Dynamic viscoelasticity of polyacetylene during oxidation

Dynamic viscoelasticity measurements at 90°C suggest an oxidation process for pristine polyacetylenes (PA's). For cis-rich PA, the oxidation can be divided into three regions: surface oxidation, bulk oxidation, and crosslinking. Crosslinking also occurs at the end of the surface oxidation period but does not occur in the bulk reaction period. For trans-rich PA, oxygen doping was complete after the first 15 min and occurred to a smaller extent than that of the cis-rich PA. The rate of reaction of trans PA chains with oxygen is slow in comparision to that of crosslinking by radical combination or addition reactions with the PA chains. In the case of trans PA the concentration of radical chains formed by reaction with oxygen retains a steady value after the initial period up to the end of oxidation.     

Video-assisted thoracoscopic surgery in the treatment of complicated parapneumonic effusions or empyemas: outcome of 234 patients

STUDY OBJECTIVE: To review our experience in treatment of complicated parapneumonic effusion and pleural empyema by video-assisted thoracoscopic surgery (VATS). DESIGN: Retrospective chart review. SETTING: Taiwanese medical centers. PATIENTS: A total of 234 patients (108 women, 126 men; median age, 51 years; range, 0.75 to 84 years) underwent procedures for parapneumonic effusion (145 patients) or pleural empyema (89 patients) between May 1995 and December 2003. All patients had chest radiographs, and 188 patients (80.3%) underwent preoperative CT or sonography. More than 85% (200 patients) received preoperative diagnostic or therapeutic thoracentesis, tube thoracostomy, or fibrinolytics. Indications for VATS included empyema refractory to medical control or peel or multiloculated exudates per CT and chest tapping. INTERVENTIONS: Septal lysis and debridement irrigation through one port (31 patients, 13.2%), decortication and debridement through two or three ports (179 patients, 76.5%), or rib resection or larger utility incision for decortication and drainage (24 patients, 10.3%). RESULTS: Mean +/- SD procedural time was 64.3 +/- 22.5 min (range, 26 to 244 min). Sixteen patients (6.8%) needed further surgery for empyema (9 patients required open drainage or thoracoplasty, and 7 patients needed redecortication or repair of bronchopleural fistula). There were no intraoperative deaths and only eight (3.4%) perioperative deaths (< 30 days), which were mostly unrelated to surgery. Of the 234 patients, 202 patients (86.3%) achieved satisfactory results with VATS treatment. Patients requiring open decortication or repeat procedures (40 patients) had a longer mean duration of preoperative symptoms, longer mean duration of preoperative hospitalization, and a higher ratio of pleural empyema (vs complicated parapneumonic effusion) than patients undergoing simple VATS. CONCLUSIONS: VATS is safe and effective for treatment of complicated parapneumonic effusion and pleural empyema. Earlier intervention with VATS can produce better clinical results. A prospective study should be done to identify optimal timing and settings for VATS treatment for both complicated parapneumonic effusion and pleural empyema.     

A novel surgical correction through a small transverse incision for pectus excavatum

Surgical correction of pectus excavatum (PE) has been well established since Ravitch's publication in 1949. However, Ravitch's procedure, even if modified, was associated with the relatively radical nature of the operation. The aim of this study was to report our early experience and results in treatment of PE by a novel less invasive surgical technique through a small skin incision. From 1998 to 2003, a novel surgical correction through a small transverse incision was performed for 11 patients with PE, including 9 males and 2 females. The mean age was 9.2 years (range, 3 to 17 years). The less invasive surgical technique consisted of a small transverse skin incision over the deepest part of the PE deformity, subcutaneous dissection to the margin of the depressed deformity, elevation of pectoralis musculature from the midline toward the lateral border of the operative field, subperichondrial resection of the short segment (1 to 2 cm) of the involved costal cartilages, detachment of the xiphoid process and elevation of the sternum with sharp or blunt dissection, retrosternal titanium miniplate strutting, placement of drainage tubes in the mediastinum or pleural spaces, and closure of the operative wound. No sternal osteotomy was performed in this series. The average length of the skin incision was 3.2 cm. The number of the resected cartilages varied from 3 to 6 ribs on each side. The average blood loss was 41 mL (range, 10 to 80 mL), and the operation time was 3.1 hours. The duration of hospitalization was 4.4 days on average. There was no surgical complication or mortality. All patients were satisfied with their cosmesis, and no migration of the retrosternal strut was found in chest radiographs until the date of analysis. This less invasive surgical technique, which did not require osteotomy, could be effectively performed through a small skin incision and was associated with steady recovery of chest wall deformity, as well as excellent cosmetic results.     

Associated microsatellite alterations in mitochondrial DNA and in TP53 in thoracic esophageal squamous cell carcinoma

Chemoresistance and self-renewal of cancer stem cells (CSC), found in many tumors including pancreatic ductal adenocarcinoma (PDAC), are believed to underlie tumor mass regrowth. The distribution of cells carrying the putative stem-cell markers CD133, Nestin, Notch1-4, Jagged1 and 2, ABCG2 and aldehyde dehydrogenase (ALDH1) was assessed immunohistochemically using PDAC and normal pancreas tissue microarrays. The immunoreactivity was semi-quantitatively graded against the normal pancreas and was correlated with the differentiation grade and disease stage. No statistical significant differences were found between normal pancreas and PDAC in the expression of Nestin, Notch1, 3 and 4, ABCG2 or ALDH1. Notch2 and Jagged1 and 2 expression were increased in PDAC. CD133-positive cells were above-normal in PDAC, but the difference was not statistically significant. Nestin, Notch1-4, Jagged1, ABCG2 and ALDH1 immunostaining scores were not correlated with tumor grade or disease stage. CD133 and Notch2 expression was significantly inversely correlated with tumor grade, but not disease stage. Notch3 immunostaining positively correlated with tumor stage, but not with differentiation grade. Jagged2 protein expression correlated inversely with disease stage, but not with tumor grade. From the clinical standpoint, improved delineation of the tumor CSC signature, putatively responsible for tumor initiation and recurrence after initial response to chemotherapy, may offer novel therapeutic targets for this highly lethal cancer.     

应用图像处理对食管癌软组织块影术前判断的研究

采用NAI200医用图像处理系统,对100例食管癌上消化道钡餐X线片上软组织块影,进行分析,作出诊断和手术切除可能性的判断。研究结果说明,经过图像处理过的X线片,能清楚地显示出肿瘤的大小、范围、肿瘤与周围组织的关系等,从而能判断肿瘤能否切除的可能性。     

Enhancement by Nano-Diamino-Tetrac of Antiproliferative Action of Gefitinib on Colorectal Cancer Cells: Mediation by EGFR Sialylation and PI3K Activation

Drug resistance complicates the clinical use of gefitinib. Tetraiodothyroacetic acid (tetrac) and nano-diamino-tetrac (NDAT) have been shown in vitro and in xenografts to have antiproliferative/angiogenic properties and to potentiate antiproliferative activity of other anticancer agents. In the current study, we investigated the effects of NDAT on the anticancer activities of gefitinib in human colorectal cancer cells. β-Galactoside α-2,6-sialyltransferase 1 (ST6Gal1) catalyzes EGFR sialylation that is associated with gefitinib resistance in colorectal cancers, and this was also investigated. Gefitinib inhibited cell proliferation of HT-29 cells (K-ras wild-type), and NDAT significantly enhanced the antiproliferative action of gefitinib. Gefitinib inhibited cell proliferation of HCT116 cells (K-ras mutant) only in high concentration, and this was further enhanced by NDAT. NDAT enhancedd gefitinib-induced antiproliferation in gefitinib-resistant colorectal cancer cells by inhibiting ST6Gal1 activity and PI3K activation. Furthermore, NDAT enhanced gefitinib-induced anticancer activity additively in colorectal cancer HCT116 cell xenograft-bearing nude mice. Results suggest that NDAT may have an application with gefitinib as combination colorectal cancer therapy.     

Low copy number and low oxidative damage of mitochondrial DNA are associated with tumor progression in lung cancer tissues after neoadjuvant chemotherapy

The decrease in the copy number of mitochondrial DNA (mtDNA) in cancer tissues might be associated with a decrease in oxidative mtDNA damage to achieve cancer immortalization and progression. Lung cancer specimens were collected from 29 patients with stage III non-small cell lung cancer (NSCLC) after neoadjuvant chemotherapy followed by surgical resection. The relative mtDNA copy number and the oxidative mtDNA damage (formation of 8-OHdG in mtDNA) of each cancer tissue were measured by quantitative real-time PCR. Seven female and 22 male lung cancer patients, with a mean age of 63.5 years were evaluated. Tumors of five patients became progressive, 13 stable, and 11 partially responsive after preoperative chemotherapy. Low mtDNA copy number (P=0.089) and low degree of oxidative mtDNA damage (P=0.036) were found to associate with tumor progression. Moreover, mtDNA copy number was significantly related to the degree of oxidative mtDNA damage (P=0.031). The mtDNA copy number and oxidative mtDNA damage were lower in advanced NSCLC after chemotherapy. This finding suggests that a decrease in the content of mtDNA may result in a decrease of mitochondrial density in cancer cells, which leads to a decrease of endogenous ROS production and reduction of ROS-triggered DNA damage to achieve immortalization.