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Biomedical subjects

L Schweigerer

Publications and source records attributed to L Schweigerer.

At least 55 records · Page 3Linked to original sources

Basic fibroblast growth factor and its relation to angiogenesis in normal and neoplastic tissue.

Basic fibroblast growth factor is a protein widely distributed in the organism. It can stimulate the proliferation and differentiation of many cells and it is extremely potent in inducing angiogenesis, the formation of new blood vessels. In this article, some of its structural and biological properties are reviewed. In particular, the possible implications of basic fibroblast growth factor in normal and tumor angiogenesis are considered.

Fibroblast Growth Factors↗

Characterization and identification of heparin-induced nonopioid-binding sites for beta-endorphin in human plasma.

We have characterized the specific binding of human beta-endorphin (1-31) to novel binding sites which are formed in human plasma or serum in the presence of heparin. The formation of the binding sites is temperature-dependent and does not occur in the presence of other anticoagulants, such as sodium-EDTA, sodium-oxalate, or sodium-citrate. The specific binding of 125I-beta H-endorphin to heparin-induced binding sites in human plasma is saturable and reversible. It is not inhibited by morphine or naloxone or by various opioid peptides which share their NH2-terminal opioid-active sequence with beta H-endorphin. In contrast, binding is inhibited by the COOH-terminal beta H-endorphin fragment Gly-Glu indicating that binding is to nonopioid sites. Electroimmunoprecipitation techniques revealed that these binding sites are identical with S protein/vitronectin or derivatives thereof. S protein is a plasma alpha 1-glycoprotein involved in attachment and spreading of cells and also in blood coagulation and complement activation. It is possible that the interaction of beta-endorphin with S protein is of physiological significance.

Binding Sites↗

Basic fibroblast growth factor: expression in cultured cells derived from corneal endothelium and lens epithelium.

We have examined the possible expression of fibroblast growth factor in cultured cells derived from bovine lens epithelium and corneal endothelium. Lens epithelial, but not corneal endothelial, cells were found to express the acidic fibroblast growth factor (aFGF) gene, whereas both cell types express the gene encoding basic fibroblast growth factor (bFGF), a related mitogen. Expression of bFGF was further examined. Both corneal endothelial and lens epithelial contain 3.7 and 7.0 k bFGF gene transcript, which are translated into material closely related, if not identical with bFGF. Essentially all of the bFGF-like material is bioactive, i.e. it can stimulate the proliferation of capillary endothelial or corneal endothelial cells and the stimulation is blocked by anti-bFGF antibodies. Our results indicate that bFGF derived from corneal endothelial and lens epithelial cells may act as a paracrine and autocrine growth factor in both cell types. Thus, bFGF present in both cell types may play an important role in the proliferation of injured or transformed ocular tissues.

Animals↗

Basic fibroblast growth factor is synthesized in cultured retinal pigment epithelial cells.

Cultured cells derived from bovine retinal pigment epithelium (RPE) express the basic fibroblast growth factor (bFGF) gene and they contain 3.7 and 7.0 kb bFGF gene transcripts which are translated into immunoreactive bFGF of Mr 17,500 and 18,000, respectively. The RPE cell-derived bFGF is bioactive, i.e., it can stimulate the proliferation of capillary endothelial cells and the stimulation of cell proliferation is blocked by anti-bFGF antibodies. We suggest that RPE cell-derived bFGF may be involved in the repair mechanisms following retinal injury and in the intravitreal pseudoneoplastic proliferation of the injured RPE.

Animals↗

Tumor necrosis factor inhibits the proliferation of cultured capillary endothelial cells.

We have examined the effect of tumor necrosis factor (TNF) on the proliferation of capillary endothelial cells derived from brain or adrenal cortex. In both cell types, TNF inhibits basal as well as basic fibroblast growth factor (bFGF)-stimulated cell proliferation. TNF induces an additional cytotoxic effect in bFGF-stimulated, but not in unstimulated, capillary endothelial cells. These results suggest that TNF could act as a negative regulator of angiogenesis in vivo and further, that TNF might induce selective cytotoxicity of capillary endothelial cells stimulated by tumor-derived bFGF. These results could explain why TNF induces hemorrhagic necrosis of certain, solid tumors.

Adrenal Cortex↗

Fibroblast growth factor: structural and biological properties.

Basic fibroblast growth factor (FGF) and acidic FGF are two closely related peptides that are multifunctional. They control proliferation, differentiation, and various other cellular functions in cells derived from the mesoderm and the neuroectoderm. The structural properties, genomic organization, and biological functions of both peptides in vitro or in vivo are reviewed. Their marked ability to enhance formation of connective tissue and vascular capillaries, as well as their involvement in limb regeneration, suggest several possible therapeutic applications.

Animals↗

Pituitary follicular cells produce basic fibroblast growth factor.

Cultured monolayers of bovine pituitary follicular cells, which transport ions, contain high amounts of mitogenic activity for endothelial cells which, on the basis of gene expression analysis, heparin-Sepharose elution profile, bioassay, immunoblotting, radioimmunoassay, and radioreceptor assay, has been identified as basic fibroblast growth factor (bFGF). These data indicate that follicular cells may be a major source of bFGF in the pituitary gland. Considering that bFGF has been proposed to play a role in paracrine regulation of pituitary hormone secretion, the data also suggest that these cells may exert important local regulatory functions.

Animals↗

Basic fibroblast growth factor in human rhabdomyosarcoma cells: implications for the proliferation and neovascularization of myoblast-derived tumors.

Cultured human embryonal rhabdomyosarcoma cells express the basic fibroblast growth factor (bFGF) gene and they produce bFGF, which is apparently composed of two microheterogenous forms with Mrs of 16,500 and 17,200, respectively. bFGF derived from the rhabdomyosarcoma cells stimulates their own proliferation and that of human or bovine vascular endothelial cells. It is conceivable that the rhabdomyosarcoma-derived bFGF stimulates the growth and neovascularization of human rhabdomyosarcomas and that it may thereby contribute to the development of these tumors.

Animals↗

Basic fibroblast growth factor as a growth inhibitor for cultured human tumor cells.

Basic fibroblast growth factor (bFGF) stimulates the proliferation of many cells and it is found in a wide variety of normal or transformed tissues. As demonstrated here, bFGF is also present in cultured human Ewing's sarcoma cells. Unexpectedly, however, bFGF isolated from these cells inhibits their own proliferation, indicating that bFGF can act as an endogenous (autocrine) growth inhibitor for cultured Ewing's sarcoma cells. Since bFGF also inhibits the proliferation of some further tumor cells, but stimulates that of others, it can be considered a bifunctional regulator of tumor cell proliferation. The autocrine growth-inhibitory effect of bFGF in Ewing's sarcoma cells may explain the low mitotic activity of Ewing's sarcomas.

Cell Division↗

Basic fibroblast growth factor: production and growth stimulation in cultured adrenal cortex cells.

Cultured bovine adrenal cortex cells express the basic fibroblast growth factor (bFGF) gene and contain, but under normal conditions apparently do not release, bFGF. However, once released, bFGF can stimulate proliferation of the cells, indicating that it could act as a self-stimulating growth factor for adrenal cortex cells. It is conceivable that the intracellular bFGF is released upon injury of the adrenal cortex and that it may be involved in the subsequent tissue repair mechanisms by stimulating the proliferation of adrenal cortical and vascular endothelial cells.

Adrenal Cortex↗

Bovine granulosa cells produce basic fibroblast growth factor.

Cultured bovine granulosa cells express the gene encoding basic fibroblast growth factor (bFGF). The bFGF gene is transcribed into 7.0- and 3.7-kilobase mRNA transcripts which are apparently translated into 16,000 mol wt bFGF-like growth factor. The granulosa cell-derived bFGF is bioactive, i.e. it can stimulate the proliferation of capillary endothelial or granulosa cells. This mitogenic effect is prevented by specific neutralizing anti-bFGF antibodies. Our results indicate that bFGF derived from granulosa cells can act as both autocrine and paracrine growth factor, and they further suggest that the factor may be involved in the development of the rich vasculature of the theca interna of the follicle.

Adrenal Cortex↗

Basic fibroblast growth factor is present in cultured human retinoblastoma cells.

Cultured human retinoblastoma cells express the basic fibroblast growth factor (bFGF) gene and they produce material similar, if not identical, to bFGF. The retinoblastoma-derived bFGF can stimulate the proliferation of capillary endothelial cells and this process is inhibited by anti-bFGF antibodies. It is conceivable that the retinoblastoma-derived bFGF contributes to the neovascularization of retinoblastomas.

Cell Line↗

Beta-endorphin: interaction with specific nonopioid binding sites on EL4 thymoma cells.

Binding of 125I-labeled camel beta-endorphin (125I-beta C-endorphin) to cells of several mouse thymoma cell lines was examined and was highest to EL4 cells. 125I-beta C-endorphin binding to EL4 cells was temperature-dependent; it was further characterized at 4 degrees C and exhibited saturability, complete reversibility, structural specificity and pH-dependence. 125I-beta C-endorphin binding was not inhibited by the opioid pentapeptides [Leu] enkephalin or [Met] enkephalin (which share common sequences with the N-terminus of beta C-endorphin) or by the N-terminal beta C-endorphin fragments beta C-endorphin (1-16) or beta C-endorphin (1-27). In contrast, binding was inhibited by beta C-endorphin (1-31), indicating that beta C-endorphin binding to EL4 cells was with a C-terminal beta C-endorphin segment. We suggest that binding of beta-endorphin to such nonopioid binding sites may precede its apparent effects on the proliferation of T-lymphocytes (5,6).

Animals↗