Psoralen photophysics has been studied on quantum chemistry grounds using the multiconfigurational second-order perturbation method CASPT2. Absorption and emission spectra of the system have been rationalized by computing the energies and properties of the low-lying singlet and triplet excited states. The S1 pipi* state has been determined to be responsible of the lowest absorption and fluoresc...

Specific recognition of a region of duplex DNA by triplex-forming oligonucleotides (TFOs) provides an attractive strategy for genetic manipulation. Based on this, we have investigated the ability of the triplex-directed approach to induce mutations at a chromosomal locus in living cells. A mouse fibroblast cell line was constructed containing multiple chromosomal copies of the lambdasupFG1 vect...

The activation of 8-methoxypsoralen (8-MOP) by long-wavelength ultraviolet A light (UVA, 320-400 nm) induces the formation of interstrand cross-links in DNA. Psoralen plus UVA (PUVA) is widely used in the treatment of psoriasis, a hyperproliferative disease of the skin. A new psoralen plus UVA therapy has been developed in which the 8-MOP-containing blood of cutaneous T cell lymphoma (CTCL) pat...

The HIV proviral genome contains two copies of a 16 bp homopurine.homopyrimidine sequence which overlaps the recognition and cleavage site of the Dra I restriction enzyme. Psoralen was attached to the 16-mer homopyrimidine oligonucleotide, d5'(TTTTCT-TTTCCCCCCT)3', which forms a triple helix with this HIV proviral sequence. Two plasmids, containing part of the HIV proviral DNA, with either one ...

Real-time fluorescence detection systems were adapted to identify DNA adducts formed by photogenotoxic phytochemicals. Two assays were developed: the first was based on quantitative polymerase chain reaction (qPCR) while the second used thermal denaturation and renaturation (D-R). Both assays employed yeast DNA, the fluorescent dye SYBR Green and a real-time PCR thermocycler. The furanocoumarin...

Using an oligonucleotide model substrate, we observed two unusual mechanisms of UvrABC endonuclease in the repair of 4,5',8-trimethylpsoralen monoadducts and crosslinks. (i) UvrABC endonuclease usually incises a psoralen monoadduct only on the damaged strand. However, for one of the monoadducts we studied, incision on the complementary undamaged strand was also observed at a very low frequency,...

Light scattering measurements performed on DNA after irradiation in the presence of psoralen clearly show that inter strand cross linkings are present in the macromolecule. In fact after heat denaturation and successive cooling irradiated macromolecule shows a molecular weight practically unchanged while a DNA sample after the same treatment shows a molecular weight half of the intact native DN...

Oral lichen planus (OLP) is a chronic inflammatory disease characterized by relapses and remissions. There is currently no cure for OLP. Treatment is aimed primarily at reducing the length and severity of symptomatic outbreaks. Topical steroids are the first-choice agent for the treatment of symptomatic, active OLP. Other topical agents that have been used in cases resistant to topical steroids...

The purpose of the present study was to prepare psoralen-doxorubicin nanostructured lipid carriers (PSO-DOX-NLC) with better physicochemical properties for further study on its multidrug resistance reversal activity on leukemia cells. PSO-DOX-NLC was synthesized by emulsion evaporation and solidification at a low temperature. PSO-DOX-NLC morphology and particle size were examined using transmis...

Previous work to elucidate the mechanism of crosslink repair by (A)BC excinuclease has shown that a psoralen-crosslinked duplex is selectively incised in the furan-side strand, while a three-stranded structure is incised in the pyrone-side strand of the crosslink. These observations support a sequential incision and recombination model for the complete error-free repair of a psoralen crosslink....