Haem peroxidase activity in Daphnia magna: A biomarker for sub-lethal toxicity assessments of kerosene-contaminated groundwater

A novel biomarker was developed in Daphnia magna to detect organic pollution in groundwater. The haem peroxidase assay, which is an indirect means of measuring oxidase activity, was particularly sensitive to kerosene contamination. Exposure to sub-lethal concentrations of kerosene-contaminated groundwater resulted in a haem peroxidase activity increase by dose with a two-fold activity peak at 25%. Reproduction in D. magna remained unimpaired when exposed to concentrations below 25% for 21 days, and a decline in fecundity was only observed at concentrations above the peak in enzyme activity. The measurement of haem peroxidase activity in D. magna detected sublethal effects of kerosene in just 24 h, whilst offering information on the health status of the organisms. The biomarker may be useful in determining concentrations above which detrimental effects would occur from long-term exposure for fuel hydrocarbons. Moreover, this novel assay detects exposure to chemicals in samples that would normally be classified as non-toxic by acute toxicity tests.

Special educational needs across two decades: survey evidence from English primary schools

The article considers the perceived prevalence of special educational needs in English primary schools and changes in this prevalence over two decades and relates these to issues in education policy, teacher practice and the concept of special educational needs. The studies considered are two major surveys of schools and teachers, the first conducted in 1981 and the second conducted in the same schools in 1998. Important features of both studies were their scale and the exceptionally high response rates achieved. Two central findings were the perception of teachers that special educational needs were widespread and of an increase in special educational needs over time: perceived levels of special educational needs were one in five children in 1981, which had risen to one in four children in 1998. Learning difficulties were by far the most common aspects of special educational needs but many children had multiple difficulties, and behavioural difficulties were seen by teachers as the main barriers to inclusion. The very high figures for prevalence raise questions about the continued usefulness of the concept of special educational need distinct from broader issues of achievement.

Molecular characterisation of the gut microflora of healthy and inflammatory bowel disease cats using fluorescence in situ hybridisation with special reference to Desulfovibrio spp

Inflammatory bowel disease (IBD) is a common cause of chronic large bowel diarrhoea in cats. Although the aetiology of IBD is unknown, an immune-mediated response to a luminal antigen is thought to be involved. As knowledge concerning the colonic microflora of cats is limited and requires further investigation, the purpose of this study was to determine the presence of specific bacterial groups in normal and IBD cats, and the potential role they play in the health of the host. Total bacterial populations, Bacteroides spp., Bifidobacterium spp., Clostridium histolyticum subgp., Lactobacillus-Enterococcus subgp. and Desulfovibrio spp. were enumerated in 34 healthy cats and 11 IBD cats using fluorescence in situ hybridisation. The study is one of the first to show the presence of Desulfovibrio in cats. Total bacteria, Bifidobacterium spp. and Bacteroides spp. counts were all significantly higher in healthy cats when compared with IBD cats, whereas Desulfovibrio spp. (producers of toxic sulphides) numbers were found to be significantly higher in colitic cats. The information obtained from this study suggests that modulation of bacterial flora by increasing bifidobacteria and decreasing Desulfovibrio spp. may be beneficial to cats with IBD. Dietary intervention may be an important aspect of their treatment.

Efficacy of three screening instruments in the identification of autistic-spectrum disorders

Background Screening instruments for autistic-spectrum disorders have not been compared in the same sample. Aims To compare the Social Communication Questionnaire (SCQ), the Social Responsiveness Scale (SRS) and the Children's Communication Checklist (CCC). Method Screen and diagnostic assessments on 119 children between 9 and 13 years of age with special educational needs with and without autistic-spectrum disorders were weighted to estimate screen characteristics for a realistic target population. Results The SCQ performed best (area under receiver operating characteristic curve (AUC)=0.90; sensitivity. 6; specificity 0.78). The SRS had a lower AUC (0.77) with high sensitivity (0.78) and moderate specificity (0.67). The CCC had a high sensitivity but lower specificity (AUC=0.79; sensitivity 0.93; specificity 0.46). The AUC of the SRS and CCC was lower for children with IQ < 70. Behaviour problems reduced specificity for all three instruments. Conclusions The SCQ, SRS and CCC showed strong to moderate ability to identify autistic-spectrum disorder in this at-risk sample of school-age children with special educational needs.

Validation of the social communication questionnaire in a population cohort of children with autism spectrum disorders

Objective: To examine the properties of the Social Communication Questionnaire (SCQ) in a population cohort of children with autism spectrum disorders (ASDs) and in the general population, Method: SCQ data were collected from three samples: the Special Needs and Autism Project (SNAP) cohort of 9- to 10-year-old children with special educational needs with and without ASD and two similar but separate age groups of children from the general population (n = 411 and n = 247). Diagnostic assessments were completed on a stratified subsample (n = 255) of the special educational needs group. A sample-weighting procedure enabled us to estimate characteristics of the SCQ in the total ASD population. Diagnostic status of cases in the general population samples were extracted from child health records. Results: The SCQ showed strong discrimination between ASD and non-ASD cases (sensitivity 0.88, specificity 0.72) and between autism and nonautism cases (sensitivity 0.90, specificity 0.86). Findings were not affected by child IQ or parental education. In the general population samples between 4% and 5% of children scored above the ASD cutoff including 1.5% who scored above the autism cutoff. Although many of these high-scoring children had an ASD diagnosis, almost all (similar to 90%) of them had a diagnosed neurodevelopmental disorder. Conclusions: This study confirms the utility of the SCQ as a,first-level screen for ASD in at-risk samples of school-age children.