The glycoimmune checkpoint receptor Siglec-7 interacts with T-cell ligands and regulates T-cell activation

Siglec-7 (sialic acid-binding immunoglobulin-like lectin 7) is a glycan-binding immune receptor that is emerging as a significant target of interest for cancer immunotherapy. The physiological ligands that bind Siglec-7, however, remain incompletely defined. In this study, we characterized the expression of Siglec-7 ligands on peripheral immune cell subsets and assessed whether Siglec-7 functionally regulates interactions between immune cells. We found that disialyl core 1 O-glycans are the major immune ligands for Siglec-7 and that these ligands are particularly highly expressed on naïve T-cells. Densely glycosylated sialomucins are the primary carriers of these glycans, in particular a glycoform of the cell-surface marker CD43. Biosynthesis of Siglec-7-binding glycans is dynamically controlled on different immune cell subsets through a genetic circuit involving the glycosyltransferase GCNT1. Siglec-7 blockade was found to increase activation of both primary T-cells and antigen-presenting dendritic cells in vitro, indicating that Siglec-7 binds T-cell glycans to regulate intraimmune signaling. Finally, we present evidence that Siglec-7 directly activates signaling pathways in T-cells, suggesting a new biological function for this receptor. These studies conclusively demonstrate the existence of a novel Siglec-7-mediated signaling axis that physiologically regulates T-cell activity. Going forward, our findings have significant implications for the design and implementation of therapies targeting immunoregulatory Siglec receptors.

How developmental coordination disorder affects daily life: The adolescent perspective

BACKGROUND

Few studies have focused on the implications of developmental coordination disorder (DCD) in the teen years. Understanding the unique needs of adolescents with DCD and the challenges they face are imperative to inform clinical care.

AIM

To understand how DCD affects daily life from adolescents living with the disorder.

METHODS

Participants were recruited from a database of adolescents who were formally diagnosed with DCD in childhood. Nineteen semi-structured interviews of adolescents with DCD (13-18 years) were conducted and analyzed using an interpretive description approach.

RESULTS

Data analysis revealed four overarching themes: (1) Through the years; (2) Standing out, left out, opting out; (3) Rising into Resilience; and (4) Help me to be me. Adolescents with DCD face challenges in physical, cognitive, social, emotional, and mental health domains, but their success can be optimized through provision of support, fostering social connections, the use of strategies, and increasing public understanding. Few services currently exist for adolescents with DCD, as treatment is not standard of care.

CONCLUSIONS AND IMPLICATIONS

Insights gained from this study provide client-centred evidence to advocate for intervention for adolescents with DCD, and guide recommendations for clinical care and community support to meet the needs of this under-served population. WHAT THIS PAPER ADDS?: This paper qualitatively explores the lived experience of adolescents with DCD, adding to the limited research within this population. Expanding beyond the typical focus of motor challenges, this paper highlights the widespread influence of DCD on daily life, including in cognitive, mental health, and social-emotional domains. Common environmental contexts that exacerbate challenges during adolescent years are explored, including high school PE class and electives, learning to drive, beginning employment, and preparing for post-secondary education. Through an interpretive description methodology, this paper delves into clinical and practical solutions to support adolescents with DCD, from an individualized and client-centered perspective.

Identification of association fibers using ex vivo diffusion tractography in Alexander disease brains

BACKGROUND AND PURPOSE

Alexander disease (AxD) is a neurodegenerative disorder caused by heterozygous Glial Fibrillary Acidic Protein mutation. The characteristic structural findings of AxD, such as leukodystrophic features, are well known, while association fibers of AxD remain uninvestigated. The aim of this study was to explore global and subcortical fibers in four brains with AxD using ex vivo diffusion tractography METHODS: High-angular-resolution diffusion magnetic resonance imaging (HARDI) tractography and diffusion-tensor imaging (DTI) tractography were used to evaluate long and short association fibers and compared to histological findings in brain specimens obtained from four donors with AxD and two donors without neurological disorders RESULTS: AxD brains showed impairment of long association fibers, except for the arcuate fasciculus and cingulum bundle, and abnormal trajectories of the inferior longitudinal and fronto-occipital fasciculi on HARDI tractography and loss of multidirectionality in subcortical fibers on DTI tractography. In histological studies, AxD brains showed diffuse low density on Klüver-Barrera and neurofilament staining and sporadic Rosenthal fibers on hematoxylin and eosin staining CONCLUSIONS: This study describes the spatial distribution of degenerations of short and long association fibers in AxD brains using combined tractography and pathological findings.

Cortical Thickness Abnormalities in Attention Deficit Hyperactivity Disorder Revealed by Structural Magnetic Resonance Imaging: Newborns to Young Adults

Attention deficit hyperactivity disorder is a neurodevelopmental condition for which we have an incomplete understanding, and so brain imaging methods, such as magnetic resonance imaging (MRI) may be able to assist in characterizing and understanding the presentation of the brain in an ADHD population. Statistical and computational methods were used to compare participants with attention deficit hyperactivity disorder (ADHD) and neurotypical controls at a variety of developmental stages to assess detectable abnormal neurodevelopment potentially associated with ADHD and to assess our ability to diagnose and characterize the condition from real-world clinical magnetic resonance imaging (MRI) examinations. T1-weighted structural MRI examinations (n=993; 0-31 years old [YO]) were obtained from neurotypical controls and 637 examinations were obtained from patients with ADHD (0-26 YO). Measures of average (mean) regional cortical thickness were acquired, alongside the first reporting of regional cortical thickness variability (as assessed with the standard deviation [SD]) in ADHD. A comparison between the inattentive and combined (inattentive and hyperactive) subtypes of ADHD is also provided. A preliminary independent validation was also performed on the publicly available ADHD200 dataset. Relative to controls, subjects with ADHD had, on average, lowered SD of cortical thicknesses and increased mean thicknesses across several key regions potentially linked with known symptoms of ADHD, including the precuneus, supramarginal gyrus, etc.

Bridging Glycomics and Genomics: New Uses of Functional Genetics in the Study of Cellular Glycosylation

All living cells are coated with a diverse collection of carbohydrate molecules called glycans. Glycans are key regulators of cell behavior and important therapeutic targets for human disease. Unlike proteins, glycans are not directly templated by discrete genes. Instead, they are produced through multi-gene pathways that generate a heterogenous array of glycoprotein and glycolipid antigens on the cell surface. This genetic complexity has sometimes made it challenging to understand how glycosylation is regulated and how it becomes altered in disease. Recent years, however, have seen the emergence of powerful new functional genomics technologies that allow high-throughput characterization of genetically complex cellular phenotypes. In this review, we discuss how these techniques are now being applied to achieve a deeper understanding of glyco-genomic regulation. We highlight specifically how methods like ChIP-seq, RNA-seq, CRISPR genomic screening and scRNA-seq are being used to map the genomic basis for various cell-surface glycosylation states in normal and diseased cell types. We also offer a perspective on how emerging functional genomics technologies are likely to create further opportunities for studying cellular glycobiology in the future. Taken together, we hope this review serves as a primer to recent developments at the glycomics-genomics interface.

Neutropenia in patients under treatment with clozapine and COVID-19 infection

Introduction

Clozapine is among the most effective antipsychotics used for treatment resistant schizophrenia. Adverse reactions to clozapine include neutropenia. Case series report that clozapine-treated patients with COVID-19 have no documented neutropenia.

Objectives

We sought to investigate the potential adverse effect of coronavirus disease (COVID-19) in patients taking clozapine.

Methods

We retrospectively inspected data of 13 consecutive patients on clozapine, admitted to Highgate Mental Health Centre -Camden & Islington NHS Foundation Trust between March and June 2020. Selection was based on their COVID-19 symptoms presentation and/or COVID-19 positive test. We used a linear regression model with COVID status as independent variable and absolute neutrophil count (ANC) as dependent variable to inform about a correlation between COVID-19 status and neutrophil count. STATA was used for statistics.

Results

We collected data on thirteen patients of which nine were male. The median age was of 41.97 years; six subjects were Black, three were Asian and four were White Caucasian. Ten subjects tested positive to COVID-19 and 3 were suspected cases -these latter were excluded from stastical analysis. During COVID-19 infection, neutrophils count (ANC) dropped significantly to 4.215 from a baseline value of 5.337. The beta values of 0.83 shows that ANC declined significantly during COVID-19 infection (p =<.0001, R2 = 95%). In three of thirteen patients, ANC drop was significant and changed the patients’ monitoring status from green to amber and required frequent blood tests.

Conclusions

Clinicians should bear in mind that a significant drop in neutrophils count may occur in COVID-19 -infected patients taking clozapine.

Disclosure

No significant relationships.

Clinical presentation, sonographic features and treatment options of segmental stiff skin syndrome

Segmental stiff skin syndrome is a rare genetic connective tissue disease, which is often misdiagnosed. High-frequency ultrasonography can represent a useful clinical adjunct in the differential diagnosis of this condition, in conjunction with the clinical and histopathological findings. Treatment options are limited and evidence is scarce. We present the clinical, sonographic and histological features of five paediatric patients diagnosed at our institution and discuss their response to treatment.

Structural and Diffusion MRI Analyses With Histological Observations in Patients With Lissencephaly

The development of cortical convolutions, gyri and sulci, is a complex process that takes place during prenatal development. Lissencephaly, a rare genetic condition characterized by the lack of cortical convolutions, offers a model to look into biological processes that lead to the development of convolutions. Retrospective, qualitative, and quantitative analyses of structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were performed in patients with lissencephaly (N = 10) and age-/sex-matched controls (N = 10). In order to identify microstructural correlates of structural MRI and DTI findings, postmortem brains of patients with lissencephaly (N = 4) and age-matched controls (N = 4) were also examined with histology. Patients with lissencephaly had significantly smaller gyrification index and volumes of hemispheric white and gray matter, compared to the age-/sex-matched control group. However, there was no significant difference between groups in the subcortical gray matter volumes. Although the majority of patients with lissencephaly had a preserved normal-like appearance of major fissures and primary sulci, the spatial distribution of agyric cortical regions was different in patients with lissencephaly-1 (LIS1) and doublecortin (DCX) mutations. Lastly, in patients with lissencephaly, the spatiotemporal distribution of projection pathways was preserved while short- to medium-range cortico-cortical pathways were absent or fewer in number. Our results indicate that in the patients with lissencephaly cortical system is affected more than the subcortical one.

Structural magnetic resonance imaging demonstrates abnormal cortical thickness in Down syndrome: Newborns to young adults

Down syndrome (DS) is a genetic disorder caused by an extra copy of all or part of chromosome 21 and is characterized by intellectual disability. We performed a retrospective analysis of 47 magnetic resonance imaging (MRI) examinations of participants with DS (aged 5 to 22 years) and compared them with a large cohort of 854 brain MRIs obtained from neurotypical participants (aged 5 to 32 years) with the objective of assessing the clinical presentation of Down syndrome, towards better understanding the neurological development associated with the condition. An additional cohort of 26 MRI exams from patients with DS and 139 exams from neurotypical participants (aged 0–5 years) are included as part of a supplementary analysis. Regionally distributed cortical thickness measurements, including average measurements as well as standard deviations (intra-regional cortical thickness variability) were extracted from each examination. The largest effect sizes observed were associated with increased average cortical thickness in the postcentral gyrus with specific abnormalities observed in Brodmann's areas 1 and 3b in DS, which was observed across all age ranges. We also observed strong effect sizes associated with decreased cortical thickness variability in the lateral orbitofrontal gyrus, the postcentral gyrus and more in DS participants. Findings suggest regionally irregular gray matter development in DS that can be detected with MRI.

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Large scale study of the clinical presentation of Down Syndrome

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Abnormally increased mean cortical thicknesses identified in key regions.

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Abnormally decreased variability in cortical thicknesses identified within key regions

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Findings may be connected with abnormal pruning in Down Syndrome.

Absence of cytotoxic and inflammatory effects following in vitro exposure of chondrogenically-differentiated human mesenchymal stem cells to adenosine, lidocaine and Mg2+ solution

Background

ALM solution, a combination of adenosine, lidocaine and Mg²⁺, is an emerging small volume therapy that has been shown to prevent and correct coagulopathy and surgery-related inflammation in preclinical models, though its application in orthopaedic surgery is yet to be demonstrated. The effect of ALM solution on chondrocytes is unknown. The aim of this preliminary study was to investigate the effect of ALM solution on viability and inflammatory responses of chondrogenically-differentiated human bone marrow-derived mesenchymal stem cells (chondro-MSC), in vitro.

Methods

Chondro-MSC were exposed to media only, saline (0.9% NaCl or 1.3% NaCl) only, or saline containing ALM (1 mM adenosine, 3 mM lidocaine, 2.5 mM Mg²⁺) or tranexamic acid (TXA, 100 mg/ml) for 1 or 4 h. Responses to ALM solutions containing higher lidocaine concentrations were also compared. Chondrocyte viability was determined using WST-8 colorimetric assays and inflammatory cytokine (TNF-α, IL-1β, IL-8) and matrix metalloproteinases (MMP-3, MMP-12, MMP-13) concentrations using multiplex bead arrays.

Results

The viability of chondro-MSC was significantly greater after 1 h treatment with ALM compared to saline (96.2 ± 7.9 versus 75.6 ± 7.3%). Extension of exposure times to 4 h had no significant adverse effect on cell viability after treatment with ALM (1 h, 85.4 ± 5.6 v 4 h, 74.0 ± 15.2%). Cytotoxicity was evident following exposure to solutions containing lidocaine concentrations greater than 30 mM. There were no significant differences in viability (80 ± 5.4 v 57.3 ± 16.2%) or secretion of IL-8 (60 ± 20 v 160 ± 50 pg/ml), MMP-3 (0.95 ± 0.6 v 3.4 ± 1.6 ng/ml), and MMP-13 (4.2 ± 2.4 v 9.2 ± 4.3 ng/ml) in chondro-MSC exposed to saline, ALM or TXA.

Conclusions

Short-term, in vitro exposure to clinically-relevant concentrations of ALM solution had no adverse inflammatory or chondrotoxic effects on human chondro-MSC, with responses comparable to saline and TXA. These findings provide support for continued evaluation of ALM solution as a possible therapeutic to improve outcomes following orthopaedic procedures.

Structural Magnetic Resonance Imaging Demonstrates Abnormal Regionally-Differential Cortical Thickness Variability in Autism: From Newborns to Adults

Autism is a group of complex neurodevelopmental disorders characterized by impaired social interaction and restricted/repetitive behavior. We performed a large-scale retrospective analysis of 1,996 clinical neurological structural magnetic resonance imaging (MRI) examinations of 781 autistic and 988 control subjects (aged 0–32 years), and extracted regionally distributed cortical thickness measurements, including average measurements as well as standard deviations which supports the assessment of intra-regional cortical thickness variability. The youngest autistic participants (<2.5 years) were diagnosed after imaging and were identified retrospectively. The largest effect sizes and the most common findings not previously published in the scientific literature involve abnormal intra-regional variability in cortical thickness affecting many (but not all) regions of the autistic brain, suggesting irregular gray matter development in autism that can be detected with MRI. Atypical developmental patterns have been detected as early as 0 years old in individuals who would later be diagnosed with autism.

Regional volumetric abnormalities in pediatric autism revealed by structural magnetic resonance imaging

Autism is a group of complex neurodevelopmental disorders characterized by impaired social interaction, restricted and repetitive behavior. We performed a large-scale retrospective analysis of 1,996 structural magnetic resonance imaging (MRI) examinations of the brain from 1,769 autistic and neurologically typically developing patients (aged 0-32 years), and extracted regional volumetric measurements distributed across 463 brain regions of each patient. The youngest autistic patients (<2.5 years) were diagnosed after imaging and identified retrospectively. Our study demonstrates corpus callosum volumetric abnormalities among autistic patients that are associated with brain overgrowth in early childhood (0-5 years old), followed by a shift towards known decreased volumes in later ages. Results confirm known increases in ventricular volumes among autistic populations and extends those findings to increased volumes of the choroid plexus. Our study also demonstrates distributed volumetric abnormalities among autistic patients that affect a variety of key regional white and grey matter areas of the brain potentially associated with known symptoms of autism.

Modulating effects of WT1 on interferon-β-vitamin D association in MS

OBJECTIVE

To investigate whether those genes involved in the vitamin D pathway modulate the relationship between 25-hydroxyvitamin D (25(OH)D) and IFN-β, the relationship between IFN-β and sun in predicting 25(OH)D, and the interaction between IFN-β and 25(OH)D in modulating relapse risk in patients with MS.

METHODS

Prospective cohort study of 169 participants with MS and genotype data followed 2002-2005. Gene-IFN-β and gene-IFN-β-sun interactions predicting 25(OH)D evaluated by multilevel mixed-effects linear regression. Gene-IFN-β interactions with 25(OH)D in modulating in relapse risk assessed using survival analysis.

RESULTS

The cohort was 71.6% female and of mean age 47.8. Two-independent intronic genotyped SNPs (rs10767935 and rs5030244) in WT1 significantly modified the IFN-β-25(OH)D association after adjustment (P(interaction) = 0.001, 0.0002; P(adj) = 0.003, 0.006, respectively). There was a marked difference in the interaction between self-reported sun exposure and IFN-β in predicting 25(OH)D by level of rs10767935, although this did not reach statistical significance. No SNPs modified the interaction between IFN-β and 25(OH)D in predicting relapse.

CONCLUSIONS

We have demonstrated that two-independent SNPs (rs10767935 and rs5030244) in WT1 modified the IFN-β-25(OH)D association in patients with MS. Some evidence was shown for a difference in the sun-IFN-β-25(OH)D association by level of rs10767935. These findings indicate that WT1 variants may play a role in altering the effects of IFN-β on vitamin D in MS.

Human body projectiles implantation in victims of suicide bombings and implications for health and emergency care providers: the 7/7 experience

INTRODUCTION

On 7 July 2005 four suicide bombings occurred on the London transport systems. In some of the injured survivors, bone fragments were embedded as biological foreign bodies. The aim of this study was to revisit those individuals who had sustained human projectile implantation injuries as a result of the bomb blasts at all scenes, review the process of body parts mapping and DNA identification at the scene, detail the management of such injuries and highlight the protocols that have been put in place for protection against blood borne pathogens.

METHODS

We retrospectively reviewed 12 instances of victims who sustained human body projectile implantation injuries. The Metropolitan Police and forensic scientists identified the human projectiles using DNA profiling and mapped these on the involved carriages and those found outside. All human projectiles included were greater than 3cm².

RESULTS

Twelve cases had human projectile implantation injuries. Of these, two died at the scene and ten were treated in hospital. Projectiles were mapped at three of the four bomb blast sites. Our findings show that victims within a 2m radius of the blast had human projectile injuries. Eight of the allogenic bony fragments that were identified in the survivors originated from the suicide bomber. All the victims with an open wound should have prophylaxis against hepatitis B and serum stored for appropriate action against HIV and hepatitis C infection.

CONCLUSIONS

All victims following a suicide bombing should be assumed to have human body projectile implantation injuries with blood products or bony fragments. All immediate care providers should receive prophylaxis against hepatitis B virus and appropriate action should be taken against HIV and hepatitis C infection.

Antenatal depression in socially high-risk women in Canada

BACKGROUND

Antenatal depression is potentially deleterious to the mother and baby. Canadian Aboriginal women have an increased risk for living in poverty, family violence, and substance use; however, little is known about antenatal depression in this group. The aim of this study was to determine the prevalence and correlates of depression in socially high-risk, mostly Aboriginal pregnant women.

METHODS

Women (Aboriginal and non-Aboriginal), in two prenatal outreach programmes were approached and depressive symptoms between the two groups were compared, using the Edinburgh Postnatal Depression Scale (EPDS).

RESULTS

Sixty per cent (n = 402) of potential participants were recruited for the study. The prevalence of depression was 29.5% (n = 402). Depression was associated with a history of depression, mood swings, increased stressors, current smoker, and lack of social support. Aboriginal women were more likely to be depressed, but this was not significantly higher than non-Aboriginal women; however, they did experience significantly more self-harm thoughts. Exercise was a significant mediator for depression.

CONCLUSION

The prevalence of antenatal depression confirms rates in other high-risk, ethnic minority groups of women. A previous history of depression and mood problems were associated with depression, thus prenatal care should include a careful mental health assessment. On a positive note, the present study suggests that exercise may mediate antenatal depression.

Abnormal haemoglobin levels in acute coronary syndromes

BACKGROUND

Anaemia is an adverse prognostic marker in acute coronary syndromes (ACS), but the epidemiology of abnormal haemoglobin levels in such patients is uncertain.

AIMS

To investigate the prevalence, nature and predictors of abnormal haemoglobin levels in ACS patients at admission.

DESIGN

Observational study.

METHODS

All emergency admissions from January to April 2005 were assessed within 24-48 h of hospital admission. ACS patients (unstable angina, non-ST-elevation or ST-elevation myocardial infarction) were enrolled (n = 320, 190 men). Clinical information was recorded.

RESULTS

Overall, 71% had unstable angina; 18% non-ST-elevation myocardial infarction (MI), and 11% ST-elevation MI. Mean +/- SD haemoglobin was 14.3 +/- 1.7 g/dl in men and 13.2 +/- 1.5 g/dl in women. Abnormal haemoglobin was more common in men (65, 34%) than in women (34, 22%) (p = 0.013). Anaemia (haemoglobin <13 g/dl in men, or <12.0 g/dl in women) was recorded in 35 (18%) men and 24 (18%) women. All had admission haemoglobin >8 g/dl, and anaemia was usually normocytic. Multivariate predictors of anaemia (OR, 95%CI) were age (1.07, 1.04-1.1) and serum albumin (0.90, 0.81-1.00). Elevated haemoglobin (>16 g/dl) was recorded in 30 (16%) men and 4 (3%) women (p < 0.01), and was more common in ST-elevation MI patients (26%) than in unstable angina or non-ST elevation MI patients (9%) (p = 0.005). In patients who underwent invasive management with a post-procedure haemoglobin the following day (n = 85), 15 (18%) new cases of anaemia were detected. Admission duration correlated with haemoglobin (p < 0.01), creatinine (p < 0.01), troponin I (p < 0.01) and C-reactive protein (p < 0.01). Anaemia was more common in those who died in hospital (3, 60%) than in those who survived (56, 18%) (adjusted p = 0.0135).

DISCUSSION

Abnormal haemoglobin levels were common in our ACS admissions. Anaemia was generally mild. Increasing age and interventional management were associated with anaemia, which in turn was associated with adverse in-hospital outcomes. Interventions to prevent and detect anaemia in this setting merit prospective testing.

MRI bone oedema predicts eight year tendon function at the wrist but not the requirement for orthopaedic surgery in rheumatoid arthritis

OBJECTIVE

To investigate the role of early magnetic resonance imaging (MRI) of the wrist in predicting functional outcome in rheumatoid arthritis.

METHODS

MRI scans of the dominant wrist were scored for synovitis, tendon inflammation, bone oedema, and erosion at first presentation (n = 42), at 1 year (n = 42), and at 6 years (n = 31). At 8 years, clinical reassessment (n = 28) was undertaken. Tendon function was graded 0-3 for movement, tendon sheath swelling, and pain on resistance at nine flexor and extensor tendons of the hand. Hand function was also assessed using the Sollerman grip test. The requirement for joint or tendon surgery by 8 years was determined by telephone survey in 39 of the original 42 patients.

RESULTS

At 8 years, tendon function was highly correlated with hand function (Sollerman score, R = -0.51, p = 0.005) and global function (health assessment questionnaire score, R = 0.53, p = 0.004). Using a model incorporating baseline and 1 year MRI scores, the MRI bone oedema score was strongly predictive of tendon function at 8 years (chi(2)(2) = 15.3, p = 0.0005), as was the MRI bone erosion score (chi(2)(2) = 9.23, p = 0.01). Hand function was also predicted by the baseline MRI erosion score (p = 0.02). MRI variables did not predict the requirement for surgery, but patients who had surgery were more likely to show progression of MRI bone erosion scores between baseline and 1 year (p = 0.008).

CONCLUSIONS

Extensive MRI bone oedema and erosions at the wrist in early rheumatoid arthritis predict tendon dysfunction and impaired hand function in the medium term but not the requirement for joint or tendon surgery.

MRI of the wrist in early rheumatoid arthritis can be used to predict functional outcome at 6 years

OBJECTIVES

To determine whether magnetic resonance (MR) scans of the dominant wrist of patients with early rheumatoid arthritis (RA) can be used to predict functional outcome at 6 years' follow up.

METHODS

Dominant wrist MR scans were obtained in 42 patients with criteria for RA at first presentation. Patients were followed up prospectively for 6 years, and further scans obtained at 1 year (42 patients) and 6 years (31 patients). Two radiologists scored scans for synovitis, tendonitis, bone oedema, and erosions. The Stanford Health Assessment Questionnaire (HAQ) score, indicating functional outcome, and standard measures of disease activity were assessed at 0, 1, 2, and 6 years. The physical function component of the SF-36 score (PF-SF36) was also used as a functional outcome measure at 6 years.

RESULTS

Baseline MR parameters, including bone oedema score and the total baseline MR score, were predictive of the PF-SF36 at 6 years (R2 = 0.22, p = 0.005 and R2 = 0.16, p = 0.02, respectively). The PF-SF36 score correlated strongly with the HAQ score at 6 years (rs = -0.725, p<0.0001); none of the baseline MR parameters predicted the 6 year HAQ score. The total MR score obtained at 1 year was predictive of the 6 year HAQ (R2 = 0.04, p = 0.01). Standard clinical and radiographic measures at baseline were not predictive of the 6 year PF-SF36, but when combined in a model with baseline MR oedema score, prediction increased from 0.09 to 0.23, or 23% of the 6 year variance.

CONCLUSION

MR imaging of the wrist in patients with early RA can help to predict function at 6 years and could be used to plan aggressive management at an earlier stage.

What is the fate of erosions in early rheumatoid arthritis? Tracking individual lesions using x rays and magnetic resonance imaging over the first two years of disease

OBJECTIVES

To investigate the progression of erosions at sites within the carpus, in patients with early rheumatoid arthritis (RA), using magnetic resonance imaging (MRI) and plain radiology over a two year period.

METHODS

Gadolinium enhanced MRI scans of the dominant wrist were performed in 42 patients with RA at baseline (within six months of symptom onset) and one year. Plain wrist radiographs (x rays) and clinical data were obtained at baseline, one year, and two years. Erosions were scored by two musculoskeletal radiologists on MRI and x ray at 15 sites in the wrist. A patient centred analysis was used to evaluate the prognostic value of a baseline MRI scan. A lesion centred analysis was used to track the progression of individual erosions over two years.

RESULTS

The baseline MRI erosion score was predictive of x ray erosion score at two years (p=0.004). Patients with a "total MRI score" (erosion, bone oedema, synovitis, and tendonitis) > or =13 at baseline were significantly more likely to develop erosions on x ray at two years (odds ratio 13.4, 95% CI 2.65 to 60.5, p=0.002). Baseline wrist MRI has a sensitivity of 80%, a specificity of 76%, a positive predictive value of 67%, and a high negative predictive value of 86% for the prediction of wrist x ray erosions at two years. A lesion centred analysis, which included erosions scored by one or both radiologists, showed that 84% of baseline MRI erosions were still present at one year. When a more stringent analysis was used which required complete concordance between radiologists, all baseline lesions persisted at one year. The number of MRI erosion sites in each patient increased from 2.1 (SD 2.7) to 5.0 (4.6) (p<0.0001) over the first year of disease. When MRI erosion sites were tracked, 21% and 26% were observed on x ray, one and two years later. A high baseline MRI synovitis score, Ritchie score, and erythrocyte sedimentation rate were predictive of progression of MRI erosions to x ray erosions over one year (p=0.005, 0.01, and 0.03 respectively), but there was no association with the shared epitope. Progression of MRI erosions to x ray erosions was not seen in those with transient polyarthritis.

CONCLUSIONS

MRI scans of the wrist, taken when patients first present with RA, can predict radiographic erosions at two years. MRI may have a role in the assessment of disease prognosis and selection of patients for more or less aggressive treatment. However, only one in four MRI erosions progresses to an x ray erosion over one year, possibly owing to healing, observer error, or technical limitations of radiography at the carpus. Progression of MRI erosions to x ray erosions is greatest in those with high baseline disease activity.

Monotreme IGF2 expression and ancestral origin of genomic imprinting

IGF2 (insulin-like growth factor 2) and M6P/IGF2R (mannose 6-phosphate/insulin-like growth factor 2 receptor) are imprinted in marsupials and eutherians but not in birds. These results along with the absence of M6P/IGF2R imprinting in the egg-laying monotremes indicate that the parental imprinting of fetal growth-regulatory genes may be unique to viviparous mammals. In this investigation, we have cloned IGF2 from two monotreme mammals, the platypus and echidna, to further investigate the origin of imprinting. We report herein that like M6P/IGF2R, IGF2 is not imprinted in monotremes. Thus, although IGF2 encodes for a highly conserved growth factor in chordates, it is only imprinted in therian mammals. These findings support a concurrent origin of IGF2 and M6P/IGF2R imprinting in the late Jurassic/early Cretaceous period. The absence of imprinting in monotremes, despite apparent interparental conflicts over maternal-offspring exchange, argues that a fortuitous congruency of genetic and epigenetic events may have limited the phylogenetic breadth of genomic imprinting to therian mammals. J. Exp. Zool. (Mol. Dev. Evol.) 291:205-212, 2001.

Marsupials and Eutherians reunited: genetic evidence for the Theria hypothesis of mammalian evolution

The three living monophyletic divisions of Class Mammalia are the Prototheria (monotremes), Metatheria (marsupials), and Eutheria ('placental' mammals). Determining the sister relationships among these three groups is the most fundamental question in mammalian evolution. Phylogenetic comparison of these mammals by either anatomy or mitochondrial DNA has resulted in two conflicting hypotheses, Theria and Marsupionta, and has fueled a "genes versus morphology" controversy. We have cloned and analyzed a large nuclear gene, the mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R), from representatives of all three mammalian groups, including platypus, echidna, opossum, wallaby, hedgehog, mouse, rat, rabbit, cow, pig, bat, tree shrew, colugo, ringtail lemur, and human. Statistical analysis of this nuclear gene unambiguously supports the morphology-based Theria hypothesis that excludes monotremes from a clade of marsupials and eutherians. The M6P/IGF2R was also able to resolve the finer structure of the eutherian mammalian family tree. In particular, our analyses support sister group relationships between lagomorphs and rodents, and between the primates and Dermoptera. Statistical support for the grouping of the hedgehog with Feruungulata and Chiroptera was also strong.

Magnetic resonance imaging in rheumatoid arthritis: summary of OMERACT activities, current status, and plans

Complementing the 3 papers that precede it, this paper explains the rationale for the activities of an OMERACT working party on magnetic resonance imaging (MRI) evaluation of rheumatoid arthritis (RA), sets out provisional recommendations for the acquisition and scoring of MRI of the hand and wrist in RA, and delineates some of the many residual problems that need to be addressed.

Interreader agreement in the assessment of magnetic resonance images of rheumatoid arthritis wrist and finger joints--an international multicenter study

Magnetic resonance imaging (MRI) allows direct visualization of inflammation and destruction in rheumatoid arthritis (RA) joints. However, MRI scoring methods have not yet been standardized or appropriately validated. Our aim was to examine interreader agreement for a simple system of scoring RA changes on MRI among 5 centers that had not undertaken intergroup calibration. MRI of RA wrist and metacarpophalangeal (MCP) joints were scored by experienced readers in 5 centers in different countries. In substudy 1, 5 sets of 2nd-5th MCP joints from UK [Technique A: 1.5 T, coronal and axial T1 and T2 spin-echo, -/+ fat saturation (FS), -/+ iv gadolinium (Gd)] were scored for synovitis (score 0-3) and bone lesions (0-3). In substudy 2, we evaluated 19 sets of 2nd-5th MCP joints [10 sets from UK (Technique A) and 9 sets from the US (Technique B: 1.5 T; coronal T1 spin-echo and T2* gradient-echo + FS, no Gd)] and 19 wrist joints [9 from the US (Technique B) and 10 from Denmark (Technique C: 1.0 T; coronal and axial T1 spin-echo, no FS, -/+ Gd)]. Synovitis (0-3), bone lesions (0-3), and joint space narrowing (JSN, 0-3) were scored in each MCP joint and in 3 different regions of the wrist. Bone erosions and lesions in each bone were scored 0-5. Substudy 1 served to test and redesign the score sheets. In substudy 2, the scores of synovitis and bone lesions by the 5 groups were the same or differed by only one grade in 73% and 85% of joints, respectively. On MRI that included 2 imaging planes and iv Gd (Techniques A and C), these rates were 86% (synovitis) and 97% (bone lesions). Corresponding intraclass correlation coefficients (quadratic weighted kappas) were 0.44-0.68, mean 0.58 (synovitis), and 0.44-0.69, mean 0.62 (bone lesion), i.e., in the moderate to good range. Unweighted kappa values were in the low to moderate range, generally lowest for JSN (< 0.20), better for synovitis and bone erosions, and best for bone lesions, being generally highest for MRI with 2 planes pre- and post-Gd and in MCPjoints compared with wrists. These preliminary results suggest that the basic interpretation of MRI changes in RA wrist and MCP joints is relatively consistent among readers from different countries and medical backgrounds, but that further training, calibration, and standardization of imaging protocols and grading schemes will be necessary to achieve acceptable intergroup reproducibility in assessing synovitis and bone destruction in RA multicenter studies.

Magnetic resonance findings in knee dislocation: pictorial essay

Magnetic resonance images depicting the range of soft-tissue and bony injuries associated with knee dislocation are presented. Those injuries that are less well described or more difficult to diagnose are emphasized.

Tests of the ratio rule in categorization

Many theories of learning and memory (e.g., connectionist, associative, rational, exemplar based) produce psychological magnitude terms as output (i.e., numbers representing the momentary level of some subjective property). Many theories assume that these numbers may be translated into choice probabilities via the ratio rule, also known as the choice axiom (Luce, 1959) or the constant-ratio rule (Clarke, 1957). We present two categorization experiments employing artificial, visual, prototype-structured stimuli constructed from 12 symbols positioned on a grid. The ratio rule is shown to be incorrect for these experiments, given the assumption that the magnitude terms for each category are univariate functions of the number of category-appropriate symbols contained in the presented stimulus. A connectionist winner-take-all model of categorical decision (Wills & McLaren, 1997) is shown to account for our data given the same assumption. The central feature underlying the success of this model is the assumption that categorical decisions are based on a Thurstonian choice process (Thurstone, 1927, Case V) whose noise distribution is not double exponential in form.

A 1-year follow-up study of dynamic magnetic resonance imaging in early rheumatoid arthritis reveals synovitis to be increased in shared epitope-positive patients and predictive of erosions at 1 year

OBJECTIVES

Dynamic magnetic resonance imaging (MRI) allows visualization of the synovial membrane and measurement of synovitis within the joint. A cohort of patients with early rheumatoid arthritis (RA) were studied using MRI of the dominant wrist and clinical assessments. Associations between synovitis and the shared epitope genotype (SE) were looked for and synovitis as a predictor of joint erosion was examined.

METHODS

Gadolinium-enhanced MRI scans of the dominant wrist were performed in 42 early RA patients at baseline (median disease duration = 4 months) and after 1 yr. Images were obtained at 42-s intervals over the first 6 min after gadolinium-diethylenetriamine pentaacetic acid injection using six cuts in the coronal plane, 2 mm apart. The site of maximal synovial enhancement was selected as the region of interest (ROI). The rate of enhancement (E-rate) was calculated and compared with synovitis scores from static MRI scans, clinical disease activity scores and HLA-DRB1*04/01 genotyping [sequence-specific primer polymerase chain reaction (SSP-PCR) and DNA sequencing].

RESULTS

Reproducibility of the E-rate measurement was assessed by re-evaluating 10 randomly selected scans in a blinded fashion. Intra-observer reliability was high with an intraclass correlation coefficient of 0.91, 95% confidence interval (CI) 0.65-0.97. The E-rate correlated strongly at baseline with the maximum level of synovial enhancement (E-max) (r = 0.88, P < 0.0001) and the static MRI synovitis score (r = 0.52, P = 0.0004). There was also a weaker but significant correlation between E-rate and the pain score (r = 0.29, P = 0.04). The E-rate fell from baseline to 1 yr (P = 0.02) concordant with clinical improvement after treatment with standard therapies. E-rate scores were higher in SE+ than SE - patients (F(1,25) = 5.19, P = 0.03) and were predictive of MRI erosions at 1 yr [chi-square = 5.0 (1 d.f.), P = 0.03]. The baseline C-reactive protein (CRP) was also predictive of MRI erosions at 1 yr to a similar degree [chi-square = 4.7 (1 d.f. ), P = 0.03] but the mean static synovitis score at baseline was the strongest predictor [chi-square = 9.2 (1 d.f.), P = 0.003].

CONCLUSIONS

These results show that dynamic MRI can be used to score synovitis objectively in early RA patients. Synovitis was greater in SE+ patients, suggesting an early genetic influence on joint inflammation, and was predictive for the development of erosions at 1 yr.