Inhibitory activity of IL-6 on malaria hepatic stages

Addition of recombinant interleukin-6 (IL-6) to Plasmodium yoelii hepatic cultures resulted in a specific dose-dependent inhibition of parasite development. Time course experiments showed that, without any direct effect on free sporozoites, IL-6 exerts its action during both the early phase of infection and during the subsequent maturation of the schizonts. Elicitation of the oxidative burst appears to be one mechanism by which IL-6 interferes with the development of hepatic phase. Catalase and superoxide dismutase, two scavengers of hydrogen peroxide and superoxide anions, reversed the IL-6 mediated parasiticidal activity.     

Incorporation of thioamide linkages into a growing peptide under SPPS conditions improved by salt effects

Amino acid methyl dithioesters may be coupled in the presence of DMAP and salts to a growing peptide chain on a polymeric resin with high coupling yields and low racemization. © Munksgaard 1995.     

Involvement of macrophages in the pathology of toxic epidermal necrolysis

In toxic epidermal necrolysis (TEN), as in the 'epidermal type' of erythema multiforme, the necrotic epidermis is infiltrated with mononuclear cells. We studied the epidermal infiltrate in seven cases of TEN. About half the cells obtained from pieces of cleaved epidermis dissociated by trypsin were non-epithelial. On cytologic analysis, 80% of these foreign cells exhibited markers of macrophages, 15% were granulocytes and only 5% were lymphocytes (almost exclusively OKT8 T lymphocytes). Semi-thin sections of early prenecrotic lesions showed exocytosis of mononuclear cells within the epidermis with features of satellite cell necrosis and formation of colloid bodies. Almost all these mononuclear cells were macrophages as evidenced by endogenous peroxidase-positive granules. These findings suggest that some kind of macrophage-mediated cytotoxicity may play a role in the necrosis of epidermal cells during TEN.     

Complement Activation by Alginate–Polylysine Microcapsules Used for Islet Transplantation

Abstract: A foreign body reaction is frequently observed around implanted microcapsules of alginate–polylysine. Since complement activation can play a role in this reaction, we checked in vitro the ability of empty alginate–polylysine microcapsules to activate complement. Human serum was incubated with microcapsules, and complement activation was evaluated by two methods: the complement hemolytic activity (CH₅₀) and the assay of the C3adesArg fragment. The occurrence of complement activation in the presence of microcapsules was suggested both by a CH₅₀ decrease and by high C3adesArg levels despite C3adesArg adsorption to the capsule membrane. Capsule membrane protection against the cytotoxic effects of complement was also tested. No hemolysis occurred when microencapsulated sensitized sheep erythrocytes were incubated with activated complement. In conclusion, the microcapsule membrane can protect cells against activated complement fragments. Nevertheless, alginate–polylysine microcapsules do activate complement, and this effect must be considered for its use as an implant.     

EFFECTS ON GROWTH HORMONE SECRETION FOLLOWING INTRAVENOUS AND SUBCUTANEOUS INJECTIONS OF GROWTH HORMONE-RELEASING FACTOR (hGRF-44 NH2): COMPARISON OF IMMUNOREACTIVE PLASMA GRF LEVELS

The effects of subcutaneous administration of three doses of human growth hormone-releasing factor (hGRF-44 NH2 or hGRF) at doses of 100, 300 and 600 micrograms were studied in six normal young men. GH responses obtained with 100 and 300 micrograms were negligible. In contrast, the 600 micrograms dose gave a profile of response comparable in timing and magnitude to that obtained with i.v. hGRF at maximal effect doses (20, 80, 100 micrograms). Plasma immunoreactive hGRF levels (IR-hGRF) were compared after s.c. and i.v. hGRF. Mean maximal plasma concentrations were comparable with s.c. 600 micrograms and i.v. 20 micrograms. Peaks occurred earlier with i.v. hGRF (5 min as opposed to 15 min): however, return to undetectable values was obtained between 90 and 120 min after s.c. or i.v. injections. These data suggest a great loss of the peptide between the subcutaneous space and blood, without delayed absorption. High variability in plasma IR-hGRF concentrations between the subjects after the same s.c. doses was observed.