A novel ACVR1 mutation in the glycine/serine-rich domain found in the most benign case of a fibrodysplasia ossificans progressiva variant reported to date

Fibrodysplasia Ossificans Progressiva (FOP) is a rare, autosomal dominant condition, classically characterised by heterotopic ossification beginning in childhood and congenital great toe malformations; occurring in response to a c.617 G>A ACVR1 mutation in the functionally important glycine/serine-rich domain of exon 6. Here we describe a novel c.587 T>C mutation in the glycine/serine-rich domain of ACVR1, associated with delayed onset of heterotopic ossification and an exceptionally mild clinical course. Absence of great toe malformations, the presence of early ossification of the cervical spine facets joints, plus mild bilateral camptodactyly of the 5th fingers, together with a novel ACVR1 mutation, are consistent with the 'FOP-variant' syndrome. The c.587 T>C mutation replaces a conserved leucine with proline at residue 196. Modelling of the mutant protein reveals a steric clash with the kinase domain that will weaken interactions with FKBP12 and induce exposure of the glycine/serine-rich repeat. The mutant receptor is predicted to be hypersensitive to ligand stimulation rather than being constitutively active, consistent with the mild clinical phenotype. This case extends our understanding of the 'FOP-variant' syndrome.

PTHR1 polymorphisms influence BMD variation through effects on the growing skeleton

We investigated whether polymorphisms in PTHR1 are associated with bone mineral density (BMD), to determine whether the association of this gene with BMD was due to effects on attainment of peak bone mass or effects on subsequent bone loss. The PTHR1 gene, including its 14 exons, their exon-intron boundaries, and 1,500 bp of its promoter region, was screened for polymorphisms by denaturing high-performance liquid chromatography (dHPLC) and sequencing in 36 osteoporotic cases. Eleven single-nucleotide polymorphisms (SNPs), one tetranucleotide repeat, and one tetranucleotide deletion were identified. A cohort of 634 families, including 1,236 men (39%) and 1,926 women (61%) ascertained with probands with low BMD (Z< -2.0) and the Children in Focus subset of the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort (785 unrelated individuals, mean age 118 months), were genotyped for the five most informative SNPs (minor allele frequency >5%) and the tetranucleotide repeat. In our osteoporosis families, association was noted between lumbar spine BMD and alleles of a known functional tetranucleotide repeat (U4) in the PTHR1 promoter region (P = 0.042) and between two and three marker haplotypes of PTHR1 polymorphisms with lumbar spine, femoral neck, and total hip BMD (P = 0.021-0.047). This association was restricted to the youngest tertile of the population (age 16-39 years, P = 0.013-0.048). A similar association was found for the ALSPAC cohort: two marker haplotypes of SNPs A48609T and C52813T were associated with height (P = 0.006) and total body less head BMD (P = 0.02), corrected for age and gender, confirming the family findings. These findings suggest a role for PTHR1 variation in determining peak BMD.

Use of observed within-person variation of cardiac troponin in emergency department patients for determination of biological variation and percentage and absolute reference change values

BACKGROUND Many patients presenting to the emergency department (ED) for assessment of possible acute coronary syndrome (ACS) have low cardiac troponin concentrations that change very little on repeat blood draw. It is unclear if a lack of change in cardiac troponin concentration can be used to identify acutely presenting patients at low risk of ACS. METHODS We used the hs-cTnI assay from Abbott Diagnostics, which can detect cTnI in the blood of nearly all people. We identified a population of ED patients being assessed for ACS with repeat cTnI measurement who ultimately were proven to have no acute cardiac disease at the time of presentation. We used data from the repeat sampling to calculate total within-person CV (CV(T)) and, knowing the assay analytical CV (CV(A)), we could calculate within-person biological variation (CV(i)), reference change values (RCVs), and absolute RCV delta cTnI concentrations. RESULTS We had data sets on 283 patients. Men and women had similar CV(i) values of approximately 14%, which was similar at all concentrations <40 ng/L. The biological variation was not dependent on the time interval between sample collections (t = 1.5-17 h). The absolute delta critical reference change value was similar no matter what the initial cTnI concentration was. More than 90% of subjects had a critical reference change value <5 ng/L, and 97% had values of <10 ng/L. CONCLUSIONS With this hs-cTnI assay, delta cTnI seems to be a useful tool for rapidly identifying ED patients at low risk for possible ACS.

High-resolution SNP microarray investigation of copy number variations on chromosome 18 in a control cohort

Copy number variations (CNVs) as described in the healthy population are purported to contribute significantly to genetic heterogeneity. Recent studies have described CNVs using lymphoblastoid cell lines or by application of specifically developed algorithms to interrogate previously described data. However, the full extent of CNVs remains unclear. Using high-density SNP array, we have undertaken a comprehensive investigation of chromosome 18 for CNV discovery and characterisation of distribution and association with chromosome architecture. We identified 399 CNVs, of which loss represents 98%, 58% are less than 2.5 kb in size and 71% are intergenic. Intronic deletions account for the majority of copy number changes with gene involvement. Furthermore, one-third of CNVs do not have putative breakpoints within repetitive sequences. We conclude that replicative processes, mediated either by repetitive elements or microhomology, account for the majority of CNVs in the healthy population. Genomic instability involving the formation of a non-B structure is demonstrated in one region.

Identification of IL6R and chromosome 11q13.5 as risk loci for asthma

We aimed to identify novel genetic variants affecting asthma risk, since these might provide novel insights into molecular mechanisms underlying the disease. We did a genome-wide association study (GWAS) in 2669 physician-diagnosed asthmatics and 4528 controls from Australia. Seven loci were prioritised for replication after combining our results with those from the GABRIEL consortium (n=26 475), and these were tested in an additional 25 358 independent samples from four in-silico cohorts. Quantitative multi-marker scores of genetic load were constructed on the basis of results from the GABRIEL study and tested for association with asthma in our Australian GWAS dataset. Two loci were confirmed to associate with asthma risk in the replication cohorts and reached genome-wide significance in the combined analysis of all available studies (n=57 800): rs4129267 (OR 1·09, combined p= 2·4×10-8) in the interleukin-6 receptor (IL6R) gene and rs7130588 (OR 1·09, p=1·8×10-8) on chromosome 11q13.5 near the leucine-rich repeat containing 32 gene (LRRC32, also known as GARP). The 11q13.5 locus was significantly associated with atopic status among asthmatics (OR 1·33, p=7×10-4), suggesting that it is a risk factor for allergic but not non-allergic asthma. Multi-marker association results are consistent with a highly polygenic contribution to asthma risk, including loci with weak effects that might be shared with other immune-related diseases, such as NDFIP1, HLA-B, LPP, and BACH2. The IL6R association further supports the hypothesis that cytokine signalling dysregulation affects asthma risk, and raises the possibility that an IL6R antagonist (tocilizumab) may be effective to treat the disease, perhaps in a genotype-dependent manner. Results for the 11q13.5 locus suggest that it directly increases the risk of allergic sensitisation which, in turn, increases the risk of subsequent development of asthma. Larger or more functionally focused studies are needed to characterise the many loci with modest effects that remain to be identified for asthma. National Health and Medical Research Council of Australia. A full list of funding sources is provided in the webappendix. © 2011 Elsevier Ltd.

An innovative online intervention: The Steering Clear First Offender Drink Driving Program

Drink driving remains a substantial public health issue warranting investigation. First offender drink drivers are seen to be less risky than repeat offenders, though the majority of first offenders report drink driving prior to detection, and many continue to drink drive following conviction. Few first offenders are offered treatment programs, and as such there is a need to address drink driving behaviour at this stage. A comprehensive approach including first offender treatment is needed to address the problem. Online interventions have demonstrated effectiveness in reducing risky behaviours such as harmful substance use. Such interventions allow for personalised tailored content to be delivered to individuals targeting specific mechanisms of behavioural change. This method also allows for targeting screening to ensure relevance of content on an individual level. However, there have been no research based online programs to date aimed at reducing repeat drink driving by first offenders. The Steering Clear First Offender Drink Driving Program is a self-guided, research based online program aimed at reducing recidivism by first time drink driving offenders. It includes a specialised web app to track drinks and build plans to prevent future drink driving. This allows for elongation of learning and encouragement of sustained behavioural change using self-monitoring after initial program completion. An outline of the program is discussed and the qualitative experience of the program on a sample of first offenders recruited at the time of court appearance is described.

Can nurses do more for patients to reduce vascular access and cardiac complications following PCI?

Percutaneous coronary interventions have increased 50% in Australia, yet vascular and cardiac complications remain ongoing outcome issues for patients. Managing complications is confounded by reduced length of patient stay, yet is an integral component of a cardiac nurses’ scope of practice. The aim of this study was to highlight in and out of hospital vascular and cardiac complications, for twelve months post patient discharge after PCI. Prospective data was collected from the hospital angioplasty database from 1089 consecutive patients who had PCI procedures from 1 January 2005 to 31 December 2006. In hospital vascular complications were reported by 391 (35%) of the 1089 patients, following PCI. Of these, 22.4% had haemorrhage only, 7.1% haematoma only. Cardiac complications in hospital were, one death (0.09%) following PCI, three deaths (0.27%) during the same admission and no incidence of myocardial infarction or bypass surgery. Patients who had PCI in 2005 (525) were telephone followed up after discharge at one and twelve months. Surprisingly, ongoing vascular outcomes were noted, with a 2.5% incidence at one month and 4% at 12 months. Cardiac complications were also identified, 51 (9.7%) patients requiring readmission for repeat angiogram, 19 (3.6%) a repeat PCI and 7 (1.3%) patients undergoing bypass surgery. This review highlights that vascular and cardiac problems are ongoing issues for PCI patients both in and out of hospital. The results suggest that cardiac nurses focus more on improving the monitoring and discharge care of patients and families for recovery after PCI.

Structures of three different neutral polysaccharides of Acinetobacter baumannii, NIPH190, NIPH201, and NIPH615, assigned to K30, K45, and K48 capsule types, respectively, based on capsule biosynthesis gene clusters

Neutral capsular polysaccharides (CPSs) were isolated from Acinetobacter baumannii NIPH190, NIPH201, and NIPH615. The CPSs were found to contain common monosaccharides only and to be branched with a side-chain 1→3-linked β-d-glucopyranose residue. Structures of the oligosaccharide repeat units (K units) of the CPSs were elucidated by 1D and 2D 1H and 13C NMR spectroscopy. Novel CPS biosynthesis gene clusters, designated KL30, KL45, and KL48, were found at the K locus in the genome sequences of NIPH190, NIPH201, and NIPH615, respectively. The genetic content of each gene cluster correlated with the structure of the CPS unit established, and therefore, the capsular types of the strains studied were designated as K30, K45, and K48, respectively. The initiating sugar of each K unit was predicted, and glycosyltransferases encoded by each gene cluster were assigned to the formation of the linkages between sugars in the corresponding K unit.

Structural determination of the K14 capsular polysaccharide from an ST25 Acinetobacter baumannii isolate, D46

The structure of the capsular polysaccharide (CPS) recovered from D46, an extensively antibiotic resistant ST25 Acinetobacter baumannii clinical isolate, was elucidated. The structure was resolved on the basis of NMR spectroscopy and chemical analyses, and was found to contain a branched neutral pentasaccharide with a backbone composed of GalpNAc and Galp residues, all d configured, and a d-Glcp side group. The KL14 gene cluster found in the D46 genome includes genes for four glycosyltransferases but no modules for synthesis of complex sugars, and this is consistent with the structure of K14. The K14 structure and KL14 sequence clarify the relationship between the structure and K locus sequence for A. nosocomialis isolate LUH5541. The identity of the first sugar of the K14 repeat unit (K unit), and the functions of the four encoded glycosyltransferases and Wzy polymerase were predicted.

Treatment failure in celiac disease due to coexistent exocrine pancreatic insufficiency

A 17-year-old white adolescent had a history of chronic diarrhea, delayed puberty, and growth failure. Investigations excluded cystic fibrosis, Shwachman syndrome, and endocrine causes of growth failure. Severe steatorrhea was diagnosed from fecal fat studies, and a jejunal suction biopsy showed total villus atrophy, consistent with a diagnosis of celiac diseases. Following introduction of a gluten-free diet, his appetite and growth improved, but he continued to have abdominal discomfort and loose offensive bowel motions. One year later, severe steatorrhea was present. A repeat jejunal biopsy showed partial recovery of villus architecture. Serum immunoreactive trypsinogen level was low, which was highly suggestive of exocrine pancreatic failure. Results of quantitative pancreatic stimulation test confirmed the presence of primary pancreatic insufficiency. After introduction of oral pancreatic enzyme supplements with meals, his gastrointestinal symptoms resolved and growth velocity accelerated. Previously, primary pancreatic insufficiency has only been described in elderly patients with long-standing untreated celiac disease. This case, however, emphasizes that pancreatic failure can occur with celiac disease at any age. Determination of a serum immunoreactive trypsinogen level should be considered a useful screening tool for pancreatic insufficiency in patients with celiac disease who have not responded to a gluten-free diet.

Structure of the K12 capsule containing 5,7-di-N-acetylacinetaminic acid from Acinetobacter baumannii isolate D36

The repeat unit of the K12 capsular polysaccharide isolated from the Acinetobacter baumannii global clone 1 clinical isolate, D36, was elucidated by means of chemical and spectroscopical methods. The structure was shown to contain N-acetyl-D-galactosamine (D-GalpNAc), N-acetyl-D-fucosamine and N-acetyl-L-fucosamine linked together in the main chain, with the novel sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulosonic acid (5,7-di-N-acetylacinetaminic acid or Aci5Ac7Ac), attached to D-GalpNAc as a side branch. This matched the sugar composition of the K12 capsule and the genetic content of the KL12 capsule gene cluster reported previously. D-FucpNAc was predicted to be the substrate for the initiating transferase, ItrB3, with the Wzy polymerase making a α-D-FucpNAc-(1 → 3)-D-GalpNAc linkage between the repeat units. The three glycosyltransferases encoded by KL12 are all retaining glycosyltransferases and were predicted to form specific linkages between the sugars in the K12 repeat unit.

Strong evidence for a novel schizophrenia risk locus on chromosome 1p31.1 in homogeneous pedigrees from Tamil Nadu, India

OBJECTIVE: The study of ethnically homogeneous populations may help to identify schizophrenia risk loci. The authors conducted a genomewide linkage scan for schizophrenia in an Indian population. METHOD: Participants were 441 individuals (262 affected probands and siblings) who were recruited primarily from one ethnically homogeneous group, the Tamil Brahmin caste, although individuals from other geographically proximal castes also participated. Genotyping of 124 affected sibling pair pedigrees was performed with 402 short tandem repeat polymorphisms. Linkage analyses were conducted using nonparametric exponential LOD (logarithm of the odds ratio for linkage) scores and parametric heterogeneity LOD scores. Parametric heterogeneity scores were calculated using simple dominant and recessive models, correcting for multiple statistics. The data were examined for evidence of consanguinity. Genomewide significance levels were determined using 10,000 gene dropping simulations. RESULTS: These findings revealed genomewide significant linkage to chromosome 1p31.1, through the use of both exponential and heterogeneity LOD scores, incorporating correction for multiple statistics and mild consanguinity. The estimated sibling recurrence risk associated with this putative locus was 1.95. Analysis for heterogeneity LOD scores also detected suggestive linkage to chromosomes 13q22.1 and 16q12.2. Using 117 tag single nucleotide polymorphisms (SNPs), family-based association analyses of phosphodiesterase 4B (PDE4B), the closest schizophrenia candidate gene, detected no convincing evidence of association, suggesting that the chromosome 1 peak represents a novel risk locus. CONCLUSIONS: This is the first study-to the authors' knowledge-to report significant linkage of schizophrenia to chromosome 1p31.1. Further investigation of this chromosome region in diverse populations is warranted to identify underlying sequence variants.

On the probability of dizygotic twins being concordant for two alleles at multiple polymorphic loci

Accurate determination of same-sex twin zygosity is important for medical, scientific and personal reasons. Determination may be based upon questionnaire data, blood group, enzyme isoforms and fetal membrane examination, but assignment of zygosity must ultimately be confirmed by genotypic data. Here methods are reviewed for calculating average probabilities of correctly concluding a twin pair is monozygotic, given they share the same genotypes across all loci for commonly utilized multiplex short tandem repeat (STR) kits.

Fine-tuning of unmanned aerial surveillance for ecological systems

Much of our understanding and management of ecological processes requires knowledge of the distribution and abundance of species. Reliable abundance or density estimates are essential for managing both threatened and invasive populations, yet are often challenging to obtain. Recent and emerging technological advances, particularly in unmanned aerial vehicles (UAVs), provide exciting opportunities to overcome these challenges in ecological surveillance. UAVs can provide automated, cost-effective surveillance and offer repeat surveys for pest incursions at an invasion front. They can capitalise on manoeuvrability and advanced imagery options to detect species that are cryptic due to behaviour, life-history or inaccessible habitat. UAVs may also cause less disturbance, in magnitude and duration, for sensitive fauna than other survey methods such as transect counting by humans or sniffer dogs. The surveillance approach depends upon the particular ecological context and the objective. For example, animal, plant and microbial target species differ in their movement, spread and observability. Lag-times may exist between a pest species presence at a site and its detectability, prompting a need for repeat surveys. Operationally, however, the frequency and coverage of UAV surveys may be limited by financial and other constraints, leading to errors in estimating species occurrence or density. We use simulation modelling to investigate how movement ecology should influence fine-scale decisions regarding ecological surveillance using UAVs. Movement and dispersal parameter choices allow contrasts between locally mobile but slow-dispersing populations, and species that are locally more static but invasive at the landscape scale. We find that low and slow UAV flights may offer the best monitoring strategy to predict local population densities in transects, but that the consequent reduction in overall area sampled may sacrifice the ability to reliably predict regional population density. Alternative flight plans may perform better, but this is also dependent on movement ecology and the magnitude of relative detection errors for different flight choices. Simulated investigations such as this will become increasingly useful to reveal how spatio-temporal extent and resolution of UAV monitoring should be adjusted to reduce observation errors and thus provide better population estimates, maximising the efficacy and efficiency of unmanned aerial surveys.

Does the addition of Clonidine to lumbar nerve root blocks improve outcome? A randomised, prospective, single-blinded controlled pilot study

Purpose To evaluate if adding clonidine to a standard nerve root block containing local anaesthetic and steroid improved the outcome of patients with severe lumbar nerve root pain secondary to MRI proven lumbar disc prolapse. Methods We undertook a single blind, prospective, randomised controlled trial evaluating 100 consecutive patients with nerve root pain secondary to lumbar disc prolapse undergoing trans-foraminal epidural steroid injection either with or without the addition of clonidine. 50 patients were allocated to each arm of the study. The primary outcome measure was the avoidance of a second procedure- repeat injection or micro-discectomy surgery. Secondary outcome measures were also studied: pain scores for leg and back pain using a visual analogue scale (VAS), the Roland Morris Disability Questionnaire (RMDQ) and the Measure Your Own Medical Outcome Profile (MYMOP). Follow up was carried out at 6 weeks, 6 months and 1 year. Results No serious complications occurred. Of the 50 patients who received the addition of clonidine, 56% were classified as successful injections, with no further intervention required, as opposed to 40% who received the standard injection. This difference did not reach statistical significance (p=0.109, chi-squared test). All secondary measures showed no statistically significant differences between the groups except curiously, the standard group who had been classified as successful had better leg pain relief than the clonidine group (p=0.026) at 1 year. Conclusions This pilot study has shown a 16% treatment effect with adding clonidine to lumbar nerve root blocks and that it is a safe injectate for this purpose.