CLINICAL STUDY of NATURAL INFECTION BY Trypanosoma cruzi IN DOGS RESIDING IN A RURAL AREA IN MATO GROSSO do SUL STATE, BRAZIL

This study was carried out to describe the clinical characteristics of natural infection caused by Trypanosoma cruzi in dogs that reside in a rural area of Mato Grosso do Sul State, Brazil. Conventional and nonconventional diagnostic methods were used for screening T. cruzi infection in 75 dogs that lived in the area. Cardiovascular tests and biochemical examination of sera were also performed in four confirmed positive dogs. The following techniques were employed: indirect immunofluorescence test (IFAT), enzyme-linked immunosorbent assay with T. cruzi epimastigote antigens (EAE-ELISA) and enzyme-linked immunosorbent assay with T. cruzi excreted-secreted trypomastigote antigens (TESA-ELISA) with antibodies detected in 45.33% (n = 34), 24.0% (n = 18) and 12.0% (n = 9) of the dogs, respectively. The current prevalence of the infection was confirmed as 10.7% (n = 8) by immunoblotting test with T. cruzi excreted-secreted antigens (TESA-blot). The test that showed the best concordance index (Kappa; 0.93), sensitivity (100%) and specificity (98.5%) was TESA-ELISA, that when associated with IFAT had the same results as those obtained by TESA-blot (10.7%). Three out of the four chagasic animals showed enlarged cardiac silhouette on X-ray and an increase of the P-wave duration and QRS complex in electrocardiogram. Two dogs presented conduction disturbances, right bundle branch block in one dog and first-degree atrioventricular block and sinus arrest in another. The ecodopplercardiography presented left-ventricular-wall thickness increased during diastole, decrease of the shortening fraction and inversion in the speed peaks of the E and A waves, indicating the presence of systolic and diastolic disorders. The four animals showed enzymatic activities of creatine kinase (221-404 U/L), MB fraction of creatine kinase (189-304 U/L), elevated total proteins (7.6-10.2 g/dL) and total globulins (4.6-7.7g/dL) and reduction of albumin/globulin ratio, which suggested a myocardial injury and continuous antigenic stimulus.

A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems

Leaf-cutting ants of the genera Acromyrmex and Atta are considered the principal polyphagous pests of the Neotropics. Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests of Atta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems. Likewise, the pest species can be used to detect environmental disturbance. As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs.

Numerical and experimental analysis of natural convection in a cavity with flush mounted heat sources on a side wall

This work considers a problem of interest in several technological applications such as the thermal control of electronic equipment. It is also important to study the heat transfer performance of these components under off-normal conditions, such as during failure of cooling fans. The effect of natural convection on the flow and heat transfer in a cavity with two flush mounted heat sources on the left vertical wall, simulating electronic components, is studied numerically and experimentally. The influence of the power distribution, spacing between the heat sources and cavity aspect ratio have been investigated. An analysis of the average Nusselt number of the two heat sources was performed to investigate the behavior of the heat transfer coefficients. The results obtained numerically and experimentally, after an error analysis, showed a good agreement.

The effects of Chlorella vulgaris in the protection of mice infected with Listeria monocytogenes. Role of natural killer cells

In this work we have demonstrated the effects of oral administration of Chlorella vulgaris (CV) on Natural Killer cells (NK) activity of mice infected with a sublethal dose of viable Listeria monocytogenes. The treatment with C. vulgaris produced a significant increase on NK cells activity in normal (non-infected) animals compared to the animals that received only vehicle (water) (p < 0.0001). Similarly, the infection alone produced a significant increase on NK cells activity, which was observed at 48 and 72 hours after the inoculation of L. monocytogenes. Moreover, when CV was administered in infected animals, there was an additional increase in NK cells activity which was significantly higher than that found in the infected groups (p < 0.0001) CV treatment (50 and 500mg/Kg) of mice infected with a dose of 3x105 bacteria/animal, which was lethal for all the non- treated controls, produced a dose-response protection which led to a 20% and 55% survival, respectively (p < 0.0001).

Quick preparative separation of natural naphthopyranones with antioxidant activity by high-speed counter-current chromatography

The natural naphthopyranones paepalantine (1), paepalantine-9O-β-D-glucopyranoside (2) and paepalantine-9-O-β-D-allopyranosyl-(1→6)-O-β-D-glucopyranoside (3) were separated in a preparative scale from the ethanolic extract of the capitula of Paepalanthus bromelioides by high-speed counter-current chromatography (HSCCC). The solvent system used was composed of water-ethanol-ethyl acetate-hexane (10:4:10:4, v/v/v/v). This technique led to the separation of the three different naphthopyranone glycosides in pure form in approximately 7 hours. Paepalantine showed a good antioxidant activity when assayed by the DPPH radical spectrophotometric assay.

Isolation of natural inhibitors of papain obtained from Carica papaya latex

Studies were carried out to natural papain inhibitor from papaya latex. Fresh latex from green fruits of Carica papaya was collected and immediately transported in ice bath to the lab, from which three fractions with inhibitor effect of esterase papain activity were isolated by latex dialysis, Sephadex G-25 gel filtration and ionic exchange chromatography in SP-Sephadex C-25. The isolated fractions, identified as inhibitors I and II, showed a negative reaction with ninhydrin; however, the fraction identified as P-III showed positive reaction with ninhydrin. Kinetics data showed non-competitive inhibition (inhibitor I) and uncompetitive (inhibitors II and P -III).

Influence of natural fruit juices in removing the smear layer from root surfaces - An in vitro study

Certain elements of a patient's diet may be associated with dentin hypersensitivity. The intent of this study was to evaluate the degree of removal of the smear layer from dentin surfaces by various fruit juices. A smear layer was created on extracted human teeth by manual scaling. The roots were reduced and distributed into 8 experimental groups. Distilled water was the negative control. The juices were applied by 2 methods: topical application and topical application with friction. Specimens were photomicrographed and graded according to an index of smear layer removal. With topical application, all but 2 of the tested substances resulted in significantly greater removal of the smear layer and opening of dentinal tubules than was the case with the negative control (p = 0.05); the exceptions were Gala apple and Italian grape juices, which were no different from the control. For the active application (with friction), most substances removed more smear layer than the control (p < 0.05); Gala apple, Italian grape and orange juices were similar to the control. For each of the tested substances, removal of the smear layer did not differ with the method of application (topical vs. friction; p > 0.05). It is concluded that natural fruit juices can remove the smear layer from dentin surfaces, and the efficacy of this removal varies with the type of juice. © J Can Dent Assoc 2004.

Role of natural killer cells in antitumor resistance

Natural killer cells constitute a population of lymphocytes able to non-specifically destroy virus-infected and some kinds of tumor cells. Since this lytic activity was shown by non-immunized animals the phenomenon is denominated natural killer (NK) activity and contrasts with specific cytotoxicity performed by cytolytic T lymphocytes (CTLs) because it does not depends on MHC-restricted peptides recognition. In fact, the main feature of most functional receptors of NK cells (NKRs) is their ability to be inhibited by different kinds of class I MHC antigens. In the middle of the 1950's, Burnet & Thomas forged the concept of tumor immunosurveillance and NK cells can be considered one of the main figures in this phenomenon both for effector and regulatory functions. In the present review the early studies on the biology of NK cells were revisited and both their antitumor activity and dependence on the activation by cytokines are discussed.

Comparative study of disk diffusion and microdilution methods for evaluation of antifungal activity of natural compounds against medical yeasts Candida spp and Cryptococcus sp

Antifungal activity of natural products has been tested by adapting methods designed for synthetic drugs. In this study, two methods for the determination of antifungal activity of natural products, agar diffusion and broth microdilution, the CLSI reference methods for synthetic drugs, are compared and discussed. The microdilution method was more sensitive. The minimal inhibitory concentrations (MIC) of crude extracts, fractions and pure substances from different species of the plant families Piperaceae, Rubiaceae, Clusiaceae, Fabaceae and Lauraceae, from the Biota project, were determined. Antifungal activities against Candida albicans, C.krusei, C.parapsilosis and Cryptococcus neoformans were produced by several samples.

In vitro evaluation of the effect of natural orange juices on dentin morphology

The patient's diet has been considered an important etiological factor of dentin hypersensitivity. The frequent ingestion of acidic substances can promote the loss of dental structure or remove the smear layer. The purpose of this study was to evaluate the degree of smear layer removal and dentinal tubules exposure by different natural orange juices. Extracted human teeth were submitted to manual scaling in order to develop the smear layer. Seventy dentin samples were obtained and distributed into the following groups: Control, lime orange, lime, valência orange, navel orange, mandarin, and tangerine. Each group included 2 methods of application: Topical and topical + friction. After preparation for SEM analysis, photomicrographs were assessed by a blind calibrated examiner using an index system. The Kruskal-Wallis test indicated a significant influence of the orange juices on smear layer removal. Significant difference was observed between navel orange, valência orange, mandarin and the control group (p < 0.05). These orange juices resulted in greater removal of the smear layer and greater opening of dentinal tubules. The comparison between the application methods for each group using the Mann-Whitney test showed that friction increased smear layer removal significantly only for lime orange and lime. The data suggest that certain natural orange juices are more effective in terms of smear layer removal and dentinal tubules exposure than others.

The in vitro antimicrobial activity of natural infant fluoride-free toothpastes on oral micro-organisms

Purpose: The objective of this study was to evaluate the antimicrobial activity of six toothpastes for infants: 3 fluoride-free experimental toothpastes - cashew-based, mango-based and without plant extract and fluoride compared with 2 commercially fluoride-free toothpastes and 1 fluoridated toothpastes. Methods: Six toothpastes for infants were evaluated in this study: (1) experimental cashew-based toothpaste; (2) experimental mango-based toothpaste; (3) experimental toothpaste without plant extract and fluoride (negative control); (4) First Teeth brand toothpaste; (5) Weleda brand toothpaste; and (6) Tandy brand toothpaste (positive control). The antimicrobial activity was recorded against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus acidophilus, and Candida albicans using the agar plate diffusion test. Results: First Teeth, Weleda, mango-based toothpaste, and toothpaste without plant extract presented no antimicrobial effect against any of the tested micro-organisms. Cashew toothpaste had antimicrobial activity against S mutans, S sobrinus, and L acidophilus, but it showed no antimicrobial activity against C albicans. There was no statistical difference between the inhibition halo of cashew and Tandy toothpastes against S mutans and L acidophilus. Conclusions: Cashew fluoride-free toothpaste had inhibitory activity against Streptococcus mutans and Lactobacillus acidophilus, and these results were similar to those obtained for fluoridated toothpaste.

Influence of natural weathering on colour stability of materials used for facial prosthesis

Colour stability of resin and silicone is an important factor for longevity of facial prostheses. The aim of this study was to evaluate the colour stability of resins and silicone for facial prostheses. Three brands of acrylic resin and one of facial silicone were evaluated considering pigment incorporation for the colourless materials. Ten samples of each material were fabricated and submitted to measurements of chromatic alteration initially and after 90 and 180 days of weathering natural through visual analysis and spectrophotometry. Data were evaluated by ANOVA and Tukey test (p < 0.05). Statistically significant colour alteration was observed among some materials regardless of the period. The materials did not present a statistical difference between 90 and 180 days except for the pigmented heat-polymerized resin. The colour difference between pigmented Silastic MDX4-4210 and colourless Silastic was statistically significant (p < 0.01) in both periods as well as between pigmented and colourless heat-polymerized resin, and between the resins Rapidaflex and Lentaflex. The visual method demonstrated colour alteration in all materials evaluated during the first 90 days of ageing. All materials exhibited colour alteration due to exposure to environment. © 2012 Informa UK, Ltd.

Antioxidant activity of ginger extract (zingiber officinale) in soybean oil under thermoxidation

Purpose: The purpose of this paper is to evaluate the antioxidant activity of ginger ethanol extract in soybean oil under thermoxidation. Design/methodology/approach: A total of four treatments were used: soybean oil free of synthetic antioxidants, soybean oil containing 2,500 mg/kg of ginger extract, soybean oil containing 50 mg/kg of TBHQ, soybean oil containing the mixture of natural extract, and TBHQ in the before-cited concentration. The treatments were discontinuously submitted to plates heated at 180°C, for 20 hours. Samples were removed in the times of 0, 4, 8, 12, 16 and 20 hours of heating and they were analyzed as to their oxidative stability, total polar compounds, peroxide and conjugated diene values. Findings: The results showed the efficiency of the ginger extract in protecting the oil against lipid oxidation. It could be concluded that ginger extract might be indicated as an additive that acts against lipid oxidation and, consequently, increases shelf life of food. Practical implications: These studies may prove to be beneficial to the exploitation of natural antioxidant sources for the preservation and/or extension of raw and processed food shelf life. Therefore, they could also be applied in the area of pharmaceuticals for the protection of human life. Originality/value: This study offers information on the use of natural antioxidants as an alternative to the use of synthetic antioxidants, which might be considered toxic. © Emerald Group Publishing Limited.

Thermal, rheological, and structural behaviors of natural and modified cassava starch granules, with sodium hypochlorite solutions

The use of chemically modified starches is widely accepted in various industries, with several applications. In this research, natural cassava starch granules were treated with standard sodium hypochlorite solution at 0.8, 2.0, and 5.0 g Cl/100 g starch. The native and modified starch samples were investigated by means of the following techniques: simultaneous thermogravimetry-differential thermal analysis, which allowed us to verify the thermal decomposition associated with endothermic or exothermic phenomena; and differential scanning calorimetry that was used to determine gelatinization enthalpy as well as the rapid viscoamylographic analysis that provided the pasting temperature and viscosity. By means of non-contact-atomic force microscopy method and X-ray powder patterns diffractometry, it was possible to observe the surface morphology, topography of starch granules, and alterations in the granules' crystallinity. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Influence of natural polymer derived from starch as a sensory modifier in sunscreen formulations

Background: Nowadays, there has been increased incidence of skin cancer, which is mainly related to increased sun exposure. Although sunscreen products may prevent the appearing of this disease, consumers may not use them due to some factors, including the sensory properties. The Aluminum Starch Octenylsuccinate (Dry-Flo® Pure, Akzo Nobel), an aluminum salt produced by the reaction of anhydride octenylsuccinic with starch, is able to improve the spreadability on the skin and reduce the oiliness of the formulation. Objective: To verify volunteers' acceptance for sunscreen formulation with natural polymer, compared with a control formulation (without polymer). Methods: To carry out the sensory analysis a formulation with or without 2. 0% Aluminum Starch Octenylsuccinate was prepared. Formulations had FPS 15, with critical wavelength of 353 nm, determined by testing in silico using the BASF® Sunscreen Simulator. Sensory analysis was performed on 60 students of both sexes, aged between 18 and 25 years, regular users of sunscreen products. Results: The results suggested that the polymer was able to promote a very soft and velvety feel on the skin when used in a sunscreen formulation, and it was able to mitigate and noticeably reduce the oiliness of the skin. Of the 60 volunteers who participated in the study, 45 volunteers (75%) considered that the polymer formulation provides little brightness or did not notice the difference in brightness of the skin after application. Conclusions: It was able to improve the sensory of the product, contributing to greater volunteers' acceptance.