Repair of carotid artery perforations during transsphenoidal surgery.

Background: Hemorrhage from carotid artery injury during transsphenoidal surgery is an unusual, but potentially fatal complication.

Methods: Among six patients experiencing laceration or perforation of the carotid artery, we treated four with a new technique using Teflon mesh and methyl methacrylate to form an external, artificial wall over the laceration and the carotid artery.

Results: In all four cases, hemorrhage was successfully controlled without neurologic deficit to the patient or complications frequently associated with the standard technique of nasal and sphenoid sinus packing removal.

Ventricular tachycardia: a life-threatening arrhythmia in a patient with congenitally corrected transposition of the great arteries.

Ventricular tachycardia (VT) is an uncommon finding in patients with congenitally corrected transposition of the great arteries (CCTGA). Cardiac death in patients with CCTGA has been attributed to complete heart block, systemic ventricular dysfunction, or severe AV valve regurgitation with heart failure. We describe the case of a patient who presented with palpitations and near-syncope that was associated with clinical episodes of VT.

Altered expression of the twist gene in young versus senescent human diploid fibroblasts.

We have recently reported the cloning and characterization of the human twist gene (H-twist), which encodes an evolutionarily conserved helix-loop-helix transcription factor. In several species, twist has been shown to play a role in mesoderm differentiation. We now report on the differential expression of H-twist as a function of in vitro life span in human diploid fibroblasts.

Cell-free transfer of cholesterol from lysosomes to phospholipid vesicles.

The objective of this work was to develop a cell-free system for studying the transfer of cholesterol from lysosomes to membrane acceptor particles. The methods involved: 1) loading of CHO cells at 15 degrees C with [3H]cholesteryl oleate-reconstituted LDL, such that it accumulated undegraded in endosomes; 2) homogenization of cells, followed by preparation of an endosome-lysosome donor fraction; 3) incubation of the donor fraction at 37 degrees C in a defined cytosol-like medium containing acceptor particles of egg phosphatidylcholine small unilamellar vesicles (PC-SUV); and 4) measurement of cholesteryl oleate (CO) hydrolysis and transfer of the resulting free cholesterol (FC) to vesicles. During cell-free incubation, LDL-loaded endosomes fused with lysosomes leading to the lysosomal hydrolysis of LDL cholesteryl ester.