Cell cycle progression is monitored by checkpoint mechanisms to ensure the integrity of the genome and the fidelity of sister chromatid separation. Failure of such checkpoint functions results in genomic instability, a condition that predisposes cells to neoplastic transformation and tumor progression. Recently, Scolnick and Halazonetis defined a new mitotic checkpoint that acts at prophase and delays chromosome condensation in response to mitotic stress, and identified a gene, named checkpoint with FHA and ring finger (Chfr), that seems to be required for delaying prophase in human cells. In the present study, we examined human Chfr mRNA expression in 15 human esophageal cancer cell lines and 43 primary esophageal cancers to investigate the potential involvement of Chfr in the pathogenesis of esophageal cancers. We report here that a significant proportion of human esophageal cancer has loss of expression of Chfr gene. Furthermore, we found aberrant hypermethylation of the promoter region of this checkpoint gene in four of 15 (26.7%) esophageal cancer cell lines and in seven of 43 (16.3%) primary cancers.

Detection of high PTTG1 expression in surgically excised esophagus tumor tissues might help to identify patients with aggressive disease who require adjuvant therapy and provide prognostic information.

In esophageal cancer tissues, the expression of PPAR gamma was decreased compared with normal esophageal epithelium. The mRNA expression level of PPAR gamma may be a marker of prognosis after operation in esophageal cancer patients.

The dynamics of the stirred tank reactor polymer electrolyte membrane (STR‐PEM) fuel cell arise from the balance between water production and water removal within the cell. This results in STR‐PEM fuel cell steady‐state multiplicity, remarkably analogous to that of an autocatalytic exothermic STR. Model flooding effects in the cathodeside catalyst/gas diffusion layer by accounting for relevant mass‐transport processes is presented. We use the resulting STR‐PEM fuel cell model as a building block to construct approximations of more conventional integral (plug flow) type fuel‐cell reactors. This approach bypasses more complicated, distributed gas diffusion layer models. Connecting several STR‐PEM fuel cells in series, the effects of four operating parameters (temperature, external load resistance, inlet hydrogen and inlet oxygen flow rates) on the current evolution in each tank can be monitored and rationalized. © 2006 American Institute of Chemical Engineers AIChE J, 2006