Wavelength dependency of photo-inactivation and photoinduced reverse mutation of Escherichia coli sensitized with 8-methoxypsoralen, and wavelength dependency of photoinduction of lambda prophage from the sensitized lysogen were measured in a range of 298 to 400 nm. The most efficient sensitization for these biological effects was observed between 320 and 340 nm. In the presence of 8-methyoxyps...

A composite system of four dosimeter materials, nalidixic acid (NDA), polysulphone, 8-methoxypsoralen (8-MOP) and phenothiazine, is presented for the passive measurement of the UV spectrum. The properties of the materials were investigated and found to be suitable to allow the materials to be applied in a system to evaluate the UV spectrum. The evaluation of the spectrum reduces by 70% the erro...

Two S-adenosyl-L-methionine:furanocoumarin O-methyltransferases of R. graveolens, acting at the 5- and 8-hydroxyl of the psoralen nucleus, were completely resolved by adsorption on a general affinity ligand, 5-(3-carboxypropanamido) xanthotoxin, followed by specific desorption by bergaptol and xanthotoxol, respectively. The 5-O-methyltransferase was purified 450-fold by this procedure, the 8-O-...

A method is described for determination of 8-methoxypsoralen to 0.2 mL of suction-blister fluid or 1 mL of serum from psoriatic patients being treated with this drug. The drug is extracted from the biological matrix at pH 9.0 with a mixture of dichloromethane and light petroleum ether. 5-Methoxypsoralen is used as internal standard. Separation and quantitation are performed on a "high-performan...

We have examined the interactions of UvrABC endonuclease with DNA containing the monoadducts of 8-methoxypsoralen (8-MOP) and 4,5',8-trimethylpsoralen (TMP). The UvrA and UvrB proteins were found to form a stable complex on DNA that contains the psoralen monoadducts. Subsequent binding of UvrC protein to this complex activates the UvrABC endonuclease activity. As in the case of incision at pyri...

A total of six coumarins, bergapten (1), xanthotoxin (2), imperatorin (3), isoimperatorin (4), phellopterin (5) and archangelicin (6), have been isolated from an n-hexane extract of the seeds of Angelica archangelica. The results of comprehensive 2D NMR analyses of archangelicin are discussed.

For pharmaceuticals, current regulatory guidance for photosafety testing states that studies are warranted for drug candidates that both absorb light in the range of 290-700 nm and that are either applied topically or reach the skin or eyes by systemic exposure. In contrast to standard genotoxicity evaluations, where a positive (or equivocal) result in vitro can be placed into context with addi...

In the presence of sulfhydryl compounds nitracrine, an anticancer drug, binds covalently to DNA. The accessibility of DNA in chromatin both to nitracrine and to 8-methoxypsoralen, which was used as a reference compound in this study, when assayed in NaCl concentrations from 0 to 2 M show similar characteristics. The initial decrease reaches a minimum at 0.15 M NaCl above which dissociation of n...

BACKGROUND Although nearly half of bladder cancer cases are due to smoking, the cause of nearly half is unexplained. PURPOSE This study aims to determine whether an inverse association exists between ultraviolet B (UVB) irradiance and incidence rates of bladder cancer worldwide. METHODS This study used an ecologic approach. Age-adjusted incidence rates of bladder cancer from 2002 were obtai...

We have synthesized a series of 8-[3H]methoxypsoralens in which methyl and hydrogen are systematically varied at the 4- and 5'-positions. Analysis of the products resulting from the photoaddition of these four psoralens with the nucleic acid poly(dA-dT) reveals that the product distribution depends on the presence or absence of a 4-methyl substituent. Compounds with the 4-methyl group show an o...