Review and quantitative meta-analysis of diet suggests the Eurasian otter (Lutra lutra) is likely to be a poor bioindicator

The Eurasian otter (Lutra lutra L.) is a top predator in aquatic systems and plays an important role in ecosystem functioning. However, it has undergone dramatic declines throughout Europe as a result of environmental degradation. We examine the putative role of the otter as a bioindicator in Ireland which remains a stronghold for the species and affords a unique opportunity to examine variation in its ecological niche. We describe diet, using spraint contents, along rivers during 2010 and conduct a review and quantitative meta-analysis of the results of a further 21 studies. We aimed to assess variation in otter diet in relation to river productivity, a proxy for natural nutrification and anthropogenic eutrophication, and availability of salmonid prey (Salmo trutta and Salmo salar), to test the hypothesis that otter diet is related to environmental quality. Otter diet did not vary with levels of productivity or availability of salmonids whilst Compositional Analysis suggested there was no selection of salmonid over non-salmonid fish. There was a distinct niche separation between riverine and lacustrine systems, the latter being dominated by Atlantic eel (Anguilla anguilla). Otters are opportunistic and may take insects, freshwater mussels, birds, mammals and even fruit. Otters living along coasts have a greatest niche breath than those in freshwater systems which encompasses a wide variety of intertidal prey though pelagic fish are rarely taken. It is concluded that the ability of the otter to feed on a wide diversity of prey taxa and the strong influence of habitat type, renders it a poor bioindicator of environmental water quality. It seems likely that the plasticity of the habitat and dietary niche of otters, and the extent of suitable habitat, may have sustained populations in Ireland despite intensification of agriculture during the 20th century.

Impact of counselling on quality of life and sleep in cancer patients

It has been acknowledged that poor quality of sleep significantly correlates with poor quality of life; evidence suggests that counselling has a positive impact not only on the cancer patient's quality of life, but also on family members and friends. The aim of this service evaluation was to determine if there was an improvement in clients’ quality of life and sleep patterns following counselling as offered by a local cancer charity. A total of 60 matched pre- and post-counselling questionnaires were completed and subjected to statistical analysis. When considering quality of life, in the domains of Role Emotional, Mental Health and Mental Component Summary Score, it can be concluded that counselling has a positive effect on emotional health and mental wellbeing. The mean total number of hours sleep per night significantly increased from 6 hours sleep per night at baseline to 6.8 hours sleep per night at the completion of counselling (p=0.005) showing clients gained an extra 48 minutes sleep per night. The improved emotional and mental wellbeing alongside the extra 48 minutes sleep per night provides evidence that there is a positive outcome for those patients and families who use counselling services. Nurses and other members of the multidisciplinary team should be encouraged to discuss supportive therapies with patients and those affected by cancer at all stages of the cancer trajectory, regardless of social status, gender or cancer type.

Exclusion of linkage between schizophrenia and the D2 dopamine receptor gene region of chromosome 11q in 112 Irish multiplex families

A leading theory hypothesizes that schizophrenia arises from dysregulation of the dopamine system in certain brain regions. As this dysregulation could arise from abnormal expression of D2 dopamine receptors, the D2 receptor gene (DRD2) on chromosome 11q is a candidate locus for schizophrenia. We tested whether allelic variation at DRD2 and five surrounding loci cosegregated with schizophrenia in 112 small- to moderate-size Irish families containing two or more members affected with schizophrenia or schizoaffective disorder, defined by DSM-III-R. Evidence of linkage was assessed using varying definitions of illness and modes of transmission. Assuming genetic homogeneity, linkage between schizophrenia and large regions of 11q around DRD2 could be strongly excluded. Assuming genetic heterogeneity, variation at the DRD2 locus could be rejected as a major risk factor for schizophrenia in more than 50% of these families for all models tested and in as few as 25% of the families for certain models. The DRD2 linkage in fewer than 25% of these families could not be excluded under any of the models tested. Our results suggest that the major component of genetic susceptibility to schizophrenia is not due to allelic variation at the DRD2 locus or other genes in the surrounding chromosomal region.

Evidence for a schizophrenia vulnerability locus on chromosome 8p in the Irish Study of High-Density Schizophrenia Families

This study was an attempt to replicate evidence for a vulnerability locus for schizophrenia and associated disorders in the 8p22-21 region reported by Pulver and colleagues.

Resemblance of psychotic symptoms and syndromes in affected sibling pairs from the Irish Study of High-Density Schizophrenia Families:evidence for possible etiologic heterogeneity

The authors sought to determine whether the clinical manifestations of schizophrenia and other psychotic disorders are correlated in affected sibling pairs.

Support for a possible schizophrenia vulnerability locus in region 5q22-31 in Irish families

In our genome scan for schizophrenia genes in 265 Irish pedigrees, marker D5S818 in 5q22 produced the second best result of the first 223 markers tested (P = 0.002). We then tested an additional 13 markers and the evidence suggests the presence of a vulnerability locus for schizophrenia in region 5q22-31. This region appears to be distinct from those chromosome 5 regions studied in two prior reports, but the same as that producing positive results in the report by Wildenauer and colleagues found elsewhere in this issue. The largest pairwise heterogeneity LOD (H-LOD) score was found with marker D5S393 (max 3.04, P = 0.0005), assuming a narrow phenotypic category, and a genetic model with intermediate heterozygotic liability. In marked contrast to the H-LOD scores from our sample with markers from the regions of interest on chromosomes 6p and 8p, expanding the disease definition to include schizophrenia spectrum or nonspectrum disorders produced substantially smaller scores, with a number of markers failing to yield positive values at any recombination fraction. Using multipoint H-LODS, the strongest evidence for linkage occurs under the narrow phenotypic definition and recessive genetic model, with a peak at marker D5S804 (max 3.35, P = 0.0002). Multipoint nonparametric linkage analysis produced a peak in the same location (max z = 2.84, P = 0.002) with the narrow phenotypic definition. This putative vulnerability locus appears to be segregating in 10-25% of the families studied, but this estimate is tentative. Comparison of individual family multipoint H-LOD scores at the regions of interest on chromosomes 6p, 8p and 5q showed that only a minority of families yield high lod scores in two or three regions.

Clinical features of schizophrenia and linkage to chromosomes 5q, 6p, 8p, and 10p in the Irish Study of High-Density Schizophrenia Families

Schizophrenia is clinically heterogeneous. Recent linkage studies suggest that multiple genes are important in the etiology of schizophrenia. The authors examined the hypothesis of whether the clinical variability in schizophrenia is due to genetic heterogeneity.

Sibling correlation of deficit syndrome in the Irish study of high-density schizophrenia families

The deficit syndrome is a subtype of schizophrenia characterized by primary and enduring negative features of psychopathology. It appears to reflect a distinct subtype within the syndrome of schizophrenia. Little is known about the familial or genetic aspects of the deficit syndrome. The purpose of this study was to determine whether deficit versus nondeficit subtypes are correlated in sibling pairs affected with schizophrenia.

Analysis of epistasis in linked regions in the Irish study of high-density schizophrenia families

Epistasis may be important in the etiology of schizophrenia. Analysis of epistasis has been important in the positional cloning of a gene involved in the etiology of type II diabetes mellitus. We investigated the importance of epistasis among six linked regions in 268 multiplex pedigrees in the Irish Study of High-Density Schizophrenia Families (ISHDSF) by computing pairwise correlations between nonparametric linkage scores for narrow, intermediate, and broad diagnostic definitions. The linked regions were on chromosomes 2, 4, 5, 6, 8, and 10. No correlation reached our a priori level of statistical significance. Using this statistical approach, we did not find evidence of important epistatic effects among these six regions in the ISHDSF.

Genome-wide scans of three independent sets of 90 Irish multiplex schizophrenia families and follow-up of selected regions in all families provides evidence for multiple susceptibility genes

From our linkage study of Irish families with a high density of schizophrenia, we have previously reported evidence for susceptibility genes in regions 5q21-31, 6p24-21, 8p22-21, and 10p15-p11. In this report, we describe the cumulative results from independent genome scans of three a priori random subsets of 90 families each, and from multipoint analysis of all 270 families in ten regions. Of these ten regions, three (13q32, 18p11-q11, and 18q22-23) did not generate scores above the empirical baseline pairwise scan results, and one (6q13-26) generated a weak signal. Six other regions produced more positive pairwise and multipoint results. They showed the following maximum multipoint H-LOD (heterogeneity LOD) and NPL scores: 2p14-13: 0.89 (P = 0.06) and 2.08 (P = 0.02), 4q24-32: 1.84 (P = 0.007) and 1.67 (P = 0.03), 5q21-31: 2.88 (P= 0.0007), and 2.65 (P = 0.002), 6p25-24: 2.13 (P = 0.005) and 3.59 (P = 0.0005), 6p23: 2.42 (P = 0.001) and 3.07 (P = 0.001), 8p22-21: 1.57 (P = 0.01) and 2.56 (P = 0.005), 10p15-11: 2.04 (P = 0.005) and 1.78 (P = 0.03). The degree of 'internal replication' across subsets differed, with 5q, 6p, and 8p being most consistent and 2p and 10p being least consistent. On 6p, the data suggested the presence of two susceptibility genes, in 6p25-24 and 6p23-22. Very few families were positive on more than one region, and little correlation between regions was evident, suggesting substantial locus heterogeneity. The levels of statistical significance were modest, as expected from loci contributing to complex traits. However, our internal replications, when considered along with the positive results obtained in multiple other samples, suggests that most of these six regions are likely to contain genes that influence liability to schizophrenia.

Identification of a high-risk haplotype for the dystrobrevin binding protein 1 (DTNBP1) gene in the Irish study of high-density schizophrenia families

A recent report showed significant associations between several SNPs in a previously unknown EST cluster with schizophrenia. (1). The cluster was identified as the human dystrobrevin binding protein 1 gene (DTNBP1) by sequence database comparisons and homology with mouse DTNBP1. (2). However, the linkage disequilibrium (LD) among the SNPs in DTNBP1 as well as the pattern of significant SNP-schizophrenia association was complex. This raised several questions such as the number of susceptibility alleles that may be involved and the size of the region where the actual disease mutation(s) could be located. To address these questions, we performed different single-marker tests on the 12 previously studied and 2 new SNPs in DTNBP1 that were re-scored using an improved procedure, and performed a variety of haplotype analyses. The sample consisted of 268 Irish multiplex families selected for high density of schizophrenia. Results suggested a simple structure where the LD in the target region could be explained by 6 haplotypes that together accounted for 96% of haplotype diversity in the whole sample. From these six, a single high-risk haplotype was identified that showed a significant association with schizophrenia and explained the pattern of significant findings in the analyses with individual markers. This haplotype was 30 kb long, had a large effect, could be measured with two tag SNPs only, had a frequency of 6% in our sample, seemed to be of relatively recent origin in evolutionary terms, and was equally distributed over Ireland. Implications of these findings for follow-up and replication studies are discussed.