Using HScore for Evaluation of Hemophagocytosis in Multisystem Inflammatory Syndrome Associated with COVID-19 in Children.

Hemophagocytic syndrome is a key point in the pathogenesis of severe forms of multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C). The factors associated with hemophagocytosis in patients with MIS-C were assessed in the present study of 94 boys and 64 girls ranging in age from 4 months to 17 years, each of whose HScore was calculated. In accordance with a previous analysis, patients with HScore ≤ 91 (n = 79) and HScore > 91 (n = 79) were compared. Patients with HScore > 91 had a higher frequency of symptoms such as cervical lymphadenopathy, dry cracked lips, bright mucous, erythema/swelling of hands and feet, peeling of fingers, edematous syndrome, hepatomegaly, splenomegaly, and hypotension/shock. They also had a higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and D-dimer levels, and a tendency to anemia, thrombocytopenia, and hypofibrinogenemia. They more often needed acetylsalicylic acid and biological treatment and were admitted to ICU in 70.9% of cases. Conclusion: The following signs of severe MIS-C were associated with HScore > 91: myocardial involvement, pericarditis, hypotension/shock, and ICU admission.

Determination of Risk Factors for Severe Life-Threatening Course of Multisystem Inflammatory Syndrome Associated with COVID-19 in Children.

Multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C) is a life-threatening condition that often requires intensive care unit (ICU) admission. The aim of this study was to determine risk factors for severe/life-threatening course of MIS-C. The study included 166 patients (99 boys, 67 girls) aged 4 months-17 years (median 8.2 years). The criterion of severity was the fact of ICU admission. To conduct a comparative analysis, MIS-C patients were divided into two groups: patients hospitalized in the ICU (n = 84, 50.6%) and those who did not need ICU admission (n = 82, 49.4%). Patients with a more severe course of MIS-C were significantly older. They had a higher frequency of signs such as rash, swelling, hepatomegaly, splenomegaly, and neurological and respiratory symptoms. Hypotension/shock and myocardial involvement were much more common in patients with severe MIS-C. These patients had a more significant increase in CRP, creatinine, troponin, and D-dimer levels. Additionally, the presence of macrophage activation syndrome was higher in patients admitted to the ICU. Conclusion: Nineteen predictors of severe course of MIS-C were found, out of which hepatomegaly, splenomegaly, D-dimer > 2568 ng/mL, troponin > 10 pg/mL were mainly associated with the probability of being classified as early predictors of severe MIS-C requiring ICU admission.

Rituximab Biosimilar BCD020 Shows Superior Efficacy above Conventional Non-Biologics Treatment in Pediatric Lupus Nephritis: The Data of Retrospective Cohort Study.

BACKGROUND: Pediatric lupus nephritis (LN) is one of the most serious manifestations of systemic lupus erythematosus (SLE) in children, determining the outcomes of the disease. There are no standardized treatment protocols for pediatric LN, and the role of biologics has not yet been conclusively defined. OBJECTIVES: analyze the safety and efficacy of rituximab biosimilar BCD020 in pediatric patients with lupus nephritis. METHODS: in a retrospective cohort study, the data from the case histories of 25 patients with LN (10 boys and 15 girls) with an onset age of 13 (9-16) years, who failed conventional non-biologic treatment or developed corticosteroid dependence/toxicity, were included. The diagnosis was made using Systemic Lupus International Collaborating Clinics (SLICC) classification criteria. Rituximab biosimilar BCD020 was prescribed in a dosage of 375 mg/m2 every week (2-4 infusions) with repeated courses every 6-12 months (2-4 infusions) according to disease activity, B-cell depletion, and IgG levels. The dynamics of clinical and laboratory data, the activity of the disease by SLEDAI, and corticosteroid doses were assessed at the onset and during the rituximab trial. RESULTS: The main patient's characteristics were: Pre-rituximab non-biologic conventional treatment included: cyclophosphamide 15 (60%), MMF 8 (32%), azathioprine 3 (12%), hydroxychloroquine 12 (48%), and pulse therapy of methylprednisolone followed by oral methylprednisolone 25 (100%). The time before rituximab was 7.0 (3.0-24.0) months, and the whole observation period was 7.0 (0; 24) months. The initial pre-rituximab treatment slightly reduced SLEDAI levels and the proportion of patients with LN. A significant reduction of SLEDAI, the anti-dsDNA level, proteinuria, hematuria, C4 complement, ESR, and the median corticosteroid dose by 80% from the initial value, as well as the proportion of patients without corticosteroids, was observed after rituximab administration. Two deaths were observed due to catastrophic SLE with macrophage activation syndrome, accompanied by a severe infection (invasive aspergillosis, n = 2). Three patients developed serious adverse events: pneumonia (n = 2), transient agranulocytosis (n = 1) after the third rituximab infusion, and meningitis, caused by Listeria monocytosis, after the first rituximab infusion. Eight patients received antibacterial treatment for different respiratory infections without hospital admissions. CONCLUSIONS: Rituximab biosimilar BCD020 showed effectiveness in LN, whereas previous non-biologic treatment was insufficiently effective. Randomized controlled trials are required to evaluate the efficacy and safety of rituximab and evaluate the benefits when compared with conventional SLE treatment.

Mucosal immunity in health care workers' respiratory tracts in the post-COVID-19 period.

Coronavirus disease (COVID-19) has generated interest in the assessment of systemic immune status, but existing knowledge about mucosal immunity is clearly insufficient to understand the full pathogenetic mechanisms of the disease. The aim of this study was to evaluate the long-term effects of novel coronavirus infection on mucosal immunity in the postinfection period among health care workers (HCWs). A total of 180 health care workers with and without a history of COVID-19 who ranged in age from 18 to 65 years were enrolled in this one-stage, cross-sectional study. The study subjects completed the 36-Item Short Form (36) Health Survey (SF-36) and the Fatigue Assessment Scale. Secretory immunoglobulin A (sIgA) and total immunoglobulin G (IgG) levels were quantified in saliva samples, induced sputum samples, and nasopharyngeal and oropharyngeal scrapings by an enzyme-linked immunosorbent assay. Specific anti-SARS-CoV-2 IgG antibodies were quantified in serum samples by chemiluminescence immunoassay. Analysis of the questionnaire data showed that all HCWs with a history of COVID-19 reported health problems that limited their daily activities and negative changes in their emotional health three months after the disease, regardless of its severity. The following shifts were detected in the adaptive arm of the immune response in different mucosal compartments. Among subjects who had severe or moderate-to-severe COVID-19, salivary sIgA levels were significantly higher than those in the control group (p < 0.05 and p < 0.005, respectively). Compared to the subjects in the control group, all subjects with prior COVID-19 had significantly higher levels of total IgG in induced sputum. In the group of patients who had had severe infection, total IgG in saliva was also higher (p < 0.05). A direct statistically significant correlation was also detected between the levels of total IgG in all studied samples and the levels of specific IgG antibodies against SARS-CoV-2 in the serum. A significant correlation was observed between total IgG levels and the parameters of physical and social activities, mental health, and fatigue levels. Our study demonstrated long-term changes in the humoral mucosal immune response, which were most pronounced in health care workers with a history of severe or moderate-to-severe COVID-19, and an association of these changes with certain clinical signs of post-COVID-19 syndrome.

Heart Involvement in Multisystem Inflammatory Syndrome, Associated With COVID-19 in Children: The Retrospective Multicenter Cohort Data.

Objectives: Heart involvement in multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C) is a new challenging problem, requiring fast and reliable diagnostics and appropriate treatment. The aim of this study is to describe heart involvement in patients with MIS-C. Study Design: In this retrospective, multicenter cohort study, data of 122 patients were included. All patients met WHO and CDC criteria of MIS-C. Results: Various types of heart involvement in MIS-C patients were observed. Patients with solely coronary artery lesions (CAL, n = 10, 8.2%) had typical features of Kawasaki disease: younger age, thrombocytosis and normal ferritin level, without giant CA aneurysms, thrombosis, myocardial infarction, shock, and ICU admission. Patients with solely myocardial involvement (MI, n = 30, 24.6%) had an older onset age, elevated ferritin, LDH, the highest D-dimer, H score, and thrombocytopenia level. The following clinical signs were associated with MI: gastrointestinal and central nervous system disorder, sore throat, swelling face, splenomegaly, shock, and treatment in the intensive care unit required. Patients with a combination of CAL and MI (n = 10, 8.2%) had symptoms similar to patients with solely MI, except for impressive thrombocytopenia. Shock and ICU admission were found in 34.7% of patients without heart involvement (n = 72, 59%). One major criterion [troponin > 32 pg/ml (52 points)] or at least two minor criteria [face swelling (32 points) and D-Dimer > 1,300 ng/ml (29 points)] were associated with MI (>32 points) with a sensitivity of 67.5% and a specificity of 88.9%. Conclusion: The above-suggested criteria can be added to routine diagnostic procedures to confirm MI in MIS-C patients.

Impedimetric transducers based on interdigitated electrode arrays for bacterial detection - A review.

Application of the impedance spectroscopy technique to detection of bacteria has advanced considerably over the last decade. This is reflected by the large amount of publications focused on basic research and applications of impedance biosensors. Employment of modern technologies to significantly reduce dimension of impedimetric devices enable on-chip integration of interdigitated electrode arrays for low-cost and easy-to-use sensors. This review is focused on publications dealing with interdigitated electrodes as a transducer unit and different bacteria detection systems using these devices. The first part of the review deals with the impedance technique principles, paying special attention to the use of interdigitated electrodes, while the main part of this work is focused on applications ranging from bacterial growth monitoring to label-free specific bacteria detection.

Calcium-selective electrodes based on photo-cured polyurethane-acrylate membranes covalently attached to methacrylate functionalized poly(3,4-ethylenedioxythiophene) as solid-contact.

We report here the fabrication of solid-contact calcium-selective electrodes (Ca2+-SCISEs) made of a polyurethane acrylate ion-selective membrane (ISM) that was covalently attached to the underlying ion-to-electron transducer (solid-contact). Methacrylate-functionalized poly(3,4-ethylenedioxythiophene) (Meth-PEDOT) and Meth-PEDOT films containing either multiwalled carbon nanotubes (MWCNT) or carboxylated MWCNT (cMWCNT) were used as solid contacts. The solid contacts were deposited by drop-casting on screen-printed electrodes and characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and potentiometry. Covalent binding between the solid contact and the ISM was obtained via photopolymerization in order to increase the robustness of the Ca2+-SCISEs. The performance of the Ca2+-SCISEs was studied by measuring their potentiometric response and their sensitivity to light, oxygen and carbon dioxide. Meth-PEDOT was found to be a promising solid-contact material to develop low-cost and easy to prepare ISEs.

Solid contact ion sensor with conducting polymer layer copolymerized with the ion-selective membrane for determination of calcium in blood serum.

A new solid contact ion selective electrode with intermediate conducting polymer (CP) layer formed by electropolymerization on a gold electrode of a bifunctional monomer, n-phenyl-ethylenediamine-methacrylamide (NPEDMA), which contains a methacrylamide group attached to aniline, is presented. The conducting polymer was studied by means of optical spectroscopy, cyclic voltammetry and potentiometric measurements. Ca2+-ion-selective membrane based on acrylated urethane polymer was shown to co-polymerize with the CP forming highly adhesive boundary that prevents formation of water layers between the CP and membrane, thus enhancing the stability and life-time of the sensor. The designed ion-selective electrode was successfully used for determination of total calcium ion concentration in blood serum samples.

Impedimetric antimicrobial peptide-based sensor for the early detection of periodontopathogenic bacteria.

Peri-implantitis, an inflammation caused by biofilm formation, constitutes a major cause of implant failure in dentistry. Thus, the detection of bacteria at the early steps of biofilm growth represents a powerful strategy to prevent implant-related infections. In this regard, antimicrobial peptides (AMPs) can be used as effective biological recognition elements to selectively detect the presence of bacteria. Thus, the aim of the present study was to combine the use of miniaturized and integrated impedimetric transducers and AMPs to obtain biosensors with high sensitivity to monitor bacterial colonization. Streptococcus sanguinis, which is one of the most prevalent strains in the onset of periodontal diseases, was used as a model of oral bacteria. To this end, a potent AMP derived from human lactoferrin was synthesized and covalently immobilized on interdigitated electrode arrays (IDEA). X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) were employed to optimize and characterize the method of immobilization. Noteworthy, the interaction of Streptococcus sanguinis with AMP-coated sensors provoked significant changes in the impedance spectra, which were univocally associated with the presence of bacteria, proving the feasibility of our method. In this regard, the developed biosensor permits to detect the presence of bacteria at concentrations starting from 10(1) colony forming units (CFU)mL(-1) in KCl and from 10(2) CFUmL(-1) in artificial saliva. Moreover, the system was devoid of cytotoxicity for human fibroblasts. These results indicate that the proposed approach can be effective in the detection of initial stages of biofilm formation, and may be useful in the early prevention and treatment of peri-implantitis.

Miniaturized metal oxide pH sensors for bacteria detection.

It is well known that the metabolic activity of some microorganisms results in changes of pH of the culture medium, a phenomenon that can be used for detection and quantification of bacteria. However, conventional glass electrodes that are commonly used for pH measurements are bulky, fragile and expensive, which hinders their application in miniaturized systems and encouraged to the search for alternatives. In this work, two types of metal oxide pH sensors have been tested to detect the metabolic activity of the bacterium Escherichia coli (E. coli). These pH sensors were produced on silicon chips with platinum metal contacts, onto which thin layers of IrOx or Ta2O5 were incorporated by two different methods (electrodeposition and e-beam sputtering, respectively). In order to facilitate measurement in small sample volumes, an Ag/AgCl pseudo-reference was also screen-printed in the chip and was assayed in parallel to an external Ag/AgCl reference electrode. As it is shown, the developed sensors generated results indistinguishable from those provided by a conventional glass pH-electrode but could be operated in significantly smaller sample volumes. After optimization of the detection conditions, the metal oxide sensors are successfully applied for detection of increasing concentrations of viable E. coli, with detection of less than 10(3)cfu mL(-1) in undiluted culture medium in just 5h.

Response of a microcapillary impedimetric transducer to changes in surface conductance at liquid/solid interface.

A new device based on an interdigitated electrode array with electrode digits located at the bottom of microcapillaries is presented. Microcapillaries formed in silicon dioxide are 3 µm wide, 4 µm high and are open at the top, so that in contact with an electrolyte solution the AC current flows from one capillary to another and is significantly affected by changes in surface conductivity at the SiO2/electrolyte interface. The effect of charged polyelectrolyte layers electrostatically assembled on the sensor surface on the surface conductivity in solutions with different KCl concentration is presented. From measured impedance spectra polyelectrolyte adsorption curve is determined. The device is shown to be useful for real time adsorption kinetics monitoring.

An impedimetric chemical sensor for determination of detergents residues.

A new impedimetric sensor based on an interdigitated electrode array with electrode digits located at the bottom of microcapillaries formed in silicon dioxide is presented. Microcapillaries are opened at the top, so that in contact with an electrolyte solution the ac current flows close to the surface of the capillary wall from one electrode to another and is significantly affected by changes in the surface conductance at the SiO2/electrolyte interface. Adsorption of detergents on the sensor surface affects the charge distribution in the electrical double layer and thus the surface conductance. These changes are registered by measuring impedance. Effect of surface adsorption of ionic and non-ionic surfactants on the sensor impedance is studied. The sensor is shown to be able to measure commercial detergents residues in a tap water starting from 5 ppm even in solutions with high electrolyte conductivity.

Thick-film voltammetric pH-sensors with internal indicator and reference species.

The following paper describes the development of a screen-printed voltammetric pH-sensor based on graphite electrodes incorporating both internal indicator (i.e., phenanthraquinone) and reference species (i.e., dimethylferrocene). The key advantages of this type of system stem from its simplicity, low cost and ease of fabrication. More importantly, as opposed to conventional voltammetric systems where the height of the voltammetric peaks is taken into account to quantify the amount of a species of interest, here, the difference between the peak potential of the indicator species and the peak potential of the reference species is used. Thus, this measurement principle makes the electrochemical system presented here less dependent on the potential of the reference electrode (RE), as is often the case in other electrochemical systems. The developed system displays very promising performances, with a reproducible Super Nernstian response to pH changes and a lifetime of at least nine days.

The influence of CO(2) on ISFETs with polymer membranes and characterization of a carbonate ion sensor.

The influence of CO(2) and acetic acid on the response of ISFET sensors with PVC and photocured polyurethane polymer membranes with valinomycin as an ionophore was assessed. Experimental results show that the presence of these compounds has no effect on sensors parameters even after prolonged soaking in a water solution. Using a photocured polyurethane polymer as an ion-selective membrane matrix for an ISFET, a carbonate ion sensor was developed with hexyl-p-trifluoroacetylbenzoate (HE) as an ionophore. Effect of cationic and anionic lipophilic additives on the sensors response was studied. Sensors with the optimized membrane composition based on HE (7.9%, w/w) and tridodecylmethylammonium chloride (5.7%, w/w) show sensitivity of 27-30mV per decade of carbonate ion concentration, sufficient selectivity in front of chloride ions, and a lifetime of 3-5 months.

Photocurable pH-sensitive membrane for ion-selective field effect transistors.

H(+)-ion sensitive ISFETs with photocured polyurethane-based polymer membranes with three different neutral carrier ionophores and four different plasticizers have been studied in 0.05 M TRIS-HCl solutions and in background solutions containing 140 mM of Na(+) ions. The optimised membrane composition showing the best selectivity contains 2.2-2.5 wt.% of the ionophore (tridodecylamine), 36-41 wt.% of a plasticizer, and only 10 mol% of a lipophilic salt KTClPhB. The optimal ionophore/lipophilic salt ratio obtained in this work differs significantly from theoretically recommended for pH-sensitive ion-selective membranes. It is assumed that this is due to the participation of the ionophore (tertiary amine) and lipophilic additives (tetrachlorophenylborate anion) in additional photochemical reactions occurring during irradiation of the membrane matrix. Sensors with the optimised membrane composition showed sufficient sensor selectivity in front of sodium ions for clinical and biomedical applications and the lifetime of more than 3 months.

Integrated multi-sensor chip with photocured polymer membranes containing copolymerized plasticizer for direct pH, potassium, sodium and chloride ions determination in blood serum.

An analytical system based on a sensor array with ion-selective field effect transistors (ISFETs) monolithically integrated in one chip covered with photocured polymer membranes containing copolymerized plasticizer and a sequential injection analysis (SIA) is shown to offer an automation of the analysis of blood serum components. For sequential injection system a custom made dual channel flow cell for the sensor array was developed. Optimisation of ion-sensitive membrane characteristics and calibration solution compositions were carried out. The system was used to analyze sodium, potassium, chloride ion contents in blood serum samples. The precision of the ion determination in samples was typical for potentiometric method with standard deviation of about 3-5%.

Photocurable polymers for ion selective field effect transistors. 20 years of applications.

Application of photocurable polymers for encapsulation of ion selective field effect transistors (ISFET) and for membrane formation in chemical sensitive field effect transistors (ChemFET) during the last 20 years is discussed. From a technological point of view these materials are quite interesting because they allow the use of standard photo-lithographic processes, which reduces significantly the time required for sensor encapsulation and membrane deposition and the amount of manual work required for this, all items of importance for sensor mass production. Problems associated with the application of this kind of polymers in sensors are analysed and estimation of future trends in this field of research are presented.

Three-dimensional interdigitated electrode array as a transducer for label-free biosensors.

A new transducer for biosensor applications has been developed based on a three-dimensional interdigitated electrode array (IDEA) with electrode digits separated by an insulating barrier. Binding of molecules to a chemically modified surface of the transducer induces important changes in conductivity between the electrodes. Three-dimensional sensor shows considerable improvement compared with a standard planar IDEA design. The potential of the developed device as a sensor transducer to detect immunochemical and enzymatic reactions, as well as DNA hybridization events is demonstrated. The immunosensor allows direct detection of the antibiotic sulfapyridine and shows the IC(50) parameter value of 5.6 microgL(-1) in a buffer. Immunochemical determination occurs under competitive configurations and without the use of any label. Each modified sensor is of a single use. Nevertheless, biochemical reagents can be easily cleaned off the sensor surface for its reuse. Layer-by-layer method of used to deposit polyethyleneimine and glucose oxidase showed that the sensor is also highly effective for detecting single and multilayered molecular assemblies.

Stage-specific changes in gene expression in acutely isolated mouse CNS progenitor cells.

Neural progenitor cells can be derived from a variety of developmental stages when they are preferentially proliferating, undergoing neurogenesis or undergoing gliogenesis. We used FACS sorting and the LeX surface marker to enrich neural progenitor cells from different embryonic stages and adult and compared their gene expression profiles using Affymetrix Microarrays. Our results show that, while there are common genes expressed in the progenitor cell population from all stages, there are also significant differences in gene expression patterns that correlate with stage-related behaviors. These data indicate that progenitor cells change during development and that adult and embryonic neural progenitor cells are intrinsically different.

Endothelial cells stimulate self-renewal and expand neurogenesis of neural stem cells.

Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells. We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production. Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro. Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes 1 to promote self-renewal. These findings identify endothelial cells as a critical component of the neural stem cell niche.