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Y M Fu

Publications and source records attributed to Y M Fu.

22 records · Page 2Linked to original sources
PubMed1991

Immunohistochemical localization of basic and acidic fibroblast growth factors in the developing rat heart.

BACKGROUND: We used biochemical and immunohistochemical techniques to investigate the expression and distribution of immunoreactive basic and acidic fibroblast growth factors (bFGF and aFGF, respectively) in the hearts of rat embryos (11-20 days of gestation) and of postnatal rats (1-35 days after birth). Our purpose was to assess the relation between the cellular distribution of these growth factors and histogenetic and morphogenetic events in the developing heart. METHODS AND RESULTS: Western-blot analysis of heparin-bound material from neonatal heart extracts identified a single band with a molecular weight of approximately 18 kD for both bFGF and aFGF. Five antibodies for bFGF and three for aFGF showed superimposable distribution of immunoreactive bFGF and aFGF in the heart at each stage examined. At the cellular level, these peptides were localized in the cytoplasm and extracellular matrix. In the myocytes, immunostaining was positive throughout the embryonic and neonatal periods. In the majority of the mesenchymal cells of the cushions and endothelial cells of endocardium and vessels, staining was also positive. In the smooth muscle cells of the aorta, other large arteries, and coronary arteries, immunostaining was intensely positive at early stages of development but became faint or negative with increasing cell differentiation. CONCLUSIONS: The wide distribution of immunoreactive bFGF and aFGF that we identified in the developing rat heart suggests that these growth factors play an important role in heart cytodifferentiation and morphogenesis. Their superimposable distribution may reflect functional interaction. The progressive changes in their distribution suggest a changing role for these peptides during organogenesis.

Animals↗
PubMed1991

Cytotoxic effects of a recombinant chimeric toxin on rapidly proliferating vascular smooth muscle cells.

BACKGROUND: Restenosis after percutaneous transluminal coronary angioplasty is associated with activation of medial smooth muscle cells (SMCs); they proliferate, migrate to the subintima, and narrow the vessel lumen. Cancer cells often express more cell surface receptors than do normal cells. This has allowed tumor cells to be specifically targeted using cytotoxic agents. We have examined whether a similar concept can be applied to rapidly proliferating but nontransformed SMCs. Pseudomonas exotoxin (PE; MW, 66 kDa) is a potent toxin that kills cells by inhibiting protein synthesis; its toxicity is diminished when its cell recognition domain is deleted to produce a 40-kDa protein (PE40). METHODS AND RESULTS: A complementary DNA encoding transforming growth factor alpha (TGF alpha) was ligated to that encoding PE40 and the chimeric toxin TGF alpha-PE40, which is cytotoxic to cancer cells displaying epidermal growth factor (EGF) receptors, was expressed in Escherichia coli. The ability of this toxin to kill proliferating SMCs was tested. When cells were seeded at low density (2,500 cells/cm2) and grown in medium supplemented with 10% fetal bovine serum, they were found to be rapidly proliferating; these cells were very sensitive to the cytotoxic effects of TGF alpha-PE40 (ID50, 4.0 +/- 0.17 ng/ml). In contrast, cytotoxicity was 30-fold less (ID50, 125 +/- 23 ng/ml; p less than 0.0004) when cells were in a quiescent state (grown in medium supplemented with 0.5% fetal bovine serum). CONCLUSIONS: Competition studies using excess EGF indicated that the cytotoxic effects of TGF alpha-PE40 are specifically mediated by the EGF receptor. EGF receptor binding analysis demonstrated that rapidly proliferating SMCs display 10-fold more EGF receptors than do quiescent SMCs in vitro. Thus, a chimeric toxin targeted toward the EGF receptor can selectively kill rapidly proliferating SMCs. Whether this toxin or other chimeric toxins directed against other cell surface receptors will effectively inhibit SMCs proliferating in vivo or be useful in preventing restenosis remains to be determined.

ADP Ribose Transferases↗
PubMed1990

Pituitary abscess-A case report.

Two hundred and five cases of pituitary lesion were treated in Tri-Service General Hospital up to March 1989. A case of pituitary abscess was diagnosed during operation. The primary clinical manifestations are consequent upon the pituitary dysfunction and the mass effect of the pituitary abscess. A pre-operative diagnosis of pituitary abscess is usually very difficult. Transsphenoidal drainage with an appropriate antibiotic coverage may provide an optimistic prognosis.

Abscess↗