Oxidative stress promotes cytotoxicity in human cancer cell lines exposed to Escallonia spp. extracts.

BACKGROUND: Standard cancer treatments show a lack of selectivity that has led to the search for new strategies against cancer. The selective elimination of cancer cells modulating the redox environment, known as "selective oxycution", has emerged as a viable alternative. This research focuses on characterizing the unexplored Escallonia genus plant extracts and evaluating their potential effects on cancer's redox balance, cytotoxicity, and activation of death pathways. METHODS: 36 plant extracts were obtained from 4 different species of the Escallonia genus (E. illinita C. Presl, E. rubra (Ruiz & Pav.) Pers., E. revoluta (Ruiz & Pav.) Pers., and E. pulverulenta (Ruiz & Pav.) Pers.), which were posteriorly analyzed by their phytoconstituents, antioxidant capacity, and GC-MS. Further, redox balance assays (antioxidant enzymes, oxidative damage, and transcription factors) and cytotoxic effects (SRB, ∆Ψmt, and caspases actives) of those plant extracts were analyzed on four cell lines (HEK-293T, MCF-7, HT-29, and PC-3). RESULTS: 36 plant extracts were obtained, and their phytoconstituents and antioxidant capacity were established. Further, only six extracts had EC50 values < 10 µg*mL- 1, indicating high toxicity against the tested cells. From those, two plant extracts were selective against different cancer cell lines: the hexane extract of E. pulverulenta´s stem was selective for HT-29, and the ethyl acetate extract of E. rubra´s stem was selective for PC-3. Both extracts showed unbalanced redox effects and promoted selective cell death. CONCLUSIONS: This is the first study proving "selective oxycution" induced by Chilean native plant extracts.

Mechanical properties, in vitro and in vivo biocompatibility analysis of pure iron porous implant produced by metal injection molding: A new eco-friendly feedstock from natural rubber (Hevea brasiliensis).

Metal injection molding (MIM) has become an important manufacturing technology for biodegradable medical devices. As a biodegradable metal, pure iron is a promising biomaterial due to its mechanical properties and biocompatibility. In light of this, we performed the first study that manufactured and evaluated the in vitro and in vivo biocompatibility of samples of iron porous implants produced by MIM with a new eco-friendly feedstock from natural rubber (Hevea brasiliensis), a promisor binder that provides elastic property in the green parts. The iron samples were submitted to tests to determine density, microhardness, hardness, yield strength, and stretching. The biocompatibility of the samples was studied in vitro with adipose-derived mesenchymal stromal cells (ADSCs) and erythrocytes, and in vivo on a preclinical model with Wistar rats, testing the iron samples after subcutaneous implant. Results showed that the manufactured samples have adequate physical, and mechanical characteristics to biomedical devices and they are cytocompatible with ADSCs, hemocompatible and biocompatible with Wistars rats. Therefore, pure iron produced by MIM can be considered a promising material for biomedical applications.

Bile duct ligature in young rats: A revisited animal model for biliary atresia.

Biliary atresia leads to cirrhosis in the vast majority of patients and constitutes the first cause of paediatric liver transplantation. Animal models allow us to understand the molecular basis and natural history of diseases. The aim of this study is to describe a surgically created animal model of biliary atresia with emphasis in long-term liver function. Forty-two 3-week-old Sprague-Dawley rats were randomly divided into two groups: bile duct ligature (BDL) and control. The animals were sacrificed on the 2nd, 4th, and 6th postoperative weeks. Blood samples were collected for liver function analysis. The spleen to body weight ratio was determined. Histopathological examination of liver tissue was performed by hematoxylin-eosin and Sirius red staining. Collagen quantification was determined by using colorimetric digital image analysis and was expressed as a percentage of total liver tissue area. Quantitative real-time polymerase chain reaction was performed to analyse gene expression levels of transforming growth factor-ß1 (Tgfb1) and apeline (Apln) genes. Statistical analysis was performed where P<0.05 was considered significant. Animals from BDL group developed increasing cholestasis with clinical and laboratory features. Splenomegaly was detected at 4th and 6th week (P<0.05). Histological evaluation of the liver showed ductular reaction, portal fibrosis and bile plugs. Collagen area to total liver tissue area had a median of 2.5% in the control group and 6.5 %, 14.3 % and 37.7 % in BDL rats at 2nd, 4th and 6th weeks respectively (P<0.001). Tgfb1 mRNA expression level was significantly higher at 6th week (P<0.001) in BDL group when compared to control. Apln mRNA expression level was significantly higher at 4th and 6th week (P<0.001) and showed a positive linear correlation (r = 0.975, P<0.05) in BDL group when compared to control. Bile duct ligature in young rats is an animal model that recreates clinical, laboratory, histological and molecular findings of biliary atresia. Bile duct ligature constitutes a good animal model to investigate therapeutic approaches for modifying the progression of liver fibrosis in biliary atresia.

Invaginaciones intestinales en adultos: la visión del radiólogo.

Intussusception is rare in adults and has different characteristics from intussusceptions of children. Its clinical manifestations are varied and often nonspecific, requiring a high index of suspicion for diagnosis. Within the study methods, computed tomography has become fundamental in the study of abdominal pain. This has a high sensitivity and specificity for the diagnosis of intussusception. Most of the time the treatment is surgical, and succeeded in identifying the underlying lesions. We review the basics concepts, pathophysiology, imaging findings and frequent etiologies that can cause intussusception in adults.

Projeto, fabricação e avaliação de implantes craniofaciais personalizados: proposta de utilização de materiais combinados / Design, production and evaluation of customized craniofacial implants: an approach on the use of different materials

Um material adequado para a reconstrução óssea craniofacial deve ser simples de implantar, possuir forma adequada, resistência à fratura e à deformação similares ao osso original, ser eventualmente substituído por osso natural, ser largamente disponível e não possuir um custo muito elevado. Baseado no fato de que um material com todas estas características ainda não está disponível atualmente, torna-se importante buscar novos materiais, novas composições e novas conformações. Diferentes biomateriais são utilizados atualmente para cirurgias de reconstrução craniofacial, cada um apresentando suas vantagens e limitações. Entre eles destacam-se o titânio, o polimetilmetacrilato e os cimentos de fosfato de cálcio. O titânio apresenta difícil conformação; o polimetilmetacrilato polimeriza-se por meio de uma reação exotérmica, podendo causar necrose de tecidos adjacentes ao implante; o cimento de fosfato de cálcio, por sua vez apresenta certa fragilidade, característica de alguns materiais cerâmicos. Neste sentido, este estudo examinou diferentes materiais utilizados para reconstrução craniofacial e suas propriedades mecânicas quando submetidos a ensaios de flexão, como o polimetilmetacrilato, o cimento de fosfato de cálcio e o cimento de fosfato de cálcio reforçado com titânio. Foi verificada a melhoria de propriedades mecânicas do cimento de fosfato de cálcio quando reforçado com malha de titânio. Além disso, este estudo apresenta uma técnica para o projeto e fabricação de implantes craniofaciais personalizados utilizando cimento de fosfato de cálcio reforçado com titânio, validada através de quatro casos de indicação cirúrgica de reconstrução craniofacial.

A material suitable for craniofacial reconstruction must be easy to implant, have the appropriate shape, have the strength and deformation similar to the original bone, be eventually substituted for natural bone, be widely available and present affordable costs. As such as material, with all theses characteristics is still not available, it is important to search for new materials, new compositions and new design. Different biomaterials are used nowadays for craniofacial reconstruction surgeries, each one presenting its advantages and limitations. Among these materials are the titanium, the poli(methilmetacrilate) and the calcium phosphate cements. Titanium presents hard conformation; poli(methilmetacrilate)’s polymerization reaction is exothermic, which may cause necrosis of the adjacent tissues; calcium phosphate cement is brittle, an usual characteristic of ceramic materials. In this way, this study evaluated different materials used for craniofacial reconstruction and its mechanical properties when submitted to bending test, such as poli(methilmetacrilate), calcium phosphate cement and calcium phosphate cement reinforced with titanium. It was verified the improvement in the mechanical properties of the calcium phosphate cement when reinforced with titanium mesh. In addition, this study presents a method for design and manufacturing of customized craniofacial implants using calcium phosphate cement reinforced with titanium mesh, validated through four cases of craniofacial reconstruction surgery indication.