Circulating and synovial antibody profiling of juvenile arthritis patients by nucleic acid programmable protein arrays.

Introduction Juvenile idiopathic arthritis (JIA) is a heterogeneous disease characterized by chronic joint inflammation of unknown cause in children. JIA is an autoimmune disease and small numbers of auto-antibodies have been reported in JIA patients. The identification of antibody markers could improve the existing clinical management of patients. Methods A pilot study was performed on the application of a high-throughput platform, nucleic acid programmable protein arrays (NAPPA), to assess the levels of antibodies present in the systemic circulation and synovial joint of a small cohort of juvenile arthritis patients. Plasma and synovial fluid from ten JIA patients was screened for antibodies against 768 proteins on NAPPA. Results Quantitative reproducibility of NAPPA was demonstrated with >0.95 intra- and inter- array correlations. A strong correlation was also observed for the levels of antibodies between plasma and synovial fluid across the study cohort (r=0.96). Differences in the levels of 18 antibodies were revealed between sample types across all patients. Patients were segregated into two clinical subtypes with distinct antibody signatures by unsupervised hierarchical cluster analysis. Conclusions NAPPA provides a high-throughput quantitatively reproducible platform to screen for disease specific autoantibodies at the proteome level on a microscope slide. The strong correlation between the circulating antibody levels and those of the inflamed joint represents a novel finding and provides confidence to use plasma for discovery of autoantibodies in JIA, thus circumventing the challenges associated with joint aspiration. We expect that autoantibody profiling of JIA patients on NAPPA could yield antibody markers that can act as criteria to stratify patients, predict outcomes and understand disease etiology at the molecular level.

Structural brain abnormalities in male schizophrenics reflect fronto-temporal dissociation

Background. Many studies have separately reported abnormalities of frontal and temporal lobe structures in schizophrenia, but little is known of structural fronto-temporal associations in this condition. We investigated whether male patients with chronic schizophrenia would show abnormal patterns of correlation between regional brain volumes.

Methods. Structural magnetic resonance images of the brain in 42 patients were compared with 43 matched unaffected controls. We explored the pattern of association between regional brain volumes by correlational analyses, and non-parametrically tested for significance of between-group differences by randomization.

Results. The schizophrenics demonstrated significant volume deficits in several brain regions (left temporal lobe and hippocampus, right dorsolateral prefrontal cortex), and significant volume increases in the ventricular system (third ventricle and left temporal horn of the lateral ventricle). Controls demonstrated large positive correlations (r > 0.4) between prefrontal and temporal lobe regions. By contrast, inter-regional correlations significantly reduced in schizophrenics included those between prefrontal, anterior cingulate and temporal regions, and between posterior cingulate and hippocampus (P < 0.05). The most salient abnormality in patients was a dissociation between prefrontal and superior temporal gyrus volumes (P < 0.01).

Conclusions. These results support the existence of a relative 'fronto-temporal dissociation' in schizophrenia which we suggest may be due to lack of mutually trophic influences during frontal and temporal lobe development.

Corpus callosum size and inter-hemispheric function in schizophrenia

We studied the relationship between corpus callosum area and both inter-hemispheric facilitation and interference in schizophrenics and controls. Mid-sagittal sections through the corpus callosum were measured using structural magnetic resonance imaging on 42 patients and 43 normal controls, along with symptom profiles. In a sub-sample, a modified version of the Stroop Test was also performed (27 patients and 29 controls) to assess inter-hemispheric facilitation and interference of colour naming. In the larger sample (total subjects, n=85), there were no significant differences between patients and controls in CC area but a trend towards smaller values in patients in all but the posterior segment. In the sub-sample, bilateral facilitation was greater, and interference, less in schizophrenics compared with controls. There was a positive correlation between facilitation and posterior CC area, parallelled by a negative correlation between interference and posterior CC area, in both patients and controls, which only reached statistical significance when both groups were combined. These findings suggest that the link, between CC size and neuropsychological processes involving inter-hemispheric transfer of information, is common to both schizophrenics and normal controls. There were significant negative correlations between anterior CC area and psychomotor poverty (avolition, anhedonia and affective flattening), and a suggestion that the negative correlation between age and CC size in controls was not present in patients.

Predation in the marine intertidal amphipod Echinogammarus marinus Leach: implications of inter- and intra-individual variation

Studies of competition, predator–prey dynamics and food webs typically consider conspecifics as equal, however, individuals from the same population that are seemingly identical can show considerable variation with regards to a number of processes. Such phenomena may be demonstrated in terms of diet, and the quantities and types of resources that are consumed are commonly considered. The marine amphipod Echinogammarus marinus, a recently demonstrated predator on intertidal rocky shores, has been shown to consume a wide range of food types but it is unknown how this may vary between individuals. Here, we investigated the variation that occurs both among and within individuals of a population of E. marinus with respect to the mean numbers consumed of a common prey item, the isopod Jaera nordmanni. First, by comparing the length of starvation times, used as a proxy for hunger level, individuals maintained without food for up to 24 h consumed significantly less prey during feeding trials than those starved for 48 h and longer. The degree of inter-individual variation within each starvation period was also found to differ, with greater variation among individuals starved for shorter periods of time than those starved for longer time periods. Secondly, we tested whether individual amphipods tracked over time consumed consistently similar numbers of prey or whether they showed intra-individual variation, and if so, to what degree. We found that the numbers of prey consumed per individual could be predicted in the short-term between consecutive feeding trials, however over the long-term this relationship broke down. These results are discussed with respect to potential physiological and behavioural mechanisms, as well as the implications that such variation may have for stability of prey populations in the field.

The Development and Testing of a New Version of the Cognitive Reflection Test Applying Item Response Theory (IRT)

The cognitive reflection test (CRT) is a short measure of a person's ability to resist intuitive response tendencies and to produce a normatively correct response, which is based on effortful reasoning. Although the CRT is a very popular measure, its psychometric properties have not been extensively investigated. A major limitation of the CRT is the difficulty of the items, which can lead to floor effects in populations other than highly educated adults. The present study aimed at investigating the psychometric properties of the CRT applying item response theory analyses (a two-parameter logistic model) and at developing a new version of the scale (the CRT-long), which is appropriate for participants with both lower and higher levels of cognitive reflection. The results demonstrated the good psychometric properties of the original, as well as the new scale. The validity of the new scale was also assessed by measuring correlations with various indicators of intelligence, numeracy, reasoning and decision-making skills, and thinking dispositions. Moreover, we present evidence for the suitability of the new scale to be used with developmental samples. Finally, by comparing the performance of adolescents and young adults on the CRT and CRT-long, we report the first investigation into the development of cognitive reflection.

Expression of the 67 kDa laminin receptor (67LR) during retinal development: correlations with angiogenesis

Interaction of vascular cells with the laminin component of basement membranes is important for normal cell function. Likewise, abnormal interactions may have a critical role in vascular pathology. It has been previously demonstrated that the 67 kDa laminin receptor (67LR) is expressed at high levels during proliferative retinopathy in a mouse model and in the current study we have examined 67LR in the neonatal mouse to determine if this receptor plays a role in aspects of developmental angiogenesis in the developing murine retina. Groups of C57/BL6 mice were killed at postnatal day P1, P3, P5, P7, P9 and P11 to assess the retinal vasculature. A number of mice were perfused with FITC-dextran and the eyes removed, fixed in 4% paraformaldehyde (PFA) and flat-mounted for confocal scanning laser microscopy. The eyes from the remaining mice were either placed in 4% PFA and embedded in paraffin-wax, or had the neural retina dissected off and total RNA or protein extracted. Immunofluorescence, in situ hybridization, quantitative reverse transcriptase polymerase chain reaction and Western blotting analysis were employed to locate and determine expression levels of 67LR. Both 67LR mRNA and protein expression showed a characteristic bi-phasic expression pattern which correlated with key stages of retinal vascular development in the murine retina. 67LR showed high expression levels at P1 (P < 0.05) (correlating with superficial vascular plexus formation) and at P7 (P < 0.05) (correlating with deep vascular plexus formation). Conversely, 67LR expression was decreased when active angiogenic activity was lowest. Significantly, optical sectioning of retinal flat-mounts revealed high levels of 67LR expression in developing segments of both superficial and deep capillary plexi, a pattern which co-localized strongly with laminin. 67LR is regulated during post-natal development of the retinal vasculature. High levels of 67LR during the two well-defined phases of retinal capillary plexus formation suggests that this receptor may play an important role in retinal angiogenesis.

A possible model of benzimidazole binding to beta-tubulin disclosed by invoking an inter-domain movement.

Although it is well established that benzimidazole (BZMs) compounds exert their therapeutic effects through binding to helminth beta-tubulin and thus disrupting microtubule-based processes in the parasites, the precise location of the benzimidazole-binding site on the beta-tubulin molecule has yet to be determined. In the present study, we have used previous experimental data as cues to help identify this site. Firstly, benzimidazole resistance has been correlated with a phenylalanine-to-tyrosine substitution at position 200 of Haemonchus contortus beta-tubulin isotype-I. Secondly, site-directed mutagenesis studies, using fungi, have shown that other residues in this region of the protein can influence the interaction of benzimidazoles with beta-tubulin. However, the atomic structure of the alphabeta-tubulin dimer shows that residue 200 and the other implicated residues are buried within the protein. This poses the question: how might benzimidazoles interact with these apparently inaccessible residues? In the present study, we present a mechanism by which those residues generally believed to interact with benzimidazoles may become accessible to the drugs. Furthermore, by docking albendazole-sulphoxide into a modelled H. contortus beta-tubulin molecule we offer a structural explanation for how the mutation conferring benzimidazole resistance in nematodes may act, as well as a possible explanation for the species-specificity of benzimidazole anthelmintics.

Pullout test correlations and in-place strength assessment - the European Concrete Frame Building Project

A full-scale, seven-story, reinforced concrete building frame was constructed in-place at the Building Research Establishment's Cardington Laboratory, which encompassed a range of different concrete mixtures and advanced construction techniques. This provided an opportunity to assess in-place nondestructive test methods, namely the pullout test, and more specifically the Danish version, which has been known as the Lok test, on a systematic basis during the construction of the building. It was used in conjunction with both standard and temperature-matched cube specimens to assess its practicality and accuracy under site conditions. Strength correlations were determined using linear and power function regression analysis. Strength predictions from these were found to be in very good agreement with the compressive strengths of temperature-matched cube specimens. When a general correlation is used, however, estimates for compressive strength are likely to have 95% confidence limits of around '20% of the mean value of four results.