Publications by authors named "Chinh T Bui"

Activating the intrinsic apoptosis pathway with small molecules is now a clinically validated approach to cancer therapy. In contrast, blocking apoptosis to prevent the death of healthy cells in disease settings has not been achieved. Caspases have been favored, but they act too late in apoptosis to provide long-term protection.

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Cinnoline and phenanthrene ring systems have been synthesized from a set of readily available substrates using functional group tolerant reactions. This approach proved successful in both solution- and solid-phase synthesis for phenanthrenes but was limited to solution-phase synthesis for cinnolines. The described approaches to these ring systems complements related approaches to other scaffolds that can be readily accessed from the same substrates using slight variations in the applied chemistry.

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A concise and efficient solid-phase synthesis of benzo[b]thiophenes and benzo[b]selenophenes based on a combination of palladium-mediated coupling and iodocyclization protocols has been developed.

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Solution-phase and solid-phase permanganate oxidation reactions of thymine acetic acid were investigated by spectroscopy. The spectral data showed the formation of a stable organomanganese intermediate, which was responsible for the rise in the absorbance at 420 nm. This result enables unambiguous interpretation of the absorbance change at 420 nm, as the intermediate permanganate ions could be isolated on the solid supports.

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The electrophoretic gel-based chemical cleavage of the mismatch method gives an incomplete view of the DNA conformational changes induced by a single base mismatch. This spectroscopic study investigates the permanganate oxidation reactions with matched and mismatched DNA under constant and variable temperature conditions. The results, which include the oxidation levels, reaction patterns with isosbestic points, color changes, thermal spectra, spectroscopy derivative, and gel separation and melting temperatures, provide a fundamental background for identification of oligonucleotides containing single base mismatches by chemical means.

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KMnO4 has been well known as a powerful chemical probe for numerous applications in biological fields, particularly for those used in conformational studies of DNA. The KMnO4 assay provides essential information for understanding biochemical processes and detecting aberrant DNA, which is associated with many genetic diseases. Elegant examples are sequencing techniques, foot-printing assays for transcriptional studies, an interference method for hormone receptor binding assays as well as DNA conformational studies of Z-DNA, Z-Z junctions, hairpins, curvatures, short nucleotide base repeats, binding of intercalators and groove binders, etc.

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BACKGROUND: The conventional solution-phase Chemical Cleavage of Mismatch (CCM) method is time-consuming, as the protocol requires purification of DNA after each reaction step. This paper describes a new version of CCM to overcome this problem by immobilizing DNA on silica solid supports. RESULTS: DNA test samples were loaded on to silica beads and the DNA bound to the solid supports underwent chemical modification reactions with KMnO4 (potassium permanganate) and hydroxylamine in 3M TEAC (tetraethylammonium chloride) solution.

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The last decade has witnessed many exciting scientific publications associated with site-selective reactions of small chemical molecules with imperfectly matched DNA. Typical examples are carbodiimide, hydroxylamine, potassium permanganate, osmium tetroxide, chemical tagging probes, biotinylated, chemiluminescent and fluorescent probes, and all of them selectively react with imperfectly matched DNA. More recently, some therapeutic agents including DNA intercalating drugs and groove binders have been found to promote the in vivo repair system to recognize and repair the mismatch more effectively.

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The permanganate oxidation of free nucleotide bases was successfully studied in aqueous solution of tetraethylammonium chloride using spectroscopic techniques. The reaction was highly selective toward thymine and uracil, less with cytosine, very little reaction on guanine, and no reaction on adenine.

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