Effect of intraventricularly injected ricin on protein synthesis in rat brain

Hyperuricaemia, Xanthine Oxidoreductase and Ribosome-Inactivating Proteins from Plants: The Contributions of Fiorenzo Stirpe to Frontline Research

The enzymes called ribosome-inactivating proteins (RIPs) that are able to depurinate nucleic acids and arrest vital cellular functions, including protein synthesis, are still a frontline research field, mostly because of their promising medical applications. The contributions of Stirpe to the development of these studies has been one of the most relevant. After a short biographical introduction, an overview is offered of the main results obtained by his investigations during last 55 years on his main research lines: hyperuricaemia, xanthine oxidoreductase and RIPs.

Anti-Thy-1 immunotoxin, OX7-saporin, destroys cerebellar Purkinje cells after intraventricular injection in rats

Thy-1 is an abundant surface glycoprotein of rat neurons. OX7 is a monoclonal antibody with high affinity for Thy-1. This study sought to determine if intraventricularly administered OX7 could serve as a carrier to deliver cytotoxin to neurons, thus destroying those neurons. Saporin (Sap), a ribosome-inactivating protein was disulfide-coupled to OX7 (OX7-Sap). OX7-Sap, OX7, saporin alone, pooled non-immune mouse IgG, and an irrelevant immunotoxin, RFT-1-Sap, were injected into the lateral ventricles of anesthetized adult rats. Animals were observed for 1-8 days. OX7-Sap-injected animals developed coarse head tremor and gait/truncal ataxia in a dose-dependent manner beginning 24 h or more after injection. All control animals remained healthy. After OX7 or OX7-Sap injection, immunoperoxidase staining for mouse IgG was most intense and specific in the molecular and Purkinje cell layers of the cerebellar cortex. Cresyl violet staining demonstrated destruction of the Purkinje cell layer in the OX7-Sap-treated animals but not in controls. These results indicate that intraventricular injections of OX7 can be used to deliver biologically active moieties to the Purkinje cells. This approach may prove useful in analysis of Purkinje cell function and as a model of cerebellar degeneration.