Cholesterol ester hydrolase in human red blood cells.

1. Cholesterol ester hydrolytic activity (sterol-ester hydrolase EC 3.1.1.13) was detected in human red blood cells. Enzyme activity appeared confined to the cell membrane and was most marked in washed preparations of red cell ghosts. 2. Hydrolytic activity was stimulated by the anti-oxidants D-alpha-tocopherol and butylated hydroxytoluene. Marked inhibition was produced by erythrocyte hemolysate, sodium taurocholate, and Triton X-100. 3. Optimal pH for the reaction was 5.4--5.7. 4. Because red cell cholesterol is all unesterified, it is speculated that the hydrolase serves to maintain the erythrocyte membrane free of esterified cholesterol.

Orbital floor reconstruction: a case for silicone. A 12 year experience.

INTRODUCTION: Controversy still exists regarding the choice of implant material for orbital floor reconstructions, in particular the use of silicone. We aimed to evaluate the long-term outcomes of orbital floor reconstructions with silicone versus other non-silicone implants. PATIENTS AND METHODS: We conducted a 12 year retrospective review of patients who had orbital floor reconstructions for fractures at the Royal Hobart Hospital, Tasmania, Australia, from 1995 to 2007. Surgical admission notes, CT reports, operation records, outpatient notes, and complications were recorded. Long-term follow-up consisted of a structured telephone interview assessing patient outcomes and satisfaction, including ongoing disability, following orbital floor repair. RESULTS: Eighty one patients were identified as having had orbital floor reconstruction with an implant. Mean long-term follow-up was 63 months. Outcomes of Silicone implants (n=58) were compared to non-silicone implant materials (n=23) including titanium mesh, 'Lactasorb', 'Resorb-X', autologous cartilage, and bone graft. Statistically significant advantages in the silicone group were found in the number of patients with palpable implants (24% vs 63%, p=0.005), the number of patients without any complaint (67% vs 32%, p=0.004), and the number of patients requiring subsequent surgery for complications related to their implants (5% vs 23%, p=0.046). CONCLUSION: The appropriate use of silicone implants for orbital floor reconstruction can have good results, contrary to much of the literature, with low complication rates including an acceptably low rate of infection and extrusion, as well as high patient satisfaction. To establish definite guidelines for best surgical practise, particularly amongst synthetic implant materials, prospective study is required.