Genomospecies identification and phylogenomic relevance of AFLP analysis of isolated and non-isolated strains of Frankia spp.

Amplified fragment length polymorphism (AFLP) was tested as an alternative to the DNA-DNA hybridization technique (DDH) to delineate genomospecies and the phylogenetic structure within the genus Frankia. Forty Frankia strains, including representatives of seven DDH genomospecies, were typed in order to infer current genome mispairing (CGM) and evolutionary genomic distance (EGD). The constructed phylogeny revealed the presence of three main clusters corresponding to the previously identified host-infecting groups. In all instances, strains previously assigned to the same genomospecies were grouped in coherent clusters. A highly significant correlation was found between DDH values and CGM computed from AFLP data. The species definition threshold was found to range from 0.071 to 0.098 mismatches per site, according to host-infecting groups, presumably as a result of large genome size differences. Genomic distances allowed new Frankia strains to be assigned to nine genomospecies previously determined by DDH. The applicability of AFLP for the characterization of uncultured endophytic strains was tested on experimentally inoculated plants and then applied to Alnus incana and A. viridis field nodules hosting culture refractory spore-positive (Sp+, that sporulate in planta) strains. Only 1.3% of all AFLP fragments were shown to be generated by the contaminant plant DNA and did not interfere with accurate genomospecies identification of strains. When applied to field nodules, the procedure revealed that Alnus Sp+ strains were bona fide members of the Alnus-Myrica host infecting group. They displayed significant genomic divergence from genomospecies G1 of Alnus infecting strains (i.e. Frankia alni) and thus may belong to another subspecies or genomospecies.

Endarterectomy of the ascending aorta: an alternative method in patients with extensively calcified (porcelain) aorta requiring aortic valve replacement.

A variety of surgical techniques have been described to manage the extensively calcified (porcelain) aortic root in patients requiring aortic valve replacement. We report two cases in which endarterectomy of the proximal ascending aorta was successfully performed. Endarterectomy of the left main coronary artery ostium was also performed in the one patient, and aortic root enlargement with patch aortoplasty in another. The technical aspects of the procedure and alternative approaches are discussed.

Endarterectomy for calcified porcelain aorta associated with aortic valve stenosis.

BACKGROUND: A calcified porcelain aorta may complicate aortic valve insertion and require an alternative, more complex method for valve replacement. The reason for this is that sutures cannot be inserted through the calcific plates in the annulus and ascending aorta. METHODS: In 6 patients with an average age of 73.8 years (range, 65 to 81 years), we performed the simpler procedure of aortic endarterectomy of the calcific plates with the aortic valve replacement. We realized that there may be an increased risk of postoperative complications, particularly stroke. The calcific plates were fractured to allow debridement of the calcium. In addition, an end-arterectomy was performed of the left main coronary ostium in 2 patients, and 5 patients also had coronary artery bypass grafting performed. RESULTS: All 6 patients underwent successful operations without major complications. On follow-up, echocardiography or computed tomographic scans in 3 patients have not shown dilation of the ascending aorta. CONCLUSION: Endarterectomy of the aorta may be an option in the management of patients with calcification of the aorta.