of the vector space model, incorporates the document structure, and supports structured queries. Our query model is based on tree matching as a simple and elegant means to formulate queries without knowing the exact structure of the data. Using this query model we propose a logical document concept by deciding on the document boundaries at query time. We combine structured queries and term‐based ranking by extending the term concept to structural terms that include substructures of queries and documents. The notions of term frequency and inverse document frequency are adapted to logical documents and structural terms. We introduce an efficient technique to calculate all necessary term frequencies and inverse document frequencies at query time. By adjusting parameters of the retrieval process we are able to model two contrary approaches: the classical vector space model, and the original tree matching approach.
Research in image indexing and retrieval as reflected in the literature
Authors: Chu Heting 
Published: August 2002

AbstractDocuments relevant to the subject of image indexing and retrieval, obtained from the SCI and SSCI databases, were examined and analyzed. The study confirms that there exist in this rapidly growing field two distinctive research groups employing the content‐based and description‐based approaches, respectively. However, research in the content‐based domain is currently dominating in the field, while the other approach has less visibility. Although researchers using the content‐based approach actively communicated with colleagues from the same group, collaboration between the different clusters of scientists should be further promoted and encouraged to advance research and development in image indexing and retrieval.
Effects of link annotations on search performance in layered and unlayered hierarchically organized information spaces
Authors: Fraser Landon , Locatis Craig 
Published: August 2002

AbstractThe effects of link annotations on user search performance in hypertext environments having deep (layered) and shallow link structures were investigated in this study. Four environments were tested—layered‐annotated, layered‐unannotated, shallow‐annotated, and shallow‐unannotated. A single document was divided into 48 sections, and layered and unlayered versions were created. Additional versions were created by adding annotations to the links in the layered and unlayered versions. Subjects were given three queries of varying difficulty and then asked to find the answers to the queries that were contained within the hypertext environment to which they were randomly assigned. Correspondence between the wording links and queries was used to define difficulty level. The results of the study confirmed previous research that shallow link structures are better than deep (layered) link structures. Annotations had virtually no effect on the search performance of the subjects. The subjects performed similarly in the annotated and unannotated environments, regardless of whether the link structures were shallow or deep. An analysis of question difficulty suggests that the wording in links has primacy over the wording in annotations in influencing user search behavior.
Distribution of ifosfamide and metabolites between plasma and erythrocytes
Authors: Kerbusch T. , Herben V.M.M. , Jeuken M‐J.J. , Ouwerkerk J. , Keizer H.J. , Beijnen J.H. 
Published: August 2002

AbstractThe distribution of ifosfamide (IF) and its metabolites 2‐dechloroethylifosfamide (2DCE), 3‐dechloroethylifosfamide (3DCE), 4‐hydroxyifosfamide (4OHIF) and ifosforamide mustard (IFM) between plasma and erythrocytes was examined in vitro and in vivo. In vitro distribution was investigated by incubating blood with various concentrations of IF and its metabolites. In vivo distribution of IF, 2DCE, 3DCE and 4OHIF was determined in 7 patients receiving 9 g/m2/72 h intravenous continuous IF infusion. In vitro distribution equilibrium between erythrocytes and plasma was obtained quickly after drug addition. Mean (±sem) in vitro and in vivo erythrocyte (e)–plasma (p) partition coefficients (Pe/p) were 0.75±0.01 and 0.81±0.03, 0.62±0.09 and 0.73±0.05, 0.76±0.10 and 0.93±0.05 and 1.38±0.04 and 0.98±0.09 for IF, 2DCE, 3DCE and 4OHIF, respectively. These ratios were independent of concentration and unaltered with time. The ratios of the area under the erythrocyte and plasma concentration‐‐time curves (AUCe/p) were 0.96±0.03, 0.87±0.07, 0.98±0.06 and 1.34±0.39, respectively. A time‐ and concentration‐dependent distribution‐‐equilibrium phenomenon was observed with the relative hydrophilic IFM. It is concluded that IF and metabolites rapidly reach distribution equilibrium between erythrocytes and plasma; the process is slower for IFM. Drug distribution to the erythrocyte fraction ranged from about 38% for 2DCE to 58% for 4OHIF, and was stable over a wide range of clinically relevant concentrations. A strong parallelism in the erythrocyte and plasma concentration profiles was observed for all compounds. Thus, pharmacokinetic assessment using only plasma sampling yields direct and accurate insights into the whole blood kinetics of IF and metabolites and may be used for pharmacokinetic–pharmacodynamic studies. Copyright © 2001 John Wiley & Sons, Ltd.
Cytological effects of 60 Hz magnetic fields on human lymphocytes in vitro: sister‐chromatid exchanges, cell kinetics and mitotic rate
Authors: Heredia–Rojas J. Antonio , Rodríguez‐De la Fuente Abraham O. , del Roble Velazco‐Campos M. , Leal‐Garza Carlos H. , Rodríguez‐Flores Laura E. , de la Fuente‐Cortez Beatriz 
Published: August 2002

AbstractIncubation for 72 h of human peripheral blood cultures in the presence of 60 Hz sinusoidal magnetic fields (MF) at magnetic flux densities of 1.0, 1.5, and 2.0 mT led to stimulation of lymphocyte proliferation but had no influence on the frequency of sister‐chromatid exchanges (SCE). The cytotoxic potential of MF combined with the mutagen Mitomycin‐C also was analyzed. An opposite effect between MF exposure and Mitomycin‐C treatment in terms of cell kinetics and mitotic rate was found, whereas no variation in SCE frequency was observed for this coexposure condition. Bioelectromagnetics 22:145–149, 2001. © 2001 Wiley‐Liss, Inc.
Long‐term effects of 60‐Hz electric vs. magnetic fields on IL‐1 and IL‐2 activity in sheep
Authors: Hefeneider Steven H. , McCoy Sharon L. , Hausman Frances A. , Christensen Heidi L. , Takahashi Diana , Perrin Nancy , Bracken T. Dan , Shin K.Y. , Hall Arthur S. 
Published: August 2002

AbstractThis study was designed to assess the effect of exposure to long‐term extremely low‐frequency electric and magnetic fields (ELF–EMF) from a 500 kV transmission line on IL‐1 and IL‐2 activity in sheep. The primary hypothesis was that the reduction in IL‐1 activity observed in our two previous short‐term studies (10 months) was due to EMF exposure from this transmission line. To repeat and expand these studies and to characterize the components of EMF responsible for the previously observed reduction in IL‐1 activity, the current experiment examined not only the effect of exposure to electric and magnetic fields, but also the magnetic field component alone. In the current study, IL‐2 was examined to characterize the effects of EMF exposure on an indicator of T cell responses. 45 Suffolk ewe lambs were randomized into three groups of 15 animals each. One group of animals was placed in the EMF pen, located directly beneath the transmission line. A second group was placed in the shielded MF (magnetic field only) pen, also directly beneath the transmission line. The third group of animals was placed in the control pen located several hundred meters away from the transmission line. During the 27 month exposure period, blood samples were taken from all animals monthly. When the data were analyzed collectively over time, no significant differences between the groups were found for IL‐1 or IL‐2 activity. In previous studies ewe lambs of 8–10 weeks of age were used as the study animals and significant differences in IL‐1 activity were observed after exposure of these animals to EMF at mean magnetic fields of 3.5–3.8 μT (35–38 mG) and mean electric fields of 5.2–5.8 kV/m. At the start of the current study EMF levels were reduced as compared to previous studies. One interpretation of the current data is that magnetic field strength and age of the animals may be important variables in determining whether EMF exposure will affect IL‐1 activity. Bioelectromagnetics 22:170–177, 2001. © 2001 Wiley‐Liss, Inc.
Alternative magnetic field exposure metrics: Relationship to TWA, appliance use, and demographic characteristics of children in a leukemia survival study
Authors: Foliart Donna E. , Iriye Richard N. , Tarr Kathleen J. , Silva J. Michael , Kavet Rob , Ebi Kristie L. 
Published: August 2002

AbstractThe ongoing Childhood Leukemia Survival Study is examining the possible association between magnetic field exposure and survival of children with newly diagnosed acute lymphocytic leukemia (ALL). We report the results of the first year 24 h personal magnetic field monitoring for 356 US and Canadian children by time weighted average TWA and alternative exposure metrics. The mean TWA of 0.12 μT was similar to earlier personal exposure studies involving children. A high correlation was found between 24 h TWA and alternative metrics: 12 h day TWA, 12 night TWA, geometric mean, 95th percentile value, percentage time over 0.2 and 0.3 μT, and an estimate of field stability (Constant Field Metric). Two measures of field intermittency, rate of change metric (RCM) and standardized rate of change metric (RCMS), were not highly correlated with TWA. The strongest predictor of TWA was location of residence, with highest TWAs associated with urban areas. Residence in an apartment, lower paternal educational level, and residential mobility were also associated with higher TWAs. There were no significant differences in the appliance use patterns of children with higher TWA values. Children with the highest field intermittency (high RCM) were more likely to sit within 3 feet of a video game attached to the TV. Our results suggest that 24 h TWA is a representative metric for certain patterns of exposure, but is not highly correlated with two metrics that estimate field intermittency. Bioelectromagnetics 22:574–580, 2001. © 2001 Wiley‐Liss, Inc.
Leptin signaling pathways in the central nervous system: interactions between neuropeptide Y and melanocortins
Authors: Rahmouni Kamal , Haynes William G. 
Published: August 2002

AbstractNo other hormone has drawn more attention than leptin in recent studies on the control of appetite, body weight and obesity. This hormone is produced by adipose tissue and enters the brain via a saturable specific transport mechanism. Leptin acts in the hypothalamus to modulate food intake and heat production as well as several other neuroendocrine pathways. The mechanisms through which leptin exerts its central nervous effects are now better understood. Proopiomelanocortin‐ and neuropeptide Y‐containing neurons in the hypothalamus have emerged as potent candidate mediators of leptin action. These two neuropeptides have been shown to exert opposing effects using different pathways. Recently, Cowley et al. (2001) described a new circuit in the regulation of neuronal activity by leptin with an interaction between these two pathways. These data add complexity to the mechanisms by which leptin achieves its effects in the central nervous system, but they also offer potential mechanisms to explain the phenomenon of leptin resistance observed in obesity. BioEssays 23:1095–1099, 2001. © 2001 John Wiley & Sons, Inc.
Plant chromatin: Development and gene control*
Authors: Li Guofu , Hall Timothy C. , Holmes‐Davis Rachel 
Published: August 2002

AbstractIt is increasingly clear that chromatin is not just a device for packing DNA within the nucleus but also a dynamic material that changes as cellular environments alter. The precise control of chromatin modification in response to developmental and environmental cues determines the correct spatial and temporal expression of genes. Here, we review exciting discoveries that reveal chromatin participation in many facets of plant development. These include: chromatin modification from embryonic and meristematic development to flowering and seed formation, the involvement of DNA methylation and chromatin in controlling invasive DNA and in maintenance of epigenetic states, and the function of chromatin modifying and remodeling complexes such as SWI/SNF and histone acetylases and deacetylases in gene control. Given the role chromatin structure plays in every facet of plant development, chromatin research will undoubtedly be integral in both basic and applied plant biology. BioEssays 24:234–243, 2002. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/bies.10055