Using Genetics to Inform Interventions Related to Sodium and Potassium in Hypertension.

BACKGROUND: Hypertension is a key risk factor for major adverse cardiovascular events but remains difficult to treat in many individuals. Dietary interventions are an effective approach to lower blood pressure (BP) but are not equally effective across all individuals. BP is heritable, and genetics may be a useful tool to overcome treatment response heterogeneity. We investigated whether the genetics of BP could be used to identify individuals with hypertension who may receive a particular benefit from lowering sodium intake and boosting potassium levels. METHODS: In this observational genetic study, we leveraged cross-sectional data from up to 296 475 genotyped individuals drawn from the UK Biobank cohort for whom BP and urinary electrolytes (sodium and potassium), biomarkers of sodium and potassium intake, were measured. Biologically directed genetic scores for BP were constructed specifically among pathways related to sodium and potassium biology (pharmagenic enrichment scores), as well as unannotated genome-wide scores (conventional polygenic scores). We then tested whether there was a gene-by-environment interaction between urinary electrolytes and these genetic scores on BP. RESULTS: Genetic risk and urinary electrolytes both independently correlated with BP. However, urinary sodium was associated with a larger BP increase among individuals with higher genetic risk in sodium- and potassium-related pathways than in those with comparatively lower genetic risk. For example, each SD in urinary sodium was associated with a 1.47-mm Hg increase in systolic BP for those in the top 10% of the distribution of genetic risk in sodium and potassium transport pathways versus a 0.97-mm Hg systolic BP increase in the lowest 10% (P=1.95×10-3). This interaction with urinary sodium remained when considering estimated glomerular filtration rate and indexing sodium to urinary creatinine. There was no strong evidence of an interaction between urinary sodium and a standard genome-wide polygenic score of BP. CONCLUSIONS: The data suggest that genetic risk in sodium and potassium pathways could be used in a precision medicine model to direct interventions more specifically in the management of hypertension. Intervention studies are warranted.

Mycobacteriophage Alexphander Gene 94 Encodes an Essential dsDNA-Binding Protein during Lytic Infection.

Mycobacteriophages are viruses that specifically infect bacterial species within the genera Mycobacterium and Mycolicibacterium. Over 2400 mycobacteriophages have been isolated on the host Mycolicibacterium smegmatis and sequenced. This wealth of genomic data indicates that mycobacteriophage genomes are diverse, mosaic, and contain numerous (35-60%) genes for which there is no predicted function based on sequence similarity to characterized orthologs, many of which are essential to lytic growth. To fully understand the molecular aspects of mycobacteriophage-host interactions, it is paramount to investigate the function of these genes and gene products. Here we show that the temperate mycobacteriophage, Alexphander, makes stable lysogens with a frequency of 2.8%. Alexphander gene 94 is essential for lytic infection and encodes a protein predicted to contain a C-terminal MerR family helix-turn-helix DNA-binding motif (HTH) and an N-terminal DinB/YfiT motif, a putative metal-binding motif found in stress-inducible gene products. Full-length and C-terminal gp94 constructs form high-order nucleoprotein complexes on 100-500 base pair double-stranded DNA fragments and full-length phage genomic DNA with little sequence discrimination for the DNA fragments tested. Maximum gene 94 mRNA levels are observed late in the lytic growth cycle, and gene 94 is transcribed in a message with neighboring genes 92 through 96. We hypothesize that gp94 is an essential DNA-binding protein for Alexphander during lytic growth. We proposed that gp94 forms multiprotein complexes on DNA through cooperative interactions involving its HTH DNA-binding motif at sites throughout the phage chromosome, facilitating essential DNA transactions required for lytic propagation.

Overweight or obesity increases the risk of cardiovascular disease among older Australian adults, even in the absence of cardiometabolic risk factors: a Bayesian survival analysis from the Hunter Community Study.

OBJECTIVE: To estimate the risk of cardiovascular disease (CVD) in older adults with overweight or obesity without metabolic risk factors using a Bayesian survival analysis. DESIGN: Prospective cohort study with median follow-up of 9.7 years. SETTING: Newcastle, New South Wales, Australia. PARTICIPANTS: A total of 2313 community-dwelling older men and women. INTERVENTION/EXPOSURE: Participants without known CVD and with a body mass index (BMI) ≥ 18.5 kg m2 were stratified by BMI and metabolic risk to create six BMI-metabolic health categories. Metabolic risk was defined according to the International Diabetes Federation criteria for metabolic syndrome. 'Metabolically healthy' was defined as absence of metabolic risk factors. Bayesian survival analysis, incorporating prior information from a previously published meta-analysis was used to assess the effect of BMI-metabolic health categories on time from recruitment to CVD. MAIN OUTCOME: Incident physician-diagnosed CVD, defined as fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, angina, or coronary revascularisation procedure, was determined by linkage to hospital admissions records and Medicare Australia data. Secondary outcomes were cardiovascular mortality and all-cause mortality. RESULTS: From 2313 adults with complete metabolic health data over a median follow-up of 9.7 years, 283 incident CVD events, 58 CVD related deaths and 277 deaths from any cause occurred. In an adjusted Bayesian survival model of complete cases with informative prior and metabolically healthy normal weight as the reference group, the risk of CVD was increased in metabolically healthy overweight (HR = 1.52, 95% credible interval 0.96-2.36), and in metabolically healthy obesity (HR = 1.86, 95% credible interval 1.14-3.08). Imputation of missing metabolic health and confounding data did not change the results. CONCLUSION: There was increased risk of CVD in older adults with overweight or obesity, even in the absence of any metabolic abnormality. This argues against the notion of 'metabolically healthy' overweight or obesity.

Prevalence and clinical risk prediction of hypertriglyceridaemia in a community cohort.

BACKGROUND: Hypertriglyceridaemia (HTG; defined as ≥1.7 mmol/L) has a prevalence of 18-33% with significant inter-regional variation. Despite meta-analysis demonstrating its association with increased risk of cardiovascular disease, only 40% of HTG is identified in the community resulting in underutilisation of lipid-lowering therapy and specialist clinics. An increase in awareness of its clinical risk factors is needed to improve the identification and management of HTG to prevent cardiovascular risk. AIMS: To evaluate the prevalence, distribution and clinical predictors of HTG ≥1.7 mmol/L in a representative community group. METHODS: Data were obtained from the Hunter Community Study (HCS), a longitudinal cohort of community-dwelling men and women aged 55-85 years residing in Newcastle, New South Wales. Fasting triglycerides were identified based on the availability of fasting blood glucose level and categorised according to normal (<1.7 mmol/L), mild (1.7 to <2.3 mmol/L) and moderate-severe HTG (≥2.3 mmol/L). Clinical predictors of HTG were assessed using linear and logistic regression models. RESULTS: Of 2536 triglyceride levels, 2216 (87%) were in a fasting state and included in the study. Three hundred and two (13.6%) participants had mild HTG and 221 (10.0%) participants had moderate-severe HTG. Significant clinical predictors of HTG included male gender, increasing body mass index, current smoking, decreasing daily step counts, increasing fasting glucose and higher thyroid-stimulating hormone. Alcohol intake and blood pressure were not significant in either adjusted regression model. CONCLUSIONS: HTG ≥1.7 mmol/L is common, affecting 24% of the HCS. Clinical predictors identify modifiable risk factors for cardiovascular risk management. Clinician education to promote awareness is required to improve patient outcomes.

Validity of three risk prediction models for dementia or cognitive impairment in Australia.

BACKGROUND: no studies have compared the predictive validity of different dementia risk prediction models in Australia. OBJECTIVES: (i) to investigate the predictive validity of the Australian National University-Alzheimer's Disease Risk Index (ANU-ADRI), LIfestyle for BRAin Health (LIBRA) Index and cardiovascular risk factors, ageing and dementia study (CAIDE) models for predicting probable dementia/cognitive impairment in an Australian cohort. (ii) To develop and assess the predictive validity of a new hybrid model combining variables from the three models. METHODS: the Hunter Community Study (HCS) included 3,306 adults aged 55-85 years with a median follow-up of 7.1 years. Probable dementia/cognitive impairment was defined using Admitted Patient Data Collection, dispensing of cholinesterase inhibitors or memantine, or a cognitive test. Model validity was assessed by calibration and discrimination. A hybrid model was developed using deep neural network analysis, a machine learning method. RESULTS: 120 (3.6%) participants developed probable dementia/cognitive impairment. Mean calibration by ANU-ADRI, LIBRA, CAIDE and the hybrid model was 19, 0.5, 4.7 and 3.4%, respectively. The discrimination of the models was 0.65 (95% CI 0.60-0.70), 0.65 (95% CI 0.60-0.71), 0.54 (95% CI 0.49-0.58) and 0.80 (95% CI 0.78-0.83), respectively. CONCLUSION: ANU-ADRI and LIBRA were better dementia prediction tools than CAIDE for identification of high-risk individuals in this cohort. ANU-ADRI overestimated and LIBRA underestimated the risk. The new hybrid model had a higher predictive performance than the other models but it needs to be validated independently in longitudinal studies.

Developing clinical indicators for oncology: the inaugural cancer care indicator set for the Australian Council on Healthcare Standards.

INTRODUCTION: The Australian Council on Healthcare Standards (ACHS) sponsored an expert-led, consensus-driven, four-stage process, based on a modified Delphi methodology, to determine a set of clinical indicators as quality measures of cancer service provision in Australia. This was done in response to requests from institutional health care providers seeking accreditation, which were additional and complementary to the existing radiation oncology set. The steering group members comprised multidisciplinary key opinion leaders and a consumer representative. Five additional participants constituted the stakeholder group, who deliberated on the final indicator set. METHODS AND RECOMMENDATIONS: An initial meeting of the steering group scoped the high level nature of the desired set. In stage 2, 65 candidate indicators were identified by a literature review and a search of international metrics. These were ranked by survey, based on ease of data accessibility and collectability and clinical relevance. The top 27 candidates were debated by the stakeholder group and culled to a final set of 16 indicators. A user manual was created with indicators mapped to clinical codes. The indicator set was ratified by the Clinical Oncology Society of Australia and is now available for use by health care organisations participating in the ACHS Clinical Indicator Program. This inaugural cancer clinical indicator set covers high level assessment of various critical processes in cancer service provision in Australia. Regular reviews and updates will ensure usability. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This is the inaugural indicator set for cancer care for use across Australia and internationally under the ACHS Clinical Indicator Program. Multidisciplinary involvement through a modified Delphi process selected indicators representing both generic and specific aspects of care across the cancer journey pathway and will provide a functional tool to compare health care delivery across multiple settings. It is anticipated that this will drive continual improvement in cancer care provision.

Cooperative DNA binding by proteins through DNA shape complementarity.

Localized arrays of proteins cooperatively assemble onto chromosomes to control DNA activity in many contexts. Binding cooperativity is often mediated by specific protein-protein interactions, but cooperativity through DNA structure is becoming increasingly recognized as an additional mechanism. During the site-specific DNA recombination reaction that excises phage λ from the chromosome, the bacterial DNA architectural protein Fis recruits multiple λ-encoded Xis proteins to the attR recombination site. Here, we report X-ray crystal structures of DNA complexes containing Fis + Xis, which show little, if any, contacts between the two proteins. Comparisons with structures of DNA complexes containing only Fis or Xis, together with mutant protein and DNA binding studies, support a mechanism for cooperative protein binding solely by DNA allostery. Fis binding both molds the minor groove to potentiate insertion of the Xis ß-hairpin wing motif and bends the DNA to facilitate Xis-DNA contacts within the major groove. The Fis-structured minor groove shape that is optimized for Xis binding requires a precisely positioned pyrimidine-purine base-pair step, whose location has been shown to modulate minor groove widths in Fis-bound complexes to different DNA targets.

Control of DNA minor groove width and Fis protein binding by the purine 2-amino group.

The width of the DNA minor groove varies with sequence and can be a major determinant of DNA shape recognition by proteins. For example, the minor groove within the center of the Fis-DNA complex narrows to about half the mean minor groove width of canonical B-form DNA to fit onto the protein surface. G/C base pairs within this segment, which is not contacted by the Fis protein, reduce binding affinities up to 2000-fold over A/T-rich sequences. We show here through multiple X-ray structures and binding properties of Fis-DNA complexes containing base analogs that the 2-amino group on guanine is the primary molecular determinant controlling minor groove widths. Molecular dynamics simulations of free-DNA targets with canonical and modified bases further demonstrate that sequence-dependent narrowing of minor groove widths is modulated almost entirely by the presence of purine 2-amino groups. We also provide evidence that protein-mediated phosphate neutralization facilitates minor groove compression and is particularly important for binding to non-optimally shaped DNA duplexes.

Metabolic Health, Overweight or Obesity, and Depressive Symptoms among Older Australian Adults.

BACKGROUND: The relationship between overweight or obesity and depressive symptoms in individuals with or without cardio-metabolic abnormalities is unclear. In a cross-sectional study we examined the odds of experiencing depressive symptoms in overweight or obese older adults with or without metabolic abnormalities. METHODS: The participants included 3318 older adults from the Hunter Community Study Cohort with a Body Mass Index (BMI) ≥ 18.5 kgm2, stratified by BMI and metabolic health risk. Obesity was defined as BMI ≥ 30 kgm2 and metabolically healthy as the absence of metabolic risk factors, according to International Diabetic Federation criteria for metabolic syndromes. Moderate to severe depressive symptoms were defined as a Centre for Epidemiological Studies Depression Scale (CES-D) score ≥ 16. RESULTS: Compared to the metabolically healthy normal weight (MHNW) group, the odds of experiencing moderate/severe depressive symptoms were higher in those classified as a metabolically unhealthy normal weight (MUNW) (odds ratio (OR) = 1.25, 95% Confidence Interval (CI): 0.76-2.06) or metabolically unhealthy obesity (MUO) (OR = 1.48, 95% CI: 1.00-2.19), but not in those classified as metabolically unhealthy overweight (MUOW) (OR = 0.96, 95% CI: 0.63-1.45), metabolically healthy overweight (MHOW) (OR = 0.80, 95% CI: 0.51-1.26), and metabolically healthy obesity (MHO) (OR = 1.03, 95% CI: 0.65-1.64). Compared with MHNW males, the odds of moderate/severe depressive symptoms were increased in all other BMI category-metabolic health groups for males and females. LIMITATIONS: Our relatively small sample size and cross-sectional design did not allow us to robustly establish causality. CONCLUSION: The odds of experiencing moderate/severe depressive symptoms were increased in metabolically unhealthy older adults regardless of normal weight or obesity, with the odds of having moderate/severe depressive symptoms being higher in females than in males.

Putative pseudolysogeny-dependent phage gene implicated in the superinfection resistance of Cutibacterium acnes.

Objectives: Cutibacterium acnes, formerly Propionibacterium acnes, is a bacterial species characterized by tenacious acne-contributing pathogenic strains. Therefore, bacteriophage therapy has become an attractive treatment route to circumvent issues such as evolved bacterial antibiotic resistance. However, medical and commercial use of phage therapy for C. acnes has been elusive, necessitating ongoing exploration of phage characteristics that confer bactericidal capacity. Methods: A novel phage (Aquarius) was isolated and analyzed. Testing included genomic sequencing and annotation, electron microscopy, patch testing, reinfection assays, and qPCR to confirm pseudolysogeny and putative superinfection exclusion (SIE) protein expression. Results: Given a superinfection-resistant phenotype was observed, reinfection assays and patch tests were performed, which confirmed the re-cultured bacteria were resistant to superinfection. Subsequent qPCR indicated pseudolysogeny was a concomitantly present phenomenon. Phage genomic analysis identified the presence of a conserved gene (gp41) with a product containing Ltp family-like protein signatures which may contribute to phage-mediated bacterial superinfection resistance (SIR) in a pseudolysogeny-dependent manner. qPCR was performed to analyze and roughly quantify gp41 activity, and mRNA expression was high during infection, implicating a role for the protein during the phage life cycle. Conclusions: This study confirms that C. acnes bacteria are capable of harboring phage pseudolysogens and suggests that this phenomenon plays a role in bacterial SIR. This mechanism may be conferred by the expression of phage proteins while the phage persists within the host in the pseudolysogenic state. This parameter must be considered in future endeavors for efficacious application of C. acnes phage-based therapeutics.

Can critical care transport be safely reduced in children intubated during emergency management of status epilepticus in the United Kingdom: a national audit with case-control analysis.

OBJECTIVE: This study describes the baseline clinical characteristics, predictors of successful extubation at referring hospitals and short-term outcomes of children intubated for status epilepticus and referred to United Kingdom (UK) paediatric critical care transport teams (PCCTs). DESIGN: Multicentre audit with case-control analysis, conducted between 1 September 2018 and 1 September 2020. SETTING: This study involved 10 UK PCCTs. PATIENTS: Children over 1 month of age intubated during emergency management for status epilepticus (SE), referred to UK PCCTs. Patients with trauma, requiring time-critical neurosurgical intervention or those with a tracheostomy were excluded. INTERVENTIONS: No interventions were implemented. MEASUREMENTS AND MAIN RESULTS: Out of the 1622 referrals for SE, 1136 (70%) were intubated at referral. The median age was 3 years (IQR 1.25-6.54 years). Among the intubated children, 396 (34.8%) were extubated locally by the referring team, with 19 (4.8%) requiring reintubation. Therefore, the overall rate of successful extubation was 33% (377/1136). There was significant variation between PCCTs, with local extubation rates ranging from 2% to 74%. Multivariable analyses showed region/PCCT, contributing diagnosis, acute changes on CT, preceding encephalopathy and type of continuous sedation (midazolam) used postintubation were significantly associated with transfer to a critical care unit. CONCLUSION: This study highlights wide regional variation in early extubation practices. Regions with high successful extubation rates have established extubation guidelines from PCCTs. Successful extubation represents critical care transports that have been avoided.

Using clinical indicators to facilitate quality improvement via the accreditation process: an adaptive study into the control relationship.

OBJECTIVE: The aim of the study was to determine accreditation surveyors' and hospitals' use and perceived usefulness of clinical indicator reports and the potential to establish the control relationship between the accreditation and reporting systems. The control relationship refers to instructional directives, arising from appropriately designed methods and efforts towards using clinical indicators, which provide a directed moderating, balancing and best outcome for the connected systems. DESIGN: Web-based questionnaire survey. SETTING: Australian Council on Healthcare Standards' (ACHS) accreditation and clinical indicator programmes. RESULTS: Seventy-three of 306 surveyors responded. Half used the reports always/most of the time. Five key messages were revealed: (i) report use was related to availability before on-site investigation; (ii) report use was associated with the use of non-ACHS reports; (iii) a clinical indicator set's perceived usefulness was associated with its reporting volume across hospitals; (iv) simpler measures and visual summaries in reports were rated the most useful; (v) reports were deemed to be suitable for the quality and safety objectives of the key groups of interested parties (hospitals' senior executive and management officers, clinicians, quality managers and surveyors). CONCLUSIONS: Implementing the control relationship between the reporting and accreditation systems is a promising expectation. Redesigning processes to ensure reports are available in pre-survey packages and refined education of surveyors and hospitals on how to better utilize the reports will support the relationship. Additional studies on the systems' theory-based model of the accreditation and reporting system are warranted to establish the control relationship, building integrated system-wide relationships with sustainable and improved outcomes.

The risk of coronary thrombosis with cyclo-oxygenase-2 inhibitors does not vary with polymorphisms in two regions of the cyclo-oxygenase-2 gene.

AIMS: To investigate whether polymorphisms of the cyclo-oxygenase-2 (COX-2) gene modify the adverse cardiovascular effects of COX-2 inhibitors. METHODS: A case control study was conducted in the Hunter Region of New South Wales, Australia. Cases (n= 460) were hospitalized with acute coronary syndrome (ACS). Controls (n= 640) were recruited from the electoral rolls. Structured interviews gathered information on variables including recent ingestion of non-steroidal anti-inflammatory drugs (NSAIDs). Targeted genotyping of rs 20417(G > C) and rs5275 (T > C) polymorphisms was performed by real-time polymerase chain reaction using allele-specific probes. RESULTS: Ingestion of any NSAID in the week prior to interview was associated with an elevated risk for ACS: adjusted odds ratio 1.8 (1.2, 2.5). The rs 20417 and rs 5275 polymorphisms were not singly associated with risk for ACS: adjusted odds ratios 1.1 (0.80, 1.5) and 1.2 (0.88, 1.5), respectively. Individually, the polymorphisms did not modify the risk of ACS with the drugs. When analyses were conducted by haplotype, the adjusted odds ratio with celecoxib or rofecoxib in individuals who had one or two copies of the 'low risk' haplotype (no GT) was 1.2 (0.29, 5.0), compared with 2.1 (1.1, 4.0) with the 'high risk' haplotype (one or two copies of GT). CONCLUSIONS: We found little evidence of a gene/drug interaction. We found a statistically non-significant trend toward a lower risk of coronary events with NSAIDs in the presence of the 'low risk' haplotype. Even if confirmed, the clinical utility of the finding would be limited as this haplotype is carried by a minority of the population.

Genetic association and causal inference converge on hyperglycaemia as a modifiable factor to improve lung function.

Measures of lung function are heritable, and thus, we sought to utilise genetics to propose drug-repurposing candidates that could improve respiratory outcomes. Lung function measures were found to be genetically correlated with seven druggable biochemical traits, with further evidence of a causal relationship between increased fasting glucose and diminished lung function. Moreover, we developed polygenic scores for lung function specifically within pathways with known drug targets and investigated their relationship with pulmonary phenotypes and gene expression in independent cohorts to prioritise individuals who may benefit from particular drug-repurposing opportunities. A transcriptome-wide association study (TWAS) of lung function was then performed which identified several drug-gene interactions with predicted lung function increasing modes of action. Drugs that regulate blood glucose were uncovered through both polygenic scoring and TWAS methodologies. In summary, we provided genetic justification for a number of novel drug-repurposing opportunities that could improve lung function.

Chronic respiratory disorders like asthma affect around 600 million people worldwide. Although these illnesses are widespread, they can have several different underlying causes, making them difficult to treat. Drugs that work well on one type of respiratory disorder may be completely ineffective on another. Understanding the biological and environmental factors that cause these illnesses will allow them to be treated more effectively by tailoring therapies to each patient. Reduced lung function is a factor in respiratory disorders and it can have many genetic causes. Studying the genes of patients with reduced lung function can reveal the genes involved, some of which may already be targets of existing drugs for other illnesses. So, could a patient's genetics be used to repurpose existing drugs to treat their respiratory disorders? Reay et al. combined three methods to link genetics and biological processes to the causes of reduced lung function. The results reveal several factors that could lead to new treatments. In one example, reduced lung function showed a link to genes associated with high blood sugar. As such, treatments used in diabetes might help improve lung function in some patients. Reay et al. also developed a scoring system that could predict the efficacy of a treatment based on a patient's genetics. The study suggests that COVID-19 infection could be affected by blood sugar levels too. Chronic respiratory disorders are a critical issue worldwide and have proven difficult to treat, but these results suggest a way to identify new therapies and target them to the right patients. The findings also support a connection between lung function and blood sugar levels. This implies that perhaps existing diabetes treatments ­ including diet and lifestyle changes aimed at reducing or limiting blood sugar ­ could be repurposed to treat respiratory disorders in some patients. The next step will be to perform clinical trials to test whether these therapies are in fact effective.

Serum L-arginine and endogenous methylarginine concentrations predict irritable bowel syndrome in adults: A nested case-control study.

BACKGROUND & AIMS: Nitric oxide, a major inhibitory nonadrenergic, noncholinergic neurotransmitter that relaxes smooth muscle, may be implicated in the pathophysiology of visceral hypersensitivity in irritable bowel syndrome (IBS). Impaired bioavailability of the nitric oxide precursor molecule L-arginine and higher concentrations of methylarginines (endogenous inhibitors of nitric oxide synthesis) are known to impair nitric oxide synthesis in numerous gastrointestinal cell types. We therefore examined serum concentrations of L-arginine and the methylarginines in a nested case-control study, to assess whether these factors are associated with adult IBS. METHODS: Data on clinical characteristics, methylarginines, and L-arginine (measured using LC-MS/MS) were collected from a random population-based cohort of Australian adults (median age = 64 years; IQR = 60-70). Cases of IBS, defined according to Rome III criteria (N = 156), and controls (N = 332) were identified from within the cohort at the 5-year follow-up. RESULTS: In adjusted logistic regression analyses, L-arginine, asymmetric dimethylarginine, symmetric dimethylarginine, L-arginine/asymmetric dimethylarginine ratio, and Kessler-10 psychological distress scores were significantly associated with IBS (p < 0.05). [Correction added on 18 September 2021, after first online publication: In the preceding sentence, the value (p > 0.05) has been changed to (p < 0.05)]. Similar results were found for IBS subtypes. Higher serum L-arginine concentration had the strongest association with IBS diagnosis, with an odds ratio of 9.03 for those with serum L-arginine at the 75th (84 µmol/L) versus 25th (46 µmol/L) percentile (95% CI: 5.99-13.62). L-arginine had the best discriminative ability with a bias-adjusted area under the receiver operator characteristic curve of 0.859. CONCLUSIONS: Higher serum concentrations of L-arginine and endogenous methylarginines are strongly associated with IBS in adults.

The effect of inhaled corticosteroids on bone mineral density measured by quantitative ultrasonography in an older population.

INTRODUCTION: Prolonged use of systemic corticosteroids leads to reduced bone mineral density and osteoporosis, in turn increasing the risk of minimal trauma fractures with their associated morbidity and mortality in elderly populations. However, the effect of inhaled corticosteroids on bone mineral density has been debated in the medical literature. OBJECTIVES: We aimed to determine the effect of inhaled corticosteroids on bone mineral density measured using calcaneal quantitative ultrasonography in a cohort of older Australians. METHODS: Data was collected from the Hunter Community Study, a longitudinal cohort of Australians aged 55-85. Simple and multiple linear regression methods were used to test the cross-sectional association between inhaled corticosteroids and calcaneal bone mineral density measured with quantitative ultrasound at baseline. A causal diagram was used to determine the minimally sufficient number of co-variates necessary to determine the unconfounded effect of inhaled corticosteroids on bone mineral density; these included gender, body mass index, smoking, asthma, alcohol use, age, physical activity, and diet. RESULTS: There were 152 (6.8%) patients on inhaled corticosteroids and 2098 (93%) controls. Simple and multiple linear regression methods showed a non-significant effect of inhaled steroids on BMD with slight decrease of BMD -0.010 g/cm2 (95% CI -0.042 to 0.022, P = .55) and -0.013 g/cm2 (95% CI -0.062 to 0.036, P = .61) respectively. Age, gender, body mass index, and smoking were stronger predictors of BMD. CONCLUSIONS: No statistically significant relationship was detected between the use of inhaled corticosteroids and reduced bone mineral density in this observational study of a cohort of older Australians.

Multiple serine transposase dimers assemble the transposon-end synaptic complex during IS607-family transposition.

IS607-family transposons are unusual because they do not have terminal inverted repeats or generate target site duplications. They encode two protein-coding genes, but only tnpA is required for transposition. Our X-ray structures confirm that TnpA is a member of the serine recombinase (SR) family, but the chemically-inactive quaternary structure of the dimer, along with the N-terminal location of the DNA binding domain, are different from other SRs. TnpA dimers from IS1535 cooperatively associate with multiple subterminal repeats, which together with additional nonspecific binding, form a nucleoprotein filament on one transposon end that efficiently captures a second unbound end to generate the paired-end complex (PEC). Formation of the PEC does not require a change in the dimeric structure of the catalytic domain, but remodeling of the C-terminal α-helical region is involved. We posit that the PEC recruits a chemically-active conformer of TnpA to the transposon end to initiate DNA chemistry.

Pneumococcal polysaccharide vaccine associated with reduced lengths of stay for cardiovascular events hospital admissions: Experience from the Hunter Community Study.

BACKGROUND: The pneumococcal polysaccharide vaccine (PPV) has been associated with reduced risk of cardiovascular events in human observational studies. Animal studies suggest that the phosphorylcholine epitope in the Streptococcus pneumoniae cell wall is structurally similar to oxidized low-density lipoprotein (oxLDL), hence PPV induces the production of antibodies that cross-react with anti-oxLDL and may cause regression of atherosclerotic plaque. We set out to determine the strength of association between PPV administration and reduction in cardiovascular events. METHODS: A longitudinal, population-based cohort study of older Australians, from the Hunter Community Study, with up to 11 years of follow-up. We included participants aged ≥ 65 years at baseline (2004-2008), without a history of cardiovascular disease (CVD). History of PPV administration at baseline was the main exposure of interest. "Total number of hospital bed-days with CVD primary diagnosis" was one of the main outcomes measured. Models were adjusted for age, diabetes, alcohol intake, and smoking status. Influenza vaccine was the control exposure used and fracture bed-days was the control outcome used, to investigate the potential for residual confounding. RESULTS: 91 of the total 1074 participants (mean age = 72, male = 45%) experienced a CVD event during follow-up. PPV (regardless of influenza vaccine) was associated with a significant reduction in CVD bed-day, (n = 863, incident rate ratio, IRR = 0.65, 95%CI: 0.45-0.94, p = 0.02), but influenza vaccine (regardless of PPV) was not (n = 864, IRR = 0.86, 95%CI: 0.54-1.35, p = 0.51). Furthermore, PPV adjusted for influenza vaccine remained associated with CVD bed-days (IRR = 0.64, 95%CI: 0.43-0.96, p = 0.03) but was not associated with fracture bed-days (IRR = 0.75, 95%CI: 0.28-2.00, p = 0.56). CONCLUSION: PPV demonstrated a 35% reduction in CVD bed-days. This finding was robust to residual confounding, using a control exposure and a control outcome, eliminating the concern for healthy-user bias. A large double-blinded placebo-controlled RCT is underway to confirm our finding and to explore the proposed mechanism of action (ACTRN12615000536561).

A Serological Diagnosis of Coeliac Disease Is Associated with Osteoporosis in Older Australian Adults.

Previously thought to be mainly a disorder of childhood and early adult life, coeliac disease (CeD) is increasingly diagnosed in older adults. This may be important given the association between CeD and osteoporosis. The primary aim of this study was to determine the seroprevalence of undiagnosed CeD (‘at-risk serology’) in an older Australian community and relate this to a diagnosis of osteoporosis and fractures during a follow-up period of 12 years. We included participants from the Hunter Community Study (2004⁻2007) aged 55⁻85, who had anti-tissue transglutaminase (tTG) titres, human leukocyte antigen (HLA) genotypes, and bone mineral density measurements at baseline. Follow-up data included subsequent diagnosis of CeD and fractures using hospital information. ‘At-risk’ serology was defined as both tTG and HLA positivity. Complete results were obtained from 2122 patients. The prevalence of ‘at-risk’ serology was 5%. At baseline, 3.4% fulfilled criteria for a diagnosis of osteoporosis. During a mean of 9.7 years of follow-up, 7.4% of the cohort suffered at least one fracture and 0.7% were subsequently diagnosed with CeD. At-risk serology was significantly associated with osteoporosis in a multivariate model (odds ratio 2.83, 95% confidence interval 1.29⁻6.22); there was insufficient power to look at the outcome of fractures. The results of this study demonstrate that at-risk CeD serology was significantly associated with concurrent osteoporosis but not future fractures. Most individuals with a serological diagnosis of CeD were not diagnosed with CeD during the follow-up period according to medical records. Coeliac disease likely remains under-diagnosed.