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Dissertation Information for Michael Becich

NAME:
- Michael Becich
- (Alias) Michael John Becich

DEGREE:
- Ph.D.

DISCIPLINE:
- Pathology and Laboratory Medicine

SCHOOL:
- Northwestern University (USA) (1983)

ADVISORS:
- None

COMMITTEE MEMBERS:
- None

MPACT Status: Incomplete - Inspected

Title: TUMOR HETEROGENEITY IN THE TRANSPLANTABLE PANCREATIC CARCINOMA OF RAT: ISOLATION OF DISTINCT NEOPLASTIC SUBPOPULATIONS TO STUDY CYTODIFFERENTIATION

Abstract: "The transplantable pancreatic acinar carcinoma demonstrates heterogeneity of cytodifferentiation with cell types ranging from those containing abundant, well-developed zymogen granules to those with a virtual absence of secretory granules. This spectrum of cytodifferentiation mimics that of normal embryonic acinar cell development in the pancreas. Two relatively homogeneous subpopulations of cells were isolated from this neoplasm by isopyknic gradient centrifugation. One subpopulation, termed granule enriched fraction (GEF) contained morphologically differentiated cells with abundant mature zymogen granules. The other subpopulation, consisted of poorly differentiated cells with immature cytodifferentiation and was termed granule deficient fraction (GDF) cells. The isolation of these tumor cell subpopulations was central to developing a model to study tumor heterogeneity without necessitating prolonged in vitro passage of subcloned cells which can alter surface properties and morphogenetic programming in epithelial cells.
GEF and GDF cells were studied by morphometric and biochemical methodologies to characterize the distinct differences in nuclear:cytoplasmic ratio, secretory granule content, degree of polarity and cytodifferentiation, and pancreas specific enzyme activity levels. Synthesis, intracellular transport, and storage of secretory proteins in GDF and GEF cells was studied by electron microscopic autoradiography and immunocytochemistry in these cells with distinctly different cytodifferentiation. GEF cells process secretory proteins in a manner reminiscent of normal pancreatic acinar cells and retain the essential regulatory controls of the secretory process. GDF cells appear to synthesize proteins, but appear unable to concentrate and store exportable proteins. Autoradiographic analysis of {('3)H}-thymidine incorporation revealed that 20% of the cells in the GDF subpopulation and 12% of the cells in the GEF subpopulation synthesize DNA. Both subpopulations produce tumors when injected subcutaneously. Concanavalin A receptor sites were found on GDF and GEF cell surfaces in contrast to normal pancreatic embryogenesis, in which receptors are discerned only in acinar cells containing mature cytodifferentiation. These studies provide a suitable model system for investigation of neoplastic cell cytodifferentiation and the role of tumor cell interactions in neoplastic progression."

MPACT Scores for Michael Becich

A = 0
C = 1
A+C = 1
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-01-31 06:25:05

Advisors and Advisees Graph

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Students under Michael Becich

ADVISEES:
- None

COMMITTEESHIPS:
- Sujin Kim - University of Pittsburgh (2003)