Chick embryo fibroblast cultures infected with Sendai virus were incubated with (3)H-uridine in the presence of actinomycin D beginning at 18 hr after infection. The 35 and 18S virus-specific ribonucleic acid (RNA) components were found in a ribonuclease-sensitive form in the cell and appeared to be associated with polyribosomes. Newly synthesized 57S viral RNA was rapidly coated with protein t...

Antithrombin is a plasma protein of the serpin superfamily that may occur as several conformational variants. The native form of antithrombin is a major regulator of blood clotting. In the present study, we have identified the mechanism underlying the antiangiogenic action of a heat-denatured form, denoted latent antithrombin. Fibroblast growth factor (FGF)-induced angiogenesis in the chick emb...

Fifteen strains of chlamydial agents, 2 Chlamydia trachomatis and 13 Chlamydia psittaci, were tested for plaque formation on chick embryo fibroblast cells. C. trachomatis strains did not form plaques; 12 strains of C. psittaci did form plaques and 1 strain did not. The distribution of plaque sizes with C. psittaci strains was studied and it was found that the 12 strains could be tentatively gro...

Seven days' space flight of fertilized chicken eggs pre- incubated for 7 and 10 days on earth caused no differences in the morphology of osteoblasts, osteoclasts, and osteocytes of humerus and tibia from those of control embryos. Bone-resorbing and -forming activities of the femur were not different between control and flight groups. As a consequence, calcium and phosphorus contents of the femo...

Fibroblast growth factor 4 (Fgf4) has been implicated as a regulator of mesoderm formation, posteriorisation, neural induction and neural patterning. Much of the evidence for this derives from studies in which exogenous FGF4 is applied to avian embryos. We have therefore examined expression of endogenous Fgf4 mRNA in the developing chick embryo at stages when these processes are occurring. Expr...

In the chick embryo, neural cells acquire midbrain, hindbrain, and spinal cord character over a approximately 6 hr period during gastrulation. The convergent actions of four signals appear to specify caudal neural character. Fibroblast growth factors (FGFs) and a paraxial mesoderm-caudalizing (PMC) activity are involved, but neither signal is sufficient to induce any single region. FGFs act ind...