Novel management of pseudomonas biofilm-like structure in a post-pneumonectomy empyema.

We present a patient with a post-pneumonectomy empyema refractory to surgical debridement and systemic antibiotics. The patient initially presented with a bronchopleural fistula and pneumothorax secondary to tuberculosis (TB) destroyed lung, which required a pneumonectomy with Eloesser flap. Ongoing pleural infection delayed the closure of the Eloesser flap, and thoracoscopic inspection of his chest cavity revealed a green, mucous biofilm-like structure lining the postpneumonectomy pleural cavity.

Hepatic artery infusion pump (HAIP) therapy in combination with targeted delivery of IL-12 for patients with metastatic colorectal cancer or intrahepatic cholangiocarcinoma: a phase II trial protocol.

Background: Treatment of advanced liver tumors remains challenging. Although immune checkpoint inhibition has revolutionized treatment for many cancers, responses in colorectal liver metastases and biliary tract cancers remain suboptimal. Investigation into additional immunomodulatory therapies for these cancers is needed.

The induction of partial resistance to photodynamic therapy by the protooncogene BCL-2.

Photodynamic therapy (PDT) is an efficient inducer of apoptosis, an active form of cell death that can be inhibited by the BCL-2 oncoprotein. The ability of BCL-2 to modulate PDT-induced apoptosis and overall cell killing has been studied in a pair of Chinese hamster ovary cell lines that differ from one another by a transfected human BCL-2 gene in one of them (Bissonnette et al, Nature 359, 552-554, 1992). Cells were exposed to the phthalocyanine photosensitizer Pc 4 and various fluences of red light.

Differential dependence on chromatin structure for copper and iron ion induction of DNA double-strand breaks.

The induction of DNA DSB (double-strand breaks) in isolated nuclear chromatin by Cu(II) or Fe(II)-EDTA in the presence of H2O2 and ascorbate has been compared to DSB induction by gamma-radiation. V79 nuclei embedded in agarose plugs were treated with each agent on ice, and the resultant DNA fragments were analyzed by pulsed-field gel electrophoresis. In the absence of low molecular weight radical scavengers, both irradiation and treatment with iron ion induced random DSB, as judged by the size distribution of DNA fragments, and the yield of DSB in each case was enhanced by either the expansion of chromatin (approximately 5-fold) or the removal of histones (21-25-fold) before treatment.

Induction of DNA damage in gamma-irradiated nuclei stripped of nuclear protein classes: differential modulation of double-strand break and DNA-protein crosslink formation.

The influence of chromatin proteins on the induction of DNA double-strand breaks (dsb) and DNA-protein crosslinks (dpc) by gamma-radiation was investigated. Low molecular weight non-histone proteins and classes of histones were extracted with increasing concentrations of NaCl, whereas nuclear matrix proteins were not extractable even by 2.0 M NaCl.

Copper ion-mediated sensitization of nuclear matrix attachment sites to ionizing radiation.

Exposure of mammalian cells to ionizing radiation induces nuclear matrix proteins and their attached transcribing DNA sequences to form cross-links. To characterize the cellular and matrix components necessary for DNA-protein crosslink (DPC) formation, DPC yields have been examined in isolated nuclear matrices and in the intermediate steps during cell fractionation. It was found that, in both unirradiated and irradiated cells, all components of DPC are retained in isolated nuclei, and the formed DPC are retained as well during the cell fractionation procedure resulting in nuclear matrices.

Formation of DNA-protein cross-links in mammalian cells by levuglandin E2.

Levuglandin E2 (LGE2), a rearrangement product derived from the prostaglandin endoperoxide, PGH2, causes repair-resistant DNA-protein cross-links and cell death (LD50 = 230 nM) in V79 Chinese hamster lung fibroblasts. The half-life for sequestration of LGE2 by covalent binding to cellular nucleophiles is at least an hour for 10 microM LG. This suggests that the in vivo production and distribution of free LGs should be measurable on this time scale.

Chromatin compaction and the efficiency of formation of DNA-protein crosslinks in gamma-irradiated mammalian cells.

Chromatin has been prepared from Chinese hamster V79 cell nuclei by successive suspension and sedimentation in buffers of decreasing ionic strength. For buffer concentrations from 50 to 1 mM, the resultant chromatin maintained a normal histone content, nucleosomal organization, and attachment to the nuclear matrix; however, as the buffer concentration was reduced from 50 to 10 and 1 mM, the higher-order chromatin structures became increasingly relaxed. Fully expanded chromatin is 5- to 10-fold more susceptible to the induction of DNA-protein crosslinks (DPCs) by gamma radiation than is chromatin residing in living interphase cells.

Post-treatment interactions of photodynamic and radiation-induced cytotoxic lesions.

The interaction of chloroaluminum phthalocyanine-sensitized photodynamic treatment and gamma-irradiation was studied in confluent murine L929 fibroblasts. When the cells were given the combined treatments and immediately subcultured for determination of cell survival by colony formation, the data indicate independent actions of each modality. However, when subculture was delayed for 1 h, a substantial fraction of cells treated with a sub-lethal dose of PDT followed by 5 Gy gamma-radiation detached from the monolayer.

The fate of DNA-protein crosslinks formed in gamma-irradiated metaphase cells.

The induction of DNA-protein crosslinks (DPC) was compared in gamma-irradiated metaphase and asynchronous Chinese hamster V79 cells. Unirradiated metaphase cells were found to have a higher level of background DPC than unirradiated asynchronous cells, and the metaphase cells were less susceptible to radiation-induced DPC production than were asynchronous cells. SDS-PAGE analysis of crosslinked proteins prepared from the two cell populations, both irradiated and unirradiated, showed very similar protein patterns.

Formation and repair of DNA-protein crosslinks in newly replicated DNA.

The production and removal of gamma-radiation-induced DNA-protein crosslinks (DPC) in nuclear matrix-associated newly replicated DNA were examined, as well as the relationship of DPC to DNA replication. In unirradiated, exponentially growing Chinese hamster V79 cells, DNA pulse labeled with [3H]thymidine was observed to be bound preferentially to protein. The pulse-labeled DNA subsequently became dissociated from protein.

Comparison of DNA-protein cross-links induced by 4'-(9-acridinylamino)-methanesulfon-m-anisidide and by gamma-radiation.

The antitumor agent 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) inhibits topoisomerase II activity through the formation of a complex of DNA and covalently bound enzyme which, upon protein denaturation, yields DNA breaks (single strand breaks). In the present study, this complex served as a standard for analysis of radiation-induced DNA-protein cross-links (DPC). Following the treatment of exponentially growing mouse L929 cells with 0-100 ng/ml of m-AMSA for 1 h, a linear dose-dependent increase was found in the amount of DNA retained on nitrocellulose filters during subsequent analysis.

Repair of chromatin damage in glutathione-depleted V-79 cells: comparison of oxic and hypoxic conditions.

We have assessed the effects of two radiomodifying conditions, glutathione (GSH) depletion and hypoxia, on the formation and repair of radiation-induced chromatin damage, specifically DNA-protein cross-links (DPC). As measured by a nitrocellulose filter-binding assay, untreated V79 cells contain a low level of DPC (1-1.5% of the cellular DNA).

Inhibition of radiation-induced DNA-protein cross-link repair by glutathione depletion with L-buthionine sulfoximine.

Cells depleted of their glutathione (GSH) by treatment with L-buthionine sulfoximine (BSO) are more sensitive to ionizing radiation and chemotherapeutic agents. To assess the effects of GSH depletion on repair of radiation-induced DNA damage, we have determined DNA-protein cross-links (DPC) in A549 cells by a nitrocellulose filter binding assay. Untreated A549 cells have a low level of DPC (0.

Modification of DNA damage in transcriptionally active vs. bulk chromatin.

Our previous experiments have demonstrated that regions of nuclear chromatin, containing transcriptionally active DNA sequences and associated with the nuclear matrix, are hypersensitive to the production of both single-strand breaks and DNA-protein cross-links upon gamma-irradiation of exponentially growing mammalian cells. In this study, we have irradiated Chinese hamster V79 cells in buffered saline with or without DMSO to scavenge hydroxyl radicals and in buffered salines of various tonicities to expand or condense chromatin. The yield of DNA-protein cross-links was assayed by a nitrocellulose filter binding technique and the DNA recovered from the cross-links hybridized to 125I-poly(A+)RNA to determine the relative frequency of transcriptionally active sequences in the cross-links compared to the bulk DNA.

Nuclear matrix proteins are crosslinked to transcriptionally active gene sequences by ionizing radiation.

Unirradiated, exponentially growing Chinese hamster cells contain a low level (less than 5%) of their DNA firmly bound to protein, as measured by a filter-binding assay. That fraction of DNA is highly enriched in sequences which hybridize to poly(A+)RNA or ribosomal RNA. After 60 Gy gamma irradiation, the additional crosslinked DNA is also enriched in transcriptionally active sequences compared to bulk DNA, while DNA crosslinked by uv radiation has a frequency of active sequences which is no higher than the bulk DNA.

Differential processing of ultraviolet or ionizing radiation-induced DNA-protein cross-links in Chinese hamster cells.

The yield and repairability of DNA-protein cross-links have been compared after gamma- or U.V.-irradiation of Chinese hamster V79-379 lung fibroblasts.

Gamma radiation as a probe of chromatin structure: damage to and repair of active chromatin in the metaphase chromosome.

Cobalt-60 gamma radiation has been employed as a means of preferentially damaging actively transcribing chromatin within interphase and metaphase Chinese hamster V79-379 lung fibroblasts. The single-strand size distribution and break frequency of bulk 3H-labeled DNA have been compared to those same parameters for active sequences, i.e.