Improved method for polyamine determination in TMV, a rod-shaped virus.

Polyamines were measured in viruses using different techniques. An improved method of polyamine analysis is reported for tobacco mosaic virus (TMV), a rod-shaped virus (95% protein and 5% RNA), based on HPLC of sonicated PCA-treated highly purified virus suspensions. This method allowed higher and more reliable recovery of TMV polyamines (putrescine, spermidine and spermine) when compared to the HPLC of non-sonicated samples and to thin layer chromatography. It is suggested that sonication acts on PCA-precipitated protein aggregates causing the release of trapped polyamine molecules.

Amniotic membrane diffusion chambers: a new possibility for pancreatic islet transplantation.

In order to avoid the host foreign-body reaction which is probably responsible for the long-term failure of the artificial membrane diffusion chambers currently used for protecting the implanted islet tissue from rejection, we tested the human amniotic membrane as a possible new tool for enclosing transplanted islets of Langerhans. Bag-shaped chambers were made with human amniotic membranes and the diffusion of 125 I-Insulin out and of D-glucose into the chambers was measured. The diffusion patterns of insulin and glucose were shown to be better than those described for the best artificial membranes, the 50% diffusion being reached at min 42 for 125 I-Insulin and at min 11 for D-glucose. Moreover, it was shown that no lymphocytes diffused into the amniotic membrane chambers. These results, together with the already known characteristics of the human amniotic membrane, induce us to propose it as a suitable material for further experimental work in islet tissue transplantation.