Animal models for various types of cancer are of great help in the study of tumors and antitumor effects. Subcutaneous models have been widely utilized because they can be produced easily by subcutaneously implanting tumor cells into animals. Although subcutaneous models are very convenient for examining tumor development, they are definitely different from clinical manifestations of original tumors. In orthotopic animal models for internal tumors, however, it is difficult to examine tumor development without sacrificing animals. We demonstrate here that the occurrence and growth of liver tumors induced by oral administration of thioacetamide into rats were clearly observable by ultrasonography, and that the sonographic estimation was accurate. It was observed sonographically that the number and volume of liver tumors increased proportionately with TAA treatment periods. These results indicate that sonography is a useful and non-invasive method to investigate liver tumor development in rats.

Administration, Oral↗

PubMedDate not supplied

The p73 gene is not mutated in oligodendrogliomas which frequently have a deleted region at chromosome 1p36.3.

An allelic loss of the chromosome 1p36 region is frequently found in oligodendrogliomas, which suggests the presence of putative tumor suppressor gene(s) in the region. Since the p73 gene, which encodes a protein with significant homology with p53, is mapped to the 1p36.33 region, we examined genetic alterations of the p73 gene in oligodendrogliomas. We screened 10 specimens for mutation throughout the p73 coding regions by polymerase chain reaction (PCR)-single strand conformation polymorphism analysis and by sequencing aberrantly migrated PCR products. We found several polymorphic nucleotide changes, but no somatic mutations that caused an amino acid change. The p73 gene is thus unlikely to be a tumor suppressor gene for oligodendrogliomas.

Chromosome Deletion↗

PubMedDate not supplied

Proceedings: 23. Oscillatory state of mitochondria. 2.

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Animals↗

PubMedDate not supplied

Analysis of intrahepatic invasion of hepatocellular carcinoma using fluorescent dye-labeled cells in mice.

Despite intensive efforts in the treatment of hepatocellular carcinoma (HCC), its prognosis remains poor, mainly because of intrahepatic metastasis. It is, therefore, important to investigate the invasive and metastatic behavior of HCC. To examine this, murine HCC cells were labeled with the fluorescent carbocyanine dye, DiI and implanted under the capsule of the liver of syngeneic mice. Optimal conditions are described for labeling HCC cells with DiI. Histological analysis using fluorescent and confocal microscopes revealed that HCC cells migrate to and invade the adjacent portal vein, but not the adjacent central vein. Conversely, DiI-labeled hepatocytes were shown not to migrate in the liver. These results suggest that intrahepatic metastasis of HCC occurs by invading the portal venous system. Furthermore, it is indicated that orthotopic implantation of fluorescent dye-labeled tumor cells may be a convenient and useful method to investigate the invasive and metastatic behavior of various types of cancer.

Animals↗