Reproducible Data (reproducible + data)

Distribution by Scientific Domains

Selected Abstracts

Systematic comparison of surface coatings for protein microarrays

Birgit Guilleaume Dr.
Abstract To process large numbers of samples in parallel is one potential of protein microarrays for research and diagnostics. However, the application of protein arrays is currently hampered by the lack of comprehensive technological knowledge about the suitability of 2-D and 3-D slide surface coatings. We have performed a systematic study to analyze how both surface types perform in combination with different fluorescent dyes to generate significant and reproducible data. In total, we analyzed more than 100 slides containing 1152 spots each. Slides were probed against different monoclonal antibodies (mAbs) and recombinant fusion proteins. We found two surface coatings to be most suitable for protein and antibody (Ab) immobilization. These were further subjected to quantitative analyses by evaluating intraslide and slide-to-slide reproducibilities, and the linear range of target detection. In summary, we demonstrate that only suitable combinations of surface and fluorescent dyes allow the generation of highly reproducible data. [source]

Investigation of norflurazon pesticide photodegradation using plasma desorption time-of-flight mass spectrometry analysis

J.-P. Thomas
We have previously demonstrated that PD-TOFMS (plasma desorption time-of-flight mass spectrometry) analysis is a powerful technique for the in situ analysis of pesticides deposited or adsorbed on solid materials. With the aim of producing reproducible data on the modification of a pesticide under controlled photodegradation conditions, we have now undertaken a study where both the substrate and the pesticide are well characterized. This is the case for norflurazon deposited onto an aluminium substrate, in particular regarding the reproducibility of preparation of the samples and the change with time of their chemical composition. Degradation parameters have been derived from the variation in yield of ions representative of the molecule and of its breakdown products and, particularly, from the time required for 50% dissipation of their initial concentration (DT50). DT50 values ranging between 1 and 10,h have been found. An interpretation of the degradation process is proposed from the decay of other ions. As expected, the degradation is faster when the UV sunlight is unfiltered (a factor of 3.8 for the molecule, and around 5 for the breakdown products). Copyright 2008 John Wiley & Sons, Ltd. [source]

Metabolomic approaches reveal that phosphatidic and phosphatidyl glycerol phospholipids are major discriminatory non-polar metabolites in responses by Brachypodium distachyon to challenge by Magnaporthe grisea

J. William Allwood
Summary Metabolomic approaches were used to elucidate some key metabolite changes occurring during interactions of Magnaporthe grisea, the cause of rice blast disease , with an alternate host, Brachypodium distachyon. Fourier-transform infrared (FT-IR) spectroscopy provided a high-throughput metabolic fingerprint of M. grisea interacting with the B. distachyon accessions ABR1 (susceptible) and ABR5 (resistant). Principal component,discriminant function analysis (PC-DFA) allowed the differentiation between developing disease symptoms and host resistance. Alignment of projected ,test-set' on to ,training-set' data indicated that our experimental approach produced highly reproducible data. Examination of PC-DFA loading plots indicated that fatty acids were one chemical group that discriminated between responses by ABR1 and ABR5 to M. grisea. To identify these, non-polar extracts of M. grisea -challenged B. distachyon were directly infused into an electrospray ionization mass spectrometer (ESI-MS). PC-DFA indicated that M. grisea -challenged ABR1 and ABR5 were differentially clustered away from healthy material. Subtraction spectra and PC-DFA loadings plots revealed discriminatory analytes (m/z) between each interaction and seven metabolites were subsequently identified as phospholipids (PLs) by ESI-MS-MS. Phosphatidyl glycerol (PG) PLs were suppressed during both resistant and susceptible responses. By contrast, different phosphatidic acid PLs either increased or were reduced during resistance or during disease development. This suggests considerable and differential PL processing of membrane lipids during each interaction which may be associated with the elaboration/suppression of defence mechanisms or developing disease symptoms. [source]

Quantitative Analysis of Human Platelet Adhesions Under a Small-Scale Flow Device

Katsuko S. Furukawa
Abstract To realize real-time evaluation of human platelet adhesions onto material surfaces with small volumes of human platelet suspensions, we developed an apparatus consisting of a modified cone and plate-type viscometer, combined with an upright epi-fluorescence microscope. The apparatus allowed real-time evaluation of platelet,material interactions and the initial event of thrombus formation, using small platelet suspension volumes (7.5 L) under shear flow conditions. To study the dynamic behavior of platelet,material interaction, we chose five representative opaque and transparent materials: acrylate resin (AC), polytetrafluoroethylene (PTFE), polyvynylchrolide (PVC), glass, and a monolayer of human normal umbilical cord vein endothelial cells (EC) on glass under shear flow conditions. The values of adhesiveness of human platelets to the test materials in descending order were as follows: AC > PTFE > PVC > glass > human EC. Under this new small-scale flow system, we could obtain highly reproducible data, which were comparable with results from a previously developed large-scale flow system. Therefore, the newly developed cone and plate-type rheometer is a useful instrument for testing and screening materials, and allows precise quantitative evaluation of human platelet adhesion. [source]

A New HPLC-ELSD Method To Quantify Indican in Polygonum tinctorium L. and To Evaluate ,-Glucosidase Hydrolysis of Indican for Indigo Production

Luciana G. Angelini
A method to quantify the indigo precursor indican (indoxyl-,- d -glucoside) in Polygonum tinctoriumL. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native ,-glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond ,-glucosidase and Novarom G preparation, were compared with P. tinctorium native ,-glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond ,-glucosidase , Novarom G. [source]

Diagnosis of pemphigus by ELISA: a critical evaluation of two ELISAs for the detection of antibodies to the major pemphigus antigens, desmoglein 1 and 3

Experimental dermatology, Original article
Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are characterized by autoantibodies to the desmosomal glycoproteins desmoglein 3 (Dsg 3) and Dsg 1 (Dsg 1), respectively. In this study, two enzyme-linked immunosorbent assays (ELISA) which detect IgG autoantibodies to Dsg 1 and Dsg 3 have been evaluated. A total of 317 normal and disease controls, 82 patients with PV and 25 with PF were studied. The Dsg 3 ELISA was positive in all 34 patients with untreated PV and the Dsg 1 ELISA was positive in all 10 with untreated PF. When patients undergoing treatment were included, the sensitivities fell to 95% and 92%, respectively, but still compared favourably to the sensitivity of indirect immunofluorescence which was 79% in PV and 84% in PF. All PF sera were negative in the Dsg 3 ELISA and the specificity of both assays was 98% or greater. Large numbers of samples could be analysed simultaneously over a relatively short time period. The Dsg 1 and Dsg 3 ELISAs also provided objective, quantitative, reproducible data which allowed differentiation of PV from PF and in view of these advantages, they are likely to become a routine technique in diagnostic laboratories. [source]

Photography of the anterior eye segment according to Scheimpflug's principle: options and limitations , a review

Alfred Wegener PhD
Abstract Scheimpflug photography and densitometric image analysis are very precise techniques for light scattering measurement and biometry in the anterior segment of the eye. They provide reproducible data on the characteristics of the anterior eye segment in clinical and experimental studies and the set of data obtained allows discrimination of light scattering changes because of ageing, disease or toxic effects. The techniques can also be used to determine no-effect levels or maximally tolerable dosages of physical and chemical noxious factors. Several Scheimpflug cameras have been marketed, but the only cameras commercially available today are the Nidek EAS 1000 and the Oculus Pentacam. This review outlines the development of the technique and its introduction into ophthalmology. Furthermore, the application of the technique in clinical and experimental ophthalmology as well as in ocular toxicology are presented and discussed. [source]