The effect of the steroid sulfatase inhibitor (p-O-sulfamoyl)-tetradecanoyl tyramine (DU-14) on learning and memory in rats with selective lesion of septal-hippocampal cholinergic tract.

Dehydroepiandrosterone sulfate (DHEAS), is an excitatory neurosteroid synthesized within the CNS that modulates brain function. Effects associated with augmented DHEAS include learning and memory enhancement. Inhibitors of the steroid sulfatase enzyme increase brain DHEAS levels and can also facilitate learning and memory. This study investigated the effect of steroid sulfatase inhibition on learning and memory in rats with selective cholinergic lesion of the septo-hippocampal tract using passive avoidance and delayed matching to position T-maze (DMP) paradigms. The selective cholinergic immunotoxin 192 IgG-saporin (SAP) was infused into the medial septum of animals and then tested using a step-through passive avoidance paradigm or DMP paradigm. Peripheral administration of the steroid sulfatase inhibitor, DU-14, increased step-through latency following footshock in rats with SAP lesion compared to both vehicle treated control and lesioned animals (p<0.05). However, in the DMP task, steroid sulfatase inhibition impaired acquisition in lesioned rats while having no effect on intact animals. These results suggest that steroid sulfatase inhibition facilitates memory associated with contextual fear, but impairs acquisition of spatial memory tasks in rats with selective lesion of the septo-hippocampal tract.

Initial experience with a new Yamakawa-type prosthesis for long-term percutaneous transhepatic drainage.

BACKGROUND AND STUDY AIMS: In a previous study evaluating the problems of long-term percutaneous transhepatic biliary drainage (PTBD) using Yamakawa-type prostheses in patients with benign and malignant stenoses, breakage of the tube proved to be a serious problem, occurring in 19.7 % of PTBD exchanges. As a consequence of these results, a new PTBD tube made of Tecothane has been developed. PATIENTS AND METHODS: From September 1997 to September 1998, this new PTBD tube was applied in 64 patients (39 men, 25 women; median age: 70, range 29-89) in the treatment of benign (n = 30) or malignant stenoses (n=31; three stenoses remained indeterminate), and the course was followed. RESULTS: A total of 134 stent exchanges were performed, 52 of these being ahead of schedule (39 %). Not a single case of breakage occurred. However, other PTBD-related problems remained unchanged. Patients accepted the new prosthesis very well; among 19 patients who had experience of both the new one and the conventional one, 11 had preferences-eight for the new one and three for the old one. CONCLUSIONS: This new Tecothane prosthesis has solved the problem of PTBD breakage, which was often accompanied by serious problems. As was to be expected, other PTBD-related problems were not substantially affected. Nevertheless, this new tube represents progress in the percutaneous treatment of biliary stenoses.