These results suggest that islets may be differentiated from precursor cells in the pancreatic duct, and that stem cells exist even in adults.

The purpose of this study is to utilize the thermo-reversible gelation polymer in which the sol-gel transitting phase is reversibly changed by temperature in a three-dimensional culture system. Human cancer cells have been observed to form multicellular spheroids, whereas fibroblasts slowly develop into small spheroids with the culture medium including this polymer. This polymer has some advantages for use as a culture material, as follows: first, cancer cells grow three-dimensionally in the aqueous solution of this polymer; second, it is easy to harvest cells or spheroids in the aqueous solution of this polymer by simply cooling down the temperature; and third, the culture medium including this polymer is so translucent that the cells or spheroids can be observed through a phase-contrast microscope. We thus conclude that this polymer is a very useful material for three-dimensional cultures.

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Background/Aim: Ascites tumor cells from patients with peritonitis carcinomatosa were tested for cis-diamminedichloroplatinum (CDDP) sensitivity. The patients were divided into CDDP-sensitive and resistant groups. Survival and time to progression (TTP) rates were compared. Materials and Methods: 18 peritonitis carcinomatosa patients with class V ascites based on cytologic diagnosis were enrolled in this study. Chemosensitivity testing of the ascites tumor cells was done to determine their sensitivity to CDDP using a three-dimensional culture matrix of thermoreversible gelation polymer (TGP). CDDP at a dose calculated to achieve ascitic fluid drug levels equivalent to the IC₅₀ was given intraperitoneally to 12 CDDP-sensitive patients and 6 CDDP-resistant patients. Results: Both the median survival time and the median TTP were significantly longer in CDDP-sensitive patients than in CDDP-resistant patients (survival time 105 vs. 13 days, p = 0.019; TTP 90 vs. 5 days, p = 0.029). Conclusion: The results indicate the potential feasibility of controlling ascites in cancer patients in whom a maximal dose effect can be achieved with a minimal dose of chemotherapy.