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Previously, a new biodegradable poly(ester urethane urea) was synthesized based on polycaprolactone-diol and fish gelatin (PU-Gel). In this work, the potential of this new material for neural tissue engineering is evaluated. Membranes with randomly oriented fibers and with aligned fibers are produced using electrospinning and characterized regarding their mechanical behavior under both dry and wet conditions. Wet samples exhibit a lower Young's modulus than dry ones and aligned membranes are stiffer and more brittle than those randomly oriented. Cyclic tensile tests are conducted and high values for recovery ratio and resilience are obtained. Both membranes exhibited a hydrophobic surface, measured by the water contact angle (WCA). Human mesenchymal stem cells from umbilical cord tissue (UC-MSCs) and human neural stem cells (NSCs) are seeded on both types of membranes, which support their adhesion and proliferation. Cells stained for the cytoskeleton and nucleus in membranes with aligned fibers display an elongated morphology following the alignment direction. As the culture time increased, higher cell viability is obtained on randomfibers for UC-MSCs while no differences are observed for NSCs. The membranes support neuronal differentiation of NSCs, as evidenced by markers for a neuronal filament protein (NF70) and for a microtubule-associated protein (MAP2).
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A renal infarction occurs when kidney's arterial blood supply is compromised, causing parenchymal necrosis and loss of function. It is a relatively uncommon complication and its treatment is time-dependent. We present a case where a female patient with a history of bilateral aortic-iliac stenting over 10 years before presented with chest pain, palpitations, and dyspnea associated with hypertension. The patient progressed with an acute worsening of renal function and anuria, with an urgent need for renal replacement therapy. The abdominal CT angiography confirmed a complete chronic stent thrombosis and a recent occlusion of the right renal artery causing an acute renal infarction; however, this exam was performed more than 72 hours after admission. There was no longer indication for reperfusion therapy, taking into account the time course. This case reinforces the importance of a thorough clinical history and awareness of risk factors to raise the suspicion of renal infarction that should lead to an early contrast-enhanced CT scan so that adequate therapy can be performed.
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The small pore size of electrospun membranes prevents their use as three-dimensional scaffolds. In this work, we produced polycaprolactone (PCL) electrospun fibrous membranes with expanded pores by incorporating chitosan (CS) granules into the PCL solution. Scanning electron microscopy images confirmed the presence of the CS granules embedded in the PCL fibers, creating an open structure. Tensile testing results showed that the addition of CS decreased both Young's modulus and the yield stress, but co-electrospun membranes (PCL fibers blended with CS-containing PCL fibers) exhibited higher values compared to single electrospun membranes (CS-containing PCL fibers). Human fibroblasts adhered to and proliferated on all scaffolds. Nuclear staining revealed that cells populated the entire scaffold when CS granules were present, while in PCL membranes, cells were mostly limited to the surface due to the small pore size. Overall, our findings demonstrate that electrospun membranes containing CS granules have sufficiently large pores to facilitate fibroblast infiltration without compromising the mechanical stability of the structure.
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Cancer is one of the leading causes of death worldwide. Conventional treatments such as surgery, chemotherapy, and radiotherapy have limitations and severe side effects. Magnetic hyperthermia (MH) is an alternative method that can be used alone or in conjunction with chemotherapy or radiotherapy to treat cancer. Cobalt ferrite particles were synthesized using an innovative biogenic sol-gel method with powder of coconut water (PCW). The obtained powders were subjected to heat treatments between 500 °C and 1100 °C. Subsequently, they were characterized by thermal, structural, magnetic, and cytotoxic analyses to assess their suitability for MH applications. Through X-ray diffraction and Raman spectroscopy, it was possible to confirm the presence of the pure phase of CoFe2O4 in the sample treated at 1100 °C, exhibiting a saturation magnetization of 84 emu/g at 300 K and an average grain size of 542 nm. Furthermore, the sample treated at 1100 °C showed a specific absorption rate (SAR) of 3.91 W/g, and at concentrations equal to or below 5 mg/mL, is non-cytotoxic, being the most suitable for biomedical applications.
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Magnetismo , Neoplasias , Humanos , Cobalto/química , Compostos Férricos/químicaRESUMO
Therapeutic solutions for injuries in the peripheral nervous system are limited and not existing in the case of the central nervous system. The electrical stimulation of cells through a cell-supporting conductive scaffold may contribute to new therapeutic solutions for nerve regeneration. In this work, biocompatible Polylactic acid (PLA) fibrous scaffolds incorporating Fe(III)Tosylate (FeTos) were produced by electrospinning a mixture of PLA/FeTos solutions towards a rotating cylinder, inducing fiber alignment. Fibers were coated with the conductive polymer Poly(3,4 ethylenedioxythiophene) (PEDOT) formed by vapor-phase polymerization of EDOT at 70 °C for 2 h. Different solvents (ETH, DMF and THF) were used as FeTos solvents to investigate the impact on the scaffold's conductivity. Scaffold conductivity was estimated to be as high as 1.50 × 10-1 S/cm when FeTos was dissolved in DMF. In vitro tests were performed to evaluate possible scaffold cytotoxicity, following ISO 10993-5, revealing no cytotoxic effects. Differentiation and growth of cells from the neural cell line SH-SY5Y seeded on the scaffolds were also assessed, with neuritic extensions observed in cells differentiated in neurons with retinoic acid. These extensions tended to follow the preferential alignment of the scaffold fibers.
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Introduction Recurrent hospitalizations for worsening heart failure (WHF) represent a major global public health concern, resulting in significant individual morbimortality and socioeconomic costs. This real-life study aimed to determine the rate and predictors of readmission for WHF in a cohort of outpatients with chronic heart failure (CHF) followed in a heart failure clinic (HFC) at a university hospital. Methods We conducted a longitudinal, observational, and retrospective study of all consecutive CHF patients seen at the HFC of the São Francisco Xavier Hospital, Lisbon, by a multidisciplinary team in 2019. The patients were followed for one year and were on optimized therapy. The inclusion criteria for the study were patients who had been hospitalized and subsequently discharged at least three months prior to their enrollment. Patient demographics, heart failure (HF) characterization, comorbidities, pharmacological treatment, treatments of decompensated HF in the day hospital (DH), hospitalizations for WHF, and death were recorded. We applied logistic regression analysis to assess predictors of hospital readmission for HF. Results A total of 351 patients were included: 90 patients (26%) had WHF requiring treatment with intravenous diuretics in the DH; 45 patients (mean age: 79.1 ± 9.0 years) were readmitted for decompensated HF within one year (12.8%) with no gender difference, while 87.2% of the patients (mean age: 74.9 ± 12.1 years) were never readmitted. Readmitted patients were significantly older than those who were not (p=0.031). Additionally, they had a higher New York Heart Association (NYHA) functional classification (p<.001), were on a higher daily dose of furosemide (p=0.008) at the time of the inclusion visit, were more frequently affected by the chronic obstructive pulmonary disease (COPD) (p=0.004); had been treated more often in the DH for WHF (p<.001) and had a higher mortality rate (p<.001) at one year. Conclusions This study aimed to determine WHF patient readmission rates and predictors. According to our results, a higher NYHA class, the need for treatment in the DH for WHF, a daily dose of furosemide equal to or greater than 80 mg, and COPD were predictors of readmission for WHF. CHF patients continue to experience WHF and recurrent hospitalizations despite therapeutic advances and close follow-up in the HFC with the multidisciplinary team. Besides COPD, the HF readmission risk factors found were mainly related to advanced disease. Furthermore, the structured and multidisciplinary approach of our disease management program likely contributed to our relatively low rate of readmissions.
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Metamizole is a drug with analgesic and antipyretic properties widely available in Portugal. Its use is highly controversial because of the risk of agranulocytosis, a rare but serious adverse event. A 70-year-old female patient with a recent history of treatment with metamizole for post-surgery fever and pain presented to the ED with sustained fever, diarrhea, and painful mouth ulcers. Laboratory tests revealed agranulocytosis. The patient was placed under protective isolation and started treatment with granulocyte-colony stimulating factor (G-CSF) and empiric antibiotic therapy with piperacillin/tazobactam and vancomycin for neutropenic fever. After an extensive workup, no source of infection was identified. During hospitalization, infectious and neoplastic causes of agranulocytosis were investigated, but the results were negative. Metamizole-induced agranulocytosis was suspected. The patient completed a total of three days of G-CSF and eight days of empiric antibiotic therapy with sustained clinical improvement. She was discharged completely asymptomatic and remained clinically stable during follow-up without a resurgence of agranulocytosis. This case report is intended to increase awareness of metamizole-induced agranulocytosis. While this is a well-known side effect, it is also often overlooked. It is paramount that both physicians and patients know how to correctly manage metamizole to prevent and promptly treat agranulocytosis.
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Acute heart failure is a frequent cause of hospital admission in Portugal, and has an increasing tendency given the aging population. Although most admissions for acute heart failure are caused by congestive conditions, not all patients have a congestive phenotype, reflecting the complexity of a process with multiple pathophysiological pathways. The use of diuretics, usually loop diuretics, is the mainstay of treatment for congestion. However, many patients develop resistance, thus constituting a challenge with no consensual solution to date, despite extensive debate over the years. Despite its frequent use in clinical practice, the co-administration of albumin and furosemide remains controversial in the management of patients with acute heart failure, hypoalbuminemia, and diuretic resistance. This review addresses the pathophysiological mechanisms of congestion in patients with acute heart failure and explores the theoretical basis that supports the co-administration of albumin and furosemide in this clinical context. It is intended to clarify the potential benefit of the combined approach in this specific population and identify possible gaps in the literature that could be the subject of future studies.
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Furosemida , Insuficiência Cardíaca , Humanos , Furosemida/uso terapêutico , Diuréticos/uso terapêutico , Inibidores de Simportadores de Cloreto de Sódio e Potássio/uso terapêutico , Albuminas/uso terapêuticoRESUMO
The development of new cancer treatment options, such as multifunctional devices, allows for a more personalized treatment, avoiding the known severe side effects of conventional options. In this context, on-demand drug delivery systems can actively control the rate of drug release offering a precise control of treatment. Magnetically and thermally controlled drug delivery systems have been explored as on-demand devices to treat chronic diseases and cancer tumors. In the present work, dual-stimuli responsive systems were developed by incorporating Fe3O4 magnetic nanoparticles (NPs) and poly(N-isopropylacrylamide) (PNIPAAm) microgels into electrospun polymeric fibers for application in cancer treatment. First, Fe3O4 NPs with an average diameter of 8 nm were synthesized by chemical precipitation technique and stabilized with dimercaptosuccinic acid (DMSA) or oleic acid (OA). PNIPAAm microgels were synthesized by surfactant-free emulsion polymerization (SFEP). Poly(vinyl alcohol) (PVA) was used as a fiber template originating fibers with an average diameter of 179 ± 14 nm. Stress tests of the membranes showed that incorporating both microgels and Fe3O4 NPs in electrospun fibers increases their Young's modulus. Swelling assays indicate that PVA membranes have a swelling ratio of around 3.4 (g/g) and that the presence of microgels does not affect its swelling ability. However, with the incorporation of Fe3O4 NPs, the swelling ratio of the membranes decreases. Magnetic hyperthermia assays show that a higher concentration of NPs leads to a higher heating ability. The composite membrane with the most promising results is the one incorporated with DMSA-coated NPs, since it shows the highest temperature variation, 5.1 °C. To assess the membranes biocompatibility and ability to promote cell proliferation, indirect and direct contact cell viability assays were performed, as well as cell adhesion assays. Following an extract method viability assay, all membrane designs did not reveal cytotoxic effects on dermal fibroblasts and melanoma cancer cells, after 48 h exposure and support long-term viability. The present work demonstrates the potential of dual-stimuli composite membranes for magnetic hyperthermia and may in the future be used as an alternative cancer treatment particularly in anatomically reachable solid tumors.
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Hipertermia Induzida , Microgéis , Nanofibras , Neoplasias , Álcool de Polivinil , Fenômenos MagnéticosRESUMO
Hybrid scaffolds obtained by combining two or more biopolymers are studied in the context of tissue regeneration due to the possibility of achieving new functional properties or structural features. The aim of this work was to produce a new type of hybrid polycaprolactone (PCL)/chitosan (CS) electrospun mat through the controlled deposition of CS flakes interspaced between the PCL fibers. A poly(ethylene oxide) (PEO) solution was used to transport CS flakes with controlled size. This, and the PCL solution, were simultaneously electrospun onto a rotatory mandrel in a perpendicular setup. Different PCL/CS mass ratios were also studied. The morphology of the resulting fibers, evaluated by SEM, confirmed the presence of the CS flakes between the PCL fibers. The addition of PEO/CS fibers resulted in hydrophilic mats with lower Young's modulus relatively to PCL mats. In vitro cell culture results indicated that the addition of CS lowers both the adhesion and the proliferation of human dermal fibroblasts. The present work demonstrates the feasibility of achieving a controlled deposition of a polymeric component in granular form onto a collector where electrospun nanofibers are being deposited, thereby producing a hybrid scaffold.
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Introduction The marked increase in life expectancy seen in Portugal in the last five decades led to a change in the profile of patients being most commonly admitted in internal medicine wards. In deciding the best care for these patients, prognostication models are needed in order to reduce readmissions, mortality, and adequate care. We aimed to study short and long-term mortality and predictors of all-cause mortality, independently of cause admission, of patients admitted in an internal medicine ward. Methods This two-part, single-center study enrolled patients from October 2013 to October 2014 with a follow-up of 60 months. Results A total of 681 patients were included; the mean age was 75.86 years with 60.4% females. The most frequent comorbidities were anemia, hypertension, and renal impairment. More than half of the population died in the follow-up period (51.5%). Deaths were significantly higher in the first six months after discharge (53% of all deaths) and then decreased abruptly to 11.6% in the second half-year after discharge. Based on the multivariate logistic regression model, with age over 80 years, anemia and neoplasm were independent predictors of short-term (p<0.001, p=0.001, p<0.001, respectively) and long-term (p<0.001 for the three conditions) mortality. Heart failure (p=0.018) and diabetes (p=0.025) were also predictors of long-term mortality. Conclusion High mortality, mainly in the first six months after discharge, elicits strategies targeting transition of care and close follow-up in the first months, which can be the key to improving outcomes. Identification of patients at higher risk may help design realistic models aiming to improve care for this frail population and decrease morbimortality.
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BACKGROUND: Sleep-disordered breathing (SDB) is prevalent in heart failure (HF). Yet, scarce data exist on sleep-patterns in acute HF and differences in specific subgroups. Our goal was to assess SDB prevalence in hospitalized patients with decompensated HF across the entire spectrum of left ventricle ejection fraction (LVEF). METHODS: Single-center retrospective study enrolling patients admitted for acute HF between 2013 and 2018. All patients were screened for SDB with an ApneaLink™ Plus device before discharge while euvolemic and receiving oral therapy. Those with a sleep study time < 3 h were excluded. HF with reduced, moderately reduced, and preserved LVEF (HFrEF, HFmrEF, and HFpEF) was defined by a LVEF < 40%, 40-49%, and ≥ 50%, respectively. SDB was defined by an apnea-hypopnea index (AHI) ≥ 5/h. RESULTS: Overall, 221 patients were included (mean age 75 ± 11 years). Seventy-two (33%) had HFrEF, 26 (11%) HFmrEF, and 123 (56%) HFpEF. In total, 176 (80%) met the criteria for mild SDB, while 59% and 38% had an AHI ≥ 15/h or ≥ 30/h, respectively. SDB prevalence was high and similar between HFrEF, HFmrEF, and HFpEF. Yet, SDB was often more severe in HFrEF when compared to HFpEF. HFmrEF had intermediate characteristics, with an AHI closer to HFrEF. CONCLUSION: In a cohort of patients admitted for acute HF, SDB was highly prevalent in all subgroups, including HFmrEF. The pervasiveness and severity of SDB was particularly noted in HFrEF. These findings suggest that routine SDB screening may be warranted following acute HF.
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Insuficiência Cardíaca , Síndromes da Apneia do Sono , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Volume Sistólico , Função Ventricular EsquerdaRESUMO
Heart failure (HF) is a chronic progressive disease with high morbimortality and poor quality of life (QoL). Palliative care significantly improves clinical outcomes but few patients receive it, in part due to challenging decisions about prognosis. This retrospective study, included all patients consecutively discharged from an Acute Heart Failure Unit over a period of one year, aiming to assess the accuracy of the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score in predicting mortality. Additionally, predictors of death at one and three years were explored using a multivariate regression model. The MAGGIC score was useful in predicting mortality, without significant difference between mortality observed at three-years follow-up compared with a mortality given by the score (p=0.115). Selected variables were statistically compared showing that poor functional status, high New York Heart Association (NYHA) at discharge, psychopharmacs use, and high creatininemia were associated with higher mortality (p<0.05). The multivariate regression model identified three predictors of one-year mortality: psychopharmacs baseline use (OR=4.110; p=0.014), angiotensin-converting enzyme inhibitors/angiotensin receptor blocker (ACEI/ARB) medication at discharge (OR=0.297; p=0.033), and higher admission's creatinine (OR=2.473; p=0.028). For three-year mortality outcome, two variables were strong independent predictors: psychopharmacs (OR=3.330; p=0.022) and medication with ACEI/ARB at discharge (OR=0.285; p=0.018). Models' adjustment was assessed through the receiver operating characteristic (ROC) curve. The best model was the one-year mortality (area under the curve, AUC 81%), corresponding to a good discrimination power. Despite prognostication, when setting goals of care an individualised patient-centred approach is imperative, based on the patient's objectives and needs. Risk factors related to poorer outcomes should be considered, in particular, higher NYHA at discharge which also represents symptom burden. Hospitalisation is an opportunity to optimize global care for heart failure patients including palliative care.
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Poly(hydroxyalkanoates) (PHAs) with differing material properties, namely, the homopolymer poly(3-hydroxybutyrate), P(3HB), the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), with a 3HV content of 25 wt.% and a medium chain length PHA, and mcl-PHA, mainly composed of 3-hydroxydecanoate, were studied as scaffolding material for cell culture. P(3HB) and P(3HB-co-3HV) were individually spun into fibers, as well as blends of the mcl-PHA with each of the scl-PHAs. An overall biopolymer concentration of 4 wt.% was used to prepare the electrospinning solutions, using chloroform as the solvent. A stable electrospinning process and good quality fibers were obtained for a solution flow rate of 0.5 mL h-1, a needle tip collector distance of 20 cm and a voltage of 12 kV for P(3HB) and P(3HB-co-3HV) solutions, while for the mcl-PHA the distance was increased to 25 cm and the voltage to 15 kV. The scaffolds' hydrophilicity was significantly increased under exposure to oxygen plasma as a surface treatment. Complete wetting was obtained for the oxygen plasma treated scaffolds and the water uptake degree increased in all treated scaffolds. The biopolymers crystallinity was not affected by the electrospinning process, while their treatment with oxygen plasma decreased their crystalline fraction. Human dermal fibroblasts were able to adhere and proliferate within the electrospun PHA-based scaffolds. The P(3HB-co-3HV): mcl-PHA oxygen plasma treated scaffold highlighted the most promising results with a cell adhesion rate of 40 ± 8%, compared to 14 ± 4% for the commercial oxygen plasma treated polystyrene scaffold AlvetexTM. Scaffolds based on P(3HB-co-3HV): mcl-PHA blends produced by electrospinning and submitted to oxygen plasma exposure are therefore promising biomaterials for the development of scaffolds for tissue engineering.
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BACKGROUND: In patients with heart failure (HF) and reduced ejection fraction (HFrEF) with or without type 2 diabetes mellitus, the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin was recently shown to reduce the risk of worsening HF or death from cardiovascular causes in the dapagliflozin in patients with heart failure and reduced ejection fraction (DAPA-HF) trial. Our goal was to investigate how many patients in a real-world setting would be eligible for dapagliflozin according to the DAPA-HF enrolment criteria. METHODS: This is a single-center retrospective study enrolling consecutive, unselected patients followed up in an HF clinic from 2013 to 2019. Key DAPA-HF inclusion criteria (i.e., left ventricular ejection fraction [LVEF] ≤40% and NT-proBNP ≥600 pg/mL [or ≥900 pg/mL if atrial fibrillation]) and exclusion criteria (estimated glomerular filtration rate [eGFR] <30 mL/kg/1.73 m2 and systolic blood pressure [SBP] <95 mm Hg) were considered. RESULTS: Overall, 479 patients (age 76 ± 13 years; 50.5% male; 78.9% hypertensive; 45.1% with an eGFR <60 mL/min/1.73 m2; 36.5% with TD2M; and 33.5% with ischaemic HF) were assessed. The median SBP was 128.5 (112.0-146.0) mm Hg, mean eGFR was 50.8 ± 23.7 mL/min/1.73 m2, and median NT-proBNP was 2,183 (IQR 1,010-5,310) pg/mL. Overall, 155 (32.4%) patients had LVEF ≤40%. According to the DAPA-HF trial key criteria, 90 patients (18.8%) would be eligible for dapagliflozin. The remainder would be excluded due to LVEF >40% (67.6%), eGFR <30 mL/min/1.73 m2 (19.4%), NT-proBNP below the cutoff (16.7%), and/or SBP <95 mm Hg (6.5%). If we center the analysis to those with LVEF ≤40%, 58.1% would be eligible for dapagliflozin. The remainder would be excluded due to an eGFR <30 mL/min/1.73 m2 (20%), NT-proBNP below the cutoff (16.1%), and/or SBP <95 mm Hg (8.4%). CONCLUSION: Roughly half of our real-world HFrEF cohort would be eligible for dapagliflozin according to the key criteria of the DAPA-HF trial. The main reason for non-eligibility was an eGFR <30 mL/min/1.73 m2. However, two-thirds of patients had LVEF >40%. These findings show that dapagliflozin is a promising complementary new drug in the therapeutic armamentarium of most patients with HFrEF, while highlighting the urgent need for disease-modifying drugs in mid-range and preserved LVEF and the need to assess the efficacy and safety of SLGT2i in advanced kidney disease patients. The results of ongoing SGLT2i trials in these LVEF subgroups are eagerly awaited.
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Diabetes Mellitus Tipo 2 , Insuficiência Cardíaca , Idoso , Compostos Benzidrílicos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Glucosídeos , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/epidemiologia , Humanos , Masculino , Estudos Retrospectivos , Volume Sistólico , Função Ventricular EsquerdaRESUMO
BACKGROUND: The use of 3D printing of hydrogels as a cell support in bio-printing of cartilage, organs and tissue has attracted much research interest. For cartilage applications, hydrogels as soft materials must show some degree of rigidity, which can be achieved by photo- or chemical polymerization. In this work, we combined chemical and UV laser polymeric cross-linkage to control the mechanical properties of 3D printed hydrogel blends. Since there are few studies on UV laser cross-linking combined with 3D printing of hydrogels, the work here reported offered many challenges. METHODS: Polyethylene glycol diacrylate (PEGDA), sodium alginate (SA) and calcium sulphate (CaSO4) polymer paste containing riboflavin (vitamin B2) and triethanolamine (TEOHA) as a biocompatible photoinitiator was printed in an extrusion 3D plotter using a coupled UV laser. The influence of the laser power on the mechanical properties of the printed samples was then examined in unconfined compression stress-strain tests of 1 × 1 × 1 cm3 sized samples. To evaluate the adhesion of the material between printed layers, compression measurements were performed along the parallel and perpendicular directions to the printing lines. RESULTS: At a laser density of 70 mW/cm2, Young's modulus was approximately 6 MPa up to a maximum compression of 20% in the elastic regime for both the parallel and perpendicular measurements. These values were within the range of biological cartilage values. Cytotoxicity tests performed with Vero cells confirmed the cytocompatibility. CONCLUSIONS: We printed a partial tracheal model using optimized printing conditions and proved that the materials and methods developed may be useful for printing of organ models to support surgery or even to produce customized tracheal implants, after further optimization.
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The composition and architecture of a scaffold determine its supportive role in tissue regeneration. In this work, we demonstrate the feasibility of obtaining a porous electrospun fibrous structure from biodegradable polyurethanes (Pus) synthesized using polycaprolactone-diol as soft segment and, as chain extenders, chitosan (CS) and/or dimethylol propionic acid. Fourier transform infrared spectroscopy and proton nuclear magnetic resonance confirmed the syntheses. Fibre mats' properties were analysed and compared with those of solvent cast films. Scanning electron microscopy images of the electrospun scaffolds revealed fibres with diameters around 1⯵m. From tensile tests, we found that Young's modulus increases with CS content and is higher for films (2.5â¯MPa to 6.5â¯MPa) than for the corresponding fibre mats (0.8â¯MPa to 3.2â¯MPa). The use of CS as the only chain extender improves recovery ratio and resilience. From X-ray diffraction, a higher crystalline degree was identified in fibre mats than in the corresponding films. Films' wettability was enhanced by the presence of CS as shown by the decrease of water contact angle. X-ray photoelectron spectroscopy revealed that while ester groups are predominant at the films' surface, ester and urethanes are present in similar concentrations at fibres' surface, favouring the interaction with water molecules. Both films and fibres undergo hydrolytic degradation. In vitro evaluation was performed with human dermal fibroblasts. No PU sample revealed cytotoxicity. Cells adhered to fibre mats better than to films and proliferation was observed only for samples of CS-containing PUs. Results suggest that electrospun fibres of CS-based polyurethanes are good candidate scaffolds for soft tissue engineering.
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Quitosana/química , Fibroblastos/citologia , Poliuretanos/química , Alicerces Teciduais/química , Ureia/análogos & derivados , Ureia/química , Varredura Diferencial de Calorimetria , Adesão Celular , Proliferação de Células , Dimetilformamida/química , Furanos/química , Humanos , Hidroxiácidos/química , Teste de Materiais , Espectroscopia Fotoeletrônica , Poliuretanos/síntese química , Propionatos/química , Solventes/química , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Difração de Raios XRESUMO
Klebsiella pneumoniae invasive syndrome (KPIS) is a rare clinical condition characterized by primary liver abscess associated with metastatic infection. Most case reports are from Southeast Asia, with only one case described in Portugal. The Authors present the case of a 44-year-old man with a history of fever, dry cough and cervicalgia. A thoracic computed tomography (CT) scan showed multiple pulmonary and hepatic nodules, suggestive of metastatic malignancy. Both blood cultures and bronchoalveolar lavage were positive for Klebsiella pneumoniae. Imaging studies were repeated during his hospital stay, showing a reduction in both number and volume of identified lesions, thus revealing their infectious nature. This case illustrates how much this entity can mimic other illnesses. LEARNING POINTS: Klebsiella pneumoniae invasive syndrome is emerging as a global disease.The imaging-led diagnosis of neoplasia was proved incorrect and could have been deleterious for the patient.The lack of diagnostic suspicion can lead to shorter antibiotic treatment regimens, therefore compromising the patient's full recovery.