Newly developed liquid-based cytology. TACAS™: cytological appearance and HPV testing using liquid-based sample.

Cell profiles determined by the thin-layer advanced cytology assay system (TACAS™), a liquid-based cytology technique newly developed in Japan, were analyzed in this study. Hybrid capture 2 (HC-2) was also performed using the liquid-based samples prepared by TACAS to ascertain its ability to detect human papillomavirus (HPV). Cell collection samples from uterine cervix were obtained from 359 patients and examined cytologically. A HC-2 assay for HPV was carried out in the cell specimens. All specimens were found to show background factors such as leukocytes. After excluding the 5 unsatisfactory cases from the total 354 cases, 82 cases (23.2%) were positive and 272 cases (76.8%) were negative for HPV. Cell specimens from 30 HPV-positive cases and 166 HPV-negative cases were subjected to 4 weeks of preservation at room temperature. Then, when subsequently re-assayed, 28 cases (93.3%) in the former group were found to be HPV positive and 164 cases (98.8%) in the latter group were found to be HPV negative. These results supported the excellent reproducibility of TACAS for HPV testing. A reasonable inference from the foregoing analysis is that TACAS may be distinguished from other liquid-based cytological approaches, such as ThinPrep and SurePath, in that it can retain the cell backgrounds. Furthermore, this study raises the possibility that cell specimens prepared using TACAS could be preserved for at least 4 weeks prior to carrying out a HC-2 assay for HPV.

Interaction between mesothelial cells and macrophages in the initial process of pleural adhesion: ultrastructural studies using adhesion molecules.

Detachment of mesothelial cells is an early step in adhesion of the human pleura. To elucidate this process, we used adhesion molecules as the targets of primary antibody and performed immunohistochemical staining of the mesothelial cells that cover the surface of the sites of pleural adhesion and the macrophages that migrate from connective tissue. The surface of the adhesion site that was formed as a result of edematous and villiform elongation of the connective tissue underlying the visceral pleura was covered with mesothelial cells. However, there was partial detachment of the mesothelial cells caused by adherence to macrophages that had migrated from within the connective tissue, and that adherence was mediated by adhesion molecules. We demonstrated that both mesothelial cells and macrophages each express both CD54 and CD11a, important adhesion molecules. It was surmised that the detachment of the mesothelial cells is the result of interaction with the macrophages via those adhesion molecules and that over time it progresses to pleural adhesion.

Immunohistochemical and ultrastructural studies of the effects of prednisolone on transformation of fibroblast to regenerated mesothelial cells.

We have proposed in the past that chest wall fibroblasts are transformed to regenerated mesothelial cells. This study was conducted to investigate the effects of prednisolone on the differentiation and migration of fibroblasts in their transformation to mesothelial cells. Rat fibroblasts harvested from intercostal thoracic wall specimens were cultured in culture medium until cell spheroids were formed. An experimental cell spheroid group to whose culture medium prednisolone had been added and a control spheroid group with no addition of prednisolone were then subjected to immunohistochemical and ultrastructural studies of the changes in the fibroblasts with the passage of time. On days 1 and 2 of culture, the fibroblasts in each group were cytokeratin negative. However, on day 3 the control group became cytokeratin positive, and ultrastructural observations revealed formation of macula adherens and microvilli. In contrast, the experimental group fibroblasts remained cytokeratin negative even on day 3, but became cytokeratin positive on day 5 of culture. Macula adherens and microvilli also manifested on day 5. Prednisolone inhibited the differentiation and migration of fibroblasts, but it was surmised that fibroblasts that have resisted from the effects of prednisolone finally differentiate into mesothelial cells which have formed macula adherens.

Immunohistochemical and ultrastructural study on effect of fibroblast growth factor on transformation of fibroblasts to regenerated mesothelial cells.

To elucidate the effect of fibroblast growth factor on the phenotypical conversion of fibroblasts to mesothelial cells, both immunohistochemical and ultrastructural examinations were carried out on cultured spheroids that were composed of fibroblasts obtained from the parietal pleura of rats with and without addition of antifibroblast growth factor receptor antibody. In the present study, antifibroblast growth factor receptor antibody was employed to block the effect of the autocrine component of fibroblast growth factor in the culture medium. Phenotypical conversion from fibroblast to mesothelial cells was clearly blocked in the experimental group, to which culture medium had been added with antifibroblast growth factor receptor antibody, whereas the control group, cultured without addition of antifibroblast growth factor receptor antibody, showed phenotypical conversion of fibroblasts that was confirmed by the development of macula adherens, microvilli, and positive expression of cytokeratin. These results indicate the possibility that fibroblast growth factor plays a key role in the process of phenotypic conversion of fibroblasts to regenerated mesothelial cells.