Detection of p21ras mutations in colorectal adenomas and carcinomas by enzyme-linked immunosorbent assay.

Background: Point mutations of the ras protooncogene, primarily within codons 12 and 13, are commonly identified in colorectal carcinomas and large adenomas. Despite data suggesting that ras genotyping may have clinical significance with respect to colorectal cancer screening and prognosis, more widespread use has been limited because of the lack of a suitable assay system. The principal objective of this study was to assess the feasibility and validity of a qualitative enzyme-linked immunosorbent assay (ELISA) for detecting the four most common ras mutations in human colorectal tumors at the protein (p21ras) level.

A three-dimensional system for long-term culture of human colorectal adenomas.

Studies of the adenoma-carcinoma sequence in the colon and rectum have been limited by the paucity of experimental models of adenoma growth and progression. Progress recently was reported in the development of monolayer culture systems. The principal objective of this study was to develop a primary culture system for colorectal adenomas that would simulate three-dimensional in vivo growth.

Characteristics of invasive and noninvasive human colorectal adenocarcinoma cells.

A human colon adenocarcinoma cell line (LoVo) established from a lymph node metastasis was used to study properties associated with invasive tumor cells. Human amniotic membranes were used as invasion barriers to select highly invasive and noninvasive subpopulations of cells from the parent LoVo line. Enriched subpopulations were compared with respect to parameters associated with invasion.

Chemotherapy screening assay using 3-dimensional cell culture.

A new alginate culture method (ACM) was used to test the effects of vincristine and 5-fluorouracil (5-FU) on the commonly used human colon carcinoma cell line HT-29. Colorimetric analysis of viability following treatment with physiologically tolerated levels of vincristine showed significant reduction of the surviving cell population. Hematoxylin and eosin staining of sections of treated organoid growths corroborated the colorimetric analyses.

L-azaserine induced preneoplasia in the rat pancreas. A morphometric study of dietary manipulation (lipotrope deficiency) and ultrastructural differentiation.

Putatively preneoplastic, pancreatic atypical acinar cell foci (AACF) and nodules (AACN), collectively termed atypical acinar cell lesions (AACL), were induced in male Lewis rats by L-azaserine (300 mg/kg body weight [bw] in divided doses). Rats given carcinogen and then fed a lipotrope deficient (LD) diet developed a significantly greater number of larger lesions than animals fed complete diet throughout the experiment. It is suggested that lipotrope deficiency plays a promoting role in this model of pancreatocarcinogenesis.