ABSTRACT The present study evaluated the relationship between herbivory and leaf quality of three abundant tree species (Cupania oblongifolia Mart., Siparuna guianensis Aubl. and Xylopia sericea St. Hill.) in the understory of a eucalyptus plantation and an adjacent Atlantic Rainforest fragment. Herbivory differed among species, since X. sericea was less attacked, while C. oblongifolia and S. guianensis were more. The species showed similar herbivory patterns between the investigated areas (eucalyptus plantation versus forest), although X. sericea showed higher herbivory rates in the forest fragment. Fiber values (NDF, CEL and LIG) varied significantly among the species, being lower in S. guianensis. X. sericea, the species with the highest C/N ratio, higher concentrations of total phenols, smaller leaf area and higher trichome density, showed the lowest leaf herbivory rates, corroborating the hypothesis that herbivory is lower in species with lower nutritional quality and a greater set of leaf defense features.

The tinplate, used in the packaging sector and formed from a metal substrate, comprises a steel base which has undergone a surface treatment to produce a thin layer of FeSn2, a tin layer and an oxide tin layer. Currently, packaging using surface treatment is based on the use of chromates because these metals provide an excellent corrosion resistance. Nontoxic alternatives to pre-treatments have been developed in recent years to replace the chromate process. The aim of this work is to analyze the performance of a new hybrid organic-inorganic film obtained from sol-gel consisting of the alkoxide precursors 3-(Trimethoxysilylpropyl)methacrylate (TMSM) and tetraethoxysilane (TEOS) with the addition of cerium nitrate with the scanning vibrating electrode technique (SVET), and electrochemical and morphological characterizations. Moreover, the evolution of the corrosion of the substrate was evaluated to propose a mechanism of corrosion. The results showed a galvanic coupling between the Sn/SnO2 coat (cathode) and the defects exposed at the ferrous base (anode). The organic-inorganic hybrid film containing a cathodic corrosion inhibitor was able to retard the corrosion of the tinplate.

Nós investigamos as alterações funcionais e morfológicas em corações de ratos infartados, sob o paradigma de inibição da enzima conversora de angiotensina. O infarto do miocárdio foi produzido pela ligadura da artéria coronária esquerda e um grupo falso-operado serviu de controle para o experimento. Os ratos infartados receberam água normal com (grupo CAP) ou sem (grupo INF) captopril. A avaliação funcional foi feita através de eletro (ECG) e ecocardiografia (ECO) momentos antes e 21 dias depois da cirurgia. O ECG dos grupos INF e CAP foram similares e compatíveis com infarto cicatrizado após a cirurgia. As principais diferenças entre os grupos INF e CAP foram: a prevenção do aumento da onda P e a atenuação tanto do desvio do eixo de despolarização ventricular como da amplitude da onda Q no CAP comparado com o INF. O ECO revelou que o tratamento com captopril foi mais efetivo em melhorar o enchimento diastólico do que aumentar a função sistólica. A dilatação e a falência cardíaca congestiva foram observadas apenas no INF. Ambos os grupos infartados exibiram um tecido cicatricial no ventrículo esquerdo, mas no INF esta se mostrou maior do que no CAP (49.7 ±5.24 vs. 22.33 ±6.19 respectivamente). Estes dados sugerem que o sistema renina angiotensina produz alterações morfológicas e funcionais em corações de ratos infartados e que estas podem ser detectadas por exames não invasivos.

We investigated the morphologic and functional changes of infarcted rat hearts under a paradigm of angiotensinconverting enzyme inhibition. Myocardial infarction was induced by left coronary artery ligation and a control group (SHAM) underwent sham-operation. Infarcted rats received normal drinking water with (CAP group) or without (INF group) captopril. Functional assessment was performed by electro (ECG) and echocardiogram (ECHO) just before and 21 days after surgery. The ECG of INF and CAP showed similar values and resembled healed infarct after surgery. The most outstanding differences between INF and CAP were the prevention of the increase of P-wave and attenuation both in rightward deviation of the QRS axis and Q-wave amplitude in CAP compared with INF. The ECHO showed that captopril treatment improved the diastolic filling more than systolic performance. Cardiac dilatation and left congestive heart failure were observed only in INF. Both infarcted groups showed a scar tissue in the left ventricular wall, but the INF showed a higher scar area than CAP (49.7 ± 5.24 vs. 22.33 ± 6.19 respectively). These data suggest that the renin-angiotensin system induces morphologic and functional changes in post-infarcted rat hearts and which can be assessed by non-invasive exams.

A resistência a múltiplos fármacos é o principal obstáculo no tratamento de pacientes com câncer. O mecanismo responsável pela resistência múltipla mais bem caracterizado envolve a expressão do produto do gene MDR-1, a glicoproteína P. Entretanto, o processo de resistência tem fatores múltiplos. Estudos de mecanismos de resistência múltipla a fármacos têm dependido da análise de linhagens celulares tumorais que foram selecionadas e apresentam reatividade cruzada a uma ampla faixa de agentes anti-tumorais. Este trabalho caracteriza uma linhagem celular com múltipla resistência a fármacos, selecionada originalmente pela resistência ao alcalóide de Vinca vincristina e derivado da linhagem eritro-leucêmica K562. Esta linhagem celular, denominada Lucena 1, super-expressa a glicoproteína P e tem sua resistência revertida pelos quimio-sensibilizantes verapamil, trifluoperazina e ciclosporinas A, D e G. Ademais, demonstramos que o azul de metileno era capaz de reverter parcialmente a resistência nesta linhagem celular. Em contraste, o uso de 5-flúor-uracil aumentava a resistência de Lucena 1. Adicionalmente aos quimioterápicos, células Lucena 1 eram resistentes radiação ultra-violeta A e peróxido de hidrogênio e deixavam de mobilizar o cálcio intra-celular quando se usava tapsigargina. Mudanças no cito-esqueleto desta linhagem foram também observadas.

Multidrug resistance to chemotherapy is a major obstacle in the treatment of cancer patients. The best characterised mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein. However, the resistance process is multifactorial. Studies of multidrug resistance mechanisms have relied on the analysis of cancer cell lines that have been selected and present cross-reactivity to a broad range of anticancer agents. This work characterises a multidrug resistant cell line, originally selected for resistance to the Vinca alkaloid vincristine and derived from the human erythroleukaemia cell K562. This cell line, named Lucena 1, overexpresses P-glycoprotein and have its resistance reversed by the chemosensitisers verapamil, trifluoperazine and cyclosporins A, D and G. Furthermore, we demonstrated that methylene blue was capable of partially reversing the resistance in this cell line. On the contrary, the use of 5-fluorouracil increased the resistance of Lucena 1. In addition to chemotherapics, Lucena 1 cells were resistant to ultraviolet A radiation and hydrogen peroxide and failed to mobilise intracellular calcium when thapsigargin was used. Changes in the cytoskeleton of this cell line were also observed.