The variegated scallop, Mimachlamys varia, undergoes alterations in several of its metabolic pathways under short-term zinc exposure.

The variegated scallop (Mimachlamys varia) is a filter feeder bivalve encountered in marine regions of the Atlantic coast. In particular, it is present in the La Rochelle marina (France), where it is used for the biomonitoring of marine pollution, due to its ability to strongly bioaccumulate pollutants. In this semi-closed environment, contamination generated by port activities leads to an accumulation of both organic and metal pollutants. Zinc is one of these pollutants, present at a dose of up to 150 µg.L-1. This study investigated the effects of 48 h zinc exposure upon the metabolic profiles of Mimachlamys varia using UHPLC/QToF (ultra-high performance liquid chromatography-quadrupole time-of-flight) tandem mass spectrometry metabolomics. After acclimation in mesocosms recreating in situ conditions, both controls and exposed with Zn2+ (150 µg.L-1) bivalves were dissected to recover the gills after 48 h and stored at -80 °C before metabolites extraction. UHPLC/QToF tandem mass spectrometry was performed to study metabolite composition of samples. Statistical analysis of results using multivariate techniques showed a good classification between control and exposed groups. Eleven identified metabolites were found to be down-modulated in exposed scallops. These variations could reflect potential zinc effects on several of the biological processes, such as energy metabolism, osmoregulation and defense against oxidative stress. Among the eleven metabolites highlighted, four were reported for the first time in an aquatic organism exposed to Zn. This study demonstrates once again the diversity of interactions between bivalves and metals and the complexity of the physiological response of marine bivalves to pollutants.

Denosumab-mediated increase in hand bone mineral density associated with decreased progression of bone erosion in rheumatoid arthritis patients.

OBJECTIVE: Periarticular osteoporosis is one of the earliest radiographic signs of bone damage in rheumatoid arthritis (RA). Denosumab, an investigational fully human monoclonal antibody that binds to RANKL, inhibits bone erosion and systemic bone loss in clinical studies of patients with RA. In this hand bone mineral density (BMD) substudy, we investigated the effects of denosumab on hand BMD and its correlation with hand erosion scores. METHODS: Patients receiving methotrexate for erosive RA were randomized in a 1:1:1 ratio to receive subcutaneous placebo, denosumab 60 mg, or denosumab 180 mg at 0 and 6 months. Measurements included BMD (by dual x-ray absorptiometry [DXA]) of both hands (0, 1, 6, and 12 months), magnetic resonance images of the hands/wrists (0 and 6 months), and radiographs of the hands/wrists and feet (0, 6, and 12 months). RESULTS: There were 56 patients (13 placebo, 21 denosumab 60 mg, and 22 denosumab 180 mg). Mean changes in hand BMD at 6 and 12 months were: +0.8% and +1.0%, respectively, for denosumab 60 mg; +2.0% and +2.5%, respectively, for denosumab 180 mg; and -1.2% and -2.0%, respectively, for placebo. Erosion scores remained near baseline in the denosumab groups and increased from baseline in the placebo group. A negative correlation was observed between hand BMD and erosion scores. CONCLUSION: In patients with RA, denosumab provided protection against erosion, and not only prevented bone loss but increased hand BMD as measured by DXA.

Effect of adalimumab on joint disease: features of patients with psoriatic arthritis detected by magnetic resonance imaging.

BACKGROUND: Bone marrow oedema (BMO), synovitis, effusion and joint erosion on magnetic resonance imaging (MRI) may be used as outcome measures in psoriatic arthritis (PsA). OBJECTIVE: To assess the impact of adalimumab on BMO, synovitis, effusion and erosions in PsA, as measured by MRI. METHODS: Fifteen patients with active PsA (> or =3 tender and > or =3 swollen joints) were enrolled in an open-label pilot study. Each received adalimumab subcutaneously every other week for 24 weeks. MRI was obtained at baseline and 24 weeks. RESULTS: MRI was available for 11 patients, pre and post-therapy. BMO and effusion scores improved markedly after 24 weeks of adalimumab, while no significant change was noted in erosion score. An unanticipated finding, however, was the lack of improvement in the MRI synovitis score. CONCLUSIONS: Improvement in BMO and unchanged erosion scores may explain the "anti-erosive" effects of adalimumab in PsA. Persistence of BMO and synovitis on MRI suggests ongoing disease activity and supports the continuation of long-term anti-TNF therapy.

Adalimumab for long-term treatment of psoriatic arthritis: 2-year data from the Adalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT).

OBJECTIVE: To evaluate the long-term effectiveness and tolerability of adalimumab in the treatment of psoriatic arthritis (PsA). METHODS: Patients with PsA who completed a 24-week, double-blind study of adalimumab versus placebo were eligible to enroll in an open-label extension study and receive adalimumab 40 mg subcutaneously every other week for up to an additional 120 weeks. At the time of this analysis, available efficacy evaluations throughout 2 years of treatment (n = 245) included American College of Rheumatology (ACR) 20%, 50% and 70% improvement scores, measures of joint disease and skin disease, disability and quality of life; modified total Sharp scores (mTSS) were available for 2.75 years of treatment for patients who received adalimumab in the 24-week study. RESULTS: After 24 weeks of double-blind treatment, the mean change in mTSS was -0.2 for the adalimumab group (N = 144) and 1.0 for the placebo group (N = 152; p<0.001), and outcomes for all individual ACR component variables were significantly improved in adalimumab compared with placebo-treated patients. Compared with 24-week responses, inhibition of radiographic progression and improvements in joint disease were maintained in most patients during long-term, open-label adalimumab treatment. Also, improvements in skin disease were maintained, with >20% of patients achieving the strict criterion of psoriasis area and severity index 100. The nature and frequency of adverse events during long-term adalimumab treatment were consistent with the safety profile during short-term treatment. CONCLUSIONS: The clinical and radiographic efficacy of adalimumab demonstrated during short-term treatment was sustained during long-term treatment. Adalimumab has a favourable risk-benefit profile in patients with PsA. TRIAL REGISTRATION NUMBER: NCT00195689.

Radiographic progression of ankylosing spondylitis after up to two years of treatment with etanercept.

OBJECTIVE: To investigate the effect of etanercept therapy on radiographic progression in patients with ankylosing spondylitis (AS). METHODS: Patients with AS who had previously participated in a 24-week randomized, double-blind, placebo-controlled trial of etanercept therapy were enrolled in a 72-week open-label extension. Radiographs of the cervical and lumbar spine from patients who received etanercept (25 mg twice weekly) for up to 96 weeks were compared with radiographs from patients in a large prevalence cohort (Outcome Assessments in Ankylosing Spondylitis International Study [OASIS]) who had not been treated with anti-tumor necrosis factor alpha (anti-TNFalpha) agents. Radiographs obtained at 2 time points up to 96 weeks apart from patients in both study populations were digitized and read by 2 independent readers who were blinded with regard to patient group and sequence. The primary end point was the 96-week change in the modified Stoke AS Spine Score (mSASSS). RESULTS: A total of 257 patients treated with etanercept were compared with 175 unselected patients from the OASIS study. There was no significant difference in the change in the mSASSS from baseline among patients who received etanercept (mean +/- SD 0.91 +/- 2.45) versus those from the OASIS group (0.95 +/- 3.18). CONCLUSION: Unlike other inflammatory rheumatic diseases such as rheumatoid arthritis and psoriatic arthritis, structural progression in AS seems to be independent of TNF, despite the fact that TNF is responsible for the signs and symptoms due to inflammation in this disease.

Psoriatic arthritis and imaging.

Psoriatic arthritis (PsA) has historically been considered a milder rheumatic disease not yielding significant clinical damage. However, recent studies have shown that PsA can be deforming and debilitating and that joint damage can be severe. Traditionally, joint damage has been recorded using plain radiographs. Characteristic radiographic features of PsA include joint erosions, joint space narrowing, bony proliferation including periarticular and shaft periostitis, osteolysis including "pencil in cup" deformity and acro-osteolysis, ankylosis, spur formation, and spondylitis. New imaging modalities, including ultrasound, bone scanning, and magnetic resonance imaging may help in both diagnosis and follow up of patients with PsA. These new imaging techniques will with validation help detect early changes in the peripheral joints, the periarticular tissues, and the spinal structures in patients with PsA.

Interpreting radiographic data in rheumatoid arthritis.

Plain film radiography is the preferred method for evaluating disease progression in rheumatoid arthritis and for establishing the efficacy of new disease modifying antirheumatic agents. However, the relative efficacy of these agents cannot be determined by comparing radiographic data from different studies, and a standardised system is needed.

High-resolution inter-ictal SPET and phased-array MRI in partial epilepsy: an imaging comparison with video/EEG and outcome correlation.

To assess the clinical utility of high-resolution inter-ictal single photon emission tomography (SPET) of regional cerebral perfusion and high-resolution magnetic resonance imaging (MRI) of the brain with a phased-array temporal lobe coil, 35 patients with presumed partial epilepsy were evaluated prospectively by these techniques in addition to prolonged video/electroencephalographic (EEG) monitoring. Twenty of these patients had surgical treatment of partial epilepsy with outcome determinations spanning from 12 months to 3 years at follow-up. There were four categories of imaging findings as compared to scalp/sphenoidal EEG localization. Category I included 12 patients (34% of total) in whom there was complete imaging and EEG concordance. Category II included 4 patients (11%) in whom MRI and EEG were concordant but SPET was divergent or normal. Category III included 13 patients (37%) in whom SPET and EEG were concordant but MRI was divergent or normal. Category IV included 4 patients (11%) in whom neither SPET nor MRI was concordant with EEG. In this study, the relative sensitivities of SPET and MRI for localization of partial epilepsy based on prolonged scalp/sphenoidal video/EEG recordings were 76% and 49%, respectively. We conclude that these neuroimaging techniques (phased-array MRI and inter-ictal cerebral perfusion SPET) are complementary and useful in the pre-operative evaluation of patients with partial epilepsy.

Human synovial mast cell involvement in rheumatoid arthritis and osteoarthritis. Relationship to disease type, clinical activity, and antirheumatic therapy.

Mast cells were isolated by enzymatic digestion of synovium obtained from 48 patients with rheumatoid arthritis (RA) and 42 patients with osteoarthritis (OA). A significantly lower percentage of stainable synovial mast cells was obtained by tissue digestion from patients with clinically active RA compared with those with less active disease. The 54 patients treated with nonsteroidal antiinflammatory drugs had a significantly lower percentage of stainable synovial mast cells in cell suspension than did the other 36 patients. When anti-IgE antibody was used as a secretagogue in vitro, significantly greater histamine release was observed from synovial mast cells of RA patients compared with OA patients. Greater histamine release in response to anti-IgE was observed in the RA patients with more clinically active disease and those who were treated with prednisone, compared with RA patients without these features. Synovial mast cells of RA patients treated with a disease-modifying antirheumatic drug had a significantly lower mean histamine content than did cells from patients not receiving such treatment. Our data suggest that there are differences between synovial mast cells from tissues of patients with RA and OA and suggest that synovial mast cells may be activated in clinically active RA. In addition, the data indicate an effect of systemic antirheumatic therapy on mast cells isolated from synovium of patients with arthritis.

A single amino acid distinguishes the high-responder from the low-responder form of Fc receptor II on human monocytes.

The low-affinity Fc receptor on human peripheral blood monocytes (Fc gamma RIIA) is polymorphic with respect to its ability to bind murine IgG1. The two allelic forms of the receptor, high responder (HR) and low responder (LR), yield characteristic patterns after isoelectric focusing and react differently with the anti-Fc gamma RII monoclonal antibody (mAb), 41H16. We recently cloned cDNA encoding the extracellular domains of Fc gamma RIIA on monocytes from one HR and two LR donors, and found that they differed at only a single base. The cDNA isolated from the HR donor had a G at position 519 and would be expected to encode an aginine at residue 133 in the mature protein, while the cDNA isolated from both LR donors had an A at position 519 and would be expected to encode a histidine at the same residue. To determine whether this single amino acid substitution actually accounts for the functional polymorphism involving Fc gamma RIIA, we transfected COS cells with full-length HR and LR Fc gamma RIIA cDNA, and examined them for their ability to react with anti-Fc gamma RIIA mAb and to bind red blood cells (RBC) coated with either murine IgG2b or murine IgG1. Whereas COS cells transfected with either the HR cDNA or the LR cDNA reacted with the anti-Fc gamma RII mAb, IV.3, and bound murine IgG2b-coated RBC, only COS cells transfected with the HR cDNA formed rosettes with murine IgG1-coated RBC and reacted strongly with mAb 41H16. A total of nine LR donors were identified, and all were homozygous for the A substitution at position 519. We conclude that at an A at position 519 in the cDNA encoding Fc gamma RIIA is the primary molecular basis for the LR form of the receptor, and that the amino acid at residue 133 determines whether Fc gamma RIIA efficiently binds murine IgG1.

Transfected NA1 and NA2 forms of human neutrophil Fc receptor III exhibit antigenic and structural heterogeneity.

Human neutrophils express two polymorphic forms (NA1 and NA2) of Fc receptor III (FcRIII), which differ structurally and antigenically. We recently isolated FcRIII cDNAs from NA1NA1 and NA2NA2 homozygotes and determined that they differ only at five nucleotides, predicting four amino acid substitutions. To determine whether the cDNAs that we isolated actually encode proteins that differ structurally and that react appropriately with anti-NA1 and anti-NA2 antibodies, we transfected Chinese hamster ovary (CHO) cells with constructs containing either the NA1 FcRIII cDNA or the NA2 FcRIII cDNA. The receptors on transfected CHO cells were then compared with the receptors on normal human neutrophils from an NA1NA2 heterozygote. After immunoprecipitation and treatment with N-glycanase, receptors isolated from surface-labeled CHO cells transfected with the NA1 FcRIII cDNA had an apparent molecular mass of 29 Kd after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), while the receptors isolated from CHO cells transfected with the NA2 FcRIII cDNA had an apparent molecular mass of 33 Kd. Identical 29-Kd and 33-Kd bands were observed when receptors isolated from surface-labeled neutrophils of an NA1NA2 heterozygote were treated similarly. Using a cell-free rabbit reticulocyte lysate system, we translated NA1 FcRIII and NA2 FcRIII RNAs in vitro and also found differences in the apparent molecular masses of the two forms of the receptor. Finally, reactivity of transfected CHO cells with anti-NA monoclonal and alloantibodies confirmed that the cDNAs we isolated actually encode the NA1 and NA2 forms of neutrophil FcRIII.

An abnormality of the gene that encodes neutrophil Fc receptor III in a patient with systemic lupus erythematosus.

In the course of examining the structure and function of Fc receptors on peripheral blood cells of patients with systemic lupus erythematosus, we identified a patient whose neutrophils did not react with either monoclonal or polyclonal antibodies to Fc receptor III. However, neutrophils from the patient were comparable to neutrophils from healthy controls with respect to their expression of Fc receptor II, complement receptor 1, complement receptor 3, and the phosphatidylinositol-linked, complement regulatory protein, decay-accelerating factor. The abnormality of expression of Fc receptor III was limited to the patient's neutrophils (her natural killer cells reacted normally with anti-Fc receptor III antibodies), and was associated with abnormal recognition and binding of IgG-coated erythrocytes. Analysis of genomic DNA revealed evidence that failure of the patient's neutrophils to express Fc receptor III was most likely due to an abnormality of the gene that encodes this receptor.

Sequences of complementary DNAs that encode the NA1 and NA2 forms of Fc receptor III on human neutrophils.

Two polymorphic forms of Fc receptor III (FcR III) are expressed on human neutrophils. These differ with respect to their apparent molecular masses after digestion with N-glycanase, and with respect to their reactivity with MAb Gran 11 and alloantisera which recognize determinants (NA1 and NA2) of the biallelic neutrophil antigen (NA) system. To determine the molecular basis for this polymorphism we isolated RNA from neutrophils of NA1NA1 and NA2NA2 homozygotes and synthesized corresponding cDNAs. cDNAs encoding FcR III were then amplified using the polymerase chain reaction, cloned, and sequenced. The cDNA that encodes FcR III on NA1NA1 neutrophils differed from the cDNA that encodes FcR III on NA2NA2 neutrophils at five nucleotides, predicting four amino acid substitutions. As a result, NA1 FcR III has only four potential N-linked glycosylation sites as compared with six in NA2 FcR III. The amino acid substitutions and differences in the number of potential N-linked glycosylation sites probably account for the different forms of neutrophil FcR III observed after digestion with N-glycanase and for the antigenic heterogeneity of this receptor.

Molecular basis for a polymorphism involving Fc receptor II on human monocytes.

IgG Fc receptor II (Fc gamma RII) on human monocytes is polymorphic with respect to its appearance on gels after isoelectric focusing and with respect to its ability to mediate T lymphocyte proliferation induced by murine anti-CD3 mAb of the IgG1 isotype (i.e., its ability to bind murine IgG1). To determine the molecular basis for this polymorphism, we isolated total cellular RNA from PBMC of responders and nonresponders (defined by Leu-4-induced [3H] thymidine incorporation) and synthesized corresponding cDNA. Sequences encoding the extracellular domain of Fc gamma RII were then amplified using the Taq polymerase chain reaction. Amplified DNA fragments were cloned into pUC vectors, and sequenced. Analysis of clones from two nonresponders revealed a single base change (G for A) at position 519, which would result in the substitution of a histidine for an arginine at residue 133 in the mature Fc gamma RII protein. These findings suggest that the polymorphism involving human monocyte Fc gamma RII results from allelic variation of a single gene.

Characterization of polymorphic forms of Fc receptor III on human neutrophils.

We characterized Fc receptor III (FcR III) on human neutrophils and found it to be heavily glycosylated and polymorphic. In some individuals, FcR III that had been digested with N-glycanase appeared after SDS-PAGE under reducing conditions as two bands with apparent molecular masses of 33 and 29 kD. In other individuals, N-glycanase-treated FcR III appeared as a single band with an Mr of either 33 or 29 kD. After SDS-PAGE of N-glycanase-treated FcR III under nonreducing conditions, the apparent Mr of each structural type was decreased, suggesting the presence of intramolecular disulfide bonds. Digestion of the 33-kD band and the 29-kD band with Staphylococcus aureus V8 protease yielded similar, but not identical, peptide maps. Thus, at least two polymorphic forms of FcR III are expressed on human neutrophils. The structural polymorphism of neutrophil FcR III correlated with previously described antigenic polymorphisms detected by monoclonal antibody Gran 11 and by alloantisera which recognize epitopes of the biallelic, neutrophil antigen (NA) system. Individuals whose neutrophils expressed the two-band structural type of FcR III were NA1NA2 heterozygotes. Individuals whose neutrophils expressed the single 33-kD band structural type were NA2NA2 homozygotes, and individuals whose neutrophils expressed the single 29-kD band structural type were NA1NA1 homozygotes. These findings indicate that antigenic and structural polymorphisms of human neutrophil FcR III are related and can be accounted for by differences at the level of primary protein structure.

CD16. Developmentally regulated IgG Fc receptors on cultured human monocytes.

We have demonstrated that one Fc receptor for IgG (FcR) (CD16) on cultured human monocytes appears to be a developmentally regulated membrane protein. This receptor appears to contain less carbohydrate (if any) than does its counterpart on human neutrophils. Expression of CD16 on cultured monocytes increases with respect to both percentage of positive cells and numbers of sites per cell with length of time in culture. This was in contrast to expression of other types of FcRs that either decreased (CDw32) or did not change (FcRp72). Unlike an FcR that binds monomeric IgG (FcRp72), expression of CD16 on monocytes from most normal individuals was not influenced by IFN-gamma. After 14 d in culture, CD16 appeared to be the predominant FcR on cultured monocytes, and was capable of mediating both ligand attachment and phagocytosis. These findings support the hypothesis that CD16 plays an important role in mediating immunophagocytosis.