Potentiation of the in vitro cytotoxic response to syngeneic lymphoma cells by soluble products of tuberculin-sensitive lymphoid cells stimulated with PPD

Spleen cells from rats immunized with the syngeneic (C58NT)D Gross virus induced lymphoma have previously been shown to differentiate into cytotoxic effector cells following restimulation with tumor cells in vitro. Previous work has also demonstrated that the addition of PPD-primed syngeneic spleen cells and PPD to cultures of (C58NT)D-primed spleen cells will potentiate the in vitro cytotoxic response to tumor antigens. In the studies presented here, the potentiating effect was found to be mediated by a soluble factor(s) released by nonadherent cells from BCG-primed rats. The release of this immunopotentiating factor(IPF) required the presence of PPD and varied with the concentration of PPD added. IPF was produced by BCG-primed spleen, lymph node, and thymus cells. Maximal production of IPF in PPD-stimulated cultures was obtained after 6–12 hr of incubation. Supernatants obtained after 30 hr of incubation lacked apparent IPF activity when tested initially, but activity was recovered after mild heat treatment. Recovery of IPF activity after heat exposure is best explained by the presence of a heat-labile inhibitor. IPF itself is stable to heat treatment to 56 °C for 40 min. IPF was also shown to be capable of enhancing immune responses to histocompatibility antigens in vitro.     

Intramolecular cyclization of pentose and hexose dithioacetals

The intramolecular cyclization of O-tosyl derivatives of dithioacetals of d-ribose, d-arabinose, and d-glucose was investigated. p-Toluenesulfonylation of d-glucose diethyl dithioacetal gave 3,6-anhydro-d-glucose diethyl dithioacetal. Variously substituted 5-O-tosyl-d-glucose dibenzyl dithioacetals gave derivatives of either 2,5-anhydro-l-idose dibenzyl dithioacetal, benzyl 1,5-dithio-l-idopyranoside, or l-idose dibenzyl dithioacetal. Likewise, 4-O-tosyl-d-glucose dibenzyl dithioacetal derivatives gave benzyl 1,4-dithio-d-galactofuranoside derivatives.     

Localization of corticotropin- and endorphin-related peptides in the intermediate lobe of the rat pituitary

Summary The question is examined whether -melanocyte stimulating hormone (-MSH), adrenocorticotropic hormone (ACTH), met-enkephalin and -endorphin are detectable by enzyme immunocytochemistry in the cells of the intermediate lobe (PI) of the rat pituitary. By applying antibodies against MSH, ACTH and -endorphin on light microscopic sections, intense immunostaining was found in all PI-cells. At the ultrastructural level, after treatment of consecutive serial sections with these three antibodies the immunoreactivity was localized in the same secretory granules. No specific metenkephalin immunoreactivity could be detected in the cells of the intermediate lobe.Supported by Deutsche Forschungsgemeinschaft SFB 87/B2     

Study of a possible structural relationship between thymopoietin and the facteur thymique serique

Background peptide chemistry, and the known 49-amino acid sequence of thymopoietin and the known 9-amino acid sequence of the facteur thymique serique (FTS) allowed the concept that Arg⁴⁹ of thymopoietin might be linked to Gln¹ of FTS in a new 58-amino acid peptide in tissue. Cleavage between Arg⁴⁹ and Gln⁵⁰ adjacent to the unique Lys⁴⁸-Arg⁴⁹ moiety could liberate thymopoietin and the [H-Gln¹]-FTS which could cyclize to FTS by the known reaction. In support of, rather than negating, this concept, synthetic FTS and the new dodecapeptide consisting of Val-Lys-Arg linked to the N-terminal of [H-Gln¹]-FTS showed comparable immune stimulating activity, $\text{in vivo}$; both peptides appeared more active than synthetic thymopoietin II.     

Inhibition of gastric acid secretion in dogs by neurotensin

Neurotensin is a tridacapeptide which has been isolated from bovine hypothalamus. The action of synthetic neurotensin was studied on gastric acid secretion in dogs provided with gastric pouches. Intravenously infused neurotensin, 50 ng × kg^?1 × min^?1, was found to produce a considerable inhibition of pentagastrin stimulated gastric acid secretion. On the other hand, there was no sign of inhibition of histamine induced gastric acid secretion. The experiments show that neurotensin, isolated from the central nervous system is a potent gastric secretory inhibitor and that it has a selective action in inhibiting gastric acid responses to pentagastrin but not to histamine.     

Genes inhibiting senescence in the ascomycete Podospora anserina.

Summary Senescence occurs in all wild strains of Podospora anserina after continued growth. This syndrome can be inhibited by a synergistic interaction of two linked genes, incoloris and vivax. Whereas the wild strain starts to become senescent after 26 d and the mutants incoloris and vivax after 42 and 66 d respectively, the double mutant shows no signs of aging after culture for more than one year.     

Book Reviews

Book reviewed in this article:
Archaeology: The Distribution of Compound Fishhook Types as a Gauge of Population Interaction in the Solomon Islands. Henry Cummings
Archaeology: A Style Analysis of Pottery Sherds from Nissan Island, Papua New Guinea: An Inquiry into the Prehistory of a Stepping Stone Island and its Role in Regulating Trade and Population Interaction between the Solomons and the Bismarck Archipelago. Susan Kaplan     

Stacking of safranine in liposomes during valinomycininduced efflux of potassium ions

Liposomes were prepared from phosphatidylcholine and cardiolipin in a KCl medium and suspended in a choline chloride medium with safranine. When efflux of K⁺ was induced by valinomycin, spectral shifts characteristic of stacking were observed. Ca²⁺ inhibited the rate of stacking in a competitive manner with a K_i of about 200 μM, while La³⁺ was about 10 times more potent. When liposomes were prepared from phospholipids with a higher ratio of cardiolipin to phosphatidyl-choline the inhibition was more potent. No effect on the stacking phenomena was seen when Ca²⁺ was added after the stacking was completed. When Ca²⁺ or an organic cation with four charges, spermine, was trapped in the intraliposomal compartment, no significant change in the rate of stacking was seen. However, the extent of stacking was decreased. It is suggested that safranine is driven by a diffusion potential to a site that is inaccessible to Ca²⁺ in the medium, presumably to the inner boundaries of the liposomal membranes.