Coupled coarse graining and Markov Chain Monte Carlo for lattice systems

We propose an efficient Markov Chain Monte Carlo method for sampling equilibrium distributions for stochastic lattice models, capable of handling correctly long and short-range particle interactions. The proposed method is a Metropolis-type algorithm with the proposal probability transition matrix based on the coarse-grained approximating measures introduced in a series of works of M. Katsoulakis, A. Majda, D. Vlachos and P. Plechac, L. Rey-Bellet and D.Tsagkarogiannis,. We prove that the proposed algorithm reduces the computational cost due to energy differences and has comparable mixing properties with the classical microscopic Metropolis algorithm, controlled by the level of coarsening and reconstruction procedure. The properties and effectiveness of the algorithm are demonstrated with an exactly solvable example of a one dimensional Ising-type model, comparing efficiency of the single spin-flip Metropolis dynamics and the proposed coupled Metropolis algorithm.Comment: 20 pages, 4 figure

Effect of fenugreek (Trigonella foenum-graecum L.) intake on glycemia: A meta-analysis of clinical trials

10.1186/1475-2891-13-7Nutrition Journal131

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Cost-effectiveness of viral load testing for transitioning antiretroviral therapy-experienced children to dolutegravir in South Africa: a modelling analysis

Background: For children with HIV on antiretroviral therapy (ART), transitioning to dolutegravir-containing regimens is recommended. The aim of this study was to assess whether introducing viral load testing to inform new nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs) for children with HIV and viraemia alongside dolutegravir-based ART is beneficial and of good economic value. / Methods: We used the Cost-Effectiveness of Preventing AIDS Complications-Pediatric model to project clinical and cost implications of three strategies among a simulated cohort of South African children aged 8 years with HIV receiving abacavir–lamivudine–efavirenz: (1) continue current ART (no dolutegravir; abacavir–lamivudine–efavirenz); (2) transition all children with HIV to dolutegravir, keeping current NRTIs (dolutegravir; abacavir–lamivudine–dolutegravir); or (3) transition to dolutegravir based on viral load testing (viral load plus dolutegravir), keeping current NRTIs if virologically suppressed (abacavir–lamivudine–dolutegravir, 70% of cohort) or switching abacavir to zidovudine (zidovudine) if viraemic (zidovudine–lamivudine–dolutegravir, 30%). We assumed 50% of children who had viraemia after abacavir–lamivudine exposure had NRTI resistance; with resistance, we assumed zidovudine–lamivudine–dolutegravir was more effective than abacavir–lamivudine–dolutegravir. We designated a strategy as preferred if it was most effective and least costly or had an incremental cost-effectiveness ratio less than half the South African 2020 gross domestic product per capita. / Findings: Under base-case assumptions, the viral load plus dolutegravir strategy would be the most effective (projected undiscounted life expectancy of 39·72 life-years) and least costly strategy (US$24 600 per person); the no dolutegravir strategy was the least effective (34·49 life-years) and most expensive ($26 480 per person). In sensitivity analyses, the 24-week virological suppression probability and subsequent monthly virological failure risks (ie, late failure) were most influential on cost-effectiveness. Only with a high late-failure risk for zidovudine–lamivudine–dolutegravir (ie, ≥0·3% per month in the base case or >0·5% per month if abacavir also confers low virological suppression probability in the presence of NRTI resistance [65%]) would the dolutegravir strategy become preferred above the viral load plus dolutegravir strategy. / Interpretation: For programmes transitioning to dolutegravir-based regimens, our model predicted that doing so would be more effective and less costly than continuing current ART regimens, regardless of NRTI choice. Whether viral load testing for children with HIV is necessary to inform NRTI choice depends substantially on the comparative outcomes of abacavir and zidovudine after switching to dolutegravir-containing ART. / Funding: The Eunice Kennedy Shriver Institute for Child Health and Human Development, the National Institute of Allergy and Infectious Diseases, the Massachusetts General Hospital Executive Committee on Research, the Massachusetts General Hospital, and the Medical Research Council

Antihyperlipidemic effects of Pleurotus ostreatus (oyster mushrooms) in HIV-infected individuals taking antiretroviral therapy

<p>Abstract</p> <p>Background</p> <p>Antiretroviral treatment (ART) regimens in HIV patients commonly cause significant lipid elevations, including increases in both triglycerides and cholesterol. Standard treatments for hypercholesterolemia include the HMG CoA reductase inhibitors, or "statins." Because many ART agents and statins share a common metabolic pathway that uses the cytochrome P450 enzyme system, coadministration of ART with statins could increase statin plasma levels significantly. The oyster mushroom, <it>Pleurotus ostreatus</it>, has been shown in animal models to decrease lipid levels - a finding that has been supported by preliminary data in a small human trial.</p> <p>Methods</p> <p>To assess the safety and efficacy of <it>P. ostreatus </it>in patients with HIV and ART-induced hyperlipidemia, a single-arm, open-label, proof-of-concept study of 8 weeks' duration with a target enrollment of 20 subjects was conducted. Study patients with ART-induced elevated non-HDL cholesterol levels (> 160 mg/dL) were enrolled. Participants received packets of freeze-dried <it>P. ostreatus </it>(15 gm/day) to be administered orally for the 8 week trial period. Lipid levels were drawn every two weeks to assess efficacy. Safety assessments included self-reported incidence of muscle aches and measurement of liver and muscle enzymes. Mean within-person change in lipid levels were estimated using generalized estimating equations to account for repeated observations on individuals. A 30 mg/dL decrease in non-HDL cholesterol was deemed clinically significant.</p> <p>Results</p> <p>126 patients were screened to enroll 25, of which 20 completed the 8-week study. The mean age was 46.4 years (36-60). Patients had a mean 13.7 yrs of HIV infection. Mean non-HDL cholesterol was 204.5 mg/dL at day 0 and 200.2 mg/dL at day 56 (mean within-person change = -1.70; 95% confidence interval (CI) = -17.4, 14.0). HDL cholesterol levels increased from 37.8 mg/dL at day 0 to 40.4 mg/dL on day 56 (mean within-person change = 2.6; 95% CI = -0.1, 5.2). Triglycerides dropped from 336.4 mg/dL on day 0 to 273.4 mg/dL on day 56 (mean within-person change = -63.0; 95% CI = -120.9, -5.1). Only 3 individuals achieved a sustained clinically significant (30 mg/dL) decline in non-HDL cholesterol after 8 weeks of therapy. There were no adverse experiences reported other than patients' distaste for the preparation. Liver function tests and muscle enzymes were not affected by the 8 weeks of treatment.</p> <p>Conclusions</p> <p><it>Pleurotus ostreatus </it>as administered in this experiment did not lower non-HDL cholesterol in HIV patients with ART-induced hypercholesterolemia. Small changes in HDL and triglycerides were not of a clinical magnitude to warrant further study.</p> <p>Trial Registration</p> <p>clinicaltrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00069524">NCT00069524</a></p

Cord blood calcium, phosphate, magnesium, and alkaline phosphatase gestational age-specific reference intervals for preterm infants

<p>Abstract</p> <p>Background</p> <p>The objective was to determine the influence of gestational age, maternal, and neonatal variables on reference intervals for cord blood bone minerals (calcium, phosphate, magnesium) and related laboratory tests (alkaline phosphatase, and albumin-adjusted calcium), and to develop gestational age specific reference intervals based on infants without influential pathological conditions.</p> <p>Methods</p> <p>Cross-sectional study. 702 babies were identified as candidates for this study in a regional referral neonatal unit. After exclusions (for anomalies, asphyxia, maternal magnesium sulfate administration, and death), relationships were examined between cord blood serum laboratory analytes (calcium, phosphate, magnesium, alkaline phosphatase, and albumin-adjusted calcium) with gestation age and also with maternal and neonatal variables using multiple linear regression. Infants with influential pathological conditions were omitted from the development of gestational age specific reference intervals for the following categories: 23-27, 28-31, 32-34, 35-36 and > 36 weeks.</p> <p>Results</p> <p>Among the 506 preterm and 54 terms infants included in the sample. Phosphate, magnesium, and alkaline phosphatase in cord blood serum decreased with gestational age, calcium increased with gestational age. Those who were triplets, small for gestational age, and those whose mother had pregnancy-induced hypertension were influential for most of the analytes. The reference ranges for the preterm infants ≥ 36 weeks were: phosphate 1.5 to 2.6 mmol/L (4.5 to 8.0 mg/dL), calcium: 2.1 to 3.1 mmol/L (8.3 to 12.4 mg/dL); albumin-adjusted calcium: 2.3 to 3.2 mmol/L (9.1 to 12.9 mg/dL); magnesium 0.6 to 1.0 mmol/L (1.4 to 2.3 mg/dL), and alkaline phosphatase 60 to 301 units/L.</p> <p>Conclusions</p> <p>These data suggest that gestational age, as well as potentially pathogenic maternal and neonatal variables should be considered in the development of reference intervals for preterm infants.</p

Continuum Molecular Simulation of Large Conformational Changes during Ion–Channel Gating

A modeling framework was developed to simulate large and gradual conformational changes within a macromolecule (protein) when its low amplitude high frequency vibrations are not concerned. Governing equations were derived as alternative to Langevin and Smoluchowski equations and used to simulate gating conformational changes of the Kv7.1 ion-channel over the time scale of its gating process (tens of milliseconds). The alternative equations predict the statistical properties of the motion trajectories with good accuracy and do not require the force field to be constant over the diffusion length, as assumed in Langevin equation. The open probability of the ion–channel was determined considering cooperativity of four subunits and solving their concerted transition to the open state analytically. The simulated open probabilities for a series of voltage clamp tests produced current traces that were similar to experimentally recorded currents