A influência do processo de produção de scaffolds na regeneração óssea

The raising level of bone defects worldwide has become a major concern of public health. Autografts, allografts and xenografts are some alternatives that are currently being used to overcome bone related problems. However the risks of infection and immunological response from the patient are very high. To surpass these handicaps, new biodegradable and biocompatible structures (scaffolds) have been produced in the area of tissue engineering to be used as temporarily bone substitutes. These structures allow cell adhesion and proliferation, while giving mechanical support to the newly bone formation. Several biocompatible materials have been used so far for scaffolds production. Nevertheless it is fundamental that the right production method is chosen, since it will influence the regenerative process. In this study a chitosan/alginate/β-TCP scaffold was produced by three different techniques: rapid prototyping using a Fab@home 3D printer, freeze-drying and foam replication method. The scaffolds were characterized by Fourier transformed Infrared spectroscopy, X-ray diffraction, Energy dispersion Spectroscopy, Scanning Electronic microscopy and water contact angle. Moreover, the porosity, mechanical properties, swelling profile, and degradation behavior of the different scaffolds were also characterized. The cytotoxic profile of the scaffolds was studied using a rezazurin assay. The cellular adhesion, proliferation and internalization in the scaffolds were studied by optical, scanning electronic and confocal laser scanning microscopy. The antimicrobial properties of the different scaffolds were tested against Staphylococcus Aureus, using a Kirby-Bauer disk diffusion method. All the results revealed that the chitosan/alginate/β-TCP scaffolds produced by rapid prototyping had the most suitable properties for being applied in bone regeneration.O aumento de defeitos ósseos nas últimas décadas tem se tornado um problema de saúde a nível mundial. Os autoenxertos, aloenxertos e xenoenxertos são algumas das alternativas terapêuticas utilizadas para a reparação/regeneração dos defeitos do tecido ósseo. Contudo o elevado risco de infeção e rejeição têm limitado a sua aplicação. A engenharia de tecidos tem procurado soluções para ultrapassar estes problemas, nomeadamente atravéz da produção de estruturas temporariamente substitutas do tecido ósseo que sejam biocompatíveis e biodegradáveis. Estas estruturas são conhecidas como matrizes 3D (scaffolds), que permitem a adesão e proliferação celular, fornecendo suporte mecânico até á formação de novo tecido ósseo. O sucesso de um scaffold depende das suas propriedades químicas, mecânicas e biológicas. Na produção destas estruturas tridimensionais têm sido usados vários materiais biocompatíveis. Contudo também é importante ter em conta que a técnica usada na produção dos scaffolds vai influenciar diretamente as suas propriedades e consequentemente a sua ação na regeneração óssea. Neste estudo scaffolds de quitosano/alginato/β-TCP foram produzidos usando três técnicas de produção diferentes: prototipagem rápida com uma impressora 3D Fab@home, método de sublimação e método de replicação de esponja. Os scaffolds produzidos foram caracterizados de forma a perceber qual a técnica que permitiria a produção de scaffolds com propriedades adequadas para a regeneração óssea. Os diferentes scaffolds foram caracterizados por espectroscopia de infravermelhos, difração de raio X, espectroscopia de dispersão de energia, microscopia electrónica de varrimento e o carácter hidrofílico foi caracterizado atravéz da determinação do ângulo de contacto. Por outro lado, a porosidade e as propriedades mecânicas dos materiais foram analisadas, assim como o inchaço e a sua degradação. O perfil citotóxico dos scaffolds foi avaliado usando um ensaio de rezazurina e a adesão, proliferação e internalização celular nos scaffolds foi estudada por microscopia ótica, microscopia electrónica de varrimento e microscopia confocal. As propriedades antibacterianas foram avaliadas usando o método de difusão em placa de Kirby-Bauer, usando a bactéria Staphylococcus Aureus como modelo. Os resultados obtidos mostraram que os scaffolds de quitosano/alginato/β-TCP produzidos por prototipagem rápida apresentaram propriedades adequadas para que futuramente possam ser usados na regeneração óssea

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p < 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures

Impact of COVID-19 on Diagnostic Cardiac Procedural Volume in Oceania: The IAEA Non-Invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Objectives: The INCAPS COVID Oceania study aimed to assess the impact caused by the COVID-19 pandemic on cardiac procedure volume provided in the Oceania region. Methods: A retrospective survey was performed comparing procedure volumes within March 2019 (pre-COVID-19) with April 2020 (during first wave of COVID-19 pandemic). Sixty-three (63) health care facilities within Oceania that perform cardiac diagnostic procedures were surveyed, including a mixture of metropolitan and regional, hospital and outpatient, public and private sites, and 846 facilities outside of Oceania. The percentage change in procedure volume was measured between March 2019 and April 2020, compared by test type and by facility. Results: In Oceania, the total cardiac diagnostic procedure volume was reduced by 52.2% from March 2019 to April 2020, compared to a reduction of 75.9% seen in the rest of the world (p<0.001). Within Oceania sites, this reduction varied significantly between procedure types, but not between types of health care facility. All procedure types (other than stress cardiac magnetic resonance [CMR] and positron emission tomography [PET]) saw significant reductions in volume over this time period (p<0.001). In Oceania, transthoracic echocardiography (TTE) decreased by 51.6%, transoesophageal echocardiography (TOE) by 74.0%, and stress tests by 65% overall, which was more pronounced for stress electrocardiograph (ECG) (81.8%) and stress echocardiography (76.7%) compared to stress single-photon emission computerised tomography (SPECT) (44.3%). Invasive coronary angiography decreased by 36.7% in Oceania. Conclusion: A significant reduction in cardiac diagnostic procedure volume was seen across all facility types in Oceania and was likely a function of recommendations from cardiac societies and directives from government to minimise spread of COVID-19 amongst patients and staff. Longer term evaluation is important to assess for negative patient outcomes which may relate to deferral of usual models of care within cardiology