Dating Granites Using CODEX, with Application to In Situ Dating on the Moon

We have measured 87Rb–87Sr isochron ages for two granites, using the breadboard version of our Chemistry, Organics, and Dating EXperiment (CODEX), a laser-ablation resonance-ionization mass spectrometer designed for in situ geochronology on the Moon or Mars. These measurements extend the demonstrated analytical capabilities of CODEX, and indicate the value of incorporating a flight-ready version of CODEX, now under construction, into a future mission payload. We used CODEX to obtain accurate ages for the 1700 Ma Boulder Creek Granite, with 1σ statistical precision of 110 Myr, and for the 1100 Ma Pikes Peak Granite, with 1σ statistical precision of 160 Myr. To provide an end-to-end illustration of how CODEX analysis of granites can address critical lunar science questions regarding rock age and composition in situ, we describe an example mission to the lunar Gruithuisen Domes. Gruithuisen Domes appear to be volcanic edifices of granitic composition. Orbital remote sensing suggests that granitic rocks represent only a small fraction of the lunar surface, and the mere fact of their existence on the Moon is a puzzle. CODEX determination of the timing and process of their formation, both presently ill-understood, would provide important constraints on the thermal and geochemical evolution of the lunar interior

Revision of previous Fontan connections to total extracardiac cavopulmonary anastomosis: A multicenter experience

AbstractBackground: Conversion to total extracardiac cavopulmonary anastomosis is an option for managing patients with dysfunction of a prior Fontan connection. Methods: Thirty-one patients (19.9 ± 8.8 years) underwent revision of a previous Fontan connection to total extracardiac cavopulmonary anastomosis at four institutions. Complications of the previous Fontan connection included atrial tachyarrhythmias (n = 20), progressive heart failure (n = 17), Fontan pathway obstruction (n = 10), effusions (n = 10), pulmonary venous obstruction by an enlarged right atrium (n = 6), protein-losing enteropathy (n = 3), right atrial thrombus (n = 2), subaortic stenosis (n = 1), atrioventricular valve regurgitation (n = 3), and Fontan baffle leak (n = 5). Conversion to an extracardiac cavopulmonary connection was performed with a nonvalved conduit from the inferior vena cava to the right pulmonary artery, with additional procedures as necessary. Results: There have been 3 deaths. Two patients died in the perioperative period of heart failure and massive effusions. The third patient died suddenly 8 months after the operation. All surviving patients were in New York Heart Association class I (n = 20) or II (n = 7), except for 1 patient who underwent heart transplantation. Early postoperative arrhythmias occurred in 10 patients: 4 required pacemakers, and medical therapy was sufficient in 6. In 15 patients, pre-revision arrhythmias were improved. Effusions resolved in all but 1 of the patients in whom they were present before revision. The condition of 2 patients with protein-losing enteropathy improved within 30 days. Conclusions: Conversion of a failing Fontan connection to extracardiac cavopulmonary connection can be achieved with low morbidity and mortality. Optimally, revision should be undertaken early in symptomatic patients before irreversible ventricular failure ensues. (J Thorac Cardiovasc Surg 2000;119:340-6

Coronary artery bypass surgery in a patient with Kartagener syndrome: a case report and literature review

Kartagener syndrome consists of congenital bronchiectasis, sinusitis, and total situs inversus in half of the patients. A patient diagnosed with Kartagener syndrome was reffered to our department due to 3-vessel coronary disease. An off-pump coronary artery bypass operation was performed using both internal thoracic arteries and a saphenous vein graft. We performed a literature review for cases with Kartagener syndrome, coronary surgery and dextrocardia. Although a few cases of dextrocardia were found in the literature, no case of Kartagener syndrome was mentioned

Levels of troponin I and cardiac enzymes after reinfusion of shed blood in coronary operations

Background. Reinfusion of shed blood after coronary artery bypass grafting might increase the levels of cardiac enzymes with consequent difficulties in the diagnosis of perioperative myocardial infarction. Methods. Thirty consecutive patients undergoing coronary artery bypass grafting who bled at least 400 mL within the first 4 hours after operation underwent reinfusion of shed blood. Thirty consecutive patients who were not autotransfused served as control. All patients underwent enzyme determination (total creatine kinase, MB fraction, lactate dehydrogenase, and troponin I) in the shed blood and in circulating blood preoperatively, at arrival in the intensive care unit, and 6, 24, and 48 hours after operation. Results. The shed blood contained significantly higher concentration of cardiac enzymes than the circulating blood at all time intervals (p = 0.0001). The levels of creatine kinase, its MB fraction, and lactate dehydrogenase in circulating blood were significantly elevated in patients receiving autotransfusion up to 24 hours after autotransfusion. The blood levels of troponin I were not significantly different between the two group of patients at all time points. The percent fraction of MB did not increase after autotransfusion. Conclusions. The measurement of cardiac troponin I is a useful marker for the diagnosis of perioperative myocardial infarction in patients undergoing transfusion of shed blood after coronary operatio