The effect of viruses on megakaryocytes in vitro (author's transl)

Bone marrow suspensions from adolescent rats contain 0.3% megakaryocytes; this rate decreases to almost zero within 72--96 h cultivation in vitro in Leighton tubes because of thrombocytopoesis. Such cultures were inoculated immediately after seeding with different viruses in high multiplicity. After infection with herpes simplex virus type 1 or adenovirus type 2, no deviation of the number and morphology of the megakaryocytes was seen when compared with control cultures. However, after infection with vaccinia virus and, still more marked, with Newcastle disease virus, morphological alterations and interference with thrombocytopoesis were seen. Furthermore, a considerable portion of the altered megakaryocytes persisted for 72--96 h. Finally, the cytoplasm of the megakaryocytes after infection with vaccinia virus or NDV, but not with HSV 1 or adenovirus 2, showed a specific immunofluorescence with antiviral antisera, which indicates a direct cellular involvement and multiplication of vaccinia virus and NDV in megakaryocytes.     

Biological activity in vitro and in vivo of different insulin derivatives (author's transl)]

The biological activities of des-octapeptide-insulin, des-AsnA21-des-AlaB30-insulin, des-GlyA1-des-PheB1-insulin and trimethionyl-insulin were studied in vitro and in vivo. In vitro we measured, using the isolated diaphragm of the rat, the disappearance rate of glucose in the incubation medium, the incorporation of glucose into the glycogen of the diaphragm and the apntilipolytic activity in the isolated fat cell model. The incorporation of [U-14C]glucose after intraperitoneal injection into the glycogen of the diaphragm and the fat pad tissue was studied in vivo, as well as the incorporation of 14C from [U-14C]glucose into the lipids of the fat pad tissue of the rat.     

Synthesis of cyclic AMP from renal cortex in vitro (author's transl)

The parathyroid-hormone sensitive adenylate-cyclase from renal rat cortex has been studied. Mg2+ acts as stimulator at a specific locus increasing the apparent Vmax slightly from 50 to 60 nmol of cAMP per gram of protein if the Mg2+ concentration increases from 3.25 to 16 mM, and decreases the apparent KM from 2 to 0.4 mM. Fluoride decreases the apparent KM from 5 mM in NaF concentrations of 0 to 2 mM in NaF concentrations 2 mM. Magnesium ion also decreases the apparent Ka for NaF.