The motion of rigid twisted ribbon-like particles in shear flow is studied by computer simulation. It is shown that the twisted ribbon migrates in the vorticity direction in strong shear flow with the sign determined by the chirality: the right-handed particles and their mirror-imaged particles move in opposite directions. This enables the separation of chiral particles from the racemic mixture. The average migration velocity in the vorticity direction is studied as a function of the shear rate, the length, and the pitch of the particle.

These results suggest that increased expression of the cadherin-catenin cell-cell adhesion system in metastatic foci may play an important role in progression of metastatic colorectal carcinomas.

No abstract

The expression of CD44v6 is well known as a useful marker of tumor progression and prognosis in colorectal cancer. In this study, we evaluated the serum levels of soluble CD44 splice variants containing exon v6 (sCD44v6) and examined the histological expression of CD44v6 in patients with colorectal cancer. Serum samples were obtained from 44 primary colorectal cancer patients before surgery. We used enzyme-linked immunosorbent assay to determine the serum levels of sCD44v6. The expression of CD44v6 was examined by immunohistochemical staining of the primary tumors obtained from the same patients. Both the serum concentration of sCD44v6 and the expression of CD44v6 were significantly associated with lymph node metastasis (p < 0.05). Furthermore, the serum level of sCD44v6 was higher in those patients with CD44v6-positive tumor tissues (154.4 ± 34.8 ng/ml) than in those with CD44v6-negative ones (130.7 ± 32.3 ng/ml; p < 0.05). The 5-year survival rate was significantly lower in patients with high serum levels of sCD44v6 (52.4%) than in those with low levels of sCD44v6 (78.0%; p < 0.05), and it was also significantly lower in patients with CD44v6-positive cancer (42.1%) than in those with CD44v6-negative cancer (84%; p < 0.01). We concluded that preoperative elevation in the serum levels of sCD44v6 might be a prognostic indicator for patients with colorectal cancer.