TcruziDB, an Integrated Database, and the WWW Information Server for the Trypanosoma cruzi Genome Project

Data analysis, presentation and distribution is of utmost importance to a genome project. A public domain software, ACeDB, has been chosen as the common basis for parasite genome databases, and a first release of TcruziDB, the Trypanosoma cruzi genome database, is available by ftp from ftp://iris.dbbm.fiocruz.br/pub/genomedb/TcruziDB as well as versions of the software for different operating systems (ftp://iris.dbbm.fiocruz.br/pub/unixsoft/). Moreover, data originated from the project are available from the WWW server at http://www.dbbm.fiocruz.br. It contains biological and parasitological data on CL Brener, its karyotype, all available T. cruzi sequences from Genbank, data on the EST-sequencing project and on available libraries, a T. cruzi codon table and a listing of activities and participating groups in the genome project, as well as meeting reports. T. cruzi discussion lists (tcruzi-l@iris.dbbm.fiocruz.br and tcgenics@iris.dbbm.fiocruz.br) are being maintained for communication and to promote collaboration in the genome project

Lipoxin agonists: turn right! to path of resolving neutrophil

An impressive array of cellular and molecular adaptive responses achieves homeostasis. The inflammatory reaction is an adaptive response triggered by an insult to culminate into the overt cardinal signs of inflammation, eventually leading to resolution and returning the organism back to its original centered state. This article focuses on some aspects of the lipoxin A4 signaling pathway during the resolution phase, to better understand molecular mechanisms by which a neutrophil directs an inflammatory reaction to switch off and resume homeostasis. Defining the resolution state of a neutrophil at the molecular level will aid in treatments of diseases that are associated with an exaggerated and uncontrolled inflammation.

The benefits of using selenium in the treatment of Chagas disease: prevention of right ventricle chamber dilatation and reversion of Trypanosoma cruzi-induced acute and chronic cardiomyopathy in mice

Cardiac damage is a frequent manifestation of Chagas disease, which is caused by the parasite Trypanosoma cruzi. Selenium (Se) is an essential micronutrient, the deficiency of which has been implicated in the development of cardiomyopathy. Our group has previously demonstrated that Se supplementation prevents myocardial damage during acute T. cruzi infection in mice. In this study, we analyzed the effect of Se treatment in cases of T. cruzi infection using prevention and reversion schemes. In the Se prevention scheme, mice were given Se supplements (2 ppm) starting two weeks prior to inoculation with T. cruzi(Brazil strain) and continuing until 120 days post-infection (dpi). In the Se reversion scheme, mice were treated with Se (4 ppm) for 100 days, starting at 160 dpi. Dilatation of the right ventricle was observed in the infected control group at both phases of T. cruzi infection, but it was not observed in the infected group that received Se treatment. Surviving infected mice that were submitted to the Se reversion scheme presented normal P wave values and reduced inflammation of the pericardium. These data indicate that Se treatment prevents right ventricular chamber increase and thus can be proposed as an adjuvant therapy for cardiac alterations already established by T. cruziinfection.

Assessment of intima-media complex in carotid, femoral and right subclavian arteries for early investigation of atherosclerosis in HIV-infected patients

Objective To compare automatic and manual measurements of intima-media complex (IMC) in common carotid, common femoral and right subclavian arteries of HIV-infected patients in relation to a control group, taking into consideration the classical risk factors for atherosclerosis. Materials and Methods The study sample comprised 70 HIV-infected patients and 70 non-HIV-infected controls paired according sex and age. Automatic (gold standard) and manual measurements of IMC were performed in the carotid arteries. Manual measurements were also performed in common femoral and right subclavian arteries. Bland-Altman graphs were utilized in the comparison and the adopted level significance was 5%. Results Intima-media complex alterations were not observed in any of the individuals as the mean automatic measurement in the right common carotid (RCC) artery was considered as the gold standard. As the gold standard was compared with the manual measurements (mean, maximum and minimum), no clinically significant alteration was observed. As the gold standard was compared with other sites, the difference was statistically and clinically significant at the origin of right subclavian artery (RCC: 0.51 mm vs. 0.91 mm) (p < 0.001). Conclusion HIV-infected individuals are not at higher risk for atherosclerosis than the control population.

Quimiometria I: calibração multivariada, um tutorial

The aim of this work is to present a tutorial on Multivariate Calibration, a tool which is nowadays necessary in basically most laboratories but very often misused. The basic concepts of preprocessing, principal component analysis (PCA), principal component regression (PCR) and partial least squares (PLS) are given. The two basic steps on any calibration procedure: model building and validation are fully discussed. The concepts of cross validation (to determine the number of factors to be used in the model), leverage and studentized residuals (to detect outliers) for the validation step are given. The whole calibration procedure is illustrated using spectra recorded for ternary mixtures of 2,4,6 trinitrophenolate, 2,4 dinitrophenolate and 2,5 dinitrophenolate followed by the concentration prediction of these three chemical species during a diffusion experiment through a hydrophobic liquid membrane. MATLAB software is used for numerical calculations. Most of the commands for the analysis are provided in order to allow a non-specialist to follow step by step the analysis.

O modelamento estatístico de misturas: experimento tutorial usando voltametria de redissolução anódica

This work illustrates the modeling procedure for a solvent mixture using the simplex- centroid approach. The selected experiment was the optimization of the peak current observed in the direct determination of nickel by anodic stripping voltammetry (ASV) in a solvent mixture composed of N,N-dimethylformamide, ethanol and water. The text is presented in a tutorial way, showing in detail the several steps which must be followed in such a process. Since not all possible mixtures lead to a measurable instrumental response, pseudocomponents had to be used to rescale the experimental design. This also allows to show how to apply this tool, usually troublesome for non-specialists in mixture modeling procedures.

Quimiometria II: planilhas eletrônicas para cálculos de planejamentos experimentais, um tutorial

This work describes, through examples, a simple way to carry out experimental design calculations applying an spreadsheets. The aim of this tutorial is to introduce an alternative to sophisticated commercial programs that normally are too complex in data input and output. An overview of the principal methods is also briefly presented. The spreadsheets are suitable to handle different types of computations such as screening procedures applying factorial design and the optimization procedure based on response surface methodology. Furthermore, the spreadsheets are sufficiently versatile to be adapted to specific experimental designs.

The stability of right- and left-handed alpha-helices as a function of monomer chirality

Poly-L-alanine forms stable right-handed alpha-helices, whereas Poly-D-alanine is stable as left-handed alpha helices.