Percutaneous vascular surgical closure of the brachial artery.

For the first time, a suture mediated closure device was used to obtain hemostasis after a catheterization procedure was performed via the brachial artery approach. Two successive catheterization procedures, using the right and left brachial arteries, were performed in a patient, contraindicated for a procedure through the femoral approach. In both cases the closures were successful and without complications. An aggressive anticoagulation regimen could safely be prescribed to this patient because of the percutaneous surgical achievement of hemostasis. This technique should provide interesting clinical benefits in selected patients undergoing catheterization via the brachial approach.

Transesophageal echocardiography in evaluation of atrial masses.

Clinical and transthoracic echocardiographic findings in 92 patients who had atrial mass lesions identified by transesophageal echocardiography were retrospectively analyzed. Transthoracic echocardiography failed to diagnose or misdiagnosed 16 patients with small (< 3 cm) atrial thrombi, patients with thrombi localized to the appendage, or patients with technically difficult studies. The 3 patients with atrial myxoma who were not detected or were misdiagnosed by transthoracic echocardiography had small tumors (< 3 cm) or origin from the free wall of the atrium away from the atrial septum. Transthoracic study also failed to diagnose or misdiagnosed normal anatomic variants in 17 of 32 patients. In conclusion, transesophageal echocardiography is superior to the transthoracic study in evaluating the etiology and significance of atrial mass lesions.

Transductional instability of Tn5-induced mutations: generalized and specialized transduction of Tn5 by bacteriophage P1.

Generalized transduction is commonly used to move transposon-induced mutations among bacterial strains by selecting for inheritance of a transposon-encoded resistance determinant. Although complete cotransduction of the resistance determinant and the chromosomal mutation might be expected, it is often found that when Tn5(Kan) insertion mutations are transduced by bacteriophage P1 most of the nonmutant kanamycin-resistant transductants area due to specialized transduction of Tn5. Such P1::Tn5 specialized transducing phage are not found when a mutant Tn5 element lacking a functional transposase is employed.