A multiomic characterization of the leukemia cell line REH using short- and long-read sequencing

The B-cell acute lymphoblastic leukemia (ALL) cell line REH, with the t(12;21) ETV6::RUNX1 translocation, is known to have a complex karyotype defined by a series of large-scale chromosomal rearrangements. Taken from a 15-yr-old at relapse, the cell line offers a practical model for the study of pediatric B-ALL. In recent years, short- and long-read DNA and RNA sequencing have emerged as a complement to karyotyping techniques in the resolution of structural variants in an oncological context. Here, we explore the integration of long-read PacBio and Oxford Nanopore whole-genome sequencing, IsoSeq RNA sequencing, and short-read Illumina sequencing to create a detailed genomic and transcriptomic characterization of the REH cell line. Whole-genome sequencing clarified the molecular traits of disrupted ALL-associated genes including CDKN2A, PAX5, BTG1, VPREB1, and TBL1XR1, as well as the glucocorticoid receptor NR3C1 Meanwhile, transcriptome sequencing identified seven fusion genes within the genomic breakpoints. Together, our extensive whole-genome investigation makes high-quality open-source data available to the leukemia genomics community.

Comparison of high-throughput single-cell RNA-seq methods for ex vivo drug screening

Functional precision medicine (FPM) aims to optimize patient-specific drug selection based on the unique characteristics of their cancer cells. Recent advancements in high throughput ex vivo drug profiling have accelerated interest in FPM. Here, we present a proof-of-concept study for an integrated experimental system that incorporates ex vivo treatment response with a single-cell gene expression output enabling barcoding of several drug conditions in one single-cell sequencing experiment. We demonstrate this through a proof-of-concept investigation focusing on the glucocorticoid-resistant acute lymphoblastic leukemia (ALL) E/R+ Reh cell line. Three different single-cell transcriptome sequencing (scRNA-seq) approaches were evaluated, each exhibiting high cell recovery and accurate tagging of distinct drug conditions. Notably, our comprehensive analysis revealed variations in library complexity, sensitivity (gene detection), and differential gene expression detection across the methods. Despite these differences, we identified a substantial transcriptional response to fludarabine, a highly relevant drug for treating high-risk ALL, which was consistently recapitulated by all three methods. These findings highlight the potential of our integrated approach for studying drug responses at the single-cell level and emphasize the importance of method selection in scRNA-seq studies. Finally, our data encompassing 27 327 cells are freely available to extend to future scRNA-seq methodological comparisons.

Multimodal Single-Cell Sequencing of B Cells in Primary Sjögren's Syndrome

OBJECTIVE

B cells are important in the pathogenesis of primary Sjögren's syndrome (pSS). Patients positive for Sjögren's syndrome antigen A/Sjögren syndrome antigen B (SSA/SSB) autoantibodies are more prone to systemic disease manifestations and adverse outcomes. We aimed to determine the role of B cell composition, gene expression, and B cell receptor usage in pSS subgroups stratified for SSA/SSB antibodies.

METHODS

Over 230,000 B cells were isolated from peripheral blood of patients with pSS (n = 6 SSA-, n = 8 SSA+ single positive and n = 10 SSA/SSB+ double positive) and four healthy controls and processed for single-cell RNA sequencing (scRNA-seq) and single-cell variable, diversity, and joining (VDJ) gene sequencing (scVDJ-seq).

RESULTS

We show that SSA/SSB+ patients present the highest and lowest proportion of naïve and memory B cells, respectively, and the highest up-regulation of interferon-induced genes across all B cell subtypes. Differential usage of IGHV showed that IGHV1-69 and IGHV4-30-4 were more often used in all pSS subgroups compared with controls. Memory B cells from SSA/SSB+ patients displayed a higher proportion of cells with unmutated VDJ transcripts compared with other pSS patient groups and controls, indicating altered somatic hypermutation processes. Comparison with previous studies revealed heterogeneous clonotype pools, with little overlap in CDR3 sequences. Joint analysis using scRNA-seq and scVDJ-seq data allowed unsupervised stratification of patients with pSS and identified novel parameters that correlated to disease manifestations and antibody status.

CONCLUSION

We describe heterogeneity and molecular characteristics in B cells from patients with pSS, providing clues to intrinsic differences in B cells that affect the phenotype and outcome and allowing stratification of patients with pSS at improved resolution.

Genomic, transcriptomic and epigenomic sequencing data of the B-cell leukemia cell line REH

OBJECTIVES

The aim of this data paper is to describe a collection of 33 genomic, transcriptomic and epigenomic sequencing datasets of the B-cell acute lymphoblastic leukemia (ALL) cell line REH. REH is one of the most frequently used cell lines for functional studies of pediatric ALL, and these data provide a multi-faceted characterization of its molecular features. The datasets described herein, generated with short- and long-read sequencing technologies, can both provide insights into the complex aberrant karyotype of REH, and be used as reference datasets for sequencing data quality assessment or for methods development.

DATA DESCRIPTION

This paper describes 33 datasets corresponding to 867 gigabases of raw sequencing data generated from the REH cell line. These datasets include five different approaches for whole genome sequencing (WGS) on four sequencing platforms, two RNA sequencing (RNA-seq) techniques on two different sequencing platforms, DNA methylation sequencing, and single-cell ATAC-sequencing.

Single-cell transcriptomics delineates the immune cell landscape in equine lower airways and reveals upregulation of FKBP5 in horses with asthma

Equine asthma (EA) is a heterogenous, complex disease, with a significant negative impact on horse welfare and performance. EA and human asthma share fundamental similarities, making EA a useful model for studying the disease. One relevant sample type for investigating chronic lung inflammation is bronchoalveolar lavage fluid (BALF), which provides a snapshot of the immune cells present in the alveolar space. To investigate the immune cell landscape of the respiratory tract in horses with mild-to-moderate equine asthma (mEA) and healthy controls, single-cell RNA sequencing was conducted on equine BALF cells. We characterized the major immune cell populations present in equine BALF, as well as subtypes thereof. Interestingly, the most significantly upregulated gene discovered in cases of mEA was FKBP5, a chaperone protein involved in regulating the activity of the glucocorticoid receptor.

Quantitative Transcriptome Analysis of Purified Equine Mast Cells Identifies a Dominant Mucosal Mast Cell Population with Possible Inflammatory Functions in Airways of Asthmatic Horses

Asthma is a chronic inflammatory airway disease and a serious health problem in horses as well as in humans. In humans and mice, mast cells (MCs) are known to be directly involved in asthma pathology and subtypes of MCs accumulate in different lung and airway compartments. The role and phenotype of MCs in equine asthma has not been well documented, although an accumulation of MCs in bronchoalveolar lavage fluid (BALF) is frequently seen. To characterize the phenotype of airway MCs in equine asthma we here developed a protocol, based on MACS Tyto sorting, resulting in the isolation of 92.9% pure MCs from horse BALF. We then used quantitative transcriptome analyses to determine the gene expression profile of the purified MCs compared with total BALF cells. We found that the MCs exhibited a protease profile typical for the classical mucosal MC subtype, as demonstrated by the expression of tryptase (TPSB2) alone, with no expression of chymase (CMA1) or carboxypeptidase A3 (CPA3). Moreover, the expression of genes involved in antigen presentation and complement activation strongly implicates an inflammatory role for these MCs. This study provides a first insight into the phenotype of equine MCs in BALF and their potential role in the airways of asthmatic horses.

Environmentally induced DNA methylation is inherited across generations in an aquatic keystone species

Transgenerational inheritance of environmentally induced epigenetic marks can have significant impacts on eco-evolutionary dynamics, but the phenomenon remains controversial in ecological model systems. We used whole-genome bisulfite sequencing of individual water fleas (Daphnia magna) to assess whether environmentally induced DNA methylation is transgenerationally inherited. Genetically identical females were exposed to one of three natural stressors, or a de-methylating drug, and their offspring were propagated clonally for four generations under control conditions. We identified between 70 and 225 differentially methylated CpG positions (DMPs) in F1 individuals whose mothers were exposed to a natural stressor. Roughly half of these environmentally induced DMPs persisted until generation F4. In contrast, treatment with the drug demonstrated that pervasive hypomethylation upon exposure is reset almost completely after one generation. These results suggest that environmentally induced DNA methylation is non-random and stably inherited across generations in Daphnia, making epigenetic inheritance a putative factor in the eco-evolutionary dynamics of freshwater communities.

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Naturally induced DNA-methylation persists until generation F4 in Daphnia

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Drug-induced de-methylation is reset after one generation

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Methylation is enriched in exons suggesting a gene regulatory function

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Epigenetic inheritance may influence eco-evolutionary dynamics

The SEQC2 epigenomics quality control (EpiQC) study

BACKGROUND

Cytosine modifications in DNA such as 5-methylcytosine (5mC) underlie a broad range of developmental processes, maintain cellular lineage specification, and can define or stratify types of cancer and other diseases. However, the wide variety of approaches available to interrogate these modifications has created a need for harmonized materials, methods, and rigorous benchmarking to improve genome-wide methylome sequencing applications in clinical and basic research. Here, we present a multi-platform assessment and cross-validated resource for epigenetics research from the FDA's Epigenomics Quality Control Group.

RESULTS

Each sample is processed in multiple replicates by three whole-genome bisulfite sequencing (WGBS) protocols (TruSeq DNA methylation, Accel-NGS MethylSeq, and SPLAT), oxidative bisulfite sequencing (TrueMethyl), enzymatic deamination method (EMSeq), targeted methylation sequencing (Illumina Methyl Capture EPIC), single-molecule long-read nanopore sequencing from Oxford Nanopore Technologies, and 850k Illumina methylation arrays. After rigorous quality assessment and comparison to Illumina EPIC methylation microarrays and testing on a range of algorithms (Bismark, BitmapperBS, bwa-meth, and BitMapperBS), we find overall high concordance between assays, but also differences in efficiency of read mapping, CpG capture, coverage, and platform performance, and variable performance across 26 microarray normalization algorithms.

CONCLUSIONS

The data provided herein can guide the use of these DNA reference materials in epigenomics research, as well as provide best practices for experimental design in future studies. By leveraging seven human cell lines that are designated as publicly available reference materials, these data can be used as a baseline to advance epigenomics research.

Comparison of EM-seq and PBAT methylome library methods for low-input DNA

DNA methylation is the most studied epigenetic mark involved in regulation of gene expression. For low input samples, a limited number of methods for quantifying DNA methylation genome-wide has been evaluated. Here, we compared a series of input DNA amounts (1–10ng) from two methylome library preparation protocols, enzymatic methyl-seq (EM-seq) and post-bisulfite adaptor tagging (PBAT) adapted from single-cell PBAT. EM-seq takes advantage of enzymatic activity while PBAT relies on conventional bisulfite conversion for detection of DNA methylation. We found that both methods accurately quantified DNA methylation genome-wide. They produced expected distribution patterns around genomic features, high C-T transition efficiency at non-CpG sites and high correlation between input amounts. However, EM-seq performed better in regard to library and sequencing quality, i.e. EM-seq produced larger insert sizes, higher alignment rates and higher library complexity with lower duplication rate compared to PBAT. Moreover, EM-seq demonstrated higher CpG coverage, better CpG site overlap and higher consistency between input series. In summary, our data suggests that EM-seq overall performed better than PBAT in whole-genome methylation quantification of low input samples.

Leukocytes with chromosome Y loss have reduced abundance of the cell surface immunoprotein CD99

Mosaic loss of chromosome Y (LOY) in immune cells is a male-specific mutation associated with increased risk for morbidity and mortality. The CD99 gene, positioned in the pseudoautosomal regions of chromosomes X and Y, encodes a cell surface protein essential for several key properties of leukocytes and immune system functions. Here we used CITE-seq for simultaneous quantification of CD99 derived mRNA and cell surface CD99 protein abundance in relation to LOY in single cells. The abundance of CD99 molecules was lower on the surfaces of LOY cells compared with cells without this aneuploidy in all six types of leukocytes studied, while the abundance of CD proteins encoded by genes located on autosomal chromosomes were independent from LOY. These results connect LOY in single cells with immune related cellular properties at the protein level, providing mechanistic insight regarding disease vulnerability in men affected with mosaic chromosome Y loss in blood leukocytes.

Single nucleus transcriptomics data integration recapitulates the major cell types in human liver

AIM

The aim of this study was to explore the benefits of data integration from different platforms for single nucleus transcriptomics profiling to characterize cell populations in human liver.

METHODS

We generated single-nucleus RNA sequencing data from Chromium 10X Genomics and Drop-seq for a human liver sample. We utilized state of the art bioinformatics tools to undertake a rigorous quality control and to integrate the data into a common space summarizing the gene expression variation from the respective platforms, while accounting for known and unknown confounding factors.

RESULTS

Analysis of single nuclei transcriptomes from both 10X and Drop-seq allowed identification of the major liver cell types, while the integrated set obtained enough statistical power to separate a small population of inactive hepatic stellate cells that was not characterized in either of the platforms.

CONCLUSIONS

Integration of droplet-based single nucleus transcriptomics data enabled identification of a small cluster of inactive hepatic stellate cells that highlights the potential of our approach. We suggest single-nucleus RNA sequencing integrative approaches could be utilized to design larger and cost-effective studies.

Deep targeted sequencing in pediatric acute lymphoblastic leukemia unveils distinct mutational patterns between genetic subtypes and novel relapse-associated genes

To characterize the mutational patterns of acute lymphoblastic leukemia (ALL) we performed deep next generation sequencing of 872 cancer genes in 172 diagnostic and 24 relapse samples from 172 pediatric ALL patients. We found an overall greater mutational burden and more driver mutations in T-cell ALL (T-ALL) patients compared to B-cell precursor ALL (BCP-ALL) patients. In addition, the majority of the mutations in T-ALL had occurred in the original leukemic clone, while most of the mutations in BCP-ALL were subclonal. BCP-ALL patients carrying any of the recurrent translocations ETV6-RUNX1, BCR-ABL or TCF3-PBX1 harbored few mutations in driver genes compared to other BCP-ALL patients. Specifically in BCP-ALL, we identified ATRX as a novel putative driver gene and uncovered an association between somatic mutations in the Notch signaling pathway at ALL diagnosis and increased risk of relapse. Furthermore, we identified EP300, ARID1A and SH2B3 as relapse-associated genes. The genes highlighted in our study were frequently involved in epigenetic regulation, associated with germline susceptibility to ALL, and present in minor subclones at diagnosis that became dominant at relapse. We observed a high degree of clonal heterogeneity and evolution between diagnosis and relapse in both BCP-ALL and T-ALL, which could have implications for the treatment efficiency.

Data quality of whole genome bisulfite sequencing on Illumina platforms

The powerful HiSeq X sequencers with their patterned flowcell technology and fast turnaround times are instrumental for many large-scale genomic and epigenomic studies. However, assessment of DNA methylation by sodium bisulfite treatment results in sequencing libraries of low diversity, which may impact data quality and yield. In this report we assess the quality of WGBS data generated on the HiSeq X system in comparison with data generated on the HiSeq 2500 system and the newly released NovaSeq system. We report a systematic issue with low basecall quality scores assigned to guanines in the second read of WGBS when using certain Real Time Analysis (RTA) software versions on the HiSeq X sequencer, reminiscent of an issue that was previously reported with certain HiSeq 2500 software versions. However, with the HD.3.4.0 /RTA 2.7.7 software upgrade for the HiSeq X system, we observed an overall improved quality and yield of the WGBS data generated, which in turn empowers cost-effective and high quality DNA methylation studies.

The structure of schizotypal personality traits: a cross-national study

BACKGROUND

Schizotypal traits are considered a phenotypic-indicator of schizotypy, a latent personality organization reflecting a putative liability for psychosis. To date, no previous study has examined the comparability of factorial structures across samples originating from different countries and cultures. The main goal was to evaluate the factorial structure and reliability of the Schizotypal Personality Questionnaire (SPQ) scores by amalgamating data from studies conducted in 12 countries and across 21 sites.

METHOD

The overall sample consisted of 27 001 participants (37.5% males, n = 4251 drawn from the general population). The mean age was 22.12 years (s.d. = 6.28, range 16-55 years). The SPQ was used. Confirmatory factor analysis (CFA) and Multilevel CFA (ML-CFA) were used to evaluate the factor structure underlying the SPQ scores.

RESULTS

At the SPQ item level, the nine factor and second-order factor models showed adequate goodness-of-fit. At the SPQ subscale level, three- and four-factor models displayed better goodness-of-fit indices than other CFA models. ML-CFA showed that the intraclass correlation coefficients values were lower than 0.106. The three-factor model showed adequate goodness of fit indices in multilevel analysis. The ordinal α coefficients were high, ranging from 0.73 to 0.94 across individual samples, and from 0.84 to 0.91 for the combined sample.

CONCLUSIONS

The results are consistent with the conceptual notion that schizotypal personality is a multifaceted construct and support the validity and utility of SPQ in cross-cultural research. We discuss theoretical and clinical implications of our results for diagnostic systems, psychosis models and cross-national mental health strategies.

Transcriptome sequencing in pediatric acute lymphoblastic leukemia identifies fusion genes associated with distinct DNA methylation profiles

BACKGROUND

Structural chromosomal rearrangements that lead to expressed fusion genes are a hallmark of acute lymphoblastic leukemia (ALL). In this study, we performed transcriptome sequencing of 134 primary ALL patient samples to comprehensively detect fusion transcripts.

METHODS

We combined fusion gene detection with genome-wide DNA methylation analysis, gene expression profiling, and targeted sequencing to determine molecular signatures of emerging ALL subtypes.

RESULTS

We identified 64 unique fusion events distributed among 80 individual patients, of which over 50% have not previously been reported in ALL. Although the majority of the fusion genes were found only in a single patient, we identified several recurrent fusion gene families defined by promiscuous fusion gene partners, such as ETV6, RUNX1, PAX5, and ZNF384, or recurrent fusion genes, such as DUX4-IGH. Our data show that patients harboring these fusion genes displayed characteristic genome-wide DNA methylation and gene expression signatures in addition to distinct patterns in single nucleotide variants and recurrent copy number alterations.

CONCLUSION

Our study delineates the fusion gene landscape in pediatric ALL, including both known and novel fusion genes, and highlights fusion gene families with shared molecular etiologies, which may provide additional information for prognosis and therapeutic options in the future.

SPlinted Ligation Adapter Tagging (SPLAT), a novel library preparation method for whole genome bisulphite sequencing

Sodium bisulphite treatment of DNA combined with next generation sequencing (NGS) is a powerful combination for the interrogation of genome-wide DNA methylation profiles. Library preparation for whole genome bisulphite sequencing (WGBS) is challenging due to side effects of the bisulphite treatment, which leads to extensive DNA damage. Recently, a new generation of methods for bisulphite sequencing library preparation have been devised. They are based on initial bisulphite treatment of the DNA, followed by adaptor tagging of single stranded DNA fragments, and enable WGBS using low quantities of input DNA. In this study, we present a novel approach for quick and cost effective WGBS library preparation that is based on splinted adaptor tagging (SPLAT) of bisulphite-converted single-stranded DNA. Moreover, we validate SPLAT against three commercially available WGBS library preparation techniques, two of which are based on bisulphite treatment prior to adaptor tagging and one is a conventional WGBS method.

DNA methylome analysis of acute lymphoblastic leukemia cells reveals stochastic de novo DNA methylation in CpG islands

AIM

To identify regions of aberrant DNA methylation in acute lymphoblastic leukemia (ALL) cells of different subtypes on a genome-wide scale.

MATERIALS & METHODS

Whole-genome bisulfite sequencing (WGBS) was used to determine the DNA methylation levels in cells from four pediatric ALL patients of different subtypes. The findings were confirmed by 450k DNA methylation arrays in a large patient set.

RESULTS

Compared with mature B or T cells WGBS detected on average 82,000 differentially methylated regions per patient. Differentially methylated regions are enriched to CpG poor regions, active enhancers and transcriptional start sites. We also identified approximately 8000 CpG islands with variable intermediate DNA methylation that seems to occur as a result of stochastic de novo methylation.

CONCLUSION

WGBS provides an unbiased view and novel insights into the DNA methylome of ALL cells.

Histological characterization of orphan transporter MCT14 (SLC16A14) shows abundant expression in mouse CNS and kidney

BACKGROUND

MCT14 (SLC16A14) is an orphan member of the monocarboxylate transporter (MCT) family, also known as the SLC16 family of secondary active transmembrane transporters. Available expression data for this transporter is limited, and in this paper we aim to characterize MCT14 with respect to tissue distribution and cellular localization in mouse brain.

RESULTS

Using qPCR, we found that Slc16a14 mRNA was highly abundant in mouse kidney and moderately in central nervous system, testis, uterus and liver. Using immunohistochemistry and in situ hybridization, we determined that MCT14 was highly expressed in excitatory and inhibitory neurons as well as epithelial cells in the mouse brain. The expression was exclusively localized to the soma of neurons. Furthermore, we showed with our phylogenetic analysis that MCT14 most closely relate to the aromatic amino acid- and thyroid-hormone transporters MCT8 (SLC16A2) and MCT10 (SLC16A10), in addition to the carnitine transporter MCT9 (SLC16A9).

CONCLUSIONS

We provide here the first histological mapping of MCT14 in the brain and our data are consistent with the hypothesis that MCT14 is a neuronal aromatic-amino-acid transporter.

Neural mediator of the schizotypy-antisocial behavior relationship

Prior studies have established that schizotypal personality traits (schizotypy) were associated with antisocial behavior (crime), but it is unclear what neural factors mediate this relationship. This study assessed the mediating effect that sub-regional prefrontal gray, specifically the orbitofrontal gray matter volume, has on the schizotypy-antisocial behavior relationship. Five prefrontal sub-regional (superior, middle, inferior, orbitofrontal and rectal gyral) gray matter volumes were assessed using structural magnetic resonance imaging in 90 adults from the community, together with schizotypy and antisocial behavior. Among all five prefrontal sub-regions, the orbitofrontal cortex (OFC) was the major region-of-interest in the present study. Mediation analyses showed that orbitofrontal gray fully mediated the association between schizotypy and antisocial behavior. After having controlled the sex, age, socio-economic statuses, whole brain volumes and substance abuse/dependence of test subjects, the orbitofrontal gray still significantly mediated the effect of schizotypy on antisocial behavior by 53.5%. These findings are the first that document a neural mediator of the schizotypy-antisocial behavior relationship. Findings also suggest that functions subserved by the OFC, including impulse control and inhibition, emotion processing and decision-making, may contribute to the above comorbidity.

The mutational landscape in pediatric acute lymphoblastic leukemia deciphered by whole genome sequencing

Genomic characterization of pediatric acute lymphoblastic leukemia (ALL) has identified distinct patterns of genes and pathways altered in patients with well-defined genetic aberrations. To extend the spectrum of known somatic variants in ALL, we performed whole genome and transcriptome sequencing of three B-cell precursor patients, of which one carried the t(12;21)ETV6-RUNX1 translocation and two lacked a known primary genetic aberration, and one T-ALL patient. We found that each patient had a unique genome, with a combination of well-known and previously undetected genomic aberrations. By targeted sequencing in 168 patients, we identified KMT2D and KIF1B as novel putative driver genes. We also identified a putative regulatory non-coding variant that coincided with overexpression of the growth factor MDK. Our results contribute to an increased understanding of the biological mechanisms that lead to ALL and suggest that regulatory variants may be more important for cancer development than recognized to date. The heterogeneity of the genetic aberrations in ALL renders whole genome sequencing particularly well suited for analysis of somatic variants in both research and diagnostic applications.

A longitudinal biosocial study of cortisol and peer influence on the development of adolescent antisocial behavior

It is increasingly recognized that in order to understand the complex phenomenon of antisocial behavior, interrelations between biological and social risk factors should be taken into account. In the current study, this biosocial approach was applied to examine the mediating role of deviant peers in longitudinal associations linking the level of hypothalamic-pituitary-adrenal (HPA) axis activity to aggression and rule-breaking. Participants were 425 boys and girls from the general population, who were assessed yearly at ages 15, 16, and 17. As a measure of HPA axis activity, cortisol was assessed at awakening, 30, and 60 min later (the cortisol awakening response, CAR). Participants, as well as their best friend, reported on their own aggressive and rule-breaking behavior, thereby allowing to assess bidirectional influences within friendships. Aggression was only predicted by a decreased cortisol level at awakening, and not by aggressive behavior of their friend. Decreased levels of cortisol at awakening predicted adolescents' rule-breaking, which subsequently predicted increased rule-breaking of their best friend. The latter was only found for adolescents who changed friends, as compared to adolescents with the same friend in every year. Gender differences were not found. These findings suggest that interrelations between biological and social risk factors are different for the development of aggression versus rule-breaking. Furthermore, decreased levels of HPA axis activity may represent a susceptibility to selecting deviant peers.

Installation of mechanical ventilation in a horse stable: effects on air quality and human and equine airways

OBJECTIVES

To examine the effects of installing a mechanical ventilation system at a riding-school stable on indoor air quality and human and horse airways.

METHODS

The intervention was the installation of mechanical ventilation in a riding-school stable. Carbon dioxide (CO2), ammonia, particles, horse allergen, microorganisms and endotoxins were measured in the stable. The stable-workers and riding-students completed a questionnaire and underwent the following tests: analysis of nasal lavage for inflammation biomarkers; levels of exhaled nitrogen oxide (NO); measurements of daily peak-expiratory flow (PEF). The horses were examined clinically by airway endoscopy and bronchoalveolar lavage (BAL) and were analysed for cytology and biomarkers.

RESULTS

Levels of CO2 were nearly halved and airborne horse allergen levels were markedly reduced (5-0.8 kU/m3) after the intervention. A decreased level of ultrafine particles was observed (8000-5400 particles/cm3) after the intervention, while total and respirable dust levels were mainly unchanged (200 and 130 μg/m3). Levels of microorganisms in surface samples decreased following the intervention, whereas airborne microorganisms and endotoxin increased. There was no significant change in human symptoms, PEF-variability, exhaled NO or inflammatory biomarkers in the nasal lavage. In horses, the mean score of lower airway mucus was significantly reduced together with the mean level of expression of interleukin-6 mRNA in BAL cells after the intervention.

CONCLUSIONS

The installation of a mechanical ventilation system resulted in an increased air exchange rate, as demonstrated by reduced levels of CO2, ammonia, ultrafine particles and horse allergen. There was no significant clinical effect on human airways, but there was a tendency for reduced inflammation markers. The results on the horses may indicate less impact on their airways after the intervention.

Psychopathic personality in children: genetic and environmental contributions

BACKGROUND

The current study investigates whether the underlying factor structure of psychopathic personality traits found in adults is similar to that in children and what the extent of the genetic and environmental influences are on these psychopathic traits.

METHOD

Psychopathic personality traits were assessed in a community sample of 1219 twins and triplets (age 9-10 years) through caregiver reports of each child's behavior using the Child Psychopathy Scale (CPS).

RESULTS

Confirmatory factor analyses revealed an optimal two-factor solution (callous/disinhibited and manipulative/deceitful) to the CPS subscales. Bivariate genetic modeling of the two computed factor scores revealed significant genetic as well as unique environmental influences on psychopathic personality traits in both boys and girls, with heritability estimates of 0.64 and 0.46, respectively, in boys and 0.49 and 0.58, respectively, in girls. No shared environmental influences on psychopathic personality traits were found.

CONCLUSIONS

The relationship between the two factors was mediated by both genetic and unique environmental factors common to both traits.

H-NS-mediated repression of CRISPR-based immunity in Escherichia coli K12 can be relieved by the transcription activator LeuO

The recently discovered prokaryotic CRISPR/Cas defence system provides immunity against viral infections and plasmid conjugation. It has been demonstrated that in Escherichia coli transcription of the Cascade genes (casABCDE) and to some extent the CRISPR array is repressed by heat-stable nucleoid-structuring (H-NS) protein, a global transcriptional repressor. Here we elaborate on the control of the E. coli CRISPR/Cas system, and study the effect on CRISPR-based anti-viral immunity. Transformation of wild-type E. coli K12 with CRISPR spacers that are complementary to phage Lambda does not lead to detectable protection against Lambda infection. However, when an H-NS mutant of E. coli K12 is transformed with the same anti-Lambda CRISPR, this does result in reduced sensitivity to phage infection. In addition, it is demonstrated that LeuO, a LysR-type transcription factor, binds to two sites flanking the casA promoter and the H-NS nucleation site, resulting in derepression of casABCDE12 transcription. Overexpression of LeuO in E. coli K12 containing an anti-Lambda CRISPR leads to an enhanced protection against phage infection. This study demonstrates that in E. coli H-NS and LeuO are antagonistic regulators of CRISPR-based immunity.

Early maternal and paternal bonding, childhood physical abuse and adult psychopathic personality

BACKGROUND

A significant gap in the literature on risk factors for psychopathy is the relative lack of research on parental bonding.MethodThis study examines the cross-sectional relationship between maternal and paternal bonding, childhood physical abuse and psychopathic personality at age 28 years in a community sample of 333 males and females. It also assesses prospectively whether children separated from their parents in the first 3 years of life are more likely to have a psychopathic-like personality 25 years later.

RESULTS

Hierarchical regression analyses indicated that: (1) poor parental bonding (lack of maternal care and low paternal overprotection) and childhood physical abuse were both associated with a psychopathic personality; (2) parental bonding was significantly associated with psychopathic personality after taking into account sex, social adversity, ethnicity and abuse; (3) those separated from parents in the first 3 years of life were particularly characterized by low parental bonding and a psychopathic personality in adulthood; and (4) the deviant behavior factor of psychopathy was more related to lack of maternal care whereas the emotional detachment factor was related to both lack of maternal care and paternal overprotection.

CONCLUSIONS

Findings draw attention to the importance of different components of early bonding in relation to adult psychopathy, and may have potential implications for early intervention and prevention of psychopathy.

Markers of respiratory inflammation in horses in relation to seasonal changes in air quality in a conventional racing stable

Airborne factors in a conventionally managed racing stable and markers of pulmonary inflammation in the stabled horses were investigated on 3 occasions at 6-month intervals, including 2 winter periods and the intervening summer period. The stable measurements included inside and outside ambient temperature and relative humidity, levels of total and respirable dust, endotoxin, and 1,3-beta-glucan. Horses (n = 12) were examined in detail clinically as well as by endoscopy, bronchoalveolar lavage (BAL) cytology, and real-time polymerase chain reaction (RT-PCR) analysis of BAL-cells for IL-6 and IL-10 mRNA. Indoor measurements showed low dust levels irrespective of season. Inhalable dust, as well as 1,3-beta-glucan, were higher during the winter stabling period, whereas endotoxin levels were higher during summer. Complete data from all sampling occasions to be used for further evaluation was obtained for only 8 of the horses. There was a trend for elevation of BAL neutrophils in the horses during winter stabling that coincided with a 3.7-fold increased expression of IL-6 mRNA in BAL cells (P = 0.014). Compared to summer sampling, IL-10 mRNA expression was significantly upregulated in only 1 of the winter sampling occasions, implicating influence on immune regulation by factor/s apart from seasonal differences. Our findings suggest up-regulation of innate immunity in the airways of stabled horses; in particular involving IL-6 in association with mild elevations in respirable dust, 1,3-beta-glucan, and/or cold ambient air. However, given that this study was observational, other unmeasured environmental factors associated with winter stabling need to be considered.

Epithelial expression of mRNA and protein for IL-6, IL-10 and TNF-alpha in endobronchial biopsies in horses with recurrent airway obstruction

Background

The aim of this study was to evaluate the contribution of bronchial epithelium to airway inflammation, with focus on mRNA and protein expression of cytokines of innate immunity IL-6, IL-10 and TNF-α, in horses with Recurrent Airway Obstruction (RAO) during exacerbation and in remission.

Results

Despite marked clinical and physiologic alterations between exacerbation and after remission in the RAO horses no differences were detected in either cytokine mRNA or protein levels. Moreover, the expression of investigated cytokines in RAO horses on pasture did not differ from controls.

In comparing real-time PCR analysis to results of immunohistochemistry only IL-10 mRNA and protein levels in RAO horses on pasture were significantly correlated (r_s = 0.893, p = 0.007). Curiously, in controls examined on pasture the TNF-α protein level was positively correlated to IL-10 mRNA expression (r_s = 0.967, p = 0.007) and negatively correlated to IL-6 mRNA expression (r_s = -0.971, p = 0.001).

Conclusion

Given the complementary relationship of assessing cytokines directly by immunohistochemistry, or indirectly by PCR to mRNA, the lack of significant changes in either mRNA or protein levels of IL-6, IL-10 or TNF-α mRNA in RAO horses in exacerbation suggests that these particular cytokines in bronchial tissue may not play a substantive role in the active inflammation of this disease. To support this contention further studies examining time dependency of expression of IL-6, IL-10 or TNF-α are needed, as is expansion of the range of cytokines to include other key regulators of airway inflammation.

Partial divergence of cytokine mRNA expression in bronchial tissues compared to bronchoalveolar lavage cells in horses with recurrent airway obstruction

The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA levels in endobronchial biopsies and bronchoalveolar lavage (BAL) cells were compared. Seven RAO horses were examined while in respiratory crisis following provocation and again while in remission after 2 months on pasture, during which time six healthy horses on pasture were also examined. Quantitative real-time PCR (RT-PCR) was used to assess mRNA expression for cytokines IL-5, IL-6, IL-8, IL-10, IL-17 and transforming growth factor beta1 (TGF-beta1) in endobronchial biopsies and bronchoalveolar lavage. Expression of IL-8 mRNA was significantly upregulated during crisis in both endobronchial biopsies and BAL cells (p=0.036), while there was a similar trend for upregulation of IL-10 mRNA only in BAL cells that approached significance (p=0.059). Moreover, during crisis the expression of IL-8 mRNA in BAL cells was positively correlated to relative IL-6 mRNA expression (r(s)=0.971, p=0.001) and bronchial epithelial expression of IL-10 and TGF-beta1 mRNA were positively correlated (r(s)=0.943, p=0.005). In comparing the relationship of mRNA expression in BAL to biopsy in individual RAO horses, there was a positive correlation with IL-6 to IL-8 mRNA expression in BAL during respiratory crisis (r(s)=0.971, p=0.001) that also correlated positively with IL-8 expression in biopsies on pasture (r(s)=0.986, p<0.0001 for both). Regarding RAO horses at pasture versus controls neither the cytokine mRNA levels in endobronchial biopsy nor in BAL cells differed significantly. These results further support previous findings that IL-8 mRNA in both BAL cells and bronchial epithelium is upregulated in RAO horses during crisis. However, apart from IL-8, it appears that expression of other cytokines, including IL-5, IL-6, IL-10, IL-17 and TGF-beta1 in bronchial epithelium does not necessarily mirror cytokine expression in BAL cells in individual horses with RAO. Accordingly, examination of markers of inflammation in endobronchial tissue provides complementary but not necessarily identical information to that obtained in BAL cells. Given the potential for repeated sampling over time bronchial biopsy can serve as an invaluable additional tool for investigation of time-dependent changes in inflammatory process in this animal model of asthma.

Trigger factor binding to ribosomes with nascent peptide chains of varying lengths and sequences

Trigger factor (TF) is the first protein-folding chaperone to interact with a nascent peptide chain as it emerges from the ribosome. Here, we have used a spin down assay to estimate the affinities for the binding of TF to ribosome nascent chain complexes (RNCs) with peptides of varying lengths and sequences. An in vitro system for protein synthesis assembled from purified Escherichia coli components was used to produce RNCs stalled on truncated mRNAs. The affinity of TF to RNCs exposing RNA polymerase sequences increased with the length of the nascent peptides. TF bound to RNA polymerase RNCs with significantly higher affinity than to inner membrane protein leader peptidase and bacterioopsin RNCs. The latter two RNCs are substrates for signal recognition particle, suggesting complementary affinities of TF and signal recognition particle to nascent peptides targeted for cytoplasm and membrane.

Simultaneous binding of trigger factor and signal recognition particle to the E. coli ribosome

Signal recognition particle (SRP) and trigger factor (TF) both bind to ribosomal protein L23 at the peptide exit area on the 50S subunit of the E. coli ribosome. In this study, we have developed a spin-down assay and used it to estimate KD values and the corresponding enthalpies for the binding of radio-labelled SRP and TF to naked ribosomes and to ribosomes carrying a tetrapeptidyl-tRNA in the P site. At 20 degrees C, the KD value for TF binding is 2 microM and for SRP it is 170 nM for naked as well as for translating ribosomes. At 4 degrees C, the KD values for TF and SRP binding are 1.1 microM and 90 nM, respectively. Competition binding experiments reveal that SRP and TF bind simultaneously to the ribosome with little affinity interference, showing that the factors have separate binding sites on L23. This makes an alternating binding mode for TF and SRP less plausible.

Targeting and insertion of heterologous membrane proteins in E. coli

Membrane targeting and insertion of the archaeal Halobacter halobium proton pump bacterioopsin (Bop) and the human melanocortin 4 receptor (MC(4)R) were studied in vitro, using E. coli components for protein synthesis, membrane targeting and insertion. These heterologous proteins are targeted to E. coli membranes in a signal recognition particle (SRP) dependent manner and inserted into the membrane co-translationally. Furthermore, we demonstrate that nascent chains of Bop and MC(4)R first interact with SecY and then with YidC as they move through the translocon. Our results suggest that the initial stages of membrane targeting and insertion of heterologous proteins in E. coli proceed by the pathway used for native E. coli membrane proteins. No significant pausing of protein elongation was observed in the presence of E. coli SRP, in line with the suggestion that translational arrest requires an Alu domain, which is absent in SRP from E. coli.

Interplay of signal recognition particle and trigger factor at L23 near the nascent chain exit site on the Escherichia coli ribosome

As newly synthesized polypeptides emerge from the ribosome, they interact with chaperones and targeting factors that assist in folding and targeting to the proper location in the cell. In Escherichia coli, the chaperone trigger factor (TF) binds to nascent polypeptides early in biosynthesis facilitated by its affinity for the ribosomal proteins L23 and L29 that are situated around the nascent chain exit site on the ribosome. The targeting factor signal recognition particle (SRP) interacts specifically with the signal anchor (SA) sequence in nascent inner membrane proteins (IMPs). Here, we have used photocross-linking to map interactions of the SA sequence in a short, in vitro-synthesized, nascent IMP. Both TF and SRP were found to interact with the SA with partially overlapping binding specificity. In addition, extensive contacts with L23 and L29 were detected. Both purified TF and SRP could be cross-linked to L23 on nontranslating ribosomes with a competitive advantage for SRP. The results suggest a role for L23 in the targeting of IMPs as an attachment site for TF and SRP that is close to the emerging nascent chain.

Temporal lobe deficits in murderers: EEG findings undetected by PET

This study evaluates electroencephalography (EEG) and positron emission tomography (PET) in the same subjects. Fourteen murderers were assessed by using both PET (while they were performing the continuous performance task) and EEG during a resting state. EEG revealed significant increases in slow-wave activity in the temporal, but not frontal, lobe in murderers, in contrast to prior PET findings that showed reduced prefrontal, but not temporal, glucose metabolism. Results suggest that resting EEG shows empirical utility distinct from PET activation findings.

Increased height and bulk in antisocial personality disorder and its subtypes

Research suggests that those with antisocial tendencies are larger than controls, but studies have not assessed this association in antisocial personality disorder (APD) or its hypothesized sub-types (i.e. adolescence-limited, late-onset). Height, weight, body mass index, bulk, and psychosocial adversity were assessed in 44 controls, nine adolescent-limited antisocials, 21 APDs, and 13 late-onset antisocials from the community. Adult antisocial individuals, regardless of age of onset, were significantly taller and had greater body bulk than controls. Although groups tended to differ on weight, they did not differ on body mass index. In addition, APDs and adolescent-limited individuals reported greater psychosocial adversity than the other groups. Adversity did not account for height or bulk differences. Results suggest prior findings on height and bulk may apply to APD and support differentiating adolescent-limited and life-course persistent subgroups.

Invariance of the MAST across religious groups

OBJECTIVE

The Michigan Alcoholism Screening Test (MAST), a commonly used instrument of alcohol-related problems, was examined to determine whether it assessed the same constructs in individuals from religions with different proscriptions regarding the use of alcohol.

METHOD

The MAST was completed by participants in the longitudinal Joint Child Health Project when they were approximately 23 years old. Subjects of this study (N= 747; 505 men) were 465 Hindus, 223 Catholics and 59 Muslims who reported drinking alcohol. Measurement invariance, the determination that the same constructs are being measured across groups, was tested by comparing factor invariance using multigroup structural equation modeling.

RESULTS

The Hindu and Catholic groups had similar factor structures to those found in previous Australian, Canadian and U.S. samples. Metric invariance was obtained for the Hindu and Catholic groups, but not for the Muslim group.

CONCLUSIONS

These findings suggest the measurement of MAST factors is invariant across a fairly broad segment of the population in which the MAST might be used. However, the lack of invariance in this sample of Muslims suggests that the MAST is not an appropriate instrument to use among all groups of drinkers. These findings highlight the importance of testing for invariance when using psychological measures to compare heterogeneous samples.

Autonomic stress reactivity and executive functions in successful and unsuccessful criminal psychopaths from the community

A significant gap in the psychopathy literature is the lack of studies comparing "successful," nonconvicted psychopaths with "unsuccessful," convicted psychopaths. This study tested the hypothesis that successful psychopaths show increased autonomic stress reactivity and better neuropsychological function compared with unsuccessful psychopaths. A total of 26 controls, 16 unsuccessful psychopaths, and 13 successful psychopaths were assessed on psychophysiological measures recorded during an emotional manipulation, the Wisconsin Card Sorting Test (WCST), Wechsler Memory Scale--Revised subtests, and childhood stressors. Compared with controls, unsuccessful psychopaths showed reduced cardiovascular stress reactivity. In contrast, successful psychopaths showed heightened reactivity, better WCST performance, and more parental absence than unsuccessful psychopaths and controls. The implications of these findings and the generalizability of existing psychopathy research are discussed.

Autonomic stress reactivity and executive functions in successful and unsuccessful criminal psychopaths from the community

A significant gap in the psychopathy literature is the lack of studies comparing "successful," nonconvicted psychopaths with "unsuccessful," convicted psychopaths. This study tested the hypothesis that successful psychopaths show increased autonomic stress reactivity and better neuropsychological function compared with unsuccessful psychopaths. A total of 26 controls, 16 unsuccessful psychopaths, and 13 successful psychopaths were assessed on psychophysiological measures recorded during an emotional manipulation, the Wisconsin Card Sorting Test (WCST), Wechsler Memory Scale--Revised subtests, and childhood stressors. Compared with controls, unsuccessful psychopaths showed reduced cardiovascular stress reactivity. In contrast, successful psychopaths showed heightened reactivity, better WCST performance, and more parental absence than unsuccessful psychopaths and controls. The implications of these findings and the generalizability of existing psychopathy research are discussed.

Early educational and health enrichment at age 3-5 years is associated with increased autonomic and central nervous system arousal and orienting at age 11 years: evidence from the Mauritius Child Health Project

Little is known about the effects of environmental enrichment on psychophysiological measures of arousal and orienting in humans. This study tests the hypothesis that early educational and health enrichment is associated with long-term increases in psychophysiological orienting and arousal. One hundred children were experimentally assigned to a two-year enriched nursery school intervention at ages 3-5 years and matched at age 3 years on psychophysiological measures, gender, and ethnicity to 100 comparisons who received the normal educational experience. Children were retested 6-8 years later at age 11 years on skin conductance (SC) and electroencephalogram (EEG) measures of arousal and attention during pre- and postexperimental rest periods and during the continuous performance task. Nursery enrichment was associated with increased SC amplitudes, faster SC rise times, faster SC recovery times, and less slow-wave EEG during both rest and CPT conditions. This is believed to be the first study to show that early environmental enrichment is associated with long-term increases in psychophysiological orienting and arousal in humans. Results draw attention to the important influence of the early environment in shaping later psychophysiological functioning.

Three-factor model of schizotypal personality: invariance across culture, gender, religious affiliation, family adversity, and psychopathology

Whilst the syndrome approach to schizotypy has recently demonstrated differential correlates of a three-factor model of schizotypal personality, variations in the nature of these factors question a basic assumption of this approach. This study tested competing models of the factor structure of schizotypal personality using the Schizotypal Personality Questionnaire (SPQ) in a sample of 1,201 Mauritians. Factor invariance across gender, ethnicity, family adversity, and religion and across a psychopathologically select group was also assessed. Results suggest that a three-factor model, Cognitive-Perceptual Deficits, Interpersonal Deficits, and Disorganization, underlies individual differences across widely varying groups. Other competing three-factor schizotypal personality models did not fit the data better. It is argued that the three-factor Disorganized model is a well-replicated model of DSM schizotypal personality in community samples but possibly not in some clinical samples.

Elevated levels of cognitive-perceptual deficits in individuals with a family history of schizophrenia spectrum disorders

This study finds that the relatives of schizophrenics have elevated scores on the cognitive-perceptual factor of the schizotypal personality questionnaire (SPQ), particularly for the 'unusual perceptual experiences' and 'ideas of reference' subscales. These results support recent findings by Kremen et al. (1998) and suggest that previous failures to demonstrate elevated scores on 'positive' symptoms of schizotypy may be a function of instrumentation.

Structural characterization of a mutant peptide derived from ubiquitin: implications for protein folding

The formation of the N-terminal beta-hairpin of ubiquitin is thought to be an early event in the folding of this small protein. Previously, we have shown that a peptide corresponding to residues 1-17 of ubiquitin folds autonomously and is likely to have a native-like hairpin register. To investigate the causes of the stability of this fold, we have made mutations in the amino acids at the apex of the turn. We find that in a peptide where Thr9 is replaced by Asp, U(1-17)T9D, the native conformation is stabilized with respect to the wild-type sequence, so much so that we are able to characterize the structure of the mutant peptide fully by NMR spectroscopy. The data indicate that U(1-17)T9D peptide does indeed form a hairpin with a native-like register and a type I turn with a G1 beta-bulge, as in the full-length protein. The reason for the greater stability of the U(1-17)T9D mutant remains uncertain, but there are nuclear Overhauser effects between the side chains of Asp9 and Lys 11, which may indicate that a charge-charge interaction between these residues is responsible.

Treatment and prevention implications of antisocial personality disorder

Recent research efforts have focused on understanding the developmental nature of antisocial personality disorder (APD) in order to better develop intervention strategies. This article reviews what is known about biologic and environmental risk factors for the development of APD as well as issues surrounding treatment. Insights into how these factors may work together, and issues involving approaches to researching them, are discussed. Given the impact of this disorder on the lives of the affected individuals as well as society, prevention of this disorder may be a more important focus than intervention.

Reduced prefrontal gray matter volume and reduced autonomic activity in antisocial personality disorder

BACKGROUND

Major damage to gray and white matter in the prefrontal cortex and autonomic deficits have been found to result in pseudopsychopathic personality in patients with neurological disorders, but it is not known whether people with antisocial personality disorder (APD) in the community who do not have discernable brain trauma also have subtle prefrontal deficits.

METHODS

Prefrontal gray and white matter volumes were assessed using structural magnetic resonance imaging in 21 community volunteers with APD (APD group) and in 2 control groups, comprising 34 healthy subjects (control group), 26 subjects with substance dependence (substance-dependent group), and 21 psychiatric controls. Autonomic activity (skin conductance and heart rate) was also assessed during a social stressor in which participants gave a videotaped speech on their faults.

RESULTS

The APD group showed an 11.0% reduction in prefrontal gray matter volume in the absence of ostensible brain lesions and reduced autonomic activity during the stressor. These deficits predicted group membership independent of psychosocial risk factors.

CONCLUSIONS

To our knowledge, these findings provide the first evidence for a structural brain deficit in APD. This prefrontal structural deficit may underlie the low arousal, poor fear conditioning, lack of conscience, and decision-making deficits that have been found to characterize antisocial, psychopathic behavior.

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.