Biotechnological Production and Characterization of Extracellular Melanin by Streptomyces nashvillensis.

Melanins are pigments employed in food, cosmetic, and textile industries, manufactured by extraction from cuttlefishes. Their biotechnological production by Streptomycetes, instead, has been poorly investigated so far. In this paper, for the first time, the strain Streptomyces nashvillensis DSM 40314 was tested as an extracellular melanin producer by investigating the influence of diverse temperatures (26, 28, and 30 °C) and pH values (6.0 and 7.0) on bacterial growth, melanin production, and on the activity of the secreted tyrosinase, the first enzyme of the pigment biosynthetic pathway. In physiological 96-h shake flask experiments, the optimal growth parameters resulted to be 28 °C and pH 7.0, at which a maximum biomass of 8.4 ± 0.5 gcdw/L, a melanin concentration of 0.74 ± 0.01 g/L (yield on biomass of 0.09 ± 0.01 g/gcdw and productivity of 0.008 ± 0.001 g/L/h), and a final tyrosinase activity of 10.1 ± 0.1 U/mL were reached. The produced pigment was purified from the broth supernatant with a two-step purification process (75.0 ± 2.0% of purity with 65.0 ± 5.0% of recovery) and tested for its chemical, antioxidant, and photoprotective properties. Finally, characterization by UV-visible and FT-IR spectroscopy, elemental analyses, and mono- and bi-dimensional NMR suggested the eumelanin-like nature of the pigment.

Improving Asthma Action Plan Completion Rates across Five Divisions in an Academic Children's Hospital.

Introduction: Asthma is the most common chronic disease among children. Asthma Action Plans (AAPs) enable asthma self-management tailored to each patient and should be updated annually. At our institution, providers face challenges in creating reliable processes to consistently complete AAPs for patients with asthma. This project's aim was to increase the percentage of patients across five hospital divisions who have an up-to-date AAP from 80% in May 2021 to 85% by October 1, 2021. Methods: We launched a quality improvement (QI) project using the Model for Improvement, focusing on improving AAP completion rates across five hospital divisions providing ambulatory care for asthma patients. The divisions (Adolescent/Young Adult Medicine, Allergy, Pulmonary, and two Primary Care sites) participated in the QI process using tools to understand the problem context. They implemented a cross-divisional AAP completion competition from June to October 2021. Each month during Action Periods, divisions trialed their interventions using Plan-Do-Study-Act cycles. We held monthly Learning Sessions for divisions to collaborate on successful intervention strategies. Results: Statistical process control chart analysis demonstrated that the overall AAP completion rate increased from a baseline of 80% to 87% with the initiation of the competition. All divisions showed improvement in AAP completion rates during the active intervention period, but sustainment varied. Conclusions: The cross-divisional competition motivated five divisions to improve processes to increase AAP completion rates. This approach effectively fostered engagement and idea sharing to boost performance, and may be considered for other QI projects.

The Multifaceted Opportunities Provided by the Pheomelanin-Inspired 1,4-Benzothiazine Chromophore: A Still-Undervalued Issue.

1,4-Benzothiazines are the main building blocks of the naturally occurring pheomelanin pigments, and their chromophoric properties have been strongly related to the well-known phototoxicity of these pigments, partly responsible for the high incidence of melanoma and other skin cancers in red-haired people. However, some peculiar features of the 1,4-benzothiazine chromophore could be functionally exploited in several sectors. Within this context, in this perspective, an overview of the very recently reported applications of the 1,4-benzothiazine chromophore in pH sensing, filter permeability control, smart packaging, electrochromic device fabrication, bioimaging, photocatalysis, and HPLC detection systems is provided, together with a brief presentation of recently developed synthetic approaches to the 1,4-benzothiazine scaffold, with the aim of emphasizing the still-undervalued multifunctional opportunities offered by this class of compounds.

Highly Functionalized SWCNTs with a Dopamine Derivative as a Support for Pd Nanoparticles: A Recyclable Catalyst for the Reduction of Nitro Compounds and the Heck Reaction.

Single-walled carbon nanotubes (SWCNTs) were functionalized with a dopamine derivative in which the amine group was converted to azide (dopamine azide). The direct reaction of SWCNTs and dopamine azide in o-dichlorobenzene at high temperature (160 °C) led to very highly functionalized CNTs (≈60 wt.%). Surprisingly, despite this high degree of functionalization, Raman spectroscopy detected a low disruption of the π-network of the carbonaceous support. This finding was justified by the rehybridization from sp3 to sp2 of the sidewall carbon atoms of CNTs involved in the functionalization process. Further characterization by means of different techniques such as X-ray photoelectron spectroscopy (XPS) analysis and transmission electron microscopy (TEM) allowed to shed some light on the chemical composition and morphology of the obtained material. Moreover, the estimation of the total content of phenolic units and their reducing potential after CNTs functionalization was also assessed using Folin and Ciocalteu and 2,2-diphenyl-1-picryl hydrazide (DPPH) assays. The functionalization of CNTs was exploited to immobilize palladium(II) species that were subsequently reduced with NaBH4 leading to the formation of Pd nanoparticles (NPs). The so obtained hybrid material was used as a recyclable heterogeneous catalyst for the reduction of nitro compounds and the Heck reaction.

Deposition of Antioxidant and Cytocompatible Caffeic Acid-Based Thin Films onto Ti6Al4V Alloys through Hexamethylenediamine-Mediated Crosslinking.

A promising approach for advanced bone implants is the deposition on titanium surfaces of organic thin films with improved therapeutic performances. Herein, we reported the efficient dip-coating deposition of caffeic acid (CA)-based films on both polished and chemically pre-treated Ti6Al4V alloys by exploiting hexamethylenediamine (HMDA) crosslinking ability. The formation of benzacridine systems, resulting from the interaction of CA with the amino groups of HMDA, as reported in previous studies, was suggested by the yellow/green color of the coatings. The coated surfaces were characterized by means of the Folin-Ciocalteu method, fluorescence microscopy, water contact angle measurements, X-ray photoelectron spectroscopy (XPS), zeta-potential measurements, and Fourier transform infrared spectroscopy, confirming the presence of a uniform coating on the titanium surfaces. The optimal mechanical adhesion of the coating, especially on the chemically pre-treated substrate, was also demonstrated by the tape adhesion test. Interestingly, both films exhibited marked antioxidant properties (2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays) that persisted over time and were not lost even after prolonged storage of the material. The feature of the coatings in terms of the exposed groups (XPS and zeta potential titration evidence) was apparently dependent on the surface pre-treatment of the titanium substrate. Cytocompatibility, scavenger antioxidant activity, and antibacterial properties of the developed coatings were evaluated. The most promising results were obtained in the case of the chemically pre-treated CA/HMDA-based coated surface that showed good cytocompatibility and high reactive oxygen species' scavenging ability, preventing their intracellular accumulation under pro-inflammatory conditions; moreover, an anti-fouling effect preventing the formation of 3D biofilm-like bacterial aggregates was observed by scanning electron microscopy. These results open new perspectives for the development of innovative titanium surfaces with thin coatings from naturally occurring phenols for bone contact implants.

Modification of halloysite lumen with dopamine derivatives as filler for antibiofilm coating.

HYPOTHESIS: Development of nanocomposite coating with antibiofilm properties is of fundamental importance to efficient fight biofilm formation preventing infections in biomedical area. In this context, halloysite nanotubes (HNTs), biocompatible and low-cost clay mineral, have been efficiently used as filler for different polymeric matrices affording several nanocomposites with appealing antimicrobial properties. The modification of HNTs surfaces represents a valuable strategy to improve the utilization of the clay for biological purposes. EXPERIMENTS: Herein, the covalent modification of the HNTs lumen with properly designed dopamine derivatives with different perfluoroalkyl chain length is reported. The obtained nanomaterials are thoroughly characterized by several techniques. As proof of concept the antibiofilm properties on E. coli strain of the nanomaterials are assayed as well. Finally, the HNTs fillers were introduced into a polydopamine matrix allowing for the preparation of functional coatings, resistant to formation of microbial biofilms. FINDINGS: All characterization methods proved the selectivity of the modification and the increased hydrophobicity of the lumen. In particular 27Al solid state nuclear magnetic resonance (NMR) spectra showed a upfield shift of the Al signal. Studies on the antibiofilm properties highlighted different activities according to the length of perfluoroalkyl chains of organic molecules as proved by 19F solid state NMR spectra. The synthetized materials were promising for future application as coatings on medical implants.

A sepsis trigger tool reduces time to antibiotic administration in the NICU.

OBJECTIVE: Prolonged time to antibiotic administration is associated with increased morbidity and mortality. Interventions to decrease the time to antibiotic administration may improve mortality and morbidity. STUDY DESIGN: We identified possible change concepts for reducing time to antibiotic usage in the NICU. For the initial intervention, we developed a sepsis screening tool based on NICU-specific parameters. The main goal of the project was to reduce time to antibiotic administration by 10%. RESULTS: The project was conducted from April 2017 until April 2019. There were no missed cases of sepsis in the project period. Time to antibiotic administration for patients who were started on antibiotics decreased during the project, with the mean shifting from 126 to 102 min, a reduction of 19%. CONCLUSIONS: We successfully reduced time to antibiotic delivery in our NICU using a trigger tool to identifying potential cases of sepsis in the NICU environment. The trigger tool requires broader validation.

Implication of Cellular Senescence in Osteoarthritis: A Study on Equine Synovial Fluid Mesenchymal Stromal Cells.

Osteoarthritis (OA) is described as a chronic degenerative disease characterized by the loss of articular cartilage. Senescence is a natural cellular response to stressors. Beneficial in certain conditions, the accumulation of senescent cells has been implicated in the pathophysiology of many diseases associated with aging. Recently, it has been demonstrated that mesenchymal stem/stromal cells isolated from OA patients contain many senescent cells that inhibit cartilage regeneration. However, the link between cellular senescence in MSCs and OA progression is still debated. In this study, we aim to characterize and compare synovial fluid MSCs (sf-MSCs), isolated from OA joints, with healthy sf-MSCs, investigating the senescence hallmarks and how this state could affect cartilage repair. Sf-MSCs were isolated from tibiotarsal joints of healthy and diseased horses with an established diagnosis of OA with an age ranging from 8 to 14 years. Cells were cultured in vitro and characterized for cell proliferation assay, cell cycle analysis, ROS detection assay, ultrastructure analysis, and the expression of senescent markers. To evaluate the influence of senescence on chondrogenic differentiation, OA sf-MSCs were stimulated in vitro for up to 21 days with chondrogenic factors, and the expression of chondrogenic markers was compared with healthy sf-MSCs. Our findings demonstrated the presence of senescent sf-MSCs in OA joints with impaired chondrogenic differentiation abilities, which could have a potential influence on OA progression.

Impact of a Documented Penicillin Allergy on Antibiotic Selection in Pediatric Patients With Osteomyelitis.

Penicillin allergy labels are common in hospitalized patients, and there is a frequent misconception that these patients cannot receive cephalosporins. Through retrospective review, we found that patients with reported penicillin allergies were significantly less likely to receive first-line therapy for acute hematogenous osteomyelitis.

A Model Eumelanin from 5,6-Dihydroxyindole-2-Carboxybutanamide Combining Remarkable Antioxidant and Photoprotective Properties with a Favourable Solubility Profile for Dermo-Cosmetic Applications.

The search for new synthetic melanin-related pigments that maintain the antioxidant and photoprotective properties of naturally occurring dark eumelanins, while overcoming their unfavorable solubility, and molecular heterogeneity is presently a very active issue for dermo-cosmetic purposes. In this work, we explored the potential of a melanin obtained from the carboxybutanamide of a major eumelanin biosynthetic precursor, 5,6-dihydroxyindole-2-carboxylic acid (DHICA), by aerobic oxidation under slightly alkaline conditions. Analysis of the pigment by EPR, ATR-FTIR and MALDI MS indicated a substantial structural similarity to DHICA melanin, while investigation of the early intermediates confirmed unchanged regiochemistry of the oxidative coupling. The pigment exhibited a UVA-visible absorption even more intense than that of DHICA melanin, and a noticeable solubility in polar solvents of dermo-cosmetic relevance. The hydrogen- and/or electron-donor ability, and the iron (III) reducing power as determined by conventional assays provided evidence for marked antioxidant properties not merely ascribable to the more favorable solubility profile, while the inhibitory action of the radical- or photosensitized solar light-induced lipid peroxidation was more marked compared to that of DHICA melanin. Overall, these results hint at this melanin, which remarkable properties are, in part, due to the electronic effects of the carboxyamide functionality as a promising functional ingredient for dermo-cosmetic formulations.

Hands-on synthesis of furanamides and evaluation of their antimicrobial activity.

Diverse natural and synthetic furan derivatives have shown biological activity. Here, we describe the preparation of benzyl and arylethyl ß-furanamides with OH or OMe aryl substituents by an adapted sustainable method from a furoic acid using methyl chloroformate. Symmetric and asymmetric ß,ß'-furanamides have instead been prepared using azabenzotriazole based catalyst (HATU). The products have been evaluated for their antimicrobial properties on Gram positive and Gram negative bacteria. Just a minimal not-significant activity has been observed in some derivatives.

Quality Improvement Initiative to Improve Timing of Enteral Feeds in Pediatric Acute Pancreatitis.

BACKGROUND: Acute pancreatitis (AP) represents a significant disease burden in the pediatric population. The management of AP includes fluid resuscitation, pain management, and early enteral feeds. Contrary to old dogma, early enteral feeding has been shown to improve outcomes and reduce hospital length of stay (LOS), yet uptake of this approach has not been standardized. Our aim was to standardize the management of AP, increasing the percentage of patients receiving early enteral nutrition from 40% to 65% within 12 months. METHODS: Between January 2013 and September 2021, we conducted a quality improvement initiative among patients hospitalized with AP. Interventions included the development of a clinical care pathway, integration of an AP order set, and physician education. Our primary outcome was the percentage of patients receiving enteral nutrition within 48 hours of admission, and our secondary outcome was hospital LOS. Balancing measures included hospital readmission rates. RESULTS: A total of 652 patients were admitted for AP during the project, of which 322 (49%) were included after pathway implementation. Before pathway development, the percentage of patients receiving early enteral nutrition was 40%, which increased significantly to 84% after our interventions. This improvement remained stable. Median LOS decreased significantly from 5.5 to 4 days during this timeframe. Our balancing measure of readmission rates did not change during the project period. CONCLUSIONS: Through multiple interventions, including the implementation of an AP clinical pathway, we significantly increased the proportion of patients receiving early enteral nutrition and decreased hospital LOS without increasing hospital readmission rates.

Longitudinal assessment of preparation for care transition among adolescents and young adults with rheumatologic disease: a single-center pilot study.

Adolescents and young adults (AYA) with rheumatologic diseases are at high risk for poor outcomes and gaps in care when transitioning from pediatric to adult care. However, tools for evaluating transition readiness and assessing the impact of transition interventions are limited. We implemented a written transition policy at our pediatric rheumatology center and evaluated preparation for transition among AYA 16 and older before and after distribution. 31 of 77 patients completed the follow-up survey (response rate 40%). Patient report of transition counseling increased following written transition policy implementation, though these results were not statistically significant in our small cohort. Most follow-up respondents (n = 19, 61%) had not yet completed care transfer; 4 (13%) had arranged a visit with an adult rheumatologist and 8 (26%) had fully transitioned to adult care. Those who successfully completed care transfer were older, had completed higher levels of education, and had significantly higher baseline transition preparation scores compared to those with no transfer arranged or planned visit only. Our single-center pilot study demonstrated that longitudinal assessment of transition preparation is feasible and that scores are significantly associated with care transfer outcomes. Tracking transition preparation over time may provide practices with information on areas of highest need for transition guidance and predict successful transfer among AYA with rheumatologic disease.

An Evidence-Based Guideline Improves Outcomes for Patients With Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome.

OBJECTIVE: To compare clinical outcomes in children with hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) who were managed before and after implementation of an evidence-based guideline (EBG). METHODS: A management algorithm for MAS-HLH was developed at our institution based on literature review, expert opinion, and consensus building across multiple pediatric subspecialties. An electronic medical record search retrospectively identified hospitalized patients with MAS-HLH in the pre-EBG (October 15, 2015, to December 4, 2017) and post-EBG (January 1, 2018, to January 21, 2020) time periods. Predetermined outcome metrics were evaluated in the 2 cohorts. RESULTS: After the EBG launch, 57 children were identified by house staff as potential patients with MAS-HLH, and rheumatology was consulted for management. Ultimately, 17 patients were diagnosed with MAS-HLH by the treating team. Of these, 59% met HLH 2004 criteria, and 94% met 2016 classification criteria for MAS complicating systemic juvenile idiopathic arthritis. There was a statistically significant reduction in mortality from 50% before implementation of the EBG to 6% in the post-EBG cohort (P = 0.02). There was a significant improvement in time to 50% reduction in C-reactive protein level in the post-EBG vs pre-EBG cohorts (log-rank P < 0.01). There were trends toward faster time to MAS-HLH diagnosis, faster initiation of immunosuppressive therapy, shorter length of hospital stay, and more rapid normalization of MAS-HLH-related biomarkers in the patients post-EBG. CONCLUSION: While the observed improvements may be partially attributed to advances in treatment of MAS-HLH that have accumulated over time, this analysis also suggests that a multidisciplinary treatment pathway for MAS-HLH contributed meaningfully to favorable patient outcomes.

Non-covalent small molecule partnership for redox-active films: Beyond polydopamine technology.

HYPOTHESIS: The possibility to use hexamethylenediamine (HMDA) to impart film forming ability to natural polymers including eumelanins and plant polyphenols endowed with biological activity and functional properties has been recently explored with the aim to broaden the potential of polydopamine (PDA)-based films overcoming their inherent limitations. 5,6-dihydroxyindole-2-carboxylic acid, its methyl ester (MeDHICA) and eumelanins thereof were shown to exhibit potent reducing activity. EXPERIMENTS: MeDHICA and HMDA were reacted in aqueous buffer, pH 9.0 in the presence of different substrates to assess the film forming ability. The effect of different reaction parameters (pH, diamine chain length) on film formation was investigated. Voltammetric and AFM /SEM methods were applied for analysis of the film redox activity and morphology. HPLC, MALDI-MS and 1HNMR were used for chemical characterization. The film reducing activity was evaluated in comparison with PDA by chemical assays and using UV stressed human immortalized keratinocytes (HaCat) cells model. FINDINGS: Regular and homogeneous yellowish films were obtained with moderately hydrophobic properties. Film deposition was optimal at pH 9, and specifically induced by HMDA. The film consisted of HMDA and monomeric MeDHICA accompanied by dimers/small oligomers, but no detectable MeDHICA/HMDA covalent conjugation products. Spontaneous assembly of self-organized networks held together mainly by electrostatic interactions of MeDHICA in the anion form and HMDA as the dication is proposed as film deposition mechanism. The film displayed potent reducing properties and exerted significant protective effects from oxidative stress on HaCaT.

Polydopamine at biological interfaces.

In the last years coating of surfaces in the presence of dopamine or other catecholamines in oxidative conditions to yield "polydopamine" films has become a popular, easy and versatile coating methodology. Polydopamine(s) offer(s) also a rich chemistry allowing to post-functionalize the obtained coatings with metal nanoparticles with polymers and proteins. However, the interactions either of covalent or non-covalent nature between polydopamine and biomolecules has only been explored more recently. They allow polydopamine to become a material, in the form of nanoparticles, membranes and other assemblies, in its own right not just as a coating. It is the aim of this review to describe the most recent advances in the design of composites between polydopamine and related eumelanin like materials with biomolecules like proteins, nucleotides, oligosaccharides and lipid assemblies. Furthermore, the interactions between polydopamine and living cells will be also reported.

Disentangling the Puzzling Regiochemistry of Thiol Addition to o-Quinones.

The addition of thiol compounds to o-quinones, as exemplified by the biologically relevant conjugation of cysteine to dopaquinone, displays an anomalous 1,6-type regiochemistry compared to the usual 1,4-nucleophilic addition, for example, by amines, which has so far eluded intensive investigations. By means of an integrated experimental and computational approach, herein, we provide evidence that the addition of glutathione, cysteine, or benzenethiol to 4-methyl-o-benzoquinone, modeling dopaquinone, proceeds by a free radical chain mechanism triggered by the addition of thiyl radicals to the o-quinone. In support of this conclusion, DFT calculations consistently predicted the correct regiochemistry only for the proposed thiyl radical-quinone addition pathway. These results would prompt a revision of the commonly accepted mechanisms for thiol-o-quinone conjugation and stimulate further work aimed at assessing the impact of the free radical processes in biologically relevant thiol-quinone interactions.

Role of Sulphur and Heavier Chalcogens on the Antioxidant Power and Bioactivity of Natural Phenolic Compounds.

The activity of natural phenols is primarily associated to their antioxidant potential, but is ultimately expressed in a variety of biological effects. Molecular scaffold manipulation of this large variety of compounds is a currently pursued approach to boost or modulate their properties. Insertion of S/Se/Te containing substituents on phenols may increase/decrease their H-donor/acceptor ability by electronic and stereo-electronic effects related to the site of substitution and geometrical constrains. Oxygen to sulphur/selenium isosteric replacement in resveratrol or ferulic acid leads to an increase in the radical scavenging activity with respect to the parent phenol. Several chalcogen-substituted phenols inspired by Vitamin E and flavonoids have been prepared, which in some cases prove to be chain-breaking antioxidants, far better than the natural counterparts. Conjugation of catechols with biological thiols (cysteine, glutathione, dihydrolipoic acid) is easily achieved by addition to the corresponding ortho-quinones. Noticeable examples of compounds with potentiated antioxidant activities are the human metabolite 5-S-cysteinyldopa, with high iron-induced lipid peroxidation inhibitory activity, due to strong iron (III) binding, 5-S-glutathionylpiceatannol a most effective inhibitor of nitrosation processes, and 5-S-lipoylhydroxytyrosol, and its polysulfides that proved valuable oxidative-stress protective agents in various cellular models. Different methodologies have been used for evaluation of the antioxidant power of these compounds against the parent compounds. These include kinetics of inhibition of lipid peroxidation alkylperoxyl radicals, common chemical assays of radical scavenging, inhibition of the OH• mediated hydroxylation/oxidation of model systems, ferric- or copper-reducing power, scavenging of nitrosating species. In addition, computational methods allowed researchers to determine the Bond Dissociation Enthalpy values of the OH groups of chalcogen modified phenolics and predict the best performing derivative. Finally, the activity of Se and Te containing compounds as mimic of glutathione peroxidase has been evaluated, together with other biological activities including anticancer action and (neuro)protective effects in various cellular models. These and other achievements are discussed and rationalized to guide future development in the field.

Site-specific halloysite functionalization by polydopamine: A new synthetic route for potential near infrared-activated delivery system.

Halloysite nanotubes (HNTs) represent a versatile core structure for the design of functional nanosystems of biomedical interest. However, the development of selective methodologies for the site-controlled functionalization of the nanotubes at specific sites is not an easy task. This study aims to accomplish a procedure for the site-selective/specific, "pin-point", functionalization of HNTs with polydopamine (HNTs@PDA). This goal was achieved, at pH 6.5, by exploiting the basicity of ZnO nanoparticles anchored on the HNTs external surface (HNTs@ZnO) to induce a punctual polydopamine polymerization and coating. The morphology and the chemical composition of the nanomaterial was demonstrated by several techniques. Turbidimetric analysis showed that PDA coating affected the aqueous stability of HNTs@PDA compared to both HNTs@ZnO and HNTs. Notably, hyperthermia studies revealed that the nanomaterial induced a local thermic rise, up to 50 °C, under near-infrared (NIR) irradiation. Furthermore, secondary functionalization of HNTs@PDA by selective grafting of biotin onto the PDA coating followed by avidin binding was also accomplished.