Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Polygenic risk for severe psychopathology among Europeans is associated with major depressive disorder in Han Chinese women

BACKGROUND

Previous studies have demonstrated that several major psychiatric disorders are influenced by shared genetic factors. This shared liability may influence clinical features of a given disorder (e.g. severity, age at onset). However, findings have largely been limited to European samples; little is known about the consistency of shared genetic liability across ethnicities.

METHOD

The relationship between polygenic risk for several major psychiatric diagnoses and major depressive disorder (MDD) was examined in a sample of unrelated Han Chinese women. Polygenic risk scores (PRSs) were generated using European discovery samples and tested in the China, Oxford, and VCU Experimental Research on Genetic Epidemiology [CONVERGE (maximum N = 10 502)], a sample ascertained for recurrent MDD. Genetic correlations between discovery phenotypes and MDD were also assessed. In addition, within-case characteristics were examined.

RESULTS

European-based polygenic risk for several major psychiatric disorder phenotypes was significantly associated with the MDD case status in CONVERGE. Risk for clinically significant indicators (neuroticism and subjective well-being) was also associated with case-control status. The variance accounted for by PRS for both psychopathology and for well-being was similar to estimates reported for within-ethnicity comparisons in European samples. However, European-based PRS were largely unassociated with CONVERGE family history, clinical characteristics, or comorbidity.

CONCLUSIONS

The shared genetic liability across severe forms of psychopathology is largely consistent across European and Han Chinese ethnicities, with little attenuation of genetic signal relative to within-ethnicity analyses. The overall absence of associations between PRS for other disorders and within-MDD variation suggests that clinical characteristics of MDD may arise due to contributions from ethnicity-specific factors and/or pathoplasticity.

SNP-based heritability estimates of the personality dimensions and polygenic prediction of both neuroticism and major depression: findings from CONVERGE

Biometrical genetic studies suggest that the personality dimensions, including neuroticism, are moderately heritable (~0.4 to 0.6). Quantitative analyses that aggregate the effects of many common variants have recently further informed genetic research on European samples. However, there has been limited research to date on non-European populations. This study examined the personality dimensions in a large sample of Han Chinese descent (N=10 064) from the China, Oxford, and VCU Experimental Research on Genetic Epidemiology study, aimed at identifying genetic risk factors for recurrent major depression among a rigorously ascertained cohort. Heritability of neuroticism as measured by the Eysenck Personality Questionnaire (EPQ) was estimated to be low but statistically significant at 10% (s.e.=0.03, P=0.0001). In addition to EPQ, neuroticism based on a three-factor model, data for the Big Five (BF) personality dimensions (neuroticism, openness, conscientiousness, extraversion and agreeableness) measured by the Big Five Inventory were available for controls (n=5596). Heritability estimates of the BF were not statistically significant despite high power (>0.85) to detect heritabilities of 0.10. Polygenic risk scores constructed by best linear unbiased prediction weights applied to split-half samples failed to significantly predict any of the personality traits, but polygenic risk for neuroticism, calculated with LDpred and based on predictive variants previously identified from European populations (N=171 911), significantly predicted major depressive disorder case-control status (P=0.0004) after false discovery rate correction. The scores also significantly predicted EPQ neuroticism (P=6.3 × 10-6). Factor analytic results of the measures indicated that any differences in heritabilities across samples may be due to genetic variation or variation in haplotype structure between samples, rather than measurement non-invariance. Findings demonstrate that neuroticism can be significantly predicted across ancestry, and highlight the importance of studying polygenic contributions to personality in non-European populations.

Individual aggregates of amyloid beta induce temporary calcium influx through the cell membrane of neuronal cells

Local delivery of amyloid beta oligomers from the tip of a nanopipette, controlled over the cell surface, has been used to deliver physiological picomolar oligomer concentrations to primary astrocytes or neurons. Calcium influx was observed when as few as 2000 oligomers were delivered to the cell surface. When the dosing of oligomers was stopped the intracellular calcium returned to basal levels or below. Calcium influx was prevented by the presence in the pipette of the extracellular chaperone clusterin, which is known to selectively bind oligomers, and by the presence a specific nanobody to amyloid beta. These data are consistent with individual oligomers larger than trimers inducing calcium entry as they cross the cell membrane, a result supported by imaging experiments in bilayers, and suggest that the initial molecular event that leads to neuronal damage does not involve any cellular receptors, in contrast to work performed at much higher oligomer concentrations.

Quantitative analysis of co-oligomer formation by amyloid-beta peptide isoforms

Multiple isoforms of aggregation-prone proteins are present under physiological conditions and have the propensity to assemble into co-oligomers with different properties from self-oligomers, but this process has not been quantitatively studied to date. We have investigated the amyloid-β (Aβ) peptide, associated with Alzheimer’s disease, and the aggregation of its two major isoforms, Aβ40 and Aβ42, using a statistical mechanical modelling approach in combination with in vitro single-molecule fluorescence measurements. We find that at low concentrations of Aβ, corresponding to its physiological abundance, there is little free energy penalty in forming co-oligomers, suggesting that the formation of both self-oligomers and co-oligomers is possible under these conditions. Our model is used to predict the oligomer concentration and size at physiological concentrations of Aβ and suggests the mechanisms by which the ratio of Aβ42 to Aβ40 can affect cell toxicity. An increased ratio of Aβ42 to Aβ40 raises the fraction of oligomers containing Aβ42, which can increase the hydrophobicity of the oligomers and thus promote deleterious binding to the cell membrane and increase neuronal damage. Our results suggest that co-oligomers are a common form of aggregate when Aβ isoforms are present in solution and may potentially play a significant role in Alzheimer’s disease.

CLASSIFICATION OF ANXIETY DISORDERS COMORBID WITH MAJOR DEPRESSION: COMMON OR DISTINCT INFLUENCES ON RISK?

BACKGROUND

Anxiety and depression display frequent comorbidity. Individuals with comorbid disorders also often have more extreme symptomatology than those with single disorders. This correlation between comorbidity and severity poses an interesting question: Are comorbid forms of anxiety and depression essentially just more severe versions of the pure disorders?

METHODS

In a large major depression (MD) case-control sample of individuals from the China, Oxford and VCU Experimental Research on Genetic Epidemiology project, we examined the patterns of lifetime anxiety comorbidity (including generalized anxiety disorder--GAD, panic disorder, and five phobia subtypes) among MD cases (N = 5,864) in this population. Binary and multinomial logistic regression was used to estimate associations between risk factors and outcomes including MD as well as latent class membership, which were compared using continuation ratios.

RESULTS

We found a five-class solution to fit best, and each resulting class had a distinct pattern of association with the tested risk factors. The use of continuation ratios suggests that a class characterized by high endorsement of GAD is comparable to a more severely affected "pure MD" group. The other three classes (characterized by agoraphobia, various specific phobias, and by high endorsement of all comorbid anxiety disorders, respectively) appear to differ meaningfully from MD alone.

CONCLUSIONS

Risk for MD resulting from environmental and psychosocial factors may also predispose individuals to GAD, and less consistently, other anxiety disorders. Presentations of MD with certain phobias display distinguishably different patterns of risk, however, and are therefore likely qualitatively distinct.

The similarity of the structure of DSM-IV criteria for major depression in depressed women from China, the United States and Europe

BACKGROUND

Do DSM-IV diagnostic criteria for major depression (MD) in Chinese and Western women perform in a similar manner?

METHOD

The CONVERGE study included interview-based assessments of women of Han Chinese descent with treated recurrent MD. Using Mplus software, we investigated the overall degree of between-sample measurement invariance (MI) for DSM-IV diagnostic criteria for MD in the CONVERGE sample and samples selected from four major Western studies from the USA and Europe matched to the inclusion criteria of CONVERGE. These analyses were performed one pair at a time. We then compared the results from CONVERGE paired with Western samples to those obtained when examining levels of MI between pairs of the Western samples.

RESULTS

Assuming a single factor model for the nine diagnostic criteria for MD, the level of MI based on global fit indexes observed between the CONVERGE and the four Western samples was very similar to that seen between the Western samples. Comparable results were obtained when using a two-factor structure for MI testing when applied to the 14 diagnostic criteria for MD disaggregated for weight, appetite, sleep, and psychomotor changes.

CONCLUSIONS

Despite differences in language, ethnicity and culture, DSM criteria for MD perform similarly in Chinese women with recurrent MD and comparable subjects from the USA and Europe. The DSM criteria for MD may assess depressive symptoms that are relatively insensitive to cultural and ethnic differences. These results support efforts to compare findings from depressed patients in China and Western countries.

Is there an excess of significant findings in published studies of psychotherapy for depression?

BACKGROUND

Many studies have examined the efficacy of psychotherapy for major depressive disorder (MDD) but publication bias against null results may exist in this literature. However, to date, the presence of an excess of significant findings in this literature has not been explicitly tested.

METHOD

We used a database of 1344 articles on the psychological treatment of depression, identified through systematic search in PubMed, PsycINFO, EMBASE and the Cochrane database of randomized trials. From these we identified 149 studies eligible for inclusion that provided 212 comparisons. We tested for an excess of significant findings using the method developed by Ioannidis and Trikalinos (2007), and compared the distribution of p values in this literature with the distribution in the antidepressant literature, where publication bias is known to be operating.

RESULTS

The average statistical power to detect the effect size indicated by the meta-analysis was 49%. A total of 123 comparisons (58%) reported a statistically significant difference between treatment and control groups, but on the basis of the average power observed, we would only have expected 104 (i.e. 49%) to do so. There was therefore evidence of an excess of significance in this literature (p = 0.010). Similar results were obtained when these analyses were restricted to studies including a cognitive behavioural therapy (CBT) arm. Finally, the distribution of p values for psychotherapy studies resembled that for published antidepressant studies, where publication bias against null results has already been established.

CONCLUSIONS

The small average size of individual psychotherapy studies is only sufficient to detect large effects. Our results indicate an excess of significant findings relative to what would be expected, given the average statistical power of studies of psychotherapy for major depression.

Subtypes of major depression: latent class analysis in depressed Han Chinese women

BACKGROUND

Despite substantial research, uncertainty remains about the clinical and etiological heterogeneity of major depression (MD). Can meaningful and valid subtypes be identified and would they be stable cross-culturally?

METHOD

Symptoms at their lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾ 30 years, with recurrent DSM-IV MD. Latent class analysis (LCA) was performed in Mplus. RESULTS; Using the nine DSM-IV MD symptomatic A criteria, the 14 disaggregated DSM-IV criteria and all independently assessed depressive symptoms (n = 27), the best LCA model identified respectively three, four and six classes. A severe and non-suicidal class was seen in all solutions, as was a mild/moderate subtype. An atypical class emerged once bidirectional neurovegetative symptoms were included. The non-suicidal class demonstrated low levels of worthlessness/guilt and hopelessness. Patterns of co-morbidity, family history, personality, environmental precipitants, recurrence and body mass index (BMI) differed meaningfully across subtypes, with the atypical class standing out as particularly distinct.

CONCLUSIONS

MD is a clinically complex syndrome with several detectable subtypes with distinct clinical and demographic correlates. Three subtypes were most consistently identified in our analyses: severe, atypical and non-suicidal. Severe and atypical MD have been identified in multiple prior studies in samples of European ethnicity. Our non-suicidal subtype, with low levels of guilt and hopelessness, may represent a pathoplastic variant reflecting Chinese cultural influences.

The structure of the symptoms of major depression: exploratory and confirmatory factor analysis in depressed Han Chinese women

BACKGROUND

The symptoms of major depression (MD) are clinically diverse. Do they form coherent factors that might clarify the underlying nature of this important psychiatric syndrome?

METHOD

Symptoms at lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾30 years with recurrent DSM-IV MD. Exploratory factor analysis (EFA) and confirmatoryfactor analysis (CFA) were performed in Mplus in random split-half samples.

RESULTS

The preliminary EFA results were consistently supported by the findings from CFA. Analyses of the nine DSM-IV MD symptomatic A criteria revealed two factors loading on: (i) general depressive symptoms; and (ii) guilt/suicidal ideation. Examining 14 disaggregated DSM-IV criteria revealed three factors reflecting: (i) weight/appetite disturbance; (ii) general depressive symptoms; and (iii) sleep disturbance. Using all symptoms (n = 27), we identified five factors that reflected: (i) weight/appetite symptoms; (ii) general retarded depressive symptoms; (iii) atypical vegetative symptoms; (iv) suicidality/hopelessness; and (v) symptoms of agitation and anxiety.

CONCLUSIONS

MD is a clinically complex syndrome with several underlying correlated symptom dimensions. In addition to a general depressive symptom factor, a complete picture must include factors reflecting typical/atypical vegetative symptoms, cognitive symptoms (hopelessness/suicidal ideation), and an agitated symptom factor characterized by anxiety, guilt, helplessness and irritability. Prior cross-cultural studies, factor analyses of MD in Western populations and empirical findings in this sample showing risk factor profiles similar to those seen in Western populations suggest that our results are likely to be broadly representative of the human depressive syndrome.

Cognitive trio: relationship with major depression and clinical predictors in Han Chinese women

BACKGROUND

Previous studies support Beck's cognitive model of vulnerability to depression. However, the relationship between his cognitive triad and other clinical features and risk factors among those with major depression (MD) has rarely been systematically studied.

METHOD

The three key cognitive symptoms of worthlessness, hopelessness and helplessness were assessed during their lifetime worst episode in 1970 Han Chinese women with recurrent MD. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression.

RESULTS

Compared to patients who did not endorse the cognitive trio, those who did had a greater number of DSM-IV A criteria, more individual depressive symptoms, an earlier age at onset, a greater number of episodes, and were more likely to meet diagnostic criteria for melancholia, postnatal depression, dysthymia and anxiety disorders. Hopelessness was highly related to all the suicidal symptomatology, with ORs ranging from 5.92 to 6.51. Neuroticism, stressful life events (SLEs) and a protective parental rearing style were associated with these cognitive symptoms.

CONCLUSIONS

During the worst episode of MD in Han Chinese women, the endorsement of the cognitive trio was associated with a worse course of depression and an increased risk of suicide. Individuals with high levels of neuroticism, many SLEs and high parental protectiveness were at increased risk for these cognitive depressive symptoms. As in Western populations, symptoms of the cognitive trio appear to play a central role in the psychopathology of MD in Chinese women.

A comparison of the clinical characteristics of women with recurrent major depression with and without suicidal symptomatology

BACKGROUND

The relationship between recurrent major depression (MD) in women and suicidality is complex. We investigated the extent to which patients who suffered with various forms of suicidal symptomatology can be distinguished from those subjects without such symptoms.

METHOD

We examined the clinical features of the worst episode in 1970 Han Chinese women with recurrent DSM-IV MD between the ages of 30 and 60 years from across China. Student's t tests, and logistic and multiple logistic regression models were used to determine the association between suicidality and other clinical features of MD.

RESULTS

Suicidal symptomatology is significantly associated with a more severe form of MD, as indexed by both the number of episodes and number of MD symptoms. Patients reporting suicidal thoughts, plans or attempts experienced a significantly greater number of stressful life events. The depressive symptom most strongly associated with lifetime suicide attempt was feelings of worthlessness (odds ratio 4.25, 95% confidence interval 2.9-6.3). Excessive guilt, diminished concentration and impaired decision-making were also significantly associated with a suicide attempt.

CONCLUSIONS

This study contributes to the existing literature on risk factors for suicidal symptomatology in depressed women. Identifying specific depressive symptoms and co-morbid psychiatric disorders may help improve the clinical assessment of suicide risk in depressed patients. These findings could be helpful in identifying those who need more intense treatment strategies in order to prevent suicide.

Meta-analysis indicates that common variants at the DISC1 locus are not associated with schizophrenia

Several polymorphisms in the Disrupted-in-Schizophrenia-1 (DISC1) gene are reported to be associated with schizophrenia. However, to date, there has been little effort to evaluate the evidence for association systematically. We carried out an imputation-driven meta-analysis, the most comprehensive to date, using data collected from 10 candidate gene studies and three genome-wide association studies containing a total of 11 626 cases and 15 237 controls. We tested 1241 single-nucleotide polymorphisms in total, and estimated that our power to detect an effect from a variant with minor allele frequency >5% was 99% for an odds ratio of 1.5 and 51% for an odds ratio of 1.1. We find no evidence that common variants at the DISC1 locus are associated with schizophrenia.

Patterns of co-morbidity with anxiety disorders in Chinese women with recurrent major depression

BACKGROUND

Studies conducted in Europe and the USA have shown that co-morbidity between major depressive disorder (MDD) and anxiety disorders is associated with various MDD-related features, including clinical symptoms, degree of familial aggregation and socio-economic status. However, few studies have investigated whether these patterns of association vary across different co-morbid anxiety disorders. Here, using a large cohort of Chinese women with recurrent MDD, we examine the prevalence and associated clinical features of co-morbid anxiety disorders.

METHOD

A total of 1970 female Chinese MDD patients with or without seven co-morbid anxiety disorders [including generalized anxiety disorder (GAD), panic disorder, and five phobia subtypes] were ascertained in the CONVERGE study. Generalized linear models were used to model association between co-morbid anxiety disorders and various MDD features.

RESULTS

The lifetime prevalence rate for any type of co-morbid anxiety disorder is 60.2%. Panic and social phobia significantly predict an increased family history of MDD. GAD and animal phobia predict an earlier onset of MDD and a higher number of MDD episodes, respectively. Panic and GAD predict a higher number of DSM-IV diagnostic criteria. GAD and blood-injury phobia are both significantly associated with suicidal attempt with opposite effects. All seven co-morbid anxiety disorders predict higher neuroticism.

CONCLUSIONS

Patterns of co-morbidity between MDD and anxiety are consistent with findings from the US and European studies; the seven co-morbid anxiety disorders are heterogeneous when tested for association with various MDD features.

Perceived parenting and risk for major depression in Chinese women

BACKGROUND

In Western countries, a history of major depression (MD) is associated with reports of received parenting that is low in warmth and caring and high in control and authoritarianism. Does a similar pattern exist in women in China?

METHOD

Received parenting was assessed by a shortened version of the Parental Bonding Instrument (PBI) in two groups of Han Chinese women: 1970 clinically ascertained cases with recurrent MD and 2597 matched controls. MD was assessed at personal interview.

RESULTS

Factor analysis of the PBI revealed three factors for both mothers and fathers: warmth, protectiveness, and authoritarianism. Lower warmth and protectiveness and higher authoritarianism from both mother and father were significantly associated with risk for recurrent MD. Parental warmth was positively correlated with parental protectiveness and negatively correlated with parental authoritarianism. When examined together, paternal warmth was more strongly associated with lowered risk for MD than maternal warmth. Furthermore, paternal protectiveness was negatively and maternal protectiveness positively associated with risk for MD.

CONCLUSIONS

Although the structure of received parenting is very similar in China and Western countries, the association with MD is not. High parental protectiveness is generally pathogenic in Western countries but protective in China, especially when received from the father. Our results suggest that cultural factors impact on patterns of parenting and their association with MD.

Childhood sexual abuse and the risk for recurrent major depression in Chinese women

BACKGROUND

Studies in Western countries have repeatedly shown that women with a history of childhood sexual abuse (CSA) are at increased risk for developing major depression (MD). Would this relationship be found in China?

METHOD

Three levels of CSA (non-genital, genital, and intercourse) were assessed by self-report in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression and regression coefficients by linear or Poisson regression.

RESULTS

Any form of CSA was significantly associated with recurrent MD [OR 3.26, 95% confidence interval (CI) 1.95-5.45]. This association strengthened with increasing CSA severity: non-genital (OR 2.47, 95% CI 1.17-5.23), genital (OR 2.77, 95% CI 1.32-5.83) and intercourse (OR 13.35, 95% CI 1.83-97.42). The association between any form of CSA and MD remained significant after accounting for parental history of depression, childhood emotional neglect (CEN), childhood physical abuse (CPA) and parent-child relationship. Among the depressed women, those with CSA had an earlier age of onset, longer depressive episodes and an increased risk for generalized anxiety disorder (GAD; OR 1.92, 95% CI 1.39-2.66) and dysthymia (OR 2.16, 95% CI 1.52-3.09).

CONCLUSIONS

In Chinese women CSA is strongly associated with MD and this association increases with greater severity of CSA. Depressed women with CSA have an earlier age of onset, longer depressive episodes and increased co-morbidity with GAD and dysthymia. Although reporting biases cannot be ruled out, our results are consistent with the hypothesis that, as in Western countries, CSA substantially increases the risk for MD in China.

Cytoarchitectural disruption of the superior colliculus and an enlarged acoustic startle response in the Tuba1a mutant mouse

The Jenna mutant mouse harbours an S140G mutation in Tuba1a that impairs tubulin heterodimer formation resulting in defective neuronal migration during development. The consequence of decreased neuronal motility is a fractured pyramidal cell layer in the hippocampus and wave-like perturbations in the cerebral cortex. Here, we extend our characterisation of this mouse investigating the laminar architecture of the superior colliculus (SC). Our results reveal that the structure of the SC in mutant animals is intact; however, it is significantly thinner with an apparent fusion of the intermediate grey and white layers. Birthdate labelling at E12.5 and E13.5 showed that the S140G mutation impairs the radial migration of neurons in the SC. A quantitative assessment of neuronal number in adulthood reveals a massive reduction in postmitotic neurons in mutant animals, which we attribute to increased apoptotic cell death. Consistent with the role of the SC in modulating sensorimotor gating, and the circuitry that modulates this behaviour, we find that Jenna mutants exhibit an exaggerated acoustic startle response. Our results highlight the importance of Tuba1a for correct neuronal migration and implicate postnatal apoptotic cell death in the pathophysiological mechanisms underlying the tubulinopathies.

Association of the 5- HTTLPR genotype and unipolar depression: a meta-analysis

BACKGROUND

We sought to ascertain the strength of evidence for association between the 5-HTTLPR polymorphism and unipolar depression.

METHOD

We applied meta-analytic techniques to data from relevant published studies, and obtained an estimate of the likely magnitude of effect of any association. We also tested for possible publication bias, and explored the impact of various study design characteristics on the magnitude of the observed effect size.

RESULTS

Meta-analysis indicated evidence of a small but statistically significant association between the 5-HTTLPR polymorphism and unipolar depression [odds ratio (OR) 1.08, 95% confidence interval (CI) 1.03-1.12]. This remained significant when data from samples of European and East Asian ancestry were analyzed separately. In all cases there was evidence of significant between-study heterogeneity, although the observed associations were robust to the application of a random-effects framework.

CONCLUSIONS

Our results support the presence of a small effect of a polymorphism in the serotonin transporter promoter on susceptibility to depression. However, we caution that it is possible that the effect has an artifactual basis, rather than a biological origin.

Novel alpha haemoglobin haplotypes in horses

Four minor haplotypes that produce abnormal haemoglobin phenotypes in horses have been characterized. Two of them, AIIb and V, are copy number variants with, respectively, one and three alpha genes instead of the normal complement of two. The AIIa and C haplotypes, on the other hand, each have two alpha genes but, as a result of probable gene conversions, they now encode identical, though haplotype specific, globins. Two out of 60 unrelated and phenotypically normal horses studied had an unusual triplicated rearrangement in the embryonic zeta-gene locus. Each of these variants appears to have been produced by aberrant recombination events.

Mucoid impaction secondary to mucin-producing metastatic adenocarcinoma of the cervix

Endobronchial metastases are an uncommon complication of malignant tumours. The vast majority are secondary to carcinoma of the breast, colorectum and kidney, or to melanoma. Occasionally, endobronchial tumours can result in partial or complete bronchial obstruction. Here, we describe an uncommon case of endobronchial metastasis of adenocarcinoma of the cervix causing mucoid impaction owing to mucous production by the tumour cells.

A whole genome association study of neuroticism using DNA pooling

We describe a multistage approach to identify single nucleotide polymorphisms (SNPs) associated with neuroticism, a personality trait that shares genetic determinants with major depression and anxiety disorders. Whole genome association with 452 574 SNPs was performed on DNA pools from approximately 2000 individuals selected on extremes of neuroticism scores from a cohort of 88 142 people from southwest England. The most significant SNPs were then genotyped on independent samples to replicate findings. We were able to replicate association of one SNP within the PDE4D gene in a second sample collected by our laboratory and in a family-based test in an independent sample; however, the SNP was not significantly associated with neuroticism in two other independent samples. We also observed an enrichment of low P-values in known regions of copy number variations. Simulation indicates that our study had approximately 80% power to identify neuroticism loci in the genome with odds ratio (OR)>2, and approximately 50% power to identify small effects (OR=1.5). Since we failed to find any loci accounting for more than 1% of the variance, the heritability of neuroticism probably arises from many loci each explaining much less than 1%. Our findings argue the need for much larger samples than anticipated in genetic association studies and that the biological basis of emotional disorders is extremely complex.

Pulmonary actinomycosis complicating infliximab therapy for Crohn's disease

The use of anti-tumour necrosis factor (TNF) agents has expanded significantly over the past few years, particularly for rheumatological diseases and Crohn's disease. A number of associated opportunistic infections have been observed as a result of suppression of T cell-mediated immunity, the most frequent being tuberculosis. We report the first case of pulmonary actinomycosis in a patient receiving regular infusions of infliximab, an anti-TNF agent, for Crohn's disease.

Soft tissue tumours and mass-like lesions of the chest wall: a pictorial review of CT and MR findings

Soft tissue tumours and tumour-like lesions of the chest wall are uncommon. The purpose of this pictorial essay is to describe the imaging findings of chest wall soft tissue tumours and tumour-like lesions. We searched the radiological and pathological archive at our institution retrospectively and reviewed the literature on soft tissue tumours of the chest wall. Common chest wall soft tissue tumours and mass-like lesions include peripheral nerve tumours, lipomas, liposarcomas, haemangiomas, elastofibromas, metastases, lymphoma and abscesses. Other lesions encountered include desmoid tumours and malignant fibrous histiocytoma. Many have distinctive radiological findings or occur in specific locations, allowing a specific radiological diagnosis to be suggested.

Association of the DRD2 gene Taq1A polymorphism and alcoholism: a meta-analysis of case-control studies and evidence of publication bias

We investigated the association of the dopamine D2 receptor (DRD2) Taq1A polymorphism and alcoholism, using meta-analytic techniques, and specifically undertook an investigation of possible publication bias. Potential publication bias represents a genuine risk to the integrity of published research, but its impact has rarely been documented. We observed a small effect of the DRD2 Taq1A polymorphism on risk of alcoholism, indicating increased alcoholism in individuals possessing the A1 allele of the Taq1A polymorphism (OR=1.21, 95% CI 1.13-1.30, P<0.001). This association remained significant when data from samples of European and East Asian ancestry were analyzed separately. We did not find evidence for association in high-severity alcoholism compared to low-severity alcoholism. Removing the first published study significantly reduced the magnitude of the pooled effect size estimate, although the association remained significant. In addition, we observed evidence for possible publication bias and for the strength of individual study effect size to be inversely related to year of publication. These results support the association of the DRD2 Taq1A polymorphism with alcoholism. This conclusion is qualified by the possibility of publication bias in the literature and the observed between-study heterogeneity, which indicates that the observed association may differ in strength between populations or may not exist at all in some populations.

Under-reporting of infectious gastrointestinal illness in British Columbia, Canada: who is counted in provincial communicable disease statistics?

Under-reporting of infectious gastrointestinal illness (IGI) in British Columbia, Canada was calculated using simulation modelling, accounting for the uncertainty and variability of input parameters. Factors affecting under-reporting were assessed during a cross-sectional randomized telephone survey. For every case of IGI reported to the province, a mean of 347 community cases occurred (5th and 95th percentile estimates ranged from 181 to 611 community cases, respectively). Vomiting [odds ratio (OR) 2.15, 95% confidence interval (CI) 1.03-4.49] and antibiotic use in the previous 28 days (OR 3.59, 95% CI 1.17-10.97) significantly predicted health-care visits in a logistic regression model. In bivariate analyses, physicians were significantly less likely to request stool samples from patients with vomiting (RR 0.09, 95% CI 0.01-0.65) and patients of North American as opposed to non-North American cultural groups (RR 0.38, 95% CI 0.15-0.96). Physicians were more likely to request stool samples from older patients (P=0.003), patients with fewer household members (P=0.002) and those who reported anti-diarrhoeal use following illness (RR 3.33, 95% CI 1.32-8.45). People with symptoms of vomiting were under-represented in provincial communicable disease statistics. Differential degrees of under-reporting must be understood before biased surveillance data can be adjusted.

Malignant chest wall neoplasms of bone and cartilage: a pictorial review of CT and MR findings

Malignant tumours of the chest wall are uncommon. The purpose of this pictorial essay is to describe the CT and MRI findings of malignant neoplasms affecting the bony skeleton of the chest wall and the costal cartilages. The most common primary malignant neoplasms involving the bony skeleton of the chest wall are chondrosarcoma, osteosarcoma and Ewing's sarcoma/primitive neuroectodermal tumour. Metastases, multiple myeloma and invasive primary lung cancer are the most frequent secondary lesions. We performed a retrospective review of the radiology and pathology archive at our institution from 1 July 2000 to 31 December 2004 and identified 31 of these lesions. Several of these tumours have distinctive radiological features, allowing a confident radiological diagnosis to be suggested.

Association of the NRG1 gene and schizophrenia: a meta-analysis

We investigated the association of the NRG1 gene and schizophrenia using meta-analytic techniques, combining all published data while restricting our analysis to studies investigating the most commonly reported single marker (SNP8NRG221533). We also investigated whether ancestry (European vs East Asian) and study design (family-based vs case-control) moderated any association. We found no evidence for an association of SNP8NRG221533 with schizophrenia, and significant between-study heterogeneity, which persisted when family-based studies were combined separately. However, when haplotype-based P-values were combined, there was evidence in support of an association of NRG1 with schizophrenia, and no evidence of between-study heterogeneity. Our meta-analysis provides support for the association of NRG1 with schizophrenia, but indicates that firmly establishing the role of NRG1 gene in schizophrenia by genetic association requires much larger sample sizes than have hitherto been reported. Association analyses and replications should take place at the level of the gene, rather than at the level of SNP, haplotype, or functional variant. Meta-analysis would then be carried out on the basis of the combination of P-values.

Rgs 2 gene polymorphisms as modulators of anxiety in humans?

Rgs2 (regulator of G-protein signalling 2) gene recently was reported as a quantitative trait gene for anxious behaviour in mice and male Rgs2 knockout mice have been shown to be more anxious than wildtype mice. Therefore we investigated four non-coding single nucleotide polymorphisms in a sample of 173 patients with panic disorder and 173 matched controls of German descent. At the genotype level all four SNPs were associated with panic disorder (p = 0.02-0.05). At the haplotype level the strongest association was observed for a haplotype containing SNP3 and SNP 4 (subgroup men and men with agoraphobia: p = 0.01 and 0.03). This points towards a functional polymorphism at the 3' end of the gene. Our results support the hypothesis that variations of the Rgs2 gene play a role also for the development of anxiety in humans.

Using progenitor strain information to identify quantitative trait nucleotides in outbred mice

We have developed a fast and economical strategy for dissecting the genetic architecture of quantitative trait loci at a molecular level. The method uses two pieces of information: mapping data from crosses that involve more than two inbred strains and sequence variants in the progenitor strains within the interval containing a quantitative trait locus (QTL). By testing whether the strain distribution pattern in the progenitor strains is consistent with the observed genetic effect of the QTL we can assign a probability that any sequence variant is a quantitative trait nucleotide (QTN). It is not necessary to genotype the animals except at a skeleton of markers; the genotypes at all other polymorphisms are estimated by a multipoint analysis. We apply the method to a 4.8-Mb region on mouse chromosome 1 that contains a QTL influencing anxiety segregating in a heterogeneous stock and show that, under the assumption that a single QTN is present and lies in a region conserved between the human and mouse genomes, it is possible to reduce the number of variants likely to be the quantitative trait nucleotide from many thousands to <20.

Lack of association of the COMT (Val158/108 Met) gene and schizophrenia: a meta-analysis of case-control studies

There is strong evidence for a genetic contribution to schizophrenia, but the contribution of individual candidate genes remains uncertain. We attempted to replicate a recent meta-analysis that reported an association of the catechol O-methyltransferase (COMT) Val allele with schizophrenia, and suggested that this effect may be moderated by ancestry. We included reports published subsequent to the original meta-analysis, and included a formal test of the moderating effect of ancestry in order to test whether the association operates differently in populations of European ancestry compared to populations of Asian ancestry. A corrected P-value for the 5% significance threshold was employed where appropriate, using Bonferroni's method, and studies that demonstrated departure from Hardy-Weinberg equilibrium among controls were excluded. When all studies were included in a meta-regression, there was evidence for a significant association of COMT Val allele frequency with schizophrenia case status and a significant main effect of ancestry. The interaction of COMT Val allele frequency and ancestry was also significant. However, when only studies that reported allele frequencies that did not depart significantly from Hardy-Weinberg equilibrium among controls were included, these effects were no longer significant. The results of our meta-analysis do not support an association between the COMT Val allele and schizophrenia case status, and do not support recent claims that this association may be moderated by ancestry.

Does measurement instrument moderate the association between the serotonin transporter gene and anxiety-related personality traits? A meta-analysis

We attempted to replicate the findings of two recent meta-analyses that personality inventory moderates the association between the serotonin transporter gene and anxiety-related traits. A total of 24 studies contributed to the meta-analysis, of which three reported genotype frequencies that deviated from Hardy-Weinberg (HW) equilibrium. We found some support for the view that results depend on the type of questionnaire used, although in a direction opposite to that previously reported. Contrasts between the S/S and L/L groups were significant for TCI/TPQ harm avoidance studies (P=0.0024) but not NEO neuroticism (P=0.9757). When studies not in HW equilibrium were excluded the TCI/TPQ result for the S/S genotype still exceeded our 5% threshold, although with reduced significance (P=0.0082), and the NEO result remained nonsignificant (P=0.9109). While we cannot rule out an association between the 5HTT gene and anxiety-related traits, particularly for TCI/TPQ harm avoidance, our findings do indicate that the effect, if present, is small. Our results emphasise the importance of complete ascertainment of studies and the identification of relevant sources of heterogeneity.

Interpretation of Transbronchial Lung Biopsies from Lung Transplant Recipients:Inter- and Intraobserver Agreement

BACKGROUND: Transbronchial lung biopsy results are crucial for the management of lung transplant recipients. Little information is available regarding the reliability and reproducibility of the interpretation of transbronchial lung biopsies.

OBJECTIVE: To examine the inter-reader variability between two lung pathologists with expertise in lung transplantation.

METHODS: Fifty-nine transbronchial lung biopsy specimens were randomly selected. Active infection had been excluded in all cases. The original interpretations (as per the Lung Rejection Study Group) for acute rejection grade included 19 biopsies scored as A0 (none), 14 scored as A1 (minimal), 12 as A2 (mild), 11 as A3 (moderate) and three as A4 (severe). The pathologists worked independently without clinical information or knowledge of the original interpretation. The specimens were graded using the Lung Rejection Study Group criteria for acute rejection (grades A0 to A4), airway inflammation (grades B0 to B4) and bronchiolitis obliterans (C0 absent and C1 present). Between-reader agreement for each category was analyzed using a Kappa statistic.

RESULTS: Because many transplant specialists initiate augmented immunosuppression with biopsy grades of A2 or higher, results for each reader were dichotomized as A0/A1 versus A2/A3/A4. Using this dichotomy, there was only moderate agreement (kappa 0.470, P<0.001) between readers. For categories B and C, the results were dichotomized for the absence or presence of airway inflammation and bronchiolitis obliterans, respectively. The level of agreement between readers was fair for category B (kappa 0.333, P=0.014) and poor for category C (kappa 0.166, P=0.108). The intrareader agreement for acute rejection was substantial (kappa 0.795, P=0.0001; kappa 0.676, P=0.0001).

CONCLUSIONS: Because the agreement between expert pathologists is only modest, optimum clinical decision-making requires that transbronchial lung biopsy results be used in an integrated clinical context.

p63 Expression in Lung Carcinoma

p63 is a recently discovered member of the p53 family that has been shown to be important in the development of epithelial tissues. p63 may also play a role in squamous cell carcinomas of the lung, head and neck, and cervix, and its expression is increased in these tumors. The purpose of this study was to investigate the expression of p63 in a broad spectrum of histologic types of lung tumors. A total of 441 cases of primary lung tumors with follow-up data were identified, and the paraffin-embedded tissue blocks were used to construct a duplicate core tissue microarray. After review of the tissue cores, 408 cases, consisting of 123 squamous cell carcinomas, 93 adenocarcinomas, 68 large cell carcinomas, 68 classic carcinoids, 31 atypical carcinoids, 11 large cell neuroendocrine carcinomas, and 14 small cell carcinomas, were adequate for analysis. Immunohistochemistry was performed at 2 different laboratories using monoclonal antibody 4A4 to detect the expression of p63, using different staining protocols. p53 expression was also studied with immunohistochemistry using monoclonal antibody DO-7. Kaplan-Meier curves were plotted to compare the survival of p63-expressing versus nonexpressing tumors. A large proportion of squamous cell carcinomas expressed p63 (96.9%), most showing strong positive nuclear immunoreactivity. Expression in other nonsmall cell lung cancers was also present. Thirty percent of adenocarcinomas and 37% of large cell carcinomas showed p63 expression. In the neuroendocrine tumors, an increasing proportion of tumors stained for p63 as tumor grade increased; 1.9% of classic carcinoids, 30.8% of atypical carcinoids, 50% of large cell neuroendocrine carcinomas, and 76.9% of small cell carcinomas were positive. Approximately half of the positively staining neuroendocrine cases showed strong staining. Expression of p63 was of prognostic significance in neuroendocrine tumors (P < 0.0001), with higher-grade tumors more likely to express p63. Correlation between p63 and p53 expression was not observed (P = 0.18) in nonsmall cell lung cancer; however, a significant correlation between the 2 markers was found in neuroendocrine tumors (P < 0.0001). p63 staining was repeated with a different staining protocol, yielding similar results overall but a lower percentage of positive cases (34.2% vs. 48.4% of tumors positive). In conclusion, p63 expression is consistently expressed in squamous cell carcinoma in the lung, but is also expressed in a subset of adenocarcinomas and large cell carcinomas. Pulmonary neuroendocrine tumors also show p63 staining in some instances, particularly in higher-grade tumors, and the majority of small cell carcinomas are p63-positive. These results suggest that p63 may be involved in oncogenesis in a broader range of tumors than was previously thought.