T cell adhesion and cytolysis of pancreatic cancer cells: a role for E-cadherin in immunotherapy?

Pancreatic cancer is an aggressive and potent disease, which is largely resistant to conventional forms of treatment. However, the discovery of antigens associated with pancreatic cancer cells has recently suggested the possibility that immunotherapy might become a specific and effective therapeutic option. T cells within many epithelia, including those of the pancreas, are known to express the αEβ7-integrin adhesion molecule, CD103. The only characterised ligand for CD103 is E-cadherin, an epithelial adhesion molecule which exhibits reduced expression in pancreatic cancer. In our study, CD103 was found to be expressed only by activated T cells following exposure to tumour necrosis factor beta 1, a factor produced by many cancer cells. Significantly, the expression of this integrin was restricted mainly to class I major histocompatibility complex-restricted CD8+ T cells. The human pancreatic cancer cell line Panc-1 was transfected with human E-cadherin in order to generate E-cadherin negative (wild type) and positive (transfected) sub-lines. Using a sensitive flow cytometric adhesion assay it was found that the expression of both CD103 (on T cells) and E-cadherin (on cancer cells) was essential for efficient adhesion of activated T cells to pancreatic cancer cells. This adhesion process was inhibited by the addition of antibodies specific for CD103, thereby demonstrating the importance of the CD103→E-cadherin interaction for T-cell adhesion. Using a 51Cr-release cytotoxicity assay it was found that CD103 expressing T cells lysed E-cadherin expressing Panc-1 target cells following T cell receptor stimulation; addition of antibodies specific for CD103 significantly reduced this lysis. Furthermore, absence of either CD103 from the T cells or E-cadherin expression from the cancer cells resulted in a significant reduction in cancer cell lysis. Therefore, potentially antigenic pancreatic cancer cells could evade a local anti-cancer immune response in vivo as a consequence of their loss of E-cadherin expression; this phenotypic change may also favour metastasis by reducing homotypic adhesion between adjacent cancer cells. We conclude that effective immunotherapy is likely to require upregulation of E-cadherin expression by pancreatic cancer cells or the development of cytotoxic immune cells that are less dependent on this adhesion molecule for efficient effecter function

Effects of cathode ray tube display formats on quality-assurance auditor's performance

The auditing process is a necessary and integral part of a quality-assurance system. The tendency of using computers in the auditing process is a necessity. This work describes three experiments designed to explore the effects of presenting written material variables on reading speed and comprehension. Five graduate students who consented to participate first completed the font style selection process among six Arabic font styles. "Simplified," "Traditional," and "Koufi" font styles were selected fromthe typography style selection process to be implemented in the next two experiments. Eleven auditors and fourteen undergraduate students with and without knowledge of using computers participated in the second and the third experiments. The font types (Simplified Arabic, Traditional Arabic, and Monotype Koufi) and the font sizes (10, 13, and 16 point) were independent variables in the second experiment. Color combinations (white/black, black/white, blue/white, and white/blue), column types (one and two columns) that are crossed within auditors and naive students were the independent variables in the third experiment. Reading speed, comprehension levels in terms of accuracy of answering recognition and recall questions, and discomfort subjective measures were the dependent variables in both experiments. Results showed that the quality-assurance auditors were superior to students at reading speed and comprehension. A 13-point Simplified Arabic font type was better than other font type and font size combinations in terms of reading comprehension and discomfort measure. In addition, white characters on a black background screen color was superior to other character\screen color combinations in terms of reading speed, reading comprehension, and discomfort measure..King Saud University, Riyadh, Saudi Arabi

Characterization and serology of the leafhopper-borne maize yellow stripe virus in Egypt

The nucleoprotein and non-capsid protein of maize yellow stripe virus (MYSV) were purified from naturally or experimentally infected maize or sorghum plants. In SDS-PAGE, the apparent molecular weight of the nucleoprotein was 35,6 KD, and that of the non-capsid protein was 14,7 KD. Similar to tenuiviruses, the nucleoprotein of MYSV was associated with fine filaments and the non-capsid protein formed typical needle-shaped crystals. Following a 2-day acquisition feeding period on MYSV-infected plants, vector leafhoppers (#Cicadulina chinai) remained highly infective for 21 days. Antisera to the nucleoprotein and non-capsid protein of MYSV were produced and used for detection of this virus in several host plants and vector leafhoppers in Egypt. Dot-blot and direct antigen coating (DAC) ELISA were used to detect MYSV in naturally or experimentally infected maize, wheat, barley, oat and the graminaceous weeds #Bromus wildenowii, #Cenchrus biflorus, #Dichanthium annulatum, #Digitaria sanguinalis, #Echinochloa colonum, #Setaria viridis and #S. verticillata. Dot-blot and DAC-ELISA were used also to detect MYSV in naturally or experimentally infective leafhoppers. (Résumé d'auteur

Head and neck cancer in South East England between 1995-1999 and 2000-2004: An estimation of incidence and distribution by site, stage and histological type.

Population-based data on head and neck cancer (HNC) stage and histological type are poorly described for England; these data are essential for clinical management and research. The aim of this study was to describe the distribution and incidence of all HNC and selected anatomical sites by sex, age, stage and histological type using a population-based cancer registry in South East England, and determine if the incidence changed between 1995-1999 and 2000-2004. We identified all HNC cancer cases registered by the Thames Cancer Registry for 1995-1999 and 2000-2004. Frequency distributions and age-standardised incidence rates were calculated by sex, age, stage and histological type and trends in incidence between the two time periods were described using incidence rate ratios and 95% confidence intervals. A total of 8700 HNC cases were reported in 2000-2004, representing an age-standardised incidence rate of 8.59 per 100000, which did not change significantly from 1995-1999. The three commonest HNC sites were intra-oral cavity, larynx and tonsil. Males were two to six times as likely as females to be diagnosed with HNC and there was a trend toward younger age at diagnosis over time. Significant increases in the incidence rate of intra-oral cavity cancer for both sexes and tonsillar cancer among males were observed. Conversely, laryngeal cancer incidence decreased over time. Staging data was only available for about 40% of HNC cases. Seventy six percent of HNC cases were squamous cell carcinomas. Trends in incidence varied between HNC sites, highlighting the importance of presenting data for individual HNC sites. The high proportion of unstaged cancers may result from incomplete recording in medical records; thus, the reporting of staging data should be made a priority

Characterization and serology of the leafhopper-borne maize yellow stripe virus in Egypt

The nucleoprotein and non-capsid protein of maize yellow stripe virus (MYSV) were purified from naturally or experimentally infected maize or sorghum plants. In SDS-PAGE, the apparent molecular weight of the nucleoprotein was 35,6 KD, and that of the non-capsid protein was 14,7 KD. Similar to tenuiviruses, the nucleoprotein of MYSV was associated with fine filaments and the non-capsid protein formed typical needle-shaped crystals. Following a 2-day acquisition feeding period on MYSV-infected plants, vector leafhoppers (#Cicadulina chinai) remained highly infective for 21 days. Antisera to the nucleoprotein and non-capsid protein of MYSV were produced and used for detection of this virus in several host plants and vector leafhoppers in Egypt. Dot-blot and direct antigen coating (DAC) ELISA were used to detect MYSV in naturally or experimentally infected maize, wheat, barley, oat and the graminaceous weeds #Bromus wildenowii, #Cenchrus biflorus, #Dichanthium annulatum, #Digitaria sanguinalis, #Echinochloa colonum, #Setaria viridis and #S. verticillata. Dot-blot and DAC-ELISA were used also to detect MYSV in naturally or experimentally infective leafhoppers. (Résumé d'auteur