bluuebunny/crossref_metadata_2025 huggingface dataset:
Different patterns of associations with anti–citrullinated protein antibody–positive and anti–citrullinated protein antibody–negative rheumatoid arthritis in the extended major histocompatibility complex region
Authors: Ding Bo , Padyukov Leonid , Lundström Emeli , Seielstad Mark , Plenge Robert M. , Oksenberg Jorge R. , Gregersen Peter K. , Alfredsson Lars , Klareskog Lars
Published: December 2008

Objective

To identify additional variants in the major histocompatibility complex (MHC) region that independently contribute to risk in 2 disease subsets of rheumatoid arthritis (RA) defined according to the presence or absence of antibodies to citrullinated protein antigens (ACPAs).

Methods

In a multistep analytical strategy using unmatched as well as matched analyses to adjust for HLA–DRB1 genotype, we analyzed 2,221 single‐nucleotide polymorphisms (SNPs) spanning 10.7 Mb, from 6p22.2 to 6p21.31, across the MHC. For ACPA‐positive RA, we analyzed samples from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) and the North American Rheumatoid Arthritis Consortium (NARAC) studies (totaling 1,255 cases and 1,719 controls). For ACPA‐negative RA, we used samples from the EIRA study (640 cases and 670 controls). Plink and SAS statistical packages were used to conduct all statistical analyses.

Results

A total of 299 SNPs reached locus‐wide significance (P < 2.3 × 10−5) for ACPA‐positive RA, whereas surprisingly, no SNPs reached this significance for ACPA‐negative RA. For ACPA‐positive RA, we adjusted for known DRB1 risk alleles and identified additional independent associations with SNPs near HLA–DPB1 (rs3117213; odds ratio 1.42 [95% confidence interval 1.17–1.73], Pcombined = 0.0003 for the strongest association).

Conclusion

There are distinct genetic patterns of MHC associations in the 2 disease subsets of RA defined according to ACPA status. HLA–DPB1 is an independent risk locus for ACPA‐positive RA. We did not identify any associations with SNPs within the MHC for ACPA‐negative RA.
CXCR3+CD4+ T cells are enriched in inflamed kidneys and urine and provide a new biomarker for acute nephritis flares in systemic lupus erythematosus patients
Authors: Enghard P. , Humrich J. Y. , Rudolph B. , Rosenberger S. , Biesen R. , Kuhn A. , Manz R. , Hiepe F. , Radbruch A. , Burmester G.‐R. , Riemekasten G.
Published: December 2008

Objective

The high frequency of CD4+ T cells in interstitial infiltrates of patients with lupus nephritis suggests a contribution of these cells to local pathogenesis. The aim of this study was to examine the role of CXCR3 and the chemokine CXCL10 in recruiting these cells into the kidney and to determine whether the infiltrating T cells could be monitored in the urine to provide a reliable biomarker for acute lupus nephritis.

Methods

The frequencies of CD3+ T cells, CXCR3+ cells, and CXCL10+ cells were determined by immunohistochemical and immunofluorescence analyses of kidney sections from 18 patients with lupus nephritis. The frequency of CXCR3+CD4+ T cells was determined by flow cytometry of peripheral blood and urine from 38 patients with systemic lupus erythematosus (SLE), and the values were compared with disease activity as determined by the Systemic Lupus Erythematosus Disease Activity Index.

Results

In renal biopsy tissues from patients with lupus nephritis, a mean of 63% of the infiltrating cells expressed CXCR3, ∼60% of them were T cells, and the CXCR3+ cells colocalized with CXCL10‐producing cells. In biopsy tissues from SLE patients with acute nephritis, ∼50% of the urinary CD4+ T cells were CXCR3+, as compared with 22% in the peripheral blood, and the frequency of urinary CXCR3+CD4+ T cells correlated with disease activity. Moreover, the number of urinary CD4+ T cells reflected nephritis activity, and elevation above 800 CD4+ T cells per 100 ml of urine sharply delineated active from inactive nephritis.

Conclusion

CXCR3+ T cells are recruited into the inflamed kidneys, are enriched in the urine, and are a valuable marker of nephritis activity in SLE. They also present a potential target for future therapies.
Tolerization with Hsp65 induces protection against adjuvant‐induced arthritis by modulating the antigen‐directed interferon‐γ, interleukin‐17, and antibody responses
Authors: Satpute Shailesh R. , Rajaiah Rajesh , Polumuri Swamy K. , Moudgil Kamal D.
Published: December 2008

Objective

Pretreatment of Lewis rats with soluble mycobacterial Hsp65 affords protection against subsequent adjuvant‐induced arthritis (AIA). This study was aimed at unraveling the mechanisms underlying mycobacterial Hsp65–induced protection against arthritis, using contemporary parameters of immunity.

Methods

Lewis rats were given 3 intraperitoneal injections of mycobacterial Hsp65 in solution prior to the initiation of AIA with heat‐killed Mycobacterium tuberculosis. Thereafter, mycobacterial Hsp65–specific T cell proliferative, cytokine, and antibody responses were tested in tolerized rats. The roles of anergy and the indoleamine 2,3 dioxygenase (IDO)–tryptophan pathway in tolerance induction were assessed, and the frequency and suppressive function of CD4+FoxP3+ Treg cells were monitored. Also tested was the effect of mycobacterial Hsp65 tolerization on T cell responses to AIA‐related mycobacterial Hsp70, mycobacterial Hsp10, and rat Hsp65.

Results

The AIA‐protective effect of mycobacterial Hsp65–induced tolerance was associated with a significantly reduced T cell proliferative response to mycobacterial Hsp65, which was reversed by interleukin‐2 (IL‐2), indicating anergy induction. The production of interferon‐γ (but not IL‐4/IL‐10) was increased, with concurrent down‐regulation of IL‐17 expression by mycobacterial Hsp65–primed T cells. Neither the frequency nor the suppressive activity of CD4+FoxP3+ T cells changed following tolerization, but the serum level of anti–mycobacterial Hsp65 antibodies was increased. However, no evidence was observed for a role of IDO or cross‐tolerance to mycobacterial Hsp70, mycobacterial Hsp10, or rat Hsp65.

Conclusion

Tolerization with soluble mycobacterial Hsp65 leads to suppression of IL‐17, anergy induction, and enhanced production of anti–mycobacterial Hsp65 antibodies, which play a role in protection against AIA. These results are relevant to the development of effective immunotherapeutic approaches for autoimmune arthritis.
Sodium oxybate relieves pain and improves function in fibromyalgia syndrome: A randomized, double‐blind, placebo‐controlled, multicenter clinical trial
Authors: Russell I. Jon , Perkins A. Thomas , Michalek Joel E. ,   Oxybate SXB‐26 Fibromyalgia Syndrome Study Group
Published: December 2008

Objective

To evaluate the safety and efficacy of sodium oxybate for management of the symptoms of fibromyalgia syndrome (FMS).

Methods

Patients with FMS (according to the American College of Rheumatology 1990 criteria) were randomized, after discontinuing their prestudy medications for FMS, to receive 4.5 gm or 6 gm of sodium oxybate or matching placebo once per night for 8 weeks. The primary outcome variable (POV) was a composite score for changes from baseline in 3 coprimary self‐report measures: patient's pain rating (in daily electronic diaries) on a visual analog scale (PVAS), the Fibromyalgia Impact Questionnaire (FIQ) score, and the Patient Global Impression of Change (PGI‐C). A beneficial response rate for the POV composite score was defined as ≥20% improvement in the PVAS and FIQ scores plus a rating of “much better” or “very much better” on the PGI‐C. Secondary measures included subjective sleep outcomes (on the Jenkins Scale for Sleep) and quality‐of‐life measures. The analyses were based on an intent‐to‐treat (ITT) population.

Results

The ITT population included 188 patients with FMS, 78% of whom completed the trial. Significant benefit was observed with both dosages of sodium oxybate, according to changes in the POV and subjective sleep quality. Improvements in the PVAS score were significantly correlated with sleep outcomes. Sodium oxybate was well tolerated overall; dose‐related nausea (≤28% of patients) and dizziness (≤18% of patients) tended to resolve with continued therapy.

Conclusion

Sodium oxybate therapy was well tolerated and significantly improved the symptoms of FMS. Further study of sodium oxybate as a novel therapeutic option for FMS is warranted.
Modulation of lubricin biosynthesis and tissue surface properties following cartilage mechanical injury
Authors: Jones Aled R. C. , Chen Shuodan , Chai Diana H. , Stevens Anna L. , Gleghorn Jason P. , Bonassar Lawrence J. , Grodzinsky Alan J. , Flannery Carl R.
Published: December 2008

Objective

To evaluate the effects of injurious compression on the biosynthesis of lubricin at different depths within articular cartilage and to examine alterations in structure and function of the articular surface following mechanical injury.

Methods

Bovine cartilage explants were subdivided into level 1, with intact articular surface, and level 2, containing middle and deep zone cartilage. Following mechanical injury, lubricin messenger RNA (mRNA) levels were monitored by quantitative reverse transcriptase–polymerase chain reaction, and soluble or cartilage‐associated lubricin protein was analyzed by Western blotting and immunohistochemistry. Cartilage morphology was assessed by histologic staining, and tissue functionality was assessed by friction testing.

Results

Two days after injury, lubricin mRNA expression was up‐regulated ∼3‐fold for level 1 explants and was down‐regulated for level 2 explants. Lubricin expression in level 1 cartilage returned to control levels after 6 days in culture. Similarly, lubricin protein synthesis and secretion increased in response to injury for level 1 explants and decreased for level 2 cartilage. Histologic staining revealed changes in the articular surface of level 1 explants following injury, with respect to glycosaminoglycan and collagen content. Injured level 1 explants displayed an increased coefficient of friction relative to controls.

Conclusion

Our findings indicate that increased lubricin biosynthesis appears to be an early transient response of surface‐layer cartilage to injurious compression. However, distinct morphologic changes occur with injury that appear to compromise the frictional properties of the tissue.
Differential expression of αB‐crystallin and evidence of its role as a mediator of matrix gene expression in osteoarthritis
Authors: Lambrecht Stijn , Verbruggen Gust , Elewaut Dirk , Deforce Dieter
Published: December 2008

Objective

Alpha B–crystallin belongs to the family of small heat‐shock proteins (HSPs). The role of this protein family in chondrocytes is not well understood. The present study was undertaken to investigate expression levels of αB‐crystallin in chondrocytes isolated from healthy subjects and patients with osteoarthritis (OA), and to explore the functional role of this potentially interesting protein in chondrocyte metabolism.

Methods

Western blot and real‐time reverse transcriptase–polymerase chain reaction (RT‐PCR) analyses were performed to determine expression levels of αB‐crystallin in healthy and OA chondrocytes cultured in alginate beads. RNA interference–mediated gene knockdown was used to explore the role of this small HSP in chondrocyte biology, by transfecting low concentrations of small interfering RNA (siRNA) in cultured chondrocytes.

Results

We initially identified αB‐crystallin as a small HSP that was differentially expressed between healthy and OA‐affected chondrocytes. The decreased abundance of this protein in OA chondrocytes was confirmed by Western blotting. Moreover, real‐time RT‐PCR confirmed the differential expression between chondrocytes isolated from visibly intact and visibly damaged zones of OA cartilage. The proinflammatory cytokines interleukin‐1β and tumor necrosis factor α both down‐regulated αB‐crystallin expression. Transfection of low concentrations of siRNA in cultured chondrocytes resulted in efficient knockdown of αB‐crystallin gene expression. This was accompanied by altered expression of the chondrocyte‐specific bone morphogenetic protein 2, aggrecan, and type II collagen genes.

Conclusion

The present findings identify the small HSP αB‐crystallin as a novel mediator of chondrocyte matrix gene expression that may contribute to altered chondrocyte metabolism during the development of OA.
Identification of relevant concepts of functioning in daily life in people with systemic lupus erythematosus: A patient Delphi exercise
Authors: Bauernfeind Bettina , Aringer Martin , Prodinger Birgit , Kirchberger Inge , Machold Klaus , Smolen Josef , Stamm Tanja
Published: December 2008

Objective

To identify the most important and relevant concepts of daily functioning from the perspective of patients with systemic lupus erythematosus (SLE).

Methods

We conducted a consensus‐building, 3‐round, electronic mail survey with SLE patients using the Delphi technique. The Delphi technique is a structured communication process with 4 key characteristics: anonymity, iteration with controlled feedback, statistical group response, and informed input. The concepts contained in the answers of the patients were extracted and linked to the International Classification of Functioning, Disability and Health (ICF).

Results

Of the total 225 participants, 194 (86.2%) completed the questionnaires from all 3 Delphi rounds. In total, after the third Delphi round, 307 concepts were identified. Ninety concepts (55 in the domain body functions and structures, 16 in activities and participation, and 19 in environmental factors) were considered relevant by at least 50% of the participants in the third round and linked to the ICF. Twelve concepts were considered important by at least 75% of the participants.

Conclusion

The high number of concepts resulting from this large‐scale patient Delphi approach underlines the great variety of SLE patients' problems in daily functioning. The results of this patient Delphi project supplement the findings of our focus‐group study in establishing a comprehensive overview of the patient perspective in SLE.
Effects of cryotherapy on arthrogenic muscle inhibition using an experimental model of knee swelling
Authors: Rice David , McNair Peter J. , Dalbeth Nicola
Published: December 2008

Objective

Arthrogenic muscle inhibition (AMI) contributes to quadriceps weakness and atrophy in knee arthritis and following joint injury. This laboratory‐based study examined the efficacy of cryotherapy in reducing quadriceps AMI caused by intraarticular swelling.

Methods

Sixteen subjects without knee pathology participated, and were randomly assigned to a cryotherapy (n = 8) or control (n = 8) group. Surface electromyography (EMG) from vastus medialis and quadriceps torque measurements were recorded during maximum effort isometric contractions. All subjects then received an experimental joint infusion, whereby dextrose saline was injected into the knee to an intraarticular pressure of 50 mm Hg. EMG and torque measurements were repeated. Thereafter, the cryotherapy group had ice applied to the knee for 20 minutes while the control group did not receive an intervention. EMG and torque measurements were again collected. Quadriceps peak torque, muscle fiber conduction velocity (MFCV), and the root mean square (RMS) of EMG signals from vastus medialis were analyzed.

Results

Quadriceps peak torque, MFCV, and RMS decreased significantly following joint infusion (P ≤ 0.001). Cryotherapy led to a significant increase in quadriceps torque and MFCV compared with controls (P < 0.05). The difference in RMS did not reach statistical significance (P = 0.13).

Conclusion

The study demonstrated that cryotherapy is effective in reducing AMI induced by swelling. Cryotherapy may allow earlier and more effective quadriceps strengthening to occur in patients with knee joint pathology.
Association between the IRF5 rs2004640 functional polymorphism and systemic sclerosis: A new perspective for pulmonary fibrosis
Authors: Dieudé P. , Guedj M. , Wipff J. , Avouac J. , Fajardy I. , Diot E. , Granel B. , Sibilia J. , Cabane J. , Mouthon L. , Cracowski J. L. , Carpentier P. H. , Hachulla E. , Meyer O. , Kahan A. , Boileau C. , Allanore Y.
Published: December 2008

Objective

There is now growing evidence that connective tissue diseases, including systemic sclerosis (SSc), share a common genetic background. Microarray studies support a pivotal role of type I interferon (IFN) in the pathophysiology of connective tissue diseases. Interferon regulatory factors coordinate the expression of type I IFNs, and the IRF5 gene has been identified as a susceptibility gene of systemic lupus and Sjögren's syndrome. The aim of this study was to determine whether the IRF5 rs2004640 single‐nucleotide polymorphism is associated with SSc.

Methods

The IRF5 rs2004640 (GT) functional polymorphism was genotyped in 1,641 subjects of French European Caucasian origin: a discovery set comprising 427 patients with SSc and 380 control subjects and a replication set comprising 454 patients with SSc and 380 control subjects.

Results

In both the discovery set and the replication set, the TT genotype was significantly more common in patients with SSc than in control subjects, with an odds ratio (OR) for the combined populations of 1.58 (95% confidence interval [95% CI] 1.18–2.11 [P for trend 0.002]). Analyses of the whole SSc population showed a significant association between homozygosity for the T allele and the presence of antinuclear antibodies (corrected P [Pcorr] = 0.04, OR 1.59, 95% CI 1.16–2.17) and fibrosing alveolitis (Pcorr = 0.001, OR 2.07, 95% CI 1.38–3.11). In a multivariate analysis model including the diffuse cutaneous subtype of SSc and positivity for anti–topoisomerase I antibodies, the IRF5 rs2004640 TT genotype remained associated with fibrosing alveolitis (P = 0.029, OR 1.92, 95% CI 1.07–3.44).

Conclusion

The IRF5 rs2004640 GT substitution is associated with susceptibility to SSc. These data provide new insight into the pathogenesis of SSc, including clues to the mechanisms leading to fibrosing alveolitis.
Resident macrophages initiating and driving inflammation in a monosodium urate monohydrate crystal–induced murine peritoneal model of acute gout
Authors: Martin William John , Walton Michaela , Harper Jacquie
Published: December 2008

Objective

To determine whether infiltrating monocytes, neutrophils, or resident macrophages contribute to the early inflammatory response to monosodium urate monohydrate (MSU) crystals in vivo.

Methods

MSU crystal–induced inflammation was monitored using a peritoneal model of acute gout. The production of proinflammatory cytokines (interleukin‐1β [IL‐1β], tumor necrosis factor α [TNFα], IL‐6) by resident macrophages, infiltrating monocytes, and neutrophils during the onset of gout was determined by flow cytometry. Infiltrating and resident peritoneal cells were cultured with MSU crystals ex vivo, and proinflammatory cytokine production was determined by multiplex cytokine array. Activated macrophages on the visceral epithelial lining of the peritoneum were identified by immunofluorescence histochemistry. The inflammatory immune response to MSU crystals was then compared with the inflammatory response in mice depleted of resident macrophages by pretreatment with clodronate liposomes.

Results

The production of cytokines in vivo preceded the influx of Gr‐1intermediate7/4+ monocytes. Monocytes and neutrophils recruited during the inflammatory phase of the response to MSU crystals failed to produce proinflammatory cytokines either in vivo, or ex vivo following restimulation with MSU crystals. Stimulation of the naive peritoneal resident cell population with MSU crystals ex vivo resulted in positive staining of resident macrophages for the proinflammatory cytokines IL‐1β, TNFα, and IL‐6. Depletion of the resident macrophage population resulted in a significant decrease in both MSU crystal–induced neutrophil infiltration and proinflammatory cytokine production in vivo despite the presence of infiltrating monocytes.

Conclusion

These data indicate that resident macrophages, rather than infiltrating monocytes or neutrophils, are important for initiating and driving the early proinflammatory phase of acute gout.
Association of the IL2RA/CD25 gene with juvenile idiopathic arthritis
Authors: Hinks Anne , Ke Xiayi , Barton Anne , Eyre Steve , Bowes John , Worthington Jane ,   UK Rheumatoid Arthritis Genetics Consortium,   British Society of Paediatric and Adolescent Rheumatology Study Group, Thompson Susan D. , Langefeld Carl D. , Glass David N. , Thomson Wendy
Published: December 2008

Objective

IL2RA/CD25, the gene for interleukin‐2 receptor α, is emerging as a general susceptibility gene for autoimmune diseases because of its role in the development and function of regulatory T cells and the association of single‐nucleotide polymorphisms (SNPs) within this gene with type 1 diabetes mellitus (DM), Graves' disease, rheumatoid arthritis (RA), and multiple sclerosis (MS). The aim of this study was to determine whether SNPs within the IL2RA/CD25 gene are associated with juvenile idiopathic arthritis (JIA).

Methods

Three SNPs within the IL2RA/CD25 gene, that previously showed evidence of an association with either RA, MS, or type 1 DM, were selected for genotyping in UK JIA cases (n = 654) and controls (n = 3,849). Data for 1 SNP (rs2104286) were also available from North American JIA cases (n = 747) and controls (n = 1,161). Association analyses were performed using Plink software. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

Results

SNP rs2104286 within the IL2RA/CD25 gene was significantly associated with UK JIA cases (OR for the allele 0.76 [95% CI 0.66–0.88], P for trend = 0.0002). A second SNP (rs41295061) also showed modest evidence for association with JIA (OR 0.80 [95% CI 0.63–1.0], P = 0.05). Association with rs2104286 was convincingly replicated in the North American JIA cohort (OR 0.84 [95% CI 0.65–0.99], P for trend = 0.05). Meta‐analysis of the 2 cohorts yielded highly significant evidence of association with JIA (OR 0.76 [95% CI 0.62–0.88], P = 4.9 × 10−5).

Conclusion

These results provide strong evidence that the IL2RA/CD25 gene represents a JIA susceptibility locus. Further investigation of the gene using both genetic and functional approaches is now required.
Folate receptor β as a potential delivery route for novel folate antagonists to macrophages in the synovial tissue of rheumatoid arthritis patients
Authors: Van Der Heijden Joost W. , Oerlemans Ruud , Dijkmans Ben A. C. , Qi Huiling , Laken Conny J. Van Der , Lems Willem F. , Jackman Ann L. , Kraan Maarten C. , Tak Paul P. , Ratnam Manohar , Jansen Gerrit
Published: December 2008

Objective

To determine the expression of folate receptor β (FRβ) in synovial biopsy tissues and peripheral blood lymphocytes from rheumatoid arthritis (RA) patients and to identify novel folate antagonists that are more selective in the targeting and internalization of FRβ than methotrexate (MTX).

Methods

Immunohistochemistry and computer‐assisted digital imaging analyses were used for the detection of FRβ protein expression on immunocompetent cells in synovial biopsy samples from RA patients with active disease and in noninflammatory control synovial tissues. FRβ messenger RNA (mRNA) levels were determined by reverse transcription–polymerase chain reaction analysis. Binding affinities of FRβ for folate antagonists were assessed by competition experiments for3H‐folic acid binding on FRβ‐transfected cells. Efficacy of FRβ‐mediated internalization of folate antagonists was evaluated by assessment of antiproliferative effects against FRβ‐transfected cells.

Results

Immunohistochemical staining of RA synovial tissue showed high expression of FRβ on macrophages in the intimal lining layer and synovial sublining, whereas no staining was observed in T cell areas or in control synovial tissue. Consistently, FRβ mRNA levels were highest in synovial tissue extracts and RA monocyte‐derived macrophages, but low in peripheral blood T cells and monocytes. Screening of 10 new‐generation folate antagonists revealed 4 compounds for which FRβ had a high binding affinity (20–77‐fold higher than for MTX). One of these, the thymidylate synthase inhibitor BCG 945, displayed selective targeting against FRβ‐transfected cells.

Conclusion

Abundant FRβ expression on activated macrophages in synovial tissue from RA patients deserves further exploration for selective therapeutic interventions with high‐affinity–binding folate antagonists, of which BCG 945 may be a prototypical representative.
Risk factors for thrombosis and primary thrombosis prevention in patients with systemic lupus erythematosus with or without antiphospholipid antibodies
Authors: Tektonidou Maria G. , Laskari Katerina , Panagiotakos Demosthenes B. , Moutsopoulos Haralampos M.
Published: December 2008

Objective

Antiphospholipid antibodies (aPL), namely anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC), have been associated with an increased risk of thrombosis in systemic lupus erythematosus (SLE). We examined additional thrombosis risk factors (aPL profile, SLE‐related, and traditional risk factors) and the primary thrombosis prevention in SLE patients with and without aPL.

Methods

All SLE patients with positive aPL but without previous thrombotic manifestations who were regularly followed up at our department (n = 144) and 144 age‐ and sex‐matched SLE patients with negative aPL were included in this study. The median followup times were 104 and 112 months, respectively. The demographic, clinical, laboratory, and treatment characteristics and the traditional thrombosis risk factors were recorded.

Results

The thrombosis rate was 29 per 144 aPL‐positive patients (20.1%) and 11 per 144 aPL‐negative patients (7.6%; P = 0.003). In multiadjusted analysis, significant predictors of thrombosis were male sex (hazard ratio [HR] 6.25, P < 0.01), LAC (HR 3.48, P = 0.04), and constantly positive aCL (HR 5.87, P = 0.01) for aPL‐positive patients, while male sex (HR 7.14, P = 0.03) and hypertension were predictors for aPL‐negative patients (HR 6.49, P = 0.03). Additionally, the duration of low‐dose aspirin treatment played a protective role against thrombosis in aPL‐positive patients (HR per month 0.98, P = 0.05), as did the duration of hydroxychloroquine in both aPL‐positive (HR per month 0.99, P = 0.05) and aPL‐negative patients (HR per month 0.98, P = 0.04).

Conclusion

Independent predictors of thrombosis for aPL‐positive patients were male sex, LAC, and constantly positive aCL, and for aPL‐negative patients were male sex and hypertension. The duration of low‐dose aspirin use played a protective role against thrombosis in aPL‐positive patients as did the duration of hydroxychloroquine in both groups.
A clustering‐based semi‐automated technique to build cultural ontologies
Authors: Srinivasan Ramesh , Pepe Alberto , Rodriguez Marko A.
Published: December 2008

This article presents and validates a clustering‐based method for creating cultural ontologies for community‐oriented information systems. The introduced semiautomated approach merges distributed annotation techniques, or subjective assessments of similarities between cultural categories, with established clustering methods to produce “cognate” ontologies. This approach is validated against a locally authentic ethnographic method, involving direct work with communities for the design of “fluid” ontologies. The evaluation is conducted with of a set of Native American communities located in San Diego County (CA, US). The principal aim of this research is to discover whether distributing the annotation process among isolated respondents would enable ontology hierarchies to be created that are similar to those that are crafted according to collaborative ethnographic processes, found to be effective in generating continuous usage across several studies. Our findings suggest that the proposed semiautomated solution best optimizes among issues of interoperability and scalability, deemphasized in the fluid ontology approach, and sustainable usage.
Imidazole‐Annulated Tetrathiafulvalenes Exhibiting pH‐Tuneable Intramolecular Charge Transfer and Redox Properties
Authors: Wu Jincai , Dupont Nathalie , Liu Shi‐Xia , Neels Antonia , Hauser Andreas , Decurtins Silvio
Published: December 2008

CT or not CT: Three imidazole‐annulated TTF derivatives 1–3 have been prepared and fully characterized. The influence of the TTF unit on the pKa values of the acceptor units as determined by photometric titration has been discussed. The results reported here are part of an initial exploratory study to generate a range of well‐defined coordination networks.

magnified image

In order to study the electronic interactions in donor–acceptor ensembles as a function of pH, an efficient synthetic route to three imidazole‐annulated tetrathiafulvalene (TTF) derivatives 1–3 is reported. Their electronic absorption spectra, in view of photoinduced intramolecular charge transfer, and their electrochemical behavior were investigated, and pKa values for the two protonation processes on the acceptor unit were determined in organic solvents by photometric titration. The influence of the TTF moiety on these values is discussed.
Examination of association to autism of common genetic variationin genes related to dopamine
Authors: Anderson B.M. , Schnetz‐Boutaud N. , Bartlett J. , Wright H.H. , Abramson R.K. , Cuccaro M.L. , Gilbert J.R. , Pericak‐Vance M.A. , Haines J.L.
Published: December 2008

Autism is a severe neurodevelopmental disorder characterized by a triad of complications. Autistic individuals display significant disturbances in language and reciprocal social interactions, combined with repetitive and stereotypic behaviors. Prevalence studies suggest that autism is more common than originally believed, with recent estimates citing a rate of one in 150. Although multiple genetic linkage and association studies have yielded multiple suggestive genes or chromosomal regions, a specific risk locus has yet to be identified and widely confirmed. Because many etiologies have been suggested for this complex syndrome, we hypothesize that one of the difficulties in identifying autism genes is that multiple genetic variants may be required to significantly increase the risk of developing autism. Thus, we took the alternative approach of examining 14 prominent dopamine pathway candidate genes for detailed study by genotyping 28 single nucleotide polymorphisms. Although we did observe a nominally significant association for rs2239535 (P=0.008) on chromosome 20, single‐locus analysis did not reveal any results as significant after correction for multiple comparisons. No significant interaction was identified when Multifactor Dimensionality Reduction was employed to test specifically for multilocus effects. Although genome‐wide linkage scans in autism have provided support for linkage to various loci along the dopamine pathway, our study does not provide strong evidence of linkage or association to any specific gene or combination of genes within the pathway. These results demonstrate that common genetic variation within the tested genes located within this pathway at most play a minor to moderate role in overall autism pathogenesis.
Specific impairment of face‐processing abilities in children with autism spectrum disorder using the Let's Face It! skills battery
Authors: Wolf Julie M. , Tanaka James W. , Klaiman Cheryl , Cockburn Jeff , Herlihy Lauren , Brown Carla , South Mikle , McPartland James , Kaiser Martha D. , Phillips Rebecca , Schultz Robert T.
Published: December 2008

Although it has been well established that individuals with autism exhibit difficulties in their face recognition abilities, it has been debated whether this deficit reflects a category‐specific impairment of faces or a general perceptual bias toward the local‐level information in a stimulus. In this study, the Let's Face It! Skills Battery [Tanaka & Schultz, 2008] of developmental face‐ and object‐processing measures was administered to a large sample of children diagnosed with autism spectrum disorder (ASD) and typically developing children. The main finding was that when matched for age and IQ, individuals with ASD were selectively impaired in their ability to recognize faces across changes in orientation, expression and featural information. In a face discrimination task, ASD participants showed a preserved ability to discriminate featural and configural information in the mouth region of a face, but were compromised in their ability to discriminate featural and configural information in the eyes. On object‐processing tasks, ASD participants demonstrated a normal ability to recognize automobiles across changes in orientation and a superior ability to discriminate featural and configural information in houses. These findings indicate that the face‐processing deficits in ASD are not due to a local‐processing bias, but reflect a category‐specific impairment of faces characterized by a failure to form view‐invariant face representations and discriminate information in the eye region of the face.
NMR evidence of charge‐dependent interaction between various PND V3 and CCR5 N‐terminal peptides
Authors: Galanakis Petros A. , Kandias Nikolaos G. , Rizos Apostolos K. , Morikis Dimitrios , Krambovitis Elias , Spyroulias Georgios A.
Published: December 2008

The third variable (V3) loop is an important region of glycoprotein 120 (gp120) for many biological processes, as it contains the highly conserved GPGR sequence and it represents the binding site for human immunodeficiency virus 1 (HIV‐1) antibodies and for CCR5 and CXCR4 host cell coreceptors. The interaction of the principal neutralizing determinant (PND) V3 with the chemokine receptor CCR5 N‐terminal region has been reported to be crucial for HIV‐1 infection. The goal of this study is to characterize the solution structures of three HIV‐1 gp120 V3 subtype B peptides and their interaction with a nonsulfated N‐terminal CCR5 peptide. NMR titration experiments revealed that the CCR5Nt‐PND V3 interaction is dependent on the number of the positively charged V3 residues, which is in agreement with the observation that increase in positive charge in the V3 sequence correlates with the augmentation of the interaction. As expected for free peptides in solution, the peptides representing the PND V3 region of gp120 exhibit conformational flexibility, but they also exhibit a large number of NOEs which allowed convergence to a dominant conformation. The PND V3 peptides retain the U‐turn conformation observed in the crystal structures of gp120 complexes independently of CCR5 presence. The interaction of different regions of the CCR5Nt peptide is gradually increasing proportionally to the positive charge increase in the V3 peptides. The data demonstrate that the PND V3 and CCR5Nt peptide sequences have propensities for interaction even in the absence of sulfated tyrosines and that their binding and selectivity is determined by simple electrostatic attraction mechanisms. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 94–109, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Evaluation of binding selectivities and affinities of platinum‐based quadruplex interactive complexes by electrospray ionization mass spectrometry
Authors: Pierce Sarah E. , Kieltyka Roxanne , Sleiman Hanadi F. , Brodbelt Jennifer S.
Published: December 2008

The quadruplex binding affinities and selectivities of two large π‐surface PtII phenanthroimidazole complexes, as well as a smaller π‐surface platinum bipyridine complex and a larger RuII complex, were evaluated by electrospray ionization mass spectrometry. Circular dichroism (CD) spectroscopy was used to determine the structures of various quadruplexes and to study the thermal denaturation of the quadruplexes in the absence and presence of the metal complexes. In addition, chemical probe reactions with glyoxal were used to monitor the changes in the quadruplex conformation because of association with the complexes. The platinum phenanthroimidazole complexes show increased affinity for several of the quadruplexes with elongated loops between guanine repeats. Quadruplexes with shorter loops exhibited insubstantial binding to the transition metal complexes. Similarly binding to duplex and single strand oligonucleotides was low overall. Although the ruthenium‐based metal complex showed somewhat enhanced quadruplex binding, the PtII complexes had higher quadruplex affinities and selectivities that are attributed to their square planar geometries. The chemical probe reactions using glyoxal indicated increased reactivity when the platinum phenanthroimidazole complexes were bound to the quadruplexes, thus suggesting a conformational change that alters guanine accessibility. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 233–243, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Identification of Physiological and Toxic Conformations in Aβ42 Aggregates
Authors: Masuda Yuichi , Uemura Satoko , Ohashi Ryutaro , Nakanishi Azusa , Takegoshi K. , Shimizu Takahiko , Shirasawa Takuji , Irie Kazuhiro
Published: December 2008

Aggregation of the 42‐residue amyloid β‐protein (Aβ42) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Despite numerous structural studies on Aβ aggregates, the relationship between tertiary structure and toxicity remains unclear. Our proline scanning and solid‐state NMR studies suggested that aggregates both of wild‐type Aβ42 and of E22K‐Aβ42 (one of the mutants related to cerebral amyloid angiopathy) contain two conformers: a major one with a turn at positions 25 and 26, and a minor one with a turn at positions 22 and 23. To identify the toxic conformer, the derivative Aβ42‐lactam(22K–23E), in which the side chains at positions 22 and 23 were covalently linked, was synthesized as a minor conformer surrogate, along with Aβ42‐lactam(25K–26E) as a major conformer surrogate. The Aβ42‐lactam(22K–23E) showed stronger aggregation, neurotoxicity, radical generation, and oligomerization than wild‐type Aβ42, whereas in Aβ42‐lactam(25K–26E) were weak. The transition from the physiological conformation with a turn at positions 25 and 26 to the toxic conformation with a turn at positions 22 and 23 might be a key event in the pathogenesis of AD.
Hetero‐Seeding and Solid Mixture to Obtain New Crystalline Forms
Authors: Braga Dario , Grepioni Fabrizia , Maini Lucia , Polito Marco , Rubini Katia , Chierotti Michele R. , Gobetto Roberto
Published: December 2008

Para‐methyl benzyl alcohol (p‐MeBA II) and para‐chloro benzyl alcohol (p‐ClBA) are quasi‐isostructural and share the same hydrogen‐bond patterns, but their crystals are not isomorphous. No new polymorphs could be obtained by conventional polymorph screening based on different solvents and different crystallization conditions. Formation of a new polymorph of p‐MeBA named p‐MeBA I, isomorphous with the crystal of p‐ClBA, was induced by hetero‐seeding with a small quantity of powdered p‐ClBA added to a supersaturated solution of p‐MeBA in hexane, while seeding of p‐ClBA with p‐MeBA II failed to give a new phase of p‐ClBA isomorphous with known crystalline p‐MeBA II. Mixed crystals of p‐MeBA and p‐ClBA were also prepared with different p‐MeBA/p‐ClBA ratios to understand the role of the different functional groups in the crystal structure. Crystal phases were characterized by combined use of single‐crystal and powder X‐ray diffraction, differential scanning calorimetry, and solid‐state NMR spectroscopy.
Organic Ligand Binding by a Hydrophobic Cavity in a Designed Tetrameric Coiled‐Coil Protein
Authors: Mizuno Toshihisa , Hasegawa Chinatsu , Tanabe Yoichi , Hamajima Kenta , Muto Takashi , Nishi Yoshinori , Oda Masayuki , Kobayashi Yuji , Tanaka Toshiki
Published: December 2008

The design and characterization of a hydrophobic cavity in de novo designed proteins provides a wide range of information about the functions of de novo proteins. We designed a de novo tetrameric coiled‐coil protein with a hydrophobic pocketlike cavity. Tetrameric coiled coils with hydrophobic cavities have previously been reported. By replacing one Leu residue at the a position with Ala, hydrophobic cavities that did not flatten out due to loose peptide chains were reliably created. To perform a detailed examination of the ligand‐binding characteristics of the cavities, we originally designed two other coiled‐coil proteins: AM2, with eight Ala substitutions at the adjacent a and d positions at the center of a bundled structure, and AM2W, with one Trp and seven Ala substitutions at the same positions. To increase the association of the helical peptides, each helical peptide was connected with flexible linkers, which resulted in a single peptide chain. These proteins exhibited CD spectra corresponding to superhelical structures, despite weakened hydrophobic packing. AM2W exhibited binding affinity for size‐complementary organic compounds. The dissociation constants, Kd, of AM2W were 220 nM for adamantane, 81 μM for 1‐adamantanol, and 294 μM for 1‐adamantaneacetic acid, as measured by fluorescence titration analyses. Although it was contrary to expectations, AM2 did not exhibit any binding affinity, probably due to structural defects around the designed hydrophobic cavity. Interestingly, AM2W exhibited incremental structure stability through ligand binding. Plugging of structural defects with organic ligands would be expected to facilitate protein folding.
Protein Flexibility and Metal Coordination Changes in DHAP‐Dependent Aldolases
Authors: Jiménez Aurora , Clapés Pere , Crehuet Ramon
Published: December 2008

The mobility of rhamnulose‐1‐phosphate aldolase (RhuA) was analysed with a normal mode description and high level calculations on models of the active site. We report the connection between the mobility and the chemical properties of the active site, and compare them to a closely related enzyme, fuculose‐1‐phosphate aldolase (FucA). Calculations show that the different coordination number for the zinc ion, reported in the crystal structures of RhuA and FucA, was due to a different spatial arrangement of the residues, not to their different chemical nature. Moreover, the metal coordination change is correlated with activity. The domain mobility of the enzyme can reshape the active site of RhuA into the arrangement found in the FucA structure, and vice‐versa. This has a direct influence on the energy barrier for the aldol reaction catalyzed by these enzymes, thus showing a coupling of the domain movements and the catalytic effects. Hence domain movements and the coordination chemistry of the active site metal suggest an explanation of why these enzymes have similar experimental turnover rates.
Insights into Structure Direction of Microporous Aluminophosphates: Competition between Organic Molecules and Water
Authors: Gómez‐Hortigüela Luis , Pérez‐Pariente Joaquín , Corà Furio
Published: December 2008

A combination of experimental characterisation techniques and computational modelling has allowed us to gain insight into the molecular features governing structure direction in the synthesis of microporous aluminophosphates. The occlusion of three different structure‐directing agents (SDAs), triethylamine (TEA), benzylpyrrolidine (BP) and (S)‐(−)‐N‐benzylpyrrolidine‐2‐methanol (BPM), within the AFI structure during its crystallisation, together with the simultaneous incorporation of water, has been experimentally measured. We found a higher incorporation of organic molecules in the structure obtained with BPM, while a higher water (and lower organic) content is found for the ones obtained with TEA and BP as SDAs. The computational study provides a thermodynamic explanation for the observed behaviour in terms of the relative stabilisation energy of the SDAs and water molecules within the AFI framework compared with when they are in aqueous solution, and demonstrates that a competition for preferential occupation exists between water and organic SDAs, which is a function of the interaction with the inorganic framework. The lower interaction of TEA and BP molecules with the AFI structure promotes the simultaneous incorporation of water molecules in the 12‐membered‐ring (MR) channel, to increase the host–guest interaction energy and thus the thermodynamic stability. The presence of strongly interacting methanol groups in the BPM molecules leads to the incorporation of only organic molecules within the 12‐MR channels. Our results demonstrate the essential role that water molecules play in the stabilisation of hydrophilic microporous aluminophosphates; a minimum amount of organic SDA is, however, essential for a templating role of the microporous architecture.
Facile Functionalization of Multilayer Fullerenes (Carbon Nano‐Onions) by Nitrene Chemistry and “Grafting from” Strategy
Authors: Zhou Li , Gao Chao , Zhu Dandan , Xu Weijian , Chen Fanqing Frank , Palkar Amit , Echegoyen Luis , Kong Eric Siu‐Wai
Published: December 2008

Facile functionalization of multilayer fullerenes (carbon nano‐onions, CNOs) was carried out by [2+1] cycloaddition of nitrenes. The products were further derivatized by using the “grafting from” strategy of in situ ring‐opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Using one‐step nitrene chemistry with high‐energy reagents, such as azidoethanol and azidoethyl 2‐bromo‐2‐methyl propanoate, in N‐methyl‐2‐pyrrolidone at 160°C for 16 h, hydroxyl and bromide functionalities were introduced onto the surfaces of CNOs. These hydroxyl CNOs (CNO‐OH) and bromic CNOs (CNO‐Br) were extensively characterized by various techniques such as thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), Raman spectroscopy and X‐ray photo electron spectroscopy (XPS). TGA measurements indicated that the surface hydroxyl and bromide group density reached 1.49 and 0.49 mmol g−1, respectively. The as‐functionalized CNOs showed much better solubility in solvents than pristine CNOs. The CNO‐OH were also observed to fluoresce at λ=453 nm in water. The CNO‐OH and CNO‐Br can be conveniently utilized as macroinitiators to conduct surface‐initiated in‐situ polymerizations. Poly(ε‐caprolactone) (PCL, 45wt %) and polystyrene (PS, 60 wt%) were then grafted from surfaces of CNOs through the ROP of ε‐caprolactone with the macroinitiator CNO‐OH and the ATRP of styrene with the macroinitiator CNO‐Br, respectively. The structures and morphology of the resulting products were characterized by 1H NMR, scanning electron microscopy (SEM), TEM, and atomic force microscopy (AFM). The polymer functionalized CNOs have good solubility/dispersibility in common organic solvents. The facile and scalable functionalization approaches can pave the way for the comprehensive investigation of chemistry of CNOs and fabrication of novel CNO‐based nanomaterials and nanodevices.
C80Cl12: A Chlorine Derivative of the Chiral D2‐C80 Isomer—Empirical Rationale of Halogen‐Atom Addition Pattern
Authors: Simeonov Kalin S. , Amsharov Konstantin Yu , Jansen Martin
Published: December 2008

Welcome to the family! The constitution of the chiral D2‐C80 fullerene has been confirmed through single‐crystal X‐ray analysis of the chlorinated C80Cl12. The addition pattern of the chlorine atoms in the structure of C80Cl12 together with other structures of halogenated higher fullerenes is discussed. A stepwise principle of higher fullerene reactivity is proposed. Unusual short intermolecular chlorine–chlorine contacts are reported.

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