Evaluation of plaque composition by intravascular ultrasound ""virtual histology"": the impact of dense calcium on the measurement of necrotic tissue

Aims: We aimed to evaluate if the co-localisation of calcium and necrosis in intravascular ultrasound virtual histology (IVUS-VH) is due to artefact, and whether this effect can be mathematically estimated. Methods and results: We hypothesised that, in case calcium induces an artefactual coding of necrosis, any addition in calcium content would generate an artificial increment in the necrotic tissue. Stent struts were used to simulate the ""added calcium"". The change in the amount and in the spatial localisation of necrotic tissue was evaluated before and after stenting (n=17 coronary lesions) by means of a especially developed imaging software. The area of ""calcium"" increased from a median of 0.04 mm(2) at baseline to 0.76 mm(2) after stenting (p<0.01). In parallel the median necrotic content increased from 0.19 mm(2) to 0.59 mm(2) (p<0.01). The ""added"" calcium strongly predicted a proportional increase in necrosis-coded tissue in the areas surrounding the calcium-like spots (model R(2)=0.70; p<0.001). Conclusions: Artificial addition of calcium-like elements to the atherosclerotic plaque led to an increase in necrotic tissue in virtual histology that is probably artefactual. The overestimation of necrotic tissue by calcium strictly followed a linear pattern, indicating that it may be amenable to mathematical correction.

Evaluation of GFP Tag as a Screening Reporter in Directed Evolution of a Hyperthermophilic beta-Glucosidase

By applying a directed evolution methodology specific enzymatic characteristics can be enhanced, but to select mutants of interest from a large mutant bank, this approach requires high throughput screening and facile selection. To facilitate such primary screening of enhanced clones, an expression system was tested that uses a green fluorescent protein (GFP) tag from Aequorea victoria linked to the enzyme of interest. As GFP`s fluorescence is readily measured, and as there is a 1:1 molar correlation between the target protein and GFP, the concept proposed was to determine whether GFP could facilitate primary screening of error-prone PCR (EPP) clones. For this purpose a thermostable beta-glucosidase (BglA) from Fervidobacterium sp. was used as a model enzyme. A vector expressing the chimeric protein BglA-GFP-6XHis was constructed and the fusion protein purified and characterized. When compared to the native proteins, the components of the fusion displayed modified characteristics, such as enhanced GFP thermostability and a higher BglA optimum temperature. Clones carrying mutant BglA proteins obtained by EPP, were screened based on the BglA/GFP activity ratio. Purified tagged enzymes from selected clones resulted in modified substrate specificity.

Parameterization and Evaluation of Predictions of DSSAT/CANEGRO for Brazilian Sugarcane

The DSSAT/CANEGRO model was parameterized and its predictions evaluated using data from five sugarcane (Sacchetrum spp.) experiments conducted in southern Brazil. The data used are from two of the most important Brazilian cultivars. Some parameters whose values were either directly measured or considered to be well known were not adjusted. Ten of the 20 parameters were optimized using a Generalized Likelihood Uncertainty Estimation (GLUE) algorithm using the leave-one-out cross-validation technique. Model predictions were evaluated using measured data of leaf area index (LA!), stalk and aerial dry mass, sucrose content, and soil water content, using bias, root mean squared error (RMSE), modeling efficiency (Eff), correlation coefficient, and agreement index. The Decision Support System for Agrotechnology Transfer (DSSAT)/CANEGRO model simulated the sugarcane crop in southern Brazil well, using the parameterization reported here. The soil water content predictions were better for rainfed (mean RMSE = 0.122mm) than for irrigated treatment (mean RMSE = 0.214mm). Predictions were best for aerial dry mass (Eff = 0.850), followed by stalk dry mass (Eff = 0.765) and then sucrose mass (Eff = 0.170). Number of green leaves showed the worst fit (Eff = -2.300). The cross-validation technique permits using multiple datasets that would have limited use if used independently because of the heterogeneity of measures and measurement strategies.

Brazilian flavonoid database: Application of quality evaluation system

Much information on flavonoid content of Brazilian foods has already been obtained; however, this information is spread in scientific publications and non-published data. The objectives of this work were to compile and evaluate the quality of national flavonoid data according to the United States Department of Agriculture`s Data Quality Evaluation System (USDA-DQES) with few modifications, for future dissemination in the TBCA-USP (Brazilian Food Composition Database). For the compilation, the most abundant compounds in the flavonoid subclasses were considered (flavonols, flavones, isoflavones, flavanones, flavan-3-ols, and anthocyanidins) and the analysis of the compounds by HPLC was adopted as criteria for data inclusion. The evaluation system considers five categories, and the maximum score assigned to each category is 20. For each data, a confidence code (CC) was attributed (A, B, C and D), indicating the quality and reliability of the information. Flavonoid data (773) present in 197 Brazilian foods were evaluated. The CC ""C"" (as average) was attributed to 99% of the data and ""B"" (above average) to 1%. The main categories assigned low average scores were: number of samples; sampling plan and analytical quality control (average scores 2, 5 and 4, respectively). The analytical method category received an average score of 9. The category assigned the highest score was the sample handling (20 average). These results show that researchers need to be conscious about the importance of the number and plan of evaluated samples and the complete description and documentation of all the processes of methodology execution and analytical quality control. (C) 2010 Elsevier Inc. All rights reserved.

Evaluation of protective effects of fish oil against oxidative damage in rats exposed to methylmercury

The present study evaluates a possible protective effect of fish oil against oxidative damage promoted by methylmercury (MeHg) in sub-chronically exposed rats. Reduced glutathione peroxidase and catalase enzyme activity and reduced glutathione levels were observed in MeHg-exposed animals compared to controls. Methylmercury exposure was also associated with DNA damage. Administration of fish oil to the methylmercury-exposed animals did not ameliorate enzyme activity or glutathione levels. On the other hand, a significant DNA protective effect (about 30%) was observed with fish oil treatment. There were no differences in the total mercury concentration in rat liver, kidney, heart or brain after MeHg administration with or without fish oil co-administration. Histopathological analyses showed a significant leukocyte infiltration in rat tissues after MeHg exposure, but this effect was significantly reduced after co-administration of fish oil. Taken together, our findings demonstrate oxidative damage even after low-level MeHg exposure and the protective effect of fish oil. This protection seems not to be related to antioxidant defenses or mercury re-distribution in rat tissues. It is probably due to the anti-inflammatory effects of fish oil. (C) 2010 Elsevier Inc. All rights reserved.

Excised Porcine Cornea Integrity Evaluation in an in vitro Model of Iontophoretic Ocular Research

Background/Aims: It is a challenge to adapt traditional in vitro diffusion experiments to ocular tissue. Thus, the aim of this work was to present experimental evidence on the integrity of the porcine cornea, barrier function and maintenance of electrical properties for 6 h of experiment when the tissue is mounted on an inexpensive and easy-to-use in vitro model for ocular iontophoresis. Methods: A modified Franz diffusion cell containing two ports for the insertion of the electrodes and a receiving compartment that does not need gassing with carbogen was used in the studies. Corneal electron transmission microscopy images were obtained, and diffusion experiments with fluorescent markers were performed to examine the integrity of the barrier function. The preservation of the negatively charged corneal epithelium was verified by the determination of the electro-osmotic flow of a hydrophilic and non-ionized molecule. Results: The diffusion cell was able to maintain the temperature, homogenization, porcine epithelial corneal structure integrity, barrier function and electrical characteristics throughout the 6 h of permeation experiment, without requiring CO(2) gassing when the receiving chamber was filled with 25 m M of HEPES buffer solution. Conclusion: The system described here is inexpensive, easy to handle and reliable as an in vitro model for iontophoretic ocular delivery studies. Copyright (C) 2010 S. Karger AG, Basel

Evaluation of the Binding Properties of Maghemite Nanoparticle Surface-Coated with Meso-2-3-Dimercaptosuccinic Acid to Serum Albumin

In this study the interaction between magnetic nanoparticles (MNPs) surface-coated with meso-2,3-dimercaptosuccinic acid (DMSA) with both bovine serum albumin (BSA) and human serum albumin (HSA) was investigated. The binding of the MNP-DMSA was probed by the fluorescence quenching of the BSA and HSA tryptophan residue. Magnetic resonance and light microscopy analyses were carried out in in vivo tests using female Swiss mice. The binding constants (K(b)) and the complex stoichiometries (n) indicate that MNP-DMSA/BSA and MNP-DMSA/HSA complexes have low association profiles. After five minutes following intravenous injection of MNP-DMSA into mice`s blood stream we found the lung firstly target by the MNP-DMSA, followed by the liver in a latter stage. This finding suggests that the nanoparticle`s DMSA-coating process probably hides the thiol group, through which albumin usually binds. This indicates that biocompatible MNP-DMSA is a very promising material system to be used as a drug delivery system (DDS), primarily for lung cancer treatment.

DOUBLE ANEUPLOIDY (48,XXY,+21) OF MATERNAL ORIGIN IN A CHILD BORN TO A 13-YEAR-OLD MOTHER: EVALUATION OF THE MATERNAL FOLATE METABOLISM

Double aneuploidy, (48,XXY,+21) of maternal origin in a child born to a 13-year-old mother: evoluation of the maternal folate metabolism: The occurrence of non-mosaic double trisomy is exceptional in newborns. In this paper, a 48,XXY,+21 child, the parental origin of the extra chromosomes and the evaluation of the maternal folate metabolism are presented. The infant was born to a 13-year-old mother and presented with the typical clinical features of Down syndrome (DS). The origin of the additional chromosomes was maternal and most likely resulted from errors during the first meiotic division. Molecular analysis of 12 genetic polymorphisms involved in the folate metabolism revealed that the mother is heterozygous for the MTHFR C677T and TC2 A67G polymorphisms, and homozygous for the mutant MTRR A66G polymorphism. The maternal homocysteine concentration was 4.7 mu mol/L, a value close to the one considered as a risk factor for DS in our previous study. Plasma methylmalonic acid and serum folate concentrations were 0.17 mu mol/L and 18.4 ng/mL, respectively. It is possible that the presence of allelic variants for the folate metabolism and Hey concentration might have favored errors in chromosomal disjunction (hiring gametogenesis in this young mother. To our knowledge, this is the first patient with non-mosaic Down-Klinefelter born to a teenage mother, resulting from a rare fertilization event combining an abnormal 25,XX,+21 oocyte and a 23,Y spermatozoon.

Biological monitoring of a xenomaterial for grafting: an evaluation in critical-size calvarial defects

Our purpose was to evaluate the osteoconduction potential of mixed bovine bone (MBB) xenografts as an alternative for bone grafting of critical-size defects in the calvaria of rats. After surgery, in the time intervals of 1, 3, 6, and 9 months, rats were killed and their skulls collected, radiographed and histologically prepared for analysis. The data obtained from histological analysis reported that the particles of MBB did not promote an intense immunological response, evidencing its biocompatibility in rats. Our results clearly showed the interesting evidence that MBB was not completely reabsorbed at 9 months while a small amount of newly formed bone was deposited by osteoprogenitor cells bordering the defect. However, this discrete bone-forming stimulation was unable to regenerate the bone defect. Overall, our results suggest that the properties of MBB are not suitable for stimulating intense bone regeneration in critical bone defects in rats.

A Randomized Clinical Evaluation of a One- and Two-step Self-etch Adhesive Over 24 Months

Objective: To evaluate the performance of All Bond SE used in a one- or two-step protocol in a 24-month randomized clinical study. Methods: Thirty-three patients with two similarly sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the one-step All Bond SE protocol (SE-1) and the other half using the two-step All Bond SE protocol (SE-2). The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria and analyzed by the McNemar`s test and Fisher`s exact test (alpha=0.05). Results: After 24 months, six SE-1 and four SE-2 restorations were rated as Bravo in marginal discoloration The retention rates for SE-1 and SE-2 were 84.8% and 90.9%, respectively, after 24 months. Compared to baseline, the retention rate for SE-1 was statistically lower. Conclusions: All Bond SE used in the one- or two-step protocol resulted in high retention rates after 24 months.

Evaluation of IMRT and VMAT techniques with and without flattening filter using pareto optimal fronts

Mestrado em Radiações Aplicadas às Tecnologias da Saúde.

Quality of scientific articles

The paper discusses the difficulties in judging the quality of scientific manuscripts and describes some common pitfalls that should be avoided when preparing a paper for submission to a peer-reviewed journal. Peer review is an imperfect system, with less than optimal reliability and uncertain validity. However, as it is likely that it will remain as the principal process of screening papers for publication, authors should avoid some common mistakes when preparing a report based on empirical findings of human research. Among these are: excessively long abstracts, extensive use of abbreviations, failure to report results of parsimonious data analyses, and misinterpretation of statistical associations identified in observational studies as causal. Another common problem in many manuscripts is their excessive length, which makes them more difficult to be evaluated or read by the intended readers, if published. The evaluation of papers after their publication with a view towards their inclusion in a systematic review is also discussed. The limitations of the impact factor as a criterion to judge the quality of a paper are reviewed.

Evaluation of 99mTc-Sestamibi as a potential tool to investigate PgP activity in inflammation

Introduction: In the XXI Century ’s Society the scientific investigation process has been growing steadily , and the field of the pharmaceutical research is one of the most enthusiastic and relevant . Here, it is very important to correlate observed functional alterations with possibly modified drug bio distribution patterns . Cancer, inflammation and inf ection are processes that induce many molecular intermediates like cytokines, chemokines and other chemical complexes that can alter the pharmacokinetics of many drugs. One cause of such changes is thought to be the modulator action of these complexes in t he P - Glyco p rotein activity, because they can act like inducers/inhibitors of MDR - 1 expression. This protein results from the expression of MDR - 1 gene, and acts as an ATP energy - dependent efflux pump, with their substrates including many drugs , like antiretrovirals, anticancers, anti - infectives, immunosuppressants, steroids or opioids . Objectives: Because of the lack of methods to provide helpful information in the investigation of in vivo molecular changes in Pgp activity during infection/infl ammation processes, and its value in the explanation of the altered drug pharmacokinetic, this paper want to evaluate the potential utility of 99m Tc - Sestamibi scintigraphy during this kind of health sciences investigation. Although the a im is indeed to create a technique to the in vivo study of Pgp activity, this preliminary Project only reaches the in vitro study phase, assumed as the first step in a n evaluation period for a new tool development. Materials and Methods: For that reason , we are performing in vitro studies of influx and efflux of 99m Tc - Sestamibi ( that is a substrate of Pgp) in hepatocytes cell line (HepG2). We are interested in clarify the cellular behavior of this radiopharmaceutical in Lipopolysaccharide(LPS) stimulated cells ( well known in vitro model of inflammation) to possibly approve this methodology. To validate the results, the Pgp expression will be finally evaluated using Western Blot technique. Results: Up to this moment , we still don’t have the final results, but we have already enough data to let us believe that LPS stimulation induce a downregulation of MDR - 1, and consequently Pgp, which could conduce to a prolonged retention of 99m Tc - Sestamibi in the inflamed cells . Conclusions: If and when this methodology demonstrate the promising results we expect, one will be able to con clude that Nuclear Medicine is an important tool to help evidence based research also on this specific field .

Challenges and perspectives of academic evaluation

Academic evaluation has been an essential component of modern science since its inception, as science has moved away from personalized patronage toward its contemporary role as an essential enterprise of contemporary, democratic societies. In recent years, Brazil has experienced sustained growth in its scientific output, which is nowadays fully compatible with its status as a high middle-income country striving to become a fully developed, more equitable country in the years to come. Growth usually takes place amidst challenges and dilemmas and, in Brazil as elsewhere, academic evaluation is not exempt from such difficulties. In a large, profoundly heterogeneous country with a national evaluation system and nationwide on-line platforms disseminating information on the most disparate fields of knowledge, the main challenges refer to how to pay attention to detail without losing sight of comprehensiveness and how to handle social and regional diversity while preserving academic excellence as the fundamental benchmark.

Design, synthesis and biologival evaluation of novel isoniazid derivatives with potente antitubercular activity

The disturbing emergence of multidrug-resistant strains of Mycobacterium tuberculosis (Mtb) has been driving the scientific community to urgently search for new and efficient antitubercular drugs. Despite the various drugs currently under evaluation, isoniazid is still the key and most effective component in all multi-therapeutic regimens recommended by the WHO. This paper describes the QSAR-oriented design, synthesis and in vitro antitubercular activity of several potent isoniazid derivatives (isonicotinoyl hydrazones and isonicotinoyl hydrazides) against H37Rv and two resistant Mtb strains. QSAR studies entailed RFs and ASNNs classification models, as well as MLR models. Strict validation procedures were used to guarantee the models' robustness and predictive ability. Lipophilicity was shown not to be relevant to explain the activity of these derivatives, whereas shorter N-N distances and lengthy substituents lead to more active compounds. Compounds I, 2, 4, 5 and 6, showed measured activities against H37Rv higher than INH (i.e., MIC <= 0.28 mu M), while compound 9 exhibited a six fold decrease in MIC against the katG (S315T) mutated strain, by comparison with INH (Le., 6.9 vs. 43.8 mu M). All compounds were ineffective against H37Rv(INH) (Delta katG), a strain with a full deletion of the katG gene, thus corroborating the importance of KatG in the activation of INH-based compounds. The most potent compounds were also shown not to be cytotoxic up to a concentration 500 times higher than MIC. (C) 2014 Elsevier Masson SAS. All rights reserved.