Evolving ω-amine transaminase AtATA guided by substrate-enzyme binding free energy for enhancing activity and stability against non-natural substrates.

In the field of chiral amine synthesis, ω-amine transaminase (ω-ATA) is one of the most established enzymes capable of asymmetric amination under optimal conditions. However, the applicability of ω-ATA toward more non-natural complex molecules remains limited due to its low transamination activity, thermostability, and narrow substrate scope. Here, by employing a combined approach of computational virtual screening strategy and combinatorial active-site saturation test/iterative saturation mutagenesis strategy, we have constructed the best variant M14C3-V5 (M14C3-V62A-V116S-E117I-L118I-V147F) with improved ω-ATA from Aspergillus terreus (AtATA) activity and thermostability toward non-natural substrate 1-acetylnaphthalene, which is the ketone precursor for producing the intermediate (R)-(+)-1-(1-naphthyl)ethylamine [(R)-NEA] of cinacalcet hydrochloride, showing activity enhancement of up to 3.4-fold compared to parent enzyme M14C3 (AtATA-F115L-M150C-H210N-M280C-V149A-L182F-L187F). The computational tools YASARA, Discovery Studio, Amber, and FoldX were applied for predicting mutation hotspots based on substrate-enzyme binding free energies and to show the possible mechanism with features related to AtATA structure, catalytic activity, and stability in silico analyses. M14C3-V5 achieved 71.8% conversion toward 50 mM 1-acetylnaphthalene in a 50 mL preparative-scale reaction for preparing (R)-NEA. Moreover, M14C3-V5 expanded the substrate scope toward aromatic ketone compounds. The generated virtual screening strategy based on the changes in binding free energies has successfully predicted the AtATA activity toward 1-acetylnaphthalene and related substrates. Together with experimental data, these approaches can serve as a gateway to explore desirable performances, expand enzyme-substrate scope, and accelerate biocatalysis.IMPORTANCEChiral amine is a crucial compound with many valuable applications. Their asymmetric synthesis employing ω-amine transaminases (ω-ATAs) is considered an attractive method. However, most ω-ATAs exhibit low activity and stability toward various non-natural substrates, which limits their industrial application. In this work, protein engineering strategy and computer-aided design are performed to evolve the activity and stability of ω-ATA from Aspergillus terreus toward non-natural substrates. After five rounds of mutations, the best variant, M14C3-V5, is obtained, showing better catalytic efficiency toward 1-acetylnaphthalene and higher thermostability than the original enzyme, M14C3. The robust combinational variant acquired displayed significant application value for pushing the asymmetric synthesis of aromatic chiral amines to a higher level.

The predictive value of cumulative atherogenic index of plasma (AIP) for cardiovascular outcomes: a prospective community-based cohort study.

BACKGROUND: Atherogenic index of plasma (AIP) has been reported as a critical predictor on the risks and clinical outcomes of cardiovascular diseases (CVDs), and we aimed to explore the potential predictive value of cumulative AIP on major adverse cardiac events (MACE), stroke, myocardial infarction (MI) and cardiovascular mortality. METHODS: A large-scale community-based prospective cohort was established from December 2011 to April 2012 and followed up in May to July 2014. The endpoint outcomes were obtained before December 31, 2021. AIP was calculated as the logarithmically transformed ratio of triglyceride (TG) to high-density lipoprotein cholesterol (HDL-c) and cumulative AIP was the average value of AIP in 2012 and 2014. RESULTS: An overall of 3820 participants (36.1% male) with mean (SD) age of 59.1 (8.7) years, were enrolled. Within a median follow-up of 7.5 years, a total of 371 (9.7%) participants were documented with MACE, 293 (7.7%) participants developed stroke, 68 (1.8%) suffered from MI and 65 (1.7%) experienced cardiovascular mortality. Multivariable Cox regression analysis revealed significant associations between cumulative AIP and the risk of MACE, stroke and MI. Regarding MACE, individuals with one higher unit of cumulative AIP were associated with 75% increment on the incidence of going through MACE in fully adjusted model, while categorizing participants into four groups, individuals in the highest cumulative AIP quartile were significantly associated with increased incidence of MACE (HR = 1.76, 95%CI: 1.27-2.44, p < 0.001 in fully adjusted model), stroke (HR = 1.69, 95%CI: 1.17-2.45, p = 0.005) and MI (HR = 2.82, 95%CI: 1.18-6.72, p = 0.019). But not a significant association was observed between cumulative AIP and cardiovascular mortality. In subgroup analysis, the association of cumulative AIP and the incidence of stroke was more pronounced in the elderly (HR: 0.89 vs. 2.41 for the age groups < 65 years and ≥ 65 years, p for interaction = 0.018). CONCLUSIONS: A higher cumulative AIP was significantly associated with an increased risk of MACE, stroke and MI independent of traditional cardiovascular risk factors in a community-based population, and the association of cumulative AIP and stroke was particularly pronounced in the elderly population.

Randomized trial comparing the effects of a 3D head-up system and microscope eyepiece-assisted simulated vitrectomy with intraocular illumination on the ocular surface of an operator.

BACKGROUND: To compare the effects of a 3D head-up system and microscope eyepiece-assisted simulated vitrectomy intraocular illumination on the ocular surface of an operator. METHODS: This was a prospective randomized controlled study. According to the application system, thirty ophthalmic operators (60 eyes) were randomly divided into 3D and eyepiece groups. Under different intensities of intraocular illumination, operators in both groups viewed the fundus model through a 3D display screen or microscopic eyepiece for 2 h. Objective examinations and a subjective symptom questionnaire were used immediately after the test to evaluate the ocular surface of the operators. Objective examinations included nonintrusion tear meniscus height (NIKTMH), nonintrusion break-up time (NIKBUT), and bulbar redness and strip meniscometry tube (SMTube) measurements. Statistical analyses were performed by using SPSS 26.0 software. RESULTS: After the test, the NIKTMH, NIKBUT and SMTube measurements decreased; however, the degree of change varied among the groups of different systems. The differences between the 3D group and the eyepiece group in NIKTMH measurements, SMTube measurements, subjective symptom scores (eye dryness, difficulty focusing, and cervical pain), and light intensity reaching the ocular surface of the operators were statistically significant (P < 0.05). All of the objective and subjective tests showed that the 3D group had fewer effects on the NIKTMH and SMTube measurements, and the subjective comfort of the 3D group was greater. CONCLUSION: For both 3D screens and eyepieces, simulated vitrectomy with intraocular illumination for two hours can lead to discomfort and abnormalities in the operator's ocular surface; however, these abnormalities are less severe in the 3D group. TRIAL REGISTRATION: This trial was registered on December 22, 2022, at the Chinese Clinical Trials Registry with NO. ChiCTR2200066989.

Genetic association analysis of dietary intake and idiopathic pulmonary fibrosis: a two-sample mendelian randomization study.

BACKGROUND: IPF is a complex lung disease whose aetiology is not fully understood, but diet may have an impact on its development and progression. Therefore, we investigated the potential causal connection between dietary intake and IPF through TSMR to offer insights for early disease prevention recommendations. METHODS: The study incorporated 29 dietary exposure factors, oily fish intake, bacon intake, processed meat intake, poultry intake, beef intake, pork intake, lamb/mutton intake, non-oily fish intake, fresh fruit intake, cooked vegetable intake, baked bean intake, fresh tomato intake, tinned tomato intake, salad/raw vegetable intake, Fresh fruit intake, coffee intake, tea intake, water intake, red wine intake, average weekly beer plus cider intake, alcoholic drinks per week, cereal intake, bread intake, whole-wheat intake, whole-wheat cereal intake, cheese intake, yogurt intake, salt added to food and whole egg intake. The study explored the causal link between diet and IPF using TSMR analysis, predominantly the IVW method, and performed sensitivity analyses to validate the results. RESULT: The study revealed that consuming oily fish, yogurt, and dried fruits had a protective effect against IPF, whereas the consumption of alcoholic beverages and beef was linked to an increased risk of IPF. CONCLUSION: In this MR study, it was discovered that the consumption of oily fish, yogurt, and dried fruits exhibited a protective effect against IPF, whereas the intake of alcoholic beverages and beef was associated with an elevated risk of IPF. These findings underscore the significance of making informed and timely dietary decisions in IPF prevention.

Isolation and protein MdtQ analysis of outer membrane vesicles released by carbapenem-resistant Klebsiella pneumoniae.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a leading public health problem, and is increasingly being reported worldwide with resistance to a wide spectrum of antibiotics. Recent reports have demonstrated that the outer membrane vesicles (OMVs) of gram-negative bacteria are potent resistance factors, but their role in the drug resistance of CRKP has not been elucidated. In order to investigate the effects of OMV components on drug resistance and to explore the mechanism of antimicrobial resistance in CRKP, we isolated the OMVs through ultracentrifugation, separated the OMV proteins through mass spectrometry (MS), and performed bioinformatics analysis. A total of 3,192 proteins were detected by nano LC-MS/MS analysis, with 108 (61.4%) cytoplasmic proteins, 50 (28.4%) cytoplasmic membrane proteins, nine (5.1%) periplasmic proteins, six (3.4%) outer membrane proteins, two (1.1%) extracellular proteins, and one (0.6%) other protein detected in the vesicles. MdtQ was detected as the only multidrug resistance outer membrane protein. Further experiments confirmed that MdtQ included the 1440 BP sequence and had a unique three-dimensional structure. To superimpose MdtQ with KPC-2 resistant proteins, I7ACB1, I7AKP2, and Q93LQ9, the root mean square deviation (RMSD) values were calculated (0.379, 0.671, and 1.35, respectively). I7ACB1 had the lowest RMSD value, indicating that it had the best superimposition effect. Furthermore, MdtQ had 20 biological pocket structures, and the four most important pockets were evenly distributed around the inner perimeter of its three-dimensional structure. These findings may provide a theoretical basis for controlling the spread of bacterial resistance in the future.

Static Binding and Dynamic Transporting-Based Design of Specific Ring-Chain-Ring Acetylcholinesterase Inhibitor: From Galantamine to Natural Product.

Acetylcholinesterase (AChE) is a key target for the current symptomatic treatment of Alzheimer's disease, and galantamine is a clinical anticholinesterase drug with transiently acting characteristic and good selectivity for AChE. The present theoretical-experimental work improves the drug's residence time without reducing the inhibition effect, thus providing a crucial breakthrough for modifying the inhibitor of AChE with better kinetic behavior. The static binding and dynamic delivery properties acquired from atomic view reveal that the galantamine simply occupies a catalytic anionic site, and its release from AChE needs only ∼8.6 kcal/mol. Both of these may cause the short residence time of galantamine. The hotspots and most favorable transport mechanism are identified, and the hydrogen bond and aromatic stacking interactions are observed to play crucial roles for galantamine binding and release in AChE. The typical peripheral anionic site arisen at the delivery process would provide another key occupation to enhance the anti-release ability for inhibitors. The compound with "specific-ring-chain-ring" framework with detailed beneficial modification scheme is summarized, which may improve the residence time of the inhibitor in AChE. The thermodynamic and dynamic properties of galantamine derivatives are also studied. Based on dictamnine, a natural alkaloid, two novel eligible derivatives are designed, synthesized and evaluated, which verifies our prediction. Multiple computational approaches and experimental combinations probably provide a train of thought from both static and dynamic views to modify or design appropriate inhibitors on the basis of specific binding and transportation features.

Survival of community-acquired Bacillus cereus sepsis with venous sinus thrombosis in an immunocompetent adult man - a case report and literature review.

BACKGROUND: Bacillus cereus infections in immunocompetent patients are uncommon and mainly observed in fragile patients. It can cause lethal infections with multiple organ dysfunction syndrome (MODS). However, a patient presenting as venous sinus thrombosis and survival without sequela has not been reported. CASE PRESENTATION: A 20-year-old previously healthy male developed gastroenteritis after a meal, followed by fever, convulsions, and severe disturbance of consciousness. The patient had significant leukocytosis with a mildly elevated D-dimer, creatinine level, and respiratory failure. The CT(computed tomography) revealed fatal brain edema and subarachnoid hemorrhage. Previous blood culture in a local hospital revealed B. cereus, which was confirmed by mNGS(metagenomic next-generation sequencing) using blood and urine in our hospital. Accordingly, B. cereus sepsis with MODS were considered. Later, cerebral venous sinus thrombosis was proved. After anti-infection (linezolid 0.6 g, Q12h; and meropenem 1.0 g, Q8h), anti-coagulant (enoxaparin 6000U, Q12h), and other symptomatic treatments, the patient recovered completely without sequela at the 6-month follow-up. CONCLUSIONS: This case suggests that in immunocompetent adults, there is still a risk of infection with B. cereus, causing severe MODS. Special attention should be paid to venous sinus thrombosis and subarachnoid hemorrhage in such cases, while, anti-coagulant is essential therapy.

Atomistic insight into the binding mode and self-regulation mechanism of IsPETase towards PET substrates with different polymerization degrees.

Poly(ethylene terephthalate) (PET) is one of the most widely used synthetic polyesters, however, its extensive use creates a long-term environmental burden. Unlike traditional recycling methods, biodegradation is a sustainable strategy. The emergence of PETase from Ideonella sakaiensis 201-F6 (IsPETase) has brought great potential for the industrialization of degradable PET. In this work, models of enzyme-substrate complexes with different degrees of polymerization were established to study the binding mode using molecular dynamics simulation. We found that the whole binding site can be further subdivided into three parts, including head, middle and tail binding regions. Most importantly, the presence of the middle region formed by both ends of Ser93 and Ser236 provides a potential possibility for the binding of substrates with different chain lengths, and exerts the self-regulation ability of enzymes to accommodate substrates. Meanwhile, the 'pocket bottom' Arg280 in the tail region echoes the 'pocket mouth' Trp185 in the head region, defining the substrate binding region. This work reveals the self-regulation of IsPETase, as well as the key residues for the substrate binding. The solution to these problems enables us to better understand the function of enzymes and design high-performance degradation enzymes, which is of great significance for industrial application research.

Additive effect between homocysteine and low-density-lipoprotein cholesterol upon incidence of novel carotid plaque formation: data from a Chinese community-based cohort.

OBJECTIVE: Homocysteine (HCY) has been associated with carotid plaque in cross-sectional studies, but the prospective relationship between HCY and incident carotid plaque has not been well established. The purpose of this study was to investigate the association between HCY and incidence of novel carotid plaque in a Chinese community-based population without pre-existing carotid atherosclerosis and to assess the additive effect of HCY and low-density lipoprotein cholesterol (LDL-C) on the incidence of novel plaque. METHODS: At baseline, we measured HCY and other risk factors in subjects aged ≥ 40 years. All participants underwent carotid ultrasound examinations at baseline and after an average of 6.8 years of follow-up. Incidence of plaque was identified if plaque was absent at baseline, but plaque was detected at the end of follow-up. A total of 474 subjects were included in the analysis. RESULTS: The incidence of novel carotid plaque was 24.47%. Multivariate regression analyses showed that HCY was independently associated with a 1.05-fold-higher likelihood for incident novel plaque (adjusted odds ratio [OR] = 1.05, 95% confidence interval [CI]: 1.01-1.09, P = 0.008). Using tertile 1 and tertile 2 for reference, the top HCY tertile (T3) showed a 2.28-fold-higher likelihood for incident plaque (adjusted OR = 2.28, 95%CI: 1.33-3.93, P = 0.002). The combination of HCY T3 and LDL-C ≥ 3.4 mmol/L had the highest risk for novel plaque formation (adjusted OR = 3.63, 95%CI: 1.67-7.85, P = 0.001) compared to those without either condition. In the LDL-C ≥ 3.4 mmol/L subgroup, HCY was significantly associated with incidence of plaque (adjusted OR = 1.16, 95%CI: 1.04-1.28, P = 0.005, P-interaction = 0.023). CONCLUSION: In the Chinese community-based population, HCY was independently associated with the incidence of novel carotid plaque. There were additive effect between HCY and LDL-C on the incidence of plaque, the highest risk was observed in individuals with both high HCY levels and LDL-C ≥ 3.4 mmol/L. Our findings suggest that HCY may be a potential target for preventing the incidence of carotid plaque, particularly in individuals with elevated LDL-C levels.

[Extraction of Extracelluar Vesicles Derived from Mycobacterium tuberculosis and Their Effect on the Production of Reactive Oxygen Species and Expression of Inflammatory Factors in Mouse Bone Marrow-Derived Dendritic Cells].

Objective: To isolate extracellular vesicles (EVs) from Mycobacterium tuberculosis ( Mtb), to examine their morphology, particle size, and distribution, to study the effect of EVs derived from Mtb ( Mtb-EVs) on intracellular reactive oxygen species (ROS) production and cytokine secretion in dendritic cells (DCs), and to make preliminary exploration of Mtb-EVs' effect on the immune regulation of DCs. Methods: Mtb-EVs were obtained by ultrafiltration concentration and the protein concentration was determined by BCA assay. The morphology of Mtb-EVs was observed through negative staining electron microscopy (EM). The particle size distribution and concentration of Mtb-EVs were determined by nanoparticle tracking analysis (NTA). Mouse bone marrow was isolated through sterile procedures and mice myeloid DCs were induced and amplified by the combined use of recombinant mouse granulocyte-macrophage colony-stimulating factor (rm GM-CSF) and recombinant mouse interleukin-4 (rm IL-4). Then, morphological and immunophenotypic characterization was performed. After that, the DCs were treated with Mtb-EVs at different concentrations and CCK-8 assay was done to measure their effect on the survival rate of DCs and to identify the appropriate stimulation concentration for subsequent experimental procedures. The intracellular ROS levels of DCs were evaluated with DCFH-DA fluorescence probe and the cytokine secretion of DCs was determined by ELISA. Results: EM observation showed that Mtb-EVs isolated by ultrafiltration concentration were spherical vesicles of varied sizes, all being approximately 100 nm in diameter and displaying typical morphology. NTA results from NanoSight nanoparticle tracker showed that the peak particle size was 98.5 nm, that the average particle size was 110.2 nm, and that the particle size was mainly distributed between 68.4-155.7 nm. Mtb-EVs that were smaller than 250 nm accounted for 98.39% of the total. Mouse myeloid DCs directionally induced and amplified in vitro displayed typical DC phenotype and morphology, and the purity exceeded 85%. EM verified the abundance of microvilli and radial protuberance on the surface of DCs, which had uniform cytoplasm and clear nuclear membrane. Loaded with Mtb-EVs at different concentrations, including 10 2, 10 3, and 10 4 particles/cell, the DCs had significantly upregulated levels of intracellular ROS ( P<0.05). In addition, Mtb-EVs induced the release of IL-1ß and IL-6 in a dose-dependent manner ( P<0.05). Conclusion: We established in the study a technical process for the extraction of Mtb-EVs by ultrafiltration concentration and obtained Mtb-EVs with sound morphology, high purity, and concentrated particle size distribution. Furthermore, Mtb-EVs can upregulate the intracellular ROS level in DCs and induce the release of IL-1ß and IL-6 in a dose-dependent manner.

Uncovering the Metabolic Mechanism of Salidroside Alleviating Microglial Hypoxia Inflammation Based on Microfluidic Chip-Mass Spectrometry.

Microglia are the main immune cells in the brain playing a critical role in neuroinflammation, and numerous pieces of evidence have proved that energy metabolism is closely associated with inflammation in activated microglia. Salidroside (Sal) isolated from Tibetan medicine Rhodiola crenulate can inhibit microglial hypoxia inflammation (HI). However, whether the inhibition is due to the intervening energy metabolic process in microglia is not clear. In this work, the hypoxic microenvironment of BV2 microglial cells was simulated using deferoxamine (DFO) in vitro and the change of cell metabolites (lactate, succinate, malate, and fumarate) was real-time online investigated based on a cell microfluidic chip-mass spectrometry (CM-MS) system. Meanwhile, for confirming the metabolic mechanism of BV2 cells under hypoxia, the level of HI-related factors (LDH, ROS, HIF-1α, NF-κB p65, TNF-α, IL-1ß, and IL-6) was detected by molecular biotechnology. Integration of the detected results revealed that DFO-induced BV2 cell HI was associated with the process of energy metabolism, in which cell energy metabolism changed from oxidative phosphorylation to glycolysis. Furthermore, administration of Sal treatment could effectively invert this change, and two metabolites of Sal were identified: tyrosol and 4-hydroxyphenylacetic acid. In general, we illustrated a new mechanism of Sal for reducing BV2 cell HI injury and presented a novel analysis strategy that opened a way for real-time online monitoring of the energy metabolic mechanism of the effect of drugs on cells and further provided a superior strategy to screen natural drug candidates for HI-related brain disease treatment.

Effect of sodium-glucose cotransporter-2 inhibitors on blood pressure in patients with heart failure: a systematic review and meta-analysis.

BACKGROUND: Recent studies have shown that sodium-glucose cotransporter-2 inhibitors (SGLT2i) can achieve significant improvement in blood pressure in people with diabetes. Furthermore, randomized controlled trials (RCTs) have established that SGLT2i have a cardioprotective effect in adults with heart failure (HF). Therefore, we performed this systematic review an meta-analysis to determine the effect of SGLT2i on blood pressure in patients with HF. METHODS: We used the Medline, Cochrane Library, Embase, and PubMed databases to identify RCTs (published through to April 29, 2022) that evaluated the effect of SGLT2i on HF. The primary endpoint was defined as change in blood pressure. Secondary composite outcomes were heart rate, hematocrit, body weight, and glycated hemoglobin. The N-terminal pro-brain natriuretic peptide level, Kansas City Cardiomyopathy Questionnaire scores, and estimated glomerular filtration rate were also evaluated. RESULTS: After a literature search and detailed evaluation, 16 RCTs were included in the quantitative analysis. Pooled analyses showed that SGLT2i were associated with a statistically significant reduction in systolic blood pressure of 1.68 mmHg (95% confidence interval [CI] - 2.7, - 0.66; P = 0.001; I2 = 45%) but not diastolic blood pressure (mean difference [MD] -1.06 mmHg; 95% CI -3.20, 1.08; P = 0.33; I2 = 43%) in comparison with controls. Furthermore, SGLT2i decreased body weight (MD - 1.36 kg, 95% CI - 1.68, - 1.03; P < 0.001; I2 = 61%) and the glycated hemoglobin level (MD - 0.16%, 95% CI - 0.28, -0.04, P = 0.007; I2 = 91%) but increased hematocrit (MD 1.63%, 95% CI 0.63, 2.62, P = 0.001; I2 = 100%). There was no significant between-group difference in heart rate (MD - 0.35; 95% CI - 2.05, 1.35, P = 0.69; I2 = 0). CONCLUSIONS: SGLT2i decreased systolic blood pressure in patients with HF but had no effect on diastolic blood pressure. These inhibitors may have numerous potentially beneficial clinical effects in patients with HF.

Degradation of pesticides diazinon and diazoxon by phosphotriesterase: insight into divergent mechanisms from QM/MM and MD simulations.

Enzymatic hydrolysis by phosphotriesterase (PTE) is one of the most effective ways of degrading organophosphorus pesticides, but the catalytic efficiency depends on the structural features of substrates. Here the enzymatic degradation of diazinon (DIN) and diazoxon (DON), characterized by PS and PO, respectively, have been investigated by QM/MM calculations and MM MD simulations. Our calculations demonstrate that the hydrolysis of DON (with PO) is inevitably initiated by the nucleophilic attack of the bridging-OH- on the phosphorus center, while for DIN (with PS), we proposed a new degradation mechanism, initiated by the nucleophilic attack of the Znα-bound water molecule, for its low-energy pathway. For both DIN and DON, the hydrolytic reaction is predicted to be the rate-limiting step, with energy barriers of 18.5 and 17.7 kcal mol-1, respectively. The transportation of substrates to the active site, the release of the leaving group and the degraded product are generally verified to be favorable by MD simulations via umbrella sampling, both thermodynamically and dynamically. The side-chain residues Phe132, Leu271 and Tyr309 play the gate-switching role to manipulate substrate delivery and product release. In comparison with the DON-enzyme system, the degraded product of DIN is more easily released from the active site. These new findings will contribute to the comprehensive understanding of the enzymatic degradation of toxic organophosphorus compounds by PTE.

QM/MM and MM MD simulations on decontamination of the V-type nerve agent VX by phosphotriesterase: toward a comprehensive understanding of steroselectivity and activity.

Due to deadly toxicity and high environmental stability of the nerve agent VX, an efficient decontamination approach is desperately needed in tackling its severe threat to human security. The enzymatic destruction of nerve agents has been generally considered as one of the most effective ways, and here the hydrolysis of VX by phosphotriesterase (PTE) was investigated by extensive QM/MM and MM MD simulations. The hydrolytic cleavage of P-S by PTE is a two-step process with the free energy spans of 15.8 and 26.0 kcal mol-1 for the RP- and SP-enantiomer VX, respectively, and such remarkable stereospecificity of VX enantiomers in the enzymatic degradation is attributed to their conformational compatibility with the active pocket. The structurally less adaptive SP-enantiomer allows one additional water molecule to enter the binuclear zinc center and remarkably facilitates the release of the degraded product. Overall, the rate-limiting steps in the enzymatic degradation of VX by PTE involve the degraded product release of the RP-enantiomer and the enzymatic P-S cleavage of the SP-enantiomer. Further computational analysis on the mutation of selected residues also revealed that H257Y, H257D, H254Q-H257F, and L7ep-3a variants allow more water molecules to enter the active site, which improves the catalytic efficiency of PTE, as observed experimentally. The present work provides mechanistic insights into the stereoselective hydrolysis of VX by PTE and the activity manipulation through the active-site accessibility of water molecules, which can be used for the enzyme engineering to defeat chemical warfare agents.

Outdoor air pollution and the risk of asthma exacerbations in single lag0 and lag1 exposure patterns: a systematic review and meta-analysis.

Objective: To synthesize evidence regarding the relationship between outdoor air pollution and risk of asthma exacerbations in single lag0 and lag1 exposure patterns.Methods: We performed a systematic literature search using PubMed, Embase, Cochrane Library, Web of Science, ClinicalTrials, China National Knowledge Internet, Chinese BioMedical, and Wanfang databases. Articles published until August 1, 2020 and the reference lists of the relevant articles were reviewed. Two authors independently evaluated the eligible articles and performed structured extraction of the relevant information. Pooled relative risks (RRs) and 95% confidence intervals (CIs) of lag0 and lag1 exposure patterns were estimated using random-effect models.Results: Eighty-four studies met the eligibility criteria and provided sufficient information for meta-analysis. Outdoor air pollutants were associated with increased risk of asthma exacerbations in both single lag0 and lag1 exposure patterns [lag0: RR (95% CI) (pollutants), 1.057(1.011, 1.103) (air quality index, AQI), 1.007 (1.005, 1.010) (particulate matter of diameter ≤ 2.5 µm, PM2.5), 1.009 (1.005, 1.012) (particulate matter of diameter, PM10), 1.010 (1.006, 1.014) (NO2), 1.030 (1.011, 1.048) (CO), 1.005 (1.002, 1.009) (O3); lag1:1.064(1.022, 1.106) (AQI), 1.005 (1.002, 1.008) (PM2.5), 1.007 (1.004, 1.011) (PM10), 1.008 (1.004, 1.012) (NO2), 1.025 (1.007, 1.042) (CO), 1.010 (1.006, 1.013) (O3)], except SO2 [lag0: RR (95% CI), 1.004 (1.000, 1.007); lag1: RR (95% CI), 1.003 (0.999, 1.006)]. Subgroup analyses revealed stronger effects in children and asthma exacerbations associated with other events (including symptoms, lung function changes, and medication use).Conclusion: Outdoor air pollution increases the asthma exacerbation risk in single lag0 and lag1 exposure patterns.Trial registration: PROSPERO, CRD42020204097. https://www.crd.york.ac.uk/.Supplemental data for this article is available online at https://doi.org/10.1080/02770903.2021.2008429 .

Simulation of performance evaluation model for medical-elderly care integrated institutions based on system dynamics.

BACKGROUND: Based on the Chinese model of medical-elderly care integration, this paper aims to explore the impact of different investment levels on the performance of the medical-elderly care integrated institutions. METHODS: Using the method of system dynamics, this paper establishes the performance evaluation model of medical-elderly care integrated institutions, sets the system element input, service level, and policy support as the key factors, and uses Vensim PLE software for simulation. RESULTS: The three key factors have different degrees of positive impact on the performance of medical-elderly care integrated institutions. On the whole, policy support has the most significant impact on the performance of institutions, followed by the level of medical-elderly care integrated services. Institutional input mainly has a great impact on the performance of institutions in the early stage. In addition, the model simulation results also show the emergence effect: the improvement rate of institutional performance under the comprehensive simulation is higher than the sum of the improvement rates under the separate action of single factor. CONCLUSION: Government policies have played an important role in promoting the development of medical-elderly care integrated institutions. The service level and resource input can effectively promote the performance of medical-elderly care integrated institutions. Institutions should formulate development strategies from a systematic perspective, and pay attention to the integration of "medical" and "elderly care" resources.

The association of GATM polymorphism with statin-induced myopathy: a systematic review and meta-analysis.

PURPOSE: Statin-induced myopathy (SIM) is the commonest reason for discontinuation of statin therapy. The aim of this present meta-analysis is to assess the relationship between glycine amidinotransferase gene (GATM) polymorphism and risk of SIM. METHODS: MEDLINE, EMBASE, Web of Science, and Cochrane Library databases were searched systematically for case-control studies investigating the relationship between GATM polymorphism and SIM. Retrieved articles were carefully reviewed and assessed according to the inclusion criteria. Associations were assessed in pooled data by calculating odds ratio with 95% confidence intervals. Subgroup analysis was performed according to comedications and severity of SIM. RESULTS: Six studies with 707 cases and 2321 controls were included in this meta-analysis. GATM rs9806699 G>A was associated with decreased risk of SIM (OR = 0.80, 95% CI 0.68-0.94, P = 0.006). This association remained significant in the subgroup with fibrates or niacin excluded. However, the association of rs9806699 G>A with severe SIM was not significant. In addition, another two variations at GATM, rs1719247 C>T, and rs1346268 T>C were also associated with declined risk of SIM. CONCLUSIONS: GATM polymorphism including rs9806699 G>A, rs1719247 C>T, and rs1346268 T>C may be protective factors of SIM. GATM rs9806699 G>A may only exert protective effect on mild SIM cases. Our meta-analysis indicates that GATM polymorphism may represent a pharmacogenomics biomarker for predicting incidence of SIM, which contributes to risk stratification and optimizing statin adherence.

Lipid profiles and the risk of new-onset hypertension in a Chinese community-based cohort.

BACKGROUND AND AIMS: Dyslipidemia and hypertension, key risk factors for cardiovascular disease, may share similar pathophysiological processes. A longitudinal association was reported between dyslipidemia and new-onset hypertension, but few data were published in Asian. We aimed to investigate the association of lipid profiles with new-onset hypertension in a Chinese community-based non-hypertensive cohort without lipid-lowering treatment (n = 1802). METHODS AND RESULTS: New-onset hypertension was defined as any self-reported history of hypertension, systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg, or receiving antihypertensive medications at follow-up. Logistic regression models were used to evaluate the associations. Participants were aged 53.97 ± 7.49 years, 31.19% were men, and 64.54% with dyslipidemia. During a median of 2.30 years follow-up, the incidence of new-onset hypertension was 12.99%. Multivariate adjusted risks of new-onset hypertension increased with triglyceride increases (odds ratio [OR] = 1.14, 95% confidence interval [CI]: 1.03-1.27) and high-density lipoprotein cholesterol (HDL-C) decreases (OR = 0.47, 95% CI: 0.29-0.76) for one unit. However, threshold effects were observed for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and non-HDL-C. Compared with subjects with hyperlipidemia, in those with normal concentrations of TC, LDL-C, and non-HDL-C increased risks of new-onset hypertension were observed with OR (95% CI) of 1.65 (1.10-2.46), 1.58 (1.07-2.33), and 1.57 (1.15-2.15) for one unit increasement, respectively, after adjusting for all covariates. CONCLUSION: Higher TG and lower HDL-C increased the risk of new-onset hypertension, but for TC, LDL-C and non-HDLC, the risk of new-onset hypertension was increased only at normal concentrations in a Chinese community-based cohort.

Association Between Average Plasma Potassium Levels and 30-day Mortality During Hospitalization in Patients with COVID-19 in Wuhan, China.

Background: Coronavirus disease 2019 (COVID-19) has resulted in more than 610,000 deaths worldwide since December 2019. Given the rapid deterioration of patients' condition before death, markers with efficient prognostic values are urgently required. During the treatment process, notable changes in plasma potassium levels have been observed among severely ill patients. We aimed to evaluate the association between average plasma potassium (Ka +) levels during hospitalization and 30-day mortality in patients with COVID-19. Methods: Consecutive patients with COVID-19 hospitalized in the Zhongfaxincheng branch of Tongji Hospital in Wuhan, China from February 8 to 28, 2020 were enrolled in this study. We followed patients up to 30 days after admission. Results: A total of 136 patients were included in the study. The average age was 62.1±14.6 years and 51.5% of patients were male. The median baseline potassium level was 4.3 (3.9-4.6) mmol/L and Ka + level during hospitalization was 4.4 (4.2-4.7) mmol/L; the median number of times that we measured potassium was 4 (3-5). The 30-day mortality was 19.1%. A J-shaped association was observed between Ka + and 30-day mortality. Multivariate Cox regression showed that compared with the reference group (Ka + 4.0 to <4.5 mmol/L), 30-day mortality was 1.99 (95% confidence interval [CI]=0.54-7.35, P=0.300), 1.14 (95% CI=0.39-3.32, P=0.810), and 4.14 (95% CI=1.29-13.29, P=0.017) times higher in patients with COVID-19 who had Ka + <4.0, 4.5 to <5.0, and ≥5.0 mmol/L, respectively. Conclusion: Patients with COVID-19 who had a Ka + level ≥5.0 mmol/L had a significantly increased 30-day mortality compared with those who had a Ka + level 4.0 to <4.5 mmol/L. Plasma potassium levels should be monitored routinely and maintained within appropriate ranges in patients with COVID-19.

Associations between remnant lipoprotein cholesterol and central systolic blood pressure in a Chinese community-based population: a cross-sectional study.

BACKGROUND: The lipid profile is reportedly related to peripheral blood pressure or pulse wave velocity. However, no studies have investigated the associations between lipid parameters, especially remnant lipoprotein cholesterol (RLP-C), and central systolic blood pressure (cSBP). METHODS: This study used baseline data of a community-based cohort in Beijing, China. Participants who had been treated with anti-hypertensive or lipid-lowering agents were excluded. RLP-C is equal to total cholesterol (TC) minus the sum of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). An Omron HEM-9000AI device was used to measure non-invasive cSBP. The associations between blood lipid profile and non-invasive cSBP were evaluated using multivariable regression models. RESULTS: The 5173 included participants were 55.0 ± 8.5 years old; 35.7% (1845) of participants were men. Increased cSBP was significantly associated with increased TC, LDL-C, non-high-density lipoprotein cholesterol (non-HDL-C), triglyceride (TG), and RLP-C but with decreased HDL-C, even after adjusting for possible covariates. When simultaneously entering individual pairs of RLP-C and other blood lipid parameters into the multivariable regression model, RLP-C remained significantly associated with cSBP, even after adjusting for other lipids. Compared with participants who had RLP-C levels in the first quartile (Q1), cSBP for those with RLP-C in Q4 was increased to 4.57 (95% confidence interval [CI]: 3.08-6.06) mmHg after adjusting for LDL-C, 4.50 (95%CI: 2.98-6.02) mmHg after adjusting for TC, 3.91 (95%CI: 1.92-5.89) mmHg after adjusting for TG, 5.15 (95%CI: 3.67-6.63) mmHg after adjusting for HDL-C, and 4.10 (95%CI: 2.36-5.84) mmHg after adjusting for non-HDL-C. CONCLUSIONS: Increased blood RLP-C level was significantly associated with higher cSBP in a Chinese population, independently of other lipids, which indicates its importance in individual cardiovascular risk assessment.