Associations of blood glucose and prevalent diabetes with risk of cardiovascular disease in 500 000 adult Chinese: the China Kadoorie Biobank

AIMS

To examine the relationship of self-reported diabetes, and of random blood glucose levels among individuals without known diabetes, with the prevalence of cardiovascular disease in Chinese adults.

METHODS

We examined cross-sectional data from the China Kadoorie Biobank of 0.5 million people aged 30-79 years recruited from 10 diverse regions of China in the period 2004-2008. Logistic regression was used to estimate the odds ratios of prevalent cardiovascular disease associated with self-reported diabetes, and with measured random blood glucose levels among participants with no history of diabetes, adjusting simultaneously for age, sex, area, education, smoking, alcohol, blood pressure and physical activity.

RESULTS

A total of 3.2% of participants had self-reported diabetes (men 2.9%; women 3.3%) and 2.8% had screen-detected diabetes (men 2.6%; women 2.8%), i.e. they had no self-reported history of diabetes but a blood glucose level suggestive of a diagnosis of diabetes. Compared with individuals without a history of diabetes, the odds ratios associated with self-reported diabetes were 2.18 (95% CI 2.06-2.30) and 1.88 (95% CI 1.75-2.01) for prevalent ischaemic heart disease and stroke/transient ischaemic attack, respectively. Among participants without self-reported diabetes there was a positive association between random blood glucose and ischaemic heart disease and stroke/transient ischaemic attack prevalence (P for trend <0.0001). Below the diabetic threshold (<11.1 mmol/l) each additional 1 mmol/l of random blood glucose was associated with 4% (95% CI 2-5%) and 5% (95% CI 3-7%) higher odds of prevalent ischaemic heart disease and stroke/transient ischaemic attack, respectively.

CONCLUSIONS

In this adult Chinese population, self-reported diabetes was associated with a doubling of the odds of prevalent cardiovascular disease. Below the threshold for diabetes there was still a modest, positive association between random blood glucose and prevalent cardiovascular disease.

Nursing home residents attending the emergency department: clinical characteristics and outcomes

Nursing home (NH) residents represent the frailest group of older people, and providing gerontologically attuned care that addresses these frailties is often a challenge within the emergency department (ED). This study sought to prospectively profile acutely unwell NH residents in order to clarify some of the challenges of providing emergency care to this group. Over an 18-week period, we prospectively reviewed all NH residents presenting to the ED of an urban university teaching hospital. Relevant data were retrieved by direct physician review (as part of a comprehensive geriatric assessment in the ED), collateral history from NH staff and primary carers, and review of electronic records. There were 155 ED visits by 116 NH residents. Their mean age was 80.3 (±9.6) years. High pre-morbid levels of dependency were reflected by a mean Barthel Index of 34.1 (±20) and almost two-thirds had a pre-existing diagnosis of dementia. One-third of visits were during 'normal' working hours. Patients were reviewed by their regular NH doctor pre-transfer for 36% of visits. Using accepted international criteria, over half of the visits were deemed 'potentially preventable'. Unwell NH residents have complex medical needs. The decision to refer these patients to the ED is often made by 'out of hours' general practitioners and their initial care in the ED is directed by physicians with limited experience in geriatric medicine. Most referrals to the ED are potentially preventable but this would require enhancements to the package of care available in NHs.

The molecular yo-yo method: live jump detection improves throughput of single-molecule force spectroscopy for out-of-equilibrium transitions

By monitoring multiple molecular transitions, force-clamp, and trap-position-clamp methods have led to precise determinations of the free energies and free energy landscapes for molecular states populated in equilibrium at the same or similar forces. Here, we present a powerful new elaboration of the force-clamp and force-jump methods, applicable to transitions far from equilibrium. Specifically, we have implemented a live jump detection and force-clamp algorithm that intelligently adjusts and maintains the force on a single molecule in response to the measured state of that molecule. We are able to collect hundreds of individual molecular transitions at different forces, many times faster than previously, permitting us to accurately determine force-dependent lifetime distributions and reaction rates. Application of our method to unwinding and rewinding the nucleosome inner turn, using optical tweezers reveals experimental lifetime distributions that comprise a statistically meaningful number of transitions, and that are accurately single exponential. These measurements significantly reduce the error in the previously measured rates, and demonstrate the existence of a single, dominant free energy barrier at each force studied. A key benefit of the molecular yo-yo method for nucleosomes is that it reduces as far as possible the time spent in the tangentially bound state, which minimizes the loss of nucleosomes by dissociation.

A new approach to HLA typing designed for solid organ transplantation: epityping and its application to the HLA-A locus

HLA-specific antibodies bind discrete clusters of amino acids called epitopes, but serological assignment of antibody specificities makes no reference to this. As HLA typing for solid organ transplantation is provided at only medium (serologically equivalent) resolution, this means that recipient HLA antibodies to donor HLA epitopes may not be identified. We have designed a novel and rapid HLA-A epitope typing method (epityping) using a two-stage PCR-SSP-based method to detect the HLA-A locus epitopes described by El Awar et al. 2007, Transplantation, 84, 532. The initial PCR step utilizes HLA-A locus-specific primers; the product is cleaned using the QIAquick Spin Purification procedure. The purified product is tested using our in-house epitope-specific primer panel, the results being visualized using gel electrophoresis. Twenty two UCLA DNA Exchange samples were epityped, blinded to the HLA type. Of the 75 primer pairs, the mean correlation coefficient was 0.95 with each sample giving 67 or more correct primer results. In all cases, it was possible to derive the first field classic HLA type from the epityping results. These results indicate that a method for identification of HLA epitopes which is comparable in time, cost and technical expertise to current HLA typing methods is achievable. Redesigning HLA typing to correlate with what the antibody binds should minimize inappropriate organ allocation. We suggest that epityping provides a more effective method than standard HLA typing for solid organ transplantation.

Unwinding and rewinding the nucleosome inner turn: force dependence of the kinetic rate constants

A simple model for the force-dependent unwinding and rewinding rates of the nucleosome inner turn is constructed and quantitatively compared to the results of recent measurements [A. H. Mack et al., J. Mol. Biol. 423, 687 (2012)]. First, a coarse-grained model for the histone-DNA free-energy landscape that incorporates both an elastic free-energy barrier and specific histone-DNA bonds is developed. Next, a theoretical expression for the rate of transitions across a piecewise linear free-energy landscape with multiple minima and maxima is presented. Then, the model free-energy landscape, approximated as a piecewise linear function, and the theoretical expression for the transition rates are combined to construct a model for the force-dependent unwinding and rewinding rates of the nucleosome inner turn. Least-mean-squares fitting of the model rates to the rates observed in recent experiments rates demonstrates that this model is able to well describe the force-dependent unwinding and rewinding rates of the nucleosome inner turn, observed in the recent experiments, except at the highest forces studied, where an additional ad hoc term is required to describe the data, which may be interpreted as an indication of an alternate high-force nucleosome disassembly pathway, that bypasses simple unwinding. The good agreement between the measurements and the model at lower forces demonstrates that both specific histone-DNA contacts and an elastic free-energy barrier play essential roles for nucleosome winding and unwinding, and quantifies their relative contributions.

Abstract P1-07-04: Comparison of HER2 expression by immunohistochemistry (IHC) using automated imaging system and fluorescence in situ hybridization (FISH). A retrospective analysis of 2853 cases

Background: Accurate assessment of HER2 status is critical for selecting patients who will benefit from trastuzumab therapy. There is still no consensus regarding the optimal method to assess HER2 status. Computerized image analysis has been shown to provide a more accurate and objective way for quantification of HER2 expression by IHC than manual evaluation. It has been suggested that the use of image analysis may help to resolve some of the discrepancies between IHC and FISH assay.

We compared the results of HER2 expression by IHC using automated image analysis with fluorescent in situ hybridization (FISH) assay.

Design: Testing for HER2 expression by IHC and FISH was performed on 2853 specimens at UT Southwestern Medical Center between the years 2002 to 2011. Quantification of IHC HER2 expression was done by image analysis and scored as positive (&gt;2.0), borderline (1.5 to 2.0) and negative. (&lt;1.5). The PathVysion kit was used for FISH assay to evaluate HER2 amplification. Ratios &gt;2.0, 1.8 to 2.0 and &lt;1.8 were defined positive, borderline and negative amplification respectively.

Results: IHC compared to FISH

Sexual dimorphism in healthy aging and mild cognitive impairment: a DTI study

Previous PET and MRI studies have indicated that the degree to which pathology translates into clinical symptoms is strongly dependent on sex with women more likely to express pathology as a diagnosis of AD, whereas men are more resistant to clinical symptoms in the face of the same degree of pathology. Here we use DTI to investigate the difference between male and female white matter tracts in healthy older participants (24 women, 16 men) and participants with mild cognitive impairment (21 women, 12 men). Differences between control and MCI participants were found in fractional anisotropy (FA), radial diffusion (DR), axial diffusion (DA) and mean diffusion (MD). A significant main effect of sex was also reported for FA, MD and DR indices, with male control and male MCI participants having significantly more microstructural damage than their female counterparts. There was no sex by diagnosis interaction. Male MCIs also had significantly less normalised grey matter (GM) volume than female MCIs. However, in terms of absolute brain volume, male controls had significantly more brain volume than female controls. Normalised GM and WM volumes were found to decrease significantly with age with no age by sex interaction. Overall, these data suggest that the same degree of cognitive impairment is associated with greater structural damage in men compared with women.

A randomized trial on the efficacy of methylphenidate and modafinil for improving cognitive functioning and symptoms in patients with a primary brain tumor

Limited research is available regarding the efficacy of psychostimulants in treating cognitive function in primary brain tumor patients. An open-label, randomized, pilot trial examined both the general and differential efficacy of 4 weeks of methylphenidate (MPH) and modafinil (MOD) in 24 brain tumor patients. Participants completed cognitive tests and self-report measures of fatigue, sleep disturbance, mood and quality of life at baseline and after 4 weeks.Following stimulant treatment, there was evidence of a beneficial effect on test performance in speed of processing and executive function requiring divided attention. Patients with the greatest deficit in executive function at baseline appeared to derive the greatest benefit following stimulant therapy. Inconsistent, differential effects were found on a measure of attention in favor of MPH and on a measure of processing speed in favor of MOD. There was also evidence of a general beneficial effect on patient-reported measures of fatigue, mood, and quality of life, with no statistically significant differences between treatment arms in these measures over time. The results from this small pilot study should be interpreted with caution, but appear to warrant additional research, in larger study samples, targeting fatigue, processing speed and executive function, and exploring different doses of stimulants. Future studies may also wish to explore the specific patient factors that may be associated with responsiveness to psychostimulant treatment.

Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry

Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency.

Controlling tuberculosis in a llama (Lama glama) herd using clinical signs, tuberculin skin testing and serology

An outbreak of tuberculosis (TB), caused by Mycobacterium bovis, was investigated in a small herd of llamas (Lama glama). Based on three ante-mortem diagnostic methods (clinical signs, tuberculin skin test reactions, and 'Rapid Test' serology), 12 llamas were selected for examination post-mortem. Grossly visible lesions suspicious of TB were observed in eight animals, four of which had exhibited clinical signs, one was a skin test 'reactor', and three had been seropositive. M. bovis was isolated from seven of these eight animals. Clinical signs combined with serology were found to be useful in identifying infected animals, but tuberculin skin testing had limited negative predictive value as four llamas that were subsequently confirmed as infected were not detected using this assay.

Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

Sternal stress fracture in a gymnast: A case report and literature review

No Abstract.

Safety and efficacy of treatment using interleukin-2 in a patient with idiopathic CD4(+) lymphopenia and Mycobacterium avium-intracellulare

We present the case of a 39-year-old white man with a Myobacterium avium-intracellulare pulmonary infection found to have a CD4(+) count of 172 cells/mm(3) and diagnosed subsequently with idiopathic CD4(+) lymphopenia (ICL). After receiving clathromycin for 4 months with minimal improvement, the patient was started on pegylated subcutaneous interleukin (IL)-2 at 600,000 units daily. Later, he received incrementally higher pegylated IL-2 doses until he reached a maintenance dose 3 months later of 11 million units weekly divided into three equal doses. After 5 months of therapy, the patient's chronic cough resolved completely, sputum cultures became negative for Myobacterium avium-intracellulare and the CD4(+) T cell count increased to 553 cells/mm(3). After 35 months of well-tolerated IL-2 treatments and no recurrence of any opportunistic infections, IL-2 treatment was stopped. CD4(+) counts 6 and 9 months after discontinuing IL-2 treatment were 596 and 378 cells/mm(3) respectively, and he remains asymptomatic. This report supports IL-2 treatment for ICL-associated opportunistic infections as a safe and potentially efficacious treatment option, especially when combined with more traditional treatment regimens.

Does a dedicated nurse practitioner improve thromboprophylaxis use in acutely ill medical patients in Australia? The methodology for a multicentre VTE Task Force Audit

AIM

To determine the extent to which a multifaceted venous thromboembolism (VTE) prophylaxis program, coordinated by a dedicated nurse practitioner, improves the level of appropriate prophylaxis in patients hospitalised with an acute medical illness.

METHODS

A multicentre clinical audit was conducted in 16 hospitals across Australia. Approximately 9600 acutely ill medical patients over 18 years of age hospitalised for at least 3 days. A 4-month programme implemented by a VTE Nurse Educator to raise awareness of the risk of VTE, the importance of risk assessment and the appropriate prophylactic management of high-risk medical patients with local VTE prophylaxis audit result feedback.

RESULTS

The effect of this programme on the proportion of high-risk medical patients receiving appropriate thromboprophylaxis according to current guidelines.

CONCLUSIONS

The VTE Task Force Audit will be the first multicentre clinical audit in Australia to evaluate thromboprophylaxis use in acutely ill medical patients and the effects of employing a nurse educator. Based on published results from clinical audits conducted overseas, it is expected that thromboprophylaxis will be underutilised in these patients. It is hypothesised that an active multifaceted programme will improve the rate of thromboprophylaxis among eligible medical patients through the effective implementation of evidence-based guidelines.

Skewed X inactivation is associated with phenotype in a female with adrenal hypoplasia congenita

Adrenal hypoplasia congenita (AHC) can occur due to deletions or mutations in the DAX 1 (NR0B1) gene on the X chromosome (OMIM 300200). This form of AHC is therefore predominantly seen in boys. Deletion of the DAX 1 gene can also be part of a larger contiguous deletion including the centromeric dystrophin and glycerol kinase (GK) genes. We report a girl with a de novo deletion at Xp21.2 on the maternal chromosome, including DAX1, the GK gene and 3′ end of the dystrophin gene, who presented with salt losing adrenal insufficiency and moderate developmental delay, but relatively mild features of muscular dystrophy. Investigation using the androgen receptor as a marker gene identified skewed inactivation of the X chromosome. In the patient’s leucocytes, the paternal X chromosome was completely inactive, but in muscle 20% of the active chromosomes were of paternal origin. Thus skewed X inactivation (deletion on the active maternal X chromosome with an inactive paternal X chromosome) is associated with AHC in a female. Variability in X inactivation between tissues may account for the pronounced salt loss and adrenal insufficiency but mild muscular dystrophy.

SLCO1B1 variants and statin-induced myopathy--a genomewide study

BACKGROUND

Lowering low-density lipoprotein cholesterol with statin therapy results in substantial reductions in cardiovascular events, and larger reductions in cholesterol may produce larger benefits. In rare cases, myopathy occurs in association with statin therapy, especially when the statins are administered at higher doses and with certain other medications.

METHODS

We carried out a genomewide association study using approximately 300,000 markers (and additional fine-mapping) in 85 subjects with definite or incipient myopathy and 90 controls, all of whom were taking 80 mg of simvastatin daily as part of a trial involving 12,000 participants. Replication was tested in a trial of 40 mg of simvastatin daily involving 20,000 participants.

RESULTS

The genomewide scan yielded a single strong association of myopathy with the rs4363657 single-nucleotide polymorphism (SNP) located within SLCO1B1 on chromosome 12 (P=4x10(-9)). SLCO1B1 encodes the organic anion-transporting polypeptide OATP1B1, which has been shown to regulate the hepatic uptake of statins. The noncoding rs4363657 SNP was in nearly complete linkage disequilibrium with the nonsynonymous rs4149056 SNP (r(2)=0.97), which has been linked to statin metabolism. The prevalence of the rs4149056 C allele in the population was 15%. The odds ratio for myopathy was 4.5 (95% confidence interval [CI], 2.6 to 7.7) per copy of the C allele, and 16.9 (95% CI, 4.7 to 61.1) in CC as compared with TT homozygotes. More than 60% of these myopathy cases could be attributed to the C variant. The association of rs4149056 with myopathy was replicated in the trial of 40 mg of simvastatin daily, which also showed an association between rs4149056 and the cholesterol-lowering effects of simvastatin. No SNPs in any other region were clearly associated with myopathy.

CONCLUSIONS

We have identified common variants in SLCO1B1 that are strongly associated with an increased risk of statin-induced myopathy. Genotyping these variants may help to achieve the benefits of statin therapy more safely and effectively. (Current Controlled Trials number, ISRCTN74348595.)

Computational model of airflow in upper 17 generations of human respiratory tract

Computational fluid dynamics (CFD) studies of airflow in a digital reference model of the 17-generation airway (bronchial tree) were accomplished using the FLUENT computational code, based on the anatomical model by Schmidt et al. [2004. A digital reference model of the human bronchial tree. Computerized Medical Imaging and Graphics 28, 203-211]. The lung model consists of 6.744 x 10(6) unstructured tetrahedral computational cells. A steady-state airflow rate of 28.3L/min was used to simulate the transient turbulent flow regime using a large eddy simulation (LES) turbulence model. This CFD mesh represents the anatomically realistic asymmetrical branching pattern of the larger airways. It is demonstrated that the nature of the secondary vortical flows, which develop in such asymmetric airways, varies with the specific anatomical characteristics of the branching conduits.

Homocysteine-lowering trials for prevention of vascular disease: protocol for a collaborative meta-analysis

BACKGROUND

Elevated plasma total homocysteine is a risk factor for cardiovascular disease (CVD), but the randomized trials of dietary supplementation with B-vitamins to lower homocysteine have not yet provided clear evidence of benefit on vascular risk.

METHODS

Cumulative meta-analysis of all randomized trials assessing the effects of lowering homocysteine levels with B-vitamins on risk of CVD.

RESULTS

An individual patient data meta-analysis of all randomized trials of the effects on vascular risk of lowering homocysteine with B-vitamins will maximize the power to assess the epidemiologically predicted differences in risk. Among the 12 randomized homocysteine-lowering trials for prevention of CVD, involving more than 1000 participants, data should be available on approximately 52,000 participants (32,000 with prior CVD in unfortified populations; and 14,000 with prior CVD and 6000 with renal disease in fortified populations). To minimize bias, the design and primary analyses to be carried out have been pre-specified. The analyses will include assessment of effects on major vascular events (MVE), stroke, major coronary events (MCE), in addition to venous thrombosis, cancer and fractures. Additional analyses will assess effects on vascular outcomes in sub-groups defined by population, prior disease, per 3 micromol/L difference in homocysteine levels achieved by treatment, pre-treatment vitamin status, duration, age, sex and vascular events excluding revascularizations and, separately, excluding vascular events occurring during the first year of treatment.

CONCLUSIONS

A cumulative meta-analysis of the homocysteine-lowering trials should ensure that reliable evidence emerges about the effects of lowering homocysteine on risk of vascular and non-vascular outcomes.