ABSTRACT Purpose: To study the influence of silver nanoparticles (AgNP) on tissue reaction when incorporated into a polymeric matrix of polyacrylic acid-based (Carbopol®) gel as a proposal for a new low-cost type of biomaterial that is simple to manufacture for use as an antimicrobial and antioxidative dressing. Methods: In-vivo tests of implantation in the subcutaneous tissue of the back of rats were performed using polyethylene tubes in three situations: empty, only the gel, and gel incorporated with AgNP. Then, the tissue reaction was studied by counting inflammatory cells. Additionally, in-vitro tests of the antioxidative and antimicrobial activity of AgNP were performed. The radical 2,2 diphenyl-1 picrylhydrazyl (DPPH) was used to test the antioxidative activity of AgNP using electron spin resonance. The antimicrobial activity of AgNP was determined by minimum inhibitory concentration against the microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Results: The results indicated that AgNP presents antioxidative activity and was able to inhibit the growth of the microorganisms tested. The addition of AgNP in Carbopol® did not alter the tissue inflammatory response (p>0.05, Kruskal-Wallis’s test). Conclusions: The new biomaterial is promising for future use as a dressing for its beneficial properties for regenerative processes.

Abstract In this work, the natural latex extracted from Harconia speciosa was incorporated with silver nanoparticles (AgNP) to compose a functional biomaterial associating the intrinsic angiogenic activity of the latex and the antimicrobial activity of AgNP. Tissue reaction after subcutaneous implantation in dorsum of rats of membranes without AgNP and with 0.05%, 0.4% AgNP was compared at 3, 7 and 25 days. No statistically significant difference in the tissue response of the different biomaterials was observed, indicating that AgNP did not interfere with the inflammatory reaction (p > 0.05) or with the angiogenic activity of latex. Biomembranes were also tested against bacterial biofilm formation by Staphylococcus aureus and the antimicrobial activity of the new biomaterial can be found with bacteria crenation (0.05% AgNP) and no biofilm deposition (0.4% AgNP). Therefore, this biomaterial has interesting properties for the tissue repair process and may be feasible for future applications as dressing.

Resumo A poluição de ambientes aquáticos em decorrência de atividades antrópicas negativas permanece sendo um grande problema. Para se obter conhecimento acerca dos níveis biológicos de poluentes disponíveis no meio, os bioindicadores tornam-se uma ferramenta muito útil no auxílio das análises químicas da água que primariamente descrevem a total concentração do respectivo poluente. Nesse contexto, o objetivo desse trabalho foi o de empregar a técnica de Espectroscopia de Ressonância do Spin Eletrônico (ESR) para detectar a presença de poluentes, diretamente em espécimes de Neoechinorhynchus curemai e nos tecidos do seu hospedeiro Prochilodus lineatus, assim também como na água e sedimento do rio Batalha, no mesmo ponto onde os peixes foram coletados. A análise do espectro das amostras identificou a presença de três metais (Cu2+, Fe3+ e Mn2+), além do óxido nítrico (NO) e do ácido húmico (AH). A quantificação dos elementos nas amostras só foi possível para o Cu, detectado no espectro dos parasitos, que foi de 2ppm. A ESR se mostrou eficiente na detecção de íons metálicos de transição (Cu2+, Fe3+ e Mn2+), além do NO e do AH. Entretanto, a baixa concentração desses compostos nos tecidos (fígado, músculo e intestino) de P. lineatus. não possibilitaram sua quantificação, já que as concentrações dos mesmos estão abaixo do limite de detecção do aparelho. É possível concluir que N. curemai teve a capacidade de acumular esses íons, especialmente cobre.

Abstract Aquatic environmental pollution due to negative human activities remains a major problem. Bioindicators that primarily describe the total concentration of the respective pollutant are very useful tools to aid in the chemical analysis of water in order to obtain knowledge about the levels of pollutants in the environment. This study therefore used Electron Spin Resonance Spectroscopy (ESR) to detect the presence of transition metals (copper, iron and manganese) and possible radicals present in samples of Neoechinorhynchus curemai and its host tissues Prochilodus lineatus, as well in water and sediment of the Batalha River, at the same sample site where fish were collected. Spectral analysis of samples showed the presence of three metals (Cu2+, Fe3+ and Mn2+), in addition to nitric oxide (NO) and humic acid (HA). Quantification of the elements in the samples was possible only for Cu detected in the spectrum of parasites, which was equivalent to 2 ppm. ESR proved to be efficient in the detection of transition-metal ions (Cu2+, Fe3+ and Mn2+), in addition to NO and HA. However, the low concentration values of these compounds in P. lineatus tissues (liver, muscle and intestine) and in the water and sediment samples collected did not allow their quantification, as they were below the limit of detection. It can be concluded that N. curemai had the capacity to accumulate these ions, especially copper.

RESUMO Este trabalho relata a datação de um dente humano e concha fóssil encontrados no sítio arqueológico Toca do Enoque, localizado no Parque Nacional da Serra das Confusões (Piauí, Brasil), onde muitas pinturas pré-históricas foram encontradas. Durante uma escavação arqueológica, três enterramentos com esqueletos humanos e algumas conchas foram encontrados. Para a determinação da dose equivalente recebida por cada amostra, as medidas de Espectroscopia por Ressonância do Spin Eletrônico (ESR) para as datações do dente e da concha foram realizadas de forma independente por dois laboratórios brasileiros, em Ribeirão Preto (USP) e em Recife (UFPE). As idades obtidas para o dente e a concha por ambos os laboratórios são semelhantes (~ 4.8kyBP). Estes resultados estão de acordo com a datação por C-14 da concha e outras amostras (carvão) encontradas no mesmo sepultamento. Assim, este trabalho oferece uma comparação válida de resultados de datação por ESR de dois laboratórios independentes e entre dois métodos de datação, ou seja, C-14 e ESR com resultados que mostram a validade para a datação por ESR para essa faixa de idades.

ABSTRACT This work reports the dating of a fossil human tooth and shell found at the archaeological site Toca do Enoque located in Serra das Confusões National Park (Piauí, Brazil). Many prehistoric paintings have been found at this site. An archaeological excavation unearthed three sepulchers with human skeletons and some shells. Two Brazilian laboratories, in Ribeirão Preto (USP) and Recife (UFPE), independently performed Electron Spin Resonance (ESR) measurements to date the tooth and the shell and obtain the equivalent dose received by each sample. The laboratories determined similar ages for the tooth and the shell (~4.8 kyBP). The results agreed with C-14 dating of the shell and other samples (charcoal) collected in the same sepulcher. Therefore, this work provides a valid inter-comparison of results by two independent ESR-dating laboratories and between two dating methods; i.e., C-14 and ESR, showing the validity of ESR dating for this range of ages.

Ipomoea imperati (Vahl) Griseb., Convolvulaceae, is used in traditional medicine for the treatment of inflammation, swelling and wounds, as well as to treat pains and stomach problems. This work evaluates the anti-oxidative activity by ESR (Electron Spin Resonance spectroscopy) and the preventive and curative actions of I. imperati in gastric ulcer animal model. Ipomoea imperati (200 mg/kg, p.o.) prevented the formation of gastric lesions in 78% (p<0.05) when compared with the negative control tween 80. Lanzoprazole, prevented in 85% the gastric lesions formation induced by ethanol (p<0.05). Therefore, the oral administration of I. imperati one hour before the ulcerogenic agent prevented the ulcer formation, conserving the citoprotection characteristics of the gastric mucosa and assuring the integrity of gastric glands and gastric fossets. The healing activity of I. imperati (200 mg/kg, p.o.) evaluated in chronic ulcer experiments induced by the acetic acid, was 72% (p<0.05). The positive control, ranitidine, healed 78% of the gastric lesions (p<0.05). The histological analysis confirmed the recovery of the mucosal layer and the muscle mucosal layer harmed by the acetic acid. Experiments in vitro with DPPH (2.2-diphenyl-1-picrylhydrazyl) of anti-oxidative activity demonstrated that I. imperati presents an IC50 of 0.73±0.01 mg/mL.

Este trabalho apresenta um estudo comparativo da atividade antioxidante dos extratos de nove espécies de plantas pertencentes à flora brasileira - Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis, Didymopanax venosum - neutralizando os radicais livres DPPH (2,2-difenil-1-picrilhidrazil) e TEMPOL (4-hidróxi-2,2,6,6-tetrametil-1-piperidiniloxi-1-oxil) utilizando ressonância paramagnética eletrônica (RPE), e agindo sobre os radicais hidroxila (OH•) gerados por uma reação Fenton, através da técnica de spin-trapping. Os melhores resultados foram obtidos para os extratos de Iryanthera juruensis e Chrysophyllum inornatum. Os resultados dos testes foram acompanhados por cálculos computacionais dos compostos, utilizando a teoria do funcional da densidade (TFD), com aproximação local da densidade (ALD), e o código SIESTA. Os resultados indicaram que a energia liberada na reação de redução TEMPOL é inferior a DPPH. Como o DPPH é um composto de menor custo e mais disponível tem um uso mais amplo que o TEMPOL, entretanto este último deve ser considerado quando se quer estudar processos que envolvam menores energias.

This work presents a comparative study of the antioxidant activity of extracts from nine plant species belonging to the Brazilian flora - Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis, Didymopanax venosum - acting on the free-radicals DPPH (2,2-diphenyl-1-picrylhydrazyl) and TEMPOL (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy-1-oxyl) by electron paramagnetic resonance (EPR), and acting on the hydroxyl radical (OH•) by the spin-trapping technique generated by a Fenton reaction. Results showed that the extracts of Iryanthera juruensis and Chrysophyllum inornatum display the strongest antioxidant activities. The results of scavenging tests were clarified by computational calculations - density functional theory (DFT), local density approximation (LDA) with SIESTA code - indicating that the energy released in the reduction reaction of TEMPOL is less than DPPH. Due to its availability and cost DPPH is more often used in these tests than TEMPOL, however TEMPOL should be considered when studying processes dealing with smaller energies.

O acúmulo de ferro na talassemia causa lesões orgânicas e reduz a sobrevida do paciente por lesão cardíaca na segunda década da vida, e tem sido avaliado por medidas diretas (biópsia) e indiretas (ferritina). As medidas isoladas carecem de valor, sendo preferidas as sequenciais. Este trabalho pretende comparar medidas indiretas de sobrecarga de ferro, uma medida da concentração de ferro hepático por ressonância magnética, e a ferritina sérica média dos últimos quatro anos. Trata-se de estudo retrospectivo de 25 pacientes do Centro Regional de Hemoterapia, em Ribeirão Preto, Brasil. Encontrou-se em vinte pacientes ferro hepático acima de 7 mg/g peso seco e ferritina média elevada acima de 2.500 ug/l em dez. Estratificação em três níveis de sobrecarga (leve, moderada e grave) produziu resultados semelhantes em ambos os testes. Vários outros fatores influenciam o grau de sobrecarga de ferro na talassemia. Não houve correlação significativa com aplicação de testes não-paramétricos. Ambos os métodos usados concomitantemente levarão a um melhor planejamento da terapia quelante.

Accumulation of iron in thalassemia causes organ damage and reduces patient survival due to heart lesions in the second decade of life. Iron deposits are monitored by direct (biopsy) and indirect methods (ferritin) with sequential data being better than isolated measurements. This paper compares two indirect measurements of iron overload; a single hepatic iron concentration (HIC) by magnetic resonance and mean ferritin levels over four years. A retrospective study of 25 patients from the Centro Regional de Hemoterapia in Ribeirão Preto, Brazil was carried out. High HIC (above 7 mg per gram of dry weight) was found in 20 patients and high mean serum ferritin (above 2500 μg/L) in 10 patients. Stratification into three levels (low, moderate and high) of iron overload gave similar results in both tests. Many other factors influence de degree of iron overload in thalassemia. No correlation was found using a non-parametric statistical test between HIC and mean serum ferritin. Both methods provide better planning of chelation therapy.

O aumento relativo do fluxo cerebral sangüíneo (relative Cerebral Blood Flow - rCBF) pode contribuir para uma mudança no sinal dependente da oxigenação do sangue (Blood Oxygenation Level Dependent - BOLD). O objetivo principal deste trabalho foi estudar alguns aspectos da alteração perfusional no cérebro humano em resposta a um estímulo uniforme: hipercapnia, causada por um estado de apnéia induzida. Foi observado um aumento global no sinal BOLD durante a hipercapnia. Este aumento é correlacionado com a duração da apnéia e mostra uma clara distinção entre a substância branca e cinzenta, sendo maior na substância cinzenta.

The increase of relative cerebral blood flow (rCBF) may contribute for a change in blood oxygenation level dependent signal (BOLD). The main purpose of this study is to investigate some aspects of perfusional alterations in the human brain in response to a uniform stimulation: hypercapnia induced by breath holding. It was observed that the BOLD signal increased globally during hypercapnia and that it is correlated with the time of breath holding. This signal increase shows a clear distinction between gray and white matter, being greater in the grey matter.

A simple system to measure the magnetic susceptibility of different materials is presented. The system uses an analytical scale with sensitivity on the order of micrograms and a permanent NdBFe magnet, based in the Rankine method. In this apparatus, the sample is placed near to the magnet that is fixed on the scale. Depending on the magnetic properties of the sample, an attractive or repulsive force will appear between the magnet and the magnetizing sample. Measuring this force, registered by the scale as a mass, the magnetic parameters such as: permeability and susceptibility of the sample can be determined. Despite it is simplicity the method is quantitative, precise and easily reproducible in many laboratories, what makes it attractive for teaching experiments.