Novel metal peroxide nanoboxes restrain Clostridioides difficile infection beyond the bactericidal and sporicidal activity

Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl- and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag-Au peroxide coat covering Au shell and AgCl core (AgAu-based nanoboxes). The AgAu-based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30-45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au-enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide-derived AgAu-based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.

INTERIM ANALYSIS OF PRIMARY HEALTHCARE SPECIALISTS TRAINING IN THE UNIVERSALLY PROGRESSIVE MODEL OF HOME-BASED SERVICES: ANTICIPATED PROSPECTS IN THE SOCIAL AREA

This is an overview of the Interim analysis of primary healthcare specialists training in a universally progressive model of home-based services in the city of Astana, Akmola, and North Kazakhstan regions. A total of 482 persons were trained. Questionnaires filled in by trainees were analyzed.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Unleashing the full power of LHCb to probe stealth new physics

In this paper, we describe the potential of the LHCb experiment to detect stealth physics. This refers to dynamics beyond the standard model that would elude searches that focus on energetic objects or precision measurements of known processes. Stealth signatures include long-lived particles and light resonances that are produced very rarely or together with overwhelming backgrounds. We will discuss why LHCb is equipped to discover this kind of physics at the Large Hadron Collider and provide examples of well-motivated theoretical models that can be probed with great detail at the experiment.

A32 THE REGULATION OF INTESTINAL SMOOTH MUSCLE CELL PROLIFERATION IN CROHN’S DISEASE – IS NR4A1 A NOVEL TARGET TO TREAT FIBROSTENOSIS?

Background

Intestinal fibrosis and stricture formation are common complications of Crohn’s disease (CD). Recently, the stricturing phenotype has been recognized to be primarily attributable to hypertrophy/hyperplasia of smooth muscle, rather than an increase in fibrosis alone. Despite advances in treatment of CD, current therapies do little to prevent or reverse strictures. NR4A1 is an orphan nuclear receptor that has been reported as anti-fibrotic in non-intestinal systems and exhibits anti-proliferative effects in smooth muscle cells (SMCs). NR4A1 gene variants have been associated with increased risk of IBD, however, the mechanisms regulating NR4A1 expression and its role in intestinal SMC function has not been investigated.

Aims

To characterize and understand the role of NR4A1 activation in the regulation of mitogen-induced proliferation of intestinal SMCs.

Methods

Primary intestinal SMCs were isolated from Nr4a1+/+ and Nr4a1-/- mice. Furthermore, a commercially sourced human primary intestinal SMC line was used. To assess the response of SMCs to culture and identify growth differences, proliferation was measured via trypan blue exclusion and EdU incorporation. In mouse and human SMCs, proliferation was induced by platelet-derived growth factor-BB (PDGF-BB) and NR4A1 activation was assessed by pretreating with selective agonists, cytosporone B (Csn-B) and 6-mercaptopurine (6-MP), at various concentrations. Mass spectrometry was used to characterize proteomic differences between Nr4a1+/+ and Nr4a1-/- SMCs. Expression levels of NR4A1 were assessed by qPCR and western blot after mitogen exposure and Csn-B treatment.

Results

Nr4a1-/- cells exhibited a significantly higher rate of proliferation compared to Nr4a1+/+ cells, under both basal and mitogen-exposed conditions. Proteomic analysis showed that Nr4a1-/- SMCs exhibited increased expression of proteins related to the cell cycle and metabolism, compared to Nr4a1+/+ SMCs. Pretreating human intestinal SMCs with Csn-B and 6-MP significantly attenuated proliferation induced by PDGF-BB. Similar effects were observed in Nr4a1+/+ SMCs, however, the anti-proliferative effect of Csn-B was absent in Nr4a1-/- cells. Furthermore, NR4A1 expression was rapidly induced by Csn-B and PDGF-BB, the latter response suggesting the existence of a potential negative feedback mechanism to control mitogen-induced SMC proliferation.

Conclusions

Our results suggest that NR4A1 is a critical regulator of intestinal SMC proliferation and its induction by mitogens may contribute to a negative feedback loop to control smooth muscle growth. These data support targeting NR4A1 to treat excessive smooth muscle hypertrophy/hyperplasia that contributes to tissue remodelling observed in fibrostenotic CD.

Funding Agencies

CAG, CCC, CIHR

P2752Impact of different antithrombotic regimens on the outcomes of bioprosthetic valve replacement in elderly asian population

Background

Lifelong antithrombotic therapy is necessary for patients undergoing mechanical valve replacement. However, the optimal regimen and duration of antithrombotic agents are still controversial for patients underwent bioprosthetic valve replacement.

Purpose

We investigated the effect of different antithrombotic strategies on the prognosis of patients underwent bioprosthetic valve replacement in the elder Asian population.

Methods

Based on the National Health Insurance Database in Taiwan, 1227 patients elderly than 50 years-old and underwent bioprosthetic valve replacement between 2003 to 2010 were enrolled for analysis. Patients were classified according to their antithrombotic therapies within 3 months after bioprosthetic valve replacements.

Results

The 1227 patients were stratified to three groups, including aspirin alone (19.6%), warfarin alone (60.6%), and the combined use of aspirin and warfarin (19.9%) within 3 months after surgery. After adjusting propensity scores, the warfarin group (relative risk: 0.69, 95% CI: 0.54–0.88) and the combination group (relative risk: 0.57, 95% CI: 0.42–0.79) both had lower mortality rate compared to the aspirin alone group. Neither increasing major bleeding risk (adjusted relative risk: 0.62, 95% CI: 0.15–2.68) nor decreasing ischemic stroke risk (adjusted relative risk: 0.64, 95% CI: 0.36–1.14) was noticed in the combination group.

Incidence and risk of antithrombotics Crude Model 1 Model 2 Hazard Ratio (95% CI) p-value Hazard Ratio (95% CI) p-value Hazard Ratio (95% CI) p-value All cause mortality   Antiplatelet user Reference Reference Reference   Warfarin user 0.65 (0.52–0.81) <0.001 0.71 (0.56–0.91) 0.006 0.69 (0.54–0.88) 0.002   Antiplatelet + warfarin user 0.59 (0.44–0.81) 0.001 0.63 (0.46–0.85) 0.003 0.57 (0.42–0.79) 0.001   Ischemic stroke antiplatelet user as reference   Warfarin user 0.77 (0.51–1.17) 0.224 0.85 (0.55–1.33) 0.485 0.82 (0.52–1.27) 0.369   Antiplatelet + warfarin user 0.63 (0.36–1.10) 0.102 0.67 (0.38–1.21) 0.185 0.64 (0.36–1.14) 0.130   Major bleeding antiplatelet user as reference   Warfarin user 0.32 (0.10–1.05) 0.061 0.71 (0.14–3.60) 0.674 0.40 (0.11–1.40) 0.150   Antiplatelet + warfarin user 0.57 (0.14–2.39) 0.444 1.56 (0.26–9.46) 0.627 0.62 (0.15–2.68) 0.526 Model 1: Adjusted for all covariates; Model 2: Adjusted for propensity score of using warfarin.

Conclusion

Comparing with aspirin alone, warfarin only or combined warfarin with aspirin therapy have a lowering one-year all-cause mortality rate without increasing the occurrence of bleeding events.

P3418The relationship between circulating vitamin d3 and subclinical atherosclerosis in elderly asian: contributor or bystander?

Background

Vitamin D deficiency had been suggested to be the risk factor of cardiovascular diseases and metabolic disorders. However, current evidence about the association between vitamin D deficiency and atherosclerosis are conflicted and inconclusive.

Purpose

We tried to investigate the relationship between serum vitamin D concentrations and subclinical atherosclerosis in the elderly Asian population.

Methods

The I-Lan longitudinal study (ILAS), 1798 community-dwelling adults older than 50 years old were enrolled and divided into two groups according to serum vitamin D level (sufficient, ≥20 ng/mL, and deficient <20 ng/mL). The concentrations of serum vitamin D3 was measured by chemiluminescence immunoassay and demographic data recorded from chart review. The carotid intima-media thickness (cIMT) was measured at bilateral common carotid arteries. Subclinical atherosclerosis was defined as mean cIMT more than 0.81mm, which had been proved to be associated with an increased risk of stroke and coronary events.

Results

Subjects with vitamin D deficiency (n=604, 33.6%) were younger, composed of more woman, smoker, with a higher incidence of hypertension, dyslipidemia, and metabolic syndrome. Compared with subjects without vitamin D sufficiency, patients with vitamin D deficiency were associated with lower risk of subclinical atherosclerosis (crude OR: 0.63, 95% CI: 0.50–0.81, p<0.001) in the univariate analysis. However, after adjusting gender and age, vitamin D deficiency was no more associated with risk of subclinical atherosclerosis.

Risk of vitD3 and cIMT Subclinical Atherosclerosis (cIMT >0.8mm) Odds Ratio 95% Confidence Interval p-value Model 1   Vit D3 normal (≥20) Reference – –   Vit D3 deficiency (<20) 0.63 0.50–0.81 <0.001 Model 2   Vit D3 normal (≥20) Reference – –   Vit D3 deficiency (<20) 0.81 0.62–1.06 0.127 Model 3   Vit D3 normal (≥20) Reference – –   Vit D3 deficiency (<20) 0.93 0.69–1.24 0.599 Model 1: adjust for vit D3 (univariate); Model 2: adjusted for age, vit D3, Gender; Model 3: adjusted multivariate significantly in univariate analysis.

Conclusion

Vitamin D deficiency was not an independent risk factor for subclinical atherosclerosis in the elderly Asian population. The association observed in the univariate analysis may be confounded by gender difference or comorbidities.

Zinc Deficiency and Long-Term Outcome in Cases After Isolated Intestinal Transplantation in Taiwan

OBJECTIVES

The small intestine is the primary site for absorption of dietary zinc. Intestinal transplant recipients are at high risk for zinc deficiency because of the long process of posttransplant adaptation. We initiated an intestinal transplant program in Taiwan in 2007. In this study, we aimed to retrospectively investigate the incidence of zinc deficiency in recipients after intestinal transplantation.

METHODS

Twenty-one isolated intestinal transplants were performed in 20 patients with 1 retransplantation. The level of serum zinc was monitored periodically, and zinc supplements were administered when zinc level was below 700 ng/mL. Twelve patients with graft above 1-year survival and with available related data were enrolled for the analysis of zinc deficiency. The levels of serum zinc were tracked, and the protocol of zinc supplementation is discussed herein.

RESULTS

The survival rates of 20 transplant recipients for 1 year, 3 years, and 5 years were 85%, 75%, and 65%, respectively. In the 12 grafts that survived longer than 1 year, we found that zinc deficiency was highest during the third (41.7%) to sixth (50%) month after transplantation. Sustained supplementation of zinc was required for over 70% of patients throughout the 3-year period to maintain their zinc level around the lower normal limit.

CONCLUSION

The outcome of isolated small bowel transplantation is promising. Periodical monitoring and sufficient dosing of zinc supplements should be considered into the posttransplant protocol to prevent zinc deficiency after intestinal transplantation.

Magnetoluminescence and valley polarized state of a two-dimensional electron gas in WS2 monolayers

Materials often exhibit fundamentally new phenomena in reduced dimensions that potentially lead to novel applications. This is true for single-layer, two-dimensional semiconductor crystals of transition-metal dichalcogenides, MX2 (M = Mo, W and X = S, Se). They exhibit direct bandgaps with energies in the visible region at the two non-equivalent valleys in the Brillouin zone. This makes them suitable for optoelectronic applications that range from light-emitting diodes to light harvesting and light sensors, and to valleytronics. Here, we report the results of a magnetoluminescence study of WS2 single-layer crystals in which the strong spin-orbit interaction additionally locks the valley and spin degrees of freedom. The recombination of the negatively charged exciton in the presence of a two-dimensional electron gas (2DEG) is found to be circularly polarized at zero magnetic field despite being excited with unpolarized light, which indicates that the existence of a valley polarized 2DEG is caused by valley and spin locking and strong electron-electron interactions.

The burden of influenza-like illness in the US workforce

BACKGROUND

The disease burden of influenza-like illnesses (ILIs) on the working population has been documented in the literature, but statistical evidence of ILI-related work absenteeism in the USA is limited due to data availability.

AIMS

To assess work absenteeism due to ILIs among privately insured employees in the USA in 2007-8 and 2008-9.

METHODS

We used the 2007-9 MarketScan® research databases. Full-time employees aged 18-64 years, with the ability to incur work absence and continuously enrolled in the same insurance plan during each season were included. We identified ILI episodes using ICD-9 codes for influenza and pneumonia (480-487). For each season, we calculated the mean work-loss hours per ILI episode and the proportion of employees who had at least one ILI episode. Work-loss hours and ILI rates were examined by subgroups.

RESULTS

The mean number of work hours lost per ILI episode was 23.6 in 2007-8 and 23.9 in 2008-9. The proportion of employees with at least one ILI was 1.7% in 2007-8 and 1.2% in 2008-9. In both seasons, the proportion with ILI was higher among older (2.1 and 1.5%) and hourly workers (2.0 and 1.3%), workers in the southern region (1.9 and 1.3%) and those in oil, gas or mining industries (1.9 and 1.4%).

CONCLUSIONS

Our results indicate that the disease burden associated with ILIs in the working population is not trivial and deserves attention from policymakers and health care professionals to design effective strategies to reduce this burden.

Effect of AbGn-7, a glycotope-specific monoclonal antibody, on apoptosis in colon cancer cells and tumor growth in xenograft models

e15118

Background: While clinical benefit against colorectal cancer has been observed with therapeutic monoclonal antibodies such as bevacizumab, cetuximab and panituzumab, the death rate of advanced colorectal cancer remains high that warrants further development of more potent therapeutics. Methods: A cell-based immunization approach was used to generate monoclonal antibodies against targets expressed on human colorectal cancer cells. A chimeric monoclonal antibody, AbGn-7, was selected and evaluated for the potential clinical use to treat colorectal cancer. Results: Expression of AbGn-7 antigen: Carbohydrate competition assay demonstrated that AbGn-7 recognizes a Lewis-A-like carbohydrate antigen (AbGn-7 antigen). Immunohistochemical studies showed that AbGn-7 antigen is expressed in colorectal cancer tissue. No significant binding could be detected in non-tumor tissues except in the epithelia of GI track. Effector function of AbGn-7: AbGn-7 triggered dose-dependent apoptosis in COLO 205 colon cancer cell. In addition, AbGn-7 elicited potent complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) in a dose-dependent manner. Molecular mechanism of apoptosis induced by AbGn-7: Tunel assay, PARP cleavage assay as well as caspase inhibitor studies demonstrated that AbGn-7 induced apoptosis in COLO 205 colon cancer cells via a caspase-independent pathway. Xenograft study: AbGn-7 alone, or in combination with 5FU-Leucovorin, effectively inhibited the growth of COLO 205 xenograft in SCID mice and prolonged their survival. Conclusions: The results of the present study suggest that AbGn-7 is a potential candidate for effective treatment of colorectal cancer.

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