The light-activated, nucleic acid-binding drugs, psoralens, were used in conjunction with a 365-nm laser microbeam to selectively bind to any nucleic acids in the centriolar region. 4'-aminomethyl-4,5',8--trimethyl-psoralen (AMT) has a high affinity for both RNA and DNA and can be shown to cause mitotic abortion when centriolar regions of prophase PTK2 cells and reacted with AMT and 365-nm lase...

AIM Evaluation of narrow band ultraviolet B (NB UVB 311 nm) in the treatment of vitiligo by two independent studies. The first study compared NB UVB with a well-established therapeutic modality, psoralen ultraviolet A (PUVA), and the second study was conducted to find out whether psoralen might add to its efficacy. METHODS In the first study, 15 patients were exposed on the left half of their...

We have developed a new biochemical method to isolate a homogeneous population of RNA polymerase II (RNA pol II) elongation complexes arrested at a DNA damage site. The method involves triple-helix formation at a predetermined site in DNA template with a third strand labeled with psoralen at its 5'-end and a biotin at the 3'-end. After triplex formation and near-ultraviolet irradiation (360 nm)...

Impaired DNA damage repair, especially deficient transcription-coupled nucleotide excision repair, leads to segmental progeroid syndromes in human patients as well as in rodent models. Furthermore, DNA double-strand break signalling has been pinpointed as a key inducer of cellular senescence. Several recent findings suggest that another DNA repair pathway, interstrand cross-link (ICL) repair, m...

Triple helix forming oligonucleotides can direct DNA damaging agents at specific sites in an intact double helix. In our study, triple helix formation was demonstrated in a SV40 based shuttle vector treated with psoralen linked to a 22-mer purine rich oligonucleotide. UVA irradiation caused a covalent linkage of the oligonucleotide through the psoralen to the mutational supF marker gene of the ...

Psoralea corylifolia L. (Fabaceae) is a widely used medical plant in China. This study was designed to screen and identify bioactive compounds with anticancer activity from the seeds of Psoralea corylifolia L. One volatile fraction (fraction I) and three other fractions (fraction II, III, IV) from methanol extraction of P. corylifolia L. were obtained. Bioactivities of these fractions were eval...

Interstrand crosslink (ICL)-inducing agents block the separation of the two DNA strands. They prevent transcription and replication and are used in clinics for the treatment of cancer and skin diseases. Here, we have introduced a single psoralen ICL at a specific site in plasmid DNA using a triplex-forming-oligonucleotide (TFO)-psoralen conjugate and studied its repair in Xenopus egg extracts t...

The effect of arachidonic acid (AA) combined with UVA irradiation was studied in a model system mimicking phototherapy PUVA (psoralen+UVA) ex vivo in vitro. The contribution of damage to the plasma membrane by PUVA was tested on human lymphocytes derived from healthy donors. The effect of arachidonic acid (AA) combined with UVA irradiation was compared with that of a psoralen photoadduct to AA ...

There is a significant risk of severe graft-versus-host disease (GVHD) and graft failure after unrelated umbilical cord blood transplantation (CBT) if donor-recipient pairs are mismatched at major histocompatibility complex (MHC) loci. To mitigate these risks after MHC-mismatched CBT, we infused psoralen-treated, photochemically inactivated, mature donor T-lymphocytes with MHC (H2-haplotype) mi...

In a previous paper 1, we reported that cells of the Ehrlich ascites tumor lose their in vivo ability to induce tumors when irradiated with long wave­ length ultraviolet (365 nm) in the presence of very small amounts of the so called “skin-photosensi­ tizing” furocoumarins (psoralens). Studies in this laboratory (Institute of Pharma­ ceutical Chemistry) have shown that these photo­ sensitizing ...