Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Corpos estranhos caminham pelo corpo em direção ao coração? Do foreign bodies migrate through the body towards the heart?

A fixação dos CE, principalmente os pontiagudos, favorece a migração pelo corpo, gerando a expressão popular: "os CEs caminham pelo corpo em direção ao coração". OBJETIVO: Descrever os mecanismos envolvidos na migração do CE e a forma de diagnosticá-los. METODOLOGIA: Numa população de 3.000 casos de corpos estranhos, em 40 anos, foram analisados quatro que tiveram deslocamento extraluminal. Foram tomados os dados clínicos, radiológicos, endoscópicos e ultrassonográficos coletadas no serviço de documentação médica. RESULTADOS: São apresentadas três histórias clínicas em que o CE era de espinha de peixe e uma de cartilagem de peixe. Em todos se analisou o deslocamento. Em dois a migração se iniciou no esôfago, um para a aorta e outro para a região cervical e nos dois outros, o deslocamento ocorreu a partir da faringe: um para a fáscia pré-vertebral e outro se exteriorizou na região submandibular. Discutem os mecanismos pelos quais ocorre a migração dos CEs pelo corpo e os riscos que tais deslocamentos promovem para o paciente e a forma de diagnosticá-los. CONCLUSÕES: Os CE podem caminhar pelo corpo, porém não para o coração. Em casos de histórias arrastadas de ingestão de CEs, o estudo por imagens se faz obrigatório, previamente ao exame endoscópico.<br>Fixation of foreign bodies (FB), in the mucosa, can favor its migration, giving origin to the popular saying: "FB walk to the heart". AIM: describe the mechanisms involved in FB migration and how to diagnose them. METHODOLOGY: From a sample of 3,000 foreign bodies, during 40 years, we analyzed four which had extra-lumen migration. We analyzed clinical, radiologic, endoscopic and ultrasound data collected at the medical documentation service. RESULTS: three clinical histories are presented, describing two fish bones and one piece of fish cartilage. FB shifting was analyzed in all of them. Migration started in the esophagus in two, one going to the aorta and the other to the neck area. In the other two, migration started in the pharynx, and the FB moved towards the prevertebral fascia and the other externalized in the submandibular region. The mechanisms and the risks posed to the patient, by FB migration, and the way to diagnose them are hereby discussed. CONCLUSIONS: the study allows us to determine that FB can move through the body but not towards the heart. The study also serves as a warning sign: in cases of prolonged histories of FB ingestion, imaging studies are mandatory before endoscopic examination

Efeitos de dois tipos de treinamento de natação sobre a adiposidade e o perfil lipídico de ratos obesos exógenos Effects of two different types of swimming exercise on adiposity and lipid profile in rats with exogenous obesity

OBJETIVO: Investigar os efeitos do exercício de natação intermitente em relação ao exercício contínuo e ao sedentarismo, em ratos Wistar, após o desenvolvimento de obesidade exógena pela administração de uma dieta hiperlipídica palatável sobre: evolução do peso corporal, ingestão alimentar, adiposidade, percentual de gordura dos tecidos e perfil lipídico. MÉTODOS: Foram utilizados ratos adultos, mantidos em gaiolas individuais, com livre acesso a água e comida. O protocolo experimental incluiu: 1) desenvolvimento da obesidade exógena (3 semanas), os animais foram divididos em: P: sedentários alimentados com dieta padrão Primor® (n=8) e H: sedentários alimentados com dieta hiperlipídica (n=32); 2) tratamentos (8 semanas subseqüentes), os animais (n=24) passaram a receber dieta padrão e foram divididos em: sedentário; treinado contínuo e treinado intermitente. Treinamentos (5x semana): Contínuo (90 minutos/dia) e Intermitente (3x30min/dia). Os animais foram submetidos à eutanásia (3 e 8 semanas), sendo coletados os tecidos adiposos, o fígado e o sangue. Foram determinados a adiposidade e o percentual de gordura dos tecidos adiposos e do fígado, o ganho de peso corporal, o consumo alimentar e o perfil lipídico. RESULTADOS: A dieta hiperlipídica aumentou a adiposidade, o percentual de gordura acumulada no fígado e desenvolveu dislipidemias. A troca de dieta e os dois tipos de treinamento foram capazes de reverter o quadro de obesidade exógena. Contudo, o exercício intermitente foi mais eficiente na redução da adiposidade e de ganho de peso. CONCLUSÃO: Associados à dieta balanceada, os treinamentos aplicados neste estudo poderiam ser utilizados como estratégia no controle de peso e de dislipidemias, tanto em modelos experimentais quanto em seres humanos.<br>OBJECTIVE: The objective was to look into the effects of intermittent swimming against continuous exercise and inactivity in Wistar rats after they developed exogenous obesity though the consumption of a palatable fat-rich diet. The following was investigated: evolution of body weight, food intake, adiposity, fat percentage in tissues and lipid profile. METHODS: Adult rats were kept in individual cages with free access to food and water. The experimental protocol included: 1) development of exogenous obesity (3 weeks). The animals were divided into S - inactive animals fed the standard Primor® diet (n=8) and HF - inactive animals fed a high-fat diet (n=32); 2) Treatment (the 8 following weeks) - the animals (n=24) were given the standard diet and divided into an inactive group, a continuous training group and an intermittent training group. Training occurred 5 times per week and was either continuous (90 minutes per day) or intermittent (3 times 30 minutes per day). The animals were killed at 3 and 8 weeks and the fat tissues, the liver and the blood were collected. Adiposity, fat percentage of the fat tissues and liver, gain of body weight, food consumption and lipid profile were determined. RESULTS: The high-fat diet increased adiposity, percentage of fat in the liver, and induced dyslipidemias. Diet change and the two types of training were capable of reducing exogenous obesity. However, intermittent exercise was more efficient in reducing adiposity and preventing weight gain. CONCLUSION: When associated with a balanced diet, the trainings used in this study can be used as a strategy to control weight and dyslipidemias, both in experimental models and in human beings