Search results for "fluorescence"

Fluorescent benzofurazan-cholic acid conjugates for in vitro assessment of bile acid uptake and its modulation by drugs.

2009

One of the most common mechanisms of hepatotoxicity is drug-induced cholestasis. Hence, new approaches for screening the cholestatic potential of drug candidates are desirable. In this context, we describe herein the use of synthetic 4-nitrobenzo-2-oxa-1,3-diazole (NBD) fluorescent conjugates of cholic acid (ChA) at positions 3alpha, 3beta, 7alpha, and 7beta for in vitro assessment of bile acid uptake. All the conjugates show a strong absorption band between 400 and 550 nm and have a fluorescence quantum yield of approximately 0.45, with an emission maximum centered at approximately 530 nm. After their photophysical characterization, 3alpha-, 3beta-, 7alpha-, and 7beta-NBD-ChA were used to …

Unique pharmacology of KAR-2, a potential anti-cancer agent: absorption modelling and selective mitotic spindle targeting.

2008

Abstract Bis-indols are a large group of the anti-cancer agents, which effectively arrest the uncontrolled division of the cancerous cells. Their use in clinical chemotherapy is still limited because of: (i) the non-specific targeting of the mitotic cells; (ii) low bioavailability of the drugs. KAR-2 has been identified as a tubulin binding agent which displays significantly lower cytotoxicity but favourable anti-cancer potency than its mother molecule, vinblastine. The objective of this paper, on one hand, was to show that the human intestinal epithelial Caco-2 cells, used for pharmacokinetic studies display distinct sensitivity against KAR-2 and vinblastine due to their distinct targeting…

High-performance liquid chromatography with fluorimetric detection in biological tissues of the 4-bromomethyl-7-methoxycoumarin ester derivative of 5…

1985

10qter deletion: A new case

2008

Vertebrate telomeres consist of tandem repeats of the TTAGGG sequence that cap the ends of chromosomes, protecting them from degradation and fusion. Extensive evidence has shown that telomere shortening and erosion lead lo chromo¬some end-to-end fusions and genomic instability, causing mental retardation and/or malformation syndromes. So far, over 19,000 patients with mental retardation have been tested and reported of whom -2.5% appeared to have a subtelomeric rearrange¬ment [Ravnan et al., 2006; Ballif et al., 2007; Ledbetter and Martin, 2007]. Since the identification of sub¬microscopic subtelomeric rearrangements as a major cause of mental retardation [Flint et al., 1995], testing for s…

The first case of myoclonic epilepsy in a child with a de novo 22q11.2 microduplication

2011

Chromosome 22, particularly the q11.2 sub-band, has long been recognized as responsible for multiple congenital anomaly disorders. In particular, its susceptibility to subtle microdeletions or, more rarely, microduplications has been attributed to the presence of several low-copy repeats spanning the region as mediators of nonallelic homologous recombination that result in 22q11.2 rearrangements. While recent data suggest that the frequency of 22q11.2 microduplications could be approximately half of all deletions, now only 50 unrelated cases have been reported thus far. However, it is reasonable to suppose that microduplications of 22q11.2 may be largely undetected as a result of a less-dis…

Conformational Change in the Pheromone-binding Protein fromBombyx mori Induced by pH and by Interaction with Membranes

1999

The pheromone-binding protein (PBP) from Bombyx mori was expressed in Escherichia coli periplasm. It specifically bound radiolabeled bombykol, the natural pheromone for this species. It appeared as a single band both in native and SDS-polyacrylamide gel electrophoresis and was also homogeneous in most chromatographic systems. However, in ion-exchange chromatography, multiple forms sometimes appeared. Attempts to separate them revealed that they could be converted into one another. Analysis of the protein by circular dichroism and fluorescence spectroscopy demonstrated that its tertiary structure was sensitive to pH changes and that a dramatic conformational transition occurred between pH 6.…

Isolation and characterization of cold-shock domain protein genes, Oryzias latipes Y-box protein 2 ( OlaYP2 ) and Fugu rubripes Y-box protein 1 ( Fru…

2002

The Y-box protein (YP) family shares a nucleic acid binding domain, called cold-shock domain, that has been evolutionarily highly conserved from bacteria to human. The different YPs identified so far in vertebrates are thought to function as transcriptional activators, transcriptional repressors and/or translational repressors. Medakafish and pufferfish are very suitable vertebrate models for the study of developmental genetics and comparative genomics, respectively. Here we report the isolation of two teleost YP genes, medakafish Oryzias latipes (Ola)YP2 and Fugu rubripes (Fru)YP1, which are expressed in multiple tissues. Phylogenetic analysis demonstrated that OlaYP2 and FruYP1 belong to …

A new case of 2q duplication supports either a locus for orofacial clefting between markers D2S1897 and D2S2023 or a locus for cleft palate only on c…

2005

We report on a pure duplication of the proximal chromosome 2q in a 6.5-year-old boy with V-shaped midline cleft palate and bifid uvula, posteriorly located tongue, and micrognathia (Pierre Robin sequence), celiac disease, failure to thrive, and developmental delay. Cytogenetic and FISH analysis indicated a duplication of chromosome 2q13-q22. In general, pure proximal duplication or triplication of 2q is rare. The clinical features and chromosomal breakpoints of the 10 previously reported patients varied, and no common phenotype or proximal duplication/triplication 2q syndrome could be defined to date. However, based on four previous patients with different orofacial clefts and our case, a l…

Differential metabolic profiling of non-pure trisomy 21 human preimplantation embryos.

2012

Objective To investigate the metabolomic signature of trisomy 21 preimplantation human embryos by a noninvasive approach using mass spectrometry– (MS-) and nuclear magnetic resonance spectroscopy– (NMR-) based metabolic profiling platforms. Design A total of 171 spent media samples were collected from day 3 embryos and comparatively analyzed by MS analysis (chromosomally normal embryos, n=15; trisomy 21 embryos, n=15) and a matched control media group (without embryo, n=14) and by NMR spectroscopy (normal embryos, n=39; trisomy 21 embryos, n=35; monosomy 21 embryos, n=24) and a matched control media group (without embryo, n=29). Setting IVF clinic/preimplantation genetic diagnosis (PGD) uni…

Defective nuclear localization of Hsp70 is associated with dyserythropoiesis and GATA-1 cleavage in myelodysplastic syndromes.

2012

Abstract Normal human erythroid cell maturation requests the transcription factor GATA-1 and a transient activation of caspase-3, with GATA-1 being protected from caspase-3–mediated cleavage by interaction with the chaperone heat shock protein 70 (Hsp70) in the nucleus. Erythroid cell dysplasia observed in early myelodysplastic syndromes (MDS) involves impairment of differentiation and excess of apoptosis with a burst of caspase activation. Analysis of gene expression in MDS erythroblasts obtained by ex vivo cultures demonstrates the down-regulation of a set of GATA-1 transcriptional target genes, including GYPA that encodes glycophorin A (GPA), and the up-regulation of members of the HSP70…