In order to investigate the effect of human growth hormone on T lymphocytes, we utilized a clonogenic assay for mitogen-responsive human peripheral blood T lymphocytes. Lymphocytes were purified by density gradient centrifugation and incubated in the presence of phytohemagglutinin using a two-layer agar technique for CFU- T-lymphocyte culture. Nanogram concentrations of human growth hormone, ov...

1. A quantitative study of the growth of Clytia johnstoni is described. 2. The distance between hydranths is most commonly between 3 and 4 mm. The average internode lengths and their variability frequently differs not only between colonies but also between stolons of a single colony. The differences are therefore unlikely to be genetic ones. Occasionally much longer internodes occur (up to 8 mm...

The erythropoietic effect of various thyroid hormones has been studied using erythroid colony formation by canine marrow cells. Although erythropoietin was required for colony growth, physiologic levels of thyroid hormones significantly enhanced colony numbers. The order of potency of the thyroid compounds in their in vitro erythropoietic effect parallels their known calorigenic potency in vivo...