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showing 10 items of 1128 documents
Single cell transplantation reveals interspecific cell communication in Drosophila chimeras
1990
Abstract Cell –cell communication is not only a common strategy for cell fate specification in vertebrates, but plays important roles in invertebrate development as well. We report here on experiments testing the compatibility of mechanisms specifying cell fate among six different Drosophila species. Following interspecific transplantation, the development of single ectodermal cells was traced in order to test their abilities to proliferate and differentiate in a heterologous environment. Despite considerable differences in cell size and length of cell cycle among some of the species, the transplants gave rise to fully differentiated clones that were integrated into the host tissue. Clones …
High levels of exogenous C2-ceramide promote morphological and biochemical evidences of necrotic features in thyroid follicular cells
2002
CD95 and ceramide are known to be involved in the apoptotic mechanism. The triggering of CD95 induces a cascade of metabolic events that progressively and dramatically modifies the cell shape by intense membrane blebbing, leading to apoptotic bodies production. Although the CD95 pathway has been abundantly described in normal thyrocytes, the effects of cell permeable synthetic ceramide at morphological and biochemical levels are not fully known. In the present study, we show that thyroid follicular cells (TFC) exposed to 20 microM of C(2)-ceramide for 4 h are characterized by morphological features of necrosis, such as electron-lucent cytoplasm, mitochondrial swelling, and loss of plasma me…
Preclinical and clinical evidence of activity of pazopanib in solitary fibrous tumour
2014
Abstract Background To explore the activity of pazopanib in solitary fibrous tumour (SFT). Patients and methods In a preclinical study, we compared the activity of pazopanib, sorafenib, sunitinib, regorafenib, axitinib and bevacizumab in a dedifferentiated-SFT (DSFT) xenotransplanted into Severe Combined Immunodeficiency (SCID) mice. Antiangiogenics were administered at their reported optimal doses when mean tumour volume (TV) was 80 mm3. Drug activity was assessed as TV inhibition percentage (TVI%). From May 2012, six consecutive patients with advanced SFT received pazopanib, on a national name-based programme. In one case sunitinib was administered after pazopanib failure. Results In the …
Performance of Markers and the Homologous Series Method for Dead Time Estimation in Reversed-Phase Liquid Chromatography
2009
Abstract Two methods for dead time estimation (the use of markers and the homologous series mathematical method) are revised. Out of twelve assayed common markers, only KBr, KI, tartrazine, thiourea, uracil, and urea yielded retention times independent of the mobile phase composition in the range 10–90% acetonitrile, using a Zorbax Eclipse XDB−C18 column. On the other hand, the quality of the estimations provided by the homologous series method was limited by the mathematical approach and the data quality. With this method, the estimated dead time is an extrapolated value, which is severely affected by the data of the most retained compounds that act as leverage points, biasing the result. …
Fractal Dimension of Transdermal-Delivery Drug Models: 4-Alkylanilines
2008
Abstract The pathways that exist in porous membranes used to deliver drugs form fractal percolating paths. For a homologous series of 4-alkylanilines, the fractal dimension D is calculated as a model for transdermal-delivery drugs. Program TOPO is used for the calculation of the solvent-accessible surface AS, which is denoted by the centre of a probe, which is allowed to roll on the outside while maintaining contact with the bare molecular surface S. AS depends on the probe radius R. For 4-alkylanilines, the quadrupole moment Θ is doubled. The hydrophobic contribution to AS is doubled while its hydrophilic part remains constant. D increases 11%. Geometric descriptor and topological index re…
Quantitation of hydrophobicity in micellar liquid chromatography
1999
Abstract Micellar liquid chromatography (MLC) is shown to be a promising technique for measuring the hydrophobicity of solutes. The presence of micelles has a profound effect on the chromatographic characteristics of reversed-phase columns. The linear relationships between the logarithm, log k , of the retention factor and such diverse properties as the number of carbon atoms in homologous series, octanol–water partition coefficients and solvatochromic parameters, which are observed in conventional reversed-phase liquid chromatography (RPLC), are not usually valid in MLC. For series of compounds exhibiting a wide range of hydrophobicity, k itself is linearly related to these properties. The…
Kinetic study of the release of aroma compounds in different model food systems
2007
Abstract Kinetics of release as a function of time from different model food matrices (mineral water, an oil-in-water emulsion, a carbohydrate matrix and a complex matrix containing lipids and carbohydrates) were measured at 37 °C for four flavour compounds. Carbohydrate matrix and complex matrix were elaborated to have a similar rheological behaviour. Flavour compounds belonging to the strawberry flavour note were chosen: a homologous series of ethyl esters (C4, C6 and C8) and a ketone (C5). The influence of the nature of flavour compounds on the kinetics of release was studied. On the other hand, the influence of the composition of the matrix on the kinetics of release was pointed out. Fr…
Eight million years of maintained heterozygosity in chromosome homologs of cercopithecine monkeys
2020
In the Cercopithecini ancestor two chromosomes, homologous to human chromosomes 20 and 21, fused to form the Cercopithecini specific 20/21 association. In some individuals from the genus Cercopithecus, this association was shown to be polymorphic for the position of the centromere, suggesting centromere repositioning events. We set out to test this hypothesis by defining the evolutionary history of the 20/21 association in four Cercopithecini species from three different genera. The marker order of the various 20/21 associations was established using molecular cytogenetic techniques, including an array of more than 100 BACs. We discovered that five different forms of the 20/21 association w…
Two heterologously expressed Planobispora rosea proteins cooperatively induce Streptomyces lividans thiostrepton uptake and storage from the extracel…
2010
Abstract Background A bacterial artificial chromosomal library of Planobispora rosea, a genetically intractable actinomycete strain, was constructed using Escherichia coli-Streptomyces artificial chromosome (ESAC) and screened for the presence of genes known to be involved in the biosynthesis of antibiotics. Results One clone with a 40 kb insert showed antimicrobial activity against Gram positive bacteria. Insert sequence analysis and subcloning experiments revealed that the bioactivity was due to a 3.5 kb DNA fragment containing two open reading frames. These orfs encode two proteins with high similarity to a putative membrane protein of Streptomyces coelicolor and to the nogalamycin resis…