Differential decrease of the central beta-adrenergic receptor in the rat after subchronic infusion of desipramine and clenbuterol

The effect of subchronic infusion of desipramine, a norepinephrine uptake inhibitor, and clenbuterol, a beta-adrenergic agonist, on the central beta receptor of the rat was determined using in vitro [³H]dihydroalprenolol binding. Desipramine produced significant decreases of the receptor in neocortex and hippocampal formation, and clenbuterol effected such decreases in corpus striatum and cerebellum. Both drugs caused a marked decrease in the activity of isoproterenol-sensitive adenylate cyclase in neocortex. The alpha₂ receptor of neocortex and cerebellum was unchanged by either drug as assessed by in vitro$\text{[}{}^3\text{H}\text{]p-}\text{aminoclonidine}$ binding. The results are discussed in terms of the different mechanisms of action of desipramine and clenbuterol, and the efficacy of these two drugs in the treatment of depression.     

Feedback suppression of the immune response in vivo. I. Immune B cells induce antigen-specific suppressor T cells

Stimulated lymphocytes are capable of synthesizing and secreting a variety of lymphokines which can affect the functions of several types of target cells. We report here the existence of a soluble factor released by activated human mononuclear leukocytes which produces a selective inhibition of human pulmonary fibroblast migration. This fibroblast migration inhibitory factor (FIF) was produced by antigen- or mitogen-stimulated human peripheral blood mononuclear leukocytes (PBML) and purified T cells. It inhibited the migration of ⁵¹Cr-labeled fibroblasts in a dose-dependent fashion with optimal effect (65–70% inhibition) obtained at 1:10 dilution and 8–20 hr of incubation. Sephadex G-100 fractionation revealed most activity to be found between 28,000 and 34,000 daltons. FIF was stable at 56 °C for 15 min, but destroyed at 80 °C or at low pH. This factor may play an important role in the modulation of fibrogenesis and healing processes by the immune system.     

Survival of the nuclear polyhedrosis virus of Heliothis armigera on crops and in soil in Botswana

Experiments are described that record the change in activity of the nuclear polyhedrosis virus of Heliothis armigera on cotton and sorghum in the short-term and long-term survival of the virus on sorghum and in soil. Virus activity was lost rapidly on cotton but remained at a high level for up to 30 days on sorghum. Activity was still detectable on harvested sorghum more than 80 days after spraying and on the soil below, but soil activity fell to less than one-third of its original level during the winter.     

Different iron(II) complexes of bleomycin A2

By 13C-nmr on iron-bleomycin preparations, an iron-bleomycin-CO complex is found that loses its CO upon standing, as demonstrated using 14CO. Iron-bleomycin, prepared without rigorous exclusion of oxygen, reacts with CO to a stable diamagnetic iron-bleomycin-CO complex.