Isolated cleft of the mitral valve: distinctive features and surgical management.
ABSTRACT Controversy remains as to whether isolated cleft of the mitral valve and cleft of the atrioventricular septal defect are different entities. Our objectives were to provide a precise description of isolated cleft of the mitral valve and to clarify its surgical management and outcome.
Patients with surgical repair of isolated cleft of the mitral valve were included.
Ten patients (9 female) underwent repair at a mean age of 12.1 +/- 10.5 years and mean weight of 32.1 +/- 17.8 kg. Preoperative echocardiography showed mild or less than mild mitral regurgitation in 6 cases and moderate to severe regurgitation in 4. Intraoperative examination confirmed in all cases a cleft dividing the anterior leaflet of an otherwise normal mitral valve. Attachment of the cleft to the ventricular septum by accessory chordae was found in 3 cases whereas preoperative echocardiography found such attachments in 5. Direct suture of the cleft was performed in 9 cases, associated with repair of tricuspid valve straddling (n = 1), subaortic stenosis (n = 1), and ventricular septal defect (n = 1). One patient with thickened cleft's edges required an Alfieri-type repair. After a mean follow-up of 4.9 years (range, 1.3 to 11.9), all patients are asymptomatic without significant mitral regurgitation.
Echocardiographic description of isolated cleft of the mitral valve is not always as accurate as intraoperative analysis. This is a distinct morphologic entity from the cleft of the left-sided valve of atrioventricular septal defect, and seems associated with a strong female predominance, with various cardiac and extracardiac features. Surgical repair is successful with excellent midterm results.
- SourceAvailable from: Meryl S CohenCirculation 02/2011; 123(6):686-90. · 15.20 Impact Factor
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ABSTRACT: Two mammalian mitochondrial initiation factors have been identified. Initiation factor 2 (IF2(mt)) selects the initiator tRNA (fMet-tRNA) and promotes its binding to the ribosome. Initiation factor 3 (IF3(mt)) promotes the dissociation of the 55S mitochondrial ribosome into subunits and may play additional, less-well-understood, roles in initiation complex formation. Native bovine IF2(mt) was purified from liver a number of years ago. The yield of this factor is very low making biochemical studies difficult. The cDNA for bovine IF2(mt) was expressed in Escherichia coli under the control of the T7 polymerase promoter in a vector that provides a His(6)-tag at the C-terminus of the expressed protein. This factor was expressed in E. coli and purified by chromatography on Ni-NTA resins. The expressed protein has a number of degradation products in partially purified preparations and this factor is then further purified by high-performance liquid chromatography or gravity chromatography on anion exchange resins. IF3(mt) has never been purified from any mammalian system. However, the cDNA for this protein can be identified in the expressed sequence tag (EST) libraries. The portion of the sequence encoding the region of human IF3(mt) predicted to be present in the mitochondrially imported form of this factor was cloned and expressed in E. coli using a vector that provides a C-terminal His(6)-tag. The tagged factor is partially purified on Ni-NTA resins. However, a major proteolytic fragment arising from a defined cleavage of this protein is present in these preparations. This contaminant can be removed by a single step of high-performance liquid chromatography on a cation exchange resin. Alternatively, the mature form of IF3(mt) can be purified by two sequential passes through a gravity S-Sepharose column.Methods in Enzymology 02/2007; 430:59-78. · 2.00 Impact Factor
Conference Paper: High-speed, low-voltage modulation in circular WGM microresonators[Show abstract] [Hide abstract]
ABSTRACT: Novel approaches to obtain compact, high-speed, low-voltage modulators using circular microresonators are presented. Two different mechanisms, free carrier injection and depletion width modulation are considered. Frequency 3 dB bandwidths of over 8 GHz are achieved at modulation voltages less than 1V.Biophotonics/Optical Interconnects and VLSI Photonics/WBM Microcavities, 2004 Digest of the LEOS Summer Topical Meetings; 07/2004