In this study, a polycationic substance which is produced by cystic fibrosis fibroblasts and secreted into the growth medium has been identified and characterized with respect to its action on the efflux of putrescine from normal fibroblasts. Comparison of medium extracts from various cystic fibrosis homozygotes, heterozygotes and where possible normal fibroblasts from family groups have been undertaken in order to determine the relationship of this factor to the putative abnormal gene in cystic fibrosis. Physiological characterization of the factor secret-by cystic fibrosis homozygotes into fibroblast medium with respect to its effect on putrescine efflux in normal fibroblasts, including comparisons with the known membrane active substance polygalactosamine, has been pursued in order to delineate the possible role of cystic fibrosis factor in the pathophysiology of the disease. / The cystic fibrosis factor from medium is capable of causing the efflux of exogenously supplied putrescine. This activity is enhanced in the presence of extracellular calcium. Efflux of exogenously supplied putrescine is used as a bioassay for the cystic fibrosis factor. The putrescine efflux assay can be used as a quantitative bioassay for the cystic fibrosis factor. The response of the cystic fibrosis factor in the presence of calcium distinguishes it from polygalactosamine. The cystic fibrosis factor is found in medium from all homozygote and heterozygote cell lines tested but not in media from normal cell lines. It is proposed that the ability of the cystic fibrosis factor to alter the membrane permeability of cells and allow influx of extracellular calcium may be the underlying lesion which expresses itself phenotypically as cystic fibrosis. A model for the mode of action of the cystic fibrosis factor is presented. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0819. / Thesis (Ph.D.)--The Florida State University, 1980.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74175 |
| Contributors | STARNES, MARY MILDRED., The Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 157 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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