Modification, by a poly I:C injection, of organ distribution of intravenously injected murine lymphoma cells and of blood coagulability.

51Cr-or 111In-labelled murine lymphoma cells were injected IV in control and poly I:C-treated mice. The organ distribution (lung, spleen, liver) of radioactivity was measured 2 h after injection. The results showed that if cell injection was performed 1 day after poly I:C treatment, the modifications of organ distribution did not fit with the expectations from a reinforcement of the NK function in vivo. In NK-suppressed mice, poly I:C affected the distribution of radioactivity in spleen and liver in the same manner as in normal mice, suggesting that the action does not entirely depend on the NK system. Additionally to that, poly I:C injections affected coagulability of the plasma from treated mice, by prolonging the coagulation time. It is concluded that poly I:C exerts a complex action on circulation and fixation of lymphoma cells.

Antigenic properties of fibrinogen component of Hemaseel HMN subjected to the antiviral severe dry heat treatment.

The experiments in this work were focused on determination of the extent to which fibrinogen component of fibrin glue (Hemaseel HMN, Haemacure Biotech.) retained the conformation of the parent molecule after dry heat antiviral treatment (one hour at 100 degrees C). For this purpose antigenic structure of the fibrinogen component, heated and non-heated, was compared to that of control fibrinogens, i.e. the isolated one and the fibrinogen present in fresh human blood plasma. The analytic parameters CI50 and CIs were calculated from the competitive inhibition data obtained in ELISA systems using antisera to fibrinogen, plasmic fragments D and E, and to polypeptide chains A alpha, B beta, and gamma. These immunochemical analyses indicated that there was a modified expression of some fibrinogen epitopes probably resulting from unfolding of the A alpha chain and the better exposure of the E domain to the hydrated environment induced upon a heating procedure. Our data show that dry heat treatment of fibrinogen component is not associated with a significant overall conformational change of the molecule.

Cultured epidermal sheet grafting with Hemaseel HMN fibrin sealant on nude mice.

Grafting of cultured epidermal sheets is a promising technique for skin restoration in extensive burns, but the technique has some limitations, resulting in variable graft takes. These experiments were designed to evaluate the innocuity of Hemaseel HMN fibrin sealant in the grafting process and in vivo evolution of cultured epidermis. A total of 30 mice were grafted, 15 were controls, 15 received tissue sealant application before the deposition of the cultured human epidermal sheets. Seven days after transplantation, compared to controls, the percentage of graft take over the total surface area grafted was greater in animals that had received the tissue sealant application. No difference was found 14 and 21 days postgrafting. In contrast, the percentage of graft take over the bony area (spinal) was significantly increased in animals grafted with previous application of sealant compared to controls at 7, 14 and 21 days postgrafting. Immunohistological and ultrastructural analysis showed that the evolution of the cultured human epidermis after transplantation was similar in both groups. The basement membrane was well structured 21 days after transplantation. The sealant was present at 4 days but not at 21 days postgrafting. Therefore, we conclude that the application of fibrin sealant before cultured epidermal sheet deposition on nude mouse graft bed is innocuous and enhances their mechanical stability. Since in this nude mouse system Hemaseel HMN fibrin sealant increased the percentage of graft take over areas difficult to engraft, we think that it may be advantageous in cultured epidermal sheet grafting on burn patients.