摘要:

AbstractAcidic fibroblast growth factor (aFGF) is a potent mitogenin vitrofor many cells of ectodermal and mesodermal embryonic origin including skin-derived epidermal keratinocytes, dermal fibroblasts and vascular endothelial cells. Based on the mitogenic activity for these skin-derived cells, we tested the ability of topically applied aFGF to promote healing of full-thickness dermal wounds in healthy rodents. Low doses of aFGF can produce almost a two-fold maximum acceleration in the rate of closure of full-thickness dermal punch biopsy wounds in young healthy mice and rats. The mitogen also produces a 3 to 4 day acceleration in the time to complete closure in rats. Quantitative histomorphometric analysis of wound tissue shows that aFGF induces a marked stimulation of angiogenesis, granulation tissue formation and the growth of new epithelium, but does not promote dermal contraction. Application of aFGF to linear incisions in rat skin produces a transient increase in wound tensile strength accompanied by enhanced cellularity and deposition of collagen. Therefore, aFGF functions as a pharmacological agent that can accelerate dermal wound healing in rodents and could act therapeutically to promote dermal tissue repair in humans.

ISSN:0897-7194    

DOI:10.3109/08977199209023933

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractEvidence fromin vitrostudies strongly implicates basic fibroblast growth factor (bFGF) as a local regulator of ovarian function. However, thein vitrofunction of this growth factor in the ovary is uncertain. The objective of this study has thus been to investigate the biological role of bFGF in the rat ovary by monitoring bFGF gene expression usingin situhybridization in 3 systems; (1) the naturally cycling ovary, (2) ovaries of immature rats treated with diethylstilbesterol (DES), and (3) primary rat granulosa cell cultures. The rat estrus cycle can be divided into 4 stages as determined by vaginal cytology; diestrus, proestrus, estrus and metestrus. bFGF mRNA transcripts were localized to granulosa and theca cells of developing follicles during proestrus and estrus and in the corpus luteum following ovulation during metestrus. The estrogen analogue DES induced extensivein vitrofolliculogenesis and high levels of bFGF mRNA in both granulosa and theca cells when compared to controls. Detectable levels of bFGF mRNA were also observed in primary granulosa cell cultures grown to high density. Employment of thisin situhybridization procedure has enabled thein vitrocellular sources of bFGF mRNA to be identified and the time course of expression during the estrus cycle to be monitored. The biological significance of this expression and the interplay between bFGF, extra-and intra-ovarian modulators are discussed.

ISSN:0897-7194    

DOI:10.3109/08977199209023934

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThe rat mammary myoepithelial-like cell line Rama 401 possesses 46,000 high-affinity receptors (Kd52 pM) and 2.8106low-affinity receptors (Kd24 nM) for basic fibroblast growth factor (bFGF) per cell. Heparin or heparinase pretreatment of the cells inhibits the specific binding of [125I]-bFGF by over 70%, and abolishes binding to the low-affinity sites. Dissociation experiments suggest that there are three kinetically distinct low-affinity receptors, with dissociation rate constants of 3.8 s−1, 0.067 s−1and 0.0018 s−1. Consistent with the presence of low-affinity receptors possessing a slow dissociation rate constant, exogenously added bFGF bound to the low-affinity receptor can stimulate DNA synthesis in Rama 401 cells without being released into the bulk of the culture medium. These results suggest that the low-affinity receptors on Rama 401 cells are heparan sulfate glycosaminoglycans (HSGAGs) and that their ability to modulate the action of bFGF may result from their diverse range of dissociation rate constants. A cell line, Rama 401ts, derived from Rama 401 by transformation with a temperature sensitivesrcgene, deposits less extracellular matrix at the permissive temperature of 34 C than at the non-permissive temperature of 41 C. Whilst the binding of [125I]-bFGF to Rama 401ts cells at 41 C is identical to that observed with the parental Rama 401 cells, at 34 C there are fewer low-affinity receptors. These results suggest the (HSGAGs) low-affinity receptors on Rama 401 cells are associated at least in part with the extracellular matrix.

ISSN:0897-7194    

DOI:10.3109/08977199209023935

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractLeukemia inhibitory factor (LIF) is a cytokine previously shown to maintain pluripotent embryonic stem cells in their undifferentiated state. We have examined the effects of LIF in nullipotent embryonal carcinoma cell lines, and have found that LIF blocks differentiation induced by retinoic acid and at low temperature in OTF9 cells. LIF did not block differentiation in a parent F9 cell line. For OTF9 cells, LIF acts early in differentiation, inhibiting the appearance of parietal endoderm-type product cells. However, it acts subsequent to retinoic acid, and at least one early retinoic acid-induced event is unaltered in the presence of LIF. This finding provides both a means of dissecting the cascade of events leading to EC cell differentiation, and a well-characterised target cell type for studying the mechanism of action of LIF.

ISSN:0897-7194    

DOI:10.3109/08977199209023936

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractAngiogenesis plays critical roles in organ development during embryonic and fetal life, wound healing and in a variety of pathological conditions. Vascular endothelial growth factor (VEGF) is a secreted growth factor specific for vascular endothelial cells which induces angiogenesisin vivo. To gain a better understanding of the physiological role of VEGF, we have generated and characterized four murine monoclonal antibodies (mAbs) using the 165 amino acid species of recombinant human VEGF as immunogen. These mAbs (A3.13.1, A4.6.1, B4.3.1 and B2.6.2) belong to IgG1 isotype and have high affinities for VEGF (dissociation constants range from 2.2x10−8to 4x10−10M). Two different epitopes were detected with these mAbs. One epitope is recognized by mAbs A3.13.1 and B2.6.2, and the other recognized by mAbs A4.6.1 and B4.3.1. The epitope recognized by mAb A4.6.1 appears to be continuous while mAb B2.6.2 recognizes a discontinuous epitope. MAb A4.6.1 recognized three species of VEGF generated by alternative splicing, VEGF121, VEGF165and VEGF189while mAb B2.6.2 binds only VEGF165and VEGF189. Results using anin vitrobovine adrenal cortex endothelial cell proliferation assay, inin vivovascular permeability assay and anin vivoembryonic chicken angiogenesis assay showed that mAb A4.6.1 has potent VEGF neutralizing activities. MAb A4.6.1 was shown to block the binding of VEGF to its receptor(s) suggesting the inhibitory mechanism for VEGF activities.These well-defined mAbs should be very powerful tools to understand the structure-function relationship of various domains of VEGF and may have therapeutic potential.

ISSN:0897-7194    

DOI:10.3109/08977199209023937

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractOur previous studies have demonstrated that transforming growth factor e (TGFe) acts as a mitogen for epithelial and fibroblastic cells in both monolayer and soft agar. We have also identified TGFe in both normal and neoplastic tissues of mostly epithelial origin, and in body fluids. In this study we report on the purification of TGFe to homogeneity from bovine kidney using a multistep purification protocol which utilizes high performance electrophoresis chromatography in the final step. Amino acid analysis of TGFe revealed high content of proline, aspartate and glutamate. Examination of partial amino acid sequence indicated no similarity to other, already characterized, growth factors.

ISSN:0897-7194    

DOI:10.3109/08977199209023938

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractIntraperitoneal injection of Group A streptococcal cell wall (SCW) fragments into female Lewis rats results in the induction of an acute hepatic inflammation that progresses to granulomatous lesions. Kupffer cells have been shown to rapidly clear circulating SCW which triggers production of TGF-β. In this study, we examined Kupffer cells for the expression of TGF-βreceptors to determine if these cells might be modulated in an autocrine/paracrine fashion by TGF-βduring SCW-hepatic inflammation. By receptor crosslinking and subsequent SDS-PAGE analysis we demonstrate that Kupffer cells express Type I TGF-βreceptors, but not Types II and III. Scatchard analysis indicated a receptor density of approximately 1100 receptors per cell. Functionally, TGF-βwas found to be chemotactic for Kupffer cellsin vitroand this chemotactic response was higher in cells isolated from rats 1–21 days post SCW-injection. Although TGF-β1 mRNA is constitutively expressed by Kupffer cells,in vitrostimulation of the cultures with purified TGF-βaugments the expression of TGF-β1 mRNA and protein synthesis suggesting autocrine/paracrine regulation. These results indicate that TGFβsecreted by Kupffer cells during SCW-induced hepatic inflammation may amplify its own expression and regulate Kupffer cell functions relevant to the formation of granulomatous lesions within the liver.

ISSN:0897-7194    

DOI:10.3109/08977199209023939

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractActivated monocytes play an important role as producers of IL-6 during inflammation and immune response. We show that during monocytic differentiation of U-937 cells, induced by phorbolester (PMA), IL-6 mRNA expression was transiently up-regulated and IL-6 protein was secreted into the medium. In contrast, differentiation induced by VitD3 or Retinoic acid (RA) did not lead to an increase in the IL-6 expression. Thus, IL-6 expression does not seem to be associated with monocyte differentiationper se. However, U-937 cells terminally differentiated by VitD3, rapidly responded to bacterial lipopolysaccharide (LPS) induced activation by IL-6 expression and secretion. In cells, differentiated by PMA, the IL-6 expression was super-induced after activation by interferon-γ(IFN-γ) and LPS. The capacity of U-937 cells to respond to LPS activation by IL-6 expression was associated with the expression of CD14 and some serum components(s) were a prerequisite for a successful LPS induction. The IL-6R expression was down-regulated during monocytic differentiation of U-937 cells. In the terminally differentiated U-937 cells, the expression of IL-6R could be induced after activation by IFN-γand to a lesser extent by LPS, suggesting a mechanism by which activation positively regulates the response to IL-6 in macrophages.

ISSN:0897-7194    

DOI:10.3109/08977199209023940

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor