Imitation of β-lactam binding enables broad-spectrum metallo-β-lactamase inhibitors

Carbapenems are vital antibiotics, but their efficacy is increasingly compromised by metallo-beta-lactamases (MBLs). Here we report the discovery and optimization of potent broad-spectrum MBL inhibitors. A high-throughput screen for NDM-1 inhibitors identified indole-2-carboxylates (InCs) as potential beta-lactamase stable beta-lactam mimics. Subsequent structure-activity relationship studies revealed InCs as a new class of potent MBL inhibitor, active against all MBL classes of major clinical relevance. Crystallographic studies revealed a binding mode of the InCs to MBLs that, in some regards, mimics that predicted for intact carbapenems, including with respect to maintenance of the Zn(II)-bound hydroxyl, and in other regards mimics binding observed in MBL-carbapenem product complexes. InCs restore carbapenem activity against multiple drug-resistant Gram-negative bacteria and have a low frequency of resistance. InCs also have a good in vivo safety profile, and when combined with meropenem show a strong in vivo efficacy in peritonitis and thigh mouse infection models.Peer reviewe

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Distributed Model-based Predictive Secondary Control for Hybrid AC/DC Microgrids

This paper presents a novel scheme based on distributed model-based predictive control for the secondary level control of hybrid AC/DC microgrids. Prediction models based on droop control and power transfer equations are proposed to characterize the generators in both the AC and DC sub-microgrids, whereas power balance constraints are used to predict the behavior of interlinking converters. The operational constraints (such as powers and control action limits) are included in all the formulations. Experimental results validate the proposed scheme for the following cases: (i) load changes, working within operating constraints, (ii) managing frequency regulation in the AC sub-microgrid, voltage regulation in the DC sub-microgrid and global power consensus in the whole hybrid microgrid, and (iii) maintaining the microgrid performance in the presence of communication malfunction while ensuring that plug-and-play capability is preserved

Relative methylated arginine release over 5 h from PRBC incubation.

<p>All three methylated arginines, ADMA, LNMMA, and symmetric dimethylarginine were released in proportionately similar amounts during the 5h incubation at 37°C. The starting free concentrations were different (0.58 ± 0.12, 0.08 ± 0.02, and 0.20 ± 0.12 respectively). Free ADMA, LNMMA and symmetric dimethylarginine increased significantly from baseline by 5h. Linear regression analysis failed to detect differences among methylated arginines over 5h.</p

Incubation-induced release of Free ADMA over 5h by Blood Product type.

<p>Incubation of defrosted fresh frozen plasma (open triangles), supernatants of PRBC alone (solid squares), a mixture of 1:1 PRBC and fresh frozen plasma (open circles), and a mixture of 1:3 PRBC and fresh frozen plasma (open diamonds). Repeated measures Two-way ANOVA shows significant differences of ADMA among PRBC and PRBC: fresh frozen plasma groups over the incubation period (p<0.006). Tukey’s <i>post-hoc</i> multiple comparison test revealed significant differences of ADMA (α = 0.05) among groups at individual sampling points. At three and five hour time points, ADMA in PRBC and 1:1 PRBC: fresh frozen plasma was significantly (*) higher than 1:3 PRBC: fresh frozen plasma. Hemoglobin measurements confirmed PRBC concentration and dilutions.</p

Hematologic values for PRBCs in Catalase experiment.

<p>*The average value for μmol ADMA/ g catalase was determined separately on pure human catalase following strong acid hydrolysis. This value was multiplied by the measured catalase concentration in g/L PRBC to give the estimated μmol ADMA/L of PRBC.</p><p>Hematologic values for PRBCs in Catalase experiment.</p

Arginine and its endogenous methylated derivatives.

<p>Arginine is the normal substrate for NOS resulting in NO formation. A single methylation of arginine produces monomethylarginine (LNMMA) which, along with asymmetric dimethylarginine (ADMA), are endogenous inhibitors of NOS. ADMA and LNMMA are hydrolyzed by dimethylarginine dimethylaminohydrolase (DDAH). Symmetric dimethylarginine does not inhibit NOS. These structures were drawn as they exist at mammalian physiological pH using ChemDraw software (PerkinElmer Informatics) and data from PubChem at NCBI at the National Library of Medicine (USA).</p

Total methylarginines obtained by strong acid hydrolysis of pre-aliquoted PRBCs stored at 6°C or -80°C.

<p>No statistically significant differences were detected between 6°C or -80°C storage at any time (pooled to 5, 14, 28 and 42 d) for ADMA, LNMMA and symmetric dimethylarginine and no change from control was detected. It is likely that neither PRMT activity nor DDAH-induced hydrolysis was a dominating effect under these storage conditions. However, equal formation and hydrolysis cannot be ruled out.</p

ADMA scaled against hemoglobin concentration over storage time at 6°C or -80°C.

<p>In an attempt to account for any dehydration of the samples under either storage condition (6°C or -80°C), we measured hemoglobin concentrations paired with each ADMA measurement to calculate ADMA to hemoglobin ratio. The time course and pattern remained unchanged over time suggesting no measurable desiccation effect on sample concentration over the 42-day storage.</p