[Endoluminal treatment of peripheral aneurysm with covered endoprosthesis]. / Traitement par voie endoluminale des anévrismes périphériques par endoprothèse couverte.

PURPOSE: To evaluate the feasibility and middle term patency results, for endovascular treatment of peripheral aneurysms, using covered stents. MATERIALS AND METHODS: Between December 1993 and may 2000 25 peripheral aneurysms on 24 patients, mean age 67.8 years (42-81), were treated with covered stents (Cragg EndoPro system or passenger, hemobahn, Word Medical). Aneurysm locations were: 17 iliac, 4 popliteal, 1 femoral, 1 subclavian, 1 carotid. The follow-up range from 1 to 75 months (mean 30.1 months). RESULTS: Successful aneurysm exclusion was achieved in all patients, while maintaining good lower extremity perfusion. All but one stent remained patent during the early follow-up period. At one year 94.4% stents were patent, at two years 90.2. CONCLUSION: Treatment of peripheral aneurysms with covered stents has a high rate of immediate procedural and clinical success. At middle term follow-up patency is encouraging except with popliteal procedure, however long term follow-up and larger series is warranted to assess the place of this procedure as an alternative to the surgery.

Long-term results of endovascular stent placement in the superior caval venous system.

PURPOSE: To present the long-term results in superior caval stenting for symptomatic obstruction. METHODS: Forty-nine stents were placed in 30 patients: 16 (53%) with malignant lesions, five (17%) with benign lesions and nine (30%) hemodialysis patients. Self-expandable stents were deployed on a first-line basis. Patients were followed clinically as well as by various imaging techniques and survival analysis was performed. RESULTS: Stent deployment was possible in all cases. Reocclusion was seen in 13 patients, of whom eight belonged to the hemodialysis group. Primary and secondary patency rates for malignant, benign and hemodialysis patients were respectively 74%, 50% and 22%, and 74%, 75% and 56% at 1 year. We had 7% complications and one death from iatrogenic superior vena cava injury. CONCLUSION: Primary stenting of superior caval obstruction is a first-choice treatment method achieving good mid-term patency. Patients with hemodialysis shunts must be closely monitored for early reintervention.

Structures of adenylosuccinate synthetase from Triticum aestivum and Arabidopsis thaliana.

Catalyzing the first step in the de novo synthesis of adenylmonophosphate, adenylosuccinate synthetase (AdSS) is a known target for herbicides and antibiotics. We have purified and crystallized recombinant AdSS from Arabidopsis thaliana and Tritium aestivum, expressed in Escherichia coli. The structures of A. thaliana and T. aestivum AdSS in complex with GDP were solved at 2.9 A and 3.0 A resolution, respectively. Comparison with the known structures from E. coli reveals that the overall fold is very similar to that of the E. coli protein. The longer N terminus in the plant sequences is at the same place as the longer C terminus of the E. coli sequence in the 3D structure. The GDP-binding sites have one additional hydrogen-bonding partner, which is a plausible explanation for the lower K(m) value. Due to its special position, this partner may also enable GTP to initiate a conformational change, which was, in E. coli AdSS, exclusively activated by ligands at the IMP-binding site. The dimer interfaces show up to six hydrogen bonds and six salt-bridges more than in the E. coli structure, although the contact areas have approximately the same size.

An Enzyme-Bound Bisubstrate Hybrid Inhibitor of Adenylosuccinate Synthetase.

Two relatively weak herbicides, hydantocidin phosphate and hadacidin were linked by a C(3) chain to afford a potent inhibitor (the 2S hybrid is shown) of the enzyme adenylosuccinate synthetase. The crystal structures of the bisubstrate-enzyme complexes were determined.

The mode of action and the structure of a herbicide in complex with its target: binding of activated hydantocidin to the feedback regulation site of adenylosuccinate synthetase.

(+)-Hydantocidin, a recently discovered natural spironucleoside with potent herbicidal activity, is shown to be a proherbicide that, after phosphorylation at the 5' position, inhibits adenylosuccinate synthetase, an enzyme involved in de novo purine synthesis. The mode of binding of hydantocidin 5'-monophosphate to the target enzyme was analyzed by determining the crystal structure of the enzyme-inhibitor complex at 2.6-A resolution. It was found that adenylosuccinate synthetase binds the phosphorylated compound in the same fashion as it does adenosine 5'-monophosphate, the natural feedback regulator of this enzyme. This work provides the first crystal structure of a herbicide-target complex reported to date.

[Cyclosporin A eyedrops in the prevention of high-risk corneal graft rejection. II. Postoperative clinical results]. / Cyclosporine A collyre dans la prévention du rejet de greffe de cornée à haut risque. II. Résultats cliniques post-opératoires.

Twenty-four patients (25 eyes) presenting a high corneal rejection risk have been treated by an association of topical cyclosporine A (2% in castor oil) and Dexamethasone eyedrops 1% 48 h preoperatively, the posology was slowly degressive postoperatively. The mean follow-up is of 12 months. Results are 19 clear grafts among which 4 had a reversible reject reaction, 3 unreversible rejections with a totally cloudy graft (12%), 3 corneal graft oedema of nonimmunologic nature allowing a counting fingers vision. A control group of 25 patients with the same high risks of rejection treated only by topical corticosteroids followed up for the same mean time showed an obvious higher rate of failure (65%).