Growth factor receptor-bound protein 2 (Grb2) links tyrosine-phosphorylated proteins to a guanine nucleotide releasing factor of the son of sevenless (Sos) class by attaching to the former by its Src homology 2 (SH2) moiety and to the latter by its SH3 domains. An isoform of grb2 complementary DNA (cDNA) was cloned that has a deletion in the SH2 domain. The protein encoded by this cDNA, Grb3-3, did not bind to phosphorylated epidermal growth factor receptor (EGFR) but retained functional SH3 domains and inhibited EGF-induced transactivation of a Ras-responsive element. The messenger RNA encoding Grb3-3 was expressed in high amounts in the thymus of rats at an age when massive negative selection of thymocytes occurs. Microinjection of Grb3-3 into Swiss 3T3 fibroblasts induced apoptosis. These findings indicate that Grb3-3, by acting as a dominant negative protein over Grb2 and by suppressing proliferative signals, may trigger active programmed cell death.

We have used derivatized antisense oligodeoxynucleotides both in vitro and in vivo specifically to inhibit translation of the activated human oncogene Ha‐ras. The oligonucleotides (5′‐CCACACCGA‐3′) were targeted to a region of Ha‐ras mRNA including the point mutation G‐‐‐‐T at the 12th codon which leads to a Gly‐‐‐‐Val substitution in the ras p21 protein. They were linked to an intercalating agent and/or to a hydrophobic tail, both to increase their affinity for their mRNA target and to enhance their uptake by tumor cells. A cell‐free translation system was used to demonstrate an RNase H‐dependent specific inhibition of activated ras protein synthesis. 50% inhibition was observed at a concentration of 0.5 microM of the most efficient oligonucleotide (5′‐substitution with an acridine derivative and 3′‐substitution by a dodecanol chain). This inhibitory effect stems from a point mutation‐sensitive cleavage of the mRNA and it mirrors the growth inhibition obtained with T24 bladder carcinoma cells, which carry activated Ha‐ras. The proliferation of HBL100 cells (non tumorigenic human mammary cell line) which carry two copies of normal Ha‐ras was unaffected. This study shows that it is possible to design antisense agents that will inactivate the mutated oncogene but not the protooncogene which is generally essential to cell survival.

Renal transplantation usually is performed by placing the graft in the iliac fossa, anastomosing the renal vein to the iliac vein or, when this is not possible, to the vena cava. When vascular complications occur, particularly on the venous side, the position of the graft may have to be changed. This report describes orthotopic renal grafts and positioning of the organ with anastomosis to the splenic vessels. Venous drainage was established directly into the mesenteric-portal territory, with two cases to the portal vein and one to the inferior mesenteric vein. A new technique for the venous drainage of the renal graft is shown. We have used this model in two cases of infrarenal inferior vena cava thrombosis. The kidney was located in a retroperitoneal position, with venous drainage to the superior mesenteric vein through an orifice in the posterior peritoneum.

In recent years, portal arterialization has been used in liver transplantation to increase the portal flow, as a solution for singular technical problems. We have developed a new auxiliary liver transplantation model in the rat with portal arterialization, so the native hepatic hilium remains untouched, consisting on a graft with a previous 70% hepatectomy. It is sited on the right renal bed, joining the infrahepatic inferior vena cava (IVC) of the graft with the recipient IVC. With an abdominal aortic graft, we connect the recipient aorta with the portal vein from the auxiliary liver. All the animals survived at the seventh day. No thrombosis was seen in any graft and an important rejection was observed in all the fields. We have developed a new experimental model of an auxiliary liver with portal arterialization, avoiding the utilisation of the native hepatic hilium, necessary for the possible recovering of the proper liver in the case of a reversible fulminant hepatitis.