ATTEMPTS TO ISOLATE C'3 ACTIVITY FROM PIG SERUM.

Gli autori descrivono un metodo per l'isolamento del terzo componente del complemento dal siero di maiale, basato sulla possibilita di provocare, per aggiunta di lisozima, passaggio in soluzione del C′3 precipitato insieme ad altre proteine in seguito all'aggiunta di opportune quantita di « Liquoid » al siero.

Arthus type inflammation with rat immunoglobulins.

Etude comparative des proprietes biologiques des anticorps IgM, IgG1 et IgG2 du rat. Les resultats montrent que le pouvoir agglutinant et lytique des anticorps IgM est respectivement 37 et 100 fois superieur a celui des deux classes d'anticorps IgG. Par contre, en ce qui concerne le phenomene d'Arthus, les anticorps IgM sont moins actifs que les anticorps IgG, si les rapports sont exprimes en poids. Si l'on calcule les rapports par nombre de molecules, les anticorps IgM sont aussi, dans ce cas, plus actifs que les IgG.

Histamine binding to H2 receptors stimulates phospholipid methylation in mast cells

Rat peritoneal mast cells incubated in vitro in the presence of L-[methyl-3H] methionine and exposed to histamine undergo a rapid but transient increase in phospholipid methylation. By using specific H1- and H2-receptor antagonists, and histamine analogues differing in their H2-receptor agonist potency, it has been demonstrated that this metabolic event is dependent on histamine binding to H2-receptors.

Prostaglandin production by human polymorphnuclear leucocytes during phagocytosis in vitro.

Human polymorphonuclear leukocytes were found to be able to synthetize and release substantial amounts of PGE2' when stimulated by a phagocytic stimulus such as zymosan particles coated with complement. Hydrocortisone, at a concentration of 10(-5) M, which proved to be effective in other biological systems, failed to inhibit phagocytosis and PG release.

Effects of hydrocortisone on binding of IgG or C3b-coated erythrocytes to human monocytes and polymorphonuclear leucocytes.