RESUMEN

Copper oxide (CuO) has been broadly used in different technological and biological applications. However, based on the literature review, there are few reports describing the synthesis of tungsten doped copper oxide and its biological applications, although CuO and W (tungsten) based nanomaterials have been reportedly already synthesized. In this study we synthesized novel CuO and CuO/W (at.1%, 2% and 4%) nanoparticles and explored their tungsten content-dependent bactericide activity. In order to obtain the materials, was used a co-precipitation method which is of low cost. The synthesized materials were characterized by x-ray diffraction (XRD); XRD results indicated that only the sample with at.1% of W presented pure Tenorite phase. Diffuse reflectance spectroscopy (DRS) allowed to obtain the band gap energy values; CuO/W (at.2%) sample exhibited the minimum value of 2.62 eV. Grains sizes ranging from 39.78 to 53.47 nm were established through field emission-scanning electronic microscopy (FE-SEM), and these sizes were confirmed by transmission electron microscopy (TEM). Doping with W also influenced the morphology obtained in all cases. BET (Brunauer, Emmett, Teller) analysis allowed to establish an increase in specific surface area and pore size with W doping. The particle size was determined by dynamic light scattering (DLS). The bactericidal properties were tested using well diffusion method for Escherichia coli and Staphylococcus aureus bacteria. Bactericide response of CuO nanoparticles was improved by the inclusion of W dopant into the CuO structure, leading to an expansion in the inhibition zone for the CuO/W (at.1%) sample; inhibition halo diameters were 1.5 and 12 mm for CuO and CuO/W (at.1%), respectively. Hence, it was possible to infer the remarkable importance of the crystalline phase, morphology, particle size and specific superficial area of the CuO/W (at.1%) nanoparticles in its bactericide performance. WO3 secondary phase affected the bactericide response of the materials obtained at at.2% and at.4% of tungsten content.

Asunto(s)

RESUMEN

Angiogenesis, the complex process of formation of new blood vessels from pre-existing blood vessels, which involves the participation of several pro- and anti-angiogenic factors, is implicated in many physiological and pathological conditions. Nanoparticle-based anti-angiogenic activity at the tumour tissue, harnessed by the Enhanced Permeability and Retention Effect (EPR effect), could potentially become a breakthrough therapy to halt tumour progression. Herein, we evaluate the anti-angiogenic effect of ZnWO4 nanoparticles (NPs). The nanoparticles were obtained by microwave-assisted hydrothermal synthesis (MAHS) at 120 °C for 60 min and were structurally characterised by X-ray diffraction (XRD) and micro-Raman (MR) spectroscopy. The mean size and polydispersity index were estimated by Zeta potential analysis. The XRD analysis revealed structural organisation at a long-range order, with an average crystallite size of around 3.67 nm, while MR revealed short-range order for ZnWO4. The anti-angiogenic potential of zinc tungstate nanoparticles was investigated through the chorioallantoic membrane assay (CAM) using fertilised chicken eggs. We demonstrate, in an unprecedented way, that nanocrystalline ZnWO4 NPs obtained by MAHS, at low reaction temperatures, showed excellent anti-angiogenic properties even at low concentrations. The ZnWO4 NPs were further evaluated for its cytotoxicity in vitro.

Asunto(s)

RESUMEN

The present study analyzed the action of sodium trimetaphosphate (TMP) and/or fluoride on hydroxyapatite. Hydroxyapatite powder was suspended in different solutions: deionized water, 500 µg F/mL, 1,100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL plus 1%TMP and 500 µg F/mL plus 3%TMP. The pH value of the solutions was reduced to 4.0 and after 30 min, raised to 7.0 (three times). After pH-cycling, the samples were analyzed by X-ray diffraction and infrared spectroscopy. The concentrations of calcium fluoride, fluoride, calcium and phosphorus were also determined. Adding 1% or 3% TMP to the solution containing 500 µg F/mL produced a higher quantity of calcium fluoride compared to samples prepared in a 1,100 µg F/mL solution. Regarding the calcium concentration, samples prepared in solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP were statistically similar and showed higher values. Using solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP resulted in a calcium/phosphorus ratio close to that of hydroxyapatite. It is concluded that the association of TMP and fluoride favored the precipitation of a more stable hydroxyapatite.

O presente estudo avaliou a ação do trimetafosfato de sódio (TMP) e/ou fluoreto sobre a hidroxiapatita. Pó de hidroxiapatita foi suspenso em diferentes soluções: água deionizada, 500 µg F/mL, 1100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL adicionado a 1%TMP e 500 µg F/mL associado a 3%TMP. O pH das soluções foi reduzido para 4,0 e depois de 30 min, elevado para 7,0 (três vezes). Depois do processo de ciclagem de pH, as amostras foram analisadas por difração de raios-X e espectroscopia por infravermelho. As concentrações de fluoreto de cálcio, fluoreto, cálcio e fósforo também foram determinadas. A adição de 1% ou 3% TMP na solução contendo 500 µg F/mL produziu uma maior quantidade de fluoreto de cálcio comparado às amostras tratadas com uma solução de 1100 µg F/mL. A respeito da concentração de cálcio, amostras tratadas com soluções de 1100 µg F/mL e 500 µg F/mL adicionado ao TMP foram estatisticamente similares e mostraram maiores valores. Soluções de 1100 µg F/mL e 500 µg F/mL adicionado ao TMP resultaram em uma proporção molar Ca/P mais próxima à da hidroxiapatita. Conclui-se que a associação de TMP e F favoreceu a precipitação de uma hidroxiapatita mais estável.

Asunto(s)

RESUMEN

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat. (AU)

Asunto(s)

RESUMEN

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat.

Asunto(s)

RESUMEN

Testicular estrogen receptors were measured in the presence of phosphatase inhibitors, molybdate (MoO4=), wolframate (WO4=) and fluoride (F-), under different experimental conditions. At 0-4 degrees C, MoO4= was able to partially replace the stabilizing action of dithiothreitol (DTT) on cytosolic estrogen binding activity, suggesting a protective effect on reduced sulfhydryl groups. At 25 degrees C in the presence of DTT, the effect of MoO4= was observed in homogenates and low speed supernatants, being uneffective in cytosol. A possible mechanism of action through inhibition of phosphatase activity was supported by the use of WO4=. Acid phosphatase activity was inhibited in the presence of these agents, whereas alkaline phosphatase was unaffected. The addition of MoO4= also caused a significant inhibition of proteolytic activity. These results suggest that MoO4= would stabilize testicular estrogen binding activity through, at least, three mechanisms: 1) protection of reduced sulfhydryl groups; 2) inhibition of acid phosphatase, and 3) inhibition of proteolytic activity.

Asunto(s)

RESUMEN

Se determinaron receptores estrogénicos testiculares en presencia de inhibidores de fosfatasas, molibdato (Mo04), wolframato (W04) y fluoruro (F-), bajo diferentes condiciones experimentales. A 0-4-C el Mo04 mimetizó parcialmente la acción estabilizadora del ditiotreitol (DTT) sobre la unión del estrógeno a su receptor citosólico, sugiriendo un efecto protector sobre los grupos sulfhidrilo reducidos. Por otra parte, a 25-C, en presencia de DTT, el efecto de Mo04 fue observado en homogenato y sobrenadante de baja velocidad, pero no se evidenció en citosol. Un posible mecanismo protector de la actividad de unión basado en la inhibición de la actividad de fosfatasas fue corroborado mediante el uso de W04. La actividad fosfatasa ácida resultó inhibida por estos agentes, mientras que la fosfatasa alcalina no presentó modificaciones. El agregado de Mo04 y W04, provocó, además, una inhibición siginificativa de la actividad proteolítica. Estos resultados sugieren que el Mo04 podría estabilizar la unión de estrógenos a sus receptores testiculares, a través de tres posibles mecanismos: 1) protección de grupos sulfhidrilo reducidos; 2) inhibición de la fosfatasa ácida y 3) inhibición de la actividad protelítica

Asunto(s)

RESUMEN

Se determinaron receptores estrogénicos testiculares en presencia de inhibidores de fosfatasas, molibdato (Mo04), wolframato (W04) y fluoruro (F-), bajo diferentes condiciones experimentales. A 0-4-C el Mo04 mimetizó parcialmente la acción estabilizadora del ditiotreitol (DTT) sobre la unión del estrógeno a su receptor citosólico, sugiriendo un efecto protector sobre los grupos sulfhidrilo reducidos. Por otra parte, a 25-C, en presencia de DTT, el efecto de Mo04 fue observado en homogenato y sobrenadante de baja velocidad, pero no se evidenció en citosol. Un posible mecanismo protector de la actividad de unión basado en la inhibición de la actividad de fosfatasas fue corroborado mediante el uso de W04. La actividad fosfatasa ácida resultó inhibida por estos agentes, mientras que la fosfatasa alcalina no presentó modificaciones. El agregado de Mo04 y W04, provocó, además, una inhibición siginificativa de la actividad proteolítica. Estos resultados sugieren que el Mo04 podría estabilizar la unión de estrógenos a sus receptores testiculares, a través de tres posibles mecanismos: 1) protección de grupos sulfhidrilo reducidos; 2) inhibición de la fosfatasa ácida y 3) inhibición de la actividad protelítica (AU)

Asunto(s)