Arabidopsis thaliana EPOXIDE HYDROLASE1 (AtEH1) is a cytosolic epoxide hydrolase involved in the synthesis of poly-hydroxylated cutin monomers.

Epoxide hydrolases (EHs) are present in all living organisms. They have been extensively characterized in mammals; however, their biological functions in plants have not been demonstrated. Based on in silico analysis, we identified AtEH1 (At3g05600), a putative Arabidopsis thaliana epoxide hydrolase possibly involved in cutin monomer synthesis. We expressed AtEH1 in yeast and studied its localization in vivo. We also analyzed the composition of cutin from A. thaliana lines in which this gene was knocked out. Incubation of recombinant AtEH1 with epoxy fatty acids confirmed its capacity to hydrolyze epoxides of C18 fatty acids into vicinal diols. Transfection of Nicotiana benthamiana leaves with constructs expressing AtEH1 fused to enhanced green fluorescent protein (EGFP) indicated that AtEH1 is localized in the cytosol. Analysis of cutin monomers in loss-of-function Ateh1-1 and Ateh1-2 mutants showed an accumulation of 18-hydroxy-9,10-epoxyoctadecenoic acid and a concomitant decrease in corresponding vicinal diols in leaf and seed cutin. Compared with wild-type seeds, Ateh1 seeds showed delayed germination under osmotic stress conditions and increased seed coat permeability to tetrazolium red. This work reports a physiological role for a plant EH and identifies AtEH1 as a new member of the complex machinery involved in cutin synthesis.

Transcatheter valve insertion in a model of enlarged right ventricular outflow tracts.

OBJECTIVE: Transcatheter pulmonary valve insertion has recently emerged as an alternative to surgery. To extend its indications to patients with a large right ventricular outflow tract, we previously developed an intravascular device that reduces the diameter of the main pulmonary artery, allowing the insertion of available valved stents. Here we report its use in a model of animals with an enlarged right ventricular outflow tract and pulmonary valve incompetence. METHODS AND RESULTS: The study comprised 33 sheep that first underwent surgical enlargement of the main pulmonary artery. We then intended to implant a filler percutaneously, followed later by the insertion of a valve. Three animals died during the intermediate stage. The remainder were humanely killed either immediately (group 1, n = 6) or after a mean follow-up of 1 (group 2, n = 12) or 2 months (group 3, n = 12). Animals from groups 2 and 3 were equally divided into 2 subgroups according to the difference between diameters of the device inserted and the main pulmonary artery (A < 5 mm, B > or = 5 mm). Fillers were all inserted successfully (n = 30), although one embolized after its insertion (group 3A). A valved stent was implanted in all animals, but in 1 case a balloon ruptured during inflation of the stent leading to incomplete expansion and the death of the animal. Six animals, 5 of which were from group A, had pulmonary regurgitation after valve insertion. CONCLUSION: Pulmonary valve insertion is possible through a transcatheter technique using a pulmonary artery filler. Oversizing the device reduces the risk of embolization and paraprosthetic leak.

Surgical management of pulmonary atresia with ventricular septal defect in late adolescence and adulthood.

OBJECTIVE: In presence of adequate pulmonary blood flow, patients presenting with unoperated or palliated pulmonary atresia with ventricular septal defect (PA/VSD) can reach adult age. However, they remain symptomatic with a limited life expectancy. METHODS: Since 1993, 27 patients underwent surgery for unrepaired PA/VSD. Median age was 20 (range: 15-43) years. Nineteen patients had 33 previous palliative procedures while eight were unoperated survivors. Major aortopulmonary collateral artery (MAPCA) had been observed in all but 2 and were still patent in 23. All bronchopulmonary segments were connected to the native pulmonary arteries (NPA) in 4 (type A), to both NPA and MAPCA in 18 (type B) and only to MAPCA in 5 (type C). The biventricular repair was performed in 17 patients: 3 type A, 12 type B and 2 type C. Ten patients underwent palliative procedure: eight aortopulmonary shunt, with unifocalisation in two and one right ventricle to NPA restrictive conduit. RESULTS: One (4%) hospital death occurred following the failure of a palliative procedure. No clinical improvement was observed in seven patients including one repaired and six palliated survivors. Two late cardiac death occurred 1 and 7 years after repair. At last visit, 15 of 16 repaired survivors were in NYHA class I or II. Only one patient awaits septation, while eight other with subsequent palliation were considered not repairable. CONCLUSION: The outcome was encouraging in patients who were eligible for completed biventricular repair. Although considered as unique alternative to cardiopulmonary transplantation, the justification for palliative surgery to improve pulmonary blood flow remains to be established.

Off-label use of an adjustable gastric banding system for pulmonary artery banding.

BACKGROUND: Pulmonary artery banding is proposed as a first palliation in infants with complex congenital heart disease and high pulmonary blood flow. In addition, it may be used to retrain the left ventricle. Optimal tightening may be difficult to obtain, leading to reoperation. An implantable device for pulmonary artery banding with telemetric control was recently developed allowing for repeated adjustments, but it is presently limited to patients weighing less than 20 kg. In large animals, we tested an off-label adjustable gastric banding system for pulmonary artery banding. METHODS AND RESULTS: Fourteen ewes weighing 50 to 75 kg underwent implantation of the Lap-Band device (BioEnterics Corp, Santa Barbara, Calif) around the main pulmonary artery through a left thoracotomy. All had functional evaluation with progressive occlusion and opening of the device at implantation and every 2 weeks until sacrifice immediately after implantation (group 1, n = 8), at 1 month (group 2, n = 3), at 3 months (group 3, n = 3), or death. Invasive pressure measurements in the right ventricle and aorta were carried out each time. Devices were easily implanted in all animals. Progressive occlusion and reopening were possible in all animals during each time point. Two animals died of right heart failure related to excessive tightening of the band. Retrieval of the device without any major damage was possible in 12 of 14 animals. CONCLUSION: With this implantable device, we were able to adjust the pulmonary artery diameter in animals. Patients requiring left ventricle retraining and weighing more than 30 kg would benefit from the device's use in humans.

Thermo-wrap technology preserves normothermia better than routine thermal care in patients undergoing off-pump coronary artery bypass and is associated with lower immune response and lesser myocardial damage.

OBJECTIVE: Perioperative hypothermia might be detrimental to the patient undergoing off-pump coronary artery bypass surgery. We assessed the efficacy of the Allon thermoregulation system (MTRE Advanced Technologies Ltd, Or-Akiva, Israel) compared with that of routine thermal care in maintaining normothermia during and after off-pump coronary artery bypass surgery. METHODS: Patients undergoing off-pump coronary artery bypass surgery were perioperatively and randomly warmed with the 2 techniques (n = 45 per group). Core temperature, hemodynamics, and troponin I, interleukin 6, interleukin 8, and interleukin 10 blood levels were assessed. RESULTS: The mean temperature of the patients in the Allon thermoregulation system group (AT group) was significantly ( P < .005) higher than that of the patients receiving routine thermal care (the RTC group); less than 40% of the latter reached 36 degrees C compared with 100% of the former. The cardiac index was higher and the systemic vascular resistance was lower ( P < .05) by 16% and 25%, respectively, in the individuals in the AT group compared with in the individuals in the RTC group during the 4 postoperative hours. End-of-surgery interleukin 6 levels and 24-hour postoperative troponin I levels were significantly ( P < .01) lower in the patients in the AT group than in the RTC group. The RTC group's troponin levels closely correlated with their interleukin 6 levels at the end of the operation ( R = 0.51, P = .002). CONCLUSIONS: Unlike routine thermal care, the Allon thermoregulation system maintains core normothermia in more than 80% of patients undergoing off-pump coronary artery bypass surgery. Normothermia is associated with better cardiac and vascular conditions, a lower cardiac injury rate, and a lower inflammatory response. The close correlation between the increased interleukin 6 and troponin I levels in the routine thermal care group indicates a potential deleterious effect of lowered temperature on the patient's outcome.

New insights in minimally invasive valve replacement: description of a cooperative approach for the off-pump replacement of mitral valves.

AIMS: The aim of the present study was to evaluate whether off-pump mini-invasive mitral valve replacement is possible after prior bioprosthetic mitral valve replacement in animals. METHODS AND RESULTS: To validate this concept for off-pump redo mitral valve insertion, we first replaced surgically mitral valves of six sheep under extracorporeal circulation using a Mosaïc valve. Prior to its insertion, we added a radio-opaque ring on its base to enhance its visualization under fluoroscopy. A bovine jugular valve mounted into a stent was then inserted off-pump through an opening of the atrial wall. Mitral valves were replaced successfully in all animals. Following the surgical valve insertion, mean left atrium and left ventricular end-diastolic pressures were 38 (22-42) and 18.8 mmHg (13-22), respectively. Angiography showed perfectly functioning valves, no subaortic valve obstruction, and a mild paravalvular leak in one animal. In one animal, we were unable to control the bleeding from the atrial opening. In this case, trans-atrial valvulation was not attempted. The off-pump valvular implantation was successful in the other five sheep. Haemodynamic data did not change after the insertion of valved stents. Implanted valves were all competent. The animal with the better haemodynamics was kept alive and is still alive 3 months after implantation. CONCLUSION: Surgically implanted bioprosthetic valves provide excellent support for off-pump insertion of a valved stent. Further experiments are necessary, in particular with appropriate valve size, before considering this approach for percutaneous mitral valvular replacement in patients with a dysfunctional bioprosthesis.