Polygenic risk and hostile environments: Links to stable and dynamic antisocial behaviors across adolescence

Adverse environments are linked to elevated youth antisocial behavior. However, this relation is thought to depend, in part, on genetic susceptibility. The present study investigated whether polygenic risk for antisociality moderates relations between hostile environments and stable as well as dynamic antisocial behaviors across adolescence. We derived two antisocial-linked polygenic risk scores (PRS) (N = 721) based on previous genome-wide association studies. Forms of antisocial behavior (nonaggressive conduct problems, physical aggression, social aggression) and environmental hostility (harsh parenting and school violence) were assessed at age 13, 15, and 17 years. Relations to individual differences stable across adolescence (latent stability) vs. time-specific states (timepoint residual variance) of antisocial behavior were assessed via structural equation models. Higher antisocial PRS, harsh parenting, and school violence were linked to stable elevations in antisocial behaviors across adolescence. We identified a consistent polygenic-environment interaction suggestive of differential susceptibility in late adolescence. At age 17, harsher parenting was linked to higher social aggression in those with higher antisocial PRS, and lower social aggression in those with lower antisocial PRS. This suggests that genetics and environmental hostility relate to stable youth antisocial behaviors, and that genetic susceptibility moderates home environment-antisocial associations specifically in late adolescence.

A232 RISK OF TOTAL METACHRONOUS ADVANCED NEOPLASIA AT SURVEILLANCE COLONOSCOPY AFTER DETECTION OF SERRATED LESIONS: A MATCHED COHORT STUDY

Background

Serrated lesions (SLs), including sessile serrated lesions (SSL) and traditional serrated adenomas (TSA) have become subject of increased interest for their role as CRC precursors.

Purpose

Study aim was to evaluate the risk to develop total metachronous advanced neoplasia (T-MAN) at follow-up in patients with index SL compared to a matched cohort without SL.

Method

Patients 45-74y with SLs were identified through pathology database search. SL patients were matched 2:1 by sex; age; synchronous polyps (high-risk adenoma [HRA], low-risk adenoma [LRA], no-adenoma); timing of index, to patients without SL. Primary outcome was risk of T-MAN (advanced adenoma or high-risk SL) at follow-up. Secondary outcomes included risk of T-MAN stratified by synchronous polyps and SL characteristics.

Result(s)

1425 patients were included (475 patients, 642 SLs; 950 controls (mean follow-up 2.9 vs 3.9y). The SL group had greater risk of T-MAN compared to the non-SL group [Hazard-ratio (HR)=6.12 (95%confidence-interval (CI)3.91-9.58)]. Patients with SL+HRA had higher risk of T-MAN compared to HRA alone [HR=2.62 (95%CI 1.45-4.71)], as well as patients with SL+LRA compared to LRA alone [HR=7.03 (95%CI 2.78-18.44)], and SL without adenoma compared to no-adenoma [HR=14.87 (95%CI 6.51-33.95)]. Presence of proximal SSL (HR=9.30), large SSL (HR=17.87) and proximal large SSL (HR=24.99), but not distal SSL, was associated with greater risk for T-MAN.

Conclusion(s)

Patients with SLs are at greater risk for developing T-MAN regardless of synchronous adenomas. Patients with SL and HRA, and those with large or proximal SSLs appear to be at greatest risk for T-MAN.

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Disclosure of Interest

R. Djinbachian Grant / Research support from: Grant from the American College of Gastroenterology for the conduction of this project, M.-L. Lafontaine: None Declared, J. Anderson: None Declared, H. Pohl: None Declared, T. Dufault: None Declared, M. Boivin: None Declared, M. Bouin: None Declared, D. von Renteln Grant / Research support from: Daniel von Renteln is supported by a “Fonds de Recherche du Québec Santé” (FRQS) career development award and has received research funding from ERBE, Ventage, Pendopharm, Fujifilm, and Pentax., Consultant of: Boston Scientific and Pendopharm,

A biallelic loss of function variant in HORMAD1 within a large consanguineous Turkish family is associated with spermatogenic arrest

STUDY QUESTION

Can the analysis of a large Turkish consanguineous family via whole exome sequencing (WES) identify novel causative genetic variation responsible for nonobstructive azoospermia (NOA) characterized by arrest at primary spermatocyte stage?

SUMMARY ANSWER

WES analysis revealed a homozygous nonsense variant in HORMAD1 in three affected brothers of a Turkish family.

WHAT IS KNOWN ALREADY

Studying patient cohorts in small or large consanguineous families using high-throughput sequencing allows the identification of genetic causes of different pathologies, including infertility. Over the last two decades, a number of genes involved in human male infertility have been discovered, but only 14 genes have been identified as being at least moderately linked to isolated NOA or oligozoospermia in men.

STUDY DESIGN, SIZE, DURATION

The study included a Turkish family comprising three brothers with NOA. Two brothers had a normal karyotype, normal hormonal levels and no Yq microdeletion. The testicular histopathology analysis revealed the complete arrest of spermatogenesis at the primary spermatocyte stage.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We recruited a consanguineous Turkish family where parents were first-degree cousins and had seven children; three sons who had NOA, two sons who were fertile and two daughters for whom no information was available. Saliva samples from the index patient, his two affected brothers, parents and two nonaffected brothers (seven samples in total) were collected. Prior to WES, the index patient underwent targeted genetic testing using an infertility panel, which includes 133 infertility genes. No pathogenic variations were identified. WES was then performed on the DNA of the seven family members available. Bioinformatics analysis was performed using an in-house pipeline. Detected variants were scored and ranked, and copy number variants were called and annotated.The consequences of mutation on protein expression and localization were investigated by cell transfection followed by immunofluorescence or immunoblotting.

MAIN RESULTS AND THE ROLE OF CHANCE

WES revealed a homozygous nonsense variant chr1:150675797G>A; HORMAD1 (NM_032132.5): c.1021C>T, p.Gln341* in exon 13, which was confirmed in all three affected brothers. HORMAD1 encodes the HORMA domain-containing protein 1. The parents as well as the two fertile brothers were carriers of this variant. This variant may lead to the production of a truncated protein lacking the nuclear localization signal; therefore, human cells were transfected with the wild-type and mutated form, in fusion with green fluorescent protein. Immunoblotting experiments confirmed the production of a truncated HORMAD1 protein, and immunofluorescence microscopy revealed that the mutated protein displayed cytoplasmic localization while the wild type protein located to the nucleus. Altogether, our findings validate HORMAD1 as an essential genetic factor in the meiotic process in human.

LIMITATIONS, REASONS FOR CAUTION

According to one scoring system used to evaluate the clinical validity of male infertility genes, this study would classify HORMAD1 as displaying limited clinical evidence of being involved in male infertility. However, such a score is the maximum possible when only one family is analyzed and the addition of one patient showing a pathogenic or likely pathogenic variant would immediately change this classification to 'moderate'. Thus, this report should prompt other researchers to screen patients with NOA for this genetic variant.

WIDER IMPLICATIONS OF THE FINDINGS

Identification of new genetic factors involved in the human meiosis process will contribute to an improvement of our knowledge at the basic level, which in turn will allow the management of better care for infertile patients. Since Hormad1-/- knock-out female mice are also infertile, HORMAD1 could also be involved in human female infertility. Our findings have direct implications for the genetic counseling of patients and their family members.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by Fondation Maladies Rares (High Throughput Sequencing and Rare Diseases-2018, 'GenOmics of rare diseases'). The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Associations between epigenetic aging and childhood peer victimization, depression, and suicidal ideation in adolescence and adulthood: A study of two population-based samples

Background: Prior studies indicate that peer victimization (including bullying) is associated with higher risk for depression and suicidal ideation across the life course. However, molecular mechanisms underlying these associations remain unclear. This two-cohort study proposes to test whether epigenetic aging and pace of aging, as well as a DNA methylation marker of responsive to glucocorticoids, are associated to childhood peer victimization and later depressive symptoms, or suicidal ideation. Methods: Cohort 1: Epigenome-wide DNA methylation (EPIC array) was measured in saliva collected when participants were 10.47 years (standard deviation = 0.35) in a subsample of the Quebec Longitudinal Study of Child Development (QLSCD, n = 149 participants), with self-reported peer victimization at 6-8 years, depressive symptoms (mean symptoms, and dichotomized top 30% symptoms) and suicidal ideation at 15-17 years. Cohort 2: Epigenome-wide DNA methylation (EPIC array) was measured in blood collected from participants aged 45.13 years (standard deviation = 0.37) in a subsample of the 1958 British Birth cohort (1958BBC, n = 238 participants) with information on mother-reported peer victimization at 7-11 years, self-reported depressive symptoms at 50 years, and suicidal ideation at 45 years. Five epigenetic indices were derived: three indicators of epigenetic aging [Horvath's pan-tissue (Horvath1), Horvath's Skin-and-Blood (Horvath2), Pediatric-Buccal-Epigenetic age (PedBE)], pace of aging (DunedinPACE), and stress response reactivity (Epistress). Results: Peer victimization was not associated with the epigenetic indices in either cohort. In the QLSCD, higher PedBE epigenetic aging and a slower pace of aging as measured by DunedinPACE predicted higher depressive symptoms scores. In contrast, neither the Horvath1, or Horvath2 epigenetic age estimates, nor the Epistress score were associated with depressive symptoms in either cohort, and none of the epigenetic indices predicted suicidal ideation. Conclusion: The findings are consistent with epigenome-wide and candidate gene studies suggesting that these epigenetic indices did not relate to peer victimization, challenging the hypothesis that cumulative epigenetic aging indices could translate vulnerability to depressive symptoms and suicidal ideation following peer victimization. Since some indices of epigenetic aging and pace of aging signaled higher risk for depressive symptoms, future studies should pursue this investigation to further evaluate the robustness and generalization of these preliminary findings.

Trinucleotide CGG Repeat Diseases: An Expanding Field of Polyglycine Proteins?

Microsatellites are repeated DNA sequences of 3–6 nucleotides highly variable in length and sequence and that have important roles in genomes regulation and evolution. However, expansion of a subset of these microsatellites over a threshold size is responsible of more than 50 human genetic diseases. Interestingly, some of these disorders are caused by expansions of similar sequences, sizes and localizations and present striking similarities in clinical manifestations and histopathological features, which suggest a common mechanism of disease. Notably, five identical CGG repeat expansions, but located in different genes, are the causes of fragile X-associated tremor/ataxia syndrome (FXTAS), neuronal intranuclear inclusion disease (NIID), oculopharyngodistal myopathy type 1 to 3 (OPDM1-3) and oculopharyngeal myopathy with leukoencephalopathy (OPML), which are neuromuscular and neurodegenerative syndromes with overlapping symptoms and similar histopathological features, notably the presence of characteristic eosinophilic ubiquitin-positive intranuclear inclusions. In this review we summarize recent finding in neuronal intranuclear inclusion disease and FXTAS, where the causing CGG expansions were found to be embedded within small upstream ORFs (uORFs), resulting in their translation into novel proteins containing a stretch of polyglycine (polyG). Importantly, expression of these polyG proteins is toxic in animal models and is sufficient to reproduce the formation of ubiquitin-positive intranuclear inclusions. These data suggest the existence of a novel class of human genetic pathology, the polyG diseases, and question whether a similar mechanism may exist in other diseases, notably in OPDM and OPML.

Translation of GGC repeat expansions into a toxic polyglycine protein in NIID defines a novel class of human genetic disorders: The polyG diseases

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease characterized by the presence of intranuclear inclusions of unknown origin. NIID is caused by an expansion of GGC repeats in the 5′ UTR of the NOTCH2NLC (N2C) gene. We found that these repeats are embedded in a small upstream open reading frame (uORF) (uN2C), resulting in their translation into a polyglycine-containing protein, uN2CpolyG. This protein accumulates in intranuclear inclusions in cell and mouse models and in tissue samples of individuals with NIID. Furthermore, expression of uN2CpolyG in mice leads to locomotor alterations, neuronal cell loss, and premature death of the animals. These results suggest that translation of expanded GGC repeats into a novel and pathogenic polyglycine-containing protein underlies the presence of intranuclear inclusions and neurodegeneration in NIID.

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NIID is a neurodegenerative disease caused by expansion of GGC repeats in NOTCH2NLC

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These GGC repeats are translated into a polyglycine (polyG) protein

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The polyG protein is toxic and forms intranuclear inclusions in cells and animals

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Similarities between FXTAS and NIID define a new set of disorders: polyG diseases

Reduced autophagy upon C9ORF72 loss synergizes with dipeptide repeat protein toxicity in G4C2 repeat expansion disorders

Expansion of G4C2 repeats within the C9ORF72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Such repeats lead to decreased expression of the autophagy regulator C9ORF72 protein. Furthermore, sense and antisense repeats are translated into toxic dipeptide repeat (DPR) proteins. It is unclear how these repeats are translated, and in which way their translation and the reduced expression of C9ORF72 modulate repeat toxicity. Here, we found that sense and antisense repeats are translated upon initiation at canonical AUG or near‐cognate start codons, resulting in polyGA‐, polyPG‐, and to a lesser degree polyGR‐DPR proteins. However, accumulation of these proteins is prevented by autophagy. Importantly, reduced C9ORF72 levels lead to suboptimal autophagy, thereby impairing clearance of DPR proteins and causing their toxic accumulation, ultimately resulting in neuronal cell death. Of clinical importance, pharmacological compounds activating autophagy can prevent neuronal cell death caused by DPR proteins accumulation. These results suggest the existence of a double‐hit pathogenic mechanism in ALS/FTD, whereby reduced expression of C9ORF72 synergizes with DPR protein accumulation and toxicity.

Associations between birth size and later height from infancy through adulthood: An individual based pooled analysis of 28 twin cohorts participating in the CODATwins project

BACKGROUND

There is evidence that birth size is positively associated with height in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment.

AIM

To analyze the associations of birth weight, length and ponderal index with height from infancy through adulthood within mono- and dizygotic twin pairs, which provides insights into the role of genetic and environmental individual-specific factors.

METHODS

This study is based on the data from 28 twin cohorts in 17 countries. The pooled data included 41,852 complete twin pairs (55% monozygotic and 45% same-sex dizygotic) with information on birth weight and a total of 112,409 paired height measurements at ages ranging from 1 to 69 years. Birth length was available for 19,881 complete twin pairs, with a total of 72,692 paired height measurements. The association between birth size and later height was analyzed at both the individual and within-pair level by linear regression analyses.

RESULTS

Within twin pairs, regression coefficients showed that a 1-kg increase in birth weight and a 1-cm increase in birth length were associated with 1.14-4.25 cm and 0.18-0.90 cm taller height, respectively. The magnitude of the associations was generally greater within dizygotic than within monozygotic twin pairs, and this difference between zygosities was more pronounced for birth length.

CONCLUSION

Both genetic and individual-specific environmental factors play a role in the association between birth size and later height from infancy to adulthood, with a larger role for genetics in the association with birth length than with birth weight.

Potential pathogenic mechanisms underlying Fragile X Tremor Ataxia Syndrome: RAN translation and/or RNA gain-of-function?

Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited neurodegenerative disease caused by an expansion of 55-200 CGG repeats located in the FMR1 gene. The main clinical and neuropathological features of FXTAS are progressive intention tremor and gait ataxia associated with brain atrophy, neuronal cell loss and presence of ubiquitin-positive intranuclear inclusions in both neurons and astrocytes. At the molecular level, FXTAS is characterized by increased expression of FMR1 sense and antisense RNA containing expanded CGG or GGC repeats, respectively. Here, we discuss the putative molecular mechanisms underlying FXTAS and notably recent reports that expanded CGG and GGC repeats may be pathogenic through RAN translation into toxic proteins.

Associations among oxytocin receptor gene (OXTR) DNA methylation in adulthood, exposure to early life adversity, and childhood trajectories of anxiousness

Recent models propose deoxyribonucleic acid methylation of key neuro-regulatory genes as a molecular mechanism underlying the increased risk of mental disorder associated with early life adversity (ELA). The goal of this study was to examine the association of ELA with oxytocin receptor gene (OXTR) methylation among young adults. Drawing from a 21-year longitudinal cohort, we compared adulthood OXTR methylation frequency of 46 adults (23 males and 23 females) selected for high or low ELA exposure based on childhood socioeconomic status and exposure to physical and sexual abuse during childhood and adolescence. Associations between OXTR methylation and teacher-rated childhood trajectories of anxiousness were also assessed. ELA exposure was associated with one significant CpG site in the first intron among females, but not among males. Similarly, childhood trajectories of anxiousness were related to one significant CpG site within the promoter region among females, but not among males. This study suggests that females might be more sensitive to the impact of ELA on OXTR methylation than males.

Parenting begets parenting: A neurobiological perspective on early adversity and the transmission of parenting styles across generations

The developing brains of young children are highly sensitive to input from their social environment. Nurturing social experience during this time promotes the acquisition of social and cognitive skills and emotional competencies. However, many young children are confronted with obstacles to healthy development, including poverty, inappropriate care, and violence, and their enhanced sensitivity to the social environment means that they are highly susceptible to these adverse childhood experiences. One source of social adversity in early life can stem from parenting that is harsh, inconsistent, non-sensitive or hostile. Parenting is considered to be the cornerstone of early socio-emotional development and an adverse parenting style is associated with adjustment problems and a higher risk of developing mood and behavioral disorders. Importantly, there is a growing literature showing that an important predictor of parenting behavior is how parents, especially mothers, were parented themselves. In this review, we examine how adversity in early-life affects mothering behavior in later-life and how these effects may be perpetuated inter-generationally. Relying on studies in humans and animal models, we consider evidence for the intergenerational transmission of mothering styles. We then describe the psychological underpinnings of mothering, including responsiveness to young, executive function and affect, as well as the physiological mediators of mothering behavior, including hormones, brain regions and neurotransmitters, and we consider how development in these relevant domains may be affected by adversity experienced in early life. Finally, we explore how genes and early experience interact to predict mothering behavior, including the involvement of epigenetic mechanisms. Understanding how adverse parenting begets adverse parenting in the next generation is critical for designing interventions aimed at preventing this intergenerational cycle of early adversity.

Environmental influence of problematic social relationships on adolescents' daily cortisol secretion: a monozygotic twin-difference study

BACKGROUND

This study investigated the potential environmental effects of peer victimization and the quality of relationships with parents and friends on diurnal cortisol secretion in mid-adolescence.

METHOD

This study used the monozygotic (MZ) twin-difference design to control for genetic effects and thus estimate the unique environmental influences on diurnal cortisol. Participants were 136 MZ twin pairs (74 female pairs) for whom cortisol was assessed four times per day over four collection days grouped in a 2-week period in grade 8 (mean age = 14.07 years). Participants also provided self-reports of peer victimization from grade 4 to grade 8 and of the relationship quality with the mother, father and best friend in grade 8.

RESULTS

The expected pattern of diurnal cortisol secretion was observed, with high levels at awakening followed by an increase 30 min later and a progressive decrease subsequently. Controlling for a host of confounders, only within-twin pair differences in peer victimization and a problematic relationship with the mother were significantly linked to twin differences in diurnal cortisol secretion. Specifically, whereas a more problematic mother-child relationship was associated with morning cortisol secretion, peer victimization was linked to cortisol secretion later in the day (diurnal slope).

CONCLUSIONS

Controlling for genetic influences and other confounders, stressful relationships with peers and the mother exert unique and time-specific environmental influences on the pattern of diurnal cortisol secretion in mid-adolescence.

Severe congenital malformations, family functioning and parents' separation/divorce: a longitudinal study

BACKGROUND

We aim to explore the association of a severe congenital malformation (SCM) with postnatal family functioning and parents' separation/divorce and to examine if this association might be moderated by birth order of the child and parental level of education. SCM refers to malformations that, without medical intervention, cause handicap or death.

METHODS

Using the Quebec Longitudinal Study of Child Development, an ongoing population-based birth cohort study initiated in 1998, we compared 1675 families of children with and without a SCM to identify if having a child with a SCM was associated with maternal perception of family functioning. We examined if an SCM was associated with parents' separation and examined parents' education level and birth order of the children to evaluate whether these factors had any moderating effect on the results.

RESULTS

There were no significant differences in family functioning between families with and without a SCM child at 5 and 17 months. At 5 months, family functioning was significantly better (P = 0.03) for families with a SCM firstborn child than for families with a SCM child that is not firstborn. For parental separation, no significant differences were observed at 5 and 29 months and 4 years. No significant moderating effects were observed for birth order and parental education on parental separation.

CONCLUSIONS

Families of children with a SCM do not appear to be at higher risk of family dysfunction within the first 17 months after birth nor of parental separation within the first 4 years after birth. Family functioning tends to be worst in families where the child with SCM is the second or subsequent child born.

Genetic and environmental aetiology of the dimensions of Callous-Unemotional traits

BACKGROUND

A Callous-Unemotional trait specifier (termed 'Limited Prosocial Emotions') was added to the diagnosis of conduct disorder in DSM-5. The Inventory of Callous-Unemotional Traits (ICU) is a comprehensive measure of these traits assessing three distinct, yet correlated dimensions--Callousness, Uncaring, and Unemotional--all thought to reflect the general Callous-Unemotional construct. The present study was the first to examine the degree to which the aetiology of these dimensions is shared v. independent.

METHOD

Parent-reported ICU data from 5092 16-year-old twin pairs from the Twins Early Development Study were subjected to confirmatory factor analysis. Multivariate genetic modelling was applied to the best-fitting structure.

RESULTS

A general-specific structure, retaining a general factor and two uncorrelated specific factors (Callousness-Uncaring, Unemotional), provided the best fit to the data. The general factor was substantially heritable (h2 = 0.58, 95% CI 0.51-0.65). Unusually, shared environmental influences were also important in accounting for this general factor (c2 = 0.26, 95% CI 0.22-0.31), in addition to non-shared environmental influences. The Unemotional dimension appeared phenotypically and genetically distinct as shown by the substantial loadings of unemotional items on a separate dimension and a low genetic correlation between Unemotional and Callousness-Uncaring.

CONCLUSIONS

A general factor, indicative of a shared phenotypic structure across the dimensions of the ICU was under substantial common genetic and more modest shared environment influences. Our findings also suggest that the relevance of the Unemotional dimension as part of a comprehensive assessment of CU traits should be investigated further.

Parenting begets parenting: A neurobiological perspective on early adversity and the transmission of parenting styles across generations

The developing brains of young children are highly sensitive to input from their social environment. Nurturing social experience during this time promotes the acquisition of social and cognitive skills and emotional competencies. However, many young children are confronted with obstacles to healthy development, including poverty, inappropriate care, and violence, and their enhanced sensitivity to the social environment means that they are highly susceptible to these adverse childhood experiences. One source of social adversity in early life can stem from parenting that is harsh, inconsistent, non-sensitive or hostile. Parenting is considered to be the cornerstone of early socio-emotional development and an adverse parenting style is associated with adjustment problems and a higher risk of developing mood and behavioral disorders. Importantly, there is a growing literature showing that an important predictor of parenting behavior is how parents, especially mothers, were parented themselves. In this review, we examine how adversity in early-life affects mothering behavior in later-life and how these effects may be perpetuated inter-generationally. Relying on studies in humans and animal models, we consider evidence for the intergenerational transmission of mothering styles. We then describe the psychological underpinnings of mothering, including responsiveness to young, executive function and affect, as well as the physiological mediators of mothering behavior, including hormones, brain regions and neurotransmitters, and we consider how development in these relevant domains may be affected by adversity experienced in early life. Finally, we explore how genes and early experience interact to predict mothering behavior, including the involvement of epigenetic mechanisms. Understanding how adverse parenting begets adverse parenting in the next generation is critical for designing interventions aimed at preventing this intergenerational cycle of early adversity.

Immunological correlates of behavioral problems in school-aged children living with HIV in Kayunga, Uganda

BACKGROUND

HIV can affect the neuropsychological function of children, including their behavior. We aim to identify immunological correlates of behavioral problems among children living with HIV in Uganda.

METHODS

Children participating in a parent randomized control trial in Kayunga, Uganda were assessed with the Behavior Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL). We constructed simple and multiple linear regression models to identify immunological correlates of behavioral problems.

RESULTS

A total of 144 children living with HIV (50% male) with a mean age of 8.9 years [Standard Deviation (s.d.) = 1.9] were included in the analysis. Eighty-two children were on antiretroviral therapy. Mean CD4 cell count % was 35.1 cells/μl (s.d. = 15.0), mean CD4 cell activation 5.7% (s.d. = 5.1), mean CD8 cell activation was 17.5% (s.d. = 11.2) and 60 children (41.7%) had a viral load of <4000 copies/ml. In the adjusted models for the BRIEF, higher scores were associated with higher viral loads (aβ = 16.7 × 10-6, 95% CI -5.00 × 10-6 to 28.4 × 10-6), specifically on the behavioral regulation index. Higher mean CD8 activation % was associated with higher scores on the Externalizing Problems  and Total Problems  scales of the CBCL (aβ = 0.17, 95% CI 0.04-0.31 and aβ = 0.15, 95% CI 0.00-0.28, respectively).

CONCLUSIONS

Poorer behavioral outcomes were associated with higher viral loads while higher CD8 activation was associated with poorer emotional and behavioral outcomes. Complete immunological assessments for children living with HIV could include commonly used viral and immunological parameters to identify those at higher risk of having negative behavior outcomes and who would benefit the most from behavioral interventions.

Executive function and attention-deficit/hyperactivity disorder in Ugandan children with perinatal HIV exposure

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is among the most commonly diagnosed mental disorders in childhood and is associated with substantial deficits in executive functioning and lost academic and occupational attainment. This study evaluates symptoms of ADHD and their association with neurocognitive deficits in a cohort of rural Ugandan children who were born to HIV-infected mothers.

METHODS

We assessed ADHD symptoms and executive function (including memory and attention) in a non-clinical sample of children born to HIV-infected mothers in rural eastern Uganda. Analyses included assessments of the psychometric properties, factor structure, and convergent and discriminant validity of the ADHD measure (ADHD-Rating Scale-IV); and executive function deficits in children meeting symptom criteria for ADHD.

RESULTS

232 children [54% female; mean age 7.8 years (s.d. 2.0)] were assessed for ADHD and executive function deficits. The ADHD measure showed good internal consistency (α = 0.85.) Confirmatory factor analysis showed an acceptable fit for the diagnostic and statistical manual of mental disorders (DSM-5) two-factor model. Subjects meeting DSM-5 symptom criteria for ADHD had worse parent-rated executive function on six out of seven subscales.

CONCLUSIONS

Our results demonstrate structural validity of the ADHD measure with this population, strong associations between ADHD symptom severity and poorer executive function, and higher levels of executive function problems in perinatally HIV-exposed Ugandan children with ADHD. These findings suggest that ADHD may be an important neurocognitive disorder associated with executive function problems among children in sub-Saharan African settings where perinatal HIV exposure is common.

A longitudinal twin study of physical aggression during early childhood: evidence for a developmentally dynamic genome

BACKGROUND

Physical aggression (PA) tends to have its onset in infancy and to increase rapidly in frequency. Very little is known about the genetic and environmental etiology of PA development during early childhood. We investigated the temporal pattern of genetic and environmental etiology of PA during this crucial developmental period.

METHOD

Participants were 667 twin pairs, including 254 monozygotic and 413 dizygotic pairs, from the ongoing longitudinal Quebec Newborn Twin Study. Maternal reports of PA were obtained from three waves of data at 20, 32 and 50 months. These reports were analysed using a biometric Cholesky decomposition and linear latent growth curve model.

RESULTS

The best-fitting Cholesky model revealed developmentally dynamic effects, mostly genetic attenuation and innovation. The contribution of genetic factors at 20 months substantially decreased over time, while new genetic effects appeared later on. The linear latent growth curve model revealed a significant moderate increase in PA from 20 to 50 months. Two separate sets of uncorrelated genetic factors accounted for the variation in initial level and growth rate. Non-shared and shared environments had no effect on the stability, initial status and growth rate in PA.

CONCLUSIONS

Genetic factors underlie PA frequency and stability during early childhood; they are also responsible for initial status and growth rate in PA. The contribution of shared environment is modest, and perhaps limited, as it appears only at 50 months. Future research should investigate the complex nature of these dynamic genetic factors through genetic-environment correlation (r GE) and interaction (G×E) analyses.

Family Characteristics and Children's Preschool Trajectories of Disruptive Behaviours

Aim:

The aim of this study was to investigate the association between parental characteristics and parental practices and the trajectories of Disruptive Behaviours (DBs) during early childhood.

Method:

Trajectories of DBs - Hyperactivity, Oppositional behaviour and Physical Aggression - were assessed based on annual mother interviews from 17 to 60 months for a Canadian population-representative birth cohort (N=2057).

Results:

Frequency of DBs increased from 17 to 41 months and then tended to decline. Parental characteristics and parental practices were both associated with chronic trajectories of DBs.

Conclusion:

Early childhood is a critical period to prevent later DBs during school years that leads to psychosocial maladjustment during adolescence and adulthood.

Intolerance to visceral distension in functional dyspepsia or irritable bowel syndrome: an organ specific defect or a pan intestinal dysregulation?

Functional gastrointestinal disorders (FGID) are characterized by visceral hypersensitivity that could be specific to a region of the gut or reflect a diffuse pan-intestinal disorder. Sensory thresholds to distension at two visceral sites in patients with different FGIDs were determined. According to Rome II criteria, 30 patients from three groups were studied: patients with (i) functional dyspepsia (FD) or (ii) irritable bowel syndrome (IBS), and (iii) patients with concomitant symptoms of FD and IBS. Pain thresholds to balloon distension were determined in stomach and rectum. In FD patients, gastric intolerance to balloon distension was found in 91% patients; rectal hypersensitivity was documented in 18% patients. In IBS patients, rectal hypersensitivity was seen in 75% patients; while gastric hypersensitivity was never found. In patients with concomitant symptoms of FD + IBS, gastric and rectal intolerance to distension were present respectively in 82 and 91% patients. In the whole group, visceral intolerance to distension was documented at one site in 90% patients and at both sites, i.e. stomach and rectum, in 33% patients. Visceral intolerance to distension can be pan-intestinal in patients with multiple sites of symptoms, but appears organ-specific in patients exhibiting a specific site of symptoms.

Socioeconomic impact of irritable bowel syndrome in Canada

Irritable bowel syndrome (IBS) is the most common functional gastroenterological disorder reported to physicians. In Canada, its prevalence is about 6%. In the United States and the United Kingdom, the prevalence is estimated to be closer to 15%. Patients with IBS tend to make extensive use of health care services, even though a high percentage of them do not seek medical advice. The costs of IBS are a large expenditure of scarce resources. These costs can be divided into several categories: direct, indirect and intangible costs. The direct costs, associated with the diagnosis and treatment, are largely sustained by the health care system. The indirect costs are related to the production losses due to morbidity, and intangible costs are associated with the pain, suffering and alteration in the patient's quality of life. The condition is a diagnosis of exclusion, and treatment, although beneficial, is rarely curative. The general treatment approach stresses the importance of a good physician-patient relationship. Exploring the nature of the expenses associated with IBS and understanding how treatment options may affect these costs are essential to reducing its financial burden.

Mechanical properties of coronary stents determined by using finite element analysis

The mechanical function of a stent deployed in a damaged artery is to provide a metallic tubular mesh structure. The purpose of this study was to determine the exact mechanical characteristics of stents. In order to achieve this, we have used finite-element analysis to model two different type of stents: tubular stents (TS) and coil stents (CS). The two stents chosen for this modeling present the most extreme mechanical characteristics of the respective types. Seven mechanical properties were studied by mathematical modeling with determination of: (1) stent deployment pressure, (2) the intrinsic elastic recoil of the material used, (3) the resistance of the stent to external compressive forces, (4) the stent foreshortening, (5) the stent coverage area, (6) the stent flexibility, and (7) the stress maps. The pressure required for deployment of CS was significantly lower than that required for TS, over 2.8 times greater pressure was required for the tubular model. The elastic recoil of TS is higher than CS (5.4% and 2.6%, respectively). TS could be deformed by 10% at compressive pressures of between 0.7 and 1.3 atm whereas CS was only deformed at 0.2 and 0.7 atm. The degree of shortening observed increases with deployment diameter for TS. CS lengthen during deployment. The metal coverage area is two times greater for TS than for CS. The ratio between the stiffness of TS and that of CS varies from 2060 to 2858 depending on the direction in which the force is applied. TS are very rigid and CS are significantly more flexible. Stress mapping shows stress to be localized at link nodes. This series of finite-element analyses illustrates and quantifies the main mechanical characteristics of two different commonly used stents. In interventional cardiology, we need to understand their mechanisms of implantation and action.

Normal parathyroid function with decreased bone mineral density in treated celiac disease

Decreased bone mineral density (BMD) has been reported in patients with celiac disease in association with secondary hyperparathyroidism. The present study investigated whether basal parathyroid hormone (PTH) remained elevated and whether abnormalities of parathyroid function were still present in celiac disease patients treated with a gluten-free diet. Basal seric measurements of calcium and phosphate homeostasis and BMD were obtained in 17 biopsy-proven patients under treatment for a mean period of 5.7+/-3.7 years (range 1.1 to 15.9). In addition, parathyroid function was studied with calcium chloride and sodium citrate infusions in seven patients. Basal measurements of patients were compared with those of 26 normal individuals, while parathyroid function results were compared with those of seven sex- and age-matched controls. Basal results were similar in patients and controls except for intact PTH (I-PTH) (3.77+/-0.88 pmol/L versus 2.28+/-0.63 pmol/L, P<0.001), which was higher in the former group but still within normal limits. Mean 25-hydroxy vitamin D and 1,25-dihydroxy vitamin D values were normal in patients. Parathyroid function results were also found to be similar in both groups. Compared with a reference population of the same age (Z score), patients had significantly lower BMDs of the hip (-0.60+/-0.96 SDs, P<0.05) and lumbar spine (-0.76+/-1.15 SDs, P<0.05). T scores were also decreased for the hip (-1.3+/-0.9 SDs, P<0.0001) and lumbar spine (-1.4+/-1.35 SDs, P<0.0001), with two to three patients being osteoporotic (T score less than -2.5 SDs) and seven to eight osteopenic (T score less than -1 SDs but greater than or equal to -2.5 SDs) in at least one site. Height and weight were the only important determinants of BMD values by multivariate or logistical regression analysis in these patients. The results show higher basal I-PTH values with normal parathyroid function in treated celiac disease. Height and weight values are, but I-PTH values are not, an important determinant of the actual bone mass of patients. Normal parathyroid function in treated patients suggests a lack of previous severe secondary hyperparathyroidism and/or complete adaptation to prior changes in parathyroid function.

Mediators of behavioral problems in 7-year-old children born after 24 to 28 weeks of gestation

We tested the hypothesis that prematurity acts through its association with neuromotor and intellectual functioning to explain behavior problems at school age. Sixty-one extremely preterm (EP) very low birth weight (VLBW) children (< 29 wk and < 1,500 g) born in 1987-1990 and 44 normal birth weight children (NBW) (> 37 wk and > 2,500 g) were matched for age, sex, and socioeconomic status (SES). Mediator variables were evaluated at a hospital at 5 years and 9 months. Behaviors were evaluated at school at 7 years by peers, teachers, and parents. When compared with NBW children, EP/VLBW children had poorer IQ and neuromotor development. At school, EP/VLBW children were evaluated by peers as more sensitive/ isolated, and by teachers and parents as more inattentive and hyperactive than NBW. When mediators were introduced, the previously significant relation between prematurity and behavior problems disappeared. Hyperactive and inattentive behaviors were explained by a specific working memory factor for the latter, and by a general intellectual delay for the former, whereas sensitive/isolated behaviors were best explained by neuromotor delays. Inattentive behaviors were also related to family adversity. At school age, extreme prematurity had thus an indirect effect on behaviors via specific and nonspecific intellectual and neuromotor delays.

A multicenter, prospective study of the placement of transpyloric feeding tubes with assistance of a magnetic device. The Magnet-Guided Enteral Feeding Tube Study Group

BACKGROUND

Placement of feeding tubes in the transpyloric position can be helpful in the management of enterally fed patients with pancreatitis, gastric atony, enterocutaneous fistulae, or pulmonary aspiration risk. The attainment of transpyloric position is difficult, and numerous techniques have been proposed to help in achieving this location. Recently, the use of a magnet-tipped feeding tube, dragged into proper position with an external magnet, has been described with an excellent success rate.

METHODS

At 10 participating institutions, practitioners were trained in the use of the device. Successful tube placement was determined by abdominal radiograph.

RESULTS

One hundred fifty-six tube placements were attempted. Transpyloric position was obtained in 60%. Placement into the third portion of the duodenum or distal was obtained in only 32%. Analysis of the data did not reveal a learning curve at the institutions, and 7 of 10 had a 50% or lower success rate.

CONCLUSIONS

Placement of feeding tubes with the assistance of a magnetic device was infrequently successful at the majority of institutions where it was attempted. We report a lower success rate than the original article, which described an 88% success rate of transpyloric intubation. Although this technique has a high failure rate, some individuals seem to be very successful using it, which could reduce the need for endoscopy or transport for the placement of feeding tubes.

Reactive and proactive aggression: evidence of a two-factor model

This article examines the construct validity of reactive and proactive aggression, as assessed by the teacher-rating scale developed by K. A. Dodge and J. D. Coie (1987). In Study 1 (n = 149 boys), confirmatory factor analyses revealed that a 2-factor model, in which a substantial correlation was observed between the 2 latent factors, presented a better fit than a single-factor model. Study 2 (n = 193 boys) examined the relations presented by the 2 forms of aggression with peer status, leadership, social withdrawal, and victimization by peer. Reactive and proactive aggressive behaviors presented distinct patterns of relations consistent with the theoretical definitions. The results of these studies suggest that the questionnaire measures 2 forms of aggressive behavior that, although being substantially related, have a unique discriminant dimension.

Assessment of gastric emptying using a low fat meal: establishment of international control values

OBJECTIVE

The diagnosis of gastroparesis implies delayed gastric emptying. The diagnostic gold standard is scintigraphy, but techniques and measured endpoints vary widely among institutions. In this study, a simplified scintigraphic measurement of gastric emptying was compared to conventional gastric scintigraphic techniques and normal gastric emptying values defined in healthy subjects.

METHODS

In 123 volunteers (aged 19-73 yr, 60 women and 63 men) from 11 centers, scintigraphy was used to assess gastric emptying of a 99Tc-labeled low fat meal (egg substitute) and percent intragastric residual contents 60, 120, and 240 min after completion of the meal. In 42 subjects, additional measurements were taken every 10 min for 1 h. In 20 subjects, gastric emptying of a 99Tc-labeled liver meal was compared with that of the 99Tc-labeled low fat meal.

RESULTS

Median values (95th percentile) for percent gastric retention at 60, 120, and 240 min were 69% (90%), 24% (60%) and 1.2% (10%) respectively. A power exponential model yielded similar emptying curves and estimated T50 when using images only taken at 1, 2 and 4 h, or with imaging taken every 10 min. Gastric emptying was initially more rapid in men but was comparable in men and women at 4 h; it was faster in older subjects (p < 0.05) but was independent of body mass index.

CONCLUSIONS

This multicenter study provides gastric emptying values in healthy subjects based on data obtained using a large sample size and consistent meal and methodology. Gastric retention of >10% at 4 h is indicative of delayed emptying, a value comparable to those provided by more intensive scanning approaches. Gastric emptying of a low fat meal is initially faster in men but is comparable in women at 4 h; it is also faster in older individuals but is independent of body mass.

Reactive and proactive aggression: evidence of a two-factor model

This article examines the construct validity of reactive and proactive aggression, as assessed by the teacher-rating scale developed by K. A. Dodge and J. D. Coie (1987). In Study 1 (n = 149 boys), confirmatory factor analyses revealed that a 2-factor model, in which a substantial correlation was observed between the 2 latent factors, presented a better fit than a single-factor model. Study 2 (n = 193 boys) examined the relations presented by the 2 forms of aggression with peer status, leadership, social withdrawal, and victimization by peer. Reactive and proactive aggressive behaviors presented distinct patterns of relations consistent with the theoretical definitions. The results of these studies suggest that the questionnaire measures 2 forms of aggressive behavior that, although being substantially related, have a unique discriminant dimension.

Uncoupling protein-2 and -3 messenger ribonucleic acids in adipose tissue and skeletal muscle of healthy males: variability, factors affecting expression, and relation to measures of metabolic rate

Mitochondrial uncoupling protein-2 and -3 (UCP2 and UCP3) may be involved in the modulation of resting metabolic rate and energy balance. To investigate their variability, the influence of this on the variability of energy expenditure, and potential regulatory factors of the expression of the corresponding genes, we measured their messenger ribonucleic acids (mRNAs) in muscle and white adipose tissue of lean, healthy men and correlated the abundance of these mRNAs (attomoles per microg total RNA) with measures of resting metabolic rate, hormone levels (thyroid hormones, insulin, glucagon, leptin, and catecholamines), and fuels potentially involved in energy balance regulation. We also investigated whether the thiazolidinedione, troglitazone, stimulates UCP2 and UCP3 mRNA levels to follow up on the observation that this antidiabetic drug increases the levels of expression in cultured cells. We found UCP2 and UCP3 mRNA levels to be highly variable and poorly correlated with measures of energy expenditure and with most factors affecting energy balance. Only nocturnal urinary norepinephrine excretion could explain a significant fraction of the variability in both UCP2 and UCP3 expression in muscle, but not adipose tissue. Thyroid hormone and norepinephrine excretion were found to contribute to the variability of resting metabolic rate, but this could not be explained by an effect on UCP mRNAs. Troglitazone affected neither the expression of UCPs nor the hormones or the measures of metabolic rate investigated. In conclusion, our results show that the expression of UCP2 and UCP3 genes is quite variable in healthy males and that this variability does not explain that in resting energy expenditure, and suggest that sympathetic activity is an important potential regulator of the expression of these proteins in skeletal muscle. However, the data do not support the concept that regulation of the expression of these genes is the most important level of control of UCP3 and UCP2 functions, and other levels of control have to be invoked.

The role of proactive and reactive aggression in the formation and development of boys' friendships

This study tested the hypothesis that friends are more similar in proactive aggression than in reactive aggression. Interpersonal processes that may account for this similarity (i.e., selection and mutual influence) were also examined. In the fall and spring of the school year, the friendships of 185 4th-, 5th-, and 6th-grade boys were identified. Proactive and reactive aggressive behavior were assessed with a teacher-rating instrument for each boy. The results support the general hypothesis and suggest that proactively aggressive boys tend to select proactively aggressive peers as friends; however, mutual influence between stable friends does not appear to account for similarity. These findings are discussed within the framework of G. R. Patterson, J. B. Reid, and T. J. Dishion's (1992) theory of antisocial behavior.

The role of proactive and reactive aggression in the formation and development of boys' friendships

This study tested the hypothesis that friends are more similar in proactive aggression than in reactive aggression. Interpersonal processes that may account for this similarity (i.e., selection and mutual influence) were also examined. In the fall and spring of the school year, the friendships of 185 4th-, 5th-, and 6th-grade boys were identified. Proactive and reactive aggressive behavior were assessed with a teacher-rating instrument for each boy. The results support the general hypothesis and suggest that proactively aggressive boys tend to select proactively aggressive peers as friends; however, mutual influence between stable friends does not appear to account for similarity. These findings are discussed within the framework of G. R. Patterson, J. B. Reid, and T. J. Dishion's (1992) theory of antisocial behavior.

Standardization of a simplified scintigraphic methodology for the assessment of gastric emptying in a multicenter setting

OBJECTIVE

Scintigraphy remains the gold standard to study gastric emptying. The technique is onerous and normal values vary between centers. Standardized protocols, although desirable, are not presently available. We validated a simplified scintigraphic protocol in a multicenter setting.

METHODS

In 69 healthy volunteers from seven Canadian institutions, gastric emptying of a standard meal (99mTc-labeled beef liver) was assessed by scintigraphy every 10 min for 1 h, then every 20 min for the next 2 h. Gastric retention was fitted to a power exponential model, Prop(t) = (-(kappat)beta) with Prop(t) = proportion of retention at time t, either using all 13 time intervals (conventional technique) or using measurements at 0, 1, 2, and 3 h (simplified technique).

RESULTS

The power exponential model yielded identical emptying curves and T 1/2 values with both techniques. Gastric emptying was more rapid in men than in women < 35 yr (p<0.01) and in younger than in older men (p<0.005). Gastric emptying was slower in women from Québec than in women from Ontario (p<0.04). Gastric retention was similar at 1, 2, and 3 h among the seven centers. Gastric emptying of a beef liver meal was slower than that of a low fat egg substitute (p<0.03).

CONCLUSIONS

A simpler scintigraphic approach, using four rather than 13 samples, provides results comparable to those of the conventional technique. This simpler approach provides an economical, yet accurate, alternative to the techniques presently used and is applicable to a multicenter setting.

[Categorical refusal of treatment by psychiatric patients: balance, survey and prospects]

BACKGROUND

In his or her practice, a psychiatrist must often deal with patients who refuse treatment. In 1990, Quebec radically changed this situation by introducing a Civil Code provision imposing judicial intervention to treat an individual deemed unfit to consent, against his or her will. This paper presents an assessment and survey of patients and attending psychiatrists who have used this Code provision.

METHOD

Thirty-nine subjects who explicitly refused treatment were brought to court. We asked a subgroup of these patients to be interviewed, using the Drug Attitude Inventory (DAI), the Clinical Global Impression (CGI), and 2 questionnaires specifically considering the court experience of patients and attending psychiatrists.

RESULTS

The results of the survey show that patients remember their experience in court as rather uncomfortable. However, the therapeutic alliance remained unchanged, even after the legal procedure. Physicians agreed that patients would not have been clinically well enough to leave the hospital if they had not received the drug regimen resulting from the court decision. The dissociation between the perceptions of patients and physicians is compared with that found in previous studies in the United States.

CONCLUSION

Even with a limited sample, this study addresses a delicate, difficult situation that professionals are increasingly likely to confront. It also proposes further research on alternatives to judicial intervention.

The power of friendship: protection against an escalating cycle of peer victimization

This study examined 2 aspects of friendship (presence and perceived qualities of a best friend) as moderators of behavioral antecedents and outcomes of peer victimization. A total of 393 children (188 boys and 205 girls) in the 4th and 5th grades (mean age = 10 years 7 months) participated during each of 2 waves of data collection in this 1-year longitudinal study. Results indicated that teacher-reported internalizing and externalizing behaviors predicted increases in peer-reported victimization, but the relation of internalizing behaviors to increases in victimization was attenuated for children with a protective friendship. Victimization predicted increases in internalizing and externalizing behaviors but only for children without a mutual best friendship. Results highlight the importance of peer friendships in preventing an escalating cycle of peer abuse.

The power of friendship: protection against an escalating cycle of peer victimization

This study examined 2 aspects of friendship (presence and perceived qualities of a best friend) as moderators of behavioral antecedents and outcomes of peer victimization. A total of 393 children (188 boys and 205 girls) in the 4th and 5th grades (mean age = 10 years 7 months) participated during each of 2 waves of data collection in this 1-year longitudinal study. Results indicated that teacher-reported internalizing and externalizing behaviors predicted increases in peer-reported victimization, but the relation of internalizing behaviors to increases in victimization was attenuated for children with a protective friendship. Victimization predicted increases in internalizing and externalizing behaviors but only for children without a mutual best friendship. Results highlight the importance of peer friendships in preventing an escalating cycle of peer abuse.

Evaluation of gastric emptying function in clinical practice

In this retrospective analysis, we compared different methods to evaluate gastric emptying function, aiming to improve the sensitivity and the clinical availability of our diagnostic testing. In the first study, we compared, in 72 patients clinically suspected of gastroparesis, the emptying of a meal containing two solid nutrients with different disintegration rates: 111In-labeled scrambled eggs and 99Tc-labeled liver cubes. Gastric emptying of 111In-labeled egg was delayed in 12 of our patients and the evacuation of the 99Tc-labeled liver was prolonged in 19 patients. The choice of the nutrient was not important for the identification of diabetic gastroparesis (43% vs 57%; NS), but it was determinant in the case of patients suspected of idiopathic gastroparesis (12% were positive with the egg and 25% with the liver; P < 0.05). In the second study, we compared two different diagnostic methods in 46 patients: a simple radiological detection of the gastric emptying of radiopaque pellets, and the scintigraphic emptying of a solid meal containing 99Tc-labeled liver cubes. Both tests correlated perfectly in 78% of our patients. In 15% of the population (six of these seven patients were diabetics suspected of gastroparesis) the scintigraphic method was normal, while the evacuation of radiopaque pellets was delayed. For clinical purposes, we therefore propose: (1) the scintigraphic method should use liver rather than egg as a radiolabeled tracer in order to improve the sensitivity of the test for detection of gastroparesis; and (2) the radiological detection of radiopaque markers is a reliable and convenient method for the detection of gastroparesis in clinical practice. It is possibly more sensitive than scintigraphy.

The Second Canadian Consensus Conference on the Management of Patients with Gastroesophageal Reflux Disease

The Second Canadian Consensus Conference on the Management of Patients with Gastroesophageal Reflux Disease (GERD) was organized by the Canadian Association of Gastroenterology to address major advances in the understanding of the pathophysiology of GERD, to review the new methods of investigation and therapy introduced since the first conference in 1992 and to examine the issue of relevant health economics. The changes that have taken place over the past four years have been sufficiently dramatic to necessitate reassessment of the recommendations made following the first conference. The second conference dealt with the investigation and treatment of uncomplicated GERD and the complex issues of esophageal and extraesophageal complications such as chest pain, Barrett's esophagus, and reflux-related pulmonary and laryngeal disorders. The role of laparoscopic surgery was also discussed. A decision tree for investigation and treatment of patients with GERD was developed. The 38 participants represented a broad spectrum of experience, location of practice and special interests. The distribution of participants conformed to the recommendations of the Canadian Medical Association guidelines for consensus documents in that there should be input from all possible interested parties. A list of the state-of-the-art lectures presented during the conference, the small group sessions, the session chairpersons and participants are appended to this document. CONCLUSIONS. UNCOMPLICATED GERD: GERD with alarm symptoms must be investigated immediately. There was no consensus about when to investigate uncomplicated GERD, ie, whether to perform endoscopy immediately or after initial therapy fails. There was controversy regarding 'step up' (H2 receptor antagonist [H2RA] or prokinetic [PK] first therapy) versus 'step down' therapy (proton pump inhibitor [PPI] first therapy). The majority decision was for short term 'step up' therapy and investigation if symptoms do not improve or recur. Maintenance therapy should be carried out with the initial therapy that was effective. H2RAs and PKs may suffice for maintenance therapy in milder GERD; however, for severe esophagitis, PPIs should be used.

SURGERY

Indications for laparoscopic surgery should be the same as for conventional antireflux operations. NONCARDIAC ANGINA-LIKE CHEST PAIN: After exclusion of nonesophageal causes, the majority decided that eight weeks of therapy with a PPI should be performed, while some suggested work-up before a therapeutic test. In the absence of response or recurrence, esophagogastroduodenoscopy (EGD) and, depending on the circumstances, 24 h ambulatory pH/motility may be indicated. BARRETT'S ESOPHAGUS: Only patients who, in case of future discovery of cancer or dysplasia, are able or willing to undergo therapy should have surveillance. In the absence of dysplasia EGD should be performed every two years, and in the presence of mild dysplasia every three to six months. All agreed that for severe dysplasia, esophagectomy or poor risk patients, esophageal mucosal ablation is indicated. ESTRAESOPHAGEAL COMPLICATONS (EECs): Asthma, chronic cough and posterior laryngitis were considered EECs. Although PPIs may decrease symptoms, improvement alone is not diagnostic of the presence of EEC. Ambulatory pH studies with two pH probes or ambulatory pH/motility may be useful in establishing causation.

HEALTH ECONOMICS

There are limited data for an economic comparison among the different drugs or between medical and surgical therapy.

Management of complicated gastroesophageal reflux disease: atypical chest pain

Although most patients with gastroesophageal reflux disease (GERD) present with the classic symptoms of heartburn and acid regurgitation, many complain of atypical chest pain suggestive of cardiac disease. Once cardiac ischemia has been excluded, it is important to consider GERD because this may be established as the cause of pain in 10% to 50% of such patients. If GERD is suspected or documented, vigorous antireflux treatment, preferably with proton pump inhibitory therapy, is indicated.

Vaccination against Eimeria magna coccidiosis using spray dispersion of precocious line oocysts in the nest box

Coccidiosis mostly affects young rabbits just after weaning (5- to 6-week-old animals). Prevention of this disease must therefore be initiated before weaning. 'Precocious lines', derived from field species display good immunogenicity, though not pathogenic when administered at the right dose. In the present work, we tested the vaccination method of the whole litter at 25 days of age by spray dispersion of oocysts of a precocious line of Eimeria magna in the nest box. Three doses were tested, d1 = 4 x 10(2) oocysts, d2 = 4 x 10(3) oocysts, d3 = 4 x 10(4) oocysts. The animals were challenged individually with 10(4) oocysts of a wild strain of E. magna at 35 days of age, 5 days after weaning. The oocyst output and weight gain were recorded after vaccination and after challenge. The vaccinated animals did not display any vaccine reaction. The dose d3 was totally effective on oocyst output and on weight gain under our experimental conditions. As our challenge conditions were severe, we think that a lower vaccine dose could be used. This method proved to be efficient, and quick and easy to use because it did not require animal manipulation.