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41.
Jan-Kan Chen Ying-Tung Lau Jackson Chu 《In vitro cellular & developmental biology. Animal》1992,28(2):143-145
Summary Rat aortic endothelial cells were found to exhibit clonal variations in response to EGF stimulation in cell growth and prostacyclin
synthesis. EGF-induced growth and prostacyclin synthesis appeared to be regulated in a coordinated manner in that a clone
with a higher response to EGF growth stimulation also exhibited a higher response to EGF-stimulated prostacyclin synthesis.
This observation implys a possible involvement of prostacyclin synthesis in some of the biological effects of EGF on vascular
endothelial cells. 相似文献
42.
Summary Following the observation of a close sequence homology between the N-terminal moiety of the -chain of fibrinogen with large parts of-casein, the occurrence of a keratin domain in the middle section of the Achain is suggested. 相似文献
43.
Cytotoxic lymphocyte precursor units (CLP-U) were enumerated in the spleens of C57BL/6 mice 3 days after i.p. injections of synthetic thymopoietin32-36 (TP5). One hundred to 1000 ng TP5/mouse potentiated splenic CLP-U, this effect being detectable only after suboptimal allogeneic sensitization (with 1.2 x 10(5) mitomycin-C treated DBA cells). This elevation of CLP-U persisted in the injected mice for at least 14 days. Control peptide did not affect CLP-U. In vitro incubation of 0.01 to 0.1 ng/ml of TP5 with normal C57BL/6 spleen cells also enhanced CLP-U after suboptimal allogeneic stimulation; high concentrations of TP5 caused suppression of CLP-U and this was detectable with optimal sensitization conditions. Thus TP5, in vitro and in vivo, appears to regulate immune responsiveness and this regulation varies with TP5 dosage and with the immune stimulus. 相似文献
44.
Acid lipase activity in the livers of thyroidectomized rats is increased by administration of L-thyroxine. The response is dose-dependent and can be demonstrated within 12 h after treatment. L-Triiodothyronine also evokes a rapid increase in acid lipase activity, and this increase can be inhibited by coadministration of actinomycin D. 相似文献
45.
Plasmids of Synechococcus cedrorum and two Anacytsis nidulans strains were characterized physically, and a probable instance of spontaneous "curing" is described. 相似文献
46.
The isolation and characterization of a specific antibody population directed against the prothrombin activation fragments F2 and F1 + 2 总被引:10,自引:0,他引:10
H K Lau J S Rosenberg D L Beeler R D Rosenberg 《The Journal of biological chemistry》1979,254(18):8751-8761
We have raised antisera against human prothrombin activation fragment F2 in rabbits and have chromatographed the respective immunoglobulin G fractions on prothrombin-Sepharose, Pr1-Sepharose, and F2-Sepharose immunoadsorbents. The specific antibody population obtained was utilized to construct a double antibody radioimmunoassay capable of measuring as little as 0.8 ng/ml of this component. Our studies suggest that the immunoreactive site defined by this antibody population is most probably located within the negatively charged COOH-terminal region of F2. The immunologic expression of this area is unaffected by denaturation or reduction-alkylation of F2 as well as by attachment of polypeptide to the NH2-terminal of this component. However, the presence of covalently bound polypeptide at the COOH-terminal of F2 reduces its immunologic reactivity by 300- to 400-fold. Prothrombin, Pr1, and Pr*1, which contain the F2 region as part of their covalent structure, are at least 4000 to 7000 times less immunoreactive than F2 on a molar basis. Conversion of these components to thrombin as well as activation fragments generates the theoretically predicted level of immunoreactivity. Masking of the immunoreactive site within these zymogens is due to two phenomena. Firstly, covalent attachment of polypeptides on the COOH-terminal of the F2 segment significantly depresses the reactivity of this region. Secondly, a critical S--S bridge aids in the sequenstration of the immunoreactive site. This cross-link may facilitate interactions between the COOH-terminal of the F2 segment and other regions of the zymogen. 相似文献
47.
48.
In the female hamster, temporary sterility for a period of 10 or 15 days was induced by an intraperitoneal Silastic-PVP-tube containing 3.5 or 1.0 mg of PGF2alpha, respectively. All Silastic-PVP-PGF2alpha tube hearing animals regained fertility and delivered normal litters at various times after the placement of the tube. The release rate of 3-H-PGF2alpha from the Silastic-PVP tube was described and their potential use as a drug delivery system discussed. 相似文献
49.
In the female hamster, temporary sterility for a period of 10 or 15 days was induced by an intraperitoneal Silastic-PVP-tube containing 0.5 or 1.0 mg of PGF2α, respectively. All Silastic-PVP-PGF2α tube bearing animals regained fertility and delivered normal litters at various times after the placement of the tube. The release rate of 3H-PGF2α from the Silastic-PVP tube was described and their potential use as a drug delivery system discussed. 相似文献
50.