Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
1.
Colloids Surf B Biointerfaces ; 226: 113305, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37084526

RESUMO

The demand for sustainable products is increasing worldwide and cosmetic industry is not an exception. Besides exploring nature as source of new ingredients, their production must be sustainable and should use environmentally friendly processes. In this work, biogenic silica microparticles were synthesized from sugarcane ash, and their potential application as cosmetic and skincare ingredient was evaluated. For such application, several properties were validated, including cytotoxicity in skin keratinocytes, potential sensitization effect on skin peptides, stimulation of pro-collagen I alpha 1, wound healing capacity, as well as the ingredient stability along a storage period. Biogenic silica showed to be non-cytotoxic on skin keratinocytes, at concentrations up to 5 wt%, and non-skin sensitizer. A positive effect on the stimulation of pro-collagen I alpha 1 suggests a potential anti-ageing activity, while the migration of fibroblasts to a wounded area suggests a regenerative capacity. Under an accelerated stability study, biogenic silica showed an increase on the loss on drying, but no changes were observed on its functional properties, mainly oil absorption capacity, as well the microbiological quality, which was maintained. Overall, novel biogenic silica microparticles produced from a sustainable source are safe, stable over time and have potential to be used as a cosmetic and skincare ingredient.


Assuntos
Cosméticos , Testes de Toxicidade , Qualidade de Produtos para o Consumidor , Fenômenos Químicos , Colágeno
2.
J Prosthet Dent ; 130(1): 87-95, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34711406

RESUMO

STATEMENT OF PROBLEM: Microgap and bacterial microleakage at the implant-prosthetic abutment interface are recognized concerns for implant-supported restorations, leading to inflammation of the peri-implant tissues, with deleterious consequences for crestal bone levels. However, little is known regarding the interface established between the implant and the healing abutment or cover screw placed for the osseointegration phase. PURPOSE: The purpose of this in vitro study was to characterize the implant-cover screw and implant-healing abutment interfaces of a platform-switched implant system to determine the microgap and bacterial microleakage of the system and evaluate the biological response and functionality of an interface sealing agent. MATERIAL AND METHODS: The interfacial microgaps of the implant-healing abutment and implant-cover screw interfaces were characterized by scanning electron microscopy (n=10), and bacterial microleakage was evaluated after colonization with Enterococcus faecalis in a 30-day follow-up (n=10). The sealing efficacy and irritation potential of a silicone-based sealer were determined by using the hen's egg test on chorioallantoic membrane assay. The 2-sample t test was performed to compare means between groups, and data presented with the Kaplan-Meier method were compared statistically by using the log-rank test (α=.05). RESULTS: The interfacial microgap was less than 2.5 µm for both systems. Bacterial microleakage was noted in approximately 50% of the specimens, particularly at early time points, at both the healing abutment and cover screw interfaces. The silicone-based sealer prevented bacterial leakage in the experimental setting. CONCLUSIONS: The implant-healing abutment and implant-cover screw interfaces of the tested system, despite the low microgap, allowed for bacterial microleakage after internal colonization. The use of a nonirritating silicone-based sealing agent effectively sealed the system.


Assuntos
Implantes Dentários , Osseointegração , Animais , Feminino , Galinhas , Dente Suporte , Implantes Dentários/microbiologia , Bactérias , Projeto do Implante Dentário-Pivô
3.
JAMA ; 317(2): 165-182, 2017 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-28097354

RESUMO

Importance: Elevated systolic blood (SBP) pressure is a leading global health risk. Quantifying the levels of SBP is important to guide prevention policies and interventions. Objective: To estimate the association between SBP of at least 110 to 115 mm Hg and SBP of 140 mm Hg or higher and the burden of different causes of death and disability by age and sex for 195 countries and territories, 1990-2015. Design: A comparative risk assessment of health loss related to SBP. Estimated distribution of SBP was based on 844 studies from 154 countries (published 1980-2015) of 8.69 million participants. Spatiotemporal Gaussian process regression was used to generate estimates of mean SBP and adjusted variance for each age, sex, country, and year. Diseases with sufficient evidence for a causal relationship with high SBP (eg, ischemic heart disease, ischemic stroke, and hemorrhagic stroke) were included in the primary analysis. Main Outcomes and Measures: Mean SBP level, cause-specific deaths, and health burden related to SBP (≥110-115 mm Hg and also ≥140 mm Hg) by age, sex, country, and year. Results: Between 1990-2015, the rate of SBP of at least 110 to 115 mm Hg increased from 73 119 (95% uncertainty interval [UI], 67 949-78 241) to 81 373 (95% UI, 76 814-85 770) per 100 000, and SBP of 140 mm Hg or higher increased from 17 307 (95% UI, 17 117-17 492) to 20 526 (95% UI, 20 283-20 746) per 100 000. The estimated annual death rate per 100 000 associated with SBP of at least 110 to 115 mm Hg increased from 135.6 (95% UI, 122.4-148.1) to 145.2 (95% UI 130.3-159.9) and the rate for SBP of 140 mm Hg or higher increased from 97.9 (95% UI, 87.5-108.1) to 106.3 (95% UI, 94.6-118.1). For loss of DALYs associated with systolic blood pressure of 140 mm Hg or higher, the loss increased from 95.9 million (95% uncertainty interval [UI], 87.0-104.9 million) to 143.0 million (95% UI, 130.2-157.0 million) [corrected], and for SBP of 140 mm Hg or higher, the loss increased from 5.2 million (95% UI, 4.6-5.7 million) to 7.8 million (95% UI, 7.0-8.7 million). The largest numbers of SBP-related deaths were caused by ischemic heart disease (4.9 million [95% UI, 4.0-5.7 million]; 54.5%), hemorrhagic stroke (2.0 million [95% UI, 1.6-2.3 million]; 58.3%), and ischemic stroke (1.5 million [95% UI, 1.2-1.8 million]; 50.0%). In 2015, China, India, Russia, Indonesia, and the United States accounted for more than half of the global DALYs related to SBP of at least 110 to 115 mm Hg. Conclusions and Relevance: In international surveys, although there is uncertainty in some estimates, the rate of elevated SBP (≥110-115 and ≥140 mm Hg) increased substantially between 1990 and 2015, and DALYs and deaths associated with elevated SBP also increased. Projections based on this sample suggest that in 2015, an estimated 3.5 billion adults had SBP of at least 110 to 115 mm Hg and 874 million adults had SBP of 140 mm Hg or higher.


Assuntos
Saúde Global/estatística & dados numéricos , Hipertensão/epidemiologia , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea , Causas de Morte , Feminino , Inquéritos Epidemiológicos , Humanos , Hipertensão/complicações , Hipertensão/mortalidade , Hemorragias Intracranianas/etiologia , Hemorragias Intracranianas/mortalidade , Masculino , Pessoa de Meia-Idade , Método de Monte Carlo , Isquemia Miocárdica/etiologia , Isquemia Miocárdica/mortalidade , Distribuição Normal , Prevalência , Anos de Vida Ajustados por Qualidade de Vida , Insuficiência Renal Crônica/etiologia , Insuficiência Renal Crônica/mortalidade , Medição de Risco , Distribuição por Sexo , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/mortalidade , Sístole , Incerteza
4.
Biomed Mater ; 11(4): 045007, 2016 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-27508333

RESUMO

Magnesium alloys are regarded as potential biodegradable load-bearing biomaterials for orthopedic applications due to their physico-chemical and biomechanical properties. However, their clinical applicability is restricted by their high degradation rate, which limits the physiological reconstruction of the neighbouring tissues. In this work, a multifunctional coating architecture was developed on an AZ31 alloy by conjoining an anodization process with the deposition of a polymeric-based layer consisting of polyether imine reinforced with hydroxyapatite nanoparticles, aiming at improved control of the corrosion activity and biological performance of the Mg substrate. Anodization and coating protocols were evaluated either independently or combined for corrosion resistance and biological behaviour, i.e. the irritation potential and angiogenic capability within a chicken chorioallantoic membrane assay, and bone tissue response following tibia implantation within a rabbit model. Electrochemical impedance spectroscopy (EIS) analysis showed that coated Mg constructs, particularly anodized plus coated with AZ31, exhibited excellent stability compared to the anodized alloy and, particularly, to the bare AZ31. Microtomographic evaluation of the implanted samples correlated with these degradation results. Mg constructs displayed a non-irritating behaviour, and were associated with high levels of vascular ingrowth. Bone ingrowth neighbouring the implanted constructs was observed for all samples, with coated and anodized plus coated samples presenting the highest bone formation. Gene expression analysis suggested that the enhanced bone tissue formation was associated with the boost in osteogenic activity through Runx2 upregulation, following the activation of PGC-1α/ERRα signaling. Overall, the developed multifunctional coatings appear to be a promising strategy to obtain safe and bioactive biodegradable Mg-based implants with potential applications within bone tissue.


Assuntos
Ligas/química , Materiais Revestidos Biocompatíveis/química , Magnésio/química , Implantes Absorvíveis , Animais , Galinhas , Membrana Corioalantoide/metabolismo , Corrosão , Durapatita/química , Impedância Elétrica , Eletroquímica , Regulação da Expressão Gênica , Masculino , Teste de Materiais , Neovascularização Patológica , Polímeros/química , Coelhos , Transdução de Sinais , Análise Espectral , Tíbia/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA