Citations

Abstract Anal canal pressure gradient and ileal pouch motor activity were studied in continent and incontinent patients after ileal pouch-anal anastomosis. A multichannel microtransducer catheter was positioned in eight continent and eight incontinent patients 15 months or more after operation and 24-h ambulatory motor activity recorded. Resting anal pressures were significantly lower for incontinent patients during the day and night. The frequency of high-pressure waves was identical in both groups, but peak pressures were higher for incontinent patients. For continent patients, each high-pressure wave was accompanied by a rapid increase in anal canal pressure such that pressure in the pouch was always less than that in the anal canal. For incontinent patients this response was often absent. Incontinent patients had lower resting pressure, more prolonged anal canal relaxation, higher amplitude high-pressure waves and a non-responsive anal canal; the anal canal pressure gradient was therefore frequently reversed.

Abstract Electrocautery is widely used for dissection of tissues and cauterization of blood vessels. A visible plume of smoke is produced, which has an unpleasant odour and can induce acute and chronic inflammatory changes in the respiratory tract'. Airborne particles arc not effectively filtered or evacuated by operating room scavenging systems and facial masks only offer protection from large particles. Little is known about the chemical composition of this smoke and the health risks to the operating room staff have not been identified. The aim of this study was to determine the chemical composition of electrocautery smoke produced in the course of standard colorectal surgery.

Abstract Purpose: To evaluate the effects of combining the multiple receptor tyrosine kinase inhibitor AEE788 and histone deacetylase (HDAC) inhibitors on cytotoxicity in a broad spectrum of cancer cell lines, including cisplatin-resistant ovarian adenocarcinoma cells. Experimental Design: Multiple cancer cell lines were treated in vitro using AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A), either alone or in combination. Effects on cytotoxicity were determined by growth and morphologic assays. Effects of the combination on cell signaling pathways were determined by Western blotting, and the results were confirmed using pathway-specific inhibitors and transfection of constitutively active proteins. Results: Cell treatment with AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A) in combination resulted in synergistic induction of apoptosis in non–small cell lung cancer (MV522, A549), ovarian cancer (SKOV-3), and leukemia (K562, Jurkat, and ML-1) cells and in OV202hp cisplatin-resistant human ovarian cancer cells. AEE788 alone or in combination with LBH589 inactivated mitogen-activated protein kinase (MAPK) and Akt cascades. Inhibition of either MAPK and/or Akt enhanced LBH589-induced apoptosis. In contrast, constitutively active MAPK or Akt attenuated LBH589 or LBH589 + AEE788–induced apoptosis. Increased apoptosis was correlated with enhanced reactive oxygen species (ROS) generation. The free radical scavenger N-acetyl-l-cysteine not only substantially suppressed the ROS accumulation but also blocked the induction of apoptosis mediated by cotreatment with AEE788 and LBH589. Conclusion: Collectively, these results show that MAPK and Akt inactivation along with ROS generation contribute to the synergistic cytotoxicity of the combination of AEE788 and HDAC inhibitors in a variety of human cancer cell types. This combination regimen warrants further preclinical and possible clinical study for a broad spectrum of cancers.

A subset of proteins that transit the endosomal system are directed into the intralumenal vesicles of multivesicular bodies (MVBs). MVB formation is critical for a variety of cellular functions including receptor down-regulation, viral budding, antigen presentation, and the generation of lysosome-related organelles. Entry of transmembrane proteins into the intralumenal vesicles of a MVB is a highly regulated process that is positively modulated by covalent modification of cargoes with ubiquitin. To identify additional MVB sorting signals, we examined the previously described ubiquitination-independent MVB cargo Sna3. Although Sna3 ubiquitination is not essential, Sna3 MVB sorting is positively modulated by its ubiquitination. Examination of MVB sorting determinants within a form of Sna3 lacking all lysine residues identified two critical regions: an amino-terminal tyrosine-containing region and a carboxyl-terminal PPAY motif. This PPAY motif interacts with the WW domains of the ubiquitin ligase Rsp5, and mutations in either the WW or, surprisingly, the HECT domains of Rsp5 negatively impacted MVB targeting of lysine-minus Sna3. These data indicate that Rsp5 function is required for MVB targeting of Sna3 in a capacity beyond cargo ubiquitination. These results uncover a series of determinants impacting Sna3 MVB sorting, including unexpected roles for Rsp5.

The multivesicular body (MVB) sorting pathway impacts a variety of cellular functions in eukaryotic cells. Perhaps the best understood role for the MVB pathway is the degradation of transmembrane proteins within the lysosome. Regulation of cargo selection by this pathway is critically important for normal cell physiology, and recent advances in our understanding of this process have highlighted the endosomal sorting complexes required for transport (ESCRTs) as pivotal players in this reaction. To better understand the mechanisms of cargo selection during MVB sorting, we performed a genetic screen to identify novel factors required for cargo-specific selection by this pathway and identified the Mvb12 protein. Loss of Mvb12 function results in differential defects in the selection of MVB cargoes. A variety of analyses indicate that Mvb12 is a stable member of ESCRT-I, a heterologous complex involved in cargo selection by the MVB pathway. Phenotypes displayed upon loss of Mvb12 are distinct from those displayed by the previously described ESCRT-I subunits (vacuolar protein sorting 23, -28, and -37), suggesting a distinct function than these core subunits. These data support a model in which Mvb12 impacts the selection of MVB cargoes by modulating the cargo recognition capabilities of ESCRT-I.

ABSTRACT Staphylococci, common orthopedic pathogens, form antibiotic-resistant biofilms. Polymethylmethacrylate (PMMA) beads loaded with the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP) were implanted in rats and shown to prevent methicillin-resistant Staphylococcus aureus infection. RIP release was bimodal, typical of previously-tested antibiotics. These results suggest that RIP-PMMA warrants further evaluation for management of orthopedic infections caused by staphylococci.

Abstract 17-Allylamino-demethoxygeldanamycin (17-AAG), currently in phase I and II clinical trials as an anticancer agent, binds to the ATP pocket of heat shock protein (Hsp90). This binding induces a cellular stress response that up-regulates many proteins including Hsp27, a member of the small heat shock protein family that has cytoprotective roles, including chaperoning of cellular proteins, regulation of apoptotic signaling, and modulation of oxidative stress. Therefore, we hypothesized that Hsp27 expression may affect cancer cell sensitivity to 17-AAG. In colony-forming assays, overexpression of Hsp27 increased cell resistance to 17-AAG whereas down-regulation of Hsp27 by siRNA increased sensitivity. Because Hsp27 is known to modulate levels of glutathione (GSH), we examined cellular levels of GSH and found that it was decreased in cells transfected with Hsp27 siRNA when compared with control siRNA. Treatment with buthionine sulfoximine, an inhibitor of GSH synthesis, also sensitized cells to 17-AAG. Conversely, treatment of Hsp27 siRNA–transfected cells with N-acetylcysteine, an antioxidant and GSH precursor, reversed their sensitivity to 17-AAG. A cell line selected for stable resistance to geldanamycin relative to parent cells showed increased Hsp27 expression. When these geldanamycin- and 17-AAG-resistant cells were transfected with Hsp27 siRNA, 17-AAG resistance was dramatically diminished. Our results suggest that Hsp27 up-regulation has a significant role in 17-AAG resistance, which may be mediated in part through GSH regulation. Clinical modulation of GSH may therefore enhance the efficacy of Hsp90-directed therapy. (Cancer Res 2006; 66(22): 10967-75)

AbstractPurpose: The aim of the present study was to evaluate the effects of piroxicam, a widely used nonsteroidal anti-inflammatory drug, alone and in combination with cisplatin (CDDP), on cell growth of mesothelioma cells.Experimental Design: Cell proliferation, cell cycle analysis, and microarray technology were done on MSTO-211H and NCI-H2452 cells treated with piroxicam. Moreover, the effects of piroxicam and CDDP on tumor growth and survival of mouse xenograft models of mesothelioma were determined.Results: Piroxicam treatment of MSTO-211H and NCI-H2452 cells resulted in a significant inhibition of proliferation. Cell cycle analysis revealed that there was an increase in the rate of apoptosis in MSTO-211H cells and an increase in the cells accumulating in G2-M in NCI-H2452. Moreover, a marked tumor growth inhibition and an extended survival of mice treated with a combination of piroxicam and CDDP in MSTO-211H cell–induced peritoneal mesotheliomas was observed. Last, GeneChip array analysis of MSTO-211H mesothelioma cell line revealed that piroxicam treatment caused up-regulation of metabolic pathway–associated genes and down-regulation of genes related to RNA processing apparatus. Of note, epidermal growth factor receptor, one of the new biological targets of chemotherapy for mesothelioma, was down-regulated and HtrA1, a serine protease recently shown to be an endogenous mediator of CDDP cytotoxicity, was up-regulated following piroxicam treatment both in vitro and in vivo.Conclusion: These data suggest that piroxicam sensitizes mesothelioma cells to CDDP-induced cytotoxicity by modulating the expression of several target genes. Therefore, piroxicam in combination with CDDP might potentially be useful in the treatment of patients with mesothelioma.