Intra-Operative Assessment of Cancer with X-Ray Phase Contrast Computed Tomography

X-ray Phase-Contrast Computed Tomography (PC-CT) increases contrast in weakly attenuating samples, such as soft tissues. In Edge-Illumination (EI) PC-CT, phase effects are accessed from amplitude modulation of the x-ray beam using alternating transmitting and attenuating masks placed prior to the sample and detector. A large field of view PC-CT scanner using this technique was applied to two areas of cancer assessment, namely excised breast and esophageal tissue. For the breast tissue, Wide Local Excisions (WLEs) were studied intra-operatively using PC-CT for the evaluation of tumor removal in breast conservation surgery. Images were acquired in 10 minutes without compromising on image quality, showing this can be used in a clinical setting. Longer, higher resolution PC-CT images were also taken, with analysis showing previously undetected thinning of tumor strands. This would allow a second use of the system for “virtual histopathology”, outside of surgery. For the esophagus samples, tissues were taken from esophagectomy surgery, where the lower part of the esophagus is removed, and the stomach relocated. For the assessment of ongoing therapy, accurate staging of tumors in the removed esophagus is essential, with the current gold standard provided by histopathology. PCCT images were acquired on several samples and compare well with histopathology, with both modalities showing similar features. Examples are shown where staging of tumor penetration is possible with PC-CT images alone, which is hoped will be an important step in performing the imaging and staging intra-operatively

Effect of sucralfate on components of mucosal barrier produced by cultured canine epithelial cells in vitro

The mucous gel maintains a neutral microclimate at the epithelial cell surface, which may play a role in both the prevention of gastroduodenal injury and the provision of an environment essential for epithelial restitution and regeneration after injury. Enhancement of the components of the mucous barrier by sucralfate may explain its therapeutic efficacy for upper gastrointestinal tract protection, repai, and healing. We studied the effect of sucralfate and its major soluble component, sucrose octasulfate (SOS), on the synthesis and release of gastric mucin and surface active phospholipid, utilizing an isolated canine gastric mucous cells in culture. We correlated these results with the effect of the agents on mucin synthesis and secretion utilizing explants of canine fundus in vitro . Sucralfate and SOS significantly stimulated phospholipid secretion by isolated canine mucous cells in culture (123% and 112% of control, respectively.) Indomethacin pretreatment siginificantly inhibited the effect of sucralfate, but not SOS, on the stimulation of phospholipid release. Administration of either sucralfate or SOS to the isolated canine mucous cells had no effect upon mucin synthesis or secretion using a sensitive immunoassay. Sucralfate and SOS did not stimulate mucin release in the canine explants; sucralfate significantly stimulated the synthesis of mucin, but only to 108% of that observed in untreated explants. No increase in PGE 2 release was observed after sucralfate or SOS exposure to the isolated canine mucous cells. Our results suggest sucralfate affects the mucus barrier largely in a qualitative manner. No increase in mucin secretion or major effect on synthesis was notd, although a significant increase in surface active phospholipid release was observed. The lack of dose dependency of this effect, along with the results of the PGE 2 assay, suggests the drug may act through a non-receptor-mediated mechanism to perturb the cell membrane and release surface active phospholipid. The enhancement of phospholipid release by sucralfate to augment the barrier function of gastric mucus may, in concert with other effects of the drug, strrengthen mucosal barrier function.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44415/1/10620_2005_Article_BF01308079.pd

Analysis of the conversion of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-alpha-aminobutyrate by active-site mutants of Aspergillus nidulans isopenicillin N synthase.

BACKGROUND: Penicillins and cephalosporins constitute a major class of clinically useful antibiotics. A key step in their biosynthesis involves the oxidative cyclisation of delta-(Lalpha-aminoadipoyl)-L-cysteinyl-D-valine to isopenicillin N by isopenicillin N synthase (IPNS). This chemically remarkable transformation has been extensively studied using substrate analogues. The conversion of an analogue in which the valine is replaced by alpha-aminobutyrate results in three products, two epimeric penams and a cepham. The ratio of these products in reactions catalysed by four different IPNS isozymes has been used previously to probe the thermicity of the chemical mechanism. But how IPNS restricts the products from the natural substrate to a single penam (isopenicillin N) has remained unknown. RESULTS: A key active-site residue, Leu223, identified according to a model of enzyme-substrate binding, has been altered to sterically less demanding residues. As the steric constraints on the upper part of the active site are reduced, the ratio of the beta-methyl penam to the cepham increases when the alpha-aminobutyrate-containing substrate analogue is used. These results suggest a mechanism for processing of the natural substrate in which IPNS uses steric control to restrict the conformational freedom of an intermediate such that the only product is the penam. CONCLUSIONS: Using steric pressure to control conformation, and hence to disfavour reactions leading to alternate products, is probably the result of evolutionary selection for a biologically active product at the expense of biologically inactive byproducts. It is likely that this sort of enzymatic catalysis is used in situations where substrate conversion is highly exothermic and a variety of products are possible

Are metal stents effective for palliation of malignant dysphagia and fistulas?

Background. One of the available treatments for unresectable oesophagogastric malignancies is the insertion of metal stents. Aims. We evaluated prospectively 147 patients suffering from malignant dysphagia and/or fistula, after inserting a self-expandable metal stent. Patients and methods. The study included 147 patients (87 males, mean age 73 years). Dysphagia before and after stent placement was scored. Patients were divided in two groups according to dysphagia grade: group A (grade 0, 1) and group B (grades 2, 3, 4). Three types of stents were used: the Ultraflex stent (covered and uncovered) and the Flamingo one (covered). The total number of self-expandable metal stents placed was 183. A total of 92 of them were inserted following the combined endoscopic and fluoroscopic approach (42 by injecting lipiodol), while 91 were placed under endoscopic control only. Early and late complications were evaluated. Results. Mean dysphagia score in group A, I day and I month after the procedure, was slightly reduced from 0.8 to 0.5/0.6 (p = NS), respectively. However, there was a statistically significant improvement (p < 0.001) of mean dysphagia score in group B, from 2.4 initially to 1.1/1.4. Early complications occurred in 37 cases, late ones in 51. According to severity, minor complications occurred in 24 patients, major in 42, while life-threatening ones in 22. Survival ranged from I to 611 days and 1-week mortality was 9%. Stent-related death occurred in six patients. Conclusions. All kinds of endoscopic methods used for stenting in the present study were easy to perform even on an out-patient basis. Insertion of self-expandable metal stents is effective in patients with dysphagia scores greater than or equal to 2. It might not clinically improve patients with dysphagia score < 2, so selection of patients for stenting is essential to avoid unnecessary procedures. Moreover, their high cost, high complication rates and low overall survival may improve following better selection criteria. (C) 2003 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Science Ireland Ltd. All rights reserved

A phase I study of OncoVEX(GM-CSF), a second-generation oncolytic herpes simplex virus expressing granulocyte macrophage colony-stimulating factor

PURPOSE: To conduct a phase I clinical trial with a second-generation oncolytic herpes simplex virus (HSV) expressing granulocyte macrophage colony-stimulating factor (Onco VEXGM-CSF) to determine the safety profile of the virus, look for evidence of biological activity, and identify a dosing schedule for later studies. EXPERIMENTAL DESIGN: The virus was administered by intratumoral injection in patients with cutaneous or s.c. deposits of breast, head and neck and gastrointestinal cancers, and malignant melanoma who had failed prior therapy. Thirteen patients were in a single-dose group, where doses of 10(6), 10(7), and 10(8) plaque-forming units (pfu)/mL were tested, and 17 patients were in a multidose group testing a number of dose regimens. RESULTS: The virus was generally well tolerated with local inflammation, erythema, and febrile responses being the main side effects. The local reaction to injection was dose limiting in HSV-seronegative patients at 10(7) pfu/mL. The multidosing phase thus tested seroconverting HSV-seronegative patients with 10(6) pfu/mL followed by multiple higher doses (up to 10(8) pfu/mL), which was well tolerated by all patients. Biological activity (virus replication, local reactions, granulocyte macrophage colony-stimulating factor expression, and HSV antigen-associated tumor necrosis), was observed. The duration of local reactions and virus replication suggested that dosing every 2 to 3 weeks was appropriate. Nineteen of 26 patient posttreatment biopsies contained residual tumor of which 14 showed tumor necrosis, which in some cases was extensive, or apoptosis. In all cases, areas of necrosis also strongly stained for HSV. The overall responses to treatment were that three patients had stable disease, six patients had tumors flattened (injected and/or uninjected lesions), and four patients showed inflammation of uninjected as well as the injected tumor, which, in nearly all cases, became inflamed. CONCLUSIONS: Onco VEXGM-CSF is well tolerated and can be safely administered using the multidosing protocol described. Evidence of an antitumor effect was seen