Human papillomavirus infection with anogenital warts in a patient with chronic psoriasis: A case report

Psoriasis is a chronic inflammatory disease with characteristic skin manifestations. Several pathogens can cause flare-ups of psoriasis. The risks of skin infections are increased in patients receiving immunomodulators. A patient with chronic psoriasis presented with human papillomavirus infection and anogenital warts and was treated surgically with acceptable results.

Celecoxib reduces microvessel density in patients treated with nasopharyngeal carcinoma and induces changes in gene expression

BACKGROUND

Celecoxib is a selective cyclooxygenase-2 inhibitor with antitumor and antiangiogenic activity. We sought to determine pharmacodynamic change in tumors of patients with nasopharyngeal carcinoma (NPC) treated with celecoxib.

METHODS

Tumor biopsies were obtained before and after treatment with celecoxib 400 mg b.i.d. for 14 days in patients with newly diagnosed, untreated NPC. Tumor angiogenesis and cell proliferation were assessed by immunohistochemistry and gene expression by microarray analysis. Plasma celecoxib concentrations were obtained on days 8 and 14.

RESULTS

Paired samples were analyzed in 15 patients. Microvessel density was reduced in post-treatment samples and mean celecoxib levels reached therapeutic levels. Thirty-five genes (27 down-regulated, eight up-regulated) were differentially expressed on microarray analysis (p < 0.001). Down-regulated genes included cell cycle regulation-related (cyclin-dependent kinase 2, YES1), transcription factor (TRIP-Br2), whereas the antigen processing and presentation-related gene HLA-DM B was up-regulated.

CONCLUSION

Celecoxib reduced angiogenesis and induced tumor transcriptional changes. Further characterization of these transcriptional changes in vivo is needed to provide further insights into the effects of celecoxib in neoplastic tissue. Our findings provide a rationale for clinical studies aimed at assessing the efficacy of celecoxib in the treatment of NPC.

Screening a library of FDA-approved drugs identifies agents that induce lytic viral infection in EBV-associated tumors

2002

Background: Epstein-Barr virus (EBV) is associated with a variety of tumors including AIDS lymphoma, Burkitt’s lymphoma, nasopharyngeal carcinoma and Hodgkin’s lymphoma. We hypothesized that drugs used in practice might alter viral gene expression in tumor cells in ways that might be important to understand. For example induction of lytic viral gene expression leads to expression of immunodominant CD8 T cell antigens and expression of the viral thymidine kinase (which phosphorylates ganciclovir and other nucleotide analogues). Methods: A library of FDA-approved drugs that includes 2720 agents was screened to identify those that upregulated EBV lytic gene expression. The screen involved a Burkitt’s cell line with a recombinant GFP-EBV that assayed the impact of agents on replication of the complete viral genome, and assay of a lytic promoter reporter construct. Results: The assay identified 146 agents in the whole virus replication assay, 195 agents in the promoter assay, and 54 agents that were active in both assays. Agents with activity could be grouped into 4 families: anti-tubulin drugs, glucocorticoid and other steroid hormones, DNA damaging agents and nucleotide analogues (including cytarabine and gemcitabine), and the proteasome inhibitor bortezomib. Anti-tubulin drugs and nucleotide analogues were less active in thes whole virus assay than the promoter assay whereas bortezomib showed similar activity in both assays. Followup studies confirmed that bortezomib is a potent viral lytic activator that increases expression of the viral thymidine kinase and virion production in several different Burkitt’s lymphoma and primary effusion lymphoma cell lines. Although bortezomib decreases NFKB levels, in vitro investigations with an IKB repressor suggests that inhibition of NFKB alone does not account for lytic activation. Conclusions: Many cancer chemotherapeutic agents are upregulators of EBV lytic expression. Bortezomib is among the most potent. As strategies for using lytic induction therapeutically evolve, these agents may have an important role to play.

No significant financial relationships to disclose.

Dual wavelength demultiplexing by coupling and decoupling of photonic crystal waveguides

We demonstrate that the fundamental mode of the two coupled photonic crystal waveguides (PCWs) can be odd parity in a triangular photonic crystal and their dispersion curves do intersect. Thus, the PCWs are decoupled at the crossing point. By employing the decoupling at the crossing-point frequency and ultra short coupling length for another frequency, we designed a dual-wavelength demultiplexer with a coupling length of only two wavelengths and output power ratio as high as 15 dB. A loop-shape PCW is adapted to eliminate the backward energy flow.

DNA toroids: stages in condensation

The effects of polylysine (PLL) and PLL-asialoorosomucoid (AsOR) on DNA condensation have been analyzed by AFM. Different types of condensed DNA structures were observed, which show a sequence of conformational changes as circular plasmid DNA molecules condense progressively. The structures range from circular molecules with the length of the plasmid DNA to small toroids and short rods with approximately 1/6 to 1/8 the contour length of the uncondensed circular DNA. Single plasmid molecules of 6800 base pairs (bp) condense into single toroids of approximately 110 nm diameter, measured center-to-center. The results are consistent with a model for DNA condensation in which circular DNA molecules fold several times into progressively shorter rods. Structures intermediate between toroids and rods suggest that at least some toroids may form by the opening up of rods as proposed by Dunlap et al. [(1997) Nucleic Acids Res. 25, 3095]. Toroids and rods formed at lysine:nucleotide ratios of 5:1 and 6:1. This high lysine:nucleotide ratio is discussed in relation to entropic considerations and the overcharging of macroions. PLL-AsOR is much more effective than PLL alone for condensing DNA, because several PLL molecules are attached to a single AsOR molecule, resulting in an increased cation density.

Polymerase activities and RNA structures in the atomic force microscope

The structures of the reaction products are the basis for novel polymerase assays using the atomic force microscope (AFM). Polymerases are the enzymes involved in transcription and replication of DNA. Rapid semiquantitative estimates of the activity of DNA polymerases such as Sequenase, Taq polymerase, and AMV reverse transcriptase and RNA polymerases (RNAP) such as Escherichia coli RNAP were obtained from AFM images of the nucleic acids after polymerase reactions. DNA polymerases were assayed via replication of the single-stranded &phi;X-174 virion. RNAP was assayed via transcription, using a rolling circle DNA template that produces long strands of RNA. In some cases, AFM was better than agarose gel electrophoresis for assaying DNA polymerase activity, since aggregation prevented the DNA from entering the agarose gel. Extended molecules of single-stranded RNA synthesized with the rolling circle DNA template showed varied conformations and degrees of stretching. Some structural differences were observed between two RNAs-a ribozyme concatamer and an RNA with 90% purines.

Probing the Saccharomyces cerevisiae centromeric DNA (CEN DNA)-binding factor 3 (CBF3) kinetochore complex by using atomic force microscopy

Yeast centromeric DNA (CEN DNA) binding factor 3 (CBF3) is a multisubunit protein complex that binds to the essential CDEIII element in CEN DNA. The four CBF3 proteins are required for accurate chromosome segregation and are considered to be core components of the yeast kinetochore. We have examined the structure of the CBF3-CEN DNA complex by atomic force microscopy. Assembly of CBF3-CEN DNA complexes was performed by combining purified CBF3 proteins with a DNA fragment that includes the CEN region from yeast chromosome III. Atomic force microscopy images showed DNA molecules with attached globular bodies. The contour length of the DNA containing the complex is approximately 9% shorter than the DNA alone, suggesting some winding of DNA within the complex. The measured location of the single binding site indicates that the complex is located asymmetrically to the right of CDEIII extending away from CDEI and CDEII, which is consistent with previous data. The CEN DNA is bent approximately 55 degrees at the site of complex formation. A significant fraction of the complexes are linked in pairs, showing three to four DNA arms, with molecular volumes approximately three times the mean volumes of two-armed complexes. These multi-armed complexes indicate that CBF3 can bind two DNA molecules together in vitro and, thus, may be involved in holding together chromatid pairs during mitosis.

DNA condensation for gene therapy as monitored by atomic force microscopy

The atomic force microscope (AFM) was used to assay the extent of DNA condensation in approximately 100 different complexes of DNA with polylysine (PL) or PL covalently attached to the glycoproteins asialoorosomucoid (AsOR) or orosomucoid (OR). The best condensation of DNA was obtained with 10 kDa PL covalently attached to AsOR, at a lysine:nucleotide (Lys:nt) ratio of 5:1 or higher. These conditions produce large numbers of toroids and short rods with contour lengths of 300-400 nm. Some DNA condensation into shortened thickened structures was seen with 10 kDa PL attached to AsOR at Lys:nt ratios of 1.6:1 and 3:1. Some DNA condensation was also seen with 4 kDa PL at Lys:nt ratios of 3:1 and higher. Little DNA condensation was seen with PL alone or with PL convalently attached to OR at Lys:nt ratios up to 6:1. AsOR-PL enhanced gene expression in the mouse liver approximately 10- to 50-fold as compared with PL alone.