Hydroxychloroquine in the treatment of COVID-19 disease: a systematic review and meta-analysis

BACKGROUND Given the urgency of finding a specific treatment for coronavirus disease 2019 (COVID-19), several approaches have been carried out, including the use of chloroquine (CQ) and hydroxychloroquine (HCQ). This study was aimed to systematically evaluate the available evidence on the effectiveness of HCQ in the treatment of COVID-19 disease. METHODS We searched 3 databases (PubMed, Google Scholar, and ClinicalTrials) until May 31, 2020 for clinical studies in patients diagnosed with COVID-19 comparing conventional treatment with and without HCQ combined with or without azithromycin. The risk of bias assessment and quality evaluation was carried out according to the Cochrane recommendations. RESULTS 5 articles (1 randomized clinical trial [RCT], 1 non-RCT, and 3 cohort studies) were included. The main outcome measure in 2 articles was the virological conversion determined by reverse transcription-polymerase chain reaction; however, the findings of both studies were contrary. The main objective of the other studies was to determine the effects of HCQ on COVID-19 mortality, and the studies showed similar results. In general, the studies showed methodological limitations, risk of bias, and variable quality. A meta-analysis from 2,041 patients showed the odds ratio of mortality for patients having HCQ and standard care was 1.38 (95% CI 0.93–2.04). CONCLUSIONS Considering the limited data available and the very low-to-moderate quality of the studies included in this systematic review, the evidence suggests that the HCQ administration does not decrease the risk of death from COVID-19

Synthesis, characterization and antibacterial activity of copper, nickel and bimetallic Cu–Ni nanoparticles for potential use in dental materials

AbstractThe antibacterial effect is a desirable property in dental materials. Development of simple methods for the preparation of nanosized metal particles has attracted significant attention because of their future applications due to unusual size-dependent antibacterial properties. Copper (Cu), Nickel (Ni) and bimetallic Cu–Ni nanoparticles were prepared by a simple chemical method and their antibacterial activity was tested against the widely used standard human pathogens Staphylococcus aureus (gram-negative) and Escherichia coli (gram-positive). Additionally, these nanoparticles were tested against the dental pathogen Streptococcus mutans. Our results are promising for potential use in dental materials science

Ceramic and Composite Polishing Systems for Milled Lithium Disilicate Restorative Materials: A 2D and 3D Comparative In Vitro Study.

Purpose: This study aims to evaluate the effectiveness of two ceramic and two composite polishing systems for a novel chairside computer-aided design/computer-aided manufacturing (CAD/CAM) lithium disilicate ceramic with three-dimensional and two-dimensional microscopy images. This ceramic material can be used for implant-supported or tooth-borne single-unit prostheses. Materials and Methods: Sixty flat samples of novel chairside CAD/CAM reinforced lithium disilicate ceramic (Amber Mill, Hass Bio) were divided into five groups (n = 15/group) and treated as follows: Group 1 (NoP), no polished treatment; group 2 (CeDi), polished with ceramic Dialite LD (Brasseler USA); group 3, (CeOp) polished with ceramic OptraFine (Ivoclar Vivadent); group 4, (CoDi) polished with composite DiaComp (Brasseler USA), and group 5 (CoAs), polished with composite Astropol (Ivoclar Vivadent). The polished ceramic surface topography was observed and measured with three-dimensional and two-dimensional images. Results: All polishing systems significantly reduced the surface roughness compared with the non-polished control group (Sa 1.15 μm). Group 2 (CeDi) provided the smoothest surface arithmetical mean eight with 0.32 μm, followed by group 3 (CeOp) with 0.34 μm. Group 5 (CoAs) with 0.52 μm provided the smoothest surface among the composite polishing kits. Group 4 (CoDi) with 0.66 μm provided the least smooth surface among all polishing systems tested. Conclusions: Despite the effectiveness of ceramic polishing systems being superior to composite polishing systems of the CAD/CAM lithium disilicate restorative material, both polishing systems significantly improved the smoothness

Synthesis, Characterization, and Catalytic Activity of Platinum Nanoparticles on Bovine-Bone Powder: A Novel Support

Pt nanoparticles supported on bovine-bone powder were obtained by a rather simple method consisting of immersing powder of bovine bone into a Pt+4 metal ion solution at room temperature and subsequent reduction by sodium borohydride.This method eliminates the calcination step of the usual catalyst preparation methods. The nanocomposite was characterized by transmission electron microscopy (TEM), which revealed uniformly dispersed platinum nanoparticles with average particle size of 2.2nm ± 0.6 nm.The XPS studies exhibited the presence of 63%Pt∘ and 37%PtO.The catalytic activity was tested in the hydrogenation of 2-butyne-1,4-diol.The nanocomposite shows good catalytic performance with nearly 100% conversion and 83% selectivity towards 2-butene-1,4-diol.CONACYT 26909

Shape Tuning of Magnetite Nanoparticles Obtained by Hydrothermal Synthesis: Effect of Temperature

Acknowledgments The authors acknowledge the Kleberg Advanced Microscopy Center (KAMiC) and NIH RCMI Nanotechnology and Human Health Core (Grant 5G12RR013646-12) at University of Texas at San Antonio for the support with electron microscopy. The authors gratefully acknowledge Dr. Elizande-Galindo and Dr. Farias Mancilla from UACJ for their technical support with magnetic measurements. This research was funded by UAEM Grant 3688/20147CIB and CONACYT Grant 280518. The authors thank the Cátedras-CONACYT program and the Facultad de Odontología, Universidad Autónoma Benito Juárez de Oaxaca, for their support. The authors also thank the financial support from DGAPA-UNAM: PAPIIT-IA205518 and PAPIME-PE208518.In this work, we present a simple and efficient method for pure phase magnetite (Fe3O4) nanoparticle synthesis. The phase structure, particle shape, and size of the samples were characterized by Raman spectroscopy (Rm), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDS), and transmission electron microscopy (TEM). The morphology tuning was controlled by the temperature of the reaction; the nanoparticles were synthesized via the hydrothermal method at 120°C, 140°C, and 160°C, respectively. The Rm and XRD spectra showed that all the nanoparticles were Fe3O4 in a pure magnetite phase. The obtained nanoparticles exhibited a high level of crystallinity with uniform morphology at each temperature, as can be observed through TEM and SEM. These magnetic nanoparticles exhibited good saturation magnetization and the resulting shapes were quasi-spheres, octahedrons, and cubes. The samples showed striking magnetic properties, which were examined by a vibrating sample magnetometer (VSM). It has been possible to obtain a good morphological control of nanostructured magnetite in a simple, economical, and scalable method by adjusting the temperature, without the modification of any other synthesis parameter

[Reported prevalence of dental caries in Mexican children and teenagers]

Abstract Dental caries is a serious multifactorial oral disease that causes demineralization of the tooth’s hard tissues and affects more than half of the world's population. The objective of this exploratory systematic review was to determine the prevalence of dental caries in Mexican children and adolescents, as well as related factors such as sex, nutritional status, type of dentition, education, living conditions, socioeconomic level, and the type of demographic area. The eligibility criteria to be considered were observational studies whose sample included Mexicans 0-15 years of age in which the prevalence or an index of dental caries had been evaluated. Eligible studies were identified through the search carried out in 6 databases and manual search, without publication time restriction. Fifty-four studies were found that met the eligibility criteria. In these included studies it was observed that, in the last decades, the prevalence of caries in Mexican children and adolescents exhibits a tendency to decrease this disease. In the 1980s, caries prevalences of up to 92.8% were reported; between 1990-1999, the highest reported prevalence was 97%; from 2000-2009, the highest reported prevalence was 95%; from 2010 to 2019 the highest prevalence was 94.6%; and from 2020 and 2021, prevalences of up to 88.5% were reported. Although there has been a decrease in the prevalence of caries in Mexican children, this disease continues to be linked to biological, behavioral and socioeconomic determinants. Resumen La caries dental es una enfermedad bucodental multifactorial grave que provoca la desmineralización de los tejidos duros del diente y afecta a más de la mitad de la población mundial. El objetivo de esta revisión sistemática exploratoria fue determinar la prevalencia de caries dental en niños y adolescentes mexicanos, así como los factores relacionados como el sexo, el estado nutricional, el tipo de dentición, la educación, las condiciones de vida, el nivel socioeconómico y el tipo de área demográfica. Los criterios de elegibilidad fueron estudios observacionales cuya muestra incluyera mexicanos de 0 a 15 años en los que se hubiera evaluado la prevalencia o un índice de caries dental. Los estudios elegibles fueron identificados mediante la búsqueda realizada en 6 bases de datos y de manera manual, sin restricción de tiempo de publicación. Se encontraron 54 estudios que cumplieron con los criterios de elegibilidad. En estos estudios incluidos se observó que en las últimas décadas la prevalencia de caries en niños y adolescentes mexicanos exhibe una tendencia a la baja. En la década de 1980, se reportaron prevalencias de caries de hasta 92.8%; entre 1990-1999, la mayor prevalencia reportada fue de 97%; de 2000-2009, la prevalencia más alta reportada fue de 95%; de 2010 a 2019 la mayor prevalencia fue de 94.6%; y de 2020 y 2021, se reportaron prevalencias de hasta 88.5%. Aunque ha habido un decremento en la prevalencia de caries en niños mexicanos, esta enfermedad continúa vinculada a determinantes biológicas, conductuales y socioeconómicas

Perspectives for the use of silver nanoparticles in dental practice

Hacemos una revisión de la perspectiva del uso a futuro de las nanopartículas de plata en práctica dental.Nanotechnology has been used for medical applications in several forms, including dental practice with the development of silver nanoparticles (Ag NPs) as a useful tool. The aim of this review was to identify the properties and appliances of Ag NPs in dental practice. Silver compounds and NPs have already been used as dental restorative material, endodontic retrofill cements, dental implants and caries inhibitory solution. Despite the effectiveness that Ag NPs has showed in dental practice, Ag NPs remain a controversial area of research with respect to their toxicity in biological and ecological systems. Therefore any application of Ag NPs in dentistry requires more studies. In order to avoided the toxicity of these materials Ag NPs can be temporarily used in dentistry

Study X-ray photoelectron spectroscopy determination of interactions between gold nanoparticles and epidermal growth factor for potential use in biomedicine

Nowadays, biomedical applications of gold nanoparticles coupled with Epidermal Growth Factor have attracted huge attention because of its theranostic activity, which could be useful for diagnosis and treatment of neurodegenerative diseases. Therefore, there is a great interest to know the nature of the intermolecular interactions between the gold nanoparticles and epidermal growth factor (EGF). A two-step synthesis was performed. In the first step, gold nanoparticles were synthesized by chemical reduction of tetrachloroauric acid using sodium citrate as reducing and capping agent. Secondly, gold nanoparticles were coupled with EGF. The obtained nanoparticles were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and zeta-potential before and after being coupled with the EGF. Gold nanoparticles with an average diameter of 8.09 nm were obtained. After coupled with EGF, the particle average diameter increased to 9.14 nm. X-ray photoelectron spectroscopy showed an electrostatic interaction between gold nanoparticles and EGF. Zeta potential corroborated these results. Thus, it was possible for the first time to identify the interactions between these two chemical species. Since gold nanoparticles may act as carriers of EGF, these results illustrate the great potential for the use of this bionanocomposite in neurodegenerative disease treatment.UAEME

New Trends for the Processing of Poly(Methyl Methacrylate) Biomaterial for Dental Prosthodontics

Rehabilitation of masticatory function in patients with absent teeth with removable dentures is an established form of treating partial or complete dentition in edentulous patients. The developments in recent decades with dental implants dominate current dental research. However, medical contraindications, a negative attitude toward implants, or financial limitations on the part of the patients limit their universal applicability, so the rehabilitation with dental prostheses still makes up a significant portion of everyday clinical practice. Conversely, removable dentures are used in the critical conditions of the oral cavity. There are about 500 strains of microorganisms in the mouth, which form the biofilm in an acidic environment causing several issues, such as denture stomatitis, deterioration of the periodontal status of the remaining teeth, or carious lesions in the supporting teeth. Therefore, it is very important to choose a suitable material for the prosthesis. Poly(methyl methacrylate) (PMMA) is an acrylic resin usually used with a long tradition for prosthetic purposes. The aim of this chapter is to present the trends for the processing of PMMA. It includes the chemical synthesis, conventional thermal processing of this acrylic resin, the new processing technique assisted with ultrasound, the antibacterial effect on PMMA with nanoparticles, and the cytotoxicity, genotoxicity, and mutagenesis of this material

The modulation of the hexosamine biosynthetic pathway impacts the localization of CD36 in macrophages

CD36 is a type 2 cell surface scavenger receptor expressed in various tissues. In macrophages, CD36 recognizes oxidized low-density lipoprotein (ox-LDL), which promotes the formation of foam cells, the first step toward an atherosclerotic arterial lesion. CD36 possesses a variety of posttranslational modifications, among them N-glycosylation and O-GlcNAc modification. Some of the roles of these modifications on CD36 are known, such as N-linked glycosylation, which provides proper folding and trafficking to the plasma membrane in the human embryonic kidney. This study aimed to determine whether variations in the availability of UDP-GlcNAc could impact Rab-5-mediated endocytic trafficking and, therefore, the cellular localization of CD36. These preliminary results suggest that the availability of the substrate UDP-GlcNAc, modulated in response to treatment with Thiamet G (TMG), OSMI-1 (O-GlcNAcylation enzymes modulators) or Azaserine (HBP modulator), influences the localization of CD36 in J774 macrophages, and the endocytic trafficking as evidenced by the regulatory protein Rab-5, between the plasma membrane and the cytoplasm