The effect of corticosteroids in the treatment of experimental bacterial endophthalmitis.

We evaluated the effects of the addition of corticosteroids to antibiotic therapy in the treatment of staphylococcal endophthalmitis in rabbits. Twenty-four hours after the induction of infection with Staphylococcus aureus, penicillin G, penicillin G and dexamethasone or prednisolone, or saline was injected retrobulbarly for ten days. Afterward, there was no ophthalmoscopic difference between the penicillin and corticosteroid-treated group and those animals receiving only penicillin G. At day 60, however, the fundus was visible in 64% of eyes treated with penicillin G with corticosteroids in contrast to 39% of those eyes treated only with penicillin G (P less than .025). The results between dexamethasone and prednisolone use were not significant. Retrobulbar corticosteroids in combination with effective antibiotic therapy effectively treated experimental bacterial endophthalmitis.

Large scale isolation of human erythrocyte membranes by high volume molecular filtration.

A molecular filtration procedure for preparing large quantities of human erythrocyte ghost membranes is presented. Hemolysate ghost membranes are rapidly cycled in the retentate channel of the filtration apparatus, while hemoglobin is removed as it passes through Pellicon filters into the filtrate channel. Several-liter quantities of washed packed erythrocytes can be processed in a few hours with this system, and the filtration procedure does not appear to alter intact erythrocyte or ghost membranes. Intact erythrocytes in isotonic solution can be circulated through the retentate channel for 16 h with only 3% hemolysis and with preservation of their original morphology in scanning electron microscopy. Ghost membranes isolated by the procedure are virtually identical in morphology, polypeptide composition and acetylcholinesterase content to membranes isolated by conventional centrifugation techniques.

Low-density lipoprotein preparation by combined diafiltration and ultracentrifugation.

A method for isolating low-density lipoprotein by combining diafiltration and ultracentrifugation is described. Diafiltration separates plasma components by use of an ultrafiltration membrane that excludes particles of molecular weight greater than 300,000. The retentate is concentrated three- to fourfold by ultrafiltration, allowing large-scale preparation of low-density lipoprotein. Low-density lipoprotein prepared in this manner is similar in physical, chemical, and biologic properties to low-density lipoprotein isolated by sequential density ultracentrifugation alone. When low-density lipoprotein, prepared by either method, was added to human umbilical vein endothelial cell cultures, no cytotoxicity was observed. The techniques described reduce the demand on multiple rotors and ultracentrifuges for large-scale preparation of low-density lipoprotein suitable and often needed for tissue culture studies.