Effect of target/filter combination on the mean glandular dose and contrast-detail threshold: A phantom study.

INTRODUCTION: In mammography it is essential to combine aspects of image quality with compliance with glandular dose levels. The objective of this study was to combine the assessment of the contrast-detail threshold and the mean glandular dose for different target/filter combinations in digital mammography and to indicate the optimal combination through a figure of merit (FOM). METHODS: In a direct digital mammograph, performance and image quality standards were evaluated using a solid-state multidetector capable of measuring various parameters including kerma and standardized phantoms for image quality. After verifying the proper functioning of the mammograph, the contrast-detail detection threshold and the mean glandular dose values for thicknesses ranging from 20 mm to 70 mm in polymethylmethacrylate (PMMA) were evaluated. Combining these values, an FOM was defined to determine the optimal combination. RESULTS: The results indicated that the Mo/Rh and W/Rh combinations present mean glandular doses below the limit for all thicknesses. In contrast, using the Mo/Mo combination, the mean glandular doses were below the limit only up to 45 mm. However, when considering the FOM that combines dosimetric aspects and the contrast-detail threshold, the use of W/Rh is the most optimal option. CONCLUSION: The results obtained in this study demonstrate that the W/Rh combination in direct digital mammography is the option that presents the best trade-off between the mean glandular dose and the contrast-detail detection threshold. IMPLICATIONS FOR PRACTICE: The results demonstrate that the application of the W/Rh combination in direct digital mammography offers an optimized and applicable option, regardless of the thickness of the breast that will be radiographed.

Lethal Effect and Behavioral Responses of Leaf-Cutting Ants to Essential Oil of Pogostemon cablin (Lamiaceae) and Its Nanoformulation.

Leaf-cutting ants belonging to the genus Atta (Formicidae: Myrmicinae) are important pests in agricultural and forest environments. In the present study, we evaluated the formicidal activity of the essential oil of Pogostemon cablin and its nanoformulation on the leaf-cutting ants: Atta opaciceps (Borgmeier, 1939), Atta sexdens (Linnaeus, 1758), and Atta sexdens rubropilosa Forel, 1908. The nanoformulation was developed by magnetic stirring using polyoxyethylene (36%), pure ethanol (36%), essential oil of P. cablin (18%), and water (10%). Bioassays of acute toxicity by fumigation and behavioral bioassays in treated arenas, with and without choice, were performed. The essential oil of P. cablin and its nanoformulation demonstrated efficient insecticidal activity and irritability to ant species. The concentration required to kill 50% of workers varied from 1.06 to 2.10 µL L-1, with a mean time to death of less than or equal to 42 h. The essential oil of P. cablin and its nanoformulation reduced the displacement and velocity speed of the workers of A. opaciceps and A. sexdens rubropilosa in totally treated arenas. In the bioassays with choices, the three species of ants walked less and at a greater speed on the treated side of arena. This work demonstrates the potential of the essential oil of P. cablin and its nanoformulation to the generation of new formicidal products.

Chitosan/pvp-based mucoadhesive membranes as a promising delivery system of betamethasone-17-valerate for aphthous stomatitis.

Mucoadhesive membranes were proposed in this study as drug delivery system for betamethasone-17-valerate (BMV) in the treatment of recurrent aphthous stomatitis (RAS). The membranes were obtained by using the polymers chitosan (CHI) in both presence and absence of polyvinilpyrrolidone (PVP), following the solvent evaporation method. The presence of PVP in the membranes causes significant modifications in its thermal properties. Changes in the thermal events at 114 and 193 °C (related to BMV melting point), and losses in mass (39.38 and 30.68% for CH:PVP and CH:PVP-B, respectively), suggests the incorporation of BMV in these membranes. However, the morphological aspects of the membranes do not change after adding PVP and BMV. PVP causes changes in swelling ratios (>80%) of the membranes, and it is suggested that the reorganization of the polymer mesh was highlighted by the chemical interactions between the polymers leading to different percentages of BMV released ∼40% and ∼80% from CH-B and CH:PVP-B. BMV release profile follows Korsmeyer and Peppas model (n > 0.89) which suggests that the diffusion of the drug in the swollen matrix is driven by polymer relaxation. In addition, the membranes containing PVP (higher swelling ability) present high rates of tensile strength, and therefore, higher mucoadhesion. Moreover, given the results presented, the developed mucoadhesive membranes are a promising system to deliver BMV for the treatment of RAS.

X-ray powder diffraction at the XRD1 beamline at LNLS.

Various upgrades have been completed at the XRD1 beamline at the Brazilian synchrotron light source (LNLS). The upgrades are comprehensive, with changes to both hardware and software, now allowing users of the beamline to conduct X-ray powder diffraction experiments with faster data acquisition times and improved quality. The main beamline parameters and the results obtained for different standards are presented, showing the beamline ability of performing high-quality experiments in transmission geometry. XRD1 operates in the 5.5-14 keV range and has a photon flux of 7.8 × 109 photons s-1 (with 100 mA) at 12 keV, which is one of the typical working energies. At 8 keV (the other typical working energy) the photon flux at the sample position is 3.4 × 1010 photons s-1 and the energy resolution ΔE/E = 3 × 10-4.

An environmentally safe larvicide against Aedes aegypti based on in situ gelling nanostructured surfactant systems containing an essential oil.

HYPOTHESIS: Liquid crystalline precursors, which are in situ gelling nanostructured surfactant systems, can undergo phase transition in aqueous solution and become more structured aggregates, controlling release of larvicides and acting as biotechnology alternatives for dengue control. Such systems can contain bioactive substances as Citrus sinensis essential oil (CSEO) which exhibits biological activity against Aedes aegypti (Ae. aegypti) larvae. EXPERIMENTS: The formulations were composed by fixed concentration of CSEO stabilized by Polyoxypropylene (5) Polyoxyethylene (20) Cetyl Ether (PPG-5 CETETH-20): oleic acid (OA) 2:1, increasing water content. The phase diagram was established and systems structure was evaluated by polarized light microscopy (PLM), small angle X-ray scattering (SAXS) and rheology. Median lethal concentration was determined against Ae. aegypti larvae. FINDINGS: The phase diagram exhibited four regions: liquid crystal (LC), emulsion, microemulsion (ME) and phase separation. The PLM and SAXS distinguished microemulsions, lamellar and hexagonal LC structures. Flow and oscillatory tests showed that increasing water content increases elasticity from Newtonian to non-newtonian behavior confirming the in situ gelation behavior. The larvicidal activity of formulations indicates that these nanostructured systems improved the oil solubility in aqueous medium and in addition are potential environmental larvicide against Ae. aegypti larvae.

Caracterização da produtividade do funcho (Foeniculum vulgare Mill. ) no sertão de Sergipe / Characterization of the of fennel's (Foeniculum vulgare Mill. ) yield semi-arid areas of Sergipe state

Com o objetivo de avaliar a produtividade e qualidade do funcho (Foeniculum vulgare Mill.) produzido nas condições edafoclimáticas de Sergipe, foi conduzido cultivo orgânico de funcho em Frei Paulo-SE. Em junho de 2008 e de 2009, início do período de chuvas, foram instalados plantios por meio de mudas. Adicionalmente, em dezembro de 2010 foi realizada colheita de frutos a partir de plantas obtidas após poda drástica e rebrota. Foi realizada colheita de frutos e determinação da produtividade de dezembro a janeiro de 2008, 2009 e em dezembro de 2010. Verificou-se produtividade de 720 Kg.ha-1, no primeiro plantio e de 349 Kg.ha-1 no plantio de 2009. As plantas obtidas por rebrota em 2010 resultaram em produtividade de 589 Kg.ha-1. Sugere-se que a maior produtividade verificada no primeiro ano seja decorrente da maior precipitação média e conseqüente maior disponibilidade de água. A produtividade verificada nas plantas que rebrotaram em 2010 foi também superior a verificada em 2009, o que pode ser explicado tanto em função da maior precipitação, quanto em função do provável maior desenvolvimento das raízes e maior número de ramos após poda, devido à quebra da dominância apical. Esses dados sugerem importância da disponibilidade hídrica na determinação da produtividade na região e explicam a variação na produtividade verificada. A massa seca dos frutos (5, 29 g para 1000 frutos) e o alto teor de óleo essencial verificado (3,2 por cento), assim como a composição do óleo, revelam a alta qualidade dos frutos produzidos na região.

Aiming to evaluate the productivity and quality of fennel fruits produced in the countryside of Sergipe, with no irrigation, they were evaluated organic crops in Frei Paulo-SE. They were installed crops in 2008 and 2009 from seeds, on beginning rainy time. Seedlings obtained from seeds were transplanted in June 2008 and 2009. Besides, after the last harvest of the plants, grown in 2009, it was done a drastic pruning on plants, on May, 2010. The plants were held on the area until their fruits harvest, on december and January of 2008, 2009 and December 2010. The fennel fruits yield was 720 Kg ha -1 in the first crop (2008) and 349 Kg ha -1 at following crop (2009), while the fruits yield obtained from pruned plants was 589 Kg.ha-1. It is suggested that the higher yield at the first year has been due to the higher average rainfall and its greater availability of water. The observed yield in sprouted plants was higher (at 2010) than fennel yield of 2009. It can be explained as a function of precipitation, likely as a function of greater root development and increased number of branches and umbels after pruning and breaking of apical. These results reveal water availability importance to fennel yield. The dried mass of fruits (5.29 g to 1000 fruits), high content of essential oil in fruits (3.2 percent) and the essential oil composition reveal good quality of fennel fruits of Sergipe.

Lymphocyte proliferation testing in chromium allergic contact dermatitis.

BACKGROUND: Lymphocyte proliferation testing (LPT) has some advantages over patch testing to diagnose allergic contact dermatitis. It is harmless, objective and can be used in clinical situations where patch testing is not recommended. Unfortunately, significant success has only been achieved with nickel. There are few studies on chromium LPT and they were performed with different methods, leading to inconsistent results. METHODS: To determine the best parameters for chromium LPT, we tested 20 patients with allergic contact dermatitis to the metal and 20 controls, using various protocols. RESULTS: The best sensitivity and specificity ratios were achieved with 6-day cultures stimulated with a range from 7.5 x 10(-4) to 5 x 10(-3) mol/L of nonfiltered chromium chloride solutions. The sensitivity, specificity and accuracy values found within this range were 65%, 95% and 80%, respectively. CONCLUSION: Further investigation is necessary to achieve better sensitivity values.

Effects of essential oils on Aedes aegypti larvae: alternatives to environmentally safe insecticides.

The essential oils from leaves of Hyptis fruticosa (Lamiaceae) Salzm., H. pectinata (Lamiaceae) Poit., and Lippia gracilis (Verbenaceae) HBK were investigated for their larvicidal activity against Aedes aegypti and analyzed by GC/MS. Fifty-nine compounds, representing 91.28-98.39% of the essential oils, have been identified. A standard solution was used to make 20 mL solutions ranging from 30 to 2000 ppm. Twenty larvae between third and fourth stages were added to the essential oil solution. A mortality count was conducted 24 h after treatment. Essential oils LC50 and their confidence limits at 95% probability were calculated by the methods of Reed-Muench and Pizzi, respectively. The essential oil of Lippia gracilis showed potent insecticidal effect against Aedes aegypti larvae, the vector of dengue fever. Carvacrol and caryophyllene oxide were the main responsible for the activity of L. gracilis and H. pectinata. Minor compounds are probably acting synergistically to achieve H. fruticosa activity.

Trichophyton rubrum isolated from aids and human immunodeficiency virus-infected patients in São Paulo, Brazil: antifungal susceptibility and extracellular enzyme production.

BACKGROUND: In order to identify intraspecific variations in Trichophyton rubrum and to correlate them to the immunological status of the host, sixty strains isolated from AIDS, HIV-positive and HIV-negative patients were compared for the production of extracellular enzymes and for their susceptibility to several antifungal drugs. METHODS: The isolates were tested for their ability to secrete keratinases, proteinases, phospholipases, lipases and DNases. Likewise, we investigated their susceptibility to amphotericin B, ketoconazole, ciclopiroxolamine, griseofulvin, miconazole and tolnaftate. RESULTS: Variations in the Minimal Inhibitory Concentration (MIC80)) values were observed for all antifungals tested, but they were similarly distributed among the three clinical groups. Griseofulvin showed the most prominent differences among the three groups of isolates. Regarding enzyme secretion, all samples secreted keratinases and DNases, while none secreted phospholipases. Proteinases and lipases were secreted by some of them. CONCLUSIONS: The differences among isolates of the three groups were not statistically significant and therefore could not be ascribed to a given clinical status. Intraspecific variations similarly occurred in each group, irrespective of the immunological status of the patients.

Onychomycosis caused by Scytalidium dimidiatum. Report of two cases. Review of the taxonomy of the synanamorph and anamorph forms of this coelomycete.

The authors report two cases of onychomycosis in the dystrophic form, one of them involving an HIV-positive patient, provoked by Scytalidium dimidiatum, previously called Scytalidium lignicola. The subject is reviewed from the taxonomic viewpoint, considering the anamorph Hendersonula toruloidea as a synonym of Nattrassia mangiferae, and having Scytalidium dimidiatum as the major synanamorph. According to many mycologists, Scytalidium hyalinum may be a separate species or a hyaline mutant of Scytalidium dimidiatum. Scytalidium lignicola Pesante 1957 was considered to be the type-species of the genus by ELLIS (1971)13 and later to be a "conidial state" of Hendersonula toruloidea by the same author, today known as Nattrassia mangiferae. The microorganism lives only on the roots of certain plants (mainly Platanus and Pinus). It produces pycnidia and is not considered to be a pathogen, although it is considered as a possible emerging agent capable of provoking opportunistic fungal lesions. The importance of this topic as one of the most outstanding in fungal taxonomy, so likely to be modified over time, as well as its interest in the field of dermatologic mycology, are emphasized.

Pig bite in Brazil: a case series from a teaching hospital.

A retrospective survey done from 1987 till 1990 revealed that 23 patients bitten by pigs sought medical help at a teaching hospital in Uberlândia, in southeastern Brazil. Most cases (21) were from Uberlândia. The cases were evenly distributed by month and by year; most of them (14/16; 87.5%) occurred between 7.00 a.m. and 7.00 p.m. The male to female ratio was 6.7:1. Age ranged from 6 to 73 (mean 38.95 +/- SD 22.06, median 36). The bites were more common on the upper limbs, particularly on the forearms. In 11 (47.8%) cases the injury was described as deep. In most cases where information was available the injury was related to capture, transport or immobilisation of the pig for slaughter. The following medical procedures were performed: local cleansing in 19(82.6%) cases, rabies vaccine (12; 52.2%), antirabies serum (2; 8.7%), suturing (6; 26.1%) and tetanus vaccine (12; 52.2%). There was no case of infection at the bite site, neither of rabies or tetanus. By our data, the annual incidence of pig bite in Uberlândia can be estimated to be about 1.5/100,000.

[Presence of Toxocara spp eggs in public squares of Uberlandia city, Minas Gerais, Brazil]. / Presença de ovos de Toxocara spp em praças públicas da cidade de Uberlandia, Minas Gerais, Brasil.

The objective of this study was to verify the presence of Toxocara spp eggs in the public squares ground in Uberlândia, region of Triângulo Mineiro, from October 1991 to January 1992. The city has 89 squares distributed in 39 boroughs. In order to have an outline of the parasite's occurrence, ground and sand (when existent) samples were collected from one square per boroughors. The squares were determined by draw. The homogenized ground samples of distinct points of the 39 squares, were collected in plastic flasks and analysed by the methods of fluctuation in sodium chloride saturated solution and magnesium sulphate saturated solution which contained 5% of potassium iodate. Both methods were executed twice for each sample. The results showed that the ground of 9 squares (23.07%) was contaminated, 6 of which were located near downtown. The execution of more than one laboratorial method permitted the agent's identification in a greater percentage of squares.