Presentación inusual de infección por SARS-CoV-2 simulando púrpura de Schönlein Henoch (vasculitis por inmunoglobulina A)

La vasculitis por inmunoglobulina A, anteriormente llamada púrpura Schönlein Henoch (VIgA/PSH), es la vasculitis sistémica más frecuente en la infancia. El desencadenante más común es una infección previa del tracto respiratorio superior. Se caracteriza por púrpura palpable no trombocitopénica con artralgias y/o artritis, afectación gastrointestinal y compromiso renal. SARS-CoV-2 es un virus ARN que causa la enfermedad COVID-19. Afecta frecuentemente el sistema respiratorio con presentaciones que varían desde una rinitis hasta condiciones severas como síndrome de distress respiratorio, shock séptico o síndrome de in amación multisistémica (multi-system in ammation syndrome, MIS). Se describe el caso de un niño de 5 años de edad con clínica de VIgA/PSH como forma inicial de presentación y diagnóstico posterior de infección por SARS-CoV-2, derivado al hospital de mayor complejidad, con encefalopatía hipertensiva que presentó evolución favorable y restitución completa del cuadro clínico

Effects of a new nanocomposite system on Human Gingival Fibroblasts/Streptococcus mitis co-culture

In the broad field of biomaterials, Bisphenol A glycidylmethacrylate (BisGMA)/triethyleneglycol dimethacrylate (TEGDMA) thermosets are frequently used for dental restoration (Lehtinen et al 2008), but infections due to bacterial adhesion remain the main reason of dental devices failure. In order to avoid biofilm formation on the components used for restoration and to reduce cytotoxicity against eukaryotic cells, a new material with antimicrobial properties was developed. Indeed, silver nanoparticles (n-Ag), which have well-known antimicrobial properties, were stabilized with a polyelectrolyte solution-Chitlac (lactose-modified chitosan) and was used to coating methacrylic thermosets (Travan et al, 2011). This study was aimed at evaluating the in vitro biological response of human gingival fibroblasts (HGFs)/Streptococcus mitis co-colture to this nanocomposite system. HGFs were obtained from fragments of healthy marginal gingival tissue, co-cultured with the clinical strain of S. mitis and treated for 24 -48 h with thermosets (uncoated or coated with Chitlac or Chitlac n-Ag). Cytotoxicity was evaluated by LDH assay; cell morphology and adhesion were verified by means of SEM and optical microscopy; cell migration was studied by a modified Boyden chamber and finally IL-6 and PGE2 secretion were detected by ELISA assays. In vitro results showed that in our co-culture model, which mimics the microenvironment of the oral cavity, the nanocomposite material does not exert cytotoxic effect towards HGFs that are able to adhere and migrate. The secretion of IL-6 is significant, but PGE2 production is minimal suggesting that IL-6 production is not related to an inflammatory response. Basing on its good biocompatibility we suggest this new tool useful for the realization of dental devices

Respiratory failure and death in vulnerable premature children with lower respiratory tract illness

Background. Efforts to better understand the risk factors associated with respiratory failure (RF) and fatal lower respiratory tract infection (LRTI) in premature children in developing countries are necessary to elaborate evidenced-based preventive interventions. We aim to characterize the burden of respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) LRTI in premature children and determine risk factors for RF and fatal illness in a vulnerable population. Methods. This is a prospective, population-based, cross-sectional study. Subjects with severe LRTI were enrolled during respiratory season. Risk factors for RF and death in premature infants were investigated. Results. A total of 664 premature children participated. Infant's hospitalization rate due to LRTI was 82.6/1000 (95% confidence interval [CI], 68.6-96.7/1000). Infant's RSV and hMPV rates were 40.9/1000 (95% CI, 36.3-45.6/1000) and 6.6/1000 (95% CI, 3.9- 9.2/1000), respectively. The RF rate was 8.2/1000 (95% CI, 4.9-11.5/1000). The LRTI mortality was 2.2/1000 (95% CI, 0.7-3.7/1000); for RSV, the rate was 0.8/1000 (95% CI, 0-1.7/1000) with a case-fatality ratio of 1.8%. Never breastfeeding, malnutrition, younger than 6 months, congenital heart disease, and lower hematocrit were risk factors for RF. Experiencing pneumonia, pneumothorax, sepsis, or apnea were clinical determinants of poor outcomes. Conclusions. Premature children under 2 years old in vulnerable environments experience RF and death more often than term counterparts. Modifiable risk factors associated with poor outcomes should prompt evidence-based interventions.Fil: Ofman, Gaston. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Pradarelli, Brad. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Caballero, Mauricio Tomás. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bianchi, Alejandra. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Grimaldi, Luciano Alva. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Sancilio, Andrea. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal de Agudos Evita; ArgentinaFil: Duenas, Karina. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal de Agudos Evita; ArgentinaFil: Rodriguez, Andrea. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Ferrero, Fernando. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Ferretti, Adrian. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Coviello, Silvina Andrea. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferolla, Fausto Martín. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acosta, Patricio Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Bergel, Eduardo. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Libster, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Polack, Fernando Pedro. Fundacion de Endocrinologia Infantil.; Argentin

Effect of Chitlac-nAg on Streptococcus mitis internalization into human gingival fibroblasts

The surfaces of the oral cavity are always exposed to a broad variety of microor- ganisms able to form biofilms (Filoche et al, 2010) characterized by microbial com- munities that are organized as a network of cell-to-cell interactions. Streptococci are the predominant bacterial population of the oral environment and S.mitis in particular is the first colonizer of the oral biofilm (Di Giulio et al, 2013). Silver-based medical products have been proven to be effective in retarding and preventing bacterial growth. In order to prevent silver nanoparticles aggregation, a lactose-modified chitosan has been set up and resulted effective in stabilizing colloidal solution of nanoparticles (Chitlac-nAg) (Travan et al, 2009). Since many bacteria are able to internalize into eukaryotic cells, in our study we have investigated both the intracellular signaling governing S. mitis internalization into HGFs and the biological effect of ChitlacnAg on eukaryotic and prokaryotic cells in a co-culture model system. The internalization of S. mitis into HGFs is due to F-actin cytoskeleton reorganization and reduced expression within the cell. Immunofluorescence shows actin polymerization at invasion sites along with vinculin increased expression and spot organization. Vinculin is an adaptor protein that regulates the adhesion of integrin receptors to actin cytoskeleton. In presence of S. mitis an increment of integrin β1 and FAK expression, responsible for the entrance of the microorganism in HGFs is consistent, as revealed by electron microscopy analysis. This adhesion and uptake proteins profile is the same in the presence of saliva as well as bacteria uptake. When Chitlac-nAg is administred to cell culture the expression of all four proteins decreases and Ag nano- particles are recognized within the cells. Further, in presence of Ag nanoparticles the low amount of FAK is almost localized at nuclear level. In presence of Ag and S.mitis, the expression of all four proteins is increased, with respect to control, and F-actin cytoskeleton rearranged, while a raised number of bacteria is shown. This effect is mit- igated by the presence of saliva in cell culture, which probably prevents bacteria entry into the cell. These results let us hypothesize that Chitlac-nAg, developing its bacteri- cidal action could represent a good component of tooth paste and mouthwash

Escape from cell death through authophagy in Human Gingival Fibroblast/Streptococcus mitis co-culture treated with Chitlac n-Ag

Since ancient times, silver has been extensively used to control infections. Silver based medical products have been proved to be effective in retarding and preventing bacterial infections (Chen et al., 2007). In order to prevent silver nanoparticles aggregation a lactose-modified chitosan was shown to be effective in stabilizing colloidal solutions of silver nanoparticles: “Chitlac-nAg” (Travan et al., 2009). Silver ions and nanoparticle are capable to destroy the bacterial cell wall by reacting with sulfhydryl groups on membrane proteins (Kruszewski et al., 2003). Since the cells are capable of internalizing nanoparticles there is the risk of a massive uptake by eukaryotic cells, which eventually leads to their death through oxidative DNA damage (Li et al. 2013) In the present work we investigated the effects of Chitlac-nAg on primary human gingival fibroblast (HGFs) co-cultured with Streptococcus mitis in the presence of saliva. HGFs were obtained from fragments of healty marginal gingival tissue, co-cultured with the clinical strain of S. mitis and treated for 24-48h with Chitlac or Chitlac-nAg. Cytotoxicity evaluated by LDH assay showed an increment in LDH release in co-culture in the presence of Chitlac n-Ag and saliva. Oxidative stress detected by means of Reactive Oxygen Species formation highlighted an early ROS presence in samples with Chitlac-nAg and saliva, but this value was similar to control after 48h; apoptotic and necrotic cells were detected by means of Annexin V/PI showing an increase in cell death in HGFs treated with Ag and saliva after 24h, and returned to basal levels after 48h; the uptake of nanoparticles by cells was determined by optical and electronic microscopy revealing the Ag uptake in vesicles. The presence of lysosomes and autophagosomes was verified by Lysotracker and by LC3 respectively. In vitro results showed that in our co-culture model, which mimics the microenvironment of the oral cavity, chitlac n-Ag does not exert cytotoxic effect towards HGFs that are able to execute a homeostasis mechanism through autophagy promoting cell survival

Spare Parts from Discarded Materials: Fetal Annexes in Regenerative Medicine

One of the main aims in regenerative medicine is to find stem cells that are easy to obtain and are safe and efficient in either an autologous or allogenic host when transplanted. This review provides an overview of the potential use of the fetal annexes in regenerative medicine: we described the formation of the annexes, their immunological features, the new advances in the phenotypical characterization of fetal annexes-derived stem cells, the progressions obtained in the analysis of both their differentiative potential and their secretoma, and finally, the potential use of decellularized fetal membranes. Normally discarded as medical waste, the umbilical cord and perinatal tissue not only represent a rich source of stem cells but can also be used as a scaffold for regenerative medicine, providing a suitable environment for the growth and differentiation of stem cells

The Effect of a Silver Nanoparticle Polysaccharide System on Streptococcal and Saliva-Derived Biofilms

In this work, we studied the antimicrobial properties of a nanocomposite system based on a lactose-substituted chitosan and silver nanoparticles: Chitlac-nAg. Twofold serial dilutions of the colloidal Chitlac-nAg solution were both tested on Streptococcus mitis, Streptococcus mutans, and Streptococcus oralis planktonic phase and biofilm growth mode as well as on saliva samples. The minimum inhibitory and bactericidal concentrations of Chitlac-nAg were evaluated together with its effect on sessile cell viability, as well as both on biofilm formation and on preformed biofilm. In respect to the planktonic bacteria, Chitlac-nAg showed an inhibitory/bactericidal effect against all streptococcal strains at 0.1% (v/v), except for S. mitis ATCC 6249 that was inhibited at one step less. On preformed biofilm, Chitlac-nAg at a value of 0.2%, was able to inhibit the bacterial growth on the supernatant phase as well as on the mature biofilm. For S. mitis ATCC 6249, the biofilm inhibitory concentration of Chitlac-nAg was 0.1%. At sub-inhibitory concentrations, the Streptococcal strains adhesion capability on a polystyrene surface showed a general reduction following a concentration-dependent-way; a similar effect was obtained for the metabolic biofilm activity. From these results, Chitlac-nAg seems to be a promising antibacterial and antibiofilm agent able to hinder plaque formation

Biological Responses of Human Gingival Fibroblasts (HGFs) in an Innovative Co-Culture Model with Streptococcus mitis to Thermosets Coated with a Silver Polysaccharide Antimicrobial System

This study sought to evaluate the in vitro biological response of human gingival fibroblasts (HGFs) co-coltured with Streptococcus mitis to bisphenol A glycidylmethacrylate/triethylene glycol dimethacrylate (BisGMA/TEGDMA) thermosets coated with Chitlac-nAg, a nanocomposite system with antimicrobial properties. To avoid bacterial adhesion to dental devices and to reduce cytotoxicity against eukaryotic cells, we coated BisGMA/TEGDMA methacrylic thermosets with a new material, Chitlac-nAg, formed by stabilizing silver nanoparticles, which have well-known antimicrobial properties, with a polyelectrolyte solution containing Chitlac. Cytotoxicity, cell morphology, cell migration and inflammatory interleukine-6 (IL- 6) and prostaglandin E2 (PGE2) secretion were evaluated. Our results showed that the cytotoxicity exerted on HGFs by our nanocomposite material was absent in our co-culture model, where fibroblasts are able to adhere and migrate. After 24 h thermosets coated with Chitlac as well as those coated with Chitlac-nAg exerted a minimal cytotoxic effect on HGFs, while after 48 h LDH release rises up 20%. Moreover the presence of S. mitis reduced this release in a greater amount with ChitlacnAg coated thermosets. The secretion of IL-6 was significant in both Chitlac and Chitlac-nAg coated thermosets, but PGE2 production was minimal, suggesting that the IL-6 production was not related to an inflammatory response. Co-culture and the addiction of saliva did not influence IL-6 and PGE2 secretion. Data obtained in the present work suggest that Chitlac n- Ag coated thermosets could significantly improve the success rates of restorative dentistry, since they limit bacterial adhesion and are not toxic to HGFs

Biological responses of human gingival fibroblasts (HGFs) in an innovative co-culture model with Streptococcus mitis to thermosets coated with a silver polysaccharide antimicrobial system.

This study sought to evaluate the in vitro biological response of human gingival fibroblasts (HGFs) co-coltured with Streptococcus mitis to bisphenol A glycidylmethacrylate/triethylene glycol dimethacrylate (BisGMA/TEGDMA) thermosets coated with Chitlac-nAg, a nanocomposite system with antimicrobial properties. To avoid bacterial adhesion to dental devices and to reduce cytotoxicity against eukaryotic cells, we coated BisGMA/TEGDMA methacrylic thermosets with a new material, Chitlac-nAg, formed by stabilizing silver nanoparticles, which have well-known antimicrobial properties, with a polyelectrolyte solution containing Chitlac. Cytotoxicity, cell morphology, cell migration and inflammatory interleukine-6 (IL-6) and prostaglandin E2 (PGE2) secretion were evaluated. Our results showed that the cytotoxicity exerted on HGFs by our nanocomposite material was absent in our co-culture model, where fibroblasts are able to adhere and migrate. After 24 h thermosets coated with Chitlac as well as those coated with Chitlac-nAg exerted a minimal cytotoxic effect on HGFs, while after 48 h LDH release rises up 20%. Moreover the presence of S. mitis reduced this release in a greater amount with Chitlac-nAg coated thermosets. The secretion of IL-6 was significant in both Chitlac and Chitlac-nAg coated thermosets, but PGE2 production was minimal, suggesting that the IL-6 production was not related to an inflammatory response. Co-culture and the addiction of saliva did not influence IL-6 and PGE2 secretion. Data obtained in the present work suggest that Chitlac n-Ag coated thermosets could significantly improve the success rates of restorative dentistry, since they limit bacterial adhesion and are not toxic to HGFs