Appeal No. 1999-1510
Application No. 08/447,997
Background
The claims relate to the formation of “bioartificial organs,” or BAOs:
“devices which contain living cells and are designed to provide a needed
metabolic function to a host.” Specification, page 1. “For example, BAOs
containing insulin secreting cells may be used to treat diabetes.” Id.
The specification discloses that BAOs can be made using either
differentiated (non-dividing) cells or dividing cells. Use of non-dividing cells in
BAOs is preferred, because the number of cells in the BAO does not change
over time. Thus, for example, non-dividing cells would provide more predictable
results and a more stable dosage of the pharmaceutically active compound
secreted by the cells. Specification, page 3. However, the use of non-dividing
cells presents several problems: differentiated cells isolated from a donor must
be tested to ensure that they are free of pathogens, the cells can be damaged
during isolation, the amount of potential source material is limited, and non-
dividing tissue is difficult to modify genetically. Id., pages 3 -4.
The specification discloses a method that provides the benefits of both
dividing and non-dividing cells in BAOs.
According to this method, cell proliferation (i.e., mitosis) can be
inhibited or arrested by decreased expression of a proliferation-
promoting gene, such as an oncogene (e.g., c-myc, v-mos, v-Ha-
ras, SV40 T-antigen, E1-A from adenoviruses). Reduced
expression of the oncogene is achieved by downregulation,
repression or inactivation of the promoter driving oncogene
expression when the BAO is implanted in vivo in a host.
Upregulation, activation or derepression of the regulatable promoter
it as having been withdrawn. See MPEP § 1208 (“Grounds of rejection not argued in the
examiner’s answer are usually treated as having been dropped.”).
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