Fabrication of electrospun scaffolds with cell laden hydrogel for cartilage tissue engineering

Tissue engineering strategies create artificial substitutes for the regeneration of damaged tissues, beginning with the fabrication of scaffolds moving then to cell incorporation onto those scaffolds and subsequent tissue growth in vitro. Cell seeding techniques, unfortunately, are usually ineffective to develop scaffolds with homogenous cell distribution, resulting in non-functional tissue formation [1]. With electrospun scaffolds, cell incorporation becomes even more challenging. Electrospun scaffolds are a very tightly packed layer of fibers with small pores, that makes difficult the migration of cells onto the scaffolds, as well as, the diffusion of nutrients and wastes. To overcome this drawback, the direct incorporation of cells, using electrospraying technique, onto the scaffolds during the electrospinning process has been reported. Cell electrospraying is a jet-based technique that allows the spray of living cells onto the materials by applying an electric charge in a cellular suspension [2]. Several studies have proved that cells can survive and proliferate after electrospraying process [3], [4]. Still, previous work has shown that while uniformly distributed cell-laden scaffolds can be fabricated using this technique, some issues remain. Cell desiccation on top of the fibers due to longer duration of the experiment and inadequate cell environment – low temperature and CO2 concentration – and solvent toxicity are the main limitations for the optimal efficiency of cell electrospray process onto electrospun fibers. In this regard, in this work, the production of electrospun scaffolds was combined with the electrospray of chondrocyte laden hydrogel creating a shield/protection around the cells during and after the electrospray process, preventing its dehydration. For that, a polymeric solution of polycaprolactone (PCL) and gelatin was electrospun alternately with a chondrocyte-laden sodium alginate hydrogel electrospray. Sodium alginate is a natural polymer widely used in biomedical engineering due to its biocompatibility, biodegradability and ability to form hydrogels [5]. The prepared scaffolds were then cultured for 7 days and the respective cell viability assessed. The percentage of viability was calculated as a ratio of the metabolic activity of the electrosprayed chondrocytes and the metabolic activity of chondrocytes that did not underwent any process. The chondrocyte distribution was also evaluated. On the first day of culture, the results showed that the cellular viability was higher than the one previous reported, demonstrating that the alginate hydrogel allowed the cells to survive and helps in its attachment. After 7 days of culture, cells continue alive with considerable viability increasing. It was also shown that it was possible to incorporate cells homogenously distributed by electrospraying process using the chondrocyte laden hydrogel. These results emphasize the potential value that the hydrogels can have on the electrospraying process with the electrospun scaffolds.publishe

Identifying a Cardiac Source of Embolism by Transesophageal Echocardiography: Review of a 12-Year Experience

INTRODUCTION: Peripheral embolism is frequently related to a cardiac source of embolism. Transesophageal echocardiography (TEE) is a useful tool for identifying such sources. OBJECTIVES: Our laboratory has gained wide experience in TEE, with a large number of exams performed to search for a cardiac source of embolism. We therefore thought it would be useful to present our experience in the last 12 years following the introduction of the technique. METHODS: This was a retrospective study of 1110 consecutive patients undergoing TEE to search for a cardiac source of embolism, after an embolic event and a transthoracic echocardiogram. RESULTS: The patients' mean age was 53 +/- 14 years, 52% male. There was peripheral embolism in 5% of cases and cerebral embolism in the remainder. The exam identified a potential embolic source in 35.6% of cases, the most frequent diagnoses being intracardiac shunt at the atrial level (9.5%), atrial septal aneurysm (ASA) (6.6%), intracardiac thrombi (6.4%) and atherosclerotic plaques in the thoracic aorta (9.6%). The presence of ASA was frequently associated with patent foramen ovale (27%), which was more frequent in younger patients. Overall, we identified a cardiac source of embolism more often in elderly patients, with a predominance of atherosclerotic plaques in the aorta. ETE was more frequently diagnostic in patients with peripheral embolism, but there were no differences in terms of etiology. CONCLUSIONS: TEE is very useful to search for cardiac sources of embolism, especially in younger patients, in whom causes potentially treatable surgically or percutaneously can be identified. In elderly patients, therapeutic strategy will probably not be changed by the findings (mostly thrombi and atherosclerotic plaques). The presence of ASA and embolic events makes it essential to perform a thorough search by TEE for intracardiac shunts, which are frequently associated

Groundwater quality in coast region, Piauí state, Brazil.

The water resource systems of the coastal region of the Piaui State, Brazil, are abundant and of high productivity, favoring the use of the underground water for several ends such as, human consumption, irrigation and local tourism. Problems caused by the inadequate handling of the soil and the utilization of unsafe wells, are some of the factors that contribute, directly or indirectly, to the maintenance of the environmental quality of these resources. This study aimed to obtain current information on the physical and chemical characteristics to evaluate the underground water quality in six locations of the coastal region. Samples of 54 public and private wells were collected during the 2004 and 2005 dry season. The results were interpolated in geographical information system (GIS). It was concluded that the north and east costal region were the ones that presented the highest salinity indexes, presenting great restrictions to human consumption and irrigation

Qualidade da água subterrânea para fins de irrigação na microrregião de Teresina, Piauí.

O presente estudo teve por objetivo a realização de um levantamento das características físicas, químicas e físico-químicas das águas subterrâneas da Bacia Sedimentar do Rio Parnaíba, em especial aquelas características relevantes para a determinação da qualidade dessas águas para fins de irrigação. Foram coletadas amostras de água em 270 poços georreferenciados localizados em 14 municípios da Microrregião de Teresina-PI. As amostras foram coletadas em duas épocas distintas, ou seja, nas estações secas de 2004 e de 2005. Nessas amostras foram realizadas determinações dos seguintes parâmetros: pH, NH4+, NO3-, Ca2+, Mg2+, CE, RAS, Na+, Cloretos, Bicarbonatos e Carbonatos. Os resultados foram interpolados em um SIG (Sistemas de Informações Geográficas) – SPRING – com o objetivo de constituir mapas temáticos mostrando as classes de restrição das águas para fins de irrigação. Dentre os resultados obtidos, a análise conjunta de RAS e CE revelou potenciais problemas de infiltração da água no solo em mais da metade dos municípios, mostrando a necessidade de um manejo adequado da irrigação com vistas a mitigar os problemas nessas áreas

Isochronous island bifurcations driven by resonant magnetic perturbations in Tokamaks

Recent evidences show that heteroclinic bifurcations in magnetic islands may be caused by the amplitude variation of resonant magnetic perturbations in tokamaks. To investigate the onset of these bifurcations, we consider a large aspect ratio tokamak with an ergodic limiter composed of two pairs of rings that create external primary perturbations with two sets of wave numbers. An individual pair produces hyperbolic and elliptic periodic points, and its associated islands, that are consistent with the Poincar\'e-Birkhoff fixed point theorem. However, for two pairs producing external perturbations resonant on the same rational surface, we show that different configurations of isochronous island chains may appear on phase space according to the amplitude of the electric currents in each pair of the ergodic limiter. When one of the electric currents increases, isochronous bifurcations take place and new islands are created with the same winding number as the preceding islands. We present examples of bifurcation sequences displaying (a) direct transitions from the island chain configuration generated by one of the pairs to the configuration produced by the other pair, and (b) transitions with intermediate configurations produced by the limiter pairs coupling. Furthermore, we identify shearless bifurcations inside some isochronous islands, originating nonmonotonic local winding number profiles with associated shearless invariant curves

Broadening Risk Factor or Disease Definition as a Driver for Overdiagnosis: A Narrative Review

Medical overuse-defined as the provision of health services for which potential harms exceed potential benefits-constitutes a paradigm of low-value care and is seen as a threat to the quality of care. Value in healthcare implies a precise definition of disease. However, defining a disease may not be straightforward since clinical data do not show discrete boundaries, calling for some clinical judgment. And, if in time a redefinition of disease is needed, it is important to recognize that it can induce overdiagnosis, the identification of medical conditions that would, otherwise, never cause any significant symptoms or lead to clinical harm. A classic example is the impact of recommendations from professional societies in the late 1990s, lowering the threshold for abnormal total cholesterol from 240 mg/dl to 200 mg/dl. Due to these changes in risk factor definition, literally overnight there were 42 million new cases eligible for treatment in the United States. The same happened with hypertension-using either the 2019 NICE guidelines or the 2018 ESC/ECC guidelines criteria for arterial hypertension, the proportion of people overdiagnosed with hypertension was calculated to be between 14% and 33%. In this review, we will start by discussing resource overuse. We then present the basis for disease definition and its conceptual problems. Finally, we will discuss the impact of changing risk factor/disease definitions in the prevalence of disease and its consequences in overdiagnosis and overtreatment (a problem particularly relevant when definitions are widened to include earlier or milder disease).info:eu-repo/semantics/publishedVersio

Screening of natural Wolbachia infection in mosquitoes (Diptera: Culicidae) from the Cape Verde islands

Funding Information: We are grateful to the National Institute of Public Health for the laboratory support in Cape Verde, and to technicians from the Ministry of Health for their assistance in field work. We would like to thank Prof. Paulo Almeida for providing DNA controls of Cx. pipiens and Cx. quinquefasciatus used in the species identification PCR assay. Funding Information: This work was funded by national funds through FCT—Fundação para a Ciência e Tecnologia, I.P., within the framework of the project ARBOMONITOR (PTDC/BIA-OUT/29477/2017. Aires da Moura was funded by the Ph.D. fellowship program of Camões I.P. Publisher Copyright: © 2023, The Author(s).Background: Wolbachia pipientis is an endosymbiont bacterium that induces cytoplasmic incompatibility and inhibits arboviral replication in mosquitoes. This study aimed to assess Wolbachia prevalence and genetic diversity in different mosquito species from Cape Verde. Methods: Mosquitoes were collected on six islands of Cape Verde and identified to species using morphological keys and PCR-based assays. Wolbachia was detected by amplifying a fragment of the surface protein gene (wsp). Multilocus sequence typing (MLST) was performed with five housekeeping genes (coxA, gatB, ftsZ, hcpA, and fbpA) and the wsp hypervariable region (HVR) for strain identification. Identification of wPip groups (wPip-I to wPip-V) was performed using PCR–restriction fragment length polymorphism (RFLP) assay on the ankyrin domain gene pk1. Results: Nine mosquito species were collected, including the major vectors Aedes aegypti, Anopheles arabiensis, Culex pipiens sensu stricto, and Culex quinquefasciatus. Wolbachia was only detected in Cx. pipiens s.s. (100% prevalence), Cx. quinquefasciatus (98.3%), Cx. pipiens/quinquefasciatus hybrids (100%), and Culex tigripes (100%). Based on the results of MLST and wsp hypervariable region typing, Wolbachia from the Cx. pipiens complex was assigned to sequence type 9, wPip clade, and supergroup B. PCR/RFLP analysis revealed three wPip groups in Cape Verde, namely wPip-II, wPip-III, and wPip-IV. wPip-IV was the most prevalent, while wPip-II and wPip-III were found only on Maio and Fogo islands. Wolbachia detected in Cx. tigripes belongs to supergroup B, with no attributed MLST profile, indicating a new strain of Wolbachia in this mosquito species. Conclusions: A high prevalence and diversity of Wolbachia was found in species from the Cx. pipiens complex. This diversity may be related to the mosquito's colonization history on the Cape Verde islands. To the best of our knowledge, this is the first study to detect Wolbachia in Cx. tigripes, which may provide an additional opportunity for biocontrol initiatives. publishersversionpublishe