Biomedical subjects

K M Zahos

Publications and source records attributed to K M Zahos.

3 recordsLinked to original sources

PubMed2000

Application of membrane-based dendrimer/DNA complexes for solid phase transfection in vitro and in vivo.

In this study a general description of the use of solid support membranes as the device for DNA delivery mediated by PAMAM dendrimers is presented. In contrast to the other DNA carriers, dendrimer/DNA complexes retain the ability to transfect after drying, which enabled coating or incorporation of complexes into poly(DL-lactide-co-glycolide) or collagen-based bioerodable membranes. These studies provide support for the use of this technology for in vitro and in vivo transfection of skin cells. Expression of luciferase or green fluorescent protein from pCF1-Luc and pEGFP1 plasmids indicated that dendrimer/DNA complexes can mediate transfection after dissociation from the solid support and/or when retained on the surface of the membranes. Modification of the membranes by incorporation of an anionic lipid, phosphatidyl glycerol (PG) at 1-5% concentrations, resulted in more efficient in situ transfection, particularly with dendrimer/DNA complexes formed at the low charge ratios (1-5). We also report data supporting the feasibility of membrane-based dendrimer/DNA complexes, particularly formed at lower than neutralizing conditions, for topical in vivo delivery of DNA to hairless mouse skin.

Administration, Topical↗

PubMed1998

Effect of interface/offset (I/O) adjustment on collection efficiency using the Fenwal CS3000 Plus Blood Cell Separator for peripheral blood progenitor cell collection.

Peripheral blood progenitor cells (PBPC) reside within the mononuclear cell (MNC) component of the blood and can be collected using a number of apheresis devices, including the Fenwal CS3000 Plus Blood Cell Separator. Increased MNC collection efficiency, therefore, may reduce the number of apheresis required to achieve collection goals. In this study, patients were divided into groups by absolute MNC count to determine the effect of interface detector offset (I/O) adjustment on MNC collection efficiency. Apheresis products from 104 procedures collected using a standard I/O setting of 100 were compared with 121 collections for which the I/O setting was adjusted according to the preapheresis MNC count. Adjustment of the I/O setting in this manner had no statistically significant impact on the per kilogram dose of MNC collected. The data did show that MNC collection efficiency was reduced as both the MNC count and I/O setting increased, as the collection efficiency was greatest for patients with the lowest peripheral MNC counts and was inversely correlated with the preapheresis MNC count. Although contamination of the product with platelets was drastically reduced at higher I/O settings, there was a concomitant rise in RBC contamination. We conclude that a standard setting of 100 is preferable to adjustment of the I/O setting as a function of the preapheresis MNC count.

Adult↗

PubMed1991

Expression of paragloboside-like lipooligosaccharides may be a necessary component of gonococcal pathogenesis in men.

To learn how lipooligosaccharide (LOS) phase variations affect pathogenesis, we studied two male volunteers who were challenged intraurethrally with Neisseria gonorrhoeae that make a single LOS of 3,600 daltons and sequentially followed LOS expression by gonococci as urethritis developed. LOS variation occurred in vivo. Signs and symptoms of gonorrhea began with the appearance of variants making 4,700-dalton LOS that are immunochemically similar to glycosphingolipids of human hematopoietic cells (Mandrell, R.E., J.M. Griffiss, and B.A. Macher. 1989. J. Exp. Med. 168:107) and that have acceptors for sialic acid. A variant that appeared at the onset of leukorrhoea was shed by 34/36 men with naturally acquired gonorrhea at the time they sought medical attention; the other two shed the variant associated with dysuria. None shed the challenge variant. These data show that in vivo phase shifts to higher molecular mass LOS that mimic human cell membrane glycolipids are associated with the development of gonococcal leukorrhea.

Carbohydrate Sequence↗