Multiple phylogenetically-diverse, differentially-virulent Burkholderia pseudomallei isolated from a single soil sample collected in Thailand

Burkholderia pseudomallei is a soil-dwelling bacterium endemic to Southeast Asia and northern Australia that causes the disease, melioidosis. Although the global genomic diversity of clinical B. pseudomallei isolates has been investigated, there is limited understanding of its genomic diversity across small geographic scales, especially in soil. In this study, we obtained 288 B. pseudomallei isolates from a single soil sample (~100g; intensive site 2, INT2) collected at a depth of 30cm from a site in Ubon Ratchathani Province, Thailand. We sequenced the genomes of 169 of these isolates that represent 7 distinct sequence types (STs), including a new ST (ST1820), based on multi-locus sequence typing (MLST) analysis. A core genome SNP phylogeny demonstrated that all identified STs share a recent common ancestor that diverged an estimated 796-1260 years ago. A pan-genomics analysis demonstrated recombination between clades and intra-MLST phylogenetic and gene differences. To identify potential differential virulence between STs, groups of BALB/c mice (5 mice/isolate) were challenged via subcutaneous injection (500 CFUs) with 30 INT2 isolates representing 5 different STs; over the 21-day experiment, eight isolates killed all mice, 2 isolates killed an intermediate number of mice (1-2), and 20 isolates killed no mice. Although the virulence results were largely stratified by ST, one virulent isolate and six attenuated isolates were from the same ST (ST1005), suggesting that variably conserved genomic regions may contribute to virulence. Genomes from the animal-challenged isolates were subjected to a bacterial genome-wide association study to identify genomic regions associated with differential virulence. One associated region is a unique variant of Hcp1, a component of the type VI secretion system, which may result in attenuation. The results of this study have implications for comprehensive sampling strategies, environmental exposure risk assessment, and understanding recombination and differential virulence in B. pseudomallei.

A pilot randomised controlled trial of befriending by volunteers in people with intellectual disability and depressive symptoms

BACKGROUND

People with intellectual disability (ID) are more likely to experience chronic depression compared with the general population, which may be compounded by loneliness and lower levels of social support. Befriending aims to provide social support and promote engagement in community activities. No randomised controlled trials have examined whether befriending improves symptoms of depression and social outcomes in people with ID. The aim of this pilot trial was to assess the feasibility and acceptability of a future larger trial of one-to-one befriending by volunteers in people with ID and depressive symptoms.

METHODS

Participants were adults with mild or moderate ID with a score of 5 or more on the Glasgow Depression Scale for People with Learning Disabilities (GDS-LD). They were randomised to the intervention arm (matched to a volunteer befriender for 6 months) or the control arm (usual care). Volunteers received training and supervision provided by two community befriending schemes. The main outcomes were feasibility of recruitment (minimum target n = 35), retention rate of participants, adherence (minimum 10 meetings), acceptability of the intervention, changes in depressive symptoms (assessed at baseline and 6 months) and feasibility of collecting data for a health economic analysis.

RESULTS

Recruitment was challenging, and only 16 participants with ID and 10 volunteers were recruited. Six participants were matched with a volunteer and no participants dropped out (except for two volunteers). Four participants completed 10 meetings (mean 11.8). Befriending was thought to be acceptable, but modifications were suggested. An exploratory analysis suggested that GDS-LD score was lower in the intervention group compared with the control group after adjusting for baseline scores, but not significant (adjusted mean difference: -4.0; 95% confidence interval: -11.2 to 3.2).

CONCLUSIONS

A large trial would not be feasible based on the recruitment strategies employed in this study. A further feasibility study addressing these challenges or the use of other study designs should be considered.

426 PREVALENCE OF, AND RISK FACTORS FOR, DEMENTIA IN ADULT OUTPATIENT REFERRALS TO A REGIONAL REFERRAL HOSPITAL IN ARUSHA, TANZANIA

Introduction

The global burden of dementia is increasing, with the greatest increase predicted to occur in sub-Saharan Africa (SSA). Despite this there are limited previous data on the prevalence of, and risk factors for, dementia in SSA. This study aimed to estimate the prevalence of dementia, and investigate its associations, in those aged 60 years and older attending the outpatient department of Mount Meru Hospital in northern Tanzania. This is the first hospital-based outpatient dementia prevalence and risk factors study to be conducted in an east African population.

Methods

This was a one-phase cross-sectional study. Adults aged 60 years and over attending medical outpatients were screened for dementia using The Identification and Intervention for Dementia in Elderly Africans cognitive screening tool. Those who scored ≤9 were clinically assessed using the DSM-IV criteria. Demographic, medical comorbidity and lifestyle information were collected during a clinical assessment.

Results

Prevalence of dementia was 5.0% (95% confidence interval: 3.7–6.3). Binary logistic regression found female sex (odds ratio (OR) = 2.778), having no formal education (OR = 6.088), quantity of alcohol consumption (units/week) (OR = 1.080), uncorrected visual impairment (OR = 4.260), body mass index <18.5 kg/m2 (OR = 6.588) and stroke (OR = 15.790 with wide 95% confidence interval (3.48–74.475)) to be significantly, independently associated with dementia.

Conclusions

The prevalence of dementia in this population is lower than previously reported community-based rates in Tanzania, and similar to those in high-income countries. This is the first time the association between uncorrected visual impairment and dementia has been reported in SSA. Other associations identified are in keeping with previous literature. Further research on the management of dementia and its risk factors, and the support and education of carers and patients in east African populations is required.

Bacterial Genome Wide Association Studies (bGWAS) and Transcriptomics Identifies Cryptic Antimicrobial Resistance Mechanisms in Acinetobacter baumannii

Antimicrobial resistance (AMR) in the nosocomial pathogen, Acinetobacter baumannii, is becoming a serious public health threat. While some mechanisms of AMR have been reported, understanding novel mechanisms of resistance is critical for identifying emerging resistance. One of the first steps in identifying novel AMR mechanisms is performing genotype/phenotype association studies; however, performing these studies is complicated by the plastic nature of the A. baumannii pan-genome. In this study, we compared the antibiograms of 12 antimicrobials associated with multiple drug families for 84 A. baumannii isolates, many isolated in Arizona, USA. in silico screening of these genomes for known AMR mechanisms failed to identify clear correlations for most drugs. We then performed a bacterial genome wide association study (bGWAS) looking for associations between all possible 21-mers; this approach generally failed to identify mechanisms that explained the resistance phenotype. In order to decrease the genomic noise associated with population stratification, we compared four phylogenetically-related pairs of isolates with differing susceptibility profiles. RNA-Sequencing (RNA-Seq) was performed on paired isolates and differentially-expressed genes were identified. In these isolate pairs, five different potential mechanisms were identified, highlighting the difficulty of broad AMR surveillance in this species. To verify and validate differential expression, amplicon sequencing was performed. These results suggest that a diagnostic platform based on gene expression rather than genomics alone may be beneficial in certain surveillance efforts. The implementation of such advanced diagnostics coupled with increased AMR surveillance will potentially improve A. baumannii infection treatment and patient outcomes.

Coccidioidal Meningitis in New York Traced to Texas by Fungal Genomic Analysis

A child developed hydrocephalus. Sixteen months later, it was discovered to be a complication of coccidioidal meningitis. The infection's source was uncertain until genomic analysis of the fungal isolate identified its origin to be a visit to Beeville, Texas. Improved national reporting of cases of coccidioidomycosis might reduce diagnostic delays.

Genomic analyses of Staphylococcus aureus clonal complex 45 isolates does not distinguish nasal carriage from bacteraemia

Staphylococcus aureus is a colonizing opportunistic pathogen and a leading cause of bloodstream infection with high morbidity and mortality. S. aureus carriage frequency is reportedly between 20 and 40 % among healthy adults, with S. aureus colonization considered to be a risk factor for S. aureus bacteraemia. It is unknown whether a genetic component of the bacterium is associated with S. aureus bacteraemia in comparison to nasal carriage strains. Previous association studies primarily focusing on the clinical outcome of an S. aureus infection have produced conflicting results, often limited by study design challenged by sample collections and the clonal diversity of S. aureus. To date, no study has investigated whether genomic features separate nasal carriage isolates from S. aureus bacteraemia isolates within a single clonal lineage. Here we have investigated whether genomic features, including single-nucleotide polymorphisms (SNPs), genes, or kmers, distinguish S. aureus nasal carriage isolates from bacteraemia isolates that all belong to the same clonal lineage [clonal complex 45 (CC45)] using whole-genome sequencing (WGS) and a genome-wide association (GWA) approach. From CC45, 100 isolates (50 bacteraemia and 50 nasal carriage, geographically and temporally matched) from Denmark were whole-genome sequenced and subjected to GWA analyses involving gene copy number variation, SNPs, gene content, kmers and gene combinations, while correcting for lineage effects. No statistically significant association involving SNPs, specific genes, gene variants, gene copy number variation, or a combination of genes was identified that could distinguish bacteraemia isolates from nasal carriage isolates. The presented results suggest that all S. aureus nasal CC45 isolates carry the potential to cause invasive disease, as no core or accessory genome content or variations were statistically associated with invasiveness.

Genomic characterization of Parengyodontium americanum sp. nov

Modern genome analysis and phylogenomic methods have increased the number of fungal species, as well as enhanced appreciation of the degree of diversity within the fungal kingdom. In this context, we describe a new Parengyodontium species, P. americanum, which is phylogenetically related to the opportunistic human fungal pathogen P. album. Five unusual fungal isolates were recovered from five unique and confirmed coccidioidomycosis patients, and these isolates were subsequently submitted to detailed molecular and morphological identification procedures to determine identity. Molecular and morphological diagnostic analyses showed that the isolates belong to the Cordycipitaceae. Subsequently, three representative genomes were sequenced and annotated, and a new species, P. americanum, was identified. Using various genomic analyses, gene family expansions related to novel compounds and potential for ability to grow in diverse habitats are predicted. A general description of the genomic composition of this newly described species and comparison of genome content with Beauveria bassiana, Isaria fumosorosea and Cordyceps militaris shows a shared core genome of 6371 genes, and 148 genes that appear to be specific for P. americanum. This work provides the framework for future investigations of this interesting fungal species.

Geographic variation in the use of lymphadenectomy and external-beam radiotherapy for endometrial cancer: a cross-sectional analysis of population-based data

OBJECTIVE

To quantify geographic variation in the use of lymphadenectomy and/or external-beam radiotherapy (EBRT) for endometrial cancer in England.

DESIGN

Cross-sectional analysis of population-based data.

SETTING

English cancer registry data, linked to chemotherapy, radiotherapy and hospital episodes statistics data.

POPULATION

Twenty-two thousand four hundred and eighty-three women with endometrial cancer presenting without clinical or radiological evidence of distant metastatic spread, diagnosed in England from 2013 to 2016.

METHODS

Proportions of patients receiving lymphadenectomy and/or EBRT were compared across 19 Cancer Alliances, to identify variations in clinical practice. Two separate logistic regression models assessed the impact on variation of adjustment for tumour and patient characteristics.

MAIN OUTCOME MEASURES

Receipt of lymphadenectomy, receipt of EBRT.

RESULTS

There was substantial variation by Cancer Alliance in the adjusted proportion of women with endometrial cancer receiving lymphadenectomy (range 5% [95% CI 4-6%] to 48% [95% CI 45-52%]) and EBRT (range 10% [95% CI 7-12%] to 31% [95% CI 28-33%]), after adjusting for variation in pathological grade, age, comorbidities, deprivation, ethnic group and (EBRT only) FIGO stage. Different approaches to clinical practice were identified; (i) one Cancer Alliance had significantly higher than average lymphadenectomy and significantly lower than average EBRT use, (ii) three had high use of both lymphadenectomy and EBRT, (iii) one had low lymphadenectomy use and high EBRT use, and (iv) three had low use of both lymphadenectomy and EBRT.

CONCLUSIONS

Lymphadenectomy is probably used to triage for EBRT when lymphadenectomy use is high and EBRT use is low. This is probably a result of variation in local endometrial cancer management guidelines, suggesting that UK recommendations should be clarified.

TWEETABLE ABSTRACT

There is geographic variation in England in the use of lymphadenectomy and radiotherapy to treat endometrial cancer.

Zoonotic Source Attribution of Salmonella enterica Serotype Typhimurium Using Genomic Surveillance Data, United States

Increasingly, routine surveillance and monitoring of foodborne pathogens using whole-genome sequencing is creating opportunities to study foodborne illness epidemiology beyond routine outbreak investigations and case–control studies. Using a global phylogeny of Salmonella enterica serotype Typhimurium, we found that major livestock sources of the pathogen in the United States can be predicted through whole-genome sequencing data. Relatively steady rates of sequence divergence in livestock lineages enabled the inference of their recent origins. Elevated accumulation of lineage-specific pseudogenes after divergence from generalist populations and possible metabolic acclimation in a representative swine isolate indicates possible emergence of host adaptation. We developed and retrospectively applied a machine learning Random Forest classifier for genomic source prediction of Salmonella Typhimurium that correctly attributed 7 of 8 major zoonotic outbreaks in the United States during 1998–2013. We further identified 50 key genetic features that were sufficient for robust livestock source prediction.

NASP: an accurate, rapid method for the identification of SNPs in WGS datasets that supports flexible input and output formats

Whole-genome sequencing (WGS) of bacterial isolates has become standard practice in many laboratories. Applications for WGS analysis include phylogeography and molecular epidemiology, using single nucleotide polymorphisms (SNPs) as the unit of evolution. NASP was developed as a reproducible method that scales well with the hundreds to thousands of WGS data typically used in comparative genomics applications. In this study, we demonstrate how NASP compares with other tools in the analysis of two real bacterial genomics datasets and one simulated dataset. Our results demonstrate that NASP produces similar, and often better, results in comparison with other pipelines, but is much more flexible in terms of data input types, job management systems, diversity of supported tools and output formats. We also demonstrate differences in results based on the choice of the reference genome and choice of inferring phylogenies from concatenated SNPs or alignments including monomorphic positions. NASP represents a source-available, version-controlled, unit-tested method and can be obtained from tgennorth.github.io/NASP.

Measurement Properties of the Nordic Questionnaire for Psychological and Social Factors at Work: A Rasch Analysis

The main aim of this study was to evaluate the measurement properties of the Nordic Questionnaire for Psychological and Social Factors at Work (QPS Nordic) and the domains of demand, control and support. The Rasch analysis (RUMM 2030) was based on responses from 226 subjects with back pain who completed the QPS Nordic dimensions of demand, control, and social support (30 items) at one year follow up. The Rasch analysis revealed disordered thresholds in a total of 25 of the 30 items. The domains of demand, control and support fit the Rasch model when analyzed separately. The demand domain was well targeted, whereas patients with current neck and back pain had lower control and higher support than reflected by the questions. Two items revealed DIF by gender, otherwise invariance to age, gender, occupation and sick-leave was documented. The demand, control support domains of QPS Nordic comprised unidimensional constructs with adequate measurement properties.

Genomic Analysis of the Emergence and Rapid Global Dissemination of the Clonal Group 258 Klebsiella pneumoniae Pandemic

Multidrug-resistant Klebsiella pneumoniae producing the KPC carbapenemase have rapidly spread throughout the world, causing severe healthcare-associated infections with limited antimicrobial treatment options. Dissemination of KPC-producing K. pneumoniae is largely attributed to expansion of a single dominant strain, ST258. In this study, we explore phylogenetic relationships and evolution within ST258 and its clonal group, CG258, using whole genome sequence analysis of 167 isolates from 20 countries collected over 17 years. Our results show a common ST258 ancestor emerged from its diverse parental clonal group around 1995 and likely acquired blaKPC prior to dissemination. Over the past two decades, ST258 has remained highly clonal despite diversity in accessory elements and divergence in the capsule polysaccharide synthesis locus. Apart from the large recombination event that gave rise to ST258, few mutations set it apart from its clonal group. However, one mutation occurs in a global transcription regulator. Characterization of outer membrane protein sequences revealed a profile in ST258 that includes a truncated OmpK35 and modified OmpK37. Our work illuminates potential genomic contributors to the pathogenic success of ST258, helps us better understand the global dissemination of this strain, and identifies genetic markers unique to ST258.

Using Whole Genome Analysis to Examine Recombination across Diverse Sequence Types of Staphylococcus aureus

Staphylococcus aureus is an important clinical pathogen worldwide and understanding this organism's phylogeny and, in particular, the role of recombination, is important both to understand the overall spread of virulent lineages and to characterize outbreaks. To further elucidate the phylogeny of S. aureus, 35 diverse strains were sequenced using whole genome sequencing. In addition, 29 publicly available whole genome sequences were included to create a single nucleotide polymorphism (SNP)-based phylogenetic tree encompassing 11 distinct lineages. All strains of a particular sequence type fell into the same clade with clear groupings of the major clonal complexes of CC8, CC5, CC30, CC45 and CC1. Using a novel analysis method, we plotted the homoplasy density and SNP density across the whole genome and found evidence of recombination throughout the entire chromosome, but when we examined individual clonal lineages we found very little recombination. However, when we analyzed three branches of multiple lineages, we saw intermediate and differing levels of recombination between them. These data demonstrate that in S. aureus, recombination occurs across major lineages that subsequently expand in a clonal manner. Estimated mutation rates for the CC8 and CC5 lineages were different from each other. While the CC8 lineage rate was similar to previous studies, the CC5 lineage was 100-fold greater. Fifty known virulence genes were screened in all genomes in silico to determine their distribution across major clades. Thirty-three genes were present variably across clades, most of which were not constrained by ancestry, indicating horizontal gene transfer or gene loss.

Valley fever: finding new places for an old disease: Coccidioides immitis found in Washington State soil associated with recent human infection

We used real-time polymerase chain reaction and culture to demonstrate persistent colonization of soils by Coccidioides immitis, an agent of valley fever, in Washington State linked to recent human infections and located outside the endemic range. Whole-genome sequencing confirmed genetic identity between isolates from soil and one of the case-patients.

Predicting health-related quality of life 2 years after moderate-to-severe traumatic brain injury

AIMS

To describe health-related quality of life (HRQL) 2 years after moderate-to-severe traumatic brain injury (TBI) and to assess predictors of HRQL.

MATERIALS AND METHODS

A prospective cohort study of 91 patients, aged 16-55 years, admitted with moderate-to-severe TBI to a trauma referral centre between 2005 and 2007, with follow-up at 1 and 2 years. Mean age was 31.1 (SD = 11.3) years, and 77% were men. Injury severity was evaluated by the Glasgow Coma Scale (GCS), head CT scan (using a modified Marshall Classification), Injury Severity Score (ISS) and post-traumatic amnesia (PTA). The Functional Independence Measure (FIM), Community Integration Questionnaire (CIQ), Beck Depression Inventory (BDI) and Medical Outcomes 36-item Short Form Health Survey (SF-36) were administered at follow-up visits. The main outcome measures were the Physical Component Summary (PCS) and Mental Component Summary (MCS) of the SF-36.

RESULTS

HRQL appears to be relatively stable between 1 and 2 years after injury. In the multivariate linear regression, younger age (β = -0.20, P = 0.032), more severe TBI (β = 0.28, P = 0.016), more severe overall trauma (β = 0.22, P = 0.026), higher levels of community integration (β = 0.36, P = 0.019) and higher positive change in PCS scores from 1 to 2 years (β = 0.41, P < 0.001) predicted better self-reported physical health 2 years post-TBI. Lower scores for depression (β = -0.70, P < 0.001) and a higher positive change in MCS scores (β = 0.62, P < 0.001) predicted better self-reported mental health.

CONCLUSIONS

Future interventions should focus on aspects related to HRQL that are more easily modified, such as physical functioning, home and social integration, productivity, and mental and emotional status.

A German genome-wide linkage scan for type 2 diabetes supports the existence of a metabolic syndrome locus on chromosome 1p36.13 and a type 2 diabetes locus on chromosome 16p12.2

AIMS/HYPOTHESIS

The aim was to identify type 2 diabetes susceptibility regions in 250 German families.

SUBJECTS AND METHODS

We conducted a genome-wide linkage scan using 439 short tandem repeat polymorphisms at an average resolution of 7.76 +/- 3.80 cM (Marshfield). In an affected-only-design (affected sib pairs), we performed nonparametric multipoint linkage analyses. Conditional analyses were applied where linkage signals were found in the baseline analyses.

RESULTS

We identified two loci with nominal evidence for linkage on chromosomes 1p36.13 and 16p12.2 (D1S3669, 37.05 cM, logarithmic odds ratio [LOD] = 1.49, p = 0.004; D16S403, 43.89 cM, LOD = 1.85, p = 0.002). D16S403 crossed the empirically obtained threshold of genome-wide suggestive significance of LOD = 1.51. Positive findings in those regions have been reported by the following other linkage studies on: (1) symptomatic/clinical gall bladder disease with type 2 diabetes in Mexican Americans from the San Antonio Family Diabetes/Gallbladder Study (LOD = 3.7, D1S1597-D1S407, 29.93-33.75 cM); (2) body size-adiposity in another Mexican American population (D1S1597, LOD = 2.53, 29.93 cM); (3) lipid abnormalities (LOD = 3.1, D1S2826-D1S513, 41.92-60.01 cM); and (4) hypertension in Australian sib pairs (LOD = 3.1, D1S2834-D1S2728, 31.02-33.75 cM); as well as (5) a meta-analysis of four European type 2 diabetes-related genome scans (LOD = 1.09, D16S412, 42.81 cM). In linkage analyses conditional on evidence for linkage at D16S403 we identified a LOD increase (Delta LOD) of 1.55 (p = 0.0075) at D17S2180. Similar conditioning on D17S2180 revealed evidence for interaction with D1S3669 (Delta LOD = 1.67, p = 0.0055), D16S403 (Delta LOD = 1.48, p = 0.0091) and another locus on chromosome 1 where several genome scans have reported evidence for linkage ( approximately 200 cM, Delta LOD = 1.60, p = 0.0066).

CONCLUSIONS/INTERPRETATION

Our results and the findings of other studies are consistent with the presence of a locus for a complex metabolic syndrome on chromosome 1p36.13.

Long-chain 3-hydroxyacylCoA dehydrogenase deficiency: a new case presenting with liver dysfunction, cholestasis and fibrosis

A cholestatic 6-mo-old girl was admitted to our department because she recently presented with hypotonia and lethargy, apparently due to moderate and transient hypoglycaemia. Her urine contained 3-hydroxy-dicarboxylic acids of 12 to 14 carbons in length and her plasma acylcarnitine profile was consistent with long-chain 3-hydroxyacylCoA dehydrogenase deficiency. This diagnosis was confirmed by enzyme studies. This deficiency was due to a G1528C mutation on the paternal allele (mutation on the maternal allele as yet not identified). The patient improved dramatically with medium-chain triglyceride supplementation.

CONCLUSION

Early cholestasis and hepatic fibrosis must lead to search for long-chain 3-hydroxyacylCoA dehydrogenase deficiency, particularly when hypoketotic hypoglycaemia is present.

Role of common gene variations in the molecular pathogenesis of short-chain acyl-CoA dehydrogenase deficiency

ABSTRACT Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is considered a rare inherited mitochondrial fatty acid oxidation disorder. Less than 10 patients have been reported, diagnosed on the basis of ethylmalonic aciduria and low SCAD activity in cultured fibroblast. However, mild ethylmalonic aciduria, a biochemical marker of functional SCAD deficiency in vivo, is a common finding in patients suspected of having metabolic disorders. Based on previous observations, we have proposed that ethylmalonic aciduria in a small proportion of cases is caused by pathogenic SCAD gene mutations, and SCAD deficiency can be demonstrated in fibroblasts. Another - much more frequent - group of patients with mild ethylmalonic aciduria has functional SCAD deficiency due to the presence of susceptibility SCAD gene variations, i.e. 625G>A and 511C>T, in whom a variable or moderately reduced SCAD activity in fibroblasts may still be clinically relevant. To substantiate this notion we performed sequence analysis of the SCAD gene in 10 patients with ethylmalonic aciduria and diagnosed with SCAD deficiency in fibroblasts. Surprisingly, only one of the 10 patients carried pathogenic mutations in both alleles, while five were double heterozygotes for a pathogenic mutation in one allele and the 625G>A susceptibility variation in the other. The remaining four patients carried only either the 511C>T or the 625G>A variations in each allele. Our findings document that patients carrying these SCAD gene variations may develop clinically relevant SCAD deficiency, and that patients with even mild ethylmalonic aciduria should be tested for these variations.

Computer-aided diagnosis of pulmonary nodules: results of a large-scale observer test

PURPOSE

To determine the effect of computer-aided diagnosis (CAD) on the accuracy of pulmonary nodule detection.

MATERIALS AND METHODS

Twenty abnormal chest radiographs, each with a single nodule, and 20 normal radiographs were digitized with a laser scanner. These images were analyzed by using a computer program that indicates areas that may represent pulmonary nodules. The radiographs were displayed on computer workstations in randomized order, and an observer test was performed. One hundred forty-six observers participated, including 23 chest radiologists, 54 other radiologists, 27 radiology residents, and 42 nonradiologists. Cases were interpreted first without and then with the use of CAD. The observers' responses were recorded on a continuous confidence rating scale. Detection accuracy both with and without CAD was evaluated with receiver operating characteristic analysis.

RESULTS

The detection accuracy was significantly higher for all categories of observers when CAD was used (chest radiologists, P = 8 x 10(-6); other radiologists, P = 2 x 10(-16); radiology residents, P = 6 x 10(-7); and nonradiologists, P = 8 x 10(-9)).

CONCLUSION

CAD has the potential to improve diagnostic accuracy in the detection of lung nodules on digital radiographs.

Identification of four novel mutations in patients with carnitine palmitoyltransferase II (CPT II) deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency, an autosomal recessive disorder of fatty-acid oxidation, presents as three distinct phenotypes (neonatal, infantile, and adult onset). In order to investigate the molecular basis of these three phenotypes, six patients with CPT II deficiency have been studied. All six unrelated patients in this study experienced the clinical symptoms of CPT II deficiency. Three patients had the neonatal form, one had the milder infantile form, and the remaining two had the adult-onset form with "muscular" symptoms only. Their diagnoses were based upon in vitro analysis of the mitochondrial beta-oxidation pathway in fibroblasts and standard enzyme assays. We devised a method to screen the entire coding sequence and flanking splice junction of the CPT II gene. A total of six different mutations have been identified, including four novel mutations. Among them, the previously reported common mutation, S113L, was only found in 3 of 12 variant alleles. Three of the six mutations have been identified in a few unrelated patients, while the remaining three have been found in single families. This study, as well as those by others, indicates genetic heterogeneity in this disease. In addition to tabulating the mutations, the correlation of mutant genotype to clinical phenotype is briefly discussed.

Infantile fibre type disproportion, myofibrillar lysis and cardiomyopathy: a disorder in three unrelated Dutch families

An apparently new cardioskeletal myopathy is reported in three unrelated families. Five infants were affected by rapidly progressive generalized muscle weakness, with onset shortly after birth, and dilated cardiomyopathy. All had generalized tremor (clonus) starting in the first week of life. The disease was lethal in all cases between 4 and 6 months. Muscle biopsy, performed in four of the five patients, showed a light microscopic pattern of small type I and normal-sized type II fibres. By electron microscopy small fibres were affected by myofibrillar disruption and swelling of organelles. Findings in blood and urine suggested a disturbance in energy metabolism but an extensive search for respiratory chain disorders and disorders of mitochondrial fatty acid oxidation in frozen muscle and cultured fibroblasts was negative. The findings support a new progressive autosomal recessive infantile cardioskeletal myopathy in which type I muscle fibres are preferentially affected.

Mitochondrial very-long-chain acyl-coenzyme A dehydrogenase deficiency: clinical characteristics and diagnostic considerations in 30 patients

Very-long-chain acyl-CoA dehydrogenase (VLCAD) is an enzyme catalyzing the dehydrogenation of long-chain fatty acids in the first step of mitochondrial fatty acid oxidation. Using an ETF (electron transfer flavoprotein, the physiological electron acceptor of VLCAD) reduction assay, we identified VLCAD deficiency in cultured skin fibroblasts or liver tissue from 30 patients in 27 families. They clinically presented two phenotypes: a 'severe' presentation characterized by an early onset of symptoms, with hypertrophic cardiomyopathy and a high incidence of death, and a 'mild' form with hypoketotic hypoglycaemia, resembling MCAD (medium-chain acyl-CoA dehydrogenase) deficiency. Cells isolated from patients who develop cardiomyopathy characteristically accumulate longer-chain length acylcarnitines (hexadecanoylcarnitine and tetradecanoylcarnitine) when incubated with palmitate. However, cells from patients with the hypoglycaemic presentation produced relatively shorter-chain-length intermediates (mainly dodecanoylcarnitine). Inhibition of carnitine palmitoyl transferase I, in vitro, eliminated these intermediates with cells from both phenotypes indicating their intramitochondrial origin. Although the explanation for these distinct biochemical findings is not obvious, the correlation with the two phenotypes provides an opportunity for accurate prognosis and early implementation of appropriate treatment. Prenatal diagnosis of this life-threatening disorder was successfully performed in seven pregnancies in six of those families by assay of trophoblasts or amniocytes. In an at risk family, diagnosis of an affected fetus by measurement of VLCAD activity in noncultured chorionic villi allowed termination of the pregnancy before 13 weeks of gestation.

The suggestibility of children's memory for being touched: planting, erasing, and changing memories

Investigates recent claims that it is relatively easy to suggestively plant false memories in children, by comparing the relative vulnerability to suggestibility of changed, planted, and erased memories. 80 4-year-olds and 80 10-year-olds either were touched in a specific way or were not touched at all, and it was later suggested that a different touch, a completely new touch, or no touch at all had occurred. The suggestibility effect occurred only in the changed memory condition; the difference between the experimental changed condition and the corresponding control condition was significant. In the planted and erased memory conditions no suggestibility effect occurred; there was no significant reduction in the experimental groups relative to the corresponding control conditions. Thus, although it is relatively easy to suggest to a child a change in an event that was experienced, it is less likely that an event can be planted in or erased from memory. It is thus inappropriate to provide courtroom testimony regarding the probability of suggestively planting false memories based on the classic suggestibility research, which has largely been restricted to the study of suggestively changing memories.

Methylmalonic aciduria in pregnancy: a case report

Methylmalonic aciduria is a rare metabolic disorder of amino acid metabolism that is characterized by accumulation of large amounts of methylmalonic acid in the blood and urine. To our knowledge this is the first case report of a patient with methylmalonic aciduria who carried a pregnancy to term; the outcome was favorable despite high levels of methylmalonic acid in the serum and urine.

Single-dose antibiotic prophylaxis for patients undergoing extended pelvic surgery for gynecologic malignancy

The comparative efficacy of single-dose antibiotic prophylaxis was retrospectively evaluated in 116 patients undergoing extended pelvic surgical procedures with curative intent. During the 24-month period, other important variables such as surgeon's experience, duration of preoperative hospitalization, preoperative preparation, method of hair removal, suture type, suture size, use of drains, use of cautery, and abdominal closure were controlled. The overall surgical site infection rate was 4.3% after radical hysterectomy with lymphadenectomy and 4.5% after total hysterectomy with lymphadenectomy. In this clinical situation the use of a single dose of antibiotic prophylaxis theoretically decreases cost and patient exposure and appears to be as efficacious as a multiple-dose regimen.

DX alpha gene polymorphism in Graves' disease

An HLA-DX alpha gene polymorphism was analysed by Southern blotting in 49 British patients with Graves' disease and 61 control subjects. Two previously described allelic fragments of Taq I digested genomic DNA at 2.1 kb (U) and 1.9 kb (L) were found. The genotype frequencies for UU, UL and LL did not differ from the controls in Graves' disease, either for the whole groups or when subdivided into HLA-DR3-positive and -negative subjects. There was a significant association of the U allele with HLA-DR3 in both controls (P less than 0.05) and Graves' disease (P less than 0.025). The results indicate that DX alpha polymorphism is not primarily associated with Graves' disease. The findings differ from recent studies which showed that DX alpha polymorphisms may contribute to susceptibility in other DR3-associated autoimmune diseases.

T-cell receptor alpha chain V region polymorphism linked to primary autoimmune hypothyroidism but not Graves' disease

T-cell receptor alpha- and beta-chain polymorphisms have been investigated in patients with autoimmune thyroid disease. Using a cDNA probe for the T-cell receptor alpha chain, a 1.4-kb V alpha Taq I restriction fragment was found in 25 of 33 patients with autoimmune hypothyroidism compared to 33 of 61 control subjects (p less than 0.05) and 16 of 43 patients with Graves' disease (p less than 0.001 compared to patients with autoimmune hypothyroidism). Moreover, when Graves' patients were divided according to HLA-DR3 status, there was a significantly reduced frequency of the 1.4-kb V alpha fragment in HLA-DR3-negative patients (p less than 0.05 compared to controls). There was no significant association of either thyroid disorder with polymorphisms of the T-cell receptor alpha- or beta-chain-constant region genes, after Taq I and Bgl II digestion, respectively. These results show that inherited variation in T-cell receptor genes, recognizable before any somatic event has taken place, may play a role in susceptibility to autoimmune disease.

Biotinidase deficiency: accumulation of lactate in the brain and response to physiologic doses of biotin

Biotinidase deficiency is the most common cause of late onset, biotin-responsive multiple carboxylase deficiency (MCD). We studied the two oldest known boys with this disorder who had high CSF content of lactate that could have contributed to the clinical disorder. The symptoms of these patients implied that near physiologic, rather than pharmacologic, doses of biotin may be sufficient for treatment.

Increased activity of creatine kinase isoenzyme MB in a theophylline-intoxicated patient

A 78-year-old woman had increased activities of creatine kinase (CK; EC 2.7.3.2) and CK-MB isoenzyme in her serum, associated with severe theophylline intoxication. The time course for CK-MB activity was similar to that from an acute myocardial infarction. Clinical findings, however, including electrocardiograms, did not support the diagnosis of myocardial infarction. We suggest caution in interpreting CK-MB results in severe theophylline intoxication.

Increased activity of creatine kinase isoenzyme MB in a theophylline-intoxicated patient

A 78-year-old woman had increased activities of creatine kinase (CK; EC 2.7.3.2) and CK-MB isoenzyme in her serum, associated with severe theophylline intoxication. The time course for CK-MB activity was similar to that from an acute myocardial infarction. Clinical findings, however, including electrocardiograms, did not support the diagnosis of myocardial infarction. We suggest caution in interpreting CK-MB results in severe theophylline intoxication.

Anti-inflammatory action of dexamethasone in vitrectomy infusion fluid

Vitrectomy and lensectomy were performed in rabbits with infusion fluid containing dexamethasone. No ocular toxicity was observed in eyes that received dexamethasone up to a concentration of 400 micrograms/ml. Utilizing sensitive radioimmunoassay techniques after surgery, we observed significant reduction in ocular albumin levels in eyes treated with dexamethasone when compared with control eyes in which dexamethasone was not used. However, there was no significant difference in immunoglobulin levels between eyes from both groups.

Rhabdomyolysis in a patient with nonoliguric renal failure: similarities to the toxic-shock syndrome

We have described a 13-year-old girl with idiopathic rhabdomyolysis, myoglobinuria, and nonoliguric renal failure. The biochemical abnormalities and enzyme and isoenzyme values and their interrelationship to the hosptial course are stressed. We believe our patient's condition had marked similarities to the toxic-shock syndrome. The case illustrates the importance of the rapid recognition of myoglobinuria so that its potentially fatal biochemical abnormalities may be expeditiously identified and treated.