Adapting a measure of gross motor skills for individuals with CDKL5 deficiency disorder: A psychometric study.

PURPOSE: Validated measures capable of demonstrating meaningful interventional change in the CDKL5 deficiency disorder (CDD) are lacking. The study objective was to modify the Rett Syndrome Gross Motor Scale (RSGMS) and evaluate its psychometric properties for individuals with CDD. METHODS: Item and scoring categories of the RSGMS were modified. Caregivers registered with the International CDKL5 Clinical Research Network uploaded motor videos filmed at home to a protected server and completed a feedback questionnaire (n = 70). Rasch (n = 137), known groups (n = 109), and intra- and inter-rater reliability analyses (n = 50) were conducted. RESULTS: The age of individuals with CDD ranged from 1.5 to 34.1 years. The modified scale, Gross Motor-Complex Disability (GM-CD), comprised 17 items. There were no floor or ceiling effects and inter- and intra-rater reliability were good. Rasch analysis demonstrated that the items encompassed a large range of performance difficulty, although there was some item redundancy and some disordered categories. One item, Prone Head Position, was a poor fit. Caregiver-reported acceptability was positive. Scores differed by age and functional abilities. SUMMARY: GM-CD appears to be a suitable remotely administered measure and psychometrically sound for individuals with CDD. This study provides the foundation to propose the use of GM-CD in CDD clinical trials. Longitudinal evaluation is planned.

Prenatal iodine supplementation and early childhood neurodevelopment: the PoppiE trial - study protocol for a multicentre randomised controlled trial.

INTRODUCTION: Observational studies suggest both low and high iodine intakes in pregnancy are associated with poorer neurodevelopmental outcomes in children. This raises concern that current universal iodine supplement recommendations for pregnant women in populations considered to be iodine sufficient may negatively impact child neurodevelopment. We aim to determine the effect of reducing iodine intake from supplements for women who have adequate iodine intake from food on the cognitive development of children at 24 months of age. METHODS AND ANALYSIS: A multicentre, randomised, controlled, clinician, researcher and participant blinded trial with two parallel groups. Using a hybrid decentralised clinical trial model, 754 women (377 per group) less than 13 weeks' gestation with an iodine intake of ≥165 µg/day from food will be randomised to receive either a low iodine (20 µg/day) multivitamin and mineral supplement or an identical supplement containing 200) µg/day (amount commonly used in prenatal supplements in Australia), from enrolment until delivery. The primary outcome is the developmental quotient of infants at 24 months of age assessed with the Cognitive Scale of the Bayley Scales of Infant Development, fourth edition. Secondary outcomes include infant language and motor development; behavioural and emotional development; maternal and infant clinical outcomes and health service utilisation of children. Cognitive scores will be compared between groups using linear regression, with adjustment for location of enrolment and the treatment effect described as a mean difference with 95% CI. ETHICS AND DISSEMINATION: Ethical approval has been granted from the Women's and Children's Health Network Research Ethics Committee (HREC/17/WCHN/187). The results of this trial will be presented at scientific conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04586348.

Rapid assessment of hand reaching using virtual reality and application in cerebellar stroke.

The acquisition of sensory information about the world is a dynamic and interactive experience, yet the majority of sensory research focuses on perception without action and is conducted with participants who are passive observers with very limited control over their environment. This approach allows for highly controlled, repeatable experiments and has led to major advances in our understanding of basic sensory processing. Typical human perceptual experiences, however, are far more complex than conventional action-perception experiments and often involve bi-directional interactions between perception and action. Innovations in virtual reality (VR) technology offer an approach to close this notable disconnect between perceptual experiences and experiments. VR experiments can be conducted with a high level of empirical control while also allowing for movement and agency as well as controlled naturalistic environments. New VR technology also permits tracking of fine hand movements, allowing for seamless empirical integration of perception and action. Here, we used VR to assess how multisensory information and cognitive demands affect hand movements while reaching for virtual targets. First, we manipulated the visibility of the reaching hand to uncouple vision and proprioception in a task measuring accuracy while reaching toward a virtual target (n = 20, healthy young adults). The results, which as expected revealed multisensory facilitation, provided a rapid and a highly sensitive measure of isolated proprioceptive accuracy. In the second experiment, we presented the virtual target only briefly and showed that VR can be used as an efficient and robust measurement of spatial memory (n = 18, healthy young adults). Finally, to assess the feasibility of using VR to study perception and action in populations with physical disabilities, we showed that the results from the visual-proprioceptive task generalize to two patients with recent cerebellar stroke. Overall, we show that VR coupled with hand-tracking offers an efficient and adaptable way to study human perception and action.

Using Advanced Cell Culture Techniques to Differentiate Pluripotent Stem Cells and Recreate Tissue Structures Representative of Teratoma Xenografts.

Various methods are currently used to investigate human tissue differentiation, including human embryo culture and studies utilising pluripotent stem cells (PSCs) such as in vitro embryoid body formation and in vivo teratoma assays. Each method has its own distinct advantages, yet many are limited due to being unable to achieve the complexity and maturity of tissue structures observed in the developed human. The teratoma xenograft assay allows maturation of more complex tissue derivatives, but this method has ethical issues surrounding animal usage and significant protocol variation. In this study, we have combined three-dimensional (3D) in vitro cell technologies including the common technique of embryoid body (EB) formation with a novel porous scaffold membrane, in order to prolong cell viability and extend the differentiation of PSC derived EBs. This approach enables the formation of more complex morphologically identifiable 3D tissue structures representative of all three primary germ layers. Preliminary in vitro work with the human embryonal carcinoma line TERA2.SP12 demonstrated improved EB viability and enhanced tissue structure formation, comparable to teratocarcinoma xenografts derived in vivo from the same cell line. This is thought to be due to reduced diffusion distances as the shape of the spherical EB transforms and flattens, allowing for improved nutritional/oxygen support to the developing structures over extended periods. Further work with EBs derived from murine embryonic stem cells demonstrated that the formation of a wide range of complex, recognisable tissue structures could be achieved within 2-3 weeks of culture. Rudimentary tissue structures from all three germ layers were present, including epidermal, cartilage and epithelial tissues, again, strongly resembling tissue structure of teratoma xenografts of the same cell line. Proof of concept work with EBs derived from the human embryonic stem cell line H9 also showed the ability to form complex tissue structures within this system. This novel yet simple model offers a controllable, reproducible method to achieve complex tissue formation in vitro. It has the potential to be used to study human developmental processes, as well as offering an animal free alternative method to the teratoma assay to assess the developmental potential of novel stem cell lines.

Fitbit Activity Trackers Interrupt Workplace Sedentary Behavior: A New Application.

This study investigated whether Fitbit devices can reduce sedentary behavior among employees in the workplace. Participants were asked to wear Fitbits during 8-hour work shifts, 5 days per week, for 8 weeks. They were instructed to stand at least once every 30 minutes throughout the workday. The goal of the study was to determine whether standing once every 30 minutes was a feasible strategy for reducing sedentary workplace behavior. On average, participants completed 36 of 40 workdays using Fitbits. The number of times participants stood during an 8-hour workday averaged 12 stands per day (maximum 16 stands per day). These results indicate that Fitbit technology is effective for recording and tracking interruptions in sitting time; however, to reduce sitting behavior, alternate approaches are required to motivate larger numbers of workers to participate.

CHD1 loss sensitizes prostate cancer to DNA damaging therapy by promoting error-prone double-strand break repair.

BACKGROUND: Deletion of the chromatin remodeler chromodomain helicase DNA-binding protein 1 (CHD1) is a common genomic alteration found in human prostate cancers (PCas). CHD1 loss represents a distinct PCa subtype characterized by SPOP mutation and higher genomic instability. However, the role of CHD1 in PCa development in vivo and its clinical utility remain unclear. PATIENTS AND METHODS: To study the role of CHD1 in PCa development and its loss in clinical management, we generated a genetically engineered mouse model with prostate-specific deletion of murine Chd1 as well as isogenic CHD1 wild-type and homozygous deleted human benign and PCa lines. We also developed patient-derived organoid cultures and screened patients with metastatic PCa for CHD1 loss. RESULTS: We demonstrate that CHD1 loss sensitizes cells to DNA damage and causes a synthetic lethal response to DNA damaging therapy in vitro, in vivo, ex vivo, in patient-derived organoid cultures and in a patient with metastatic PCa. Mechanistically, CHD1 regulates 53BP1 stability and CHD1 loss leads to decreased error-free homologous recombination (HR) repair, which is compensated by increased error-prone non-homologous end joining (NHEJ) repair for DNA double-strand break (DSB) repair. CONCLUSIONS: Our study provides the first in vivo and in patient evidence supporting the role of CHD1 in DSB repair and in response to DNA damaging therapy. We uncover mechanistic insights that CHD1 modulates the choice between HR and NHEJ DSB repair and suggest that CHD1 loss may contribute to the genomic instability seen in this subset of PCas.

Prospective controlled cohort study of Troponin I levels in patients undergoing elective spine surgery for degenerative conditions: Prone versus supine position.

Prior studies have suggested that elevated serum Troponin-I (TnI) levels immediately after non-cardiac surgical procedures (8-40%) represent subclinical cardiac stress which independently predicts increased 30-day mortality. Routine post-operative TnI monitoring has therefore been suggested as a standard of care. However, no prior studies have focussed on elective degenerative spine surgery, whilst few have measured pre-op TnI. Further, prolonged prone positioning could represent an additional, independent, cardiac stress. We planned a prospective controlled cohort study of consecutive TnI levels in routine elective spine surgery for degenerative spine conditions, incorporating 3 groups: 'prone<2h', 'prone>2h' and 'supine' positioning. TnI levels (>0.04µg/L) were recorded immediately pre-/post-surgery, and by 24h of surgery. N=120 patients were recruited. Complete results were obtained in 92 (39 supine, 53 prone). No significant between-groups differences were observed in demographic or cardiovascular risk factors. Validated TnI-elevation by 24h was not observed in any group. Spurious elevations were recorded in one 'prone<2h' and one 'prone>2h'. One non-ST segment myocardial infarction (STEMI) occurred on day 7 without TnI elevation by 24h (prone>2h). There was no 30-day mortality. CONCLUSIONS: Despite a lower cut-off, no validated TnI elevation was observed in any group by 24h after surgery. One non-STEMI had not been associated with TnI-elevation by 24h. Immediately peri-operative cardiac stress therefore appeared comparatively rare in patients undergoing routine elective spine surgery. Further, prone positioning did not represent an additional, independent, risk. Routine immediately post-operative TnI monitoring in elective spine surgery therefore appears unjustified. Our study highlighted several caveats regarding consecutive TnI testing.

HPV16 oncogene expression levels during early cervical carcinogenesis are determined by the balance of epigenetic chromatin modifications at the integrated virus genome.

In cervical squamous cell carcinomas, high-risk human papillomavirus (HRHPV) DNA is usually integrated into host chromosomes. Multiple integration events are thought to be present within the cells of a polyclonal premalignant lesion and the features that underpin clonal selection of one particular integrant remain poorly understood. We previously used the W12 model system to generate a panel of cervical keratinocyte clones, derived from cells of a low-grade premalignant lesion naturally infected with the major HRHPV type, HPV16. The cells were isolated regardless of their selective advantage and differed only by the site of HPV16 integration into the host genome. We used this resource to test the hypothesis that levels of HPV16 E6/E7 oncogene expression in premalignant cells are regulated epigenetically. We performed a comprehensive analysis of the epigenetic landscape of the integrated HPV16 DNA in selected clones, in which levels of virus oncogene expression per DNA template varied ~6.6-fold. Across the cells examined, higher levels of virus expression per template were associated with more open chromatin at the HPV16 long control region, together with greater loading of chromatin remodelling enzymes and lower nucleosome occupancy. There were higher levels of histone post-translational modification hallmarks of transcriptionally active chromatin and lower levels of repressive hallmarks. There was greater abundance of the active/elongating form of the RNA polymerase-II enzyme (RNAPII-Ser2P), together with CDK9, the component of positive transcription elongation factor b complex responsible for Ser2 phosphorylation. The changes observed were functionally significant, as cells with higher HPV16 expression per template showed greater sensitivity to depletion and/or inhibition of histone acetyltransferases and CDK9 and less sensitivity to histone deacetylase inhibition. We conclude that virus gene expression per template following HPV16 integration is determined through multiple layers of epigenetic regulation, which are likely to contribute to selection of individual cells during cervical carcinogenesis.

Evidence that small molecule enhancement of ß-hexosaminidase activity corrects the behavioral phenotype in Dutch APP(E693Q) mice through reduction of ganglioside-bound Aß.

Certain mutant Alzheimer's amyloid-ß (Aß) peptides (that is, Dutch mutant APP(E693Q)) form complexes with gangliosides (GAß). These mutant Aß peptides may also undergo accelerated aggregation and accumulation upon exposure to GM2 and GM3. We hypothesized that increasing ß-hexosaminidase (ß-hex) activity would lead to a reduction in GM2 levels, which in turn, would cause a reduction in Aß aggregation and accumulation. The small molecule OT1001 is a ß-hex-targeted pharmacological chaperone with good bioavailability, blood-brain barrier penetration, high selectivity for ß-hex and low cytotoxicity. Dutch APP(E693Q) transgenic mice accumulate oligomeric Aß as they age, as well as Aß oligomer-dose-dependent anxiety and impaired novel object recognition (NOR). Treatment of Dutch APP(E693Q) mice with OT1001 caused a dose-dependent increase in brain ß-hex levels up to threefold over those observed at baseline. OT1001 treatment was associated with reduced anxiety, improved learning behavior in the NOR task and dramatically reduced GAß accumulation in the subiculum and perirhinal cortex, both of which are brain regions required for normal NOR. Pharmacological chaperones that increase ß-hex activity may be useful in reducing accumulation of certain mutant species of Aß and in preventing the associated behavioral pathology.

ASC deficiency suppresses proliferation and prevents medulloblastoma incidence.

Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is silenced by promoter methylation in many types of tumors, yet ASC's role in most cancers remains unknown. Here, we show that ASC is highly expressed in a model of medulloblastoma, the most common malignant pediatric brain cancer; ASC is also expressed in human medulloblastomas. Importantly, while ASC deficiency did not affect normal cerebellar development, ASC knockout mice on the Smoothened (ND2:SmoA1) transgenic model of medulloblastoma exhibited a profound reduction in medulloblastoma incidence and a delayed tumor onset. A similar decrease in tumorigenesis with ASC deficiency was also seen in the hGFAP-Cre:SmoM2 mouse model of medulloblastoma. Interestingly, hyperproliferation of the external granule layer (EGL) was comparable at P20 in both wild-type and ASC-deficient SmoA1 mice. However, while the apoptosis and differentiation markers remained unchanged at this age, proliferation makers were decreased, and the EGL was reduced in thickness and area by P60. This reduction in proliferation with ASC deficiency was also seen in isolated SmoA1 cerebellar granule precursor cells in vitro, indicating that the effect of ASC deletion on proliferation was cell autonomous. Interestingly, ASC-deficient SmoA1 cerebella exhibited disrupted expression of genes in the transforming growth factor-ß pathway and increased level of nuclear Smad3. Taken together, these results demonstrate an unexpected role for ASC in Sonic hedgehog-driven medulloblastoma tumorigenesis, thus identifying ASC as a promising novel target for antitumor therapy.

Immunomodulation and AD--down but not out.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common cause of dementia in the elderly. Interventions that remove existing fibrillar and oligomeric amyloid-ß (Aß) are believed to be essential for the success of any attempt at stabilization of brain function and mitigation of cognitive decline. Many of these strategies have focused on Aß vaccination and administration of anti-Aß antibodies. Both active and passive immunotherapies have been successful in mouse models, but both have had limited effect in clinical trials. Intravenous immunoglobulin (IVIG) has been proposed as a potential treatment for AD following evidence for behavioral benefit in AD models and cognitive benefit in early phase 1 and phase 2 clinical trials. A phase 3 trial IVIG trial failed to meet its primary outcomes. While there was a statistically significant benefit in moderate stage AD patients who carried an APOE ε4 allele, this stabilization of cognition was evident only on neuropsychological examination. No benefit on activities of daily living was evident, therefore failing to qualify AD as a new indication for IVIG. Identifying the biologically active component (s) responsible for the neuropsychological benefit in APOE ε4-positive AD patients could enable the development of a compound with greater potency that would qualify for FDA (US Food and Drug Administration) registration.

Impact of gavage dosing procedure and gastric content on adverse respiratory effects and mortality in rat toxicity studies.

Unscheduled mortality preceded by adverse respiratory clinical signs in rats dosed by oral gavage may not only be caused by technical gavage error or systemic toxicity but may also be caused by gastro-esophageal reflux and subsequent aspiration of high concentrations of drug formulation. In a 3 week oral gavage rat toxicity study for an early drug development compound, preterminal deaths (approximately 20% of animals) at high doses (≥1000 mg kg(-1) ) and concentrations (≥60 mg ml(-1) ) were preceded by recurrent dyspnea, rales or excessive salivation, without evidence of accidental intrapulmonary gavage error. Histological evaluation revealed extensive necrosis and inflammatory changes in the upper respiratory tract, especially in the nasal turbinates and/or nasopharynx. The presence of food particles in inflammatory exudates suggested a retrograde aspiration of stomach content with test formulation via the nasopharyngeal duct into the posterior region of the nose. In contrast, no mortality or adverse respiratory effects were observed in rats following 2 week intravenous administration at comparable exposures or oral gavage administration at lower concentrations (≤20 mg ml(-1) ). In a pharmacology study, the compound caused a dose-dependent increase in gastric content (partly due to inhibition of gastric emptying), providing a pharmacological basis for the suspected gavage-mediated gastroesophageal reflux. Reducing the dose volume and dosing fasted animals substantially reduced or eliminated the respiratory effects and mortality at the high test article concentrations, demonstrating that the adverse effects are related to the gavage method.

Evaluation of terminology used to describe disorders of sex development.

OBJECTIVE: The terminology used to describe abnormalities of sex determination and sex differentiation was revised in 2006. It was anticipated that new terms, such as 'disorders of sex development' (DSD), would improve communication between health professionals, aid parental understanding and be acceptable to affected individuals. The purpose of this study was to evaluate the success of the new terminology. SUBJECTS AND METHODS: Using a questionnaire, we evaluated the acceptance of these new terms by parents of children with a DSD (n = 19), health professionals (n = 15) and parents of unaffected children (n = 25). RESULTS: Comparing the term 'DSD' to 'intersex', overall 86.4% of participants preferred the term 'DSD', and parents of a child with a DSD had an even higher preference (94.7%). Parents of an affected child considered the new term to improve their understanding of their child's condition (83.3%), and to aid explanation by parent to affected child (82.4%) and to wider family and friends (84.2%). Health professionals preferred the genotype-based terms, whereas parents considered these terms confusing. Overall, 59.3% of participants agreed DSD was an acceptable new term. CONCLUSIONS: There was broad support for the new terminology by parents and health professionals. The description 'disorder of sex development' may be helpful to parents at the time when it is not possible to assign gender, after which aetiologically based diagnoses should be used where possible.

Oral anticoagulation in atrial fibrillation: A pan-European patient survey.

BACKGROUND: Anticoagulation with vitamin K antagonists (VKAs) provides effective stroke prophylaxis in patients with atrial fibrillation (AF). Optimisation of such therapy requires frequent monitoring, dose adjustments and stringent lifestyle restrictions. We conducted a large multinational survey in patients with chronic AF to gain insights into their perceptions and understanding of VKA use. METHODS: Eligible patients were adults with AF who had been prescribed VKAs for at least 1 year. A total of 711 patient interviews were conducted in seven European countries during June and July 2004. RESULTS: The majority of patients (58% male; mean age 68 years) claimed to understand their treatment programme; despite this, only 7% knew that VKA use is aimed at preventing strokes and 24% stated that they would have liked more information. Patients attended an average of 14 monitoring sessions in the previous year; however, 21% missed appointments, especially younger patients (<65 years). The International Normalized Ratio (INR) was within the target range in most or all of the last five to ten visits in 64% of patients; nonetheless, 38% were not aware that an INR outside the target range is associated with health risks. On average, patients required dose adjustments every four sessions. VKA treatment impacted 67% of patients in terms of diet, socialising, career and independence, especially younger patients (74%). CONCLUSIONS: Monitoring, dose adjustments and lifestyle restrictions to optimise the intensity of anticoagulation with VKAs are problematic for patients with AF, and their knowledge of the consequences of such therapy is often poor.

Ventilator-dependent survivors of catastrophic illness transferred to 23 long-term care hospitals for weaning from prolonged mechanical ventilation.

STUDY OBJECTIVES: This multicenter study was undertaken to characterize the population of ventilator-dependent patients admitted to long-term care hospitals (LTCHs) for weaning from mechanical ventilation. DESIGN: Observational study with concurrent data collection. Characteristics of the LTCHs were also surveyed. SETTING: Twenty-three LTCHs in the United States. PATIENTS: Consecutive ventilator-dependent patients admitted over a 1-year period: March 1, 2002, to February 28, 2003. RESULTS: A total of 1,419 patients were enrolled in the Ventilation Outcomes Study. Median age of the patients was 71.8 years old (range, 18 to 97.7 years), with an equal gender distribution. The premorbid domicile was home or assisted living in 86.5%; "good" premorbid functional status (Zubrod score 0-2) was assessed in 77%. There was a history of smoking in 59% (mean, 57 +/- 42 pack-years [+/- SD]); premorbid diagnoses averaged 2.6 per patient. Patients came to the LTCH after mean of 33.8 +/- 29 days at the transferring hospital; mean time to tracheotomy was 15.0 +/- 10 days. A medical illness led to ventilator dependency in 60.8% of patients; a surgical procedure led to ventilatory dependency in 39.2%. On admission to the LTCH, the median acute physiology score of APACHE (acute physiology and chronic health evaluation) III was 35 (range, 4 to 115); > 90% of patients had at least three penetrating indwelling tubes/catheters; 42% of patients had stage 2 or higher pressure ulceration. CONCLUSIONS: This is the first multicenter study to characterize ventilator-dependent survivors of catastrophic illness admitted to the post-ICU venue of LTCHs for weaning from prolonged mechanical ventilation (PMV). Overall, our findings suggest that ventilator-dependent patients admitted to LTCHs for weaning will continue to require considerable medical interventions and treatments, owing to the burden of acute-on-chronic diseases resulting in PMV.

Post-ICU mechanical ventilation at 23 long-term care hospitals: a multicenter outcomes study.

STUDY OBJECTIVES: This multicenter study was undertaken to characterize the population of ventilator-dependent patients admitted to long-term care hospitals (LTCHs) with weaning programs, and to report treatments, complications, weaning outcome, discharge disposition, and survival in these patients. DESIGN: Observational study with concurrent data collection. SETTING: Twenty-three LTCHs in the United States. PATIENTS: Consecutive ventilator-dependent patients admitted over a 1-year period: March 1, 2002, to February 28, 2003. RESULTS: A total of 1,419 patients were enrolled in the Ventilation Outcomes Study. Median age of patients was 71.8 years (range, 18 to 97.7 years). Patients averaged 6.9 procedures and treatments during the LTCH hospitalization; median length of stay was 40 days (range, 1 to 365 days). Seven of the 10 most frequent complications treated at the LTCH were infections; congestive heart failure and diabetes mellitus were the most common comorbidities requiring treatment. Outcomes of weaning attempts, scored at LTCH discharge, were 54.1% weaned, 20.9% ventilator dependent, and 25.0% deceased. Median time to wean (n = 766) was 15 days (range, 7 to 30 days). Discharge disposition included 28.8% to home, 49.2% to rehabilitation and extended-care facilities, and 19.5% to short-stay acute hospitals. Nearly one third of patients were known to be alive 12 months after admission to the LTCH. CONCLUSIONS: Patients admitted to LTCHs for weaning attempts were elderly, with acute-on-chronic diseases, and continued to require considerable medical interventions and treatments. The frequency and type of complications were not surprising following prolonged and aggressive ICU interventions. In the continuum of critical care medicine, more than half of ventilator-dependent survivors of catastrophic illness transferred from the ICU were successfully weaned from prolonged mechanical ventilation in the setting of an LTCH.

Marker-based quantitative genetics in the wild?: the heritability and genetic correlation of chemical defenses in eucalyptus.

Marker-based methods for estimating heritability and genetic correlation in the wild have attracted interest because traditional methods may be impractical or introduce bias via G x E effects, mating system variation, and sampling effects. However, they have not been widely used, especially in plants. A regression-based approach, which uses a continuous measure of genetic relatedness, promises to be particularly appropriate for use in plants with mixed-mating systems and overlapping generations. Using this method, we found significant narrow-sense heritability of foliar defense chemicals in a natural population of Eucalyptus melliodora. We also demonstrated a genetic basis for the phenotypic correlation underlying an ecological example of conditioned flavor aversion involving different biosynthetic pathways. Our results revealed that heritability estimates depend on the spatial scale of the analysis in a way that offers insight into the distribution of genetic and environmental variance. This study is the first to successfully use a marker-based method to measure quantitative genetic parameters in a tree. We suggest that this method will prove to be a useful tool in other studies and offer some recommendations for future applications of the method.

A Welch-type test for homogeneity of contrasts under heteroscedasticity with application to meta-analysis.

A common problem that arises in the meta-analysis of several studies, each with independent treatment and control groups, is to test for the homogeneity of effect sizes without the assumptions of equal variances of the treatment and the control groups and of equal variances among the separate studies. A commonly used test statistic, frequently denoted as Q, is the weighted sum of squares of the differences of the individual effect sizes from the mean effect size, with weights inversely proportional to the variances of the effect sizes. The primary contributions of this article are the presentation of improved and very accurate approximations to the distributions of the Q statistic when the effect size is a linear contrast such as the difference between the treatment and control means. Our improved approximation to the distribution of Q under the null hypothesis is based on a multiple of an F-distribution; its use yields a substantial reduction in the type I error rate of the homogeneity test. Our improved approximation to the distribution of Q under an alternative hypothesis is based on a shift of a chi-square distribution; its use allows for much greater accuracy in the computation of the power of the homogeneity test. These two improved approximate distributions are developed using the Welch methodology of approximating the moments of Q by the use of multivariate Taylor expansions. The quality of these approximations is studied by simulation. A secondary contribution of this article is a study of how best to combine the variances of the treatment and control groups (needed for the calculation of weights in the Q statistic). Our conclusion, based on simulations, is that use of pooled variances can result in substantially erroneous conclusions.

Prolonged cardiac repolarisation during spontaneous nocturnal hypoglycaemia in children and adolescents with type 1 diabetes.

AIMS/HYPOTHESIS: It has been postulated that hypoglycaemia-related cardiac dysrhythmia and, in particular, prolonged cardiac repolarisation, may contribute to increased mortality rates in children and adolescents with type 1 diabetes. METHODS: We examined the prevalence of prolonged QT interval on ECG during spontaneous hypoglycaemia in 44 type 1 diabetic subjects (aged 7-18 years), and explored the relationships between serial overnight measurements of QT interval corrected for heart rate (QTc) and serum glucose, potassium and epinephrine levels. Each subject underwent two overnight profiles; blood was sampled every 15 min for glucose measurements and hourly for potassium and epinephrine. Serial ECGs recorded half-hourly between 23.00 and 07.00 hours were available on 74 nights: 29 with spontaneous hypoglycaemia (defined as blood glucose <3.5 mmol/l) and 45 without hypoglycaemia. RESULTS: Mean overnight QTc was longer in females than in males (412 vs 400 ms, p=0.02), but was not related to age, diabetes duration or HbA(1)c. Prolonged QTc (>440 ms) occurred on 20 out of 74 (27%) nights, with no significant differences between male and female subjects, and was more prevalent on nights with hypoglycaemia (13/29, 44%) than on nights without (7/45, 15%, p=0.0008). Potassium levels were lower on nights when hypoglycaemia occurred (minimum potassium 3.4 vs 3.7 mmol/l, p=0.0003) and were inversely correlated with maximum QTc (r=-0.40, p=0.03). In contrast, epinephrine levels were not higher on nights with hypoglycaemia and were not related to QTc. CONCLUSIONS/INTERPRETATION: In young type 1 diabetic subjects, prolonged QTc occurred frequently with spontaneous overnight hypoglycaemia and may be related to insulin-induced hypokalaemia.

Orthopaedic intervention in early rheumatoid arthritis. Occurrence and predictive factors in an inception cohort of 1064 patients followed for 5 years.

OBJECTIVES: To assess the occurrence of and predictive factors for orthopaedic surgery in an inception cohort of rheumatoid arthritis (RA) patients recruited and followed prospectively for 5 yr in nine regions in England. METHODS: Standard clinical, laboratory and radiological assessments and all interventions were recorded at baseline and yearly in RA patients (less than 2 yrs symptoms) prior to the use of disease-modifying drugs. RESULTS: One thousand and sixty-four patients completed 5 yr of follow-up. Two hundred and sixty-four orthopaedic procedures for RA were performed in 181 (17%) patients at a median of 36.5 months from baseline. Seventy-five (7%) had replacements of major joints. Risk factors at baseline for large joint replacement surgery were a low haemoglobin concentration [odds ratio scores (OR) 3.4, 95% confidence interval (CI) 2.1-5.8] and high scores for erythrocyte sedimentation rate (ESR) (OR 3.2, CI 1.8-5.3), disease activity (DAS) (OR 2.1, CI 1.2-3.5) and Larsen X-rays (OR 2.6, CI 1.4-4.8). For hand or foot joint surgery (4%), risk factors included female gender (OR 3.2, CI 1.3-7.6), joint score (OR 2.3, CI 1.2-4.3), erosions (OR 2.3, CI 1.1-4.8), DAS (OR 2.4, 1.3-4.5) and Health Assessment Questionnaire score (OR 1.9, CI 1.0-3.6). No significant associations were seen for tendon, soft tissue or other minor procedures (6%). The HLA-DRB1 RA shared epitope was associated with any type of orthopaedic surgery (OR 1.7, CI 1.1-2.7). CONCLUSIONS: Eleven per cent of RA patients treated with conventional drug therapy for 5 yr underwent large- or small-joint surgery, an outcome which could be compared against that for new disease-modifying drugs. Risk factors varied according to type of surgery, but included standard clinical and laboratory measures. In order to reduce the eventual need for surgery, a therapeutic target in the first year of RA is the suppression of disease activity, as measured by haemoglobin and ESR. These are useful details for clinicians, health professionals and patients.